Adipocyte Size Research Articles

Infliximab modifies CD74-mediated lymphatic abnormalities and adipose tissue alterations in creeping fat of Crohn's disease.

Lymphatic abnormalities are essential for pathophysiologic changes of creeping fat (CrF) in Crohn's disease (CD). Anti-tumor necrosis factor (TNF) therapy has been proved to alleviate CrF lesions, however, whether it achieves these by remodeling lymphatics is unknown. CD74 expression was detected in CrF and uninvolved mesentery of CD patients. Lymphatic functions in vitro were evaluated and lymphatic endothelium barrier were checked by transendothelial electrical resistance (TEER) and FITC-Dextran permeability. Protein level of tight junction and signaling pathways were detected by western blotting. CD74 was upregulated in LECs of CrF and positively correlated with TNF-α synthesis. This was suppressed by IFX administration. In vitro, TNF-α stimulated LECs to express CD74 through NF-κB signaling pathway, and this was rescued by IFX. CD74 downregulation suppressed the abilities of LECs in proliferation, migration and tube formation. Interaction of CD74-MIF impaired LECs' barrier via reducing tight junction proteins in an ERK1/2-dependent manner, which was reversed by CD74 downregulation. Consistently, the CD patients receiving IFX therapy displayed decreased lymphangiogenesis and improved mesenteric lymphatic endothelium barrier, companied with reduced adipocyte size and adipokine levels in CrF. Anti-TNF therapy could modify pathological changes in CrF by alleviating CD74-mediated lymphatic abnormalities.

Adipose tissue analysis toolkit (ATAT) for automated analysis of adipocyte size and extracellular matrix in white adipose tissue

Adipose tissue analysis toolkit (ATAT) for automated analysis of adipocyte size and extracellular matrix in white adipose tissue

PM2.5-induced cellular senescence drives brown adipose tissue impairment in middle-aged mice

Airborne fine particulate matter (PM2.5) exposure is closely associated with metabolic disturbance, in which brown adipose tissue (BAT) is one of the main contributing organs. However, knowledge of the phenotype and mechanism of PM2.5 exposure-impaired BAT is quite limited. In the study, male C57BL/6 mice at three different life phases (young, adult, and middle-aged) were simultaneously exposed to concentrated ambient PM2.5 or filtered air for 8 weeks using a whole-body inhalational exposure system. H&E staining and high-resolution respirometry were used to assess the size of adipocytes and mitochondrial function. Transcriptomics was performed to determine the differentially expressed genes in BAT. Quantitative RT-PCR, immunohistochemistry staining, and immunoblots were performed to verify the transcriptomics and explore the mechanism for BAT mitochondrial dysfunction. Firstly, PM2.5 exposure caused altered BAT morphology and mitochondrial dysfunction in middle-aged but not young or adult mice. Furthermore, PM2.5 exposure increased cellular senescence in BAT of middle-aged mice, accompanied by cell cycle arrest, impaired DNA replication, and inhibited AKT signaling pathway. Moreover, PM2.5 exposure disrupted apoptosis and autophagy homeostasis in BAT of middle-aged mice. Therefore, BAT in middle-aged mice was more vulnerable to PM2.5 exposure, and the cellular senescence-initiated apoptosis, autophagy, and mitochondrial dysfunction may be the mechanism of PM2.5 exposure-induced BAT impairment.

Alpha-Lipoic Acid Induces Adipose Tissue Browning through AMP-Activated Protein Kinase Signaling in Vivo and in Vitro.

AMP-activated protein kinase (AMPK) is a key enzyme for cellular energy homeostasis and improves metabolic disorders. Brown and beige adipose tissues exert thermogenesis capacities to dissipate energy in the form of heat. Here, we investigated the beneficial effects of the antioxidant alpha-lipoic acid (ALA) in menopausal obesity and the underlying mechanisms. Female Wistar rats (8 weeks old) were subjected to bilateral ovariectomy (Ovx) and divided into four groups: Sham (n=8), Ovx (n=11), Ovx+ALA2 (n=10), and Ovx+ALA3 (n=6) (ALA 200 and 300 mg/kg/day, respectively; gavage) for 8 weeks. 3T3-L1 cells were used for in vitro study. Rats receiving ALA2 and ALA3 treatment showed significantly lower levels of body weight and white adipose tissue (WAT) mass than those of the Ovx group. ALA improved plasma lipid profiles including triglycerides, total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol. Hematoxylin & eosin staining of inguinal WAT showed that ALA treatment reduced Ovx-induced adipocyte size and enhanced uncoupling protein 1 (UCP1) expression. Moreover, plasma levels of irisin were markedly increased in ALA-treated Ovx rats. Protein expression of brown fat-specific markers including UCP1, PRDM16, and CIDEA was downregulated by Ovx but markedly increased by ALA. Phosphorylation of AMPK, its downstream acetyl-CoA carboxylase, and its upstream LKB1 were all significantly increased by ALA treatment. In 3T3-L1 cells, administration of ALA (100 and 250 μM) reduced lipid accumulation and enhanced oxygen consumption and UCP1 protein expression, while inhibition of AMPK by dorsomorphin (5 μM) significantly reversed these effects. ALA improves estrogen deficiency-induced obesity via browning of WAT through AMPK signaling.

