Annexin V and platelet antigen expression is not altered during storage of platelet concentrates obtained with the AMICUS cell separator.

During storage of platelet concentrate the so-called "storage lesion" occurs. During this time, platelets loose their morphological and functional capacities that are necessary for proper in vivo efficacy following transfusion. Annexin V represents a marker for apoptosis. In this study, Annexin V and additional antigens were analyzed by flow cytometry. Platelet concentrates were obtained with a new cell separator (AMICUS Separator, Fenwal). Following apheresis, platelet units were stored for an experimentally prolonged time of seven days. Daily aliquots of the platelet-rich plasma were obtained to measure Annexin V and platelet antigens CD62p, CD63, CD41a, CD42b, and the binding of fibrinogen. All analyses were performed using flow cytometry. During storage, no significant changes in mean channel fluorescence intensity (MCFI) of CD41a (P = 0.99) and CD42b (P = 0.29), percentage of CD62p+ and CD63+ platelets (P = 0.23 for CD62p; P = 0.52 for CD63), and the binding of fibrinogen to platelets occurred (P = 0.85). Also, the expression of Annexin V remained constant with no significant change (P = 0.36). This study shows that antigens of platelets, obtained with the AMICUS cell separator are well preserved during storage. Regarding Annexin V, no obvious signs of apoptosis can be detected by flow cytometry. These findings demonstrate the high degree of biocompatibility of the apheresis device and storage container.     

糖基化修饰血小板冷藏稳定性研究

本研究旨在观察尿苷二磷酸半乳糖（UDP-6ai）糖基化修饰人血小板的稳定性、理化指标及体外功能变化。实验分为室温对照组、冷藏对照组以及修饰组（U＋4组和4＋U组）。机采人浓缩血小板悬液，4℃保存前或后添加适量UDP—Gal，进行糖基化修饰，分别于0、1、3、5、7、14天，通过荧光标记识别血小板膜糖蛋白末端半乳糖残基的凝集素（FITC—RCAⅠ）检测糖基化修饰效果；pH计检测血小板悬液pH值；血细胞计数仪检测血小板平均体积；比浊法测定血小板聚集率；流式细胞术检测血小板活化标志CD62P、血小板膜蛋白CD42b及Ps的表达。结果表明：保存14天时，修饰组血小板RCAⅠ结合率是室温组的5—6倍；修饰组血小板悬液pH低于室温组，但二者之间无显著性差异（P〉0．05）；保存14天时室温组和修饰组血小板平均体积分别为10．6±1．9fL和11．14±1．1fL，二者之间无显著性差异（p〉0．05）；各组体外聚集活性在保存过程中均逐渐下降，但修饰组优于室温组（p〈0．05）；流式检测结果显示，保存1—5天修饰组CD62P、CD42b和Ps表达的阳性率与新鲜血小板无显著性差异（P〉0．05），但保存14天时，CD62P和Ps表达的阳性率升高，CD42b表达的阳性率降低，与新鲜血小板相比差异极显著（p〈0．01）。结论：在修饰血小板保存过程中，糖基化修饰的效果稳定，修饰血小板的pH和平均体积均处于正常值范围之内，聚集活性良好，优于室温保存组，但在保存5天后表现出不同程度的活化。     

Cryopreservation of apheresis platelets treated with riboflavin and UV light

BackgroundPathogen reduction technology (PRT) is increasingly used in the preparation of platelets for therapeutic transfusion. As the Czech Republic considers PRT, we asked what effects PRT may have on the recovery and function of platelets after cryopreservation (CP), which we use in both military and civilian blood settings.Study design and methods16 Group O apheresis platelets units were treated with PRT (Mirasol, Terumo BCT, USA) before freezing; 15 similarly collected units were frozen without PRT as controls. All units were processed with 5–6% DMSO, frozen at − 80 °C, stored > 14 days, and reconstituted in thawed AB plasma. After reconstitution, all units were assessed for: platelet count, mean platelet volume (MPV), platelet recovery, thromboelastography, thrombin generation time, endogenous thrombin potential (ETP), glucose, lactate, pH, pO2, pCO2, HCO3, CD41, CD42b, CD62, Annexin V, CCL5, CD62P, and aggregates > 2 mm and selected units for Kunicki score.ResultsPRT treated platelet units had lower platelet number (247 vs 278 ×10⁹/U), reduced thromboelastographic MA (38 vs 62 mm) and demonstrated aggregates compared to untreated platelets. Plasma coagulation functions were largely unchanged.ConclusionsSamples from PRT units showed reduced platelet number, reduced function greater than the reduced number would cause, and aggregates. While the platelet numbers are sufficient to meet the European standard, marked platelets activation with weak clot strength suggest reduced effectiveness.     

