Biochemical and nutritional overview of diet-induced metabolic syndrome models in rats: what is the best choice?

Spinal cord injury-induced metabolic impairment and steatohepatitis develops in non-obese rats and is exacerbated by premorbid obesity

Impaired sensorimotor functions are prominent complications of spinal cord injury (SCI). A clinically important but less obvious consequence is development of metabolic syndrome (MetS), including increased adiposity, hyperglycemia/insulin resistance, and hyperlipidemia. MetS predisposes SCI individuals to earlier and more severe diabetes and cardiovascular disease compared to the general population, which trigger life-threatening complications (e.g., stroke, myocardial infarcts). Although each comorbidity is known to be a risk factor for diabetes and other health problems in obese individuals, their relative contribution or perceived importance in propagating systemic pathology after SCI has received less attention. This could be explained by an incomplete understanding of MetS promoted by SCI compared with that from the canonical trigger diet-induced obesity (DIO). Thus, here we compared metabolic-related outcomes after SCI in lean rats to those of uninjured rats with DIO. Surprisingly, SCI-induced MetS features were equal to or greater than those in obese uninjured rats, including insulin resistance, endotoxemia, hyperlipidemia, liver inflammation and steatosis. Considering the endemic nature of obesity, we also evaluated the effect of premorbid obesity in rats receiving SCI; the combination of DIO + SCI exacerbated MetS and liver pathology compared to either alone, suggesting that obese individuals that sustain a SCI are especially vulnerable to metabolic dysfunction. Notably, premorbid obesity also exacerbated intraspinal lesion pathology and worsened locomotor recovery after SCI. Overall, these results highlight that normal metabolic function requires intact spinal circuitry and that SCI is not just a sensory-motor disorder, but also has significant metabolic consequences.

Silicon as a Functional Meat Ingredient Improves Jejunal and Hepatic Cholesterol Homeostasis in a Late-Stage Type 2 Diabetes Mellitus Rat Model

Silicon included in a restructured meat (RM) matrix (Si-RM) as a functional ingredient has been demonstrated to be a potential bioactive antidiabetic compound. However, the jejunal and hepatic molecular mechanisms by which Si-RM exerts its cholesterol-lowering effects remain unclear. Male Wistar rats fed an RM included in a high-saturated-fat high-cholesterol diet (HSFHCD) combined with a low dose of streptozotocin plus nicotinamide injection were used as late-stage type 2 diabetes mellitus (T2DM) model. Si-RM was included into the HSFHCD as a functional food. An early-stage TD2M group fed a high-saturated-fat diet (HSFD) was taken as reference. Si-RM inhibited the hepatic and intestinal microsomal triglyceride transfer protein (MTP) reducing the apoB-containing lipoprotein assembly and cholesterol absorption. Upregulation of liver X receptor (LXRα/β) by Si-RM turned in a higher low-density lipoprotein receptor (LDLr) and ATP-binding cassette transporters (ABCG5/8, ABCA1) promoting jejunal cholesterol efflux and transintestinal cholesterol excretion (TICE), and facilitating partially reverse cholesterol transport (RCT). Si-RM decreased the jejunal absorptive area and improved mucosal barrier integrity. Consequently, plasma triglycerides and cholesterol levels decreased, as well as the formation of atherogenic lipoprotein particles. Si-RM mitigated the dyslipidemia associated with late-stage T2DM by Improving cholesterol homeostasis. Silicon could be used as an effective nutritional approach in diabetic dyslipidemia management.

Oat protein modulates cholesterol metabolism and improves cardiac systolic function in high fat, high sucrose fed rats

Oats are recognized to provide many health benefits that are mainly associated with its dietary fibre, β-glucan. However, the protein derived from oats is largely understudied with respect to its ability to maintain health and attenuate risk factors of chronic diseases. The goal of the current study was to investigate the metabolic effects of oat protein consumption in lieu of casein as the protein source in high fat, high sucrose (HF/HS) fed Wistar rats. Four-week-old rats were divided into three groups and were fed three different experimental diets: a control diet with casein as the protein source, an HF/HS diet with casein, or an HF/HS diet with oat protein for 16 weeks. Heart structure and function were determined by echocardiography. Blood pressure measurements, an oral glucose tolerance test, and markers of cholesterol metabolism, oxidative stress, inflammation, and liver and kidney damage were also performed. Our study results show that incorporation of oat protein in the diet was effective in preserving systolic heart function in HF/HS fed rats. Oat protein significantly reduced serum total and low-density lipoprotein cholesterol levels. Furthermore, oat protein normalized liver HMG-CoAR activity, which, to our knowledge, is the first time this has been reported in the literature. Therefore, our research suggests that oat protein can provide hypocholesterolemic and cardioprotective benefits in a diet-induced model of metabolic syndrome.

Metabolic Effects of Short-Term High-Fat Intake Vary Depending on Dietary Amino Acid Composition

Background

It is generally accepted that excessive fat intake has undesirable effects on the energy metabolism of our body. Dietary amino acid composition is also critical to the regulation of lipid metabolism.

Objectives

This study aimed to investigate whether high-fat diets (HFDs) with different amino acid deficiencies lead to different metabolic outcomes.

Methods

Six-wk-old male Wistar rats were fed either a control diet (CN; 3.7 kcal/g, 12% calories from fat) or HFDs (5.1 kcal/g, 60% calories from fat) with 7 different amino acid compositions [control or methionine, arginine, histidine, lysine, threonine, or branched-chain amino acids (BCAAs) deficient], for 7 d. Tissue weights and lipid accumulation in the liver, skeletal muscle, and adipose tissue were measured, and serum biochemical parameters were analyzed.

Results

Although the food intake of the HFD groups was a little less than that of the CN group, the total calorie intakes were comparable among the groups, except for histidine-deficient and BCAA-deficient groups. In rats fed am HFD with a control amino acid composition (HFCN), dramatic increase in triglyceride (TG) accumulation in the liver and serum LDL cholesterol concentration were observed compared with the CN group. However, when the arginine content in the diet was reduced, liver TG accumulation was completely inhibited, with no apparent effects on serum lipoprotein-cholesterol concentrations. Meanwhile, deficiency of the other amino acids, such as threonine, reversed HFD-induced upregulation of serum LDL cholesterol.

Conclusions

It is observed that although the rats ingested an excessive amount of fat, neither ectopic fat accumulation nor dyslipidemia were always induced at least in the short term; hence, the consequent metabolic change was dependent on the dietary amino acid composition. These findings introduce an important perspective regarding HFD regimens in both scientific and clinical contexts.

DNA Aptamer Raised against Advanced Glycation End Products Improves Sperm Concentration, Motility, and Viability by Suppressing Receptors for Advanced Glycation End Product-Induced Oxidative Stress and Inflammation in the Testes of Diabetic Mice

Type 2 diabetes mellitus (T2DM) is a risk factor for male infertility, but the underlying molecular mechanisms remain unclear. Advanced glycation end products (AGEs) are pathogenic molecules for diabetic vascular complications. Here, we investigated the effects of the DNA aptamer raised against AGEs (AGE-Apt) on testicular and sperm abnormalities in a T2DM mouse model. KK-Ay (DM) and wild-type (non-DM) 4- and 7-week-old male mice were sacrificed to collect the testes and spermatozoa for immunofluorescence, RT-PCR, and histological analyses. DM and non-DM 7-week-old mice were subcutaneously infused with the AGE-Apt or control-aptamer for 6 weeks and were then sacrificed. Plasma glucose, testicular AGEs, and Rage gene expression in 4-week-old DM mice and plasma glucose, testicular AGEs, oxidative stress, and pro-inflammatory gene expressions in 7-week-old DM mice were higher than those in age-matched non-DM mice, the latter of which was associated with seminiferous tubular dilation. AGE-Apt did not affect glycemic parameters, but it inhibited seminiferous tubular dilation, reduced the number of testicular macrophages and apoptotic cells, and restored the decrease in sperm concentration, motility, and viability of 13-week-old DM mice. Our findings suggest that AGEs-Apt may improve sperm abnormality by suppressing AGE-RAGE-induced oxidative stress and inflammation in the testes of DM mice.

Vitamin D3 mitigates type 2 diabetes induced by a high carbohydrate-high fat diet in rats: Role of the purinergic system

This study evaluated the effect of vitamin D3 (VIT D3) supplementation on the enzymatic activities and density of ectonucleoside triphosphate diphosphohydrolase (E-NTPDase), ecto-5-nucleotidase (E-5'-NT), adenosine deaminase (ADA), as well as the density of P2 × 7R, P2Y12R, A1R, A2AR receptors, IL-1β, and oxidative parameters in type 2 diabetic rats. Forty male Wistar rats were fed a high carbohydrate-high fat diet (HCHFD) and received an intraperitoneal injection containing a single dose of streptozotocin (STZ, 35 mg/kg). Animals were divided into four groups: 1) control; 2) control/VIT D3 12 µg/kg; 3) diabetic; and 4) diabetic/VIT D3 12 µg/kg. Results show that VIT D3 reduced blood glucose, ATP hydrolysis, ADA activity, P2Y12R density (platelets), as well as ATP, ADP, and AMP hydrolysis and ADA activity (synaptosomes). Moreover, VIT D3 increased insulin levels and AMP hydrolysis (platelets) and improved antioxidant defense. Therefore, we suggest that VIT D3 treatment modulates hyperglycemia-induced changes via purinergic enzymes and receptor expression, consequently attenuating insulin homeostasis dysregulation in the diabetic state.

