Simultaneous Application of High-Intensity Focused Electromagnetic and Synchronized Radiofrequency for Fat Disruption: Histological and Electron Microscopy Porcine Model Study.

BACKGROUND: Radiofrequency (RF) and high-intensity focused electromagnetic (HIFEM) technologies are used for noninvasive body shaping as standalone modalities. OBJECTIVE: To examine the effects of novel synchronized RF and HIFEM on subcutaneous adipose tissue in a porcine animal model. MATERIALS AND METHODS: Seven large white pigs aged 6 months received 3 abdominal treatments of simultaneous application of synchronized RF and HIFEM (30 minutes, once per week). Punch biopsies of treated and control subcutaneous tissue were collected at the baseline, 4 days, 2 weeks, 1 month, and 2 months. Specimens were examined by light and scanning electron microscopy. Adipocyte volume was analyzed. Fat tissue temperature was measured in situ (fiber optic probes) and superficially (thermal imager). RESULTS: Fat layer was heated to temperatures of 42 to 45°C. Signs of fat apoptosis (shape alternations and pyknotic nuclei) appeared at day 4 and peaked between 2 weeks and 1 month. Adipocyte volume decreased significantly (p < .001) by 31.1% at 2 weeks, 1 month (-23.6%), and 2 months (-22.0%). Control samples showed healthy adipocytes. Scanning electron microscopy micrographs corroborated histology findings, showing flattened, volume-depleted and disrupted adipocytes. CONCLUSION: Synchronized RF with HIFEM procedure resulted in a significant and sustained fat reduction with no adverse events.

Elaidate, a trans fatty acid, suppresses insulin signaling for glucose uptake in a manner distinct from that of stearate.

The dietary intake of elaidate (elaidic acid), a trans-fatty acid, is associated with the development of various diseases. Since elaidate is a C18 unsaturated fatty acid with a steric structure similar to that of a C18 saturated fatty acid (stearate), we previously revealed that insulin-dependent glucose uptake was impaired in adipocytes exposed to elaidate prior to and during differentiation similar to stearate. However, it is still unknown whether the mechanism of impairment of insulin-dependent glucose uptake due to elaidate is similar to that of stearate. Here, we indicate that persistent exposure to elaidate has particular effects on insulin signaling and GLUT4 dynamics. Insulin-induced accumulation of Akt at the plasma membrane (PM) and elevations of phosphorylated Akt and AS160 levels in whole cells were suppressed in adipocytes persistently exposed to 50 µM elaidate. Interestingly, persistent exposure to the same concentration of stearate has no effect on the phosphorylated Akt and AS160 levels. When cells were exposed to these fatty acids, elaidate suppressed insulin-induced fusion, but not translocation, of GLUT4 storage vesicles in the PM, whereas stearate did not suppress the fusion and translocation of GLUT4 storage, indicating that elaidate has suppressive effects on the accumulation of Akt and fusion of GLUT4 storage vesicles and that both elaidate and stearate vary in the mechanisms by which they impair insulin-dependent glucose uptake.

In-Vitro-Generated Hypertrophic-Like Adipocytes Displaying PPARG Isoforms Unbalance Recapitulate Adipocyte Dysfunctions In Vivo.

Reduced neo-adipogenesis and dysfunctional lipid-overloaded adipocytes are hallmarks of hypertrophic obesity linked to insulin resistance. Identifying molecular features of hypertrophic adipocytes requires appropriate in vitro models. We describe the generation of a model of human hypertrophic-like adipocytes directly comparable to normal adipose cells and the pathologic evolution toward hypertrophic state. We generate in vitro hypertrophic cells from mature adipocytes, differentiated from human mesenchymal stem cells. Combining optical, confocal, and transmission electron microscopy with mRNA/protein quantification, we characterize this cellular model, confirming specific alterations also in subcutaneous adipose tissue. