Life Extension Magazine®

Issue: May 2010

Pomegranate

N-acetyl cysteine N-acetyl cysteine inhibits exercise-induced lymphocyte apoptotic protein alterations.

PURPOSE: To investigate the effect of strenuous exercise and antioxidant administration on pro- and antiapoptotic protein expression in intestinal lymphocytes. METHODS: Female C57BL/6 mice (N = 52) were randomly assigned to receive N-acetyl cysteine (NAC; 1 g.kg(-1)) or saline (SAL) 30 min before treadmill exercise (EX) for 90 min and 2 degrees slope (30 min at 22 m.min(-1), 30 min at 25 m.min(-1), and 30 min at 28 m.min(-1)) and sacrificed immediately (Imm) or 24 h (24 h) after exercise. Control mice were exposed to treadmill noise and vibration without running (nonexercised). Intestinal lymphocytes (IL) were isolated and pro- and antiapoptotic protein expression was evaluated by Western blot analysis. RESULTS: IL protein levels of proapoptotic (caspase 3 and cytosolic cytochrome c) and antiapoptotic (Bcl-2) were significantly different among groups. Relative to nonexercised mice, protein levels of caspase 3 (P < 0.001) and cytosolic cytochrome c (P < 0.005) were significantly elevated, whereas Bcl-2 (P < 0.05) was significantly lower immediately after exercise in mice receiving saline (EX + SAL + Imm) but not in animals receiving NAC (EX + NAC + Imm) or both 24 h postgroups (EX + SAL + 24 h and EX + NAC + 24 h). CONCLUSION: These results suggest that oxidative stress acting through a mitochondrial pathway may play a role in intestinal lymphocyte apoptosis after strenuous exercise.

Med Sci Sports Exerc. 2005 Jan;37(1):53-6

Exercise affects tissue lymphocyte apoptosis via redox-sensitive and Fas-dependent signaling pathways.

Intensive and exhaustive exercise induces an activation of blood T-lymphocytes, which seems to be terminated by apoptotic processes in the postexercise period. Here, we report that exercise-induced T-lymphocyte apoptosis is a systemic phenomenon occurring in various lymphoid and nonlymphoid tissues. The apoptosis rate could be related to exercise intensity and type. Although in some tissues, such as the spleen and Peyer’s patches, an early start of apoptosis (1-3 h postexercise) could be detected, a delayed apoptosis (24 h postexercise) was observed in lung, bone marrow, and lymph nodes. Further analysis showed a similar apoptosis distribution among lymphocyte subpopulations. We tested whether components of the extrinsic or the intrinsic apoptotic pathways or both were involved in these processes. Elevated levels of lipid peroxidation-product malondialdehyde (MDA), indicating an increased production of reactive oxygen species (ROS), were found after exercise in Peyer’s patches, lung, and spleen, but not in lymph nodes. Application of N-acetyl cysteine (NAC) prevented exercise-induced T-cell apoptosis completely in spleen and bone marrow, partially in lung and Peyer’s patches, while it was ineffective in lymph nodes. Additionally, exercise addressed the Fas-mediated apoptosis. The percentage of Fas-receptor (Fas+) and Fas-ligand positive (FasL+) lymphocytes was enhanced in Peyer’s patches after exercise. Moreover, FasL+ T cells were increased in the lung, while in lymph nodes Fas+ cells were increased. The critical role of Fas signaling in exercise-induced apoptosis was supported by using Fas-deficient MRL/lpr-mice. In Fas-deficient mice, exercise-induced T-lymphocyte apoptosis was prevented in spleen, lung, bone marrow, and lymph nodes, but not in Peyer’s patches. These data demonstrate that exercise-induced lymphocyte apoptosis is a transient systemic process with tissue-type specific apoptosis-inducing mechanisms, whose relevance for the adaptive immune competence remains to be shown.

Am J Physiol Regul Integr Comp Physiol. 2009 May;296(5):R1518-27

The molecular basis for oxidative stress-induced insulin resistance.

Reactive oxygen and nitrogen molecules have been typically viewed as the toxic by-products of metabolism. However, accumulating evidence has revealed that reactive species, including hydrogen peroxide, serve as signaling molecules that are involved in the regulation of cellular function. The chronic and/or increased production of these reactive molecules or a reduced capacity for their elimination, termed oxidative stress, can lead to abnormal changes in intracellular signaling and result in chronic inflammation and insulin resistance. Inflammation and oxidative stress have been linked to insulin resistance in vivo. Recent studies have found that this association is not restricted to insulin resistance in type 2 diabetes, but is also evident in obese, nondiabetic individuals, and in those patients with the metabolic syndrome. An increased concentration of reactive molecules triggers the activation of serine/threonine kinase cascades such as c-Jun N-terminal kinase, nuclear factor-kappaB, and others that in turn phosphorylate multiple targets, including the insulin receptor and the insulin receptor substrate (IRS) proteins. Increased serine phosphorylation of IRS reduces its ability to undergo tyrosine phosphorylation and may accelerate the degradation of IRS-1, offering an attractive explanation for the molecular basis of oxidative stress-induced insulin resistance. Consistent with this idea, studies with antioxidants such as vitamin E, alpha-lipoic acid, and N-acetyl cysteine indicate a beneficial impact on insulin sensitivity, and offer the possibility for new treatment approaches for insulin resistance.

Antioxid Redox Signal. 2005 Jul-Aug;7(7-8):1040-52

Aminoacid support in the prevention of diabetes and diabetic complications.

Emerging evidence suggests that amino acids may be potentially important in the prevention of diabetes and diabetes-associated complications. The pathways involved in the pathogenesis of diabetic complications include increased polyol pathway flux, increased advanced glycation end products formation, activation of protein kinase C and oxidative and carbonyl stress. This review will discuss the modulatory effects of amino acids on insulin secretion and their action in concert with insulin as signaling molecules. Evidences for the role of some amino acids in controlling glycemia and glucose-triggered pathological pathways are also included. Individual amino acids, especially the ones bestowed with antioxidant property like N-acetyl cysteine and taurine seem to have beneficial effects by their ability to reduce intracellular oxidative stress generation and glycooxidation. Other amino acids like glycine and lysine may be good candidates for the prevention of glycation. Nutritional intervention with taurine, phenyl alanine or branched chain amino acids can improve insulin sensitivity and post-prandial glucose disposal. Deficiency of one or more amino acids has been observed in diabetes and the beneficial effects of amino acids in some studies are positively correlated with the increase in plasma levels of these amino acids. Inclusion of individual amino acids/mixture, perhaps as a combinational therapy with conventional treatment protocols could be of therapeutic interest.

Curr Protein Pept Sci. 2009 Feb;10(1):8-17

Methylglyoxal contributes to the development of insulin resistance and salt sensitivity in Sprague-Dawley rats.

OBJECTIVES: Methylglyoxal, a metabolite of the glycolysis pathway, may play an important role in the development of diabetes and hypertension, but the exact mechanism has not been fully elucidated. The present study was designed to investigate whether methylglyoxal could directly induce insulin resistance and salt sensitivity in Sprague-Dawley rats. METHODS: Rats were allocated to four groups: control (normal drinking water), 1% methylglyoxal in drinking water, 1% methylglyoxal plus N-acetyl cysteine (NAC) (800 mg/kg per day), a methylglyoxal scavenger, or TM2002 (100 mg/kg per day), an advanced glycation endproducts (AGEs) inhibitor. After 4-week treatment insulin resistance was evaluated by an euglycemic hyperinsulinemic glucose clamp technique. In another set of rats, either a high-salt diet (4%) alone, standard rat chow with 1% methylglyoxal in drinking water or high-salt diet plus methylglyoxal was given for 4 weeks. Immunohistochemistry was performed to measure nitrotyrosine and methylglyoxal-induced AGEs, N-carboxyethyl-lysine (CEL) in the kidney. RESULTS: Four-week treatment with NAC or TM2002 completely improved methylglyoxal-induced insulin resistance. Co-administration of methylglyoxal and high-salt diet significantly increased systolic blood pressure, urinary albumin excretion, urinary thiobarbituric acid-reactive substances excretion and the renal nitrotyrosine expression in the kidney (markers of oxidative stress) compared with methylglyoxal or high-salt diet alone. Renal CEL was significantly increased in methylglyoxal-treated rats compared with nonmethylglyoxal-treated rats. CONCLUSION: These results indicate that methylglyoxal-induced insulin resistance and salt sensitivity at least in part by increasing oxidative stress and/or AGEs formation in Sprague-Dawley rats. The present study provides further evidence for methylglyoxal as one of the causative factors in the pathogenesis of insulin resistance and salt-sensitive hypertension.

J Hypertens. 2009 Aug;27(8):1664-71

Chronic N-acetyl cysteine prevents fructose-induced insulin resistance and hypertension in rats.

We examined if administration of an antioxidant compound protects against the development of insulin resistance and hypertension. Male rats were assigned randomly into four groups, and treated for 12 weeks with normal chow, normal chow plus N-acetyl cysteine (1.5 g/day/kg), fructose (60% of diet), and fructose plus N-acetyl cysteine. After 10 weeks, plasma triglyceride and 15-F2t-isoprostane, and insulin sensitivity were measured, and after 12 weeks, pressor response to methoxamine (15-60 microg/kg min) was assessed. Relative to normal chow-fed controls, the fructose-fed rats had increased blood pressure, plasma insulin, triglyceride and 15-F2t-isoprostane, and decreased insulin sensitivity; these changes were inhibited by N-acetyl cysteine. Maximal pressor response to methoxamine was attenuated in the fructose-fed rats given N-acetyl cysteine relative to the other three groups. Therefore, chronic treatment with N-acetyl cysteine increases insulin sensitivity and prevents the blood pressure increase associated with fructose feeding in rats, the mechanism may involve the decrease of oxidative stress and alpha-adrenoceptor-mediated vasoconstriction.

