Regenerative Versus Nonregenerative Repair of the Renal Medulla After Reversal of Ureteral Obstruction

The study examines the repair mechanisms of the renal medulla after reversing unilateral ureteral obstruction (R-UUO) in mice, revealing that while the medulla's size and architecture are restored 3 months post-reversal, functional defects persist due to cellular disorganization. The research highlights strain and sex-based differences in repair outcomes, with female BALB/c mice faring better than males. Despite histological recovery, persistent defects in cellular organization impair urinary concentrating capacity. The study suggests that regenerative repair is crucial to minimize long-term functional defects, as maladaptive repair features, such as vascular rarefaction and fibrosis, contribute to sustained medullary hypoxia. Understanding these mechanisms could inform therapeutic strategies for renal recovery post-obstruction.