Effects of vitamin E and glutathione on glucose metabolism: role of magnesium

Invited review: Camel milk-derived bioactive peptides and diabetes-Molecular view and perspectives

In dairy science, camel milk (CM) constitutes a center of interest for scientists due to its known beneficial effect on diabetes as demonstrated in many in vitro, in vivo, and clinical studies and trials. Overall, CM had positive effects on various parameters related to glucose transport and metabolism as well as the structural and functional properties of the pancreatic β-cells and insulin secretion. Thus, CM consumption may help manage diabetes; however, such a recommendation will become rationale and clinically conceivable only if the exact molecular mechanisms and pathways involved at the cellular levels are well understood. Moreover, the application of CM as an alternative antidiabetic tool may first require the identification of the exact bioactive molecules behind such antidiabetic properties. In this review, we describe the advances in our knowledge of the molecular mechanisms reported to be involved in the beneficial effects of CM in managing diabetes using different in vitro and in vivo models. This mainly includes the effects of CM on the different molecular pathways controlling (1) insulin receptor signaling and glucose uptake, (2) the pancreatic β-cell structure and function, and (3) the activity of key metabolic enzymes in glucose metabolism. Moreover, we described the current status of the identification of CM-derived bioactive peptides and their structure-activity relationship study and characterization in the context of molecular markers related to diabetes. Such an overview will not only enrich our scientific knowledge of the plausible mode of action of CM in diabetes but should ultimately rationalize the claim of the potential application of CM against diabetes. This will pave the way toward new directions and ideas for developing a new generation of antidiabetic products taking benefits from the chemical composition of CM.

Effect of vitamin B2, vitamin C, vitamin D, vitamin E and folic acid in adults with essential hypertension: a systematic review and network meta-analysis

OBJECTIVES

The objective of the current study is to compare the treatment effects of different vitamins on essential hypertension to provide an initial basis for developing evidence-based practices.

DESIGN

Systematic review and network meta-analysis.

DATA SOURCES

Five electronic databases (PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials and ClinicalTrials.gov) were searched from their inception to 25 September 2023.

OUTCOMES

The primary outcomes were the difference between the intervention group and the control group in changes in office systolic blood pressure (SBP) and office diastolic blood pressure (DBP) from baseline. The secondary outcomes were the difference between the intervention group and the control group in changes in 24-hour mean ambulatory systolic blood pressure (24 hours SBP), 24-hour mean ambulatory diastolic blood pressure (24 hours DBP) and heart rate (HR) from baseline.

RESULTS

A total of 23 studies comparing five vitamins (vitamin B2, vitamin C, vitamin D, vitamin E, folic acid) and involving 2218 participants were included. The included trials were all vitamin versus placebo, so the network was star-shaped. Among the five vitamins, only vitamin E was significantly more effective at reducing SBP (mean difference: -14.14 mm Hg, 95% credible intervals: -27.62 to -0.88) than placebo. In addition, no evidence was found that any of the five vitamins influenced DBP, 24 hours SBP, 24 hours DBP, or HR. The dose of vitamins, geographical region and percentage of males (only SBP) might be sources of heterogeneity. Sensitivity and subgroup analysis revealed that the effect of vitamin intervention on blood pressure varies according to different doses of vitamins.

CONCLUSIONS

According to the results, vitamin E might be an effective measure to reduce SBP, but more research is needed to validate this finding.

PROSPERO REGISTRATION NUMBER

CRD42022352332.

Magnesium Supplementation Alleviates the Toxic Effects of Silica Nanoparticles on the Kidneys, Liver, and Adrenal Glands in Rats

Concerns regarding the possible hazards to human health have been raised by the growing usage of silica nanoparticles (SiNPs) in a variety of applications, including industrial, agricultural, and medical applications. This in vivo subchronic study was conducted to assess the following: (1) the toxicity of orally administered SiNPs on the liver, kidneys, and adrenal glands; (2) the relationship between SiNPs exposure and oxidative stress; and (3) the role of magnesium in mitigating these toxic effects. A total of 24 Sprague Dawley male adult rats were divided equally into four groups, as follows: control group, magnesium (Mg) group (50 mg/kg/d), SiNPs group (100 mg/kg/d), and SiNPs+ Mg group. Rats were treated with SiNPs by oral gavage for 90 days. The liver transaminases, serum creatinine, and cortisol levels were evaluated. The tissue malondialdehyde (MDA) and reduced glutathione (GSH) levels were measured. Additionally, the weight of the organs and the histopathological changes were examined. Our results demonstrated that SiNPs exposure caused increased weight in the kidneys and adrenal glands. Exposure to SiNPs was also associated with significant alterations in liver transaminases, serum creatinine, cortisol, MDA, and GSH. Additionally, histopathological changes were significantly reported in the liver, kidneys, and adrenal glands of SiNPs-treated rats. Notably, when we compared the control group with the treated groups with SiNPs and Mg, the results revealed that magnesium could mitigate SiNPs-induced biochemical and histopathologic changes, confirming its effective role as an antioxidant that reduced the accumulation of SiNPs in tissues, and that it returns the levels of liver transaminases, serum creatinine, cortisol, MDA, and GSH to almost normal values.

Dietary Supplements Potentially Target Plasma Glutathione Levels to Improve Cardiometabolic Health in Patients with Diabetes Mellitus: A Systematic Review of Randomized Clinical Trials

Cardiovascular diseases (CVDs) continue to be the leading cause of death in people with diabetes mellitus. Severely suppressed intracellular antioxidant defenses, including low plasma glutathione (GSH) levels, are consistently linked with the pathological features of diabetes such as oxidative stress and inflammation. In fact, it has already been established that low plasma GSH levels are associated with increased risk of CVD in people with diabetes. Dietary supplements are widely used and may offer therapeutic benefits for people with diabetes at an increased risk of developing CVDs. However, such information remains to be thoroughly scrutinized. Hence, the current systematic review explored prominent search engines, including PubMed and Google Scholar, for updated literature from randomized clinical trials reporting on the effects of dietary supplements on plasma GSH levels in people with diabetes. Available evidence indicates that dietary supplements, such as coenzyme Q10, selenium, curcumin, omega-3 fatty acids, and vitamin E or D, may potentially improve cardiometabolic health in patients with diabetes. Such beneficial effects are related to enhancing plasma GSH levels and reducing cholesterol, including biomarkers of oxidative stress and inflammation. However, available evidence is very limited and additional clinical studies are still required to validate these findings, including resolving issues related to the bioavailability of these bioactive compounds.

Camel milk protectiveness toward multiple liver disorders: A review

Camel milk is known as the white gold of the desert because it contains within it a variety of nutrients which play a key role in the human diet. The health benefits of camel milk have been described for a variety of diseases such as diabetes, kidney disease, hepatitis, etc. including improved overall survival. A major health burden worldwide is liver diseases, and the ninth leading cause of death in Western countries is due to liver cirrhosis. Treatment is mostly ineffective for cirrhosis, fatty liver, and chronic hepatitis which are the most common diseases of the liver; furthermore current treatments carry the risk of side effects, and are often extremely expensive, particularly in the developing world. A systematic review of studies was performed to determine the association of consumption of camel milk on multiple diseases of the liver. The impact of camel milk on the laboratory tests related to the liver disorders, viral hepatitis, non-alcoholic fatty liver disease (NAFLD), cirrhosis, and hepatocellular carcinoma (HCC) were evaluated. The consumption of camel milk was accompanied by modulation of the values of serum gamma-glutamyl transferase, aspartate aminotransferase, and alanine aminotransferase in persons who are at risk of liver disease. In the patients with chronic liver disease, it was observed that they have low rates of mortality and low chances of progression to cirrhosis when they consume camel milk. Therefore, in patients with liver diseases, the addition of camel milk to their normal daily diet plan should be encouraged. In this review, camel milk's impact on the different kinds of liver diseases or any disorder associated with liver functioning was evaluated. Camel milk has a therapeutic as well as a preventive role in the maintenance and improving the metabolic regulations of the body.

