Biomedical subjects

E Favari

Publications and source records attributed to E Favari.

4 recordsLinked to original sources

PubMed2002

Cellular cholesterol flux studies: methodological considerations.

Reverse cholesterol transport (RCT) is the process in which peripheral cells release cholesterol to an extracellular acceptor such as high-density lipoprotein (HDL) which then mediates cholesterol delivery to the liver for excretion. RCT represents a physiological mechanism by which peripheral tissues are protected against excessive accumulation of cholesterol. The first step in RCT is the interaction of the cell with lipoprotein particles, a process that results in both the cellular uptake and release of cholesterol. The various components of this cholesterol flux can be viewed as efflux, influx and net flux. Experimental protocols for measuring each of these components of cholesterol flux are very different, and a number of considerations are required to design experimental approaches for the quantitation of flux parameters. Although many flux studies have been conducted in the past, the recent discoveries of the scavenger receptor B1 (SR-B1) and ATP binding cassette 1 (ABCA1), which mediate the movement of cholesterol between cells and extracellular acceptors, has led to increased interest in studies of cellular cholesterol flux. The aim of this review is to present a discussion of the methodological considerations that should be evaluated during the design and analysis of cellular cholesterol flux experiments.

Animals↗

PubMed2001

Lacidipine [correction of Lalsoacidipine] modulates the secretion of matrix metalloproteinase-9 by human macrophages.

Activated macrophages within the arterial wall secrete matrix-degrading metalloproteinases (MMPs) that weaken the atherosclerotic plaque and contribute to its fissuration. Preclinical studies have shown that calcium antagonists may reduce atherogenesis in the arterial wall. In the present study we evaluated the effect of lacidipine on 92-kDa gelatinase B (MMP-9) expression in human macrophages in cultures. Cells were treated for 24 h with lacidipine and the conditioned media were analyzed. Lacidipine (1-20 microM) significantly reduced, in a dose-dependent manner, MMP-9 potential gelatinolytic capacity up to 50%. When MMP-9 expression was stimulated by treatment with phorbol esters or tumor necrosis factor-alpha, lacidipine was able to inhibit this enhanced gelatinolytic capacity up to 50 and 60%, respectively. Western blot analysis and enzyme-linked immunosorbent assay showed a reduction of MMP-9 protein actually released by cells. The addition of lacidipine in the incubation media determined no significant variation in Ca(2+) concentration. The drug did not affect MMP-9 mRNA levels, but it effectively reduced the amount of both active and total free MMP-9 secreted by human macrophages. Lacidipine reduced also the secretion of the tissue inhibitor of metalloproteinase-1 (TIMP-1); however we observed an overall reduction of the gelatinolytic activity of the cells. Finally, peritoneal macrophages, obtained from mice treated with lacidipine, showed a reduced secretion of MMP-9. Together, our data indicate that lacidipine may potentially exert an antiatherosclerotic activity by modulating the secretion of MMP-9 by macrophages. This, in addition to the previously demonstrated inhibition of cholesterol esterification, may contribute to increase plaque stability.

Animals↗

PubMed2001

Scavenger receptor class B type I affects cholesterol homeostasis by magnifying cholesterol flux between cells and HDL.

Results from several laboratories clearly indicate that expression of scavenger receptor class B type I (SR-BI) enhances the bidirectional flux of cholesterol between cells and lipoproteins. Because the activity of HMG-CoA reductase, the key enzyme in cholesterol biosynthesis, is regulated by cell cholesterol content, we designed experiments to investigate the effect of SR-BI expression on the activity of this enzyme and on net cellular cholesterol mass. In addition, we compared the function of SR-BI with its human homolog, CD36 and LIMPII analogous 1. Our experiments demonstrate that both receptors enhance the flux of unesterified or free cholesterol bidirectionally, down a concentration gradient. Receptor-mediated cholesterol flux can effectively modulate multiple aspects of cellular cholesterol metabolism, including the pool that regulates the activity of HMG-CoA reductase. We also found that constitutive expression of SR-BI alters the steady state level of cellular cholesterol and phospholipid when SR-BI-expressing cells are maintained in medium containing serum lipoproteins. All of these effects are proportional to the level of receptor on the cell surface. These data indicate that the level of SR-BI expression determines both the rate of free cholesterol flux and the steady state level of cellular cholesterol.

Animals↗

PubMed1999

Cellular toxicity of N-substituted 2,2'-dicarboxamidodiphenyldisulphides with high antimicrobial activity.

In the present paper we evaluate the cellular toxicity of some N-substituted 2,2'-dicarboxamidodiphenyldisulphides with high antimicrobial activities, in view of their potential application in humans or animals. The toxicological studies have been conducted in the murine cell line of 3T3 fibroblasts as eucaryotic cellular model. Our results have allowed the identification of a series of derivatives exhibiting antimicrobial activity and low cellular toxicity. Structure-cytotoxic activity relationships are also discussed.

3T3 Cells↗