Andrew Myrup

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.

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%).

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.

Toward closed-system culture of blood origin endothelial cells.

BACKGROUND: Blood outgrowth endothelial cells (BOECs) are thought to arise from very rare progenitors that are present in the mononuclear fraction of marrow or peripheral blood. Recently, BOECs have been expanded from progenitors present in buffy coat into confluent monolayers on fibronectin‐ or collagen‐coated polystyrene surfaces. A method for sterile closed‐system culture of these cells has not been described, however. Here, efforts are described toward developing closed‐system culture of BOECs derived from progenitors present in a mononuclear apheresis unit by use of a cord blood filter, a sterile connection device, and a fibronectin‐coated polycarbonate cassette.

Influence of apheresis container size on the maintenance of platelet in vitro storage properties after a 30-h interruption of agitation

We have previously conducted studies investigating maintenance of apheresis platelet in vitro quality measures during storage under simulated shipping conditions in which agitation was interrupted. This study examines the effect of increasing bag surface area on the preservation of in vitro platelet properties during storage with continuous agitation and with a 30 h interruption of agitation. Apheresis platelets were collected in 100% plasma with the Amicus separator to provide two identical platelet products, each with approximately 4-5 x 10(11) platelets. After collection, the volume was divided equally between 1.0 and 1.3 L PL2410 containers. In an initial study, both products were continuously agitated. In a second study, both products were subjected to a single 30-h period of interrupted agitation between Days 2 and 3 of storage by placement in a standard shipping box at room temperature. In each study, units were assayed during storage for standard in vitro platelet quality measures. Platelets stored in the 1.3 L container maintained slightly greater mean pH during 7 day storage with either continuous agitation (n=6) or with a 30-h interruption of agitation (n=12) than those of similarly treated identical platelets stored in the 1.0 L container. Most noteworthy, in experiments with products stored in the 1.0 L container in which there was a large decrease in pH to levels <6.7 or <6.3 on days 5 or 7, respectively, the pH in the matched product stored in the 1.3 L container was substantially greater (0.17+/-06 and 0.37+/-0.09 pH units greater, n=4, respectively). Other measures showed either small differences or comparability of platelet in vitro parameters with storage in the two containers after an interruption of agitation.

Sterile isolation and cryopreservation of human adherent monocytes/macrophages from mononuclear cell apheresis preparations

There is evidence from animal and human study that suggests clinical use of monocytes/macrophages may be of benefit in wound healing, tissue regeneration, and cancer therapy. To facilitate further study, a method was developed for sterile isolation and cryopreservation of adherent monocyte/macrophages from mononuclear cell apheresis units collected from unstimulated normal human donors. Preparations contained approximately 1 × 108 total cells and were comprised of approximately 60% monocytes, 38% lymphocytes, and 2% granulocytes. Cells could be cryopreserved for up to 8 months and subsequently thawed and stored at 1–6°C for up to 4 hours with retention of viability and adequate phagocytic function. These cells can be used in clinical trials to determine their possible therapeutic benefit, e.g., whether administration of exogenously supplied cells improves the healing of chronic wounds or promotes the regeneration of transected nerves. (WOUND REP REG 2003;11:145–149)