Elevation of serum adiponectin in mildly decreased glomerular filtration rate

Abstract

Background: Adiponectin secreted by adipocytes plays a key role in insulin sensitivity, anti-inflammation, and antiatherosclerosis. It is involved in several conditions including obesity, type 2 diabetes mellitus, cardiovascular disease, and chronic kidney disease (CKD). Glomerular filtration rate is monitored to indicate the kidney function and CKD progression. Objective: To assess the serum adiponectin levels in individuals with normal and mildly decreased glomerular filtration rate, analyze the association of serum adiponectin with various physical and biological parameters, and test whether serum adiponectin is the risk factor of mildly decreased glomerular filtration rate. Methods: This cross-sectional study was conducted in 172 individuals with 35-60 years of age. Serum samples were collected and divided into two groups, based on estimated glomerular filtration rate (eGFR): 90 with normal eGFR (G1, eGFR ≥90 mL/min/1.73 m 2 ) and 82 with mildly decreased eGFR (G2, eGFR = 60-89 mL/min/1.73 m 2 ). Anthropometric data were recorded. Serum adiponectin was measured by enzyme-linked immunosorbent assay. Results: Serum adiponectin levels were significantly increased in individuals with mildly decreased eGFR (G2), compared to G1 (8.23 ± 3.26 mg/mL and 6.57 ± 3.24 mg/mL, respectively; P = 0.001). Serum adiponectin was positively associated with age and high-density lipoprotein cholesterol but negatively associated with weight, body mass index, triglyceride, and waist and hip circumferences. Univariate analysis showed that serum adiponectin was significantly correlated with mildly decreased eGFR; however, when adjusting for confounding factors, there were no correlations. Furthermore, multivariate regression analysis showed that individuals at the age of 46-55 years (4.0; 95% CI: 1.9-8.3) and > 55 years (11.4; 95% CI: 3.7-35.5) were significantly correlated with mildly decreased eGFR. Conclusions: Serum adiponectin was significantly elevated in individuals with mildly decreased eGFR and may be a modulation factor, but was not an independent risk factor for mildly kidney damage. Further study is needed to clarify its potential benefits as monitoring biomarker for CKD progression.