Fish oil prevents excessive accumulation of subcutaneous fat caused by an adverse effect of pioglitazone treatment and positively changes adipocytes in KK mice

Docosapentaenoic acid-rich oil lowers plasma glucose and lipids in a mouse model of diabetes and mild obesity

Many studies have investigated the beneficial effects of n-3 polyunsaturated fatty acids, such as their potential for lowering lipid levels and reducing diabetes risk. However, few studies have specifically examined docosapentaenoic acid (DPA), an n-3 polyunsaturated fatty acid with limited availability in its pure form. We hypothesized that DPA would have lipid-lowering effects and improve insulin resistance in KK/Ta mice. To test our hypothesis, 7-week-old KK/Ta mice were fed a high-fat diet for 12 weeks to induce obesity before being divided into 3 groups and fed an experimental diet for 10 weeks. The experimental diets were: LSO, using lard and safflower oil as fat sources; SO, in which lard in the LSO diet was replaced with safflower oil; and DPA, in which lard in the LSO diet was replaced with DPA oil. After 10 weeks, plasma triglyceride and total cholesterol concentrations were significantly decreased in the DPA group, but not in the SO group. Sterol regulatory element-binding protein-1 and stearoyl-CoA desaturase-1 gene expressions involved in fatty acid synthesis in the liver were significantly lower in the DPA group compared with the LSO group. Plasma glucose concentrations were significantly decreased in both the SO group and the DPA group compared with the LSO group, whereas plasma insulin concentrations were significantly decreased in the DPA group alone. These results indicate that DPA has plasma lipid-lowering and hypoglycemic effects, possibly from suppression of fatty acid synthesis in the liver.

Omega-3 fatty acid-based self-microemulsifying drug delivery system (SMEDDS) of pioglitazone: Optimization, in vitro and in vivo studies

Pioglitazone (PGL) is an effective insulin sensitizer, however, side effects such as accumulation of subcutaneous fat, edema, and weight gain as well as poor oral bioavailability limit its therapeutic potential for oral delivery. Recent studies have shown that combination of both, PGL and fish oil significantly reduce fasting plasma glucose, improve insulin resistance, and mitigate pioglitazone-induced subcutaneous fat accumulation and weight gain. Nevertheless, developing an effective oral drug delivery system for administration of both medications have not been explored yet. Thus, this study aimed to develop a self-micro emulsifying drug delivery system (SMEDDS) for the simultaneous oral administration of PGL and fish oil. SMEDDS was developed using concentrated fish oil,Tween® 80, and Transcutol HP and optimized by central composite design (CCD). The reconstituted, optimized PGL-SMEDDS exhibited a globule size of 142 nm, a PDI of 0.232, and a zeta potential of -20.9 mV. The in-vitro drug release study of the PGL-SMEDDS showed a first-order model kinetic release and demonstrated remarkable 15-fold enhancement compared to PGL suspension. Additionally, following oral administration in fasting albino Wistar rats, PGL-SMEDDS exhibited 3.4-fold and 1.4-fold enhancements in the AUC0-24h compared to PGL suspension and PGL marketed product. The accelerated stability testing showed that the optimized SMEDDS formulation was stable over a three-month storage period. Taken together, our findings demonstrate that the developed fish oil-based SMEDDS for PGL could serve as effective nanoplatforms for the oral delivery of PGL, warranting future studies to explore its synergistic therapeutic potential in rats.

Long-term dietary DHA intervention prevents telomere attrition and lipid disturbance in telomerase-deficient male mice

PURPOSE

Previous evidence indicated anti-ageing potential of docosahexaenoic acid (DHA), but the underlying mechanism remains unclear. We investigated protective effect of DHA on telomere attrition and lipid disturbance in male mice with premature ageing caused by telomerase deficiency.

METHODS

Wild-type (WT) and fourth-generation telomerase-deficient (G4 Terc^-/-, Terc knockout, KO) male mice (C57BL/6, 2 months old) were fed control diet (WT-C and KO-C groups) or DHA-enriched diet containing 0.80% DHA by weight (WT-DHA and KO-DHA groups) for 10 months. The ageing phenotypes and metabolic level [carbon dioxide emission, oxygen consumption, and respiratory exchange ratio (RER)] were assessed at the end of the experiment. Telomere length in various tissues and the hepatic gene and protein expression for regulating lipid synthesis and lipolysis were measured. Data were tested using one- or two-factor ANOVA.