Abstract PS07-08: Bazedoxifene plus conjugated estrogen reduces mammary proliferation markers and improves adipocyte size, gut microbiome, and metabolic health: Findings from a preclinical model of obesity and breast cancer risk

Abstract Background: Many women at high risk for breast cancer will not take tamoxifen or aromatase inhibitors for cancer prevention due to concern of side effects including hot flashes. Further, tamoxifen has detrimental metabolic effects in some overweight/obese women. Duavee®, a tissue-selective complex of bazedoxifene + conjugated estrogen, is FDA-approved for relief of hot-flashes and prevention of osteoporosis. Preclinical studies suggest favorable metabolic effects and potential for breast cancer risk reduction. In a single arm clinical trial, BZA+CE reduced Ki-67 and mammographic density (PMID: 31420361), and this combination is currently being assessed further in a Phase IIB trial of postmenopausal high risk women with vasomotor symptoms. Here, we examined the modifying effects of obesity on response to BZA+CE in a rodent model of obesity and breast cancer risk. Methods: Rats received carcinogen at 7-weeks of age to induce mammary tumors and were fed a high-fat diet (46% kcal fat) to promote obesity. Lean and obese rat were selected based on adiposity at 16 weeks. Separate cohorts of lean and obese ovary-intact or ovariectomized (OVX) rats were randomized to a daily dose of BZA+CE or placebo control for 8 weeks. We assessed tumor development throughout the study and end of study RNA from mammary glands was analysed by gene expression microarray (Affymetrix). We also analyzed body weight/composition, markers of metabolic health (circulating glucose, insulin, adiponectin), as well as changes in the gut microbiome (metagenomic sequencing on DNA isolated from baseline and end-of-study fecal samples) in response to BZA+CE. Results: BZA+CE improved metabolic health in both ovary intact and OVX rats, including reduced body weight and % body fat, particularly in the visceral regions. These effects were greater in obese rats compared to lean. BZA+CE reduced the number of large adipocytes and increased small (insulin sensitive) adipocytes in the mammary adipose, indicating benefical changes in local tumor microenvironment. We found no evidence that Duavee® promoted tumor development or growth in ovary-intact or OVX’d rats. Gene set enrichment analysis (GSEA) of microarray data showed enrichment of cell proliferation pathways in MG from obese rats and these same pathways were downregulated with BZA+CE, consistent with anti-cancer effects. Analysis of the microbiome found that BZA+CE increased proportional abudance of Odoribacter laneus in the gut, regardless of lean/obese or intact/OVX status. Previous studies have demonstrated that this bacterim improves glucose control and reduces inflammatory cytokines when administered to obese mice, suggesting a possible mechanistic link in this study. Conclusions: Unlike traditional SERMs that can have negative metabolic effects, BZA+CE improved whole body and mammary gland metabolic health and reduced expression of cell proliferation pathways, particularly in obese rats. Prelminary data suggest that changes in the gut microbiome could contribute, at least in part, to these effects. Together this supports BZA+CE (Duavee) as an agent with potential beneficial effects on breast cancer risk reduction and improvements in metabolic health in women with obesity. Further analyses will guide assessment of outcomes in an ongoing parallel clinical study in postmenopausal women at high risk for breast cancer. Citation Format: Katherine L. Cook, Ramsey Jenshcke, Karen Corleto, Carol Fabian, Stephen Hursting, Bruce Kimler, Danilo Landrock, Erin Giles. Bazedoxifene plus conjugated estrogen reduces mammary proliferation markers and improves adipocyte size, gut microbiome, and metabolic health: Findings from a preclinical model of obesity and breast cancer risk [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS07-08.

