Strategic timing of contralateral nephrectomy after ischemic AKI prevents CKD by enhancing epithelial progenitor proliferation while attenuating polyploidization

Kidneys have a limited ability to self-repair, and their response to injury not seldomly leads to chronic kidney disease (CKD). An intriguing phenomenon of successful recovery is observed in models of unilateral acute kidney injury (AKI) upon contralateral nephrectomy. Here we aimed to better understand the cellular mechanisms of this enhanced reparative effect.In a time-course study with different nephrectomy delay times, we found that the most effective rescue after injury was observed when contralateral nephrectomy was performed early during AKI in both rats and mice. This timely intervention led to full functional recovery and attenuation of tubular atrophy, fibrosis, and inflammation, averting AKI-to-CKD transition. Morphometry of histopathology using pathomics revealed distinct trajectories of structural alterations of kidney tubules, distinguishing between atrophy and repair, as adaptive signatures. These responses were corroborated by transcriptomics analysis, which indicated improved cellular energy metabolism after nephrectomy. Lineage tracing of tubular progenitor cells showed that nephrectomy robustly stimulated their clonal expansion, surpassing the levels observed during spontaneous self-repair. Live cell cycle/DNA-content analysis of tubular cells demonstrated a robust polyploid response immediately after the ischemic insult, and revealed that nephrectomy attenuated long term tubular cell polyploidization, a contributor to CKD. Altogether, our data revealed that early timing of nephrectomy in experimental AKI induces an efficient repair response, involving tubular epithelial regeneration while counteracting the progression towards CKD.