Larger Adipocytes Research Articles

Morphofunctional characterization of the three main adipose tissue depots in rainbow trout (Oncorhynchus mykiss)

Visceral adipose tissue (VAT) is the primary fat reservoir and energy source in fish. Other relevant fat depots include subcutaneous adipose tissue (SAT), located under epithelial layers, and intramuscular adipose tissue (IMAT), found between the myotomes. The present study investigates the morphological, gene expression and functional characteristics of these different depots in rainbow trout (Oncorhynchus mykiss). Commercial rainbow trout of two different average weights were sampled for histology, lipid quantification and fatty acids profile. Mature adipocytes were isolated for gene expression analyses of lipid metabolic markers. Both VAT and SAT showed large adipocytes, and high total lipid content, suggesting hypertrophic growth. Adipocytes in IMAT were consistently smaller regardless of fish size. While fatty acid composition was similar across depots, SAT had lower levels of palmitic acid and higher levels of polyunsaturated fatty acids that act as precursors of phospholipids and eicosanoids such as eicosapentaenoic acid, compared to VAT and IMAT. Gene expression analyses revealed higher levels of fatty acid transporters, lipolysis and β-oxidation markers in VAT and SAT compared to IMAT, suggesting a more active lipid metabolism. These data support the role of VAT as the main energy depot, while SAT may act as a secondary reservoir, and IMAT potentially serves as an occasional energy source for muscles. This study provides valuable insights into the distinct properties of the different fat depots in fish, which may help to optimize strategies to modulate adiposity for improved health, metabolism, and product quality.

Chromium and Palmitic Acid Supplementation Modulate Adipose Tissue Insulin Sensitivity in Postpartum Dairy Cows

Periparturient dairy cows exhibit intense lipolysis driven by reduced dry matter intake, enhanced energy needs, and the loss of adipose tissue (AT) insulin sensitivity. Extended periods of low insulin sensitivity and negative energy balance induce lipolysis dysregulation, leading to increased disease susceptibility and poor lactation performance. Chromium (Cr) supplementation improves systemic insulin sensitivity, while palmitic acid (PA) increases energy availability for milk production. However, the effect of supplementing Cr and PA alone or in combination on insulin sensitivity in AT is unknown. Thirty-two multiparous cows were used in a randomized complete block design experiment and randomly assigned to one of 4 diets fed from 1 to 24 DIM. Diets included: control, no supplementation (CON, n = 8); Cr (Cr-propionate at 0.45 ppm Cr/kg DM, n = 8); PA (1.5% DM, n = 8); or Cr+PA (n = 8). Plasma samples were collected at -13 ± 5.1 d prepartum (PreP), and 14.4 ± 1.9d (PP1) and 21 ± 1.9d (PP2) after calving for albumin, BHB, BUN, calcium, cholesterol, glucose, nonesterified fatty acids (NEFA), total protein, iron, transferrin, triglycerides, and oxylipids quantification. Subcutaneous AT (SCAT) explants were collected at PreP, PP1 and PP2 and incubated in the presence of the lipolytic agent isoproterenol (ISO = 1 µM, BASAL = 0 µM) for 3 h. The antilipolytic effect of insulin (1µL/L) on SCAT explants was evaluated during ISO stimulation (IN+ISO). Lipolysis was quantified by glycerol release in the media (nmol glycerol/mg AT). Macrophage infiltration and adipocyte size were measured using hematoxylin and eosin-stained AT sections and immunohistochemistry. Cr tended to reduce postpartum NEFA concentrations when compared with CON, PA, and Cr+PA. Likewise, Cr increased the percentage of large adipocytes (>9000 µm2) postpartum compared with other diets. In line with higher lipid content, Cr-fed cows had higher ex-vivo BASAL lipolysis at PP2 when compared with PA and Cr+PA. ISO induced higher lipolysis at PP1 and PP2 but it was not affected by Cr and PA. IN+ISO reduced lipolysis by 29.91 ± 11% in Cr compared with ISO. In contrast, IN+ISO did not affect ISO lipolysis in CON, PA, and Cr+PA. Plasma transferrin was reduced by Cr. At PP2, PA cows had 3.3-fold higher macrophage infiltration in SCAT when compared with CON and Cr. Plasma 9-HODE and 9-oxoODE were increased by Cr+PA. PA increased plasma 13-oxoODE and Cr increased the ratio of 13-HODE:13-oxoODE. PA increased 5-iso Prostaglandin F2α-VI. Our results demonstrate that supplementing Cr during the immediate postpartum enhances SCAT insulin sensitivity and lipid accumulation. Further studies should determine the effects and mechanisms of action of Cr and PA on AT lipogenesis, adipogenesis, and their impact on lactation performance.

