Life Extension Magazine®

Issue: May 2009

Vitamin C

Scientifically reviewed by: Dr. Gary Gonzalez, MD, on January 2021.

Reduction of serum ubiquinol-10 and ubiquinone-10 levels by atorvastatin in hypercholesterolemic patients.

Reduction of serum cholesterol levels with statin therapy decreases the risk of coronary heart disease. Inhibition of HMG-CoA reductase by statin results in decreased synthesis of cholesterol and other products downstream of mevalonate, which may produce adverse effects in statin therapy. We studied the reductions of serum ubiquinol-10 and ubiquinone-10 levels in hypercholesterolemic patients treated with atorvastatin. Fourteen patients were treated with 10 mg/day of atorvastatin, and serum lipid, ubiquinol-10 and ubiquinone-10 levels were measured before and after 8 weeks of treatment. Serum total cholesterol and LDL-cholesterol levels decreased significantly. All patients showed definite reductions of serum ubiquinol-10 and ubiquinone-10 levels, and mean levels of serum ubiquinol-10 and ubiquinone-10 levels decreased significantly from 0.81 +/- 0.21 to 0.46 +/- 0.10 microg/ml (p < 0.0001), and from 0.10 +/- 0.06 to 0.06 +/- 0.02 microg/ml (p = 0.0008), respectively. Percent reductions of ubiquinol-10 and those of total cholesterol showed a positive correlation (r = 0.627, p = 0.0165). As atorvastatin reduces serum ubiquinol-10 as well as serum cholesterol levels in all patients, it is imperative that physicians are forewarned about the risks associated with ubiquinol-10 depletion.

J Atheroscler Thromb. 2005;12(2):111-9

Efficacy and safety of extended-release niacin alone or with atorvastatin for lipid profile modification.

OBJECTIVE: To evaluate the efficacy and safety of extended-release niacin (niacin ER) either alone or in combination with atorvastatin for the lipid profile modification in the patients with coronary heart disease (CHD) and its equivalents. METHODS: One hundred and ten patients with CHD and its equivalents with serum total cholesterol (TC) > or = 3.5 mmol/L were randomly assigned into three treatment groups: (1) atorvastatin group (n = 38), receiving atorvastatin 10 mg/d for 8 weeks; (2) niacin ER group (n = 38), given niacin ER 500 mg/d for 4 weeks and then 1000 mg/d for 4 weeks; (3) combination treatment group (n = 34), treated with atorvastatin (10 mg/d) plus niacin ER, with the dose initiating from 500 mg/d, and increasing to 1,000 mg/d after 4 weeks, for 8 weeks. The serums lipid profiles and adverse effects were assessed in all the patients before treatment, and 4 and 8 weeks after treatment. RESULTS: (1) After 8 weeks of treatment, the serum level of triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) were reduced by 30% and 16% respectively in the niacin ER group compared with the baseline values (both P < 0.05). After 8 weeks, the TC, low-density lipoprotein cholesterol (LDL-C), and TG in the atorvastatin group decreased by 19%, 26%, and 17% respectively compared with the baseline values (all P < 0.05). Combination treatment decreased the TC, LDL-C, and TG levels by 28%, 38%, and 39% respectively, and increased the HDL-C level by 23% (all P < 0.05). The improvement in TC and LDL-C achieved by combination treatment was superior to treatment of atorvastatin alone and treatment of niacin ER alone (all P < 0.05). (2) The rate of achieving the LDL-C goal of The National Cholesterol Education Program (NCEP) in Adult Treatment Panel III (ATP III) in the combination therapy group was 73.5%, significantly higher than those of the atorvastatin and niacin groups (47.7% and 42.1% respectively, both P < 0.05). (3) Adverse effect, such as flushing (15.8%) and gastrointestinal symptoms (23.7%) were found in the niacin ER group, however, no more adverse effects were found in the combination therapy group. There were no serious adverse events in all groups. CONCLUSION: Niacin ER has a favorable effect in modulating the blood lipid profile, especially in reducing TG and elevating HDL-C. Combined statin with niacin may produce a more global and effective improvement in lipid blood levels than monotherapy and is generally safe and well tolerable.

Zhonghua Yi Xue Za Zhi. 2006 Sep 12;86(34):2399-403

Effect of glucomannan on plasma lipid and glucose concentrations, body weight, and blood pressure: systematic review and meta-analysis.

BACKGROUND: Several clinical trials have investigated the impact of glucomannan on plasma lipids, body weight, fasting blood glucose (FBG), and blood pressure (BP), but have yielded conflicting results and had only modest sample sizes. OBJECTIVE: The objective was to perform a meta-analysis of randomized controlled trials of glucomannan to better characterize its impact on plasma lipids, FBG, body weight, and BP. DESIGN: A systematic literature search of MEDLINE, EMBASE, CINAHL, Web of Science, the Cochrane Library, and the Natural Medicines Comprehensive Database was conducted from the earliest possible date through November 2007. A random-effects model was used to calculate the weighted mean difference (WMD) and 95% CIs as the difference between the mean for the glucomannan and control groups. Standard methods for assessing statistical heterogeneity and publication bias were used. RESULTS: Fourteen studies (n = 531) met the inclusion criteria. The use of glucomannan significantly lowered total cholesterol [weighted mean difference (WMD): -19.28 mg/dL; 95% CI: -24.30, -14.26], LDL cholesterol (WMD: -15.99 mg/dL; 95% CI: -21.31, -10.67), triglycerides (WMD: -11.08 mg/dL; 95% CI: -22.07, -0.09), body weight (WMD: -0.79 kg; 95% CI: -1.53, -0.05), and FBG (WMD: -7.44 mg/dL; 95% CI: -14.16, -0.72). The use of glucomannan did not appear to significantly alter any other study endpoints. Pediatric patients, patients receiving dietary modification, and patients with impaired glucose metabolism did not benefit from glucomannan to the same degree. CONCLUSIONS: Glucomannan appears to beneficially affect total cholesterol, LDL cholesterol, triglycerides, body weight, and FBG, but not HDL cholesterol or BP.

Am J Clin Nutr. 2008 Oct;88(4):1167-75

Persistent and remodeling hepatic preneoplastic lesions present differences in cell proliferation and apoptosis, as well as in p53, Bcl-2 and NF-kappaB pathways.

During rat hepatocarcinogenesis preneoplastic lesions (PNL) emerge which may persist (pPNL) and be sites of progress to cancer or suffer remodeling (rPNL) tending to disappear. Cellular and molecular mechanisms involved in both phenotypes are not sufficiently elucidated. pPNL and rPNL cellular proliferation and apoptosis were evaluated in rats submitted to the resistant hepatocyte (RH) model, and an adjusted growth index (AGI) was established. p53, Bcl-2, and NF-kappaB p65 subunit expression was evaluated by immunohistochemistry in pPNL and rPNL. p65 expression and NF-kappaB activation was evaluated by Western blot assays in whole livers. A lower number of BrdU-stained hepatocyte nuclei/mm(2) and higher number of apoptotic bodies (AB) per mm(2) were observed in remodeling compared to pPNL. Cytoplasmic p53 accumulation is related to increased hepatocarcinoma malignancy. We observed that 71.3% pPNL and 25.4% rPNL (P < 0.05) presented p53 staining in the cytoplasm. Similarly, 67.7% pPNL and 23.1 % rPNL (P < 0.05) presented increased Bcl-2 staining. Thirty-two percent pPNL and 15.6% rPNL (P < 0.05) presented p65 staining. Compared to normal rats, increase (P < 0.05) of hepatic p65 expression and NF-kappaB activation in rats submitted to the RH model was observed. In agreement to previous studies hepatic pPNL and rPNL differ regarding cell proliferation and apoptosis. Moreover, persistence and remodeling involve differences in p53, Bcl-2, and NF-kappaB pathways. These data point to molecular pathways that may direct preneoplastic lesions to spontaneously regress or to progress to cancer.

J Cell Biochem. 2008 Feb 1;103(2):538-46

Inhibition of Irvingia gabonensis seed extract (OB131) on adipogenesis as mediated via down regulation of the PPARgamma and Leptin genes and up-regulation of the adiponectin gene.

