Development of metabolic syndrome and functional state of mesenteric arteries in female rats fed a high-fat diet

Increased adiposity is strongly associated with inflammation. Prior studies have shown that feeding rats a high fat diet (HFD) leads to increased adiposity and inflammation, including elevated circulating tumor necrosis factor alpha (TNFα). The current study was designed to further examine whether markers of inflammation and immune system activation are altered in HFD rats. Rats were fed either a normal chow or HFD for 6 weeks. Comparative whole transcriptome sequencing of isolated aorta from HFD and chow fed rats indicates a significant (p<0.05) 2.8‐fold decrease in the expression of interferon regulatory factor 4 (IRF4), a factor required for lymphocyte activation, suggesting the immune system of these animals is downregulated. Results from western blot analyses show no difference in the expression of the anti‐inflammatory heat shock proteins 60 or 70 (HSP60/70) in erythrocytes or plasma from HFD rats compared to rats fed normal chow (p>0.05). Unlike TNFα, urinary levels of the inflammatory mediator prostaglandin E2 are not different between HFD and chow rats (p>0.05). These findings suggest that, despite elevations in TNFα, the immune system of HFD rats may be partly downregulated. Further studies testing the agglutination response of plasma samples collected from HFD and chow rats will help to assess how well circulating leukocytes respond to immune challenges in overweight animals.

MP76-07 IMPAIRMENT IN P2X2 PURINERGIC SIGNALING AND UP-REGULATING AAPOPTOSIS, AUTOPHAGY AND PYROPTOSIS CONTRIBUTE TO BLADDER DYSFUNCTION AFTER LONG-TERM HIGH-FAT DIET

Maternal high fat diet (HFD) affects the neurodevelopment of offspring and has long-term consequences on cognitive behavior. This study investigated changes occurring in GRP78 and PERK, important markers of endoplasmic reticulum stress (ERS) signaling, in the hippocampus of female adult rats exposed to maternal HFD, and in brain-derived neurotrophic factor (BDNF) signaling, with its important role in the regulation of cognitive behavior, and the potential neuroprotective effects of N-acetylcysteine ​​(NAC) against these changes. A maternal obesity model was created with HFD (60% kcal). NAC (150mg/kg) was administered intragastrically to both the NAC and HFD + NAC groups. The animals were mated at 12weeks of age. The same diet was maintained throughout pregnancy and lactation. All female rat pups were subjected to the water maze test at eight weeks of age. Hippocampal GRP78 and PERK expressions increased in the HFD rats. However, maternal HFD suppressed hippocampal BDNF levels and reduced hippocampal neuronal volume. NAC supplementation reduced GRP78 and PERK expressions and increased BDNF and hippocampal volume values ​​in the HFD + NAC group. At behavioral assessments, rats in the HFD group exhibited decreased memory and learning ability, but the HFD + NAC group exhibited stronger responses than the HFD group. Our findings suggest that the decrease in BDNF expression, which plays a role in memory and learning, after maternal HFD exposure may be due to ERS associated with increased GRP78 and PERK expressions. Furthermore, NAC supplementation may ameliorate the impairment in memory and spatial learning ability by attenuating hippocampal ERS in HFD rats.

Abstracts for Oral Presentation

Coping style predicts the (in)sensitivity for developing hyperinsulinemia on a high fat diet in rats