Weight gain leads to greater adverse metabolic responses in South Asian compared with white European men: the GlasVEGAS study

South Asians (SAs) develop type 2 diabetes at lower body mass index values than white Europeans (WEs). This basic human experimental study aimed to compare the metabolic consequences of weight gain in SA and WE men without overweight or obesity. Fourteen SAs and 21 WEs had assessments of body composition, metabolic responses to mixed-meal ingestion, cardiorespiratory fitness and physical activity, and a subcutaneous abdominal adipose tissue biopsy, before and after 4–6 weeks of overfeeding to induce 5–7% weight gain. Here we show that body mass index and whole-body adipose tissue volume increases similarly between ethnic groups, but SAs gain less lean tissue. SAs experience a substantially greater decrease in insulin sensitivity compared with WEs (38% versus 7% decrease, P = 0.009), have fewer small (37.1% versus 60.0%, P = 0.003) and more large (26.2% versus 9.1%, P = 0.005) adipocytes at baseline and have a smaller decrease in very small adipocytes with weight gain (−0.1% versus −1.9%, P < 0.0001). Ethnic differences in adipocyte morphology are associated with SA’s greater adverse metabolic changes with weight gain. ClinicalTrials.gov registration: NCT02399423.

Increased capacity to maintain glucose homeostasis in a transgenic mouse expressing human but not mouse growth hormone with developing high-fat diet-related insulin resistance, hepatic steatosis and adipose dysfunction.

The objective was to assess the potential differential effects of human versus mouse growth hormone in vivo, given that human unlike mouse growth hormone can bind prolactin as well as the growth hormone receptor. To this end, a transgenic CD-1 mouse expressing human but not mouse growth hormone was generated, and the phenotypes of male mice fed with a regular chow or high-fat diet were assessed. Pancreas and epididymal white adipose tissue gene expression and/or related function were targeted as the pancreas responds to both prolactin and growth hormone receptor signaling, and catabolic effects like lipolytic activity are more directly attributable to growth hormone and growth hormone receptor signaling. The resulting human growth hormone-expressing mice are smaller than wild-type CD-1 mice, despite higher body fat and larger adipocytes, but both mouse types grow at the same rate with similar bone densities. Unlike wild-type mice, there was no significant delay in glucose clearance in human growth hormone-expressing mice when assessed at 8 versus 24 weeks on a high-fat diet. However, both mouse types showed signs of hepatic steatosis that correlated with elevated prolactin but not growth hormone RNA levels. The larger adipocytes in human growth hormone-expressing mice were associated with modified leptin (higher) and adiponectin (lower) RNA levels. Thus, while limited to observations in the male, the human growth hormone-expressing mice exhibit signs of growth hormone insufficiency and adipocyte dysfunction as well as an initial resistance to the negative effects of high-fat diet on glucose clearance.

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) &gt;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&lt;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&lt;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&lt;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&lt;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.

Abstract 1035: C/EBPα Has Depot-specific Roles In White Adipose Tissue Development And Function.