Comparative Screening of the Liver Gene Expression Profiles from Type 1 and Type 2 Diabetes Rat Models

Experimental animal models of diabetes can be useful for identifying novel targets related to disease, for understanding its physiopathology, and for evaluating emerging antidiabetic treatments. This study aimed to characterize two rat diabetes models: HFD + STZ, a high-fat diet (60% fat) combined with streptozotocin administration (STZ, 35 mg/kg BW), and a model with a single STZ dose (65 mg/kg BW) in comparison with healthy rats. HFD + STZ- induced animals demonstrated a stable hyperglycemia range (350-450 mg/dL), whereas in the STZ-induced rats, we found glucose concentration values with a greater dispersion, ranging from 270 to 510 mg/dL. Moreover, in the HFD + STZ group, the AUC value of the insulin tolerance test (ITT) was found to be remarkably augmented by 6.2-fold higher than in healthy animals (33,687.0 ± 1705.7 mg/dL/min vs. 5469.0 ± 267.6, respectively), indicating insulin resistance (IR). In contrast, a more moderate AUC value was observed in the STZ group (19,059.0 ± 3037.4 mg/dL/min) resulting in a value 2.5-fold higher than the average exhibited by the control group. After microarray experiments on liver tissue from all animals, we analyzed genes exhibiting a fold change value in gene expression <-2 or >2 (p-value <0.05). We found 27,686 differentially expressed genes (DEG), identified the top 10 DEGs and detected 849 coding genes that exhibited opposite expression patterns between both diabetes models (491 upregulated genes in the STZ model and 358 upregulated genes in HFD + STZ animals). Finally, we performed an enrichment analysis of the 849 selected genes. Whereas in the STZ model we found cellular pathways related to lipid biosynthesis and metabolism, in the HFD + STZ model we identified pathways related to immunometabolism. Some phenotypic differences observed in the models could be explained by transcriptomic results; however, further studies are needed to corroborate these findings. Our data confirm that the STZ and the HFD + STZ models are reliable experimental models for human T1D and T2D, respectively. These results also provide insight into alterations in the expression of specific liver genes and could be utilized in future studies focusing on diabetes complications associated with impaired liver function.

Hypolipidemic effect and modulation of hepatic enzymes by different edible oils in obese Wistar rats

The current study assessed the hypolipidemic effect and modulation of hepatic enzymes by different edible oils in obese Wistar rats. In order to conduct this study, 36 Wistar rats that were collected at 5 weeks of age and weighed an average of 70 g were split into two groups: 28 of them were fed a high-fat diet (HFD) and 8 of them were fed a control diet. After 5 weeks of feeding, rats from the HFD (obese, n = 4) and the control diet group (n = 4) were sacrificed. Subsequently, the rest of obese rats (n = 24) were separated into six groups, including the continuing high-fat (CHF) diet group, rice bran oil (RBO) diet group, olive oil (OO) diet group, soybean oil (SO) diet group, cod liver oil (CLO) diet group, and sunflower oil (SFO) diet group, and the continuing control diet group (n = 4). Rats from each group were sacrificed following an additional 5 weeks, and all analytical tests were carried out. The results found that the interventions of RBO, CLO, and SFO in obese rats reduced their body weight non-significantly when compared with CHF. It was also observed that a non-significant reduction in weight of the heart, AAT, and EAT occurred by RBO, OO, SO, and CLO, while SFO reduced the AAT level significantly (p < 0.05). Besides, RBO, OO, SO, CLO, and SFO decreased IBAT and liver fat significantly compared to CHF. Similarly, the administration of RBO, OO, SO, and CLO reduced ALT significantly. RBO reduced GGT (p < 0.05) significantly, but other oils did not. The given oil has the efficiency to reduce TC, TAG, and LDL-C but increase HDL-C significantly. These findings suggest that different edible oils can ameliorate obesity, regulate lipid profiles, and modulate hepatic enzymes.

Consumption of a Taiwanese cafeteria diet induces metabolic disorders and fecal flora changes in obese rats

OBJECTIVES

Among diet-induced obesity animal models, the cafeteria diet, which contains human junk food and processed foods, is a popular experimental animal diets in Western countries. Consumption of a cafeteria diet can lead to the development of obesity and non-alcoholic liver disease in as soon as 2 mo, which more accurately reflects human eating patterns. The aim of this study was to establish a Taiwanese cafeteria diet and compare it with a traditional lard-based, 60% high-fat diet in a 12-wk animal model.

METHODS

Six-wk-old male Wistar rats were assigned to the following three groups: control diet (C; LabDiet 5001); high-fat diet (HFD; 60% HFD); and the Taiwanese cafeteria diet (CAF).

RESULTS

At the end of the study, weight gain and steatosis were observed in the HF and CAF groups. Compared with the HFD group, rats in the CAF group showed significantly higher plasma triacylglycerol concentrations and insulin resistance, which may have been correlated with increased inflammatory responses. Significantly lower hepatic sterol regulatory element-binding protein-1c and insulin receptor substrate-1 protein expressions were observed in the CAF group compared with the HFD group. Additionally, disruption of the microbiotic composition followed by increased obesity-related bacteria was observed in the CAF group.

CONCLUSIONS

The present study confirmed that the Taiwanese cafeteria diet-induced rat model provided a potential platform for investigating obesity-related diseases.

Different Effects of High-Fat/High-Sucrose and High-Fructose Diets on Advanced Glycation End-Product Accumulation and on Mitochondrial Involvement in Heart and Skeletal Muscle in Mice

Diets with an elevated content of fat, sucrose, or fructose are recognized models of diet-induced metabolic alterations, since they induce metabolic derangements, oxidative stress, and chronic low-grade inflammation associated with local and systemic accumulation of advanced glycation end-products (AGEs). This study used four-week-old C57BL/6 male mice, randomly assigned to three experimental dietary regimens: standard diet (SD), high-fat high-sucrose diet (HFHS), or high fructose diet (HFr), administered for 12 weeks. Plasma, heart, and tibialis anterior (TA) skeletal muscle were assayed for markers of metabolic conditions, inflammation, presence of AGEs, and mitochondrial involvement. The HFHS diet induced a tissue-specific differential response featuring (1) a remarkable adaptation of the heart to HFHS-induced heavy oxidative stress, demonstrated by an increased presence of AGEs and reduced mitochondrial biogenesis, and efficaciously counteracted by a conspicuous increase in mitochondrial fission and PRXIII expression; (2) the absence of TA adaptation to HFHS, revealed by a heavy reduction in mitochondrial biogenesis, not counteracted by an increase in fission and PRXIII expression. HFr-induced mild oxidative stress elicited tissue-specific responses, featuring (1) a decrease in mitochondrial biogenesis in the heart, likely counteracted by a tendency for increased fission and (2) a mild reduction in mitochondrial biogenesis in TA, likely counteracted by a tendency for increased fusion, showing the adaptability of both tissues to the diet.

Benefits of Chronic Administration of a Carbohydrate-Free Diet on Biochemical and Morphometric Parameters in a Rat Model of Diet-Induced Metabolic Syndrome

Carbohydrate intake restriction positively affects markers related to metabolic syndrome (MS). However, the effects of long-term carbohydrate-free diets (CFD) have yet to be studied. The main objective of this study was to report the effects on biochemical and morphometric parameters in a rat model of MS. Male Wistar rats were initially divided into two groups: the standard diet group (SD, n = 20); and the MS group (n = 30) fed a high-glucose diet. Ten animals from each group were sacrificed after 20 weeks on their respective diets to verify MS development. The remaining MS animals were divided into two subgroups: one continued with the MS diet (n = 10); and the other transitioned to a carbohydrate-free diet (MS + CFD group, n = 10) for 20 more weeks. At week 40, parameters, including glucose, insulin, lipid profile, ketone bodies, C-reactive protein (CRP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea, creatinine, liver and muscle glycogen, and serum, hepatic, renal, and pancreatic malondialdehyde (MDA) levels were assessed. Transitioning to CFD resulted in decreased caloric intake and body weight, with normalized parameters including MDA, insulin, lipid profile, ALT, liver glycogen, creatinine, and CRP levels. This shift effectively reversed the MS-induced alterations, except for glycemia and uremia, likely influenced by the diet's high protein content stimulating gluconeogenesis. This research underscores the potential benefits of long-term carbohydrate restriction in mitigating MS-related markers.

