Proteomic analysis of platelets treated with gamma irradiation versus a commercial photochemical pathogen reduction technology

Universal irradiation of platelets: Does irradiation affect the quality, effectiveness, and safety of platelets for transfusion?

We aimed to identify any detrimental effects on platelet quality and clinical effectiveness, of irradiated platelets compared to non-irradiated platelets for transfusion. The review was conducted in accordance with PRISMA guidelines. The protocol was prospectively registered on PROSPERO [CRD42023441930]. Our search identified 3002 references, of which we included 44 studies. Forty-one were in vitro only studies, two studies were in healthy volunteers, and one study reported clinical outcomes in thrombocytopenic patients. X-ray was used exclusively in three studies, and alongside gamma irradiation in one study. Two studies did not report the source of irradiation. The remaining 38 studies used gamma irradiation only. We assessed risk of bias (ROB) for studies reporting clinical and in vivo outcomes using ROB 2.0 (3 studies). We adapted a ROB tool designed for animal studies to assess ROB for the studies reporting in vitro outcomes (43 studies). We assessed the certainty of the evidence for the eight outcomes deemed most important to assess platelet quality and clinical effectiveness (where day 0 is the day of the blood draw). Overall, gamma irradiation has little to no effect on most markers of platelet quality and effectiveness. Where there is evidence of detriment from irradiation, differences are small in vitro, and are unlikely to affect clinical outcomes following transfusion. However, the evidence base is limited. Only half the studies could be included in any analysis. There is very limited evidence for x-ray as a source of irradiation and, given the potential benefits of using x-ray over gamma irradiation (ease of use and safety requirements), we would welcome further research comparing x-ray to gamma, and x-ray to a non-irradiated control.

Expanding applications of allogeneic platelets, platelet lysates, and platelet extracellular vesicles in cell therapy, regenerative medicine, and targeted drug delivery

Platelets are small anucleated blood cells primarily known for their vital hemostatic role. Allogeneic platelet concentrates (PCs) collected from healthy donors are an essential cellular product transfused by hospitals to control or prevent bleeding in patients affected by thrombocytopenia or platelet dysfunctions. Platelets fulfill additional essential functions in innate and adaptive immunity and inflammation, as well as in wound-healing and tissue-repair mechanisms. Platelets contain mitochondria, lysosomes, dense granules, and alpha-granules, which collectively are a remarkable reservoir of multiple trophic factors, enzymes, and signaling molecules. In addition, platelets are prone to release in the blood circulation a unique set of extracellular vesicles (p-EVs), which carry a rich biomolecular cargo influential in cell-cell communications. The exceptional functional roles played by platelets and p-EVs explain the recent interest in exploring the use of allogeneic PCs as source material to develop new biotherapies that could address needs in cell therapy, regenerative medicine, and targeted drug delivery. Pooled human platelet lysates (HPLs) can be produced from allogeneic PCs that have reached their expiration date and are no longer suitable for transfusion but remain valuable source materials for other applications. These HPLs can substitute for fetal bovine serum as a clinical grade xeno-free supplement of growth media used in the in vitro expansion of human cells for transplantation purposes. The use of expired allogeneic platelet concentrates has opened the way for small-pool or large-pool allogeneic HPLs and HPL-derived p-EVs as biotherapy for ocular surface disorders, wound care and, potentially, neurodegenerative diseases, osteoarthritis, and others. Additionally, allogeneic platelets are now seen as a readily available source of cells and EVs that can be exploited for targeted drug delivery vehicles. This article aims to offer an in-depth update on emerging translational applications of allogeneic platelet biotherapies while also highlighting their advantages and limitations as a clinical modality in regenerative medicine and cell therapies.

Gamma irradiation induces a pro-apoptotic state in longer stored platelets, without progressing to an overt apoptosis by day 7 of storage

BACKGROUND

Although gamma-irradiation to platelet products is a standard method to prevent the risk of TA-GVHD in vulnerable recipients, it induces some proteomic and redox changes, of which irradiation-induced ROS increments may potentiate platelet mitochondrial dysfunction. However, whether these changes cause platelet apoptosis, or affect their viability during storage, is the main subject of this study.

METHODS

PLT-rich plasma PC was split into two bags, one kept as control while other was subjected to gamma-irradiation. Within 7-days storage, cytosolic and mitochondrial levels of cytochrome c and pro-apoptotic molecules of Bak and Bax were evaluated by western-blotting. Intraplatelet active caspase (using FAM-DEVD-FMK) and PS-exposure were detected by flowcytometry. Caspase activity in platelet lysate was also confirmed by immunofluorescence detection of Caspase-3/7 Substrate N-Ac-DEVD-N'-MC-R110 while platelet viability was evaluated with MTT assays.

RESULTS

Cytosolic cytochrome c gradually increased while its mitochondrial content steadily declined during 7 days of storage. In a contrary trend, reverse patterns were observed for Bak and Bax expressions. Gamma-irradiated platelets showed higher release of mitochondrial cytochrome c that reflected by higher cytosolic cytochrome c levels on day 7 of storage. Concurrently mitochondrial pro-apoptotic Bak and Bax proteins increased on day 7 in irradiated products. However, gamma-irradiation didn't significantly increase caspase activity or PS-exposure, nor did it decrease platelet viability.

CONCLUSION

Here, consistent with studies on "gamma-irradiation-induced oxidative stress", we showed that gamma-ray also increases platelet pro-apoptotic signals during storage, although not strongly enough to affect platelet viability by overt apoptosis induction. Conclusively, whether supplementing ROS scavengers or antioxidants to irradiated platelets can improve their quality during storage may be of interest for future research.