BACKGROUND: Endeavors to manage obesity have been heavily reliant on controlling energy intake and expenditure equilibrium, but have failed to curtail the overweight and obesity epidemic. This dynamic equilibrium is more complex than originally postulated and is influenced by lifestyle, calorie and nutrient intake, reward cravings and satiation, energy metabolism, stress response capabilities, immune metabolism and genetics. Fat metabolism is an important indicator of how efficiently and to what extent these factors are competently integrating. We investigated whether an Irvingia gabonensis seed extract (IGOB131) would provide a more beneficial comprehensive approach influencing multiple mechanisms and specifically PPAR gamma, leptin and adiponectin gene expressions, important in anti-obesity strategies. METHODS: Using murine 3T3-L1 adipocytes as a model for adipose cell biology research, the effects of IGOB131 were investigated on PPAR gamma, adiponectin, and leptin. These adipocytes were harvested 8 days after the initiation of differentiation and treated with 0 to 250 microM of IGOB131 for 12 and 24 h at 37 degree C in a humidified 5 percent CO2 incubator. The relative expression of PPAR gamma, adiponectin, and leptin in 3T3-L1 adipocytes was quantified densitometrically using the software LabWorks 4.5, and calculated according to the reference bands of beta-actin. RESULTS: The IGOB131 significantly inhibited adipogenesis in adipocytes. The effect appears to be mediated through the down-regulated expression of adipogenic transcription factors (PPAR gamma) [P less than 0.05] and adipocyte-specific proteins (leptin) [P less than 0.05], and by up-regulated expression of adiponectin [P less than 0.05]. CONCLUSION: IGOB131 may play an important multifaceted role in the control of adipogenesis and have further implications in in-vivo anti obesity effects by targeting the PPAR gamma gene, a known contributory factor to obesity in humans.

Lipids Health Dis. 2008 Nov 13;7:44

Rosuvastatin to prevent vascular events in men and women with elevated C-reactive protein.

BACKGROUND: Increased levels of the inflammatory biomarker high-sensitivity C-reactive protein predict cardiovascular events. Since statins lower levels of high-sensitivity C-reactive protein as well as cholesterol, we hypothesized that people with elevated high-sensitivity C-reactive protein levels but without hyperlipidemia might benefit from statin treatment. METHODS: We randomly assigned 17,802 apparently healthy men and women with low-density lipoprotein (LDL) cholesterol levels of less than 130 mg per deciliter (3.4 mmol per liter) and high-sensitivity C-reactive protein levels of 2.0 mg per liter or higher to rosuvastatin, 20 mg daily, or placebo and followed them for the occurrence of the combined primary end point of myocardial infarction, stroke, arterial revascularization, hospitalization for unstable angina, or death from cardiovascular causes. RESULTS: The trial was stopped after a median follow-up of 1.9 years (maximum, 5.0). Rosuvastatin reduced LDL cholesterol levels by 50% and high-sensitivity C-reactive protein levels by 37%. The rates of the primary end point were 0.77 and 1.36 per 100 person-years of follow-up in the rosuvastatin and placebo groups, respectively (hazard ratio for rosuvastatin, 0.56; 95% confidence interval [CI], 0.46 to 0.69; P<0.00001), with corresponding rates of 0.17 and 0.37 for myocardial infarction (hazard ratio, 0.46; 95% CI, 0.30 to 0.70; P=0.0002), 0.18 and 0.34 for stroke (hazard ratio, 0.52; 95% CI, 0.34 to 0.79; P=0.002), 0.41 and 0.77 for revascularization or unstable angina (hazard ratio, 0.53; 95% CI, 0.40 to 0.70; P<0.00001), 0.45 and 0.85 for the combined end point of myocardial infarction, stroke, or death from cardiovascular causes (hazard ratio, 0.53; 95% CI, 0.40 to 0.69; P<0.00001), and 1.00 and 1.25 for death from any cause (hazard ratio, 0.80; 95% CI, 0.67 to 0.97; P=0.02). Consistent effects were observed in all subgroups evaluated. The rosuvastatin group did not have a significant increase in myopathy or cancer but did have a higher incidence of physician-reported diabetes. CONCLUSIONS: In this trial of apparently healthy persons without hyperlipidemia but with elevated high-sensitivity C-reactive protein levels, rosuvastatin significantly reduced the incidence of major cardiovascular events.

N Engl J Med. 2008 Nov 20;359(21):2195-207

Osteoclast inhibitory effects of vitamin K2 alone or in combination with etidronate or risedronate in patients with rheumatoid arthritis: 2-year results.

OBJECTIVE: To investigate the effects of vitamin K2 (Vit K2) alone or in combination with etidronate and risedronate on bone loss, osteoclast induction, and inflammation in patients with rheumatoid arthritis (RA). METHODS: Subjects comprised 79 patients with RA who were receiving prednisolone, divided into 3 groups: Group K, Vit K2 alone; Group KE, Vit K2 plus etidronate; and Group KR, Vit K2 plus risedronate. During a 24-month treatment and followup period, levels of N-terminal telopeptide of type I collagen (NTx) and bone alkaline phosphatase were measured. Bone mineral density (BMD) of the 3 groups was measured using dual-energy x-ray absorptiometry. Damage score to fingers on radiographic findings were measured according to the Larsen method. Serum levels of receptor activator of nuclear factor-kappaB ligand (RANKL) and osteoprotegerin (OPG) were measured. RESULTS: Falls in rate of change of BMD decreased after 18 months in groups KR and KE. Larsen damage scores indicated a significant difference between Group KE and other groups. Significant decreases in serum NTx were observed in groups KE and KR at all timepoints, but not in Group K. Levels of RANKL decreased significantly in all 3 groups. CONCLUSION: Vit K2 alone or in combination with bisphosphonates for treatment of osteoporosis in patients with RA may inhibit osteoclast induction via decreases in levels of RANKL.

J Rheumatol. 2008 Mar;35(3):407-13

25-hydroxyvitamin D and risk of myocardial infarction in men: a prospective study.

BACKGROUND: Vitamin D deficiency may be involved in the development of atherosclerosis and coronary heart disease in humans. METHODS: We assessed prospectively whether plasma 25-hydroxyvitamin D (25[OH]D) concentrations are associated with risk of coronary heart disease. A nested case-control study was conducted in 18,225 men in the Health Professionals Follow-up Study; the men were aged 40 to 75 years and were free of diagnosed cardiovascular disease at blood collection. The blood samples were returned between April 1, 1993, and November 30, 1999; 99% were received between April 1, 1993, and November 30, 1995. During 10 years of follow-up, 454 men developed nonfatal myocardial infarction or fatal coronary heart disease. Using risk set sampling, controls (n = 900) were selected in a 2:1 ratio and matched for age, date of blood collection, and smoking status. RESULTS: After adjustment for matched variables, men deficient in 25(OH)D (<or=15 ng/mL [to convert to nanomoles per liter, multiply by 2.496]) were at increased risk for MI compared with those considered to be sufficient in 25(OH)D (>or=30 ng/mL) (relative risk [RR], 2.42; 95% confidence interval [CI], 1.53-3.84; P < .001 for trend). After additional adjustment for family history of myocardial infarction, body mass index, alcohol consumption, physical activity, history of diabetes mellitus and hypertension, ethnicity, region, marine omega-3 intake, low- and high-density lipoprotein cholesterol levels, and triglyceride levels, this relationship remained significant (RR, 2.09; 95% CI, 1.24-3.54; P = .02 for trend). Even men with intermediate 25(OH)D levels were at elevated risk relative to those with sufficient 25(OH)D levels (22.6-29.9 ng/mL: RR, 1.60 [95% CI, 1.10-2.32]; and 15.0-22.5 ng/mL: RR, 1.43 [95% CI, 0.96-2.13], respectively). CONCLUSION: Low levels of 25(OH)D are associated with higher risk of myocardial infarction in a graded manner, even after controlling for factors known to be associated with coronary artery disease.

Arch Intern Med. 2008 Jun 9;168(11):1174-80

Independent association of low serum 25-hydroxyvitamin d and 1,25-dihydroxyvitamin d levels with all-cause and cardiovascular mortality.

BACKGROUND: In cross-sectional studies, low serum levels of 25-hydroxyvitamin D are associated with higher prevalence of cardiovascular risk factors and disease. This study aimed to determine whether endogenous 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels are related to all-cause and cardiovascular mortality. METHODS: Prospective cohort study of 3,258 consecutive male and female patients (mean [SD] age, 62 [10] years) scheduled for coronary angiography at a single tertiary center. We formed quartiles according to 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels within each month of blood drawings. The main outcome measures were all-cause and cardiovascular deaths. RESULTS: During a median follow-up period of 7.7 years, 737 patients (22.6%) died, including 463 deaths from cardiovascular causes. Multivariate-adjusted hazard ratios (HRs) for patients in the lower two 25-hydroxyvitamin D quartiles (median, 7.6 and 13.3 ng/mL [to convert 25-hydroxyvitamin D levels to nanomoles per liter, multiply by 2.496]) were higher for all-cause mortality (HR, 2.08; 95% confidence interval [CI], 1.60-2.70; and HR, 1.53; 95% CI, 1.17-2.01; respectively) and for cardiovascular mortality (HR, 2.22; 95% CI, 1.57-3.13; and HR, 1.82; 95% CI, 1.29-2.58; respectively) compared with patients in the highest 25-hydroxyvitamin D quartile (median, 28.4 ng/mL). Similar results were obtained for patients in the lowest 1,25-dihydroxyvitamin D quartile. These effects were independent of coronary artery disease, physical activity level, Charlson Comorbidity Index, variables of mineral metabolism, and New York Heart Association functional class. Low 25-hydroxyvitamin D levels were significantly correlated with variables of inflammation (C-reactive protein and interleukin 6 levels), oxidative burden (serum phospholipid and glutathione levels), and cell adhesion (vascular cell adhesion molecule 1 and intercellular adhesion molecule 1 levels). CONCLUSIONS: Low 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels are independently associated with all-cause and cardiovascular mortality. A causal relationship has yet to be proved by intervention trials using vitamin D.