Eur J Pharmacol. 2005 Jan 31;508(1-3):205-10

Prolonged treatment with N-acetyl cysteine and L-arginine restores gonadal function in patients with polycystic ovary syndrome.

Nitric oxide (NO) plays a wide spectrum of biological actions including a positive role in oocyte maturation and ovulation. Free radicals levels have been shown elevated in polycystic ovary syndrome (PCOS) and therefore would be responsible for quenching NO that, in turn, would play a role in determining oligo- or amenorrhea connoting PCOS. Eight patients with PCOS displaying oligo-amenorrhea from at least 1 yr underwent a combined treatment with N-acetyl cysteine (NAC) (1200 mg/die) plus L-arginine (ARG) (1600 mg/die) for 6 months. Menstrual function, glucose and insulin levels, and, in turn, homeostasis model assessment (HOMA) index were monitored. Menstrual function was at some extent restored as indicated by the number of uterine bleedings under treatment (3.00, 0.18-5.83 vs 0.00, 0.00-0.83; p<0.02). Also, a well-defined biphasic pattern in the basal body temperature suggested ovulatory cycles. The HOMA index decreased under treatment (2.12, 1.46-4.42 vs 3.48, 1.62-5.95; p<0.05). In conclusion, this preliminary, open study suggests that prolonged treatment with NAC+ARG might restore gonadal function in PCOS. This effect seems associated to an improvement in insulin sensitivity.

J Endocrinol Invest. 2009 Dec;32(11):870-2

N-acetyl cysteine treatment improves insulin sensitivity in women with polycystic ovary syndrome.

OBJECTIVE: To evaluate the effect of N-acetyl cysteine (NAC) on insulin secretion and peripheral insulin resistance in subjects with polycystic ovary syndrome (PCOS). DESIGN: Prospective data analysis. SETTING: Volunteer women in an academic research environment. PATIENT(S): Six lean and 31 obese subjects, aged 19-33 years. INTERVENTION(S): Patients were treated for 5-6 weeks with NAC at a dose of 1.8 g/day orally. A dose of 3 g/day was arbitrarily chosen for massively obese subjects. Six of 31 obese patients with PCOS were treated with placebo and served as controls. MAIN OUTCOME MEASURE(S): Before and after the treatment period, the hormonal and lipid blood profile and insulin sensitivity, assessed by an hyperinsulinemic euglycemic clamp, were evaluated and an oral glucose tolerance test (OGTT) was performed. RESULT(S): Fasting glucose, fasting insulin, and glucose area under curve (AUC) were unchanged after treatment. Insulin AUC after OGTT was significantly reduced, and the peripheral insulin sensitivity increased after NAC administration, whereas the hepatic insulin extraction was unaffected. The NAC treatment induced a significant fall in T levels and in free androgen index values (P<.05). In analyzing patients according to their insulinemic response to OGTT, normoinsulinemic subjects and placebo-treated patients did not show any modification of the above parameters, whereas a significant improvement was observed in hyperinsulinemic subjects. CONCLUSION(S): NAC may be a new treatment for the improvement of insulin circulating levels and insulin sensitivity in hyperinsulinemic patients with polycystic ovary syndrome.

Fertil Steril. 2002 Jun;77(6):1128-35

N-acetyl cysteine and penicillamine induce apoptosis via the ER stress response-signaling pathway.

N-acetyl cysteine (NAC) and penicillamine (PEN) have been shown to induce apoptosis in multiple types of human cancer cells; however, the molecular mechanism underlying this activity is unclear. This study was designed to identify the genes responsible for apoptosis induction by NAC and PEN. We found that glucose-regulated protein 78 (GRP78) was upregulated in HeLa cells following treatment with NAC or PEN. GRP78 is a central regulator of endoplasmic reticulum (ER) stress and has been used as a marker of ER stress. Additionally, both the activating transcription factor 6 (ATF6) protein and X box-binding protein 1 (XBP1) mRNA were processed, which facilitates the expression of C/EBP homologous protein (CHOP), a key-signaling component of ER stress-induced apoptosis. Furthermore, the PERK-ATF4 pathway, which also induces the expression of CHOP, was activated in NAC-treated cells. The role of the ER stress pathway was further confirmed through the small interfering RNA (siRNA)-mediated knockdown of CHOP, which attenuated NAC and PEN-induced apoptosis. These results demonstrate that NAC- and PEN-induced apoptosis in HeLa cells is mediated by the ER stress pathway.

Mol Carcinog. 2010 Jan;49(1):68-74

N-acetyl cysteine inhibits human signet ring cell gastric cancer cell line (SJ-89) cell growth by inducing apoptosis and DNA synthesis arrest.

BACKGROUND AND AIMS: In this study, we investigated the inhibitory effects of N-acetyl cysteine (NAC) on the growth of the human signet ring cell from the gastric-cancer cell line SJ-89 , via the induction of apoptosis and the arrest of DNA synthesis. MATERIALS AND METHODS: SJ-89 cells were regularly incubated in the presence of NAC at 5, 10 and 20 mmol/l, and with IMDM as untreated control. Trypan blue-dye exclusion analysis and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide assay were applied to detect cell proliferation. Apoptotic morphology was observed by electron microscopy. Flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling (TUNEL) assay were performed to detect NAC-triggered apoptosis. RESULTS: NAC could inhibit proliferation of human gastric cancer SJ-89 cells in a dose-dependent and time-dependent manner. The growth curve showed suppression by 15.8, 37.6, and 66.3% following 72 h of NAC treatment at 5, 10 and 20 mmol/l, respectively, similar to the findings of 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide assay. DNA synthesis was evidently reduced by 25, 39, and 91% after 24 h NAC treated at 20 mmol/l and 5 days at 10 and 20 mmol/l, respectively. Cell growth was inhibited by 100% with the treatment of 20 mmol/l NAC on day 6. NAC-treated SJ-89 cells were characterized by typical apoptotic alterations, including morphological changes by electron microscopy, typical apoptotic sub-G1 peaking observed by flow cytometry and increase of apoptotic cells with the elevation of the concentration of NAC in a clearly dose-dependent manner by TUNEL assay. Electrophoresis analysis showed typical ‘DNA ladder’. CONCLUSION: The data above implicated that NAC inhibits human gastric-cancer SJ-89 cell growth by inducing apoptosis and DNA synthesis arrest. Although the exact mechanisms involved in NAC-induced apoptosis have not been known up to now, the ability to induce apoptosis in a tumor-cell population within 48 h is worth noting. It is also noteworthy that NAC can selectively inhibit the growth of tumor cells. Further studies are needed to elucidate the mechanisms.

Eur J Gastroenterol Hepatol. 2007 Sep;19(9):769-74

Antioxidants tiron and N-acetyl cysteine differentially mediate apoptosis in melanoma cells via a reactive oxygen species-independent NF-kappaB pathway.

Tiron and N-acetyl cysteine (NAC) have been recognized as potential antioxidants capable of inhibiting apoptosis induced by reactive oxygen species (ROS). Although the ROS-scavenging function of tiron and NAC is clear, the mechanism for their regulation of apoptosis is still elusive. Here we demonstrate that tiron increases nuclear factor-kappaB (NF-kappaB)/DNA binding and as a result enhances NF-kappaB transcriptional activity. In contrast, NAC inhibits NF-kappaB activation by reducing inhibitor of kappaB kinase (IKK) activity. Moreover, the expression of an NF-kappaB target gene, the chemokine CXCL1, is promoted by tiron and suppressed by NAC. Finally, tiron confers an antiapoptotic function, while NAC imparts a proapoptotic function in melanoma cells. These functions correlate with the alteration of mitochondrial membrane potential but not ROS production or induction of activating protein-1 (AP-1). This study underscores the potential benefits of regulating NF-kappaB activity in melanoma cells as a therapeutic approach.

Free Radic Biol Med. 2007 May 1;42(9):1369-80

N-acetyl cysteine fosters inactivation and transfer to endolysosomes of c-Src.

The non-receptor-protein tyrosine kinase c-Src is overexpressed and activated in a large number of human cancers, in which it is associated with tumor development and progression. Canonical regulation takes place by means of an alternative phosphorylation of tyrosine residues—Tyr419 for activation and Tyr530 for inactivation. An independent redox regulation mechanism, involving cysteine residues, has also been proposed, in which oxidation activates the enzyme. Here we present a kinetic analysis of the effect of N-acetyl cysteine (NAC) on c-Src, demonstrating that reduction reverts the oxidation-driven activation. In cancer cells, we show that NAC treatment produces an increase in specifically labeled reduced thiols of c-Src cysteines, thus confirming a redox transition. In addition to a decrease in Tyr419 phosphorylation, this leads to a massive shift of c-Src from plasma membranes—where its active form is located—to endolysosomal compartments. With the objective of deciphering the complex issue of c-Src regulation and of devising new strategies to revert its activation in cancers, redox regulation thus emerges as a promising area for study.

Free Radic Biol Med. 2008 Dec 1;45(11):1566-72

N-acetyl cysteine protects against ionizing radiation-induced DNA damage but not against cell killing in yeast and mammals.

