An obesogenic diet enriched with blue mussels protects against weight gain and lowers cholesterol levels in C57BL/6 mice.

Obesity is linked to several health complications, such as cardiovascular disease, insulin resistance, and hypertension. Dyslipidemia in obesity is one of the prime causes for health complications. We have previously shown that blue mussels (BM) are a rich source of omega (n)-3 polyunsaturated fatty acids (PUFA) and increase the mRNA expression of peroxisome-proliferator activated receptor and adiponectin, thereby inducing anti-obesity and insulin sensitizing effects in vitro. However, the in vivo effects of BM on obesity and metabolic regulation are not known. We hypothesized that dietary intake of BM will prevent weight gain and improve lipid profile of C57BL/6 mice fed a high-fat diet (HFD). Mice were fed a HFD supplemented with 5% w/w BM (BM-HFD) for 4 weeks, and then switched to a HFD for 4 weeks. Mice fed a BM-HFD showed significantly lower body weight gain and abdominal fat, compared to the HFD. Furthermore, a BM-HFD significantly reduced plasma and hepatic total and low-density lipoprotein (LDL)-cholesterol, compared to HFD. The decrease in cholesterol levels coincided with inhibition of hepatic sterol regulatory element-binding protein-2 and HMG-CoA reductase mRNA expression, and an increase in LDL-receptor gene expression in the BM-HFD group, compared to the HFD group. In conclusion, our findings have established that BM reduces body weight gain in mice. BM may have potential to lower cholesterol levels by inhibiting cholesterol synthesis, thereby protecting against obesity and perhaps heart disease.

A high fat-high sucrose diet enriched in blue mussels protects against systemic inflammation, metabolic dysregulation and weight gain in C57BL/6 mice.

High fat-high sucrose (HF-HS) diet, known as the western diet, has been shown to induce the onset of obesity via increasing metabolic inflammation, insulin resistance and adipose tissue dysfunction. Hyperleptinemia, hyperglycemia and dyslipidemia are also the primary observations of obesogenic diet induced obesity. We have previously reported anti-adipogenic and insulin sensitizing effects of blue mussels (BM) using 3T3-L1 cells. BM is a rich source of omega-3 polyunsaturated fatty acids, phytosterols and other micronutrients that has been shown to elicit benefits under obese conditions using in-vitro cell culture models. However, no studies to date have established the anti-obesity effects, safety and efficacy of BM in an in-vivo animal model. In the present study, we fed a HF-HS diet supplemented with different concentrations of BM freeze-dried powder (1.25, 2.5 and 5% w/w) to C57BL/6 mice for 12weeks. A HF-HS diet caused rapid weight gain, hyperglycemia, dyslipidemia, hyperleptinemia, and increased plasma levels of inflammatory cytokines; interleukin (IL)-6 and tumor necrosis factor (TNF)-α. Incorporating 2.5% BM in the HF-HS diet prevented weight gain, dyslipidemia, hyperglycemia and reduced the levels of inflammatory cytokines and leptin mRNA expression. Furthermore, plasma from 2.5% BM increased cholesterol efflux capacity of J774 macrophage cells, compared to plasma from HF-HS diet. There was no effect of 1.25% BM on any tested parameters, while 5% BM was not palatable after four weeks. In conclusion, our findings have established the efficacy and safety of BM using C57BL/6 mice, demonstrating that BM has the potential to target obesity and related complications.

Dietary Omega-3 Fatty Acids Prevented Adipocyte Hypertrophy by Downregulating DGAT-2 and FABP-4 in a Sex-Dependent Fashion.

