Normal Adipose Tissue Research Articles

Non-shivering Thermogenesis Signalling Regulation and Potential Therapeutic Applications of Brown Adipose Tissue.

In mammals, thermogenic organs exist in the body that increase heat production and enhance energy regulation. Because brown adipose tissue (BAT) consumes energy and generates heat, increasing energy expenditure via BAT might be a potential strategy for new treatments for obesity and obesity-related diseases. Thermogenic differentiation affects normal adipose tissue generation, emphasizing the critical role that common transcriptional regulation factors might play in common characteristics and sources. An understanding of thermogenic differentiation and related factors could help in developing ways to improve obesity indirectly or directly through targeting of specific signalling pathways. Many studies have shown that the active components of various natural products promote thermogenesis through various signalling pathways. This article reviews recent major advances in this field, including those in the cyclic adenosine monophosphate-protein kinase A (cAMP-PKA), cyclic guanosine monophosphate-GMP-dependent protein kinase G (cGMP-AKT), AMP-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), transforming growth factor-β/bone morphogenic protein (TGF-β/BMP), transient receptor potential (TRP), Wnt, nuclear factor-κ-light-chain-enhancer of activated B cells (NF-κΒ), Notch and Hedgehog (Hh) signalling pathways in brown and brown-like adipose tissue. To provide effective information for future research on weight-loss nutraceuticals or drugs, this review also highlights the natural products and their active ingredients that have been reported in recent years to affect thermogenesis and thus contribute to weight loss via the above signalling pathways.

Impact of Obesity-Related Inflammation on Cardiac Metabolism and Function.

This review focuses on the role of adipose tissue in obese individuals in the development of metabolic diseases, and their consequences for metabolic and functional derangements in the heart. The general idea is that the expansion of adipocytes during the development of obesity gives rise to unhealthy adipose tissue, characterized by low-grade inflammation and the release of proinflammatory adipokines and fatty acids (FAs). This condition, in turn, causes systemic inflammation and elevated FA concentrations in the circulation, which links obesity to several pathologies, including impaired insulin signaling in cardiac muscle and a subsequent shift in myocardial substrate oxidation in favor of FAs and reduced cardiac efficiency. This review also argues that efforts to prevent obesity-related cardiometabolic disease should focus on anti-obesogenic strategies to restore normal adipose tissue metabolism.

Towards reference values of pericoronary adipose tissue attenuation: impact of coronary artery and tube voltage in coronary computed tomography angiography

ObjectivesTo determine normal pericoronary adipose tissue mean attenuation (PCATMA) values for left the anterior descending (LAD), left circumflex (LCX), and right coronary artery (RCA) in patients without plaques on coronary CT angiography (cCTA), taking into account tube voltage influence.MethodsThis retrospective study included 192 patients (76 (39.6%) men; median age 49 years (range, 19–79)) who underwent cCTA with third-generation dual-source CT for the suspicion of CAD between 2015 and 2017. We selected patients without plaque on cCTA. PCATMA was measured semi-automatically on cCTA images in the proximal segment of the three main coronary arteries with 10 mm length. Paired t-testing was used to compare PCATMA between combinations of two coronary arteries within each patient, and one-way ANOVA testing was used to compare PCATMA in different kV groups.ResultsThe overall mean ± standard deviation (SD) PCATMA was − 90.3 ± 11.1 HU. PCATMA in men was higher than that in women: − 88.5 ± 10.5 HU versus − 91.5 ± 11.3 HU (p = 0.001). PCATMA of LAD, LCX, and RCA was − 92.4 ± 11.6 HU, − 88.4 ± 9.9 HU, and − 90.2 ± 11.4 HU, respectively. Pairwise comparison of the arteries showed significant difference in PCATMA: LAD and LCX (p < 0.001), LAD and RCA (p = 0.009), LCX and RCA (p = 0.033). PCATMA of the 70 kV, 80 kV, 90 kV, 100 kV, and 120 kV groups was − 95.6 ± 9.6 HU, − 90.2 ± 11.5 HU, − 87.3 ± 9.9 HU, − 82.7 ± 6.2 HU, and − 79.3 ± 6.8 HU, respectively (p < 0.001).ConclusionsIn patients without plaque on cCTA, PCATMA varied by tube voltage, with minor differences in PCATMA between coronary arteries (LAD, LCX, RCA). PCATMA values need to be interpreted taking into account tube voltage setting.Key Points• In patients without plaque on cCTA, PCATMAdiffers slightly by coronary artery (LAD, LCX, RCA).• Tube voltage of cCTA affects PCATMAmeasurement, with mean PCATMAincreasing linearly with increasing kV.• For longitudinal cCTA analysis of PCATMA, the use of equal kV setting is strongly recommended.

