An Intestinal FXR Agonist Mitigates Dysbiosis, Intestinal Tight Junctions, and Inflammation in High-Fat Diet-Fed Mice.

SCOPE: To analyze the effects of fexaramine (FEX), as an intestinal FXR agonist, on the modulation of the intestinal microbiota and ileum of mice fed a high-fat (HF) diet. METHODS AND RESULTS: Three-month-old C57Bl/6 male mice are divided into two groups and received a control (C, 10% of energy from lipids) or HF (50% of energy from lipids) diet for 12 weeks. They are subdivided into the C, C + FEX, HF, and HF + FEX groups. FEX is administered (FEX-5 mg kg-1 ) via orogastric gavage for three weeks. Body mass (BM), glucose metabolism, qPCR 16S rRNA gene expression, and ileum gene expression, bile acids (BAs), tight junctions (TJs), and incretin are analyzed. FEX reduces BM and glucose intolerance, reduces plasma lipid concentrations and the Firmicutes/Bacteroidetes ratio, increases the Lactobacillus sp. and Prevotella sp. abundance, and reduces the Escherichia coli abundance. Consequently, the ileal gene expression of Fxr-Fgf15, Tgr5-Glp1, and Cldn-Ocldn-Zo1 is increased, and Tlr4-Il6-Il1beta is decreased. CONCLUSION: FEX stimulates intestinal FXR and improves dysbiosis, intestinal TJs, and the release of incretins, mitigating glucose intolerance and BM increases induced by an HF diet. However, FEX results in glucose intolerance, insulin resistance, and reduces intestinal TJs in a control group, thus demonstrating limitations to this dietary model.

Exercise prevents obesity by reducing gut-derived inflammatory signals to brown adipocytes in mice.

Gut dysbiosis impairs nonshivering thermogenesis (NST) in obesity. The antiobesogenic effects of exercise training might involve the modulation of gut microbiota and its inflammatory signals to the brown adipose tissue (BAT). This study evaluated whether high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) prevent overweight through reduced gut-derived inflammatory signals to BAT in high-fat-fed mice. Sixty male C57BL/6 mice (3 months old) comprised six experimental groups: control (C) diet group, C diet + HIIT (C-HIIT) group, C diet + MICT (C-MICT) group, high-fat (HF) diet group, HF diet + HIIT (HF-HIIT) group, and HF diet + MICT (HF-MICT) group. The protocols lasted for 10 weeks. HIIT and MICT restored body mass, mitigated glucose intolerance, and prevented hyperinsulinemia in HF-trained groups. A chronic HF diet caused dysbiosis, but HIIT and MICT prevented gut dysbiosis and preserved tight junction (TJ) gene expression. HF-HIIT and HF-MICT groups exhibited a similar pattern of goblet cell distribution, agreeing with the decreased plasma lipopolysaccharide concentrations and interscapular BAT (iBAT) Lbp-Cd14-Tlr4 expression. The lowered Nlrp3 and Il1ß in the HF-HITT and HF-MICT groups complied with iBAT thermogenic capacity maintenance. This study shows reliable evidence that HIIT and MICT prevented overweight by restoring the diversity of the gut microbiota phyla and TJ gene expression, thereby reducing inflammatory signals to brown adipocytes with preserved thermogenic capacity. Both exercise modalities prevented overweight, but HIIT rescued Zo-1 and Jam-a gene expression, exerting more potent anti-inflammatory effects than MICT (reduced LPS concentrations), providing a sustained increase in thermogenesis with 78% less distance traveled.

AMPK/mTOR pathway significance in healthy liver and non-alcoholic fatty liver disease and its progression.

Obesity is related to several organs, but the liver is particularly affected. Adenosine monophosphate-activated protein kinase (AMPK) is a cellular energy sensor and regulator of liver lipid dysfunction and glucose metabolism. The mechanistic target of rapamycin (mTOR) is a protein kinase regulating cell growth, survival, metabolism, and immunity. Together, these pathways are involved in obesity, insulin resistance, non-alcoholic fatty liver disease (NAFLD) and its progression, and autophagy. During energy demand, liver kinase B (LKB) phosphorylation helps activate the AMPK/mTOR pathways. Likewise, the protein forkhead box O family (FOXO) negatively regulates adipogenesis by binding to the promoter sites of peroxisome proliferator-activated receptor-gamma coactivator 1-alpha, initiating adipogenesis. In addition, acetyl-CoA carboxylase, which regulates de novo lipogenesis, is linked to LKB and FOXO in developing NAFLD. The kinase complex, consisting of Unc-51-like autophagy-activating kinase 1 or 2 (ULK1, ULK2) by stimulating autophagy, and eliminating fat droplets in NAFLD, is regulated by mTORC1 and negatively regulated by AMPK that suppresses liver lipogenesis and increases fatty acid oxidation. Also, ULK1 is essential for initiating phagophore formation, establishing macrophagy, and generating autophagosomes. The selective breakdown of lipid droplets through macroautophagy, or macrolipophagy, occurs on a cellular energy level using free fatty acids. In addition, mTORC1 promotes lipogenesis by activating sterol regulatory element-binding protein. Finding new components and novel regulatory modes in signaling is significant for a better understanding of the AMPK/mTOR pathways, potentially facilitating the development of future diagnostic and therapeutic strategies for NAFLD and its progression to non-alcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma.

