Gonadal Adipose Tissue Research Articles

Supplementation with inulin reverses cognitive flexibility alterations and modulates the gut microbiota in high-fat-fed mice

IntroductionAlterations in cognitive performance are associated with inadequate nutritional states and diet composition. Prebiotics, such as inulin, are substances that can modulate the gut microbiome and, consequently, brain function by producing metabolites such as short-chain fatty acids (SCFAs). This study aimed to evaluate the effect of supplementation with inulin on cognitive flexibility, body composition, and gut microbiota in a murine model exposed to a high-fat (HF) diet.MethodsCD1 mice were divided into five groups: control fed a standard diet (C), high-fat diet (HF), inulin (I), high-fat diet with inulin (HFI), and manipulation control (M). Dietary supplementation was administered for 6 weeks. Cognitive flexibility was assessed using the Attentional Set-Shifting Test (AST). In addition, body composition was measured via electrical bioimpedance and adipose tissue compartments of each mouse were removed and weighed. Finally, gut microbiota metataxonomic was analyzed through metataxonomic bacterial 16S rRNA sequencing.ResultsWe observed that HF group required more AST trials than the C, HFI, and I groups in the compound discrimination (CD) and extra-dimensional (ED) stages. Notably, the HFI group required fewer trials than the HF group in the ED stage (p = 0.0187). No significant differences in overall body composition were observed between the groups. However, the percentage of gonadal and peritoneal adipose tissue was significantly higher in the HF and I groups compared to the C group. Statistically significant differences in alpha diversity for gut microbiota were observed using the Shannon, Simpson, and Chao1 indices. The I group showed a decrease in bacterial diversity compared to the HF group. While no differences were observed between groups in the phyla Bacillota and Bacteroidotes, Clostridium bacteria represented a lower proportion of sequences in the I group compared to the C group. Additionally, Lactobacillus represented a lower proportion of sequences in the HF group compared to the C and I groups.DiscussionThese findings suggest that supplementation with inulin could be a useful approach to mitigate the negative effects of an HF diet on cognitive flexibility and modulate gut microbiota composition.

Liver adrenoceptor alpha-1b plays a key role in energy and glucose homeostasis in female mice.

The liver plays a major role in glucose and lipid homeostasis and acts as a key organ in the pathophysiology of metabolic diseases. Intriguingly, increased sympathetic nervous system (SNS) activity to the liver has been associated with the development and progression of type 2 diabetes and obesity. However, the precise mechanisms by which the SNS regulates hepatic metabolism remain to be defined. While liver alpha1-adrenoceptors were suggested to play a role in glucose homeostasis, the specific subtypes involved are unknown mainly because of the limitations of pharmacological tools. Here we generated and validated a novel mouse model allowing tissue-specific deletion of alpha-1b adrenoceptor (Adra1b) in hepatocytes to investigate the role of liver ADRA1B in energy and glucose metabolism. We found that selective deletion of Adra1b in mouse liver has limited metabolic impact in lean mice. However, loss of Adra1bin hepatocytes exacerbated diet-induced obesity, insulin resistance and glucose intolerance in female, but not male mice. In obese females, this was accompanied by reduced hepatic gluconeogenic capacity and reprogramming of gonadal adipose tissue with hyperleptinemia. Our data highlight sex-dependent mechanisms by which the SNS regulates energy and glucose homeostasis through liver ADRA1B.

Whole tomato lipidic extract improved sperm quality in obese rats induced by a high-carbohydrate diet.

Obesity represents a risk in the development of metabolic and oxidative stress (OS), as well as in male infertility. There is still no pharmacological treatment for obesity-induced male infertility, but the use of natural antioxidants has been proposed as a treatment. The aim of this work is to evaluate the effect of a whole tomato lipid extract on rats that decreased their fertility and spermatogenesis after being induced obese with a high carbohydrate diet. One hundred fourteen male Wistar rats of 12weeks of age were used. Two groups were randomly formed non-obese control group (C, n=54) and obese group (Ob, n=54) that received 30% w/v sucrose solution for 3 months. Subsequently, the C and Ob group were divided into two groups: vehicle (C-Vh and Ob-Vh) that received corn oil as vehicle and tomato lipid extract (C-Ex and Ob-Ex) that received whole tomato lipid extract. The groups that received a hypercaloric diet had a gain in visceral and retroperitoneal adipose tissue, an increase in total cholesterol and triglyceride levels, increased OS in the testis, and lesions in testicular histology, as well as a reduction in testicular size and sperm quality parameters (motility, viability, and concentration). Treatment with whole tomato lipid extract significantly decreased the weight of gonadal adipose tissue and OS, maintained testicular size, showed a significant increase in sperm quality parameters and improved histology of seminiferous tubules. These results demonstrate a greater therapeutic and beneficial effect of the tomato lipid extract on sperm quality parameters in obese rats and therefore on fertility.

