Metabolic Stress and Adaptation in Pancreatic β-Cells to Hypoxia: Mechanisms, Modulators, and Implications for Transplantation.

Pancreatic β-cells are metabolically active endocrine cells with a high oxygen demand to sustain glucose-stimulated insulin secretion (GSIS). Hypoxia, arising from vascular disruption, islet isolation, or pathological states such as type 2 diabetes (T2D) and obstructive sleep apnoea (OSA), is a potent metabolic stressor that impairs β-cell function, survival, and differentiation. At the molecular level, hypoxia-inducible factors (HIF-1α and HIF-2α) orchestrate transcriptional programs that shift β-cell metabolism from oxidative phosphorylation to glycolysis, modulate mitochondrial function, and regulate survival pathways such as autophagy and mitophagy. Crosstalk with nutrient-sensing mechanisms, redox regulation, growth factor signaling, and protein synthesis control further shapes adaptive or maladaptive outcomes. Hypoxia alters glucose, lipid, and amino acid metabolism, while mitochondrial dysfunction, oxidative stress, and inflammatory signaling contribute to progressive β-cell failure. Therapeutic strategies including incretin hormones, GABAergic signaling, erythropoietin, ChREBP inhibition, and activation of calcineurin-NFAT or oxygen-binding globins-offer potential to preserve β-cell viability under hypoxia. In islet transplantation, oxygen delivery technologies, ischemic preconditioning, mesenchymal stem cell-derived exosomes, and encapsulation systems show promise in mitigating hypoxic injury and improving graft survival. This review synthesizes current knowledge on β-cell responses to hypoxic stress, with emphasis on metabolic reprogramming, molecular signaling, and translational interventions, underscoring that targeted modulation of β-cell metabolism and oxygen handling can enhance resilience to hypoxia and improve outcomes in diabetes therapy and islet transplantation.