Pancreatic islet remodeling in cotadutide-treated obese mice.

Obesity and type 2 diabetes mellitus (T2DM) cause morphofunctional alterations in pancreatic islet alpha and beta cells. Therefore, we hypothesize that the new GLP-1/Glucagon receptor dual agonist cotadutide may benefit islet cell arrangement and function. Twelve-week-old C57BL/6 male mice were fed a control diet (C, 10 % kJ fat) or a high-fat diet (HF, 50 % kJ fat) for ten weeks. Then, the animals were divided into four groups for an additional 30 days and daily treated with subcutaneous cotadutide (30 nmol/kg) or vehicle: C, CC (control+cotadutide), HF, and HFC (high-fat+cotadutide). Cotadutide led to weight loss and reduced insulin resistance in the HFC group, increasing insulin receptor substrate 1 and solute carrier family 2 gene expressions in isolated islets. Also, cotadutide enhanced transcriptional factors related to islet cell transdifferentiation, decreasing aristaless-related homeobox and increasing the paired box 4 and 6, pancreatic and duodenal homeobox 1, v-maf musculoaponeurotic fibrosarcoma oncogene family protein A, neurogenin 3, and neurogenic differentiation 1. In addition, cotadutide improved the proliferating cell nuclear antigen, NK6 homeobox 1, B cell leukemia/lymphoma 2, but lessening caspase 3. Furthermore, cotadutide mitigated the endoplasmic reticulum (ER) stress-responsive genes, reducing transcription factor 4, DNA-damage-inducible transcript 3, and growth arrest and DNA-damage-inducible 45. In conclusion, our data demonstrated significant beneficial actions of cotadutide in DIO mice, such as weight loss, glycemic control, and insulin resistance improvement. In addition, cotadutide counteracted the pathological adaptive cellular arrangement of the pancreatic islet in obese mice, improving the markers of the transdifferentiating pathway, proliferation, apoptosis, and ER stress.

High-intensity interval training (treadmill) effects in myokines and endoplasmic reticulum stress of calf muscles in obese mice / Efectos del entrenamiento interválico de alta intensidad (trotadora) en miocinas y estrés del retículo endoplasmático de los músculos surales en ratones obesos

SUMMARY: Obesity is commonly associated with chronic tissue inflammation and skeletal muscle dysfunction. The study aimed to investigate the effects of High-Intensity Interval training (HIIT) on myokines and endoplasmic reticulum (ER) stress of diet- induced obese (DIO) mice. Three-month-old C57BL/6 male mice were fed a control (C) diet (n=20) or a high-fat (HF) diet (n=20) for 16 weeks. Then, half of the groups underwent HIIT (treadmill running) for an additional four weeks. HIIT increased calf muscles' contribution to BW (+24 %) and reduced weight gain in HF/HIIT than in HF (-120 %). Intramuscular fat accumulation was observed in HF and HF/ HIIT. Peak velocity was higher in HF/HIIT compared to HF (+26 %). Plasma insulin did not change, but glycemia was lower in HF/HIIT than in HF (-30 %). Fndc5 (+418 %) and Irisin (+72 %) were higher in HF/HIIT than in HF. Muscle Fgf21 was higher in HF/HIIT compared to HF (+30 %). In addition, NfKb (-53 %) and Tnfa (-63 %) were lower in HF/HIIT than in HF. However, Il1b (-86 %), Il6 (- 48 %), Il7 (-76 %), and Il15 (-21 %) were lower in HF/HIIT than in HF. Finally, HIIT reduced ER stress in HF/HIIT compared to HF: Atf4, -61 %; Chop, -61 %; Gadd45, -95 %. In conclusion, HIIT leads to weight loss and avoids muscle depletion. HIIT improves blood glucose, Irisin-Fndc5, and peak velocity. In addition, HIIT mitigates muscle inflammation and ER stress.

