Effects of dietary fish oil and trans fat on rat aorta histopathology and cardiovascular risk markers

Safety assessment of fish oil green extraction and in vivo acute toxicity evaluation

Sardine co-products can represent an interesting source of bioactive compounds, such as polyunsaturated fatty acids and in particular omega-3. This study aimed to investigate extraction of oil from sardine co-products by enzymatic hydrolysis using two proteases: commercial Alcalase and protease Bb from a local fungal strain (P2) of Beauveria bassiana, which overproduces proteases. Despite a higher degree of hydrolysis (41.34%) than Alcalase (24.28%), protease Bb allowed the extraction of approximately the same oil content. Resulting oil from both processes had the same fatty acid profile. Interestingly, the all-produced oil displayed an attractive w6/w3 ratio, an indicator of nutritional quality, of the order of 0.16. The safety of the generated oils was also assessed by treating two groups of Wistar rats with the fish oil administered by oral gavage at the doses (30 mg/kg and 300 mg/kg body weight) for 14 days using olive oil as a vehicle. Compared to controls used, both treated groups showed no statistically significant differences. Consequently, the acute oral toxicity evaluated by hematological, biochemical, and histological studies showed the safety of the oil generated using B. bassiana protease.

Role of anti-inflammatory interventions in high-fat-diet-induced obesity

Lipotoxicity is defined as deposition of excess fat associated with an inflammatory response. Metabolomic analysis of fatty acids (FAs) can be a marker of silent inflammation. ω3-Enriched diet, celecoxib, and safranal may have a protective anti-inflammatory role. In this work, total FAs extracted from red blood cells and arachidonic acid-to-eicosapentaenoic acid (AA-to-EPA) ratios were assessed using GC-MS assay in single-ion monitoring mode. The study was conducted on 64 male rats divided into eight groups: I, controls; II, rats received high-fat diet (HFD), III, rats received ω-6-enriched HFD; IV, rats received ω-3-enriched HFD; V, rats received celecoxib with HFD; VI, rats received safranal with HFD; VII and VIII, rats received celecoxib and safranal with ω-3 HFD, respectively. GC-MS Gas chromatography Mass spectrometry was performed for analysis of fatty acid methyl ester. Enzyme-linked immunosorbent assay was used to analyze serum interleukin-6 (IL-6) and transforming growth factor-beta 1 (TGF-β1) concentrations. A statistically significant decrease of AA-to-EPA ratio was observed in group VII when compared with the groups receiving HFDs. This group also showed the lowest serum IL-6 level and highest TGF-β1 level. In conclusion, ω3-enriched diet along with drugs (e.g. celecoxib) and herbal medications (e.g. safranal) may have an anti-inflammatory effect in lipotoxicity. GC-MS with single-ion monitoring is valid for the analysis of FAs.

Intrauterine hyperglycemia-induced inflammatory signalling via the receptor for advanced glycation end products in the cardiac muscle of the infants of diabetic mother rats

PURPOSE

Gestational diabetes is associated with increased risk to the health of the mother and her offspring. In particular, the infants of diabetic mothers (IDMs) exhibit elevated levels of preterm birth, macrosomia, hypoglycemia, hypocalcemia, and cardiomyopathy. We have previously reported that IDMs showed abnormalities in cardiac Akt-related insulin signalling, and that these deficiencies in Akt-related signalling were attenuated by supplementing the maternal diet with fish-oil. Herein, we investigated whether the eicosapentaenoic acid (EPA) found in fish oil can be used to attenuate diabetes associated impairments in cardiomyocyte signalling.

METHODS

Pregnant diabetic rats were administered streptozotocin before receiving EPA or water, and their infants were designated IDM/EPA, IDM/W. We assessed the potential molecular pathway for this effect in the primary cardiac cell from newborn rat hearts.

RESULTS

Insulin resistance as determined by diminished GLUT4 translocation following insulin stimulation, the levels of advanced glycation end products (AGEs) and reactive oxygen species were elevated in the neonatal hearts of IDM/W compared with that seen in the offspring born from non-diabetic control animals. Similarly, the receptor of AGEs (RAGE) mRNA levels, reactive oxygen species and the amount of nuclear factor-κB (NF-κB), tumor necrosis factor-α (TNF-α), and interleukin 6 (IL-6) mRNA were higher in the hearts from the IDM/W when compared to that observed in the hearts of offspring born to non-diabetic animals. These deleterious effects of gestational diabetes were significantly decreased in the offspring of diabetic mothers receiving EPA supplementation.

CONCLUSIONS

Taken together, our data suggest that the EPA in fish oil may improve the impaired signalling and the excessive protein glycation in the cardiac muscles of infants exposed to intrauterine hyperglycemia.

Effect of Omega-3 Supplementation on Visfatin, Adiponectin, and Anthropometric Indices in Women with Polycystic Ovarian Syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is a multifactorial, metabolic disorder. Characteristics are chronic anovulation, polycystic ovaries and hyperandrogenism. The aim of this study was to determine the effect of omega-3 supplementation on visfatin, adiponectin, and anthropometric indices in PCOS women.

