Life Extension Magazine®

Issue: Jun 2015

Acid Reflux, Glycation, Mediterranean Trim, and Oxidized LDL

Acid Reflux, Glycation, Mediterranean Trim, and Oxidized LDL

By Life Extension.

Effect of esomeprazole 40 mg vs omeprazole 40 mg on 24-hour intragastric pH in patients with symptoms of gastroesophageal reflux disease.

Maintenance of intragastric pH > 4 is vital for effective management of gastroesophageal reflux disease (GERD). Esomeprazole 40 mg, the first proton pump inhibitor developed as an optical isomer, demonstrates improved acid inhibition over omeprazole 20 mg. Our aim was to compare esomeprazole 40 mg with omeprazole 40 mg, once-daily, on intragastric acidity in patients with symptoms of GERD. In this open-label, crossover study, 130 patients with symptoms of GERD received esomeprazole 40 mg or omeprazole 40 mg once-daily for five days. The 24-hr intragastric pH was monitored on days 1 and 5 of each treatment period. The mean percentage of the 24-hr period with intragastric pH > 4 was significantly greater (P < 0.001) with esomeprazole 40 mg than with omeprazole 40 mg on days 1 (48.6% vs 40.6%) and 5 (68.4% vs 62.0%). Interpatient variability was significantly less with esomeprazole than omeprazole. Esomeprazole was well tolerated. In conclusion, esomeprazole 40 mg provides more effective acid control than twice the standard dose of omeprazole.

Dig Dis Sci. 2002 May;47(5):954-8

Use of proton pump inhibitors and the risk of community-acquired pneumonia: a population-based case-control study.

BACKGROUND: Recently, the use of proton pump inhibitors (PPIs) has been associated with an increased risk of pneumonia. We aimed to confirm this association and to identify the risk factors. METHODS: We conducted a population-based case-control study using data from the County of Funen, Denmark. Cases (n=7642) were defined as all patients with a first-discharge diagnosis of community-acquired pneumonia from a hospital during 2000 through 2004. We also selected 34 176 control subjects, who were frequency matched to the cases by age and sex. Data on the use of PPIs and other drugs, on microbiological samples, on x-ray examination findings, and on comorbid conditions were extracted from local registries. Confounders were controlled by logistic regression. RESULTS: The adjusted odds ratio (OR) associating current use of PPIs with community-acquired pneumonia was 1.5 (95% confidence interval [CI], 1.3-1.7). No association was found with histamine(2)-receptor antagonists (OR, 1.10; 95% CI, 0.8-1.3) or with past use of PPIs (OR, 1.2; 95% CI, 0.9-1.6). Recent initiation of treatment with PPIs (0-7 days before index date) showed a particularly strong association with community-acquired pneumonia (OR, 5.0; 95% 2.1-11.7), while the risk decreased with treatment that was started a long time ago (OR, 1.3; 95% CI, 1.2-1.4). Subgroup analyses revealed high ORs for users younger than 40 years (OR, 2.3; 95% CI, 1.3-4.0). No dose-response effect could be demonstrated. CONCLUSION: The use of PPIs, especially when recently begun, is associated with an increased risk of community-acquired pneumonia.

Arch Intern Med. 2007 May 14;167(9):950-5

Systematic review: the use of proton pump inhibitors and increased susceptibility to enteric infection.

BACKGROUND: The use of proton pump inhibitors (PPIs) is increasing worldwide. Suppression of gastric acid alters the susceptibility to enteric bacterial pathogens. AIM:  This systematic review was undertaken to examine the relationship between PPI use and susceptibility to enteric infections by a specific pathogen based on published literature and to discuss the potential mechanisms of PPI enhanced pathogenesis of enteric infections. METHODS:  PubMed, OVID Medline Databases were searched. Search terms included proton pump inhibitors and mechanisms of, actions of, gastric acid, enteric infections, diarrhoea, Clostridium difficile, Salmonella, Shigella and Campylobacter. RESULTS: The use of PPIs increases gastric pH, encourages growth of the gut microflora, increases bacterial translocation and alters various immunomodulatory and anti-inflammatory effects. Enteric pathogens show variable gastric acid pH susceptibility and acid tolerance levels. By multiple mechanisms, PPIs appear to increase susceptibility to the following bacterial enteropathogens: Salmonella, Campylobacter jejuni, invasive strains of Escherichia coli, vegetative cells of Clostridium difficile, Vibrio cholerae and Listeria. We describe the available evidence for enhanced susceptibility to enteric infection caused by Salmonella, Campylobacter and C. difficile by PPI use, with adjusted relative risk ranges of 4.2-8.3 (two studies); 3.5-11.7 (four studies); and 1.2-5.0 (17 of 27 studies) for the three respective organisms. CONCLUSIONS: Severe hypochlorhydria generated by PPI use leads to bacterial colonisation and increased susceptibility to enteric bacterial infection. The clinical implication of chronic PPI use among hospitalized patients placed on antibiotics and travellers departing for areas with high incidence of diarrhoea should be considered by their physicians.

Aliment Pharmacol Ther. 2011 Dec;34
(11-12):1269-81

Rebound acid hypersecretion after long-term inhibition of gastric acid secretion.

BACKGROUND: Rebound acid hypersecretion develops after the use of acid inhibitors. AIM: To estimate the duration of hypersecretion and to elucidate the role of the enterochromaffin-like (ECL) cell in rebound acid hypersecretion. METHODS: Patients waiting for anti-reflux surgery who had used a proton pump inhibitor daily > 1 year were included. All patients discontinued taking acid inhibiting drugs after the operation. Basal and pentagastrin stimulated acid output was measured at 4, 8, 16 and 26 weeks postoperatively. Oxyntic mucosal biopsies were collected before and 26 weeks after the operation for counting of histidine decarboxylase (HDC) immunoreactive cells. Serum chromogranin A (CgA) and gastrin were measured before and at 4, 8, 16 and 26 weeks after the operation. RESULTS: Pentagastrin stimulated acid secretion was higher at 4 and 8 weeks than at 26 weeks after the operation. Gastrin and CgA were significantly reduced at 4 and 8 weeks, respectively. The number of HDC immunoreactive cells was reduced by 60% at 26 weeks postoperative. DISCUSSION: Rebound acid hypersecretion lasts more than 8 weeks, but less than 26 weeks after long-term proton pump inhibition. CONCLUSION: The findings indicate that not only the parietal cell mass, but also ECL cell mass and activity are involved in the mechanism of acid hypersecretion.

Aliment Pharmacol Ther. 2005 Jan 15;21(2):149-54

Proton pump inhibitor use, hip fracture, and change in bone mineral density in postmenopausal women: results from the Women’s Health Initiative.

BACKGROUND: Proton pump inhibitor (PPI) medications have been inconsistently shown to be associated with osteoporotic fractures. We examined the association of PPI use with bone outcomes (fracture, bone mineral density [BMD]). METHODS: This prospective analysis included 161 806 postmenopausal women 50 to 79 years old, without history of hip fracture, enrolled in the Women’s Health Initiative (WHI) Observational Study and Clinical Trials with a mean (SD) follow-up of 7.8 (1.6) years. Analyses were conducted for 130 487 women with complete information. Medication information was taken directly from drug containers during in-person interviews (baseline, year 3). The main outcome measures were self-reported fractures (hip [adjudicated], clinical spine, forearm or wrist, and total fractures) and for a subsample (3 densitometry sites), 3-year change in BMD. RESULTS: During 1,005 126 person-years of follow-up, 1500 hip fractures, 4,881 forearm or wrist fractures, 2,315 clinical spine fractures, and 21,247 total fractures occurred. The multivariate-adjusted hazard ratios for current PPI use were 1.00 (95% confidence interval [CI], 0.71-1.40) for hip fracture, 1.47 (95% CI, 1.18-1.82) for clinical spine fracture, 1.26 (95% CI, 1.05-1.51) for forearm or wrist fracture, and 1.25 (95% CI, 1.15-1.36) for total fractures. The BMD measurements did not vary between PPI users and nonusers at baseline. Use of PPIs was associated with only a marginal effect on 3-year BMD change at the hip (P = .05) but not at other sites. CONCLUSION: Use of PPIs was not associated with hip fractures but was modestly associated with clinical spine, forearm or wrist, and total fractures.

Arch Intern Med. 2010 May 10;170(9):765-71

Recurrent community-acquired pneumonia in patients starting acid-suppressing drugs.

