Hydrogenated phosphatidylcholine supplementation reduces hepatic lipid levels in mice fed a high-fat diet

The ability of the fatty acid composition of dietary phosphatidylcholine (PC) to affect hepatic lipid levels was investigated in C57BL/6 mice (n=8-10 per group) by feeding: (1) a high-fat semi-purified diet (HF), (2) HF diet supplemented with 1.25 wt% soy PC (SPC), (3) HF with 1.25 wt% hydrogenated soy PC (SPCH), (4) HF with 1.25 wt% egg PC (EPC), and (5) HF with 1.25 wt% hydrogenated egg PC (EPCH). The polyunsaturated fatty acid content (C18:2+C18:3+C20:4) of soy, egg and hydrogenated PC was 70%, 20% and 0%, respectively. Total liver lipid was significantly lower in SPCH and EPCH vs. HF (8.7 ± 0.1 and 8.5 ± 0.5 vs. 11.8 ± 0.6g/100, P<0.05), but not in SPC or EPC. SPCH and EPCH had significantly lower levels of hepatic cholesterol (-52% and -53% vs. HF, respectively). Bioactive lipids (i.e., sphingomyelin and ceramide) were also lower in the liver of SPCH and EPCH rather than in SPC or EPC. Hepatic expression of genes controlling fatty acid synthesis and catabolism were not significantly affected by dietary PC. However, hepatic expression of HMGCR, LDLR and SREBP2 was higher and that of ABCA1, ABCG5 and ABCG8 was reduced in SPCH and EPCH vs. HF. These results demonstrate that hydrogenated PC supplementation reduces hepatic lipid levels in mice fed a high-fat diet supporting the concept that the ability of dietary PC to lower hepatic lipid levels is not due to its content of polyunsaturated fatty acids.