Chronic Inorganic Nitrate Administration Increases the Expression of Genes Involved in the Browning of Gonadal Adipose Tissue in Ovariectomized Rats

Background and Objective:: Nitrate, as nitric oxide (NO) donor, has been suggested as a nutrition-based treatment for decreasing the risk of menopause-related obesity. This study aimed to specify the effects of chronic inorganic nitrate administration on uncoupling protein-1 (UCP-1), peroxisome proliferator-activated-receptor-γ (PPAR-γ) coactivator-1α (PGC-1α), and PPAR-γ expression in gonadal adipose tissue (GAT) of ovariectomized (OVX) rats. Methods:: Female rats were assigned to 3 groups: Control, OVX, and OVX+nitrate (n=7/group), which consumed water containing inorganic nitrate (100 mg/L) for 9 months. At month 9, GAT was used for the measurement of NO metabolites (NOx), mRNA levels of NO synthases (endothelial (eNOS), inducible (iNOS), neuronal (nNOS)), and mRNA and protein levels of UCP-1, PGC-1α, and PPAR-γ. Result:: OVX rats had lower NOx concentration (45%) and eNOS (38%) and nNOS (30%) expression in GAT that was restored to normal values following nitrate administration. OVX rats had significantly lower mRNA and protein levels of UCP-1 (83% and 30%), PGC-1α (65% and 39%), and PPAR-γ (66% and 34.5%) in GAT. Chronic inorganic nitrate administration in OVXrats increased mRNA and protein levels of UCP-1 (128% and 34%), PGC-1α (115% and 43%), and PPAR-γ (236% and 38%), respectively. Conclusion:: In OVX rats, chronic nitrate administration increased gene and protein levels of UCP-1, PGC-1α, and PPAR-γ in GAT, indicating the anti-obesity effects of nitrate are partially mediated by the white adipose tissue (WAT) browning. Moreover, the stimulatory effect of inorganic nitrate on the WAT browning in OVX rats was associated with blunting the OVXinduced NO deficiency in GAT.

Proteomic profiling points to the significance of adipocyte-derived extracellular vesicles in diet-induced obesity

Extracellular vesicles (EVs) are lipid-bilayer membrane-enclosed vesicles well known to mediate cell-cell communication to maintain normal physiological functions. The diverse cargo of EVs encompassing proteins, lipids and miRNAs represent potential biomarkers and therapeutic targets. However, the role of adipocyte-derived EVs (AdEVs) in obesity is still unknown. To address this, we performed proteomic profiling of AdEVs isolated from the C57BL/6 male mice that were fed either a normal chow diet (NCD) or a high-fat high-sucrose diet (HFHSD) for 12 weeks starting at 4 weeks of age. AdEVs were obtained, through ultracentrifugation, from the conditioned media of cultured adipocytes derived from gonadal adipose tissue. Nanoparticle tracking analysis (NTA) of AdEVs showed that adipocytes from mice fed HFHSD tended to release more AdEVs despite the comparable size of AdEVs relative to those of mice fed NCD. Subsequently, proteins were isolated, digested and labeled with TMTpro16-plex for proteomic analysis. Raw data were processed in Scaffold, and a general bioinformatic and functional analysis conducted in Ingenuity Pathway Analysis Qiagen (IPA) ( https://digitalinsights.qiagen.com/explore/ga-ipa?utm_source=QDI_GA_SA_IPA_1122_PF&cmpid=QDI_GA_IPA ) and Srplot identified over 1100 proteins in AdEVs (protein threshold: 99%, minim peptide:2, peptide threshold: 95%, 0.00% FDR). Of these, 58 proteins were identified as upregulated while 41 proteins were downregulated in HFHSD-fed mice (Fold Change > 2, adjusted p < 0.05). With IPA analysis, the top 3 influenced pathways including mitochondrial dysfunction (27%), Sirtuin signaling pathway (22%), and Granzyme A signaling (38%) are predicted to be activated while the oxidative phosphorylation (47%), estrogen receptor signaling (15%) and neutrophil extracellular trap signaling pathway (14%) are predicted to be inhibited. The Gene Oncology (GO) functional enrichment analysis in Srplot revealed the involvement of identified differentially expressed proteins in various biological processes such as lipid metabolism, catabolic process processes, and cellular respiration. Experiments are underway to validate specific proteins involved in these biological processes. Furthermore, analysis of cellular components highlighted three notable terms including myelin sheath, collagen-containing extracellular matrix and organelle inner membrane. In conclusion, the present study elucidates the significance of AdEVs in the context of diet-induced obesity and underscores the potential role of mitochondrial dysfunction in the initiation and progression of obesity and its associated diseases. NIH Veterans Affairs. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

