Association Between Coffee Consumption and Circulating Levels of Adiponectin and Leptin.

Coffee has been proposed to have benefits for chronic diseases; however, the relevant mechanism remains to be elucidated. We conducted a cross-sectional study and evaluated the levels of adiponectin and leptin in relation to coffee consumption. We included a total of 4406 individuals (men = 2587 and women = 1819) for adiponectin analysis and 2922 individuals (men = 1731 and women = 1191) for leptin analysis. Participants answered number of cups of coffee per week and types of coffee they consumed and their serum levels of adiponectin and leptin were measured using an enzyme-linked immunosorbent assay. We found that increasing coffee consumption was associated with increased levels of adiponectin among women; geometric means of adiponectin were 8.0 (95% CI: 7.2-8.9 µg/mL) among women who regularly consumed 15 or greater cups/week, but 7.5 (95% CI: 6.8-8.4 µg/mL) among women who did not consume coffee (P for trend = .009). Leptin levels were inversely associated with coffee consumption among both men and women (P for trend = .04 for men and 0.04 for women); geometric means of 15 or greater cups of coffee per week were 2.6 (95% CI: 2.4-2.8 ng/mL) among men and 5.1 (95% CI: 4.5-5.8 ng/mL) among women, but for noncoffee drinkers, geometric means were 3.0 (95% CI: 2.7-3.3 ng/mL) for men and 5.8 (95% CI: 5.1-6.6 ng/mL) for women. Coffee consumption was associated with higher circulating levels of adiponectin and lower circulating levels of leptin. Our study may suggest that improvement in adipocyte function contributes to the beneficial metabolic effects of coffee consumption.

The effect of lithospermic acid, an antioxidant, on development of diabetic retinopathy in spontaneously obese diabetic rats.

BACKGROUND: Lithospermic acid B (LAB), an active component isolated from Salvia miltiorrhiza radix, has been reported to have antioxidant effects. We examined the effects of LAB on the prevention of diabetic retinopathy in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, an animal model of type 2 diabetes. METHODS AND FINDINGS: LAB (10 or 20 mg/kg) or normal saline were given orally once daily to 24-week-old male OLETF rats for 52 weeks. At the end of treatment, fundoscopic findings, vascular endothelial growth factor (VEGF) expression in the eyeball, VEGF levels in the ocular fluid, and any structural abnormalities in the retina were assessed. Glucose metabolism, serum levels of high-sensitivity C-reactive protein (hsCRP), monocyte chemotactic protein-1 (MCP1), and tumor necrosis factor-alpha (TNFα) and urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels were also measured. Treatment with LAB prevented vascular leakage and basement membrane thickening in retinal capillaries in a dose-dependent manner. Insulin resistance and glucose intolerance were significantly improved by LAB treatment. The levels of serum hsCRP, MCP1, TNFα, and urinary 8-OHdG were lower in the LAB-treated OLETF rats than in the controls. CONCLUSIONS: Treatment with LAB had a preventive effect on the development of diabetic retinopathy in this animal model, probably because of its antioxidative effects and anti-inflammatory effects.