Obesity, defined as excess white adipose tissue (WAT), associates with a higher risk of metabolic disease and comorbidities, and continues to be on the rise in the developed world. However, different WAT depots associate with differing levels of cardiometabolic risk. Expansion of visceral WAT (vWAT) correlates with increased risk for cardiovascular disease and type 2 diabetes, while expansion of subcutaneous WAT (sWAT) does not. These observations suggest mechanistic differences between the two depots, and elucidating these mechanisms may provide insights into promoting cardiometabolic health in humans. Human GWAS have shown that SNPs near the gene CEBPA associate with waist-to-hip ratio, a metric of vWAT mass in humans, suggesting CEBPA plays a specific role in vWAT. CEBPA encodes the transcription factor C/EBPα, a known regulator of adipogenesis. We established adipocyte-specific Cebpa knockout (Cebpa_ASKO) mice and found they lack gonadal WAT (gWAT), the largest vWAT depot in mice. Conversely, sWAT is still present in Cebpa_ASKO mice, although with reduced mass (-23%, p&lt;0.05) and larger adipocytes. Additionally, Cebpa_ASKO mice have reduced lipolysis (-26% NEFAs, p&lt;0.05), plasma adiponectin (-89%, p&lt;0.0001) and leptin (-82%, p&lt;0.05), suggesting the remaining sWAT is dysfunctional. Together, these data suggest that C/EBPα has WAT depot-specific roles, being required for vWAT development, but only for function in mature sWAT. Given the myriad roles for vWAT in metabolism and the absence of vWAT in Cebpa_ASKO mice, we investigated downstream metabolic consequences of this phenotype. Cebpa_ASKO mice have increased brown adipose tissue (BAT) mass (+118%, p&lt;0.001) due to increased ectopic lipid deposition. Cebpa_ASKO mice also have increases in plasma cholesterol (+20%, p&lt;0.05), liver mass (+24%, p&lt;0.01), and hepatic fat content (+329%, p&lt;0.01). Overall, these results demonstrate that adipocyte C/EBPα significantly influences whole body metabolism. Ongoing studies center on delineating the different mechanisms through which C/EBPα functions in vWAT and sWAT. Understanding the depot-specific mechanisms of C/EBPα could have practical implications for new clinical targets of obesity and metabolic disease.

Differential Modulation by Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA) of Mesenteric Fat and Macrophages and T Cells in Adipose Tissue of Obese fa/fa Zucker Rats.

Polyunsaturated fatty acids (PUFAs) can alter adipose tissue function; however, the relative effects of plant and marine n3-PUFAs are less clear. Our objective was to directly compare the n3-PUFAs, plant-based α-linolenic acid (ALA) in flaxseed oil, and marine-based eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) in high-purity oils versus n6-PUFA containing linoleic acid (LA) for their effects on the adipose tissue and oral glucose tolerance of obese rats. Male fa/fa Zucker rats were assigned to faALA, faEPA, faDHA, and faLA groups and compared to baseline fa/fa rats (faBASE) and lean Zucker rats (lnLA). After 8 weeks, faEPA and faDHA had 11-14% lower body weight than faLA. The oral glucose tolerance and total body fat were unchanged, but faEPA had less mesenteric fat. faEPA and faDHA had fewer large adipocytes compared to faLA and faALA. EPA reduced macrophages in the adipose tissue of fa/fa rats compared to ALA and DHA, while faLA had the greatest macrophage infiltration. DHA decreased (~10-fold) T-cell infiltration compared to faBASE and faEPA, whereas faALA and faLA had an ~40% increase. The n3-PUFA diets attenuated tumour necrosis factor-α in adipose tissue compared to faBASE, while it was increased by LA in both genotypes. In conclusion, EPA and DHA target different aspects of inflammation in adipose tissue.

Visceral adipocyte size links obesity with dysmetabolism more than fibrosis, and both can be estimated by circulating miRNAs.

In obesity, adipocyte hypertrophy is detrimental tohealth, but its' interrelation with fibrosis in the visceral adipose tissue (VAT) depot remains unclear. Because VAT is less accessible via biopsy, biomarkers for VAT quality are needed. The authors hypothesized that VAT adipocyte size and fibrosis are interrelated and can be estimated by circulating microRNAs (circ-miRNAs), contributing to subphenotyping obesity. Adipocyte size and AT fibrosis were estimated in n = 43 participants (BMI ≥ 30 kg/m2 ). Circ-miRNAs were sequenced (Next Generation Sequencing). Participants with above- versus below-median VAT adipocyte area exhibited metabolic dysfunction but lower total and pericellular fibrosis. VAT adipocyte size remained associated with metabolic dysfunction even when controlling for BMI or VAT fibrosis in the entire cohort, as in matched-pairs subanalyses. Next Generation Sequencing uncovered 22 and 6 circ-miRNAs associated with VAT adipocyte size and fibrosis, respectively, with miRNA-130b-3p common to both analyses. The combination of miRNA-130b-3p + miR-150-5p + high-density lipoprotein cholesterol discriminated among those with large versus small VAT adipocytes (receiver operating characteristic-area under the curve: 0.872 [95% CI: 0.747-0.996]), whereas miRNA-130b-3p + miRNA-15a-5p + high-density lipoprotein cholesterol discriminated among those with low and high fibrosis (receiver operating characteristic-area under the curve: 0.823 [95% CI: 0.676-0.97]). These findings suggest that VAT adipocyte size and fibrosis are inversely correlated in obesity and can be estimated by distinct circ-miRNAs, providing a potential tool to subphenotype obesity via a liquid biopsy-like approach to assess VAT health in nonsurgical patients.

