Valvular oxidized phospholipids correlate with severity of human aortic valvular stenosis

Calcific aortic valve stenosis (CAVS) is a degenerative disease characterized by progressive calcification and narrowing of the aortic valve, driven by a multifactorial inflammatory process. Oxidized phospholipids (OxPL) have been implicated in CAVS pathogenesis, but their presence within aortic valve tissue remains poorly defined. In this study, we developed a sensitive 2,4-dinitrophenylhydrazine (DNPH)-based LC/MS/MS method to identify and quantify 60 individual OxPL species across five phospholipid classes in plasma and tissue samples from patients with severe CAVS. Aortic valve tissue was collected from 70 patients undergoing valve replacement surgery and compared with tissue from 20 healthy donors. We identified 32 distinct OxPL species, including oxidized phosphatidylcholine (OxPC), phosphatidylethanolamine (OxPE), phosphatidylinositol (OxPI), and phosphatidylserine (OxPS). OxPC was the most abundant class, with 1-palmitoyl-2-(9-oxo-nonanoyl)-sn-glycero-3-phosphocholine (PONPC) being the predominant species, accounting for 35 % of total OxPL. We observed a significant increase in 30 OxPL species with advancing disease severity, with the most pronounced changes occurring between early (healthy and mild) and advanced (moderate and severe) stages of CAVS. Specifically, PONPC levels increased by 90 % (p = 0.012), and total OxPC levels rose by 83 % (p = 0.004) from mild to moderate disease. Compared to healthy valves, OxPC levels increased by 123 % (p < 0.0001) in moderate CAVS and by 239 % (p = 0.02) in severe CAVS. However, OxPL levels did not significantly increase between moderate and severe stages. These findings suggest that OxPL accumulation in valve tissue is an early event in CAVS progression, supporting the rationale for early intervention with OxPL-lowering therapies as a potential strategy to mitigate disease advancement.