Denese C. Marks

The hemostatic activity of cryopreserved platelets is mediated by phosphatidylserine-expressing platelets and platelet microparticles.

Cryopreservation of platelets (PLTs) at −80°C with dimethyl sulfoxide (DMSO) can extend the shelf life from 5 days to 2 years. Cryopreserved PLTs are reported to have a greater in vivo hemostatic effect than liquid‐stored PLTs. As such, the aim of this study was to understand the mechanisms responsible for the hemostatic potential of cryopreserved PLTs and the contribution of the reconstitution solution to this activity.

The effect of pathogen reduction technology (Mirasol) on platelet quality when treated in additive solution with low plasma carryover.

Background and Objectives  Pathogen reduction technologies (PRT) for platelets are now compatible with both plasma and platelet additive solutions (PAS). The aim of this study was to examine the effect of PRT on the platelet storage lesion, in the presence of PAS with low plasma carryover.

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

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

Modulation of P-glycoprotein-mediated anticancer drug accumulation, cytotoxicity, and ATPase activity by flavonoid interactions

Flavonoids are components of plant foods and of many herbal medicines taken in combination with anticancer drugs. We have examined the potential of flavonoids to affect the accumulation and cytotoxicity of 3 cytotoxic drugs [vinblastine (VLB), daunorubicin (DNR), and colchicine (COL)] that are substrates for the ABC transporter, P-glycoprotein in a vinblastine-resistant T-cell leukemia, CEM/VBL100, that overexpresses P-glycoprotein. The effects of the flavonoids on accumulation and cytotoxicity of these drugs were different depending on the P-gp substrate used. Most of the 30 flavonoids tested decreased DNR accumulation in the VBL-resistant, but not sensitive, leukemia cells. By contrast, flavonoids that inhibited DNR accumulation enhanced the accumulation of fluorescently labeled vinblastine. None of these flavonoids affected COL accumulation. The effects of the flavonoids on the cytotoxicities of these drugs paralleled their effects on accumulation; the same flavonoids decreased DNR cytotoxicity but increased VLB cytotoxicity and had no effect on COL. Verapamil reversed the accumulation deficit and cytotoxicity of all three P-gp substrates. These effects correlated with the effects of flavonoids on P-gp-ATPase activity. Flavonoids that decreased DNR accumulation stimulated DNR-activated P-gp ATPase, whereas flavonoids that increased fluorescently labeled VLB accumulation inhibited VBL-stimulated P-gp ATPase activity, thereby accounting for the decrease or increase in cancer drug accumulation in resistant cells. We conclude that flavonoids often ingested by cancer patients may have different effects on anticancer drugs and that these findings should be considered in designing future combination treatments for cancer patients.

Cryopreservation of buffy-coat-derived platelet concentrates in dimethyl sulfoxide and platelet additive solution.

Platelets prepared in plasma can be frozen in 6% dimethyl sulfoxide (Me(2)SO) and stored for extended periods at -80°C. The aim of this study was to reduce the plasma present in the cryopreserved product, by substituting plasma with platelet additive solution (PAS; SSP+), whilst maintaining in vitro platelet quality. Buffy coat-derived pooled leukoreduced platelet concentrates were frozen in a mixture of SSP+, plasma and 6% Me(2)SO. The platelets were concentrated, to avoid post-thaw washing, and frozen at -80°C. The cryopreserved platelet units (n=9) were rapidly thawed at 37°C, reconstituted in 50% SSP+/plasma and stored at 22°C. Platelet recovery and quality were examined 1 and 24h post-thaw and compared to the pre-freeze samples. Upon thawing, platelet recovery ranged from 60% to 80%. However, there were differences between frozen and liquid-stored platelets, including a reduction in aggregation in response to ADP and collagen; increased CD62P expression; decreased viability; increased apoptosis and some loss of mitochondrial membrane integrity. Some recovery of these parameters was detected at 24h post-thaw, indicating an extended shelf-life may be possible. The data suggests that freezing platelets in 6% Me(2)SO and additive solution produces acceptable in vitro platelet quality.

Refrigeration and cryopreservation of platelets differentially affect platelet metabolism and function: a comparison with conventional platelet storage conditions.

Alternatives to room temperature storage of platelets (PLTs) may be beneficial to extend the limited shelf life and support transfusion logistics in rural and military areas. The aim of this study was to assess the morphologic, metabolic, and functional aspects of PLTs stored at room temperature or in refrigerated conditions or cryopreserved.

In vitro assessment of buffy-coat derived platelet components suspended in SSP+ treated with the INTERCEPT Blood system

The INTERCEPT Blood System uses amotosalen‐HCl and UVA light to cross‐link DNA and RNA, thereby inhibiting pathogen replication. Although previous studies have shown that this treatment alters in vitro platelet quality, most studies have assessed apheresis platelets or platelets pooled from 5 or 6 donors. In Australia, platelets are prepared using buffy‐coats from 4 donors, with SSP+ and have lower plasma carryover than recommended by the manufacturer (32–47%). As such, it is currently unknown whether these platelet concentrates are suitable for INTERCEPT treatment.

Cryopreservation alters the membrane and cytoskeletal protein profile of platelet microparticles

Cryopreservation of platelets (PLTs) in dimethyl sulfoxide (DMSO) and storage at −80°C extends the PLT shelf life to at least 2 years, allowing greater accessibility in military and rural environments. While cryopreserved PLTs have been extensively characterized, the microparticles formed as a result of cryopreservation are yet to be fully described.

Pathogen reduction treatment of buffy coat platelet concentrates in additive solution induces proapoptotic signaling

BACKGROUND: Pathogen reduction technology (PRT) can potentially reduce the risk of transfusion‐transmitted infections. However, PRT treatment of platelet (PLT) concentrates also results in reduced PLT quality and increased markers of apoptosis during storage. The aim of this study was to investigate changes to the expression and activation of proteins involved in apoptosis signaling.

Evaluation of the automated collection and extended storage of apheresis platelets in additive solution

BACKGROUND: Collecting apheresis platelets (PLTs) into additive solution has many potential benefits. The new Trima software (Version 6.0, CaridianBCT) allows automated addition of PLT additive solution (PAS) after collection, compared to Trima Version 5.1, which only collects PLTs into plasma. The aim of this study was to compare PLT quality during extended storage, after collection with the different Trima systems.