Efficacy of antioxidant treatment in reducing resistin serum levels: a randomized study

Ameliorating impact of coenzyme Q10 on the profile of adipokines, cardiomyopathy, and hematological markers correlated with the glucotoxicity sequelae in diabetic rats

BACKGROUND

In diabetes, high blood glucose induces glucotoxicity, resulting in the further damage of pancreatic beta-cells and then precipitating diabetic complications. This study was aimed to investigate the relationship between glucotoxicity with the level of adipokines, diabetic cardiomyopathy, and hematological markers. Moreover, the study examined the potential modulatory effect of coenzyme Q10 (CoQ10) on the aforementioned markers associated with the sequelae of diabetes mellitus.

MATERIAL AND METHODS

Twenty-four male rats were randomly assigned to receive an injection of STZ to induce diabetes (n = 16) or to remain uninduced (n = 8). The hyperglycemic status was induced in fasting rats by single intraperitoneal injection of STZ (45 mg /kg b.w.) dissolved in citrate buffer (pH 4.5). Three days after STZ injection, rats were divided into three groups; Normal control group (A), Diabetic control group (B), and CoQ10- treated diabetic group (C). The group (C) was fed with the basal diet supplemented with 5 g of CoQ10 per kilogram of diet for three weeks after the diabetes induction. After 21 days, the blood and serum samples were taken to conduct biochemical analyses. Blood glucose was determined by Blood Glucose Monitoring System. Adipokines or cytokines were evaluated by ELISA from a serum sample. Cardiac myopathy biomarkers were estimated by UP-Converting Phosphor Immunoassay Analyzer, and hematological parameters were measured by automatic hematology analyzer.

RESULTS

In hyperglycemic rats, the level of fasting blood glucose, and serum level of resistin, omentin, TNF-α, and cardiomyopathy biomarkers significantly increased (P < 0.05). The treatment with CoQ10 significantly decreased the profile of adipokines and cardiomyopathy markers (cardiac enzymes and LPPLA2) in diabetic rats and also reduced glucose levels (P < 0.05). Lymphocyte percentages significantly decreased while significant increases were observed in granulocytes and MID percentages in hyperglycemic rats.

CONCLUSION

Diabetic rats had higher serum levels of adipokines and cardiomyopathy markers. Among the hematological markers, GRA% and MID% increased while LYM% decreased. The profile of adipokines and cardiomyopathy markers improved when CoQ10 was supplemented. The study suggests that CoQ10 may have a beneficial effect on improving diabetic complications.

Effects of PCSK9 Targeting: Alleviating Oxidation, Inflammation, and Atherosclerosis

Characterized as a chronic inflammatory disease of the large arteries, atherosclerosis is the primary cause of cardiovascular disease, the leading contributor of morbidity and mortality worldwide. Elevated plasma cholesterol levels and chronic inflammation within the arterial plaque are major mediators of plaque initiation, progression, and instability. In 2003, the protein PCSK9 (proprotein convertase subtilisin/kexin 9) was discovered to play a critical role in cholesterol regulation, thus becoming a key player in the mechanisms behind atherosclerotic plaque development. Emerging evidence suggests that PCSK9 could potentially have effects on atherosclerosis that are independent of cholesterol levels. The objective of this review was to discuss the role on PCSK9 in oxidation, inflammation, and atherosclerosis. This function activates proinflammatory cytokine production and affects oxidative modifications within atherosclerotic lesions, revealing its more significant role in atherosclerosis. Although a variety of evidence demonstrates that PCSK9 plays a role in atherosclerotic inflammation, the direct mechanism of involvement is still unknown, driving a gap in knowledge to such a predominant player in cardiovascular disease. Investigation of proteins structurally related to PCSK9 may interestingly be the link in unveiling the mechanistic role of this protein’s involvement in oxidation and inflammation. Importantly, the unique structure of PCSK9 bears structural homology to a one‐of‐a‐kind domain found in the metabolic protein resistin, which is responsible for many of the same inflammatory outcomes as PCSK9. Closing this gap in knowledge of PCSK9`s role in atherosclerotic oxidation and inflammation will provide fundamental information for understanding, preventing, and treating cardiovascular disease.

