Interferon-activated neutrophils characterize coronary microvascular dysfunction in women with ANOCA

Background | Coronary microvascular dysfunction (CMD) is a common cause of ischemic symptoms in patients with angina and non-obstructive coronary arteries (ANOCA), predominantly women. Neutrophils may contribute to CMD via vascular inflammation and endothelial injury. We therefore investigated neutrophils and coronary endothelial cells in women with ANOCA. Methods | In this cross-sectional study, we collected blood samples from ANOCA patients (n=123, 84% women) undergoing coronary function testing. Complete blood counts (CELL-DYN, n=123) and neutrophil activation (AQUIOS, n=76) were assessed. Isolated neutrophils were profiled using single-cell RNA-seq (n=11). Guidewire-derived coronary endothelial cells (n=7) isolated during coronary function testing were cultured to passage 2 for bulk RNA-seq. Results | Of 103 women with ANOCA, 23 (22%) were diagnosed with CMD (CFR<2.5). These women showed higher NT-proBNP than women without CMD (234 [136-416] pg/ml vs. 112 [79-200] pg/ml, p<0.001). Neutrophil counts, neutrophil-to-lymphocyte ratio and systemic immune-inflammation index were higher among women with a lower coronary flow reserve (CFR). The proportion of activated neutrophils (CD62Ldim) was inversely associated with CFR at baseline. Single-cell RNA-seq identified four neutrophil clusters, including interferon (IFN)-activated and immature neutrophils. The IFN-activated cluster was expanded in patients with lower CFR and its proportion was inversely associated with surface CD62L expression. Immature neutrophils showed reduced translational and increased inflammatory gene expression in patients with low CFR. Coronary endothelial cells from patients with increased CD62Ldim neutrophils showed higher proliferative/metabolic and lower IFN, complement and coagulation pathway activity. Conclusion | Reduced CFR in women with ANOCA is associated with neutrophil activation, expansion of an IFN-activated neutrophil population, and altered immature neutrophil transcriptional programs. Neutrophil activation is accompanied by distinct endothelial signatures. These findings implicate neutrophil?endothelial interactions in CMD and identify IFN-associated neutrophil states as targets for mechanistic investigation.