血小板保存3天后再冷冻保存的实验研究及临床应用

本研究探讨血小板常温保存3天后再进行-80℃冰箱内冷冻保存及临床应用的可行性。对当天冷冻和保存3天后再冷冻血小板进行了计数，并检测聚集力、黏附力以及CD62p的表达，并通过可对比性病例观察保存3天后再冷冻与当天冷冻血小板，临床应用的可能性。结果表明：在保存期3天之内血小板数量、低渗性休克反应、黏附功能无显著差异性改变（P〉0．05），但聚集功能和CD62p的表达率的变化有显著性差异（P〈0．05）。当天保存并冷冻的血小板与保存3天后再冷冻的血小板各项指标的变化都无显著性差异。CD62p的再表达率（CD62p凝血酶激活后阳性率-CD62p激活前的阳性率）也无显著性差异，分别是51．1±4．5和51．1±4．4（P〉0．05）。临床应用当天冷冻和保存3天后再冷冻血小板的CCI值分别是48％和49％，无显著性差异（P〉0．05）。结论：血小板保存3天后可以再-80℃冷冻保存，其临床应用效果与当天冷冻血小板比较后无明显差异。     

Storage of single donor platelet concentrates: Paired comparison of storage as single or double concentrates

Modern cell separators allow the collection of two plateletpheresis concentrates (PCs) at one session. This study evaluates the quality of PCs stored as double concentrates in standard storage containers of two manufacturers. We collected 20 PCs that contained 4.5 × 10¹¹ platelets in 375 ml plasma (10 using the COBE Spectra and 10 using the Fresenius AS.TEC 204 with 500 ml bags) that were split into one unit of 3.0 × 10¹¹ platelets in 250 ml (3.0‐PC) and one of 1.5 × 10¹¹ platelets in 125 ml (1.5‐PC). Storage of one 3.0‐PC per bag of a two‐bag system corresponded to storage conditions for double PCs and storage of one 1.5‐PC per bag to storage conditions of single PCs. Cell counts, blood gas analysis, glucose and lactate levels, platelet aggregation, and activation and plasma levels of β‐ thromboglobulin (β‐TG) and complement factor 3a (C3a) were measured before storage and again on days 3 and 5. COBE 3.0‐PCs demonstrated less pH rise, lactate production, CD 62P expression and β‐TG plasma levels, and better aggregability after storage than COBE 1.5‐PCs. Fresenius 1.5‐PCs had similar platelet quality to COBE 3.0‐PCs. Fresenius 3.0‐PCs showed a fall of pH (day 5: 6.22 ± 0.56), the highest amount of anaerobic glycolysis compared to all other storage conditions investigated, high CD 62P‐ expression and β‐TG plasma levels, and impaired aggregability on days 3 and 5. The highest C3a levels were found in COBE 1.5‐PCs. 3.0 × 10¹¹ platelets in 250 ml plasma should be stored either in one bag of the COBE system or in two 500 ml bags of the Fresenius system. The COBE two‐bag system allows the storage of two PCs without loss of platelet quality. Two PCs should not be stored in the Fresenius C4L 500 ml storage containers. J. Clin. Apheresis. 16:148‐154, 2000. © 2001 Wiley‐Liss, Inc.     

Comparison between a new PVC platelet storage container (UPX80) and a polyolefin container

During storage of platelet concentrates (PCs), the quality of the platelets deteriorates gradually, partially dependent on gas exchange. UPX80 (JMS, Japan) 1-L platelet storage PVC containers with increased gas transport capacity were compared with 1- and 1. 5-L polyolefin (PO) containers (NPBI, the Netherlands) with filtered PCs stored either in GAC (gluconate-acetate-citrate, < 10% plasma) or in plasma, for 8 days. In total 32 PCs were made (260-330 x 109 platelets per concentrate), equally divided over different bags and storage media. During storage, gas exchange, metabolic, physical and activation parameters were measured. No consistent differences for all parameters were observed between UPX80 and PO containers (1-L or 1.5-L). Blood gas parameters indicated better gas exchange for UPX80 containers compared with PO containers. Good morphology was observed in UPX80 and metabolic functions were not significantly different compared with PO containers. During prolonged storage (after day 6), some significant differences in CD62P and CD63 expression were found, indicating a higher degree of platelet activation in UPX80 containers, especially in GAC. UPX80 PC containers are suitable for storage of PCs. Although in UPX80 better gas exchange is demonstrated, as compared with PO containers, this does not improve the platelet quality during storage for 6 days, indicating that gas exchange above the level of PO containers has no effect on the switch to aerobic metabolism in platelets.     

