Increase in Glycocalicin Levels in Platelet Concentrates Stored in Plasma or Synthetic Medium for 8 Days: Comparison with Other Platelet Activation Markers

Abstract

Background and Objectives: Glycocalicin (GC) is a proteolytic fragment of GpIb and can conveniently be measured in supernatants of platelet concentrates (PCs) by means of a sandwich ELISA. Because of the convenience of the assay and easy sample storage, we tested its suitability as a sensitive platelet activation parameter during PC storage. Material and Methods: Filtered PCs in plasma or additive solution were made from 5 pooled buffy coats and were subsequently stored during 8 days at 22±2°C. Correlation coefficients (r) were calculated after comparison of GC levels with platelet parameters. Results: A significant increase in GC concentration was found on all subsequent sampling days. PC stored in plasma showed GC levels that correlated well with the soluble P–selectin levels (r = 0.7506), P–selectin (CD62P) expression on platelet membranes (r = 0.8843), morphology scores according to Kunicki (r = –0.7102), lactate concentrations (r = 0.9216), glucose concentrations (r = –0.8913) and β–thromboglobulin (β–TG) concentrations (r = 0.8913). In PCs stored in additive solution, the correlation coefficients with these markers were 0.9209 with soluble P–selectin, 0.7161 with CD62P expression, –0.7474 with morphology score, –0.8908 with glucose concentrations, 0.8923 with lactate concentrations and 0.8908 with β–TG concentrations. Conclusions: The GC concentration correlates well with sensitive platelet (activation) parameters, rendering it a sensitive and convenient parameter for platelet activation.

The mitochondrial membrane potential in human platelets: a sensitive parameter for platelet quality

“…Platelet activation as indicated by up‐regulation of CD62P occurred gradually during storage (Fig. 5B), in agreement with earlier observations 30 . The decrease in JC‐1 signal after prolonged storage was not caused by the (minor) decrease in PLT count, since the same amount of PLTs was used for all samples and variation of the PLT count up to 25 percent did not the affect the values of FL2‐to‐FL1 ratio obtained (data not shown).…”

Role of platelet surface glycoprotein Ibα and P‐selectin in the clearance of transfused platelet concentrates

“…Relatively high recoveries and ST were seen for PLTs with low levels of CD62 exposure and intact GPIbα on their surface, as reflected by the maximal anti‐GPIbα binding. However, when CD62 is highly exposed during prolonged or RF storage, and GPIbα is cleaved, 28‐31 or has a rearranged surface configuration 11,12 resulting in decreased anti‐GPIbα binding, PC recoveries and ST are reduced (Fig. 6).…”

“…2A) and decrease of anti‐GPIbα binding (Fig. 2B) due to proteolytic cleavage 28‐31 and/or rearrangements of GPIbα on the PLT surface 11,12 . CD62 expression correlates with the fast PLT clearance (Fig.…”

Platelet function under high‐shear conditions from platelet concentrates

“…It has been shown in rabbits transfused with human PLTs that high P‐selectin triggers particularly early fast PLT sequestration (within 1 hr), whereas GPIbα governs their later ongoing clearance (8‐12 hr after transfusion) 29 . Proteolytic cleavage of GPIbα from PLTs occurs already within 3 days of storage 30 . Because intact GPIbα is required for adhesion to the polystyrene surface, its cleavage explains a significantly reduced adherence on Day 3 compared to Day 1.…”