Arch Intern Med. 2008 Jun 23;168(12):1340-9

Orlistat in the treatment of overweight or obese Chinese patients with newly diagnosed Type 2 diabetes.

AIMS: Orlistat promotes weight loss in overweight and obese patients with Type 2 diabetes receiving hypoglycaemic treatment, but has not been investigated in patients with newly diagnosed and previously untreated Type 2 diabetes. We evaluated the efficacy of 24 weeks’ treatment with orlistat, combined with a mildly reduced-calorie diet, on weight loss and glycaemic control in overweight and obese patients with newly diagnosed and previously untreated Type 2 diabetes. METHODS: A total of 249 Chinese patients (body mass index 25-40 kg/m2) with recently diagnosed Type 2 diabetes were randomized to placebo (n=124) or orlistat 120 mg (n=125) three times daily; all patients followed a mildly reduced-calorie diet. Patients had HbA1c 6.5-8.5% (mean 7.3%) and had never received any glucose-lowering medication. RESULTS: Orlistat-treated patients achieved significantly greater weight loss at the study end than placebo-treated patients (-5.4 vs. -2.4 kg; P<0.0001). More orlistat than placebo patients lost>or=5% (60.5 vs. 26.8%; P<0.0001) and >or=10% of their body weight (20.2 vs. 4.9%; P=0.0002). A significantly greater decrease in HbA(1c) from baseline was obtained with orlistat than placebo (-1.0 vs. -0.6%; P=0.0008). Orlistat-treated patients achieved a significantly greater decrease in fasting plasma glucose (-1.3 vs. -0.5 mmol/l; P=0.0003) and in the 2-h oral glucose tolerance test (-4.1 vs. -1.4 mmol/l; P<0.0001) than placebo recipients. Also, more orlistat- than placebo-treated patients improved from diabetic status to normal or impaired glucose tolerance (44.3 vs. 32.5%; P=0.0763) after 24 weeks. Orlistat also produced improvements in lipid profiles and waist circumference. CONCLUSIONS: In combination with a mildly reduced-calorie diet, orlistat significantly reduces body weight, and improves glycaemic control and several cardiovascular risk factors in overweight and obese Chinese patients with newly diagnosed Type 2 diabetes.

Diabet Med. 2005 Dec;22(12):1737-43

Endogenous sex hormones and C-reactive protein in healthy postmenopausal women.

BACKGROUND: Oral oestrogen replacement therapy increases levels of C-reactive protein (CRP). CRP is an established strong predictor of cardiovascular events. It is unknown whether endogenous oestrogen levels are associated with CRP. We therefore studied the relationship between endogenous sex hormones and CRP in healthy postmenopausal women emphasizing the role of body composition as peripheral fat is both a main source of oestrogen production after menopause and an endocrine tissue with inflammatory activities. SUBJECTS AND METHODS: The study population comprised 889 women participating in the PROSPECT study, an ongoing population-based cohort study. Information on risk factors was collected by questionnaires and clinical examination. Endogenous sex hormone levels and CRP were measured with double antibody radio immuno assay (RIA) from fasting plasma samples. In this cross-sectional study, associations between risk factors and lnCRP were studied using linear regression models. RESULTS: Increases in oestrone and free oestradiol levels and the free androgen index were related to an increase in lnCRP of 1.19, 1.23 and 1.21 mg dL(-1) respectively. Body mass index (BMI), waist circumference and physical activity were strongly related to CRP levels, independent of age and other cardiovascular risk factors. Levels of all sex steroids but dehydroepiandrostenedione decreased with age. In age-adjusted analyses, an increase in waist circumference or BMI by one quartile was associated with a 1.28-fold and 1.26-fold increase in CRP. The relationship between endogenous hormones and CRP was modestly attenuated but remained highly significant after adjustment for body composition, physical activity and other traditional cardiovascular risk factors. CONCLUSIONS: Our findings show that in postmenopausal women high levels of endogenous oestrogenic and androgenic sex steroids coincide with high CRP levels. This was only explained in part by markers of body composition or intra-abdominal fat.

J Intern Med. 2008 Sep;264(3):245-53

Advanced age is associated with endothelial dysfunction in healthy elderly subjects.

BACKGROUND: Aging is associated with an increased risk for atherosclerosis in which endothelial dysfunction is an early marker. OBJECTIVE: The purpose of this study was to determine if endothelial function is altered with increasing age in healthy subjects. METHOD: The study population consisted of 30 elderly and 36 younger subjects free from major cardiovascular risk factors. Transthoracic echocardiography was performed for each subject to rule out structural heart disease. Endothelial function was evaluated by flow-mediated dilation (FMD) of the brachial artery via ultrasound. RESULTS: Baseline characteristics of the elderly and the younger group were similar, except for age (mean age: 71.3 +/- 5.8 vs. 26.5 +/- 7.2). Transthoracic echocardiography was normal in all subjects. FMD of the elderly group was significantly lower than the younger group (7.9 +/- 3.1 in the elderly, 10.8 +/- 1.9 in the younger group, p < 0.001). A negative relationship was found between FMD and age (r = -0.528, p < 0.001). CONCLUSION: It can be concluded that endothelial function detected by FMD declines with increasing age in healthy human subjects. Advanced age is a predictor of impaired endothelial function.

Gerontology. 2008;54(3):153-6.

How do dietary flavanols improve vascular function? A position paper.

Epidemiological and clinical studies revealed that high-flavanol diet or isolated (-)-epicatechin improves the function of the vascular endothelium, as assessed by flow-mediated dilation, through elevation of bioavailability and bioactivity of NO*. We have demonstrated that exposure of human endothelial cells to (-)-epicatechin elevates the cellular levels of NO* and cyclic GMP and protects against oxidative stress elicited by proinflammatory agonists. (-)-Epicatechin acts like a prodrug, since these effects involve O-methylation of the flavanol and are attributed to apocynin-like inhibition of endothelial NADPH oxidase. Thus, generation of superoxide and peroxynitrite is diminished and, consequently, the cellular NO* level is preserved or augmented. We propose therefore that endothelial NO* metabolism rather than general antioxidant activity is a major target of dietary flavanols and that NADPH oxidase activity is a crucial site of action. Moreover, flavonoid glucuronides appear to serve as plasma transport metabolites to target cells rather than solely as excretion products. Implications for the interpretation of the role of dietary polyphenols for cardiovascular health are discussed.

Arch Biochem Biophys. 2008 Aug 15;476(2):102-6

Oxidation of LDL and its clinical implication.

Oxidative modification of low-density lipoprotein (LDL) is one of the earliest events in atherosclerosis. Oxidized LDL (oxLDL) represents a variety of modification of both lipid and apolipoprotein B (apoB) components by lipid peroxidation. This promotes atherosclerosis through inflammatory and immunologic mechanisms that lead to the formation of macrophage foam cells. Recent findings also suggest that oxLDL forms complexes with beta(2)-glycoprotein I (beta(2)GPI) and/or C-reactive protein (CRP) within atherosclerotic lesions and that these complexes appear in the circulation. Autoantibodies (auto-Abs) against oxLDL/beta(2)GPI complexes occur in patients with systemic lupus erythematosus (SLE) and/or antiphospholipid syndrome (APS). These autoantibodies significantly correlate with arterial thrombosis. IgG auto-Abs having similar specificity emerge spontaneously in NZWxBXSB F1 mice, which generally are considered to be an animal model of APS, and these mice produce a monoclonal IgG auto-Ab (WB-CAL-1) against oxLDL/beta(2)GPI complexes. WB-CAL-1 significantly increased the in vitro uptake of oxLDL/beta(2)GPI complexes by macrophages, which suggests that such IgG auto-Abs are pro-atherogenic. In contrast, IgM anti-oxLDL natural Abs found in the atherosclerosis-prone mice have been proposed to be protective. The presence of such Abs in humans has been documented in many publications but their exact pathophysiological significance remains unclear. In this article, we review recent progress in our understanding of the clinical significance of oxidation of LDL, formation of oxLDL complexes, and Abs in atherosclerotic and/or autoimmune disease.

Autoimmun Rev. 2008 Jul;7(7):558-66

Comparison of lycopene and fluvastatin effects on atherosclerosis induced by a high-fat diet in rabbits.