Autoapheresis and intraoperative blood salvage in oncologic surgery

Platelet activation occurs during the collection, processing and storage of platelet concentrates. The effect of the platelet activation on the functional state of stored platelets remains however undefined. We employed flow cytometric analysis to evaluate the extent of platelet activation and the physiological response to thrombin stimulation of platelets stored for up to five days under routine blood bank conditions. Platelet surface expression of the activation markers CD62 and CD63 was examined, along with modulation of platelet membrane glycoproteins (GP) Ib and IIbIIIa. Platelet dense granule content was determined using a mepacrine uptake assay and the extent of platelet microparticle generation was quantified. Thirteen random-donor platelet concentrates prepared under routine conditions by a platelet-rich-plasma protocol were examined. Platelets were found to be activated following preparation on day 1. Although a gradual increase was seen with increasing storage time, this was not statistically significant for CD62 or CD63 expression, GPIIbIIIa or GPIb modulation or dense granule release; the generation of platelet microparticles did, however, increase with increasing storage time. The characteristic increase in surface expression of CD62, CD63 and GPIIbIIIa and decrease in GPIb and dense granule content in response to thrombin stimulation was observed with all concentrates, but these measures of platelet functional reserve showed decreasing platelet function with increasing storage time. The results indicate that platelets are activated by day 1, likely as a consequence of manipulation during collection and processing, but are not further progressively activated with increasing storage time; they do, however, become relatively hypofunctional with increasing storage.     

Effects of prestorage white cell reduction on platelet aggregate formation and the activation state of platelets and plasma enzyme systems

BACKGROUND: The introduction of prestorage white cell (WBC) reduction in random-donor platelet concentrates in Canada has increased the occurrence of particulate material in PCs. The effects of filtration on platelet activation state and the activation of plasma enzyme systems were assessed. STUDY DESIGN AND METHODS: Particulate material was examined by light microscopy, electron microscopy, protein electrophoresis, and biochemical analysis. Thirty PCs (10 unfiltered, 20 filtered) were examined during processing and 5-day storage for pH, platelet count and mean volume, morphology, activation marker expression, and hypotonic shock response. Complement activation, thrombin generation, and fibrinolysis were assessed by using specific enzyme immunoassays or chromogenic assays. RESULTS: By all analyses, the particulate material appeared to be platelet aggregates. Platelets exposed to WBC-reduction filters expressed a significantly higher level of activation markers CD62 and CD63, altered morphology, and increased platelet microparticles throughout the storage period than did unfiltered platelets. Complement activation at the C3 level was significantly increased in filtered units with little evidence of coagulation or fibrinolytic system activation. CONCLUSION: Exposure of platelets to filters during prestorage WBC reduction increased platelet activation and mildly increased complement activation over the levels during the storage period. These alterations can contribute to the formation of irreversible platelet aggregates during processing.     

Apoptotic activity in stored human platelets

BACKGROUND: Platelets possess some of the machinery required for apoptotic cell death. However, disruption of mitochondria function, implicated in several models of cell death, has not been extensively studied in platelets. Mitochondrial viability and several other measures of apoptotic death in stored and experimentally stressed platelets were evaluated. MATERIALS AND METHODS: Platelet mitochondrial transmembrane potentials (Deltapsim) were studied by staining platelets with JC-1, a dye that fluoresces at different wavelengths based on the state of mitochondrial polarization. Annexin V binding, a measure of phosphatidylserine (PS) exposure, and CD62P expression, an indicator of platelet activation, were determined by flow cytometry. Caspase-3 activity was measured with an enzyme assay and by Western blotting. Experimental platelet stressors included storage for 7 days, azide exposure, calcium ionophore stimulation, and plasma deprivation. RESULTS: As measured by flow cytometry, Deltapsim values were similar in freshly drawn platelets and in platelet concentrates stored for up to 7 days. However, compared to fresh platelets, stored platelet concentrates had significantly increased PS exposure (3.1 vs. 5.1%, p = 0.015), CD62P expression (6.5 vs. 13.5%, p = 0.0067), and caspase-3 activity. Azide exposure, which decreased ATP release 20 to 30 percent, did not affect the Deltapsim. Stressed platelets exhibited higher degrees of mitochondrial depolarization in response to calcium ionophore stimulation than platelets that were not stressed. Plasma deprivation also resulted in significant alterations in Deltapsim, PS exposure, and CD62P expression. CONCLUSIONS: Platelet mitochondria maintain Deltapsim when stored for up to 7 days under standard blood bank storage conditions. Therefore, changes in platelet mitochondria Deltapsim do not correlate with downstream markers of apoptotic death such as caspase activation and PS exposure.     