Effects of vitamin C supplementation on glycaemic control: a systematic review and meta-analysis of randomised controlled trials

Randomised controlled trials (RCTs) have observed contrasting results on the effects of vitamin C on circulating biomarkers of glycaemic and insulin regulation. We conducted a systematic review and meta-analysis of RCTs testing the effect of vitamin C administration on glucose, HbA1c and insulin concentrations. Four databases (PubMed, Embase, Scopus and Cochrane Library) were used to retrieve RCTs published from inception until April 2016 and testing the effects of vitamin C in adult participants. The screening of 2008 articles yielded 22 eligible studies (937 participants). Overall, vitamin C did not modify glucose, HbA1c and insulin concentrations. However, subgroup analyses showed that vitamin C significantly reduced glucose concentrations (-0.44 mmol/l, 95% CI: -0.81, -0.07, P=0.01) in patients with type 2 diabetes and in interventions with a duration greater than 30 days (-0.53%, 95% CI: -0.79, -0.10, P=0.02). Vitamin C administration had greater effects on fasting (-13.63 pmol/l, 95% CI: -22.73, -4.54, P<0.01) compared to postprandial insulin concentration. Meta-regression analyses showed that age was a modifier of the effect of vitamin C on insulin concentration. Furthermore, the effect size was associated with baseline BMI and plasma glucose levels, and with the duration of the intervention. In conclusion, greater reduction in glucose concentrations observed in patients with diabetes, older individuals and with more prolonged supplementation. Personalised interventions with vitamin C may represent a feasible future strategy to enhance benefits and efficacy of interventions. Nevertheless, results need to be interpreted cautiously due to limitations in the primary studies analysed.

Vitamin C modulates the metabolic and cytokine profiles, alleviates hepatic endoplasmic reticulum stress, and increases the life span of Gulo-/- mice

Suboptimal intake of dietary vitamin C (ascorbate) increases the risk of several chronic diseases but the exact metabolic pathways affected are still unknown. In this study, we examined the metabolic profile of mice lacking the enzyme gulonolactone oxidase (Gulo) required for the biosynthesis of ascorbate. Gulo^−/− mice were supplemented with 0%, 0.01%, and 0.4% ascorbate (w/v) in drinking water and serum was collected for metabolite measurements by targeted mass spectrometry. We also quantified 42 serum cytokines and examined the levels of different stress markers in liver. The metabolic profiles of Gulo^−/− mice treated with ascorbate were different from untreated Gulo^−/− and normal wild type mice. The cytokine profiles of Gulo^−/− mice, in return, overlapped the profile of wild type animals upon 0.01% or 0.4% vitamin C supplementation. The life span of Gulo^−/− mice increased with the amount of ascorbate in drinking water. It also correlated significantly with the ratios of serum arginine/lysine, tyrosine/phenylalanine, and the ratio of specific species of saturated/unsaturated phosphatidylcholines. Finally, levels of hepatic phosphorylated endoplasmic reticulum associated stress markers IRE1α and eIF2α correlated inversely with serum ascorbate and life span suggesting that vitamin C modulates endoplasmic reticulum stress response and longevity in Gulo^−/− mice.

The acute impact of the intake of four types of bread on satiety and blood concentrations of glucose, insulin, free fatty acids, triglyceride and acylated ghrelin. A randomized controlled cross-over trial

The purpose of the present study is to compare the effects of four different breads (one commercial par-baked wheat bread, three sourdough breads prepared with commercial wheat flour, organic wheat flour, organic einkorn flour) in 16 healthy subjects. The primary outcome of this randomized cross-over trial was evaluating intra-individual changes in glycemic areas-under-the-curve (AUCs) after 50g carbohydrate portions of each bread; secondary outcomes were changes in insulin, fatty free acids (FFA), triglyceride, acylated ghrelin and satiety AUCs. Blood samples and satiety ratings were collected every 30-min for 2-h after the consumption of each bread. The einkorn flour showed the lowest amylase activity, the commercial flour the highest; commercial bread had the highest carbohydrate content and the lowest dietary fiber content. Glucose AUCs were significantly lower after the consumption of sourdough breads made with organic (12,754±1433mg/dL×h) and einkorn flour (12,216±1210mg/dL×h), with respect to the commercial bread (13,849±2193mg/dL×h). Insulin AUCs decreased after the consumption of all sourdough breads when compared to commercial bread. FFA and triglyceride AUCs did not differ by kind of breads. Median ghrelin AUC was significantly lower and satiety higher after the einkorn bread (3710pg/mL×h; 3225±2414, respectively) than after commercial bread consumption (4140pg/mL×h; 1706±1766, respectively), but not with other sourdough breads. In conclusion, the use of sourdough may improve the nutritional features of breads; einkorn bread induced the least disturbance in carbohydrate homeostasis and the greater satiety. If confirmed by further research, these results might have implications in the approach towards chronic dysmetabolic diseases.