La obesidad es asociada comúnmente con inflamación tisular crónica y disfunción del músculo esquelético. El estudio tuvo como objetivo investigar los efectos del entrenamiento de intervalos de alta intensidad (HIIT) en las mioquinas y el estrés del retículo endoplásmico (ER) de ratones obesos inducidos por dieta (DIO). Se alimentó a ratones macho C57BL/6 de tres meses de edad con una dieta control (C) (n=20) o una dieta rica en grasas (HF) (n=20) durante 16 semanas. Luego, la mitad de los grupos se sometieron a HIIT (carrera en una trotadora) durante cuatro semanas más. HIIT aumentó la contribución de los músculos de la pantorrilla al BW (+24 %) y redujo el aumento de peso en HF/HIIT en HF (-120 %). Se observó acumulación de grasa intramuscular en HF y HF/HIIT. La velocidad máxima fue mayor en HF/HIIT en comparación con HF (+26 %). La insulina plasmática no cambió, pero la glucemia fue menor en HF/HIIT que en HF (-30 %). Fndc5 (+418 %) e Irisin (+72 %) fueron mayores en HF/HIIT que en HF. El Fgf21 muscular fue mayor en HF/ HIIT en comparación con HF (+30 %). Además, NfKb (-53 %) y Tnfa (-63 %) fueron menores en HF/HIIT que en HF. Sin embar- go, Il1b (-86 %), Il6 (-48 %), Il7 (-76 %) e Il15 (-21 %) fueron más bajos en HF/HIIT que en HF. Finalmente, HIIT redujo el estrés de RE en HF/HIIT en comparación con HF: Atf4, -61 %; Picar, - 61 %; Gadd45, -95 %. En conclusión, HIIT conduce a la pérdida de peso y evita el agotamiento muscular. HIIT mejora la glucosa en sangre, Irisin-Fndc5 y la velocidad máxima. Además, HIIT mitiga la inflamación muscular y el estrés ER.

Cotadutide effect in liver and adipose tissue in obese mice.

Obesity, adipose tissue inflammation, and nonalcoholic fatty liver disease (NAFLD) are associated with insulin resistance and type 2 diabetes (T2D). Cotadutide is a dual agonist GLP-1/glucagon, currently in a preclinical study phase 2 that presents an anti-obesity effect. Diet-induced obese (DIO) C57BL/6 mice were treated for 4 weeks with cotadutide (30 nm/kg once a day at 14:00 h). The study focused on epididymal white adipose tissue (eWAT), liver (NAFLD), inflammation, lipid metabolism, AMP-activated protein kinase (AMPK)/mechanistic target of rapamycin (mTOR) pathways, and the endoplasmic reticulum (ER) stress. As a result, cotadutide controlled weight gain, glucose intolerance, and insulin resistance and showed beneficial effects on plasma markers in DIO mice (triacylglycerol, total cholesterol, alanine aminotransferase, and aspartate aminotransferase, leptin, adiponectin, monocyte chemoattractant protein-1, resistin, interleukin-6, tumor necrosis factor-alpha). Also, cotadutide lessened liver fat accumulation, eWAT proinflammatory markers, and ER stress. In addition, cotadutide improved lipid metabolism genes in eWAT, fatty acid synthase, peroxisome proliferator-activated receptor gamma and mitigates adipocyte hypertrophy and apoptosis. Furthermore, the effects of cotadutide were related to liver AMPK/mTOR pathway and ER stress. In conclusion, cotadutide induces weight loss and treats glucose intolerance and insulin resistance in DIO mice. In addition, cotadutide shows beneficial effects on liver lipid metabolism, mitigating steatosis, inflammation, and ER stress. Besides, in adipocytes, cotadutide decreases hypertrophy and reduces apoptosis. These actions rescuing the AMPK and mTOR pathway, improving lipid metabolism, and lessening NAFLD, inflammation, and ER stress in both eWAT and liver of DIO mice indicate cotadutide as a potentially new pharmacological treatment for T2D and associated obesity.

Brown adipose tissue as an endocrine organ: updates on the emerging role of batokines.

Brown adipose tissue (BAT) remains active in adults, oxidizing fatty acids or glucose and releasing energy in the form of heat. Brown adipocytes and enhanced thermogenesis are targets for treating obesity and its comorbidities. BAT shows high synthesis activity and secretes several signaling molecules. The brown adipokines, or batokines, take action in an autocrine, paracrine, and endocrine manner. Batokines have a role in the homeostasis of the cardiovascular system, central nervous system, white adipose tissue, liver, and skeletal muscle and exert beneficial effects on BAT. The systemic function of batokines gives BAT an endocrine organ profile. Besides, the batokines Fibroblast Growth Factor-21, Vascular Endothelial Growth Factor A, Bone Morphogenetic Protein 8, Neuregulin 4, Myostatin, and Interleukin-6 emerge as targets to treat obesity and its comorbidities, deserving attention. This review outlines the role of six emerging batokines on BAT and their cross-talk with other organs, focusing on their physiological significance and diet-induced changes.

The obesity and nonalcoholic fatty liver disease mouse model revisited: Liver oxidative stress, hepatocyte apoptosis, and proliferation.

The study revisited the diet-induced obesity (DIO) mice and the nonalcoholic fatty liver disease (NAFLD) pathogenesis to serve as a translational model. Hepatic beta-oxidation pathways, lipogenesis, oxidative stress, hepatocyte apoptosis, and proliferation were investigated in obese mice. Three-month-old male mice were divided according to their diet for fifteen weeks, the control diet (C group, containing 10% energy from fat) and the high-fat diet (HF group, containing 50% energy from fat). Body weight (BW), liver mass, and steatosis were higher in the HF group than in the C group. Also, gene expression related to beta-oxidation and lipogenesis showed an adverse profile, and insulin and glucose signaling pathways were impaired in the HF group compared to the C group. As a result, steatosis was prevalent in the HF group but not in the C group. Furthermore, the pathways that generate NAFLD were negatively modulated by oxidative stress in the HF animals than in the C ones. The caspase 3 immunolabeled HF hepatocytes with increased gene and protein expressions related to apoptosis while proliferating cell nuclear antigen labeled C hepatocytes. In conclusion, the findings in the DIO mouse model reproduce the NAFLD profile relative to the human NAFLD's apoptosis, insulin signaling, lipogenesis, beta-oxidation, and oxidative stress. Therefore, the model is adequate for a translational perspective's morphological, biochemical, and molecular research on NAFLD.