RESULTS

In KO male mice, DHA prevented weight loss, corrected high RER, and reduced fat loss. Telomere shortening was reduced by 22.3%, 25.5%, and 13.5% in heart, liver, and testes of the KO-DHA group compared with those in the KO-C group. The KO-DHA group exhibited higher gene transcription involved in glycerol-3-phosphate pathway [glycerol-3-phosphate acyltransferase (Gpat)], lower gene expression of β-oxidation [carnitine palmitoyltransferase 1a (Cpt1a)], and upregulation of proteins in lipid synthesis [mammalian target of rapamycin complex 1 (mTORC1) and sterol responsive element binding protein 1 (SREBP1)] in liver than the KO-C group.

CONCLUSION

Long-term DHA intervention attenuates telomere attrition and promotes lipid synthesis via the tuberous sclerosis complex 2 (TSC2)-mTORC1-SREBP1 pathway in KO male mice.

Dietary n-3 and n-6 polyunsaturated fatty acids differentially modulate the adiponectin and leptinmediated major signaling pathways in visceral and subcutaneous white adipose tissue in high fat diet induced obesity in Wistar rats

Obesity is a chronic metabolic disease that involves excessive accumulation of fat in white adipose tissue (WAT). Apart from storing excess fats, WAT also serves as an important endocrine organ secreting adipocytokines such as adiponectin and leptin. Adiponectin and leptin bind to their transmembrane receptors adiponectin receptor 1 (AdipoR1)/adiponectin receptor 2 (AdipoR2) and Ob-R, respectively, and mediate their effect on metabolism by regulating multiple downstream targets. Dietary fat is considered the main culprit behind obesity development. Numerous preclinical studies have highlighted role of essential polyunsaturated fatty acids (PUFAs), particularly n-3 PUFAs, in prevention of obesity. Despite emerging data, there still is no clear understanding of the mechanism of action of n-3 PUFAs and n-6 PUFAs on adipose tissue function in two functionally and anatomically different depots of WAT: visceral and subcutaneous. We designed this study using a high fat diet (HFD) fed rodent model of obesity to test our hypothesis that n-3 and n-6 PUFAs possibly differentially modulate adipokine secretion and downstream metabolic pathways such as peroxisome proliferator-activated receptor-γ (PPAR-γ), protein kinase B (AKT)-forkhead box O1 (FOXO1), and Janus kinase-signal transducer and activator of transcription in obesity. The results of the current study showed that n-3 PUFAs upregulate the expression of AdipoR1/R2 and ameliorate the effects of HFD by modulating adipogenesis via PPAR-γ and by improving glucose tolerance and lipid metabolism via AKT-FOXO1 axis in fish oil fed rats. However, n-6 PUFAs did not show any remarkable change compared with HFD fed animals. Our study highlights that n-3 PUFAs modulate expression of various targets in adiponectin and leptin signaling cascade, bringing about an overall reduction in obesity and improvement in adipose tissue function in HFD induced obesity.

Sardine oil loaded vanillic acid grafted chitosan microparticles improves the in vivo antioxidant, haematological and lipid profile

Oxidative stability of fish oil supplements poses a considerable health risk which can be prevented by novel delivery systems. A newly developed formulation of microencapsulated sardine oil showed excellent oxidative stability in vitro. The present study's objective is to evaluate the new formulation in vivo as a potential new supplement which may improve antioxidant, haematological, and lipid profile. The optimisation of the sardine oil loaded microparticles (SO-M) and the characterisation have been presented briefly. The SO-M formulation was fed to male albino rats for two months. Following the feeding experiment, haemoglobin content, platelet and RBC count were assessed in the control and treated group. Similarly, levels of serum cholesterol, HDL, LDL, triglycerides, and metabolic enzyme biomarkers, namely catalase, SOD, GST, AST, ALT, ACP and ALP, were compared. The blood analysis showed a significant increase in haemoglobin, platelets and RBC count in the treated group. Lipid profiling showed that both triglycerides and LDL levels were decreased in the sample treated group. This study also showed significant modulation of antioxidant enzymes such as catalase, SOD and GST. The new formulation of PUFA rich sardine oil significantly improved the in vivo antioxidant, haematological and lipid profile, suggesting potential use as a dietary supplement.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-021-05329-5.