Higt fat diet can lead to the development of metabolic syndrome (MS). However, the question of the mechanisms of pathophysiological processes in MS has not been studied enough. The aim of the work was to study the effect of a high-fat diet (HFD) on the reactivity of the mesenteric arteries of Wistar rats in vivo, as well as to evaluate the change in the mechanisms of endothelium-dependent arterial dilatation in HFD. The HFD-group of rats (n = 25) received HFD containing 50% animal fat for 10 weeks, the control group (n = 25) received a standard diet. The effect of HFD on endothelium-dependent and endothelium-independent responses of the mesenteric arteries under the action of agonists in the absence and with the use of blockers of NO-synthase (L-NAME), cyclooxygenase (indomethacin), and K+-channels (tetraethylammonium) was assessed using photomicrography and video recording of mesenteric artery diameter in vivo. HFD in rats led to the development of MS, including dyslipidemia, hyperglycemia and insulin resistance, and an increase in blood pressure. MS was accompanied by impaired functional state of the mesenteric arteries. In rats of the HFD group, compared with the control group, there was an increase in the constrictor reaction to phenylephrine by 29%, as well as a decrease in the reactivity of vessels previously contracted by phenylephrine under the action of acetylcholine by 36%. Pre-incubation of vessels with blockers reduced the amplitude of relaxation under the action of acetylcholine, compared with the initial acetylcholine-induced vasorelaxation, in HFD-group rats: with L-NAME – by 47%, L-NAME and indomethacin – by 50%, L-NAME, indomethacin and tetraethylammonium – by 65%; in the control group – by 69, 72 and 83%, respectively. HFD had no significant effect on the amplitude of vasodilation under the action of sodium nitroprusside. Thus, endothelial dysfunction in HFD-treated rats was mediated both by impairment of NO-dependent mechanisms of vasodilation, in particular, by a decrease in NO production by the endothelium, and by a decrease in the effectiveness of ВКСа. The decrease in NO bioavailability in HFD was partially compensated by the activation of endothelial hyperpolarization mechanisms (mediated by IKCa and SKCa activities) in acetylcholine-induced vasodilation.

Bioactive proanthocyanidins have been reported to have several beneficial effects on health in relation to metabolic syndrome, type 2 diabetes, and cardiovascular disease. We studied the effect of grape seed proanthocyanidin extract (GSPE) in rats fed a high fat diet (HFD). This is the first study of the effects of flavonoids on the liver proteome of rats suffering from metabolic syndrome. Three groups of rats were fed over a period of 13 weeks either a chow diet (control), an HFD, or a high fat diet supplemented for the last 10 days with GSPE (HFD + GSPE). The liver proteome was fractionated, using a Triton X-114-based two-phase separation, into soluble and membrane protein fractions so that total proteome coverage was considerably improved. The data from isobaric tag for relative and absolute quantitation (iTRAQ)-based nano-LC-MS/MS analysis revealed 90 proteins with a significant (p < 0.05) minimal expression difference of 20% due to metabolic syndrome (HFD versus control) and 75 proteins due to GSPE treatment (HFD + GSPE versus HFD). The same animals have previously been studied (Quesada, H., del Bas, J. M., Pajuelo, D., Díaz, S., Fernandez-Larrea, J., Pinent, M., Arola, L., Salvadó, M. J., and Bladé, C. (2009) Grape seed proanthocyanidins correct dyslipidemia associated with a high-fat diet in rats and repress genes controlling lipogenesis and VLDL assembling in liver. Int. J. Obes. 33, 1007-1012), and GSPE was shown to correct dyslipidemia observed in HFD-fed rats probably through the repression of hepatic lipogenesis. Our data corroborate those findings with an extensive list of proteins describing the induction of hepatic glycogenesis, glycolysis, and fatty acid and triglyceride synthesis in HFD, whereas the opposite pattern was observed to a large extent in GSPE-treated animals. GSPE was shown to have a wider effect than previously thought, and putative targets of GSPE involved in the reversal of the symptoms of metabolic syndrome were revealed. Some of these novel candidate proteins such as GFPT1, CD36, PLAA (phospholipase A(2)-activating protein), METTL7B, SLC30A1, several G signaling proteins, and the sulfide-metabolizing ETHE1 and SQRDL (sulfide-quinone reductase-like) might be considered as drug targets for the treatment of metabolic syndrome.

