The Relationship Between Vitamin D and Telomere/Telomerase: A Comprehensive Review.

Telomeres are repetitive nucleotide sequences that together with the associated sheltrin complex protect the ends of chromosomes and maintain genomic stability. Evidences from various organisms suggests that several factors influence telomere length regulation, such as telomere binding proteins, telomere capping proteins, telomerase, and DNA replication enzymes. Recent studies suggest that micronutrients, such as vitamin D, folate and vitamin B12, are involved in telomere biology and cellular aging. In particular, vitamin D is important for a range of vital cellular processes including cellular differentiation, proliferation and apoptosis. As a result of the multiple functions of vitamin D it has been speculated that vitamin D might play a role in telomere biology and genomic stability. In this study, our main goal is investigating the relationship between telomerase enzyme and vitamin D. Findings of this study suggest that higher vitamin D concentrations, which are easily modifiable through nutritional supplementation, are associated with longer LTL, which underscores the potentially beneficial effects of this hormone on aging and age-related diseases. Vitamin D may reduce telomere shortening through anti-inflammatory and anti-cell proliferation mechanisms. Significant Low levels of telomerase activity create short telomeres, which in turn signal exit from the cell cycle resulting in cell senescence and apoptosis. In follow-up examination, the patients who remained vitamin D deficient tended to have shorter telomeres than those patients whose 25-hydroxyvitamin D levels were depleted. Increasing 25-hydroxyvitamin D levels in patients with SLE may be beneficial in maintaining telomere length and preventing cellular aging. Moreover, anti-telomere antibody levels may be a promising biomarker of SLE status and disease activity.

Vitamin D increases IGF-I and insulin levels in experimental diabetic rats.

INTRODUCTION AND OBJECTIVE: Previous studies have found that IGF-I may play an important role in glucose metabolism. The aim of this study is to examine the effect of vitamin D intake on the serum levels of glucose, insulin, and IGF-I in experimental diabetic rats. MATERIAL AND METHODS: A total of 24 male Sprague-Dawley rats aged six to seven months, with an average weight of 300±30g, were randomly divided into three groups (eight rats per group). The first group served as control and the other two groups received an intraperitoneal injection of 45mg/kg streptozotocin (STZ) to develop diabetes. Then groups were treated for four weeks either with placebo or vitamin D (two injections of 20,000IU/kg). RESULTS: At the end of the experiment, two injection of vitamin D were found to result in a significant increase in plasma cholecalciferol, which could improve hyperglycaemia and hypoinsulinemia in diabetic rats. HbA1c concentration had a slight and insignificant decrease following vitamin D intake. In addition, a significant decline was observed in the serum IGF-I level of STZ-treated rats in comparison to the controls, which was compensated in the vitamin D group. The serum vitamin D concentration was positively correlated to the changes in IGF-I level by Pearson test. CONCLUSIONS: These data showed for the first time that vitamin D intake could significantly improve fasting plasma glucose, insulin, and IGF-I in an experimental type 1 diabetes model.

Effects of L-carnitine supplementation on biomarkers of oxidative stress, antioxidant capacity and lipid profile, in patients with pemphigus vulgaris: a randomized, double-blind, placebo-controlled trial.

BACKGROUND/OBJECTIVES: Pemphigus vulgaris (PV), as an autoimmune disease including mucosa and the skin, is associated with several complications and comorbidities. The present study planned to determine the effect of L-carnitine (LC) supplementation on biomarkers of oxidative stress (OS), antioxidant capacity and lipid profile in PV patients.Subjects/MethodsFifty two control and patients with PV, participated in the current randomized, double-blind, placebo-controlled clinical trial. The patients were allocated randomly to receive 2 g per day LC tartrate subdivided into two equal doses of 1 g before breakfast and dinner (n=26) or placebo (n=26) for 8 weeks. Anthropometric, lipid profile and OS values were determined at baseline and end of intervention period. RESULTS: LC intake significantly reduced serum levels of triglycerides, total-, LDL- cholesterol and oxidative stress index (OSI; P<0.05). In addition, supplementation with LC resulted to a meaningful increase in levels of total antioxidant capacity (TAC) (P=0.05) and serum carnitine (P<0.001). LC intake revealed non-significant change in serum total oxidant capacity (P=0.15) and HDL- cholesterol (P=0.06) in comparison to the placebo. CONCLUSIONS: LC consumption may have favorable results on TAC, OSI and lipid profiles in patients with PV. The results were in line with the idea that LC supplementation can be associated with positive effects on metabolic status and OS of patients with PV.European Journal of Clinical Nutrition advance online publication, 23 August 2017; doi:10.1038/ejcn.2017.131.

Beneficial effects of omega-3 and vitamin E coadministration on gene expression of SIRT1 and PGC1α and serum antioxidant enzymes in patients with coronary artery disease.

BACKGROUND AND AIM: SIRT1 and PGC1α are two important genes, which play critical roles in regulating oxidative stress and inflammation processes. The study aimed assess the effects of coadministration of omega-3 and vitamin E supplements on SIRT1 and PGC1α gene expression and serum levels of antioxidant enzymes in coronary artery disease (CAD) patients. METHODS AND RESULTS: Participants of this randomized controlled trial included 60 CAD male patients who were categorized into three groups: Group 1 received omega-3 (4 g/day) and vitamin E placebo (OP), group 2 omega-3 (4 g/day) and vitamin E (400 IU/day; OE), and group 3 omega-3 and vitamin E placebos (PP) for 2 months. Gene expression of SIRT1 and PGC1α in peripheral blood mononuclear cells (PBMCS) was assessed by reverse transcription polymerase chain reaction (RT-PCR). Furthermore, serum antioxidant enzyme and high-sensitivity C-reactive protein (hsCRP) levels were assessed at the beginning and end of the intervention. Gene expression of SIRT1 and PGC1α increased significantly in the OE group (P = 0.039 and P = 0.050, respectively). Catalase and hsCRP levels increased significantly in the OE and OP groups. However, glutathione peroxidase (GPX) and superoxide dismutase (SOD) levels did not statistically change in all groups. The total antioxidant capacity (TAC) increased significantly in the OE group (P = 0.009) but not in OP and PP groups. CONCLUSION: Supplementation of omega-3 fatty acids in combination with vitamin E may have beneficial effects on CAD patients by increasing gene expression of SIRT1 and PGC1α and improving oxidative stress and inflammation in these patients.