The Influence of Subcutaneous and Visceral Adipocyte Geometries on Metabolic Parameters and Metabolic Regulating Hormones in Obese and Non-Obese Subjects

Adipose tissue plays a pivotal role in endocrine and metabolic homeostasis. This study aimed to compare subcutaneous and visceral adipocyte measurements, including area, shortest diameter, longest diameter, and perimeter, between groups of different metabolic profiles; and to determine correlations of adipocyte geometries with metabolic parameters and hormones in obese (n=20) and non-obese subjects (n=14). We hypothesized that geometries of subcutaneous and visceral adipocytes differ between groups with distinct metabolic conditions, and that their measurements correlate with obesity parameters, metabolic profiles, and hormones differently within subcutaneous and visceral adipocyte parameters as well as between obese and non-obese subjects. A total of 34 subjects were classified based on insulin resistance, using the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) >2.3, and the presence of hypertension (HT), defined as systolic blood pressure (SBP)/diastolic blood pressure (DBP) ≥130/80 mmHg. These subjects underwent open abdominal surgery, with blood sample collection in a fasting state before the operation, and abdominal subcutaneous and omental (visceral) adipose tissue collection during the operation. Subjects with insulin resistance (n=6) and those with HT (n=15) both had a greater size of visceral adipocytes compared to those without insulin resistance (n=28) or HT (n=19), respectively; however, there were no significant differences in subcutaneous adipocyte size between the groups. For correlation analyses in obese subjects, subcutaneous adipocyte measurements exhibited significant positive correlations with visceral adipocyte measurements (R=0.592-0.630); while they showed significant negative correlations with cholesterol (R=-0.573) and serum visfatin (R=-0.610), all with p<0.05. Furthermore, in obese subjects, visceral adipocytes geometries were positively correlated with body weight, waist circumference, and hip circumference (R=0.575-R=0.607), all with p<0.05. In non-obese subjects, geometries of subcutaneous adipocytes were significantly positively correlated with body weight, BMI, waist circumference, and visceral adipocyte size (R=0.555-0.642); while were negatively correlated with serum adiponectin (R=(-0.608)-(-0.676)), all with p<0.05. Furthermore, in non-obese subjects, the measurements of visceral adipocytes were significantly positively correlated with body weight, BMI, serum leptin levels, serum leptin/adiponectin ratio, waist circumference, and DBP (R=0.555-0.836); while were negatively correlated with serum adiponectin (R=(-0.608)-(-0.647), all with p<0.05. These results suggest that hypertrophy of visceral adipocytes, rather than subcutaneous adipocytes, could contribute to insulin resistance and hypertension. Subcutaneous adipocyte size in obese subjects was not correlated with obesity parameters but was negatively correlated with cholesterol and visfatin levels potentially reflecting a protective effect or a compensatory mechanism in which an increase in subcutaneous fat might be a response to store excess lipids more safely when visceral fat capacity is limited. In non-obese subjects, visceral adipocyte geometries were positively correlated with DBP but inversely related to serum levels of adiponectin, an anti-inflammatory adipokine, indicating that larger adipocytes in non-obese individuals are not benign but indicative of early metabolic derangement. In conclusion, subcutaneous fat in obese individuals may represent a potentially protective effect or compensatory response to metabolic disturbance induced by excess visceral fat. In non-obese individuals, a larger visceral adipocyte size could signal early metabolic alterations, even in the absence of obesity. The research was funded by the Faculty of Medicine Siriraj Hospital Research Fund ((IO) R015332009). 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 Microvascular Rarefaction in Dysfunctional Pericardial Adipose Tissue

Pericardial adipose tissue (PAT) in obesity has been shown to be an independent risk factor for coronary heart disease but the underlying mechanism remains incompletely understood. We aimed to elucidate the interrelationship between PAT expansion and the adipose tissue vascularization. PAT samples were collected from patients with coronary heart disease (19 patients; age: 48-79; BMI: 22.29-41.09). Tissue samples were stained using H&E and the number and size of adipocytes was quantified using unbiased techniques via AdipoCount and ImageJ. PAT samples, cut 40 μm thick, were immunolabelled using DyLight 594 fluorescent tomato-lectin dye followed by quantification of the tissue vasculature using an unbiased, automatic 3D reconstruction (Vesselucida360). Angiogenesis was quantified using an ex vivo angiogenic assay whereby pericardial vessels were isolated, cut, and embedded in a collagen matrix sustained with growth factors; number of sprouts were used as a measure of angiogenic potential and were further analyzed for length and branching in ImageJ. Patients exhibited an increased adipocyte size as BMI increased with measures of vascularization, such as number of branching nodes and total vessel length, showed a negative correlation to increasing BMI. Vessel volume and vessel surface area showed no correlation to patient BMI. Angiogenic potential, measured by the number of vessel sprouts, sprouting length, branching length, and branching interval, showed a significant association with increasing BMI. Our data show that while adipocyte size increases with an increasing BMI, the PAT vascularization had a negative correlation to increasing BMI. These results suggest that the vasculature is insuffcient to supply the increasing PAT demand, leading to impaired perfusion and eventual adipose tissue dysfunction. However, there was a significant increase in angiogenic potential that shows that when provided with growth factors, these vessels have the ability to increase their angiogenic potential, yet in vivo the vascular angiogenic response may be hindered, which needs to be further studied. T32 HL155011 (KAF) F31 NS132564 (KAF). 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.