The effect of magnesium alone or its combination with other supplements on the markers of inflammation, OS and metabolism in women with polycystic ovarian syndrome (PCOS): A systematic review

The objective of this systematic review is to synthesize the available evidence on the effectiveness of magnesium supplements on the markers of inflammation, oxidative stress (OS), and metabolism in PCOS patients and to provide a basis for its clinical treatment. Electronic databases (PubMed, Cochrane Library databases, Embase, Web of science, CMB, CNKI, VIP, Wan Fang and ClinicalTrials.gov) were searched from their inception until January 2022. Randomized controlled trials (RCTs) for PCOS undergoing therapy with magnesium supplementation alone or in combination with other agents. The primary outcomes were the markers of blood glucose and OS.363 patients from nine RCTs were included in the current systematic review. Four of the nine studies reported the effects of magnesium supplementation alone on OS or metabolic markers in women with PCOS. Whilemagnesium supplementation alone did not show any significant improvement in the markers of inflammation, OS or metabolism in PCOS, seven of the nine articles reported the effect of magnesium co-supplementation on OS or metabolic markers in PCOS patients. Magnesium combined with vitamin E or zinc-calcium-vitamin D significantly improved glucose and lipid metabolism in PCOS patients. Magnesium intake alone did not lead to a significant improvement in the markers of OS, blood glucose, or serum lipids in PCOS. However, magnesium combined with other supplements (vitamin E, zinc, zinc-calcium-vitamin D) significantly improved serum hs-CRP, insulin, HOMA-IR, TG, TC levels, and the improvement in OS markers was inconclusive. The effect of magnesium and melatonin supplementation on the markers of metabolism needs to be further verified.

SYSTEM REVIEW REGISTRATION

PROSPERO https://www.crd.york.ac.uk/PROSPERO/#myprospero, CRD42022303410.

The effects of vitamin and mineral supplementation on women with gestational diabetes mellitus

BACKGROUND

The effects of vitamin and mineral supplementation on women with gestational diabetes mellitus (GDM) have not been well established. We conduct a meta-analysis to evaluate the effects of vitamin and mineral supplementation on glycemic control, inflammation and oxidative stress for women with GDM.

METHODS

A systematic search of randomized controlled trials (RCTs) was conducted from PubMed, Embase, Web of Science and Cochrane Library up to July, 2020. Various results were pooled by using Review manager 5.3 and Stata 12.0. Mean difference (MD) with 95% confidence interval (CI) was estimated. Heterogeneity between studies was assessed by I-squared (I²) tests.

RESULTS

Six hundred ninety-eight patients from 12 trials were included in our meta-analysis. Magnesium, zinc, selenium, calcium, vitamin D and E (alone or in combination) were found to significantly improve glycemic control in women with GDM compared to those receiving placebos: fasting plasma glucose (FPG) (MD = - 9.02; 95% CI: - 12.09, - 5.96; P < 0.00001), serum insulin (MD = - 4.33; 95% CI: - 5.35, - 3.32; P < 0.00001), homeostasis model assessment-insulin resistance (HOMA-IR) (MD = - 1.34; 95% CI: - 1.60, - 1.07; P < 0.00001), and homeostasis model of assessment for β cell function (HOMA-B) (MD = - 15.58; 95% CI: - 23.70, - 7.46; P = 0.0002). Vitamin and mineral supplementation was found to attenuated inflammation and oxidative stress through decreasing high-sensitivity C-reactive protein (hs-CRP) (MD = - 1.29; 95% CI: - 1.82, - 0.76; P < 0.00001), malondialdehyde (MDA) (MD = - 0.71; 95% CI: - 0.97, - 0.45; P < 0.00001), and increasing total antioxidant capacity (TAC) (MD = 45.55; 95% CI: 22.02, 69.08; P = 0.0001).

CONCLUSIONS

This meta-analysis shows that vitamin and mineral supplementation significantly improved glycemic control, attenuated inflammation and oxidative stress in women with GDM.

Sidr honey abrogates the oxidative stress and downregulates the hyaluronic acid concentration and gene expression of TGF-β1 and COL1a1 in rat model of thioacetamide-induced hepatic fibrosis

Liver fibrosis is a major health concern, which might progress to cirrhosis. To date, treatment trials rely mainly on the removal of the causative factor. The current study investigated the potential ameliorative role of sidr honey on thioacetamide (TAA)-induced liver fibrosis in rats. Forty-eight Wistar albino rats were equally allocated into four groups: control; sidr honey (5g/kg body weight (BW), orally); TAA (200 mg/kg BW, IP three times weekly/15 weeks); and sidr honey plus TAA at the same dose and administration rout. Rats co-treated with sidr honey plus TAA revealed significant reduction in hepatic malondialdehyde, hyaluronic acid (HA), alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, gamma glutamyl transferase, direct bilirubin, and hepatic mRNA expression of transforming growth factor (TGF)-β1 and collagen type I alpha 1 chain (COL1a1) compared to TAA-exposed rats. In addition, the hepatoprotective potential of sidr honey was indicated via improvement of histopathologic picture of hepatocytes and upregulation of total antioxidant capacity, reduced glutathione, catalase, glutathione peroxidase, superoxide dismutase, total protein, and albumin compared to TAA-treated rats. In conclusion, daily administration of sidr honey (5 g/kg BW) is a promising natural antioxidant and fibrosuppressive agent that could ameliorate liver fibrosis via downregulation of fibrosis genes including TGF-β1 and COL1a1 and HA and via enhancement of antioxidant system.

Exposure to Static Magnetic and Electric Fields Treats Type 2 Diabetes

Aberrant redox signaling underlies the pathophysiology of many chronic metabolic diseases, including type 2 diabetes (T2D). Methodologies aimed at rebalancing systemic redox homeostasis have had limited success. A noninvasive, sustained approach would enable the long-term control of redox signaling for the treatment of T2D. We report that static magnetic and electric fields (sBE) noninvasively modulate the systemic GSH-to-GSSG redox couple to promote a healthier systemic redox environment that is reducing. Strikingly, when applied to mouse models of T2D, sBE rapidly ameliorates insulin resistance and glucose intolerance in as few as 3 days with no observed adverse effects. Scavenging paramagnetic byproducts of oxygen metabolism with SOD2 in hepatic mitochondria fully abolishes these insulin sensitizing effects, demonstrating that mitochondrial superoxide mediates induction of these therapeutic changes. Our findings introduce a remarkable redox-modulating phenomenon that exploits endogenous electromagneto-receptive mechanisms for the noninvasive treatment of T2D, and potentially other redox-related diseases.

Cardiovascular and Metabolic Protection by Vitamin E: A Matter of Treatment Strategy?

Cardiovascular diseases (CVD) cause about 1/3 of global deaths. Therefore, new strategies for the prevention and treatment of cardiovascular events are highly sought-after. Vitamin E is known for significant antioxidative and anti-inflammatory properties, and has been studied in the prevention of CVD, supported by findings that vitamin E deficiency is associated with increased risk of cardiovascular events. However, randomized controlled trials in humans reveal conflicting and ultimately disappointing results regarding the reduction of cardiovascular events with vitamin E supplementation. As we discuss in detail, this outcome is strongly affected by study design, cohort selection, co-morbidities, genetic variations, age, and gender. For effective chronic primary and secondary prevention by vitamin E, oxidative and inflammatory status might not have been sufficiently antagonized. In contrast, acute administration of vitamin E may be more translatable into positive clinical outcomes. In patients with myocardial infarction (MI), which is associated with severe oxidative and inflammatory reactions, decreased plasma levels of vitamin E have been found. The offsetting of this acute vitamin E deficiency via short-term treatment in MI has shown promising results, and, thus, acute medication, rather than chronic supplementation, with vitamin E might revitalize vitamin E therapy and even provide positive clinical outcomes.

Magnesium, Oxidative Stress, Inflammation, and Cardiovascular Disease

Hypomagnesemia is commonly observed in heart failure, diabetes mellitus, hypertension, and cardiovascular diseases. Low serum magnesium (Mg) is a predictor for cardiovascular and all-cause mortality and treating Mg deficiency may help prevent cardiovascular disease. In this review, we discuss the possible mechanisms by which Mg deficiency plays detrimental roles in cardiovascular diseases and review the results of clinical trials of Mg supplementation for heart failure, arrhythmias and other cardiovascular diseases.

