Is microvascular flow rate related to ghrelin, leptin and adiponectin levels?

Ghrelin, leptin and adiponectin are three hormones which are frequently associated with metabolism, obesity and appetite. Recently, it has been shown that they may possess other physiologic roles, specially in connection with the circulation. Ghrelin infusion increases forearm blood-flow in a dose-dependent manner. Leptin has been shown to be involved not only in thermogenesis but angiogenesis as well. Adiponectin, apart from its insulin-sensitizing action, appears to modulate inflammation by inhibiting monocyte adhesion to endothelial cells. Six monkeys, which had been classified as being in the pre-diabetic state, where administered a triglyceride lowering regimen. Microvascular function was assessed using a laser Doppler flow-meter during a temperature provocation test. Percent change in flow from baseline following temperature elevation, as well as percent change in flow/degree rise in temperature were used to evaluate microvascular reserve and reactivity. Using univariate analysis, it appears that increased perfusion is significantly correlated with adiponectin, followed by leptin. Flow was also positively correlated with ghrelin, but the relationship did not attain significance. As expected, flow was also negatively and significantly correlated with fibrinogen. Trends show that flow was also negatively correlated to circulating triglyceride levels (p=0.08). The data indicate that the three hormones appear to possess microvascular actions that may impact on their other physiologic functions.