Therapeutic Hypothermia and Recombinant Erythropoietin Mitigate Brain Microvascular Endothelial Cell Dysfunction via Modulating the Pentose Phosphate Pathway.

Neonatal brains are particularly vulnerable to oxidative stress, making the pentose phosphate pathway (PPP) pivotal in damage limitation. This study aimed to confirm the mechanism of erythropoietin combined with therapeutic hypothermia (TH) in hypoxic-ischemic brain damage (HIBD). Neonatal HIBD rat models were employed and the impacts of erythropoietin and TH on behavior, cerebral infarction, pathology, and microvascular were evaluated. Following that, the assessments of inflammation, oxidative stress, apoptosis, and the level of glucose-6-phosphate dehydrogenase (G6PD, rate-limiting enzyme in the PPP) proceeded. Human brain microvascular endothelial cells (HBMECs) underwent oxygen-glucose deprivation (OGD) and were treated with TH and G6PD inhibitor RRx-001. The impacts of the G6PD inhibitor on HBMEC function and barrier were evaluated. Simultaneous administration of TH and EPO reduced pathological damage and attenuated microvascular loss. In addition, this combination therapy had anti-inflammatory, antioxidant, and anti-apoptotic properties, and enhanced G6PD activity, both in vivo and in vitro. Inhibition of G6PD disrupted the protective effects of TH and EPO on the patency of the PPP and the function of HBMECs, and barrier integrity was further broken. This study reveals that the combination of TH and EPO mitigates microvascular endothelial cell dysfunction via partially modulating the PPP, thus preserving barrier integrity.