Nutrient pattern of unsaturated fatty acids and vitamin E increase resting metabolic rate of overweight and obese women

Objectives: Obesity plays an important role in the development of chronic diseases including cardiovascular disease and diabetes. A low resting metabolic rate (RMR) for a given body size and composition is a risk factor for obesity, however, there is limited evidence available regarding the association of nutrient patterns and RMR. The aim of this study was to determine the association of nutrient patterns and RMR in overweight and obese women. Study design: This cross-sectional study was conducted on 360 women who were overweight or obese. Method: Dietary intake was assessed using a semi-quantitative standard food frequency questionnaire (FFQ). Nutrient patterns were also extracted by principal components analysis (PCA). All participants were evaluated for their body composition, RMR, and blood parameters. Result: Three nutrient patterns explaining 64% of the variance in dietary nutrients consumption were identified as B-complex-mineral, antioxidant, and unsaturated fatty acid and vitamin E (USFA-vit E) respectively. Participants were categorized into two groups based on the nutrient patterns. High scores of USFA-vit E pattern was significantly associated with the increase of RMR (β = 0.13, 95% CI = 0.79 to 68.16, p = 0.04). No significant associations were found among B-complex-mineral pattern (β = -0.00, 95% CI = -49.67 to 46.03, p = 0.94) and antioxidant pattern (β = 0.03, 95% CI -41.42 to 22.59, p = 0.56) with RMR. Conclusion: Our results suggested that the "USFA-vit E" pattern (such as PUFA, oleic, linoleic, vit.E, α-tocopherol and EPA) was associated with increased RMR.

Effect of vitamin C and E on oxidative stress and antioxidant system in the salivary glands of STZ-induced diabetic rats

OBJECTIVE

We examined the effects of vitamin C and E supplementation in the prevention of oxidative stress in the salivary glands of STZ-induced diabetic rats.

DESIGN

Forty-eight male Wistar rats were divided into six groups (n = 8 in each): control (C), control supplemented with vitamin C (Cvc) and E (Cve), diabetic (D), and diabetic supplemented with vitamin C (Dvc) and E (Dve). Vitamin C (150 mg/kg) and E (300 mg/kg) were daily administered for 21 days. Serum ascorbic acid and α-tocopherol levels were quantified. Glandular levels of hydrogen peroxide (H₂O₂), superoxide anion (O₂^-), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT), malondialdehyde (MDA) and the total antioxidant status (TAS) were estimated.

RESULTS

Vitamin C and E levels were reduced in D group. Vitamin C decreased the levels of O₂^- in the salivary gland of diabetic rats. Vitamin E increased the concentration of O₂^- in PA gland of diabetic animals. In the SM gland of the diabetic group, MDA, SOD, GPx and TAS increased. Dve presented reduced SOD activity and increased GR, GPx, and MDA. Dve increased GPx, Gr and TAS levels. In the PA gland, MDA, SOD, CAT, GPx, GR, and TAS were similar in C and D. TAS, SOD, CAT, GPx, and GR increased in Dvc. Vitamin E supplementation resulted in increased MDA and CAT levels and reduced SOD activity.

CONCLUSION

In the SM glands of the diabetic rats, vitamin C supplementation improved the antioxidant system, while vitamin E acted as pro-oxidant.

Impact of Camel's Milk on Aluminum Chloride (Alcl3) - Induced Toxicity in Rats

The present study was carried out to evaluate the efficiency of camel's milk to ameliorate the toxicity of aluminum chloride AlCl3 on some hematological parameters; hepatic,renal functions andlipids profile; as well ashistopathological alterations of some organs. Forty rats (8 / group) were divided into 5 treatment groups:Group1: Normal rats (negative control); Group2: AlCl3induced toxicity rats (positive control); Group3: AlCl3induced toxicity rats fed with raw camel milk; Group4: AlCl3 induced toxicity rats fed with heat treated camel milk; andGroup5: AlCl3 induced toxicity rats fed with sweet acidophilus camel milk.Rats were treatedby 5ml camel’s milk 10 min before the administration of 1 ml AlCl3 (0.5 mg / kgbody weight); and had their respective doses daily for 30 successive days orally. AlCl3 oral administration resulted in a significant decrease in red blood cells count (RBC's), significant increase in mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH); while hemoglobin (Hb), hematocrite (Hct), platelets(plt), reticulocytes (Ret), mean corpuscular hemoglobin concentration (MCHC) did not revealed significant changes; the obtained anemia was macrocytic normochromic. The lipids profile; hepatic and renal functions showed non significant changes between different groups; however, histopathological examination showed variable alterations of varying severity in some organs; besides their response to camel's milk administration. Camel’s milk administration in groups 3, 4, 5 alleviated the toxic effect of AlCl3 with variable degrees between different groups.

The Effects of Magnesium and Vitamin E Co-Supplementation on Hormonal Status and Biomarkers of Inflammation and Oxidative Stress in Women with Polycystic Ovary Syndrome

Synergistic approach of magnesium and vitamin E may benefit clinical symptoms of patients with polycystic ovary syndrome (PCOS) through improving their metabolic profiles and reducing oxidative stress and inflammation. This study was designed to determine the effects of magnesium and vitamin E co-supplementation on hormonal status and biomarkers of inflammation and oxidative stress in women with PCOS. This randomized, double-blind, placebo-controlled trial was conducted among 60 women with PCOS, aged 18-40 years old. Participants were randomly divided into two groups to take 250 mg/day magnesium plus 400 mg/day vitamin E supplements or placebo (n = 30 each group) for 12 weeks. Fasting blood samples were taken at baseline and after the 12-week intervention to quantify related variables. Magnesium and vitamin E co-supplementation resulted in a significant reduction in hirsutism (β - 0.37; 95% CI, - 0.70, - 0.05; P = 0.02) and serum high-sensitivity C-reactive protein (hs-CRP) (β - 0.67 mg/L; 95% CI, - 1.20, - 0.14; P = 0.01), and a significant increase in plasma nitric oxide (NO) (β 3.40 μmol/L; 95% CI, 1.46, 5.35; P = 0.001) and total antioxidant capacity (TAC) levels (β 66.32 mmol/L; 95% CI, 43.80, 88.84; P < 0.001). Overall, magnesium and vitamin E co-supplementation for 12 weeks may benefit women with PCOS on hirsutism, serum hs-CRP, plasma NO, and TAC levels. Clinical trial registration number http://www.irct.ir : IRCT2017082733941N8.

The effects of magnesium and vitamin E co-supplementation on wound healing and metabolic status in patients with diabetic foot ulcer: A randomized, double-blind, placebo-controlled trial

This study was carried out to determine the effects of magnesium and vitamin E co-supplementation on wound healing and metabolic status in patients with diabetic foot ulcer (DFU). The current randomized, double-blind, placebo-controlled trial was conducted among 57 patients with grade 3 DFU. Participants were randomly divided into two groups to take either 250 mg magnesium oxide plus 400 IU vitamin E (n = 29) or placebo per day (n = 28) for 12 weeks. Compared with the placebo, taking magnesium plus vitamin E supplements reduced ulcer length (β [difference in the mean of outcomes measures between treatment groups] -0.56 cm; 95% CI, -0.92, -0.20; p = 0.003), width (β -0.35 cm; 95% CI, -0.64, -0.05; p = 0.02) and depth (β -0.18 cm; 95% CI, -0.33, -0.02; p = 0.02). In addition, co-supplementation led to a significant reduction in fasting plasma glucose (β -13.41 mg/dL; 95% CI, -20.96, -5.86; p = 0.001), insulin (β -1.45 μIU/ml; 95% CI, -2.37, -0.52; p = 0.003), insulin resistance (β -0.60; 95% CI, -0.99, -0.20; p = 0.003) and HbA1c (β -0.32%; 95% CI, -0.48, -0.16; p < 0.003), and a significant elevation in insulin sensitivity (β 0.007; 95% CI, 0.003, 0.01; p < 0.001) compared with the placebo. Additionally, compared with the placebo, taking magnesium plus vitamin E supplements decreased triglycerides (β -10.08 mg/dL; 95% CI, -19.70, -0.46; p = 0.04), LDL-cholesterol (β -5.88 mg/dL; 95% CI, -11.42, -0.34; p = 0.03), high sensitivity C-reactive protein (hs-CRP) (β -3.42 mg/L; 95% CI, -4.44, -2.41; p < 0.001) and malondialdehyde (MDA) (β -0.30 μmol/L; 95% CI, -0.45, -0.15; p < 0.001), and increased HDL-cholesterol (β 2.62 mg/dL; 95% CI, 0.60, 4.63; p = 0.01) and total antioxidant capacity (TAC) levels (β 53.61 mmol/L; 95% CI, 4.65, 102.57; p = 0.03). Overall, magnesium and vitamin E co-supplementation for 12 weeks to patients with DFU had beneficial effects on ulcer size, glycemic control, triglycerides, LDL- and HDL-cholesterol, hs-CRP, TAC, and MDA levels.

