Novel system for storage of buffy-coat-derived platelet concentrates in a glucose-based platelet additive solution: parameters and metabolism during storage and comparison to plasma.

BACKGROUND: In Europe, buffy-coat processing allows for the use of platelet additive solutions (PAS). These solutions, however, have long been questioned for their lack of glucose, a potentially essential nutrient for platelet storage. Using a novel, practical, two-part system for incorporation of glucose into an additive solution (PAS-G), this study compares platelet storage in plasma to storage in PAS-G. STUDY DESIGN AND METHODS: A paired study design of platelet concentrates (PC) were prepared from leucoreduced pools of eight buffy coats (BCP) split into two equal pools, with suspension in autologous plasma, or PAS-G. On days 2, 5, 7 and 9 of storage, samples were tested using standard in vitro platelet parameters. Data were analysed by paired Student's t-tests. RESULTS: During storage, PCs in PAS-G maintain a quality profile that is strikingly similar to PCs stored in plasma in terms of platelet activation (CD62) morphology score, swirl, glucose metabolism and pH. However, PCs in PAS-G perform lower (P < 0.05) in the %ESC and %HSR assays. CONCLUSION: PAS-G's novel presentation allows incorporation of glucose into the additive solution so that it is roughly equivalent to plasma for the maintenance of buffy-coat PCs.

Conjugation to hyperbranched polyglycerols improves RGD-mediated inhibition of platelet function in vitro.

RGD (arginine-glycine-aspartic acid) is a known peptide sequence that binds platelet integrin GPIIbIIIa and disrupts platelet-fibrinogen binding and platelet cross-linking during thrombosis. RGD peptides are unsuitable for clinical applications due to their high 50% inhibitory concentration (IC50) and low in vivo residence times. We addressed these issues by conjugating RGD peptides to biocompatible macromolecular carriers: hyperbranched polyglycerols (HPG) via divinyl sulfone. The GPIIbIIIa binding activity of RGD was maintained after conjugation and the effectiveness of the HPG-RGD conjugate was dependent upon molecular weight and the number of RGD peptides attached to each HPG molecule. These polyvalent inhibitors of platelet aggregation decreased the IC50 of RGD in an inverse linear manner based on the number of RGD peptides per HPG. Since HPG-RGD conjugates do not cause platelet activation by degranulation and certain substitution ratios do not increase fibrinogen binding to resting platelets, HPG-RGD may serve as a model for a novel class of antithrombotics.

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

BACKGROUND AND OBJECTIVES: We developed a viscous platelet additive solution (PAS) based on MacoPharma's SSP+ but containing hydroxyethyl starch to address the poor osmotic balance and low yield associated with conventional PAS for the storage of buffy-coat platelet concentrates (PC). MATERIALS AND METHODS: Pools of four buffy-coats were made into leucoreduced PCs (n = 5) suspended either in plasma or viscous PAS. After determination of platelet recoveries, the PCs were stored under standard conditions. On days 1, 2, 3, 5, 7 and 9, PCs were tested for mean platelet volume, platelet concentration, soluble protein concentration, CD62 expression, platelet morphology, partial pressure of oxygen and partial pressure of carbon dioxide, glucose and lactate concentration, pH, extent of shape change, and hypotonic shock response (HSR). RESULTS: Platelets were prepared with greater ease using the viscous PAS and had improved platelet yield. PCs stored in either plasma or viscous PAS displayed similar storage characteristics to day 9. On days 7 and 9 of storage, platelets stored in viscous PAS displayed significantly lower (P < 0.05) CD62 expression and higher HSR scores than those stored in plasma. CONCLUSION: Alteration of the viscosity of PAS improves platelet recovery during processing and may prolong platelet quality at the later stages of storage.

Prestorage leukoreduction and low-temperature filtration reduce hemolysis of stored red cell concentrates.

BACKGROUND: Universal prestorage leukoreduction in Canada created the perception that stored red cells (RBCs) are more hemolyzed than their unfiltered predecessors. A pool-split design tested the effects of leukoreduction on hemolysis of stored RBCs. STUDY DESIGN AND METHODS: Two ABO-matched units were pooled, divided, and then processed into leukoreduced (LR) and nonleukoreduced (NLR) units with the Pall LT-WB or RC-PL systems and sampled during standard processing and storage for testing of sterility, counts, hemolysis, and osmotic fragility. RESULTS: Room temperature (RT) filtration of 10 pairs of LT-WB-LR and -NLR units showed significantly different percentage of hemolysis (0.39%) and osmotic fragility (0.643%) at 42 days. Cold-stored and -filtered units (2 days at 4 degrees C before processing) were less hemolyzed, but showed a similar proportional decrease of hemolysis in LR units (0.13% vs. 0.25% at 42 days). RBCs from RC-PL systems showed the lowest hemolysis although there was a filtration effect (0.05% vs. 0.12%, 42 days). Osmotic fragility paralleled hemolysis. Segment samples gave inaccurate results. Two-day prefiltration cold storage reduced hemolysis from 0.36 to 0.07 percent (42 days, p < 0.001). RT-LR hemolysis became significantly higher by Day 10 and 4 degrees C LR by Day 12. NLR units showed hemolysis by Day 7. LR units filtered cold were less hemolyzed (p < 0.05) than RT-LR but osmotic fragility was unchanged. CONCLUSIONS: LR-RBCs prepared by any of three methods (LT-WB, RT or cold; RC-PL), filtered at 4 degrees C, were less hemolyzed during storage than nonfiltered concentrates: 4 degrees C leukoreduction is beneficial for RBCs and does not cause hemolysis or enhance fragility.