Systematic review and meta-analysis of randomised controlled trials testing the effects of vitamin C supplementation on blood lipids

BACKGROUND & AIMS

Randomised controlled trials (RCTs) in humans revealed contradictory results regarding the effect of vitamin C supplementation on blood lipids. We aimed to conduct a systematic review and meta-analysis of RCTs investigating the effect of vitamin C supplementation on total cholesterol, low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C) and triglycerides and to determine whether the effects are modified by the participants' or intervention characteristics.

METHODS

Four databases (PubMed, Embase, Scopus and Cochrane Library) were searched from inception until August 2014 for RCTs supplementing adult participants with vitamin C for ≥ 2 weeks and reporting changes in blood lipids.

RESULTS

Overall, vitamin C supplementation did not change blood lipids concentration significantly. However, supplementation reduced total cholesterol in younger participants (≤52 years age) (-0.26 mmol/L, 95% CI: -0.45, -0.07) and LDL-C in healthy participants (-0.32 mmol/L, 95% CI: -0.57, -0.07). In diabetics, vitamin C supplementation reduced triglycerides significantly (-0.15 mmol/L, 95% CI: -0.30, -0.002) and increased HDL-C significantly (0.06 mmol/L, 95% CI: 0.02, 0.11). Meta-regression analyses showed the changes in total cholesterol (β: -0.24, CI: -0.36, -0.11) and in triglycerides (β: -0.17, CI: -0.30, -0.05) following vitamin C supplementation were greater in those with higher concentrations of these lipids at baseline. Greater increase in HDL-C was observed in participants with lower baseline plasma concentrations of vitamin C (β: -0.002, CI: -0.003, -0.0001).

CONCLUSIONS

Overall, vitamin C supplementation had no significant effect on lipid profile. However, subgroup and sensitivity analyses showed significant reductions in blood lipids following supplementation in sub-populations with dyslipidaemia or low vitamin C status at baseline. PROSPERO Database registration: CRD42014013487, http://www.crd.york.ac.uk/prospero/.

Impact of snacking pattern on overweight and obesity risk in a cohort of 11- to 13-year-old adolescents

OBJECTIVES

The association between snacking habits and overweight in adolescents is unclear. We evaluated the relation between snacking patterns and overweight/obesity in a cohort of 11- to 13-year-old Italian adolescents.

METHODS

The dietary habits of 400 randomly selected adolescents were evaluated; those with body mass index ≥ 85 th percentile were considered as overweight/obese. Participants were classified based on the percentage of caloric intake from snacks (<15%, 15%-20%, >20%), snacking frequency (1, 2, ≥ 3), and timing of consuming the most caloric snack (morning, afternoon, evening).

RESULTS

A minority of participants (13/400, 3.3%) did not consume any snacks; 5/13 (38.5) of them were overweight/obese. Among snackers (387/400), overweight/obesity prevalence was 10.4%, 14.4%, 20.5%, respectively, in those consuming <15%, 15% to 10%, and >20% of their energy intake from snacks. In a Poisson regression model, the overweight/obesity relative risks (RRs) were 1.35 (95% confidence interval [CI] 0.58-3.15) and 2.32 (1.10-4.89) for 15% to 20% and >20% calories/day from snacks, respectively. Overweight/obesity prevalence (from 9.6% to 22.6%) was correlated with snacking frequency (RR 2.20, 95% CI 0.92-5.27, and RR 4.17, 95% CI 1.60-10.9, for 2 and ≥ 3 snacks per day, respectively). The most caloric snacks were consumed in the morning (180/387) and afternoon (179/387); 28.6% of the predominantly evening snackers (28/387) were overweight/obese (RR 3.12, 95% CI 1.17-8.34).

CONCLUSIONS

Increased snacking calories, frequency, and evening snacking are independently associated with overweight/obesity in Italian middle-school adolescents.

Consuming more of daily caloric intake at dinner predisposes to obesity. A 6-year population-based prospective cohort study

BACKGROUND/OBJECTIVES

It has been hypothesized that assuming most of the caloric intake later in the day leads to metabolic disadvantages, but few studies are available on this topic. Aim of our study was to prospectively examine whether eating more of the daily caloric intake at dinner leads to an increased risk of obesity, hyperglycemia, metabolic syndrome, and non-alcoholic fatty liver disease (NAFLD).