Genetic polymorphisms associated with reactive oxygen species and blood pressure regulation

Hypertension is the most prevalent cause of cardiovascular disease and kidney failure, but only about 50% of patients achieve adequate blood pressure control, in part, due to inter-individual genetic variations in the response to antihypertensive medication. Significant strides have been made toward the understanding of the role of reactive oxygen species (ROS) in the regulation of the cardiovascular system. However, the role of ROS in human hypertension is still unclear. Polymorphisms of some genes involved in the regulation of ROS production are associated with hypertension, suggesting their potential influence on blood pressure control and response to antihypertensive medication. This review provides an update on the genes associated with the regulation of ROS production in hypertension and discusses the controversies on the use of antioxidants in the treatment of hypertension, including the antioxidant effects of antihypertensive drugs.

The Effect of Magnesium and Vitamin E Co-Supplementation on Glycemic Control and Markers of Cardio-Metabolic Risk in Women with Polycystic Ovary Syndrome: A Randomized, Double-Blind, Placebo-Controlled Trial

Data on the effects of magnesium and vitamin E co-supplementation on glycemic control and markers of cardio-metabolic risk of patients with polycystic ovary syndrome (PCOS) were collected. This investigation was conducted to evaluate the effects of magnesium and vitamin E co-supplementation on glycemic control and markers of cardio-metabolic risk in women with PCOS. This randomized, double-blind, placebo-controlled trial was carried out on 60 women with PCOS, aged 18-40 years old. Participants were randomly divided into two groups to receive 250 mg/day magnesium plus 400 mg/day vitamin E supplements or placebo (n=30 each group) for 12 weeks. Fasting blood samples were taken at baseline and after the 12-week intervention to quantify related variables. After the 12-week intervention, compared with the placebo, magnesium and vitamin E co-supplementation led to a significant reduction in serum insulin levels (-1.1±3.0 vs. +1.6±3.7 μIU/ml, p=0.003) and homeostatic model of assessment for insulin resistance (-0.2±0.7 vs. +0.4±0.9, p=0.002), and a significant increase in the quantitative insulin sensitivity check index (+0.01±0.01 vs. -0.009±0.02, p=0.003). Furthermore, magnesium plus vitamin E supplementation significantly decreased serum triglycerides (-15.0±24.4 vs. +6.7±22.2 mg/dl, p=0.001) and VLDL-cholesterol concentrations (-3.0±4.9 vs. +0.6±2.4 mg/dl, P=0.01) compared with the placebo. A trend toward a greater decrease in total cholesterol levels was observed in magnesium plus vitamin E group compared to placebo group (-7.0±32.6 vs. +8.1±26.6 mg/dl, p=0.05). In conclusion, magnesium and vitamin E co-supplementation for 12 weeks to PCOS women had beneficial effects on parameters of insulin metabolism and few markers of cardio-metabolic risk.

The effects of magnesium and vitamin E co-supplementation on parameters of glucose homeostasis and lipid profiles in patients with gestational diabetes

BACKGROUND

Magnesium and vitamin E are known to exert multiple beneficial effects, such as anti-glycemic and anti-lipidemic properties. The aim of this study was to determine the effects of magnesium and vitamin E co-supplementation on metabolic status of women with gestational diabetes (GDM).

METHODS

This randomized, double-blinded, placebo-controlled trial was conducted among 60 subjects diagnosed with GDM, aged 18-40 years. Subjects were randomly allocated into two groups to receive 250 mg/day magnesium oxide plus 400 IU/day vitamin E supplements or placebo (n = 30 each group) for 6 weeks. Participants' blood samples were taken to determine their metabolic profiles.

RESULTS

Subjects who received magnesium plus vitamin E supplements had significantly lower fasting plasma glucose (β - 5.20 mg/dL; 95% CI, - 7.88, - 2.52; P = 0.002), serum insulin levels (β - 2.93 μIU/mL; 95% CI, - 5.68, - 0.18; P = 0.02) and homeostasis model of assessment-insulin resistance (β - 0.78; 95% CI, - 1.42, - 0.14; P = 0.01), and higher quantitative insulin sensitivity check index (β 0.01; 95% CI, 0.005, 0.02; P = 0.002) compared with placebo. In addition, magnesium plus vitamin E supplementation resulted in a significant reduction in serum triglycerides (β - 50.31 mg/dL; 95% CI, - 67.58, - 33.04; P < 0.001), VLDL- (β - 10.06 mg/dL; 95% CI, - 13.51, - 6.60; P < 0.001), total- (β - 26.10 mg/dL; 95% CI, - 41.88, - 10.33; P = 0.004), LDL- (β - 15.20 mg/dL; 95% CI, - 29.50, - 0.91; P = 0.03) and total-/HDL-cholesterol ratio (β - 0.46; 95% CI, - 0.72, - 0.19; P < 0.001) compared with placebo. Magnesium and vitamin E co-supplementation did not affect HDL-cholesterol levels.

CONCLUSIONS

Overall, magnesium and vitamin E co-supplementation for 6 weeks in women with GDM significantly improved glycemic control and lipid profiles, except for HDL-cholesterol levels.

CLINICAL TRIAL REGISTRATION NUMBER

http://www.irct.ir : IRCT20170513033941N24.

Vitamin E Modifies High-Fat Diet-Induced Increase of DNA Strand Breaks, and Changes in Expression and DNA Methylation of Dnmt1 and MLH1 in C57BL/6J Male Mice

Obesity is associated with low-grade inflammation, increased ROS production and DNA damage. Supplementation with antioxidants might ameliorate DNA damage and support epigenetic regulation of DNA repair. C57BL/6J male mice were fed a high-fat (HFD) or a control diet (CD) with and without vitamin E supplementation (4.5 mg/kg body weight (b.w.)) for four months. DNA damage, DNA promoter methylation and gene expression of Dnmt1 and a DNA repair gene (MLH1) were assayed in liver and colon. The HFD resulted in organ specific changes in DNA damage, the epigenetically important Dnmt1 gene, and the DNA repair gene MLH1. Vitamin E reduced DNA damage and showed organ-specific effects on MLH1 and Dnmt1 gene expression and methylation. These results suggest that interventions with antioxidants and epigenetic active food ingredients should be developed as an effective prevention for obesity—and oxidative stress—induced health risks.

The Effects of Omega-3 Fatty Acids and Vitamin E Co-Supplementation on Indices of Insulin Resistance and Hormonal Parameters in Patients with Polycystic Ovary Syndrome: A Randomized, Double-Blind, Placebo-Controlled Trial

This study was conducted to determine the effects of omega-3 fatty acids and vitamin E co-supplementation on indices of insulin resistance and hormonal parameters in women with polycystic ovary syndrome (PCOS). This randomized double-blind, placebo-controlled trial was done on 68 women diagnosed with PCOS according to the Rotterdam criteria aged 18-40 years old. Participants were randomly assigned into 2 groups to receive either 1 000 mg omega-3 fatty acids from flaxseed oil containing 400 mg α-Linolenic acid plus 400 IU vitamin E supplements (n=34) or placebo (n=34) for 12 weeks. Hormonal parameters were quantified at the beginning of the study and after 12-week intervention. After 12 weeks of intervention, compared to the placebo, omega-3 fatty acids and vitamin E co-supplementation resulted in a significant decrease in insulin (-1.0±3.5 vs. +2.7±6.6 µIU/mL, P=0.004), homeostasis model of assessment-estimated insulin resistance (-0.2±0.8 vs. +0.6±1.5, P=0.005), homeostasis model of assessment-estimated B cell function (-4.3±14.3 vs. +10.5±24.5, P=0.004) and a significant increase in quantitative insulin sensitivity check index (+0.006±0.02 vs. -0.01±0.04, P=0.008). Supplementation with omega-3 fatty acids plus vitamin E led to significant reductions in serum total testosterone (-0.5±0.7 vs. -0.1±0.5 ng/mL, P=0.008) and free testosterone (-1.2±2.1 vs. -0.2±1.7, P=0.04) compared to the placebo group. We did not observe any significant effect of omega-3 fatty acids and vitamin E co-supplementation on fasting plasma glucose and other hormonal profiles. Omega-3 fatty acids and vitamin E co-supplementation for 12 weeks in PCOS women significantly improved indices of insulin resistance, total and free testosterone.