A novel preclinical model of human lung cancer cachexia

Most patients with lung cancer are afflicted with cancer cachexia (CC), a syndrome characterized by wasting of muscle and fat tissues, which leads to poor treatment response and increased mortality. Pre-clinical models used to study CC often do not mimic the human condition, which may explain why there are no approved treatments for CC. To overcome this barrier, we sought to develop a model of lung CC that better recapitulates the pathoetiological characteristics of human lung CC using mice with a tamoxifen-inducible, lung epithelial cell (club cell)-specific KrasG12D allele ( G12D mice). We hypothesized that this model would mimic human CC in tumor location and burden, rate of progression, and tumor-driven tissue wasting. Following induction by tamoxifen injection, adenocarcinomas developed in the terminal bronchioles as early as 3.5 weeks post-induction and were accompanied by loss of 15% of animal body weight over a 12-week period. This weight loss began at 6 weeks and yielded a slow rate of CC progression (-1.9%/week) relative to currently available lung CC models (-5-10%/week). Body weight loss resulted from reductions in hindlimb muscle mass (18-30%) and profound depletion of inguinal and gonadal adipose tissue depots (60-70%) compared to age-matched wild-type (WT) littermates. At 6 weeks post-induction, fat tissue was reduced at the tissue and cellular levels while reductions in hindlimb muscle weight and fiber size were not observed. This fat loss corresponded with increased serum glycerol levels at 6 and 12 weeks, a metabolic characteristic that was also found in patients with lung cancer receiving treatment. Lung organoids were developed from G12D and WT mice. G12D organoids exhibited similarities in gene expression to human lung tumors ( RNAseq) and their conditioned medium (CM) elicited glycerol release from cultured 3T3L1 adipocytes compared to CM from WT organoids, suggesting that tumor-derived factors may contribute to early adipose tissue atrophy. Collectively, these findings suggest that G12D mice may be a valuable model, well-suited to identify mechanisms leading to CC and test preventative therapies. NIH R01 AR065826(MJT), NCI R21 CA283492(MJT), T32- HL076122-18(DBS/MEP), R01 CA273238 (YJ-H) and the University of Vermont Cancer Center. Funding support for RNAseq provided by Zymo Impact Initiative Grant (DBS). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The role of adipose tissue and subsequent liver tissue hypoxia in obesity and early stage metabolic dysfunction associated steatotic liver disease.

Obesity is linked to several health complication, including Metabolic Dysfunction Associated Steatotic Liver Disease (MASLD). Adipose tissue hypoxia has been suggested as an important player in the pathophysiological mechanism leading to chronic inflammation in obesity, and in the progression of MASLD. The study aims to investigate the effect of progressive obesity on adipose and liver tissue hypoxia. Male 8-week-old C57BL/6J mice were fed a high-fat high-fructose diet (HFHFD) or control diet (CD) for 4, 8, 12, 16 and 20 weeks. Serum ALT, AST and lipid levels were determined, and glucose and insulin tolerance testing was performed. Liver, gonadal and subcutaneous adipose tissue was assessed histologically. In vivo tissue pO2 measurements were performed in gonadal adipose tissue and liver under anesthesia. A PCR array for hypoxia responsive genes was performed in liver and adipose tissue. The main findings in the liver were validated in another diet-induced MASLD mice model, the choline-deficient L-amino acid defined high-fat diet (CDAHFD). HFHFD feeding induced a progressive obesity, dyslipidaemia, insulin resistance and MASLD. In vivo pO2 was decreased in gonadal adipose tissue after 8 weeks of HFHFD compared to CD, and decreased further until 20 weeks. Liver pO2 was only significantly decreased after 16 and 20 weeks of HFHFD. Gene expression and histology confirmed the presence of hypoxia in liver and adipose tissue. Hypoxia could not be confirmed in mice fed a CDAHFD. Diet-induced obesity in mice is associated with hypoxia in liver and adipose tissue. Adipose tissue hypoxia develops early in obesity, while liver hypoxia occurs later in the obesity development but still within the early stages of MASLD. Liver hypoxia could not be directly confirmed in a non-obese liver-only MASLD mice model, indicating that obesity-related processes such as adipose tissue hypoxia are important in the pathophysiology of obesity and MASLD.