Inositol polyphosphate multikinase in adipocytes is dispensable for regulating energy metabolism and whole body metabolic homeostasis.

Adipose tissue plays a central role in regulating whole body energy and glucose homeostasis at both organ and systemic levels. Inositol polyphosphates, such as 5-diphosphoinositol pentakisphosphate, reportedly control adipocyte functions and energy expenditure. However, the physiological roles of the inositol polyphosphate (IP) pathway in the adipose tissue are not yet fully defined. The aim of the present study was to test the hypothesis that inositol polyphosphate multikinase (IPMK), a key enzyme in the IP metabolism, plays a critical role in adipose tissue biology and obesity. We generated adipocyte-specific IPMK knockout (Ipmk AKO) mice and evaluated metabolic phenotypes by measuring fat accumulation, glucose homeostasis, and insulin sensitivity in adult mice fed either a regular-chow diet or high-fat diet (HFD). Despite substantial reduction of IPMK, Ipmk AKO mice exhibited normal glucose tolerance and insulin sensitivity and did not show changes in fat accumulation in response to HFD-feeding. In addition, loss of IPMK had no major impact on thermogenic processes in response to cold exposure. Collectively, these findings suggest that adipocyte IPMK is dispensable for normal adipose tissue and its physiological functions in whole body metabolism, suggesting the complex roles that inositol polyphosphate metabolism has in the regulation of adipose tissue.

Influence of breast cancer risk factors and intramammary biotransformation on estrogen homeostasis in the human breast

Understanding intramammary estrogen homeostasis constitutes the basis of understanding the role of lifestyle factors in breast cancer etiology. Thus, the aim of the present study was to identify variables influencing levels of the estrogens present in normal breast glandular and adipose tissues (GLT and ADT, i.e., 17β-estradiol, estrone, estrone-3-sulfate, and 2-methoxy-estrone) by multiple linear regression models. Explanatory variables (exVARs) considered were (a) levels of metabolic precursors as well as levels of transcripts encoding proteins involved in estrogen (biotrans)formation, (b) data on breast cancer risk factors (i.e., body mass index, BMI, intake of estrogen-active drugs, and smoking) collected by questionnaire, and (c) tissue characteristics (i.e., mass percentage of oil, oil%, and lobule type of the GLT). Levels of estrogens in GLT and ADT were influenced by both extramammary production (menopausal status, intake of estrogen-active drugs, and BMI) thus showing that variables known to affect levels of circulating estrogens influence estrogen levels in breast tissues as well for the first time. Moreover, intratissue (biotrans)formation (by aromatase, hydroxysteroid-17beta-dehydrogenase 2, and beta-glucuronidase) influenced intratissue estrogen levels, as well. Distinct differences were observed between the exVARs exhibiting significant influence on (a) levels of specific estrogens and (b) the same dependent variables in GLT and ADT. Since oil% and lobule type of GLT influenced levels of some estrogens, these variables may be included in tissue characterization to prevent sample bias. In conclusion, evidence for the intracrine activity of the human breast supports biotransformation-based strategies for breast cancer prevention. The susceptibility of estrogen homeostasis to systemic and tissue-specific modulation renders both beneficial and adverse effects of further variables associated with lifestyle and the environment possible.

New Role for Growth/Differentiation Factor 15 in the Survival of Transplanted Brown Adipose Tissues in Cooperation with Interleukin-6.