Antimicrobial 405 nm violet-blue light treatment of ex vivo human platelets leads to mitochondrial metabolic reprogramming and potential alteration of Phospho-proteome

Continued efforts to reduce the risk of transfusion-transmitted infections (TTIs) through blood and blood components led to the development of ultraviolet (UV) light irradiation technologies known as pathogen reduction technologies (PRT) to enhance blood safety. While these PRTs demonstrate germicidal efficiency, it is generally accepted that these photoinactivation techniques have limitations as they employ treatment conditions shown to compromise the quality of the blood components. During ex vivo storage, platelets having mitochondria for energy production suffer most from the consequences of UV irradiation. Recently, application of visible violet-blue light in the 400-470 nm wavelength range has been identified as a relatively more compatible alternative to UV light. Hence, in this report, we evaluated 405 nm light-treated platelets to assess alterations in energy utilization by measuring different mitochondrial bioenergetic parameters, glycolytic flux, and reactive oxygen species (ROS). Furthermore, we employed untargeted data-independent acquisition mass spectrometry to characterize platelet proteomic differences in protein regulation after the light treatment. Overall, our analyses demonstrate that ex vivo treatment of human platelets with antimicrobial 405 nm violet-blue light leads to mitochondrial metabolic reprogramming to survive the treatment, and alters a fraction of platelet proteome.

Pathogen Reduction Technologies and Their Impact on Metabolic and Functional Properties of Treated Platelet Concentrates: A Systematic Review

Pathogen reduction technologies (PRTs) such as Mirasol and Intercept were developed to eliminate transfusion-transmitted infections. The impact of PRTs on platelet function during the storage period, their effect on platelet storage lesions, and the optimal storage duration following PRTs have not been clearly defined. The aim of this study was to systematically review the existing literature and investigate the impact of PRTs on functional alterations of PRT-treated platelets during the storage period. The authors identified 68 studies suitable to be included in this review. Despite the high heterogeneity in the literature, the results of the published studies indicate that PRTs may increase platelet metabolic activity, accelerate cell apoptosis, and enhance platelet activation, which can subsequently lead to a late exhaustion of activation potential and reduced aggregation response. However, these effects have a minor impact on platelet function during the early storage period and become more prominent beyond the fifth day of the storage period. Large in vivo trials are required to evaluate the effectiveness of PRT-treated platelets during the storage period and investigate whether their storage can be safely extended to more than 5 days, and up to the traditional 7-day storage period.

INTERCEPT Pathogen Reduction in Platelet Concentrates, in Contrast to Gamma Irradiation, Induces the Formation of trans-Arachidonic Acids and Affects Eicosanoid Release during Storage

Pathogen inactivation techniques for blood products have been implemented to optimize clinically safe blood components supply. The INTERCEPT system uses amotosalen together with ultraviolet light wavelength A (UVA) irradiation. Irradiation-induced inactivation of nucleic acids may actually be accompanied by modifications of chemically reactive polyunsaturated fatty acids known to be important mediators of platelet functions. Thus, here, we investigated eicosanoids and the related fatty acids released upon treatment and during storage of platelet concentrates for 7 days, complemented by the analysis of functional and metabolic consequences of these treatments. Metabolic and functional issues like glucose consumption, lactate formation, platelet aggregation, and clot firmness hardly differed between the two treatment groups. In contrast to gamma irradiation, here, we demonstrated that INTERCEPT treatment immediately caused new formation of trans-arachidonic acid isoforms, while 11-hydroxyeicosatetraenoic acid (11-HETE) and 15-HETE were increased and two hydroperoxyoctadecadienoic acid (HpODE) isoforms decreased. During further storage, these alterations remained stable, while the release of 12-lipoxygenase (12-LOX) products such as 12-HETE and 12-hydroxyeicosapentaenoic acid (12-HEPE) was further attenuated. In vitro synthesis of trans-arachidonic acid isoforms suggested that thiol radicals formed by UVA treatment may be responsible for the INTERCEPT-specific effects observed in platelet concentrates. It is reasonable to assume that UVA-induced molecules may have specific biological effects which need to be further investigated.

Gamma and X-ray irradiation do not affect the in vitro quality of refrigerated apheresis platelets in platelet additive solution (PAS-E)

BACKGROUND

Platelet refrigeration (cold storage) provides the advantages of an extended shelf life and reduces the risk of bacterial growth, compared to platelets stored at room temperature (RT). However, processing modifications, such as irradiation, may further improve the safety and/or alter the quality of cold-stored platelets. Platelet components are irradiated to prevent transfusion-associated graft versus host disease (TA-GvHD) in high-risk patients; and while irradiation has little effect on the quality of RT-stored platelet components, there is no data assessing the effect irradiation has following cold storage.

STUDY DESIGN AND METHODS

Triple-dose apheresis platelets were collected in 40% plasma/60% PAS-E, using the TRIMA apheresis platform, and refrigerated (2-6°C) within 8 h of collection. On day 2, one of each component was gamma or X-ray irradiated or remained non-irradiated. Platelets were tested over 21 days.

RESULTS

The platelet concentration decreased by approximately 20% in all groups during 21 days of storage (p > .05). Irradiation (gamma or X-ray) did not affect platelet metabolism, and the pH was maintained above the minimum specification (>6.4) for 21 days. The surface phenotype and the composition of the supernatant was similar in non-irradiated and irradiated platelets, regardless of the source of radiation. Functional responses (aggregation and clot formation) were not affected by irradiation.

DISCUSSION

Gamma and X-ray irradiation do not affect the in vitro quality of platelet components stored in the cold for up to 21 days. This demonstrates the acceptability of irradiating cold-stored platelets, which has the potential to improve their safety for at-risk patient cohorts.