Adipocyte lipolysis protects mice against Trypanosoma brucei infection

Trypanosoma brucei causes African trypanosomiasis, colonizing adipose tissue and inducing weight loss. Here we investigated the molecular mechanisms responsible for adipose mass loss and its impact on disease pathology. We found that lipolysis is activated early in infection. Mice lacking B and T lymphocytes fail to upregulate adipocyte lipolysis, resulting in higher fat mass retention. Genetic ablation of the rate-limiting adipose triglyceride lipase specifically from adipocytes (AdipoqCre/+-Atglfl/fl) prevented the stimulation of adipocyte lipolysis during infection, reducing fat mass loss. Surprisingly, these mice succumbed earlier and presented a higher parasite burden in the gonadal adipose tissue, indicating that host lipolysis limits parasite growth. Consistently, free fatty acids comparable with those of adipose interstitial fluid induced loss of parasite viability. Adipocyte lipolysis emerges as a mechanism controlling local parasite burden and affecting the loss of fat mass in African trypanosomiasis.

Differential depot-specific parameters of adipose tissue cellularity and thermogenesis in preobese congenic LA/Ntul//-cp rats

To determine the effects of adipose tissue development during early normal postweaning growth, groups of lean and obese LA/N//tul-cp rats were subjected to measures of caloric intake, linear growth and of adipose tissue mass, cell lipid content, and adipocyte number in principle adipose tissue depots at 6 weeks of age, prior to the expression of significant adiposity. Live body weights and daily caloric intake of obese > lean by 6 weeks of age, but parameters of linear growth were similar in both phenotypes. Resting metabolic rate (RMR) and the thermic response to norepinephrine (NE, 200 µg/KG BW, s.c.) of lean >> obese rats. Adipose tissue mass and combined fat pad mass:body weight ratio of Dorsal Subcutaneous (DOR), Retroperitoneal (RP), Gonadal (GON), and Interscapular brown adipose tissue (IBAT) depots were greater in the obese than lean phenotype, with the greatest magnitude of increase in the DOR subcutaneous depot. Adipocyte number was modestly greater in DOR subcutaneous depot, while adipocyte lipid content was greater in the RP and GON depots of obese but not lean rats. The IBAT mass and proportion of IBAT:body weight of obese >> lean. These results are consistent with the differential onset of adipose tissue depot growth initially occurs via hyperplasia in the dorsal subcutaneous depot and via hypertrophy in the RP and GON abdominal depots, while lean tissue development was of similar magnitude in both phenotypes at this age.

#5978 SUBCAPSULAR INJECTION OF EXTRACELLULAR VESICLES FROM MESENCHYMAL STEM CELLS, PROMOTED ADDITIONAL RENOPROTECTION IN AN EXPERIMENTAL MODEL OF CKD

Abstract Background and Aims Chronic kidney disease (CKD) is considered a public health concern worldwide, both due to its insidious and highly debilitating feature and to its high global prevalence. Clinical management of CKD is often achieved by the blockade of the renin-angiotensin-aldosterone system (RAAS). However, this treatment alone is not efficient to prevent CKD progression completely, motivating the scientific community to search for alternative treatments to control CKD progression and to detain its evolution to the end-stage renal failure. In this context, we have recently shown that the association of a single renal subcapsular injection of 2 × 106 adipose-derived mesenchymal stem cells (ASC) to RAAS blockade with the AT1RB Losartan (LOS) promoted greater renoprotection when compared to LOS monotherapy, leading to the normalization of urinary protein excretion (UPE) and to the regression of established glomerulosclerosis (GS), in experimental CKD. Since there are methodological limits for the number of ASC that can be injected under the renal capsule, and based on the current literature, which suggests the main beneficial effects of ASC are not due to direct in situ cell differentiation, but to paracrine factors produced and released by the ASC; in the present study we aimed to investigate if the association of a renal subcapsular injection of extracellular vesicles (EV) derived from ASC, to the oral treatment with LOS would promote additional renoprotective effects in a model of experimental CKD. Method The present experimental protocol was approved by the Ethics Committee for the Use of Experimental Animals of the University of São Paulo Medical School (CEUA-FMUSP No 1761/2022). EV were obtained from ASC isolated from gonadal adipose tissue of 5 male Wistar rats. Cells were cultured until P4, characterized by flow cytometry and in vitro differentiation, and kept under serum deprivation for 24 h. The conditioned culture media, containing the EV released by these cells, was ultracentrifuged and the resulting EV pellets were diluted in 100 μL of sterile PBS and used for the renal subcapsular injections. Experimental CKD was induced in 25 male Wistar rats through the surgical ligation of 2 from the 3 branches of the left renal artery, followed by the total nephrectomy of the right kidney, resulting in a 5/6 renal ablation. Additional 10 Sham-operated rats were used as control. After 15 days from surgery, the animals submitted to renal ablation were stratified into 3 groups, with closely similar mean values of body weight (BW), systolic blood pressure (SBP), UPE and urinary albumin excretion (UAE), before the start of the different treatments. Animals from CKD group were kept untreated, LOS and LOS+EV animals received diary 50 mg/Kg/d of Losartan, diluted in drinking water and LOS+EV rats underwent a second surgery for the renal subcapsular application of EV. All animals were followed until 30 days after CKD induction, when BW, SBP, UPE and UAE were analyzed again. Animals where then euthanized for the assessment of serum creatinine (SCr) and blood urea nitrogen (BUN) concentration, as well as for histological studies to determine the percentage of GS and the renal interstitial infiltration by macrophages (CD68). Results The association of a single subcapsular injection of EV derived from ASC, to the oral treatment with the AT1RB LOS, significantly improved the effects of this antihypertensive drug. CKD+LOS+EV animals exhibited normal SBP, in spite of having only 1/6 of functioning renal mass. Moreover, the combined treatment significantly reduced UAE and numerically diminished de percentage of glomerulosclerosis, compared to LOS alone. Detailed obtained results are presented in Table 1. Data are presented as Mean ± SE. Differences among groups were analyzed by one-way ANOVA: p<0.05 vs.*CONT, #CKD, †LOS. as Mean ± SE. Conclusion Despite the small number of animals in the association group, our preliminary results suggest EV from ASC to exert additional renoprotective effects when associated to LOS, especially regarding the control of SBP and the protection of the glomerular filtration barrier integrity.

