Investigating the effect of a platelet additive solution on apheresis platelet and fibrin network ultrastructure

摘要

In thrombotic events and diseases such as cancer, HIV/AIDS, dysfibrinogenaemia, as well asacute incidents (e.g. burn wounds), ultrastructure of platelets and fibrin networks change.In the current study, we compare the ultrastructure of platelets and fibrin networks ofapheresis platelets stored in citrated human plasma (CP) and in a first-generation plateletadditive solution (PAS) (T-Sol), to that of fresh donor plasma (FP). Eighteen apheresis plateletdonors donated platelets on Trima -Accel™ V5.2 and V5.1 cell separators. Six collectionswere stored for five days in autologous citrated plasma (CP); six collections were stored in40% citrated human plasma and 60% PAS solution (CP/PAS) controlled, for the duration ofstorage, at a constant temperature (22 ± 2 C) with continuous flat-bed agitation; and sixcollections were stored in conditions uncontrolled for temperature and without continuousagitation. On days 1, 3 and 5, equal volumes of human thrombin were mixed with plateletscollected in either CP or CP/PAS to form a coagulum (fibrin network containing plateletaggregates), followed by preparation for scanning electron microscopy. Results were comparedwith platelets and fibrin networks in FP. Typically, in FP, platelet aggregates withsmooth membranes and pseudopodia are seen and fibrin networks arrange to form major,thick fibers and scattered, minor, thin fibers. On day 1, in CP and in all CP/PAS units, plateletultrastructure compared well to that of FP, although the fibrin fibers were denser, with theminor fibers forming a matted layer over the major fibers. On day 3, in platelet unitsuncontrolled for temperature and without continuous agitation during storage, someplatelet aggregates in CP/PAS showed typical apoptotic morphology, with shrinkage andmembrane damage, but comparable fibrin networks were present. On day 5 however, inthose units where storage conditions were uncontrolled and where the pH had decreasedto below 6.4, no platelet aggregates were seen and fibrin was arranged into short, lumpymasses with no separate major or minor fibrin fibers visible. In those units stored at22 C with continuous flat-bed agitation, where pH was maintained >7.0, ultrastructureof platelets and fibrin network in CP/PAS was typical and similar to FP and CP at the endof five days of storage. Examining platelet and fibrin network ultrastructure may be useful,in addition to conventional laboratory analysis, in assessing the viability and potentialclinical efficacy of platelets for transfusion and could play a role in the evaluation ofnew generation platelet additive solutions.