The morphological challenge in determining nuclear size and shape in anatomopathological neoplasia analysis / El desafío morfológico en la determinación del tamaño y forma nuclear en el análisis anatomopatológico de neoplasias

SUMMARY: From 1984 stereology was added to unbiased methods and procedures, i.e., counts became more reliable studying morphological images in a random and uniform isotropic way. Therefore, the orientation and sectioning methods adapted to stereological quantification are essential. A critical quantitative subject in practical pathology concerns diagnosing and classifying neoplasias. Pathologists evaluated different types of tumors by determining the nuclear roundness factor (NRF). NRF is calculated by the ratio between the nuclear radius obtained from the area and the perimeter. However, NRF is biased data because it depends on the sectioning orientation, nuclei shape, and section thickness. The stereology proposed an unbiased alternative to assess the nucleus from tumor cells, counteracting NRF quantitatively. Therefore, the volume-weighted mean nuclear volume has been used to prognostic tumors in several organs. In urology, this was used, for example, to study primary carcinoma of the bladder, renal and prostatic carcinomas.

RESUMEN: A partir de 1984 se agregó la estereología a los métodos y procedimientos sin distorción, es decir, los conteos se volvieron más confiables al estudiar imágenes morfológicas de forma aleatoria e isotrópica uniforme. Por tanto, los métodos de orientación y seccionamiento adaptados a la cuantificación estereológica son fundamentales. Un tema cuantitativo crítico en la patología práctica se refiere al diagnóstico y clasificación de las neoplasias. Los patólogos evaluaron diferentes tipos de tumores determinando el factor de redondez nuclear (NRF). NRF se calcula por la relación entre el radio nuclear obtenido del área y el perímetro. Sin embargo, NRF son datos distorsionados debido a que dependen de la orientación de la sección, la forma de los núcleos y el grosor de la sección. La estereología propuso una alternativa imparcial para evaluar el núcleo de las células tumorales, contrarrestando cuantitativamente el NRF. Por lo tanto, el volumen nuclear medio ponderado se ha utilizado para pronosticar tumores en varios órganos. En urología, esto se utilizó, por ejemplo, para estudiar el carcinoma primario de vejiga, carcinomas renales y prostáticos.

The mTORC1/AMPK pathway plays a role in the beneficial effects of semaglutide (GLP-1 receptor agonist) on the liver of obese mice.

PURPOSE: The liver regulates lipid metabolism. Decreasing mTOR (mechanistic target of rapamycin complex 1) and enhancing AMPK (AMP-activated protein kinase) help degrade hepatic diet-induced accumulated lipids. Therefore, the glucagon-like peptide type 1 receptor agonist (GLP-1) is indicated to treat obesity-related liver metabolic alterations. Then, we investigated the effects of semaglutide (recent GLP-1) by analyzing the liver mTORC1/AMPK pathway genes in obese mice. BASIC PROCEDURES: C57BL/6 male mice were separated into two groups and submitted for 16 weeks of obesity induction. Then they were treated for an additional four weeks with semaglutide (subcutaneous, 40 µg/kg once every three days). The groups formed were: C, control group; CS, control group plus semaglutide; HF, high-fat group; HFS, high-fat group plus semaglutide. Next, the livers were dissected, and rapidly fragments of all lobes were kept and frozen at -80° C for analysis (RT-qPCR). MAIN FINDINGS: Liver markers for the mTOR pathway associated with anabolism and lipogenesis de novo were increased in the HF group compared to the C group but comparatively attenuated by semaglutide. Also, liver markers for the AMPK pathway, which regulates chemical pathways involving the cell's primary energy source, were impaired in the HF group than in the C group but partly restored by semaglutide. CONCLUSION: the mTOR pathway was attenuated, and the insulin signaling and the AMPK pathway were enhanced by semaglutide, ameliorating the liver gene expressions related to the metabolism of obese mice. These findings are promising in delaying the progression of nonalcoholic fatty liver disease.

Intermittent fasting, high-intensity interval training, or a combination of both have beneficial effects in obese mice with nonalcoholic fatty liver disease.

