Equine BNP measurement using a porcine BNP enzyme-linked immunoassay: a pilot study

Brain natriuretic peptide (BNP) is used in human medicine for the diagnosis of congestive heart failure. Since BNP is species-specific and no equine assay is available, BNP has never been determined in horses. Because there is more than 90% homology between porcine and equine BNP, a porcine BNP enzyme-linked immunoassay (ELISA) was used in the present study to measure BNP in plasma of healthy horses (group 1; n=20), horses with cardiac disease without (group 2a; n=8) and with atrial dilatation (n=8), ventricular dilatation (n=1) or both (n=1) (group 2b; n=10). Samples were stored at -20 degrees C and -80 degrees C to study the influence of storage temperature. No significant differences were found between the BNP concentrations of group 1 (77.79; 37.20-513.36 pg/mL), group 2a (52.02; 24.69-268.37 pg/mL) or 2b (94.73; 42.88-470.66 pg/mL). Samples stored at -80 degrees C showed significantly (72.19, 24.69-513.36 pg/mL; P=0.001) higher concentrations than samples stored at -20 degrees C (47.35, 24.69-430.60 pg/mL). In this pilot study, it is suggested that the porcine BNP assay does not allow accurate detection of equine BNP. An equine specific BNP assay should be developed to study BNP concentrations in horses