Ghrelin and leptin gene expression, and adipocytes size as biomarkers in obesity rats model with Citrus amblycarpa peels extract supplementation

Ghrelin and leptin gene expression, and adipocytes size as biomarkers in obesity rats model with Citrus amblycarpa peels extract supplementation

Nr4a3 Loss Impairs Adipose Mitochondrial Respiration Through Downregulaion of Mek1

Type 2 diabetes mellitus (T2D) is a chronic condition affecting nearly half a billion people worldwide. Symptoms of T2D include impaired glucose tolerance, decreased insulin secretion and significant weight gain. While the symptoms of T2D are well-documented, the underlying pathology remains unclear. Recent research has indicated the critical role of the nuclear receptor Nr4a3 in the development of glucose intolerance and weight gain. In individuals with T2D, the Nr4a3 promoter is hypermethylated, leading to decreased Nr4a3 expression. Elucidating the role of Nr4a3 in mitochondrial respiration in adipose will help define the mechanism of T2D onset and treatment. Here we demonstrate the effect of systemic Nr4a3 loss. Full body Nr4a3 KO animals were fed a standard diet. Male, but not female, Nr4a3 KO mice demonstrate impaired glucose and insulin tolerance. Male Nr4a3 KO mice have normal muscle, liver, and kidney respiration rates, while adipose tissue respiration is impaired. The impaired adipose respiration corresponds with increased mass of all adipose depots, increased adipocyte size, and increased lipid droplet size. The analysis of electron transport chain and tricarboxylic acid complex proteins did not reveal significant differences. Instead, the altered respiration is attributed to a decreased Mek1 protein level, and decreased phosphorylation and activation of its downstream target DRP1. Our data demonstrate the critical role of Nr4a3 in adipose tissue through regulating mitochondrial function. NIH R15DK124835-01A1. 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.

Senp7 deficiency impairs lipid droplets maturation in white adipose tissues via Plin4 deSUMOylation

Lipid metabolism is important for the maintenance of physiological homeostasis. Several members of the SUMO-specific protease (SENP) family have been reported as the regulators of lipid homeostasis. However, the function of Senp7 in lipid metabolism remains unclear. In this study, we generated both conventional and adipocyte-specific Senp7 knockout mice to characterize the role of Senp7 in lipid metabolism homeostasis. Both Senp7-deficient mice displayed reduced white adipose tissue mass and decreased size of adipocytes. By analyzing the lipid droplet morphology, we demonstrated that the lipid droplet size was significantly smaller in Senp7-deficient adipocytes. Mechanistically, Senp7 could deSUMOylate the perilipin family protein Plin4 to promote the lipid droplet localization of Plin4. Our results reveal an important role of Senp7 in the maturation of lipid droplets via Plin4 deSUMOylation.

Deletion of Impdh2 in adipocyte precursors limits the expansion of white adipose tissue and enhances metabolic health with overnutrition

The equilibrium between the hypertrophic growth of existing adipocytes and adipogenesis is vital in managing metabolic stability in white adipocytes when faced with overnutrition. Adipogenesis has been established as a key player in combating metabolic irregularities caused by various factors. However, the benefits of increasing adipogenesis-mediated white adipose tissue (WAT) expansion for metabolic health regulation remain uncertain. Our findings reveal an increase in Impdh2 expression during the adipogenesis phase, both in vivo and in vitro. Xmp enhances adipogenic potential by fostering mitotic clonal expansion (MCE). The conditional knockout of Impdh2 in adipocyte progenitor cells(APCs) in adult and aged mice effectively curbs white adipose tissue expansion, ameliorates glucose tolerance, and augments energy expenditure under high-fat diet (HFD). However, no significant difference is observed under normal chow diet (NCD). Concurrently, the knockout of Impdh2 in APCs significantly reduces the count of new adipocytes induced by HFD, without affecting adipocyte size. Mechanistically, Impdh2 regulates the proliferation of APCs during the MCE phase via Xmp. Exogenous Xmp can significantly offset the reduction in adipogenic abilities of APCs due to Impdh2 deficiency. In summary, we discovered that adipogenesis-mediated WAT expansion, induced by overnutrition, also contributes to metabolic abnormalities. Moreover, the pivotal role of Impdh2 in regulating adipogenesis in APCs offers a novel therapeutic approach to combat obesity.