Osteopontin Expression is Upregulated in Gonadal Adipose Tissue During Early Menopause Stage in Female Mice

Background: Menopausal women are at high risk of developing atherosclerosis. Reduced ovarian hormone production is a key feature of menopause, and it often leads to increased visceral adiposity and atherosclerosis. Osteopontin (OPN) is an inflammatory cytokine found in high levels in menopausal women, and in human atherosclerotic plaque. While recent studies report that macrophages in male epididymal white adipose tissue are able to produce OPN, less is known about the gonadal white adipose tissue (gWAT) in females. We hypothesize that OPN protein expression is up-regulated in gWAT in early stages of menopause, conferring gWAT as a source of OPN.Methods: To address our hypothesis, a bilateral ovariectomy in a surgical menopausal murine model was utilized. Twelve-week-old female C57BL/6 sexually mature mice were randomized into two experimental groups: Sham group (n=5) whose ovaries remained intact, and OVX group (n=6), who underwent ovariectomies, and were observed for four weeks therafter. At terminal experiments, gonadal white adipose tissue (gWAT) was collected for biochemical analysis. Results: As expected, OVX mice exhibited increased body weights (24.07 ± 0.85 g vs 21.06 ± 0.38 g controls, p<0.05) and increased gWAT mass (13.69 ± 1.421 mg/g vs 9.58 ± 0.55 mg/g control, p<0.05), indicating that early decline in female hormones is able to promote adiposity. Strikingly, greater OPN expression (2.57 ± 0.50 a.u vs. 0.76 ± 0.13 a.u sham group, n=3, p<0.05) was observed in the gWAT from the OVX group. Conclusion: Our results indicate that OPN expression in gWAT is increased during early stages of menopausal status, and suggest that gWAT could be a potential source of high levels of OPN in menopause. Our data suggest that female gWAT is not only an expanded fat depot but a metabolically active tissue contributing to an inflammatory state in menopause by an increased production of circulating cytokines such as OPN, which can ultimately contribute to inflammatory processes, including atherosclerosis. Funding: Diabetes Action to Maria Alicia Carrillo Sepulveda This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Strain and Depot-specific Differences in Adipose Tissues of Obese BFMI Mice.

Obesity is associated with the structural and functional disorders related to the molecules of the tissues, cells, and membranes. This study aimed to examine the alterations in the secretion of inflammatory cytokines and metabolic factors and structural changes in inguinal (IF) and gonadal (GF) adipose tissues at the molecular level. The IF and GF tissues of Berlin Fat Mouse Inbred (BFMI) lines namely BFMI852, BFMI856, BFMI860, BFMI861 obese and DBAJ control mouse lines were used for mRNA expression and Attenuated Total Reflection - Fourier Transform Infrared Spectroscopy (ATR-FTIR) studies. The mRNA levels of inflammatory cytokines including leptin, interleukin 6 (IL-6), tumor necrosis factor-alpha (Tnf-α), and insulin-like growth factor-1 (Igf-1), and peroxisome proliferator-activated receptor gamma 2 (Pparγ-2), were investigated using quantitative reverse transcriptase real-time PCR (qRT-PCR). Infrared spectroscopy does not provide information about specific proteins, instead, it gives information about overall (total) proteins, which is called global information. Therefore, in the current study, adequate information about secondary structures of adipose tissues proteins was obtained using artificial neural network (ANN) and secondary derivative-vector normalization methods based on the spectral profiles. According to the mRNA expression studies, high leptin resistance was found in all BFMI lines. Differences were observed in the levels of measured factors except for Igf-1 among BFMI lines. Protein secondary structure studies showed an increase in random coil contents, especially for BFMI860, which indicates denaturation of the proteins. Among the spontaneous obese BFMI mouse lines, the BFMI860 line is the most suitable for obesity studies. Obesity-induced effect on the adipose tissues varies considerably with location, type of adipose tissue, and animal line.