OBJECTIVE: We evaluated the antiatherogenic effect of lycopene in rabbits fed a high-fat diet. METHODS: Forty adult male rabbits were divided into five groups that were fed a standard diet, a high-fat diet, a high-fat diet plus 4 mg/kg of lycopene, a high-fat diet plus 12 mg/kg of lycopene, and a high-fat diet plus 10 mg/kg of fluvastatin, respectively. Lycopene and fluvastatin were administered intragastrically. The level of serum total cholesterol, total triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, total antioxidant capacity, and malondialdehyde were measured before and after 4 and 8 wk of experimental treatment. In addition, plasma levels of lycopene, oxidized low-density lipoprotein, serum nitric oxide, and interleukin-1 were measured after the experiment. The area of atherosclerotic plaque and pathologic changes of the aorta were evaluated. RESULTS: Compared with the control, levels of total cholesterol, total triacylglycerol, low-density lipoprotein cholesterol, malonaldehyde, oxidized low-density lipoprotein, and interleukin-1 were increased and total antioxidant capacity and nitric oxide were decreased in the animals with a high-fat diet (P < 0.05). Intragastric administration of lycopene counteracted the change in these parameters (P < 0.05). In this case, the data showed that lycopene in the used dose was better than the fluvastatin intervention. Morphologic analysis revealed that lycopene and fluvastatin markedly reduced the formation of atherosclerotic plaques in the aorta compared with the situation in rabbits on a high-fat diet alone. CONCLUSION: Lycopene, like fluvastatin, significantly attenuated atherogenesis in rabbits fed a high-fat diet.

Nutrition. 2008 Oct;24(10):1030-8

General and abdominal adiposity and risk of death in Europe.

BACKGROUND: Previous studies have relied predominantly on the body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) to assess the association of adiposity with the risk of death, but few have examined whether the distribution of body fat contributes to the prediction of death. METHODS: We examined the association of BMI, waist circumference, and waist-to-hip ratio with the risk of death among 359,387 participants from nine countries in the European Prospective Investigation into Cancer and Nutrition (EPIC). We used a Cox regression analysis, with age as the time variable, and stratified the models according to study center and age at recruitment, with further adjustment for educational level, smoking status, alcohol consumption, physical activity, and height. RESULTS: During a mean follow-up of 9.7 years, 14,723 participants died. The lowest risks of death related to BMI were observed at a BMI of 25.3 for men and 24.3 for women. After adjustment for BMI, waist circumference and waist-to-hip ratio were strongly associated with the risk of death. Relative risks among men and women in the highest quintile of waist circumference were 2.05 (95% confidence interval [CI], 1.80 to 2.33) and 1.78 (95% CI, 1.56 to 2.04), respectively, and in the highest quintile of waist-to-hip ratio, the relative risks were 1.68 (95% CI, 1.53 to 1.84) and 1.51 (95% CI, 1.37 to 1.66), respectively. BMI remained significantly associated with the risk of death in models that included waist circumference or waist-to-hip ratio (P<0.001). CONCLUSIONS: These data suggest that both general adiposity and abdominal adiposity are associated with the risk of death and support the use of waist circumference or waist-to-hip ratio in addition to BMI in assessing the risk of death.

N Engl J Med. 2008 Nov 13;359(20):2105-20

Abdominal obesity and the spectrum of global cardiometabolic risks in US adults.

OBJECTIVE: To compare the association of obesity and abdominal obesity with cardiometabolic risk factor burden and global estimated coronary heart disease (CHD) risk among multiethnic US adults. DESIGN: Cross-sectional, survey study. SUBJECTS: A total of 4,456 participants (representing 194.9 million adults) aged 20-79 years in the 2003-2004 National Health and Nutrition Examination Survey (NHANES). MEASUREMENTS: Body mass index (BMI) and waist circumference (WC) measures, CHD risk factors and a 10-year estimated CHD risk based on Framingham algorithms. Obesity was defined as a BMI >or=30 kg/m(2) and abdominal obesity as a WC >88 cm in women and >102 cm in men. High CHD risk status included diabetes, cardiovascular disease (CVD) or a 10-year Framingham risk score of >20%. RESULTS: Overall, abdominal obesity was present in 42.3% of men and 62.5% of women and in 53.6% of whites, 56.9% of blacks and 50.5% of Hispanics (P<0.001 between gender and ethnicity). However, using International Diabetes Federation (IDF)-recommended WC cut points for Hispanics, the prevalence of abdominal obesity was 78.3%. Mean levels of low-density lipoprotein cholesterol (LDL-C), systolic and diastolic blood pressure, fasting glucose and C-reactive protein increased, and high-density lipoprotein cholesterol (HDL-C) decreased (P<0.001) according to BMI and WC categories, although these associations were attenuated in blacks for blood pressure, LDL-C, HDL-C and triglycerides. Of those with high WC, 25-35% had >or=3 cardiometabolic risk factors. High CHD risk among those with high WC was most common in men (27.9%) and non-Hispanic whites (23.9%). Persons with a high vs normal WC, adjusted for age, gender, ethnicity and BMI were more likely to have >or=3 cardiometabolic risk factors (odds ratio (OR)=5.1, 95% confidence interval (CI)=3.9-6.6) and were classified as high CHD risk (OR=1.5, 95% CI=1.1-2.0). CONCLUSION: The association of abdominal obesity with risk factors varies by ethnicity and is independently associated with high CHD risk status, further validating its clinical significance.

Int J Obes (Lond). 2009 Feb;33(2):239-48

“Sick fat,” metabolic disease, and atherosclerosis.

Atherosclerotic coronary heart disease (CHD) is the most common cause of morbidity and mortality among men and women in developed nations. The obesity epidemic contributes to the increasing prevalence of high blood sugar (as may be found in patients with diabetes mellitus and metabolic syndrome), high blood pressure, and dyslipidemia--all CHD risk factors. Metabolic syndrome describes the common clinical finding wherein component CHD risk factors cluster within a single patient, but this term does not identify any unified pathophysiologic process. However, a component of the metabolic syndrome is abdominal obesity, which does reflect an anatomic manifestation of a “common-soil” pathophysiologic process that promotes the onset of CHD risk factors, and thus increases CHD risk. Adiposopathy (“sick fat”) is anatomically characterized by visceral adiposity and adipocyte hypertrophy; it is manifested physiologically by a net increase in release of free fatty acids and by pathogenic adipose tissue metabolic/immune responses that promote metabolic disease and increase CHD risk. Understanding the relation of adiposopathy to CHD risk factors and recognizing the importance of treating both the “cause and effect” of metabolic diseases are critical toward a comprehensive approach in reducing CHD risk. Regarding the “cause,” clinicians and their patients should be diligent regarding appropriate nutritional and lifestyle interventions that may favorably affect health. Regarding the “effect,” clinicians and their patients should be equally diligent toward appropriate pharmaceutical interventions that reduce CHD risk factors when nutritional and lifestyle interventions do not sufficiently achieve desired metabolic treatment goals.

Am J Med. 2009 Jan;122(1 Suppl):S26-37

The role of fat topology in the risk of disease.

Clustering of multiple risk factors such as impaired glucose metabolism, lipid disorders and hypertension has been shown to be the major background of atherosclerotic diseases, and disease entities such as the metabolic syndrome represent a highly atherogenic state. Although these common risks may generally co-exist by accident in one individual, clustering of multiple risk factors in the metabolic syndrome does not occur by accident, and there should be a key player for the syndrome. In 1983, we reported the method for fat analysis using computed tomography scan, which enables us to analyze intra-abdominal visceral adiposity as well as subcutaneous fat. Visceral fat accumulation has been shown to cause impaired glucose metabolism, lipid disorders, and hypertension, and therefore it is considered to be a key player in the metabolic syndrome. To clarify the mechanism by which visceral fat accumulation causes a variety of metabolic and vascular diseases, we studied the molecular characteristics of adipose tissue and adipocytes by investigating expressed genes in visceral and subcutaneous adipocytes and revealed that adipocytes, especially visceral adipocytes, secrete a variety of bioactive substances, the so-called adipocytokines. We showed that visceral fat accumulation causes abnormalities in adipocytokine secretion, such as hypersecretion of plasminogen activator inhibitor 1, which is related to thrombogenic vascular diseases. More importantly, we discovered an important benign adipocytokine named adiponectin, which protects against the development of diabetes mellitus, hypertension, inflammation, and atherosclerotic vascular diseases. Plasma levels of adiponectin decreased in individuals with visceral fat accumulation, and hypoadiponectinemia caused by visceral fat accumulation might be one of the major causes of metabolic syndrome.

Int J Obes (Lond). 2008 Dec;32 Suppl 7:S83-92

Adipokines: inflammation and the pleiotropic role of white adipose tissue.

