Dose-dependent inactivation of Plasmodium falciparum in red blood cell concentrates by treatment with short-wavelength ultraviolet light.

BACKGROUND AND OBJECTIVES: Plasmodium species are naturally transmitted by Anopheles mosquitos. The parasite infects red blood cells (RBCs) and can be transfused with blood products. In non-endemic areas, the main risk of infection arises from travellers coming back and people immigrating from malaria-endemic regions. Endemic countries face a permanent risk of infection from transfusion-transmitted malaria (TTM). TTM may cause life-threatening complications in patients dependent on blood donations. This study aimed to investigate the efficacy of Plasmodium falciparum inactivation in RBC units by treatment with short-wavelength ultraviolet C (UVC) light in the absence of photochemical additives. MATERIALS AND METHODS: RBC units were spiked with P. falciparum to a parasite density of 0.1%-1% and irradiated with up to 4.5 J/cm2 UVC. The parasite density of UVC-treated dilution series and untreated controls were compared over 3 weeks after irradiation. RESULTS: The lowest dose of 1.5 J/cm2 UVC led to a 3.1 log reduction in parasite load compared with the untreated control. The inactivation capacity was dose-dependent. Strikingly, 4.5 J/cm2 led to ≥5.3 log unit reduction, which was equivalent to a complete inactivation in two out of three experiments. CONCLUSION: Pathogen reduction with UVC light was previously shown to be effective for different bacteria and viruses, but the inactivation of parasites in RBC concentrates was not addressed until now. The present study provides evidence for significant inactivation of P. falciparum-infected RBCs by UVC light.

Increase of Phosphoprotein Expressions in Amotosalen/UVA-Treated Platelet Concentrates.

Background: Pathogen inactivation treatment (PIT) has been shown to alter platelet function, phenotype, morphology and to induce a faster aging of platelet concentrates (PCs). Key pieces of information are still missing to understand the impacts of PITs at the cellular level. Objectives: This study investigated the impact of amotosalen/UVA on PCs, from a post-translational modifications (PTM) point of view. Phosphoproteomic analyses were conducted on resting platelets, right after the amotosalen/UVA treatment and compared with untreated PCs. Method: A two-arm study setting was carried out to compare PIT (amotosalen/UVA) to untreated PCs, on day 1 post-donation. Based on a pool-and-split approach, 12 PCs were split into two groups (treated and untreated). Quantitative phosphoproteomics was performed using TMT technology to study the changes of phosphoproteins right after the PIT. Results: A total of 3,906 proteins and 7,334 phosphosites were identified, and 2,473 proteins and 2,214 phosphosites were observed in at least 5 to 6 replicates. Compared to untreated platelets, PIT platelets exhibited an upregulation of the phosphorylation effects, with 109 phosphosites identified with a higher than 2-fold change. Two pathways were clearly identified. The mitogen activated protein kinases (MAPKs) cascade, which triggers the granule secretion and the activation of the pS15 HSPB1. One of the shape change pathways was also observed with the inhibition of the Threonine 18 and Serine 19 phosphorylations on myosin light chain (MLC) protein after the amotosalen/UVA treatment. Conclusions: This work provides a deep insight into the impact of amotosalen/UVA treatment from a phosphoprotein viewpoint on resting platelets. Clear changes in phosphorylation of proteins belonging to different platelet pathways were quantified. This discovery corroborates previous findings and fills missing parts of the effect of photochemical treatments on platelets.

