Early Prediction of Chronic Allograft Nephropathy by Non Invasive Monitoring of Urinary Cell mRNAs

mRNA profiling of urinary cells is fast evolving as a non-invasive substitute for invasive biopsy procedures employed for predicting renal allograft outcomes. This technique has been successfully used to develop biomarkers of acute rejection, but has not been evaluated for the diagnosis of allograft fibrosis.

The progressive scarring process of an allograft, called chronic allograft nephropathy (CAN), remains the chief cause of kidney transplant failure. We have shown by immunohistochemistry that epithelial changes suggestive of epithelial-to-mesenchymal transition (EMT) in early protocol biopsies predict the progression of CAN during the first year post-transplantation. Our preliminary results suggest that the urinary cell mRNA profile is altered in kidney transplant recipients (KTRs) with CAN.

The purpose of this study is to evaluate urine from KTRs during the first year post-transplantation to assess whether mRNA levels of genes involved in EMT/fibrogenesis can diagnose and predict CAN, and identify patients at risk of chronic allograft dysfunction.

The scientific underpinnings for our hypotheses are provided by (a) data showing that urinary cell mRNAs predict pathological changes (i.e., acute rejection) in renal allografts; and (b) our previous studies suggesting that CAN is characterized by altered urinary cell mRNA levels.

Our specific aims are to (1) investigate whether the levels of 21 mRNAs encoding genes involved in EMT/fibrogenesis and the alloimmune response are a sensitive and specific non-invasive diagnostic test for CAN in renal allografts; (2) determine whether mRNA profiles of sequential urine specimens can predict the development of CAN during the first year post-transplantation; and (3) determine whether mRNA profiles of sequential urine specimens predict the subsequent development of graft dysfunction as assessed by estimated GFR at 12, 24 and 36 months after transplantation.