title: Effect of age and body weight on neurohumoral variables in healthy Cavalier King Charles spaniels.
abstract: OBJECTIVE
  To evaluate the effect of age and body weight on several neurohumoral variables that are commonly altered in heart failure in Cavalier King Charles Spaniels.
  
  
  METHODS
  17 healthy privately owned Cavalier King Charles Spaniels, 10 males and 7 females, ranging in age from 0.4 to 9.7 years, and ranging in body weight from 6.6 to 12.2 kg.
  
  
  METHODS
  The clinical condition of the dogs was evaluated by physical examination, thoracic radiography, and echocardiography. Plasma nitrate and nitrite (P-NN), N-terminal atrial natriuretic and brain natriuretic peptides (NT-ANP and BNP, respectively), endothelin (ET-1), urine cyclic guanosine monophosphate (U-cGMP), and urine nitrate and nitrite (U-NN) concentrations were analyzed.
  
  
  RESULTS
  Plasma concentrations of NT-ANP and P-NN increased significantly with age, but plasma NT-ANP and P-NN also correlated significantly, irrespective of age. A modest increase of left atrial size did not explain the increase of NT-ANP and P-NN with age. Concentration of ET-1 correlated positively with heart rate; heart rate did not change with age. Weight had a negative impact on NT-ANP, P-NN, and U-cGMP concentrations and left atrial relative size.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Clinical Veterinary Sciences, Faculty of Veterinary Medicine, Helsinki University, Finland.
authors.forename: A S
authors.initials: AS
authors.lastname: Eriksson
authors.forename: A K
authors.initials: AK
authors.lastname: Järvinen
authors.forename: K K
authors.initials: KK
authors.lastname: Eklund
authors.forename: O J
authors.initials: OJ
authors.lastname: Vuolteenaho
authors.forename: M H
authors.initials: MH
authors.lastname: Toivari
authors.forename: M S
authors.initials: MS
authors.lastname: Nieminen
mesh_terms: D000367:Age Factors; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000097:blood* / Q000652:urine; D001835:Body Weight; D002302:Cardiac Output; D003404:Creatinine / Q000652:urine; D006152:Cyclic GMP / Q000652:urine; D004285:Dogs / Q000097:blood / Q000502:physiology* / Q000652:urine; D004452:Echocardiography / Q000662:veterinary; D004562:Electrocardiography / Q000662:veterinary; D019332:Endothelin-1 / Q000097:blood; D005260:Female; D006333:Heart Failure / Q000097:blood / Q000652:urine; D006339:Heart Rate; D008297:Male; D020097:Natriuretic Peptide, Brain / Q000097:blood* / Q000652:urine; D018377:Neurotransmitter Agents / Q000097:blood / Q000652:urine; D009573:Nitrites / Q000097:blood / Q000652:urine; D013902:Radiography, Thoracic / Q000662:veterinary; D012044:Regression Analysis
chemical_list: D019332:Endothelin-1; D018377:Neurotransmitter Agents; D009573:Nitrites; D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor; D003404:Creatinine; D006152:Cyclic GMP