The association of endothelial and smooth muscle cells to elastic laminae in the developing mouse aortic wall was investigated by electron microscopy and immunohistochemistry. Early in development, bundles of contractile filaments traverse the long axis of the cell obliquely to anchor in membrane-associated dense plaques on either side. From these sites, microfibrils extend in the same direction to link the cell to the adjacent elastic laminae. The microfibrils become infiltrated with elastin to form elastin extensions, which together with the intracellular contractile filaments bundles, forms a "contractile-elastic unit". The ordered arrangement of contractile-elastic units revealed in the adult vessel provides a mechanism for the transmission of tension throughout the vessel wall. During development, endothelial cells are similarly connected to the subjacent elastic lamina by filamentous structures. These "endothelial cell connecting filaments" show morphological feature similar to microfibrils. Immunolocalization of fibrillin, a constituent protein of microfibrils, to the connecting filaments provides further evidence for their microfibrillar nature. These results suggest that microfibrils may play an important role in cell anchorage and the maintenance of tissue integrity. A longterm radioautographic study was performed to provide quantitative data concerning the stability of aortic elastin. Results from this study demonstrate the remarkable longevity of elastin in the aortic wall and suggest that, like elastin, cell to elastic lamina connections remain stable throughout development and exist as functional structures in the adult vessel.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.39360 |
| Date | January 1992 |
| Creators | Davis, Elaine C. (Elaine Caroline) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Anatomy.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001276835, proquestno: NN74947, Theses scanned by UMI/ProQuest. |
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