Camel milk and bee honey regulate profibrotic cytokine gene transcripts in liver cirrhosis induced by carbon tetrachloride

The lack of studies regarding the mechanism of the protective effects of camel milk and bee honey against hepatotoxic compounds led us to perform this study. Thirty-six male rats were divided into two main groups. The first group (n = 9) comprised control non-cirrhotic rats. The rats of the second group (n = 27) were administered carbon tetrachloride (CCl4) by intraperitoneal injection to induce liver cirrhosis. The cirrhotic rats were then divided into three equal subgroups, each comprising nine animals, as follows: (i) cirrhotic rats, (ii) cirrhotic rats treated with camel milk, and (iii) cirrhotic rats treated with camel milk and bee honey. The present findings revealed that CCl4 elevated the activities of liver enzymes, blood glucose levels, non-esterified fatty acids (NEFA) in the serum and glycogen content in the liver. On the other hand, CCl4 significantly decreased phosphorylase activity in the liver tissue and significantly increased carbohydrate intolerance and insulin resistance index (HOMA-IR). Moreover, CCl4 induced a significant increase in oxidative stress, along with increased expression of the profibrotic cytokine genes TNF-α and TGF-β. However, camel milk either alone or in combination with bee honey ameliorated these toxic actions. The antioxidant properties of these protective agents and their effects of downregulating certain procirrhotic cytokine gene transcripts underlie this protection.

Dietary Vitamin E Supplementation Attenuates Hypertension in Dahl Salt-Sensitive Rats

There is strong evidence that excess dietary salt (NaCl) is a major factor contributing to the development of hypertension. Salt-sensitive humans and rats develop hypertension even on a normal-salt diet. Salt sensitivity is associated with glucose intolerance and insulin resistance in both humans and animal models, including Dahl salt-sensitive (DSS) rats. In insulin resistance, impaired glucose metabolism leads to elevated endogenous aldehydes that bind sulfhydryl groups of membrane proteins, altering calcium channels, and increasing cytosolic free calcium ([Ca2+] i) and blood pressure. Vitamin E lowers tissue aldehyde conjugates, cytosolic [Ca2+] i, and blood pressure in spontaneously hypertensive rats and fructose-induced hypertensive Wistar Kyoto rats, models of insulin resistance. This study investigated the effect of a normal-salt diet on tissue aldehyde conjugates, cytosolic [Ca2+] i, and blood pressure in DSS rats and the effect of vitamin E supplementation on blood pressure and associated biochemical changes in these animals. Seven-week-old DSS rats were divided into 3 groups of 6 animals each and treated for 6 weeks with diets as follows: low-salt (0.4% NaCl); normal-salt (0.7% NaCl) and normal salt (0.7% NaCl) plus vitamin E (34 mg/kg feed). At completion, animals in the normal-salt group had significantly elevated systolic blood pressure, cytosolic [Ca2+] i, and tissue aldehyde conjugates compared with the low-salt group. They also showed smooth muscle cell hyperplasia in small arteries and arterioles of the kidney. Dietary vitamin E supplementation significantly attenuated the increase in systolic blood pressure and associated biochemical and histopathologic changes.

The Role of Calcium in Ameliorating the Oxidative Stress of Fluoride in Rats

The present study was carried out to investigate the effects of fluoride toxicity on some biochemical, hormonal, and histological parameters of female rats and the protective role of calcium against such effects. Adult female albino rats were divided into five groups; control group received distilled water for 60 days, calcium group received calcium carbonate with dose of 50 mg/kg three times per week for 60 days, fluoride group received sodium fluoride with dose of 20 mg/kg three times per week for 60 days, calcium + fluoride group received calcium carbonate (50 mg/kg) then after 2 h received sodium fluoride (20 mg/kg) three times per week for 60 days, and fluoride + calcium group received sodium fluoride (20 mg/kg) three times per week for 30 days then received calcium carbonate (50 mg/kg) three times per week for another 30 days. The results showed that the levels of thiobarbituric acid reactive substances, urea, creatinine, alkaline phosphatase, triiodothyronine, thyroxine, parathormone, phosphorous, magnesium, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and gamma glutamyl transferase were significantly increased in rats treated with fluoride while serum estradiol, calcium, and organ glutathione were significantly decreased. The histological examination of the femur bone revealed that fluoride treatment induced thinning of bone trabeculae with wilding of marrow space, demineralization, and loss of trabeculae interconnections. Also, the histological examination of hepatic and renal tissues of fluoride-treated rats showed some damages in these tissues while administration of calcium carbonate for 30 or 60 days during fluoride treatment minimized such damages. It could be concluded that administration of calcium to female rats can ameliorate the hazardous effects of fluoride observed in the biochemical, hormonal, and histological parameters.

Effect of the omega-3 fatty acid plus vitamin E supplementation on subjective global assessment score, glucose metabolism, and lipid concentrations in chronic hemodialysis patients

SCOPE

This study was conducted to determine the effects of omega-3 fatty acid plus vitamin E supplementation on subjective global assessment (SGA) score and metabolic profiles in chronic hemodialysis (HD) patients.

METHODS AND RESULTS

This randomized double-blind placebo-controlled clinical trial was conducted among 120 chronic HD patients. Participants were randomly divided into four groups to receive: (i) 1250 mg/day omega-3 fatty acid containing 600 mg eicosapentaenoic acid and 300 mg docosahexaenoic acid + vitamin E placebo (n = 30), (ii) 400 IU/day vitamin E + omega-3 fatty acids placebo (n = 30), (iii) 1250 mg omega-3 fatty acids/day + 400 IU/day vitamin E (n = 30), and (iv) omega-3 fatty acids placebo + vitamin E placebo (n = 30) for 12 wk. Fasting blood samples were taken at baseline and after 12-wk intervention to measure metabolic profiles. Patients who received combined omega-3 fatty acids and vitamin E supplements compared with vitamin E, omega-3 fatty acids, and placebo had significantly decreased SGA score (p < 0.001), fasting plasma glucose (p = 0.01), serum insulin levels (p = 0.001), homeostasis model of assessment insulin resistance (p = 0.002), and improved quantitative insulin sensitivity check index (p = 0.006).

CONCLUSION

Omega-3 fatty acids plus vitamin E supplementation for 12 wk among HD patients had beneficial effects on SGA score and metabolic profiles.

Comparative hepatoprotective effects of tocotrienol analogs against drug-induced liver injury

Oxidative stress plays a major part in the pathogenesis of drug-induced liver injury. Yet, overcoming it with other xenobiotics impose additional risks. In this study, we consider the use of natural-occurring and purified Vitamin E analogs as hepatoprotective agents. Vitamin E is well-known for its intrinsic antioxidant property even though the differential effect of specific analogs of tocopherol (TP) and tocotrienol (T3) is still not ascertained. This study investigates the protective effect of T3 analogs (α-, δ-, γ−) in comparison with α-TP followed by assessing the underlying mechanisms of the cytoprotective T3 analog(s) in two xenobiotics-induced liver injury models using (1) acetaminophen (APAP)- and (2) hydrogen peroxide (H₂O₂). Both α-TP and α-T3 exerted cytoprotective effects while only lower concentration of γ-T3 was effective in inhibiting both toxicants induced injury. α-TP/α-T3 protected hepatocytes from APAP and H₂O₂-induced liver injury through arresting free radicals and inhibiting oxidative stress (inhibition of reactive oxygen species, lipid peroxidation and mitochondrial permeability transition). There was also demonstrable inhibition of the apoptotic pathway (inhibition of caspse-3 activity and overexpression of Bcl-_XL), accompanied with an induction of liver regeneration (PCNA and NF-kB). The cellular uptake of α-T3 was higher than α-TP at the same treatment dosage after 24 h. Overall, α-T3 seems to be a more potent hepatoprotective analog among the tocotrienols and α-TP at the same in vitro treatment dosage. In summary, these results suggest that α-TP/α-T3 elicit hepatoprotective effects against toxicants-induced damage mainly through activation of antioxidant responses at an early stage to prevent the exacerbation of injury.

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Purified T3 analogs were compared for their hepatoprotective effects against two toxicants-induced liver injuries.

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α-TP/α-T3 and lower concentration of γ-T3 exerted significant cytoprotective effects.

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α-TP/α-T3 inhibits oxidative stress and apoptosis while induces liver regeneration.

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α-T3 is the most potent hepatoprotective analog among T3 and α-TP at same dose.

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α-TP/α-T3 prevented toxicants-induced injury mainly through antioxidant responses.