单独采集血小板和浓缩血小板在保存期中的活化情况

研究单独采集血小板 (单采血小板 )和浓缩血小板在保存期中的活化情况。用流式细胞术对这两种血小板的CD62 p和CD41表达量进行测定。结果表明 :在保存 0 ,1 ,3和 5天时 ,单采血小板的CD62 p阳性率和CD41的平均荧光强度分别为 (1 8 91± 6 2 5) % ,(1 9 48± 8 2 7) % ,(2 2 82± 6 0 6) % ,(56 71± 1 1 79) %及 (8 0 9±2 38) % ,(8 1 3± 2 45) % ,(8 44± 2 51 ) % ,(1 9 87± 6 1 3) % ,而浓缩血小板的分别为 (30 65± 1 2 33) % ,(31 46± 1 1 86) % ,(32 51± 1 3 0 5) % ,(63 55± 1 3 2 7) %及 (1 0 33± 4 37) % ,(1 1 0 9± 6 61 ) % ,(1 3 46± 9 69) % ,(2 4 41± 1 0 1 5) %。二项指标均随保存时间推移而上升。对这两种血小板的计数和 pH值测定显示 ,二者均随保存时间推移而下降。在保存 0 - 3天内两种血小板的计数 ,pH值 ,CD62 p和CD41表达量无显著差异。在第 5天血小板计数和pH值出现显著下降 (P <0 0 0 1 ) ;而CD62p和CD41表达量出现显著上升 (P <0 0 0 1 )。结论 :单采血小板优于浓缩血小板     

Platelet apoptosis and activation in platelet concentrates stored for up to 12 days in plasma or additive solution

Background: Several studies suggest that apoptosis of platelets occurs during storage of platelet concentrates (PC). We sought to determine whether storage of PC in additive solution alters levels of apoptosis during storage beyond the current shelf life (5–7 days). Study design and methods: Pooled buffy coat PC (n = 7) were prepared in either 100% plasma or 70% Composol and stored at 22 °C for 12 days. A third arm of the study stored PC in 100% plasma at 37 °C, which is thought to induce apoptosis. PC were tested for mitochrondrial membrane potential, annexin V binding, microparticles, caspase‐3/7 activity and decoy cell death receptor 2, as well as standard platelet quality tests. Results: Composol units remained ≥pH 6·88, with 36% lower lactate and higher pH vs plasma by day 12 (P < 0·001). Platelet function was better maintained, and activation and apoptotic markers tended to be lower in Composol units towards the end of storage. However, levels of all apoptosis markers assessed were not significantly different in units stored in Composol. Storage at 37 °C saw stronger correlation of apoptotic markers with standard quality tests compared to 22 °C, but loss of correlation of caspase‐3/7 activity with other apoptosis markers. Conclusion: We conclude that storage of platelets in 70% Composol vs 100% plasma does not increase the rate of platelet apoptosis. Our data agree with other studies suggesting that platelet apoptosis is sequential to high levels of activation, but share a significant degree of overlap.     