Inactivation of SARS-CoV-2 infectivity in platelet concentrates or plasma following treatment with ultraviolet C light or with methylene blue combined with visible light.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unlikely to be a major transfusion-transmitted pathogen; however, convalescent plasma is a treatment option used in some regions. The risk of transfusion-transmitted infections can be minimized by implementing Pathogen Inactivation (PI), such as THERAFLEX MB-plasma and THERAFLEX UV-Platelets systems. Here we examined the capability of these PI systems to inactivate SARS-CoV-2. STUDY DESIGN AND METHODS: SARS-CoV-2 spiked plasma units were treated using the THERAFLEX MB-Plasma system in the presence of methylene blue (~0.8 µmol/L; visible light doses: 20, 40, 60, and 120 [standard] J/cm2 ). SARS-CoV-2 spiked platelet concentrates (PCs) were treated using the THERAFLEX UV-platelets system (UVC doses: 0.05, 0.10, 0.15, and 0.20 [standard] J/cm2 ). Samples were taken prior to the first and after each illumination dose, and viral infectivity was assessed using an immunoplaque assay. RESULTS: Treatment of spiked plasma with the THERAFLEX MB-Plasma system resulted in an average ≥5.03 log10 reduction in SARS-CoV-2 infectivity at one third (40 J/cm2 ) of the standard visible light dose. For the platelet concentrates (PCs), treatment with the THERAFLEX UV-Platelets system resulted in an average ≥5.18 log10 reduction in SARS-CoV-2 infectivity at the standard UVC dose (0.2 J/cm2 ). CONCLUSIONS: SARS-CoV-2 infectivity was reduced in plasma and platelets following treatment with the THERAFLEX MB-Plasma and THERAFLEX UV-Platelets systems, to the limit of detection, respectively. These PI technologies could therefore be an effective option to reduce the risk of transfusion-transmitted emerging pathogens.

Pathogen reduction with methylene blue does not have an impact on the clinical effectiveness of COVID-19 convalescent plasma.

BACKGROUND AND OBJECTIVES: There is a concern about a possible deleterious effect of pathogen reduction (PR) with methylene blue (MB) on the function of immunoglobulins of COVID-19 convalescent plasma (CCP). We have evaluated whether MB-treated CCP is associated with a poorer clinical response compared to other inactivation systems at the ConPlas-19 clinical trial. MATERIALS AND METHODS: This was an ad hoc sub-study of the ConPlas-19 clinical trial comparing the proportion of patients transfused with MB-treated CCP who had a worsening of respiration versus those treated with amotosalen (AM) or riboflavin (RB). RESULTS: One-hundred and seventy-five inpatients with SARS-CoV-2 pneumonia were transfused with a single CCP unit. The inactivation system of the CCP units transfused was MB in 90 patients (51.4%), RB in 60 (34.3%) and AM in 25 (14.3%). Five out of 90 patients (5.6%) transfused with MB-treated CCP had worsening respiration compared to 9 out of 85 patients (10.6%) treated with alternative PR methods (p = 0.220). Of note, MB showed a trend towards a lower rate of respiratory progressions at 28 days (risk ratio, 0.52; 95% confidence interval, 0.18-1.50). CONCLUSION: Our data suggest that MB-treated CCP does not provide a worse clinical outcome compared to the other PR methods for the treatment of COVID-19.

Chemical Pretreatments and Anaerobic Digestion Shape the Virome and Functional Microbiome in Fecal Sludge.

The decomposition and pathogen inactivation of fecal sludge (FS) are vitally important for safely managing onsite sanitation and protecting public and environmental health. However, the microbiome and virome assemblages in FS after chemical and biological treatments remain unclear. Here, we reported the differences in the solid reduction and microbiomes of FS subjected to potassium ferrate (PF), alkali (ALK), and sodium hypochlorite (NaClO) pretreatments and anaerobic digestion (AD). The PF and NaClO pretreatments enhanced FS hydrolysis and pathogen suppression, respectively; AD suppressed Gram-positive bacteria. Most of the viromes were those of bacteriophages, which were also shaped by chemical pretreatments and AD. Metatranscriptome analysis revealed distinct gene expression patterns between the PF- and ALK-pretreated FS and the subsequent AD. Differentially expressed gene profiles indicated that genes related to biological processes, molecular functions, and transcriptional regulators were upregulated in ALK-AD and PF-AD samples. These findings suggested that the effect of different treatment technologies on the viral diversity, pathogen abundance, and metabolic function of the core microbiome extends beyond FS decomposition and that the use of combined processes would provide possible alternatives for FS management in pandemic emergencies.

Transfusion-Transmitted Hepatitis A Virus, France, 2018.

We report a transfusion-transmitted hepatitis A virus infection in an immunocompromised patient in France, detected shortly after a transfusion of pathogen-reduced pooled platelets. This case raises questions about the efficacy of donor screening methods. Additional safety measures, such as routine donation screening, should be considered.

Hepatitis E virus is effectively inactivated by methylene blue plus light treatment.