White adipose tissue is now recognised to be a multifunctional organ; in addition to the central role of lipid storage, it has a major endocrine function secreting several hormones, notably leptin and adiponectin, and a diverse range of other protein factors. These various protein signals have been given the collective name ‘adipocytokines’ or ‘adipokines’. However, since most are neither ‘cytokines’ nor ‘cytokine-like’, it is recommended that the term ‘adipokine’ be universally adopted to describe a protein that is secreted from (and synthesised by) adipocytes. It is suggested that the term is restricted to proteins secreted from adipocytes, excluding signals released only by the other cell types (such as macrophages) in adipose tissue. The adipokinome (which together with lipid moieties released, such as fatty acids and prostaglandins, constitute the secretome of fat cells) includes proteins involved in lipid metabolism, insulin sensitivity, the alternative complement system, vascular haemostasis, blood pressure regulation and angiogenesis, as well as the regulation of energy balance. In addition, there is a growing list of adipokines involved in inflammation (TNFalpha, IL-1beta, IL-6, IL-8, IL-10, transforming growth factor-beta, nerve growth factor) and the acute-phase response (plasminogen activator inhibitor-1, haptoglobin, serum amyloid A). Production of these proteins by adipose tissue is increased in obesity, and raised circulating levels of several acute-phase proteins and inflammatory cytokines has led to the view that the obese are characterised by a state of chronic low-grade inflammation, and that this links causally to insulin resistance and the metabolic syndrome. It is, however, unclear as to the extent to which adipose tissue contributes quantitatively to the elevated circulating levels of these factors in obesity and whether there is a generalised or local state of inflammation. The parsimonious view is that the increased production of inflammatory cytokines and acute-phase proteins by adipose tissue in obesity relates primarily to localised events within the expanding fat depots. It is suggested that these events reflect hypoxia in parts of the growing adipose tissue mass in advance of angiogenesis, and involve the key controller of the cellular response to hypoxia, the transcription factor hypoxia inducible factor-1.

Br J Nutr. 2004 Sep;92(3):347-55

The biology of obesity.

Obesity is a multidisciplinary area, the ‘biology’ of which encompasses: (1) the fundamental mechanisms of energy balance and its regulation; (2) the biological basis for the development of obesity; (3) adipose tissue function; (4) the biological description of the obese state; (5) the pathological consequences of obesity; (6) the physiological basis for treatment strategies. At a mechanistic level, important developments in recent years include the identification of novel neuroendocrine factors in the control of appetite (such as cocaine- and amphetamine-regulated transcript, the orexins, the endocannabinoids) and the discovery of new peripheral signals (such as leptin, ghrelin). Despite the identification of additional uncoupling proteins (UCP2, UCP3), mitochondrial uncoupling in brown adipose tissue through UCP1 remains the only major mechanism for adaptive thermogenesis. White adipose tissue (WAT) has now moved centre stage in energy balance and obesity research, and there are three main reasons: (1) it is the organ which defines obesity; (2) it is the source of a critical endocrine signal in the control of body weight; (3) it secretes a range of diverse protein factors, termed adipokines, some of which are directly implicated in the pathologies associated with obesity. WAT is now recognised as a key endocrine organ, communicating both with the brain and peripheral tissues through the adipokines. Obesity is characterised by mild inflammation, and WAT may be the main locus of the inflammatory state, producing cytokines, chemokines, acute-phase proteins and angiogenic factors. It has been suggested that inflammation in obesity is principally an adaptive response to hypoxia in clusters of adipocytes within the expanding adipose mass.

Proc Nutr Soc. 2005 Feb;64(1):31-8

Obesity and inflammation: lessons from bariatric surgery.

BACKGROUND: Obesity is associated with a series of comorbid conditions that are characterized by an inflammatory state. The purpose of this review is to update knowledge about obesity, adipose tissue, and inflammation. METHODS: Review of the published literature using search terms of adipose, inflammation, obesity, and insulin resistance in combinations. RESULTS: Adipose tissue elaborates proinflammatory cytokines such as interleukin-6 and tumor necrosis factor-alpha, with greater secretion from the stromal vascular fraction than from adipocytes and with greater secretion from visceral than subcutaneous adipose tissue sites. This proinflammatory state is associated with insulin resistance and ameliorated by weight loss, with concurrent increase in production of the anti-inflammatory adipokine adiponectin. CONCLUSION: Although these associations between obesity and inflammation are clearly important, many questions remain unresolved. It is unclear if benefits of weight loss pertain only to those with a proinflammatory profile, who receive a particular type of obesity surgical procedure, or whether these benefits are sustained over a lifetime. The outcomes associated with anti-inflammatory nutrient supplementation, with or without weight loss, in the obese would also increase our understanding.

JPEN J Parenter Enteral Nutr. 2008 Nov-Dec;32(6):645-7

Patterns of abdominal fat distribution: the Framingham Heart Study.

OBJECTIVE: The prevalence of abdominal obesity exceeds that of general obesity. We sought to determine the prevalence of abdominal subcutaneous and visceral obesity and to characterize the different patterns of fat distribution in a community-based sample. RESEARCH DESIGN AND METHODS: Participants from the Framingham Heart Study (n = 3,348, 48% women, mean age 52 years) underwent multidetector computed tomography; subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) volumes were assessed. Sex-specific high SAT and VAT definitions were based on 90th percentile cut points from a healthy referent sample. Metabolic risk factors were examined in subgroups with elevated SAT and VAT. RESULTS: The prevalence of high SAT was 30% (women) and 31% (men) and that for high VAT was 44% (women) and 42% (men). Overall, 27.8% of the sample was discordant for high SAT and high VAT: 19.9% had SAT less than but VAT equal to or greater than the 90th percentile, and 7.9% had SAT greater than but VAT less than the 90th percentile. The prevalence of metabolic syndrome was higher among women and men with SAT less than the 90th percentile and high VAT than in those with high SAT but VAT less than the 90th percentile, despite lower BMI and waist circumference. Findings were similar for hypertension, elevated triglycerides, and low HDL cholesterol. CONCLUSIONS: Nearly one-third of our sample has abdominal subcutaneous obesity, and >40% have visceral obesity. Clinical measures of BMI and waist circumference may misclassify individuals in terms of VAT and metabolic risk.

Diabetes Care. 2009 Mar;32(3):481-5

The effect of training in reduced energy density eating and food self-monitoring accuracy on weight loss maintenance.

BACKGROUND: Failure to maintain weight losses in lifestyle change programs continues to be a major problem and warrants investigation of innovative approaches to weight control. OBJECTIVE: The goal of this study was to compare two novel group interventions, both aimed at improving weight loss maintenance, with a control group. METHODS AND PROCEDURES: A total of 103 women lost weight on a meal replacement-supplemented diet and were then randomized to one of three conditions for the 14-week maintenance phase: cognitive-behavioral treatment (CBT); CBT with an enhanced food monitoring accuracy (EFMA) program; or these two interventions plus a reduced energy density eating (REDE) program. Assessments were conducted periodically through an 18-month postintervention. Outcome measures included weight and self-reported dietary intake. Data were analyzed using completers only as well as baseline-carried-forward imputation. RESULTS: Participants lost an average of 7.6 +/- 2.6 kg during the weight loss phase and 1.8 +/- 2.3 kg during the maintenance phase. Results do not suggest that the EFMA intervention was successful in improving food monitoring accuracy. The REDE group decreased the energy density (ED) of their diets more so than the other two groups. However, neither the REDE nor the EFMA condition showed any advantage in weight loss maintenance. All groups regained weight between 6- and 18-month follow-ups. DISCUSSION: Although no incremental weight maintenance benefit was observed in the EFMA or EFMA + REDE groups, the improvement in the ED of the REDE group’s diet, if shown to be sustainable in future studies, could have weight maintenance benefits.

Obesity (Silver Spring). 2008 Sep;16(9):2016-23

Leptin resistance exacerbates diet-induced obesity and is associated with diminished maximal leptin signalling capacity in rats.

AIMS/HYPOTHESIS: Leptin resistance is generally considered a consequence of obesity. We postulated that leptin resistance is associated with diminished hypothalamic leptin signalling capacity and that leptin resistance is causal to obesity. We assessed maximal leptin-mediated binding of the transcription factor signal transducer and activator of transcription 3 (STAT3), and the response to high-fat feeding in lean leptin-resistant rats. MATERIALS AND METHODS: Recombinant adeno-associated virus encoding rat leptin cDNA (rAAV-leptin) or control vector were administered by intracerebroventricular injection to lean F344 x BN rats for up to 150 days, and food consumption, body weight, serum leptin and glucose tolerance were measured. Leptin-mediated hypothalamic transcription factor binding was assessed at day 150 following an intracerebroventricular injection of 2 mug leptin. Rats pretreated with either control or rAAV-leptin vector for 94 days were given a high-fat diet, and energy intake, body weight gain and adiposity were examined. RESULTS: The rAAV-leptin-treated rats initially responded to leptin gene delivery then became leptin-resistant. They displayed persistent submaximal hypothalamic leptin signalling and enhanced insulin sensitivity, yet maximal hypothalamic signalling capacity was decreased by more than 50%. On a high-fat diet, the leptin-resistant rats consumed more energy, gained more weight and accumulated greater visceral fat mass than controls. CONCLUSIONS/INTERPRETATION: The maximal hypothalamic leptin signalling capacity was diminished in leptin-resistant rats receiving central rAAV-leptin gene therapy. Moreover, this leptin-invoked leptin resistance perturbs the regulation of energy homeostasis in response to high fat exposure, producing augmented energy consumption. This, coupled with potential hypersensitivity to insulin, creates a milieu favouring fat deposition. Our data suggest that leptin resistance is both a consequence and cause of obesity.

