TY - JOUR
T1 - Effects of saturated, mono-, and polyunsaturated fatty acids on the secretion of apo B containing lipoproteins by Caco-2 cells
AU - van Greevenbroek, M.M.J.
AU - van Meer, G.
AU - Erkelens, D.W.
AU - de Bruin, T.W.A.
PY - 1996
Y1 - 1996
N2 - We studied the effects of addition of physiological concentrations (0.5 mM) of fatty acids i.e., palmitic (16:0), stearic (18:0), oleic (18:1) and linoleic acid (18:2) on lipoprotein secretion by polarized Caco-2 cells. With saturated fatty acids, secreted lipoproteins were at IDL/LDL density, 1.009 <d <1.068 g/ml. The numbers of secreted lipoproteins, expressed as secreted apolipoprotein (apo) B, were comparable to control without fatty acid (palmitic acid, 551 ± 185; stearic acid, 629 ± 304 and control, 504 ± 176 ng apo B/4.7 cm2 filter). With unsaturated fatty acids, apo B containing lipoproteins were secreted at chylomicron/VLDL density (d <1.006 g/ml). Oleic acid caused a two-fold higher secretion of apo B than control (1058 ± 87 vs. 504 ± 176 ng/4.7 cm2 filter, P <0.001). The increase in apo B secretion was attributed to a specific increase in apo B-48. Unsaturated fatty acid caused a two-fold higher secretion of triglyceride than saturated fatty acids but incorporation of newly synthesized lipid into the secreted lipoproteins, measured by incorporation of a fatty acid marker, was 10- to 20-fold higher, indicating preferential translocation of unsaturated triglycerides into lipoproteins. Mixtures rich in either polyunsaturated, monounsaturated, or saturated fatty acids, resembling nutritional fat and oils, were capable of a two-fold stimulation of secretion of apo B containing triglyceride-rich lipoproteins. The triglyceride/apo B ratio in the basolateral medium was higher with the monounsaturated 'olive oil' mixture (12 250 ± 2000 mol/mol) than with the polyunsaturated 'corn oil' mixture (7830 ± 2480 mol/mol) and incorporation of newly synthesized lipid into the secreted lipoproteins was 1.5-fold higher as well. In conclusion, unsaturated fatty acids were most potent in stimulating the secretion of apo B by specifically increasing apo B-48 secretion. Unsaturated triglycerides, that contain mainly oleic acid, were more efficiently incorporated into lipoproteins than saturated triglycerides, suggesting preferential translocation by microsomal triglyceride transfer protein.
AB - We studied the effects of addition of physiological concentrations (0.5 mM) of fatty acids i.e., palmitic (16:0), stearic (18:0), oleic (18:1) and linoleic acid (18:2) on lipoprotein secretion by polarized Caco-2 cells. With saturated fatty acids, secreted lipoproteins were at IDL/LDL density, 1.009 <d <1.068 g/ml. The numbers of secreted lipoproteins, expressed as secreted apolipoprotein (apo) B, were comparable to control without fatty acid (palmitic acid, 551 ± 185; stearic acid, 629 ± 304 and control, 504 ± 176 ng apo B/4.7 cm2 filter). With unsaturated fatty acids, apo B containing lipoproteins were secreted at chylomicron/VLDL density (d <1.006 g/ml). Oleic acid caused a two-fold higher secretion of apo B than control (1058 ± 87 vs. 504 ± 176 ng/4.7 cm2 filter, P <0.001). The increase in apo B secretion was attributed to a specific increase in apo B-48. Unsaturated fatty acid caused a two-fold higher secretion of triglyceride than saturated fatty acids but incorporation of newly synthesized lipid into the secreted lipoproteins, measured by incorporation of a fatty acid marker, was 10- to 20-fold higher, indicating preferential translocation of unsaturated triglycerides into lipoproteins. Mixtures rich in either polyunsaturated, monounsaturated, or saturated fatty acids, resembling nutritional fat and oils, were capable of a two-fold stimulation of secretion of apo B containing triglyceride-rich lipoproteins. The triglyceride/apo B ratio in the basolateral medium was higher with the monounsaturated 'olive oil' mixture (12 250 ± 2000 mol/mol) than with the polyunsaturated 'corn oil' mixture (7830 ± 2480 mol/mol) and incorporation of newly synthesized lipid into the secreted lipoproteins was 1.5-fold higher as well. In conclusion, unsaturated fatty acids were most potent in stimulating the secretion of apo B by specifically increasing apo B-48 secretion. Unsaturated triglycerides, that contain mainly oleic acid, were more efficiently incorporated into lipoproteins than saturated triglycerides, suggesting preferential translocation by microsomal triglyceride transfer protein.
U2 - 10.1016/0021-9150(95)05712-9
DO - 10.1016/0021-9150(95)05712-9
M3 - Article
SN - 0021-9150
VL - 121
SP - 139
EP - 150
JO - Atherosclerosis
JF - Atherosclerosis
IS - 1
ER -