Melatonin supplementation and pro-inflammatory mediators: a systematic review and meta-analysis of clinical trials.

BACKGROUND: Inflammatory processes are involved in chronic diseases. It has been suggested that melatonin reduces inflammation by its radical scavenging properties; however, the results of the previous studies are inconclusive. The objective of the present meta-analysis is to determine the direction and magnitude of melatonin supplementation effect on inflammatory biomarkers. METHODS: Databases including PubMed, Scopus, Cochran Library, Embase, and Google Scholar were searched up to April 2019. Meta-analysis was performed using random-effect model. Subgroup analysis, sensitivity analysis, and meta-regression were also carried out. RESULTS: Thirteen eligible studies with 22 datasets with total sample size of 749 participants were included in the meta-analysis. Melatonin supplementation significantly decreased TNF-α and IL-6 levels [(WMD = - 2.24 pg/ml; 95% CI - 3.45, - 1.03; P < 0.001; I2 = 96.7%, Pheterogeneity < 0.001) and (WMD = - 30.25 pg/ml; 95% CI - 41.45, - 19.06; P < 0.001, I2 = 99.0%; Pheterogeneity < 0.001)], respectively. The effect of melatonin on CRP levels was marginal (WMD = - 0.45 mg/L; 95% CI - 0.94, 0.03; P = 0.06; I2 = 96.6%, Pheterogeneity < 0.001). CONCLUSION: The results of the present meta-analysis support that melatonin supplementation could be effective on ameliorating of inflammatory mediators.

The Risk of Developing Obesity, Insulin Resistance, and Metabolic Syndrome in Former Power-sports Athletes - Does Sports Career Termination Increase the Risk.

INTRODUCTION: Obesity is associated with several complications like metabolic syndrome. Many professional athletes adopt a sedentary lifestyle after retirement. This study was aimed at assessing the risk of developing obesity, insulin resistance (IR), and metabolic syndrome among former power-sports athletes, compared with age-matched active athletes and nonathletes. MATERIALS AND METHODS: The study was conducted in Mashhad during 2012-2014. The individuals were recruited through announcements and were divided into three groups of active athletes (n = 34), ex-athletes (n = 30), and nonathletes (n = 30). Demographic and anthropometric data were collected and biochemical factors including low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol, triglycerides (TG), fasting plasma glucose, insulin, and high-sensitive C-reactive protein were measured. RESULTS: Ex-athletes had significantly higher mean values of weight, body mass index, diastolic blood pressure, LDL-C, insulin, homeostatic model assessment (HOMA) IR, and HOMA ß-cell function (HOMA-%ß-cell) compared with active athletes and nonathletes (P < 0.001, P < 0.001, P < 0.001, P = 0.03, P = 0.01, P = 0.02, and P = 0.01, respectively). However, mean values of HDL-C was significantly lower in ex-athletes compared with nonathletes (P < 0.001). The prevalence of metabolic syndrome showed no significant difference among three groups, although its mean was higher among ex-athletes. CONCLUSIONS: The results showed that abandoning regular athletic exercise and weight cycling in power sports athletes leads to adverse outcomes such as obesity and IR. Although higher IR might not necessarily result in metabolic syndrome in short term, it could cause metabolic syndrome in the long run.

17ß-estradiol improves the efficacy of exploited autologous bone marrow-derived mesenchymal stem cells in non-union radial defect healing: A rabbit model.

Exploiting mesenchymal stem cells (MSCs) appears to be an appealing alternative to the traditional clinical approach in the treatment of non-union bone defects. It has been shown that 17ß-estradiol improves the osteogenesis and proliferation potential of the MSCs via estrogen receptors. We investigated the effect of 17ß-estradiol on exploiting autologous BMSCs (bone marrow-derived MSCs) for the purpose of healing of radial non-union segmental defect in rabbit. Twenty rabbits were divided into 4 experimental groups: 1. Control group; 2. MSC treatment group; 3. 17ß-estradiol (E2) treatment group; and 4. E2+MSC treatment group. Isolated BMSCs were seeded in a critical-sized defect on radial mid-diaphysis that was filled with autologous fibrin clot differently in 4 groups: 1. intact fibrin clot (control); 2. Fibrin clot containing MSCs; 3. Estradiol; and 4. E2 and MSCs. Defect healing was assessed by radiological (week 0, 2, 4, 6, 8 and 10) and histopathological evaluation (week 10). Radiological evaluation data demonstrated that quantities for the E2+MSC group were significantly the greatest in comparison with the other groups at week 4 to 10 inclusive. Moreover, Histopathological evaluation indicated that the E2+MSC group had the highest score which was significantly greater than the E2 group and the control group (P<0.05). In-vivo application of in situ 17ß-estradiol provides the seeded BMSCs with improved osteogenic capacity in tandem with an accelerated rate of bone healing. This obviously more qualified approach that yields in a shorter time appears to be promising for the future cell-based clinical treatments of the non-union bone fractures. Exploiting mesenchymal stem cells (MSCs) appears to be an appealing alternative to the traditional clinical approach in the treatment of non-union bone defects. It has been shown that 17ß-estradiol improves the osteogenesis and proliferation potential of the MSCs via estrogen receptors. We investigated the effect of 17ß-estradiol on exploiting autologous BMSCs (bone marrow-derived MSCs) for the purpose of healing of radial non-union segmental defect in rabbit. Twenty rabbits were divided into 4 experimental groups: 1. Control group; 2. MSC treatment group; 3. 17ß-estradiol (E2) treatment group; and 4. E2+MSC treatment group. Isolated BMSCs were seeded in a critical-sized defect on the radial mid-diaphysis that was filled with autologous fibrin clot differently in 4 groups: 1. intact fibrin clot (control); 2. Fibrin clot containing MSCs; 3. Estradiol; and 4. E2 and MSCs. Defect healing was assessed by radiological (week 0, 2, 4, 6, 8 and 10) and histopathological evaluation (week 10). Radiological evaluation data demonstrated that quantities for the E2+MSC group were significantly the greatest in comparison with the other groups at week 4 to 10 inclusive. Moreover, Histopathological evaluation indicated that the E2+MSC group had the highest score which was significantly greater than the E2 group and the control group (P<0.05). In-vivo application of in situ 17ß-estradiol provides the seeded BMSCs with improved osteogenic capacity in tandem with an accelerated rate of bone healing. This obviously more efficient approach that yields in a shorter time appears to be promising for future cell-based clinical treatments of the non-union bone fractures.