To identify factors involved in the earliest phase of the differentiation of human embryonic stem cells (hESCs) into brown adipocytes (BAs), we performed multi-time point microarray analyses. We found that growth/differentiation factor 15 (GDF15) expressions were specifically upregulated within three days of differentiation, when expressions of immature hESC markers were sustained. Although GDF15 expressions continued to increase in the subsequent differentiation phases, GDF15-deficient hESCs differentiated into mature BAs (Day 10) without apparent abnormalities. In addition, GDF15-deficient mice had normal brown adipose tissue (BAT) and were metabolically healthy. Unexpectedly, we found that interleukin-6 (IL6) expression was significantly lowered in the BAT of GDF15-/- mice. In addition, GDF15-/- hESCs showed abortive IL6 expressions in the later phase (>Day 6) of the differentiation. Interestingly, GDF15 expression was markedly repressed throughout the whole course of the differentiation of IL6-/- hESCs into BAs, indicating IL6 is essential for the induction of GDF15 in the differentiation of hESCs. Finally, intraperitoneally transplanted BAT grafts of GDF15-/- donor mice, but not those of wild-type (WT) mice, failed in the long-term survival (12 weeks) in GDF15-/- recipient mice. Collectively, GDF15 is required for long-term survival of BAT grafts by creating a mutual gene induction loop with IL6.

Measurement of the AST to LD Ratio in Parathyroid Tissue Suspension Can Precisely Differentiate a Hyperfunctioning Parathyroid.

Frozen section of excised tissue is used to confirm removal of the etiology of primary hyperparathyroidism in the current era of intraoperative parathyroid hormone measurement and provides safeguards for surgeons. We recently reported that the aspartate aminotransferase (AST)/lactate dehydrogenase (LD) ratio in tissue suspension can accurately distinguish normal parathyroid tissue from other tissues. Therefore, we hypothesized that this ratio may also be applied to distinguish hyperfunctioning parathyroid tissue (HPT) from other tissues. We prospectively analyzed 22 patients who underwent parathyroidectomy for primary hyperparathyroidism (benign, 21; malignant, 1) from July 2018 to October 2019. In total, 27 specimens were examined. Approximately 1 mm3 of minced HPT as confirmed by frozen sections was suspended in 1 mL of normal saline and AST and LD levels were measured. The AST/LD ratios of other tissues (normal parathyroid tissue, thyroid gland, adipose tissue, and others; n = 94) were obtained from our previous report. The AST/LD ratio of benign HPT was consistently higher than that of other tissues (P < 0.001). The optimal cut-off value was 0.36 according to the receiver operating characteristic curve, with 100% sensitivity and specificity. The AST/LD ratio in malignant HPT was also markedly lower than that in benign HPT. This method might be a new adjunct for intraoperative differentiation of HPT with an accuracy and turnaround time comparable with those of frozen sections, minimal cost, and no need for dedicated pathological staff. Additionally, this method might increase the treatment success rate in settings with limited medical resources.

ADSC-Exos containing MALAT1 promotes wound healing by targeting miR-124 through activating Wnt/β-catenin pathway.

Cutaneous wound is a soft tissue injury that is difficult to heal during aging. It has been demonstrated that adipose-derived stem cells (ADSCs) and its secreted exosomes exert crucial functions in cutaneous wound healing. The present study aimed to elucidate the mechanism of exosomes derived from ADSCs (ADSC-Exos) containing MALAT1 in wound healing. ADSCs were isolated from human normal subcutaneous adipose tissues and identified by flow cytometry analysis. Exosomes were extracted from ADSC supernatants and MALAT1 expression was determined using qRT-PCR analysis. HaCaT and HDF cells were exposed to hydrogen peroxide (H2O2) for simulating the skin lesion model. Subsequently, CCK-8, flow cytometry, wound healing and transwell assays were employed to validate the role of ADSC-Exos containing MALAT1 in the skin lesion model. Besides, cells were transfected with sh-MALAT1 to verify the protective role of MALAT1 in wound healing. The binding relationship between MALAT1 and miR-124 were measured by dual-luciferase reporter assay. ADSC-Exos promoted cell proliferation, migration, and inhibited cell apoptosis of HaCaT and HDF cells impaired by H2O2. However, the depletion of MALAT1 in ADSC-Exos lose these protective effects on HaCaT and HDF cells. Moreover, miR-124 was identified to be a target of MALAT1. Furthermore, ADSC-Exos containing MALAT1 could mediate H2O2-induced wound healing by targeting miR-124 and activating Wnt/β-catenin pathway. ADSC-Exos containing MALAT1 play a positive role in cutaneous wound healing possibly via targeting miR-124 through activating the Wnt/β-catenin pathway, which may provide novel insights into the therapeutic target for cutaneous wound healing.

