Impact of glucose and acetate on the characteristics of the platelet storage lesion in platelets suspended in additive solutions with minimal plasma

Indocyanine Green-Labeled Platelets for Survival and Recovery Studies

Introduction

Before being implemented in daily clinical routine, new production strategies for platelet concentrates (PCs) must be validated for their efficacy. Besides in vitro testing, the establishment of new methods requires the labeling of platelets for in vivo studies of platelets' survival and recovery. Indocyanine green (ICG) is a Food and Drug Administration-approved near-infrared (NIR) fluorescent dye for diagnostic use in vivo, suitable for non-radioactive direct cell labeling of platelets.

Methods

Platelets from PCs in storage solutions with different plasma concentrations were labeled with ICG up to concentrations of 200 μm. Whole blood (WB) was used as an ex vivo matrix to monitor the labeling stability of ICG-labeled platelets. The impact of labeling processes was assessed by the quantification of CD62P expression and PAC-1 binding as platelet function markers. Platelet aggregation was analyzed by light transmission aggregometry. ICG-labeling efficiency and stability of platelets were determined by flow cytometry.

Results

Platelets from PCs could be successfully labeled with 10 μm ICG after 1 and 4 days of storage. The best labeling efficiency of 99.8% ± 0.1% (immediately after labeling) and 81% ± 6.2% (after 24 h incubation with WB) was achieved by plasma replacement by 100% platelet additive solution for the labeling process. Since the washing process slightly impaired platelet function, ICG labeling itself did not affect platelets. Immediately after the ICG-labeling process, plasma was re-added, resulting in a recovered platelet function.

Conclusion

We developed a Good Manufacturing Practice compatible protocol for ICG fluorescent platelet labeling suitable for survival and recovery studies in vivo as a non-radioactive labeling alternative.

In Vitro Comparative Study of Platelets Treated with Two Pathogen-Inactivation Methods to Extend Shelf Life to 7 Days

Background and Objectives: Since 2015, platelet products have been pathogen-inactivated (PI) at the Luxemburgish Red Cross (LRC) using Riboflavin and UV light (RF-PI). As the LRC should respond to hospital needs at any time, platelet production exceeds the demand, generating a discard rate of 18%. To reduce this, we consider the extension of storage time from 5 to 7 days. This study’s objective was to evaluate the in vitro 7-day platelet-storage quality, comparing two PI technologies, RF-PI and amotosalen/UVA light (AM-PI), for platelet pools from whole-blood donations (PPCs) and apheresis platelets collected from single apheresis donation (APCs). Materials and Methods: For each product type, 6 double-platelet concentrates were prepared and divided into 2 units; one was treated with RF-PI and the other by AM-PI. In vitro platelet-quality parameters were tested pre- and post-PI, at days 5 and 7. Results: Treatment and storage lesions were observed in PPCs and APCs with both PI methods. We found a higher rate of lactate increase and glucose depletion, suggesting a stronger stimulation of the glycolytic pathway, a higher Annexin V binding, and a loss of swirling in the RF-PI-treated units from day 5. The platelet loss was significantly higher in the AM-PI compared with the RF-PI units. Conclusions: Results suggest that RF-PI treatment has a higher deleterious impact on in vitro platelet quality compared to AM-PI, but we observed higher loss of platelets with AM-PI due to the post-illumination amotosalen adsorption step. If 7-day storage is needed, it can only be achieved with AM-PI, based on our quality criteria.

Platelet transfusion for cancer secondary thrombocytopenia: Platelet and cancer cell interaction

Chemoradiotherapy and autoimmune disorder often lead to secondary thrombocytopenia in cancer patients, and thus, platelet transfusion is needed to stop or prevent bleeding. However, the effect of platelet transfusion remains controversial for the lack of agreement on transfusion strategies. Before being transfused, platelets are stored in blood banks, and their activation is usually stimulated. Increasing evidence shows activated platelets may promote metastasis and the proliferation of cancer cells, while cancer cells also induce platelet activation. Such a vicious cycle of interaction between activated platelets and cancer cells is harmful for the prognosis of cancer patients, which results in an increased tumor recurrence rate and decreased five-year survival rate. Therefore, it is important to explore platelet transfusion strategies, summarize mechanisms of interaction between platelets and tumor cells, and carefully evaluate the pros and cons of platelet transfusion for better treatment and prognosis for patients with cancer with secondary thrombocytopenia.