BACKGROUND AND OBJECTIVES: Photodynamic treatment with methylene blue (MB) and visible light is a well-established pathogen inactivation system for human plasma. This technique is routinely used in different countries. MB/light treatment was shown to inactivate several transfusion-transmittable viruses, but its efficiency for the inactivation of the quasi-enveloped hepatitis E virus (HEV) has not yet been investigated. MATERIALS AND METHODS: Plasma units were spiked with cell culture-derived HEV and treated with the THERAFLEX MB-Plasma system using various light doses (30, 60, 90, and 120 J/cm2 ). HEV titers in pre- and post-treatment samples were determined by virus titration and a large-volume plating assay to improve the detection limit of the virus assay. RESULTS: THERAFLEX MB-Plasma efficiently inactivated HEV in human plasma. Even the lowest light dose of 30 J/cm2 inactivated HEV down to the limit of detection, with a mean log reduction factor of greater than 2.4 for the total process. CONCLUSION: Our study demonstrates that the THERAFLEX MB-Plasma system effectively inactivates HEV in human plasma.

New ultraviolet C light-based method for pathogen inactivation of red blood cell units.

BACKGROUND: Pathogen inactivation (PI) technologies for platelet concentrates and plasma are steadily becoming more established, but new PI treatment options for red blood cells (RBCs), the most commonly used blood component, still need to be developed. We present a novel approach to inactivating pathogens in RBC units employing ultraviolet C (UVC) light. METHODS: Whole blood-derived leukoreduced RBCs suspended in PAGGS-C, a third generation additive solution, served as test samples, and RBCs in PAGGS-C or SAG-M as controls. Vigorous agitation and hematocrit reduction by diluting the RBCs with additional additive solution during illumination ensured that UVC light penetrated and inactivated the nine bacteria and eight virus species tested. Bacterial and viral infectivity assays and in vitro analyses were performed to evaluate the system's PI capacity and to measure the RBC quality, metabolic, functional, and blood group serological parameters of UVC-treated versus untreated RBCs during 36-day storage. RESULTS: UVC treatment of RBCs in the PAGGS-C additive solution did not alter RBC antigen expression, but significantly influenced some in vitro parameters. Compared to controls, hemolysis was higher in UVC-treated RBC units, but was still below 0.8% at 36 days of storage. Extracellular potassium increased early after PI treatment and reached ≤70 mmol/L by the end of storage. UVC-treated RBC units had higher glucose and 2,3-diphosphoglycerate levels than controls. CONCLUSION: As UVC irradiation efficiently reduces the infectivity of relevant bacteria and viruses while maintaining the quality of RBCs, the proposed method offers a new approach for PI of RBC concentrates.

Residual risks of bacterial contamination for pathogen-reduced platelet components.

Platelet components are commonly transfused to patients for a variety of indications, including patients with low platelet counts or patients with platelet dysfunction who are bleeding or at high risk of bleeding. Although the risk of pathogen contamination of platelet components has declined significantly over the last 40 years, it remains a concern for the patients, for blood banks and for physicians. Pathogen inactivation (PI) technologies have been developed to mitigate this risk. This review focuses on the residual risks of transfusion-transmitted bacterial infections by platelet transfusion after PI. We describe and assess the relationship between the bacterial load and the timing and capacity of reduction of the different PI technologies, as well as the risks that could represent spore-forming microorganisms and the possible introduction of microorganisms after PI.

HIV residual risk in Canada for apheresis source plasma donation without deferral for men who have sex with men.

