Evaluation of inflammatory and fibrosis biomarkers at different stages of degenerative mitral valve disease in dogs

Degenerative mitral valve disease is the most prevalent heart disease in dogs. Research on biomarkers of heart diseases has increased recently owing to their value in providing complementary information to gold standard diagnostic methods and enhancing the understanding of pathophysiology. Novel biomarkers, such as Galectin-3 (Gal-3), soluble interleukin-1 receptor-like 1 protein (sST2), and growth differentiation factor 15 (GDF-15), have demonstrated prognostic value in human medicine but are poorly studied in veterinary medicine. The purpose of this study was to determine the serum concentrations of these novel inflammatory biomarkers, along with traditional biomarkers, in dogs at different stages of degenerative mitral valve disease. Thirty-eight dogs were included: 14 in stage A, 10 in stage B2, and 14 in stage C. Serum concentrations of five biomarkers (Gal-3, sST2, GDF-15, fibrinogen, and C-reactive protein), echocardiography, thoracic radiography, clinical chemistry, and blood cell counts were assessed for each dog. Differences in biomarker concentrations between groups were analyzed. Fibrinogen and C-reactive protein concentrations were higher in group C than in group A. Galectin-3 concentrations were higher in group B2 compared to those in group C. GDF 15 concentrations were higher in group B2 than in group A. No significant differences were found between groups B2 and C. sST2 concentrations did not differ between the groups. In conclusion, the novel inflammatory biomarker GDF-15 was measurable in dogs and was elevated in stage B2, similar to Gal-3, suggesting that inflammation and fibrosis begin with cardiac remodeling before clinical signs appear. Classical biomarkers showed the expected behavior. Further studies are needed to determine whether treatment affects the behavior of novel biomarkers.