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Biosynthesis of platelet-activating factor and its 1O-acyl analogue by liver fat-storing cells.
- Source :
-
Gastroenterology [Gastroenterology] 1994 May; Vol. 106 (5), pp. 1301-11. - Publication Year :
- 1994
-
Abstract
- Background/aims: Platelet-activating factor (PAF) is an important mediator of proinflammatory cell-to-cell interactions with powerful vasoactive properties. We evaluated the biosynthesis of PAF by cultured human fat-storing cells (FSC), liver-specific pericytes involved in the inflammatory and fibrogenic process of liver tissue.<br />Methods: PAF synthesis was evaluated by measuring [3H]acetate incorporation under basal conditions and upon stimulation with A23187, thrombin, and lipopolysaccharide. Further analysis of PAF species synthesized by FSC was performed using gas chromatography/mass spectrometry.<br />Results: All stimuli induced a significant increase of basal PAF synthesis by FSC. Further analysis showed that > 50% of the newly synthesized PAF species was secreted whereas the remaining fraction was cell-associated. PAF species produced by FSC were able to induce aggregation of rabbit washed platelets with an effectiveness correspondent to 10(-9) mol/L authentic PAF. Gas chromatography/mass spectrometry analysis revealed that a large percentage (74%) of PAF-like lipids synthesized by FSC consisted of 1O-acyl PAF. Finally, stimulation of FSC with PAF caused an increase in cytosolic free calcium, thus suggesting a possible involvement of this pericyte in the well-known effects of PAF on portal pressure.<br />Conclusions: These results expand the available knowledge concerning the role of PAF in conditions characterized by extensive activation and damage of the liver sinusoidal endothelium and decreased hepatic scavenger activity.
Details
- Language :
- English
- ISSN :
- 0016-5085
- Volume :
- 106
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Gastroenterology
- Publication Type :
- Academic Journal
- Accession number :
- 8174891
- Full Text :
- https://doi.org/10.1016/0016-5085(94)90023-x