1) We are continuing our work on exosomes as a source of biomarkers, including methods to improve recovery of exosomal proteins and miRNA. 2) We have also entered into a public-private consortium with the HESI Genomics microRNA Focus Group to compare standard protocol vs site-specific protocols from multiple sites; variations will identify which preanalytical steps affect microRNA detection and quantification in biofluids in drug-induced injury models. The initial model is a cardiotoxin that stimulates release of miRNAs into the circulation, which will shed light on renal handling of miRNA. Urinary miRNA from non-renal sources is expected to be non-exosomal. 3) We continue to work on alternatives to serum creatinine as surrogates for glomuerular filtration rate, such as serum cystatin C.