Small volume platelet concentrates for neonatal use are more susceptible to shear-induced storage lesion.

The impact of the biophysical environment on the platelet storage lesion (PSL) has mainly focused on reduced temperature storage, overlooking the significance of storage-induced shear stress. Shear stress in platelet storage refers to the frictional force acting parallel to the bag surface and exists solely through the implementation of agitation. This study investigates whether minimizing exposure to agitation-induced shear stress can alleviate the unexplained loss of function in stored platelet concentrates for neonatal transfusion (neonatal PCs). Using particle tracking analysis, fluid motion was measured in neonatal and adult platelet storage bags under agitation frequencies ranging from 20-60 rpm. Platelets stored at 20-60 rpm agitation over 8 days were examined by biochemical analysis, aggregation, and expression of activation markers. Results indicate that neonatal PCs experience significantly higher storage-induced shear stress compared to adult doses, leading to reduced functionality and increased activation from day 2 of storage. Adjusting the neonatal PC agitation frequency to 20 rpm improved functionality in early storage, while 40 rpm maintains this improvement throughout storage with reduced activation, compared to 60 rpm storage. This study confirms that small volume PC storage for neonatal use contributes to the PSL through the induction of shear stress, suggesting further evaluation of the recommended agitation frequency for neonatal PCs or postponement of the production of neonatal PCs until requested for neonatal transfusion.

Context Approximately 1­5% of all neonates and up to 50% of critically ill newborns, present with low platelet counts, and will require platelet transfusion support.Platelet concentrates stored for neonatal transfusion have previously shown an accelerated reduction in quality during storage compared to platelet concentrates stored for adult transfusion and therefore may not provide as effective a therapeutic product.The current study hypothesized this loss of function over storage (known as the platelet storage lesion) to be a result of shear stress induced by agitation, exacerbated by the use of smaller bags in the neonatal preparation.Findings Our findings show that storage of platelet concentrates as smaller bags suitable for neonatal transfusion accelerates the platelet storage lesion, which experience a 4-fold greater shear stress than the adult preparation.The shear stress experienced by platelet concentrates stored for neonatal transfusion could be reduced by reducing the speed of agitation, thereby reducing the extent of the platelet storage lesion.Impact This study provides evidence that small volume storage promotes shear stress in platelet concentrates stored for neonatal transfusion, and optimizing storage conditions to reduce the shear stress induced by agitation can help to offset the platelet storage lesion.Further evaluation is required to establish a recommended agitation frequency for platelet concentrates stored for neonatal transfusion. An alternative strategy might include postponement of the production of platelet concentrates for neonatal transfusion until a neonatal transfusion is requested.

Cold stored platelets in the management of bleeding: is it about bioenergetics?

When platelet concentrates (PCs) were first introduced in the 1960s as a blood component therapy, they were stored in the cold. As platelet transfusion became more important for the treatment of chemotherapy-induced thrombocytopenia, research into ways to increase supply intensified. During the late 1960s/early 1970s, it was demonstrated through radioactive labeling of platelets that room temperature platelets (RTP) had superior post-transfusion recovery and survival compared with cold-stored platelets (CSP). This led to a universal switch to room temperature storage, despite CSP demonstrating superior hemostatic effectiveness upon being transfused. There has been a global resurgence in studies into CSP over the last two decades, with an increase in the use of PC to treat acute bleeding within hospital and pre-hospital care. CSP demonstrate many benefits over RTP, including longer shelf life, decreased bacterial risk and easier logistics for transport, making PC accessible in areas where they have not previously been, such as the battlefield. In addition, CSP are reported to have greater hemostatic function than RTP and are thus potentially better for the treatment of bleeding. This review describes the history of CSP, the functional and metabolic assays used to assess the platelet storage lesion in PC and the current research, benefits and limitations of CSP. We also discuss whether the application of new technology for studying mitochondrial and glycolytic function in PC could provide enhanced understanding of platelet metabolism during storage and thus contribute to the continued improvements in the manufacturing and storage of PC.

What is the context? To transition into an activated state, platelets require a highly efficient source of energy that is met through the production of ATP ­ this is referred to as "platelet bioenergetics"Platelets can be removed from healthy donors and used to make platelet concentrates for clinical usePlatelet concentrates are used clinically either therapeutically (to halt bleeding) or prophylactically (to prevent bleeding in patients with low platelet counts)They are stored at room temperature (20­24^oC) with constant gentle agitation, in packs that allow gas exchange and have a 7-day shelf life in some jurisdictionsStoring platelets in the cold (2­6^oC) has historically been shown to improve their ability to halt bleedingWhat is new? There is a renewed interest in cold stored platelets for use in actively bleeding patientsThere are benefits to cold-storing platelets over room temperature storageCold stored platelets are licensed in the US and Norway for certain indications for 14 daysWhat is next? Cold stored platelets have the potential to improve logistics of clinical supply of platelets, enable supply of platelet concentrates where access is currently limited, such as pre-hospital care and on the battlefield and provide improved hemostatic effects for bleeding patients.New research measuring the bioenergetic profiles of cold stored platelets could advance understanding of metabolism in cold stored platelets and support decisions on their re-introduction on a wider scale.