Hypertrophic cardiomyopathy (HCM) is the most common cardiomyopathy in cats. The diagnosis can be difficult, requiring advanced echocardiographic skills. Additionally, circulating biomarkers (N-terminal pro-B type natriuretic peptide and cardiac troponin I) have several limitations when used for HCM screening. In previous work, we identified interleukin 18 (IL-18), insulin-like growth factor binding protein 2 (IGFBP-2), brain-type glycogen phosphorylase B (PYGB), and WNT Family Member 5 A (WNT5A) as myocardial genes that show significant differential expression between cats with HCM and healthy cats. The products of these genes are released into the circulation, and we hypothesized that IL-18, IGFBP-2, PYGB, and WNT5A serum RNA and protein concentrations differ between healthy cats, cats with subclinical HCM, and those with HCM and congestive heart failure (HCM + CHF). Reverse transcriptase quantitative polymerase chain reaction (RTqPCR) and enzyme-linked immunosorbent assay (ELISA) were applied to evaluate gene and protein expression, respectively, in the serum of eight healthy controls, eight cats with subclinical HCM, and six cats with HCM + CHF. Serum IGFBP-2 RNA concentrations were significantly different among groups and were highest in cats with subclinical HCM. Compared to healthy controls, serum IL-18 and WNT5A gene expression were significantly higher in cats with HCM + CHF, and WNT5A was higher in cats with subclinical HCM. No differences were observed for PYGB. These results indicate that further investigation via large scale clinical studies for IGFBP-2, WNT5A, and IL-18 may be valuable in diagnosing and staging feline HCM.
Keywords: Biomarkers; Congestive heart failure; Feline; Gene expression; Hypertrophic cardiomyopathy; Serum RNA.
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