Effect of vitamins A, E, C and omega-3 fatty acids supplementation on the level of catalase and superoxide dismutase activities in streptozotocin-induced diabetic rats.

BACKGROUND: Since free radicals and antioxidant enzymes may play an important role in the development of diabetes, the present study was designed to assess the effect of supplementation with vitamins A, E and C and ω-3 fatty acids on catalase and superoxide dismutase activity in streptozotocin (STZ)-induced diabetic rats. METHODS: A total of 64 male Wistar rats weighing 250 g were divided into four groups as normal control, diabetic control, diabetic supplemented with vitamin A, E and C and diabetic supplemented with ω-3 fatty acids. After four weeks the rats were anesthetized and catalase (CAT) and superoxide dismutase (SOD) activities were investigated in blood samples, liver and heart homogenates. RESULTS: In diabetic rats, the activity levels of heart SOD (p < 0.001) and heart and liver CAT (p < 0.001) were significantly lower than in normal control rats. Supplementation with vitamins A, E and C significantly increased heart CAT (p = 0.05). No significant change was observed in diabetic rats supplemented with ω-3 fatty acids. CONCLUSION: Supplementation with vitamins A, E and C and ω-3 fatty acids was found to increase heart CAT activity in diabetic rats and they can be valuable candidates in the treatment of the complications of diabetes (Tab. 6, Ref. 26).

Evaluation of antioxidant enzyme activity and antioxidant capacity in patients with newly diagnosed pemphigus vulgaris.

BACKGROUND: Pemphigus vulgaris (PV) is an autoimmune blistering disorder of the skin and/or mucosa. Increased levels of reactive oxygen species (ROS) were previously reported in PV. AIM: Because oxidative stress has an important role in the inflammatory process, we designed this study to evaluate the antioxidant status in patients with PV and to compare it with that of healthy controls (HCs). METHODS: In this case-control study, 43 newly diagnosed patients with PV were compared with 58 HCs. The severity of the disease was estimated according to Harman scores. Erythrocyte glutathione peroxidase (GPx), superoxide dismutase (SOD), CAT and serum malondialdehyde (MDA) activities and total antioxidant capacity were measured. Data were analyzed by independent t-test. RESULTS: Both groups were similar in sex, age and body mass index. Mean duration of disease was 5.6 months. Mean oral and skin severities were 1.79 and 2.3 respectively, based on Harman scores. SOD activity was not significantly different between groups (1003.30 ± 39.96 vs. 1009.76 ± 32.68 U/gHb). Levels were noticeably higher in patients with PV than in HCs for both GPx (52.13 ± 2.85 vs. 36.63 ± 1.49 U/gHb, respectively; P < 0.001) and CAT (205.69 ± 8.10 vs. 130.26 ± 6.80 kU/gHb, respectively; P < 0.001) activities, and CAT activity correlated with disease severity. In addition, patients had lower total antioxidant capacity than controls (3.39 ± 0.06 vs. 3.72 ± 0.09 mmol/L, P = 0.006). There was no noticeable difference in serum MDA between the two groups (P = 0.45). CONCLUSIONS: Patients with PV have significantly higher antioxidant enzyme activities and lower total antioxidant capacity compared with HCs. These data indicate the importance of improving antioxidant level in patients with pemphigus.

Effect of diet-induced weight loss on inflammatory cytokines in obese women.

BACKGROUND: Obesity is associated with lowgrade systemic inflammation which has been linked to the increased risk of cardiovascular disease and Type 2 diabetes in obese patients. AIM: To evaluate changes in pro/anti-inflammatory adipocytokines and metabolic profile after moderate diet-induced weight loss. SUBJECTS AND METHODS: Twenty-nine pre-menopausal obese women (body mass index ≥30 kg/m2) aged 21 to 54 years without diabetes, hypertension, or hyperlipidemia, were enrolled in this study. We measured anthropometric parameters, lipid and glucose profiles, interleukin (IL)-6, IL-10, and IL-18 in obese women, who then entered a medically supervised program aimed at reducing body weight by 10% or more. Obese women restricted their caloric intake (by 500-1000 kcal/day) and consumed 50 g/day of a fiber supplement (Slim Last Powder) for 12 weeks. RESULTS: By completing the dietary intervention program, weight (Δ = -10.0%, p<0.0001), body mass index, waist circumference, triceps skinfold thickness, total cholesterol, triglyceride, and fasting plasma glucose significantly decreased, while HDL-cholesterol significantly increased. While plasma levels of IL-6 and IL-18 decreased by 27% after 12 weeks, no significant change was observed in circulating levels of IL-10. CONCLUSION: Our study suggests that an improved body composition induced by restriction of energy intake is associated with favorable serum concentrations of IL-6 and IL-18 in obese women. However, the anti-inflammatory IL-10 is not affected by a moderate weight decrease.