Impact of different pathogen reduction technologies on the biochemistry, function, and clinical effectiveness of platelet concentrates: An updated view during a pandemic

Standard platelet concentrates (PCs) stored at 22°C have a limited shelf life of 5 days. Because of the storage temperature, bacterial contamination of PCs can result in life‐threatening infections in transfused patients. The potential of blood components to cause infections through contaminating pathogens or transmitting blood‐borne diseases has always been a concern. The current safety practice to prevent pathogen transmission through blood transfusion starts with a stringent screening of donors and regulated testing of blood samples to ensure that known infections cannot reach transfusion products. Pathogen reduction technologies (PRTs), initially implemented to ensure the safety of plasma products, have been adapted to treat platelet products. In addition to reducing bacterial contamination, PRT applied to PCs can extend their shelf life up to 7 days, alleviating the impact of their shortage, while providing an additional safety layer against emerging blood‐borne infectious diseases. While a deleterious action of PRTs in quantitative and qualitative aspects of plasma is accepted, the impact of PRTs on the quality, function, and clinical efficacy of PCs has been under constant examination. The potential of PRTs to prevent the possibility of new emerging diseases to reach cellular blood components has been considered more hypothetical than real. In 2019, a coronavirus‐related disease (COVID‐19) became a pandemic. This episode should help when reconsidering the possibility of future blood transmissible threats. The following text intends to evaluate the impact of different PRTs on the quality, function, and clinical effectiveness of platelets within the perspective of a developing pandemic.

Irradiation of platelets in Transfusion Medicine: risk and benefit judgments

Irradiation of platelet products is generally used to prevent transfusion-associated graft-versus-host disease (TA-GvHD) as well as transfusion-transmitted infections. As an essential prerequisite, gamma-irradiation of blood products prior to transfusion is required in patients who may develop TA-GVHD. Most studies suggest that gamma irradiation has no significant effect on the quality of platelet products; however, more recent studies have shown that the oxidative effects of gamma irradiation can lead to the induction of platelet storage lesion (PSL) and to some extent reduce the efficiency of transfused platelets. As the second widely used irradiation technique, UV-illumination was primarily introduced to reduce the growth of infectious agents during platelet storage, with the advantage that this method can also prevent TA-GvHD. However, the induction of oxidative conditions and platelet pre-activation that lead to PSL is more pronounced after UV-based methods of pathogen reduction. Since these lesions are large enough to clearly affect the post-transfusion platelet recovery and survival, more studies are needed to improve the safety and effectiveness of pathogen reduction technologies (PRTs). Therefore, pointing to other benefits of PRTs, such as preventing TA-GvHD or prolonging the shelf life of products by eliminating the possibility of pathogen growth during storage, does not yet seem to justify their widespread use due to above-mentioned effects. Even for gamma-irradiated platelets, some researchers have suggested that due to decreased 1-hour post-transfusion increments and increased risk of platelet refractoriness, their use should be limited to the patients who may develop TA-GVHD. It is noteworthy that due to the effect of X-rays in preventing TA-GvHD, some recent studies are underway to examine its effects on the quality and effectiveness of platelet products and determine whether X-rays can be used as a more appropriate and cost-effective alternative to gamma radiation. The review presented here provides a detailed description about irradiation-based technologies for platelet products, including their applications, mechanistic features, advantages, and disadvantages.

The in vitro quality of X-irradiated platelet components in PAS-E is equivalent to gamma-irradiated components

BACKGROUND

Blood components are irradiated to inactivate lymphocytes in an effort to prevent transfusion-associated graft versus host disease. Although gamma irradiators are commonly used, they are subjected to rigorous health, safety, and compliance regulations, compared with X-irradiators which have the advantage of only emitting radiation while the machine is switched on. While the effects of gamma irradiation on platelet components are well known, there is little or no data comparing the effects of X- and gamma-irradiation on the quality of these components. Therefore, this study examined the in vitro quality of platelet components (pooled and apheresis) following X- or gamma-irradiation.

STUDY DESIGN AND METHODS

Whole-blood-derived (pooled) and apheresis platelet components in platelet additive solution (n = 20 pairs for each type) were irradiated (X vs. gamma). In vitro platelet quality was tested prior to irradiation (day 1) and subsequently on days 2, 5, and 7. Non-irradiated components were tested on day 5 in parallel as reference controls. Metabolic parameters, surface expression of glycoproteins and activation markers (CD62P and annexin-V binding), and agonist-induced aggregation were measured.

RESULTS

All components met Council of Europe specifications. There were no statistical differences in any in vitro quality measurements between X- and gamma-irradiated pooled or apheresis platelet components.

CONCLUSION

X- and gamma-irradiation have similar effects on the in vitro quality of stored blood components, indicating that either technology represents a suitable option for irradiation of platelet components.

Platelet transfusion practice and related transfusion reactions in a large teaching hospital

BACKGROUND

Platelet transfusion practice varies widely since many aspects of platelet concentrate (PC) use have not been definitively determined. The objectives of this retrospective study were to present platelet transfusion practice and evaluate PC and patient characteristics, as well as their association with transfusion reaction (TR) rate.

MATERIAL AND METHODS

Platelet transfusions over a 5-year period were analysed regarding PC characteristics (the ABO and RhD compatibility, product type, and storage duration), patient characteristics (most responsible diagnosis, age, and gender), and TR type.

RESULTS

A total of 46,351 PCs were transfused: 76.4% whole blood-derived (WBD) and 23.6% single donor apheresis (SDA). Three thousand seven hundred seventy-six patients received platelet transfusions: 24.7% paediatric and 75.3% adult patients, 79.6% outpatients and 20.4% inpatients. As much as 63.1% of all transfused PCs were fresh (stored for≤3 days), 98.0% ABO-identical, and 87.3% of all PCs given to RhD- patients were RhD-. PCs were mainly transfused to haemato-oncology (76.8%) and cardiovascular surgery patients (6.5%). Overall, 84 (0.18%) TRs were reported, with allergic TRs (ATRs) being the most common. Although PC ABO compatibility and storage duration, as well as patient age and gender, showed differences in TR rate, only the use of PCs in platelet additive solution (PAS) showed a statistically significant reduction of TRs (P<0.001).

