| First Author | Sharron M | Year | 2012 |
| Journal | PLoS One | Volume | 7 |
| Issue | 7 | Pages | e41549 |
| PubMed ID | 22844498 | Mgi Jnum | J:189717 |
| Mgi Id | MGI:5446881 | Doi | 10.1371/journal.pone.0041549 |
| Citation | Sharron M, et al. (2012) Platelets induce apoptosis during sepsis in a contact-dependent manner that is inhibited by GPIIb/IIIa blockade. PLoS One 7(7):e41549 |
| abstractText | PURPOSE: End-organ apoptosis is well-described in progressive sepsis and Multiple Organ Dysfunction Syndrome (MODS), especially where platelets accumulate (e.g. spleen and lung). We previously reported an acute sepsis-induced cytotoxic platelet phenotype expressing serine protease granzyme B. We now aim to define the site(s) of and mechanism(s) by which platelet granzyme B induces end-organ apoptosis in sepsis. METHODS: End-organ apoptosis in murine sepsis (i.e. polymicrobial peritonitis) was analyzed by immunohistochemistry. Platelet cytotoxicity was measured by flow cytometry following 90 minute ex vivo co-incubation with healthy murine splenocytes. Sepsis progression was measured via validated preclinical murine sepsis score. MEASUREMENTS AND MAIN RESULTS: There was evident apoptosis in spleen, lung, and kidney sections from septic wild type mice. In contrast, there was a lack of TUNEL staining in spleens and lungs from septic granzyme B null mice and these mice survived longer following induction of sepsis than wild type mice. In co-incubation experiments, physical separation of septic platelets from splenocytes by a semi-permeable membrane reduced splenocyte apoptosis to a rate indistinguishable from negative controls. Chemical separation by the platelet GPIIb/IIIa receptor inhibitor eptifibatide decreased apoptosis by 66.6+/-10.6% (p = 0.008). Mice treated with eptifibatide in vivo survived longer following induction of sepsis than vehicle control mice. CONCLUSIONS: In sepsis, platelet granzyme B-mediated apoptosis occurs in spleen and lung, and absence of granzyme B slows sepsis progression. This process proceeds in a contact-dependent manner that is inhibited ex vivo and in vivo by the platelet GPIIb/IIIa receptor inhibitor eptifibatide. The GPIIb/IIIa inhibitors and other classes of anti-platelet drugs may be protective in sepsis. |
