Decreased flow-mediated dilation in healthy Chinese adolescent with a family history of type 2 diabetes.

BACKGROUND: Endothelial dysfunction appears early in the development of cardiovascular disease and is associated with type 2 diabetes. We, therefore, tested the hypothesis that endothelial dysfunction is already present in healthy Chinese adolescent participants at risk of type 2 diabetes and associates with physical activity. METHODS: We investigated the flow-mediated dilation in 65 first-degree relatives (normal tension, normal glucose tolerance) and 62 age-, sex- and BMI-matched controls without a family history of type 2 diabetes by ultrasound. Physical activity level was assessed using the Global Physical Activity Questionaire and type 2 diabetes family history through self-reporting. The association between physical activity and flow-mediated dilation was evaluated by Pearson correlations and multiple regressions in adolescents with or without a family history of type 2 diabetes. RESULTS: Female adolescents display better flow-mediated dilation than males. Adolescents with a family history of type 2 diabetes had significantly impaired flow-mediated dilation than healthy controls. Among the parameter detection in the blood, the flow-mediated dilation is only positively associated with high-density lipoprotein cholesterol level, but not others. Interestingly, flow-mediated dilation is positively corrected with physical activity scores in both the male and female adolescents, while slightly impaired but not significant in adolescents with a family history of type 2 diabetes. CONCLUSION: Studies in adolescents are important to understand the early pathogenesis of type 2 diabetes. Findings of this investigation suggest that family history of type 2 diabetes may play a role in regulating the vascular function in Chinese adolescents. Given the impaired flow-mediated dilation in individuals with family history and the effects of physical activity in improved flow-mediated dilation, people with a family history of type 2 diabetes may need higher physical activity levels to attenuate their susceptibility to impaired flow-mediated dilation.

Orexin A prevents degradation of the articular matrixes in human primary chondrocyte culture.

Excessive production of pro-inflammatory cytokines such as interleukin-1ß (IL-1ß) plays a key role in the pathophysiological development of osteoarthritis (OA). Orexin A is an important peptide of hypothalamic origin, which has displayed its multiple biological functions in several chronic diseases via activation of its specific G-protein coupled receptors, orexin-1 receptor (OX1R) and orexin-2 receptor (OX2R). In this study, we aimed to characterize the protective effects of orexin A against IL-1ß-induced degradation of articular cartilage matrixes in human chondrocytes. Our results indicate that OX1R but not OX2R was expressed in human chondrocytes. We also found that the expression of OX1R was significantly lower in chondrocytes from OA patients, and that treatment with IL-1ß decreased the expression of OX1R in a dose-dependent manner. The presence of orexin A ameliorated IL-1ß-induced degradation of type II collagen and aggrecan, the two major components of articular cartilage matrixes. Our results also show that orexin A prevented IL-1ß-induced expression of catabolic enzymes such as MMP-3, MMP-13, ADAMTS-4, and ADAMTS-5. Mechanistically, orexin A treatment abolished activation of the transcriptional factor NF-κB via inhibition of KKα/IκB-α phosphorylation and IκB-α degradation. These findings suggest that orexin A might act as an effective therapeutic agent for the treatment of OA.