Ionizing radiation (IR) induces DNA strand breaks leading to cell death or deleterious genome rearrangements. In the present study, we examined the role of N-acetyl cysteine (NAC), a clinically proven safe agent, for it’s ability to protect against gamma-ray-induced DNA strand breaks and/or DNA deletions in yeast and mammals. In the yeast Saccharomyces cerevisiae, DNA deletions were scored by reversion to histidine prototrophy. Human lymphoblastoid cells were examined for the frequency of gamma-H2AX foci formation, indicative of DNA double strand break formation. DNA strand breaks were also measured in mouse peripheral blood by the alkaline comet assay. In yeast, NAC reduced the frequency of IR-induced DNA deletions. However, NAC did not protect against cell death. NAC also reduced gamma-H2AX foci formation in human lymphoblastoid cells but had no protective effect in the colony survival assay. NAC administration via drinking water fully protected against DNA strand breaks in mice whole-body irradiated with 1Gy but not with 4Gy. NAC treatment in the absence of irradiation was not genotoxic. These data suggest that, given the safety and efficacy of NAC in humans, NAC may be useful in radiation therapy to prevent radiation-mediated genotoxicity, but does not interfere with efficient cancer cell killing.

Mutat Res. 2009 Jun 1;665(1-2):37-43

Prevention of cigarette smoke-induced lung tumors in mice by budesonide, phenethyl isothiocyanate, and N-acetyl cysteine.

Lung cancer is the most important cause of death among neoplastic diseases worldwide, and cigarette smoke (CS) is the major risk factor for cancer. Complementarily to avoidance of exposure to CS, chemoprevention will lower the risk of cancer in passive smokers, ex-smokers, and addicted current smokers who fail to quit smoking. Unfortunately, chemoprevention clinical trials have produced disappointing results to date and, until recently, a suitable animal model evaluating CS carcinogenicity was not available. We previously demonstrated that mainstream CS induces a potent carcinogenic response when exposure of mice starts at birth. In the present study, neonatal mice (strain H) were exposed to CS for 120 consecutive days, starting at birth. The chemopreventive agents budesonide (2.4 mg/kg diet), phenethyl isothiocyanate (PEITC, 1,000 mg/kg diet), and N-acetyl cysteine (NAC, 1,000 mg/kg body weight) were administered orally according to various protocols. The experiment was stopped after 210 days. Exposure to CS resulted in a high incidence and multiplicity of benign lung tumors and in significant increases of malignant lung tumors and other histopathological alterations. All three chemopreventive agents, administered to current smokers after weaning, were quite effective in protecting both male and female mice from CS pulmonary carcinogenicity. When given to ex-smokers after withdrawal of exposure to CS, the protective capacity of budesonide was unchanged, while PEITC lost part of its cancer chemopreventive activity. In conclusion, the proposed experimental model provides convincing evidence that it is possible to prevent CS-induced lung cancer by means of dietary and pharmacological agents.

Int J Cancer. 2010 Mar 1;126(5):1047-54

N-acetyl cysteine and S-methylcysteine inhibit MeIQx rat hepatocarcinogenesis in the post-initiation stage.

N-acetyl cysteine (NAC) and S-methylcysteine (SMC), water soluble organosulfur compounds contained in garlic, were evaluated for chemoprevention of hepatocarcinogenesis after 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) initiation in rats. Intergastric treatment with NAC or SMC five times a week resulted in decreased numbers and areas of preneoplastic, glutathione S-transferase placental form (GST-P) positive foci of the liver in a dose-dependent manner. Moreover, cell proliferation was reduced in GST-P positive foci by NAC and SMC. Insulin-like growth factor I (IGF-I) and inducible nitric oxide synthase (iNOS) mRNA expressions were found downregulated in the liver by NAC. The studies indicate that NAC can serve as a chemopreventive agent for rat hepatocarcinogenesis induced by MeIQx by reducing cell proliferation, which may involve IGF-I and iNOS downregulation.

Carcinogenesis. 2006 May;27(5):982-8

N-acetyl cysteine N-acetyl cysteine inhibits exercise-induced lymphocyte apoptotic protein alterations.

PURPOSE: To investigate the effect of strenuous exercise and antioxidant administration on pro- and antiapoptotic protein expression in intestinal lymphocytes. METHODS: Female C57BL/6 mice (N = 52) were randomly assigned to receive N-acetyl cysteine (NAC; 1 g.kg(-1)) or saline (SAL) 30 min before treadmill exercise (EX) for 90 min and 2 degrees slope (30 min at 22 m.min(-1), 30 min at 25 m.min(-1), and 30 min at 28 m.min(-1)) and sacrificed immediately (Imm) or 24 h (24 h) after exercise. Control mice were exposed to treadmill noise and vibration without running (nonexercised). Intestinal lymphocytes (IL) were isolated and pro- and antiapoptotic protein expression was evaluated by Western blot analysis. RESULTS: IL protein levels of proapoptotic (caspase 3 and cytosolic cytochrome c) and antiapoptotic (Bcl-2) were significantly different among groups. Relative to nonexercised mice, protein levels of caspase 3 (P < 0.001) and cytosolic cytochrome c (P < 0.005) were significantly elevated, whereas Bcl-2 (P < 0.05) was significantly lower immediately after exercise in mice receiving saline (EX + SAL + Imm) but not in animals receiving NAC (EX + NAC + Imm) or both 24 h postgroups (EX + SAL + 24 h and EX + NAC + 24 h). CONCLUSION: These results suggest that oxidative stress acting through a mitochondrial pathway may play a role in intestinal lymphocyte apoptosis after strenuous exercise.

Med Sci Sports Exerc. 2005 Jan;37(1):53-6

Exercise affects tissue lymphocyte apoptosis via redox-sensitive and Fas-dependent signaling pathways.

Intensive and exhaustive exercise induces an activation of blood T-lymphocytes, which seems to be terminated by apoptotic processes in the postexercise period. Here, we report that exercise-induced T-lymphocyte apoptosis is a systemic phenomenon occurring in various lymphoid and nonlymphoid tissues. The apoptosis rate could be related to exercise intensity and type. Although in some tissues, such as the spleen and Peyer’s patches, an early start of apoptosis (1-3 h postexercise) could be detected, a delayed apoptosis (24 h postexercise) was observed in lung, bone marrow, and lymph nodes. Further analysis showed a similar apoptosis distribution among lymphocyte subpopulations. We tested whether components of the extrinsic or the intrinsic apoptotic pathways or both were involved in these processes. Elevated levels of lipid peroxidation-product malondialdehyde (MDA), indicating an increased production of reactive oxygen species (ROS), were found after exercise in Peyer’s patches, lung, and spleen, but not in lymph nodes. Application of N-acetyl cysteine (NAC) prevented exercise-induced T-cell apoptosis completely in spleen and bone marrow, partially in lung and Peyer’s patches, while it was ineffective in lymph nodes. Additionally, exercise addressed the Fas-mediated apoptosis. The percentage of Fas-receptor (Fas+) and Fas-ligand positive (FasL+) lymphocytes was enhanced in Peyer’s patches after exercise. Moreover, FasL+ T cells were increased in the lung, while in lymph nodes Fas+ cells were increased. The critical role of Fas signaling in exercise-induced apoptosis was supported by using Fas-deficient MRL/lpr-mice. In Fas-deficient mice, exercise-induced T-lymphocyte apoptosis was prevented in spleen, lung, bone marrow, and lymph nodes, but not in Peyer’s patches. These data demonstrate that exercise-induced lymphocyte apoptosis is a transient systemic process with tissue-type specific apoptosis-inducing mechanisms, whose relevance for the adaptive immune competence remains to be shown.

Am J Physiol Regul Integr Comp Physiol. 2009 May;296(5):R1518-27

The molecular basis for oxidative stress-induced insulin resistance.

Reactive oxygen and nitrogen molecules have been typically viewed as the toxic by-products of metabolism. However, accumulating evidence has revealed that reactive species, including hydrogen peroxide, serve as signaling molecules that are involved in the regulation of cellular function. The chronic and/or increased production of these reactive molecules or a reduced capacity for their elimination, termed oxidative stress, can lead to abnormal changes in intracellular signaling and result in chronic inflammation and insulin resistance. Inflammation and oxidative stress have been linked to insulin resistance in vivo. Recent studies have found that this association is not restricted to insulin resistance in type 2 diabetes, but is also evident in obese, nondiabetic individuals, and in those patients with the metabolic syndrome. An increased concentration of reactive molecules triggers the activation of serine/threonine kinase cascades such as c-Jun N-terminal kinase, nuclear factor-kappaB, and others that in turn phosphorylate multiple targets, including the insulin receptor and the insulin receptor substrate (IRS) proteins. Increased serine phosphorylation of IRS reduces its ability to undergo tyrosine phosphorylation and may accelerate the degradation of IRS-1, offering an attractive explanation for the molecular basis of oxidative stress-induced insulin resistance. Consistent with this idea, studies with antioxidants such as vitamin E, alpha-lipoic acid, and N-acetyl cysteine indicate a beneficial impact on insulin sensitivity, and offer the possibility for new treatment approaches for insulin resistance.

Antioxid Redox Signal. 2005 Jul-Aug;7(7-8):1040-52

Aminoacid support in the prevention of diabetes and diabetic complications.

Emerging evidence suggests that amino acids may be potentially important in the prevention of diabetes and diabetes-associated complications. The pathways involved in the pathogenesis of diabetic complications include increased polyol pathway flux, increased advanced glycation end products formation, activation of protein kinase C and oxidative and carbonyl stress. This review will discuss the modulatory effects of amino acids on insulin secretion and their action in concert with insulin as signaling molecules. Evidences for the role of some amino acids in controlling glycemia and glucose-triggered pathological pathways are also included. Individual amino acids, especially the ones bestowed with antioxidant property like N-acetyl cysteine and taurine seem to have beneficial effects by their ability to reduce intracellular oxidative stress generation and glycooxidation. Other amino acids like glycine and lysine may be good candidates for the prevention of glycation. Nutritional intervention with taurine, phenyl alanine or branched chain amino acids can improve insulin sensitivity and post-prandial glucose disposal. Deficiency of one or more amino acids has been observed in diabetes and the beneficial effects of amino acids in some studies are positively correlated with the increase in plasma levels of these amino acids. Inclusion of individual amino acids/mixture, perhaps as a combinational therapy with conventional treatment protocols could be of therapeutic interest.