Red and golden tomato administration improves fat diet-induced hepatic steatosis in rats by modulating HNF4α, Lepr, and GK expression

Introduction

Nonalcoholic fatty liver disease (NAFLD), characterized by lipid accumulation within hepatocytes exceeding 5% of liver weight, is strongly related to metabolic disorders, obesity, and diabetes and represents a health emergency worldwide. There is no standard therapy available for NAFLD. Lifestyle intervention, including phytonutrient intake, is key in preventing NAFLD development and progression.

Methods

We used a rat model of NAFLD to evaluate the effect of dietary supplementation with red tomato (RT) and golden tomato (GT)-a patented mix of fruit with varying degrees of ripeness and particularly rich in naringenin and chlorogenic acid-after steatosis development. We assessed the effects on body weight, metabolic profile, and hepatic steatosis.

Results and discussion

We found a correlation between the amelioration of all the parameters and the liver gene expression. Our results showed that, together with the reversion of steatosis, the consumption of RT and GT can cause a significant reduction in triglycerides, low-density lipoprotein-cholesterol, fasting glucose, and homeostasis model assessment index. Meanwhile, we observed an increase in high-density lipoprotein-cholesterol according to the amelioration of the general lipidic profile. Regarding hepatic gene expression, we found the upregulation of Gk and Hnf4α involved in metabolic homeostasis, Lepr involved in adipokine signaling, and Il6 and Tnf involved in inflammatory response. Taken together, our results suggest that dietary intake of red and golden tomatoes, as a nutraceutical approach, has potential in preventing and therapeutics of NAFLD.

Differences in Cholesterol Metabolism, Hepato-Intestinal Aging, and Hepatic Endocrine Milieu in Rats as Affected by the Sex and Age

Age and sex influence serum cholesterol levels, but the underlying mechanisms remain unclear. To investigate further, we measured cholesterol, precursors (surrogate synthesis markers), degradation products (oxysterols and bile acid precursors) in serum, the liver, jejunum, and ileum, as well as serum plant sterols (intestinal absorption markers) in male and female Wistar rats (4 and 24 months old). The analysis of histomorphometric and oxidative stress parameters (superoxide dismutase, catalase, glutathione-related enzyme activities, lipid peroxide, and protein carbonyl concentrations) in the liver and jejunum offered further insights into the age- and sex-related differences. The hepatic gene expression analysis included AR, ERα, and sex-specific growth hormone-regulated (Cyp2c11 and Cyp2c12) and thyroid-responsive (Dio1, Tbg, and Spot 14) genes by qPCR. We observed age-related changes in both sexes, with greater prominence in females. Aged females had significantly higher serum cholesterol (p < 0.05), jejunum cholesterol (p < 0.05), and serum plant sterols (p < 0.05). They exhibited poorer hepato-intestinal health compared with males, which was characterized by mild liver dysfunction (hydropic degeneration, increased serum ALT, p < 0.05, and decreased activity of some antioxidant defense enzymes, p < 0.05), mononuclear inflammation in the jejunal lamina propria, and age-related decreases in jejunal catalase and glutathione peroxidase activity (p < 0.05). Aged females showed increased levels of 27-hydroxycholesterol (p < 0.05) and upregulated ERα gene expression (p < 0.05) in the liver. Our study suggests that the more significant age-related increase in serum cholesterol in females is associated with poorer hepato-intestinal health and increased jejunal cholesterol absorption. The local increase in 27-hydroxycholesterol during aging might reduce the hepatoprotective effects of endogenous estrogen in the female liver.

Metabolic Markers Associated with Progression of Type 2 Diabetes Induced by High-Fat Diet and Single Low Dose Streptozotocin in Rats

Science is still searching for readily available, cost-effective biomarkers to assess metabolic disorders occurring before the onset and during the development of type-2 diabetes (T2DM). The aim of the present study was to induce T2DM in rats through a high-fat diet, followed by a single administration of low dose streptozotocin (STZ), and make an assessment of the development of the disease. The rats were divided into two groups-experimental and control-and were monitored for a period of 10 days. Changes in anthropometric parameters, glucose, insulin, lipids, uric acid, advanced oxidation protein products (AOPP), as well as the histological changes in the liver and pancreas, were recorded. To assess insulin resistance, we used the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and beta cell function (HOMA-β) and visceral obesity-adiposity index (AI). The data demonstrate that the increasing values of glucose, HOMA-IR, AI, total cholesterol, triacylglycerols, low- and very-low-density lipoproteins are important markers of the pre-diabetic state. The stable hyperglycemia and increased levels of TC, TG, VLDL, LDL, uric acid and AOPP in experimental rats strongly suggest the development of T2DM. HOMA-IR, HOMA-β, AI, and uric acid are reliable criteria for T2DM in rats.

"Golden" Tomato Consumption Ameliorates Metabolic Syndrome: A Focus on the Redox Balance in the High-Fat-Diet-Fed Rat

Tomato fruits defined as "golden" refer to a food product harvested at an incomplete ripening stage with respect to red tomatoes at full maturation. The aim of this study is to explore the putative influence of "golden tomato" (GT) on Metabolic Syndrome (MetS), especially focusing on the effects on redox homeostasis. Firstly, the differential chemical properties of the GT food matrix were characterized in terms of phytonutrient composition and antioxidant capacities with respect to red tomato (RT). Later, we assessed the biochemical, nutraceutical and eventually disease-modifying potential of GT in vivo in the high-fat-diet rat model of MetS. Our data revealed that GT oral supplementation is able to counterbalance MetS-induced biometric and metabolic modifications. Noteworthy is that this nutritional supplementation proved to reduce plasma oxidant status and improve the endogenous antioxidant barriers, assessed by strong systemic biomarkers. Furthermore, consistently with the reduction of hepatic reactive oxygen and nitrogen species (RONS) levels, treatment with GT markedly reduced the HFD-induced increase in hepatic lipid peroxidation and hepatic steatosis. This research elucidates the importance of food supplementation with GT in the prevention and management of MetS.

Brown adipose tissue transcriptome unveils an important role of the Beta-alanine/alamandine receptor, MrgD, in metabolism

Alamandine is a recently described heptapeptide component of the renin-angiotensin system (RAS), and its effects are mediated by the receptor Mas-related G protein-coupled receptor D (MrgD) RAS represents an important link between obesity and its consequences by directly modulating the thermogenesis and brown adipose tissue (BAT) function. The alamandine/MrgD metabolic effects and signaling remain unexplored. In this context, the main goal of the present study was to assess the metabolic consequences of MrgD genetic ablation in C57BL6/J mice by evaluating brown adipose tissue RNA sequencing. The main results showed that MrgD-KO mice have diminished brown adipose tissue and that a high-glucose diet (HG) decreased both circulating alamandine levels and MrgD expression in BAT from wild-type mice (WT). BAT transcriptome reveals that MrgD-KO HG mice regulated 45 genes, while WT HG mice regulated 1,148 genes. MrgD-KO mice fed a standard diet (ST) compared with WT ST mice regulated 476 genes, of which 445 genes were downregulated. BAT uses the MrgD receptor to display a normal pattern of gene expression and to respond, like WT mice, to an HG diet. In conclusion, the MrgD signaling is important for the metabolic regulation and manutention of BAT functionality.

Effect of Agave Fructan Bioconjugates on Metabolic Syndrome Parameters in a Murine Model

Metabolic syndrome is a complex disorder that combines abdominal obesity, dyslipidemia, hypertension, and insulin resistance. Metabolic syndrome affects 25% of the world's population. Agave fructans have shown positive effects on alterations related to metabolic syndrome, so some investigations have focused on their bioconjugation with fatty acids to increase their biological activity. The objective of this work was to evaluate the effect of agave fructan bioconjugates in a rat model with metabolic syndrome. Agave fructans enzymatically bioconjugated (acylated via food-grade lipase catalysis) with propionate or laurate were administered orally for 8 weeks in rats fed a hypercaloric diet. Animals without treatment were used as the control group, as well as animals fed with a standard diet. The data indicate that the group of animals treated with laurate bioconjugates showed a significant decrease in glucose levels, systolic pressure, weight gain, and visceral adipose tissue, as well as a positive effect of pancreatic lipase inhibition. These results allow us to demonstrate the potential of agave bioconjugates, particularly laurate bioconjugates, for the prevention of diseases associated with metabolic syndrome.

