Biomedical subjects

Ryosuke Matsuoka

Publications and source records attributed to Ryosuke Matsuoka.

3 recordsLinked to original sources

PubMed2005

Hydrolysis of micellar phosphatidylcholine accelerates cholesterol absorption in rats and Caco-2 cells.

Lymphatic recovery of cholesterol infused into the duodenum as bile salt micelles containing phosphatidylcholine (PC) was accelerated by the co-administration of phospholipase A2 in bile and pancreatic juice diverted rats. Previously we observed that cholesterol esterase, which has the ability to hydrolyze PC, caused the same effect under a similar experimental condition (Ikeda et al., Biochim. Biophys. Acta, 1571, 34-44 (2002)). Accelerated cholesterol absorption was also observed when a part of micellar PC was replaced by lysophosphatidylcholine (LysoPC) and oleic acid. Phospholipase A2 facilitated the incorporation of micellar cholesterol into Caco-2 cells in a dose-dependent manner. There was a highly negative correlation between the incorporation of cholesterol into Caco-2 cells and the content of micellar PC remaining in the culture medium. The release of cholesterol as a monomer from bile salt micelles was enhanced when a part of micellar PC was replaced with LysoPC and oleic acid. These results strongly suggest that the release of monomer cholesterol from bile salt micelles is accelerated by hydrolysis of PC in bile salt micelles and hence that cholesterol absorption is enhanced.

Animals↗

PubMed2003

Cholesterol esterase bound to intestinal brush border membranes does not accelerate incorporation of micellar cholesterol into absorptive cells.

We confirmed that cholesterol esterase accelerated the incorporation of unesterified cholesterol solubilized in bile salt micelles into differentiated Caco-2 cells under various experimental conditions. Rat pancreatic juice and bovine cholesterol esterase increased the incorporation of micellar cholesterol into rat intestinal brush border membranes. The incorporation of micellar cholesterol was not changed in the brush border membranes enriched in and depleted of cholesterol esterase. The results suggest that the accelerated incorporation of micellar cholesterol by cholesterol esterase into absorptive cells is not mediated by the enzyme bound to the brush border membranes.

Adenocarcinoma↗

PubMed2002

Cholesterol esterase accelerates intestinal cholesterol absorption.

Mechanisms of acceleration of cholesterol absorption by cholesterol esterase were investigated in various experimental conditions. Lymphatic recovery of cholesterol intubated as a micellar solution containing phosphatidylcholine (PC) into the duodenum was enhanced by the co-administration of cholesterol esterase in rats drained of bile and pancreatic juice. However, no accelerated incorporation was observed when cholesterol was solubilized in PC-depleted micelles. Cholesterol esterase dose-dependently accelerated the incorporation of cholesterol into differentiated Caco-2 cells, only when cholesterol was solubilized in PC-containing micelles. The accelerated incorporation of cholesterol into Caco-2 cells by cholesterol esterase disappeared when the enzyme was preincubated with a suicide inhibitor of cholesterol esterase. Cholesterol esterase has an activity as phospholipase A(2). When 10% of PC in bile salt micelles was replaced by lysophosphatidylcholine (lysoPC), the incorporation of cholesterol into Caco-2 cells was significantly accelerated. Cholesterol esterase enhanced the incorporation of micellar cholesterol into brush border membranes prepared from the rat jejunum. The addition of cholesterol esterase to bile salt micelles accelerated the release of micellar cholesterol in a dose-dependent manner, only when the micelles contained PC. These observations strongly suggest that cholesterol esterase hydrolyzes PC in bile salt micelles and thereby, accelerating the release of cholesterol from bile salt micelles. This may be a major cause of the acceleration of cholesterol absorption by cholesterol esterase.

Animals↗