Association of adipocyte size and SREBP-1c in visceral and subcutaneous adipose tissue in non-obese type 2 diabetes mellitus.

Non-obese type 2 diabetes seems to be common in India; hence the current study tried to understand the pathogenesis of diabetes in this group focusing on the role of adipocytes especially abdominal fat compartment. Comparison was made between non-obese subjects with newly detected diabetes and those without diabetes, in relation to levels of adipogenic factor and adipokines in pre-adipocytes and mature adipocytes respectively. Non-obese subjects (BMI-18-25 Kg/m2) were consecutively selected of whom 15 had newly-detected, treatment naïve type 2 diabetes (HbA1% ≥6.5) while 25 were control (HbA1c% ≤5.6). We examined the expression of adipocyte differentiation factor - SREBP-1c from preadipocytes and adipocyte specific adipokines- HMW isoform and total adiponectin, leptin, FABP-4, TNF-α and IL-6 from adipocytesisolated from abdominal visceral and subcutaneous adipose tissues (VAT and SCAT) by RT-PCR and as well as from serum by ELISA. Size of cultured adipocytes was measured in a fully automated imaging system microscope. Both in SCAT and VAT, SREBP-1c and adiponectin had significantly lower expression along with increased mRNA level of inflammatory adipokinesdiabetes.Average adipocyte size and frequency of large(hypertrophied) adipocytes were comparatively higher in T2DM subjects and had significant negative correlation with SREBP-1c. HMW adiponectin level significantly reduced in the secretion from VAT and SCAT of T2DM subjects compared to control. Reduced expression of SREBP-1c in preadipocytes may lead to increased number of hypertrophied adipocytes in T2DM. Therefore, these dysfunctional hypertrophied adipocytes could cause imbalanced expression of insulin resistant and insulin sensitive adipokines.

Analysis of MCP-1 Levels and TNF-alfa /Il-10 Ratio in First Degree Relatives (FDR) Type 2 Diabetes Mellitus Subjects with High Fat Diet Treatment

Type 2 diabetes mellitus is a chronic metabolic disease, which involves a variety of pathogenic processes. Overall these processes result in loss of mass and/or function of pancreatic-cells which is manifested as hyperglycemia. The influence of familial factors appears to be involved in the initiation and development of T2DM through both genetic and non-genetic factors. In the same family environment as patients with diabetes, first-degree relatives of patients with diabetes show a 30-70% increased risk of developing diabetes. Insulin resistance and cell dysfunction have been identified in individuals with a family history of diabetes, even before the onset of T2DM symptoms. Monocyte chemoattractant protein-1 (MCP-1) is a CC-chemokine with an attractant effect on monocytes, memory T cells and basophils. Expression of adipose tissue MCP-1 and circulating levels were positively correlated with adiposity. Larger adipocytes are associated with insulin resistance. This study aims to determine the changes in MCP-1 expression on monocytes before and after treatment with a high-fat diet for five days. The results showed that there was a change in inflammatory activity which was indicated by a high ratio of TNF-alfa/IL – 10 in the FDR group so that it could increase MCP-1 activity. However, there was no relationship between serum MCP-1 levels and the percentage of CD14+CD16+ monocytes in both groups.

Programming Mechanism of Adipose Tissue Expansion in the Rat Offspring of Obese Mothers Occurs in a Sex-Specific Manner.

We investigated whether excessive retroperitoneal adipose tissue (AT) expansion programmed by maternal obesity (MO) affects adipocyte size distribution and gene expression in relation to adipocyte proliferation and differentiation in male and female offspring (F1) from control (F1C) and obese (F1MO) mothers. Female Wistar rats (F0) ate a control or high-fat diet from weaning through pregnancy and lactation. F1 were weaned onto a control diet and euthanized at 110 postnatal days. Fat depots were weighed to estimate the total AT. Serum glucose, triglyceride, leptin, insulin, and the insulin resistance index (HOMA-IR) were determined. Adipocyte size and adipogenic gene expression were examined in retroperitoneal fat. Body weight, retroperitoneal AT and adipogenesis differed between male and female F1Cs. Retroperitoneal AT, glucose, triglyceride, insulin, HOMA-IR and leptin were higher in male and female F1MO vs. F1C. Small adipocytes were reduced in F1MO females and absent in F1MO males; large adipocytes were increased in F1MO males and females vs. F1C. Wnt, PI3K-Akt, and insulin signaling pathways in F1MO males and Egr2 in F1MO females were downregulated vs. F1C. MO induced metabolic dysfunction in F1 through different sex dimorphism mechanisms, including the decreased expression of pro-adipogenic genes and reduced insulin signaling in males and lipid mobilization-related genes in females.