Xiaozhi formula attenuates non-alcoholic fatty liver disease by regulating lipid metabolism via activation of AMPK and PPAR pathways

BackgroundXiaozhi formula (XZF) is a practical Chinese herbal formula for the treatment of non-alcoholic fatty liver disease (NAFLD), which possesses an authorized patent certificate issued by the State Intellectual Property Office of China (ZL202211392355.0). However, the underlying mechanism by which XZF treats NAFLD remains unclear. PurposeThis study aimed to explore the main component of XZF and its mechanism of action in NAFLD treatment. MethodsUHPLC-Q-Orbitrap HRMS was used to identify the components of the XZF. A high-fat diet (HFD)-induced NAFLD mouse model was used to demonstrate the effectiveness of XZF. Body weight, liver weight, and white fat weight were recorded to evaluate the therapeutic efficacy of XZF. H&E and Oil Red O staining were applied to observe the extent of hepatic steatosis. Liver damage, lipid metabolism, and glucose metabolism were detected by relevant assay kits. Moreover, the intraperitoneal insulin tolerance test and the intraperitoneal glucose tolerance test were employed to evaluate the efficacy of XZF in insulin homeostasis. Hepatocyte oxidative damage markers were detected to assess the efficacy of XZF in preventing oxidative stress. Label-free proteomics was used to investigate the underlying mechanism of XZF in NAFLD. RT-qPCR was used to calculate the expression levels of lipid metabolism genes. Western blot analysis was applied to detect the hepatic protein expression of AMPK, p-AMPK, PPARɑ, CPT1, and PPARγ. Results120 compounds were preliminarily identified from XZF by UHPLC-Q-Orbitrap HRMS. XZF could alleviate HFD-induced obesity, white adipocyte size, lipid accumulation, and hepatic steatosis in mice. Additionally, XZF could normalize glucose levels, improve glucolipid metabolism disorders, and prevent oxidative stress damage induced by HFD. Furthermore, the proteomic analysis showed that the major pathways in fatty acid metabolism and the PPAR signaling pathway were significantly impacted by XZF treatment. The expression levels of several lipolytic and β-oxidation genes were up-regulated, while the expression of fatty acid synthesis genes declined in the HFD + XZF group. Mechanically, XZF treatment enhanced the expression of p-AMPK, PPARɑ, and CPT-1 and suppressed the expression of PPARγ in the livers of NAFLD mice, indicating that XZF could activate the AMPK and PPAR pathways to attenuate NALFD progression. ConclusionXZF could attenuate NAFLD by moderating lipid metabolism by activating AMPK and PPAR signaling pathways.

Liraglutide promotes UCP1 expression and lipolysis of adipocytes by promoting the secretion of irisin from skeletal muscle cells

Although Liraglutide (Lira) increases serum irisin levels in type 2 diabetes mellitus (T2DM), it is unclear whether it induces expression of uncoupling protein 1 (UCP1) of adipocytes via promoting irisin secretion from skeletal muscle. Male T2DM rats were treated with 0.4 mg/kg/d Lira twice a day for 8 weeks, and the protein expression of phosphorylated AMP kinase (p-AMPK), phosphorylated acetyl-CoA carboxylase 1 (p-ACC1) and UCP1 in white adipose tissues were detected. Differentiated C2C12 cells were treated with palmitic acid (PA) and Lira to detect the secretion of irisin. Differentiated 3T3-L1 cells were treated with irisin, supernatant from Lira-treated C2C12 cells, Compound C or siAMPKα1, the triglyceride (TG) content and the related gene expression were measured. The transcriptome in irisin-treated differentiated 3T3-L1 cells was analyzed. Lira elevated serum irisin levels, decreased the adipocyte size and increased the protein expression of UCP1, p-AMPK and p-ACC1 in WAT. Moreover, it promoted the expression of PGC1α and FNDC5, the secretion of irisin in PA-treated differentiated C2C12 cells. The irisin and supernatant decreased TG synthesis and promoted the expression of browning- and lipolysis-related genes in differentiated 3T3-L1 cells. While Compound C and siAMPKα1 blocked AMPK activities and expression, irisin partly reversed the pathway. Finally, the transcriptome analysis indicated that differently expressed genes are mainly involved in browning and lipid metabolism. Overall, our findings showed that Lira modulated muscle-to-adipose signaling pathways in diabetes via irisin-mediated AMPKα/ACC1/UCP1/PPARα pathway. Our results suggest a new mechanism for the treatment of T2DM by Lira.