SUBJECTS/METHODS

1245 non-obese, non-diabetic middle-aged adults from a population-based cohort underwent a 3-day food record questionnaire at enrollment. Anthropometric values, blood pressure, blood metabolic variables, and estimated liver fat were measured at baseline and at 6-year follow-up.

DESIGN

Prospective cohort study.

RESULTS

Subjects were divided according to tertiles of percent daily caloric intake at dinner. A significant increase in the incidence rate of obesity (from 4.7 to 11.4%), metabolic syndrome (from 11.1 to 16.1%), and estimated NAFLD (from 16.5 to 23.8%) was observed from the lower to higher tertile. In a multiple logistic regression model adjusted for multiple covariates, subjects in the highest tertile showed an increased risk of developing obesity (OR = 2.33; 95% CI 1.17-4.65; p = 0.02), metabolic syndrome (OR = 1.52; 95% CI 1.01-2.30; p = 0.04), and NAFLD (OR = 1.56; 95% CI 1.10-2.22; p = 0.01).

CONCLUSIONS

Consuming more of the daily energy intake at dinner is associated with an increased risk of obesity, metabolic syndrome, and NAFLD.

Immunological mechanisms in the pathophysiology of non-alcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH) is characterized by the presence of steatosis, inflammation and hepatocyte injury and constitutes hepatic manifestation of the metabolic syndrome. The pathogenesis of NASH is complex and implicates cross-talk between different metabolically active sites, such as liver and adipose tissue. Obesity is considered a chronic low-grade inflammatory state and the liver has been recognized as being an "immunological organ". The complex role of the immune system in the pathogenesis of NASH is currently raising great interest, also in view of the possible therapeutic potential of immunotherapy in NASH. This review focuses on the disturbances of the cells constituting the innate and adaptive immune system in the liver and in adipose tissue.

Variations of serum levels of adiponectin and resistin in chronic viral hepatitis

BACKGROUND AND AIMS

Several studies investigated the possible role of adipokines during chronic viral hepatitis, not producing defined results neither clearly establishing their behavior in course of anti-viral treatment. Our study evaluated blood concentrations of adiponectin and resistin in patients with chronic hepatitis C (CHC), B (CHB), and D (CHD) receiving anti-viral treatment, at baseline and after therapy.

METHODS

We examined 122 subjects, divided into two groups: 64 patients with chronic hepatitis C virus (HCV) infection (38 males and 26 females, mean age 47.25 yr) and 58 patients including 39 ones with chronic hepatitis B virus (HBV) infection (26 males and 13 females, mean age 48.46 yr) and 19 ones with chronic HBV-hepatitis D virus (HDV) infection (15 males and 4 females, mean age 45.79 yr). Serum levels of adiponectin and resistin were assayed by enzyme-linked immunosorbent assay.

RESULTS

In the group of CHC patients we observed a significant decrease in resistin after therapy (p=0.006), while not a significant increase in adiponectin after treatment (p=0.32). Evaluation of changes in adiponectin and resistin levels after anti-viral treatment, both in responders and non-responders, revealed no significant variations. In the group of HBV+ and HBV-HDV+ patients, we found a decrease in resistin after therapy (p=0.0016) and a not significant reduction in adiponectin after treatment (p=0.13). Furthermore, we noticed a significant reduction of resistin (p=0.006) in the sub-group of responders.

CONCLUSIONS

Our data suggested the possible marker role of adiponectin and resistin in the inflammatory process in course of chronic viral hepatitis.

Plasma insulin, leptin, adiponectin, resistin, ghrelin, and melatonin in nonalcoholic steatohepatitis patients treated with melatonin