Bergamot (Citrus bergamia) leaf extract improves metabolic, antioxidant and anti-inflammatory activity in skeletal muscles in a metabolic syndrome experimental model

Metabolic Syndrome (MetS), inflammation and oxidative stress contribute to impairment of skeletal muscle function. Bergamot (Citrus bergamia) leaf extract (BLE) has shown protective effects against comorbidities associated with MetS through its anti-inflammatory and antioxidant effects. The aim of this work was to elucidate the antioxidant and anti-inflammatory activity of BLE in skeletal muscles in an experimental model of MetS. Once metabolic syndrome was diagnosed, animals were divided into groups receiving different treatments for 10 weeks, including control diet (n = 10), control + BLE (n = 10), High Sugar-fat diet (HSF) (n = 10), HSF + BLE (n = 10). Evaluation included nutritional, metabolic and hormonal analyses, along with measurements of inflammatory status and oxidative stress in soleus and extensor digitorum longus (EDL) muscles. BLE showed positive metabolic effects, with a reduction of plasma triglycerides and insulin resistance and an increase in high-density lipoprotein cholesterol, and protective activity against oxidative stress and inflammation in Soleus and EDL muscles in animals with MetS.

Effects of different diets used to induce obesity/metabolic syndrome on bladder function in rats

Preclinical and human studies on the relationship between obesity/metabolic syndrome (MetS) and lower urinary tract dysfunction (LUTD) are inconsistent. We compared the temporal effects of feeding four different diets used to induce obesity/MetS, including 60% fructose, 2% cholesterol +10% lard, 30% fructose + 20% lard, or 32.5% lard diet, up to 42 wk, on metabolic parameters and bladder function in male Sprague-Dawley rats. Rats fed a 30% fructose + 20% lard or 32.5% lard diet consumed less food (grams), but only the 32.5% lard diet group took in more calories. Feeding rats a 60% fructose or 30% fructose + 20% lard diet led to glucose intolerance and increased blood pressure. Higher body weight and increased cholesterol levels were observed in the rats maintained on a 2% cholesterol +10% lard diet, whereas exposure to a 32.5% lard diet affected most of the above parameters. Voiding behavior measurement showed that voiding frequency and the total voided volume were lower in the experimental diet groups except for the 30% fructose + 20% lard group. The mean voided volume was lower in the 30% fructose + 20% lard and 32.5% lard groups compared with the control group. Cystometric analysis revealed a decreased bladder capacity, mean voided volume, intermicturition interval, and compliance in the 32.5% lard diet group. In conclusion, experimental diets including 60% fructose, 30% fructose + 20% lard, or 2% cholesterol + 10% lard diet differently affected physiological and metabolic parameters and bladder function to a limited extent, while exposure to a 32.5% lard diet had a greater impact.

The effects of Dendrobium species on the metabolic syndrome: A review

Metabolic syndrome (MetS) is known as a global health challenge with different types of health conditions such as hypertension, hyperglycemia, the increasing prevalence of obesity, and hyperlipidemia. Despite much recent scientific progress, the use of traditional herbal medicines with fewer side effects is increasing worldwide. Dendrobium, the second-largest orchid genus, has been used as a natural source of drugs for the treatment of MetS. The beneficial effects of Dendrobium, including anti-hypertension, anti-hyperglycemia, anti-obesity, and anti-hyperlipidemic against MetS have been shown in the scientific evidence. The anti-oxidant and lipid-lowering effects of Dendrobium modulate hyperlipidemia via reducing lipid accumulation and maintaining lipid metabolism. Restoring pancreatic beta cells and regulating the insulin signaling pathway are involved in its antidiabetic properties. The hypotensive effects contribute to increasing nitric oxide (NO) generation and inhibiting extracellular signal-regulated kinase (ERK) signaling. More research projects, especially clinical trials, are needed to investigate the safety, efficacy, and pharmacokinetics of Dendrobium in patients. This review article provides, for the first time, comprehensive information about the efficacy of different species of Dendrobium. The described species can be a source of medicines for the treatment of MetS, which are reported in various evidence.

Correlation of Metabolic Syndrome with Redox Homeostasis Biomarkers: Evidence from High-Fat Diet Model in Wistar Rats

Metabolic Syndrome (MetS) is an extremely complex disease. A non-balanced diet such as high-fat diet (HFD) induces metabolic dysfunction that could modify redox homeostasis. We here aimed at exploring redox homeostasis in male Wistar rats, following 8 weeks of HFD, correlating the eventual modification of selected biomarkers that could be associated with the clinical manifestations of MetS. Therefore, we selected parameters relative to both the glucose tolerance and lipid altered metabolism, but also oxidative pattern. We assessed some biomarkers of oxidative stress i.e., thiols balance, lipid peroxidation and antioxidant barriers, via the use of specific biochemical assays, individuating eventual cross correlation with parameters relative to MetS through a Principal Component Analysis (PCA). The present study shows that 8 weeks of HFD induce MetS in rats, altering glucose and lipid homeostasis and increasing visceral adipose tissue, but also impairing the physiological antioxidant responses that could not counteract the oxidative stress condition. Crucially, cross-correlation analysis suggested that the assessment of specific oxidative stress parameters reported here can provide information comparable to the more widely acquired biomarkers of Mets such as glucose tolerance. Lastly, hepatic steatosis in association with the oxidative stress condition was also highlighted by histological analysis. This research will elucidate the fundamental impact of these oxidative stress parameters on MetS induced in the HFD rat model, tracing paths for developing prevention approaches.

Vanin 1 Gene Role in Modulation of iNOS/MCP-1/TGF-β1 Signaling Pathway in Obese Diabetic Patients

INTRODUCTION

Cysteamine, a powerful endogenous antioxidant, is produced mostly by the vanin-1 with pantetheinase activity. With regard to glycemic, inflammatory, and redox factors, the current study sought to evaluate the association between the expression of the vanin-1 gene, oxidative stress, and inflammatory and iNOS signaling pathway in obese diabetic patients.

METHODS

We enrolled 67 male subjects with an average age of 53.5 ± 5.0 years, divided into 4 groups according to the WHO guideline. We determined their plasma levels of glucose, insulin, IRI, HbA1c, TC, TG, HDL-C, TNF- α, MCP-1, TGF-β1, SOD, CAT, and TBARs, as well as expression of the iNOS and Vanin1 genes.

RESULTS

Overweight and obese class I and II diabetics had significantly higher levels of plasma glucose, insulin, HbA1c, TNF-α, MCP-1, TGF-β1, CAT, and TBAR as well as iNOS and vanin-1 gene expression compared to healthy control individuals. In addition, as compared to healthy control individuals, overweight obese class I and II diabetics' plasma HDL-C levels and blood SOD activity were significantly lower. In addition, ultrasound and computed tomography showed that the presence of a mild obscuring fatty liver with mild hepatic echogenicity appeared in overweight, class I and II obese diabetic patients.

CONCLUSION

These findings provide important information for understanding the correlation between Vanin 1 and glycemic, inflammatory, and redox factors in obese patients. Furthermore, US and CT analysis were performed to visualize the observed images of fatty liver due to obesity.

Cytokine modulation by etanercept ameliorates metabolic syndrome and its related complications induced in rats administered a high-fat high-fructose diet

The aim of the present study was to investigate the effect of etanercept (ETA)-an anti-tumor necrosis factor α (TNF-α) monoclonal antibody-on metabolic disorders such as obesity, hypertension, dyslipidemia, and insulin resistance associated with the metabolic syndrome (MS). MS was induced in rats via high-fat high-fructose (HFHF) administration for 8 weeks. Rats were divided into three groups: negative control, HFHF model, and ETA-treated groups [HFHF + ETA (0.8 mg/kg/twice weekly, subcutaneously) administered in the last 4 weeks]. ETA effectively diminished the prominent features of MS via a significant reduction in the percent body weight gain along with the modulation of adipokine levels, resulting in a significant elevation of serum adiponectin consistent with TNF-α and serum leptin level normalization. Moreover, ETA enhanced dyslipidemia and the elevated blood pressure. ETA managed the prominent features of MS and its associated complications via the downregulation of the hepatic inflammatory pathway that induces nonalcoholic steatohepatitis (NASH)-from the expression of Toll-like receptor 4, nuclear factor kappa B, and TNF-α until that of transforming growth factor-in addition to significant improvements in glucose utilization, insulin sensitivity, and liver function parameter activity and histopathological examination. ETA was effective for the treatment of all prominent features of MS and its associated complications, such as type II diabetes mellitus and NASH.

The Effect of Alternating High-Sucrose and Sucrose Free-Diets, and Intermittent One-Day Fasting on the Estrous Cycle and Sex Hormones in Female Rats

Relationships between diet, sex hormone concentrations, and the estrous cycle are important from the perspective of infertility and estrogen-dependent disease prevention and treatment. Four dietary interventions reflecting modern eating behaviors were explored. The study involved 50 female rats divided into five feeding groups. The impact of the amount of sucrose consumed (9% and 18% of the dietary energy content), alternating high-sucrose and sucrose-free diets, and a high-sucrose diet combined with intermittent one-day fasting on the estrous cycle and sex hormone concentrations in female rats was assessed. Even low amounts of dietary sucrose (9% of the dietary energy content) were found to lead to increased estradiol (E2) concentrations and decreased progesterone (Pg) concentrations. A high-sucrose diet, even when periodically applied, additionally led to a reduced concentration of luteinizing hormone (LH). The largest changes in the hormones tested were observed with one-day fasting coupled with the high-sucrose diet; in addition, the estrous phase was shortened and the estrous cycle was disrupted. The results of this study show that both the amount of dietary sucrose and also its uptake pattern affect the estrous cycle and sex hormone concentrations in female rats.