CONCLUSION

Transfusion practice at the University Hospital Centre Zagreb resulted in almost all patients receiving ABO and RhD identical PCs, and most of them were fresh PCs. The most important factor affecting the incidence of TRs was platelet storage solution. The use of PAS effectively reduced the rate of TRs, particularly allergic TRs.

Extracellular vesicles in the transfusion medicine field: The potential of proteomics

In transfusion centres, blood components are divided and stored following specific guidelines. The storage temperature and time vary among the blood cells but all of them release extracellular vesicles (EVs) under blood bank conditions. The clinical impact of such vesicles in blood components for transfusion is an object of debate, but should be considered and is being investigated. In this context, proteomics is an excellent tool to study the cargo and composition of EVs derived from red blood cells and platelets, since such vesicles are enriched in lipids and proteins. The development of quantitative mass spectrometry techniques and the evolution of bioinformatics have allowed the identification of novel EVs biomarkers for different diseases. In this context, the application of high coverage proteomic tools to the analysis of EVs in the transfusion medicine field would provide information about storage lesions and possible transfusion adverse reactions. This viewpoint article approaches the potential of proteomics to investigate the impact of EVs in blood bank transfusion components, especially red blood cells and platelets.

Sulfenylome analysis of pathogen-inactivated platelets reveals the presence of cysteine oxidation in integrin signaling pathway and cytoskeleton regulation

Essentials Cysteine oxidation to sulfenic acid plays a key role in redox regulation and signal transduction. Platelet sulfenylome was studied by quantitative proteomics in pathogen inactivated platelets. One hundred and seventy-four sulfenylated proteins were identified in resting platelets. Pathogen inactivation oxidized integrin βIII, which could activate the mitogen-activated protein kinases pathway. ABSTRACT: Background Cysteine-containing protein modifications are involved in numerous biological processes such redox regulation or signal transduction. During the preparation and storage of platelet concentrates, cell functions and protein regulations are impacted. In spite of several proteomic investigations, the platelet sulfenylome, ie, the proteins containing cysteine residues (R-SH) oxidized to sulfenic acid (R-SOH), has not been characterized. Methods A dimedone-based sulfenic acid tagging and enrichment coupled to a mass spectrometry identification workflow was developed to identify and quantify the sulfenic acid-containing proteins in platelet concentrates treated or not with an amotosalen/ultraviolet A (UVA) pathogen inactivation technique. Results One hundred and seventy-four sulfenylated proteins were identified belonging mainly to the integrin signal pathway and cytoskeletal regulation by Rho GTPase. The impact on pathogen inactivated platelet concentrates was weak compared to untreated ones where three sulfenylated proteins (myosin heavy chain 9, integrin βIII, and transgelin 2) were significantly affected by amotosalen/UVA treatment. Of particular interest, the reported oxidation of cysteine residues in integrin βIII is known to activate the receptor αIIbβIII. Following the pathogen inactivation, it might trigger the phosphorylation of p38MAPK and explain the lesions reported in the literature. Moreover, procaspase activating compound-1 (PAC-1) binding assays on platelet activation showed an increased response to adenosine diphosphate exacerbated by the tagging of proteins with dimedone. This result corroborates the hypothesis of an oxidation-triggered activation of αIIbβIII by the pathogen inactivation treatment. Conclusions The present work completes missing information on the platelet proteome and provides new insights on the effect of pathogen inactivation linked to integrin signaling and cytoskeleton regulation.

The effect of gamma irradiation on platelet redox state during storage

BACKGROUND

As a method with insignificant adverse effects on in vitro quality of platelet concentrates (PCs), gamma irradiation is applied to abrogate the risk of transfusion-associated graft-vs-host disease in vulnerable recipients. However, there is some evidence of lower posttransfusion responses and proteomic alterations in gamma-irradiated platelets (PLTs), which raises some questions about their quality, safety, and efficacy. Since reactive oxygen species (ROS) are considered as markers of PLT storage lesion (PSL), the study presented here investigated oxidant state in gamma-irradiated PCs.

STUDY DESIGN AND METHODS

PLT-rich plasma PC was split into two bags, one kept as control while other was subjected to gamma irradiation. Within 7 days of storage, the levels of intra-PLT superoxide, H₂ O₂ , mitochondrial ROS, P-selectin expression, and phosphatidylserine (PS) exposure were detected by flow cytometry while intracellular reduced glutathione (GSH), glucose concentration, and lactate dehydrogenase (LDH) activity were measured by enzymocolorimetric method.

RESULTS

GSH decreased, while ROS generation and LDH activity increased, during storage. Gamma irradiation significantly attenuated GSH whereas increased ROS generation in earlier and later stages of storage associated with either P-selectin or PS exposure increments.

CONCLUSION

Gamma irradiation can significantly increase cytosolic ROS generation in two distinct phases, one upon irradiation and another later in longer-stored PCs. While earlier ROS influx seems to be governed by direct effect of irradiation, the second phase of oxidant stress is presumably due to the storage-dependent PLT activation. Intriguingly, these observations were also in line with early P-selectin increments and increased PS exposure in longer-stored PLTs. Given the mutual link between ROS generation and PLT activation, further investigation is required to explore the effect of gamma irradiation on the induction of PSL.

