Diabetes impacts >500 million people worldwide and increases the risk of cardiovascular disease, the leading cause of death globally. Mechanisms driving cardiovascular disease in diabetes are unique. Notably, we have shown that ferroptosis, an iron-dependent lipid-mediated form of cell death, has a central role in diabetic heart failure. Hypertension often precedes and contributes to diabetic heart failure, and blood pressure (BP) positively correlates with chronic hyperglycemia. However, the role of ferroptosis in hyperglycemia-associated BP elevation is unclear. Chronic hyperglycemia promotes oxidative stress, which can uncouple endothelial nitric oxide synthase (eNOS), shifting it from vasodilatory nitric oxide (NO) production to reactive oxygen species (ROS) generation. NO loss can contribute to hypertension and excess ROS can propagate lipid peroxidation and ferroptosis, exacerbating eNOS uncoupling in a vicious cycle. We hypothesized that hyperglycemia during diabetes activates ferroptosis, promoting eNOS dysregulation and increasing blood pressure. To test this hypothesis, we combined human population and in vitro mechanistic studies. Using the National Health and Nutrition Examination Survey (NHANES) 2021-2023 database, we tested associations between HbA1c, serum iron metabolism markers, and BP via causal mediation analyses (n=1,168). To mimic the diabetic milieu, HUV-EC-C endothelial cells were cultured for 4 days in 25 mM glucose, 1 μM insulin, and 150 μM palmitic acid (n=4). Mitochondrial ROS, malondialdehyde (MDA) release, and GPX4/GSR levels were measured. To determine hyperglycemia-driven eNOS dysregulation, HUV-EC-Cs were cultured in 5 mM or 25 mM glucose or 25 mM glucose with 100 nM angiotensin II, with and without 10 μM ferrostatin, a ferroptosis inhibitor, for 3 days (n=3). Angiotensin II was a positive control for non-compensated ROS-driven eNOS uncoupling via NADPH oxidase. In NHANES analyses, HbA1c positively correlated with serum ferritin (β=0.10, p=0.003) and transferrin (β=0.06, p=0.01). Ferritin mediated the association between HbA1c and systolic (natural indirect effect (NIE) β=0.16, p=0.04) and diastolic BP (NIE β=0.19, p=0.02). Transferrin mediated the relationship with diastolic BP (NIE β=-0.23, p=0.01). Total effects (TE) of HbA1c on BP were significant for systolic (TE β=3.73, p< 0.001) and diastolic BP (TE β=1.65, p=0.03). In vitro, the diabetic milieu increased mitochondrial ROS (p=0.04) and reduced GPX4 (p=0.03), indicating ferroptosis. High glucose increased eNOS (p=0.02), consistent with compensatory upregulation during uncoupling, which ferrostatin decreased (p=0.1). High glucose with angiotensin II did not alter eNOS levels and was unchanged by ferrostatin. To our knowledge, this is the first study to define iron metabolism as a mediator of hyperglycemia-associated hypertension, strengthened by robust causal mediation analysis of human data and complementary in vitro studies. Our findings suggest diabetes increases endothelial ferroptosis, contributing to eNOS dysregulation and hypertension. Ferroptosis may represent a mechanistic link between diabetes and hypertension and a potential therapeutic target to mitigate early cardiovascular dysfunction. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Freel et al. (Fri,) studied this question.