Background: Dual Amylin and Calcitonin Receptor Agonists (DACRAs) are treatment candidates for obesity and type 2 diabetes. Recently, a once-weekly DACRA (KBP-A) showed promise, potentially due to its different exposure profile compared to daily DACRA (KBP). Parathyroid hormone, a G-protein-coupled receptor (GPCR) class B agonist, is an example of the exposure profile being critical to the effect. Since KBP and KBP-A also activate GPCR class B, we compared the effects of injection to continuous infusion of short-acting KBP and long-acting KBP-A in obese and diabetic rats to shed light on the role of exposure profiles. Methods: To explore the metabolic benefits of dose optimization, the following dosing profiles were compared in High Fat Diet (HFD)-fed Sprague–Dawley rats and diabetic Zucker Diabetic Fatty (ZDF) rats: (1) KBP dosed once-daily by injection or by continuous infusion in HFD and ZDF rats; (2) KBP injected once-daily and KBP-A injected once every 3rd day (Q3D) in HFD rats; (3) KBP-A injected Q3D or by infusion in ZDF rats. Results: KBP and KBP-A, delivered by either injection or infusion, resulted in similar weight and food intake reductions in HFD rats. In ZDF rats, injection of KBP improved glucose control significantly compared to infusion, while delivery of KBP-A by injection and continuous infusion was comparable in terms of glucose control. Conclusion: different dosing profiles of KBP and KBP-A had no impact on metabolic benefits in HFD rats. In diabetic ZDF rats, KBP by injection instead of infusion was superior, while for KBP-A the effects were similar.

Magnesium (Mg) is an essential mineral required for many physiological processes, including ionic balances in ocular tissues. We compared the effects of different Mg-chelates (Mg oxide, MgO vs. Mg picolinate, MgPic) on retinal function in a high-fat diet (HFD) rats. Forty-two rats were divided into six groups and treated orally for 8 weeks as follows: Control, MgO, MgPic, HFD, HFD + MgO, and HFD + MgPic. Mg was administered at 500 mg of elemental Mg/kg of diet. HFD intake increased the levels of retinal MDA and NF-κB, INOS, ICAM, and VEGF but downregulated Nrf2. However, in rats supplemented with MgO and MgPic, the retinal MDA level was decreased, compared with the control and HFD rats. Activities of antioxidant enzymes (SOD, CAT, and GPx) were increased in HFD animals given Mg-chelates (p < 0.001), MgPic being the most effective. Mg supplementation significantly decreased the expression levels of NF-κB, INOS, ICAM, and VEGF in HFD rats while increasing the level of Nrf2 (p < 0.001). Mg supplementation significantly decreased the levels of NF-κB, INOS, ICAM, and VEGF and increased Nrf2 level in HFD rats (p < 0.001), with stronger effects seen from MgPic. Mg attenuated retinal oxidative stress and neuronal inflammation and could be considered as an effective treatment for ocular diseases.

Background & AimsDietary saturated fatty acids contribute to the development of fatty liver and have pathogenic link to systemic inflammation. We investigated the effects of dietary fat towards the pathogenesis of non-alcoholic fatty liver disease by longitudinal in vivo magnetic resonance spectroscopy (MRS) and in vitro liquid chromatography coupled with mass spectrometry (LC-MS).MethodsAll measurements were performed on rats fed with high fat diet (HFD) and chow diet for twenty four weeks. Longitudinal MRS measurements were performed at the 12th, 18th and 24th weeks. Liver tissues were analyzed by LC-MS, histology and gene transcription studies after terminal in vivo experiments.ResultsLiver fat content of HFD rats for all ages was significantly (P<0.05) higher compared to their respective chow diet fed rats. Unsaturation indices estimated from MRS and LC-MS data of chow diet fed rats were significantly higher (P<0.05) than HFD fed rats. The concentration of triglycerides 48∶1, 48∶2, 50∶1, 50∶2, 50∶3, 52∶1, 52∶2, 52∶3, 54∶3 and 54∶2 was significantly higher (P<0.05) in HFD rats. The concentration for some polyunsaturated triglycerides 54∶7, 56∶8, 56∶7, 58∶11, 58∶10, 58∶9, 58∶8 and 60∶10 was significantly higher (P<0.05) in chow diet fed rats compared to HFD rats. Lysophospholipid concentrations including LPC and LPE were higher in HFD rats at 24 weeks indicating the increased risk of diabetes. The expression of CD36, PPARα, SCD1, SREBF1 and UCP2 were significantly upregulated in HFD rats.ConclusionsWe demonstrated the early changes in saturated and unsaturated lipid composition in fatty liver by in vivo MRS and ex vivo LC-MS. The higher LPC concentration in HFD rats indicated a higher risk of developing diabetes. Early metabolic perturbations causing changes in lipid composition can be evaluated by the unsaturation index and correlated to the non alcoholic fatty liver disease.