MicroRNAs as a Potential Quality Measurement Tool of Platelet Concentrate Stored in Blood Banks-A Review

BACKGROUND

Platelet concentrate (PC) is one of the main products used in a therapeutic transfusion. This blood component requires special storage at blood banks, however, even under good storage conditions, modifications or degradations may occur and are known as platelet storage lesions.

METHODS

This research was performed on scientific citation databases PubMed/Medline, ScienceDirect, and Web of Science, for publications containing platelet storage lesions. The results obtained mainly reveal the clinical applicability of miRNAs as biomarkers of storage injury and as useful tools for a problem affecting public and private health, the lack of PC bags in countries with few blood donors. The major studies listed in this review identified miRNAs associated with important platelet functions that are relevant in clinical practice as quality biomarkers of PC, such as miR-223, miR-126, miR-10a, miR-150, miR-16, miR-21, miR-326, miR-495, let-7b, let-7c, let-7e, miR-107, miR-10b, miR-145, miR-155, miR-17, miR-191, miR-197, miR-200b, miR-24, miR-331, miR-376. These miRNAs can be used in blood banks to identify platelet injury in PC bags.

CONCLUSION

The studies described in this review relate the functions of miRNAs with molecular mechanisms that result in functional platelet differences, such as apoptosis. Thus, miRNA profiles can be used to measure the quality of storage PC for more than 5 days, identify bags with platelet injury, and distinguish those with functional platelets.

L-Carnitine as an additive in Tyrode's buffer during platelet storage

: Platelets are stored at 22-24°C for 5 days, with gentle agitation. Platelet storage lesion decreases efficacy and safety of stored platelets. L-Carnitine is a nonessential amino acid. Its interference with arachidonic acid metabolism affects platelet functions and oxidative stress. Hence, our study focuses on the use of L-carnitine in storage solution and investigates its influence on platelet functions and oxidative stress. Platelets isolated from 4-month-old male Wistar rats were stored with and without L-carnitine (10, 50 and 100 mmol/l) at 22°C for 12 days. Various markers were analyzed on days 0, 4, 8 and 12. Aggregation with collagen decreased in LC100 (day 12), whereas adenosine triphosphate secretion increased in all L-carnitine groups. Glucose consumption was less in L-carnitine groups and pH was maintained at 7.4 in LC50 (day 8). Conjugate dienes (day 4) and thiobarbituric acid reactive substances (day 8) increased in LC10 and LC100. Protein carbonyls were maintained in L-carnitine groups. Catalase activity and total antioxidant capacity increased gradually. L-Carnitine proved to be beneficial in platelet storage solution. There was improvement in platelet metabolism, decrements in lipid peroxidation and elevations in total antioxidant capacity up to 12 days. However, pH results emphasize that platelets with L-carnitine (50 mmol/l) could be stored up to 8 days. Therefore, Tyrode's buffer with L-carnitine can be an effective storage solution for extended platelet storage. This study contributes towards the development of better storage solutions for platelets.

Platelet storage in more than 90% additive solution containing glucose and bicarbonate has the potential to increase shelf life

BACKGROUND

Platelet concentrates (PCs) suspended in more than 90% additive solution (AS) are recommended for patients with reactions to platelets stored in plasma. Next-generation AS containing glucose and bicarbonate might enable storage of these PCs for longer than those in current-generation AS, which was therefore evaluated in this study.

STUDY DESIGN AND METHODS

Five buffy coat or apheresis-derived PCs were pooled and split into identical units. All units except the control were centrifuged, the plasma removed and replaced with AS (SSP+, PAS-5, or PAS-G), or resuspended in the same plasma and sampled 96 hours after resuspension for analysis.

RESULTS

Plasma carryover was less than 10%, total protein less than 1 g/unit, and immunoglobulin A levels lower than 0.1 mg/mL for all PCs in AS. The pH of all the platelets during storage was higher than 6.4. PAS containing glucose maintained superior in vitro platelet function during storage compared with those resuspended in SSP+. Compared with storage in SSP+, storage in PAS-5 or PAS-G resulted in better preservation of platelet adenosine triphosphate and hypotonic shock response, lower annexin V binding, and improved mitochondrial membrane potential.

