The effect of ectopic fat on graft function after living kidney transplantation

Renal transplantation is associated with a large number of risk factors that can have an influence on early renal graft function (ERGF). One of these factors could be the increasing number of obese kidney donors. The mechanisms of reduced ERGF in obese kidney donors are still poorly understood. To that end, we compared ERGF in recipients with body mass index (BMI), perivascular fat and plasma inflammation markers of live kidney donors. We hypothesized that the BMI of donors would negatively correlate with an average increase of glomerular filtration rate (GFR) and that it would also be associated with increased perivascular and plasma inflammation markers in the first seven days after transplantation. Between January 2013 and December 2014, some 58 living kidney transplantation pairs were included in the study. Donor and recipient demographic data, preoperative BMI, blood C-reactive protein (CRP) and adiponectin levels, perivascular adipose tissue (PAT) samples and recipient blood creatinine levels were analyzed. The median CRP of donors was 0.68 mg/l (max: 8.66 mg/l, min: 0.33 mg/l), the median of M1 macrophages (CD14+CD16+) in one gram of PAT was 5940 (max: 41 100, min: 248) and the median of adiponectin was 411 930 pg/ml (max: 14 217 000, min: 167 300) in plasma. We did not find any association between early renal graft function and the percentage of M1 macrophages in donor perirenal adipose tissue (p=0.83, r=0.03, n=58), adiponectin (p=0.65, r=0.06, n=58) or CRP (p=0.16, r=0.2, n=58) in plasma. The obesity level of donors, expressed as BMI, did not correlate with early renal graft function in the first seven days after transplantation. The associations between ERGF and plasma and perivascular fat inflammation markers were not significant. We confirmed a negative correlation between the BMI of recipients and an average increase of GFR in the first seven days after transplantation (p<0.02, r=-0.325, N=58). We confirmed a negative correlation of adiponectin plasma concentration to the BMI of donors.