Intermittent fasting (IF) and high-intensity interval training (HIIT) are procedures that might mitigate the effects of nonalcoholic fatty liver disease. Two groups of 3-month-old C57BL/6 male mice were fed for 16 weeks with a control (C) or high-fat (HF) diet. In the last 4 weeks of the study, IF, HIIT, and IF/HIIT were implemented. Obese HF animals showed liver fat accumulation with macro-, and micro-vesicular steatosis and inflammatory infiltrate. IF and HIIT successfully reduced liver steatosis in the HF-derived groups. IF, HIIT, and IF/HIIT were beneficial in improving glucose metabolism in both C-derived and HF-derived groups. High levels observed in plasmatic and liver levels of total cholesterol and triacylglycerol in the HF group compared to the C group were mitigated by IF, HIIT, and IF/HIIT. IF decreased adiponectin and increased leptin and insulin in the HF group. HIIT improved adiponectin and leptin. IF chances liver gene expressions: increased interleukin-6 (IL-6) in the C IF group, reduced IL-6, and PAI-1 in the HF group. IF/HIIT reduced IL-6, MCP-1, and PAI-1. IF and HIIT enhanced hepatic beta-oxidation. However, lipogenesis was reduced by IF and HIIT in the HF-derived groups. In conclusion, IF and HIIT benefit weight loss, hormones, glucose tolerance/insulin resistance, liver steatosis/inflammation, fatty acid oxidation, and lipogenesis. Furthermore, the IF groups showed beneficial effects more often and intensely than HIIT ones. The IF/HIIT combination was slightly more efficient than IF, indicating that IF is the primary intervening factor benefiting the obese mouse liver.

A PPAR-alpha agonist and DPP-4 inhibitor mitigate adipocyte dysfunction in obese mice.

Obesity causes white and brown adipocyte dysfunction, reducing browning and stimulating whitening. Drugs that tackle adipocyte dysfunction through thermogenesis stimulation could be used to treat obesity. This study sought to address whether a combination of the PPAR-alpha agonist (WY14643) and DPP4i (linagliptin) potentiates browning and mitigates adipose tissue dysfunction, emphasizing the pathways related to browning induction and the underlying thermogenesis in high-fat-fed mice. Adult male C57BL/6 mice were randomly assigned to receive a control diet (C, 10% lipids) or a high-fat diet (HF, 50% lipids) for 12 weeks. Experiment 1 aimed to evaluate whether 5 weeks of combined therapy was able to potentiate browning using a five-group design: C, HF, HFW (monotherapy with WY14643, 2.5 mg/kg body mass), HFL (monotherapy with linagliptin, 15 mg/kg body mass), and HFC (a combination of both drugs). Experiment 2 further addressed the pathways involved in browning maximization using a four-group study design: C, CC (C diet plus the drug combination), HF, and HFC (HF diet plus the drug combination). The HF group showed overweight, oral glucose intolerance, sWAT adipocyte hypertrophy, and reduced numerical density of nuclei per area of BAT confirming whitening. Only the combined treatment normalized these parameters in addition to body temperature increase, browning induction, and whitening rescue. The high expression of thermogenic marker genes parallel to reduced expression of inflammatory and endoplasmic reticulum stress genes mediated the beneficial findings. Hence, the PPAR-alpha agonist and DPP-4i combination is a promising target for obesity control by inducing functional brown adipocytes, browning of sWAT, and enhanced adaptive thermogenesis.

Progressive brown adipocyte dysfunction: Whitening and impaired nonshivering thermogenesis as long-term obesity complications.

Chronic obesity damages the cytoarchitecture of brown adipose tissue (BAT), leading to whitening of brown adipocytes and impaired thermogenesis, characterizing BAT dysfunction. Understanding the pathways of whitening progression can bring new targets to counter obesity. This study aimed to evaluate the chronic effect (12, 16, and 20 weeks) of a high-fat diet (50% energy as fat) upon energy expenditure, thermogenic markers, and pathways involved in BAT whitening in C57BL/6J mice. Sixty adult male mice comprised six nutritional groups, where the letters refer to the diet type (control, C or high-fat, HF), and the numbers refer to the period (in weeks) of diet administration: C12, HF12, C16, HF16, C20, and HF20. After sacrifice, biochemical, molecular, and stereological analyses addressed the outcomes. The HF groups had overweight, oral glucose intolerance, and hyperleptinemia, resulting in progressive whitening of BAT and decreased numerical density of nuclei per area of tissue compared to age-matched control groups. In addition, the whitening maximization was related to altered batokines gene expression, decreased nonshivering thermogenesis, and body temperature, resulting in low energy expenditure. The HF20 group showed enlarged adipocytes with stable and dysfunctional lipid droplets, followed by inflammation and ER stress. In conclusion, chronic HF diet intake caused time-dependent maximization of whitening with defective nonshivering thermogenesis. Long-term BAT dysfunction includes down-regulated vascularization markers, upregulated inflammasome activation, and ER stress markers.

Pancreatic islet cells disarray, apoptosis, and proliferation in obese mice. The role of Semaglutide treatment.