Progressive platelet activation with storage: evidence for shortened survival of activated platelets after transfusion

Platelets are known to become activated during storage, but it is unclear whether such activation affects recovery or survival after platelet concentrate (PC) transfusion. With the use of flow cytometry to determine the percentage of platelets expressing the alpha-granule membrane protein 140 (GMP-140), a known adhesive ligand appearing on the platelet surface after activation, several studies were conducted. These investigations evaluated 1) the occurrence of significant platelet activation over time in PCs (n = 46) stored under standard blood bank conditions; 2) the correlation between platelet activation and platelet recovery in normal subjects after PC storage (n = 12), as assessed by the recovery of Indium-labeled platelets; and 3) the recovery of activated and unactivated platelets in thrombocytopenic cancer patients transfused with standard PCs (n = 11). It was determined 1) that an increasing duration of storage of PC was associated with increasing platelet activation as measured by the percentage of platelets expressing GMP-140, progressing from a mean of 4 +/- 2 percent (SD) on the day of collection to a mean of 25 +/- 8 percent by 5 days of storage: 2) that, in normal subjects, posttransfusion recovery of autologous platelets stored for 2 to 4 days and then labeled with In111 was inversely correlated with the percentage of activated platelets in the transfused PC (r = -0.55, p = 0.05); and 3) that, when thrombocytopenic patients were transfused with standard PCs, the recovery of the activated platelets in the transfused PCs averaged only 38 +/- 15 percent of the number predicted by the absolute platelet increment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Platelet function testing during 5-day storage of single and random donor plateletpheresis.

Platelet concentrates are routinely manufactured from whole blood by differential centrifugation (random donor platelets-RDP) or by plateletpheresis (single donor platelets-SDP). These platelet concentrates have a storage period of 5 days and many different approaches exist to measure the condition of platelets during their storage. In this study, platelet aggregation testing using adenosine diphosphate (ADP) and collagen and flow cytometric platelet activation analysis using CD41 FITC and CD62 PE before and after ADP was performed on days 1, 3 and 5 of storage of platelet preparations. Thirty three RDPs, stored in Baxter and Kansuk blood bags and 18 SDPs stored in Fresenius blood bags were evaluated. In RDPs and in SDPs; ADP and collagen induced PA responses were decreased significantly on the 3rd and 5th days compared to 1st day. CD62 positive platelet percentage after ADP were decreased significantly on the 3rd and 5th days compared to the 1st day in Kansuk((R)) bags. Flow cytometric analysis revealed minor changes in CD41 expression after ADP on the 3rd day compared to 1st day and on the 5th day compared to 3rd day. Differences in CD62 positive platelet percentage were not significant between the RDPs and SDPs. Our results suggest that: (1) ADP and collagen induced PA responses decrease both in RDPs and SDPs during storage. (2) Flow cytometric analysis does not show major significant changes in platelet activation after ADP during storage. (3) Continous shaking on the agitator does not cause a significant change in CD62 positive platelet percentage during storage. (4) Platelet aggregation responses in RDPs stored in Baxter((R)) and Kansuk((R)) blood bags do not differ during storage.     

Hyperbaric treatment of platelets is comparable to cold storage alone over 14 days

Background

Platelets stored at room temperature (22–24°C) for transfusion purposes have a shelf life of 5–7 days, or 72 h when stored refrigerated (1–6°C). The limited shelf life of platelet products severely compromises platelet inventory. We hypothesized that cold storage of platelets in 100% plasma using xenon gas under high pressure would extend shelf life to 14 days.

Study Design and Methods

Double apheresis platelet units were collected and split equally between two bags. One unit was placed in a hyperbaric chamber, pressurized to 4 bars with a xenon/oxygen gas mixture, and placed in a refrigerator for 14 days (Xe). The remaining unit was aliquoted into mini-bags (10 ml) for storage at room temperature (RTP) or in cold (CSP). Samples were assayed on days 5 (RTP) or 14 (Xe and CSP) for count, metabolism, clot strength, platelet aggregation, and activation markers.

Results

The platelet count in Xe samples was lower than that of RTP but significantly higher than CSP. Despite similar levels of glucose and lactate, the pH of Xe samples was significantly lower than CSP. Glycoprotein expression was better preserved by Xe storage compared to CSP, but no differences in activation were observed. Thromboelastography and aggregometry results were comparable between all groups.

Discussion

Cold storage of platelets in plasma with hyperbaric xenon provides no significant improvement in platelet function over cold storage alone. The use of a hyperbaric chamber and the slow off-gassing of Xe-stored units complicate platelet storage and delivery logistics.     

