Understanding Pathophysiological Complexity of Feline Hypertrophic Cardiomyopathy Using SWATH-MS Plasma Proteomics

Establishing plasma biomarkers in the veterinary field has always been a challenge, due to a lack of significant understanding of pathophysiological attributes of disease. Advances in mass spectrometry-based proteomic techniques have improved plasma biomarker discovery in veterinary medicine. Feline hypertrophic cardiomyopathy is the most common cardiac disease in cats and has a complex and not fully elucidated pathophysiology. This study aimed to use SWATH-MS proteomics to identify novel plasma biomarkers for fHCM and to further elucidate disease pathogenesis. Plasma was collected from 20 cats, consisting of healthy controls (<i>n</i> = 10) and a HCM group <i>(n</i> = 10). Cats with fHCM, were diagnosed by echocardiography and disease statuses were determined by a veterinary cardiologist. Undepleted cat plasma samples were digested using FASP and quantitative analysis was performed using DIA-NN. A total of 40 plasma proteins were found to be dysregulated, primarily associated with innate and humoral responses, including complement C7 and C9 and properdin proteins. Other dysregulated proteins were involved in blood coagulation (fibrinogen, fibulin-1), lipid metabolism (apolipoproteins), and inflammation pathways (transthyretin and plasminogen). These findings provide possible biomarkers for fHCM, with the potential to detect disease before clinical signs become evident, which is a significant outcome for fHCM. These proteomic changes suggest critical pathways for earlier intervention and could potentially lead to more effective treatment outcomes. Furthermore, having significant similarity to human disease strengthens the case for using cats as a potential translational model for hHCM.