Camel milk beneficial effects on treating gentamicin induced alterations in rats

The potential effect of camel milk (CM) against gentamicin (GM) induced biochemical changes in the rat serum was evaluated. Four groups of six albino rats were used for control, CM fed, injected with GM(i.p.), and then fed and injected with GM. The results showed that the administration of GM significantly altered the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) activity in rat serum. CM restored these parameters to almost their normal range in group IV. Additionally, the present study showed that injection of rats with gentamicin caused an increase in malondialdehyde (MDA) and myeloperoxidase (MPO) activity while the antioxidant enzymes like superoxide dismutase (SOD) and glutathione s-transferase (GST) activity decreased significantly (P ≤ 0.05). Administration of CM significantly (P ≤ 0.05) inhibited the formation of MDA and activity of MPO and upregulated the antioxidant enzymes (SOD and GST) activity. The overall findings of this study demonstrated that pretreatment with CM gave protection against GM induced hepatic damage possibly by inhibiting oxidative stress and inflammation, and hence camel milk can be identified as a new therapeutic agent.

Camel milk ameliorates steatohepatitis, insulin resistance and lipid peroxidation in experimental non-alcoholic fatty liver disease

Background

Camel milk (CM) is gaining increasing recognition due to its beneficial effects in the control and prevention of multiple health problems. The current study aimed to investigate the effects of CM on the hepatic biochemical and cellular alterations induced by a high-fat, cholesterol-rich diet (HCD), specifically, non-alcoholic fatty liver disease (NAFLD).

Methods

Seventy male Wistar rats were divided into four groups: the Control (C) Group fed a standard diet; the Control + camel milk (CCM) Group fed a standard diet and CM, the Cholesterol (Ch) Group fed a HCD with no CM, and the Cholesterol + camel milk (ChM) Group fed a HCD and CM. The following parameters were investigated in the studied groups; basal, weekly random and final fasting blood glucose levels, intraperitoneal glucose tolerance test (GTT) and insulin tolerance test (ITT), serum insulin, serum lipids, liver functions, lipid peroxidation products, the antioxidant activity of catalase (CAT) and the levels of reduced glutathione (GSH). In addition, HOMA-IR as an index of insulin resistance (IR) and the histopathology of the hepatic tissue were assessed.

Results

The Ch Group developed features similar to those of non-alcoholic steatohepatitis (NASH), characterized by hepatic steatosis; inflammatory cellular infiltration in liver tissue; altered liver functions; and increased total cholesterol, triglycerides, low-density lipoprotein cholesterol, very-low-density lipoprotein cholesterol, atherogenic index (AI), blood glucose, IR, and malondialdehyde (MDA) levels. Additionally, feeding the HCD to animals in the Ch Group decreased CAT activity and the GSH and high-density lipoprotein (HDL) cholesterol levels. Camel milk intake for eight weeks decreased hepatic fat accumulation and inflammatory cellular infiltration, preserved liver function, increased the GSH levels and CAT activity, decreased the MDA levels, and ameliorated the changes in the lipid profile, AI, and IR in animals from the ChM Group.

Conclusions

CM has a unique composition that is rich in minerals; vitamins, insulin and insulin-like protein, and it increased HDL-cholesterol and ameliorated the biochemical and cellular features of NAFLD in rats that received a HCD. The antioxidant effect of CM is a likely mechanism for the altered metabolism and absorption of HCD in the presence of CM. Regular consumption of CM could provide a natural way to protect against NAFLD induced by a high-fat diet.

Interaction of antioxidants and exercise on insulin sensitivity in healthy and prediabetic rats

Meal-induced insulin sensitization (MIS) describes the augmented postprandial response to insulin through action of the hepatic insulin sensitizing substance (HISS). HISS-action is impaired in insulin resistance associated with aging and type 2 diabetes, but could be preserved by the antioxidant cocktail SAMEC, along with voluntary exercise. In this study, we tested whether antioxidant supplementation during voluntary training would interact with the effects of exercise on HISS-mediated glucose uptake in healthy and prediabetic rats. The 7-day voluntary running-wheel training was used as an exercise intervention. SAMEC supplementation was provided only during the 7-day training session. The rapid insulin sensitivity test (RIST) was conducted to determine insulin- and HISS-dependent glucose uptake in 14-week-old healthy rats, and sucrose-induced insulin-resistant rats, with or without exercise in the presence or absence of SAMEC supplementation. The postprandial insulin sensitivity was increased by exercise, primarily through enhancement of the HISS-dependent glucose uptake, which remained unaffected by SAMEC. SAMEC supplementation did not either harm or add benefit to the positive effects of exercise on insulin sensitivity in healthy or prediabetic rats. While SAMEC alone was a demonstrated preventive against the progressive loss of HISS action in previous studies, short-term supplementation in this study did not reverse the established disease state.

Astaxanthin prevents loss of insulin signaling and improves glucose metabolism in liver of insulin resistant mice

This study investigates the effects of astaxanthin (ASX) on insulin signaling and glucose metabolism in the liver of mice fed a high fat and high fructose diet (HFFD). Adult male Mus musculus mice of body mass 25–30 g were fed either normal chow or the HFFD. After 15 days, mice in each group were subdivided among 2 smaller groups and treated with ASX (2 mg·(kg body mass)–1) in olive oil for 45 days. At the end of 60 days, HFFD-fed mice displayed insulin resistance while ASX-treated HFFD animals showed marked improvement in insulin sensitivity parameters. ASX treatment normalized the activities of hexokinase, pyruvate kinase, glucose-6-phosphatase, fructose-1,6-bisphosphatase, glycogen phosphorylase, and increased glycogen reserves in the liver. Liver tissue from ASX-treated HFFD-fed animals showed increased tyrosine phosphorylation and decreased serine phosphorylation of insulin receptor substrates (IRS)-1 and -2. ASX increased IRS 1/2 and phosphatidylinositol 3-kinase (PI3K) association and serine phosphorylation of Akt. In addition, ASX decreased HFFD-induced serine kinases (c-jun N-terminal kinase-1 and extracellular signal-regulated kinase-1). The results suggest that ASX treatment promotes the IRS–PI3K–Akt pathway of insulin signaling by decreasing serine phosphorylation of IRS proteins, and improves glucose metabolism by modulating metabolic enzymes.

A combination of ascorbic acid and α-tocopherol or a combination of Mg and Zn are both able to reduce the adverse effects of lindane-poisoning on rat brain and liver

The purpose of this study, carried out on male Wistar rats, was to evaluate the beneficial effects of supplementation with ascorbic acid (Vit C) and α-tocopherol (Vit E) or with Mg and Zn upon lindane-induced damages in liver and brain. Under our experimental conditions, lindane poisoning (5mg/kg body weight per day for 3 days) resulted in (1) an increased level of plasma glucose, cholesterol and triglycerides, (2) an increased activity of LDH, ALP, AST, ALT, (3) an oxidative stress in liver and brain as revealed by an increased level of lipids peroxidation (TBARS) and a decrease of glutathione-peroxidase, superoxide dismutase and catalase activities in liver and brain. In conclusion, both Vit C+E or Mg+Zn treatments display beneficial effects upon oxidative stress induced by lindane treatment in liver and brain.

Interactions of commonly used dietary supplements with cardiovascular drugs: a systematic review

BACKGROUND

The objective of this systematic review was to examine the benefits, harms and pharmacokinetic interactions arising from the co-administration of commonly used dietary supplements with cardiovascular drugs. Many patients on cardiovascular drugs take dietary supplements for presumed benefits and may be at risk for adverse supplement-drug interactions.

METHODS

The Allied and Complementary Medicine Database, the Cochrane Library, EMBASE, International Bibliographic Information on Dietary Supplements and MEDLINE were searched from the inception of the review to October 2011. Grey literature was also reviewed.Two reviewers independently screened records to identify studies comparing a supplement plus cardiovascular drug(s) with the drug(s) alone. Reviewers extracted data using standardized forms, assessed the study risk of bias, graded the strength of evidence and reported applicability.

RESULTS

Evidence was obtained from 65 randomized clinical trials, 2 controlled clinical trials and 1 observational study. With only a few small studies available per supplement, evidence was insufficient for all predefined gradable clinical efficacy and harms outcomes, such as mortality and serious adverse events. One long-term pragmatic trial showed no benefit from co-administering vitamin E with aspirin on a composite cardiovascular outcome. Evidence for most intermediate outcomes was insufficient or of low strength, suggesting no effect. Incremental benefits were noted for triglyceridemia with omega-3 fatty acid added to statins; and there was an improvement in levels of high-density lipoprotein cholesterol with garlic supplementation when people also consumed nitrates

CONCLUSIONS

Evidence of low-strength indicates benefits of omega-3 fatty acids (plus statin, or calcium channel blockers and antiplatelets) and garlic (plus nitrates or warfarin) on triglycerides and HDL-C, respectively. Safety concerns, however, persist.