BACKGROUND AND OBJECTIVES: In Canada, men having sex with men (MSM) are deferred for 3 months from last sexual contact to reduce human immunodeficiency virus (HIV) risk to recipients. The aim of this paper was to model the Canadian residual risk of HIV-positive source plasma incorporating pathogen inactivation (PI) under no MSM deferral scenarios for apheresis plasma donations. MATERIALS AND METHODS: A combined Bayesian network (BN) and Monte Carlo approach were implemented to estimate the HIV residual risk under 3-month deferral compared with no deferral without quarantine scenarios for MSM donors. Models involve the stochastic generation of donation and its infection status based on its corresponding simulated donor profile. Viral load reduction conferred by PI used by source plasma fractionators was simulated. Model parameters were derived from Héma-Québec and Canadian Blood Services data, viral loads in a large sample of HIV-positive US blood donors, CSL Behring documentation and from published data. RESULTS: In the most likely scenario for the 3-month deferral model, there were 2.71 positive donations per 1,000,000 donations (95% confidence interval [CI] 2.63-2.78). For the no-deferral model, there were 3.01 positive donations per 1,000,000 donations (95% CI 2.94-3.09). For both scenarios, the risk of having an infectious pool was 0 in 300,000 pools (95% CI 0-0.0000123) after consideration of PI. CONCLUSION: Based on simulation results, there would be a negligible HIV residual risk associated with the removal of a time-based MSM deferral without quarantine for source plasma incorporating PI.

Impact of the pathogen inactivation process on the migration of di(2-ethylhexyl) phthalate from plasma bags.

BACKGROUND AND OBJECTIVES: Di(2-ethylhexyl) phthalate (DEHP) is a toxic plasticizer that is commonly used in the manufacture of polyvinyl chloride (PVC) blood bags. It is well known that DEHP can migrate from a medical device into the blood plasma. For safety reasons, pathogens in plasma must be inactivated; however, this process may increase DEHP migration. Here, we assessed the impact of illumination-based pathogen inactivation on the migration of DEHP from PVC bags into plasma. MATERIALS AND METHODS: Pairs of native PVC-DEHP plasma bags were pooled. Each pool was then split into a pathogen-inactivated bag and a control bag. After illumination, the plasma concentrations of DEHP and its main metabolite (mono(2-ethylhexyl) phthalate, MEHP) in each bag were assayed and compared using liquid chromatography-tandem mass spectrometry. Concentrations were evaluated in repeated-measures, two-way analyses of variance. RESULTS: The MEHP concentration was significantly associated with storage but not with illumination (p = 0.0001). The DEHP concentration stayed constant throughout the storage period. The DEHP equivalent concentration (corresponding to the overall plasticizer migration rate into plasma) was not significantly associated with illumination (p = 0.3) or storage (p = 0.09; mean ± standard deviation of the mean DEHP concentration for all conditions: 147.9 ± 11.3 µg/ml). CONCLUSION: Illumination-based inactivation of pathogens in plasma did not increase the DEHP equivalent concentration, relative to control (non-inactivated) plasma.

Synergistic Nanowire-Enhanced Electroporation and Electrochlorination for Highly Efficient Water Disinfection.

Conventional water disinfection methods such as chlorination typically involve the generation of harmful disinfection byproducts and intensive chemical consumption. Emerging electroporation disinfection techniques using nanowire-enhanced local electric fields inactivate microbes by damaging their outer structures without byproduct formation or chemical dosing. However, this physical-based method suffers from a limited inactivation efficiency under high water flux due to an insufficient contact time. Herein, we integrate electrochlorination with nanowire-enhanced electroporation to achieve a synergistic flow-through process for efficient water disinfection targeting bacteria and viruses. Electroporation at the cathode induces sub-lethal damages on the microbial outer structures. Subsequently, electrogenerated active chlorine at the anode aggravates these electroporation-induced injuries to the level of lethal damage. This sequential flow-through disinfection system achieves complete disinfection (>6.0-log) under a very high water flux of 2.4 × 104 L/(m2 h) with an applied voltage of 2.0 V. This disinfection efficiency is 8 times faster than that of electroporation alone. Further, the specific energy consumption for the disinfection by this novel process is extremely low (8 × 10-4 kW h/m3). Our results demonstrate a promising method for rapid and energy-efficient water disinfection by coupling electroporation with electrochlorination to meet vital needs for pathogen elimination.

Pathogen inactivation of platelets for transfusion.

