AKI-to-CKD transition is a potential mechanism for non-albuminuric diabetic kidney disease
Kyung Lee, John Cijiang He
Abstract
Although albuminuria development is considered the natural course of diabetic kidney disease (DKD), increasing evidence indicate that the disease can present as non-albuminuric DKD (NA-DKD), characterized by prominent tubulointerstitial injury and fibrosis without obvious glomerulopathy. However, the pathogenic mechanisms underlying NA-DKD remain unclear. As diabetic patients are more susceptible to acute kidney injury (AKI), and the maladaptive repair of kidney tubules following AKI occurs more frequently in diabetic than non-diabetic patients, the enhanced AKI-to-CKD transition may be a significant contributor of NA-DKD. Recent studies indicate that endoplasmic reticulum (ER) stress is a key pathogenic driver of AKI-to-CKD transition, and that the tubular expression of ER-resident protein reticulon 1A (RTN1A) correlates with human DKD progression and AKI-to-CKD transition. Experimental studies showed that RTN1A indeed mediates tubular cell injury and AKI-to-CKD transition in diabetic mice via concomitant activation of ER stress and mitochondrial dysfunction as a mediator of ER-mitochondrial crosstalk. Further understanding of the pathogenesis of tubular injury in DKD will help us to develop sensitive and specific biomarkers or diagnostic tools to distinguish between injury-related AKI, pre-renal AKI from hemodynamic changes, and the progression of DKD in order to better manage patients with DKD.