Obesity-aggravated erythrocyte injury in ischaemia-reperfusion: Interlinked oxidative stress, metabolic reprogramming, and cytoskeletal destabilisation

Anaemia in obese patients who underwent major vascular surgery is closely associated with ischaemia-reperfusion injury (IRI)-driven erythrocyte damage and haemolysis. However, the obesity-specific mechanisms remain unknown. We investigated the interplay among oxidative stress, metabolic reprogramming, and cytoskeletal destabilisation in red blood cells (RBCs) during aortic IRI under obese conditions. Using a high-fat diet-induced obese mouse model subjected to abdominal aortic clamping–reperfusion, we systematically dissected the hierarchical mechanisms linking obesity to erythrocyte vulnerability during IRI. The key findings were—oxidative amplification—obese mice exhibited a pronounced intraerythrocytic reactive oxygen species surge post-IRI, accompanied by a compensatory upregulation of antioxidant enzymes (catalase and glutathione peroxidase). However, persistent accumulation of oxidative stress markers (malondialdehyde, 8-hydroxy-2′-deoxyguanosine, and carbonylated proteins) indicated overwhelming oxidative stress. Metabolic iron dysregulation—elevated Fe³⁺ and methaemoglobin levels and NADPH/ATP depletion indicated concurrent iron homeostasis disruption and metabolic crisis, respectively. RBCs glycolytic reprogramming is characterized by imbalanced glycolytic flux with accumulation of intermediates (glucose-6-phosphate [G6P] and fructose-6-phosphate), despite compensatory activation of the pentose phosphate pathway (PPP) and Rapoport-Luebering shunt (RLS). Structural destabilisation: critical cytoskeletal protein expression including expression of Band 3, glycophorin C, α/β-spectrin, and adducin, was significantly downregulated, with tropomodulin 1 and tropomyosin displaying the most prominent reductions, resulting in membrane fragility and haemolysis (elevated levels of haemoglobin, bilirubin, and circulating methaemoglobin). Collectively, we identified an ‘oxidative–metabolic–structural collapse’ axis that mediates obesity-aggravated erythrocyte injury during IRI, providing a mechanistic foundation for developing perioperative erythrocyte-protective strategies in metabolic syndrome with potential to improve cardiovascular surgery outcomes.