title: [Bactericidal permeability increasing protein inhibits lipopolysaccharide-mediated platelet activation in vitro].
abstract: This study was purposed to investigate the inhibitory effect of bactericidal permeability-increasing protein (BPI) on lipopolysaccharide (LPS)-mediated activation of platelets. Venous blood samples were obtained from 10 healthy volunteers and were prepared into platelet-rich plasma (PRP, 1 × 10(8)/ml). Experiments were divided into four groups: normal platelet group (untreated group); LPS group, BPI group and BPI+LPS group. PRP were stimulated by LPS (10 µg/ml) in the presence and absence of BPI (100 µg/ml) or BPI alone. Then platelets were harvested and determined for Toll-like receptor-4 (TLR-4) with flow cytometry (FCM), the supernatant was used for detection of cytokines including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) with enzyme-linked immunosorbent assay (ELISA). The results showed that as compared with normal platelet group, TLR-4 expression on platelets was significantly increased under LPS stimulation (P < 0.001); the levels of TNF-α and IL-6 in the supernatant were also remarkably elevated (P < 0.001). However, either TLR-4 expression or the cytokine levels significantly decreased in the presence of BPI when platelets underwent LPS-challenge (P < 0.05), but still were higher than that in normal platelet group. Stimulating the platelets with BPI alone could not enhance the TLR-4 expression and cytokine levels. It is concluded that BPI has the ability to inhibit the LPS-induced platelet activation.
authors.affiliation: Department of Hematology, Sun Yat-Sen University, Guangdong Province, China.
authors.forename: Xian-Ming
authors.initials: XM
authors.lastname: Luo
authors.forename: Qiu-Hong
authors.initials: QH
authors.lastname: Yang
authors.forename: Jing
authors.initials: J
authors.lastname: Wei
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Ma
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology*; D001798:Blood Proteins / Q000494:pharmacology*; D006801:Humans; D007249:Inflammation; D008070:Lipopolysaccharides / Q000009:adverse effects; D015539:Platelet Activation / Q000187:drug effects*; D053657:Platelet-Rich Plasma / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000378:metabolism
chemical_list: D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins; D008070:Lipopolysaccharides; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; C021623:bactericidal permeability increasing protein