Assessment of the physicochemical and sensory characteristics of fermented camel milk fortified with Cordia myxa and its biological effects against oxidative stress and hyperlipidemia in rats.

Natural feed additives and their potential benefits in production of safe and highly nutritious food have gained the attention of many researchers the last decades. Cordia myxa is a nutrient-dense food with various health benefits. Despite this fact, very limited studied investigated the physicochemical and sensory impacts of incorporation of fermented camel milk with Cordia myxa and its biological effects. The current study aimed to assess the physical, chemical, and sensory characteristics of fermented camel milk (FCM) fortified with 5, 10, and 15% Cordia myxa pulp. The study demonstrated that fortification of camel milk efficiently enhanced protein, total solids, ash, fiber, phenolic substance, and antioxidant activity. When compared to other treatments, FCM supplemented with 10% Cordia myxa pulp had the best sensory features. In addition, FCM fortified with 10% Cordia myxa pulp was investigated as a potential inhibitor of hypercholesterolemia agents in obese rats. Thirty-two male Wistar rats were split into two main groups including normal pellet group (n = 8) served as negative control group (G1) and a group of hyperlipidemic animals (n = 24) were feed on a high-fat diet (HFD). Hyperlipidemic rats group (n = 24) were then divided into three subgroups (8 per each); second group or positive control (G2) which include hyperlipidemic rats received distilled water (1 mL/day), the third group (G3) involved hyperlipidemic rats feed on FCM (10 g/day) and the fourth group (G4) included hyperlipidemic animals feed on 10 g/day FCM fortified with 10% of Cordia myxa pulp by oral treatment via an intestinal tube for another 4 weeks. In contrast to the positive control group, G4 treated with Cordia myxa showed a substantial decrease in malondialdehyde, LDL, cholesterol, triglycerides, AST, ALT, creatinine, and urea levels, while a significant increase in HDL, albumin, and total protein concentrations. The number of large adipocytes decreased while the number of small adipocytes increased after consumption of fortified FCM. The results indicated that fermented milk fortified with Cordia myxa pulp improved the functions of the liver and kidney in hyperlipidemic rats. These results demonstrated the protective effects of camel milk and Cordia myxa pulp against hyperlipidemia in rats.

Tissue-like cultured fish fillets through a synthetic food pipeline

Tissue-like cultured meats of some livestock have successfully been established by different approaches. However, the production of a structure similar to fish fillets is still challenging. Here, we develop tissue-like cultured fish fillets by assembly of large yellow croaker muscle fibers and adipocytes with 3D-printed gel. Inhibition of Tgf-β and Notch signals significantly promoted myogenic differentiation of piscine satellite cells (PSCs). The mixture of fish gelatin and sodium alginate combined with a p53 inhibitor and a Yap activator supported PSC viability and proliferation. Based on the texture of fish muscle tissue, a 3D scaffold was constructed by gelatin-based gel mixed with PSCs. After proliferation and differentiation, the muscle scaffold was filled with cultured piscine adipocytes. Finally, tissue-like fish fillets with 20 × 12 × 4 mm were formed, consisting of 5.67 × 107 muscles and 4.02 × 107 adipocytes. The biomanufacture of tissue-like cultured fish fillet here could be a promising technology to customize meat production with high fidelity.