Morphological changes in the heart and aorta of rats with diet-induced metabolic syndrome

Aim. To identify early morphological changes in the heart and aorta of rats with experimental metabolic syndrome induced by a high-fat and high-carbohydrate diet (HFHCD).

Materials and methods. The study was carried out on male Wistar rats. The animals were divided into two groups: a control group (n = 10) and an experimental group (n = 10). The rats from the control group were fed with a standard laboratory diet. The rats from the experimental group received HFHCD for 12 weeks. Body weight, blood pressure (BP), and individual parameters of carbohydrate and lipid metabolism were assessed in the rats.   A histologic examination of the heart and aorta in the animals was performed.

Results. Feeding rats with HFHCD led to an increase in body weight, elevation of BP, obesity, hyperglycemia, and triglyceridemia. The histologic examination of the heart in the rats of the experimental group showed signs of vascular disease, lipomatosis, and focal myocardial degeneration. Lipid accumulation in the cells of the media, hyperplasia of adipocytes in the adventitia, and depletion and fragmentation of the elastic lamina were revealed in the aortic wall of the rats receiving HFHCD.

Conclusion. The study indicated that HFHCD is an effective way to model metabolic syndrome. Structural disorders in the heart and aorta may be the mainstay for the development of cardiomyopathy and arterial hypertension in diet-induced metabolic syndrome.

Bergamot leaf extract treats cardiorenal metabolic syndrome and associated pathophysiological factors in rats fed with a high sugar fat diet

Bergamot citrus (Citrus bergamia Risso et Poiteau), have been used as a strategy to prevent or treat comorbidities associated with metabolic syndrome parameters, such as cardiorenal metabolic syndrome (CRMS). The aim was to test the effect of bergamot leaf extract on CRMS and associated pathophysiological factors in rats fed with a high sugar-fat diet. Animals were divided into two experimental groups with control diet (Control, n = 30) and high sugar-fat diet (HSF, n = 30) for 20 weeks. Once CRMS was detected, animals were redivided to begin the treatment with Bergamot Leaf Extract (BLE) by gavage (50 mg/kg) for 10 weeks: control diet + placebo (Control, n = 09), control diet + BLE (Control + BLE, n = 09), HSF diet + placebo (HSF, n = 09), HSF + BLE (n = 09). Evaluation included nutritional, metabolic and hormonal analysis; and renal and cardiac parameters. HSF groups presented obesity, dyslipidemia, hypertension, hyperglycemia, hyperinsulinemia, insulin resistance. BLE showed protection against effects on hypertriglyceridemia, insulin resistance, renal damage, and structural and functional alterations of the heart. Conclusion: Bergamot leaf extract shows potential as a therapeutic to treat CRMS in animals fed with a high sugar-fat diet.

Liquorice root extract and isoliquiritigenin attenuate high-fat diet-induced hepatic steatosis and damage in rats by regulating AMPK

Objective: This study compared the ability of Liquorice roots aqueous extract (LRE) and its ingredient, isoliquiritigenin (ISL), in alleviating high-fat diet (HFD)-induced hepatic steatosis and examined if this effect involves activation of AMPK.Materials and methods: Control or HFD-fed rats were treated with the vehicle, LRE (200 mg/kg), or ISL (30 mg/kg) for 8 weeks orally.Results: ISL and LRE reduced HFD-induced hyperglycaemia, improved liver structure, lowered serum and hepatic lipids, and attenuated hepatic oxidative stress and inflammation. In the control and HFD-fed rats, ISL and LRE significantly stimulated the muscular and hepatic mRNA and protein levels of AMPK, improved oral glucose tolerance, reduced hepatic mRNA levels of SREBP1/2, and upregulated hepatic levels of PPARα and Bcl2. These effects were comparable for ISL and LRE and were prevented by co-administration of compound C, an AMPK inhibitor.Discussion and conclusion: ISL and LRE provide an effective theory to alleviate hepatic steatosis through activating AMPK.

Dietary carbohydrates: Pathogenesis and potential therapeutic targets to obesity-associated metabolic syndrome

Metabolic syndrome (MetS) is a common feature in obesity, comprising a cluster of abnormalities including abdominal fat accumulation, hyperglycemia, hyperinsulinemia, dyslipidemia, and hypertension, leading to diabetes and cardiovascular diseases (CVD). Intake of carbohydrates (CHO), particularly a sugary diet that rapidly increases blood glucose, triglycerides, and blood pressure levels is the predominant determining factor of MetS. Complex CHO, on the other hand, are a stable source of energy taking a longer time to digest. In particular, resistant starch (RS) or soluble fiber is an excellent source of prebiotics, which alter the gut microbial composition, which in turn improves metabolic control. Altering maternal CHO intake during pregnancy may result in the child developing MetS. Furthermore, lifestyle factors such as physical inactivity in combination with dietary habits may synergistically influence gene expression by modulating genetic and epigenetic regulators transforming childhood obesity into adolescent metabolic disorders. This review summarizes the common pathophysiology of MetS in connection with the nature of CHO, intrauterine nutrition, genetic predisposition, lifestyle factors, and advanced treatment approaches; it also emphasizes how dietary CHO may act as a key element in the pathogenesis and future therapeutic targets of obesity and MetS.

Enhanced silver nanoparticle-induced pulmonary inflammation in a metabolic syndrome mouse model and resolvin D1 treatment

BACKGROUND

Metabolic syndrome (MetS) exacerbates susceptibility to inhalation exposures such as particulate air pollution, however, the mechanisms responsible remain unelucidated. Previously, we determined a MetS mouse model exhibited exacerbated pulmonary inflammation 24 h following AgNP exposure compared to a healthy mouse model. This enhanced response corresponded with reduction of distinct resolution mediators. We hypothesized silver nanoparticle (AgNP) exposure in MetS results in sustained pulmonary inflammation. Further, we hypothesized treatment with resolvin D1 (RvD1) will reduce exacerbations in AgNP-induced inflammation due to MetS.

RESULTS

To evaluate these hypotheses, healthy and MetS mouse models were exposed to vehicle (control) or AgNPs and a day later, treated with resolvin D1 (RvD1) or vehicle (control) via oropharyngeal aspiration. Pulmonary lung toxicity was evaluated at 3-, 7-, 14-, and 21-days following AgNP exposure. MetS mice exposed to AgNPs and receiving vehicle treatment, demonstrated exacerbated pulmonary inflammatory responses compared to healthy mice. In the AgNP exposed mice receiving RvD1, pulmonary inflammatory response in MetS was reduced to levels comparable to healthy mice exposed to AgNPs. This included decreases in neutrophil influx and inflammatory cytokines, as well as elevated anti-inflammatory cytokines.

CONCLUSIONS

Inefficient resolution may contribute to enhancements in MetS susceptibility to AgNP exposure causing an increased pulmonary inflammatory response. Treatments utilizing specific resolution mediators may be beneficial to individuals suffering MetS following inhalation exposures.

Antidiabetic Effect of Tamarindus indica and Momordica charantia and Downregulation of TET-1 Gene Expression by Saroglitazar in Glucose Feed Adipocytes and Their Involvement in the Type 2 Diabetes-Associated Inflammation In Vitro

To date, there is no satisfactory and effective therapy available to cure type 2 diabetes mellitus (T2DM). This present work is focused on plant extracts and the effect of saroglitazar and TET genes on oxidative stress and inflammation in vitro adipocytes. Aqueous extracts of Tamarindus indica and Momordica charantia seed have shown potent antidiabetic activity that decreases glucose levels in diabetic adipocytes. After seven and fourteen days, the sugar level in the blood was significantly reduced when plant extracts were supplemented. Lipid profiles including total cholesterol (TC), triglyceride (TGL), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very low-density lipoprotein (VLDL) showed a highly significant change as expected in adipocytes treated with glucose compared with controlled adipocytes (P < 0.001). Gene expression of catalase, superoxide dismutase (SOD1, SOD2), and glutathione peroxidase (GPx) are changed twice, thrice, and quadruplet, respectively. The level of interleukin-1 (IL1) and tumor necrosis factor-α (TNF-α) was restored but the interleukin-6 (IL6) and ten-eleven-translocation-1 (TET1) were completely knocked down by the use of saroglitazar. In comparison with the diabetic group, this supplementation significantly increased glycogen content and glucose-6-phosphate dehydrogenase activity. In the extract supplemented group, glucose-6-phosphatase, glucose-oxidizing enzyme, and glucose-phosphorylating enzyme activities were significantly reduced. After seven days of extract supplementation, these parameters were not resettled to a controlled level; however, after 14 days of supplementation, all parameters were restored to the control level. In addition to altering gene expression, TET enzymes may contribute to altered adiposity and its metabolic consequences. The purpose of this study is to examine new ideas and approaches for treating obesity, T2DM, and other associated metabolic disorders.

