Adiponectin is unrelated to kidney function or injury markers in renal transplant recipients: A one-year follow-up study.

ABSTRACT

BACKGROUND: Adiponectin (ADPN) is a biologically active cytokine produced by adipose tissue. This protein exhibits anti-inflammatory, antioxidant, antifibrotic, and insulin-sensitizing properties. As ADPN is primarily eliminated by the kidneys, it is a potential biomarker of chronic kidney disease progression. This study aimed to analyze the fluctuations in ADPN levels after kidney transplantation during a one-year follow-up and to compare them to significant renal (eGFR, NGAL) and metabolic (insulin, glucose, lipids, HOMA-IR) markers. METHODS: Insulin, ADPN, NGAL, and basic biochemical parameters were evaluated in 51 healthy controls and 39 patients right before kidney transplantation and at five time points following transplantation (5-7 days, one month, three months, six months, and twelve months). RESULTS: Mean ADPN levels dropped significantly right after transplantation (from 35.449 to 30.920 µg/mL, p = 0.001) and decreased gradually over a year. From the third month after the transplantation, ADPN levels were comparable to healthy individuals. At the pre-transplant time point, ADPN correlated only with insulin (r = -0.60, p < 0.001) and HOMA-IR (r = -0.55, p < 0.001). At the timepoints after transplantation, ADPN correlated only with NGAL at three months (r = -0.70, p = 0.048). The correlation of ADPN with HOMA-IR found at pre-transplant was not significant at any post-transplant time point, but at one and three months after transplant, the correlations reached a borderline significance (p = 0.07 and p = 0.08, respectively). CONCLUSIONS: Successful kidney transplantation is followed by a gradual and significant ADPN decrease. In pre- and post-transplant patients, ADPN is unrelated to kidney function defined by GFR, but to glucose metabolism. Most of the analyzed metabolic and kidney parameters, apart from NGAL, stabilize within three months after transplantation.