Platelet function in dogs: breed differences and effect of acetylsalicylic acid administration.
BACKGROUND
Clinical studies investigating platelet function in dogs have had conflicting results that may be caused by normal physiologic variation in platelet response to agonists.


OBJECTIVE
The objective of this study was to investigate platelet function in clinically healthy dogs of 4 different breeds by whole-blood aggregometry and with a point-of-care platelet function analyzer (PFA-100), and to evaluate the effect of acetylsalicylic acid (ASA) administration on the results from both methods.


METHODS
Forty-five clinically healthy dogs (12 Cavalier King Charles Spaniels [CKCS], 12 Cairn Terriers, 10 Boxers, and 11 Labrador Retrievers) were included in the study. Platelet function was assessed by whole-blood aggregation with ADP (1, 5, 10, and 20 microM) as agonist and by PFA-100 using collagen and epinephrine (Col + Epi) and Col + ADP as agonists. Plasma thromboxane B(2) concentration was determined by an enzyme immunoassay. To investigate the effect of ASA, 10 dogs were dosed daily (75 or 250 mg ASA orally) for 4 consecutive days.


RESULTS
A higher platelet aggregation response was found in CKCS compared to the other breeds. Longer PFA-100 closure time (Col + Epi) was found in Cairn Terriers compared to Boxers. Plasma thromboxane B(2) concentration was not statistically different between groups. Administration of ASA prolonged the PFA-100 closure times, using Col + Epi (but not Col + ADP) as agonists. Furthermore, ASA resulted in a decrease in whole-blood platelet aggregation.


CONCLUSIONS
Platelet function is influenced by breed, depending upon the methodology applied. However, the importance of these breed differences remains to be investigated. The PFA-100 method with Col + Epi as agonists, and ADP-induced platelet aggregation appear to be sensitive to ASA in dogs.
Nielsen
Line A
LA
Department of Animal and Veterinary Basic Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark. lini@novozymes.com
Zois
Nora E
NE
Pedersen
Henrik D
HD
Olsen
Lisbeth H
LH
Tarnow
Inge
I
D000818:Animals; D001241:Aspirin / Q000494:pharmacology*; D001792:Blood Platelets / Q000187:drug effects* / Q000502:physiology*; D002478:Cells, Cultured; D004285:Dogs / Q000145:classification* / Q000235:genetics / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006262:Health; D008297:Male; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D019095:Point-of-Care Systems