BACKGROUND: Several studies suggest that proton pump inhibitors (PPIs) and histamine 2-receptor antagonists (H2s) increase risk of community-acquired pneumonia. To test this hypothesis, we examined a prospective population-based cohort predisposed to pneumonia: elderly patients (> or =65 years) who had survived hospitalization for pneumonia. METHODS: This study featured a nested case-control design where cases were patients hospitalized for recurrent pneumonia (> or =30 days after initial episode) and controls were age, sex, and incidence-density sampling matched but never had recurrent pneumonia. PPI/H2 exposure was classified as never, past, or current use before recurrent pneumonia. The association between PPI/H2s and pneumonia was assessed using multivariable conditional logistic regression. RESULTS: During 5.4 years of follow-up, 248 recurrent pneumonia cases were matched with 2,476 controls. Overall, 71 of 608 (12%) current PPI/H2 users had recurrent pneumonia, compared with 130 of 1,487 (8%) nonusers (adjusted odds ratio [aOR] 1.5; 95% confidence interval [CI], 1.1-2.1). Stratifying the 608 current users according to timing of PPI/H2 initiation revealed incident current-users (initiated PPI/H2 after initial pneumonia hospitalization, n=303) bore the entire increased risk of recurrent community-acquired pneumonia (15% vs 8% among nonusers, aOR 2.1; 95% CI, 1.4-3.0). The 305 prevalent current-users (PPI/H2 exposure before and after initial community-acquired pneumonia hospitalization) were equally likely to develop recurrent pneumonia as nonusers (aOR 0.99; 95% CI, 0.63-1.57). CONCLUSION: Acid-suppressing drug use substantially increased the likelihood of recurrent pneumonia in high-risk elderly patients. The association was confined to patients initiating PPI/H2s after hospital discharge. Our findings should be considered when deciding to prescribe these drugs in patients with a recent history of pneumonia.

Am J Med. 2010 Jan;123(1):47-53

Symptomatic gastroesophageal reflux as a risk factor for esophageal adenocarcinoma.

BACKGROUND: The causes of adenocarcinomas of the esophagus and gastric cardia are poorly understood. We conducted an epidemiologic investigation of the possible association between gastroesophageal reflux and these tumors. METHODS: We performed a nationwide, population-based, case-control study in Sweden. Case ascertainment was rapid, and all cases were classified uniformly. Information on the subjects’ history of gastroesophageal reflux was collected in personal interviews. The odds ratios were calculated by logistic regression, with multivariate adjustment for potentially confounding variables. RESULTS: Of the patients interviewed, the 189 with esophageal adenocarcinoma and the 262 with adenocarcinoma of the cardia constituted 85 percent of the 529 patients in Sweden who were eligible for the study during the period from 1995 through 1997. For comparison, we interviewed 820 control subjects from the general population and 167 patients with esophageal squamous-cell carcinoma. Among persons with recurrent symptoms of reflux, as compared with persons without such symptoms, the odds ratios were 7.7 (95 percent confidence interval, 5.3 to 11.4) for esophageal adenocarcinoma and 2.0 (95 percent confidence interval, 1.4 to 2.9) for adenocarcinoma of the cardia. The more frequent, more severe, and longer-lasting the symptoms of reflux, the greater the risk. Among persons with long-standing and severe symptoms of reflux, the odds ratios were 43.5 (95 percent confidence interval, 18.3 to 103.5) for esophageal adenocarcinoma and 4.4 (95 percent confidence interval, 1.7 to 11.0) for adenocarcinoma of the cardia. The risk of esophageal squamous-cell carcinoma was not associated with reflux (odds ratio, 1.1; 95 percent confidence interval, 0.7 to 1.9). CONCLUSIONS: There is a strong and probably causal relation between gastroesophageal reflux and esophageal adenocarcinoma. The relation between reflux and adenocarcinoma of the gastric cardia is relatively weak.

N Engl J Med. 1999 Mar 18;340(11):825-31

Post-prandial reflux suppression by a raft-forming alginate (Gaviscon Advance) compared to a simple antacid documented by magnetic resonance imaging and pH-impedance monitoring: mechanistic assessment in healthy volunteers and randomised, controlled, double-blind study in reflux patients.

BACKGROUND: Alginates form a raft above the gastric contents, which may suppress gastro-oesophageal reflux; however, inconsistent effects have been reported in mechanistic and clinical studies. AIMS: To visualise reflux suppression by an alginate-antacid [Gaviscon Advance (GA), Reckitt Benckiser, UK] compared with a nonraft-forming antacid using magnetic resonance imaging (MRI), and to determine the feasibility of pH-impedance monitoring for assessment of reflux suppression by alginates. METHODS: Two studies were performed: (i) GA and antacid (Alucol, Wander Ltd, Switzerland) were visualised in the stomach after ingestion in 12 healthy volunteers over 30 min after a meal by MRI, with reflux events documented by manometry. (ii) A randomised controlled, double-blind cross-over trial of post-prandial reflux suppression documented by pH-impedance in 20 patients randomised to GA or antacid (Milk of Magnesia; Boots, UK) after two meals taken 24 h apart. RESULTS: MRI visualized a “mass” of GA form at the oesophago-gastric junction (OGJ); simple antacid sank to the distal stomach. The number of post-prandial common cavity reflux events was less with GA than antacid [median 2 (0-5) vs. 5 (1-11); P < 0.035]. Distal reflux events and acid exposure measured by pH-impedance were similar after GA and antacid. There was a trend to reduced proximal reflux events with GA compared with antacid [10.5 (8.9) vs. 13.9 (8.3); P = 0.070]. CONCLUSIONS: Gaviscon Advance forms a ‘mass’ close to the OGJ and significantly suppresses reflux compared with a nonraft-forming antacid. Standard pH-impedance monitoring is suitable for clinical studies of GA in gastro-oesophageal reflux disease patients where proximal reflux is the primary outcome.

Aliment Pharmacol Ther. 2013 Jun;37(11):1093-102

Review article: alginate-raft formulations in the treatment of heartburn and acid reflux.

Alginate-based raft-forming formulations have been marketed word-wide for over 30 years under various brand names, including Gaviscon. They are used for the symptomatic treatment of heartburn and oesophagitis, and appear to act by a unique mechanism which differs from that of traditional antacids. In the presence of gastric acid, alginates precipitate, forming a gel. Alginate-based raft-forming formulations usually contain sodium or potassium bicarbonate; in the presence of gastric acid, the bicarbonate is converted to carbon dioxide which becomes entrapped within the gel precipitate, converting it into a foam which floats on the surface of the gastric contents, much like a raft on water. Both in vitro and in vivo studies have demonstrated that alginate-based rafts can entrap carbon dioxide, as well as antacid components contained in some formulations, thus providing a relatively pH-neutral barrier. Several studies have demonstrated that the alginate raft can preferentially move into the oesophagus in place, or ahead, of acidic gastric contents during episodes of gastro-oesophageal reflux; some studies further suggest that the raft can act as a physical barrier to reduce reflux episodes. Although some alginate-based formulations also contain antacid components which can provide significant acid neutralization capacity, the efficacy of these formulations to reduce heartburn symptoms does not appear to be totally dependent on the neutralization of bulk gastric contents. The strength of the alginate raft is dependant on several factors, including the amount of carbon dioxide generated and entrapped in the raft, the molecular properties of the alginate, and the presence of aluminium or calcium in the antacid components of the formulation. Raft formation occurs rapidly, often within a few seconds of dosing; hence alginate-containing antacids are comparable to traditional antacids for speed of onset of relief. Since the raft can be retained in the stomach for several hours, alginate-based raft-forming formulations can additionally provide longer-lasting relief than that of traditional antacids. Indeed, clinical studies have shown Gaviscon is superior to placebo, and equal to or significantly better than traditional antacids for relieving heartburn symptoms. Alginate-based, raft-forming formulations have been used to treat reflux symptoms in infants and children, and in the management of heartburn and reflux during pregnancy. While Gaviscon is effective when used alone, it is compatible with, and does not interfere with the activity of antisecretory agents such as cimetidine. Even with the introduction of new antisecretory and promotility agents, alginate-rafting formulations will continue to have a role in the treatment of heartburn and reflux symptoms. Their unique non-systemic mechanism of action provides rapid and long-duration relief of heartburn and acid reflux symptoms.

Aliment Pharmacol Ther. 2000 Jun;14(6):669-90

Gastroesophageal reflux disease and tooth erosion.

The increasing prevalence of gastroesophageal reflux disease (GERD) in children and adults, and of “silent refluxers” in particular, increases the responsibility of dentists to be alert to this potentially severe condition when observing unexplained instances of tooth erosion. Although gastroesophageal reflux is a normal physiologic occurrence, excessive gastric and duodenal regurgitation combined with a decrease in normal protective mechanisms, including an adequate production of saliva, may result in many esophageal and extraesophageal adverse conditions. Sleep-related GERD is particularly insidious as the supine position enhances the proximal migration of gastric contents, and normal saliva production is much reduced. Gastric acid will displace saliva easily from tooth surfaces, and proteolytic pepsin will remove protective dental pellicle. Though increasing evidence of associations between GERD and tooth erosion has been shown in both animal and human studies, relatively few clinical studies have been carried out under controlled trial conditions. Suspicion of an endogenous source of acid being associated with observed tooth erosion requires medical referral and management of the patient as the primary method for its prevention and control.

