Pathogen inactivation in platelet concentrate storage : effects on quality and utilization

In transfusion medicine and blood banking, product quality and safety of patients are both essential. Blood transfusion is, in many instances, a lifesaving procedure; however, is not without risk. Blood products contain biological response modifiers (BRMs) that can induce febrile and allergic reactions and there is risk of donor/patient incompatibility, resulting in hemolytic transfusion reaction. Pathogen contamination of donor origin or due to collection and processing is another risk. The implementation of efficient viral screening has made blood transfusions safer, despite not addressing the risks from emerging pathogens or from bacterial contamination. For platelet concentrates (PCs) in particular, the standard storge conditions (room temperature) present an elevated risk of bacterial contamination and transfusion transmitted bacterial infection (TTBI) compared to other blood components, which are stored at subzero or refrigerated temperatures. Though the risk of TTBI can be minimized via the use of various screening assays, TTBI resulting in sepsis still occurs, with a high mortality rate. Therefore, methods have been developed to inactivate pathogens in blood products; such methods include photo or photochemical techniques, which influence the nucleic acids of pathogens and disable transcription. These methods have proven highly efficient in reducing the pathogenic load in blood products, namely PCs and plasma. As these methods have been approved through clinical trials and then implemented in routine use, indications of negative effects on blood products have emerged, specifically effects on platelet quality have been of concern. In response to the concern about reduced platelet quality, we investigated effect of pathogen inactivation (PI) with amotosalen and ultraviolet A (UVA) on the quality of stored platelets using a pool and split strategy and whole blood collected buffy coat (BC) platelet concentrates, with the aim of adding to the existing information. Multiple reports have suggested that micro RNA (miRNA) are important post transcription regulators in platelets, and there have been indications of altered miRNA profile due to pathogen inactivation (PI) methods. Therefore, we examined PI effects on 25 pre-selected miRNAs. Minimal influence was observed, with only 1 out of the 25 showing PI treatment-related down regulation. The release of BRMs from platelets into the storage media presents a potential risk of adverse events, as well as BRMs being indicators of platelet activation during storge. Monitoring the concentration of 36 proteins, we observed both reduction and increase of BRMs related to PI treatment. Additionally, PC utilization in national blood transfusion services (at the Blood Bank of Iceland) was analyzed pre- and post-PI implementation. We observed several PI treatment-related effects on both miRNA profiles and protein concentrations in the storage media, as well as elevated expression of markers of platelets storge lesion (PSL), though these effects did not translate to increased utilization or adverse events. We also observed increased product availability and more efficient stock management due to increased storge time, without an increase in outdated stock.Í blóðbankastarfsemi og við blóðinngjöf skipta gæði afurðar og öryggi sjúklings öllu máli. Í mörgum tilfellum er blóðinngjöf lífsbjargandi meðferð, en ekki laus við áhættu. Blóð inniheldur lífvirka þætti sem geta stuðlað að aukaverkunum eins og hækkun á líkamshita og ofnæmi, að auki er áhætta á blóðgjafa og blóðþega misræmi sem getur valdið niðurbroti á blóðfrumum. Sýking í blóðhluta sem getur átt uppruna frá blóðgjafa eða við vinnslu á blóðhlutanum er annar áhættuþáttur. Innleiðing veiru skimunar í blóðhlutum hefur aukið mikið á öryggi við blóðinngjöf, án þess þó koma í veg fyrir sýkingar vegna óþekktra sýkla eða bakteríu smits. Almennt er blóðflögu þykkni (BÞ) geymt á vöggu og við stofuhita sem eru kjöraðstæður fyrir vöxt baktería, og þess vegna er áhætta á slíku smiti margföld í tilfelli BÞ borið saman við aðra blóðhluta sem eru kældir eða frystir við geymslu. Hægt er að lágmarka áhættu á bakteríu mengun með margvíslegum skimunar aðferðum, en þrátt fyrir slíkar aðferðir eru tilfelli þar sem bakteríu mengað BÞ veldur alvarlegri blóðsýkingu með hárri tíðni dauðsfalla. Til að draga enn frekar úr og jafnvel koma alveg í veg fyrir bakteríu mengun i BÞ hafa verið þróaðar smit-hreinsunar (SH) aðferðir sem byggja ljósa eða ljósa og efnatækni sem hafa áhrif á kjarnsýrur í sýklum og koma í veg fyrir umritun. Þessar aðferðir hafa sannað sig í að draga úr magni sýkla í blóðhlutum, þá sérstaklega BÞ og blóðvökva. Á sama tíma og þessar aðferðir fengu samþykki byggt á klínískum tilraunum og voru innleiddar inn i almenna blóðbanka starfsemi, komu fram vísbendingar um neikvæð áhrif á gæði blóðhluta sérstaklega BÞ

