Lipidomic changes occurring in platelets during extended cold storage.

OBJECTIVES: Cold storage is being implemented as an alternative to conventional room-temperature storage for extending the shelf-life of platelet components beyond 5-7 days. The aim of this study was to characterise the lipid profile of platelets stored under standard room-temperature or cold (refrigerated) conditions. METHODS: Matched apheresis derived platelet components in 60% PAS-E/40% plasma (n = 8) were stored at room-temperature (20-24°C with agitation) or in the cold (2-6°C without agitation). Platelets were sampled on day 1, 5 and 14. The lipidome was assessed by ultra-pressure liquid chromatography ion mobility quadrupole time of flight mass spectrometry (UPLC IMS QToF). Changes in bioactive lipid mediators were measured by ELISA. RESULTS: The total phospholipid and sphingolipid content of the platelets and supernatant were 44 544 ± 2915 µg/mL and 38 990 ± 10 880 µg/mL, respectively, and was similar over 14 days, regardless of storage temperature. The proportion of the procoagulant lipids, phosphatidylserine (PS) and phosphatidylethanolamine (PE), increased by 2.7% and 12.2%, respectively, during extended cold storage. Cold storage for 14 days increased sphingomyelin (SM) by 4.1% and decreased ceramide by 1.6% compared to day 1. Further, lysophosphatidylcholine (LPC) species remained unchanged during cold storage for 14 days. The concentration of 12- and 15-hydroxyeicosatetraenoic acid (HETE) were lower in the supernatant of cold-stored platelets than room-temperature controls stored for 14 days. CONCLUSION: The lipid profile of platelets was relatively unchanged during storage for 5 days, regardless of temperature. However, during extended cold storage (14 days) the proportion of the procoagulant lipids, PS and PE, increased, while LPC and bioactive lipids were stable.

The Lipid Composition of Platelets and the Impact of Storage: An Overview.

Lipids and bioactive lipid mediators are essential for platelet function. The lipid profile of platelets is highly dynamic due to free exchange of lipids with the plasma, release of extracellular vesicles, and both enzymatic and nonenzymatic lipid conversion. The lipidome of platelets changes in response to activation to accommodate the functional requirements of platelets, particularly for maintenance of hemostasis. Furthermore, when stored at room temperature as a component for transfusion, the lipid profile of platelets is altered. Although there is a growing interest in alternate storage conditions, such as refrigeration and cryopreservation, few contemporary studies have examined the impact of these storage modes on the lipid profile. However, evidence exists that bioactive lipid mediators produced over the storage of blood products may have functional implications once these products are transfused. As such, there is a need to determine the changes occurring to the lipid profile of these products over storage. This review outlines the role of lipids in platelets and discusses the current state of lipidomics for studying platelet components for transfusion in an effort to highlight the necessity for additional transfusion-focused investigations.

The nature and dissemination of UHMWPE wear debris retrieved from periprosthetic tissue of THR.

The role of wear debris in provoking joint replacement failure through bone resorption is now supported by much research. This study presents the analysis of 104 tissue samples using laser diffraction wear particle analysis in conjunction with standard histologic methods. The number and volume distributions were correlated to a range of joint and patient parameters. The median particle diameter by number was 0.69 microm. No particles smaller than 0.113 microm were resolved. No variation in terms of particle distribution was found among joint types. The ability of particles to migrate away from their point of origin was found to be inversely proportional to their size. The numbers of particles per gram of tissue found in various regions around the prosthesis varied little. Further, the numbers of particles in tissue samples shown to have a chronic foreign-body reaction was > 1 x 10(9) particles/gram.

The dynamic volume changes of polymerising polymethyl methacrylate bone cement.

The Swedish hip register found an increased risk of early revision of vacuum-mixed cemented total hip replacements. The influence of cement mixing technique on the dynamic volume change in polymerising PMMA is not well understood and may be relevant to this observation. Applying Archimedes' principle, we have investigated the dynamic volume changes in polymerising cement and determined the influence of mixing technique. All specimens showed an overall volume reduction: hand-mixed 3.4% and vacuum-mixed 6.0%. Regression analysis of sectional porosity and volume reduction showed a highly significant relationship. Hand-mixed porous cement showed a transient volume increase before solidification. However, vacuum-mixed cement showed a progressive volume reduction throughout polymerisation. Transient expansion of porous cement occurs at the critical time of micro-interlock formation, possibly improving fixation. Conversely, progressive volume reduction of vacuum-mixed cement throughout the formation of interlock may damage fixation. Stable fixation of vacuum-mixed cement may depend on additional techniques to offset the altered volumetric behaviour of vacuum-mixed cement.