Intravital Assessment of Blood Platelet Function. A Review of the Methodological Approaches with Examples of Studies of Selected Aspects of Blood Platelet Function

Monocytohigh-density lipoprotein ratio has a high predictive value for the diagnosis of multiple system atrophy and the differentiation from Parkinson’s disease

Background and purpose

Inflammation is closely related to the pathogenesis of multiple system atrophy (MSA). As markers of inflammation, the monocyte to high-density lipoprotein ratio (MHR), neutrophil to lymphocyte ratio (NLR), and red cell distribution width to platelet ratio (RPR) have been proven to be associated with a large variety of diseases. The aim of this study was to explore the association between inflammatory markers (MHR, NLR, and RPR) and MSA, and the difference between MSA and Parkinson’s disease (PD) was further compared by these inflammatory markers.

Materials and methods

This study was divided into three groups: 47 patients with MSA, 125 patients with PD, and 124 healthy controls. The corresponding laboratory indicators of subjects were collected and analyzed to obtain MHR, NLR, and RPR values.

Results

Compared with healthy controls, the MHR, NLR, and RPR were higher in the MSA group (P < 0.05), and the MHR was higher in the MSA group than in the PD group (P < 0.001). Multivariate logistic regression analysis showed that MHR*10 (corrected OR = 1.312, 95% CI 1.093–1.575) and RPR*100 (corrected OR = 1.262, 95% CI 1.055–1.509) were positively correlated with the risk of MSA. The receiver operating characteristic (ROC) curve indicated that the areas under the curve (AUCs) of the MHR, NLR, and RPR for predicting MSA were 0.651 (95% CI 0.562–0.74; P < 0.05), 0.6 (95% CI 0.501–0.699; P < 0.05), and 0.612 (95% CI 0.516–0.708; P < 0.05), respectively. The AUC of MSA and PD predicted by the MHR was 0.727 (P < 0.001). When the cut-off value was 0.38, the sensitivity and specificity were 60 and 77%, respectively. Spearman correlation analysis showed that the MHR was significantly and positively correlated with the course of MSA cerebellar type (MSA-C) patients.

Conclusion

There may be peripheral inflammation in patients with MSA. Compared with NLR and RPR, MHR has higher predictive value for the diagnosis and differential diagnosis of MSA.

Characterization of Ferric Chloride-Induced Arterial Thrombosis Model of Mice and the Role of Red Blood Cells in Thrombosis Acceleration

PURPOSE

The ferric chloride (FeCl₃)-induced thrombosis model is widely used for thrombosis research. However, it lacks standardization with uncertainty in the exact mechanism of thrombosis. This study aimed to characterize thrombus formation in a mouse model.

MATERIALS AND METHODS

We investigated thrombus formation and stability using various FeCl₃ concentrations (10%, 20%, 30%, 40%, and 50%, w/v) in carotid arteries of the Institute of Cancer Research (ICR) and C57BL/6N mice using the FeCl₃-induced thrombosis model. We also investigated thrombus histopathology using immunohistochemistry and electron microscopy.

RESULTS

Higher FeCl₃ concentrations induced dose-dependent, faster, larger, and more stable thrombus formation in both strains of mice. However, the ICR mice showed better dose-responses in thrombus formation and stability compared to the C57BL/6N mice. Thrombi were fibrin- and platelet-rich without significant changes across FeCl₃ concentrations. However, the content of red blood cells (RBCs) increased with increasing FeCl₃ concentrations (p for trend <0.001) and inversely correlated with time to occlusion (r=-0.65, p<0.001). While platelets and fibrin were evenly distributed over the thrombus, RBCs were predominantly located near the FeCl₃ treatment area. Transmission electron microscopy showed that RBCs attached to and were surrounded by aggregates of degranulated platelets, suggesting their potential role in platelet activation.

CONCLUSION

Faster and larger thrombus formation is induced in a dose-dependent manner by a wide range of FeCl₃ concentrations, but the stable thrombus formation requires higher FeCl₃ concentrations. Mouse strain affects thrombus formation and stability. RBCs and their interaction with platelets play a key role in the acceleration of FeCl₃-induced thrombosis.

In Vivo Platelet Detection Using a Glycoprotein IIb/IIIa-Targeted Near-Infrared Fluorescence Imaging Probe

Platelets play a prominent role in multiple diseases, in particular arterial and venous thrombosis and also in atherosclerosis and cancer. To advance the in vivo study of the biological activity of this cell type from a basic experimental focus to a clinical focus, new translatable platelet-specific molecular imaging agents are required. Herein, we report the development of a near-infrared fluorescence probe based upon tirofiban, a clinically approved small-molecule glycoprotein IIb/IIIa inhibitor (GPIIb/IIIa). Through in vitro experiments with human platelets and in vivo ones in a murine model of deep-vein thrombosis, we demonstrate the avidity of the generated probe for activated platelets, with the added benefit of a short blood half-life, thereby enabling rapid in vivo visualization within the vasculature.

Thrombocytopathies: Not Just Aggregation Defects-The Clinical Relevance of Procoagulant Platelets

Platelets are active key players in haemostasis. Qualitative platelet dysfunctions result in thrombocytopathies variously characterized by defects of their adhesive and procoagulant activation endpoints. In this review, we summarize the traditional platelet defects in adhesion, secretion, and aggregation. In addition, we review the current knowledge about procoagulant platelets, focusing on their role in bleeding or thrombotic pathologies and their pharmaceutical modulation. Procoagulant activity is an important feature of platelet activation, which should be specifically evaluated during the investigation of a suspected thrombocytopathy.