Characterization of cerebral small vessel disease by neutrophil and platelet activation markers using artificial intelligence.

Cerebral small vessel disease (cSVD) accounts for 25% of ischemic strokes and is a major cause of cognitive decline. Inflammatory processes, involving immune cells and platelets might drive development and progression of cSVD. The aim of the study was to identify potential novel biomarkers for cSVD, gaining new insights into its pathophysiology. We measured inflammation and platelet and neutrophil activation markers in patients with cSVD and age-matched controls. It was hypothesized that cSVD is accompanied by altered levels of these markers. The levels of interleukin 1ß, CX3CL1, CXCL4, CXCL7, myeloperoxidase (MPO), MPO-DNA complex and S100A8/A9 were measured by ELISA in plasma samples of patients with cSVD presenting with mild vascular cognitive impairment (mVCI, n = 36) or lacunar stroke (Laci, n = 44), and controls (n = 38). To determine the relevance of these ELISA markers compared with patient- and MRI-based characteristics, all characteristics were entered into three machine learning models. Among the ELISA markers measured, MPO levels were significantly elevated in patients with cSVD (48.3 (27.8-80.1, interquartile range) ng/mL) compared with controls (32.2 (19.6-47.4) ng/mL, P = 0.023), particularly in the Laci group (56.8 (33.3-84.7) ng/mL, P = 0.004). Regularized logistic regression and random forest algorithms returned MPO levels as an important feature in the detection and prediction of cSVD. Of note, logistic regression and random forest analysis also highlighted levels of CXCL4, CXCL7, MPO-DNA and S100A8/A9 as features associated with cSVD. Taken together, the neutrophil activation marker MPO is elevated in patients with Laci and machine learning indicates platelet and neutrophil markers as interesting molecules for future investigation. SHORTENED ABSTRACT: Cerebral small vessel disease (cSVD) is a major cause of cognitive decline and stroke. We aimed to identify potential novel biomarkers for cSVD and to obtain new insights into its pathophysiology. Levels of markers reflecting neutrophil activation, neutrophil extracellular trap (NET) formation, platelet activation and vascular inflammation were measured in plasma samples of patients with cSVD, and controls. Only myeloperoxidase (MPO) levels were significantly altered. Regularized logistic regression and random forest algorithms returned MPO levels as an important feature in the detection and prediction of cSVD and highlighted platelet- and NET markers as cSVD associated.

The effect of Bruton's tyrosine kinase inhibitor ibrutinib on atherothrombus formation under stenotic flow conditions.

BACKGROUND: Bruton's kinase (Btk) is critical for collagen-triggered platelet signal transduction. The Btk inhibitor ibrutinib has been shown to selectively block platelet adhesion to atherosclerotic plaque material under laminar arterial flow. However, this has not been studied under a shear gradient, which is characteristic for atherothrombosis. OBJECTIVE: To determine the effect of ibrutinib treatment on in vitro thrombus formation on collagen and atherosclerotic plaque material in the absence or presence of a shear gradient. METHODS: Blood was obtained from patients with chronic lymphocytic leukemia, mantle-cell lymphoma and Waldenström macroglobulinemia with and without ibrutinib treatment and perfused through a microfluidic channel with(out) 60% stenosis over Horm type I collagen or human atherosclerotic plaque homogenate. RESULTS: At a constant shear rate of 1500 s-1, platelet deposition was significantly decreased in blood from haematological malignancy patients treated with ibrutinib as compared to untreated patients, on atherosclerotic plaque material but not on collagen. However, thrombus size, stability, and height, were reduced on both plaque material and collagen. An increase in shear rate up to 3900 s-1, as induced by 60% stenosis, resulted in decreased platelet deposition and thrombus parameters on plaque material but not on collagen when compared to a laminar shear of 1500 s-1. Ibrutinib treatment decreased platelet deposition and thrombus parameters even further around the stenosis. CONCLUSION: Treatment of patients with haematological disorders with the Btk inhibitor ibrutinib reduces in vitro platelet deposition, thrombus size and contraction on human atherosclerotic plaque around a stenosis when compared to patients not receiving ibrutinib.

Characterization of Atherosclerotic Plaque Coating for Thrombosis Microfluidics Assays.

INTRODUCTION: Studying arterial thrombus formation by in vitro flow assays is a widely used approach. Incorporating human atherosclerotic plaque material as a thrombogenic surface in these assays represents a method to model the pathophysiological environment of thrombus formation upon plaque disruption. Up until now, achieving a homogeneous coating of plaque material and subsequent reproducible platelet adhesion has been challenging. Here, we characterized a novel method for coating of plaque material on glass coverslips for use in thrombosis microfluidic assays. METHODS: A homogenate of human atherosclerotic plaques was coated on glass coverslips by conventional manual droplet coating or by spin coating. Prior to coating, a subset of coverslips was plasma treated. Water contact angle measurements were performed as an indicator for the hydrophilicity of the coverslips. Homogeneity of plaque coatings was determined using profilometric analysis and scanning electron microscopy. Thrombogenicity of the plaque material was assessed in real time by microscopic imaging while perfusing whole blood at a shear rate of 1500 s-1 over the plaque material. RESULTS: Plasma treatment of glass coverslips, prior to spin coating with plaque material, increased the hydrophilicity of the coverslip compared to no plasma treatment. The most homogeneous plaque coating and highest platelet adhesion was obtained upon plasma treatment followed by spin coating of the plaque material. Manual plaque coating on non-plasma treated coverslips yielded lowest coating homogeneity and platelet adhesion and activation. CONCLUSION: Spin coating of atherosclerotic plaque material on plasma treated coverslips leads to a more homogenous coating and improved platelet adhesion to the plaque when compared to conventional droplet coating on non-plasma treated coverslips. These properties are beneficial in ensuring the quality and reproducibility of flow experiments. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12195-021-00713-9.

Acquired platelet antagonism: off-target antiplatelet effects of malignancy treatment with tyrosine kinase inhibitors.

Platelets can contribute to tumor progression and metastasis. Cancer patients are at increased risk of thrombosis, and advanced stages of cancer are associated with thrombocytosis or increased platelet reactivity. Tyrosine kinase inhibitors (TKIs) are widely used as a targeted strategy for cancer treatment, with the aim of prolonging progression-free survival of the patients. Because of their broad kinase target spectrum, most TKIs inevitably have off-target effects. Platelets rely on tyrosine kinase activity for their activation. Frequently observed side effects are lowering of platelet count and inhibition of platelet functions, whether or not accompanied by an increased bleeding risk. In this review, we aim to give insights into: (i) 38 TKIs that are currently used for the treatment of different types of cancer, either on the market or in clinical trials; (ii) how distinct TKIs can inhibit activation mechanisms in platelets; and (iii) the clinical consequences of the antiplatelet effects of TKI treatment. For several TKIs, the knowledge on affinity for their targets does not align with the published effects on platelets and reported bleeding events. This review should raise awareness of the potential antiplatelet effects of several TKIs, which will be enhanced in the presence of antithrombotic drugs.