Platelet-neutrophil aggregate formation in blood samples from dogs with systemic inflammatory disorders.
OBJECTIVE
To evaluate platelet-neutrophil aggregate (PNA) formation and neutrophil shape as indicators of neutrophil activation in dogs with systemic inflammatory diseases and after blood sample incubation with various platelet and neutrophil agonists.


METHODS
20 dogs with systemic inflammatory response syndrome (SIRS) and 10 healthy Beagles.


METHODS
Neutrophils were isolated from blood samples directly after blood sample collection and after incubation of blood samples with phorbol myristate acetate, collagen, adenosine diphosphate, epinephrine, or various concentrations of lipopolysaccharide or arachidonic acid. CD61+ neutrophils as an indicator of PNA formation were evaluated, and neutrophil size and granularity were assessed via flow cytometry.


RESULTS
Dogs with SIRS had more PNA formation, larger neutrophil size, and less granularity relative to control dogs, but no differences were evident when these dogs were grouped by whether they had sepsis (n = 6) or disseminated intravascular coagulation (12). A significant increase in PNA formation occurred after neutrophil incubation with all agonists, and incubation with phorbol myristate acetate elicited the strongest response. Neutrophils increased in size and decreased in granularity after incubation with all agonists except epinephrine. Incubation with lipopolysaccharide or arachidonic acid resulted in a dose-dependent effect on PNA formation and neutrophil shape.


CONCLUSIONS
SIRS appeared to increase the degree of PNA formation and neutrophil shape change. Similar changes after neutrophil incubation with platelet agonists suggested that platelet activation has a role in PNA formation. Additional studies are necessary to determine the clinical importance and diagnostic value of PNA formation in dogs with SIRS and sepsis.
Small Animal Clinic, University of Veterinary Medicine Hanover, 30559 Hanover, Germany.
Brigitte Hedwig
BH
Dircks
Reinhard
R
Mischke
Hans-Joachim
HJ
Schuberth
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology; D001792:Blood Platelets / Q000276:immunology*; D003094:Collagen / Q000494:pharmacology; D004283:Dog Diseases / Q000097:blood* / Q000276:immunology*; D004285:Dogs; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D005434:Flow Cytometry / Q000662:veterinary; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D018375:Neutrophil Activation / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology*; D010974:Platelet Aggregation / Q000276:immunology*; D011446:Prospective Studies; D018709:Statistics, Nonparametric; D018746:Systemic Inflammatory Response Syndrome / Q000097:blood / Q000276:immunology / Q000662:veterinary*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D008070:Lipopolysaccharides; D016718:Arachidonic Acid; D000244:Adenosine Diphosphate; D003094:Collagen; D013755:Tetradecanoylphorbol Acetate; D004837:Epinephrine