Intrauterine androgen exposure impairs gonadal adipose tissue functions of adult female rats

Prenatal androgen exposure induces fetal programming leading to alterations in offspring health and phenotypes that resemble those seen in women with Polycystic Ovary Syndrome. It has been described that prenatal androgenization affects the reproductive axis and leads to metabolic and endocrine disorders. Adipose tissue plays a crucial role in all these functions and is susceptible to programming effects. Particularly, gonadal adipose tissue is involved in reproductive functions, so dysfunctions in this tissue could be related to fertility alterations. We aimed to investigate the extent to which prenatal hyperandrogenization is able to alter the functionality of gonadal adipose tissue in female adult rats, including lipid metabolism, adipokines expression, and de novo synthesis of steroids. Pregnant rats were treated with 1 mg of testosterone from day 16 to day 19 of pregnancy, and female offspring were followed until 90 days of age, when they were euthanized. The prenatally hyperandrogenized (PH) female offspring displayed two phenotypes: irregular ovulatory (PHiov) and anovulatory (PHanov). Regarding lipid metabolism, both PH groups displayed disruptions in the main lipid pathways with altered levels of triglyceride and increased lipid peroxidation levels. In addition, we found that Peroxisome Proliferator-Activated Receptors (PPARs) alpha protein expression was decreased in both PH phenotypes (p < 0.05), but no changes were found in PPARγ protein levels. Furthermore, regarding adipokines, no changes were found in Leptin and Adiponectin protein levels, but Chemerin protein levels were decreased in the PHiov group (p < 0.05). Regarding de novo synthesis of steroids, the PHanov group showed increased protein levels of Cyp17a1 and Cyp19, while the PHiov group only showed decreased protein levels of Cyp19 (p < 0.05). These results suggest that prenatal androgen exposure affects females’ gonadal adipose tissue in adulthood, disturbing different lipid pathways, Chemerin expression, and de novo synthesis of steroids.

Improved β-cell function leads to improved glucose tolerance in a transgenic mouse expressing lipoprotein lipase in adipocytes

Lipoprotein lipase (LPL) hydrolyzes the triglyceride core of lipoproteins and also functions as a bridge, allowing for lipoprotein and cholesterol uptake. Transgenic mice expressing LPL in adipose tissue under the control of the adiponectin promoter (AdipoQ-LPL) have improved glucose metabolism when challenged with a high fat diet. Here, we studied the transcriptional response of the adipose tissue of these mice to acute high fat diet exposure. Gene set enrichment analysis (GSEA) provided mechanistic insight into the improved metabolic phenotype of AdipoQ-LPL mice. First, the cholesterol homeostasis pathway, which is controlled by the SREBP2 transcription factor, is repressed in gonadal adipose tissue AdipoQ-LPL mice. Furthermore, we identified SND1 as a link between SREBP2 and CCL19, an inflammatory chemokine that is reduced in AdipoQ-LPL mice. Second, GSEA identified a signature for pancreatic β-cells in adipose tissue of AdipoQ-LPL mice, an unexpected finding. We explored whether β-cell function is improved in AdipoQ-LPL mice and found that the first phase of insulin secretion is increased in mice challenged with high fat diet. In summary, we identify two different mechanisms for the improved metabolic phenotype of AdipoQ-LPL mice. One involves improved adipose tissue function and the other involves adipose tissue—pancreatic β-cell crosstalk.

11β-HSD1 contributes to age-related metabolic decline in male mice.

The aged phenotype shares several metabolic similarities with that of circulatory glucocorticoid excess (Cushing’s syndrome), including type 2 diabetes, obesity, hypertension, and myopathy. We hypothesise that local tissue generation of glucocorticoids by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), which converts 11-dehydrocorticosterone to active corticosterone in rodents (corticosterone to cortisol in man), plays a role in driving age-related chronic disease. In this study, we have examined the impact of ageing on glucocorticoid metabolism, insulin tolerance, adiposity, muscle strength, and blood pressure in both wildtype (WT) and transgenic male mice with a global deletion of 11β-HSD1 (11β-HSD1−/−) following 4 months high-fat feeding. We found that high fat-fed 11β-HSD1−/− mice were protected from age-related glucose intolerance and hyperinsulinemia when compared to age/diet-matched WTs. By contrast, aged 11β-HSD1−/− mice were not protected from the onset of sarcopenia observed in the aged WTs. Young 11β-HSD1−/− mice were partially protected from diet-induced obesity; however, this partial protection was lost with age. Despite greater overall obesity, the aged 11β-HSD1−/− animals stored fat in more metabolically safer adipose depots as compared to the aged WTs. Serum analysis revealed both WT and 11β-HSD1−/− mice had an age-related increase in morning corticosterone. Surprisingly, 11β-HSD1 oxo-reductase activity in the liver and skeletal muscle was unchanged with age in WT mice and decreased in gonadal adipose tissue. These data suggest that deletion of 11β-HSD1 in high fat-fed, but not chow-fed, male mice protects from age-related insulin resistance and supports a metabolically favourable fat distribution.

