Comparison of a novel viscous platelet additive solution and plasma: preparation and in vitro storage parameters of buffy-coat-derived platelet concentrates

L-carnitine contributes to enhancement of viability and quality of platelet concentrates through changing the apoptotic and anti-apoptotic associated microRNAs

BACKGROUND

Micro RNAs are known as the main regulator of messenger RNA translation in platelets and have a vital role in process of apoptosis during platelet storage. Our pervious study revealed that the expression of miR-145 and miR-326 changed significantly in platelets under maintenance conditions. This study aimed to evaluate the effect of L-carnitine (LC) as an additive to augment platelet quality by changing the microRNA expression.

METHODS

We used ten platelet concentrate (PC) bags and divided each into two equal parts, LC- treated, and LC free PC. The expression of miR-145 and miR-326 were determined using real-time PCR. Moreover, we measured platelet count, platelet aggregation, platelet viability, and lactate dehydrogenase activity in all samples.

RESULTS

The miR-326 expression significantly increased during platelet storage with mean fold changes of 3.2 for the control and 2.5 for LC- treated PC. The mean fold changes in miR-145 expression was less in the control PC (0.52) compared to the LC- treated PC (0.79). Increased levels of platelet count, platelet aggregation, and platelet viability were found in the LC-treated compared to the untreated PC.

CONCLUSION

LC has a protective effect on platelet apoptosis, reduces the expression of apoptotic microRNA, and prevents the reduction of anti-apoptotic microRNA.

Evaluation of platelet function during extended storage in additive solution, prepared in a new container that allows manual buffy-coat platelet pooling and leucoreduction in the same system

BACKGROUND

A novel and practical storage container designed for manual buffy-coat pooling and leucodepletion was evaluated to assess its filtration performance and to analyse the quality of stored leucoreduced buffy-coat-derived platelet pools.

MATERIALS AND METHODS

To analyse the grifols leucored transfer PL system, blood was collected from random donors into standard triple bag systems, and fractionated using standard procedures to obtain buffy-coats. Ten leucodepleted platelet pools were prepared each from five units of buffy-coats in additive solution. Concentrates were stored for 10 days at 22 °C on an end-over-end agitator. On days 0, 5, 7, and 10 of storage, samples were tested using standard in vitro platelet parameters.

RESULTS

The use of this novel system for volume reduction and leucodepletion of buffy-coats resuspended in additive solution led to platelet pools that met the European requirements. pH was maintained well, declining from an initial value of 7.11±0.04 to 6.88±0.08 after 10 days. Parameters of cell lysis, response to a hypotonic stimulus and aggregation induced by agonists (arachidonic acid, ristocetin, collagen or thrombin receptor activating peptide) were also well-preserved. During storage, the quality profile of the platelet pools remained very similar to that previously reported in platelet concentrates in terms of metabolism, platelet activation (CD62, CD63, sCD62), expression of glycoproteins Ib and IIb/IIIa, capacity of glycoprotein IIb/IIIa to become activated upon ADP stimulation, and release of biological response modifiers (sCD40L and RANTES).

DISCUSSION

This new system allows the preparation of leucodepleted buffy-coat platelet pools in additive solution with good preservation of platelet function. The logistics of the procedure are relatively simple and it results in good-quality components, which may reduce costs and ease the process of buffy-coat pooling and leucocyte reduction in transfusion services.

Development of a quality monitoring program for platelet components: a report of the first four years' experience at Canadian Blood Services

BACKGROUND

A quality monitoring program (QMP) for platelet concentrates (PCs) was implemented at Canadian Blood Services (CBS) to improve standards and to better understand platelet (PLT) products by supplementing routine quality control (QC).

STUDY DESIGN AND METHODS

Annual surveys of PCs from CBS production sites were conducted, with four completed to date (QMP Cycles 1-4) spanning two different PC production methods: PLT-rich plasma (PRP) and buffy coat (BC). Randomly selected PCs were sent to a central laboratory and tested 1 day after expiry. An expanded panel of tests including CD62P expression by flow cytometry, mean PLT volume, PLT count and morphology, extent of shape change, and PLT metabolic parameters, were applied.

RESULTS

QMP data on the implementation of the BC production method across CBS indicated that BC PCs have less variable in vitro quality measures than PRP PCs. For the QC parameters pH and PLT count per unit, the range of mean values from each site for QMP 3 and 4 fell well within the range defined by regulatory standards, a first step in defining quality benchmarks for PCs. Of the extended panel of quality parameters, CD62P expression was the most sensitive indicator of change and identified an issue with the implementation of the BC PC production method at one site, which was subsequently remedied.

CONCLUSION

A QMP was found to be useful to monitor production processes across sites and highlights best practice approaches while deepening understanding of the quality of PLT products at CBS.

In vitro quality of single-donor platelets treated with riboflavin and ultraviolet light and stored in platelet storage medium for up to 8 days

BACKGROUND

The Mirasol pathogen reduction technology system is known to increase the activation and metabolic rate of platelets (PLTs). Storage of Mirasol PLTs in PLT storage medium (PSM) has the potential to slow this accelerated PLT storage lesion. We investigated the quality of Mirasol-treated PLTs stored in either 50% SSP+ or 50% Composol for 8 days.

STUDY DESIGN AND METHODS

Single-donor double hyperconcentrates were divided between control and Mirasol-treated arms and after treatment were suspended in approximately 50% (vol/vol) SSP+ (n = 8) or Composol (n = 7). In vitro markers of PLT activation and/or apoptosis were measured over an 8-day storage period.