Obesity is characterized by an increase in fat mass primarily as a result of adipocyte hypertrophy. Diets enriched in omega (n)-3 polyunsaturated fatty acids (PUFA) are suggested to reduce obesity, however, the mechanisms are not well understood. We investigated the effect of n-3 PUFA on adipocyte hypertrophy and the key genes involved in adipocyte hypertrophy. Female C57BL/6 mice were fed semi-purified diets (20 % w/w fat) containing high n-3 PUFA before mating, during pregnancy, and until weaning. Male and female offspring were continued on high n-3 PUFA (10 % w/w), medium n-3 PUFA (4 % w/w), or low n-3 PUFA (2 % w/w) diet for 16 weeks postweaning. Adipocyte area was quantified using microscopy, and gonadal mRNA expression of acyl CoA:diacylglycerol acyltransferase-2 (DGAT-2), fatty acid binding protein-4 (FABP-4) and leptin were measured. The high n-3 PUFA group showed higher levels of total n-3 PUFA in gonadal TAG compared to the medium and low n-3 PUFA groups (P < 0.001). The high n-3 PUFA male group had a lower adipocyte area compared to the medium and low n-3 PUFA group (P < 0.001); however, no difference was observed in females. The high n-3 PUFA male group showed lower mRNA expression of FABP-4, DGAT-2 and leptin compared to the low n-3 PUFA group, with no difference in females. Plasma lipid levels were lower in the high n-3 PUFA group compared to the other groups. Our findings show for the first time that n-3 PUFA prevents adipocyte hypertrophy by downregulating FABP-4, DGAT-2 and leptin; the effects are however sex-specific.

Glycogen phosphorylase-a is a common target for anti-diabetic effect of iridoid and secoiridoid glycosides.

PURPOSE: Diabetes mellitus is characterized by hyperglycemia resulting from defects in insulin secretion, action or both. The use of medicinal plants for the treatment of diabetes mellitus dates back from the Ebers papyrus of about 1550 B.C. One of the major problems with herbal drugs is that the active ingredients are not well defined. It is important to know the active components and their molecular interactions which will help to analyze their therapeutic efficacy and also to standardize the product. There are a number of medicinal plants known for their anti-diabetic effect that possess similarities in their active chemical components, e.g. iridoid and secoiridoid glycosides. METHODS: In this study, we have compared the structure of various iridoid and secoiridoid glycosides to design a novel pharmacophore. We further developed a structure-activity relationship for the inhibition of glycogen phosphorylase-a. CONCLUSION: By using docking studies, we are proposing, for the first time, that inhibition of glycogen phosphorylase-a activity is a common target for iridoids and secoiridoids to elicit anti-diabetic effects. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

Fish oil induced hyperlipidemia and oxidative stress in BioF1B hamsters is attenuated by elderberry extract.

We have previously reported fish oil induced hyperlipidemia in BioF1B hamsters compared with Golden Syrian (GS) hamsters. Elderberry (Sambucus nigra L.) extract is abundant in anthocyanins and is believed to exert cardioprotective effects primarily by virtue of its hypolipidemic and antioxidant potential. In the current study, high-fat fish oil feeding increased oxidative stress in BioF1B hamsters compared with GS hamsters; this increase was associated with increased levels of omega-3 polyunsaturated fatty acids in plasma and liver. We then investigated whether cosupplementation with anthocyanin-rich elderberry extract would reverse fish oil induced hyperlipidemia and reduce lipid peroxidation in BioF1B hamsters. Plasma and hepatic lipids decreased significantly when hamsters were fed diets containing elderberry extract along with fish oil. Both plasma and liver thiobarbituric acid reactive substances showed significant reductions upon cosupplementation with elderberry extract in fish oil fed BioF1B hamsters. Our findings demonstrate that cosupplementation with elderberry extract reverses hyperlipidemia and lipid peroxidation observed with dietary fish oil alone in BioF1B hamsters.

Maternal dietary fat intake during gestation and lactation alters tissue fatty acid composition in the adult offspring of C57Bl/6 mice.

We investigated the effects of maternal dietary fat intake during gestation and lactation on the tissue fatty acid composition of the adult offspring. Female C57Bl/6 mice were fed high fat diets enriched with lard or safflower oil or chow during mating, gestation and lactation. The offspring obtained from each group of mothers were continued on diets rich in lard, safflower oil or chow post-weaning until 11 weeks of age. Livers and hearts were collected for fatty acid analysis. A maternal diet rich in safflower oil was associated with enrichment of hepatic tissue with n-3 polyunsaturated fatty acids in the offspring fed chow post-weaning compared to the offspring fed chow throughout. However, a continuous exposure to a safflower oil- as well as lard-rich diet during the pre- and post-weaning time periods was associated with reduced content of docosahexaenoic acid in both liver and heart tissues compared to the offspring fed chow throughout. In conclusion, this study demonstrated lasting effects of maternal dietary fat intake, as well as an interaction between pre- and post-weaning diets, on the tissue fatty composition in adult offspring.