Chronic nitrate administration increases the expression the genes involved in the browning of white adipose tissue in female rats.

Nitrate, a nitric oxide (NO) donor, has antiobesity effect in female rats. This study hypothesized that the antiobesity effect of nitrate in female rats is due to the browning of white adipose tissue (WAT). Female Wistar rats (aged 8 months) were divided into two groups (n = 10/group): the control group received tap waterand the nitrate group received water containing 100 mg/L of sodium nitrate for 9 months. At months 0, 3, 6, and 9, obesity indices were measured. At month 9, gonadal adipose tissue was used to measure messenger RNA (mRNA) and protein levels of peroxisome proliferator-activated receptor-γ (PPAR-γ), PPAR-γ coactivator 1-α (PGC1-α), uncoupling protein 1 (UCP1), and adipocyte density and area. After the 9-month intervention, nitrate-treated rats had lower body weight, body mass index, thoracic circumference, and abdominal circumference by 6.4% (p = .012), 9.1% (p = .029), 6.0% (p = .056), and 5.7% (p = .098), respectively. In addition, nitrate-treated rats had higher PPAR-γ (mRNA: 1.78-fold, p = .016 and protein: 19%, p = .076), PGC1-α (mRNA: 1.69-fold, p = .012 and protein: 68%, p = .001), and UCP1 (mRNA: 2.50-fold, p = .001 and protein: 81%, p = .001) in gonadal adipose tissue. Nitrate also reduced adipocyte area by 35% (p = .054) and increased adipocyte density by 31% (p = .086). In conclusion, antiobesity effect of nitrate in female rats is associated with increased browning of gonadal adipose tissue as indicated by higher expression of PPAR-γ, PGC1-α, and UCP1 and reduced adipocyte area and increased adipocyte density.

Adipose cells and tissues soften with lipid accumulation while in diabetes adipose tissue stiffens

Adipose tissue expansion involves both differentiation of new precursors and size increase of mature adipocytes. While the two processes are well balanced in healthy tissues, obesity and diabetes type II are associated with abnormally enlarged adipocytes and excess lipid accumulation. Previous studies suggested a link between cell stiffness, volume and stem cell differentiation, although in the context of preadipocytes, there have been contradictory results regarding stiffness changes with differentiation. Thus, we set out to quantitatively monitor adipocyte shape and size changes with differentiation and lipid accumulation. We quantified by optical diffraction tomography that differentiating preadipocytes increased their volumes drastically. Atomic force microscopy (AFM)-indentation and -microrheology revealed that during the early phase of differentiation, human preadipocytes became more compliant and more fluid-like, concomitant with ROCK-mediated F-actin remodelling. Adipocytes that had accumulated large lipid droplets were more compliant, and further promoting lipid accumulation led to an even more compliant phenotype. In line with that, high fat diet-induced obesity was associated with more compliant adipose tissue compared to lean animals, both for drosophila fat bodies and murine gonadal adipose tissue. In contrast, adipose tissue of diabetic mice became significantly stiffer as shown not only by AFM but also magnetic resonance elastography. Altogether, we dissect relative contributions of the cytoskeleton and lipid droplets to cell and tissue mechanical changes across different functional states, such as differentiation, nutritional state and disease. Our work therefore sets the basis for future explorations on how tissue mechanical changes influence the behaviour of mechanosensitive tissue-resident cells in metabolic disorders.

Methionine Restriction Affects Metabolic Parameters in a Fibroblast Growth Factor 21- and Sex-Dependent Manner