Large platelets continue to circulate in an activated state after myocardial infarction

Abstract This study was intended to investigate the actual platelet activation status after an acute coronary event. The activation status of circulating platelets was assayed directly by measuring the membrane activation markers CD62 and CD63 with the Düssel-dorf III flow cytometry test in 22 patients with the diagnosis of acute myocardial infarction during the 48-h observation period following the acute event. The number of activated, marker-positive sample platelets was significantly increased in the post-MI patients: CD62: 5·8%× 2·25^±1 vs. 3·5%× 2·32^±1, P≤ 0·05; CD63: 18·7%× 1·77^±1 vs. 4·6%× 2·16^±1, P≤ 0·00·1. The platelet volume and count were concomitantly increased (12·1 ± 2·4 fl/ 236 ± 90 times 10³μl^-1 compared to 8·3 ± 1·6 fl/187 ± 42 times 10³μl^-1) in the control group. Particularly large platelets were identified as being activated documented by the exponential increase in the difference in CD63-binding sites per sample platelet above the 90%-percentile and below the 10%-percentile of the volume distribution: Δ+ 1341 ± 903 (MI patients) vs. Δ+ 276 ± 126 (controls), P≤ 0·00·1. Significant creatine kinase elevation and decrease in platelet count was found in the non-survivor subset (n= 5). We conclude that predominantly large platelets continue to circulate in an activated state after MI. This study provides direct evidence that the assumption of an increased thrombotic potential becomes operative in vivo in MI patients. Besides CK elevation and decrease in platelet count this might possibly constitute a prognostic factor for the short-term outcome of the patients.     

TEG技术在血小板保存过程中功能评价的应用研究

本研究旨在通过血栓弹力图（thmmbelastography，TEG）技术探讨血小板保存过程中功能的变化。随机选择各项指标均符合国家标准的单供者机采血小板12个单位并在（22±2）℃条件下振荡保存。分别在保存1、2、3、4、5天检测血栓弹力图参数，包括反应时间（R）、凝血时间（K）、α角（ANG）和最大振幅（MA），同时检测血小板计数、平均血小板体积、低渗休克反应（HSR）水平、CD62p阳性率及凝血酶激活CD62p再表达率的变化，综合评价血小板保存过程中体外功能的变化情况。结果显示：平均血小板体积随保存时间延长而轻度增大，但无统计学差异（p〉0．05）；血小板膜表面CD62p表达率随保存时间延长而显著升高（P〈0．01）；凝血酶激活后CD62p再表达率随保存时间的延长而显著下降（p〈0．01）；血小板低渗休克反应水平在1-5天无明显变化（P〉0.05）；R值随保存时间延长而明显延长（P〈0．01），K值无明显变化（P〉0.05），α角虽呈轻度下降趋势，但无显著差异（P〉0．05）；MA值在保存1-4天无显著变化，保存5天时仅有轻度下降（P〈0．05）。结论：虽然血小板随保存时间延长激活率明显升高，但反映血小板综合凝血功能的最大振幅（MA值）和HSR水平在整个保存期内并无显著变化，说明保存期末的血小板仍然具有良好的止血功能；血栓弹力图参数MA值可以作为一项重要指标用于血小板保存过程中的功能评价。     

Quality of irradiated and non-irradiated plateletpheresis concentrates stored in platelet additive solution

Introduction

Platelet additive solutions (PAS) allow to maintain platelet storage properties in platelet concentrates (PCs). The aim of the present study was to evaluate the in-vitro quality of irradiated and non-irradiated PCs, suspended in PAS, over a storage period of 6 days.

Effect of amphotericin B and fluconazole on platelet membrane glycoproteins

BACKGROUND : Fever, chills, and reduced platelet recovery may result when platelets are transfused simultaneously with amphotericin B. Amphotericin B reportedly increases the pitting of membranes in stored platelets. STUDY DESIGN AND METHODS : The effects of amphotericin B and another antifungal agent, fluconazole, on platelet membrane glycoproteins (GP) were examined by the incubation of split aliquots of fresh and stored platelet concentrates (PCs) with these drugs for 3 days in storage bags. To determine the effect of storage, PCs were stored for 5 days, and aliquots removed on Days 1 through 5 were placed in platelet storage bags with 4 micrograms per mL of amphotericin B for 2 to 6 hours. Membrane glycoprotein expression was assessed by flow cytometry with fluorescein isothiocyanate-labeled monoclonal antibodies (MoAbs) directed against the following antigens: GPIb (CD42b), CD63 (an activation protein), P-selectin (CD62), and GPIIb/IIIa (CD41a). RESULTS : Amphotericin B produced a concentration-dependent decrease in the surface binding of CD42b MoAb with no consistent changes in the binding of CD41a, CD63, or CD62 MoAbs after a 3-day exposure. Stored but not fresh PCs showed decreased binding of MoAb CD42b after a 6-hour exposure to amphotericin B (4 micrograms/mL). Fluconazole produced no changes. When the binding of MoAb CD42b to permeabilized platelets was used to measure total platelet content, amphotericin B (4 micrograms/mL) decreased MoAb CD42b binding to a similar degree in fresh and stored platelets. Inhibition of aggregation to ADP and collagen and ADP and epinephrine was seen in stored but not fresh PCs. CONCLUSION : Therapeutic levels of amphotericin B resulted in partial loss of total platelet GPIb in fresh and stored PCs, but decreased surface expression of platelet membrane GPIb only in stored platelets. This difference between fresh and stored platelets may be related to the limited reservoir of GPIb available for redistribution to the membrane in the previously stored PCs and may account for the decreased recovery of transfused platelets observed in some patients receiving amphotericin B.     