Bacterial contamination of blood components is a recurrent topic in transfusion medicine community. This issue is even more important with platelet transfusions because of storage of platelet components at room temperature for 5 days. Pathogen inactivation methods are a proactive approach to deal with an infectious agent. All available methods use UV light, with or without a photosensitizer, to inactivate potential pathogens. As with other medical interventions, pathogen inactivation methods carry benefits and risks. Among benefits, inactivation of known and unknown transfusion-transmitted pathogens, inactivation of residual leukocytes, and increased storage length from 5 to 7 days are the most interesting. The main risk is the impact on clinical efficacy of pathogen-reduced platelets. After inactivation, pathogen-reduced platelets are associated with a lower number of platelets in the final product, lower 24-hour corrected count increment, and shorter transfusion interval when compared with non-inactivated platelets. However, eight of nine randomized controlled trials showed that transfusing pathogen-reduced platelets were not inferior to transfusing usual platelet components in the prevention of bleeding episodes. In conclusion, in our opinion, increasing safety of platelet transfusions with pathogen inactivation methods is worthy, even the trade-off of causing damage to platelets.

Pathogen inactivation treatment of triple-dose apheresis platelets with amotosalen and ultraviolet a light.

BACKGROUND: A triple storage (TS) set allows for pathogen inactivation (PI) treatment of triple-dose apheresis platelet products with amotosalen + UVA. We evaluated the quality and metabolic parameters of platelet concentrates (PCs) pathogen inactivated and stored for 7 days. MATERIALS AND METHODS: Twelve triple-dose products collected with two different apheresis platforms were treated with amotosalen+UVA. Products were split into three single-dose units. Testing was made pretreatment, after splitting, at days 5 and 7 of storage. RESULTS: Single-dose PI PCs had a mean platelet content of 2.89 ± 0.35 x 1011 . From baseline to day 7, pH remained stable (7.1 ± 0.1 vs. 7.0 ± 0.1), pO2 increased (11.3 ± 2.4 vs. 18.3 ± 3.5 kPa) as did LDH (201 ± 119 vs. 324 ± 203 U/L) and lactate (3.6 ± 1.7 vs. 12.1 ± 1.5 mmol/L) (all p < 0.01); pCO2 decreased (4.1 ± 0.8 vs. 1.5 ± 0.7 mmHg; p < 0.01) and so did bicarbonate (6.6 ± 1.1 vs. 2.5 ± 1.4 mmol/L), glucose (5.6 ± 1.2 vs. 0.4 ± 0.4 mmol/L) and ATP (3.4 ± 0.9 vs. 2.5 ± 1.4 nmol/108 platelets) (all p < 0.05). CONCLUSION: Triple-dose PCs processed with the TS sets fulfilled the quality requirements and displayed metabolic changes of expected extent during 7-day storage.

Fate of Clostridia and other spore-forming Firmicute bacteria during feedstock anaerobic digestion and aerobic composting.

Pathogenic spore-forming Firmicutes are commonly present in animal and human wastes that are used as fertilizers in crop production. Pre-treatments of organic waste prior to land application offer the potential to abate enteric microorganisms, and therefore reduce the risk of contamination of crops or adjacent water resources with pathogens carried in these materials. The inactivation and reduction of gram-positive spore formers such as Clostridium spp., Clostridioides spp. and Bacillus spp. from animal and human waste can be challenging given the recalcitrance of the spores these bacteria produce. Given the significance of these organisms to human and animal health, information concerning spore-forming bacteria inactivation during anaerobic digestion (AD) and aerobic composting (AC) is required as the basis for recommending safe organic waste management practices. In this review, an assessment of the inactivation of spore-forming Firmicutes during AD and AC was conducted to provide guidance for practical management of organic matrices of animal or human origin. Temperature and pH may be the main factors contributing to the inactivation of spore-forming Firmicutes during batch lab-scale AD (log reduction <0.5-5 log). In continuous digesters, wet AD systems do not effectively inactivate spore-forming Firmicutes even under thermopholic conditions (log reduction -1.09 - 0.98), but dry AD systems could be a feasible management practice to inactivate spore-forming Firmicutes from organic materials with high solid content (log reduction 1.77-3.1). In contrast, composting is an effective treatment to abate spore-forming Firmicutes (log reduction 1.7-6.5) when thermophilic conditions last at least six consecutive days. Temperature, moisture content and composting scale are the key operating conditions influencing the inactivation of spore-forming Firmicutes during composting. Where possible, undertaking AD with subsequent composting to ensure the biosafety of digestate before its downstream processing and recycling is recommended to abate recalcitrant bacteria in digestate.

