Dietary myristic acid modifies the HDL-cholesterol concentration and liver scavenger receptor BI expression in the hamster

Abstract

The influence of myristic acid in a narrow physiological range (0·5 to 2·4 % of total dietary energy) on the plasma and hepatic cholesterol metabolism was investigated in the hamster. The hamsters were fed on a diet containing 12·5 g fat/100 g and 0·05 g cholesterol/100 g with 0·5 % myristic acid (LA diet) for 3 weeks (pre-period). During the following 3 weeks (test period), they were divided into four dietary groups with 0·5 % (LA), 1·2 % (LM), 1·8 % (ML) or 2·4 % (M) myristic acid. Finally, half the hamsters in each group were again fed the LA diet for another 3 weeks (post-period). At the end of the test period, the hepatic expression of the scavenger receptor BI (SR-BI) was lower in the LM, ML and M groups than in the LA group whereas the hepatic cholesteryl ester concentration was higher. Cholesterol 7α hydroxylase activity was lower in the ML and M groups than in the LA and LM groups while the sterol 27 hydroxylase and 3-hydroxy-3-methyl glutaryl coenzyme A reductase activities were not modulated by dietary myristic acid. This is the first time a negative correlation has been observed between the HDL-cholesterol concentration and the hepatic mass of SR-BI (r-0·69;P<0·0001) under physiological conditions. An inverse linear regression was also shown between SR-BI and the percentage of myristic acid in the diet (r-0·75;P<0·0001). The hepatic mass of SR-BI in the M group had increased at the end of the post-period compared with the test-period values. The present investigation shows that myristic acid modulates HDL-cholesterol via a regulation of the SR-BI expression.

Assessment of hepatoprotective potential of N. indicum leaf on haloalkane xenobiotic induced hepatic injury in Swiss albino mice

“…Methylparaben showed antioxidative activity and prevented lipid peroxidation in 6-hydroxydopamine-induced animals [54]. The predominant food component tetradecanoic acid (myristic acid) showed free radical scavenging activity [55] and cholesterol modulating activity in vivo [56]. Vaccenic acid demonstrated convincing hypolipidemic activity by decreasing hepatic lipogenesis in experimental rats [57].…”

Moderate Dietary Intake of Myristic and Alpha‐Linolenic Acids Increases Lecithin‐Cholesterol Acyltransferase Activity in Humans

“…Original data from Pownall et al [8] have determined how molecular structure of PC independently regulate cholesteryl ester formation via LCAT action. Concerning dietary myristic acid (MA, 14:0), Loison et al [10] have recently reported in hamsters a positive correlation between plasma HDL concentration and the amount of MA in the diet.…”

Short Chain Saturated Fatty Acids Decrease Circulating Cholesterol and Increase Tissue PUFA Content in the Rat

“…Myristic acid has long been considered as having played a major role in the increase in blood cholesterol level in animals and humans, when provided at high level, exceeding 4% of dietary energy [9,10]. However, when its dietary level is moderate (1.0-2.5% of dietary energy) no evidence of deleterious effects of this specific fatty acid has been reported [11][12][13][14]25]. In humans, a moderate supply of myristic acid (1.8% of daily energy) was shown to improve lecithin cholesterol acyltransferase (LCAT) activity, which is considered beneficial in terms of HDL cholesterol concentration and reverse cholesterol transport [36].…”

“…For instance, short and medium chain SFA have been shown to have no increasing effect on plasma cholesterol in humans [8]. Myristic acid has deleterious effects on blood cholesterol level in animals and humans when provided at high level exceeding 4% of dietary energy [9,10], but these negative effects disappear when its dietary level is moderate (1.0-2.5% of dietary energy) [11][12][13][14]. Stearic acid has also been demonstrated to be neutral on plasma cholesterol concentrations [15] and to have no negative effect on thrombotic markers in humans [16].…”