Renal Cell Cancer and Obesity

Cancers are a frequent cause of morbidity and mortality. There are many risk factors for tumours, including advanced age, personal or family history of cancer, some types of viral infections, exposure to radiation and some chemicals, smoking and alcohol consumption, as well as obesity. Increasing evidence suggest the role of obesity in the initiation and progression of various cancers, including renal cell carcinoma. Since tumours require energy for their uncontrollable growth, it appears plausible that their initiation and development is associated with the dysregulation of cells metabolism. Thus, any state characterised by an intake of excessive energy and nutrients may favour the development of various cancers. There are many factors that promote the development of renal cell carcinoma, including hypoxia, inflammation, insulin resistance, excessive adipose tissue and adipokines and others. There are also many obesity-related alterations in genes expression, including DNA methylation, single nucleotide polymorphisms, histone modification and miRNAs that can promote renal carcinogenesis. This review focuses on the impact of obesity on the risk of renal cancers development, their aggressiveness and patients’ survival.

Dietary ω-3 fatty acids and their influence on inflammation via Toll-like receptor pathways

Dietary intake of long-chain, highly unsaturated ω-3 fatty acids (FAs) is considered indispensable for humans. The ω-3 FAs have been known to be anti-inflammatory and immunomodulatory dietary factors; however, the modes of action on pathogen recognition receptors (PRRs) and downstream signaling pathways have not been fully elucidated. Dietary sources contain various amounts of ω-3 long-chain fatty acids (LCFAs) of different lengths and the association between intake of these polyunsaturated fatty acids (PUFAs) with underlying mechanisms of various immune-related disorders can be of great interest. The potential anti-inflammatory role for ω-3 LCFAs can be explained by modification of lipid rafts, modulation of inflammatory mediators such as cytokines and PRRs. Toll-like receptors (TLRs) are a group of PRRs that play an important role in the recognition of bacterial infections and ω-3 FAs have been implicated in the modulation of downstream signaling of TLR-4, an important receptor for recognition of gram-negative bacteria. The ω-3 FAs docosahexaenoic acid and eicosapentaenoic acid have been investigated in vivo and in vitro for their effects on the nuclear factor-κB activation pathway. Identification of the effects of ω-3 FAs on other key molecular factors like prostaglandins and leukotrienes and their signals may help the recognition and development of medicines to suppress the main mediators and turn on the expression of anti-inflammatory cytokines and nuclear receptors.

Ameliorative effect of combined low dose of Pioglitazone and omega-3 on spermatogenesis and steroidogenesis in diabetic rats

BACKGROUND

Chronic hyperglycemia is linked to either subfertility or infertility among diabetic males. Pioglitazone is one of the thiazolidinediones (TZDs) drugs that are selective peroxisome proliferator-activated receptor (PPAR-γ agonists used for treating type 2 diabetes mellitus (T2DM).

AIM

This study aims to explore the possible effect of low Pioglitazone dose and omega (ω-3) on rat male reproductive function. Furthermore, we evaluated the add-on effect of combined use of low Pioglitazone dose of and ω-3 on reproductive functions in adult male T2DM rats.

METHODS

Fifty adult male rats were included and subdivided into control and four test subgroups. T2DM was induced in test groups and subdivided into non-treated T2DM, ω-3 treated, 0.6 mg/kg Pioglitazone treated, and combined treated group (orally by gavage). Following 16 weeks, final body weight, testicular weight, fasting plasma glucose, and serum testosterone levels were measured. Semen analysis, testicular testosterone, malondialdehyde (MDA) concentrations, superoxide dismutase (SOD) activity, immunohistochemistry staining for apoptosis marker B-cell lymphoma protein 2 (Bcl-2), proliferation marker as proliferating cell nuclear antigen (PCNA), estrogen receptor α (ERα), androgen receptor (AR) were determined. Caspase-3, nuclear factor-kappa B (NF-kB), glucose transporter 3 (GLUT3), 17β-hydroxysteroid dehydrogenases (17β-HSD) PPARγ, and PPARα genes expression were analyzed by real-time polymerase chain reaction (RT-PCR).

RESULTS

Our findings revealed that treatment with low dose of Pioglitazone or ω-3 significantly lowered fasting plasma glucose and MDA levels, ameliorated diabetes effects on histological damage, improved antioxidant activity (SOD), significantly improved anti-apoptosis BCL-2 and proliferation (PCNA), remarkably elevated ERα, AR, 17β-HSD PPARγ, and PPARα expression with significant reduction in caspase-3, NF-kB genes expression and improved semen quality as well. Combined use of low dose of and ω-3 has better effects on all measured parameters.

CONCLUSION

Small Pioglitazone dose and ω-3 possess beneficial effects on spermatogenic and steroidogenic functions in adult diabetic rat; while combined use of both has an add-on effect.

