Mesangial expansion at 5 years predicts death and death-censored graft loss after renal transplantation.

Abstract

Death with a functioning graft and death-censored renal allograft failure remain major problems for which effective preventative protocols are lacking. The retrospective cohort study aimed to determine whether histologic changes on a 5-year surveillance kidney biopsy predict adverse outcomes after transplantation in recipients who had: both Type 2 diabetes (T2DM) and obesity (BMI≥30kg/m2 ) at the time of transplantation (T2DM/Obesity, n=75); neither (No T2DM/No obesity, n=78); No T2DM/Obesity (n=41), and T2DM/No obesity (n=47). On 5-year biopsies, moderate-to-severe mesangial expansion was more common in the T2DM/Obesity group (Banff mm score ≥2=49.3%; Tervaert classification MS≥2b=26.7%) compared to the other groups (p<.001 for both scores). Risk factors included older age, higher BMI, HbA1C, and triglycerides at 1-year post-transplant. Moderate-to-severe mesangial expansion correlated with death with function (HR 1.74 (1.01, 2.98), p=.045 Banff and 1.89 (1.01, 3.51) p=.045 Tervaert) and with death-censored graft loss (HR 3.2 (1.2, 8.8), p=.02 Banff and HR 3.8 (1.3, 11.5), p=.01 Tervaert) over a mean of 11.6years of recipient follow-up post-transplant. These data suggest that mesangial expansion in recipients with T2DM and obesity may reflect systemic vascular injury and might be a novel biomarker to predict adverse outcomes post renal transplant.