Insulin resistance, oxidative stress, and an abnormal production of adipokines and cytokines are implicated in the pathogenesis of nonalcoholic steatohepatitis (NASH). Recently, we reported a significant improvement in plasma liver enzymes among patients with NASH treated with melatonin. In this study, we investigated the effect of melatonin, administered at a dose of 10 mg/day for 28 days to 16 patients with histologically proven NASH on insulin resistance (HOMA-IR), on the plasma levels of adiponectin, leptin, ghrelin, and resistin. Additionally, plasma levels of aminotransferases and gamma glutamyltranspeptidase as well as plasma concentrations of melatonin were evaluated. Median baseline values of HOMA-IR, leptin (ng/mL), and resistin (pg/mL) in patients with NASH were significantly higher in comparison with controls: 4.90 versus 1.60, 10.70 versus 4.30, and 152 versus 91, respectively. Median adiponectin level (μg/mL) was decreased in patients compared to controls: 6.40 versus 16.25; no significant difference in ghrelin levels between patients and controls was found. After melatonin treatment, the median value of HOMA-IR was significantly reduced by 60% as compared to baseline values, whereas adiponectin, leptin, and ghrelin plasma levels rose significantly by 119%, 33%, and 20%, respectively; the difference between pre-/posttreatment in plasma resistin levels was not significant. These findings make melatonin a suitable candidate for testing in patients with NASH in the large controlled clinical trials.

Oxidative stress in stable cystic fibrosis patients: do we need higher antioxidant plasma levels?

Oxidative stress plays an important role in cystic fibrosis (CF). However, there is a lack of validated biomarkers of oxidative damage that correlate with the antioxidant needs of patients with CF.

OBJECTIVE

To investigate oxidative stress in stable pediatric CF patients and evaluate if vitamin supplementation may be tailored to individual needs and oxidative status.

RESULTS

Lipid-adducts 4-hydroxynonenal (HNE-L) and malonaldehyde (MDA-L) (chromolipids) were elevated in the majority of patients despite normal plasma vitamin E, A and C. HNE-L and MDA-L increased with age, while plasma vitamins decreased. The most relevant correlation was identified between vitamin C and chromolipids. Patients with pancreatic insufficiency (PI) showed significantly higher plasma chromolipids despite no differences in plasma vitamins.

CONCLUSIONS

The majority of patients showed elevated plasma chromolipids that increased with age. Antioxidant vitamin reference ranges provide incomplete information on the redox status. CF patients with PI showed excessive oxidative stress damage.

Serum levels of leptin, adiponectin and resistin are interrelated and related to total antioxidant capacity, free fatty acids and phospholipids in early neonatal life

OBJECTIVES

The aims of this study were to determine interrelationships between serum leptin, adiponectin and resistin, insulin-like growth factor-1 (IGF-1), total antioxidant capacity (TAC), non-esterified fatty acids (NEFA) and phospholipids concentrations in infants.

DESIGN AND METHODS

A cross-sectional study was conducted to assess serum levels of leptin, adiponectin, resistin, IGF-1, TAC, NEFA and phospholipids in 45 breast-fed infants enrolled at 4-30 days after birth.

RESULTS

Serum leptin and adiponectin concentrations were positively correlated. Serum resistin concentrations were inversely correlated to serum leptin and adiponectin concentrations. Serum TAC was positively correlated to serum leptin and adiponectin, and inversely to serum resistin concentrations. Serum adiponectin concentrations were positively related to serum NEFA and phospholipid concentrations. Serum resistin concentrations were inversely related to serum NEFA, and phospholipid concentrations.

CONCLUSION

These data show that circulatory levels of leptin, adiponectin and resistin are interrelated and they apparently interact with the anti-oxidant system of infants.

Iron in fatty liver and in the metabolic syndrome: a promising therapeutic target

The dysmetabolic iron overload syndrome (DIOS) is now a frequent finding in the general population, as is detected in about one third of patients with nonalcoholic fatty liver disease (NAFLD) and the metabolic syndrome. The pathogenesis is related to altered regulation of iron transport associated with steatosis, insulin resistance, and subclinical inflammation, often in the presence of predisposing genetic factors. Evidence is accumulating that excessive body iron plays a causal role in insulin resistance through still undefined mechanisms that probably involve a reduced ability to burn carbohydrates and altered function of adipose tissue. Furthermore, DIOS may facilitate the evolution to type 2 diabetes by altering beta-cell function, the progression of cardiovascular disease by contributing to the recruitment and activation of macrophages within arterial lesions, and the natural history of liver disease by inducing oxidative stress in hepatocytes, activation of hepatic stellate cells, and malignant transformation by promotion of cell growth and DNA damage. Based on these premises, the association among DIOS, metabolic syndrome, and NAFLD is being investigated as a new risk factor to predict the development of overt cardiovascular and hepatic diseases, and possibly hepatocellular carcinoma, but most importantly, represents also a treatable condition. Indeed, iron depletion, most frequently achieved by phlebotomy, has been shown to decrease metabolic alterations and liver enzymes in controlled studies in NAFLD. Additional studies are warranted to evaluate the potential of iron reductive therapy on hard clinical outcomes in patients with DIOS.

