Determinants of platelet conjugate formation with polymorphonuclear leukocytes or monocytes in whole blood.
Following preliminary in-vitro experiments, platelet-leukocyte conjugates and their determinants were evaluated in citrated whole blood from 349 subjects (209 women, age 16-92 years) randomly recruited from the general population. Platelet activation by ADP/collagen but not leukocyte stimulation by fMLP or LTB4 resulted in formation of platelet conjugates with PMN or monocytes. In the population study, mixed cell conjugates, platelet P-selectin and leukocyte CD11b were measured by flow cytometry both at baseline and after in-vitro stimulation with ADP/collagen. The latter significantly increased platelet conjugates with either PMN or monocytes, platelet P-selectin and leukocyte CD11b expression. Platelet count significantly correlated with platelet-PMN, platelet-monocyte conjugates and P-selectin both at baseline and upon stimulation. In all conditions, both conjugate levels correlated with each other, when adjusted for gender, age and platelet count. Age correlated with platelet-PMN conjugate numbers in basal and stimulated conditions and with basal P-selectin. ADP/collagen stimulation resulted in higher P-selectin and conjugates values in women. Among risk factors, a significant correlation was found between conjugate and glucose levels. In conclusion, the presence and formation in whole blood from a large population of platelet-leukocyte conjugates reflects primary platelet - but not leukocyte - activation and varies with gender, age, platelet count and blood glucose.
Research Laboratories, John Paul II Center for High Technology Research and Education, Largo Gemelli 1, 86100 Campobasso, Italy.
Benedetta
B
Izzi
Agnieszka
A
Pampuch
Simona
S
Costanzo
Branislav
B
Vohnout
Licia
L
Iacoviello
Chiara
C
Cerletti
Giovanni
G
de Gaetano
D000244:Adenosine Diphosphate / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D001792:Blood Platelets / Q000378:metabolism*; D039481:CD11b Antigen; D003094:Collagen / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007975:Leukotriene B4 / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism*; D009203:Myocardial Infarction / Q000097:blood* / Q000209:etiology; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D019007:P-Selectin / Q000378:metabolism; D015539:Platelet Activation / Q000187:drug effects; D010973:Platelet Adhesiveness / Q000187:drug effects; D010976:Platelet Count; D011159:Population Surveillance; D012737:Sex Factors
D001786:Blood Glucose; D039481:CD11b Antigen; C509295:ITGAM protein, human; D019007:P-Selectin; D007975:Leukotriene B4; D009240:N-Formylmethionine Leucyl-Phenylalanine; D000244:Adenosine Diphosphate; D003094:Collagen