Treatment of preadipocytes with fish oil, mixed oil, or soybean oil-based lipid emulsions have differential effects on the regulation of lipogenic and lipolytic genes in mature 3T3-L1 adipocytes.

The key adipose tissue characteristics are established during early development, where lipids play an essential role. Lipid emulsions used in total parenteral nutrition have different omega-(n) 6 to n-3 fatty acid ratios. A lower n-6:n-3 fatty acid decreases lipid accumulation; however, the effects of lipid emulsions with different n-6 to n-3 fatty acid ratios on the programming of preadipocytes to affect lipid accumulation in mature adipocytes is not known. This study compared the effects of Fish oil (FO), Mixed oil (MO), and Soybean oil (SO) based lipid emulsion on genes involved in adipogenesis, lipogenesis, lipolysis, and ß-oxidation in 3T3-L1 adipocytes. Preadipocytes were treated with specific lipid emulsions and then differentiated to mature adipocytes in the absence of lipid emulsions. In a separate experiment, mature 3T3-L1 adipocytes were treated with lipid emulsions to investigate the effects on genes involved in lipolysis. Fatty acid composition, triacylglycerol levels, and the mRNA expression of genes involved in adipogenesis, lipogenesis, lipolysis, and ß-oxidation were measured. Preadipocytes and mature adipocytes treated with FO showed higher incorporation of n-3 polyunsaturated fatty acids, lower triacylglycerol levels, and decreased mRNA expression of adipogenic and lipogenic genes, followed by MO and SO. FO and MO increased the mRNA expression of carnitine palmitoyltransferase-1, while FO decreased the mRNA expression of lipolytic genes compared to untreated cells. Our findings suggest that FO programs preadipocytes to prevent adipose tissue dysfunction in mature adipocytes; the effects of FO-based lipid emulsion were followed by MO and SO.

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.

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.

Anti-diabetic activity of swertiamarin is due to an active metabolite, gentianine, that upregulates PPAR-γ gene expression in 3T3-L1 cells.

We have previously shown the anti-diabetic effects of swertiamarin; however, pharmacokinetic analysis showed that swertiamarin had a plasma half-life of 1.3 h. Gentianine is an active metabolite of swertiamarin that possesses a pharmacophoric moiety. The aim of this study was to explore the possibility whether the anti-diabetic effect of swertiamarin is due to gentianine. Swertiamarin treatment had no significant effect on adipogenesis, or the mRNA expression of PPAR-γ and GLUT-4; however, there was a significant increase in the mRNA expression of adiponectin. On the other hand, treatment with gentianine significantly increased adipogenesis, which was associated with a significant increase in the mRNA expression of PPAR-γ, GLUT-4 and adiponectin. These findings suggest, for the first time, that the anti-diabetic effect of swertiamarin is due to gentianine, an active metabolite of swertiamarin.

Beneficial effects of swertiamarin on dyslipidaemia in streptozotocin-induced type 2 diabetic rats.

Dyslipidaemia is one of the major risk factors for cardiovascular disease in diabetes mellitus. Lipid changes associated with diabetes mellitus are attributed to increases in free fatty acid flux, secondary to insulin resistance. In the present study, we have investigated the beneficial effects of swertiamarin on dyslipidaemic conditions associated with type 2 diabetes in streptozotocin-induced type 2 diabetic rats. Swertiamarin (50 mg/kg, i.p.) administered once a day for 6 weeks resulted in significant (p < 0.001) reductions in serum triglycerides, cholesterol and low-density lipoprotein levels in diabetic animals as compared with diabetic control animals. Serum fasting glucose was significantly (p < 0.05) decreased, moreover, the insulin sensitivity index was significantly (p < 0.05) increased in swertiamarin treated animals. Overall the data suggest that swertiamarin has beneficial effects on diabetic associated complications such as dyslipidaemia.

Antihyperlipidaemic activity of swertiamarin, a secoiridoid glycoside in poloxamer-407-induced hyperlipidaemic rats.

We have investigated antihyperlipidaemic effect of swertiamarin (50 mg/kg, oral once) isolated from the perennial herb Enicostemma littorale Blume in poloxamer 407 (P-407)-induced hyperlipidaemic rats. Rats were made hyperlipidaemic by intraperitoneal administration of P-407 (400 mg/kg). Serum lipid levels such as total cholesterol, triglycerides and low-density lipoprotein cholesterol increased significantly (P < 0.001) compared with normal control rats. All these changes were significantly prevented in the rats treated with swertiamarin. Serum high-density lipoprotein (HDL) cholesterol was found to be reduced in the P-407 control rats. However, administration of swertiamarin significantly (P < 0.01) increased HDL levels and it showed a significant lipid-lowering effect, as well as a high antiatherogenic potential. Overall swertiamarin is an effective lipid-lowering lead compound and can be useful for preventing atherosclerosis.