The Neurovascular Unit: Focus on the Regulation of Arterial Smooth Muscle Cells

2020 ◽  
Vol 16 (5) ◽  
pp. 502-515 ◽  
Author(s):  
Patrícia Quelhas ◽  
Graça Baltazar ◽  
Elisa Cairrao

The neurovascular unit is a physiological unit present in the brain, which is constituted by elements of the nervous system (neurons and astrocytes) and the vascular system (endothelial and mural cells). This unit is responsible for the homeostasis and regulation of cerebral blood flow. There are two major types of mural cells in the brain, pericytes and smooth muscle cells. At the arterial level, smooth muscle cells are the main components that wrap around the outside of cerebral blood vessels and the major contributors to basal tone maintenance, blood pressure and blood flow distribution. They present several mechanisms by which they regulate both vasodilation and vasoconstriction of cerebral blood vessels and their regulation becomes even more important in situations of injury or pathology. In this review, we discuss the main regulatory mechanisms of brain smooth muscle cells and their contributions to the correct brain homeostasis.

1990 ◽  
Vol 73 (1) ◽  
pp. 82-90 ◽  
Author(s):  
Issei Ushiwata ◽  
Tatsuo Ushiki

✓ The three-dimensional cytoarchitecture of the smooth muscles and pericytes of rat cerebral blood vessels was studied by scanning electron microscopy after removing extracellular connective tissue matrices with the KOH-collagenase digestion method. The tunica media of major intracranial arteries such as the internal carotid, vertebral, basilar, and other cerebral arteries measuring more than 100 µm in outer diameter consisted of spindle-shaped smooth-muscle cells arranged circularly to the long axis of the vessel. Muscle cells at the branching points, however, showed a variety of shapes, sizes, and arrangements. As the vessel size decreased, smooth-muscle cells showed bi- or trifurcations at the cell poles. In the precapillary arterioles, smooth-muscle cells which had helically surrounded the endothelial tubes had bulging cell bodies with various cytoplasmic processes extending from the cell poles. Distinct specializations presumed to be sphincters were not found on the arteries or arterioles. Pericytes of the capillary had become extended along the vessel axis, having fusiform cell bodies with longitudinally oriented long cytoplasmic processes. Cells located periendothelially in the venules and veins were stellate in shape with many cytoplasmic processes which were interwoven to form complicated cellular networks around the endothelial tube.


2021 ◽  
pp. 1-13
Author(s):  
Kaveh Sanaei ◽  
Sydney Plotner ◽  
Anson Oommen Jacob ◽  
Jaime Ramirez-Vick ◽  
Narendra Vyavahare ◽  
...  

BACKGROUND: The main objective of tissue engineering is to fabricate a tissue construct that mimics native tissue both biologically and mechanically. A recurring problem for tissue-engineered blood vessels (TEBV) is deficient elastogenesis from seeded smooth muscle cells. Elastin is an integral mechanical component in blood vessels, allowing elastic deformation and retraction in response to the shear and pulsatile forces of the cardiac system. OBJECTIVE: The goal of this research is to assess the effect of the vitamin A derivative all-trans retinoic acid (RA) and polyphenol pentagalloyl glucose (PGG) on the expression of elastin in human aortic smooth muscle cells (hASMC). METHODS: A polycaprolactone (PCL) and the gelatin polymer composite was electrospun and doped with RA and PGG. The scaffolds were subsequently seeded with hASMCs and incubated for five weeks. The resulting tissue-engineered constructs were evaluated using qPCR and Fastin assay for their elastin expression and deposition. RESULTS: All treatments showed an increased elastin expression compared to the control, with PGG treatments showing a significant increase in gene expression and elastin deposition.


Author(s):  
Rashmi Monteiro ◽  
Shikha Sharma ◽  
Sonal Gupta ◽  
Indu Choudhary

Angiomyolipoma is a benign neoplasm composed of variable admixture of blood vessels, smooth muscle cells and adipose tissue. Cervical angiomyolipoma are extremely rare and to the best of our knowledge only five cases of angiomyolipoma in cervix have been reported in the literature till date. Authors are presenting a case of angiomyolipoma arising from the uterine cervix. 43 years old female presented with mass descending per vagina for 6 months. This case had no association with tuberous sclerosis. Microscopic examination showed an ill-defined polypoidal, non-encapsulated lesion covered by keratinized stratified epithelium. The lesion is made up of three components, predominantly by fascicles of spindle shaped cells, varying sized blood vessels and multiple foci of mature adipocytes with no evidence of atypia or increased mitotic activity. Smooth muscle component showed strong immunoreactivity to SMA and absence of elastic fibres in the blood vessels were confirmed by histochemistry. Non-vascular smooth muscle cells were negative for HMB-45 in contrast to renal and other extra-renal angiomyolipoma in which HMB-45 immunoreactivity in seen in these cells. To conclude, the differential diagnosis of lower abdominal mass and dysfunctional uterine bleeding should include the angiomyolipoma, even though the uterine cervix is an extremely rare location where they occur.


