Cholesteryl ester species differently elevate plasma cholesterol in hamsters.

Area of Science:

• Lipid Metabolism
• Nutritional Biochemistry
• Cardiovascular Research

Background:

• Cholesterol homeostasis is critical for health.
• Dietary cholesterol absorption involves various ester species.
• Understanding the impact of different cholesteryl ester (CE) species is crucial for dietary recommendations.

Purpose of the Study:

• To investigate the differential effects of free cholesterol (C) and specific CE species (cholesteryl palmitate, cholesteryl stearate, cholesteryl oleate, cholesteryl linoleate) on lipid profiles in hamsters.
• To elucidate the mechanisms underlying the varying plasma cholesterol-raising activities of different CE species.

Main Methods:

• Administration of specific dietary CE species to hamsters.
• Analysis of plasma lipid profiles, including total cholesterol (TC), HDL-C, non-HDL-C, and triacylglycerols (TG).
• Assessment of CE hydrolysis rates using pancreatic cholesterol esterase.
• Fecal cholesterol analysis and intestinal gene expression profiling (NPC1L1, ACAT2, MTP) via RT-PCR.

Main Results:

• Dietary CE species differentially affected plasma TC levels; cholesteryl oleate (CO) markedly increased TC, while cholesteryl stearate (CS) showed a lesser increase.
• Cholesteryl stearate (CS) exhibited poor hydrolysis by pancreatic cholesterol esterase compared to cholesteryl oleate (CO).
• CS-fed hamsters had higher fecal cholesterol excretion and showed down-regulation of intestinal NPC1L1, ACAT2, and MTP expression.

Conclusions:

• The plasma cholesterol-raising activity of dietary CE species is influenced by their intestinal hydrolysis rates.
• The limited cholesterol-raising effect of cholesteryl stearate (CS) is associated with reduced intestinal absorption and transport, mediated by down-regulation of key genes (NPC1L1, ACAT2, MTP).
• These findings highlight the importance of CE species composition in dietary cholesterol's impact on lipid metabolism.