Formation of blood vessels in bone maturation and regeneration

The majority of blood vessels in the superior cervical ganglion possess a continuous endothelium with tight junctions. These same features have been associated with the blood brain barrier of the central nervous system and peripheral nerves. These vessels may perform a barrier function between the capillary circulation and the superior cervical ganglion. The permeability of the blood vessels in the superior cervical ganglion of the rat was tested by intravenous injection of horseradish peroxidase (HRP). Three experimental groups of four animals each were given intravenous HRP (Sigma Type II) in a dosage of.08 to.15 mg/gm body weight in.5 ml of.85% saline. The animals were sacrificed at five, ten or 15 minutes following administration of the tracer. Superior cervical ganglia were quickly removed and fixed by immersion in 2.5% glutaraldehyde in Sorenson's.1M phosphate buffer, pH 7.4. Three control animals received,5ml of saline without HRP. These were sacrificed on the same time schedule. Tissues from experimental and control animals were reacted for peroxidase activity and then processed for routine transmission electron microscopy.

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Permeability of Endometrial Blood Vessels to Exogenous Horse Radish Peroxidase in Mice. Electron Microscope Study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073258 ◽

1973 ◽

Vol 31 ◽

pp. 562-563

Author(s):

M.C. Castillo-Jessen ◽

A. González-Angulo

Keyword(s):

Electron Microscopy ◽

Blood Vessels ◽

Electron Microscope Study ◽

Ultrastructural Level ◽

Low Molecular Weight ◽

Horse Radish Peroxidase ◽

Intravascular Injection ◽

Normal Morphology ◽

Functional Implications ◽

Low Molecular Weight Proteins

Information regarding the normal morphology of uterine blood vessels at ultrastructural level in mammals is scarce Electron microscopy studies dealing with endometrial vasculature despite the functional implications due to hormone priming are not available. Light microscopy observations with combined injection of dyes and microradiography along with histochemical studies does not enable us to know the detailed fine structure of the possible various types of blood vessels in this tissue. The present work has been designed to characterize the blood vessels of endometrium of mice as well as the behavior of the endothelium to injection of low molecular weight proteins during the normal estrous cycle in this animal. One hundred and forty female albino mice were sacrificed after intravascular injection of horse radish peroxidase (HRP) at 30 seconds, 5, 15, 30 and 60 minutes.

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Some quantitative applications of vascular corrosion casting

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100124094 ◽

1992 ◽

Vol 50 (1) ◽

pp. 738-739

Author(s):

Fred E. Hossler

Keyword(s):

Blood Vessels ◽

Nuclear Orientation ◽

Three Dimensional ◽

Surrounding Tissue ◽

Confocal Laser ◽

Corrosion Casting ◽

Venous Valve ◽

Casting Technique ◽

Low Viscosity ◽

Quantitative Measurements

Preparation of replicas of the complex arrangement of blood vessels in various organs and tissues has been accomplished by infusing low viscosity resins into the vasculature. Subsequent removal of the surrounding tissue by maceration leaves a model of the intricate three-dimensional anatomy of the blood vessels of the tissue not obtainable by any other procedure. When applied with care, the vascular corrosion casting technique can reveal fine details of the microvasculature including endothelial nuclear orientation and distribution (Fig. 1), locations of arteriolar sphincters (Fig. 2), venous valve anatomy (Fig. 3), and vessel size, density, and branching patterns. Because casts faithfully replicate tissue vasculature, they can be used for quantitative measurements of that vasculature. The purpose of this report is to summarize and highlight some quantitative applications of vascular corrosion casting. In each example, casts were prepared by infusing Mercox, a methyl-methacrylate resin, and macerating the tissue with 20% KOH. Casts were either mounted for conventional scanning electron microscopy, or sliced for viewing with a confocal laser microscope.

