Reference values for cardiac hormones in young Japanese macaques (Macaca fuscat)

Spontaneous cardiac disease in nonhuman primates offers a useful model of human cardiac disease. However, diagnosing heart disease generally requires specialized techniques such as ultrasonography. This study focused on cardiac hormones that can be used to detect cardiac disease from blood tests. We measured concentrations of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in healthy young Japanese macaques (Macaca fuscata) housed individually indoors, with no abnormalities in thoracic X-rays, electrocardiograms, echocardiograms, or complete blood counts and serum biochemistry tests, to establish reference values. The monkeys used in this study comprised 29 males (28-47 months old) and 29 females (22-65 months old). ANP levels were determined by immunoradiometric assay. BNP levels were determined by chemiluminescent enzyme immunoassay. Mean ANP level was 25.7 ± 9.6 pg/mL for all 58 Japanese macaques, 26.7 ± 9.6 pg/mL for the 29 males, and 24.7 ± 9.5 pg/mL for the 29 females. No significant difference was identified between sexes. No correlation was seen between ANP and age but excluded monkeys showed result of outside these range. BNP was also measured, with 22 of the 58 monkeys showing levels below the lower limit of detection (<4.0 pg/mL). Taking levels in these 22 animals as 4.0 pg/mL, mean BNP level was 5.1 ± 1.6 pg/mL and BNP elevated in two excluded monkeys. These results establish mean values for cardiac hormones in young Japanese macaques. These standards may provide useful indicators for the early detection of cardiac disease in animal models.