Association of brain-type natriuretic protein and cardiac troponin I with incipient cardiovascular disease in chimpanzees (Pan troglodytes)

Cardiovascular disease (CVD) is the primary cause of morbidity and mortality in chimpanzees, but its etiology and clinical presentations remain poorly understood. The disease in chimpanzees differs sufficiently from that in humans that simple extrapolation from human findings are inadequate to guide clinical diagnoses. Nevertheless, the burden of disease posed by CVD made it important to attempt to identify specific chimpanzees at risk of developing CVD to allow clinical intervention prior to clinical presentation of advanced disease. We screened 4 CVD biomarkers used in human and veterinary medicine to identify markers with prognostic value in chimpanzees. Biomarkers included complete lipid panel, C-reactive protein, brain-type natriuretic protein, and cardiac troponin I. Serum levels of brain-type natriuretic protein differed between chimpanzees with CVD and heart-healthy controls. Cardiac troponin I gave mixed results. C-reactive protein and lipid panel values were not informative for cardiovascular disease, although total cholesterol, LDL-cholesterol, and triglycerides increased significantly with decade of life. Values of braintype natriuretic protein exceeding 163 mg/mL had a specificity of 90.5% for CVD, whereas levels of cardiac troponin I above the threshold of detection (0.20 ng/mL) appeared to be clinically relevant. More extensive clinical studies are recommended to validate these specific values. We conclude that brain-type natriuretic protein and possibly cardiac troponin I are useful diagnostic biomarkers for incipient CVD processes in chimpanzees.