Metabolic plasma signatures in thoracic aortic aneurysm associated to tricuspid and bicuspid aortic valves

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto de Salud Carlos III with co-funding from the ERDF and Comunidad de Madrid

Thoracic aortic aneurysm (TAA) develops asymptomatic with life-threatening consequences and its diagnosis is usually fortuitous. TAA is mostly idiopathic, although its prevalence is significantly higher in subjects with bicuspid aortic valve (BAV) for unknown reasons. We hypothesize that it is essential to investigate idiopathic TAA by differentiating between BAV and tricuspid aortic valve (TAV) patients for personalized diagnosis and treatment.

We aimed to identify plasma metabolic profiles of aortic dilatation in idiopathic TAA, differentiating between subjects with BAV or TAV.

Plasma samples from 41 idiopathic TAA patients and 57 subjects without aortic dilatation (control, C) were collected and classified according to aortic valve type (BAV or TAV). Full metabolomics coverage was carried out by 1H RMN and LC-MS/MS untargeted analysis, including reverse phase and hydrophilic interaction chromatography and positive and negative electrospray ionization modes. Significant variation in metabolite levels were considered if FDR-adjusted p-value <0.05.

Our analyses highlighted a metabolic signature specific for BAV and TAV subjects. BAV patients presented a marked glycerophospholipid metabolism alteration involving different lysophospholipids (LPAs, LPCs and LPEs) and phospholipids (PCs, PEs, PAs and PIs). Particularly, LPCs and LPEs were increased in BAV-TAA vs BAV-C, being an indicator of stimulation of glucose utilization through glycolysis and suppression of fatty acid biosynthesis. In contrast, carnitine-related metabolism was the most altered pathway observed in TAV subjects. In particular, we detected an increment in plasma acylcarnitines in TAV-TAA compared to TAV-C suggesting an altered β-oxidation of fatty acids and mitochondrial overload.

Idiopathic TAA development is differentially reflected in plasma from BAV and TAV patients, supporting an individualized diagnosis valve-dependent and suggesting also differential therapeutic targets.