Delving the Role of Caralluma fimbriata: An Edible Wild Plant to Mitigate the Biomarkers of Metabolic Syndrome

Metabolic syndrome (MS), commonly known as syndrome X or insulin resistance syndrome, is a collection of risk factors for cardiovascular diseases and type II diabetes. MS is believed to impact over a billion individuals worldwide. It is a medical condition defined by visceral obesity, insulin resistance, high blood pressure, and abnormal cholesterol levels, according to the World Health Organization. The current dietary trends are more focused on the use of functional foods and nutraceuticals that are well known for their preventive and curative role against such pathological disorders. Caralluma fimbriata is one such medicinal plant that is gaining popularity. It is a wild, edible, succulent roadside shrub with cactus-like leaves. Besides its main nutrient contents, various bioactive constituents have been identified and linked with positive health outcomes of appetite-suppressing, hypolipidemic, antioxidant, hepatoprotective, and anticancer potentials. Hence, such properties make C. fimbriata an invaluable plant against MS. The current review compiles recent available literature on C. fimbriata's nutritional composition, safety parameters, and therapeutic potential for MS. Summarized data in this review reveals that C. fimbriata remains a neglected plant with limited food and therapeutic applications. Yet various studies explored here do prove its positive health-ameliorating outcomes.

Low molecular weight NGF mimetic GK-2 normalizes the parameters of glucose and lipid metabolism and exhibits a hepatoprotective effect on a prediabetes model in obese Wistar rats

Signs of metabolic syndrome and prediabetes preceding type 2 diabetes are modelled in an experiment using a high-fat diet (HFD). The aim of this work was to study the effect of a low molecular weight systemically active nerve growth factor mimetic, compound GK-2 (hexamethylenediamide bis(N-monosuccinyl-L-glutamyl-L-lysine)), on indicators of abdominal obesity, basal blood glucose level, glucose tolerance, cholesterol and triglyceride blood levels, as well as the morphological structure of the liver in male Wistar rats fed a HFD. Rats were divided into three groups: one of them received standard food (control) and two others were fed a HFD containing 45% fat, 35% carbohydrates and 20% protein, with a total caloric value of 516 kcal/100 g, over 12 weeks. Starting from the 9th week, for the next 4 weeks, one of the HFD groups was treated orally with saline whilst the other group was treated orally with GK-2 at a dose of 5 mg/kg. GK-2 was found to reduce the basal glycemia level and improve glucose tolerance, as well as to reduce the blood level of cholesterol by 30% and that of triglycerides by 28% in comparison with the saline-treated HFD animals. GK-2 reduced the degree of abdominal obesity to the level of the healthy animals and eliminated morphological abnormalities in the liver caused by the HFD. The results of the study determine the feasibility of further GK-2 research as a potential agent for prediabetes treatment.

Metabolic Syndrome: Lessons from Rodent and Drosophila Models

Overweight and obesity are health conditions tightly related to a number of metabolic complications collectively called “metabolic syndrome” (MetS). Clinical diagnosis of MetS includes the presence of the increased waist circumference or so-called abdominal obesity, reduced high density lipoprotein level, elevated blood pressure, and increased blood glucose and triacylglyceride levels. Different approaches, including diet-induced and genetically induced animal models, have been developed to study MetS pathogenesis and underlying mechanisms. Studies of metabolic disturbances in the fruit fly Drosophila and mammalian models along with humans have demonstrated that fruit flies and small mammalian models like rats and mice have many similarities with humans in basic metabolic functions and share many molecular mechanisms which regulate these metabolic processes. In this paper, we describe diet-induced, chemically and genetically induced animal models of the MetS. The advantages and limitations of rodent and Drosophila models of MetS and obesity are also analyzed.

Maternal and Offspring Sugar Consumption Increases Perigonadal Adipose Tissue Hypertrophy and Negatively Affects the Testis Histological Organization in Adult Rats

Sugar intake has been associated with the development of male reproductive pathologies because of the increase and dysfunction in different adipose tissue depots. The establishment of these dysfunctions in the early stages of development is unknown. We evaluated the effect of maternal (pregnancy and lactation) and male offspring (from weaning to adulthood) consumption of 5% sucrose on perigonadal adipose tissue (PAT) and testis in adulthood. Moreover, two rat groups were compared, both including pregnant and lactating females: Control (C—drinking tap water) and sugar (S—consuming 5% sucrose solution). From weaning to adulthood with male offspring, four subgroups were formed: Control Mother → Control and Sugar offspring (CC, CS) and Sugar Mother → Control and Sugar offspring (SC, SS). At 120 postnatal days, the testes and PAT were collected and morphologically described. Furthermore, we quantified the number and cross-sectional area of perigonadal adipocytes and their distribution. We found that the males from SC and SS groups showed high PAT weight (p < 0.005), a high number (p < 0.05), and a relative frequency of large adipocytes (p < 0.05), establishing these results during gestational and lactation stages, and enhancing in adulthood since postnatal diet and its interaction. More macrophages, mast cells, and Leydig cells were observed in the interstitial space of the testis for the CS, SC, and SS groups, concluding that consumption of a high-carbohydrate maternal diet, program hypertrophy processes in adult PAT, developing and enhancing with sugar consumption during postnatal life. Furthermore, they are associated with inflammatory processes within the interstitial space of the testis.

The anti-diabetic potential of betaine. Mechanisms of action in rodent models of type 2 diabetes

Betaine (N, N, N-trimethylglycine) is an amino-acid derivative exerting numerous beneficial effects on the organism. This compound is found in human and animal diets but is also endogenously generated. However, its synthesis may be insufficient to maintain or improve health. Moreover, the tissue content of betaine reduces under some pathological conditions, such as type 2 diabetes. This decrease may be, however, easily alleviated by dietary betaine supplementation. Rodent studies provided evidence that betaine effectively limits many diabetes-related disturbances. Betaine therapy improves glucose tolerance and insulin action, which is strongly associated with changes in insulin-sensitive tissues, such as skeletal muscle, adipose tissue, and liver. Betaine supplementation positively affects multiple genes, which expression is dysregulated in diabetes. AMP-activated protein kinase is thought to play a central role in the mechanism underlying the anti-diabetic betaine action. Moreover, studies with animal models of type 2 diabetes have shown that betaine exerts anti-inflammatory and anti-oxidant effects, and also alleviates endoplasmic reticulum stress. These changes contribute to improved insulin sensitivity and better blood glucose clearance. The results of animal studies encourage the exploration of the therapeutic betaine efficacy in humans with type 2 diabetes.

High Fructose and High Fat Diet Impair Different Types of Memory through Oxidative Stress in a Sex- and Hormone-Dependent Manner

Metabolic syndrome (MetS) contributes to the spread of cardiovascular diseases, diabetes mellitus type 2, and neurodegenerative diseases. Evaluation of sex- and hormone-dependent changes in body weight, blood pressure, blood lipids, oxidative stress markers, and alterations in different types of memory in Sprague–Dawley rats fed with a high fat and high fructose (HFHF) diet were evaluated. After 12 weeks of feeding the male and female rats with HFHF, body weight gain, increase in blood pressure, and generation of dyslipidemia compared to the animals fed with chow diet were observed. Regarding memory, it was noted that gonadectomy reverted the effects of HFHF in the 24 h novel object recognition task and in spatial learning/memory analyzed through Morris water maze, males being more affected than females. Nevertheless, gonadectomy did not revert long-term memory impairment in the passive avoidance task induced by HFHF nor in male or female rats. On the other hand, sex-hormone–diet interaction was observed in the plasma concentration of malondialdehyde and nitric oxide. These results suggest that the changes observed in the memory and learning of MetS animals are sex- and hormone-dependent and correlate to an increase in oxidative stress.

Intergenerational effects of a paternal Western diet during adolescence on offspring gut microbiota, stress reactivity, and social behavior

The global consumption of highly processed, calorie-dense foods has contributed to an epidemic of overweight and obesity, along with negative consequences for metabolic dysfunction and disease susceptibility. As it becomes apparent that overweight and obesity have ripple effects through generations, understanding of the processes involved is required, in both maternal and paternal epigenetic inheritance. We focused on the patrilineal effects of a Western-style high-fat (21%) and high-sugar (34%) diet (WD) compared to control diet (CD) during adolescence and investigated F0 and F1 mice for physiological and behavioral changes. F0 males (fathers) showed increased body weight, impaired glycemic control, and decreased attractiveness to females. Paternal WD caused significant phenotypic changes in F1 offspring, including higher body weights of pups, increased Actinobacteria abundance in the gut microbiota (ascertained using 16S microbiome profiling), a food preference for WD pellets, increased male dominance and attractiveness to females, as well as decreased behavioral despair. These results collectively demonstrate the long-term intergenerational effects of a Western-style diet during paternal adolescence. The behavioral and physiological alterations in F1 offspring provide evidence of adaptive paternal programming via epigenetic inheritance. These findings have important implications for understanding paternally mediated intergenerational inheritance, and its relevance to offspring health and disease susceptibility.