Int J Dent. 2012;2012:479850

Patterns of food and acid reflux in patients with low-grade oesophagitis—the role of an anti-reflux agent.

BACKGROUND: Food and acid have been shown to be refluxed independently of each other in healthy volunteers, and anti-reflux agents decrease the reflux of both parameters. Until now this phenomenon had not been studied in patients with low-grade oesophagitis, who are the group most likely to use anti-reflux medication. AIM: To assess patterns of gastro-oesophageal reflux of acid and food in 12 ambulant patients with endoscopically proven oesophagitis of between grades I and II, but who were otherwise healthy. Also to assess the effectiveness of a single dose of an alginate-containing anti-reflux agent in controlling food and acid reflux in this patient group. METHODS: Oesophageal pH monitoring and external ambulatory gamma detection were used to study food and acid reflux. A pH electrode was positioned 5 cm above the cardia and the gamma detector was positioned externally over the pH electrode. The patients then received a technetium-99m labelled meal designed to provoke reflux. Thirty minutes later the patients were given a 20 ml dose of alginate (Liquid Gaviscon), or 20 ml of tap water. Incidence of reflux was monitored for approximately 4 h from the end of the meal. Allocation to treatment group was randomized, with patients receiving the alternative treatment on the second study day after approximately a 7-day washout period. RESULTS: The mean percentage time oesophageal pH remained below 4 was 16.3 min for the control group and 5.4 min for the treatment group (P = 0.03). Food reflux was detected 23.7% of the time in the control group compared to 12% of the time in the treatment group (P = 0.02). The anti-reflux agent was also successful in decreasing the number of events, but the duration of the reflux events was not significantly different. CONCLUSIONS: Patients with grades I and II oesophagitis reflux food and acid independently, and are predominantly either food refluxers or acid refluxers, but not both. Liquid alginate decreases the number of both food and acid reflux events, but does not change their duration.

Aliment Pharmacol Ther. 1998 Jan;12(1):53-8

A comparison of the efficacy of the alginate preparation, Gaviscon Advance, with placebo in the treatment of gastro-oesophageal reflux disease.

The aim of this study was to compare the efficacy of the sodium alginate preparation, Gaviscon Advance, with placebo in the relief of symptoms of reflux oesophagitis. This was a randomised, double-blind, parallel-group, multicentre study conducted at 13 GP centres in the UK. Patients aged between 18 and 70 years, who had experienced symptoms of reflux oesophagitis within the previous 24 h, and on two other occasions within the previous week, were recruited into the study. Patients were evaluated at baseline, and then reassessed after two and four weeks of treatment with sodium alginate or placebo, for symptoms of reflux oesophagitis in the previous 24 h. Patients were required to fill out a diary card twice daily, from which frequency and severity of symptoms were assessed, and the percentage of symptom-free days and nights calculated. Of the 100 patients recruited into the study, 98 received medication (safety population; placebo, n = 50; sodium alginate, n = 48) and 94 were eligible for inclusion in the intention-to-treat (ITT) population (placebo, n = 48; sodium alginate, n = 46). For this population, sodium alginate was assessed as significantly superior by both investigators and patients at week two (p < 0.001 and p = 0.004, respectively) and at week four (p = 0.001 and p < 0.001, respectively). Significantly more patients in the safety population on placebo withdrew from the study (40%) compared with sodium alginate (21%; p = 0.04), due primarily to lack of effect and adverse events. The sodium alginate preparation demonstrated a superior efficacy compared with placebo, which was achieved in a more acceptable volume of medication than a previous standard preparation, Liquid Gaviscon. The reduced dosage volume of the ‘new’ preparation (Gaviscon Advance) may be expected to improve patient compliance, and thereby increase treatment efficacy.

Curr Med Res Opin. 1999;15(3):152-9

Glycation

Ultraviolet radiation and skin aging: roles of reactive oxygen species, inflammation and protease activation, and strategies for prevention of inflammation-induced matrix degradation - a review.

Inflammation and the resulting accumulation of reactive oxygen species (ROS) play an important role in the intrinsic and photoaging of human skin in vivo. Environmental insults such as ultraviolet (UV) rays from sun, cigarette smoke exposure and pollutants, and the natural process of aging contribute to the generation of free radicals and ROS that stimulate the inflammatory process in the skin. UV irradiation initiates and activates a complex cascade of biochemical reactions in human skin. In short, UV causes depletion of cellular antioxidants and antioxidant enzymes (SOD, catalase), initiates DNA damage leading to the formation of thymidine dimmers, activates the neuroendocrine system leading to immunosuppression and release of neuroendocrine mediators, and causes increased synthesis and release of pro-inflammatory mediators from a variety of skin cells. The pro-inflammatory mediators increase the permeability of capillaries leading to infiltration and activation of neutrophils and other phagocytic cells into the skin. The net result of all these effects is inflammation and free radical generation (both reactive oxygen and nitrogen species). Furthermore, elastsases and other proteases (cathepsin G) released from neutrophils cause further inflammation, and activation of matrix metalloproteases. The inflammation further activates the transcription of various matrixes degrading metalloproteases, leading to abnormal matrix degradation and accumulation of non-functional matrix components. In addition, the inflammation and ROS cause oxidative damage to cellular proteins, lipids and carbohydrates, which accumulates in the dermal and epidermal compartments, contributing to the aetiology of photoaging. Strategies to prevent photodamage caused by this cascade of reactions initiated by UV include: prevention of UV penetration into skin by physical and chemical sunscreens, prevention/reduction of inflammation using anti-inflammatory compounds (e.g. cyclooxygenase inhibitors, inhibitors of cytokine generation); scavenging and quenching of ROS by antioxidants; inhibition of neutrophil elastase activity to prevent extracellular matrix damage and activation of matrix metalloproteases (MMPs), and inhibition of MMP expression (e.g. by retinoids) and activity (e.g. by natural and synthetic inhibitors).

Int J Cosmet Sci. 2005 Feb;27(1):17-34

UV-induced DNA damage initiates release of MMP-1 in human skin.

Destruction of collagen is a hallmark of photoaging. The major enzyme responsible for collagen 1 digestion, matrix metalloproteinase-1 (MMP-1), is induced by exposure to sunlight. To study the molecular trigger for this induction, human skin was ultraviolet-B (UVB)-irradiated and treated with liposome-encapsulated DNA repair enzymes. The photolyase-mediated DNA repair of epidermal UV damage was associated with a reduction of MMP-1 mRNA and protein expression in both the epidermal and dermal compartments of the skin. The role of the epidermal cells in MMP-1 induction in the fibroblasts was examined when human epidermal keratinocytes were irradiated with UVB and their media were transferred to unirradiated human dermal fibroblasts. Transfer of media from irradiated keratinocytes to unirradiated fibroblasts enhanced MMP-1 mRNA and protein. Thus, UV damage to keratinocytes of the epidermis may participate in the destruction of collagen in the dermis by release of soluble mediators that signal fibroblasts to release MMP-1. The MMP-1 induction was reduced when the keratinocytes were treated with DNA repair enzymes T4 endonuclease V or UV endonuclease prior to transfer of the media to fibroblasts. This implies that UVB, which deposits most of its energy on the chromatin of the epidermal keratinocytes and to a lesser extent in the upper dermis, has a significant role in photoaging. DNA damage in the keratinocytes initiates one of the signals for MMP-1 release, and enhancing DNA repair can reduce MMP-1 expression in human skin cells and tissue.

Exp Dermatol. 2008 Dec;17(12):1037-44

Expression of advanced glycation end-products on sun-exposed and non-exposed cutaneous sites during the ageing process in humans.

The glycation process is involved in both the intrinsic (individual, genetic) and extrinsic (ultraviolet light, polution and lifestyle) aging processes, and can be quantified at the epidermal or dermal level by histological, immunohistochemical (IHC), or imagistic methods. Our study is focused on a histological and immunohistological comparison of sun-protected regions versus sun-exposed regions from different age groups of skin phototype III subjects, related to the aging process. Skin samples collected from non-protected and UV protected regions of four experimental groups with different ages, were studied using histology and IHC methods for AGE-CML [N(epsilon)-(carboxymethyl)lysine]. A semi-quantitative assessment of the CML expression in the microvascular endothelium and dermal fibroblasts was performed. The Pearson one-way ANOVA was used to compare data between the groups. In the dermis of sun-exposed skin, the number and the intensity of CML positive cells in both fibroblasts and endothelial cells (p<0.05) was higher compared to sun-protected skin, and was significantly increased in older patients. The sun-exposed areas had a more than 10% higher AGE-CML score than the protected areas. No statistically significant correlation was observed between the histological score and the IHC expression of CML. We concluded that in healthy integument, the accumulation of final glycation products increases with age and is amplified by ultraviolet exposure. The study provides new knowledge on differences of AGE-CML between age groups and protected and unprotected areas and emphasizes that endothelium and perivascular area are most affected, justifying combined topical and systemic therapies.