There are significant injuries of pancreatic islets due to obesity and insulin resistance. Therefore, GLP-1 receptor agonists like Semaglutide might benefit the islet structural remodeling and its endocrine function in diet-induced obese mice. One-month-old male C57BL/6 mice were allotted into two dietary groups (n = 60/group) and fed for 16 weeks a control diet (C) or a high‒fat diet (HF). Then, for an additional four weeks, the main groups were resampled to include treatment (Semaglutide, S, 40 µg/kg), or paired feed with the treated group (PF), totaling six groups (n = 20/group): C, CS, CPF, HF, HFS, HFPF. Biochemistry, stereology, immunohistochemistry/immunofluorescence, confocal microscopy, and RT-qPCR were used in the study. The mouse model reproduced metabolism and bodily changes due to diet-induced obesity. Pancreatic islet hypertrophy was observed with alpha- and beta-cell remodeling, cell disarray, and apoptosis. Semaglutide increased islet cell proliferation and recovered islet size and alpha- and beta-cell masses. The changes include recovery of glucose and hormone levels, reduction of pro-inflammatory markers, improvement of pancreatic duodenal homeobox 1 (PDX-1), glucose transporter 2 (GLUT-2), v-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MAF-A), and peroxisome proliferator-activated receptors (PPAR) -gamma. In conclusion, damage to the pancreatic islet caused by insulin resistance and the attempt to adapt the islet of obese mice involved different pathways, especially the pro-inflammatory pathway, PDX1, and PPAR-alpha and gamma. Semaglutide showed beneficial effects on these pathways, reducing the lesion on the islet. However, the weight loss influence of Semaglutide was of little relevance in the pancreatic islet.

The current significance and prospects for the use of dual receptor agonism GLP-1/Glucagon.

The therapeutic arsenal for treating type 2 diabetes mellitus (T2DM) has been enriched recently with the inclusion of type 1 glucagon-like peptide (GLP-1). GLP-1 receptor agonists (RA) secondarily reduce appetite, decrease gastric emptying, and reduce body weight. This effect has been used to treat overweight/obesity, especially with comorbidities associated with T2DM. However, the first formulations and adverse effects gradually gave way to new formulations with fewer unpleasant effects and a more extended period of action (weekly subcutaneous administration and even oral administration), which improved the acceptance and adherence to the treatment. Therefore, titration of GLP-1RA should be done gradually. Furthermore, when side effects are consistent and intolerable after weeks/months of titration, a lower dose or a combination of antidiabetic therapies should be implemented, avoiding treatment interruption. The effort to produce increasingly powerful molecules with fewer side effects is the driving force behind the pharmaceutical industry. The unimolecular dual agonism GLP-1RA plus glucagon receptor agonism (GRA) represents an updated pharmacological indication for controlling blood glucose levels in treating T2DM and its comorbidities, showing better effects with less adverse impact than mono GLP-1RA. There are currently different proposals in this way by different laboratories. Nevertheless, the experimental results are promising and show that soon, we will have the contribution of new drugs for the treatment of T2DM.

Obese mice weight loss role on nonalcoholic fatty liver disease and endoplasmic reticulum stress treated by a GLP-1 receptor agonist.

BACKGROUND/OBJECTIVES: The weight loss following Semaglutide treatment, a GLP-1 receptor agonist, might be responsible for some effects observed on the nonalcoholic fatty liver disease of obese mice. SUBJECTS/METHODS: Two groups of C57BL/6 male mice (n = 30/group) were fed the diets Control (C) or high-fat (HF) for 16 weeks. Then, separated into six new groups for an additional four weeks (n = 10/group) and treated with Semaglutide (S, 40 µg/kg) or paired feeding (PF) with S groups (C; C-S; C-PF; HF; HF-S; HF-PF). RESULTS: Semaglutide reduced energy consumption leading to weight loss. Simultaneously it improved glucose intolerance, glycated hemoglobin, insulin resistance/sensitivity, plasma lipids, and gastric inhibitory polypeptide. Semaglutide and paired feeding mitigated liver steatosis and adipose differentiation-related protein (Plin2) expression. Semaglutide also improved hormones and adipokines, reduced lipogenesis and inflammation, and increased beta-oxidation. Semaglutide lessened liver glucose uptake and endoplasmic reticulum (ER) stress. Among the 14 genes analyzed, 13 were modified by Semaglutide (93 %, six genes were changed exclusively by Semaglutide, and seven other genes were affected by the combination of Semaglutide and paired feeding). In seven genes, the paired diet showed no effect (50% of the genes tested). No marker was affected exclusively by paired feeding. CONCLUSIONS: Semaglutide and the consequent weight loss reduced obese mice liver inflammation, insulin resistance, and ER stress. However, weight loss alone did show few or no action on some significant study findings, like liver steatosis, leptin, insulin, resistin, and amylin. Furthermore, hepatic inflammation mediated by MCP-1 and partially by TNF-alpha and IL6 were also not reduced by weight loss. Furthermore, weight loss alone did not lessen hepatic lipogenesis as determined by the findings of SREBP-1c, CHREBP, PPAR-alpha, and SIRT1. Semaglutide was implicated in improving glucose uptake and lessening ER stress by reducing GADD45, independent of weight loss.