Abstract 5259: Bazedoxifene plus conjugated estrogen improves metabolic health and reduces mammary gland epithelial proliferation in an ovary intact rat model of obesity and breast cancer risk

Abstract Background: The majority of women risk eligible for primary breast cancer prevention with tamoxifen or aromatase inhibitors refuse uptake due to concerns about side effects, especially vasomotor symptoms. Tamoxifen may also have detrimental metabolic effects in overweight/obese women. Duavee™, a complex of bazedoxifene (BZA) and conjugated estrogen (CE), is FDA approved for relief of hot-flashes and prevention of osteoporosis. Preclinical studies suggest favorable metabolic effects in ovariectomized animals and potential for breast cancer risk reduction. A single arm clinical trial found reduction in Ki-67 and mammographic density such that BZA+CE is being further evaluated in a Phase IIB trial of peri and early postmenopausal women with vasomotor symptoms who are at high risk for breast cancer. Here, in a companion study, we assessed the effect of BZA+ CE on metabolic health and cancer risk in a rat model of carcinogen induced ER+ tumors and high fat diet induced obesity. Methods: Rats received 50 mg/kg N-methylnitrosourea at 7 weeks to increase mammary tumor risk and were fed a high fat diet (46% kcal fat) to promote obesity. At 16 weeks lean and obese rat were selected based on % body fat and were then randomized to 8 weeks of daily oral vehicle control or 3mg BZA + 0.07mg CE/kg body weight. Systemic metabolic variables were measured at 16 and 24 weeks, and RNA from mammary glands analyzed by gene expression microarray (Affymetrix). Results: BZA+CE resulted in systemic as well as mammary changes indicative of improved metabolic health, including: reduction in total and visceral fat (p&amp;lt;0.01), glucose (p&amp;lt;0.05), cholesterol (p&amp;lt;0.001), and triglycerides(p=0.08), as well as an increase in the adiponectin:leptin ratio (p&amp;lt;0.01). BZA+CE vs control increased the ratio of small (insulin sensitive) to large adipocytes in the mammary gland. Gene set enrichment analysis (GSEA) showed BZA+CE downregulated proliferation-associated pathways which had been upregulated in obese rats, consistent with anti-cancer effects. Obese rats treated with BZA+CE also had upregulation of metabolic pathways, including adipocyte differentiation, fatty acid metabolism, and inflammatory response pathways. Conclusions: Unlike tamoxifen, BZA+CE improved whole body and mammary gland metabolic health, particularly in obese rats. Transcriptional profiling and GSEA demonstrated a blunting of cell cycle and proliferation and enrichment of metabolic and immune-related pathways. Together this supports BZA+CE (Duavee) as an agent to be explored for breast cancer risk reduction in obese individuals. Funding: This work was supported in part by P30 CA168524, R00 CA169430, and R25 CA203650. Citation Format: Ramsey M. Jenschke, Karen A. Corleto, Carol J. Fabian, Stephen D. Hursting, Bruce F. Kimler, Danilo Landrock, Tara N. Mahmood, Katherine L. Cook, Erin D. Giles. Bazedoxifene plus conjugated estrogen improves metabolic health and reduces mammary gland epithelial proliferation in an ovary intact rat model of obesity and breast cancer risk. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5259.

Abstract P3-05-28: Impact of increased adiposity on extended aromatase inhibitor treatment in postmenopausal patients with estrogen receptor positive (ER+) breast cancer: a retrospective analysis of the SOLE trial