Diabetologia. 2005 Jun;48(6):1075-83

Leptin resistance: a possible interface of inflammation and metabolism in obesity-related cardiovascular disease.

Leptin is an adipocyte-derived hormone and cytokine that regulates energy balance through a wide range of functions, including several that are important to cardiovascular health. Increased circulating leptin, a marker of leptin resistance, is common in obesity and independently associated with insulin resistance and cardiovascular disease (CVD) in humans. The mechanisms of leptin resistance include genetic mutation, leptin self-regulation, limited tissue access, and cellular or circulating molecular regulation. Evidence suggests that central leptin resistance causes obesity and that obesity-induced leptin resistance injures numerous peripheral tissues, including liver, pancreas, platelets, vasculature, and myocardium. This metabolic- and inflammatory-mediated injury may result from either resistance to leptin’s action in selective tissues, or excess leptin action from adiposity-associated hyperleptinemia. In this sense, the term “leptin resistance” encompasses a complex pathophysiological phenomenon. The leptin axis has functional interactions with elements of metabolism, such as insulin, and inflammation, including mediators of innate immunity, such as interleukin-6. Leptin is even purported to physically interact with C-reactive protein, resulting in leptin resistance, which is particularly intriguing, given C-reactive protein’s well-studied relationship to cardiovascular disease. Given that plasma levels of leptin and

inflammatory markers are correlated and also predict cardiovascular risk, it is conceivable that part of this risk may be mediated through leptin resistance-related insulin resistance, chronic inflammation, type II diabetes, hypertension, atherothrombosis, and myocardial injury. Leptin resistance and its interactions with metabolic and inflammatory factors, therefore, represent potential novel diagnostic and therapeutic targets in obesity-related cardiovascular disease.

J Am Coll Cardiol. 2008 Oct 7;52(15):1201-10

Leptin resistance: a prediposing factor for diet-induced obesity.

Obesity is a resilient and complex chronic disease. One potential causative factor in the obesity syndrome is leptin resistance. Leptin behaves as a potent anorexic and energy-enhancing hormone in most young or lean animals, but its effects are diminished or lacking in the obese state associated with a normal genetic background. Emerging evidence suggests that leptin resistance predisposes the animal to exacerbated diet-induced obesity (DIO). Elevation of central leptin in young, lean rats induces a leptin resistance that precludes obesity on a chow diet but accelerates high-fat (HF)-induced obesity. Similarly, chronic dietary fructose consumption evokes a leptin resistance that causes obesity only upon HF exposure. Inherent central leptin insensitivity also contributes to dietary weight gain in certain obesity-prone rats. Conversely, aged, leptin-resistant animals are obese with continuous chow feeding and demonstrate aggravated obesity when challenged with an HF diet. Additionally, a submaximal central blockade with a leptin antagonist leads to obesity on both chow and HF diets, as is the case in rodents with leptin receptor deficiency of genetic origin. Despite the differences in the incidence of obesity on a chow diet, all of these forms of leptin resistance predispose rodents to aggravated HF-mediated obesity. Moreover, once leptin resistance takes hold, it aggravates DIO, and the leptin resistance and obesity compound one another, promoting a vicious cycle of escalating weight gain.

Am J Physiol Regul Integr Comp Physiol. 2009 Mar;296(3):R493-500

Evaluation of the effects of caffeine in the microcirculation and edema on thighs and buttocks using the orthogonal polarization spectral imaging and clinical parameters.

Gynoid lipodystrophy, also known as cellulite, is a common multifactorial entity that affects millions of women around the world. There have been few scientific articles dealing with its physiology and treatment in the past few years, and vascular changes seem to play an important role in its pathophysiology. Skin microvascular alterations can be observed noninvasively with a new method called orthogonal polarization spectral imaging, which was used to evaluate the effectiveness of an anticellulite drug composed mainly of a 7% caffeine solution. Microcirculatory parameters evaluated were functional capillary density (FCD; number of flowing capillaries per unit area), diameter of the dermic papilla (DPD), and capillary diameter (CD). The clinical parameters analyzed were centimetrical measurements of thighs and hips and the influence of tobacco, alcohol, and physical activities on the efficacy of the treatment. After 1 month of treatment, statistical application of chi-squared and Z approximation tests showed, in treated patients, statistically significant reduction of thigh circumferences in more than 80% of the cases and reduction of hip circumference in 67.7%. FCD, DPD, and CD did not change significantly after treatment. Smoking as well as alcohol consumption and regular physical activity were not significantly related to the centimetrical reduction observed in treated thighs and hips.

J Cosmet Dermatol. 2007 Jun;6(2):102-7

Ascorbate is consumed stoichiometrically in the uncoupled reactions catalyzed by prolyl 4-hydroxylase and lysyl hydroxylase.

The hydroxylation of proline and lysine residues by the collagen hydroxylases is coupled with a stoichiometric decarboxylation of 2-oxoglutarate. Ascorbate is virtually a specific requirement for these enzymes, but previous studies have demonstrated that it is not consumed during most catalytic cycles. Prolyl 4-hydroxylase and lysyl hydroxylase are known also to catalyze an uncoupled decarboxylation of 2-oxoglutarate in the absence of the peptide substrate. It is shown here that, unlike the complete hydroxylation reaction, the uncoupled decarboxylation reaction involves stoichiometric ascorbate consumption. This stoichiometric ascorbate consumption was also seen when the rate of the uncoupled prolyl 4-hydroxylase reaction was enhanced by the addition of poly(L-proline). Since collagen hydroxylases may catalyze occasional uncoupled reaction cycles even in the presence of the peptide substrates, the main function of ascorbate in these reactions in vivo is suggested to be that of reactivating the enzymes after such uncoupled cycles.

J Biol Chem. 1984 May 10;259(9):5403-5

Use of topical ascorbic acid and its effects on photodamaged skin topography.

OBJECTIVE: To determine the efficacy of topical ascorbic acid application in treating mild to moderate photodamage of facial skin using an objective, computer-assisted image analysis of skin surface topography and subjective clinical, photographic, and patient self-appraisal questionnaires. DESIGN: A 3-month, randomized, double-blind, vehicle-controlled study. SETTING: Facial plastic surgery private practice. PATIENTS: Nineteen evaluable volunteer sample patients aged between 36 and 72 years with Fitzpatrick skin types I, II, and III who were in good physical and mental health with mild to moderately photodamaged facial skin were considered for analysis. INTERVENTION: Coded, unmarked medications were randomly assigned to the left and right sides of each subject’s face, one containing the active agent, topical ascorbic acid (Cellex-C high-potency serum; Cellex-C International, Toronto, Ontario), the other, the vehicle serum (Cellex-C International). Three drops (0.5 mL) of each formulation were applied daily to the randomly assigned hemifaces over the 3-month study period. Treatment assignments were not disclosed to subjects, clinicians, or personnel involved in analyzing skin replicas. MAIN OUTCOME MEASURES: Specific clinical parameters were evaluated and graded on a 0- to 9-point scale (0, none; 1-3, mild; 4-6, moderate; and 7-9, severe). Reference photographs were used to standardize grading criteria. Overall investigator scores were compared with baseline and graded as excellent (much improved), good (improved), fair (slightly improved), no change, or worse. Patient self-appraisal questionnaires rated the degree of improvement (much improved, improved, slightly improved, no change, or worse) and reported adverse effects (burning, stinging, redness, peeling, dryness, discoloration, itching, and rash). Standard photographs were taken at baseline, including anteroposterior and left and right oblique views to facilitate subsequent clinical evaluations, and at the end of therapy for comparison. Optical profilometry analysis was performed on the skin surface replicas of the lateral canthal (crow’s feet) region, comparing baseline to end-of-study specimens. Using this computer-based system, the resulting image was digitally analyzed, and numeric values were assigned to reflect surface features. The parameters obtained included Rz, Ra, and shadows. These values provided objective data that document pretreatment and posttreatment texture changes proportional to the degree of wrinkling, roughness, and other surface irregularities. RESULTS: Optical profilometry image analysis demonstrated a statistically significant 73.7% improvement in the Ra and shadows north-south facial axis values with active treatment greater than vehicle control, as well as a trend for improvement in the Rz north-south facial axis parameter, showing a 68.4% greater improvement of active treatment vs vehicle control. Clinical assessment demonstrated significant improvement with active treatment greater than control for fine wrinkling, tactile roughness, coarse rhytids, skin laxity/tone, sallowness/yellowing, and overall features. Patient questionnaire results demonstrated statistically significant improvement overall, active treatment 84.2% greater than control. Photographic assessment demonstrated significant improvement, active treatment 57.9% greater than control. CONCLUSIONS: A 3-month daily regimen of topical ascorbic acid provided objective and subjective improvement in photodamaged facial skin. Skin replica optical profilometry is an objective method for quantification of the skin surface texture changes.