Molecular mechanisms of hypertension--reactive oxygen species and antioxidants: a basic science update for the clinician

Many factors have been implicated in the pathophysiology of hypertension such as upregulation of the renin-angiotensin-aldosterone system, activation of the sympathetic nervous system, perturbed G protein-coupled receptor signalling, inflammation, and altered T-cell function. Common to these processes is increased bioavailability of reactive oxygen species (ROS) (termed oxidative stress) due to excess ROS generation, decreased nitric oxide (NO) levels, and reduced antioxidant capacity in the cardiovascular, renal, and nervous systems. Although oxidative stress may not be the sole etiology of hypertension, it amplifies blood pressure elevation in the presence of other prohypertensive factors. In the cardiovascular system ROS play a physiological role in controlling endothelial function, vascular tone, and cardiac function, and a pathophysiological role in inflammation, hypertrophy, proliferation, apoptosis, migration, fibrosis, angiogenesis, and rarefaction, all of which are important processes contributing to endothelial dysfunction and cardiovascular remodelling in hypertension. A major source for cardiovascular ROS is a family of nonphagocytic nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (Nox1, Nox2, Nox4, and Nox5). Other sources include mitochondrial enzymes, xanthine oxidase, and uncoupled NO synthase (NOS). Although convincing data from animal studies support a causative role for oxidative stress in the pathogenesis of hypertension, there is still no solid evidence that oxidative stress causes hypertension in humans. However, biomarkers of excess ROS are increased in patients with hypertension and oxidative damage is important in the molecular mechanisms associated with cardiovascular and renal injury in hypertension. Although clinical trials failed to show beneficial antihypertensive effects of antioxidants, strategies that combat oxidative stress by targeting Noxs in an isoform-specific manner may have therapeutic potential.

Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases

BACKGROUND

Our systematic review has demonstrated that antioxidant supplements may increase mortality. We have now updated this review.

OBJECTIVES

To assess the beneficial and harmful effects of antioxidant supplements for prevention of mortality in adults.

SEARCH METHODS

We searched The Cochrane Library, MEDLINE, EMBASE, LILACS, the Science Citation Index Expanded, and Conference Proceedings Citation Index-Science to February 2011. We scanned bibliographies of relevant publications and asked pharmaceutical companies for additional trials.

SELECTION CRITERIA

We included all primary and secondary prevention randomised clinical trials on antioxidant supplements (beta-carotene, vitamin A, vitamin C, vitamin E, and selenium) versus placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Three authors extracted data. Random-effects and fixed-effect model meta-analyses were conducted. Risk of bias was considered in order to minimise the risk of systematic errors. Trial sequential analyses were conducted to minimise the risk of random errors. Random-effects model meta-regression analyses were performed to assess sources of intertrial heterogeneity.

MAIN RESULTS

Seventy-eight randomised trials with 296,707 participants were included. Fifty-six trials including 244,056 participants had low risk of bias. Twenty-six trials included 215,900 healthy participants. Fifty-two trials included 80,807 participants with various diseases in a stable phase. The mean age was 63 years (range 18 to 103 years). The mean proportion of women was 46%. Of the 78 trials, 46 used the parallel-group design, 30 the factorial design, and 2 the cross-over design. All antioxidants were administered orally, either alone or in combination with vitamins, minerals, or other interventions. The duration of supplementation varied from 28 days to 12 years (mean duration 3 years; median duration 2 years). Overall, the antioxidant supplements had no significant effect on mortality in a random-effects model meta-analysis (21,484 dead/183,749 (11.7%) versus 11,479 dead/112,958 (10.2%); 78 trials, relative risk (RR) 1.02, 95% confidence interval (CI) 0.98 to 1.05) but significantly increased mortality in a fixed-effect model (RR 1.03, 95% CI 1.01 to 1.05). Heterogeneity was low with an I(2)- of 12%. In meta-regression analysis, the risk of bias and type of antioxidant supplement were the only significant predictors of intertrial heterogeneity. Meta-regression analysis did not find a significant difference in the estimated intervention effect in the primary prevention and the secondary prevention trials. In the 56 trials with a low risk of bias, the antioxidant supplements significantly increased mortality (18,833 dead/146,320 (12.9%) versus 10,320 dead/97,736 (10.6%); RR 1.04, 95% CI 1.01 to 1.07). This effect was confirmed by trial sequential analysis. Excluding factorial trials with potential confounding showed that 38 trials with low risk of bias demonstrated a significant increase in mortality (2822 dead/26,903 (10.5%) versus 2473 dead/26,052 (9.5%); RR 1.10, 95% CI 1.05 to 1.15). In trials with low risk of bias, beta-carotene (13,202 dead/96,003 (13.8%) versus 8556 dead/77,003 (11.1%); 26 trials, RR 1.05, 95% CI 1.01 to 1.09) and vitamin E (11,689 dead/97,523 (12.0%) versus 7561 dead/73,721 (10.3%); 46 trials, RR 1.03, 95% CI 1.00 to 1.05) significantly increased mortality, whereas vitamin A (3444 dead/24,596 (14.0%) versus 2249 dead/16,548 (13.6%); 12 trials, RR 1.07, 95% CI 0.97 to 1.18), vitamin C (3637 dead/36,659 (9.9%) versus 2717 dead/29,283 (9.3%); 29 trials, RR 1.02, 95% CI 0.98 to 1.07), and selenium (2670 dead/39,779 (6.7%) versus 1468 dead/22,961 (6.4%); 17 trials, RR 0.97, 95% CI 0.91 to 1.03) did not significantly affect mortality. In univariate meta-regression analysis, the dose of vitamin A was significantly associated with increased mortality (RR 1.0006, 95% CI 1.0002 to 1.001, P = 0.002).

AUTHORS' CONCLUSIONS

We found no evidence to support antioxidant supplements for primary or secondary prevention. Beta-carotene and vitamin E seem to increase mortality, and so may higher doses of vitamin A. Antioxidant supplements need to be considered as medicinal products and should undergo sufficient evaluation before marketing.

Amelioration of glucose induced hemolysis of human erythrocytes by vitamin E

Cells under aerobic condition are always threatened with the insult of reactive oxygen species, which are efficiently taken care of by the highly powerful antioxidant systems of the cell. The erythrocytes (RBCs) are constantly exposed to oxygen and oxidative stress but their metabolic activity is capable of reversing the injury under normal conditions. In vitro hemolysis of RBCs induced by 5, 10 and 20mM glucose was used as a model to study the free radical induced damage of biological membranes in hyperglycemic conditions and the protection rendered by vitamin E on the same. RBCs are susceptible to oxidative damage, peroxidation of the membrane lipids, release of hemoglobin (hemolysis) and alteration in activity of antioxidant enzymes catalase and superoxide dismutase. The glucose induced oxidative stress and the protective effect of vitamin E on cellular membrane of human RBCs manifested as inhibition of membrane peroxidation and protein oxidation and restoration of activities of superoxide dismutase and catalase, was investigated. Thiobarbituric acid reactive substances are generated from decomposition of lipid peroxides and their determination gives a reliable estimate of the amount of lipid peroxides present in the membrane. Vitamin E at 18 μg/ml (normal serum level) strongly enhanced the RBC resistance to oxidative lysis leading to only 50-55% hemolysis in 24h, whereas RBCs treated with 10 and 20mM glucose without vitamin E leads to 70-80% hemolysis in 24h. Levels of enzymic antioxidants catalase, superoxide dismutase and nonenzymic antioxidants glutathione showed restoration to normal levels in presence of vitamin E. The study shows that vitamin E can protect the erythrocyte membrane exposed to hyperglycemic conditions and so a superior antioxidant status of a diabetic patient may be helpful in retarding the progressive tissue damage seen in chronic diabetic patients.

