Proteomics profiling reveals signaling pathways associated with major adverse cardiovascular events in patients with hypertrophic cardiomyopathy

Abstract Background Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy affecting 1 in 200–500 people in the US. It is characterized by a diverse clinical course, and only a subset of patients with HCM experience major adverse cardiovascular events (MACE) such as arrhythmias (e.g., ventricular tachycardia/fibrillation [VT/VF], atrial fibrillation [AF]), stroke, and heart failure. However, the molecular mechanisms underlying the presence of MACE in HCM are still not well understood. Purpose Our aim was to reveal signaling pathways associated with prior MACE in patients with HCM by applying plasma proteomics profiling. Methods We conducted a multicenter case-control study of patients with HCM comparing those with and without a prior history of MACE. We performed plasma proteomics profiling of 5032 proteins. We defined prior MACE as a composite outcome of sustained VT/VF, AF, stroke/transient ischemic attack, left ventricular ejection fraction ≤50%, New York Heart Association functional class ≥2 symptoms, resuscitated cardiac arrest, or appropriate implantable cardioverter defibrillator therapy. We applied the random forest method to derive a proteomics-based discrimination model developed in patients enrolled at one institution (training set) and externally validated the model on patients enrolled at another institution (test set). We then performed pathway analysis of proteins differentially regulated in patients with prior MACE. Pathways with a false discovery rate (FDR) <0.05 with at least 5 associated proteins were declared positive. Results A total of 396 patients were included, with 278 in the training set and 118 in the test set. In this cohort, 251 (63%) patients had prior MACE (171 in the training set and 80 in the test set). Using the proteomics-based model derived from the training set, the area under the receiver operating characteristic curve was 0.81 (95% CI 0.73–0.88) in the test set (Figure 1). There were 632 differentially expressed proteins (univariable p<0.05). Pathway analysis identified significantly dysregulated pathways in patients with prior MACE (Figure 2). This included both pathways known to be associated with MACE (e.g., TGF-β [FDR=0.03]) and novel pathways (e.g., Ras-MAPK [FDR=0.01] and its upstream PI3K-Akt [FDR=7.7x10–7] pathways). Pathways involved in cellular metabolism/proliferation (e.g., HIF 1 [FDR=0.01] and Wnt [FDR=0.04] pathways) and inflammation (e.g., complement and coagulation cascades [FDR=2.7x10–21], cytokine-cytokine receptor interaction [FDR=8.1x10–16]) were also significantly dysregulated. Conclusions Our study in patients with HCM reveals that those with a prior history of MACE have a distinctive plasma proteomics profile. We further identified both previously known and novel pathways dysregulated in this subset with a more severe form of HCM. Our findings may aid in development of targeted therapies for the prevention of MACE in HCM. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): R01 HL157216