Arch Otolaryngol Head Neck Surg. 1999 Oct;125(10):1091-8

Topical ascorbic acid on photoaged skin. Clinical, topographical and ultrastructural evaluation: double-blind study vs. placebo.

Vitamin C is known for its antioxidant potential and activity in the collagen biosynthetic pathway. Photoprotective properties of topically applied vitamin C have also been demonstrated, placing this molecule as a potential candidate for use in the prevention and treatment of skin ageing. A topically applied cream containing 5% vitamin C and its excipient were tested on healthy female volunteers presenting with photoaged skin on their low-neck and arms in view to evaluate efficacy and safety of such treatment. A double-blind, randomized trial was performed over a 6-month period, comparing the action of the vitamin C cream vs. excipient on photoaged skin. Clinical assessments included evaluation at the beginning and after 3 and 6 months of daily treatment. They were performed by the investigator and compared with the volunteer self assessment. Skin relief parameters were determined on silicone rubber replicas performed at the same time-points. Cutaneous biopsies were obtained at the end of the trial and investigated using immunohistochemistry and electron microscopy. Clinical examination by a dermatologist as well as self-assessment by the volunteers disclosed a significant improvement, in terms of the ‘global score’, on the vitamin C-treated side compared with the control. A highly significant increase in the density of skin microrelief and a decrease of the deep furrows were demonstrated. Ultrastructural evidence of the elastic tissue repair was also obtained and well corroborated the favorable results of the clinical and skin surface examinations. Topical application of 5% vitamin C cream was an effective and well-tolerated treatment. It led to a clinically apparent improvement of the photodamaged skin and induced modifications of skin relief and ultrastructure, suggesting a positive influence of topical vitamin C on parameters characteristic for sun-induced skin ageing.

Exp Dermatol. 2003 Jun;12(3):237-44

Double-blind, half-face study comparing topical vitamin C and vehicle for rejuvenation of photodamage.

BACKGROUND: Aging of the population, in particular the “baby boomers,” has resulted in increased interest in methods of reversal of photodamage. Non-invasive treatments are in high demand, and our knowledge of mechanisms of photodamage to skin, protection of the skin, and repair of photodamage are becoming more sophisticated and complex. OBJECTIVE: The objective of this study is to determine if the topical use of a vitamin C preparation can stimulate the skin to repair photodamage and result in clinically visible differences, as well as microscopically visible improvement. METHODS: Ten patients applied in a double-blind manner a newly formulated vitamin C complex having 10% ascorbic acid (water soluble) and 7% tetrahexyldecyl ascorbate (lipid soluble) in an anhydrous polysilicone gel base to one-half of the face and the inactive polysilicone gel base to the opposite side. Clincial evaluation of wrinkling, pigmentation, inflammation, and hydration was performed prior to the study and at weeks 4, 8, and 12. Two mm punch biopsies of the lateral cheeks were performed at 12 weeks in four patients and stained with hematoxylin and eosin, as well as in situ hybridization studies using an anti-sense probe for mRNA for type I collagen. A questionnaire was also completed by each patient. RESULTS: A statistically significant improvement of the vitamin C-treated side was seen in the decreased photoaging scores of the cheeks (P = 0.006) and the peri-oral area (P = 0.01). The peri-orbital area improved bilaterally, probably indicating improved hydration. The overall facial improvement of the vitamin C side was statistically significant (P = 0.01). Biopsies showed increased Grenz zone collagen, as well as increased staining for mRNA for type I collagen. No patients were found to have any evidence of inflammation. Hydration was improved bilaterally. Four patients felt that the vitamin C-treated side improved unilaterally. No patient felt the placebo side showed unilateral improvement. CONCLUSION: This formulation of vitamin C results in clinically visible and statistically significant improvement in wrinkling when used topically for 12 weeks. This clinical improvement correlates with biopsy evidence of new collagen formation.

Dermatol Surg. 2002 Mar;28(3):231-6

Topical vitamin C: a useful agent for treating photoaging and other dermatologic conditions.

BACKGROUND: Cosmeceuticals containing antioxidants are among the most popular antiaging remedies. Topically applied antioxidants exert their benefits by offering protection from damaging free radicals produced when skin is exposed to ultraviolet light or allowed to age naturally. Vitamin C is a naturally occurring potent water-soluble antioxidant. Accordingly, it has been incorporated into a variety of cosmeceuticals designed to protect and rejuvenate photoaged skin. OBJECTIVE: This article reviews the scientific data and clinical studies supporting the use of topically applied vitamin C for treating photoaged skin. Other innovative uses for vitamin C cosmeceuticals are also discussed. CONCLUSION: A significant body of scientific research supports the use of cosmeceuticals containing vitamin C. Cutaneous benefits include promoting collagen synthesis, photoprotection from ultraviolet A and B, lightening hyperpigmentation, and improvement of a variety of inflammatory dermatoses. Because of the diverse biologic effects of this compound, topical vitamin C has become a useful part of the dermatologist’s armamentarium.

Dermatol Surg. 2005 Jul;31(7 Pt 2):814-7; discussion 818

Aging- and photoaging-dependent changes of enzymic and nonenzymic antioxidants in the epidermis and dermis of human skin in vivo.

This is a comprehensive study of the changes in major antioxidant enzymes and antioxidant molecules during intrinsic aging and photoaging processes in the epidermis and dermis of human skin in vivo. We show that the activities of superoxide dismutase and glutathione peroxidase are not changed during these processes in human skin in vivo. Interestingly, the activity of catalase was significantly increased in the epidermis of photoaged (163%) and naturally aged (118%) skin (n = 9), but it was significantly lower in the dermis of photoaged (67% of the young skin level) and naturally aged (55%) skin compared with young (n = 7) skin. The activity of glutathione reductase was significantly higher (121%) in naturally aged epidermis. The concentration of alpha-tocopherol was significantly lower in the epidermis of photoaged (56% of young skin level) and aged (61%) skin, but this was not found to be the case in the dermis. Ascorbic acid levels were lower in both epidermis (69% and 61%) and dermis (63% and 70%) of photoaged and naturally aged skin, respectively. Gluta thione concentrations were also lower. Uric acid did not show any significant changes. Our results suggest that the components of the antioxidant defense system in human skin are probably regulated in a complex manner during the intrinsic aging and photoaging processes.

J Invest Dermatol. 2001 Nov;117(5):1212-7

Dermal connective tissue metabolism in photoageing.

The term photoageing describes the clinical and histological cutaneous changes that are the consequence of repeated chronic sun exposures and are qualitatively different from those observed in chronological ageing. The connective tissue of the skin is composed mainly of collagen, glycosaminoglycans and elastin and, thus, alterations of these components in photoageing are briefly reviewed in the present article. Collagen changes in photoageing are partly explained by cross-links as well as the unbalanced regulation of collagen production and breakdown. Some visible skin changes can be induced by the consequence of dermal glycosaminoglycans, because the total amount, as well as the composition of the main disaccharide units, is significantly altered in the exposed sites of both aged people and photoaged mice. As for the mechanism of solar elastosis, increased elastin mRNA levels resulting from transcriptional up-regulation of the gene have been reported. Taken together, all components of the dermal connective tissue are affected by chronic actinic damage; however, further in vitro investigation is required to unmask the exact events in photoageing. With regard to this, our novel three-dimensional culture system should be of great help because it mimics the in vivo condition by self producing the extracellular matrices.

Australas J Dermatol. 1998 Feb;39(1):19-23

Skin aging 2003: recent advances and current concepts.

In developed countries, interest in cutaneous aging is in large part the result of a progressive, dramatic rise over the past century in the absolute number and proportion of the population who are elderly. The psychosocial, as well as physiologic, effects of skin aging on older persons have created a demand for a better understanding of the aging process and particularly for effective interventions. Skin aging is a complex process determined by the genetic endowment of the individual and by environmental factors. The appearance of old skin and the clinical consequences of skin aging have been well-known for centuries, but it is only in the past 50 years that mechanisms and mediators have been pursued systematically. Still, within a relatively short time, there has been tremendous progress, a progress greatly enhanced by basic gerontologic research using immunologic, biochemical, and in particular, molecular biologic approaches.

Cutis. 2003 Sep;72(3 Suppl):5-10; discussion 10

Regulation of collagen synthesis in human dermal fibroblasts by the sodium and magnesium salts of ascorbyl-2-phosphate.

