Influence of n-3 fatty acid supplementation on the endogenous activities of plasma lipases

Abstract

The aim of these studies was to explore the possibility that enhanced triacylglycerol clearance may contribute to the hypotriacylglycerolemic effect of n-3 fatty acids in humans. Healthy subjects (n = 20) and hypertriacylglycerolemic patients (n = 6) were given a placebo (olive oil, OO) or a fish-oil concentrate (FOC; 41% eicosapentaenoic acid and 23% docosahexaenoic acid) in two, independent, randomized, blind trials. For the healthy subjects, the FOC treatment period was 3 wk long and FOC intakes were 5 g/d. For the patients, treatment periods were 4 wk long and dosages were 5 g.70 kg body wt-1.d-1. Washout periods were 2-4 wk for both groups. Blood samples were drawn at the end of each phase and analyzed for plasma lipids, lipoproteins, and endogenous (nonheparin-stimulated) activities of lipoprotein lipase (LPL) and hepatic lipase (HL). In the healthy subjects the FOC decreased plasma triacylglycerol concentrations by 18% (P < 0.01), whereas in the patients concentrations were reduced by 35% (P < 0.05). Low-density-lipoprotein-cholesterol concentrations increased by 25% in the latter group (P = 0.06). FOC increased the endogenous activities of LPL and HL by 62% and 68%, respectively (P < 0.0001), in the healthy subjects, but only LPL in the patients (65%, P < 0.005). These data suggest that endogenous lipase activities may be altered by nutritional interventions, and further, that accelerated lipolysis could contribute, at least in part, to the observed effects of n-3 fatty acids on human lipoprotein metabolism.

The quantitation of lipoprotein lipase mRNA in biopsies of human adipose tissue, using the polymerase chain reaction, and the effect of increased consumption of n-3 polyunsaturated fatty acids

“…In addition, the release of LPL after heparin administration represents a single point, unphysiological stimuli. The negative correlation between PHLA and TAG-AUC, in the present study, ®ts with the ®ndings of Harris et al (1997) comparing LPL activity and fasting TAG levels. The relationship between PHLA and TAG-AUC suggest that PHLA levels re¯ect recent exposure to the substrate, plasma TAG, with the result that high levels of activity effectively clear TAG from the plasma.…”

“…In addition, we have shown that ®sh oils stimulate and activate LPL; human volunteers had signi®cantly raised post-heparin LPL activity when fed a ®sh oil-containing meal compared with a mixed oil meal when measured 12 h after the meal was consumed (Zampelas et al, 1994). This work has recently been con®rmed by the ®ndings of Harris et al (1997). We have also shown signi®cantly increased LPL gene expression in rat epididymal adipose tissue following a ®sh oil diet (Murphy et al, 1993).…”

Regulatory Effects of HMG CoA Reductase Inhibitor and Fish Oils on Apolipoprotein B-100 Kinetics in Insulin-Resistant Obese Male Subjects With Dyslipidemia

“…Decreased VLDL particle number would conceivably lead to a greater proportion of VLDL being converted into LDL. Moreover, these effects may entail enhanced lipolysis via the stimulation of lipoprotein lipase activity, as reported elsewhere (38).…”

ApoE Polymorphism and Fish Oil Supplementation in Subjects With an Atherogenic Lipoprotein Phenotype

“…A limited number of human studies have generally failed to show an increased postheparin LPL activity with high fish oil diets, 17,18,56,59 although 2 recent reports have found significant increases. 60,61 Zampelas et al 60 have shown elevated postheparin LPL activity 9 hours after meals enriched with n-3 PUFA compared with saturated fatty acid, and Harris et al 61 observed a 62% increase in endogenous LPL activity in healthy volunteers after 3 weeks of fish oil supplementation (5 g/d). Several mechanisms may be responsible for this observed increase in LPL activity, including changes in LPL gene expression, transport of newly synthesized LPL to the vascular wall, or a change in NEFA metabolism.…”