Background: The combination of Euphorbia milii (E. milii) flowers and Propolis (tala) of Apis cerana in tea form or EMP tea evidently acts as an immunomodulator, likewise a nontoxic agent for liver and renal in animal model and healthy people during Covid-19 pandemic. Moreover, total cholesterol and MMP-8 level in high fat diet (HFD) rats decreased in relation to the EMP tea. Thus, this study aimed to prove EMP tea in preventing atherosclerosis through molecular aspect in the mRNA of NF-kB and histology aspect in the number of foam cells at HFD rats. Material and Methods: a total of 28 male rats, 100-200 grams in weight (g BW), were sorted into four groups (K0, P1, P2, and P3). After adaptation for a week, K0 were given standard diet; P1 were given standard diet and EMP tea 40 mg/100 g BW daily, while P2 were given HFD 2 g/200 g BW daily; P3 were given HFD 2 g/200 g BW daily and EMP tea 40 mg/ 100 g BW daily for 30 days. Rats were sacrificed at day 31, aorta was collected then subjected to qRT-PCR to measure NF-kB and histological examination to evaluate foam cells. Data are shown in mean and standard deviation (SD). Results: The mRNA of NF- kB level at K0 (0.48 ± 0.28) fg/µl; P1(0.54 ± 0.05) fg/µl; P2 (0.66 ± 0.13) fg/µl; P3 (0.16 ± 0.07) fg/µl. There was a significant difference in the mRNA of NF- kB level (p&lt;0.05) between K0 vs P3; P1 vs P2; P1 vs P3; and P2 vs P3. While the number of foam cells at K0 (0.43 ± 0.2) cells/fv; P1 (0.57 ± 0.2) cells/fv; P2 (54 ± 2.34) cells/fv and P3 (17 ± 2.05) cells/fv. There was a significant difference (p&lt;0.05) in foam cells between K0 vs P2; K0 vs P3; P1 vs P2; P1 vs P3; and P2 vs P3. Conclusion: The mRNA of NF-kB and the number of foam cells in the rat aorta were lower in the administration of EMP tea with doses of 40 mg/100 g BW daily for 30 days in HFD rats.

