Effect of age and body weight on neurohumoral variables in healthy Cavalier King Charles Spaniels

Abstract

Age-matched controls are essential for evaluation of NT-ANP and P-NN concentrations and left atrial size. Weight may alter reference values of plasma NT-ANP, P-NN, and urine cGMP concentrations. Natriuretic peptides can be used as further evidence that heart failure exists. The increased plasma concentrations of NT-ANP (but not BNP) and P-NN with aging reflect neurohumoral physiologic changes that must be distinguished from pathologic changes in patients with heart failure.

Increased NT-proANP predicts risk of congestive heart failure in Cavalier King Charles spaniels with mitral regurgitation caused by myxomatous valve disease

“…6,15,35 Briefly, antibodies were raised in rabbits against human proANP-(79e98), which is identical to the corresponding sequence in the dog, except for amino acid number 95. NT-proANP was determined directly from plasma.…”

“…15 Briefly, nitrate (NO 3 ) was enzymatically converted to nitrite (NO 2 ), Griess reagents were added and absorbance (l ¼ 560 nm) measured. Standard curves with added known concentrations of NO 3 coincided with expected values.…”

“…As an example, cross-sectional methods compare means (or ranks) between groups and are not designed to detect individual trends over time. Moreover, age 15 and decreased renal function, 16e18 both of which may affect plasma levels of natriuretic peptides, may confound results. To reduce the impact of these factors this study uses longitudinal analyses that are able to account for time-varying covariates and individual trends over time.…”

“…The effect of NO is Abbreviations ACEI angiotensin converting enzyme inhibitor AIC Akaike's information criterion cGMP cyclic guanosine monophosphate CHF congestive heart failure CI confidence interval CKCS Cavalier King Charles spaniels eNOS endothelial nitric oxide synthase HPLC high-performance liquid chromatography HR hazard ratio LA/Ao left atrium to aortic root ratio MMVD myxomatous mitral valve disease MR mitral regurgitation NO nitric oxide NOx nitric oxide end-products, nitrite and/or nitrate NT-proANP N-terminal pro-A-type (or atrial) natriuretic peptide NT-proBNP N-terminal pro-B-type (or brain) natriuretic peptide NYHA New York Heart Association SD standard deviation SVEP Scandinavian Veterinary Enalapril Prevention study mediated via the same secondary messenger, cyclic guanosine monophosphate (cGMP), as for natriuretic peptide signaling and NO can be measured as the soluble metabolites nitrate and nitrite (NOx). 15 Under normal circumstances endothelial nitric oxide synthase (eNOS) produces NO to induce vasodilation and inhibit aggregation of thrombocytes. 20 In hypoxia and inflammation, however, the inducible form (iNOS) produces NO in excess.…”

“…21,22 In healthy dogs plasma NOx levels correlate with NT-proANP concentrations and increases with age. 15 Indices of increased tissue activity have been reported in the mitral valves in dogs with MMVD, 23 and signs of endothelial dysfunction have been observed in dogs with MMVD through necropsy material, 24,25 by peripheral blood flow measurements, 26,27 and through analysis of plasma cGMP or precursors 28 and end-products 29 to NO. However, to our knowledge, there are no data on changes and trends in endothelial function with regard to the progression of MMVD.…”