Metabolic phenotypes of standard and cold-stored platelets

BACKGROUND

Conventional platelet (PLT) storage at room temperature under continuous agitation results in a limited shelf life (5 days) and an increased risk of bacterial contamination. However, both of these aspects can be ameliorated by cold storage. Preliminary work has suggested that PLTs can be cold stored for up to 3 weeks, while preserving their metabolic activity longer than in PLTs stored at room temperature. As such, in the present study, we hypothesized that the metabolic phenotypes of PLTs stored at 4°C for 3 weeks could be comparable to that of room temperature-stored PLTs at 22°C for 5 days.

STUDY DESIGN AND METHODS

Metabolomics analyses were performed on nine apheresis PLT concentrates stored either at room temperature (22°C) for 5 days or refrigerated conditions (4°C) for up to 3 weeks.

RESULTS

Refrigeration did not impact the rate of decline in glutamine or the intracellular levels of Krebs cycle metabolites upstream to fumarate and malate. It did, however, decrease oxidant stress (to glutathione and purines) and slowed down the activation of the pentose phosphate pathway, glycolysis, and fatty acid metabolism (acyl-carnitines).

CONCLUSION

The overall metabolic phenotypes of 4°C PLTs at Storage Day 10 are comparable to PLTs stored at 22°C at the end of their 5-day shelf life, while additional changes in glycolysis, purine, and fatty acid metabolism are noted by Day 21.

Estimation of the number of blood donors during the COVID-19 incubation period across China and analysis of prevention and control measures for blood transfusion transmission

BACKGROUND

The aim of this study was to estimate the number of blood donors during the COVID‐19 incubation period across China.

STUDY DESIGN AND METHODS

In this study, we developed a predictive model to estimate the number of blood donors during the COVID‐19 incubation period among 34 provincial regions in China. Our main assumption was that blood donors of all ages in different regions have a stable blood donation intention and the same infection risk.

RESULTS

First, we estimated the number of blood donors during the COVID‐19 incubation period in Wuhan city, Hubei Province, and China, from December 31, 2019 to March 17, 2020. Second, we compared the number of blood donors during the COVID‐19 incubation period in all provinces across China. In addition, we found that if all RBCs, plasma, and cryoprecipitation were stored in isolation until the 14th day, the potential risk of SARS‐CoV‐2 transmission through blood transfusion was reduced by at least 65.77% after the blood donor safely passed the COVID‐19 incubation period. Moreover, if the detection of SARS‐CoV‐2 RNA was carried out on all platelets, the potential risk would be reduced by 77.48%.

CONCLUSIONS

Although the risk is low, with the rapid spread of the COVID‐19 and the appearance of alarmingly high infectivity and a high fatality rate, appropriate measures should be taken by health departments to ensure the safety of clinical blood.

Proteomic analysis of extracellular vesicles derived from platelet concentrates treated with Mirasol® identifies biomarkers of platelet storage lesion

In blood banks, platelets are stored until 7 days after a pathogen reduction technology (PRT) treatment, Mirasol® (vitamin B₂ plus UVB light) in the present case. The storage time under these conditions may have an impact on platelets and their releasate leading to potential adverse reactions following transfusion to patients. The aim of this study was to analyze the proteome of extracellular vesicles generated by platelets at different storage days (2 and 7) to gain deeper information on the platelet concentrates state at those moments. EVs were isolated by a centrifugation-based approach and characterized by dynamic light scattering and transmission electron microscopy. Proteomic analysis was by LC-MS/MS and quantification by SWATH. In this way, 151 proteins were found up-regulated at day 7 of storage. This group includes CCL5 and Platelet Factor 4, chemokines with power to attract neutrophils and monocytes, which could generate transfusion adverse reactions. In addition, other glycoproteins and platelet activation markers were also found elevated at day 7. Proteins related to glycolysis and lactate production were found altered with high fold changes, showing a deregulation of platelet metabolism at day 7. The obtained results provide novel information about possible effects of platelet-derived EVs on transfusion adverse reactions. SIGNIFICANCE: We performed the first proteomic analysis of extracellular vesicles derived from platelets upon storage at different time points on blood bank conditions after Mirasol® treatment. We identified a high number of proteins related to platelet activation and platelet storage lesion that could have a role in possible transfusion adverse reactions.

The long and winding road to pathogen reduction of platelets, red blood cells and whole blood

Pathogen reduction technologies (PRTs) have been developed to further reduce the current very low risks of acquiring transfusion-transmitted infections and promptly respond to emerging infectious threats. An entire portfolio of PRTs suitable for all blood components is not available, but the field is steadily progressing. While PRTs for plasma have been used for many years, PRTs for platelets, red blood cells (RBC) and whole blood (WB) were developed more slowly, due to difficulties in preserving cell functions during storage. Two commercial platelet PRTs use ultra violet (UV) A and UVB light in the presence of amotosalen or riboflavin to inactivate pathogens' nucleic acids, while a third experimental PRT uses UVC light only. Two PRTs for WB and RBC have been tested in experimental clinical trials with storage limited to 21 or 35 days, due to unacceptably high RBC storage lesion beyond these time limits. This review summarizes pre-clinical investigations and selected outcomes from clinical trials using the above PRTs. Further studies are warranted to decrease cell storage lesions after PRT treatment and to test PRTs in different medical and surgical conditions. Affordability remains a major administrative obstacle to PRT use, particularly so in geographical regions with higher risks of transfusion-transmissible infections.

Irreversible oxidations of platelet proteins after riboflavin-UVB pathogen inactivation

Pathogen inactivation technologies are known to alter in vitro phenotype and functional properties of platelets. Because pathogen inactivation generates reactive oxygen species, oxidative stress is considered as one of the plausible cause at the origin of the platelet storage lesion acceleration after treatment. To date proteomics has been used to document the protein variations to picture out the impact. Here, platelet concentrates were prepared from buffy-coats in Intersol additive solution, leukoreduced and pathogen inactivated using a riboflavin/UVB treatment. At day 2 of storage the platelet proteomes of control (untreated) and treated platelet concentrates were investigated against the site specific oxidation by liquid chromatography coupled to tandem mass spectrometry in a shotgun experiment. The shotgun approach detected 9350 peptides (and 2534 proteins) of which 1714 were oxidized. Eighteen peptides were found exclusively oxidized in treated platelets whereas 3 peptides were only found oxidized in control. The present data evidenced an interference with several proteins involved in platelet aggregation and platelet shape change (such as talin and vinculin).

