Metabolic reprogramming in sepsis-associated acute kidney injury: insights from lipopolysaccharide-induced oxidative stress and amino acid dysregulation.

Background: Sepsis-associated acute kidney injury (SA-AKI) stands out as a critical health issue due to its high mortality and morbidity rates. This study aimed to comprehensively investigate the biochemical and metabolic alterations induced by lipopolysaccharide (LPS) in human embryonic kidney cells (HEK-293) using an in vitro model.

Methods and results: The study investigated the impact of LPS on HEK-293 cells by evaluating cytotoxicity using the MTT assay, analyzing apoptosis, cell cycle progression, and oxidative stress via flow cytometry, measuring TNF-α levels through ELISA, and assessing amino acid metabolism with LC-MS/MS. The findings demonstrated that LPS significantly reduced cell viability in a dose-dependent manner, increased apoptotic cell populations, induced DNA damage by arresting the cell cycle in the Sub-G1 phase, and activated oxidative stress pathways. Notably, elevated reactive oxygen species (ROS) production and increased secretion of the pro-inflammatory cytokine TNF-α highlighted LPS's inflammatory and cytotoxic effects. Furthermore, systematic analysis revealed LPS-induced disruptions in amino acid metabolism, including marked reductions in alanine, arginine, and aspartic acid levels. KEGG pathway analysis identified significant metabolic alterations in pathways such as the urea cycle, TCA cycle, and glutathione metabolism. Interestingly, elevated citrulline levels suggested a potential adaptive mechanism to counteract LPS-induced inflammation and oxidative stress. Additionally, ROC analysis identified cystine as a highly reliable biomarker, with an AUC value of 1.00, emphasizing its critical role in metabolic reprogramming associated with SA-AKI.

Conclusions: This study provides critical insights into the molecular pathophysiology of SA-AKI and emphasizes the promise of metabolomic approaches in the early diagnosis of sepsis-related complications and the development of targeted therapies.