Effects of mechanical ventilation on platelet microparticles in bronchoalveolar lavage fluid.
BACKGROUND
Mechanical ventilation (MV) is considered to contribute to lung injury. Platelet membrane-derived microparticles (PMPs) are procoagulant and participate in the inflammatory process. The bronchoalveolar space could, besides plasma, be a site of origin of these microparticles. We evaluated the presence of these PMPs and two prostaglandin-derived metabolites in bronchoalveolar lavage fluid (BALF) regarding their possible relation to MV.


METHODS
Before and after 1 h of MV, PMPs and prostaglandin metabolites were analyzed, in BALF from 14 anesthetized pigs, by flow cytometry and RIA, respectively. Tracheal mucus from five humans was analyzed for PMPs at extubation after surgery.


RESULTS
Activated PMPs and prostaglandin metabolites were present in all BALF samples. The time needed to count 5000 cellular events was prolonged six-fold after 1 h of mechanical ventilation (p<0.001). The relative content of PMPs was constant in all samples. The PMPs were thrombogenic, i.e. they were fibrinogen, p-selectin and von Willebrand factor positive. Lavage did not per se affect the period necessary to count 5000 cellular events. PMPs in human tracheal mucus were in the same range as in the pig after 1 h of MV aiming at a PaCO(2) between 5.0 and 5.5 kPa.


CONCLUSIONS
Activated PMPs are present in the pulmonary air-liquid interface. The prolongation of the time needed to count 5000 cellular events in BALF after MV indicates activation and adherence. Adherent microparticles bind neutrophils, which may aggravate pathological processes leading to pulmonary dysfunction. Evaluation of PMPs in BALF may be useful in evaluating strategies for lung-protective ventilator treatment.
Mutschler
Diana K
DK
Department of Surgical Sciences, Faculty of Medicine, Uppsala University Hospital, Sweden.
Larsson
Anders O
AO
Basu
Samar
S
Nordgren
Anders
A
Eriksson
Mats B
MB
D000368:Aged; D000818:Animals; D001792:Blood Platelets / Q000378:metabolism*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry*; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000378:metabolism; D028441:F2-Isoprostanes / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D010316:Particle Size; D015539:Platelet Activation; D010979:Platelet Function Tests; D011863:Radioimmunoassay / Q000379:methods; D012121:Respiration, Artificial / Q000379:methods*; D013552:Swine; D013997:Time Factors
D028441:F2-Isoprostanes; C008228:15-keto-13,14-dihydroprostaglandin F2alpha; C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost