Serum Adiponectin Levels and Ambulatory Blood Pressure Monitoring in Pediatric Renal Transplant Recipients

Background. Reduced levels of serum adiponectin, an adipokine, are associated with cardiovascular and obesity-related diseases; however, relations between adiponectin and hypertension are unclear. Methods. This cross-sectional study examined adiponectin and ambulatory blood pressure monitoring (ABPM) in 33 pediatric renal transplant recipients (TXP), aged 8 to 19 years, median of 1.9 years after transplant. Serum total adiponectin (mu g/mL) and high molecular weight-to-total adiponectin ratio (HMWr), 24-hr ABPM, and dual x-ray absorptiometry measures of fat mass were obtained. Results. The 12 TXP with hypertension (defined as BP index > 1.0 and BP load >25%) had lower total adiponectin levels (7.4 +/- 3.2 vs. 10.9 +/- 5.2 mu g/mL, P=0.045) compared with nonhypertensive TXP. Hypertensive TXP trended toward lower HMWr compared with nonhypertensive TXP (0.40 +/- 0.09 vs. 0.47 +/- 0.11, P=0.064). Levels did not differ according to sex, obesity or dipper status. In univariate analyses, total adiponectin and HMWr were negatively and significantly correlated with indexed BP in the daytime, nighttime, and 24-hr periods (R=-0.35 to -0.57). After adjustment for estimated glomerular filtration rate, fat mass, anti-hypertensive medication and fasting glucose, (1) lower total adiponectin was significantly and independently associated with greater elevations in all ABPM indexes except for nighttime systolic indexed BP, and (2) HMWr was inversely associated with all ABPM indexes. Lower adiponectin levels (P=0.049) and HMWr (P=0.042) were associated with greater odds of hypertension. Conclusion. These data indicate that lower total adiponectin and HMWr were significantly and independently associated with greater ambulatory blood pressure.