METHODS

The study was a randomized double blind placebo-controlled clinical trial. It was conducted on 84 women with polycystic ovary syndrome (26.92±5.05 years, BMI=31.69 Kg/m (2)) who referred to the fertility and infertility research center and Shahid Sadoughi hospital in Yazd. After the examination, evaluation and para-medical assessment by obstetrician, they were recruited. They took 3 capsules of omega-3 (each one contained 180 mg EPA and 120 mg DHA) or placebo (each contained 1 g paraffin) daily for 8 weeks. Statistical analysis was paired T-test and student T-test, and a p<0.05 was considered statistically significant.

RESULTS

After the intervention, visfatin concentration did not change in neither groups. But, at the end of the study, the mean of adiponectin concentration increased (p<0.001) in omega-3 group. Moreover, the mean of changes in this factor was significantly different between groups (p<0.005). FSH did not change in two groups of the study. However, the mean of LH decreased about 1.74 mlU/ml in omega-3 group (p<0.005). The mean of change of LH/FSH ratio between groups was significant (p<0.05). After the intervention, prolactin did not meaningfully change in both groups.

CONCLUSION

Our results showed that 8 weeks of supplementation of omega-3 may have some beneficial effects on PCOS biochemical characteristics such as LH, LH/FSH, and adiponectin.

Cholesterol-cholate-butterfat diet offers multi-organ dysfunction in rats

Background

Comparable to commercial expensive high-fat diets, cholesterol-cholate-butterfat (CCB) diet has also been used to induce hyperlipidemia in rats. Our objective was to explore its influence on multiple organs. Consequence of fasting was also analysed.

Methods

Rats in groups 1 and 2 received normal diet (ND) whereas groups 3 and 4 received CCB-diet. Food was withdrawn daily for two hours from groups 2 (ND-F) and 4 (CCB-F). Blood was collected at fourth and sixth week for biochemical estimation; Morris water maze was done in the sixth week for learning ability and memory; after which aortae were isolated for vascular reactivity.

Results

Apart from hyperlipidemia, CCB also induced hyperglycemia with marked increase in hepatic enzymes: gamma-glutamyl transferase (GGT), alanine and aspartate aminotransferase (ALT and AST); and vascular biomarkers: uric acid (UA), phosphorus and alkaline phosphatase (ALP). Isolated aortae, pre-contracted with phenylephrine, were less responsive to acetylcholine indicating endothelial dysfunction – serum nitric oxide (NO) production was limited with subsequent inhibition of endothelial NO synthase. CCB diet also compromised learning ability. CCB-coupled fasting potentiated hyperlipidemia but prevented memory-loss.

Conclusion

We introduce CCB-diet for multi-organ dysfunction in rats, and propose its use for research on cardiovascular diseases and associated manifestations involving immense interplay of integrated pathways.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-511X-13-194) contains supplementary material, which is available to authorized users.

Eicosapentaenoic acid/docosahexaenoic acid 1:1 ratio improves histological alterations in obese rats with metabolic syndrome

Background

Marine polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been associated with improvement in the Metabolic Syndrome (MS). The aim of this study is to evaluate how three fish-oil diets with different eicosapentaenoic acid/docosahexaenoic acid ratios (EPA/DHA ratio) affect the histology of liver, kidney, adipose tissue and aorta in a preliminary morphological study. This work uses an animal model of metabolic syndrome in comparison with healthy animals in order to provide information about the best EPA:DHA ratio to prevent or to improve metabolic syndrome symptoms.

Methods

35 Wistar rats, as a control, and 35 spontaneously hypertensive obese rats (SHROB) were fed for 13 weeks with 3 different suplemmentation of fish oil containing EPA and DHA ratios (1:1, 2:1 and 1:2, respectively). All samples were stained with haematoxylin/eosin stain, except aorta samples, which were stained also with Verhoeff and van Gieson’s stain. A histological study was carried out to evaluate changes. These changes were statistically analyzed using SPSS IBM 19 software. The quantitative data were expressed by mean ± SD and were compared among groups and treatments using ANOVA with post-hoc tests for parametric data and the U-Mann–Whitney for non-parametric data. Qualitative data were expressed in frequencies, and compared with contingency tables using χ² statistics.

Results

EPA:DHA 1:1 treatment tended to improve the density and the wrinkling of elastic layers in SHROB rats. Only Wistar rats fed with EPA:DHA 1:1 treatment did not show mast cells in adipose tissue and has less kidney atrophy. In both strains EPA:DHA 1:1 treatment improved inflammation related parameters in liver and kidney.

Conclusions

EPA:DHA 1:1 treatment was the most beneficial treatment since improved many histological parameters in both groups of rats.

