Adiponectin removal by the human kidney: A preliminary study

Background and aims: The adipocyte-derived adiponectin (APN) has potent insulin-sensitizing and anti-inflammatory properties. The adipose tissue is known to be the main source for APN in the circulation, but sites and mechanisms which remove APN from blood are still unknown in humans. Methods and results: We reviewed APN data obtained in previous studies in which the inter-organ exchange of amino acids and cytokines was measured in our laboratory. Results for kidney and splanchnic arterio-venous differences of APN were available for 5 subjects (age 57 ± 7 years, mean eGFR 79 ± 4 ml/min 1.73 m2). Both the liver and renal vein concentrations of total APN were lower than in the artery (by ∼32 and 20 %, respectively p < 0.05) indicating removal from blood; a similar trend (liver and renal vein level lower than the arterial by ∼22 and 15 %, respectively, p = NS) was observed for high molecular weight (HMW) APN. Conclusions: The present study identifies the splanchnic organs and the kidney as major sites for APN removal from blood in humans. Our data provide new understanding of kidney APN metabolism and suggests that reduced handling by the human kidney is a major factor to increase circulating APN in renal disease.