CONCLUSION

Platelets resuspended in PAS-5 and PAS-G maintained in vitro function and metabolism during storage compared with SSP+ platelets. Elevated platelet metabolic activity was noticed in PAS-G, and higher platelet activation was detected with PAS-5. Platelets resuspended in PAS containing glucose has the potential to increase the shelf life of PC in more than 90% AS.

Consequences of Transfusing Blood Components in Patients With Trauma: A Conceptual Model

Transfusion of blood components is often required in resuscitation of patients with major trauma. Packed red blood cells and platelets break down and undergo chemical changes during storage (known as the storage lesion) that lead to an inflammatory response once the blood components are transfused to patients. Although some evidence supports a detrimental association between transfusion and a patient's outcome, the mechanisms connecting transfusion of stored components to outcomes remain unclear. The purpose of this review is to provide critical care nurses with a conceptual model to facilitate understanding of the relationship between the storage lesion and patients' outcomes after trauma; outcomes related to trauma, hemorrhage, and blood component transfusion are grouped according to those occurring in the short-term (≤30 days) and the long-term (>30 days). Complete understanding of these clinical implications is critical for practitioners in evaluating and treating patients given transfusions after traumatic injury.

Quality Assessment of Established and Emerging Blood Components for Transfusion

Blood is donated either as whole blood, with subsequent component processing, or through the use of apheresis devices that extract one or more components and return the rest of the donation to the donor. Blood component therapy supplanted whole blood transfusion in industrialized countries in the middle of the twentieth century and remains the standard of care for the majority of patients receiving a transfusion. Traditionally, blood has been processed into three main blood products: red blood cell concentrates; platelet concentrates; and transfusable plasma. Ensuring that these products are of high quality and that they deliver their intended benefits to patients throughout their shelf-life is a complex task. Further complexity has been added with the development of products stored under nonstandard conditions or subjected to additional manufacturing steps (e.g., cryopreserved platelets, irradiated red cells, and lyophilized plasma). Here we review established and emerging methodologies for assessing blood product quality and address controversies and uncertainties in this thriving and active field of investigation.

Value of calcium and phosphate in a bicarbonate-containing platelet additive solution with low plasma levels in maintaining key in vitro platelet storage parameters

BACKGROUND

Use of recently developed platelet (PLT) additive solutions (PAS) with 5% plasma levels may reduce the frequency and/or severity of transfusion reactions attributed to plasma. PLTs suspended in bicarbonate-containing PAS-5 with 5% plasma levels can maintain key PLT parameters during 7-day storage. This study evaluates the role of calcium and phosphate, as constituents of PAS-5, in maintaining PLT parameters.

STUDY DESIGN AND METHODS

An Amicus apheresis PLT unit (n = 13) was equally divided into four 60-mL aliquots in CF-250 polyolefin bags. Four different formulations of PAS-5 were prepared: PAS-5, PAS-5 without phosphate (-PO₄ ), PAS-5 without calcium (-Ca), and PAS-5 without Ca and phosphate (-Ca/-PO₄ ). PLTs were centrifuged, and the supernatant was expressed and replaced with the respective PAS, yielding PLTs suspended in 95% PAS and 5% plasma. PLTs were stored at 20 to 24ºC with agitation for 7 days. PLT in vitro parameters were evaluated on Days 1, 5, and 7.

RESULTS

In PLT PAS-5 aliquots, pH levels were maintained better compared with those in -Ca and -Ca/-PO₄ aliquots. Glycolysis was greater in -Ca and -Ca/-PO₄ PLT aliquots compared with PAS-5 aliquots. Hypotonic stress response and morphology were less and p-selectin (CD62P) binding was greater in -Ca/-PO₄ PLT aliquots. The accumulation of reactive oxygen species was greater in -Ca/-PO₄ PLTs. Phosphorylation of p38 mitogen-activated protein kinase (MAPK) was greater in -Ca and -Ca/-PO₄ PLT aliquots during storage.

CONCLUSION

The removal of calcium and phosphate from PAS-5 leads to the activation of p38 MAPK and deterioration of key PLT storage parameters.