PLoS One. 2013 Oct 7;8(10):e75003

The development of Terminalia chebula Retz. (Combretaceae) in clinical research.

Medicinal plants are part and parcel of human society to combat diseases from the dawn of civilization. Terminalia chebula Retz. (Fam. Combretaceae), is called the ‘King of Medicine’ in Tibet and is always listed at the top of the list of ‘Ayurvedic Materia Medica’ because of its extraordinary power of healing. The whole plant possesses high medicinal value and traditionally used for the treatment of various ailments for human beings. Some of the folklore people used this plant in the treatment of asthma, sore throat, vomiting, hiccough, diarrhea, dysentery, bleeding piles, ulcers, gout, heart and bladder diseases. The plant has been demonstrated to possess multiple pharmacological and medicinal activities, such as antioxidant, antimicrobial, antidiabetic, hepatoprotective, anti-inflammatory, antimutagenic, antiproliferative, radioprotective, cardioprotective, antiarthritic, anticaries, gastrointestinal motility and wound healing activity. But no systematic updated information on the therapeutic effectiveness of Terminalia chebula, a popular herbal remedy in India and South-East Asia has so far been reported. This review highlights an updated information particularly on the phytochemistry and various pharmacological and medicinal properties of Terminalia chebula Retz. and some of its isolated compounds, along with their safety evaluation. This may provide incentive for proper evaluation of the plant as medicinal agent against the human diseases and also to bridge the lacunae in the existing literature and future scope which may offer immense opportunity for researchers engaged in validation of the traditional claims and development of safe and effective botanical medicine.

Asian Pac J Trop Biomed. 2013 Mar;3(3):244-52

Preventive effects of chebulic acid isolated from Terminalia chebula on advanced glycation endproduct-induced endothelial cell dysfunction.

AIM OF THE STUDY: The aqueous extract of Terminalia chebular fruits was reported to have anti-hyperglycemia and anti-diabetic complication effects. The present study therefore investigated the protective mechanism of chebulic acid, a phenolcarboxylic acid compound isolated from the ripe fruits of Terminalia chebula against advanced glycation endproducts (AGEs)-induced endothelial cell dysfunction. MATERIALS AND METHODS: To investigate the protective mechanism of chebulic acid against vascular endothelial dysfunction human umbilical vein endothelial cells (HUVEC) were treated with chebulic acid in the presence/absence of glyceraldehyde-related AGEs (glycer-AGEs). RESULTS: HUVEC incubated with 100 µg/ml of glycer-AGEs had significantly enhanced reactive oxygen species formation, whereas the treatment of chebulic acid dose-dependently reduced glycer-AGE-induced formation to 108.2 ± 1.9% for 25 µM versus 137.8 ± 1.1% for glycer-AGEs treated alone. The transendothelial electrical resistance (TER) value of the glycer-AGEs group was dramatically decreased to 76.9 ± 2.2% compared to the control, whereas chebulic acid treatment prevented glycer-AGE-induced TER change with a value of 91.3 ± 5.3%. The incubation of confluent HUVEC with 100 µg/ml of glycer-AGEs for 24h remarkably increased the adhesion of human monocytic THP-1 cells compared to non-stimulated HUVEC. These increases in HUVEC adhesiveness were dose-dependently reduced by chebulic acid. CONCLUSIONS: The present study shows the effects of chebulic acid against the progression of AGE-induced endothelial cell dysfunction suggesting that this compound may constitute a promising intervention agent against diabetic vascular complications.

J Ethnopharmacol. 2010 Oct 5;131(3):567-74

Inhibitory effects of Terminalia chebula extract on glycation and endothelial cell adhesion.

Terminalia chebula Retz. has been used in India for a long time to treat many diseases, and its extract was reported to have antidiabetic activity in vivo. In this study, T. chebula methanolic extract (TCE) containing 2.7 % chebulic acid was evaluated for its preventive effects against the formation of advanced glycation end products (AGEs) and endothelial cell dysfunction. When the effects of TCE on AGE formation and on protein crossing-linking by glycation with D-threose and lens crystallines were examined, TCE showed inhibitory activity in a dose-dependent manner, and the concentration of 1,000 µg/mL presented an activity similar to that of 5 mM aminoguanidine as a positive control. Upon investigating the protective activity of TCE against AGE-induced vascular endothelium dysfunction, human umbilical vein endothelial cells (HUVEC) incubated with 100 µg/mL of AGEs had significantly enhanced reactive oxygen species (ROS) formation, whereas the treatment of T. chebula reduced AGE-induced ROS generation. The incubation of HUVEC with 100 µg/mL of AGEs caused a considerable increase in THP-1 monocytic cell adhesion, but this adhesion was reduced by the treatment of TCE. These results suggest that TCE is a potential agent for alleviating diabetic complications.

Planta Med. 2011 Jul;77(10):1060-7

Absorption of anthocyanins from blueberries and serum antioxidant status in human subjects.

In recent years, numerous studies have shown that the polyphenolics present in fruit and vegetable products exhibit a wide range of biological effects. However, there is little reliable information on the absorption of glycosylated and acylated anthocyanins in humans. In the present study, the absorption of anthocyanins in humans was investigated after the consumption of a high-fat meal with a freeze-dried blueberry powder containing 25 individual anthocyanins including 6 acylated structures. Nineteen of the 25 anthocyanins present in the blueberries were detected in human blood serum. Furthermore, the appearance of total anthocyanins in the serum was directly correlated with an increase in serum antioxidant capacity (ORAC(acetone), P < 0.01). These results show that anthocyanins can be absorbed in their intact glycosylated and possibly acylated forms in human subjects and that consumption of blueberries, a food source with high in vitro antioxidant properties, is associated with a diet-induced increase in ex vivo serum antioxidant status.

J Agric Food Chem. 2002 Dec 18;50(26):7731-7

Survey of antioxidant capacity and phenolic composition of blueberry, blackberry, and strawberry in Nanjing.

Berries are a good source of natural antioxidants. In the present study, the total antioxidant capacity and phenolic composition of three berry fruits (blueberry, blackberry, and strawberry) cultivated in Nanjing were investigated. Blueberry, with a Trolox equivalent antioxidant capacity (TEAC) value of 14.98 mmol Trolox/100 g dry weight (DW), exhibited the strongest total antioxidant capacity using both the 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. Blueberry also had the highest total phenolic content (TPC, 9.44 mg gallic acid/g DW), total flavonoid content (TFC, 36.08 mg rutin/g DW), and total anthocyanidin content (TAC, 24.38 mg catechin/g DW). A preliminary analysis using high performance liquid chromatography (HPLC) showed that the blueberry, blackberry, and strawberry samples tested contained a range of phenolic acids (including gallic acid, protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid, p-coumaric acid, ferulic acid, ellagic acid, and cinnamic acid) and various types of flavonoids (flavone: luteolin; flavonols: rutin, myricetin, quercetrin, and quercetin; flavanols: gallocatechin, epigallocatechin, catechin, and catechin gallate; anthocyanidins: malvidin-3-galactoside, malvidin-3-glucoside, and cyanidin). In particular, the blueberries had high levels of proanthocyanidins and anthocyanidins, which might be responsible for their strong antioxidant activities. These results indicate a potential market role for berries (especially blueberries) as a functional food ingredient or nutraceutical.

J Zhejiang Univ Sci B. 2012 Feb;13(2):94-102

Anti-inflammatory effect of the blueberry anthocyanins malvidin-3-glucoside and malvidin-3-galactoside in endothelial cells.

