Arterial thrombi are primarily composed of platelets. Platelets are bound to injured endothelial cells, sub-endothelial matrices, and other platelets by a range of adhesive proteins. Some of these reactions are governed by shear forces. The role of adhesive proteins in the pathogenesis of arterial thrombosis is not fully understood. The aim of this study was to examine the involvement of von Willebrand factor (vWF), fibrinogen (Fg), and fibronectin (FN) in the formation of microvascular thrombi in vivo using a helium-neon laser-induced thrombosis method. Transmission electron microscopy demonstrated that laser irradiation resulted in platelet-rich thrombosis in arterioles and venules, and revealed that this occurred in the absence of endothelial denudation. The mean wall shear rates in mesenteric arterioles and venules were 641 +/- 40 and 280 +/- 20 s-1, respectively. Shear rates increased approximately fivefold in arterioles and tenfold in venules during the formation of occlusive thrombi. Antibody to vWF inhibited thrombosis in arterioles and venules. Antibodies to Fg and FN inhibited thrombosis in venules but not in arterioles. These results confirm that vWF, Fg and FN were involved in thrombogenesis in vivo and demonstrated that significantly higher shear rates were required for the reactions involving vWF than those involving either Fg or FN.
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Trends Neurosci
January 2025
Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA. Electronic address:
Despite extensive functional mapping studies using rodent functional magnetic resonance imaging (fMRI), interpreting the fMRI signals in relation to their neuronal origins remains challenging due to the hemodynamic nature of the response. Ultra high-resolution rodent fMRI, beyond merely enhancing spatial specificity, has revealed vessel-specific hemodynamic responses, highlighting the distinct contributions of intracortical arterioles and venules to fMRI signals. This 'single-vessel' fMRI approach shifts the paradigm of rodent fMRI, enabling its integration with other neuroimaging modalities to investigate neuro-glio-vascular (NGV) signaling underlying a variety of brain dynamics.
View Article and Find Full Text PDFCardiovasc Res
January 2025
Department of Pharmacology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China.
Aims: Dedicator of Cytokinesis 2 (DOCK2), a member of the DOCK family of Guanine nucleotide exchange factors that specifically act on the Rho GTPases including Rac and Cdc42, plays pivotal roles in the regulation of leukocyte homeostasis. However, its functions in platelets remain unknown.
Methods And Results: Using mice with genetic deficiency of DOCK2 (Dock2-/-), we showed that Dock2-/-mice exhibited a macrothrombocytopenic phenotype characterized as decreased platelet count and enlarged platelet size by transmission electron microscopy.
Int J Mol Sci
December 2024
Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany.
Nitric oxide-sensitive guanylyl cyclase (NO-GC) is a heterodimeric enzyme with an α- and a β-subunit. In its active form as an αβ-heterodimer, NO-GC produces cyclic guanosine-3',5'-monophophate (cGMP) to regulate vasodilation and proliferation of vascular smooth muscle cells (VSMCs). In contrast to VSMCs, only a few studies reported on the expression of the NO-GC αβ-heterodimer in human pericytes.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Dipartimento di Biotecnologie e Scienze della Vita, ASST Sette Laghi, Università degli Studi dell'Insubria, 21100 Varese, Italy.
Hypertension exerts a profound impact on the microcirculation, causing both structural and functional alterations that contribute to systemic and organ-specific vascular damage. The microcirculation, comprising arterioles, capillaries, and venules with diameters smaller than 20 μm, plays a fundamental role in oxygen delivery, nutrient exchange, and maintaining tissue homeostasis. In the context of hypertension, microvascular remodeling and rarefaction result in reduced vessel density and elasticity, increasing vascular resistance and driving end-organ damage.
View Article and Find Full Text PDFJ Med Cases
January 2025
Gastroenterology and Hepatology, St. Joseph's University Medical Center, Paterson, NJ, USA.
Heyde syndrome is a triad of aortic stenosis (AS), gastrointestinal (GI) bleeding from angiodysplasia, and acquired von Willebrand disease (vWD). It is hypothesized that stenotic aortic valves cleave von Willebrand factor (vWF) multimers, predisposing patients to bleeding from GI angiodysplasias. This hypothesis is supported by the observation that aortic valve replacement often leads to the resolution of GI bleeding.
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