This article reports a case of an elderly male patient presenting with nephrotic syndrome. Renal biopsy pathology indicated membranous nephropathy, with both renal tissue staining for M-type phospholipase A2 receptor (PLA2R) and serum anti-PLA2R antibodies being negative. Nephrotic syndrome achieved remission following treatment with prednisone combined with tacrolimus; however, the patient relapsed during tacrolimus maintenance therapy. Subsequent laboratory evaluation revealed positive anti-nuclear antibodies and anti-double-stranded DNA antibodies, accompanied by decreased complement levels. Exostosin 1 and Exostosin 2 staining performed on the initial renal biopsy specimen yielded positive results, leading to a diagnosis of lupus nephritis. Due to the patient's history of rituximab-related allergic reactions, pulmonary infection, and acute kidney injury, the subsequent treatment regimen consisted of obinutuzumab sequentially combined with belimumab, in addition to prednisone 10 mg/d. During the two-year follow-up period, the patient's anti-double-stranded DNA antibodies converted to negative, complement levels normalized, proteinuria achieved complete remission, and no adverse events such as severe infection occurred. This article reviews the diagnosis, treatment, and relevant literature for this case, aiming to provide clinical insights for the early diagnosis and selection of therapeutic strategies for similar patients.

Acute kidney injury (AKI) is a heterogeneous clinical complication with no existing definite or particular therapies. Therefore, molecular mechanisms and approaches for treating acute kidney injury are in urgent need. Herein, we demonstrated that dexrazoxane (DXZ), a U.S. Food and Drug Administration (FDA)-approved cardioprotective drug, can both functionally and histologically attenuate cisplatin or ischemia-reperfusion injury-induced AKI in vitro and in vivo via inhibiting ferroptosis specifically. This effect is characterized by decreasing lipid peroxidation, shown by the biomarker of oxidative stress 4-hydroxynonenal (HNE) and prostaglandinendoperoxide synthase 2 (Ptgs2), while reversing the downregulation of glutathione peroxidase 4 (GPX4) and ferritin 1 (FTH-1). Mechanistically, the results revealed that DXZ targeted at the renal tubule significantly inhibits ferroptosis by suppressing α-amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD). Furthermore, the conjugation of dexrazoxane and polysialic acid (DXZ-PSA) is specifically designed and utilized to enhance the therapeutic effect of DXZ by long-term effect in the kidney, especially retention and targeting in the renal tubules. This study provides a novel therapeutic approach and mechanistic insight for AKI by inhibiting ferroptosis through a new type drug DXZ-PSA with the enhanced renal distribution.

Ferroptosis plays a critical pathophysiological role in several types of acute kidney injury (AKI). The development of nanomaterials targeting iron metabolism and ferroptosis is a promising approach for AKI treatment. Herein, we synthesized gallic acid-gallium polyvinyl pyrrolidone nanoparticles (GGP NPs) as a potential iron-scavenging agent because of their nearly ionic radius and chemical similarity with iron. The results indicated that GGP NPs accumulated in tubular epithelial cells and showed good biocompatibility. GGP NPs significantly inhibited cisplatin (CP)-induced ferroptosis in HK-2 cells by reducing the accumulation of intracellular free iron and mitochondrial dysfunction, and suppressing the perturbations of ferroptosis processes, including lipid peroxidation, nicotinamide adenine dinucleotide phosphate (NADPH) and glutathione (GSH) levels, glutathione peroxidase 4 (GPX4) activity, and ferritinophagy. An in vivo study demonstrated that treatment with GGP NPs significantly ameliorated the renal tubular injury and mitochondrial damage induced by CP treatment or ischemia-reperfusion injury. Our study suggests that GGP NPs may be an effective and promising candidate for AKI treatment and enable potential clinical translation.