SAT-018 Androgen Actions in Adipose Tissue and the Brain Are Key Mediators in the Development of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a complex disorder characterised by endocrine, reproductive and metabolic abnormalities. Despite PCOS being the most common endocrinopathy affecting women of reproductive age, its etiology is poorly understood so there is no cure and symptom-oriented treatment is suboptimal. Elucidation of the underlying mechanisms involved in the pathogenesis of PCOS would pave the way for the development of new interventions for PCOS. Hyperandrogenism is the most consistent feature observed in PCOS patients, and recently aberrant neuroendocrine signalling and adipose tissue function have been proposed as playing a pathogenic role in the development of experimental PCOS. To investigate the role of adipose tissue and the brain as potential key sites for androgen receptor (AR)-mediated development of PCOS, we combined an adipocyte and brain-specific ARKO knockout (AdBARKO) mouse model with a dihydrotestosterone (DHT)-induced mouse model of PCOS. Wildtype (WT) and AdBARKO prepubertal mice were implanted with a blank or DHT implant and examined after 12 weeks. In WT control females, DHT exposure induced the PCOS reproductive traits of cycle irregularity, ovulatory dysfunction and reduced follicle health. In contrast, these reproductive features of PCOS were absent in DHT-treated AdBARKO females. The PCOS metabolic characteristics of increased adiposity, adipocyte hypertrophy and hepatic steatosis were induced by DHT in WT females. Despite DHT treatment, AdBARKO females displayed normal white adipose tissue weight, and adipocyte hypertrophy and hepatic steatosis were not evident. However, as with WT mice, DHT treatment induced increased fasting glucose levels in AdBARKO females. These results demonstrate that adipose tissue and the brain are key loci for androgen-mediated actions involved in the developmental origins of PCOS. These findings support targeting adipocyte and neuroendocrine AR-driven pathways in the future development of novel therapeutic strategies for PCOS.

The Construction and Analysis of the Aberrant lncRNA-miRNA-mRNA Network in Adipose Tissue from Type 2 Diabetes Individuals with Obesity.

Background The prevalence of obesity and type 2 diabetes mellitus (T2DM) has become the most serious global public health issue. In recent years, there has been increasing attention to the role of long noncoding RNAs (lncRNAs) in the occurrence and development of obesity and T2DM. The aim of this work was to find new lncRNAs as potential predictive biomarkers or therapeutic targets for obesity and T2DM. Methods In this study, we identified significant differentially expressed mRNAs (DEmRNAs) and differentially expressed lncRNAs (DElncRNAs) between adipose tissue of individuals with obesity and T2DM and normal adipose tissue (absolute log2FC ≥ 1 and FDR < 0.05). Then, the lncRNA-miRNA interactions predicted by miRcode were further screened with a threshold of MIC > 0.2. Simultaneously, the mRNA-miRNA interactions were explored by miRWalk 2.0. Finally, a ceRNA network consisting of lncRNAs, miRNAs, and mRNAs was established by integrating lncRNA-miRNA interactions and mRNA-miRNA interactions. Results Upon comparing adipose tissue from individuals with obesity and T2DM and normal adipose tissues, 364 significant DEmRNAs, including 140 upregulated and 224 downregulated mRNAs, were identified in GSE104674; in addition, 231 significant DEmRNAs, including 146 upregulated and 85 downregulated mRNAs, were identified in GSE133099. GO and KEGG analyses have shown that downregulated DEmRNAs in GSE104674 and GSE133099 were associated with obesity- and T2DM-related biological pathways, such as lipid metabolism, AMPK signaling, and insulin resistance. Furthermore, 28 significant DElncRNAs, including 14 upregulated and 14 downregulated lncRNAs, were found. Based on the predicted lncRNA-miRNA and mRNA-miRNA relationships, we constructed a competitive endogenous RNA (ceRNA) network, including five lncRNAs, ten miRNAs, and 15 mRNAs. KEGG-GSEA analysis revealed that four lncRNAs (FLG-AS1, SNAI3-AS1, AC008147.0, and LINC02015) in the ceRNA network were related to the biological pathways of metabolic diseases. Conclusions Through ceRNA network analysis, our study identified four new lncRNAs that may be used as potential biomarkers and therapeutic targets of obesity and T2DM, thus laying a foundation for future clinical studies.