Curr Protein Pept Sci. 2009 Feb;10(1):8-17

Methylglyoxal contributes to the development of insulin resistance and salt sensitivity in Sprague-Dawley rats.

OBJECTIVES: Methylglyoxal, a metabolite of the glycolysis pathway, may play an important role in the development of diabetes and hypertension, but the exact mechanism has not been fully elucidated. The present study was designed to investigate whether methylglyoxal could directly induce insulin resistance and salt sensitivity in Sprague-Dawley rats. METHODS: Rats were allocated to four groups: control (normal drinking water), 1% methylglyoxal in drinking water, 1% methylglyoxal plus N-acetyl cysteine (NAC) (800 mg/kg per day), a methylglyoxal scavenger, or TM2002 (100 mg/kg per day), an advanced glycation endproducts (AGEs) inhibitor. After 4-week treatment insulin resistance was evaluated by an euglycemic hyperinsulinemic glucose clamp technique. In another set of rats, either a high-salt diet (4%) alone, standard rat chow with 1% methylglyoxal in drinking water or high-salt diet plus methylglyoxal was given for 4 weeks. Immunohistochemistry was performed to measure nitrotyrosine and methylglyoxal-induced AGEs, N-carboxyethyl-lysine (CEL) in the kidney. RESULTS: Four-week treatment with NAC or TM2002 completely improved methylglyoxal-induced insulin resistance. Co-administration of methylglyoxal and high-salt diet significantly increased systolic blood pressure, urinary albumin excretion, urinary thiobarbituric acid-reactive substances excretion and the renal nitrotyrosine expression in the kidney (markers of oxidative stress) compared with methylglyoxal or high-salt diet alone. Renal CEL was significantly increased in methylglyoxal-treated rats compared with nonmethylglyoxal-treated rats. CONCLUSION: These results indicate that methylglyoxal-induced insulin resistance and salt sensitivity at least in part by increasing oxidative stress and/or AGEs formation in Sprague-Dawley rats. The present study provides further evidence for methylglyoxal as one of the causative factors in the pathogenesis of insulin resistance and salt-sensitive hypertension.

J Hypertens. 2009 Aug;27(8):1664-71

Chronic N-acetyl cysteine prevents fructose-induced insulin resistance and hypertension in rats.

We examined if administration of an antioxidant compound protects against the development of insulin resistance and hypertension. Male rats were assigned randomly into four groups, and treated for 12 weeks with normal chow, normal chow plus N-acetyl cysteine (1.5 g/day/kg), fructose (60% of diet), and fructose plus N-acetyl cysteine. After 10 weeks, plasma triglyceride and 15-F2t-isoprostane, and insulin sensitivity were measured, and after 12 weeks, pressor response to methoxamine (15-60 microg/kg min) was assessed. Relative to normal chow-fed controls, the fructose-fed rats had increased blood pressure, plasma insulin, triglyceride and 15-F2t-isoprostane, and decreased insulin sensitivity; these changes were inhibited by N-acetyl cysteine. Maximal pressor response to methoxamine was attenuated in the fructose-fed rats given N-acetyl cysteine relative to the other three groups. Therefore, chronic treatment with N-acetyl cysteine increases insulin sensitivity and prevents the blood pressure increase associated with fructose feeding in rats, the mechanism may involve the decrease of oxidative stress and alpha-adrenoceptor-mediated vasoconstriction.

Eur J Pharmacol. 2005 Jan 31;508(1-3):205-10

Prolonged treatment with N-acetyl cysteine and L-arginine restores gonadal function in patients with polycystic ovary syndrome.

Nitric oxide (NO) plays a wide spectrum of biological actions including a positive role in oocyte maturation and ovulation. Free radicals levels have been shown elevated in polycystic ovary syndrome (PCOS) and therefore would be responsible for quenching NO that, in turn, would play a role in determining oligo- or amenorrhea connoting PCOS. Eight patients with PCOS displaying oligo-amenorrhea from at least 1 yr underwent a combined treatment with N-acetyl cysteine (NAC) (1200 mg/die) plus L-arginine (ARG) (1600 mg/die) for 6 months. Menstrual function, glucose and insulin levels, and, in turn, homeostasis model assessment (HOMA) index were monitored. Menstrual function was at some extent restored as indicated by the number of uterine bleedings under treatment (3.00, 0.18-5.83 vs 0.00, 0.00-0.83; p<0.02). Also, a well-defined biphasic pattern in the basal body temperature suggested ovulatory cycles. The HOMA index decreased under treatment (2.12, 1.46-4.42 vs 3.48, 1.62-5.95; p<0.05). In conclusion, this preliminary, open study suggests that prolonged treatment with NAC+ARG might restore gonadal function in PCOS. This effect seems associated to an improvement in insulin sensitivity.

J Endocrinol Invest. 2009 Dec;32(11):870-2

N-acetyl cysteine treatment improves insulin sensitivity in women with polycystic ovary syndrome.

OBJECTIVE: To evaluate the effect of N-acetyl cysteine (NAC) on insulin secretion and peripheral insulin resistance in subjects with polycystic ovary syndrome (PCOS). DESIGN: Prospective data analysis. SETTING: Volunteer women in an academic research environment. PATIENT(S): Six lean and 31 obese subjects, aged 19-33 years. INTERVENTION(S): Patients were treated for 5-6 weeks with NAC at a dose of 1.8 g/day orally. A dose of 3 g/day was arbitrarily chosen for massively obese subjects. Six of 31 obese patients with PCOS were treated with placebo and served as controls. MAIN OUTCOME MEASURE(S): Before and after the treatment period, the hormonal and lipid blood profile and insulin sensitivity, assessed by an hyperinsulinemic euglycemic clamp, were evaluated and an oral glucose tolerance test (OGTT) was performed. RESULT(S): Fasting glucose, fasting insulin, and glucose area under curve (AUC) were unchanged after treatment. Insulin AUC after OGTT was significantly reduced, and the peripheral insulin sensitivity increased after NAC administration, whereas the hepatic insulin extraction was unaffected. The NAC treatment induced a significant fall in T levels and in free androgen index values (P<.05). In analyzing patients according to their insulinemic response to OGTT, normoinsulinemic subjects and placebo-treated patients did not show any modification of the above parameters, whereas a significant improvement was observed in hyperinsulinemic subjects. CONCLUSION(S): NAC may be a new treatment for the improvement of insulin circulating levels and insulin sensitivity in hyperinsulinemic patients with polycystic ovary syndrome.

Fertil Steril. 2002 Jun;77(6):1128-35

N-acetyl cysteine and penicillamine induce apoptosis via the ER stress response-signaling pathway.

N-acetyl cysteine (NAC) and penicillamine (PEN) have been shown to induce apoptosis in multiple types of human cancer cells; however, the molecular mechanism underlying this activity is unclear. This study was designed to identify the genes responsible for apoptosis induction by NAC and PEN. We found that glucose-regulated protein 78 (GRP78) was upregulated in HeLa cells following treatment with NAC or PEN. GRP78 is a central regulator of endoplasmic reticulum (ER) stress and has been used as a marker of ER stress. Additionally, both the activating transcription factor 6 (ATF6) protein and X box-binding protein 1 (XBP1) mRNA were processed, which facilitates the expression of C/EBP homologous protein (CHOP), a key-signaling component of ER stress-induced apoptosis. Furthermore, the PERK-ATF4 pathway, which also induces the expression of CHOP, was activated in NAC-treated cells. The role of the ER stress pathway was further confirmed through the small interfering RNA (siRNA)-mediated knockdown of CHOP, which attenuated NAC and PEN-induced apoptosis. These results demonstrate that NAC- and PEN-induced apoptosis in HeLa cells is mediated by the ER stress pathway.

Mol Carcinog. 2010 Jan;49(1):68-74

N-acetyl cysteine inhibits human signet ring cell gastric cancer cell line (SJ-89) cell growth by inducing apoptosis and DNA synthesis arrest.

BACKGROUND AND AIMS: In this study, we investigated the inhibitory effects of N-acetyl cysteine (NAC) on the growth of the human signet ring cell from the gastric-cancer cell line SJ-89 , via the induction of apoptosis and the arrest of DNA synthesis. MATERIALS AND METHODS: SJ-89 cells were regularly incubated in the presence of NAC at 5, 10 and 20 mmol/l, and with IMDM as untreated control. Trypan blue-dye exclusion analysis and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide assay were applied to detect cell proliferation. Apoptotic morphology was observed by electron microscopy. Flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling (TUNEL) assay were performed to detect NAC-triggered apoptosis. RESULTS: NAC could inhibit proliferation of human gastric cancer SJ-89 cells in a dose-dependent and time-dependent manner. The growth curve showed suppression by 15.8, 37.6, and 66.3% following 72 h of NAC treatment at 5, 10 and 20 mmol/l, respectively, similar to the findings of 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide assay. DNA synthesis was evidently reduced by 25, 39, and 91% after 24 h NAC treated at 20 mmol/l and 5 days at 10 and 20 mmol/l, respectively. Cell growth was inhibited by 100% with the treatment of 20 mmol/l NAC on day 6. NAC-treated SJ-89 cells were characterized by typical apoptotic alterations, including morphological changes by electron microscopy, typical apoptotic sub-G1 peaking observed by flow cytometry and increase of apoptotic cells with the elevation of the concentration of NAC in a clearly dose-dependent manner by TUNEL assay. Electrophoresis analysis showed typical ‘DNA ladder’. CONCLUSION: The data above implicated that NAC inhibits human gastric-cancer SJ-89 cell growth by inducing apoptosis and DNA synthesis arrest. Although the exact mechanisms involved in NAC-induced apoptosis have not been known up to now, the ability to induce apoptosis in a tumor-cell population within 48 h is worth noting. It is also noteworthy that NAC can selectively inhibit the growth of tumor cells. Further studies are needed to elucidate the mechanisms.