Ascorbic acid has been shown to stimulate collagen synthesis in dermal fibroblasts by increasing the rate of transcription of collagen genes. Experiments involving the use of ascorbic acid require daily supplementation due to the instability of the molecule in aqueous solutions. In order to provide a more stable alternative to ascorbic acid, two salts of ascorbyl-2-phosphate, having a greater chemical stability than ascorbic acid, were tested for their ability to stimulate collagen synthesis in monolayer fibroblast cultures. The concentration and time dependence of their activities were compared with ascorbic acid. The magnesium salt of ascorbyl-2-phosphate was found to be equivalent to ascorbic acid in stimulating collagen synthesis in these assays, while the sodium salt required at least a tenfold greater concentration to produce the same effect as ascorbic acid. Solutions of either ascorbic acid or the ascorbyl-2-phosphate analogs (at 10 mM) in phosphate-buffered saline (PBS) were relatively stable as shown by their decay rates and their ability to stimulate collagen synthesis even after nine days in solution prior to testing their effects on cultured cells. Ascorbic acid was unstable at neutral pH compared to solutions of either sodium or magnesium ascorbyl-2-phosphate. These data support the use of magnesium ascorbyl-2-phosphate in experiments where stability of ascorbic acid is a concern, e.g. in long-term cultures or in in vivo studies.

Skin Pharmacol. 1993;6(1):65-71

L-ascorbic acid 2-phosphate stimulates collagen accumulation, cell proliferation, and formation of a three-dimensional tissuelike substance by skin fibroblasts.

Proliferation of human skin fibroblasts was stimulated significantly by the presence of L-ascorbic acid 2-phosphate (Asc 2-P). The presence of Asc 2-P (0.1-1.0 mM) in the culture medium for 3 weeks enhanced the relative rate of collagen synthesis to total protein synthesis 2-fold as well as cell growth 4-fold. Coexistence of L-azetidine 2-carboxylic acid (AzC), an inhibitor of collagen synthesis, attenuated both effects of Asc 2-P in a dose-

dependent manner. Supplemen-tation of the medium with Asc 2-P also accelerated procollagen processing to collagen and deposition of collagen in the cell layer. Among the acidic glycosaminoglycans (GAG), another major component of extracellular matrix (ECM), deposition of sulfated forms was increased by the additive. Electron microscopic observations showed multilayered, rough endoplasmic reticulum-rich cells surrounded by dense ECM. These results indicate that Asc 2-P is useful in culture systems as a long-acting vitamin C derivative and also that it promotes reorganization of a three-dimensional tissuelike substance from skin fibroblasts in culture by stimulating collagen accumulation in the fibroblasts.

J Cell Physiol. 1989 Jan;138(1):8-16

Epidermal growth factor inhibits transcription of type I collagen genes and production of type I collagen in cultured human skin fibroblasts in the presence and absence of L-ascorbic acid 2-phosphate, a long-acting vitamin C derivative.

Recombinant human epidermal growth factor (EGF, 2-10 ng/ml) stimulated growth and production of non-collagenous proteins, but inhibited production of collagen by 60% in cultured human skin fibroblasts. Type analysis of the collagen produced indicated that inhibition of the collagen production observed was mainly a reflection of a reduction in type I collagen. The accumulation of pro alpha 1(I) and pro alpha 2(I) mRNAs and the transcriptional activity of these genes were determined in human skin fibroblasts in order to investigate site(s) of regulation of type I collagen production by human EGF in the absence and presence of L-ascorbic acid 2-phosphate (Asc 2-P), a long-acting vitamin C derivative. Human EGF (10 ng/ml) used alone reduced the steady state levels of mRNAs for pro alpha 1(I) and pro alpha 2(I) chains and transcriptional activity of these genes in vitro by 45%. Asc 2-P (0.2 mM) alone, on the other hand, raised production of type I collagen and the steady state levels of mRNAs for pro alpha 1(I) and pro alpha 2(I) collagen chains as well as stimulated transcriptional activity of these genes. Human EGF attenuated these stimulative effects of Asc 2-P. These results indicate that human EGF regulates type I collagen synthesis at the transcriptional level in cultured fibroblasts in the presence and absence of Asc 2-P. The possibility that human EGF plays a role as a regulator of type I collagen genes in vivo was discussed.

J Biol Chem. 1991 May 25;266(15):9997-10003

Ascorbic acid preferentially enhances type I and III collagen gene transcription in human skin fibroblasts.

Ascorbic acid is a potent stimulator for type I and III collagen expression in human skin fibroblasts; stimulation of type I and III collagen synthesis and their mRNA levels by ascorbic acid has been reported previously. Nuclear run-on experiments demonstrated that ascorbic acid enhanced the transcription of type I and III collagen genes 4- and 3.4-fold respectively, whereas transcription of type IV collagen was slightly stimulated (1.7-fold). The results suggest that ascorbic acid preferentially enhanced type I and III collagen transcription.

J Dermatol Sci. 1996 Mar;11(3):250-3

Topically applied vitamin C enhances the mRNA level of collagens I and III, their processing enzymes and tissue inhibitor of matrix metalloproteinase 1 in the human dermis.

Ascorbic acid (vitamin C) is a cofactor required for the function of several hydroxylases and monooxygenases. It is not synthesized in humans and some other animal species and has to be provided by diet or pharmacologic means. Its absence is responsible for scurvy, a condition related in its initial phases to a defective synthesis of collagen by the reduced function of prolylhydroxylase and production of collagen polypeptides lacking hydroxyproline, therefore, they are unable to assemble into stable triple-helical collagen molecules. In fibroblast cultures, vitamin C also stimulates collagen production by increasing the steady-state level of mRNA of collagen types I and III through enhanced transcription and prolonged half-life of the transcripts. The aim of the experimental work has been to evaluate the effect on dermal cells of a preparation of vitamin C topically applied on one side vs placebo on the other side of the dorsal face of the upper forearm of postmenopausal women. Biopsies were collected on both sides and the level of mRNA measured by non competitive reverse transcription-polymerase chain reaction made quantitative by the simultaneous transcription and amplification of synthetic RNA used as internal standards. The mRNA of collagen type I and type III were increased to a similar extent by vitamin C and that of three post-translational enzymes, the carboxy- and amino-procollagen proteinases and lysyloxidase similarly increased. The mRNA of decorin was also stimulated, but elastin, and fibrillin 1 and 2 were not modified by the vitamin. The expression of matrix metalloproteinases 1, 2, and 9 was not significantly changed, but an increased level of tissue inhibitor of matrix metalloproteinase 1 mRNA was observed without modification of tissue inhibitor of matrix metalloproteinase 2 mRNA. The stimulating activity of topical vitamin C was most conspicuous in the women with the lowest dietary intake of the vitamin and unrelated to the level of actinic damage. The results indicate that the functional activity of the dermal cells is not maximal in postmenopausal women and can be increased.

J Invest Dermatol. 2001 Jun;116(6):853-9

Topically applied vitamin C increases the density of dermal papillae in aged human skin.

BACKGROUND: The influence of ageing on the density of the functional entities of the papillae containing nutritive capillaries, here in terms as the papillary index, and the effect of topically applied vitamin C were investigated by

confocal laser scanning microscopy (CLSM) in vivo. METHODS: The age dependency of the papillary index was determined by CLSM on 3 different age groups. Additionally, we determined the effect of a topical cream containing 3% vitamin C against the vehicle alone using daily applications for four months on the volar forearm of 33 women. RESULTS: There were significant decreases in the papillary index showing a clear dependency on age. Topical vitamin C resulted in a significant increase of the density of dermal papillae from 4 weeks onward compared to its vehicle. Reproducibility was determined in repeated studies. CONCLUSIONS: Vitamin C has the potential to enhance the density of dermal papillae, perhaps through the mechanism of angiogenesis. Topical vitamin C may have therapeutical effects for partial corrections of the regressive structural changes associated with the aging process.

BMC Dermatol. 2004 Sep 29;4(1):13

Enzymic and non-enzymic antioxidants in epidermis and dermis of human skin.

We measured enzymic and non-enzymic antioxidants in human epidermis and dermis from six healthy volunteers undergoing surgical procedures. Epidermis was separated from dermis by curettage and antioxidants were measured by high-performance liquid chromatography (HPLC) or standard spectrophotometric methods. The concentration of every antioxidant (referenced to skin wet weight) was higher in the epidermis than in the dermis. Among the enzymic antioxidants, the activities of superoxide dismutase, glutathione peroxidase, and glutathione reductase were higher in the epidermis compared to the dermis by 126, 61, and 215%, respectively. Catalase activity in particular was much higher (720%) in the epidermis. Glucose-6-phosphate dehydrogenase and isocitrate dehydrogenase, which provide reduced nicotinamide adenine dinucleotide phosphate (NADPH), also showed higher activity in the epidermis than the dermis by 111% and 313%, respectively. Among the lipophilic antioxidants, the concentration of alpha-tocopherol was higher in the epidermis than the dermis by 90%. The concentration of ubiquinol 10 was especially higher in the epidermis, by 900%. Among the hydrophilic antioxidants, concentrations of ascorbic acid and uric acid were also higher in the epidermis than in the dermis by 425 and 488%, respectively. Reduced glutathione and total glutathione were higher in the epidermis than in the dermis by 513 and 471%. Thus the antioxidant capacity of the human epidermis is far greater than that of dermis. As the epidermis composes the outermost 10% of the skin and acts as the initial barrier to oxidant assault, it is perhaps not surprising that it has higher levels of antioxidants.

J Invest Dermatol. 1994 Jan;102(1):122-4