Toward noninvasive quantification of adipose tissue oxygenation with MRI.

Molecular oxygen (O2) plays a key role in normal and pathological adipose tissue function, yet technologies to measure its role in adipose tissue function are limited. O2 is paramagnetic and, in principle, directly influences the magnetic resonance (MR) 1H longitudinal relaxation rate constant of lipids, R1; thus, we hypothesize that MR imaging (MRI) can directly measure adipose O2 via a simple measure of R1. R1 was measured in a 4.7T preclinical MRI system at discrete oxygen partial pressure (pO2) levels. These measures were made in vitro in an idealized system and in vivo in subcutaneous and visceral white adipose of rodents. pO2 was determined using an invasive fiber-optic oxygen monitor. From the MRI and fiber optic data we determined the "relaxivity" of O2 in lipid, a critical parameter in converting the MRI-based R1 measurement into pO2. We used breathing gas challenge to estimate the changes in lipid pO2 (ΔpO2). The relaxivity of O2 in lipid was determined to be 1.7·10-3 ± 4·10-4 mmHg-1s-1 at 4.7T and 37 °C, and was consistent between in vitro and in vivo adipose tissue. There was a strong, significant correlation between MRI- and gold standard OxyLite-based measurements of lipid ΔpO2 for in vivo visceral and subcutaneous fat depots in rodents. This study lays the foundation for a direct, noninvasive measure of adipose pO2 using MRI and will allow for noninvasive measurement of O2 flux in adipose tissue. The proposed approach would be of particular importance in the interrogation of the pathogenesis of type 2 diabetes, where it has been suggested that adipose tissue hypoxia is an independent driver of insulin resistance pathway.

The effect of Lysimachia savranii on the breast canser cells in cell culture conditions compared to normal cells

The breast cancer has become a threat to women's lives at an increasing rate. The inadequate treatments of surgical procedures and chemotherapy affect negatively quality of patient life. Therefore, there has been an increase in demand for alternative and supportive agents, especially for the use of herbal products. The purpose of this study is to evaluate the in vitro anti-tumor activity of Lysimachia savranii in breast cancer cell lines compared to normal adipose tissue derived mesenchymal stem cells. The adipose tissue derived mesenchymal stem cells as normal cells with MCF-7 and, MDA-MB-231 breast cancer cells were cultured. IC50 doses of Lysimachia savranii extract for each cells were determined via MTT assay. The immunocytochemical staining was performed for the oxidative stress by eNOS, whereas apoptosis were analyzed by TUNEL method. The data exhibited with H-score and apoptotic index. The plant extract inhibited the proliferation and survival in the breast cancer cells compared to the stem cells. Lysimachia savranii extract caused the increase of eNOS staining for oxidative stress and the TUNEL labeling for apoptosis. The further molecular techniques should be used to determine the biologic activity of Lysimachia savranii extract and its content should be investigated.

Histology and molecular biology studies on the expression and localization of angiopoietin-like protein 8 in human tissues.