Factors associated with hepatic steatosis in obese children and adolescents

OBJECTIVES

Obesity is associated with high prevalence of hepatic steatosis. We speculate that determinant factors of susceptibility to hepatic steatosis in obesity could differ between children and adolescents.

PATIENTS AND METHODS

Blood biochemical parameters, systemic oxidative stress markers, proinflammatory cytokines, and adipokine levels were determined in 157 obese children and adolescents. The subjects were divided into 2 groups: children and adolescents, identified as such in accordance with Tanner stage and the measured level of dehydroepiandrosterone sulphate. Steatosis was evaluated by ultrasonography in 127 subjects.

RESULTS

Steatosis prevalence was 44.8%. In the "children" group, those with hepatic steatosis presented higher levels of erythrocyte oxidised glutathione (GSSG) and resistin, lower levels of high-density lipoprotein (HDL) cholesterol, and lower enzymatic activities of erythrocyte glutathione reductase (GRd) and glutathione oxidase (GPx). In the "adolescents" group, those with hepatic steatosis presented higher values for body mass index z score (BMIz), insulin, peptide C, homeostatic model assessment index (HOMA-IR), alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglycerides, GSSG, and leptin. These subjects also presented lower values for soluble leptin receptor, GRd, and GPx. In the "children" group, the only independent factor of steatosis was a decrease in GRd activity (odds ratio [OR] 0.165, 95% CI 0.03-0.84, P = 0.030). Moreover, in the "adolescent" group, the independent factors were higher for GSSG (OR 6.8, 95% CI 1.6-28.7, P = 0.010) and HOMA-IR (OR 1.9, 95% CI 1.17-3.1, P = 0.009).

CONCLUSIONS

Factors associated with hepatic steatosis differ between obese children and adolescents. Oxidative stress is seen to be the main process in children, whereas in adolescents oxidative stress and insulin resistance are significant factors for steatosis.

The role of resistin as a regulator of inflammation: Implications for various human pathologies

Resistin was originally described as an adipocyte-secreted peptide that induced insulin resistance in rodents. Increasing evidence indicates its important regulatory roles in various biological processes, including several inflammatory diseases. Further studies have shown that resistin in humans, in contrast to its production by adipocytes in mice, is synthesized predominantly by mononuclear cells both within and outside adipose tissue. Possible roles for resistin in obesity-related subclinical inflammation, atherosclerosis and cardiovascular disease, non-alcoholic fatty liver disease, rheumatic diseases, malignant tumors, asthma, inflammatory bowel disease, and chronic kidney disease have already been demonstrated. In addition, resistin can modulate several molecular pathways involved in metabolic, inflammatory, and autoimmune diseases. In this review, current knowledge about the functions and pathophysiological implications of resistin in different human pathologies is summarized, although there is a significant lack of firm evidence regarding the specific role resistin plays in the "orchestra" of the numerous mediators of inflammation.

Antioxidant supplemention in the treatment of skeletal muscle insulin resistance: potential mechanisms and clinical relevance

The incidence of type 2 diabetes has increased dramatically over the past several decades and this trend is projected to continue into the foreseeable future. Skeletal muscle insulin resistance is thought to be a key development in the pathogenesis of type 2 diabetes. Given this fact, interventions that prevent or reverse impairments in skeletal muscle action can have profound effects on whole-body glucose homeostasis. Traditional approaches used in this regard include exercise, weight loss, and insulin-sensitizing drugs such as thiazolidinediones (TZDs). Although these interventions have proven effective in improving glucose homeostasis, there are adherence issues seen with lifestyle interventions and undesirable side effects have been reported with TZDs. With these points in mind, the development of alternative strategies to maintain or improve skeletal muscle insulin sensitivity is warranted. In this context, the purpose of the present review is to highlight the role of antioxidant compounds in the prevention and treatment of skeletal muscle insulin resistance. Specifically, we will briefly describe the mechanisms of insulin-stimulated skeletal muscle glucose uptake and the potential mediators of oxidative stress induced insulin resistance, highlight data suggesting that antioxidant compounds can have beneficial effects on skeletal muscle insulin action, and discuss potential mechanisms mediating this effect.