Role of extracellular mitochondria in adverse transfusion reactions
Platelets are playing critical roles in hemostasis, and transfusion of platelets is a life-saving therapeutical procedure for patients undergoing a major surgery, with massive bleedings, for subjects withabnormal platelets (not fully functional) and diseases such as cancers or thrombocytopenia.For platelet transfusion, it is necessary to prepare, store and maintain platelet concentrates. Platelets concentrates have a short shelf life and must be conserved at ambient temperature- ideal for bacterial growth.Bacterial contamination of platelet concentrates represents the major cause of morbidity and mortality in transfusion. However, the bacterial agent causing these effects remains to identify, and the plateletsthemselves might secrete inflammatory mediators promoting adverse reactions.
Recently, we found that platelets release their mitochondria in the extracellular milieu during storage in platelet concentrates serving for transfusion (findings protected by a patent held by Université Laval).Mitochondria are thought to originate from the endosymbiosis of proteobacterium (Alphaproteobacterium Rickettsia prowazekii) during the development of the eukaryotic cells. We thus hypothesized that mitochondria might be the causal agent behind the transfusion inflammatory reactions. In this study, we aim to verify the presence of mitochondria and mitochondrial derived molecules in thetransfused platelet concentrates in a prospective cohort study in order to link these prospective biomarkers with adverse effects. We will collaborate with the haematologists in charge of transfusion and will use state-of-the-art methods of quantification of soluble mitochondria in platelet storage bags. Our goal is to determine whether our simple tests can serve to assess platelet quality to limit transfusion adverse reactions.