Mice as an animal model for the study of adipose tissue and obesity / Ratones como modelo animal para el estudio del tejido adiposo y la obesidad

SUMMARY: The study of adipose tissue has gained increasing importance in the biomedical area due to its implications for health and obesity. Obesity is a situation of great concern mainly in the Western world due to its high prevalence and morbidity. Experimental studies on obesity often need a model where it is possible to carry out experiments, drug testing, and other therapeutic procedures, which are typically not possible in humans. Although several animals are used for obesity studies, rodents are by far the most used animals, and among rodents, mice are particularly indicated for this investigation. This mini review will introduce the challenging classification of obesity in rodents, paralleling human obesity, defining and classifying what an obese mouse is. The text will differentiate between white adipose tissue (WAT, aimed at endocrine secretion and lipogenesis) and brown adipose tissue (BAT, aimed at thermogenesis) and describe the browning process of white adipocytes in an adaptation to increase thermogenesis. The text will also describe the various types of body fat in mice with their differences and indications for investigation and teach how to recognize and dissect these fats. At the end of this introductory reading, the young researcher is expected to have acquired sufficient knowledge to start an experimental investigative project on obesity.

RESUMEN: El estudio del tejido adiposo ha ganado una importancia creciente en el área biomédica por sus implicaciones para la salud y la obesidad. La obesidad es una situación de gran preocupación, principalmente, en el mundo occidental debido a su alta prevalencia y morbilidad. Los estudios experimentales sobre la obesidad a menudo necesitan un modelo en el que sea posible realizar experimentos, pruebas de drogas y otros procedimientos terapéuticos, que normalmente no son posibles en humanos. Aunque se utilizan varios animales para estudios de obesidad, los roedores son, con mucho, los animales más utilizados y, entre los roedores, los ratones están especialmente indicados para esta investigación. Esta mini revisión presenta la desafiante clasificación de la obesidad en roedores, en paralelo con la obesidad humana, definiendo y clasificando qué es un ratón obeso. El texto diferencia entre tejido adiposo blanco (WAT, destinado a la secreción endocrina y lipogénesis) y tejido adiposo marrón (BAT, destinado a la termogénesis) y describe el proceso de pardeamiento de los adipocitos blancos en una adaptación para aumentar la termogénesis. El texto también describe los diversos tipos de grasa corporal en ratones con sus diferencias e indicaciones para la investigación y enseña cómo reconocer y diseccionar estas grasas. Al final de esta lectura introductoria, se espera que el joven investigador haya adquirido los conocimientos suficientes para iniciar un proyecto de investigación experimental sobre la obesidad.

Liver structural injury in leptin-deficient (ob/ob) mice: lipogenesis, fibrogenesis, inflammation, and apoptosis / Lesión estructural del hígado en ratones con deficiencia de leptina (ob/ob): lipogénesis, fibrogénesis, inflamación y apoptosis

SUMMARY: Nonalcoholic fatty liver disease (NAFLD) might progress the steatosis to nonalcoholic steatohepatitis (NASH), reaching a cirrhosis state and possibly hepatocellular carcinoma. The liver of three-month-old C57BL/6J mice (wild-type, WT group, n=10) and leptin- deficient obese mice (ob/ob group, n=10) were studied, focusing on the mechanisms associated with the activation of the hepatic stellate cells (HSCs) and pro-fibrogenesis. The obese ob/ob animals' liver showed steatosis, increased lipogenesis gene expressions, inflammation, increased pro-inflammatory gene expressions, inflammatory infiltrate, and potential apoptosis linked to a high Caspase 3 expression. In ob/ob mice, liver sections were labeled in the fibrotic zones by anti-alpha-smooth muscle actin (alpha-SMA) and anti-Reelin, but not in the WT mice. Moreover, the alpha-SMA gene expression was higher in the ob/ob group's liver than the WT group. The pro-fibrogenic gene expressions were parallel to anti- alpha-SMA and anti-Reelin immunofluorescence, suggesting HSCs activation. In the ob/ob animals, there were increased gene expressions involved with lipogenesis (Peroxisome proliferator-activated receptor-gamma, Cell death-inducing DFFA-like effector-c, Sterol regulatory element-binding protein-1c, and Fatty acid synthase), pro-fibrogenesis (Transforming growth factor beta1, Smad proteins- 3, Yes-associated protein-1, Protein platelet-derived growth factor receptor beta), pro-inflammation (Tumor necrosis factor-alpha, and Interleukin-6), and apoptosis (Caspase 3). In conclusion, the results in obese ob/ob animals provide a clue to the events in humans. In a translational view, controlling these targets can help mitigate the hepatic effects of human obesity and NAFLD progression to NASH.