Mechanisms Driving Palmitate-Mediated Neuronal Dysregulation in the Hypothalamus

The hypothalamus maintains whole-body homeostasis by integrating information from circulating hormones, nutrients and signaling molecules. Distinct neuronal subpopulations that express and secrete unique neuropeptides execute the individual functions of the hypothalamus, including, but not limited to, the regulation of energy homeostasis, reproduction and circadian rhythms. Alterations at the hypothalamic level can lead to a myriad of diseases, such as type 2 diabetes mellitus, obesity, and infertility. The excessive consumption of saturated fatty acids can induce neuroinflammation, endoplasmic reticulum stress, and resistance to peripheral signals, ultimately leading to hyperphagia, obesity, impaired reproductive function and disturbed circadian rhythms. This review focuses on the how the changes in the underlying molecular mechanisms caused by palmitate exposure, the most commonly consumed saturated fatty acid, and the potential involvement of microRNAs, a class of non-coding RNA molecules that regulate gene expression post-transcriptionally, can result in detrimental alterations in protein expression and content. Studying the involvement of microRNAs in hypothalamic function holds immense potential, as these molecular markers are quickly proving to be valuable tools in the diagnosis and treatment of metabolic disease.

Seaweed Dietary Fiber Sodium Alginate Suppresses the Migration of Colonic Inflammatory Monocytes and Diet-Induced Metabolic Syndrome via the Gut Microbiota

Metabolic syndrome (MetS) is a multifactorial chronic metabolic disorder that affects approximately one billion people worldwide. Recent studies have evaluated whether targeting the gut microbiota can prevent MetS. This study aimed to assess the ability of dietary fiber to control MetS by modulating gut microbiota composition. Sodium alginate (SA) is a seaweed-derived dietary fiber that suppresses high-fat diet (HFD)-induced MetS via an effect on the gut microbiota. We observed that SA supplementation significantly decreased body weight gain, cholesterol levels, and fat weight, while improving glucose tolerance in HFD-fed mice. SA changed the gut microbiota composition and significantly increased the abundance of Bacteroides. Antibiotic treatment completely abolished the suppressive effects of SA on MetS. Mechanistically, SA decreased the number of colonic inflammatory monocytes, which promote MetS development, in a gut microbiota-dependent manner. The abundance of Bacteroides was negatively correlated with that of inflammatory monocytes and positively correlated with the levels of several gut metabolites. The present study revealed a novel food function of SA in preventing HFD-induced MetS through its action on gut microbiota.

Recent Developments in Rodent Models of High-Fructose Diet-Induced Metabolic Syndrome: A Systematic Review

Metabolic syndrome (MetS) is the physiological clustering of hypertension, hyperglycemia, hyperinsulinemia, dyslipidemia, and insulin resistance. The MetS-related chronic illnesses encompass obesity, the cardiovascular system, renal operation, hepatic function, oncology, and mortality. To perform pre-clinical research, it is imperative that these symptoms be successfully induced and optimized in lower taxonomy. Therefore, novel and future applications for a disease model, if proven valid, can be extrapolated to humans. MetS model establishment is evaluated based on the significance of selected test parameters, paradigm shifts from new discoveries, and the accessibility of the latest technology or advanced methodologies. Ultimately, the outcome of animal studies should be advantageous for human clinical trials and solidify their position in advanced medicine for clinicians to treat and adapt to serious or specific medical situations. Rodents (Rattus norvegicus and Mus musculus) have been ideal models for mammalian studies since the 18th century and have been mapped extensively. This review compiles and compares studies published in the past five years between the multitude of rodent comparative models. The response factors, niche parameters, and replicability of diet protocols are also compiled and analyzed to offer insight into MetS-related disease-specific modelling.

Anti-Obesity and Lipid Lowering Activity of Bauhiniastatin-1 is Mediated Through PPAR-γ/AMPK Expressions in Diet-Induced Obese Rat Model

Objective: To evaluate the therapeutic efficacy and underlying molecular mechanisms of Bauhiniastatin-1 (BSTN1) to alleviate adiposity in diet-induced obese rodent model and in 3T3-L1 cells. Methods: BSTN1 was purified and confirmed through HPLC. In-vitro experiments such as MTT assay, Oil Red-O (ORO) stain, cellular lipid content, glycerol release and RT-PCR analysis were performed in 3T3-L1 cells in the presence and absence of BSTN1. In animal experiments, rats were divided into Group-I: normal pellet diet-fed, Group-II: HFD-fed, Groups-III, IV and V: HFD-fed BSTN1 (1.25, 2.5, and 5 mg/kg.b.wt./day/rat)-treated and Group-VI: HFD-fed Orlistat-treated. The rats were fed either normal diet or high fat diet (HFD) for 18 weeks and water ad-libitum. BSTN1 was orally administered from 13th week onwards to the selected HFD-fed groups. Body composition parameters, biochemical assays, histopathology examination and western blot analysis were performed to identify the predicted targets related to obesity. Molecular docking studies threw light on the binding interactions of BSTN1 against PPAR-γ, FAS and AMPK. Results: BSTN1 at 20 μM significantly (p < 0.001) inhibited adipocyte differentiation and lipid accumulation in 3T3-L1 cells. A conspicuous down-regulation in the mRNA expression levels of PPAR-γ, FAS and SREBP1 was observed but AMPK expression remained unchanged in BSTN1 treated 3T3-L1 cells. A substantial decrease in body weight gain, fat percent, total body fat, serum and liver lipid profile (except high-density lipoprotein), glucose, insulin and insulin resistance in BSTN1 treated rats was noticed in a dose dependent manner. In BSTN1 (5 mg/kg.b.wt.)-treated groups significantly (p < 0.01) elevated plasma adiponectin level but reduced leptin level as well as fall in serum AST and ALT were noticed. Further, the disturbed structural integrity and architecture of adipose and hepatic tissues due to high fat diet feeding were considerably recovered with BSTN1 treatment. Down-regulation in the protein expression level of PPAR-γ and activation of AMPK through phosphorylation was observed in BSTN1 treated rats than the untreated. Molecular docking studies revealed strong binding interactions of BSTN1 against PPAR-γ and AMPK and thus supported the experimental results. Conclusion: Taken together, the results suggest that BSTN1 could be a promising pharmacological molecule in the treatment of obesity and dyslipidemia.

The Effect of Cinnamaldehyde on iNOS Activity and NO-Induced Islet Insulin Secretion in High-Fat-Diet Rats

Introduction

Obesity and insulin resistance are associated with alterations in nitric oxide level and insulin secretion. Previous studies demonstrated that cinnamaldehyde (CNMA) improved islet insulin secretion and restored nitric oxide (NO) level, but its underlying mechanisms have not been investigated. This study aimed to investigate the effect of CNMA on inducible nitric oxide synthase (iNOS) activity and NO-induced islet insulin secretion in high-fat-diet (HFD) treated rats.

Materials and Methods

Forty male Wistar rats (12 weeks old) were randomly divided into four equal groups, namely, control, CNMA, HFD, and HFD + CNMA. Control and CNMA groups were treated with standard laboratory animals' diet, while HFD and HDF + CNMA groups were fed with an HFD diet enriched with 25% W/W tail fat for 16 weeks. CNMA was administrated orally (20 mg/kg body weight, daily) during the study period. Islet insulin secretion and the inducible NOS activity in the presence or absence of L-NAME (NO synthase inhibitor, 5 mmol/L) were evaluated.

Results

L-NAME-suppressed insulin secretion in control, HFD, and HFD + CNMA groups; however, in the CNMA group, it could not exhibit such effect (P < 0.01). Islets of HFD-treated animals showed significantly higher iNOS activity than controls. CNMA treatment significantly suppressed iNOS activities in CNMA and HFD + CNMA groups compared with control and HFD, respectively.

Conclusion

These results suggest that the beneficial effect of CNMA on insulin secretion might be due to its inhibitory effect on iNOS activity.

Short-term high fat diet alters genes associated with metabolic and vascular dysfunction during adolescence in rats: a pilot study

Background

Diet-induced metabolic dysfunction precedes multiple disease states including diabetes, heart disease, and vascular dysfunction. The critical role of the vasculature in disease progression is established, yet the details of how gene expression changes in early cardiovascular disease remain an enigma. The objective of the current pilot project was to evaluate whether a quantitative assessment of gene expression within the aorta of six-week old healthy male Sprague-Dawley rats compared to those exhibiting symptoms of metabolic dysfunction could reveal potential mediators of vascular dysfunction.

Methods

RNA was extracted from the aorta of eight rats from a larger experiment; four animals fed a high-fat diet (HFD) known to induce symptoms of metabolic dysfunction (hypertension, increased adiposity, fasting hyperglycemia) and four age-matched healthy animals fed a standard chow diet (CHOW). The bioinformatic workflow included Gene Ontology (GO) biological process enrichment and network analyses.

