L -Ergothioneine Attenuates Nephrolithiasis by Modulating Redox Signaling and Mitochondrial Function in Cystine and Calcium Oxalate Models

AIMS: Nephrolithiasis is a major global health challenge, with oxidative stress and mitochondrial dysfunction emerging as key drivers of renal injury and stone formation. l-ergothioneine (l-Erg), a naturally occurring antioxidant transported by OCTN1, has shown promising effects in cystinuria models, preventing stone formation. Despite evidence supporting an indirect mechanism of action, key mechanistic aspects have yet to be fully clarified. This study aimed to evaluate whether l-Erg can prevent stone progression in cystinuria and in other types of lithiasis, such as calcium oxalate nephrolithiasis, and to further elucidate its mechanistic basis. RESULTS: Using mouse models, l-Erg significantly reduced cystine stone growth and renal inflammation, and its combination with d-penicillamine enhanced stone dissolution and mitigated drug-related toxicity. In calcium oxalate nephrolithiasis, l-Erg decreased crystal deposition, preserved renal architecture, normalized glutathione levels, and restored mitochondrial respiration. Transcriptomic analysis revealed downregulation of immune pathways and activation of cell cycle genes, suggesting attenuation of inflammation and promotion of tubular repair. INNOVATION: This study is the first to demonstrate that l-Erg exerts renoprotective effects through combined antioxidant and mitochondrial mechanisms in two major forms of nephrolithiasis and introduces a dual therapeutic approach combining an antioxidant with a cystine-solubilizing agent. CONCLUSION: 44, 878-891.