Abnormal deposition of extracellular matrix proteins by cultured smooth muscle cells from human varicose veins

The aim of the present study was to verify whether the modifications of the extracellular matrix, described in varicose veins, are also present in cultures of smooth muscle cells from human varicose veins. The accumulation of collagen type Iii and fibronectin was determined by immunofluorescence in cultures of smooth muscle cells at passage 2-3 during the proliferation phase. After 5 days of culture, the immunostaining of both collagen type Iii and fibronectin was weaker in cells from varicose than in those of control veins while the expression of collagen type Iii and fibronectin messenger ribonucleic acids was not significantly different. Collagen type I and Iii synthesis were quantified by tritiated proline incorporation in control and varicose cell layers at postconfluence. Collagen type I deposition was similar in both types of cell layers while collagen type Iii was decreased in cell layers from varicose veins. Matrix metalloproteinases (mmps) and their inhibitors (timps) were also quantified by enzyme immunoassays in supernatants from smooth muscle cell cultures at postconfluence. No significant difference was observed in the synthesis of any of the Mmps (- 1, -2 and -9) or their inhibitors (- 1 and -2) tested. These data illustrate that smooth muscle cells cultured from varicose veins deposit less collagen type Iii and fibronectin than control cells despite comparable levels of mrnas for these proteins suggesting dysregulation of posttranslational steps in the synthesis of both proteins by smooth muscle cells from varicose veins.link_to_subscribed_fulltex

Localization of angiotensin-converting enzyme (ACE) mRNA in rabbit gastric mucosa by in situ hybridization.

International audienceIn a previous study we showed, by immunohistochemical analysis on rabbit fundic mucosa, that in addition to its usual presence on the luminal plasma membrane of endothelial cells, angiotensin converting-enzyme (ACE) was localized inside granules of surface and neck mucous cells and within granules of chief cells. The aim of the present study was to localize ACE mRNA in cells of the rabbit fundic mucosa by in situ hybridization with a 35S-labeled probe. This probe was a cDNA fragment (406 BP) encoding a portion of the rabbit ACE mRNA obtained by reverse transcription followed by polymerase chain reaction on total RNA extracted from fundic mucosa. ACE mRNAs were detected in mucous and chief cells and in endothelial cells of the mucosal vasculature. These results are in complete agreement with our prior studies which showed by immunohistochemical analysis that ACE is present in these cells. Our findings therefore suggest that ACE previously detected in epithelial cells of the rabbit gastric mucosa is actually synthesized within these cells