Ultraviolet-Based Pathogen Inactivation Systems: Untangling the Molecular Targets Activated in Platelets

Transfusions of platelets are an important cornerstone of medicine; however, recipients may be subject to risk of adverse events associated with the potential transmission of pathogens, especially bacteria. Pathogen inactivation (PI) technologies based on ultraviolet illumination have been developed in the last decades to mitigate this risk. This review discusses studies of platelet concentrates treated with the current generation of PI technologies to assess their impact on quality, PI capacity, safety, and clinical efficacy. Improved safety seems to come with the cost of reduced platelet functionality, and hence transfusion efficacy. In order to understand these negative impacts in more detail, several molecular analyses have identified signaling pathways linked to platelet function that are altered by PI. Because some of these biochemical alterations are similar to those seen arising in the context of routine platelet storage lesion development occurring during blood bank storage, we lack a complete picture of the contribution of PI treatment to impaired platelet functionality. A model generated using data from currently available publications places the signaling protein kinase p38 as a central player regulating a variety of mechanisms triggered in platelets by PI systems.

A comprehensive proteomics study on platelet concentrates: Platelet proteome, storage time and Mirasol pathogen reduction technology

Platelet concentrates (PCs) represent a blood transfusion product with a major concern for safety as their storage temperature (20-24°C) allows bacterial growth, and their maximum storage time period (less than a week) precludes complete microbiological testing. Pathogen inactivation technologies (PITs) provide an additional layer of safety to the blood transfusion products from known and unknown pathogens such as bacteria, viruses, and parasites. In this context, PITs, such as Mirasol Pathogen Reduction Technology (PRT), have been developed and are implemented in many countries. However, several studies have shown in vitro that Mirasol PRT induces a certain level of platelet shape change, hyperactivation, basal degranulation, and increased oxidative damage during storage. It has been suggested that Mirasol PRT might accelerate what has been described as the platelet storage lesion (PSL), but supportive molecular signatures have not been obtained. We aimed at dissecting the influence of both variables, that is, Mirasol PRT and storage time, at the proteome level. We present comprehensive proteomics data analysis of Control PCs and PCs treated with Mirasol PRT at storage days 1, 2, 6, and 8. Our workflow was set to perform proteomics analysis using a gel-free and label-free quantification (LFQ) approach. Semi-quantification was based on LFQ signal intensities of identified proteins using MaxQuant/Perseus software platform. Data are available via ProteomeXchange with identifier PXD008119. We identified marginal differences between Mirasol PRT and Control PCs during storage. However, those significant changes at the proteome level were specifically related to the functional aspects previously described to affect platelets upon Mirasol PRT. In addition, the effect of Mirasol PRT on the platelet proteome appeared not to be exclusively due to an accelerated or enhanced PSL. In summary, semi-quantitative proteomics allows to discern between proteome changes due to Mirasol PRT or PSL, and proves to be a methodology suitable to phenotype platelets in an unbiased manner, in various physiological contexts.

Pathogen reduction technologies: The pros and cons for platelet transfusion

The transfusion of platelets is essential for diverse pathological conditions associated with thrombocytopenia or platelet disorders. To maintain optimal platelet quality and functions, platelets are stored as platelet concentrates (PCs) at room temperature under continuous agitation-conditions that are permissive for microbial proliferation. In order to reduce these contaminants, pathogen reduction technologies (PRTs) were developed by the pharmaceutical industry and subsequently implemented by blood banks. PRTs rely on chemically induced cross-linking and inactivation of nucleic acids. These technologies were initially introduced for the treatment of plasma and, more recently, for PCs given the absence of a nucleus in platelets. Several studies verified the effectiveness of PRTs to inactivate a broad array of bacteria, viruses, and parasites. However, the safety of PRT-treated platelets has been questioned in other studies, which focused on the impact of PRTs on platelet quality and functions. In this article, we review the literature regarding PRTs, and present the advantages and disadvantages related to their application in platelet transfusion medicine.

Redox Proteomics and Platelet Activation: Understanding the Redox Proteome to Improve Platelet Quality for Transfusion

Blood banks use pathogen inactivation (PI) technologies to increase the safety of platelet concentrates (PCs). The characteristics of PI-treated PCs slightly differ from those of untreated PCs, but the underlying reasons are not well understood. One possible cause is the generation of oxidative stress during the PI process. This is of great interest since reactive oxygen species (ROS) act as second messengers in platelet functions. Furthermore, there are links between protein oxidation and phosphorylation, another mechanism that is critical for cell regulation. Current research efforts focus on understanding the underlying mechanisms and identifying new target proteins. Proteomics technologies represent powerful tools for investigating signaling pathways involving ROS and post-translational modifications such as phosphorylation, while quantitative techniques enable the comparison of the platelet resting state versus the stimulated state. In particular, redox cysteine is a key player in platelet activation upon stimulation by different agonists. This review highlights the experiments that have provided insights into the roles of ROS in platelet function and the implications for platelet transfusion, and potentially in diseases such as inflammation and platelet hyperactivity. The review also describes the implication of redox mechanism in platelet storage considerations.