Eur J Gastroenterol Hepatol. 2007 Sep;19(9):769-74

Antioxidants tiron and N-acetyl cysteine differentially mediate apoptosis in melanoma cells via a reactive oxygen species-independent NF-kappaB pathway.

Tiron and N-acetyl cysteine (NAC) have been recognized as potential antioxidants capable of inhibiting apoptosis induced by reactive oxygen species (ROS). Although the ROS-scavenging function of tiron and NAC is clear, the mechanism for their regulation of apoptosis is still elusive. Here we demonstrate that tiron increases nuclear factor-kappaB (NF-kappaB)/DNA binding and as a result enhances NF-kappaB transcriptional activity. In contrast, NAC inhibits NF-kappaB activation by reducing inhibitor of kappaB kinase (IKK) activity. Moreover, the expression of an NF-kappaB target gene, the chemokine CXCL1, is promoted by tiron and suppressed by NAC. Finally, tiron confers an antiapoptotic function, while NAC imparts a proapoptotic function in melanoma cells. These functions correlate with the alteration of mitochondrial membrane potential but not ROS production or induction of activating protein-1 (AP-1). This study underscores the potential benefits of regulating NF-kappaB activity in melanoma cells as a therapeutic approach.

Free Radic Biol Med. 2007 May 1;42(9):1369-80

N-acetyl cysteine fosters inactivation and transfer to endolysosomes of c-Src.

The non-receptor-protein tyrosine kinase c-Src is overexpressed and activated in a large number of human cancers, in which it is associated with tumor development and progression. Canonical regulation takes place by means of an alternative phosphorylation of tyrosine residues—Tyr419 for activation and Tyr530 for inactivation. An independent redox regulation mechanism, involving cysteine residues, has also been proposed, in which oxidation activates the enzyme. Here we present a kinetic analysis of the effect of N-acetyl cysteine (NAC) on c-Src, demonstrating that reduction reverts the oxidation-driven activation. In cancer cells, we show that NAC treatment produces an increase in specifically labeled reduced thiols of c-Src cysteines, thus confirming a redox transition. In addition to a decrease in Tyr419 phosphorylation, this leads to a massive shift of c-Src from plasma membranes—where its active form is located—to endolysosomal compartments. With the objective of deciphering the complex issue of c-Src regulation and of devising new strategies to revert its activation in cancers, redox regulation thus emerges as a promising area for study.

Free Radic Biol Med. 2008 Dec 1;45(11):1566-72

N-acetyl cysteine protects against ionizing radiation-induced DNA damage but not against cell killing in yeast and mammals.

Ionizing radiation (IR) induces DNA strand breaks leading to cell death or deleterious genome rearrangements. In the present study, we examined the role of N-acetyl cysteine (NAC), a clinically proven safe agent, for it’s ability to protect against gamma-ray-induced DNA strand breaks and/or DNA deletions in yeast and mammals. In the yeast Saccharomyces cerevisiae, DNA deletions were scored by reversion to histidine prototrophy. Human lymphoblastoid cells were examined for the frequency of gamma-H2AX foci formation, indicative of DNA double strand break formation. DNA strand breaks were also measured in mouse peripheral blood by the alkaline comet assay. In yeast, NAC reduced the frequency of IR-induced DNA deletions. However, NAC did not protect against cell death. NAC also reduced gamma-H2AX foci formation in human lymphoblastoid cells but had no protective effect in the colony survival assay. NAC administration via drinking water fully protected against DNA strand breaks in mice whole-body irradiated with 1Gy but not with 4Gy. NAC treatment in the absence of irradiation was not genotoxic. These data suggest that, given the safety and efficacy of NAC in humans, NAC may be useful in radiation therapy to prevent radiation-mediated genotoxicity, but does not interfere with efficient cancer cell killing.

Mutat Res. 2009 Jun 1;665(1-2):37-43

Prevention of cigarette smoke-induced lung tumors in mice by budesonide, phenethyl isothiocyanate, and N-acetyl cysteine.

Lung cancer is the most important cause of death among neoplastic diseases worldwide, and cigarette smoke (CS) is the major risk factor for cancer. Complementarily to avoidance of exposure to CS, chemoprevention will lower the risk of cancer in passive smokers, ex-smokers, and addicted current smokers who fail to quit smoking. Unfortunately, chemoprevention clinical trials have produced disappointing results to date and, until recently, a suitable animal model evaluating CS carcinogenicity was not available. We previously demonstrated that mainstream CS induces a potent carcinogenic response when exposure of mice starts at birth. In the present study, neonatal mice (strain H) were exposed to CS for 120 consecutive days, starting at birth. The chemopreventive agents budesonide (2.4 mg/kg diet), phenethyl isothiocyanate (PEITC, 1,000 mg/kg diet), and N-acetyl cysteine (NAC, 1,000 mg/kg body weight) were administered orally according to various protocols. The experiment was stopped after 210 days. Exposure to CS resulted in a high incidence and multiplicity of benign lung tumors and in significant increases of malignant lung tumors and other histopathological alterations. All three chemopreventive agents, administered to current smokers after weaning, were quite effective in protecting both male and female mice from CS pulmonary carcinogenicity. When given to ex-smokers after withdrawal of exposure to CS, the protective capacity of budesonide was unchanged, while PEITC lost part of its cancer chemopreventive activity. In conclusion, the proposed experimental model provides convincing evidence that it is possible to prevent CS-induced lung cancer by means of dietary and pharmacological agents.

Int J Cancer. 2010 Mar 1;126(5):1047-54

N-acetyl cysteine and S-methylcysteine inhibit MeIQx rat hepatocarcinogenesis in the post-initiation stage.

N-acetyl cysteine (NAC) and S-methylcysteine (SMC), water soluble organosulfur compounds contained in garlic, were evaluated for chemoprevention of hepatocarcinogenesis after 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) initiation in rats. Intergastric treatment with NAC or SMC five times a week resulted in decreased numbers and areas of preneoplastic, glutathione S-transferase placental form (GST-P) positive foci of the liver in a dose-dependent manner. Moreover, cell proliferation was reduced in GST-P positive foci by NAC and SMC. Insulin-like growth factor I (IGF-I) and inducible nitric oxide synthase (iNOS) mRNA expressions were found downregulated in the liver by NAC. The studies indicate that NAC can serve as a chemopreventive agent for rat hepatocarcinogenesis induced by MeIQx by reducing cell proliferation, which may involve IGF-I and iNOS downregulation.

Carcinogenesis. 2006 May;27(5):982-8

Immunomodulatory effects of zinc and DHEA on the Th-1 immune response in rats infected with Trypanosoma cruzi.

Chagas’ disease is considered the sixth most important neglected tropical disease worldwide. Considerable knowledge has been accumulated concerning the role of zinc on cellular immunity. The steroid hormone dehydroepiandrosterone (DHEA) is also known to modulate the immune system. The aims of this paper were to investigate a possible synchronization of their effects on cytokines and NO production and the resistance to Trypanosoma cruzi during the acute phase of infection. It was found that zinc, DHEA or zinc and DHEA supplementation enhanced the immune response, as evidenced by a significant reduction in parasitemia levels. Zinc and DHEA supplementation exerted additive effects on the immune response by elevation of macrophage counts, and by increasing concentrations of IFN-gamma and NO.

Immunobiology. 2009 Jul 4 [Epub ahead of print]

Dehydroepiandrosterone increases resistance to experimental infection by Trypanosoma cruzi.

Dehydroepiandrosterone (DHEA) enhances immune responses against a wide range of viral, bacterial, and parasitic pathogens. In a previous study, we reported that administration of DHEA significantly decreased the numbers of blood parasites in Trypanosoma cruzi experimental infection. The present study was undertaken to determine the effectiveness of DHEA in reducing the severity of acute phase T. cruzi infection of male and female Wistar rats. Animals were treated subcutaneously with 40 mg/kg body weight/day of DHEA. The concentration of nitric oxide (NO) was determined in spleen peritoneal cavity. Interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) were determined in the sera of uninfected and infected animals. DHEA treatment augments NO production for both sexes after in vitro LPS treatment for uninfected animals. Infection triggered enhanced NO levels although not significant. IL-2 and IFN-gamma were detectable in higher concentrations in treated and infected rats of both genders when compared to untreated controls. These data suggest that DHEA may have a potent immunoregulatory function that can affect the course of T. cruzi infection.

Vet Parasitol. 2008 May 31;153(3-4):238-43

The sex steroid precursor DHEA accelerates cutaneous wound healing via the estrogen receptors.

