Laboratory of Cellular Hematology, Division of Hematology, Office of Blood Research and Review, Center for Biologics Evaluation and Research, United States Food and Drug Administration, 1401 Rockville Pike, Rockville, MD 20852, USA.
Clinical performance of human platelet (PLT) products processed or stored under novel conditions is difficult to predict based on in vitro studies alone. Recovery and survival of radiolabeled PLTs in human subjects are used as surrogate markers for PLT efficacy in development of new products. Such experiments pose some risk to the participants, can be a financial burden on the sponsor, and may stifle innovation and development of new PLT products. Animal models for in vivo recovery and survival of human PLTs are limited by rapid, immune-mediated clearance of human cells. The severe combined immunodeficient (SCID) mice allowed prolonged circulation of human PLTs and were used to detect differences in recovery and survival between chemically damaged, aged PLTs, or normal PLTs.
Human PLTs were transfused into SCID and wild-type (WT) mice, and the recoveries and survival times were detected in mouse whole blood by flow cytometry with an anti-human CD41-fluorescein isothiocyanate monoclonal antibody. Recoveries of damaged PLTs were compared to normal PLTs.
Recoveries were significantly shorter in WT than in SCID mice at 4 hours after transfusion (WT, 20.8 +/- 5.4%, n = 12; SCID, 63.8 +/- 8.4%, n = 10) and with a t((1/2)) estimate of 2 hours for WT and 7 hours for SCID mice. Human PLTs damaged either by chemical treatment or by improper storage exhibited decreased recoveries in SCID mice.
The SCID mouse model can detect differences between damaged and control human PLTs and could be useful in evaluating novel PLT collection, processing, and storage technologies that may impact PLT quality.
[Show abstract][Hide abstract] ABSTRACT: We previously reported that ultraviolet light B (UVB)-treated human platelets (hPLTs) can cause acute lung injury (ALI) in a two-event SCID mouse model in which the predisposing event was Lipopolysaccharide (LPS) injection and the second event was infusion of UVB-treated hPLTs. To delineate contributions of host mouse platelets (mPLTs) and neutrophils in the pathogenesis of ALI in this mouse model, we depleted mPLTs or neutrophils and measured hPLT accumulation in the lung. We also assessed lung injury by protein content in bronchoalveolar lavage fluid (BALF). LPS injection followed by infusion of UVB-treated hPLTs resulted in sequestration of both mPLTs and hPLTs in the lungs of SCID mice, although the numbers of neutrophils in the lung were not significantly different from the control group. Depletion of mouse neutrophils caused only a mild reduction in UVB-hPLTs accumulation in the lungs and a mild reduction in protein content in BALF. In comparison, depletion of mPLTs almost completely abolished hPLTs accumulation in the lung and significantly reduced protein content in BALF. UVB-treated hPLTs bound to host mPLTs, but did not bind to neutrophils in the lung. Aspirin treatment of hPLTs in vitro abolished hPLT accumulation in the lung and protected mice from lung injury. Our data indicate that host mPLTs accumulated in the lungs in response to an inflammatory challenge and subsequently mediated the attachment of transfused UVB-hPLTs. Neutrophils also recruited a small percentage of platelets to the lung. These findings may help develop therapeutic strategies for ALI which could potentially result from transfusion of UV illuminated platelets.
PLoS ONE 09/2012; 7(9):e44829. DOI:10.1371/journal.pone.0044829 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Retrospective studies on transfusion recipients suggested that transfusion of older red blood cells (RBCs) was associated with higher morbidity. Similar studies were also done on cardiac surgery patients who were placed on cardiac bypass pumps. It is possible that stored RBCs are more fragile and could be more easily damaged by these pumps, thus leading to additional morbidity.
Fresh and stored (42 days) RBCs, rejuvenated and nonrejuvenated, were compared in resistance to physical stress, induced by a roller pump, and osmotic fragility changes during physical stress to model RBCs going through cardiac bypass instruments. In addition, posttransfusion in vivo recovery was evaluated in an immunodeficient mouse model to minimize species differences between transfusion product and recipient.
Fresh RBCs were more resistant to both osmotic and physical stress than stored cells. After 2 hours of physical stress, the osmotic stress resistance of fresh cells declined and was the same as for stored cells. Rejuvenated fresh cells did not demonstrate a decline in osmotic resistance during the stress test and both fresh and stored cells had the same improved resistance to osmotic stress before and after the physical stress. Rejuvenation slightly improved recovery of fresh RBCs but almost doubled the recovery of stored cells in the mouse model.
Our studies suggest that rejuvenation improves roller pump-induced physical and osmotic stress resistance of stored RBCs.
[Show abstract][Hide abstract] ABSTRACT: Ultraviolet B (UVB) light has been used alone on platelet (PLT) transfusion products to prevent alloimmunization or with chemical sensitizers to reduce pathogens. Such processing can damage PLTs and potentiate their storage lesion. Transfusion-related acute lung injury (ALI) has occurred in patients whose underlying condition led to an inflamed endothelium and who were transfused with products that contained either HLA or HNA antibodies or biologic modifiers such as lipids or antigens from stored cells. Clinical trials of UV-treated PLTs in patients with thrombocytopenia generated controversy regarding association of these cells with respiratory distress. We evaluated whether UVB PLTs could mediate ALI in an animal model of ALI.
We used a two-event animal model where the sensitizing event was lipopolysaccharide (LPS) and the second event was infusion of human PLTs or UVB human PLTs (2.4 J/cm(2) ). Infused human PLTs were followed with whole animal imaging, lung histology, confocal microscopy, lung water, and changes in bronchoalveolar lavage fluid (BALF) related to ALI.
In LPS-treated mice UVB human PLTs accumulated in the lungs and were associated with ALI manifested by increased protein and white blood cells (WBCs) in BALF. Untreated human PLTs did not accumulate in the lungs or increase BALF protein or WBC counts.
We provide a proof of principle that UVB human PLTs can accumulate in lungs of LPS-primed animals and mediate ALI. PLTs exposed to high doses of UVB could potentially mediate similar effects in patients predisposed with sepsis or other causes of endothelial cell inflammation.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.