Pre-germinated brown rice extract ameliorates high-fat diet-induced metabolic syndrome

This study examined the effect of pre-germinated brown rice extract (PGBRE), containing no dietary fibers, but γ-oryzanol, γ-aminobutyric acid (GABA), flavonoids, and anthocyanidin, on high-fat-diet (HFD)-induced metabolic syndrome. C57BL/6 mice were divided into five groups: regular diet, HFD, HFD with oral PGBRE 30, 300, or 600 mg/kg per day for 18 weeks. In the HFD group, higher body and liver weight gain, hyperglycemia, HbA1c, and insulin; higher TG, TC, LDL-C, non-HDL, atherosclerosis index, lower HDL, adiponectin in blood; higher TG in the liver; higher TG, bile acid in feces; and lower protein levels of AMP-activated protein kinase, insulin receptor, insulin receptor substrate-1, insulin receptor substrate-2, peroxisome proliferator-activated receptor-γ, phosphatidylinositol-3-kinase, Akt/PKB, glucose transporter-1, glucose transporter-4, glucokinase in the skeletal muscle; lower glucagon-like peptide 1 (GLP-1) in the intestine; higher sterol regulatory element-binding protein-1 (SREBP-1), stearoyl-CoA desaturase 1 (SCD-1), fatty acid synthase (FAS), 3-hydroxy-3-methylglutaryl-CoA reductase, proprotein convertase subtilisin/kexin type 9 (PCSK9), and lower PPAR-α, low-density lipoprotein receptor, cholesterol-7α-hydroxylase in the liver; higher SREBP-1, SCD-1, FAS, and lower PPAR-α, adiponectin in the adipose tissue were found. In HFD + PGBRE groups, the above biochemical parameters were improved. PRACTICAL APPLICATIONS: According to the results, we suggested that dietary fibers played a minor role in this study. Extract of PGBR, excluding dietary fiber, showed beneficial activity to ameliorate metabolic syndrome. γ-oryzanol, GABA, flavonoids, and anthocyanidin in PGBRE can inhibit HFD-induced metabolic syndrome and we demonstrated clearly its action mechanisms. This is the first report to examine the relation between PGBRE, GLP-1, and PCSK9. Taken together, PGBRE can potentially be used to develop a good supplement to control metabolic syndrome.

Anthocyanins from Cornus kousa ethanolic extract attenuate obesity in association with anti-angiogenic activities in 3T3-L1 cells by down-regulating adipogeneses and lipogenesis

Cornus kousa the Korean dogwood has been traditionally used in East Asia as therapeutic traditional medicine however biological activities of Cornus kousa have not been investigated previously. The aim of the present study was to evaluate anti-obesity activities coupled with anti-angiogenic activities of anthocyanins rich fraction of ethanolic leaf extract of Cornus kousa (ELECk) in HUVECs and 3T3- L1 cells. Dried plants leaves were extracted with 70% ethanol and anthocyanin fraction (AnT Fr) was obtained by eluting the ethanolic extract through non-polar macroporous resin and further purification by HPLC. Antiangiogenic activities were determined by antiproliferative effect of AnT Fr on HUVECs. In the presence of various concentrations of AnT Fr, 3T3-L1 preadipocytes were induced to differentiate. Lipid accumulation in differentiated adipocytes were quantified by Oil-Red O staining. AnT Fr significantly suppressed angiogenesis by inhibiting proliferation and tube formation of HUVECs via downregulating VEGRF 2, PI3K, β-catenin, NF-kB, and Akt1 in a dose dependent manner. AnT Fr inhibited lipid accumulation by down-regulating adipogenesis and lipogenesis promoting signaling proteins, PPARγ, CCAAT, C/EBPα, aP2, FAS, and LPL, however enhanced AMPK activation to p-AMPK in 3T3 cells quantified and expressed by western blotting. AnT Fr inhibit lipid accumulation by regulating adipogenesis and lipogenesis related genes and signaling proteins. The anti-obesity activities exerted by Cornus kousa are associated with antiangiogenic activities of anthocyanins rich fraction of Cornus kousa. Hence the presence of bioactive anthocyanins, Cornus kosa, is a good candidate for nutraceutical and pharmaceutical formulation for treating or controlling obesity.

Perilla Oil Supplementation Improves Hypertriglyceridemia and Gut Dysbiosis in Diabetic KKAy Mice

SCOPE

The aim of this study is to examine whether perilla oil supplementation improves glucolipid metabolism and modulates gut microbiota in diabetic KKAy mice.