ObjectivesIn rodents, dietary restriction of the amino acid methionine produces profound protection against obesity and obesity-related comorbidities. Fibroblast growth factor 21 (FGF21) is now recognized as an important mediator of methionine restriction's (MR) metabolic benefits. Most preclinical work investigating the impact of diet on weight gain and metabolism has been conducted in males, leaving a gap in our understanding of female responses to dietary changes. This study aimed to examine the impact of high-fat diet (HFD) feeding and MR on body weight and adiposity in male and female mice. Furthermore, we sought to determine the sex-dependent role of endogenous FGF21 in mediating metabolic responses to HFD and MR.MethodsMale and female wild-type (WT) and Fgf21 knockout (Fgf21−/−) mice were fed low-fat diet (LFD) or HFD versions of control (0.86% methionine) or MR (0.17% methionine) diets for 5 weeks. Average body weight (BW) and food intake were recorded weekly. Insulin tolerance tests were performed at week 4. After 5 weeks, mice were euthanized, and adipose depots were collected.ResultsNeither HFD nor MR significantly altered BW of female mice regardless of genotype. However, while HFD did not significantly affect BW, MR significantly reduced BW of both WT and Fgf21−/− males (p < 0.0001). Neither HFD nor MR significantly altered adiposity (gonadal adipose tissue weight/body weight) in female mice regardless of genotype. However, HFD significantly increased adiposity in male WT and Fgf21−/− mice, and MR prevented this increase in both genotypes. MR increased energy intake in LFD- and HFD-fed WT mice. The ability of MR to increase energy intake was abolished in LFD- and HFD-fed Fgf21−/− mice.ConclusionsThe effects of MR on BW and adiposity are sex-dependent, but FGF21-independent. Short-term HFD feeding affects adiposity differently in males and females. The effects of MR on energy intake are dependent upon FGF21. As the field progresses towards developing FGF21 as a therapeutic agent, it will be essential to understand its impact on both sexes.Funding SourcesSources Center for Neuroinflammation and Cardiometabolic Diseases Seed Grant.

T Cells Contribute to Lipid Deposition in Male and Female Dahl Rats Fed a High Saturated Fat Diet

BackgroundThe Dahl rat has been used as a model of high fat diet (HFD)‐induced hypertension and adiposity. Genetic deletion of T cells blunts HFD‐induced hypertension. However, it is not clear if deletion of T cells can also reduce the adiposity caused by the HFD. T cells have been shown to play a role in many inflammatory conditions which are characterized by dyslipidemia. Therefore, the goal of the current study was to test the hypothesis that deletion of T cells prevents lipid deposits in the liver and adipose tissue.Methods5‐week‐old male and female wildtype Dahl (WT; n=9‐19/group) or Dahl rats lacking T cells (CD247 knock out [KO] rats; n=3‐7/group) were randomized to either a control normal fat diet (NF; 7.2% calories from fat) or a high fat diet (HF; 36% calories from saturated fat) for 10 weeks. Following treatment, a subset of livers were processed for hematoxylin and eosin staining and liver steatosis was scored. Gonadal adipose tissue was extracted and weighed.ResultsTen weeks of HFD increased liver steatosis in WT males and females (PInteraction=0.84, PDiet=0.01, Psex=0.75, Table 1), but not in T cell deficient animals (PInteraction=0.35, PDiet=0.29, Psex=0.04). While HFD increased gonadal adipose tissue weight in both males and females, this weight was increased more in the females (PInteraction=0.006, PDiet&lt;0.0001, Psex&lt;0.0001). T cell deletion abolished the HFD‐induced weight gain in gonadal adipose tissue (PInteraction=0.98, PDiet=0.14, Psex=0.01).DiscussionThese data confirm the hypothesis that T cell KO prevents the HFD‐induced increases in adiposity in the liver and gonadal adipose tissue. Lipid deposits in these areas are detrimental for cardiovascular health. Lipid deposition in the liver is a strong predictor of insulin resistance. Furthermore, chronic ingestion of a HFD increases adipose tissue expansion, which promotes inflammation and oxidative stress. Since the majority of Americans are consuming large amounts of fat, investigating the mechanisms underlying HFD‐induced adiposity will help identify targets to improve cardiovascular health.

Visceral adipose tissue remodeling in pancreatic ductal adenocarcinoma cachexia: the role of activin A signaling

Pancreatic ductal adenocarcinoma (PDAC) patients display distinct phenotypes of cachexia development, with either adipose tissue loss preceding skeletal muscle wasting or loss of only adipose tissue. Activin A levels were measured in serum and analyzed in tumor specimens of both a cohort of Stage IV PDAC patients and the genetically engineered KPC mouse model. Our data revealed that serum activin A levels were significantly elevated in Stage IV PDAC patients in comparison to age-matched non-cancer patients. Little is known about the role of activin A in adipose tissue wasting in the setting of PDAC cancer cachexia. We established a correlation between elevated activin A and remodeling of visceral adipose tissue. Atrophy and fibrosis of visceral adipose tissue was examined in omental adipose tissue of Stage IV PDAC patients and gonadal adipose tissue of an orthotopic mouse model of PDAC. Remarkably, white visceral adipose tissue from both PDAC patients and mice exhibited decreased adipocyte diameter and increased fibrotic deposition. Strikingly, expression of thermogenic marker UCP1 in visceral adipose tissues of PDAC patients and mice remained unchanged. Thus, we propose that activin A signaling could be relevant to the acceleration of visceral adipose tissue wasting in PDAC-associated cachexia.