Abstract Background: The risk of late distant recurrence (≥ 5 years) in post-menopausal patients with ER+ BC remains significant even after standard adjuvant endocrine therapy (ET). Obesity, which has reached high proportions in Western Countries, is one of the modifiable factors that can contribute to BC recurrences. While body mass index (BMI) is an easily available surrogate measure of adiposity, it might not reflect accurately patient adiposity, especially in post-menopausal patients. We therefore hypothesize that mammary adipocyte measurements might better capture the adiposity of the patient. In this study, we retrospectively evaluated the prognostic role of both BMI and adipocyte measurements in the SOLE trial. Patients &amp; Methods: The SOLE trial (NCT00553410) consisted of 4,884 postmenopausal women with hormone receptor positive, lymph node-positive BC treated with 5 years of letrozole after having completed 4-6 years of adjuvant ET. BMI was available for 3,606 patients with ER+/HER2- BC and categorized according to the WHO classification (underweight: &amp;lt; 18.5, normal weight 18.5 – 24.9, overweight 25 – 29.9, obesity ≥ 30 kg/m2). Considering the small sample size, patients with underweight (n=35) were grouped together with patients with normal weight for the subsequent analyses. We evaluated the association between clinico-pathological characteristics and BMI using Fisher exact test and Kruskal-Wallis test. Given the previously reported association of BMI with distant recurrences (PMID: 21115856), we considered distant-relapse free interval (DRFI) as the main study endpoint. Cox regression analyses were adjusted for histology, chemotherapy (yes/no), type of local therapy, in addition to previously reported clinico-pathological variables (PMID: 29158011). Then, we conducted a stratified case-cohort study consisting of 311 patients (97 with distant relapse-cases) with successful digital assessment of adipocytes on normal mammary adipose tissue sample collected at surgery, as previously described (PMID: 33120083). Stratification factors were treatment arm and type of prior ET. Weighted Cox regression models (PMID: 17554753, 18712477) were used to evaluate prognostic association with adipocyte size (area in µm²) categorized in quartile of the 75th percentile (Q4 vs Q1-3), as done previously (PMID: 33753731). Results: 1392 (39%) patients were normal weight, 1315 (36%) were overweight and 899 (25%) were obese. Older age at diagnosis, lymph node involvement (≥4), large tumor size and menopausal status were associated with overweight and obesity. After a median follow-up of 84 months, no associations were found between DRFI and BMI in the univariable and multivariable analysis (adjusted HR overweight vs normal=0.99, 95%CI: 0.76 – 1.29, p=0.977 and HR obese vs normal=1.11, 95%CI: 0.84 - 1.47, p=0.425). In the case-cohort study, patients with larger adipocytes had an increased hazard of distant recurrence in the univariable and multivariable analysis (see table 1). Conclusion: In this study, we did not detect any association between BMI and survival outcomes. We however found that larger mammary adipocytes were independently associated with an increased hazard of distant recurrence. These results suggest that mammary adipocytes, which can be easily evaluated on H&amp;E slides using digital pathology, should be considered as a novel marker to evaluate the risk of late recurrence in patients with breast cancer. Citation Format: Edoardo Isnaldi, François Richard, Giuseppe Marano, Patrizia Boracchi, Marion Maetens, Giuseppe Floris, Guy Jerusalem, Andrea Gombos, Alastair M. Thompson, Erika Hitre, Stefan Aebi, Marco Colleoni, Patrizia Dell’Orto, Roswitha Kammler, Patrick Neven, Giuseppe Viale, Meredith Regan, Elia Biganzoli, Christine Desmedt. Impact of increased adiposity on extended aromatase inhibitor treatment in postmenopausal patients with estrogen receptor positive (ER+) breast cancer: a retrospective analysis of the SOLE trial [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-05-28.

Impaired white adipose tissue fatty acid metabolism in mice fed a high-fat diet worsened by arsenic exposure, primarily affecting retroperitoneal adipose tissue

Fatty acid (FA) metabolism dysfunction of white adipose tissue (WAT) underlies obesity and insulin resistance in response to high calorie intake and/or endocrine-disrupting chemicals (EDCs), among other factors. Arsenic is an EDC that has been associated with metabolic syndrome and diabetes. However, the combined effect of a high-fat diet (HFD) and arsenic exposure on WAT FA metabolism has been little studied.FA metabolism was evaluated in visceral (epididymal and retroperitoneal) and subcutaneous WAT of C57BL/6 male mice fed control or HFD (12 and 40% kcal fat, respectively) for 16 weeks together with an environmentally relevant chronic arsenic exposure through drinking water (100 μg/L) during the second half of the study.In mice fed HFD, arsenic potentiated the increase of serum markers of selective insulin resistance in WAT and fatty acid re-esterification and the decrease of the lipolysis index. Retroperitoneal was the WAT most affected, where the combination of arsenic and HFD in contrast to HFD, generated higher adipose weight, larger adipocytes, increased triglyceride content, and decreased fasting stimulated lipolysis evidenced by lower phosphorylation of HSL and perilipin. At the transcriptional level, arsenic in mice fed either diet downregulated genes involved in fatty acid uptake (LPL, CD36), oxidation (PPARα, CPT1), lipolysis (ADRß3) and glycerol transport (AQP7 and AQP9). Additionally, arsenic potentiated hyperinsulinemia induced by HFD, despite a slight increase in weight gain and food efficiency.Thus, the second hit of arsenic in sensitized mice by HFD worsens fatty acid metabolism impairment in WAT, mainly retroperitoneal, along with an exacerbated insulin resistance phenotype.

Crosstalk between Adipose Tissue and Hepatic Mitochondria in the Development of the Inflammation and Liver Injury during Ageing in High-Fat Diet Fed Rats.