METHODS AND RESULTS

The successfully established diabetic KKAy mice are randomized into four groups: diabetic model (DM), low-dose perilla oil (LPO), middle-dose perilla oil (MPO), and high-dose perilla oil (HPO). C57BL/6J mice are fed a chow diet as normal control (NC). At the end of 12 weeks, mice are euthanized and glucolipid indications are analyzed. Gut microbiota analysis is carried out based on the sequencing results on V4 region of 16S rRNA. Although serum glucose, insulin, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, abundance-based coverage estimator, and shannon are unchanged, serum triglyceride significantly decreases in LPO compared with DM. The histopathological changes of hepatocellular macrovesicular steatosis and adipocyte hypertrophy are ameliorated by perilla oil supplementation. Blautia is significantly decreased in LPO, MPO, and HPO, compared with DM. Nonmetric multidimensional scaling analysis shows NC and LPO are relatively coherent.

CONCLUSION

These findings indicate that dietary supplementation with perilla oil can improve hypertriglyceridemia and gut dysbiosis in diabetic KKAy mice, which can be associated with potential benefits to human health.

Benefits of combination low-dose pioglitazone plus fish oil on aged type 2 diabetes mice

The elderly patients with type 2 diabetes suffer more adverse drug events than young adults due to pharmacokinetic and pharmacodynamic changes associated with aging. Reducing the risks of these medication-related problems are equally important for the clinical care of older type 2 diabetes patients. Pioglitazone is used for treating type 2 diabetes as an oral antidiabetic drug. Despite pioglitazone is used helpful insulin sensitizers, the accumulation of subcutaneous fat is considered a major adverse effect of pioglitazone therapy. We investigated to reduce the adverse effect of pioglitazone by combination with fish oil rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in aged diabetic KK mice. The accumulation of subcutaneous fat associated with high-dose pioglitazone is reduced by fish oil, suppressing lipogenesis and stimulating fatty acid β-oxidation in the liver. Our data suggest that adding fish oil to low-dose pioglitazone results in anti-diabetic efficacy similar to that of the high-dose without concomitant body weight gain.

Modulation of the gut microbiota by the mixture of fish oil and krill oil in high-fat diet-induced obesity mice

Previous studies confirmed that dietary supplements of fish oil and krill oil can alleviate obesity in mice, but the underlying mechanism remains unclear. This study aims to discern whether oil treatment change the structure of the gut microbiota during the obesity alleviation. The ICR mice received high-fat diet (HFD) continuously for 12 weeks after two weeks of acclimatization with a standard chow diet, and the mice fed with a standard chow diet were used as the control. In the groups that received HFD with oil supplementation, the weight gains were attenuated and the liver index, total cholesterol, triglyceride and low-density lipoprotein cholesterol were reduced stepwise compared with the HFD group, and the overall structure of the gut microbiota, which was modulated in the HFD group, was shifted toward the structure found in the control group. Moreover, eighty-two altered operational taxonomic units responsive to oil treatment were identified and nineteen of them differing in one or more parameters associated with obesity. In conclusion, this study confirmed the effect of oil treatment on obesity alleviation, as well as on the microbiota structure alterations. We proposed that further researches are needed to elucidate the causal relationship between obesity alleviation and gut microbiota modulation.

Protective effects of fish oil and pioglitazone on pancreatic tissue in obese KK mice with type 2 diabetes

n-3 Polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have protective effects against the pancreatic β-cell dysfunction through several mechanisms. Thiazolidines are insulin sensitizers and are used in treating patients with type 2 diabetes. Our previous study demonstrated that a combination of fish oil, which is rich with EPA and DHA, and pioglitazone exerts beneficial effects on obesity and diabetes through their actions on the liver and adipose tissue. However, it remains largely unknown whether such combination therapy affects the pancreas. To answer this question, KK mice, which serve as a model for obesity and type 2 diabetes, were treated for 8 weeks with fish oil and pioglitazone. The combined regimen suppressed pancreatic islet hypertrophy (mean islet area decreased by an average of 49% vs. control) compared with mice treated with fish oil or pioglitazone alone (decreased by an average of 21% and 32% vs. control, respectively). Compared with the controls, individual or combined treatment significantly increased the percentage of β-cell area in the pancreatic islets, significantly decreased endoplasmic reticulum stress, and reduced the percentage of apoptotic cell death in the pancreatic islets. These findings suggest that fish oil and/or pioglitazone prevents β-cell dysfunction by improving the insulin resistance and decreasing the ER stress.