Angiopoietin-like protein (ANGPTL) 8 regulates the partitioning of triglycerides by inhibiting lipoprotein lipase in muscle and adipose tissues. ANGPTL8 is expressed in the liver and adipose tissue and secreted into the blood. However, the precise localization of ANGPTL8-expressing cells in these tissues remains unknown. The aim of the present study was to investigate the localization of ANGPTL8-expressing cells in human tissues. Using formalin-fixed paraffin-embedded human tissue specimens, the expression of ANGPTL8 was investigated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), immunohistochemistry (IHC) and in situ hybridization (ISH). The expression level of ANGPTL8 mRNA was the highest in the liver, followed by lipoma, hibernoma and normal adipose tissue. In the liver, wild type (KF809856) and two splice variants of ANGPTL8 mRNA (KF809857 and KF809858) were found to be expressed. The expression level of the splice variant KF809858, which produces a short form of ANGPTL8, accounted for <1% of ANGPTL8 in the liver. IHC revealed that ANGPTL8 was expressed in hepatocytes in zone 1 of the hepatic acinus in the liver. In the adipose tissue, mature adipocytes weakly expressed ANGPTL8, while immature adipocytes strongly expressed it. ISH confirmed ANGPTL8 mRNA expression in portal hepatocytes and immature adipocytes. ANGPTL8 was expressed in the cells, which actively uptake and metabolize triglycerides. In hibernoma, the ANGPTL8 protein and mRNA were homogeneously expressed in tumor cells. The expression of ANGPTL8 was associated with the differentiation state and activity of lipid metabolism in a subpopulation of cells in the liver and adipose tissue. The association may be helpful for the understanding of local metabolic state in organs and diseases associated with the lipid metabolism.

Autologous transplantation of photoactivated subcutaneous adipose tissue improves glucose homeostasis in high-fat diet-induced obese mice.

Increasing evidence indicates that normal adipose tissue transplantation improves whole-body energy metabolism and glucose homeostasis in a high-fat diet (HFD)-induced obese mouse model. Adipose tissue macrophages are associated with glucose homeostasis and insulin resistance in type 2 diabetes and obesity in humans, offering a potential target for therapeutics. However, whether transplantation of autologous adipose tissue that changes the macrophage phenotype directly contributes to systemic glucose intolerance has not been determined. We specifically developed our device, with more refined wavelengths of light to activate the macrophage phenotype in isolated subcutaneous white adipose tissue (sWAT) from host HFD mice. Autologous transplantation of photoactivated sWAT into HFD mice significantly reverses the M1 macrophage phenotype into M2, reduces the infiltration of macrophages in adipose tissues of HFD mice, and decreases the levels of proinflammatory cytokines. Strikingly, this transplantation reduced blood glucose levels and caused significant improvement in glucose tolerance, which was not shown in sham-operated or nonphotoactivated sWAT-transplanted HFD mice. Moreover, positron emission/computed tomography scans indicated higher glucose uptake in the heart but not in the liver, hindlimb muscles, or abdominal sWAT. These data suggested that the ability of photoactivation to shift Adipose tissue macrophage polarization in HFD mice caused a significant improvement in glucose homeostasis and that autologous transplantation might be a promising therapeutic option for the treatment of diabetes.

Abstract 843: Epigenomic disruption of adipogenic regulators in dedifferentiated liposarcoma

Abstract Well-differentiated liposarcomas (WDLPS) and dedifferentiated liposarcomas (DDLPS) are the most common soft-tissue sarcomas in adults. They develop as a result of a disturbance in adipogenic differentiation however, the epigenomic changes underlying liposarcomagenesis are unknown. Here, we aimed to elucidate the role of epigenomic alterations in the initiation of DDLPS. Genome-wide DNA methylation profiles of 15 liposarcoma (6 WDLPS and 9 DDLPS) samples and 6 normal adipose tissue samples were obtained using the Infinium MethylationEPIC BeadChip. After grouping neighboring probes into genomic blocks (GBs, &amp;lt; 500 bp), principal component analysis of all the CpG GBs (n = 535,684) was conducted. Each of normal adipose tissue and WDLPS grouped closely while DDLPS distributed broadly, indicating heterogeneous methylation profiles among the DDLPS samples. Unsupervised hierarchical cluster analysis of enhancers (2,000 GBs with the high SD of 23,478 GBs) classified the samples into three tissue types, whereas that of promoters (1,000 GBs with the high SD of 8,668 GBs) could not classify the DDLPS samples distinctly. The Jonckheere-Terpstra trend test revealed 9,945 hypermethylated (p &amp;lt; 0.01, Δβ &amp;gt; 0.2) GBs in DDLPS compared to those in normal adipose tissues and WDLPS samples. Based upon a report on enhancers in adipocytes (Mikkelsen et al. Cell 143, 156-169. 2010), the hypermethylated GBs in DDLPS were enriched with typical- (2.2%: whole genome 1.2%) and super- (13.5%: whole genome 7.0%) enhancers. Genes involved in adipogenesis, including PPARG2, the master regulator of adipogenesis, and its target genes (FABP4 and PLIN1), were aberrantly methylated at the enhancers and repressed in DDLPS. Conversely, promoters were not enriched among hypermethylated GBs in DDLPS (1.2%: whole genome 4.1%). Taken together, these data indicate that aberrant methylation at the enhancers of adipogenic genes might be crucial for the generation of DDLPS. Evaluation of a demethylating agent in combination with a PPARγ agonist as a potential therapeutic is in progress. Citation Format: Hironori Takamatsu, Naoko Hattori, Naofumi Asano, Naoko Iida, Akihiko Yoshida, Eisuke Kobayashi, Robert Nakayama, Morio Matsumoto, Masaya Nakamura, Akira Kawai, Toshikazu Ushijima. Epigenomic disruption of adipogenic regulators in dedifferentiated liposarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 843.