Blueberry fruits have a wide range of health benefits because of their abundant anthocyanins, which are natural antioxidants. The purpose of this study was to investigate the inhibitory effect of blueberry’s two main anthocyanins (malvidin-3-glucoside and malvidin-3-galactoside) on inflammatory response in endothelial cells. These two malvidin glycosides could inhibit tumor necrosis factor-alpha (TNF-a) induced increases of monocyte chemotactic protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) production both in the protein and mRNA levels in a concentration-dependent manner. Mv-3-glc at the concentration of 1 µM could inhibit 35.9% increased MCP-1, 54.4% ICAM-1, and 44.7% VCAM-1 protein in supernatant, as well as 9.88% MCP-1 and 48.6% ICAM-1 mRNA expression (p<0.05). In addition, they could decrease IkBa degradation (Mv-3-glc, Mv-3-gal, and their mixture at the concentration of 50 µM had the inhibition rate of 84.8%, 75.3%, and 43.2%, respectively, p<0.01) and block the nuclear translocation of p65, which suggested their anti-inflammation mechanism was mediated by the nuclear factor-kappa B (NF-kB) pathway. In general malvidin-3-glucoside had better anti-inflammatory effect than malvidin-3-galactoside. These results indicated that blueberry is good resource of anti-inflammatory anthocyanins, which can be promising molecules for the development of nutraceuticals to prevent chronic inflammation in many diseases.

Molecules. 2014 Aug 21;19(8):12827-41

Receptor for advanced glycation end products (RAGE): a novel therapeutic target for diabetic vascular complication.

Diabetic vascular complication is a leading cause of acquired blindness, end-stage renal failure, a variety of neuropathies and accelerated atherosclerosis, which could account for disabilities and high mortality rates in patients with diabetes. Although several hyperglycemia-elicited metabolic and hemodynamic derangements have been implicated in the pathogenesis of diabetic vascular complication, the process of formation and accumulation of advanced glycation end products (AGEs) and their mode of action are most compatible with the theory ‘hyperglycemic memory’. Further, there is a growing body of evidence that AGEs and their receptor (RAGE) axis is involved in the pathogenesis of diabetic vascular complication. Indeed, the engagement of RAGE with AGEs is shown to elicit oxidative stress generation and subsequently evoke inflammatory responses in various types of cells, thus playing an important role in the development and progression of diabetic micro- and macroangiopathy. These observations suggest that down-regulation of RAGE expression or blockade of the RAGE downstream signaling may be a promising target for therapeutic intervention in diabetic vascular complication. In this review, we discuss several types of agents that could potentially inhibit RAGE expression or its downstream pathways and their therapeutic implications in diabetic vascular complication.

Curr Pharm Des. 2008;14(5):487-95

Advanced glycation end products and RAGE: a common thread in aging, diabetes, neurodegeneration, and inflammation.

The products of nonenzymatic glycation and oxidation of proteins and lipids, the advanced glycation end products (AGEs), accumulate in a wide variety of environments. AGEs may be generated rapidly or over long times stimulated by a range of distinct triggering mechanisms, thereby accounting for their roles in multiple settings and disease states. A critical property of AGEs is their ability to activate receptor for advanced glycation end products (RAGE), a signal transduction receptor of the immunoglobulin superfamily. It is our hypothesis that due to such interaction, AGEs impart a potent impact in tissues, stimulating processes linked to inflammation and its consequences. We hypothesize that AGEs cause perturbation in a diverse group of diseases, such as diabetes, inflammation, neurodegeneration, and aging. Thus, we propose that targeting this pathway may represent a logical step in the prevention/treatment of the sequelae of these disorders.

Glycobiology. 2005 Jul;15(7):16R-28R

Reconstructed skin modified by glycation of the dermal equivalent as a model for skin aging and its potential use to evaluate anti-glycation molecules.

Glycation is a slow chemical reaction which takes place between amino residues in protein and a reducing sugar. In skin this reaction creates new residues or induces the formation of cross-links (advanced glycation end products or AGEs) in the extracellular matrix of the dermis. Formation of such cross-links between macromolecules may be responsible for loss of elasticity or modification of other properties of the dermis observed during aging. We had previously developed a reconstructed skin model which enabled us to study the consequences of matrix alteration by preglycation of the collagen and have reported several modifications of interest induced by glycation in the dermal and epidermal compartments of reconstructed skin as well as at the level of the dermal-epidermal junction. For example we showed that collagen IV and laminin were increased in the basement membrane zone and that alpha6 and beta1 integrins in epidermis were expanded to suprabasal layers. The aim of this new study was to look at the biological effects of glycation inhibitors like aminoguanidine in the skin model. Aminoguanidine was mixed with collagen in the presence of ribose as reducing sugar, and immunostaining was used to visualize its effects on AGE Products and biological markers. After aminoguanidine treatment, we found a low amount of AGE products and a possible return to the normal pattern of distribution of markers in skin constructs as compared to those treated with ribose only. Interestingly similar results were also obtained, although to a lesser extent, with a blueberry extract. In conclusion the glycation inhibitory effect has been functionally demonstrated in the reconstructed skin model and it is shown that this model can be used to assess anti-glycation agents.

Exp Gerontol. 2008 Jun;43(6):584-8

Mediterranean Trim

Depot-specific differences in perilipin and hormone-sensitive lipase expression in lean and obese.

BACKGROUND: Mainly dependent on hormone-sensitive lipase, lipolysis is differently impaired between fat depots in human obesity. Perilipin A expression is a critical element in adipocyte lipolysis. The present study aimed at comparing expression and subcellular distribution of perilipin and hormone-sensitive lipase in two abdominal adipose tissues of lean and obese women. We examined whether regional differences in perilipin expression contribute to impaired lipolytic rates. METHODS: Abdominal subcutaneous and omental adipose tissues were obtained from six lean and ten obese women. We measured total protein content and relative distribution of hormone-sensitive lipase and perilipin proteins between lipid and non-lipid fractions in tissue homogenates. Hormone-sensitive lipase and perilipin mRNA levels, adipocyte size, basal (non-stimulated) and noradrenaline-stimulated lipolysis in isolated adipocytes were determined. RESULTS: Adipocytes were significantly larger in the obese versus the lean women and in subcutaneous versus omental fat. Expressed as a function of cell number, basal lipolysis and noradrenaline responsiveness were higher in subcutaneous versus omental adipocytes from the obese women (P < 0.05). Despite higher or identical mRNA levels in the lean and the obese subjects and in subcutaneous and omental tissues, perilipin protein expression was lower in both depots in the obese versus the lean women, and in subcutaneous versus omental in both lean and obese women (P < 0.05). Perilipin was mostly (above 80%) present in the lipid fraction in both depots from the obese patients and the value decreased to 60% in the lean subjects (P < 0.05). Perilipin protein expression was inversely correlated to adipocyte size and basal lipolysis in both depots. Despite higher mRNA levels, hormone-sensitive lipase protein expression decreased in both depots of the obese women. Regional difference for hormone-sensitive lipase was reported in lipid fraction of subcutaneous fat of the obese subjects: hormone-sensitive lipase content was twice as low as in omental adipose tissue. CONCLUSION: In both fat depots, a reduced perilipin protein expression was observed in women obesity. Perilipin protein level may contribute to differences in basal lipolysis and in adipocyte size between fat depots and may regulate lipid accumulation in adipocytes. Differences in hormone-sensitive lipase subcellular distribution were reported between fat depots in the obese women.

Lipids Health Dis. 2009 Dec 18;8:58

Perilipin expression in human adipose tissue is elevated with obesity.

The perilipins are highly phosphorylated adipocyte proteins that are localized at the surface of the lipid droplet. With activation by protein kinase A, perilipins translocate away from the lipid droplet and allow hormone-sensitive lipase to hydrolyze the adipocyte triglycerides to release nonesterified fatty acids (NEFA). Because of the potential importance of adipocyte lipolysis to obesity and insulin resistance, we measured perilipin protein and mRNA levels in nondiabetic subjects with varying degrees of insulin resistance. By Northern and Western blotting, we could detect perilipin A, but not perilipin B. Perilipin A protein and mRNA levels were quantitated and were highly correlated with each other. There was a significant positive relationship between perilipin expression and obesity (r = 0.55; P < 0.01, perilipin mRNA vs. percent body fat). However, there was no significant relationship between perilipin expression and blood NEFA, nor was there a significant relationship between perilipin expression and insulin resistance, using the insulin sensitivity index derived from the iv glucose tolerance test with minimal modeling. In addition, there was no significant relationship between perilipin and adipocyte or systemic inflammatory markers, such as TNFalpha, IL-6, and adiponectin. Thus, perilipin was elevated in obese subjects, perhaps as a compensatory mechanism to limit basal lipolysis. However, there was no relationship between perilipin and insulin resistance.

J Clin Endocrinol Metab. 2004 Mar;89(3):1352-8.

Decreased expression and function of adipocyte hormone-sensitive lipase in subcutaneous fat cells of obese subjects.