Age changes in the lipid profile of rats against experimental metabolic syndrome

Background. Metabolic syndrome (MS) is characterized by the development of pathogenetic mechanisms that potentiate abdominal obesity and insulin resistance. Obesity is a stimulator of the synthesis of active components of adipose tissue – adipocytes (AT), which leads to numerous metabolic and hemodynamic disorders. The study of pathophysiological mechanisms based on the basis of morphometric and biochemical parameters of blood pressure, taking into account age and gender aspects, is of great topical importance. Purpose – of the study is to identify differences in the morphological and histological parameters of adipocytes against the background of the development of metabolic syndrome in animals of different ages and sexes. Materials and Methods. To achieve the goal, an experimental study was conducted on 108 white rats of the WAG/G Sto population. Each age group consisted of a control (36) and an experimental series (72), where the animals were divided by sex. The 1st group included young immature 3-month-old rats of the control (1K) and experimental (1A) subgroups. Group 2 consisted of 36 sexually mature rats aged 5–6 months, divided into 2 subgroups: control (2K) and experimental (2A). The third group consisted of 36 old rats aged 18 months, divided into the control 3K (12) subgroup (6 old females and 6 old males), and the experimental subgroup 3A – of 12 females and 12 males. Results. The hypodermic tissue of all experimental groups consists of adipocytes, the size, shape and density of which had age and gender differences. In group 1A of both subgroups, the cells had a round and oval shape and were significantly smaller in size compared to groups 2A and 3A. Adipocytes of rats have morphological changes against the background of experimental modeling of MS in taking into account age and gender aspects. It was established that in the group of old animals, hypertrophic processes prevail in BP, against the background of greatly reduced hyperplastic processes. Analyzing and comparing the size of adipose tissue cells between experimental groups 1A, 2A and 3A, the dependence of the increase in the size of adipocytes, which is related to the age of the animal, was noted. Conclusions. Experimental changes in the integrative indicators of AT of rats in the pathogenesis of MS are related to age and sex. An inversely proportional dependence of the decrease in the resistance of adipocytes as the age of the animal increases was noted. The obtained results can be designated as a biological marker that determines the development of obesity against the background of disorders of the systemic inflammatory response and insulin resistance.

Inhibitory Effect of Prickly Ash (Zanthoxylum bungeanum) Seed Kernel Oil on Lipid Metabolism of Grass Carp (Ctenopharyngodon idellus) in High-Fat Diet

To investigate the effect of prickly ash (Zanthoxylum bungeanum) seed kernel oil (PASO) on the lipid metabolism of grass carp (Ctenopharyngodon idellus) under a high-fat diet, PASO were added into two lipid-level (4 g/kg and 8 g/kg) diets to form four isonitrogenous diets: soybean oil (SO), PASO, high-fat soybean oil (HSO), and high-fat prickly ash seed oil (HPASO). A total of 216 healthy grass carp (9.43 ± 0.82 g) were randomly divided into four groups and fed with the four diets, respectively, for 56 days. The result showed that the viscerosomatic index (VSI) and the content of the crude lipid in the hepatopancreas and muscle was significantly higher by oil levels (p < 0.05). The linolenic acid content in the body of the fish significantly increased in PASO and HPASO compared to that in SO and HSO (p < 0.05). The fatty acid composition of the hepatopancreas, intraperitoneal fat, and muscle in four dietary groups was significantly similar to the fatty acid composition in the diets (p < 0.05). More significant fat infiltration and nuclear translocation in the hepatopancreas of fish was found in the HSO group but was decreased in the HPASO group. The adipocyte size in the intraperitoneal fat tissue in the PASO group was significantly lower than that in the SO group (p < 0.05). The relative mRNA expression of the lipogenesis-related genes ppar-γ, cebp-α, and srebp-1c was significantly down-regulated in the PASO group compared with the SO group (p < 0.05), and the mRNA expression of lipolysis-related genes ppar-α and cpt-1 were significantly up-regulated in the PASO group (p < 0.05). In conclusion, dietary PASO showed the function of reducing lipid accumulation in the fish. This reduction might be attributed to the inhibition of the lipogenesis-related genes and the stimulation of the lipolysis-related genes, which were probably modulated by the high content of linolenic acid in PASO.

Abstract 2184: A high-fat diet accelerates early-stage murine pancreatic carcinogenesis by influencing, in part, mesenteric adipose tissue metabolism