Perilipin 1 Expression Differentiates Liposarcoma from Other Types of Soft Tissue Sarcoma

Lipid droplets, a morphologic feature of adipocytic tumors, are strongly regulated by associated proteins of the perilipin/PAT (perilipin, adipophilin, and tail-interacting protein of 47 kD) family. So far, the use of perilipins as markers for differential diagnosis of soft tissue tumors has only been studied in a few cases. The aim of this study was to investigate the expression of perilipins in 478 human soft tissue tumors and 60 respective normal tissues. Perilipin 1 was immunohistochemically positive in all studied cases of well-differentiated liposarcomas, >90% of myxoid round cell liposarcomas, and >70% of pleomorphic liposarcomas, whereas only the differentiated components of dedifferentiated liposarcomas were immunohistochemically positive for perilipin 1. All other types of soft tissue sarcomas were negative for perilipin 1. Perilipin 2 was more prominent in dedifferentiated and pleomorphic liposarcomas and nearly all other high-grade sarcomas. In well-differentiated liposarcomas, lipomas, or normal adipose tissue, perilipin 2 was virtually absent. In addition, long-term stimulation of adipogenesis in the liposarcoma cell line LiSa-2 restored perilipin 1 expression, as exhibited in the source tumor. Furthermore, knockdown of perilipin 2 or perilipin 3 in LiSa-2 cells influenced lipid droplet number and size as well as cell vitality. In summary, perilipin 1 is a promising marker for the differential diagnosis of liposarcomas from other soft tissue sarcomas, whereas perilipin 2 correlates negatively with tumor grade and may be therapeutically useful.

Mechanical Micronization of Lipoaspirates for Regenerative Therapy.

Stromal vascular fraction (SVF) has become a regenerative tool for various diseases; however, legislation strictly regulates the clinical application of cell products using collagenase. Here, we present a protocol to generate an injectable mixture of SVF cells and native extracellular matrix from adipose tissue by a purely mechanical process. Lipoaspirates are put into a centrifuge and spun at 1,200 x g for 3 min. The middle layer is collected and separated into two layers (high-density fat at the bottom and low-density fat on the top). The upper layer is directly emulsified by intersyringe shifting, at a rate of 20 mL/s for 6x to 8x. The emulsified fat is centrifuged at 2,000 x g for 3 min, and the sticky substance under the oil layer is collected and defined as the extracellular matrix (ECM)/SVF-gel. The oil on the top layer is collected. Approximately 5 mL of oil is added to 15 mL of high-density fat and emulsified by intersyringe shifting, at a rate of 20 mL/s for 6x to 8x. The emulsified fat is centrifuged at 2,000 x g for 3 min, and the sticky substance is also ECM/SVF-gel. After the transplantation of the ECM/SVF-gel into nude mice, the graft is harvested and assessed by histologic examination. The result shows that this product has the potential to regenerate into normal adipose tissue. This procedure is a simple, effective mechanical dissociation procedure to condense the SVF cells embedded in their natural supportive ECM for regenerative purposes.