Decreased lipolytic effect of catecholamines in adipose tissue has repeatedly been demonstrated in obesity and may be a cause of excess accumulation of body fat. However, the mechanisms behind this lipolysis defect are unclear. The role of hormone-sensitive lipase was examined using abdominal subcutaneous adipocytes from 34 obese drug-free and otherwise healthy males or females and 14 non-obese control subjects. The enzyme catalyzes the rate-limiting step of the lipolysis pathway. The maximum lipolytic capacity of fat cells was significantly decreased in obesity when measured using either a non-selective beta-adrenergic receptor agonist (isoprenaline) or a phosphodiesterase resistant cyclic AMP analogue (dibutyryl cyclic AMP). Likewise, enzyme activity, protein expression, and mRNA of hormone-sensitive lipase were significantly decreased in adipocytes of obese subjects. The findings were not influenced by age or gender. The data suggest that a decreased expression of hormone-sensitive lipase in subcutaneous fat cells, which in turn causes decreased enzyme function and impaired lipolytic capacity of adipocytes, is present in obesity. Impaired expression of the hormone-sensitive lipase gene might at least in part explain the enzyme defect.

J Lipid Res. 1999 Nov;40(11):2059-66

Lipolytic effect of a polyphenolic citrus dry extract of red orange, grapefruit, orange (SINETROL) in human body fat adipocytes. Mechanism of action by inhibition of cAMP-phosphodiesterase (PDE).

The present study investigated the lipolytic (break of fat stored) effect of a citrus-based polyphenolic dietary supplement (SINETROL) at human adipocytes (ex vivo), body fat (clinical) and biochemical levels (inhibition of phosphodiesterase). Free fatty acids (FFA) release was used as indicator of human adipocyte lipolysis and SINETROL activity has been compared with known lipolytic products (isoproterenol, theopylline and caffeine). SINETROL stimulated significantly the lipolytic activity in a range of 6 fold greater than the control. Moreover, SINETROL has 2.1 greater activity than guarana 12% caffeine while its content in caffeine is 3 times lower. Clinically, two groups of 10 volunteers with BMI relevant of overweight were compared during 4 and 12 weeks with 1.4 g/day SINETROL and placebo supplementation. In the SINETROL Group the body fat (%) decreased with a significant difference of 5.53% and 15.6% after 4 and 12 weeks, respectively, while the body weight (kg) decreased with a significant difference of 2.2 and 5.2 kg after 4 and 12 weeks, respectively. These observed effects are linked to SINETROL polyphenolic composition and its resulting synergistic activity. SINETROL is a potent inhibitor of cAMP-phosphodiesterase (PDE) (97%) compared to other purified compounds (cyanidin-3 glycoside, narangin, caffeine). These results suggest that SINETROL has a strong lipolytic effect mediated by cAMP-PDE inhibition. SINETROL may serve to prevent obesity by decreasing BMI.

Phytomedicine. 2008 Oct;15(10):783-92

Clinical study to assess the efficacy and safety of a citrus polyphenolic extract of red orange, grapefruit, and orange (Sinetrol-XPur) on weight management and metabolic parameters in healthy overweight individuals.

The present study investigated the efficacy and safety effects of Sinetrol-XPur (polyphenolic citrus dry extract) in weight management; metabolic parameters; and inflammatory, glycemic and oxidative status. In a 12-week, randomized, double-blind, placebo-controlled trial, Sinetrol-XPur was given to overweight subjects twice daily with meals in the tested group (N = 47) versus a placebo group (N = 48). Waist and hip circumference and abdominal fat were decreased in the Sinetrol-XPur group as compared with the placebo group (p < 0.0001) (-5.71% vs. -1.56% for waist, -4.71% vs. -1.35% for hip and -9.73% vs. -3.18% for fat). Inflammatory markers were reduced (C-reactive protein: -22.87% vs. +61%; fibrinogen: -19.93% vs. -1.61%, p < 0.01). Oxidative stress was lowered as seen by the reduction of malondialdehyde (-14.03% vs. 2.76%) and the increase in superoxide dismutase and glutathione (17.38% vs. 2.19% and 4.63% vs. -2.36%, respectively, p < 0.01). No adverse effects were observed. Kidney, liver, and lipid panels remained unchanged. These results indicated that Sinetrol-XPur supplementation is a viable option for reducing abdominal fat, waist and hip circumference, and body weight and for improving inflammatory, glycemic, and oxidative status in healthy overweight individuals.

Phytother Res. 2014 Feb;28(2):212-8

Lipid signaling in adipose tissue: Connecting inflammation & metabolism.

Obesity-associated low-grade inflammation of white adipose tissue (WAT) contributes to development of insulin resistance and other disorders. Accumulation of immune cells, especially macrophages, and macrophage polarization from M2 to M1 state, affect intrinsic WAT signaling, namely anti-inflammatory and proinflammatory cytokines, fatty acids (FA), and lipid mediators derived from both n-6 and n-3 long-chain PUFA such as (i) arachidonic acid (AA)-derived eicosanoids and endocannabinoids, and (ii) specialized pro-resolving lipid mediators including resolvins derived from both eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), lipoxins (AA metabolites), protectins and maresins (DHA metabolites). In this respect, potential differences in modulating adipocyte metabolism by various lipid mediators formed by inflammatory M1 macrophages typical of obese state, and non-inflammatory M2 macrophages typical of lean state remain to be established. Studies in mice suggest that (i) transient accumulation of M2 macrophages could be essential for the control of tissue FA levels during activation of lipolysis, (ii) currently unidentified M2 macrophage-borne signaling molecule(s) could inhibit lipolysis and re-esterification of lipolyzed FA back to triacylglycerols (TAG/FA cycle), and (iii) the egress of M2 macrophages from rebuilt WAT and removal of the negative feedback regulation could allow for a full unmasking of metabolic activities of adipocytes. Thus, M2 macrophages could support remodeling of WAT to a tissue containing metabolically flexible adipocytes endowed with a high capacity of both TAG/FA cycling and oxidative phosphorylation. This situation could be exemplified by a combined intervention using mild calorie restriction and dietary supplementation with EPA/DHA, which enhances the formation of “healthy” adipocytes. This article is part of a Special Issue entitled Oxygenated metabolism of PUFA: analysis and biological relevance.”

Biochim Biophys Acta. 2015 Apr;1851(4):503-518

Estradiol regulates insulin signaling and inflammation in adipose tissue.

Obesity-associated low-grade inflammation at white adipose tissue (WAT) leads to metabolic defects. Sex steroid hormone estrogen may be protective against high-fat diet (HFD)-induced obesity and insulin resistance. This has been tested by many previous studies utilizing rodent models of ovariectomy (OVX) and/or treatment of estradiol (E2), the major biologically active form of estrogen. Body weight and adiposity are increased by OVX and reduced following E2 treatment, however. Thus, the protective roles of E2 may be secondary effects to the changes in body weight and adiposity. We hypothesize that E2 directly prevents inflammation and maintains insulin sensitivity in WAT independent of energy status using mice with similar body weights and adiposity. MATERIALS AND METHODS: Four groups of female C57BL/6 mice were used, including sham-operated mice treated with vehicle for E2 and fed with either a low-fat diet (LFD; Sham-Veh-LFD) or a HFD (Sham-Veh-HFD), and HFD-fed OVX mice treated with either vehicle (OVX-Veh-HFD) or E2 (OVX-E2-HFD). Body weight and abdominal parametrial WAT mass, insulin signaling, and expression levels of genes related to low-grade inflammation in WAT were compared between these groups pair-fed with equal amounts of calories for a period of 4 days. RESULTS: Body weights and WAT mass were similar in all four groups. OVX-Veh-HFD mice had impaired insulin signaling associated with rapid activation of inflammation, whereas OVX-E2-HFD group maintained insulin sensitivity without showing inflammation in WAT. CONCLUSIONS: E2 directly contributed to the maintenance of insulin sensitivity during the early phase of development of metabolic dysfunction, possibly via preventing low-grade inflammation in WAT.

Horm Mol Biol Clin Investig. 2014 Feb;17(2):99-107

Low grade inflammation as a common pathogenetic denominator in age-related diseases: novel drug targets for anti-ageing strategies and successful ageing achievement.

Nowadays, people are living much longer than they used to do, however they are not free from ageing. Ageing, an inexorable intrinsic process that affects all cells, tissues, organs and individuals, is a post-maturational process that, due to a diminished homeostasis and increased organism frailty, causes a reduction of the response to environmental stimuli and, in general, is associated to an increased predisposition to illness and death. However, the high incidence of death due to infectious, cardiovascular and cancer diseases underlies a common feature in these pathologies that is represented by dysregulation of both instructive and innate immunity. Several studies show that a low-grade systemic inflammation characterizes ageing and that inflammatory markers are significant predictors of mortality in old humans. This pro-inflammatory status of the elderly underlies biological mechanisms responsible for physical function decline and age-related diseases such as Alzheimer’s disease and atherosclerosis are initiated or worsened by systemic inflammation. Understanding of the ageing process should have a prominent role in new strategies for extending the health old population. Accordingly, as extensively discussed in the review and in the accompanying related papers, investigating ageing pathophysiology, particularly disentangling age-related low grade inflammation, is likely to provide important clues about how to develop drugs that can slow or delay ageing.

