Repair in arterial tissue. The role of endothelium in the permeability of a healing intimal surface. Vital staining with Evans blue and silver-staining of the aortic intima after a single dilatation trauma.

ABSTRACT The role of the endothelium as a factor determining the permeability of a healing aortic intima after a severe mechanical lesion in the rabbit was studied by vital staining with Evans blue, by surface light microscopy after silver-staining, fluorescence microscopy and by other methods. Endothelium to develop from pre-existing endothelium in the mouths of intercostal arteries and at the borders of the lesion, remained unstained by vital staining, whereas denuded surfaces as well as pseudo-endothelium, probably derived from smooth muscle cells in the neointima, were intensely coloured. There was a general tendency towards a decreasing permeability of the aortic wall throughout an experimental period of 6 months. The determinant factor in the decreasing permeability was the presence of genuine endothelium, but changes in the endothelium, probably in the form of differentiation of intercellular junctions and changes in the connective tissue in the deeper layers, seemed to be additional factors which influenced the permeability.

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    ABSTRACT: Immunoperoxidase staining for fibronectin in ethanol- and formaldehyde-fixed, normal and healing arterial tissue is presented. Proteolytic digestion of sections fixed in formaldehyde increased the staining intensity for fibronectin in media from normal thoracic aorta and in neo-intima covered with endothelium, and had a similar effect on media from thoracic aortae with an embolectomy catheter lesion. The staining reaction for fibronectin in formaldehyde-fixed neo-intima covered with aortic smooth muscle cells was strong and almost independent of proteolytic digestion. In re-endothelialized neo-intima with a high content of proteoglycans a masking effect was observed, probably depending on poor access of immunoglobulins to fibronectin. The masking effect observed in non-re-endothelialized neo-intima with a low content of proteoglycans was much weaker. The correlation between the choice of fixative and unmasking of antigenic determinants by proteases is discussed.
    Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 12/1982; 399(3):307-316. DOI:10.1007/BF00612948 · 2.56 Impact Factor
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    ABSTRACT: The thoracic aortae from 11 rabbits that survived a single severe dilatation injury for 2 years were studied by vital staining with Evans blue, immunohistochemistry and transmission electron microscopy. Our results have shown almost total restitution of the thoracic aorta. Six of the 11 rabbits submitted to an injury had no blue-stained areas, indicating total reendothelialization. Five rabbits had a few blue areas often on the ventral side of the aorta. The reendothelialization from the first to the seventh pair of intercostal arteries ranged from 82% to 100%. There was intimal thickening inside the original internal elastic lamina in both white and blue areas. All blue areas had a surface composed of smooth muscle cells. Reendothelialized areas consisted of mature endothelium, reticular basal membrane, layered smooth muscle cells and an extracellular matrix consisting of pre-elastin, elastin, collagen and proteoglycans. An effective barrier had apparently been formed against penetration of macromolecules, judged from the absence of fibrinogen/fibrin and unmasked fibronectin. Intimal thickenings without endothelial cover were covered with smooth muscle cells without intercellular junctions. Our results indicate that an extracellular matrix of fibrin and fibronectin plays a role in forming an intimal thickening, and it is suggested that proteoglycans may modulate the biological role of the extracellular matrix in the healing process.
    Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 10/1991; 418(6):523-530. DOI:10.1007/BF01606503 · 2.56 Impact Factor
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    ABSTRACT: Following an in vivo lesion of the rabbit thoracic aorta, endothelial regeneration was studied in silver-stained specimens from en face organ cultures of aortic segments with and without intercostal arteries. The in vivo lesion had been inflicted by an embolectomy catheter.Our results confirmed that endothelium regenerates from preexisting endothelium around the mounths of the intercostal arteries. A conspicuous observation was the orientation pattern of endothelial cells during regeneration. Transmission electron microscopy suggests that the cell cytoskeleton plays a role in the regulation of regeneration. The organ culture technique described, complementary to in vivo and in vitro investigations with cell cultures, seems to be a valuable tool in further investigations on factors involved in the repair of arterial tissue.
    Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 11/1977; 375(4):257-262. DOI:10.1007/BF00427057 · 2.56 Impact Factor