Circ_0075932 in adipocyte-derived exosomes induces inflammation and apoptosis in human dermal keratinocytes by directly binding with PUM2 and promoting PUM2-mediated activation of AuroraA/NF-κB pathway

It remains unclear why obese persons displayed a slower wound healing rate than the normal. In this study, we found that has_circ_0075932, a single-exon circular RNA, was outstandingly expressed in human normal adipose tissue and overexpressed in burned skin of obese persons compared with that of non-obese persons. Circ_0075932 overexpression or silencing in dermal keratinocytes had no obvious effect on cell behaviors, unless dozens of times overexpression, since its basal expression level in keratinocytes is too low. However, the exosome released from circ_0075932-overexpressing adipocytes displayed a significantly promoting effect on inflammation and apoptosis in dermal keratinocytes. Then, in our mechanism exploration, we found that circ_0075932 directly bound with the RNA-binding protein PUM2, which was reported to positively regulated AuroraA kinase, thus activating the NF-κB pathway. Moreover, either silencing PUM2, silencing AuroraA, or blockade of NF-κB activation, could abrogate the promoting effect of adipocyte-derived exosomal circ_0075932 on cell inflammation and apoptosis.

Measurement of breast-tissue x-ray attenuation by spectral imaging: fresh and fixed normal and malignant tissue

Knowledge of x-ray attenuation is essential for developing and evaluating x-ray imaging technologies. In mammography, measurement of breast density, dose estimation, and differentiation between cysts and solid tumours are example applications requiring accurate data on tissue attenuation. Published attenuation data are, however, sparse and cover a relatively wide range. To supplement available data we have previously measured the attenuation of cyst fluid and solid lesions using photon-counting spectral mammography. The present study aims to measure the attenuation of normal adipose and glandular tissue, and to measure the effect of formalin fixation, a major uncertainty in published data. A total of 27 tumour specimens, seven fibro-glandular tissue specimens, and 15 adipose tissue specimens were included. Spectral (energy-resolved) images of the samples were acquired and the image signal was mapped to equivalent thicknesses of two known reference materials, from which x-ray attenuation as a function of energy can be derived. The spread in attenuation between samples was relatively large, partly because of natural variation. The variation of malignant and glandular tissue was similar, whereas that of adipose tissue was lower. Formalin fixation slightly altered the attenuation of malignant and glandular tissue, whereas the attenuation of adipose tissue was not significantly affected. The difference in attenuation between fresh tumour tissue and cyst fluid was smaller than has previously been measured for fixed tissue, but the difference was still significant and discrimination of these two tissue types is still possible. The difference between glandular and malignant tissue was close-to significant; it is reasonable to expect a significant difference with a larger set of samples. We believe that our studies have contributed to lower the overall uncertainty of breast tissue attenuation in the literature due to the relatively large sample sets, the novel measurement method, and by clarifying the difference between fresh and fixed tissue.

Adipose tissue transplantation ameliorates lipodystrophy-associated metabolic disorders in seipin-deficient mice.

Seipin deficiency is responsible for type 2 congenital generalized lipodystrophy with severe loss of adipose tissue and can lead to hepatic steatosis, insulin resistance (IR), and dyslipidemia in humans. Adipose tissue secretes many adipokines that are central to the regulation of metabolism. In this study, we investigated whether transplantation of normal adipose tissue could ameliorate severe hepatic steatosis, IR, and dyslipidemia in lipoatrophic seipin knockout (SKO) mice. Normal adipose tissue from wild-type mice was transplanted into 6-wk-old SKO mice. At 4 mo after adipose tissue transplantation (AT), the transplanted fat survived with detectable blood vessels, and the reduced levels of plasma leptin, a major adipokine, were dramatically increased. Severe hepatic steatosis, IR, and dyslipidemia in SKO mice were ameliorated after AT. In addition, abnormal hepatic lipogenesis and β-oxidation gene expression in SKO mice were improved after AT. Our results suggest that AT may be an effective treatment to improve lipodystrophy-associated metabolic disorders.