Curr Pharm Des. 2010;16(6):584-96

Fat tissue, aging, and cellular senescence.

Fat tissue, frequently the largest organ in humans, is at the nexus of mechanisms involved in longevity and age-related metabolic dysfunction. Fat distribution and function change dramatically throughout life. Obesity is associated with accelerated onset of diseases common in old age, while fat ablation and certain mutations affecting fat increase life span. Fat cells turn over throughout the life span. Fat cell progenitors, preadipocytes, are abundant, closely related to macrophages, and dysdifferentiate in old age, switching into a pro-inflammatory, tissue-remodeling, senescent-like state. Other mesenchymal progenitors also can acquire a pro-inflammatory, adipocyte-like phenotype with aging. We propose a hypothetical model in which cellular stress and preadipocyte overutilization with aging induce cellular senescence, leading to impaired adipogenesis, failure to sequester lipotoxic fatty acids, inflammatory cytokine and chemokine generation, and innate and adaptive immune response activation. These pro-inflammatory processes may amplify each other and have systemic consequences. This model is consistent with recent concepts about cellular senescence as a stress-responsive, adaptive phenotype that develops through multiple stages, including major metabolic and secretory readjustments, which can spread from cell to cell and can occur at any point during life. Senescence could be an alternative cell fate that develops in response to injury or metabolic dysfunction and might occur in nondividing as well as dividing cells. Consistent with this, a senescent-like state can develop in preadipocytes and fat cells from young obese individuals. Senescent, pro-inflammatory cells in fat could have profound clinical consequences because of the large size of the fat organ and its central metabolic role.

Aging Cell. 2010 Oct;9(5):667-84

Adipocyte lipases and defect of lipolysis in human obesity.

The mobilization of fat stored in adipose tissue is mediated by hormone-sensitive lipase (HSL) and the recently characterized adipose triglyceride lipase (ATGL), yet their relative importance in lipolysis is unknown. We show that a novel potent inhibitor of HSL does not inhibit other lipases. The compound counteracted catecholamine-stimulated lipolysis in mouse adipocytes and had no effect on residual triglyceride hydrolysis and lipolysis in HSL-null mice. In human adipocytes, catecholamine- and natriuretic peptide-induced lipolysis were completely blunted by the HSL inhibitor. When fat cells were not stimulated, glycerol but not fatty acid release was inhibited. HSL and ATGL mRNA levels increased concomitantly during adipocyte differentiation. Abundance of the two transcripts in human adipose tissue was highly correlated in habitual dietary conditions and during a hypocaloric diet, suggesting common regulatory mechanisms for the two genes. Comparison of obese and nonobese subjects showed that obesity was associated with a decrease in catecholamine-induced lipolysis and HSL expression in mature fat cells and in differentiated preadipocytes. In conclusion, HSL is the major lipase for catecholamine- and natriuretic peptide-stimulated lipolysis, whereas ATGL mediates the hydrolysis of triglycerides during basal lipolysis. Decreased catecholamine-induced lipolysis and low HSL expression constitute a possibly primary defect in obesity.

Diabetes. 2005 Nov;54(11):3190-7

Citrange fruit extracts alleviate obesity-associated metabolic disorder in high-fat diet-induced obese C57BL/6 mouse.

Obesity is becoming one of the global epidemics of the 21st century. In this study, the effects of citrange (Citrus sinensis × Poncirus trifoliata) fruit extracts in high-fat (HF) diet-induced obesity mice were studied. Female C57BL/6 mice were fed respectively a chow diet (control), an HF diet, HF diet supplemented with 1% w/w citrange peel extract (CPE) or 1% w/w citrange flesh and seed extract (CFSE) for 8 weeks. Our results showed that both CPE and CFSE regulated the glucose metabolic disorders of obese mice. In CPE and CFSE-treated groups, the body weight gain, blood glucose, serum total cholesterol (TC) and low density lipoprotein cholesterol (LDL-c) levels were significantly (p<0.05) reduced relative to those in the HF group. To explore the mechanisms of action of CPE and CFSE on the metabolism of glucose and lipid, related genes’ expressions in liver were assayed. In liver tissue, the expression level of peroxisome proliferator-activated receptor g (PPARg) and its target genes were down-regulated by CPE and CFSE supplementation as revealed by qPCR tests. In addition, both CPE and CFSE decreased the expression level of liver X receptor (LXR) a and b, which are involved in lipid and glucose metabolism. Taken together, these results suggest that CPE and CFSE administration could ameliorate obesity and related metabolic disorders in HF diet-induced obesity mice probably through the inhibition of PPARg and LXRs gene expressions.

Int J Mol Sci. 2013 Dec 5;14(12):23736-50

Blood orange juice inhibits fat accumulation in mice.

OBJECTIVE: To analyze the effect of the juice obtained from two varieties of sweet orange (Citrus sinensis L. Osbeck), Moro (a blood orange) and Navelina (a blond orange), on fat accumulation in mice fed a standard or a high-fat diet (HFD). METHODS: Obesity was induced in male C57/Bl6 mice by feeding a HFD. Moro and Navelina juices were provided instead of water. The effect of an anthocyanin-enriched extract from Moro oranges or purified cyanidin-3-glucoside (C3G) was also analyzed. Body weight and food intake were measured regularly over a 12-week period. The adipose pads were weighted and analyzed histologically; total RNA was also isolated for microarray analysis. RESULTS: Dietary supplementation of Moro juice, but not Navelina juice significantly reduced body weight gain and fat accumulation regardless of the increased energy intake because of sugar content. Furthermore, mice drinking Moro juice were resistant to HFD-induced obesity with no alterations in food intake. Only the anthocyanin extract, but not the purified C3G, slightly affected fat accumulation. High-throughput gene expression analysis of fat tissues confirmed that Moro juice could entirely rescue the high fat-induced transcriptional reprogramming. CONCLUSION: Moro juice anti-obesity effect on fat accumulation cannot be explained only by its anthocyanin content. Our findings suggest that multiple components present in the Moro orange juice might act synergistically to inhibit fat accumulation.

Int J Obes (Lond). 2010 Mar;34(3):578-88

Oxidized LDL

Relationship between urinary 15-F2t-isoprostane and 8-oxodeoxyguanosine levels and breast cancer risk.

To evaluate the role of oxidative stress in breast cancer, we measured urinary levels of 15-F(2t)-isoprostane (15-F(2t)-IsoP) and 8-oxodeoxyguanosine (8-oxodG) in 400 cases and 401 controls, participants of the Long Island Breast Cancer Study Project. We also analyzed the effect of different factors that are associated with oxidative stress and might influence 15-F(2t)-IsoP and 8-oxodG levels. We observed a statistically significant trend in breast cancer risk with increasing quartiles of 15-F(2t)-IsoP levels [odds ratio (OR), 1.25; 95% confidence interval (95% CI), 0.81-1.94; OR, 1.53; 95% CI, 0.99-2.35; OR, 1.88; 95% CI, 1.23-2.88, for the 2nd, 3rd, and 4th quartile relative to the lowest quartile, respectively; P(trend) = 0.002]. Although it is possible that increased levels may reflect the stress associated with recent treatment, the positive association was also observed when the analyses were restricted to case women for whom chemotherapy and radiation therapy had not yet been initiated at the time of the urine collection. The association with the highest quartile compared with lowest quartile of 15-F(2t)-IsoP was similar across strata of age, physical activity, fruit and vegetable intake, alcohol intake, cigarette smoking, body mass index, and menopausal status. We did not observe any association of breast cancer risk with 8-oxodG levels, but when cases with radiation treatment were removed from the analysis, a significant inverse trend (P = 0.04) was observed. Among controls, levels of 15-F(2t)-IsoP were higher among current cigarette smokers but did not differ by the amount of physical activity, fruit and vegetable intake, alcohol intake, body mass index, and menopausal status. Among controls, levels of 8-oxodG were higher among postmenopausal women and current and former cigarette smokers but did not differ by the other factors. In summary, our results suggest that urinary markers of lipid peroxidation and oxidative DNA damage may be associated with breast cancer risk.

Cancer Epidemiol Biomarkers Prev. 2006 Apr;15(4):639-44

Association of plasma micro-nutrient levels and urinary isoprostane with risk of lung cancer: the multiethnic cohort study.

