Helen Awatefe

Periods without agitation diminish platelet mitochondrial function during storage

BACKGROUND: Prolonged periods without agitation produce platelet (PLT) storage lesions that result in reduced in vitro assay parameters and an increase of apoptotic markers during storage. The aim of this study was to evaluate the influence of periods without agitation on PLT mitochondrial function, blood gases, and activation.

Maintenance of platelet in vitro properties during 7-day storage in M-sol with a 30-hour interruption of agitation

BACKGROUND: Extensive periods without agitation can occasionally occur during platelet (PLT) shipment and can affect PLT quality during 5‐ to 7‐day storage. The use of buffer‐containing PLT additive solutions (ASs) may better preserve PLT quality during storage by maintaining PLT pH and other in vitro variables. A newly described bicarbonate‐containing AS, M‐sol, was compared to plasma for preservation of whole blood–derived PLT concentrates in which a 30‐hour interruption of agitation was included.

Use of a flexible thiopyrylium photosensitizer and competitive inhibitor for pathogen reduction of viruses and bacteria with retention of red cell storage properties.

BACKGROUND: Progress in developing photochemical methods for pathogen reduction of red blood cells (RBCs) has been hampered by hemolysis. A flexible, nucleic acid‐intercalating thiopyrylium (TP) dye that is only photochemically active in the bound state and a competitive inhibitor of RBC membrane binding, dipyridamole (DP), was used to reduce photoinduced hemolysis stemming from free‐ and membrane‐bound dye.

An Inhibition of p38 Mitogen Activated Protein Kinase Delays the Platelet Storage Lesion

Background and Objectives Platelets during storage undergo diverse alterations collectively known as the platelet storage lesion, including metabolic, morphological, functional and structural changes. Some changes correlate with activation of p38 mitogen activated protein kinase (p38 MAPK). Another MAPK, extracellular signal-related kinase (ERK), is involved in PLT activation. The aim of this study was to compare the properties of platelets stored in plasma in the presence or absence of p38 and ERK MAPK inhibitors. Materials and Methods A single Trima apheresis platelet unit (n = 12) was aliquoted into five CLX storage bags. Two aliquots were continuously agitated with or without MAPK inhibitors. Two aliquots were subjected to 48 hours of interruption of agitation with or without MAPK inhibitors. One aliquot contained the same amount of solvent vehicle used to deliver the inhibitor. Platelets were stored at 20–24°C for 7 days and sampled on Days 1, 4, and 7 for 18 in vitro parameters. Results Inhibition of p38 MAPK by VX-702 leads to better maintenance of all platelet in vitro storage parameters including platelet mitochondrial function. Accelerated by interruption of agitation, the platelet storage lesion of units stored with VX-702 was diminished to that of platelets stored with continuous agitation. Inhibition of ERK MAPK did not ameliorate decrements in any in vitro platelet properties. Conclusion Signaling through p38 MAPK, but not ERK, is associated with platelet deterioration during storage.

Calcium is a key constituent for maintaining the in vitro properties of platelets suspended in the bicarbonate‐containing additive solution M‐sol with low plasma levels

BACKGROUND: Commercially available additive solutions (ASs) require 30% to 35% plasma for optimal storage of platelets (PLTs). PLTs suspended in M‐sol, a bicarbonate‐based experimental platelet additive solution (PAS), maintain in vitro PLT properties during storage with low levels of plasma (≤5%).

Thiazole orange, a DNA‐binding photosensitizer with flexible structure, can inactivate pathogens in red blood cell suspensions while maintaining red cell storage properties

BACKGROUND:  Development of a robust pathogen reduction system for red cells (RBCs) utilizing photosensitive dyes has been constrained by hemolysis, usually mediated by reactive oxygen species emanating from dye free in solution as well as dye bound to the RBC membrane. The RBC binding properties of thiazole orange (TO), a flexible nucleic acid intercalating cyanine dye that predominantly acts as a photosensitizer only when bound, were assessed along with its virucidal, bactericidal, and light‐induced hemolytic activities.

A rest period before agitation may improve some in vitro apheresis platelet parameters during storage.

BACKGROUND: Whole blood‐derived platelets (PLTs) prepared by the PLT‐rich plasma method are subjected to a recommended 1‐hour rest period after the second centrifugation to avoid excessive PLT activation. Different apheresis PLT preparation methods demonstrate different levels of PLT activation and ability to form macroscopic aggregates immediately after collection. PLT collections are lost on Day 1 of storage if aggregates are not dispersed. It is possible that a rest period may help to disperse PLT aggregates. It is not established whether apheresis PLTs require a rest period before agitation and what the length of this period should be.

Evaluation of in vitro storage properties of prestorage pooled whole blood–derived platelets suspended in 100 percent plasma and treated with amotosalen and long‐wavelength ultraviolet light

BACKGROUND: Amotosalen, a psoralen, has been utilized for photochemical treatment (PCT) of apheresis platelets (PLTs) and pooled buffy coat PLTs suspended in additive solution. In the United States, the source of many PLT transfusions is from whole blood–derived PLTs prepared by the PLT‐rich plasma (PRP) method. This study investigated the in vitro PLT properties of amotosalen‐PCT of leukoreduced pools of PLTs prepared by the PRP method and suspended in 100 percent plasma.

Mitochondrial dysfunction of platelets stored in first- and second-generation containers is, in part, associated with elevated carbon dioxide levels.

BACKGROUND: The gas permeability of platelet (PLT) storage bags influences the retention of in vitro PLT parameters during storage. The aim of this study was to evaluate mitochondrial function of PLTs stored in first‐ and second‐generation bags with different gas permeabilities.

Addition of sialidase or p38 MAPK inhibitors does not ameliorate decrements in platelet in vitro storage properties caused by 4 °C storage.

Bacterial proliferation is inhibited in platelets (PLTs) stored at refrigerated temperatures, but also dramatically decreases PLT in vivo survival. Recent studies have demonstrated that cold temperature (CT) stored PLTs secrete sialidases upon re‐warming, removing sialic acid from the PLT surface, which may be responsible for clustering of GPIbα and PLT clearance from circulation. In this study, the influence of a sialidase inhibitor or a p38 MAP kinase inhibitor was evaluated in units stored at 4 °C.