Abstract Increased adiposity represents a modifiable risk factor of pancreatic cancer. Multiple preclinical studies have shown that a high-fat and high-sugar diets on the acceleration of pancreatic carcinogenesis, in the context of obesity. However, the impact of diets resembling the omega-6 to omega-3 fatty acid (FA) ratio in a Western-style diet, remains unclear. Furthermore, the role of the mesenteric adipose tissue (MAT) in pancreatic carcinogenesis is poorly characterized. Thus, we aimed to determine the impact of a high-fat diet with a ratio of 9 parts omega-6 FA to each omega-3 FA, on early stages of pancreatic carcinogenesis in a genetically engineered LSL- KrasLSL-G12D; Ptf1aCre/+ (KC) model of pancreatic cancer, with an emphasis on evaluating the contribution of the MAT within the pancreatic microenvironment. For this purpose, cohorts of male and female KC mice (6-8 males and females per diet group) were randomly assigned to either a control diet (CD) group (9:1 of omega-6 FAs to omega-3 FAs) or a high-fat diet (HFD) group (9:1 of omega-6 FAs to omega-3 FAs) and fed their respective diets until three months of age. After eight weeks on their diets, HFD-fed mice had significantly increased body weight, fat mass, and elevated serum leptin levels. Furthermore, HFD-fed mice had increased acinar-to-ductal metaplasia, associated with increased PCNA expression, ERK and STAT3 phosphorylation and elevated pro-tumorigenic immune cell expression compared to CD-fed mice. Although no significant differences in MAT weight or adipocyte size were observed after 8 weeks between the groups, metabolomics analysis of the MAT revealed that HFD-fed mice had significant upregulation of many key metabolites linked to proliferative and inflammatory pathways. For instance, HFD-fed female KC mice had significant differences in α-linolenic acid metabolism and the biosynthesis of unsaturated fatty acids, while male mice had significant differences in arginine biosynthesis, amino acid metabolism, linoleic acid metabolism, and α-linolenic acid metabolism. HFD-fed female mice had a significant increase in α-linolenic acid and linoleic acid in MAT, concurrent with a reduction in inosine 5-monophosphate and α-tocopherol compared to female CD-fed mice. HFD-fed male mice displayed a more pronounced difference in metabolites, including an increase in α-linolenic acid, linoleic acid, malic acid, glutamine, isoleucine, and several other amino acids, with a concurrent reduction in lauric acid and palmitoleic acid compared to male CD-fed mice. In summary, a HFD accelerates pancreatic carcinogenesis through multifaceted mechanisms, including effects on the tumor and surrounding adipose depots. A HFD increases affects MAT metabolism in a sex-dependent manner, that might ultimately promote early-stage progression of pancreatic carcinogenesis. Citation Format: Aya Ead, Joanna Wirkus, Gerardo G. Mackenzie. A high-fat diet accelerates early-stage murine pancreatic carcinogenesis by influencing, in part, mesenteric adipose tissue metabolism [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2184.

Abstract 6632: Adipocyte death drives dormant breast cancer cell reactivation

Abstract Despite significant responses to initial treatments, upwards of 30% of breast cancer patients will experience a recurrence of their disease. Unfortunately, there are few clinical features that predict which patients will recur, relegating patients and their doctors to a wait-and-see approach where they must remain vigilant. Recent studies have reported that the presence of disseminated tumor cells (DTCs) in the bone marrow of early-stage breast cancer patients predicts a higher chance of recurrence and that obese patients experience 35%-40% higher rates of recurrence than lean patients. Interestingly, in addition to increased adipocyte size, obese patients experience higher rates of adipocyte apoptosis, macrophage recruitment to adipocyte tissue, and increased inflammation, shown as the formation of crown-like structures (CLSs). Given the rising prevalence of obesity, the need for mechanistic studies to elucidate its contribution to breast cancer dormancy and recurrence is urgent. To investigate how microenvironmental changes associated with obesity affect breast cancer dormancy, we utilized a well-established syngeneic mouse model of ER+ breast cancer dormancy (D2.0R). We found that D2.0R cells remained dormant in the visceral fat of wildtype mice but were reactivated upon adipocyte death due to obesity or genetic manipulation, and this reactivation required the recruitment of macrophages. To understand why macrophages were recruited to the adipose tissue and how they led to dormant tumor cell reactivation, we profiled the microenvironmental changes in visceral fat using single-cell RNA-sequencing and found that the infiltrating macrophages exhibited unique pro-inflammatory and lipid regulatory phenotypes. Further investigation revealed that macrophages activated the integrin-focal adhesion kinase (FAK) pathway in dormant D2.0R cells and the inhibition of integrin and FAK inhibited this activation. Given tumor cells can metastasize to visceral fat depots in breast cancer patients, our findings provide an important model to determine what drives dormant tumor cell growth in adipose tissue. Our study provides novel insights into how tumor microenvironment (TME) impacts breast cancer dormancy and also highlights the importance of adipose tissue as a unique reservoir that potentiates cancer relapse. Citation Format: Xiaoyu Yuan, Qihao Ren, Sheila A. Stewart. Adipocyte death drives dormant breast cancer cell reactivation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6632.