Although smoking is the primary risk factor for lung cancer, there is evidence to suggest that fruit and vegetable intake are important cofactors. The present case-control study, nested within the Multiethnic Cohort Study, examined the associations of biomarkers of fruit and vegetable intake (individual plasma micronutrient levels), serum selenium, and a urinary biomarker for total lipid peroxidation with lung cancer risk. Two hundred seven incident cases were matched to 414 controls on age, sex, ethnicity, study location (Hawaii or California), smoking status, date/time of collection, and hours of fasting. We measured prediagnositic circulating levels of individual tocopherols and carotenoids, retinol, and serum selenium, and urinary 15-isoprostane F(2t). Conditional logistic regression was used to compute odds ratios (OR) and 95% confidence intervals (CI). For men, strong reductions in risk were seen with increasing tertiles of each plasma carotenoid, with the ORs for the third tertile, compared with the first tertile, ranging from 0.24 to 0.45 (P(trends), 0.002-0.04). No associations were found among women for carotenoids or among either sex for tocopherols, selenium, and retinol. A doubling in risk was seen for men in the second and third tertiles, compared with the first tertile of urinary 15-isoprostane F(2t) (OR, 2.31; 95% CI, 1.02-5.25; and OR, 2.16; 95% CI, 0.98-4.78). This study supports the previously observed association between circulating carotenoids and lung cancer risk in men, and adds to the limited literature regarding urinary 15-isoprostane F(2t) as a marker of cancer risk. Future research examining the possible relationship between isoprostanes and lung cancer is warranted.

Cancer Epidemiol Biomarkers Prev. 2009 Jul;18(7):1962-70

Effects of anaerobic exercise and aerobic exercise on biomarkers of oxidative stress.

OBJECTIVES: In addition to having health-promoting effects, exercise is considered to induce oxidative stress. To clarify whether increased oxygen consumption during exercise induces oxidative stress, we investigated the effects of aerobic exercise and anaerobic exercise on a series of oxidative damage markers. METHODS: One group of subjects performed aerobic exercise and another group performed anaerobic exercise with similar workloads, but with different levels of oxygen consumption. Blood and urine samples were collected before, immediately after, and 3, 9, and 24 h after exercise. Serum uric acid (UA) and creatine phosphokinase were evaluated. As markers of oxidative damage to lipids, proteins and DNA, we evaluated serum 4-hydroxy-2-nonenal, urinary F(2)-isoprostanes, serum protein carbonyls, and leukocyte 8-hydroxydeoxyguanosine. RESULTS: Oxygen consumption was significantly greater during aerobic exercise. Although UA level increased immediately after aerobic exercise and decreased thereafter, UA level did not change after anaerobic exercise. The two types of exercise had significantly different effects on the change in UA level. After anaerobic exercise, the levels of 8-hydroxydeoxyguanosine and 4-hydroxy-2-nonenal significantly increased at 24 h and 3 h, respectively. The levels of creatine phosphokinase and F(2)-isoprostanes decreased after exercise. The two types of exercise caused no apparent significant differences in the levels of these biomarkers. CONCLUSION: The findings suggest that similar workloads of anaerobic exercise and aerobic exercise induce reactive oxygen species (ROS) differently: aerobic exercise seems to initially generate more ROS, whereas anaerobic exercise may induce prolonged ROS generation. Although more oxygen was consumed during aerobic exercise, the generated ROS did not induce significant oxidative damage. Oxygen consumption per se may not be the major cause of exercise-induced oxidative damage.

Environ Health Prev Med. 2007 Sep;12(5):202-8

Vitamin E dietary supplementation significantly affects multiple risk factors for cardiovascular disease in baboons.

BACKGROUND: Oxidative stress is a widely accepted risk factor for cardiovascular disease (CVD), but the CVD benefit of dietary antioxidants, such as vitamin E, is controversial. OBJECTIVE: Therefore, we have investigated, in the baboon model, the effects of dietary vitamin E supplementation on risk factors for CVD. DESIGN: Pedigreed baboons (n = 251) were fed 2 atherogenic diets, high in fat and cholesterol, that differed in vitamin E concentrations. After 7 wk on each diet, blood samples were taken, and a panel of CVD risk factor traits (ie, indicators of lipoprotein metabolism and oxidative stress) were measured. RESULTS: Vitamin E supplementation caused significantly higher total antioxidant status (TAS) and lower oxidized LDL as expected. In addition, vitamin E caused 2 paradoxical effects on HDL metabolism: higher apolipoprotein A-I (apo A-I) concentrations and lower HDL sizes. We calculated a difference (Delta) variable for each trait as the value on the high-vitamin E diet minus that on the low-vitamin E diet and determined that several HDL concentration Delta variables were significantly correlated with Delta TAS, but only one, Delta apo A-I, was independently correlated. Genetic analyses showed that 2 Delta variables, Delta paraoxonase and Delta HDL(2), were significantly heritable, but that neither Delta TAS nor Delta apo A-I were heritable. CONCLUSIONS: Thus, our data show that dietary vitamin E improves TAS and LDL quality. They also show 2 apparently paradoxical effects on HDL metabolism: lower HDL(2), which is mediated by genes, and higher apo A-I, which is not. These effects have contrasting associations with CVD risk and may help account for the mixed results from clinical trials of dietary
vitamin E.

Am J Clin Nutr. 2007 Sep;86(3):597-603

Sesame lignans enhance antioxidant activity of vitamin E in lipid peroxidation systems.

The antioxidant properties of sesame lignans (sesamol, sesamin and sesamolin) were evaluated in comparison to tocols (alpha- and gamma-tocopherols and alpha-tocotrienol) and butylated hydroxytoluene (BHT) using the following in vitro lipid peroxidation systems: (i) rat liver microsomes and cumene hydroperoxide (CumOOH)/Fe2+-ADP-NADPH (enzymatic) or (ii) rat liver mitochondria and Fe2+-ascorbate (nonenzymatic) systems. Sesamol containing a free phenolic group inhibited lipid peroxidation in both the systems whereas sesamin and sesamolin having methylenedioxy groups were effective only in the microsomal system. Since detoxifying enzymes are localized in microsomes, the inhibitory effects of sesamin and sesamolin observed in the microsomal system may be attributed to their metabolites. However, the inhibitory effects of lignans were lower than tocols and BHT. Combination of individual lignans and tocopherols (alpha, gamma) or alpha-tocotrienol showed higher inhibitory effects than the sum of individual inhibitions in CumOOH and Fe2+-ascorbate systems suggesting synergistic interactions. The time course of CumOOH-mediated lipid peroxidation showed a lag period and a decreased rate of thiobarbituric acid reactive product formation in the presence of individual lignans in combination with alpha-tocopherol suggesting recycling of alpha-tocopherol.

Mol Cell Biochem. 2004 Jul;262(1-2):195-202

L-Carnitine supplementation reduces oxidized LDL cholesterol in patients with diabetes.

BACKGROUND: Patients with type 2 diabetes are under high oxidative stress, and levels of hyperglycemia correlate strongly with levels of LDL oxidation. Carnitine favorably modulates oxidative stress. OBJECTIVE: This objective of this study was to evaluate the efficacy of L-carnitine on the reduction of oxidized LDL cholesterol in patients with type 2 diabetes. DESIGN: Eighty-one patients with diabetes were randomly assigned to 1 of 2 treatment groups for 3 mo. The 2 groups received either 2 g L-carnitine once daily (n = 41) or placebo (n = 40). The following variables were assessed at baseline, after washout, and at 1, 2, and 3 mo of treatment: body mass index, fasting plasma glucose, glycosylated hemoglobin, total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, apolipoprotein A1, apolipoprotein B-100, oxidized LDL cholesterol, thiobarbituric acid-reactive substances, and conjugated dienes. RESULTS: At the end of the study period, the L-carnitine-treated patients showed significant improvements compared with the placebo group in the following markers: oxidized LDL levels decreased by 15.1 compared with 3.0 U/L (P < 0.001); LDL cholesterol decreased by 0.45 compared with 0.16 mmol/L (P < 0.05); triglycerides decreased by 1.02 compared with 0.09 mmol/L (P < 0.001); apolipoprotein A1 concentrations decreased by 0.12 compared with 0.03 mg/dL (P < 0.05); apolipoprotein B-100 concentrations decreased by 0.13 compared with 0.04 mg/dL (P < 0.05); thiobarbituric acid-reactive substance concentrations decreased by 1.92 compared with 0.05 (P < 0.001), and conjugated diene concentrations decreased by 0.72 compared with 0.11 in the placebo group (P < 0.001). CONCLUSION: Our study indicates that oral administration of L-carnitine reduces oxidized LDL cholesterol levels in patients with type 2 diabetes.

Am J Clin Nutr. 2009 Jan;89(1):71-6