Vitamin B12 Protects the Exacerbated Ischemia–Reperfusion Injury-Induced Chronic Kidney Disease in Mice with Genetically Increased Elmo1

Ischemia-reperfusion injury (IRI) is a leading cause of acute kidney injury (AKI) and a major driver of progression to chronic kidney disease (CKD). Oxidative stress is recognized as a central mediator of this transition. Engulfment and Cell Motility 1 (ELMO1) regulates cytoskeletal remodeling and reactive oxygen species generation through Rac1 activation, but its contribution to CKD progression remains poorly defined. To investigate this, we established a unilateral renal IRI model in wild-type (WT) and <i>Elmo1</i>-overexpressing (<i>Elmo1^H/H</i>) mice and evaluated kidney function one and four months post-IRI. Compared with WT, <i>Elmo1^H/H</i> mice developed more severe kidney dysfunction, including an elevated plasma cystatin C and urinary albumin-to-creatinine ratio, reduced estimated glomerular filtration rate (eGFR), and pronounced fibrosis and glomerular injury observed by light and electron microscopy. Molecular analysis confirmed the dysregulation of redox-related pathways by RT-qPCR, with RNA sequencing showing enrichment of oxidative stress signatures. A subset of mice received chronic vitamin B12 (B12) supplementation following IRI to evaluate its therapeutic potential. Vitamin B12 supplementation improved kidney function, reduced fibrosis, preserved glomerular structure, and normalized the expression of antioxidant genes in both groups. These findings identify <i>Elmo1</i> as a driver of redox-mediated kidney injury and support vitamin B12 as a promising antioxidant therapy for AKI-to-CKD progression.