Dirk de Korte

Effects of skin disinfection method, deviation bag, and bacterial screening on clinical safety of platelet transfusions in the Netherlands

BACKGROUND:  Bacterial contamination of blood products is a great hazard for development of fatal transfusion reactions. Bacterial screening of platelet concentrates (PC) by aerobic and anaerobic culturing (BacT/ALERT, bioMérieux) was introduced in the Netherlands in October 2001.

The effect of the transfusion of stored RBCs on intestinal microvascular oxygenation in the rat

BACKGROUND: Although it is known that the transfusion of stored RBCs does not always improve tissue O2 consumption under conditions of limited tissue oxygenation, the efficiency of O2 delivery to the microcirculation by stored RBCs has never been determined.

The mitochondrial membrane potential in human platelets: a sensitive parameter for platelet quality.

BACKGROUND:  Deterioration of platelet (PLT) quality during storage is accompanied by an increase in lactate production, indicating a decrease in mitochondrial function. In this study, the optimal conditions under which the fluorescent dye JC‐1 can be used to detect changes in mitochondrial function in PLTs were established.

Prolonged maintenance of 2,3-diphosphoglycerate acid and adenosine triphosphate in red blood cells during storage.

BACKGROUND: Current additive solutions (ASs) for red cells (RBCs) do not maintain a constant level of critical metabolites such as adenosine triphosphate (ATP) and 2,3‐diphosphoglycerate acid (2,3‐DPG) during cold storage. From the literature it is known that the intracellular pH is an important determinant of RBC metabolism. Therefore, a new, alkaline, AS was developed with the aim to allow cold storage of RBCs with stable product characteristics.

Determination of the degree of bacterialcontamination of whole‐blood collections using anautomated microbe‐detection system

BACKGROUND : The prevalence of bacterial contamination in whole‐blood collections, either with immediate sampling or sampling after overnight storage as whole blood at 20°C, is determined.

A novel flow cytometry-based platelet aggregation assay

The main function of platelets is to maintain normal hemostasis. Inefficient platelet production and/or defective platelet function results in bleeding disorders resulting from a wide range of genetic traits and acquired pathologies. Several platelet function tests have been developed for use in the clinic and in experimental animal models. In particular, platelet aggregation is routinely measured in an aggregometer, which requires normal platelet counts and significant blood sample volumes. For this reason, the analysis of thrombocytopenic patients, infants, and animal models is problematic. We have developed a novel flow cytometry test of platelet aggregation, in which 10- to 25-fold lower platelet counts or sample volumes can be used, either of platelet-rich plasma or whole blood from human subjects or mice. This setup can be applied to test in small assay volumes the influence of a variety of stimuli, drugs, and plasma factors, such as antibodies, on platelet aggregation. The presented principle stands as a novel promising tool, which allows analysis of platelet aggregation in thrombocytopenic patients or infants, and facilitates studies in platelets obtained from experimental animal models without the need of special devices but a flow cytometer.

Development of blood transfusion product pathogen reduction treatments: A review of methods, current applications and demands

Transfusion-transmitted infections (TTI) have been greatly reduced in numbers due to the strict donor selection and screening procedures, i.e. the availability of technologies to test donors for endemic infections, and routine vigilance of regulatory authorities in every step of the blood supply chain (collection, processing and storage). However, safety improvement is still a matter of concern because infection zero-risk in transfusion medicine is non-existent. Alternatives are required to assure the safety of the transfusion product and to provide a substitution to systematic blood screening tests, especially in less-developed countries or at the war-field. Furthermore, the increasing mobility of the population due to traveling poses a new challenge in the endemic screening tests routinely used, because non-endemic pathogens might emerge in a specific population. Pathogen reduction treatments sum a plethora of active approaches to eliminate or reduce potential threatening pathogen load from blood transfusion products. Despite the success of pathogen reduction treatments applied to plasma products, there is still a long way to develop and deploy pathogen reduction treatments to cellular transfusion products (such as platelets, RBCs or even to whole blood) and there is divergence on its acceptance worldwide. While the use of pathogen reduction treatments in platelets is performed routinely in a fair number of European blood banks, most of these treatments are not (or just) licensed in the USA or elsewhere in the world. The development of pathogen reduction treatments for RBC and whole blood is still in its infancy and under clinical trials. In this review, we discuss the available and emerging pathogen reduction treatments and their advantages and disadvantages. Furthermore, we highlight the importance of characterizing standard transfusion products with current and emerging approaches (OMICS) and clinical outcome, and integrating this information on a database, thinking on the benefits it might bring in the future toward personalized transfusion therapies.

UV-C irradiation disrupts platelet surface disulfide bonds and activates the platelet integrin alphaIIbbeta3

UV-C irradiation has been shown to be effective for pathogen reduction in platelet concentrates, but preliminary work indicated that UV-C irradiation of platelets can induce platelet aggregation. In this study, the mechanism underlying this phenomenon was investigated. Irradiation of platelets with UV-C light (1500 J/m(2)) caused platelet aggregation, which was dependent on integrin alphaIIbbeta3 activation (GPIIb/IIIa). This activation occurred despite treatment with several signal transduction inhibitors known to block platelet activation. UV-C also induced activation of recombinant alphaIIbbeta3 in Chinese hamster ovary (CHO) cells, an environment in which physiologic agonists fail to activate. Activation of alphaIIbbeta3 requires talin binding to the beta3 tail, yet alphaIIbbeta3-Delta724 (lacking the talin binding site) was activated by UV-C irradiation, excluding a requirement for talin binding. The UV-C effect appears to be general in that beta(1) and beta(2) integrins are also activated by UV-C. To explain these findings, we investigated the possibility of UV-C-induced photolysis of disulfide bonds, in analogy with the activating effect of reducing agents on integrins. Indeed, UV-C induced a marked increase in free thiol groups in platelet surface proteins including alphaIIbbeta3. Thus, UV-C appears to activate alphaIIbbeta3 not by affecting intracellular signal transduction, but by reduction of disulfide bonds regulating integrin conformation.

Evaluation of platelet mitochondria integrity after treatment with Mirasol pathogen reduction technology.

BACKGROUND: Previous studies showed that Mirasol (Navigant Biotechnologies, Inc.) pathogen reduction technology (PRT) treatment resulted in an increase in platelet (PLT) glucose consumption and lactate production rates and decrease in pH in media during PLT storage. Increased glycolytic flux could result from damage to mitochondria and/or increased ATP consumption.

Influence of pH on stored human platelets.

BACKGROUND: During storage at room temperature, platelets (PLTs) undergo several changes, a process known as PLT storage lesion. The pH is one of the variables changing and has been suggested to be a good surrogate marker for the quality of PLT concentrates. It is unknown whether the pH decrease as such induces the PLT storage lesion or that the deterioration of the PLTs results in the pH decrease. In this study, the responses of PLTs to applied pH values were investigated.