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Cytochemical Specializations on the Luminal Surface of Blood Vessels in the Developing Rat Central Nervous System

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100115936 ◽

1975 ◽

Vol 33 ◽

pp. 462-463

Author(s):

R. S. Hannah ◽

T. H. Rosenquist

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Blood Vessels ◽

Alcian Blue ◽

Luminal Surface ◽

High Voltage Electron Microscopy ◽

Voltage Electron ◽

Concentration Method ◽

Endothelial Surface ◽

Cacodylate Buffer

Developing blood vessels in the rat central nervous system exhibit several unusual luminal features. Hannah (1975) used high voltage electron microscopy to demonstrate numerous ridges of endothelium, some near junctional complexes. The ridges produced troughs (which may appear as depressions) in the endothelial surface. In some areas ridges extended over the troughs, removing them from direct contact with the luminal surface. At no time were the troughs observed to penetrate the basal laminae. Fingerlike projections also extended into the lumina.To determine whether any chemical specializations accompanied the unusual morphological features of the luminal surface, we added 0.1% Alcian blue (Behnke and Zelander, 1970) to the 3% glutaraldehyde perfusate (cacodylate buffer, pH 7.4). After Alcian blue had reacted with the luminal glycocalyces, the dye was dissociated with MgCl2 via critical electrolyte concentration method of Scott and Dorling (1965). When these methods are applied together, it is possible to differentiate mucopolysaccharides (glycosaminoglycans or GAG) with the electron microscope.

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Innervation of endoneurial microvessels in human sural nerve

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100125002 ◽

1992 ◽

Vol 50 (1) ◽

pp. 920-921

Author(s):

John L. Beggs ◽

Peter C. Johnson ◽

Astrid G. Olafsen ◽

C. Jane Watkins

Keyword(s):

Blood Flow ◽

Blood Vessels ◽

Blood Supply ◽

Peripheral Nerves ◽

Sural Nerve ◽

Nerve Fibers ◽

Arterial Supply ◽

Autonomic Nerve ◽

Vasa Nervorum ◽

Endoneurial Blood Flow

The blood supply (vasa nervorum) to peripheral nerves is composed of an interconnected dual circulation. The endoneurium of nerve fascicles is maintained by the intrinsic circulation which is composed of microvessels primarily of capillary caliber. Transperineurial arterioles link the intrinsic circulation with the extrinsic arterial supply located in the epineurium. Blood flow in the vasa nervorum is neurogenically influenced (1,2). Although a recent hypothesis proposes that endoneurial blood flow is controlled by the action of autonomic nerve fibers associated with epineurial arterioles (2), our recent studies (3) show that in addition to epineurial arterioles other segments of the vasa nervorum are also innervated. In this study, we examine blood vessels of the endoneurium for possible innervation.

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Quantitative Microscopic Comparison of the Organization of the Lung in Transgenic Mice Expressing Transforming Growth Factor-α (TGF-α)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100162533 ◽

1996 ◽

Vol 54 ◽

pp. 14-15

Author(s):

C. G. Plopper ◽

C. Helton ◽

A. J. Weir ◽

J. A. Whitsett ◽

T. R. Korfhagen

Keyword(s):