Evaluation of the hemostatic capacity of methylene blue-treated liquid (not frozen) plasma stored up 14 days at 2° to 6°C.

BACKGROUND: Early plasma transfusion for management of bleeding, particularly trauma, is associated with better outcomes. Improving the availability/safety of plasma transfusion for patients is essential for transfusion services. The aim of this study is to evaluate the hemostatic capacity of methylene-blue (MB) liquid (not frozen) plasma over time. MATERIALS AND METHODS: Twenty whole blood-derived plasma units collected from male donors were separated and processed within 18 h of collection. Individual plasmas were treated with MB and stored in liquid status at 2-6°C for 14 days. A range of coagulation assays, including thrombin generation, rotational thromboelastometry (ROTEM), and Thrombodynamics were tested at different time-points, together with bacterial growth. RESULTS: Apart from Factor (F)XII, other coagulation factors (fibrinogen, FV, FVIII, FXI) reduced significantly after MB treatment, with levels remaining stable except for FVIII afterward. By day 14, most clotting factors were >0.7 IU/ml, apart from FVIII. There was a disproportionate decrease in Protein S (PS) activity compared to free PS antigen and by day 14 its value was ~50%. There was no significant difference in maximum clot formation (ROTEM) and clot-density (Thrombodynamics) over time. Endogenous thrombin potential (Thrombin-Generation), clot-size, and velocity index (Thrombodynamics) decreased significantly over time consistent with clotting factor reduction. There was no bacterial growth. CONCLUSIONS: MB-treated liquid plasma stored at 2-6°C can be used for up to 14 days: the long shelf-life, the liquid status, and the MB treatment will improve its availability for management of bleeding as well as providing a safe component from pathogens.

Evaluation of riboflavin and ultraviolet light treatment against Klebsiella pneumoniae in whole blood-derived platelets: A pilot study.

BACKGROUND: Bacterial contamination of platelet concentrates (PCs) is the predominant cause of infectious transfusion reactions. The Pathogen Inactivation Mirasol system was implemented at the King Faisal Specialist Hospital (Saudi Arabia) to reduce the risk of transfusing contaminated PCs. This pilot study evaluated the effectiveness of Mirasol against Klebsiella pneumoniae, a pathogen associated with transfusion reactions, in whole blood-derived PCs. STUDY DESIGN AND METHODS: Whole blood (WB) units inoculated with one of six K. pneumoniae strains (five clinical isolates and ATCC-700603) at a concentration of 3-38 CFU/unit, were processed using the platelet-rich plasma (PRP) method. Each spiked PC was pooled with four unspiked units. The pooled PC was split into three Mirasol storage bags: an untreated unit (control), and two units treated with Mirasol at 26 and 32 h post-WB collection, respectively. PC samples obtained before and after Mirasol treatment were used for BacT/ALERT cultures and determination of bacteria quantification. Each experiment was repeated three independent times. RESULTS: Five strains were detected prior to PC treatment (24 h post-WB spiking), while one clinical isolate was not detected. Mirasol treatment after 26 h of WB collection resulted in complete inactivation of all K. pneumoniae strains. However, treatment 32 h post-WB collection resulted in the breakthrough of one clinical isolate in two of the three replicates with ~7.8 log10 CFU/unit detected on day 5 of PC storage. CONCLUSION: Delayed Mirasol treatment from 26 to 32 h post-WB collection, resulted in one breakthrough. These results highlight the importance of minimizing the time between WB collection and PI treatment.

Releasates of riboflavin/UV-treated platelets: Microvesicles suppress cytokine-mediated endothelial cell migration/proliferation.