Influence of Oxidative Stress on Stored Platelets

Platelet storage and its availability for transfusion are limited to 5-6 days. Oxidative stress (OS) is one of the causes for reduced efficacy and shelf-life of platelets. The studies on platelet storage have focused on improving the storage conditions by altering platelet storage solutions, temperature, and materials. Nevertheless, the role of OS on platelet survival during storage is still unclear. Hence, this study was conducted to investigate the influence of storage on platelets. Platelets were stored for 12 days at 22°C. OS markers such as aggregation, superoxides, reactive oxygen species, glucose, pH, lipid peroxidation, protein oxidation, and antioxidant enzymes were assessed. OS increased during storage as indicated by increments in aggregation, superoxides, pH, conjugate dienes, and superoxide dismutase and decrements in glucose and catalase. Thus, platelets could endure OS till 6 days during storage, due to the antioxidant defense system. An evident increase in OS was observed from day 8 of storage, which can diminish the platelet efficacy. The present study provides an insight into the gradual changes occurring during platelet storage. This lays the foundation towards new possibilities of employing various antioxidants as additives in storage solutions.

Novel platelet storage conditions: additive solutions, gas, and cold

PURPOSE OF REVIEW

Platelets are a frequently requested blood product today and are often in limited supply because of a shelf life of 5-7 days, depending on the country. Room temperature storage is associated with an increased risk of transfusion-transmitted infection. Plasma used for platelet storage is unavailable for other uses, and allogeneic plasma carries with it risks for adverse transfusion reactions. This review looks at recent activities evaluating alternative conditions for the storage of platelets.

RECENT FINDINGS

New-generation platelet additive solutions are being evaluated and applied as a strategy to reduce the volume of allogeneic plasma transfused and to support storage following pathogen reduction treatments. There is a renewed interest in refrigerator temperature and frozen storage of platelets to improve availability, to reduce septic transfusion risk, and to enhance hemostatic efficacy in the bleeding patient.

SUMMARY

Use of platelet additive solutions has been shown to reduce the incidence of allergic and nonhemolytic febrile transfusion reactions in two large studies. Results of ongoing research and new clinical trials in cold storage methods will be forthcoming and may present solutions for platelet availability problems and new choices for therapeutic transfusion of the bleeding patient.

Metabolomic analysis of platelets during storage: a comparison between apheresis- and buffy coat-derived platelet concentrates

BACKGROUND

Platelet concentrates (PCs) can be prepared using three methods: platelet (PLT)-rich plasma, apheresis, and buffy coat. The aim of this study was to obtain a comprehensive data set that describes metabolism of buffy coat-derived PLTs during storage and to compare it with a previously published parallel data set obtained for apheresis-derived PLTs.

STUDY DESIGN AND METHODS

During storage we measured more than 150 variables in 8 PLT units, prepared by the buffy coat method. Samples were collected at seven different time points resulting in a data set containing more than 8000 measurements. This data set was obtained by combining a series of standard quality control assays to monitor the quality of stored PLTs and a deep coverage metabolomics study using liquid chromatography coupled with mass spectrometry.

RESULTS

Stored PLTs showed a distinct metabolic transition occurring 4 days after their collection. The transition was evident in PLT produced by both production methods. Apheresis-derived PLTs showed a clearer phenotype of PLT activation during early days of storage. The activated phenotype of apheresis PLTs was accompanied by a higher metabolic activity, especially related to glycolysis and the tricarboxylic acid cycle. Moreover, the extent of the activation differed between bags resulting in interbag variability in the storage lesion of apheresis-prepared PLTs. This may be related to donor-related polymorphism.

CONCLUSION

This study demonstrated two discrete metabolic phenotypes in stored PLTs prepared with both apheresis and buffy coat methods. PLT activation occurs during the first metabolic phenotype and might lead to a low reproducibility of the apheresis PCs.