The effect of Dlg7 overexpression and silencing on mouse embryonic stem cell differentiation

The genetic program controlling stem cell self-renewal and differentiation is yet to be elucidated although significant contributions have been made. Recently, in vitro and in vivo studies have identified several genetic regulatory programs such as various transcription factors, cell cycle inhibitors, genes implicated in chromosomal rearrangements, essential developmental proteins, and signalling pathways that have all been implicated in the process of stem cell self-renewal and differentiation. Dlg7, a novel cell cycle regulator gene, is expressed in stem cells, including haematopoietic stem cells (HSC), mesenchymal stem cells (MSC) and mouse embryonic stem cells (mESC). Dlg7 is expressed in human haematopoietic stem cells (CD34+CD38-) but much less expression was detected in haematopoietic progenitor cells (CD34+38+) or in fully mature blood cells. Dlg7 is expressed in many leukemic cell lines and in several tumours including bladder, colon and liver, while not being found in healthy adjacent normal tissue. In addition, it is a potential oncogenic target of Aurora-A, and is associated with invasiveness of hepatocellular carcinoma. The aim of this project was to study the role of Dlg7 in the differentiation of mESC with special emphases on haematopoiesis. We use lentiviral based vectors to silence and overexpress the Dlg7 gene in mESC. Transgenic mESC were differentiated to Embryo Bodies and haematopoietic colony forming units. Effects of genetic changes were monitored using a colony forming unit (CFU) assay, flow-cytometry and Q-PCR. Dlg7 overexpression and silencing significantly reduces the number of EBs that form in Primary differentiation media compared to scrambled control cell population. Of the EBs that formed a significant larger portion of EB from the scrambled control acquired hematopoietic morphology at later stage of differentiation compared to mESC with Dlg7 overexpression or silencing. BFU-E where in grater numbers with in the CFU population formed from cells with Dlg7 overexpression then in the scrambled control cells. We can however not say with full certenty that the effect of Dlg7 in hematopoiesis is a direct effect or rather a general effect in differentiation due to the role that Dlg7 plays in the cell cycle.Rannsóknarsjóður Rannsóknarmiðstöðvar Íslands (Rannís), Vísindasjóður Landspítala University Hospita

New strategies to understand platelet storage lesion

To access publisher's full text version of this article click on the hyperlink belowModern health care is dependent on the banking and transfusion of platelet concentrates. Platelets, however, can pose a problem for stock management at blood banks due to their limited storage time. In most countries, platelets can be stored from 3 to 7 days and due limited storage time up to 30% of all platelet concentrates are discarded without ever being used for clinical transfusion. The main reasons for this limited storage time are increased risk of bacterial contamination, due to the storage conditions at 22°C, and a formation of a condition termed platelet storage lesion (PSL) that decreases the quality of the platelets and makes them less efficient for clinical use as the storage prolongs. Increased understanding of PSL formation and how it can be combated is important to increase the quality of platelets during storage, in turn making them more efficient for clinical use. There are several methods used to detect formation of PSL, including analysing expression of surface markers on platelets using flow cytometry, analysing function of platelets using light transmission aggregometry and release of cytokines and growth factors using, for example ELISA. However, those methods focus more on studying the consequence of PSL instead of the cause of PSL. In recent years, several laboratories, including ours, have been using novel ways to further try to understand the formation of PSL. These include, for example analysing changes in proteomics, miRNA and metabolomics in platelets during storage. In this short overview, we will review how novel methods have been used to shed new lights on the formation of PSL

Protein Concentrations in Stored Pooled Platelet Concentrates Treated with Pathogen Inactivation by Amotosalen Plus Ultraviolet a Illumination

Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Platelet granules contain a diverse group of proteins. Upon activation and during storage, platelets release a number of proteins into the circulation or supernatant of stored platelet concentrate (PC). The aim of this work was to investigate the effect of pathogen inactivation (PI) on a selection of proteins released in stored platelets. Materials and Methods: PCs in platelet additive solution (PAS) were produced from whole blood donations using the buffy coat (BC) method. PCs in the treatment arm were pathogen inactivated with amotosalen and UVA, while PCs in the second arm were used as an untreated platelet control. Concentrations of 36 proteins were monitored in the PCs during storage. Results: The majority of proteins increased in concentration over the storage period. In addition, 10 of the 29 proteins that showed change had significantly different concentrations between the PI treatment and the control at one or more timepoints. A subset of six proteins displayed a PI-related drop in concentration. Conclusions: PI has limited effect on protein concentration stored PC supernatant. The protein’s changes related to PI treatment with elevated concentration implicate accelerated Platelet storage lesion (PSL); in contrast, there are potential novel benefits to PI related decrease in protein concentration that need further investigation.Peer reviewe