Original Article

Phospholipase A₂ relieves phosphatidylcholine inhibition of micellar cholesterol absorption and transport by human intestinal cell line Caco-2¹

Correspondence to: Reynold Homan.

Cholesterol absorption from bile acid micelles is suppressed by phosphatidylcholine (PC) in the micelles. The effects of micellar phospholipid composition on absorption, metabolism, and secretion of lipids were examined in Caco-2 cells incubated with micelles composed of taurocholic acid, cholesterol, oleic acid, monooleoylglycerol, and phospholipid. Significant amounts of all micelle lipids were absorbed from micelles lacking phospholipid. Cholesterol absorption was accompanied by cholesterol esterification and secretion. Micellar oleic acid was also absorbed and reesterified primarily into triacylglycerol which was also secreted. Lipid absorption and secretion from micelles containing lysophosphatidylcholine (LPC) were similar to that obtained with phospholipid-free micelles. LPC was also extensively absorbed. In contrast, incubations with PC-containing micelles resulted in large reductions in the absorption, esterification, and secretion of cholesterol without significant decreases in oleic acid absorption, conversion to acylated lipids, or triacylglycerol secretion. A relatively small reduction in monoacylglycerol absorption from PC-containing micelles was detected. Retinol absorption was not affected by micellar PC. Substitution of LPC for half or more of the PC reversed the PC-dependent decrease in cholesterol absorption. Pancreatic phospholipase A₂ (pPLA₂) enhanced cholesterol absorption from PC-containing micelles. The pPLA₂-dependent increase in cholesterol absorption was inhibited by the pPLA₂ inhibitor FPL 67047XX.

The results indicate micellized cholesterol absorption by enterocytes is uniquely dependent on the elimination of micellar phosphatidylcholine and thus directly dependent on the lipolytic action of pancreatic phospholipase A₂ (pPLA₂). Consequently, pPLA₂ inhibitors may be a new and novel class of cholesterol absorption inhibitors for therapeutic use.—Homan, R., and K. L. Hamelehle. Phospholipase A₂ relieves phosphatidylcholine inhibition of micellar cholesterol absorption and transport by human intestinal cell line Caco-2. J. Lipid Res. 1998. 39: 1197–1209.

Supplementary key words: enterocyte, micelle, bile acid, phospholipid, monoacylglycerol, triacylglycerol, fatty acid, lysophosphatidylcholine, retinol, FPL 67047XX

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				S. Wang, S. K. Noh, and S. I. Koo Epigallocatechin Gallate and Caffeine Differentially Inhibit the Intestinal Absorption of Cholesterol and Fat in Ovariectomized Rats J. Nutr., November 1, 2006; 136(11): 2791 - 2796. [Abstract] [Full Text] [PDF]

				E. D. Labonte, R. J. Kirby, N. M. Schildmeyer, A. M. Cannon, K. W. Huggins, and D. Y. Hui Group 1B Phospholipase A2-Mediated Lysophospholipid Absorption Directly Contributes to Postprandial Hyperglycemia. Diabetes, April 1, 2006; 55(4): 935 - 941. [Abstract] [Full Text] [PDF]

				M. Nishimukai and H. Hara Enteral Administration of Soybean Phosphatidylcholine Enhances the Lymphatic Absorption of Lycopene, but Reduces That of {alpha}-Tocopherol in Rats J. Nutr., August 1, 2004; 134(8): 1862 - 1866. [Abstract] [Full Text] [PDF]

				L. Cai, E. R. M. Eckhardt, W. Shi, Z. Zhao, M. Nasser, W. J. S. de Villiers, and D. R. van der Westhuyzen Scavenger receptor class B type I reduces cholesterol absorption in cultured enterocyte CaCo-2 cells J. Lipid Res., February 1, 2004; 45(2): 253 - 262. [Abstract] [Full Text] [PDF]

				S. K. Noh and S. I. Koo Egg Sphingomyelin Lowers the Lymphatic Absorption of Cholesterol and {alpha}-Tocopherol in Rats J. Nutr., November 1, 2003; 133(11): 3571 - 3576. [Abstract] [Full Text] [PDF]

				K. W. Huggins, L. M. Camarota, P. N. Howles, and D. Y. Hui Pancreatic Triglyceride Lipase Deficiency Minimally Affects Dietary Fat Absorption but Dramatically Decreases Dietary Cholesterol Absorption in Mice J. Biol. Chem., October 31, 2003; 278(44): 42899 - 42905. [Abstract] [Full Text] [PDF]

				K. W. Huggins, A. C. Boileau, and D. Y. Hui Protection against diet-induced obesity and obesity- related insulin resistance in Group 1B PLA2-deficient mice Am J Physiol Endocrinol Metab, November 1, 2002; 283(5): E994 - E1001. [Abstract] [Full Text] [PDF]

				H. B. Loest, S. K. Noh, and S. I. Koo Green Tea Extract Inhibits the Lymphatic Absorption of Cholesterol and {alpha}-Tocopherol in Ovariectomized Rats J. Nutr., June 1, 2002; 132(6): 1282 - 1288. [Abstract] [Full Text] [PDF]

				N A M van Ooteghem, A Moschetta, J F Rehfeld, M Samsom, K J van Erpecum, and G P van Berge-Henegouwen Intraduodenal conjugated bile salts exert negative feedback control on gall bladder emptying in the fasting state without affecting cholecystokinin release or antroduodenal motility Gut, May 1, 2002; 50(5): 669 - 674. [Abstract] [Full Text] [PDF]

				T. Sugawara, M. Kushiro, H. Zhang, E. Nara, H. Ono, and A. Nagao Lysophosphatidylcholine Enhances Carotenoid Uptake from Mixed Micelles by Caco-2 Human Intestinal Cells J. Nutr., November 1, 2001; 131(11): 2921 - 2927. [Abstract] [Full Text] [PDF]

				Y. Jiang, S. K. Noh, and S. I. Koo Egg Phosphatidylcholine Decreases the Lymphatic Absorption of Cholesterol in Rats J. Nutr., September 1, 2001; 131(9): 2358 - 2363. [Abstract] [Full Text] [PDF]

				S. K. Noh and S. I. Koo Intraduodenal Infusion of Lysophosphatidylcholine Restores the Intestinal Absorption of Vitamins A and E in Rats Fed a Low-Zinc Diet Experimental Biology and Medicine, April 1, 2001; 226(4): 342 - 348. [Abstract] [Full Text]

				S. I. Koo and S. K. Noh Phosphatidylcholine Inhibits and Lysophosphatidylcholine Enhances the Lymphatic Absorption of {{alpha}}-Tocopherol in Adult Rats J. Nutr., March 1, 2001; 131(3): 717 - 722. [Abstract] [Full Text]

				D. Y. Hui Utility and Importance of Gene Knockout Animals For Nutritional and Metabolic Research J. Nutr., November 1, 1998; 128(11): 2052 - 2057. [Full Text]