Age-related impaired wound healing states lead to substantial morbidity and cost, with treatment in the USA resulting in an expenditure of over $9 billion per annum. Dehydroepiandrosterone (DHEA) is a ubiquitous adrenal hormone with immunomodulatory properties whose levels decline significantly with advanced age in humans. Conversion of DHEA locally to downstream steroid hormones leads to estrogenic and/or androgenic effects which may be important in age-related skin homeostasis, and which would avoid systemic adverse effects related to estrogen. We report that systemic DHEA levels are strongly associated with protection against chronic venous ulceration in humans. DHEA accelerated impaired healing in an impaired healing model (mice rendered hypogonadal) associated with increased matrix deposition and dampens the exaggerated inflammatory response. Such effects were mediated by local conversion of DHEA to estrogen, acting through the estrogen receptor, and vitro studies suggest a direct effect on specific pro-inflammatory cytokine production by macrophages via mitogen activated kinase (MAP) and phosphatidylinositol 3 (PI3) kinase pathways. In addition, we show that local injection of DHEA accelerates impaired healing in an ageing mouse colony. We suggest that exogenous application of DHEA accelerates impaired wound repair, results which may be applicable to the prophylaxis and treatment of human impaired wound healing states.

Invest Dermatol. 2005 Nov;125(5):1053-62

Oral administration of dehydroepiandrosterone-sulfate (DHEAS) increases in vitro lymphocyte function and improves in vivo response of pigs to immunization against keyhole limpet hemocyanin (KLH) and ovalbumin.

The present study tested the hypothesis that the oral administration of DHEAS enhances the in vitro and the in vivo immune response of young pigs. Crossbred, female pigs (80 days of age; 49+/-2 kg) were separated into two treatment groups (n=4/treatment) receiving either 0mg/kg (control) or 1mg/kg DHEAS twice daily (DHEAS) for 5 weeks. On day 7 pigs were immunized against KLH and ovalbumin. Body weight increased weekly throughout the study but did not differ between treatment groups. While white blood cell counts increased in response to immunization but did not differ between treatments, the neutrophil:lymphocyte ratio was enhanced (P<0.05) in DHEAS-supplemented pigs. Concanavalin A (ConA) induced an in vitro dose-dependent increase (P<0.05) in lymphocyte proliferation, but treatment did not affect proliferation prior to immunization. However, lymphocytes isolated from DHEAS-supplemented pigs displayed a greater increase in proliferation following immunization relative to control pigs (P<0.05). Dexamethasone (DEX) attenuated ConA-induced lymphocyte proliferation, with DHEAS-supplemented pigs retaining a greater proliferative response relative to control pigs (P<0.05). Serum IgG concentrations and relative concentrations of antigen-specific IgG increased after immunization with maximum values attained at 21 and 28 days for control and DHEAS-supplemented pigs, respectively. The DHEAS-supplemented pigs had greater (P<0.05) concentrations of IgG and relative concentrations of antigen-specific IgG compared to control pigs. Collectively these data suggest DHEAS supplementation increases the responsiveness of young pigs to antigenic challenge, and may be beneficial for improving their immune function.

Int Immunopharmacol. 2009 Oct;9(11):1342-6

Dehydroepiandrosterone: a modulator of cellular immunity and heat shock protein 70 production during polymicrobial sepsis.

OBJECTIVE: DHEA is an immunomodulatory steroid hormone that improves survival during systemic inflammation. A DHEA-induced modulation of heat shock protein response may be an alternative mechanism contributing to the beneficial effects of this hormone. We investigated the effect of DHEA administration on survival, cellular immune functions, and HSP-70 production in septic mice. DESIGN AND SETTING: Randomized animal study, level I trauma center, university research laboratory. SUBJECTS: Male NMRI mice. INTERVENTIONS: Mice were subjected to sham operation (laparotomy, LAP) or sepsis (cecal ligation and puncture, CLP) with or without administration of either saline 0.9% (LAP, CLP) or 20 mg/kg DHEA subcutaneously (LAP/DHEA, CLP/DHEA). Survival was monitored over a 48-h period. Splenocyte apoptosis rate (AnnexinV binding), splenocyte proliferation ([3H]thymidine incorporation), TNF-alpha plasma concentration (ELISA), and HSP-70 concentration (ELISA) in tissue extracts from liver, lung, and spleen were monitored 48 h after onset of sepsis. RESULTS: DHEA administration improved the survival of septic mice (78% vs. 50%). This effect was paralleled by increased splenocyte proliferation, decreased cellular apoptosis rate of splenocytes, and attenuation of TNF-alpha release. Furthermore, an increased HSP-70 concentration was observed in lungs and spleens of DHEA-treated septic animals. CONCLUSIONS: DHEA-treatment decreased the mortality rate of septic mice. This was accompanied by improved cellular immune functions and an augmented heat shock response (HSP-70) of lungs and spleens. Further studies are required to demonstrate a direct relationship between the improved survival and the observed alterations in the immune system in DHEA-treated animals.

Intensive Care Med. 2007 Dec;33(12):2207-13

Mechanism of action of anti-aging DHEA-S and the replacement of DHEA-S.

The plasma ACTH and cortisol levels do not change during aging. On the other hand, the plasma dehydroepiandrosterone sulfate (DHEA-S) changes remarkably during aging. Before puberty, the plasma DHEA-S level both in males and females is very low, however, it rapidly increases at puberty, and thereafter significantly decreases both linearly and age-dependently. Cytochrome P450c17 has two enzyme activities, 17-alpha-hydroxylase and 17,20-lyase. Cortisol is synthesized by 17-alpha-hydroxylase, and DHEA is synthesized by 17,20-lyase. The mechanism of dissociation of cortisol and DHEA synthesis in aging depends on another regulator of 17,20-lyase of cytochrome P450c17 such as cytochrome P450 reductase. We demonstrated significant decrease in cytochrome P450 reductase activity in bovine aged adrenal glands. We clarified the beneficial effects of DHEA as an anti-aging steroid based on both in vitro and in vivo experiments, such as the stimulatory effect of immune system, anti-diabetes mellitus, anti-atherosclerosis, anti-dementia (neurosteroid), anti-obesity and anti-osteoporosis. It is very important to identify the mechanism of action of DHEA. We clarified the conversion of DHEA to estrone by cytochrome P450 aromatase in primary cultured human osteoblasts. We indentified high affinity of DHEA binding with K(d)=6.6 nM in antigen and DHEA stimulated human T lymphocytes. We searched for the target genes that are specifically induced in activated T lymphocytes in the presence of DHEA by subtractive hybridization screening for differentially expressed transcripts. The double blind, randomized human replacement therapies utilizing DHEA are also reviewed.

Mech Ageing Dev. 2002 Apr 30;123(8):1101-6

Impact of DHEA(S) and cortisol on immune function in aging: a brief review.

A decline in the human immune system that occurs with aging is known as immunosenescence. Several factors are involved in the process, including reduced neutrophil function and cytotoxic capacity of natural killer (NK) cells, thymus atrophy and reduced naïve T cell number, and lowered B cell antibody production in response to antigen. The endocrine system, specifically the hypothalamus-pituitary-adrenal axis, plays an important role in modulating immune function. With aging an imbalance occurs between two adrenal hormones, cortisol and DHEA, that have opposing actions on immune function. This brief review explores the interactions between cortisol and DHEA and their effects on immune function in aging, as well as potential methods to combat the endocrine-related contribution to immunosenescence, including DHEA supplementation and exercise.

Appl Physiol Nutr Metab. 2008 Jun;33(3):429-33

Dehydroepiandrosterone replacement therapy in older adults: 1- and 2-y effects on bone.

BACKGROUND: Age-related reductions in serum dehydroepiandrosterone (DHEA) concentrations may be involved in bone mineral density (BMD) losses. OBJECTIVE: The objective was to determine whether DHEA supplementation in older adults improves BMD when co-administered with vitamin D and calcium. DESIGN: In year 1, a randomized trial was conducted in which men (n = 55) and women (n = 58) aged 65-75 y took 50 mg/d oral DHEA supplements or placebo. In year 2, all participants took open-label DHEA (50 mg/d). During both years, all participants received vitamin D (16 microg/d) and calcium (700 mg/d) supplements. BMD was measured by using dual-energy X-ray absorptiometry. Concentrations of hormones and bone turnover markers were measured in serum. RESULTS: In men, no difference between groups occurred in any BMD measures or in bone turnover markers during year 1 or year 2. The free testosterone index and estradiol increased in the DHEA group only. In women, spine BMD increased by 1.7 +/- 0.6% (P = 0.0003) during year 1 and by 3.6 +/- 0.7% after 2 y of supplementation in the DHEA group; however, in the placebo group, spine BMD was unchanged during year 1 but increased to 2.6 +/- 0.9% above baseline during year 2 after the crossover to DHEA. Hip BMD did not change. Testosterone, estradiol, and insulin-like growth factor 1 increased in the DHEA group only. In both groups, serum concentrations of bone turnover markers decreased during year 1 and remained low during year 2, but did not differ between groups. CONCLUSION: DHEA supplementation in older women, but not in men, improves spine BMD when co-administered with vitamin D and calcium.

Am J Clin Nutr. 2009 May;89(5):1459-67

Effect of dehydroepiandrosterone supplementation on bone mineral density, bone markers, and body composition in older adults: the DAWN trial.