RESULTS

Mirasol treatment resulted in increased spontaneous PLT activation and glycolysis and these effects were worsened when PLTs were treated below a certain volume (150 mL). At higher treatment volumes there were no significant differences between treated units stored in either Composol or SSP+. When low-volume units were stored in Composol the median pH fell below 6.4 on Day 5 and bicarbonate was undetectable, whereas in SSP+ the median pH value was greater than 6.9 and bicarbonate remained at detectable levels, despite other markers of in vitro function being similar to those of Composol.

CONCLUSION

Mirasol treatment of PLTs followed by storage in PSM results in increased PLT activation and metabolism to a level similar to that reported for PLTs treated and stored in plasma. Units treated at a low volume (<150 mL) showed poor in vitro quality.

Effect of platelet additive solution on bacterial dynamics and their influence on platelet quality in stored platelet concentrates

BACKGROUND

Platelet additive solutions (PASs) are an alternative to plasma for the storage of platelet concentrates (PCs). However, little is known about the effect of PAS on the growth dynamics of contaminant bacteria. Conversely, there have been no studies on the influence of bacteria on platelet (PLT) quality indicators when suspended in PAS.

STUDY DESIGN AND METHODS

Eight buffy coats were pooled, split, and processed into PCs suspended in either plasma or PAS (SSP+, MacoPharma). PCs were inoculated with 10 and 100 colony-forming units (CFUs)/bag of either Serratia liquefaciens or Staphylococcus epidermidis. Bacterial growth was measured over 5 days by colony counts and bacterial biofilm formation was assayed by scanning electron microscopy and crystal violet staining. Concurrently, PLT markers were measured by an assay panel and flow cytometry.

RESULTS

S. liquefaciens exhibited an apparent slower doubling time in plasma-suspended PCs (plasma-PCs). Biofilm formation by S. liquefaciens and S. epidermidis was significantly greater in PCs stored in plasma than in PAS. Although S. liquefaciens altered several PLT quality markers by Days 3 to 4 postinoculation in both PAS- and plasma-PCs, S. epidermidis contamination did not produce measurable PLT changes.

CONCLUSIONS

S. liquefaciens can be detected more quickly in PAS-suspended PCs (PAS-PCs) than in plasma-PCs by colony counting. Furthermore, reduced biofilm formation by S. liquefaciens and S. epidermidis during storage in PAS-PCs increases bacteria availability for sampling detection. Culture-based detection remains the earliest indicator of bacterial presence in PAS-PCs, while changes of PLT quality can herald S. liquefaciens contamination when in excess of 10(8) CFUs/mL.

Proteomics meets blood banking: identification of protein targets for the improvement of platelet quality

Proteomics has brought new perspectives to the fields of hematology and transfusion medicine in the last decade. The steady improvement of proteomic technology is propelling novel discoveries of molecular mechanisms by studying protein expression, post-translational modifications and protein interactions. This review article focuses on the application of proteomics to the identification of molecular mechanisms leading to the deterioration of blood platelets during storage - a critical aspect in the provision of platelet transfusion products. Several proteomic approaches have been employed to analyse changes in the platelet protein profile during storage and the obtained data now need to be translated into platelet biochemistry in order to connect the results to platelet function. Targeted biochemical applications then allow the identification of points for intervention in signal transduction pathways. Once validated and placed in a transfusion context, these data will provide further understanding of the underlying molecular mechanisms leading to platelet storage lesion. Future aspects of proteomics in blood banking will aim to make use of protein markers identified for platelet storage lesion development to monitor proteome changes when alterations such as the use of additive solutions or pathogen reduction strategies are put in place in order to improve platelet quality for patients.

The platelet storage lesion

The continuous increase in the demand for platelet transfusion has necessitated the need to establish standards for determining the quality of platelets during storage. Bacterial contamination of platelet products and deleterious changes in structure and function referred to as the platelet storage lesion (PSL), have restricted the platelet shelf life to 5 days. The PSL and platelet health variables have been well studied and documented. The precise correlation between in vitro assays and in vivo platelet recovery and survival is yet to be established. This review presents an overview of the current understanding of PSL and the novel approaches being developed to negate the storage lesion.

A signaling pathway contributing to platelet storage lesion development: targeting PI3-kinase-dependent Rap1 activation slows storage-induced platelet deterioration

BACKGROUND

The term platelet storage lesion (PSL) describes the structural and biochemical changes in platelets (PLTs) during storage. These are typified by alterations of morphologic features and PLT metabolism leading to reduced functionality and hence reduced viability for transfusion. While the manifestations of the storage lesion are well characterized, the biochemical pathways involved in the initiation of this process are unknown.

STUDY DESIGN AND METHODS

A complementary proteomic approach has recently been applied to analyze changes in the PLT proteome during storage. By employing stringent proteomic criteria, 12 proteins were identified as significantly and consistently changing in relative concentration over a 7-day storage period. Microscopy, Western blot analysis, flow cytometry, and PLT functionality analyses were used to unravel the involvement of a subset of these 12 proteins, which are connected through integrin signaling in one potential signaling pathway underlying storage lesion development.

RESULTS

Microscopic analysis revealed changes in localization of glycoprotein IIIa, Rap1, and talin during storage. Rap1 activation was observed to correlate with expression of the PLT activation marker CD62P. PLTs incubated for 7 days with the PI3-kinase inhibitor LY294002 showed diminished Rap1 activation as well as a moderate reduction in integrin alphaIIbbeta3 activation and release of alpha-granules. Furthermore, this inhibitor seemed to improve PLT integrity and quality during storage as several in vitro probes showed a deceleration of PLT activation.

CONCLUSION

These results provide the first evidence for a signaling pathway mediating PSL in which PI3-kinase-dependent Rap1 activation leads to integrin alphaIIbbeta3 activation and PLT degranulation.