Obesity is considered an epidemic disorder, due to an imbalance between energy consumption and metabolizable energy intake. This balance is increasingly disrupted during normal aging processes due to the progressive impairment of mechanisms that normally control energy homeostasis. Obesity is triggered by an excessive lipid depots but reflects systemic inflammation along with large adipocytes secreting proinflammatory adipokines, an increase of the free fatty acids levels in the bloodstream, and ectopic lipid accumulation. Hepatic fat accumulation is the most common cause of chronic liver disease, characterized by mitochondrial dysfunction with a consequent impaired fat metabolism and increased oxidative stress. Therefore, mitochondrial dysfunction is associated to hepatic lipid accumulation and related complications. In this study, we assessed the crosstalk between adipose tissue and liver, analyzing the time-course of changes in hepatic mitochondrial fatty acid oxidation capacity versus fatty acid storage, focusing on the contribution of adipose tissue inflammation to hepatic lipid accumulation, using a rodent model of high fat diet-induced obesity. Our results demonstrate that both high-fat diet-induced obesity and aging induce dysregulation of adipose tissue function and similar metabolic alterations mediated by mitochondrial function impairment and altered inflammatory profile. The high fat diet-induced obesity anticipates and exacerbates liver mitochondrial dysfunction that occurs with aging processes.

Growth hormone stimulates lipolysis in mice but not in adipose tissue or adipocyte culture.

The inhibitory effect of growth hormone (GH) on adipose tissue growth and the stimulatory effect of GH on lipolysis are well known, but the mechanisms underlying these effects are not completely understood. In this study, we revisited the effects of GH on adipose tissue growth and lipolysis in the lit/lit mouse model. The lit/lit mice are GH deficient because of a mutation in the GH releasing hormone receptor gene. We found that the lit/lit mice had more subcutaneous fat and larger adipocytes than their heterozygous lit/+ littermates and that these differences were partially reversed by 4-week GH injection. We also found that GH injection to the lit/lit mice caused the mature adipose tissue and adipocytes to reduce in size. These results demonstrate that GH inhibits adipose tissue growth at least in part by stimulating lipolysis. To determine the mechanism by which GH stimulates lipolysis, we cultured adipose tissue explants and adipocytes derived from lit/lit mice with GH and/or isoproterenol, an agonist of the beta-adrenergic receptors. These experiments showed that whereas isoproterenol, expectedly, stimulated potent lipolysis, GH, surprisingly, had no effect on basal lipolysis or isoproterenol-induced lipolysis in adipose tissue explants or adipocytes. We also found that both isoproterenol-induced lipolysis and phosphorylation of hormone-sensitive lipase were not different between lit/lit and lit/+ mice. Taken together, these results support the conclusion that GH has lipolytic effect in mice but argue against the notion that GH stimulates lipolysis by directly acting on adipocytes or by enhancing β-adrenergic receptors-mediated lipolysis.

GLUT4 translocation and dispersal operate in multiple cell types and are negatively correlated with cell size in adipocytes

The regulated translocation of the glucose transporter, GLUT4, to the surface of adipocytes and muscle is a key action of insulin. This is underpinned by the delivery and fusion of GLUT4-containing vesicles with the plasma membrane. Recent studies have revealed that a further action of insulin is to mediate the dispersal of GLUT4 molecules away from the site of GLUT4 vesicle fusion with the plasma membrane. Although shown in adipocytes, whether insulin-stimulated dispersal occurs in other cells and/or is exhibited by other proteins remains a matter of debate. Here we show that insulin stimulates GLUT4 dispersal in the plasma membrane of adipocytes, induced pluripotent stem cell-derived cardiomyocytes and HeLa cells, suggesting that this phenomenon is specific to GLUT4 expressed in all cell types. By contrast, insulin-stimulated dispersal of TfR was not observed in HeLa cells, suggesting that the mechanism may be unique to GLUT4. Consistent with dispersal being an important physiological mechanism, we observed that insulin-stimulated GLUT4 dispersal is reduced under conditions of insulin resistance. Adipocytes of different sizes have been shown to exhibit distinct metabolic properties: larger adipocytes exhibit reduced insulin-stimulated glucose transport compared to smaller cells. Here we show that both GLUT4 delivery to the plasma membrane and GLUT4 dispersal are reduced in larger adipocytes, supporting the hypothesis that larger adipocytes are refractory to insulin challenge compared to their smaller counterparts, even within a supposedly homogeneous population of cells.