SUMMARY: We present results of a randomized, placebo-controlled trial to examine the effect of 50 mg daily oral DHEA supplementation for one year on bone mineral density (BMD), bone metabolism and body composition in 225 healthy adults aged 55 to 85 years. INTRODUCTION: Dehydroepiandrosterone (DHEA) levels decline dramatically with age, concurrent with the onset of osteoporosis, suggesting a role for DHEA supplementation in preventing age-related bone loss. METHODS: We conducted a randomized, placebo-controlled trial to examine the effect of 50 mg daily oral DHEA supplementation for one year on bone mineral density (BMD), bone metabolism and body composition in 225 healthy adults aged 55 to 85 years. RESULTS: DHEA treatment increased serum DHEA and DHEA sulfate levels to concentrations seen in young adults. Testosterone, estradiol and insulin-like growth factor (IGF-1) levels increased in women (all p < 0.001), but not men, receiving DHEA. Serum C-terminal telopeptide of type-1 collagen levels decreased in women (p = 0.03), but not men, whereas bone-specific alkaline phosphatase levels were not significantly altered in either sex. After 12 months, there was a positive effect of DHEA on lumbar spine BMD in women (p = 0.03), but no effect was observed for hip, femoral neck or total body BMD, and no significant changes were observed at any site among men. Body composition was not affected by DHEA treatment in either sex. CONCLUSION: Among older healthy adults, daily administration of 50 mg of DHEA has a modest and selective beneficial effect on BMD and bone resorption in women, but provides no bone benefit for men.

Osteoporos Int. 2008 May;19(5):699-707

Dehydroepiandrosterone (DHEA), DHEA sulfate, and aging: contribution of the DHEAge Study to a sociobiomedical issue.

The secretion and the blood levels of the adrenal steroid dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) decrease profoundly with age, and the question is posed whether administration of the steroid to compensate for the decline counteracts defects associated with aging. The commercial availability of DHEA outside the regular pharmaceutical-medical network in the United States creates a real public health problem that may be resolved only by appropriate long-term clinical trials in elderly men and women. Two hundred and eighty healthy individuals (women and men 60-79 years old) were given DHEA, 50 mg, or placebo, orally, daily for a year in a double-blind, placebo-controlled study. No potentially harmful accumulation of DHEAS and active steroids was recorded. Besides the reestablishment of a “young” concentration of DHEAS, a small increase of testosterone and estradiol was noted, particularly in women, and may be involved in the significantly demonstrated physiological-clinical manifestations here reported. Bone turnover improved selectively in women >70 years old, as assessed by the dual-energy x-ray absorptiometry (DEXA) technique and the decrease of osteoclastic activity. A significant increase in most libido parameters was also found in these older women. Improvement of the skin status was observed, particularly in women, in terms of hydration, epidermal thickness, sebum production, and pigmentation. A number of biological indices confirmed the lack of harmful consequences of this 50 mg/day DHEA administration over one year, also indicating that this kind of replacement therapy normalized some effects of aging, but does not create “supermen/women” (doping).

Proc Natl Acad Sci U S A. 2000 Apr 11;97(8):4279-84

Increases in bone mineral density in response to oral dehydroepiandrosterone replacement in older adults appear to be mediated by serum estrogens.

CONTEXT: The mechanisms by which dehydroepiandrosterone (DHEA) replacement increases bone mineral density (BMD) in older adults are not known. Objective: The aims were to determine the effects of DHEA therapy on changes in sex hormones and IGF-I and their associations with changes in BMD. DESIGN, SETTING, AND PARTICIPANTS: A randomized, double-blinded, placebo-controlled trial was conducted at an academic research institution. Participants were 58 women and 61 men, aged 60-88 yr, with low serum DHEA sulfate (DHEAS) levels. INTERVENTION: The intervention was oral DHEA 50 mg/d or placebo for 12 months. MAIN OUTCOME MEASURES: BMD and serum DHEAS, testosterone, estradiol (E(2)), estrone (E(1)), SHBG, IGF-I, and IGF binding protein 3 were measured before and after intervention. Free testosterone and estrogen (FEI) indices were calculated. RESULTS: The average changes in hip and spine BMD (DHEA vs. placebo) ranged from 1.1 to 1.6%. Compared with placebo, DHEA replacement increased serum DHEAS, testosterone, free testosterone index, E(1), E(2), FEI, and IGF-I (all P < 0.001) and decreased SHBG (P = 0.02) in women and, in men, increased DHEAS, E(1), FEI (all P < 0.001), and E(2) (P = 0.02) and decreased SHBG (P = 0.037). The changes in total and regional hip BMD were associated with 12-month E(2) (all P <or= 0.001) and FEI (all P <or= 0.013). The effects of DHEA treatment were eliminated by adjustment for 12-month E(2). CONCLUSIONS: The significant increases in hip BMD in older adults undergoing DHEA replacement were mediated primarily by increases in serum E(2) rather than direct effects of DHEAS.

J Clin Endocrinol Metab. 2008 Dec;93(12):4767-73

Pomegranate derived products for cancer chemoprevention.

Because treatment options for advanced metastasized cancers remain inadequate, developing effective approaches for the prevention of cancer has become an important goal to reduce cancer burden. One such strategy is through chemoprevention, preferably by the use of non-toxic dietary substances and botanical products. Pomegranate, used for centuries for its medicinal properties is now being recognized as a potential chemopreventive and anticancer agent. Increasing body of evidence has underscored the cancer preventive efficacy of pomegranate both in vitro and in vivo animal models. The emerging data provide new insights into the molecular framework needed to establish novel mechanism-based chemopreventive strategies for various human cancers.

Semin Cancer Biol. 2007 Oct;17(5):377-85

Ellagic acid, pomegranate and prostate cancer—a mini review.

There is currently a shifting focus towards finding natural compounds that may prevent or treat cancer, due to the problems that exist with current chemotherapeutic regimens. The fruit of the Punica granatum (pomegranate) contains hundreds of phytochemicals and pomegranate extracts have recently been shown to exhibit antioxidant properties, thought to be due to the action of ellagic acid, the main polyphenol in pomegranate. In this mini review the effects of pomegranate extracts and ellagic acid on the proliferation of prostate cancer cells and their future potential are discussed.

J Pharm Pharmacol. 2008 Feb;60(2):139-44

Polyphenol-rich pomegranate fruit extract (POMx) suppresses PMACI-induced expression of pro-inflammatory cytokines by inhibiting the activation of MAP Kinases and NF-kappaB in human KU812 cells.

ABSTRACT: BACKGROUND: Mast cells and basophils are multifunctional effector cells and contain plentiful secretary granules in their cytoplasm. These cell types are involved in several inflammatory and immune events and are known to produce an array of mediators including a broad spectrum of cytokines. Pomegranate fruit is rich in anthocyanins and hydrolysable tannins; a group of polyphenolic compounds shown to be potent antioxidant with anti-inflammatory activity. However, no studies have been undertaken to investigate whether a polyphenol-rich pomegranate fruit extract (POMx) inhibits the inflammatory activity of activated human mast cells and basophils. The aim of this study was to examine whether POMx modulates inflammatory reactions using human basophilic cell line KU812. METHODS: KU812 cells were stimulated with phorbol-12-myristate 13-acetate plus calcium inophore A23187 (PMACI). The inhibitory effect of POMx on pro-inflammatory cytokine gene expression and production by stimulated KU812 cells was measured by quantitative RT-PCR, and cytokine-specific ELISA assays, respectively. Western blotting was used to analyze the effect of POMx on the activation of mitogen-activated protein kinases (MAPKs), and the nuclear factor (NF)-kappaB in PMACI stimulated KU812 cells. Effect on the activity of NF-kappaB was determined using Luciferase reporter assay. Significance of differences from control values were analyzed by means of standard statistical methods. RESULTS: POMx significantly decreased PMACI stimulated inflammatory gene expression and production of interleukin (IL)-6 and IL-8 in KU812 cells. The inhibitory effect of POMx on the pro-inflammatory cytokines was MAPK subgroups c-jun N-terminal kinase (JNK)- and extracellular-regulated kinase (ERK) dependent. In addition, POMx suppressed the NF-kappaB activation induced by PMACI by inhibiting IkappaB-degradation in human basophil cells. POMx also suppressed the powerful induction of NF-kappaB promoter-mediated luciferase activity in transiently transfected KU812 cells. CONCLUSION: These novel pharmacological actions of POMx provide new suggestion that POMx or POMx-derived compounds may be of therapeutic use for the treatment of inflammatory diseases by suppressing mast cells/basophils activation.

J Inflamm (Lond). 2009 Jan 8;6:1

Pomegranate extract inhibits androgen-independent prostate cancer growth through a nuclear factor-kappaB-dependent mechanism.

Constitutive nuclear factor-kappaB (NF-kappaB) activation is observed in androgen-independent prostate cancer and represents a predictor for biochemical recurrence after radical prostatectomy. Dietary agents such as pomegranate extract (PE) have received increasing attention as potential agents to prevent the onset or progression of many malignancies, including prostate cancer. Here, we show that PE inhibited NF-kappaB and cell viability of prostate cancer cell lines in a dose-dependent fashion in vitro. Importantly, maximal PE-induced apoptosis was dependent on PE-mediated NF-kappaB blockade. In the LAPC4 xenograft model, PE delayed the emergence of LAPC4 androgen-independent xenografts in castrated mice through an inhibition of proliferation and induction of apoptosis. Moreover, the observed increase in NF-kappaB activity during the transition from androgen dependence to androgen independence in the LAPC4 xenograft model was abrogated by PE. Our study represents the first description of PE as a promising dietary agent for the prevention of the emergence of androgen independence that is driven in part by heightened NF-kappaB activity.

Mol Cancer Ther. 2008 Sep;7(9):2662-71

Anti-Listeria monocytogenes activity of heat-treated lyophilized pomegranate juice in media and in ground top round beef.