Growth Factor ◽

Pulmonary Fibrosis ◽

Transgenic Mice ◽

Blood Vessels ◽

Lung Parenchyma ◽

Lung Maturation ◽

Alveolar Air ◽

Parenchymal Tissue ◽

Air Space ◽

Conducting Airways

A wide variety of growth factors are thought to be involved in the regulation of pre- and postnatal lung maturation, including factors which bind to the epidermal growth factor receptor. Marked pulmonary fibrosis and enlarged alveolar air spaces have been observed in lungs of transgenic mice expressing human TGF-α under control of the 3.7 KB human SP-C promoter. To test whether TGF-α alters lung morphogenesis and cellular differentiation, we examined morphometrically the lungs of adult (6-10 months) mice derived from line 28, which expresses the highest level of human TGF-α transcripts among transgenic lines. Total volume of lungs (LV) fixed by airway infusion at standard pressure was similar in transgenics and aged-matched non-transgenic mice (Fig. 1). Intrapulmonary bronchi and bronchioles made up a smaller percentage of LV in transgenics than in non-transgenics (Fig. 2). Pulmonary arteries and pulmonary veins were a smaller percentage of LV in transgenic mice than in non-transgenics (Fig. 3). Lung parenchyma (lung tissue free of large vessels and conducting airways) occupied a larger percentage of LV in transgenics than in non-transgenics (Fig. 4). The number of generations of branching in conducting airways was significantly reduced in transgenics as compared to non-transgenic mice. Alveolar air space size, as measured by mean linear intercept, was almost twice as large in transgenic mice as in non-transgenics, especially when different zones within the lung were compared (Fig. 5). Alveolar air space occupied a larger percentage of the lung parenchyma in transgenic mice than in non-transgenic mice (Fig. 6). Collagen abundance was estimated in histological sections as picro-Sirius red positive material by previously-published methods. In intrapulmonary conducting airways, collagen was 4.8% of the wall in transgenics and 4.5% of the wall in non-transgenic mice. Since airways represented a smaller percentage of the lung in transgenics, the volume of interstitial collagen associated with airway wall was significantly less. In intrapulmonary blood vessels, collagen was 8.9% of the wall in transgenics and 0.7% of the wall in non-transgenics. Since blood vessels were a smaller percentage of the lungs in transgenics, the volume of collagen associated with the walls of blood vessels was five times greater. In the lung parenchyma, collagen was 51.5% of the tissue volume in transgenics and 21.2% in non-transgenics. Since parenchyma was a larger percentage of lung volume in transgenics, but the parenchymal tissue was a smaller percent of the volume, the volume of collagen associated with parenchymal tissue was only slightly greater. We conclude that overexpression of TGF-α during lung maturation alters many aspects of lung development, including branching morphogenesis of the airways and vessels and alveolarization in the parenchyma. Further, the increases in visible collagen previously associated with pulmonary fibrosis due to the overexpression of TGF-α are a result of actual increases in amounts of collagen and in a redistribution of collagen within compartments which results from morphogenetic changes. These morphogenetic changes vary by lung compartment. Supported by HL20748, ES06700 and the Cystic Fibrosis Foundation.

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The molecular mechanism of mechanotransduction in vascular homeostasis and disease

Clinical Science ◽

10.1042/cs20190488 ◽

2020 ◽

Vol 134 (17) ◽

pp. 2399-2418

Author(s):

Yoshito Yamashiro ◽

Hiromi Yanagisawa

Keyword(s):

Shear Stress ◽

Blood Vessels ◽

Vessel Wall ◽

Vascular Diseases ◽

Cell Interactions ◽

Aortic Aneurysms ◽

Cyclic Stretch ◽

Mechanical Stimuli ◽

Vascular Homeostasis ◽

Matrix Cell

Abstract Blood vessels are constantly exposed to mechanical stimuli such as shear stress due to flow and pulsatile stretch. The extracellular matrix maintains the structural integrity of the vessel wall and coordinates with a dynamic mechanical environment to provide cues to initiate intracellular signaling pathway(s), thereby changing cellular behaviors and functions. However, the precise role of matrix–cell interactions involved in mechanotransduction during vascular homeostasis and disease development remains to be fully determined. In this review, we introduce hemodynamics forces in blood vessels and the initial sensors of mechanical stimuli, including cell–cell junctional molecules, G-protein-coupled receptors (GPCRs), multiple ion channels, and a variety of small GTPases. We then highlight the molecular mechanotransduction events in the vessel wall triggered by laminar shear stress (LSS) and disturbed shear stress (DSS) on vascular endothelial cells (ECs), and cyclic stretch in ECs and vascular smooth muscle cells (SMCs)—both of which activate several key transcription factors. Finally, we provide a recent overview of matrix–cell interactions and mechanotransduction centered on fibronectin in ECs and thrombospondin-1 in SMCs. The results of this review suggest that abnormal mechanical cues or altered responses to mechanical stimuli in EC and SMCs serve as the molecular basis of vascular diseases such as atherosclerosis, hypertension and aortic aneurysms. Collecting evidence and advancing knowledge on the mechanotransduction in the vessel wall can lead to a new direction of therapeutic interventions for vascular diseases.

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