Black Soldier Fly Oil in Different Lipid Diets Could Regulate Tissue Lipid Metabolism and Fatty Acid Composition of Juvenile Mirror Carp

In the present study, our aim was to assess the effect of dietary black soldier fly oil (BSFO) with different lipid contents on the growth performance, body composition, lipid metabolism, and related gene expression in juvenile mirror carp (Cyprinus carpio var. specularis). An 8-week feeding trial was conducted using four isonitrogenous diets (32.0% crude protein) containing two lipid levels: 6% (control (CT) group) and 9% (high lipid (HL) group), both using soybean oil as the oil source. The other two diets contained BSFO on the basis of 6% and 9% lipid, referred to as (CT + BSFO) and (HL + BSFO) groups. The results showed that final body weight, weight gain rate, specific growth rate, protein retention ratio, and feed utilization were significantly increased by using higher dietary lipid levels (P<0.05). Additionally, the gene expression of lipid synthesis markers was significantly up-regulated in intra-peritoneal fat but significantly down-regulated in the hepatopancreas due to increased dietary lipid level (P<0.05). No negative effects on feed utilization or growth performance were observed in fish fed diets containing BSFO. However, the intra-peritoneal fat index, adipocyte size, and hepatopancreas lipid content were significantly decreased in the CT + BSFO group compared to the CT group (P<0.05). Furthermore, BSFO also up-regulated the expression of lipid lipolysis markers in the hepatopancreas and intra-peritoneal fat (P<0.05). Moreover, the use of BSFO also increased the content of n-3 polyunsaturated fatty acid (PUFA) while reducing the content of n-6 PUFA in the muscle (P<0.05). In conclusion, HL diets improved the growth of the fish and increased the lipid deposition. BSFO in the diet resulted in a reduction of lipid deposition in the hepatopancreas and intra-peritoneal fat, likely due to an increase in lipid oxidation.

Novel Human Milk Fat Substitutes Based on Medium- and Long-Chain Triacylglycerol Regulate Thermogenesis, Lipid Metabolism, and Gut Microbiota Diversity in C57BL/6J Mice.

Human milk is naturally rich in medium- and long-chain triacylglycerols (MLCT), accounting for approximately 30% of the total fat. However, infant formula fat is prepared using a physical blend of vegetable oils, which rarely contains MLCT, similar to human milk. The differences in MLCT between human milk and infant formulas may cause different lipid metabolisms and physiological effects on infants, which are unknown. This study aimed to analyze the metabolic characteristics of formula lipid containing novel human milk fat substitutes based on MLCT (FL-MLCT) and compare their effects with those of the physical blend of vegetable oils (FL-PB) on lipid metabolism and gut microbiota in mice. Compared with the FL-PB group, the FL-MLCT group showed increased energy expenditure, decreased serum triacylglycerol level, and significantly lower aspartate aminotransferase level, epididymal and perirenal fat weight, and adipocyte size. Moreover, the abundances of Firmicutes/Bacteroidota, Actinobacteriota, and Desulfovibrionaceae were significantly decreased in the FL-MLCT group. Novel human milk fat substitutes MLCT could inhibit visceral fat accumulation, improve liver function, and modulate the mice gut microbiota composition, which may contribute to controlling obesity.

Stem cell secretome treatment improves whole-body metabolism, reduces adiposity, and promotes skeletal muscle function in aged mice.

Aging coincides with the progressive loss of muscle mass and strength, increased adiposity, and diminished physical function. Accordingly, interventions aimed at improving muscle, metabolic, and/or physical health are of interest to mitigate the adverse effects of aging. In this study, we tested a stem cell secretome product, which contains extracellular vesicles and growth, cytoskeletal remodeling, and immunomodulatory factors. We examined the effects of 4 weeks of 2×/week unilateral intramuscular secretome injections (quadriceps) in ambulatory aged male C57BL/6 mice (22-24 months) compared to saline-injected aged-matched controls. Secretome delivery substantially increased whole-body lean mass and decreased fat mass, corresponding to higher myofiber cross-sectional area and smaller adipocyte size, respectively. Secretome-treated mice also had greater whole-body physical function (grip strength and rotarod performance) and had higher energy expenditure and physical activity levels compared to control mice. Furthermore, secretome-treated mice had greater skeletal muscle Pax7+ cell abundance, capillary density, collagen IV turnover, reduced intramuscular lipids, and greater Akt and hormone sensitive lipase phosphorylation in adipose tissue. Finally, secretome treatment invitro directly enhanced muscle cell growth and IL-6 production, and in adipocytes, it reduced lipid content and improved insulin sensitivity. Moreover, indirect treatment with secretome-treated myotube culture media also enhanced muscle cell growth and adipocyte size reduction. Together, these data suggest that intramuscular treatment with a stem cell secretome improves whole-body metabolism, physical function, and remodels skeletal muscle and adipose tissue in aged mice.