Potential role of platelet FcgammaRIIA in collagen-mediated platelet activation associated with atherothrombosis.
Collagen-mediated platelet activation contributes significantly to coronary and cerebrovascular thrombus formation associated with atherosclerotic plaque destabilization. Recent clinical and laboratory observations support a potential role for the platelet Fc receptor (FcgammaRIIA) in this process. The purpose of this study was to elucidate any association between platelet Fc receptor (FcR) expression levels and both atherosclerosis risk factors (ARFs) along with collagen-dependent platelet activation. Age and gender-independent variation has been described in the expression of this receptor that is stable over time. Platelet Fc surface expression was compared between patients experiencing an acute coronary or cerebrovascular event, healthy patients with two or more ARFs, and healthy patients with fewer than two ARFs. Platelet FcR expression was significantly and stably (6-52 weeks, mean 20 weeks) increased in 101 patients with acute myocardial infarction, unstable angina, or ischemic stroke syndrome (P<0.001) and 38 healthy patients with two or more ARFs (P=0.027) compared with 109 healthy patients with fewer than two ARFs. Patients with diabetes mellitus from all groups had significantly increased platelet FcR expression over those without diabetes (P<0.0001). Platelet aggregation studies suggested a correlation between number of ARFs per patient, platelet Fc expression levels, and relative sensitivity to collagen stimulation. Platelet FcR surface expression is increased in patients with an acute coronary or cerebrovascular event, non-acutely ill patients with two or more ARFs, and in patients with diabetes mellitus. Increased platelet FcR expression may therefore contribute towards risk for atherothrombotic events.
Calverley
David C
DC
Department of Medicine and the Mountain States Regional Hemophilia and Thrombosis Center, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, Box B171, Denver, CO 80262, USA. david.calverley@uchsc.edu
Brass
Elizabeth
E
Hacker
Michele R
MR
Tsao-Wei
Denice D
DD
Espina
Byron M
BM
Pullarkat
Vinod A
VA
Hodis
Howard N
HN
Groshen
Susan
S
D000328:Adult; D000367:Age Factors; D000368:Aged; D000789:Angina, Unstable / Q000097:blood; D001161:Arteriosclerosis / Q000097:blood / Q000473:pathology*; D001792:Blood Platelets / Q000378:metabolism* / Q000502:physiology; D016022:Case-Control Studies; D003094:Collagen / Q000494:pharmacology*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood; D015539:Platelet Activation; D010974:Platelet Aggregation; D011336:Probability; D011961:Receptors, Fc / Q000032:analysis / Q000378:metabolism*; D012016:Reference Values; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012737:Sex Factors; D020521:Stroke / Q000097:blood
D011961:Receptors, Fc; D003094:Collagen