RESUMEN: La enfermedad del hígado graso no alcohólico (HGNA) puede progresar de la esteatosis a esteatohepatitis no alcohólica (ENA), alcanzando un estado de cirrosis y posiblemente carcinoma hepatocelular. Se estudió el hígado de ratones C57BL / 6J de tres meses de edad (tipo salvaje, grupo WT, n = 10) y ratones obesos con deficiencia de leptina (grupo ob/ob, n = 10), centrándose en los mecanismos asociados con la activación de las células estrelladas hepáticas (HSC) y profibrogénesis. El hígado de los animales obesos ob/ob mostró esteatosis, aumento de la expresión génica de la lipogénesis, inflamación, aumento de la expresión génica proinflamatoria, infiltrado inflamatorio y posible apoptosis ligada a una alta expresión de Caspasa 3. En ratones ob/ob, las sec- ciones de hígado se marcaron en las zonas fibróticas con anti-alfa- actina de músculo liso (alfa-SMA) y anti-Reelin, pero no en los ratones WT. Además, la expresión del gen alfa-SMA fue mayor en el hígado del grupo ob/ob que en el grupo WT. Las expresiones génicas profibrogénicas fueron paralelas a la inmunofluorescencia anti-alfa-SMA y anti-Reelin, lo que sugiere la activación de las HSC. En los animales ob/ob, hubo un aumento de las expresiones génicas involucradas con la lipogénesis (receptor activado por proliferador de peroxisoma gamma, efector c similar a DFFA inductor de muerte celular, proteína de unión al elemento regulador de esterol-1c y sintasa de ácidos grasos), pro-fibrogénesis (factor de crecimiento transformante beta 1, proteínas Smad-3, proteína-1 asociada a Yes, receptor beta del factor de crecimiento derivado de plaquetas de proteínas), proinflamación (factor de necrosis tumoral alfa e interleucina-6) y apoptosis (caspasa 3). ). En conclusión, los resultados en animales obesos ob/ob proporcionan una pista de los eventos en humanos. Desde un punto de vista traslacional, el control de estos objetivos puede ayudar a mitigar los efectos hepáticos de la obesidad humana y la progresión de HGNA a ENA.

Hepatic mitochondria in diet-induced obese mice (stereology and molecular analysis) / Mitocondrias hepáticas en ratones obesos inducidos por la dieta (estereología y análisis molecular)

SUMMARY: The world population is going through an obesity epidemic that has severe consequences for the health system. This study focused on studying hepatic mitochondria in obese animals induced by a high-fat (HF) diet and used the model-based stereology in electron micrographs for the quantitative study. Besides, the gene expressions of molecular markers of mitochondrial biogenesis carnitine palmitoyltransferase 1a (Cpt 1α), mitochondrial transcription factor a (Tfam), uncoupling protein 3 (Ucp 3), and nuclear respiratory factor 1 (Nrf 1) were analyzed. The HF diet caused a weight gain of +1820 % comparing the control group (C) with the HF group (from 0.32±0.31 g to 5.5±0.39 g, P<0.001). The HF group showed fat droplets in the hepatocyte cytoplasm (steatosis) and less dense and large mitochondria in transmission electron microscopy. The mitochondria size (cross-section) did not show a significant difference between the groups C and HF. However, the mitochondria numerical density per area was 30 % less, the mitochondrial surface density (outer membrane) was 20 % less, and the mitochondrial volume density was 22 % less in the HF group than the C group. The gene expressions of molecular markers of mitochondrial biogenesis Cpt 1α, Tfam, Ucp 3, and Nrf 1 decreased in the HF group compared to the C group. The quantitative results match perfectly with the molecular ones of mitochondrial biogenesis markers. In the future, it will be crucial to verify if and how these data recover with the reduction of obesity, which would be of significant interest given the current obesity epidemic that affects the world population.

RESUMEN: La población mundial atraviesa una epidemia de obesidad que tiene graves consecuencias para el sistema de salud. Este estudio se centró en el análisis de las mitocondrias hepáticas en animales obesos inducidos por una dieta alta en grasas (HF) y utilizó la estereología basada en modelos en micrografías electrónicas para el estudio cuantitativo. Además, se analizaron las expresiones génicas de los marcadores moleculares de la biogénesis mitocondrial carnitina palmitoiltransferasa 1a (Cpt 1α), factor de transcripción mitocondrial a (Tfam), proteína desacoplante 3 (Ucp 3) y factor respiratorio nuclear 1 (Nrf 1). La dieta HF provocó un aumento de peso de +1820 % comparando el grupo de control (C) con el grupo HF (de 0,32 ± 0,31 g a 5,5 ± 0,39 g, P <0,001). El grupo HF mostró gotas de grasa en el citoplasma de los hepatocitos (esteatosis) y mitocondrias menos densas y grandes en la microscopía electrónica de transmisión. El tamaño de las mitocondrias (sección transversal) no mostró una diferencia significativa entre los grupos C y HF. Sin embargo, la densidad numérica de mitocondrias por área fue 30% menor, la densidad de superficie mitocondrial (membrana externa) fue 20 % menor y la densidad de volumen mitocondrial fue 22 % menor en el grupo HF que en el grupo C. Las expresiones génicas de los marcadores moleculares de la biogénesis mitocondrial Cpt 1α, Tfam, Ucp 3 y Nrf 1 disminuyeron en el grupo HF en comparación con el grupo C. Los resultados cuantitativos coinciden perfectamente con los moleculares de los marcadores de biogénesis mitocondrial. En el futuro, será crucial verificar si estos datos se recuperan y cómo se recuperan con la reducción de la obesidad, lo que sería de gran interés dada la actual epidemia de obesidad que afecta a la población mundial.