2-Hydroxyl hispolon reverses high glucose-induced endothelial progenitor cell dysfunction through the PI3K/Akt/eNOS and AMPK/HO-1 pathways

Background and Purpose: In diabetes (DM), elevated blood sugar levels contribute to the overproduction of reactive oxygen species (ROS), leading to endothelial progenitor cell (EPC) dysfunction. This study aimed to determine the potential of 2-hydroxy hispolon (2HH), a derivative of hispolon, to reverse high glucose-induced EPC dysfunction. Experimental Approach: Under in vitro high-glucose (HG) conditions, we investigated the effects of 2HH on three types of angiogenic cells: outgrowth endothelial cells (OECs), circulating angiogenic cells (CACs) and endothelial cells (ECs). In vivo, high-fat diet and streptozotocin-induced diabetic mice with hindlimb ischaemia were used to evaluate the effects of 2HH on angiogenesis and CAC mobilisation. Key Results: Treatment with 2HH significantly improved the proliferation, migration, tube formation, NO synthesis and ROS reduction in EPCs (OECs and CACs) under HG conditions by activating the AMP-activated protein kinase (AMPK)/haem oxygenase-1 (HO-1) and phosphoinositide 3-kinase (PI3K)/Akt/endothelial NOS (eNOS) signalling pathways but failed to restore EC dysfunction. In the in vivo hindlimb ischaemia model, 2HH administration in DM mice enhanced blood flow recovery in ischaemic hindlimbs, improved limb salvageability, increased the number of circulating CACs and increased capillary density in the ischaemic muscle. Furthermore, 2HH activated the AMPK/HO-1 and PI3K/Akt/eNOS pathways in CACs and ischaemic muscles. Conclusion and Implications: 2HH treatment effectively reduced oxidative stress and increased NO synthesis, thereby preventing HG-induced EPC dysfunction, primarily through the PI3K/Akt/eNOS and AMPK/HO-1 pathways. These findings offer a promising therapeutic avenue for attenuating susceptibility to critical limb ischaemia in patients with DM.