Platelet storage media

Present platelet storage media often designated platelet additive solutions (PAS) basically contain acetate, citrate and phosphate and recently also potassium and magnesium. However, there seems to be an increasing interest in developing PASs that can be used also after further reduction of residual plasma content below 15-20% plasma. Inclusion of glucose but also calcium and bicarbonate in such solutions have been suggested to improve platelet (PLT) storage, especially when plasma content is reduced to very low levels. Results from a limited number of studies using novel PAS alternatives have been presented during the last years, such as InterSol-G, PAS-5, M-sol, PAS-G and SAS. Most of them are experimental solutions. The combined results presented in those studies suggest that presence of glucose may be necessary during PLT storage, primarily to maintain ATP at acceptable levels. At plasma inclusion below 15-20%, the content of glucose will generally be too low to support PLT metabolism for more than a few days making glucose addition in PAS necessary. Significant effects associated with presence of calcium was observed in PLTs stored in PAS with 5% inclusion but not with 20-35% plasma inclusion, suggesting that the content of plasma could be of importance. Bicarbonate only seems to be of importance for pH regulation, primarily when plasma inclusion is reduced to about 5%. Reduction in rate of glycolysis was observed in some PAS alternatives containing potassium and magnesium but not in others. Differences in pH or in concentrations of the various compounds included in PAS may be possible explanations. Additionally, novel PAS containing glucose, calcium and bicarbonate does not seem to be associated with improved in vitro results as compared to SSP+ or CompoSol when PLTs are stored with 35% plasma inclusion. The results would then also suggest that excess of glucose in novel PAS environment may not be associated with additional positive effects on PLT metabolism. This review is based on the few publications on novel PAS available, and additional studies would be needed in the future.

Comprehensive metabolomic study of platelets reveals the expression of discrete metabolic phenotypes during storage

BACKGROUND

Platelet (PLT) concentrates are routinely stored for 5 to 7 days. During storage they exhibit what has been termed PLT storage lesion (PSL), which is evident by a loss of hemostatic function when transfused into patients. The overall goal of this study was to obtain a comprehensive data set describing PLT metabolism during storage.

STUDY DESIGN AND METHODS

The experimental approach adopted to achieve this goal combined a series of standard assays to monitor the quality of stored PLTs and a deep-coverage metabolomics study using liquid chromatography coupled with mass spectrometry performed on both the extracellular and the intracellular environments. During storage we measured 174 different variables in 6 PLT units, collected by apheresis. Samples were collected at eight different time points resulting in a data set containing more than 8000 measurements.

RESULTS

Stored PLTs did not undergo a monotonic decay, but experienced systematic changes in metabolism reflected in three discrete metabolic phenotypes: The first (Days 0-3) was associated with active glycolysis, pentose phosphate pathway, and glutathione metabolism and down regulation of tricarboxylic acid (TCA) cycle. The second (Days 4-6) was associated with a more active TCA cycle as well as increased purine metabolism. A third metabolic phenotype of less clinical relevance (Days 7-10) was associated with a faster decay of cellular metabolism.

CONCLUSION

PSL is not associated with a linear decay of metabolism, but rather with successive metabolic shifts. These findings may give new insight into the mechanisms underlying PSL and encourage the deployment of systems biology methods to PSL.

Evaluation of in vitro storage properties of apheresis platelets suspended in a bicarbonate-containing additive solution with low levels of plasma and stored with a 24-hour interruption of agitation

BACKGROUND AND OBJECTIVES

PLT additive solutions (PAS) are useful for reducing the frequency and/or severity of plasma-associated transfusion reactions. A new PAS solution, PAS-5, containing 5% plasma, maintains in vitro PLT properties during 7-day storage. Periods with interruption of agitation (IA) ≤24 h routinely occur during PLT shipment and do not usually compromise platelet quality. The aim of the study was to evaluate the properties of PLTs stored for 7 days in 95% PAS-5/5% plasma subjected to a 24-h IA.

MATERIALS AND METHODS

Double apheresis Amicus units (n = 12) were collected using a manual PAS-5 addition to hyperconcentrated PLTs. PLT units were equally divided in two containers. Control and test PLTs were stored with continuous agitation at 20-24°C except for 24-h IA period for test units between days 2-3.

RESULTS

During storage, levels of glucose, lactate, mitochondrial membrane potential and aggregation significantly differed in test units compared to those of control. The pH levels of test PLTs were less than those of control units with 7/12 test units having pHs <6·2 on Day 7 compared to 1/12 control units. Morphology score, GP1bα expression, ESC values, superoxide production were also less, and activation was greater in test PLTs than those of control. All other parameters were similar between test and control units.

CONCLUSION

PLTs stored in PAS-5 solution containing 5% plasma with a 24-h IA results in marked decrements in many in vitro PLT quality parameters during 7-day storage.