Modulation of platelet activation in chronic kidney disease patients on erythropoiesis-stimulating agents

Regular plateletpheresis increased basal concentrations of soluble P-selectin in healthy donors: Possible involvement of endothelial cell activation?

BACKGROUND

We explored the effects of repeated plateletpheresis on the platelet P-selectin expression and soluble P-selectin (sP-selectin) concentrations in platelet donors.

METHODS

Totally 289 platelet donors and 97 first-time whole blood (WB) donors were enrolled from the blood donor registry at the Fujian provincial blood center, China. The accumulative numbers of plateletpheresis in the last 2 y for participants were recorded, and the basal concentrations of platelet count, sP-selectin and total platelet P-selectin (pP-selectin) were determined.

RESULTS

Platelet donors had significantly higher basal concentrations of sP-selectin compared to WB donors (24.12±7.33ng/mL vs. 20.74±5.44ng/mL, P<0.0001), with no difference in platelet count and pP-selectin concentrations. Increased numbers of platelet donation were correlated with a steady increase of sP-selectin (r=0.18, P=0.002). Multivariate regression analysis identified that the frequency of plateletpheresis is an independent factor for the rise of the sP-selectin concentration (t=2.64, P=0.009) while no association was found for pP-selectin and platelet count.

CONCLUSIONS

Repeated plateletpheresis could result in an increased basal concentration of sP-selectin in blood donors whereas not an alteration in the concentrations of total platelet P-selectin. It remains to be determined whether this might be a consequence of endothelial activation or platelet activation or some other phenomenon.

Extracellular Vesicles in Renal Diseases: More than Novel Biomarkers?

Extracellular vesicles from the urine and circulation have gained significant interest as potential diagnostic biomarkers in renal diseases. Urinary extracellular vesicles contain proteins from all sections of the nephron, whereas most studied circulating extracellular vesicles are derived from platelets, immune cells, and the endothelium. In addition to their diagnostic role as markers of kidney and vascular damage, extracellular vesicles may have functional significance in renal health and disease by facilitating communication between cells and protecting against kidney injury and bacterial infection in the urinary tract. However, the current understanding of extracellular vesicles has derived mostly from studies with very small numbers of patients or in vitro data. Moreover, accurate assessment of these vesicles remains a challenge, in part because of a lack of consensus in the methodologies to measure extracellular vesicles and the inability of most techniques to capture the entire size range of these vesicles. However, newer techniques and standardized protocols to improve the detection of extracellular vesicles are in development. A clearer understanding of the composition and biology of extracellular vesicles will provide insights into their pathophysiologic, diagnostic, and therapeutic roles.