N-acetylcysteine reduce the stress induced by cold storage of platelets: A potential way to extend shelf life of platelets

The room temperature storage used for platelets worldwide leads to platelet storage lesion (PSL) and risk of bacterial growth, limiting platelet shelf life and safety in transfusion. Thus, there is a need for an alternative storage method that can serve as effective temperature storage for platelet concentrates (PCs). In the previous investigation, we have shown that N-acetylcysteine (NAC) is a potential candidate for an additive solution to retain platelet characteristics during cold storage for up to 5 days. However, the study partially describes the efficacy and has drawbacks to address. Here, we used the apheresis platelet product with 50 mM NAC and stored up to 10 days under refrigerated condition (4 ± 1 °C). Stored platelet concentrates were analyzed for critical parameters such as platelet activation, annexin V binding, sialic acid, reactive oxygen species (ROS), neuraminidase activity, and in vivo efficacy using Prkdc^scid mice. Investigation observations revealed that PCs with NAC showed reduced platelet activation, annexin V binding, ROS production, and sialic acid levels. in vivo recovery of PCs showed similar recovery rates stored PCs irrespective of treatment or storage condition. However, on the tenth day after 24 h, recovery in room temperature stored concentrates was about 32 %, whereas in NAC treated refrigerated concentrates, it stands at 47 %. These observations indicate that NAC addition protects refrigerated concentrates during long-term storage retaining the platelet integrity. The study also suggests that extending PC storage beyond 10 days is practically accomplishable with efficacy similar to room temperature (RT) stored PCs.     

In vitro cell quality of buffy coat platelets in additive solution treated with pathogen reduction technology

BACKGROUND: Pathogen reduction technologies (PRTs) may induce storage lesion in platelet (PLT) concentrates. To investigate this, buffy coat PLTs (BCPs) in PLT additive solution (AS; SSP+) with or without Mirasol PRT (CaridianBCT Biotechnologies) were assessed by quality control tests and four‐color flow cytometry. STUDY DESIGN AND METHODS: In vitro comparison of PRT and control pooled‐and‐split BCPs after 2, 3, 6, 7, and 8 days of storage was made. PLT concentration, count per unit, swirl, metabolism, activation (CD62P, PAC1, CD42b/GPIb, CD63, CD40L/CD154, CD40, annexin V), and microparticle, sCD40L, and sCD62P release were evaluated. RESULTS: PRT induced a minor initial PLT loss (Day 2 [mean ± SD], 302 × 10⁹ ± 44 × 10⁹ PLTs/unit vs. 325 × 10⁹ ± 46 × 10⁹ PLTs/unit; p < 0.001) but the decline was comparable to control BCP. Swirling was comparable and declined with similar rates in PRT‐treated and control BCPs during storage. PRT enhanced PLT metabolism and activation, evidenced by lower pH₂₂; increased glucose consumption and lactate production rates (p < 0.01); early increases in CD62P‐, PAC1‐, CD63‐, CD40L‐, CD40‐, and annexin V–positive PLTs; reduced GPIb expression; and enhanced release of PLT‐derived MPs and sCD40L (all p < 0.05). CD62P and PAC1 expression changed with different kinetics during storage and varying GPIb expression was displayed within the CD62P/PAC1‐positive PLT subsets. CONCLUSION: PRT treatment of BCP in AS induced a minor initial PLT loss and enhanced metabolism and PLT activation. The clinical relevance for PLT function in vivo of these findings will be investigated in a clinical trial.