Results

The resulting network contained genes relevant to physiological processes including fat and protein metabolism, oxygen transport, hormone regulation, vascular regulation, thermoregulation, and circadian rhythm. The majority of differentially regulated genes were downregulated, including several associated with circadian clock function. In contrast, leptin and 3-hydroxy-3-methylglutaryl-CoA synthase 2 (Hmgcs2) were notably upregulated. Leptin is involved in several major energy balance signaling pathways and Hmgcs2 is a mitochondrial enzyme that catalyzes the first reaction of ketogenesis.

Conclusion

Together, these data describe changes in gene expression within the aortic wall of HFD rats with early metabolic dysfunction and highlight potential pathways and signaling intermediates that may impact the development of early vascular dysfunction.

Lipoic Acid Exacerbates Oxidative Stress and Lipid Accumulation in the Liver of Wistar Rats Fed a Hypercaloric Choline-Deficient Diet

Non-alcoholic fatty liver disease (NAFLD) is currently estimated as the most prevalent chronic liver disease in all age groups. An increasing body of evidence obtained in experimental and clinical data indicates that oxidative stress is the most important pathogenic factor in the development of NAFLD. The study aimed to investigate the impact of α-lipoic acid (LA), widely used as an antioxidant, on the effects of a hypercaloric choline-deficient diet. Male Wistar rats were divided into three groups: control diet (C); hypercaloric choline-deficient diet (HCCD), and hypercaloric choline-deficient diet with α-lipoic acid (HCCD+LA). Supplementation of HCCD with LA for eight weeks led to a decrease in visceral adipose tissue/body weight ratio, the activity of liver glutathione peroxidase and paraoxonase-1, plasma, and liver total antioxidant activity, as well as an increase in liver/body weight ratio, liver total lipid and triglyceride content, and liver transaminase activities compared to the HCCD group without LA. In conclusion, our study shows that α-lipoic acid detains obesity development but exacerbates the severity of diet-induced oxidative stress and lipid accumulation in the liver of male Wistar rats fed a hypercaloric choline-deficient diet.

Motor learning impairment in rats under a high sucrose diet

Motor learning skills are reliable indicators of behavioral acquisition and cognitive disorders. The ease with which learning skills are measured disparities the complexity of the interpretation concerning neural plasticity. Conversely, a wealth of information regarding metabolic derangements has long been reported with direct connection to high sucrose diets. However, the impact of excessive sucrose consumption on undergoing cognitive processes has been only scarcely addressed up to now. Therefore, the goal of this work was to describe the associative relationship between high sucrose consumption and changes in motor learning skills acquisition. Motor learning impairments conditioned by central alterations are hypothesized. Rotarod, elevated plus-maze and open field trials, along with metabolic and pro-inflammatory biomarkers tests in Wistar rats under a high sucrose treatment, were performed. Motor learning impairment in high sucrose diet-treated rats was found while spontaneous locomotor activity remained unchanged. Even though, no anxiety-like behavior under high sucrose diet-treatment was observed. Consistently, the worst outcome in the glucose tolerance test was developed, the worst motor learning performance was observed. Furthermore, insulin resistance correlated positively with a pro-inflammatory state and a decreased latency to fall in the rotarod test. Indeed, C-reactive protein and tumor necrosis factor-α serum levels, along with the homeostasis model assessment of insulin resistance (HOMA-IR), significantly increased in motor learning impairment. Together, these results support behavioral, metabolic and pro-inflammatory changes associated with deleterious changes in central nervous system likely involving crucial motor learning structures. Underlying pro-inflammatory-triggered processes may explain cognitive disorders in advanced states of metabolic derangements.

Polyphenols and Fish Oils for Improving Metabolic Health: A Revision of the Recent Evidence for Their Combined Nutraceutical Effects

Polyphenols and omega-3 polyunsaturated fatty acids from fish oils, i.e., eicosapentaenoic and docosahexaenoic acids, are well-recognized nutraceuticals, and their single antioxidant and anti-inflammatory properties have been demonstrated in several studies found in the literature. It has been reported that the combination of these nutraceuticals can lead to three-fold increases in glutathione peroxidase activity, two-fold increases in plasma antioxidant capacity, decreases of 50-100% in lipid peroxidation, protein carbonylation, and urinary 8-isoprotanes, as well as 50-200% attenuation of common inflammation biomarkers, among other effects, as compared to their individual capacities. Therefore, the adequate combination of those bioactive food compounds and their single properties should offer a powerful tool for the design of successfully nutritional interventions for the prevention and palliation of a plethora of human metabolic diseases, frequently diet-induced, whose etiology and progression are characterized by redox homeostasis disturbances and a low-grade of chronic inflammation. However, the certain mechanisms behind their biological activities, in vivo interaction (both between them and other food compounds), and their optimal doses and consumption are not well-known yet. Therefore, we review here the recent evidence accumulated during the last decade about the cooperative action between polyphenols and fish oils against diet-related metabolic alterations, focusing on the mechanisms and pathways described and the effects reported. The final objective is to provide useful information for strategies for personalized nutrition based on these nutraceuticals.

Alzheimer's Disease and Diabetes: Role of Diet, Microbiota and Inflammation in Preclinical Models

Alzheimer's disease (AD) is the most common cause of dementia. Epidemiological studies show the association between AD and type 2 diabetes (T2DM), although the mechanisms are not fully understood. Dietary habits and lifestyle, that are risk factors in both diseases, strongly modulate gut microbiota composition. Also, the brain-gut axis plays a relevant role in AD, diabetes and inflammation, through products of bacterial metabolism, like short-chain fatty acids. We provide a comprehensive review of current literature on the relation between dysbiosis, altered inflammatory cytokines profile and microglia in preclinical models of AD, T2DM and models that reproduce both diseases as commonly observed in the clinic. Increased proinflammatory cytokines, such as IL-1β and TNF-α, are widely detected. Microbiome analysis shows alterations in Actinobacteria, Bacteroidetes or Firmicutes phyla, among others. Altered α- and β-diversity is observed in mice depending on genotype, gender and age; therefore, alterations in bacteria taxa highly depend on the models and approaches. We also review the use of pre- and probiotic supplements, that by favoring a healthy microbiome ameliorate AD and T2DM pathologies. Whereas extensive studies have been carried out, further research would be necessary to fully understand the relation between diet, microbiome and inflammation in AD and T2DM.

The cafeteria diet: A standardized protocol and its effects on behavior

Obesity is a major health risk, with junk food consumption playing a central role in weight gain, because of its high palatability and high-energy nutrients. The Cafeteria (CAF) diet model for animal experiments consists of the same tasty but unhealthy food products that people eat (e.g. hot dogs and muffins), and considers variety, novelty and secondary food features, such as smell and texture. This model, therefore, mimics human eating patterns better than other models. In this paper, we systematically review studies that have used a CAF diet in behavioral experiments and propose a standardized CAF diet protocol. The proposed diet is ad libitum and voluntary; combines different textures, nutrients and tastes, including salty and sweet products; and it is rotated and varied. Our summary of the behavioral effects of CAF diet show that it alters meal patterns, reduces the hedonic value of other rewards, and tends to reduce stress and spatial memory. So far, no clear effects of CAF diet were found on locomotor activity, impulsivity, coping and social behavior.

Protective Role of Picralima nitida Seed Extract in High-Fat High-Fructose-Fed Rats

Picralima nitida is a therapeutic herb used in ethnomedicine for the management of several disease conditions including diabetes. This study examined the potential palliative effect of aqueous seed extract of Picralima nitida (APN) on dyslipidemia, hyperglycemia, oxidative stress, insulin resistance, and the expression of some metabolic genes in high-fat high-fructose-fed rats. Experimental rats (2 months old) were fed a control diet or a high-fat diet with 25% fructose (HFHF diet) in their drinking water for nine weeks. APN was administered orally during the last four weeks. Anthropometric and antioxidant parameters, lipid profile, plasma glucose, and insulin levels and the relative expression of some metabolic genes were assessed. APN caused a significant decrease (P < 0.05) in weight gained, body mass index, insulin resistance, plasma glucose, and insulin levels. High-density lipoprotein cholesterol level was significantly increased (P < 0.05), while triacylglycerol, cholesterol, low-density lipoprotein, cardiac index, atherogenic index, coronary artery index, and malondialdehyde levels in plasma and liver samples were also significantly decreased (P < 0.05) by APN at all experimental doses when compared to the group fed with an HFHF diet only. APN also significantly (P < 0.05) upregulated the relative expression of glucokinase, carnitine palmitoyltransferase-1 (CPT-1), and leptin at 400 mg/kg body weight when compared to the group fed with an HFHF diet only. This study showed that APN alleviated dyslipidemia, hyperglycemia, and oxidant effect associated with the intake of a high-fat high-fructose diet.