Peculiarities of studying the effects of pathogen reduction technologies on platelets

The transfusion of platelet concentrates (PCs) is mainly used for treatment of thrombocytopenic, trauma or surgery patients. The integrity and safety of these platelet preparations, however, is compromised by the presence of pathogens, such as viruses, bacteria and parasites. The transfer of allogeneic donor leukocytes contaminating PCs can also potentially cause adverse reactions in recipients. These considerations prompted the development and implementation of pathogen reduction technologies (PRT), which are based on chemically induced cross-linking and inactivation of nucleic acids. While the incumbent PRT may provide some protection against transfusion-transmitted infections, they are ineffective against infectious prions and may not inactivate other emerging pathogens. In addition, the safety of PRT concerning platelet viability and function has been questioned in several reports. Recent studies suggest that PRT, such as Intercept, may adversely affect the messenger RNA (mRNA) and microRNA content of platelets, as well as their functional integrity, which may compromise the clinical benefits of PRT. Here, we will discuss about the peculiarities of studying the effects of PRT on platelets, which will need to be taken into account in future studies aimed to characterize further, and polish, the rugged side of this otherwise useful and potentially important approach in transfusion medicine.

Inactivation of dengue, chikungunya, and Ross River viruses in platelet concentrates after treatment with ultraviolet C light

BACKGROUND

Arboviruses, including dengue (DENV 1-4), chikungunya (CHIKV), and Ross River (RRV), are emerging viruses that are a risk for transfusion safety globally. An approach for managing this risk is pathogen inactivation, such as the THERAFLEX UV-Platelets system. We investigated the ability of this system to inactivate the above mentioned arboviruses.

STUDY DESIGN AND METHODS

DENV 1-4, CHIKV, or RRV were spiked into buffy coat (BC)-derived platelet (PLT) concentrates in additive solution and treated with the THERAFLEX UV-Platelets system at the following doses: 0.05, 0.1, 0.15, and 0.2 J/cm(2) (standard dose). Pre- and posttreatment samples were taken for each dose, and the level of viral infectivity was determined.

RESULTS

At the standard ultraviolet C (UVC) dose (0.2 J/cm(2) ), viral inactivation of at least 4.43, 6.34, and 5.13 log or more, was observed for DENV 1-4, CHIKV, and RRV, respectively. A dose dependency in viral inactivation was observed with increasing UVC doses.

CONCLUSIONS

Our study has shown that DENV, CHIKV, and RRV, spiked into BC-derived PLT concentrates, were inactivated by the THERAFLEX UV-Platelets system to the limit of detection of our assay, suggesting that this system could contribute to the safety of PLT concentrates with respect to these emerging arboviruses.

Improving platelet transfusion safety: biomedical and technical considerations

Platelet concentrates account for near 10% of all labile blood components but are responsible for more than 25% of the reported adverse events. Besides factors related to patients themselves, who may be particularly at risk of side effects because of their underlying illness, there are aspects of platelet collection and storage that predispose to adverse events. Platelets for transfusion are strongly activated by collection through disposal equipment, which can stress the cells, and by preservation at 22 °C with rotation or rocking, which likewise leads to platelet activation, perhaps more so than storage at 4 °C. Lastly, platelets constitutively possess a very large number of bioactive components that may elicit pro-inflammatory reactions when infused into a patient. This review aims to describe approaches that may be crucial to minimising side effects while optimising safety and quality. We suggest that platelet transfusion is complex, in part because of the complexity of the "material" itself: platelets are highly versatile cells and the transfusion process adds a myriad of variables that present many challenges for preserving basal platelet function and preventing dysfunctional activation of the platelets. The review also presents information showing--after years of exhaustive haemovigilance--that whole blood buffy coat pooled platelet components are extremely safe compared to the gold standard (i.e. apheresis platelet components), both in terms of acquired infections and of immunological/inflammatory hazards.

In vitro comparison of cryopreserved and liquid platelets: potential clinical implications

BACKGROUND

Platelet (PLT) concentrates can be cryopreserved in dimethyl sulfoxide (DMSO) and stored at -80°C for 2 years. These storage conditions improve availability in both rural and military environments. Previous phenotypic and in vitro studies of cryopreserved PLTs are limited by comparison to fresh liquid-stored PLTs, rather than PLTs stored over their clinically relevant shelf life. Further, nothing is known of the effect of reconstituting cryopreserved PLTs in plasma stored at a variety of clinically relevant temperatures.

STUDY DESIGN AND METHODS

Apheresis PLTs were either stored at room temperature for 5 days or cryopreserved at -80°C with 5% DMSO. Cryopreserved PLTs were thawed at 37°C and reconstituted in plasma (stored at different temperatures) and compared to fresh and expired liquid-stored PLTs. In vitro assays were performed to assess glycoprotein expression, PLT activity, microparticle content, and function.

RESULTS

Compared to liquid PLTs over storage, cryopreserved PLTs had reduced expression of the key glycoprotein receptors GPIbα and GPIIb. However, the proportion of PLTs expressing activation markers CD62P and CD63 was similar between cryopreserved and liquid-stored PLTs at expiry. Cryopreserved PLT components contained significantly higher numbers of phosphatidylserine- and tissue factor-positive microparticles than liquid-stored PLTs, and these microparticles reduced the time to clot formation and increased thrombin generation.

CONCLUSION

There are distinct differences between cryopreserved and liquid-stored PLTs. Cryopreserved PLTs also have an enhanced hemostatic activity. Knowledge of these in vitro differences will be essential to understanding the outcomes of a clinical trial comparing cryopreserved PLTs and liquid PLTs stored for various durations.

