MicroRNAs 1915-3p, 2861, and 4532 Are Associated with Long-Term Renal Function Decline in Type 1 Diabetes.

To the Editor: Diabetic kidney disease (DKD)1 is the leading cause of end-stage renal disease worldwide (1). Microalbuminuria is the earliest indicator of DKD in diabetes mellitus (DM). Microalbuminuria is clinically sensitive but not specific to this disease, which in some patients progresses with rapid glomerular filtration rate (GFR) decline (2). Research on new urinary biomarkers had demonstrated the ability of microRNAs (miRNAs) to discriminate between individuals with DKD and either healthy or non-DKD individuals (3). In an article published in Clinical Chemistry , Cardenas-Gonzalez et al. identified miRNAs miR-1915-3p, miR-2861, and miR-4532 as novel urinary miRNA biomarkers in DKD (3). Despite validating the results in different DM cohorts, the study's cross-sectional design was unable to address causality or prediction of subsequent outcomes. To further evaluate the prognostic potential of these new biomarkers, we tested the correlation between the expression of the 3 miRNAs and long-term estimated GFR (eGFR) decline in a cohort of 113 individuals with type 1 diabetes (T1D) who were recruited from 2013 to 2017 at the Diabetes Outpatient Clinic, Hospital das Clinicas. At the time of recruitment, spot urine samples were collected in sterile RNase-free flasks, centrifuged for 10 min, 3000 g at 4 °C, and frozen at −80 °C without additives or protease inhibitors within 4 h from collection. Clinical and demographic data [sex, age, T1D duration, use of angiotensin-converting …