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.