Author(s):  
Roxana Aldea ◽  
Roy O. Weller ◽  
Donna M. Wilcock ◽  
Roxana O. Carare ◽  
Giles Richardson

1975 ◽  
Author(s):  
V. Noordhoek Hegt

Endothelial plasminogen activator activity in different types of human blood vessels obtained from fifty necropsies and thirty-five biopsies was detected and localized by means of plasminogen-rich fibrin slides. Great differences in endothelial activator activity were found along and across (vasa vasorum) the wall of the human vascular system.The same blood vessels were simultaneously investigated by a modified fibrin slide technique using plasminogen-free fibrin slides covered by plasmin to detect and localize inhibition of fibrinolysis in the vascular wall. The great variation in plasmin inhibition in different vessels revealed by this “fibrin slide sandwich technique” appeared to be closely associated with the localization and number of smooth muscle cells present in the walls of the vascular system. Strong plasmin inhibition was generally found at sites which showed no activator activity with the regular fibrin slide technique, while areas with a high endothelial fibrinolytic activity mostly revealed no inhibitory capacity.These results indicate that much of the variation in endothelial fibrinolytic activity on fibrin slides is due to inhibitory effects from the surrounding smooth muscle cells rather than to variability in the plasminogen activator content of the endothelium itself.


Physiology ◽  
1992 ◽  
Vol 7 (4) ◽  
pp. 152-156 ◽  
Author(s):  
SS Segal

Peripheral blood flow control during exercise is coordinated among several vascular locations. The locus of control shifts upstream from distal arterioles into feeding arteries as metabolic demand increases. This shift occurs by cell-to-cell conduction and by flow-dependent endothelial cell-mediated relaxation of smooth muscle cells.


1997 ◽  
Vol 17 (4) ◽  
pp. 665-671 ◽  
Author(s):  
Frank T. L. van der Loop ◽  
Giulio Gabbiani ◽  
Gaby Kohnen ◽  
Frans C. S. Ramaekers ◽  
Guillaume J. J. M. van Eys

2013 ◽  
Vol 305 (8) ◽  
pp. C829-C845 ◽  
Author(s):  
Hanaa K. B. Motawea ◽  
Selvi C. Jeyaraj ◽  
Ali H. Eid ◽  
Srabani Mitra ◽  
Nicholas T. Unger ◽  
...  

The second messenger cyclic AMP (cAMP) plays a vital role in vascular physiology, including vasodilation of large blood vessels. We recently demonstrated cAMP activation of Epac-Rap1A and RhoA-Rho-associated kinase (ROCK)-F-actin signaling in arteriolar-derived smooth muscle cells increases expression and cell surface translocation of functional α2C-adrenoceptors (α2C-ARs) that mediate vasoconstriction in small blood vessels (arterioles). The Ras-related small GTPAse Rap1A increased expression of α2C-ARs and also increased translocation of perinuclear α2C-ARs to intracellular F-actin and to the plasma membrane. This study examined the mechanism of translocation to better understand the role of these newly discovered mediators of blood flow control, potentially activated in peripheral vascular disorders. We utilized a yeast two-hybrid screen with human microvascular smooth muscle cells (microVSM) cDNA library and the α2C-AR COOH terminus to identify a novel interaction with the actin cross-linker filamin-2. Yeast α-galactosidase assays, site-directed mutagenesis, and coimmunoprecipitation experiments in heterologous human embryonic kidney (HEK) 293 cells and in human microVSM demonstrated that α2C-ARs, but not α2A-AR subtype, interacted with filamin. In Rap1-stimulated human microVSM, α2C-ARs colocalized with filamin on intracellular filaments and at the plasma membrane. Small interfering RNA-mediated knockdown of filamin-2 inhibited Rap1-induced redistribution of α2C-ARs to the cell surface and inhibited receptor function. The studies suggest that cAMP-Rap1-Rho-ROCK signaling facilitates receptor translocation and function via phosphorylation of filamin-2 Ser2113. Together, these studies extend our previous findings to show that functional rescue of α2C-ARs is mediated through Rap1-filamin signaling. Perturbation of this signaling pathway may lead to alterations in α2C-AR trafficking and physiological function.


2004 ◽  
Vol 24 (10) ◽  
pp. 1810-1815 ◽  
Author(s):  
Anna-Karin Wihlborg ◽  
Lingwei Wang ◽  
Oscar Östberg Braun ◽  
Atli Eyjolfsson ◽  
Ronny Gustafsson ◽  
...  

2018 ◽  
Author(s):  
Thomas R. Whitesell ◽  
Paul Chrystal ◽  
Jae-Ryeon Ryu ◽  
Nicole Munsie ◽  
Ann Grosse ◽  
...  

AbstractDespite the critical role of vascular mural cells (smooth muscle cells and pericytes) in supporting the endothelium of blood vessels, we know little of their early morphogenesis and differentiation. foxc1b:EGFP expressing cells in zebrafish associate with the vascular endothelium (kdrl) and co-express a smooth muscle marker (acta2), but not a pericyte marker (pdgfrβ). The expression of foxc1b in early peri-endothelial mesenchymal cells allows us to follow the morphogenesis of mesenchyme into acta2 expressing vascular smooth muscle cells. We show that mural cells expressing different markers associate with vessels of different diameters, depending on their embryonic location and developmental timing, suggesting marker expression is predictive of functional differences. We identify gene expression signatures for an enriched vascular smooth muscle cell population (foxc1b + acta2) and all smooth muscle (acta2) using fluorescence-activated cell sorting and RNA-Seq. Finally, we demonstrate that progressive loss of foxc1a/foxc1b results in decreased smooth muscle cell coverage. Together, our data highlight the early cellular dynamics and transcriptome profiles of smooth muscle cells in vivo, using foxc1b as a unique tool to probe vascular smooth muscle cell differentiation.Summary StatementTracing the morphogenesis and transcriptome of early vascular smooth muscle cells using foxc1b


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