Evaluation of Oxidative Stress in Type 2 Diabetes Mellitus and Follow-up Along with Vitamin E Supplementation

Increased oxidative stress is a widely accepted participant in the development and progression of diabetes and its complications. The present study has been undertaken to evaluate oxidative stress in type 2 diabetes mellitus and effect of vitamin E supplementation on oxidative stress. In all 120 subjects were enrolled in the present study, 40 subjects are age and sex matched controls. Test group comprised of clinically diagnosed (n = 80) type 2 diabetic patients. Biochemical parameters like serum MDA, nitric oxide, superoxide dismutase, erythrocyte reduced glutathione and platelet aggregation were analyzed in control and diabetic group. Test group is further categorized as Group I (n = 40) diabetics were treated by only hypoglycemic drugs and Group II (n = 40) diabetics were treated by hypoglycemic drugs with vitamin E supplementation. All above biochemical parameters were again reassessed after 3 months follow-up in both group and its values were compared with its respective baseline levels. The study shows, reduction of oxidative stress, improvement in antioxidant enzymes and endothelial dysfunction in group II, those were on treatment of hypoglycemic drugs along with vitamin E supplementation. Hence the present study may conclude that vitamin E supplementation along with hypoglycemic drugs may be beneficial to type 2 DM patients to minimize vascular complications.

Potassium, Magnesium, and Electrolyte Imbalance and Complications in Disease Management

Electrolyte balance is a critical issue in managing comorbid conditions in both diseased and elderly patients. Patients with hypertension and diabetes need careful regulation of their calcium and magnesium levels, whereas in patients with congestive heart failure, sodium and potassium levels also are critical. Herein we report the outcome of a round table discussion at which issues of renal magnesium clearance, magnesium and arrhythmic risk, ion balance in heart failure, diabetes, ischemic stress, oxidative stress in the cardiomyopathy of magnesium deficiency, roles of magnesium and potassium in bone metabolism and the aging population, and the role of electrolyte balance in hypertension have been discussed. In all these issues the maintaining homeostasis of potassium and magnesium is critical and the various therapies that impact on retaining these ions were discussed. Hallmark studies, i.e., Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial and Studies of Left Ventricular Dysfunction, have provided insight into treatment of patients with cardiovascular and progressive heart failure. These studies and the availability of potassium- and magnesium-sparing diuretics for use in these disorders provide relevant perspectives for treatment.

Effects of antioxidant supplementation on insulin sensitivity, endothelial adhesion molecules, and oxidative stress in normal-weight and overweight young adults

The objective of the study was to determine whether short-term antioxidant (AOX) supplementation affects insulin sensitivity, endothelial adhesion molecule levels, and oxidative stress in overweight young adults. A randomized, double-blind, controlled study tested the effects of AOXs on measures of insulin sensitivity (homeostasis model assessment [HOMA]) and quantitative insulin sensitivity check index), endothelial adhesion molecules (soluble intercellular adhesion molecule-1, vascular adhesion molecule, and endothelial-leukocyte adhesion molecule-1), adiponectin, and oxidative stress (lipid hydroperoxides) in overweight and normal-weight individuals (N = 48, 18-30 years). Participants received either AOX (vitamin E, 800 IU; vitamin C, 500 mg; beta-carotene, 10 mg) or placebo for 8 weeks. The HOMA values were initially higher in the overweight subjects and were lowered with AOX by week 8 (15% reduction, P = .02). Adiponectin increased in both AOX groups. Soluble intercellular adhesion molecule-1 and endothelial-leukocyte adhesion molecule-1 decreased in overweight AOX-treated groups by 6% and 13%, respectively (P < .05). Plasma lipid hydroperoxides were reduced by 0.31 and 0.70 nmol/mL in the normal-weight and overweight AOX-treated groups, respectively, by week 8 (P < .05). Antioxidant supplementation moderately lowers HOMA and endothelial adhesion molecule levels in overweight young adults. A potential mechanism to explain this finding is the reduction in oxidative stress by AOX. Long-term studies are needed to determine whether AOXs are effective in suppressing diabetes or vascular activation over time.

Oxidative stress in prehypertension: rationale for antioxidant clinical trials

Prehypertension has been recently described as an independent category of blood pressure. Mounting evidence suggests that blood pressure in the prehypertensive range is associated with an increased risk of developing hypertension and cardiovascular disease. Several reports have assigned a critical role for oxidative stress in these disease processes. This review focuses on the clinical and experimental studies done in prehypertension and hypertension within the context of oxidative stress. This article also provides insights into why diverse therapeutic interventions, which have in common the ability to reduce oxidative stress, can impede or delay the onset of hypertension in prehypertension subjects.

Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases

BACKGROUND

Animal and physiological research as well as observational studies suggest that antioxidant supplements may improve survival.

OBJECTIVES

To assess the effect of antioxidant supplements on mortality in primary or secondary prevention randomised clinical trials.

SEARCH STRATEGY

We searched The Cochrane Library (Issue 3, 2005), MEDLINE (1966 to October 2005), EMBASE (1985 to October 2005), and the Science Citation Index Expanded (1945 to October 2005). We scanned bibliographies of relevant publications and wrote to pharmaceutical companies for additional trials.

SELECTION CRITERIA

We included all primary and secondary prevention randomised clinical trials on antioxidant supplements (beta-carotene, vitamin A, vitamin C, vitamin E, and selenium) versus placebo or no intervention. Included participants were either healthy (primary prevention trials) or had any disease (secondary prevention trials).

DATA COLLECTION AND ANALYSIS

Three authors extracted data. Trials with adequate randomisation, blinding, and follow-up were classified as having a low risk of bias. Random-effects and fixed-effect meta-analyses were performed. Random-effects meta-regression analyses were performed to assess sources of intertrial heterogeneity.

MAIN RESULTS

Sixty-seven randomised trials with 232,550 participants were included. Forty-seven trials including 180,938 participants had low risk of bias. Twenty-one trials included 164,439 healthy participants. Forty-six trials included 68111 participants with various diseases (gastrointestinal, cardiovascular, neurological, ocular, dermatological, rheumatoid, renal, endocrinological, or unspecified). Overall, the antioxidant supplements had no significant effect on mortality in a random-effects meta-analysis (relative risk [RR] 1.02, 95% confidence interval [CI] 0.99 to 1.06), but significantly increased mortality in a fixed-effect model (RR 1.04, 95% CI 1.02 to 1.06). In meta-regression analysis, the risk of bias and type of antioxidant supplement were the only significant predictors of intertrial heterogeneity. In the trials with a low risk of bias, the antioxidant supplements significantly increased mortality (RR 1.05, 95% CI 1.02 to 1.08). When the different antioxidants were assessed separately, analyses including trials with a low risk of bias and excluding selenium trials found significantly increased mortality by vitamin A (RR 1.16, 95% CI 1.10 to 1.24), beta-carotene (RR 1.07, 95% CI 1.02 to 1.11), and vitamin E (RR 1.04, 95% CI 1.01 to 1.07), but no significant detrimental effect of vitamin C (RR 1.06, 95% CI 0.94 to 1.20). Low-bias risk trials on selenium found no significant effect on mortality (RR 0.91, 95% CI 0.76 to 1.09).

AUTHORS' CONCLUSIONS

We found no evidence to support antioxidant supplements for primary or secondary prevention. Vitamin A, beta-carotene, and vitamin E may increase mortality. Future randomised trials could evaluate the potential effects of vitamin C and selenium for primary and secondary prevention. Such trials should be closely monitored for potential harmful effects. Antioxidant supplements need to be considered medicinal products and should undergo sufficient evaluation before marketing.

Efeitos do dimetilsulfóxido no estresse oxidativo e na regeneração hepática pós-hepatectomia em ratos

OBJETIVO: avaliar a influência do DMSO sobre o estresse oxidativo e a regeneração hepática pós-HP via um modelo experimental. MÉTODO: 36 ratos Wistar machos jovens foram aleatoriamente distribuídos em dois Grupos de 18 animais: parcialmente hepatectomizados com infusão diária de solução salina (controle) e parcialmente hepatectomizados com aporte diário intraperitoneal de DMSO, todos por duas semanas. Nos tempos 36h (T1), 168h (T2) e 336h (T3) pós-HP, glutationa (GSH) foi medida no plasma e no tecido hepático, enquanto glicose e bilirrubina total foram aquilatados no sangue. A massa do fígado residual, nos mesmos tempos, foi o parâmetro utilizado para estimar a evolução da regeneração do fígado. RESULTADOS: DMSO baixou os níveis de GSH hepático e sangüíneo mas não interferiu na evolução da massa em regeneração. CONCLUSÃO: DMSO inibiu o estresse oxidativo pós-HP mas não mostrou alterações significantes na regeneração hepática em ratos.

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.