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: Transmural concentration profiles of 125I-albumin in vivo were measured across the normal and balloon catheter-deendothelialized rabbit descending thoracic aorta as a function of time following intravenous injection. A tracer was injected 5 or 60 minutes after deendothelialization, and the animals were sacrificed after circulation times of 10, 30 or 60 minutes. The aorta was immediately excised and frozen flat between glass slides. Samples were serially sectioned parallel to the intimal surface in a refrigerated microtome, washed with trichloroacetic acid (TCA), and counted. Relative tissue concentration profiles of TCA-precipitable radioactivity from the media of control animals showed entry from both luminal and adventitial sides, as previously found with conscious normal rabbits, but spatial gradients at both luminal and medial-adventitial borders were less steep. Relative concentration levels in ballooned animals were 10- to 40-fold higher than in controls, and the profiles were flatter. Uptake rates at equivalent circulation times were greater in experiments initiated 60 minutes, as compared with 5 minutes, after deendothelialization, suggesting that progressive medial edema may have occurred following balloon injury. These results show that the intact endothelium is the dominant mass transfer resistance for 125I-albumin transport across the aortic wall. The data also suggest that the incomplete monolayer of platelets adherent to the subendothelium after balloon deendothelialization is not a substantial resistance to transport, as compared to that of the media, and that convection plays a more important role than diffusion for 125I-albumin transport across the deendothelialized aortic wall.Arteriosclerosis (Dallas, Tex.) 05/1984; 4(3):283-91. DOI:10.1161/01.ATV.4.3.283
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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 · 2.65 Impact Factor
Article: Repair in arterial tissue[Show abstract] [Hide abstract]
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 · 2.65 Impact Factor