A maternal diet rich in fish oil may improve cardiac Akt-related signaling in the offspring of diabetic mother rats

OBJECTIVE

Newborns of diabetic mothers have abnormal circulatory organs, so in this study, we explore insulin signaling in the newborn rat heart.

METHODS

Pregnant rats were divided into streptozotocin-induced diabetic groups (DM) and control groups (CM). Rats were fed lard (21% fat), fish oil (21% fat), or a control diet (7% fat). To examine changes in insulin signaling in the hearts of infants of diabetic mothers (IDM) in relation to diet, we isolated the hearts from the IDM and control infants and determined the phosphorylation levels of Akt308, Akt473, p38, c-jun-NH2-terminal protein kinase (JNK), and extracellular signal-regulated protein kinase (ERK), and the expression levels of phosphoinositide-dependent protein kainase1 (PDK1) and mammalian target of rapamycin (mTOR).

RESULTS

The mean blood glucose levels in the DM group and their infants were significantly higher than those in the CM group (P < 0.05) and their infants (P < 0.05), but the mean blood glucose levels of all infants was normal on postnatal d 4. Phosphorylation levels of Akt (Thr 308) (P < 0.05) and Akt (Ser 473) and the expression levels of PDK1 and mTOR were lower in infants of diabetic mothers (IDM) than in control infants. The phosphorylation level of Akt (Ser 473) and the expression level of mTOR increased in IDM fed the fish oil diet compared with those fed the lard diet (P < 0.05).

CONCLUSION

A maternal diet rich in fish oil improves cardiac Akt-related signaling in the offspring of diabetic rats.

Trans fat involvement in cardiovascular disease

Coronary heart disease is becoming a worldwide epidemic and diet and lifestyle are well known contributing factors. Identifying the kinds of foods that may have a cardioprotective or cardiotoxic effect and understanding their molecular mechanisms of action has become of increasing importance. Through largely epidemiological evidence, trans fatty acid (TFA) intake has been associated with a variety of cardiovascular complications including atherosclerosis. Traditionally, industrial TFAs (iTFAs) have been associated with these deleterious cardiovascular effects. However, there is a current body of research that suggests that ruminant trans fats (rTFAs) may have a cardioprotective role within the heart. The molecular mechanisms whereby TFAs are delivering their effects are largely unknown. In the following review, we discuss recent in vitro, animal and epidemiological research to better understand the effect of TFAs in the diet on cardiovascular disease, particularly atherosclerosis.

Dietary fish oil modestly attenuates the effect of age on diastolic function but has no effect on memory or brain inflammation in aged rats

Fish oil (FO) mediates a number of cardioprotective benefits in patients with cardiovascular disease. In the absence of cardiovascular disease, however, the effects of FO on cardiac structure and function are not clear. In addition, it is not known if an effective dosing strategy for attenuating age-related cardiac dysfunction is also effective at limiting cognitive dysfunction. Therefore, we determined if 4 months of FO supplementation in aged rats would lessen age-related cardiac dysfunction while concomitantly preventing the cognitive decline that is normally observed in this population. The results indicate that FO initiated late in life modifies diastolic function in a small but positive way by attenuating the age-related increases in filling pressure, posterior wall thickness, and interstitial collagen without mitigating age-related deficits in memory or increases in brain inflammation. These data raise the possibility that FO supplementation for purposes of cardiac and brain protection may need to occur earlier in the life span.

Fish oil increases atherosclerosis and hepatic steatosis, although decreases serum cholesterol in Wistar rat

BACKGROUND

It is known that fish oil consumption decreases incidence of cardiovascular disease. However, some studies showed that it increases atherosclerosis as it does not get completely metabolized by the liver. The aim of the present study was to investigate the effects of fish oil on aortic atherosclerosis, hepatic steatosis and serum lipids in rats.

METHODS

Twenty pregnant Wistar rats were fed with a fish oil-containing diet or standard diet (containing soy bean oil) during pregnancy and lactation and the pups were weaned onto the same diet. Fasting blood samples, hepatic and aortic specimens were taken from pups on day 70 postnatal. Data were analyzed with SPSS software, using t-test, Mann-Whitney test and Spearman correlation coefficient. Values of p < 0.05 were considered significant.

RESULTS

Medians for fatty streak in aorta of fish oil fed and soy bean oil fed pups were 1.00 and 0.00, respectively, and P value was 0.042. Also, medians for ductular cell hyperplasia of liver in fish oil fed and soy bean oil fed pups were 1.00 and 0.00, respectively, and P value was 0.014. Total cholesterol in pups fed with fish oil was 52.20 mg/dl and in pups fed with soy bean oil was 83.90 mg/dl (p < 0.00) and for low density lipoprotein cholesterol (LDL-C) values were 8.79 mg/dl and 13.16 mg/dl, respectively (p = 0.031).

CONCLUSIONS

According to the results of the present study, a diet which provided 15.9% of energy from fish oil as the only source of dietary fat, induced aortic atherosclerosis as well as hepatic steatosis in Wistar rat, although it decreased total cholesterol and LDL-C.