BackgroundThe composition of a diet can influence myocardial metabolism and development of left ventricular hypertrophy (LVH). The impact of a high-fat diet in chronic left ventricular volume overload (VO) causing eccentric LVH is unknown. This study examined the effects of chronic ingestion of a high-fat diet in rats with chronic VO caused by severe aortic valve regurgitation (AR) on LVH, function and on myocardial energetics and survival.MethodsMale Wistar rats were divided in four groups: Shams on control or high-fat (HF) diet (15 rats/group) and AR rats fed with the same diets (ARC (n = 56) and ARHF (n = 32)). HF diet was started one week before AR induction and the protocol was stopped 30 weeks later.ResultsAs expected, AR caused significant LV dilation and hypertrophy and this was exacerbated in the ARHF group. Moreover, survival in the ARHF group was significantly decreased compared the ARC group. Although the sham animals on HF also developed significant obesity compared to those on control diet, this was not associated with heart hypertrophy. The HF diet in AR rats partially countered the expected shift in myocardial energy substrate preference usually observed in heart hypertrophy (from fatty acids towards glucose). Systolic function was decreased in AR rats but HF diet had no impact on this parameter. The response to HF diet of different fatty acid oxidation markers as well as the increase in glucose transporter-4 translocation to the plasma membrane compared to ARC was blunted in AR animals compared to those on control diet.ConclusionsHF diet for 30 weeks decreased survival of AR rats and worsened eccentric hypertrophy without affecting systolic function. The expected adaptation of myocardial energetics to volume-overload left ventricle hypertrophy in AR animals seemed to be impaired by the high-fat diet suggesting less metabolic flexibility.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2261-14-123) contains supplementary material, which is available to authorized users.

The growing prevalence of obesity poses a significant challenge to public health. This research explored the impact of oat protein isolate (OPI) on mitigating obesity induced by a high-fat diet (HFD) in rats. The results indicate that OPI, administered at a dose of 100 mg/kg, reduced the gain of body weight and fat deposits, ameliorated glucose metabolism, promoted antioxidant capacity, and alleviated inflammation. Results from the 16S rRNA sequencing of fecal samples reveal that OPI mitigated the gut microbiota disorder induced by an HFD, significantly raising the proportion of beneficial genera, such as Ruminococcus, Blautia, Allobaculum, Romboutsia, and Dubosiella. Furthermore, OPI promoted the growth of beneficial bacteria, elevated the production of short-chain fatty acid (SCFAs), and improved glucose and lipid metabolism and reduced inflammation, collectively contributing to its anti-obesity effects. These findings confirm OPI's efficacy in reducing obesity induced by an HFD in rats. Future clinical trials are needed to further validate the efficacy of OPI as a functional food.

BackgroundThe immune system undergoes several alterations of innate and adaptive immunity during ageing. The main features of the aged immune system are a reduced diversity of T cell receptors and a reduced activity of innate immune cells with subsequent changes in adaptive immunity resulting in a less effective, less specific, and dys-regulated immune response and in an increased susceptibility towards infection, malignancy, and autoimmunity. The process is referred to as immunosenescence and is also modulated by environmental modifiers, such as dietary factors. High fat diet (HFD), via direct modulation of immune cell function by fatty acids and/or increased body fat mass, influences immune function. However, it is not clear whether HFD is beneficial or detrimental for the functioning of the ageing immune system.MethodsMale Wistar rats fed with either a high fat diet (HFD 43 en% of fat) or control diet (SD, 25 en% of fat) over up to 24 month and were analyzed for plasma IL-1β, IL-6, TNF, IgM, IgG1, IgA, IgG2a, IgG2b, IgG2c, light chains lambda and kappa, testosterone, prolactin and percentage of splenic B cells and apoptosis rate, respectively.ResultsIn general, all analyzed immunoglobuline isotypes increased with age, except for IgA. This increase was attenuated by HFD. In HFD and SD rats the percentage of B cells in the spleen and also their apoptotic rate was lower in aged as compared to young animals with no additional diet-induced effect. Testosterone and prolactin levels were lower in old animals, as expected. There was a statistical trend towards an increased prolactin/testosterone ratio in middle aged (6–12 monthsnth) HFD rats as compared to SD. IL-6 was neither affected by HFD nor age. On the other hand, HFD rats showed a decrease in IL-1β as compared to SD, which correlated with the above-mentioned suppressive effect on immunoglobulin isotypes, especially IgM.ConclusionIn Wistar rats, HFD reveals an immunosuppressive effect in ageing animals by decreasing immunoglobulins, especially IgM, and IL-1β when compared to SD.

Polysaccharides from Polygonatum kingianum improve glucose and lipid metabolism in rats fed a high fat diet