ISSN:
0021-9541
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
During the development of atherosclerotic and fibromuscular proliferates/lesions, smooth muscle cells (SMC in the media, particularly near the lumen, are activated to migrate into the intima, where they continue to proliferate to form an intimal thickening. It is to date unclear whether SMCs situated adjacent to the adventitia possess a lower capacity to proliferate because they are a special subpopulation of medial SMCs or because the adventitia excerts an inhibitory effect. We have, therefore, developed an in vitro system whereby we have attempted to clear up this uncertainty. The following observations were made from the in vitro experiments:Media-explants from rabbit aorta were laid on a polycarbonate filter with pores 5 μm in diameter. The SMCs migrated through the pores and formed a fibromuscular proliferate on the other side of the filter.Endothelial cells were seeded on one side of the filter before media-explants were laid on the other side of the filter. The confluent endothelium inhibited migration of SMCs through the filter pores.Media-explants were placed between two polycarbonate filters (pores 5 μm diameter). In this “sandwich” arrangement SMCs migrated through both filters, i.e., in both directions. The quantity of migrating and proliferating cells through both filters was almost identical. This suggests that there is no difference in the migratory and proliferate capacity of SMCs in the inner and outer layers in the media of arteries.To investigate the influence of the adventitia on medial SMCs, media-explants were placed between a lower (5 μm) and an upper (0.2 μm) filter adventitia-explants were laid above the media-explants. The 0.2 μm filter prevented migration of SMCs from the media-explant into the adventitia and migration of fibroblasts from the adventitia into the media. Interestingly, the adventitial tissue inhibited proliferation of SMCs at the abluminal and migration and proliferation at the luminal side of the media-explant; the number of cells migrating through the 5 μm pores at the luminal side was diminished, suggesting that the adventitial tissue has an antiproliferative influence on SMCs. Moreover, it was found that in media-explants near the filter with adventitia, the medial SMCs were in a better preserved condition than at the de-endothelialised luminal side.As a control, cultures consisting of media-explants were incubated without filters (i.e., explant organ cultures). The proliferates in the concavity (luminal side) exhibited a pattern of proliferating SMCs different from that of the cells at the abluminal convexity. This finding indicates that the different texture of vessel walls near the adventitia and near the lumen may also influence cell migration and proliferation.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1041470302
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