Uptake and metabolism of structured triglyceride by Caco-2 cells: reversal of essential fatty acid deficiency.
Structured lipids have been proposed as efficient vehicles for the supplementation of essential fatty acids (EFA) to patients with malabsorption. We investigated how a novel structured triglyceride (STG), containing purely octanoic acid in the sn-1/sn-3 and [14C]linoleic acid in the sn-2 positions, was incorporated into different lipid classes in Caco-2 cells. We also evaluated the contribution of gastric lipase in the uptake and metabolism of [14C]linoleic acid from the STG. We furthermore determined the potential of the STG to correct EFA deficiency induced in Caco-2 cells. The absorption of STG by Caco-2 cells was significantly greater compared with that of triolein. The addition of human gastric lipase significantly enhanced cellular uptake of the labeled substrate, reflecting the stereoselectivity of gastric lipase to hydrolyze medium chain FA. Analysis of the intracellular lipids synthesized revealed a predominance of phospholipids-monoglycerides. Most of the radioactivity in the lipoproteins isolated from Caco-2 cells was recovered in TG-rich lipoproteins (45%) and to a lesser extent in the high-density lipoprotein (36%) and low-density lipoprotein (17%) fractions. The administration of STG to Caco-2 cells rendered EFA deficient produced a marked increase of the cellular level of linoleic and arachidonic acids. This resulted in a lower ratio of 20:3(n-9) to 20:4(n-6), reflecting the correction of EFA deficiency in Caco-2 cells. Our data demonstrate that STG, in the presence of gastric lipase, have beneficial effects on lipid incorporation, lipoprotein production, and EFA status, utilizing Caco-2 cells as a model of EFA deficiency.
Spalinger
J H
JH
Division of Gastroenterology and Nutrition, Centre de Recherche, Hôpital Sainte-Justine, University of Montreal, Montreal, Quebec, H3T 1C5 Canada.
Seidman
E G
EG
Lepage
G
G
Ménard
D
D
Gavino
V
V
Levy
E
E
D001692:Biological Transport; D018938:Caco-2 Cells; D002250:Carbon Radioisotopes; D002462:Cell Membrane / Q000378:metabolism; D004075:Diglycerides / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D005228:Fatty Acids, Essential / Q000172:deficiency / Q000378:metabolism*; D005989:Glycerides / Q000378:metabolism; D006801:Humans; D007408:Intestinal Absorption; D019787:Linoleic Acid / Q000378:metabolism*; D008049:Lipase / Q000378:metabolism; D008074:Lipoproteins / Q000378:metabolism*; D008075:Lipoproteins, HDL / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000378:metabolism; D008079:Lipoproteins, VLDL / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism*; D014304:Triolein / Q000378:metabolism
D002250:Carbon Radioisotopes; D004075:Diglycerides; D005227:Fatty Acids; D005228:Fatty Acids, Essential; D005989:Glycerides; D008074:Lipoproteins; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D014280:Triglycerides; D014304:Triolein; D019787:Linoleic Acid; D008049:Lipase