Heat treatment can affect antimicrobial activity of plant by-products by altering phenolic content and composition and forming melanoidins. The antilisterial efficacy of heat-treated and unheated lyophilized pomegranate juice (LPJ) was determined. The LPJ was heated at 100 degrees C for 0, 30, 60, or 120 min and added at 2% (wt/wt) to ground top round beef, which was then cooked and inoculated with individual L. monocytogenes strains. Samples of meat stored at 5 degrees C were taken at days 1, 8, 14, and 21 and plated onto Oxford medium for enumeration of bacteria. The MIC of LPJ was determined, and agar well diffusion assays were conducted. Against five L. monocytogenes strains, LPJ had a MIC of 1.50 to 1.75% (wt/vol) and 16.8- to 20.0-mm zones of inhibition. In general, no significant differences in L. monocytogenes levels between the various treatments, including the commercial sodium lactate-sodium diacetate combination, were detected at days 1 and 8. The LPJ (0, 30, 60, and 120 min of heating) significantly inhibited growth of all five L. monocytogenes strains in refrigerated ground cooked beef by 1.80 to 4.61 log CFU/g at day 21. Heating did not negatively impact LPJ antilisterial activity. Addition of LPJ lowered pH values by 0.3 units. The L*, a*, and b* values of cooked ground beef with LPJ changed during the study by 3.4 to 4.43, 0.44 to 0.8, and 0.57 to 1.36 units, respectively, compared with the control. This is the first investigation to confirm pomegranate’s antilisterial activity in vitro and in ground beef.

J Food Prot. 2009 Dec;72(12):2508-16

Pomegranate flower improves cardiac lipid metabolism in a diabetic rat model: role of lowering circulating lipids.

Excess triglyceride (TG) accumulation and increased fatty acid (FA) oxidation in the diabetic heart contribute to cardiac dysfunction. Punica granatum flower (PGF) is a traditional antidiabetic medicine. Here, we investigated the effects and mechanisms of action of PGF extract on abnormal cardiac lipid metabolism both in vivo and in vitro. Long-term oral administration of PGF extract (500 mg kg(-1)) reduced cardiac TG content, accompanied by a decrease in plasma levels of TG and total cholesterol in Zucker diabetic fatty (ZDF) rats, indicating improvement by PGF extract of abnormal cardiac TG accumulation and hyperlipidemia in this diabetic model. Treatment of ZDF rats with PGF extract lowered plasma FA levels. Furthermore, the treatment suppressed cardiac overexpression of mRNAs encoding for FA transport protein, peroxisome proliferator-activated receptor (PPAR)-alpha, carnitine palmitoyltransferase-1, acyl-CoA oxidase and 5’-AMP-activated protein kinase alpha2, and restored downregulated cardiac acetyl-CoA carboxylase mRNA expression in ZDF rats, whereas it showed little effect in Zucker lean rats. The results suggest that PGF extract inhibits increased cardiac FA uptake and oxidation in the diabetic condition. PGF extract and its component oleanolic acid enhanced PPAR-alpha luciferase reporter gene activity in human embryonic kidney 293 cells, and this effect was completely suppressed by a selective PPAR-alpha antagonist MK-886, consistent with the presence of PPAR-alpha activator activity in the extract and this component. Our findings suggest that PGF extract improves abnormal cardiac lipid metabolism in ZDF rats by activating PPAR-alpha and thereby lowering circulating lipid and inhibiting its cardiac uptake.

Br J Pharmacol. 2005 Jul;145(6):767-74

Pomegranate flower: a unique traditional antidiabetic medicine with dual PPAR-alpha/-gamma activator properties.

PPARs are transcription factors belonging to the superfamily of nuclear receptors. PPAR-alpha is involved in the regulation of fatty acid (FA) uptake and oxidation, inflammation and vascular function, while PPAR-gamma participates in FA uptake and storage, glucose homeostasis and inflammation. The PPARs are thus major regulators of lipid and glucose metabolism. Synthetic PPAR-alpha or PPAR-gamma agonists have been widely used in the treatment of dyslipidaemia, hyperglycaemia and their complications. However, they are associated with an incidence of adverse events. Given the favourable metabolic effects of both PPAR-alpha and PPAR-gamma activators, as well as their potential to modulate vascular disease, combined PPAR-alpha/-gamma activation has recently emerged as a promising concept, leading to the development of mixed PPAR-alpha/-gamma activators. However, some major side effects associated with the synthetic dual activators have been reported. It is unclear whether this is a specific effect of the particular synthetic compounds or a class effect. To date, a medication that may combine the beneficial metabolic effects of PPAR-alpha and PPAR-gamma activation with fewer undesirable side effects has not been successfully developed. Pomegranate plant parts are used traditionally for the treatment of various disorders. However, only pomegranate flower has been prescribed in Unani and Ayurvedic medicines for the treatment of diabetes. This review provides a new understanding of the dual PPAR-alpha/-gamma activator properties of pomegranate flower in the potential treatment of diabetes and its associated complications.

Diabetes Obes Metab. 2008 Jan;10(1):10-7

Pomegranate flower extract diminishes cardiac fibrosis in Zucker diabetic fatty rats: modulation of cardiac endothelin-1 and nuclear factor-kappaB pathways.

The diabetic heart shows increased fibrosis, which impairs cardiac function. Endothelin (ET)-1 and nuclear factor-kappaB (NF-kappaB) interactively regulate fibroblast growth. We have recently demonstrated that Punica granatum flower (PGF), a Unani anti-diabetic medicine, is a dual activator of peroxisome proliferator-activated receptor (PPAR)-alpha and -gamma, and improves hyperglycemia, hyperlipidemia, and fatty heart in Zucker diabetic fatty (ZDF) rat, a genetic animal model of type 2 diabetes and obesity. Here, we demonstrated that six-week treatment with PGF extract (500 mg/kg, p.o.) in Zucker diabetic fatty rats reduced the ratios of van Gieson-stained interstitial collagen deposit area to total left ventricular area and perivascular collagen deposit areas to coronary artery media area in the heart. This was accompanied by suppression of overexpressed cardiac fibronectin and collagen I and III mRNAs. Punica granatum flower extract reduced the up-regulated cardiac mRNA expression of ET-1, ETA, inhibitor-kappaBbeta and c-jun, and normalized the down-regulated mRNA expression of inhibitor-kappaBalpha in Zucker diabetic fatty rats. In vitro, Punica granatum flower extract and its components oleanolic acid, ursolic acid, and gallic acid inhibited lipopolysaccharide-induced NF-kappaB activation in macrophages. Our findings indicate that Punica granatum flower extract diminishes cardiac fibrosis in Zucker diabetic fatty rats, at least in part, by modulating cardiac ET-1 and NF-kappaB signaling.

J Cardiovasc Pharmacol. 2005 Dec;46(6):856-62

Macrophage paraoxonase 2 (PON2) expression is up-regulated by pomegranate juice phenolic anti-oxidants via PPAR gamma and AP-1 pathway activation.

Paraoxonase 2 (PON2), a member of the paraoxonase gene family, was shown to protect macrophages against oxidative stress. Pomegranate juice (PJ), which contains potent polyphenol anti-oxidants, exhibits similar effects. We questioned possible association between PJ polyphenolics, macrophage oxidative stress, and cellular PON2 expression, in relation to the activation of specific PON2 transcription factors. Incubation of J774A.1 macrophages with PJ (0-50 microM of total polyphenols) dose-dependently increased expression (mRNA, protein) and activity and reduced macrophage oxidative status. These effects could be attributed to the PJ unique polyphenols, punicalagin and gallic acid. PJ polyphenol-induced up-regulation of PON2 was inhibited by 40% upon using the PPAR gamma inhibitor GW9662 (50 microM). Accordingly, the PPAR gamma ligand, rosiglitazone, dose-dependently stimulated macrophage PON2 expression, by up to 80%. Inhibition of AP-1 activation with SP600125, attenuated PJ-induced up-regulation of PON2 by 40%. Similarly, incubation of macrophages with PJ polyphenols in the presence of GW9662 or SP600125, significantly reduced their capacity to protect the cells against oxidative stress. We conclude that the anti-oxidative characteristics of PJ unique phenolics punicalagin and gallic acid could be related, at least in part, to their stimulatory effect on macrophage PON2 expression, a phenomenon which was shown to be associated with activation of the transcription factors PAPR gamma and AP-1.

Atherosclerosis. 2007 Dec;195(2):313-21

Pomegranate flower ameliorates fatty liver in an animal model of type 2 diabetes and obesity.

AIMS OF THE STUDY: Fatty liver is the most common cause of abnormal liver function tests. We investigated the effect and its underlying mechanism of pomegranate flower (PGF), a traditional antidiabetic medicine, on fatty liver. MATERIALS AND METHODS: At the endpoint of treatment of male Zucker diabetic fatty (ZDF) rats with PGF extract (500 mg/kg, p.o. x 6 weeks), liver weight index, hepatic lipid contents (enzymatic colorimetric methods) and droplet accumulation (Oil Red O staining) were determined. Gene profiles (RT-PCR) were analyzed in the liver of ZDF rats and in human liver-derived HepG2 cell line. RESULTS: PGF-treated ZDF rats showed reduced ratio of liver weight to tibia length, hepatic triglyceride contents and lipid droplets. These effects were accompanied by enhanced hepatic gene expression of peroxisome proliferator-activated receptor (PPAR)-alpha, carnitine palmitoyltransferase-1 and acyl-CoA oxidase (ACO), and reduced stearoyl-CoA desaturase-1. In contrast, PGF showed minimal effects on expression of genes responsible for synthesis, hydrolysis or uptake of fatty acid and triglycerides. PGF treatment also increased PPAR-alpha and ACO mRNA levels in HepG2 cells. CONCLUSION: Our findings suggest that this Unani medicine ameliorates diabetes and obesity-associated fatty liver, at least in part, by activating hepatic expression of genes responsible for fatty acid oxidation.

J Ethnopharmacol. 2009 Jun 22;123(2):280-7

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