Jean-Paul Gouygou

Lipid composition of cultured endothelial cells in relation to their growth

Human endothelial cells in culture were examined in different growth conditions. The human endothelial cell line, EA.hy 926 cell line, was used and cells were studied either in exponential growth phase, at confluence, or growth-arrested by serum deprivation. Phospholipids were separated and analyzed by high-performance thin-layer chromatography, and their fatty acids were quantified by gas-liquid chromatography. No significant differences in the phospholipid distributions were found between exponentially growing and confluent endothelial cells in which phosphatidylcholine (PC) represented the major phospholipid. In comparison, serum-deprived cells exhibited higher proportions of sphingomyelin and lower content of PC. We also found that among the total lipids, cholesterol level for dividing endothelial cells was lower than for cells growth-arrested either by serum deprivation or by contact inhibition at confluence. The global fatty acid distribution was not affected by the growth conditions. Thus, oleate (18∶1n−9 and 18∶1n-7), palmitate (C16∶0), and stearate (C18∶0) were the main components of endothelial cell membranes. However, the fatty acid distributions obtained from each phospholipid species differed with the growth status. Altogether, the data indicated that subtle modulations of endothelial cell metabolism appear upon cell growth. The resulting membrane-dependent cellular functions such as cholesterol transport and receptor activities can be expected to be relevant for lipid trafficking within the vessel wall in vitro and in vivo.

New trends in phospholipid class composition of marine sponges.

The exceptional ability of marine sponges to adapt to often drastic changes of their environments could be due to special structural features in cell membranes, including firstly phospholipids (PL). Thus, PL class composition was investigated in marine sponges (22 species from 19 genera to 15 families) originating from various locations (East Atlantic, North Atlantic, South-West Pacific, Mediterranean Sea, Red Sea, Arabian-Persian Gulf). The quantitative determination of PL class composition was obtained by high-performance thin-layer chromatography (HPTLC) with scanning densitometry of the different spots. Previous reports have shown phosphatidylethanolamine (PE) as the major PL class in marine sponges, followed by phosphatidylcholine (PC), while other papers described PC as a minor class and even lacking. This survey found PE as the major PL class in only two species, while PC was the major class in 13 species including a calcareous one. The great abundance of bacteria in some sponges was evidenced from the relatively high proportions of particular PL classes. Various PL distributions were observed even for the sponge species collected in the same area and belonging to the same genus. Thus, no clear rule on PL composition in marine sponges can be stated to date.

P067 Effets d’un apport faible en huile de poisson sur la composition lipidique du foie, du muscle et du tissu adipeux chez le rat

Introduction et but de l’etude Le but de ce travail etait d’etudier, chez le rat, les effets d’un regime faiblement enrichi en huile de poisson (HP), sur le profil des acides gras (AG) des phospholipides (PL) et des lipides neutres (LN) du foie, du muscle et du tissu adipeux (TA). Materiel et methodes Materiels et Methodes : 24 rats Wistar mâles ont ete soumis pendant 5 semaines a un regime contenant 6,6 % de lipides (poids/poids) a base d’arachide-colza (regime AC), ou d’un melange AC (4,4 %) + HP (2,2 %) (regime HP). La composition en AG des regimes etait : AG satures (15 vs 20,5 %, AC vs HP) ; 18:1 n-9 (59,8 vs 48.1 %, AC vs HP), AGPI n-6 (20,9 vs 23,4 %, AC vs HP), EPA+DHA (0 vs 7,6 %, AC vs HP). Apres extraction, la separation des LN et des PL a ete effectuee par chromatographie liquide sur micro-colonne de silice. La composition en AG de ces 2 fractions a ete determinee par GC-MS. Resultats Resultats (moy±sem ; Mann-Whitney) : Dans les LN, Le contenu en 18:1 n-9 decroit (– 17.5%, p Conclusions Un regime faiblement enrichi en HP permet l’incorporation, dans les PL membranaires, des AGPI-LC n-3 au detriment du 20:4 n-6, mais la somme de ces 3 AG reste constante temoignant du maintien du degre d’insaturation. La composition en AG des LN reflete la composition du regime.