BACKGROUND: Accelerated development of the platelet (PLT) storage lesion upon pathogen inactivation (PI) is associated with the release of proteins from granules and platelet microvesicles (PMVs). Whether PI treatments alter the interaction between PLT factors and the vessel endothelium is of interest in understanding the risk profile of these technologies. STUDY DESIGN AND METHODS: In a pool-and-split study, one platelet concentrate (PC) was treated with riboflavin/UV (RF/UV) light, while the other one was kept as an untreated control. Releasates and PMV-depleted releasates were prepared by differential centrifugation steps on days 0, 1, 5, and 7 of storage. Cytokine/chemokine release following PI treatment was analyzed by an antibody array, and results were verified by the enzyme-linked immunosorbent assay. PMVs were enumerated by CD41 labeling and flow cytometry. Wound scratch assays were performed using cultured Ea.hy926 cells exposed to the differently prepared releasates. Effects of releasates on the phosphorylation levels of kinases ERK and p38 expressed by endothelial cells were analyzed by immunoblot. RESULTS: Cytokine/chemokine assays identified a 2-fold increase in epidermal growth factor released from PCs treated with RF/UV light compared with control. PMV count increased ~100-fold following PI treatment. Unmodified releasates and PMV-depleted releasates displayed different contributions to the kinetics of endothelial cell wound closure. This observation was associated with an increased ERK versus unaltered p38 activation in the endothelial cells. CONCLUSION: This study identified an inhibitory impact of PMVs on endothelial cell migration/proliferation upon stimulation by released cytokines and PMVs from PLTs treated with RF/UV light for endothelial cell wound closure.

Pathogen reduction of whole blood: Supplementing fibrinogen partly corrects clot formation in a massive transfusion model.

BACKGROUND: The use of whole blood (WB) to treat trauma patients is becoming more common. Similar to the treatment of individual components, pathogen inactivation (PI) technologies are available to treat WB. The impact of PI on WB function is not well understood. This study investigated the impact of PI of WB with riboflavin/ultraviolet (UV) light on its hemostatic function by modeling transfusion scenarios for trauma patients and assessing transfusion efficacy by rotational thromboelastometry (ROTEM). As fibrinogen is affected by PI of WB, the effect of fibrinogen supplementation commonly used in trauma patients was also analyzed in this model. STUDY DESIGN AND METHODS: Trauma transfusion scenarios were simulated by mixing untreated WB or WB treated with the Mirasol PI technology (riboflavin/UV) in different ratios with hemodiluted blood, and the thromboelasticity was monitored by ROTEM. The impact of supplementation with the fibrinogen concentrate RiaSTAP was investigated in this model. RESULTS: Pathogen-inactivated WB (PI-WB) showed decreased activity in the hemostatic profile compared to the untreated control. Hemodiluted blood at a hematocrit (hct) of 20%, which was reconstituted with PI-WB or untreated WB, exhibited increased alpha values, maximum clot firmness, and clot formation time. Simulating transfusion scenarios by blood replacement with PI-WB resulted in a significant difference in ROTEM parameters between reconstituted PI-treated and -untreated WB (p ≥ .05). The effect of PI treatment waned when PI-WB was enriched with fibrinogen. CONCLUSION: ROTEM investigations suggest that PI treatment has a negative impact on WB clot formation unless fibrinogen supplementation is used.

Antioxidant power measurement in platelet concentrates treated by two pathogen inactivation systems in different blood centres.

BACKGROUND AND OBJECTIVES: The antioxidant power measurement can be useful to validate the execution of the pathogen inactivation treatment of platelet concentrates. The aim of this study is to evaluate the technology on different blood preparations including INTERCEPT and Mirasol treatments that are in routine use in Belgium and Luxemburg. MATERIALS AND METHODS: The antioxidant power measurement was tested on 78 apheresis platelet concentrates and 54 pools of buffy-coats-derived platelet concentrates before and after INTERCEPT treatment. In addition, 100 Reveos platelet pools were tested before and after Mirasol treatment. The antioxidant power was quantified electrochemically using disposable devices and was expressed as equivalent ascorbic acid concentration. RESULTS: Mean results for apheresis platelet concentrates were of 90 ± 14 and 35 ± 10 µmol/l eq. ascorbic acid before and after INTERCEPT treatment, respectively. The mean results for pools of buffy-coats-derived platelet concentrates were of 81 ± 10 and 29 ± 4 eq. µmol/l ascorbic acid before and after INTERCEPT treatment, respectively. For buffy-coats-derived platelet concentrates treated by Mirasol technology, the mean results were of 98 ± 11 and 32 ± 10 µmol/l eq. ascorbic acid before and after illumination, respectively. CONCLUSION: The antioxidant power significantly decreases with pathogen inactivation treatments for platelet concentrates treated by INTERCEPT or Mirasol technologies.