Proteomics of apheresis platelet supernatants during routine storage: Gender-related differences

Proteomics has identified potential pathways involved in platelet storage lesions, which correlate with untoward effects in the recipient, including febrile non-haemolytic reactions. We hypothesize that an additional pathway involves protein mediators that accumulate in the platelet supernatants during routine storage in a donor gender-specific fashion. Apheresis platelet concentrates were collected from 5 healthy males and 5 females and routinely stored. The 14 most abundant plasma proteins were removed and the supernatant proteins from days 1 and 5 were analyzed via 1D-SDS-PAGE/nanoLC-MS/MS, before label-free quantitative proteomics analyses. Findings from a subset of 18 proteins were validated via LC-SRM analyses against stable isotope labeled standards. A total of 503 distinct proteins were detected in the platelet supernatants from the 4 sample groups: female or male donor platelets, either at storage day 1 or 5. Proteomics suggested a storage and gender-dependent impairment of blood coagulation mediators, pro-inflammatory complement components and cytokines, energy and redox metabolic enzymes. The supernatants from female donors demonstrated increased deregulation of structural proteins, extracellular matrix proteins and focal adhesion proteins, possibly indicating storage-dependent platelet activation. Routine storage of platelet concentrates induces changes in the supernatant proteome, which may have effects on the transfused patient, some of which are related to donor gender.

BIOLOGICAL SIGNIFICANCE

The rationale behind this study is that protein components in platelet releasates have been increasingly observed to play a key role in adverse events and impaired homeostasis in transfused recipients. In this view, proteomics has recently emerged as a functional tool to address the issue of protein composition of platelet releasates from buffy coat-derived platelet concentrates in the blood bank. Despite early encouraging studies on buffy coat-derived platelet concentrates, platelet releasates from apheresis platelets have not been hitherto addressed by means of extensive proteomics technologies. Indeed, apheresis platelets are resuspended in donors' plasma, which hampers detection of less abundant proteins, owing to the overwhelming abundance of albumin (and a handful of other proteins), and the dynamic range of protein concentrations of plasma proteins. In order to cope with these issues, we hereby performed an immuno-affinity column-based depletion of the 14 most abundant plasma proteins. Samples were thus assayed via GeLC-MS, a workflow that allowed us to cover an unprecedented portion of the platelet supernatant proteome, in comparison to previous transfusion medicine-oriented studies in the literature. Finally, we hereby address the issue of biological variability, by considering the donor gender as a key factor influencing the composition of apheresis platelet supernatants. As a result, we could conclude that platelet supernatants from male and female donors are not only different in the first place, but they also store differently. This conclusion has been so far only suggested by classic transfusion medicine studies, but has been hitherto unsupported by actual biochemistry/proteomics investigations. In our opinion, the main strengths of this study are related to the analytical workflow (immunodepletion and GeLC-MS) and proteome coverage, the translational validity of the results (from a transfusion medicine standpoint) and the biological conclusion about the intrinsic (and storage-dependent) gender-related differences of platelet supernatants.

Transfusion efficacy of apheresis platelet concentrates irradiated at the day of transfusion is significantly superior compared to platelets irradiated in advance

BACKGROUND

Gamma irradiation is currently the standard care to avoid transfusion-associated graft-versus-host disease. Guidelines on gamma irradiation of blood components state that platelets (PLTs) can be irradiated at any stage in their 5-day storage and can thereafter be stored up to their normal shelf life of 5 days after collection. In this study, we explored whether the timing of irradiation has an effect on transfusion efficacy of apheresis PLT concentrates (APCs).

METHODS

Based on the 1-hour percent PLT recovery (PPR1h), transfusion efficacy of 1,000 eligible APCs transfused to 144 children were evaluated retrospectively. PPR1h was compared in transfused APCs irradiated at the day of transfusion and APCs irradiated in advance.

RESULTS

In univariate analysis, transfusion efficacy of APCs irradiated in advance was significantly lower than that of APCs irradiated at the day of transfusion (mean PPR1h 27.7 vs. 35.0%; p = 0.007). This was confirmed in multivariate analysis (p = 0.030). Compared to non-irradiated APCs, transfusion efficacy of APCs irradiated at the day of transfusion was not significantly inferior (mean difference -2.8%; 95% CI -6.1 to 0.5%; p = 0.092), but APCs irradiated in advance were clearly less efficient (mean difference -8.1%; 95% CI -12.2 to -4.0%; p < 0.001).

CONCLUSION

Our data strongly support that APCs should not be irradiated in advance, 1.e., ≥24 h before transfusion.

LC-MS/MS analysis and comparison of oxidative damages on peptides induced by pathogen reduction technologies for platelets

Pathogen reduction technologies (PRT) are photochemical processes that use a combination of photosensitizers and UV-light to inactivate pathogens in platelet concentrates (PCs), a blood-derived product used to prevent hemorrhage. However, different studies have questioned the impact of PRT on platelet function and transfusion efficacy, and several proteomic analyses revealed possible oxidative damages to proteins. The present work focused on the oxidative damages produced by the two main PRT on peptides. Model peptides containing residues prone to oxidation (tyrosine, histidine, tryptophane, and cysteine) were irradiated with a combination of amotosalen/UVA (Intercept process) or riboflavin/UVB (Mirasol-like process). Modifications were identified and quantified by liquid chromatography coupled to tandem mass spectrometry. Cysteine-containing peptides formed disulfide bridges (R-SS-R, -2 Da; favored following amotosalen/UVA), sulfenic and sulfonic acids (R-SOH, +16 Da, R-SO3H, +48 Da, favored following riboflavin/UVB) upon treatment and the other amino acids exhibited different oxidations revealed by mass shifts from +4 to +34 Da involving different mechanisms; no photoadducts were detected. These amino acids were not equally affected by the PRT and the combination riboflavin/UVB generated more oxidation than amotosalen/UVA. This work identifies the different types and sites of peptide oxidations under the photochemical treatments and demonstrates that the two PRT may behave differently. The potential impact on proteins and platelet functions may thus be PRT-dependent.