Endothelial Shear Stress and Platelet FcγRIIa Expression in Intracranial Atherosclerotic Disease

Predicting Cerebral Small Vessel Disease Burden Based on Thromboelastography in Patients with Acute Ischemic Stroke: A Pilot Study

BACKGROUND This study aimed to investigate the relationship between the coagulation function measured by thromboelastography (TEG) in patients with acute ischemic stroke (AIS) and total burden of cerebral small vessel disease (CSVD), to further establish a nomogram tool based on regular clinical risk factors and TEG, to conveniently predict the risk of high-grade white matter hyperintensities (WMH) and CSVD burden in AIS patients. MATERIAL AND METHODS A cross-sectional study included 143 AIS patients who underwent TEG tests and 3.0T head MRI scans after admission. They were grouped according to total burden CSVD score and WMH Fazekas score. Differences in regular clinical data (RCD), TEG, and conventional coagulation tests (CCT) between groups were compared. Three sets of logistic regression models were established: RCD model, and models combining RCD with TEG and CCT respectively, to evaluate their predictive performance for WMH and SVD in patients with AIS. RESULTS Univariate analysis revealed age, hypertension, stroke history, fibrinogen, and TEG indicators maximum amplitude, Angle, K, and coagulation index were risk factors for increased WMH Fazekas score and CSVD burden in patients with AIS (OR>1, P<0.05). Logistic regression model combining RCD and TEG had a higher AUC value in predicting WMH (Fazekas score ≥2) and SVD (SVD burden score ≥3). CONCLUSIONS TEG parameters of patients with AIS are related to CSVD burden and its imaging features. Based on regular clinical risk factors, TEG can provide additional predictive information on the severity of WMHs and the burden of CSVD in patients with AIS.

Remodeling of the brain angioarchitecture in experimental chronic neurodegeneration

Chronic neurodegenerative diseases are characterized by substantial inflammation with putative impairment of the brain vasculature also commonly observed. To address effects of chronic neurodegeneration on the regional vasculature under experimentally controlled circumstances, the glutamate receptor agonist ibotenic acid was injected into striatum of adult rats, which causes excitotoxicity in the substantia nigra pars reticulata (SNpr) due to imbalance between inhibitory inputs from the striatum and excitatory signals from the subthalamic nucleus. Brains were examined at 28 days (short-term neurodegeneration) and 91 days (long-term neurodegeneration) and analyzed for vascular remodeling taking both 2D and 3D approaches, the latter involving confocal microscopy of optically cleared samples combined with machine learning-based image analysis. Crysectioned and microdissected samples were analyzed for protein and gene expression respectively. The resulting neurodegeneration was accompanied by regional tissue loss and inflammation. The 3D analysis of the degenerating SNpr revealed substantial changes of the vasculature with higher density, increased diameter, and number of tortuous vessels already after 28 days, evidently continuing at 91 days. Interestingly, the vascular remodeling changes occurred without changes in the expression of endothelial tight junction proteins, vascular basement membrane proteins, or markers of angiogenesis. We propose that remodeling of the vasculature in neurodegeneration occurs due to regional tissue atrophy, which leaves the vasculature operating but prone to additional pathologies.

Development and Validation of a Flow-Dependent Endothelialized 3D Model of Intracranial Atherosclerotic Disease

Intracranial atherosclerotic disease (ICAD) is a major cause of stroke globally, with mechanisms presumed to be shared with atherosclerosis in other vascular regions. Due to the scarcity of relevant animal models, testing biological hypotheses specific to ICAD is challenging. We developed a workflow to create patient-specific models of the middle cerebral artery (MCA) from neuroimaging studies, such as CT angiography. These models, which can be endothelialized with human endothelial cells and subjected to flow forces, provide a reproducible ICAD model. Using imaging from the SAMMPRIS clinical trial, we validated this novel model. Computational fluid dynamics flow velocities correlated strongly with particle-derived flow, regardless of stenosis degree. Post-stenotic flow disruption varied with stenosis severity. Single-cell RNA-seq identified flow-dependent endothelial gene expression and specific endothelial subclusters in diseased MCA segments, including upregulated genes linked to atherosclerosis. Confocal microscopy revealed flow-dependent changes in endothelial cell proliferation and morphology in vessel segments related to stenosis. This platform, rooted in the specific anatomy of cerebral circulation, enables detailed modeling of ICAD lesions and pathways. Given the high stroke risk associated with ICAD and the lack of effective treatments, these experimental models are crucial for developing new ICAD-related stroke therapies.

Hemodynamic changes for half cover left subclavian artery ostium during thoracic endovascular aortic repair

Purpose

Some clinicians use endografts to cover half the left subclavian artery (LSA) ostium to cure some cases with insufficient proximal landing zone (PLZ) in thoracic endovascular aortic repair (TEVAR) treatment. We used computational fluid dynamics (CFD) to study the hemodynamic changes in the LSA because they may cause acute thrombosis or arteriosclerosis.

Methods

The digital model of the aortic arch was established and named model A, which only included the supraarch branch of the LSA. By directly covering half of the LSA ostium, which was named as model B. All established models were imported into the Gambit grid division software for grid division and were subsequently imported into the Fluent software for hemodynamic numerical simulation and calculation to analyze the related changes in LSA hemodynamic parameters after stent implantation.

Results

Under the same aortic inlet flow, in model B, the local blood flow velocity of the LSA ostium increased and the whole blood flow velocity at the distal end decreased. The average wall shear stress (WSS) of the LSA was significantly decreased. Meanwhile there was an obvious turbulent flow in the LSA lumen, and the related blood flow state was disordered.

Conclusion

CFD research confirmed that the implantation of an endograft covering half the LSA ostium can cause obvious hemodynamic changes, which is likely to cause a long-term arteriosclerosis or acute thrombosis of the LSA, finally increasing the risk of stroke. Once this operation is performed in some specific clinical cases for simplicity and economy, it seems that we should actively antiplatelet and follow up regularly.

Platelet FcγRIIA: An emerging regulator and biomarker in cardiovascular disease and cancer

Platelets, anucleate blood cells derive from megakaryocytes, are involved in cardiovascular diseases and tumors. FcγRIIA, the only FcγR expressed on human platelets, is known for its role in immune-related diseases. A growing body of evidence reveals that platelet FcγRIIA is a potential target for the prevention and control of cardiovascular disease and cancer, and is an advantageous biomarker. In this review, we describe the structure and physiological function of platelet FcγRIIA, its regulatory role in cardiovascular disease and cancer, and its potential clinical application.