Electron microscopic observation in case of platelet activation in a chronic haemodialysis subject

Haemodiafiltration elicits less platelet activation compared to haemodialysis

Background

Mortality in patients with end-stage renal disorders is often a consequence of cardiovascular complications. Renal replacement therapies may contribute to this morbidity by promoting cellular activation. In renal failure patients peripheral blood samples were investigated for platelet and endothelial cell activation markers to compare the effects of haemodiafiltration (HDF) and haemodialysis (HD).

Methods

Overall 28 patients were included in the study. Platelet P-selectin and leukocyte - platelet heterotypic aggregates were studied by flow cytometry. Soluble P- and E-selectin values were determined by ELISA, while von Willebrand factor (vWF) antigen levels were measured by immunoturbidimetry. Statistical analysis was done by the SPSS v22 software.

Results

Platelet surface P-selectin was below 3.0 % in healthy controls, but it was higher during the dialysis after 4 h, 8 % and 14.3 % in HDF and HD, respectively. Monocyte-platelet heterotypic aggregates were significantly elevated after 4 h in both treatments, up to 69.2 % in HDF and to 82.9 % in HD. Soluble P-selectin levels were also significantly elevated by the end of both treatment procedures (p < 0.001), vWF antigen values, however, showed elevation only during HD treatment.

Conclusions

The attenuated platelet activating effects of HDF compared to HD may contribute to a less unfavourable vascular effect in this treatment modality.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0364-x) contains supplementary material, which is available to authorized users.

The evaluation of platelet indices and markers of inflammation, coagulation and disease progression in treatment-naïve, asymptomatic HIV-infected individuals

INTRODUCTION

Cardiovascular disease and thrombotic events have emerged as major causes of mortality in people living with HIV. Activated platelets play a key role in both inflammation and thrombosis. Haematology analysers measure a variety of platelet indices, which could be surrogate markers of platelet activation. Flow cytometry offers the discrimination of platelet subpopulations and evaluation of the activation status of platelets. This study aimed to measure platelet indices in untreated HIV infection and to evaluate their relationship with markers of immune activation and disease progression.

MATERIALS AND METHODS

One hundred and eighty-five antiretroviral therapy (ART)-naïve HIV-infected and 145 HIV-negative healthy individuals were recruited. Platelet indices measured using the ADVIA 2120 platform consisted of platelet count (PLT ×10(9) /L), mean platelet volume (MPV fL), platelet distribution width (PDW%) and plateletcrit (PCT%). These were correlated with CD4 count, %CD38 on CD8+ (CD38/8) T cells, viral load, fibrinogen, D-dimers and CD31+ platelet CD62P and CD36 expression, determined using flow cytometry.

RESULTS

The HIV group had decreased MPV levels [median 7.7 (7.1-8.3) vs. control group 8.4 (7.8-9.2), P < 0.0001], which correlated with PCT% (r = 0.3038, P = 0.0013), viral load (r = 0.2680, P = 0.0177) and PDW% (r = 0.2479, P = 0.0257). Additionally, the MPV correlated with CD4 count r = -0.2898, P = 0.0075. The HIV group had decreased PDW%, 49.35 (46.40-52.65) vs. control group, 53.90 (50-56.80), P = 0.0170. In addition, the PDW% showed correlations with D-dimers (r = 0.443, P = 0.03) and %CD36 (r = -0.3666, P = 0.0463).

CONCLUSION

Platelet indices may offer a rapid and affordable method for monitoring platelet activation and disease progression in patients with HIV.

Platelets of patients with chronic kidney disease demonstrate deficient platelet reactivity in vitro

Background

In patients with chronic kidney disease studies focusing on platelet function and properties often are non-conclusive whereas only few studies use functional platelet tests. In this study we evaluated a recently developed functional flow cytometry based assay for the analysis of platelet function in chronic kidney disease.

Methods

Platelet reactivity was measured using flow cytometric analysis. Platelets in whole blood were triggered with different concentrations of agonists (TRAP, ADP, CRP). Platelet activation was quantified with staining for P-selectin, measuring the mean fluorescence intensity. Area under the curve and the concentration of half-maximal response were determined.

Results

We studied 23 patients with chronic kidney disease (9 patients with cardiorenal failure and 14 patients with end stage renal disease) and 19 healthy controls. Expression of P-selectin on the platelet surface measured as mean fluorescence intensity was significantly less in chronic kidney disease patients compared to controls after maximal stimulation with TRAP (9.7 (7.9-10.8) vs. 11.4 (9.2-12.2), P = 0.032), ADP (1.6 (1.2-2.1) vs. 2.6 (1.9-3.5), P = 0.002) and CRP (9.2 (8.5-10.8) vs. 11.5 (9.5-12.9), P = 0.004). Also the area under the curve was significantly different. There was no significant difference in half-maximal response between both groups.

Conclusion

In this study we found that patients with chronic kidney disease show reduced platelet reactivity in response of ADP, TRAP and CRP compared to controls. These results contribute to our understanding of the aberrant platelet function observed in patients with chronic kidney disease and emphasize the significance of using functional whole blood platelet activation assays.