Coagulation activation, depletion of platelet granules and endothelial integrity in case of uraemia and haemodialysis treatment

Abstract

Background: During haemodialysis (HD) treatment, increase of platelet (PLT) activation and induction of procoagulant activity is demonstrated. Although the role of the endothelium and its direct interaction with coagulation and homeostasis is known, it is not elucidated how PLT activation markers and activation of coagulation coincide with markers of endothelial integrity during HD treatment. In the present study uraemia and HD induced changes, with particular emphasis on PLT granules depletion, activation of coagulation and endothelial integrity were investigated.

Methods: To detect depletion of PLT granules, peripheral blood slide smears were screened by light microscopy for qualitative evaluation of PLT granule containing cytoplasm, as indicated by its granules staining density. Activation of coagulation was investigated by establishement of thrombin-antithrombin (TAT) and fibrinogen concentrations. To evaluate endothelial integrity proendothelin (proET-1) plasma concentrations were established.

Results: Results of our study demonstrate that proET-1 plasma concentrations were obviously increased in the subjects' group with end-stage chronic kidney disease (CKD) and renal failure if compared with a group of apparently healthy subjects. The amount of depleted PLT granules was obviously increased in the subjects' group with end-stage CKD if compared with the group with renal failure. Mean plasma concentrations of TAT and fibrinogen revealed results within the reference range.

Conclusions: It is demonstrated that uraemia is associated with endothelial damage and aberrations in PLT granules morphology in subjects with HD treatment. We hypothesize that increased proET-1 concentrations reflect ongoing stress on endothelial cells amongst others due to uraemia. Biomarkers like proET-1 and aberrations in PLT granules morphology assist in the early detection of procoagulant activity of the endothelium.

Figure 1

Biomarker ProET-1 concentrations. Box plots representing proET-1 concentrations established in subjects with end-stage CKD (n = 20) and renal failure (n = 20). For comparison, results for a group of 20 apparently healthy subjects (REF) are depicted. The box extends form the 25^th to the 75^th percentile. The line inside the box indicates the median value. Whiskers extend to the largest and smallest observed values within 1.5 box lengths. Outlying values corresponding with values between 1.5 and 3 times the box length are designated as (0). The horizontal dashed line indicates the upper level of the reference range for apparently healthy subjects. Statistically significant deviations between groups (p < 0.05) are indicated by ∏.

Figure 2

PLT granules staining density. Box plots representing the percentage of PLTs with <25% (left)) and >75% (right) staining intensity of the granules containing cytoplasm established in subjects with end-stage CKD (n = 20) and renal failure (n = 20). For comparison, results for a group of 20 apparently healthy subjects (REF) are depicted. The box extends form the 25^th to the 75^th percentile. The line inside the box indicates the median value. Whiskers extend to the largest and smallest observed values within 1.5 box lengths. Outlying and extreme values corresponding with values between 1.5 and 3 times the box length or > 3 times the box length, respectively, are designated as (0) and (*). The horizontal dashed lines indicate the upper (left) and lower (left) level of the reference range for apparently healthy subjects. Statistically significant deviations between groups (p < 0.05) are indicated by ∏.

Figure 3

Coagulation biomarkers TAT and fibrinogen. Box plots representing TAT (left) and fibrinogen (right) plasma concentrations established in subjects with end-stage CKD (n = 20) and renal failure (n = 20). For comparison, results for a group of 20 apparently healthy subjects (REF) are depicted. The box extends form the 25^th to the 75^th percentile. The line inside the box indicates the median value. Whiskers extend to the largest and smallest observed values within 1.5 box lengths. Outlying values corresponding with values between 1.5 and 3 times the box length are designated as (0). The horizontal dashed line indicates the upper level of the reference range for apparently healthy subjects. Statistically significant deviations between groups (p < 0.05) are indicated by ∏.

Figure 4

Correlation between PLT granules staining density and biomarker proET-1. Relationship between results concerning PLT granules staining density and proET-1 concentrations in the groups with end-stage kidney disease (●), renal failure (o) and apparently healthy subjects (■) respectively.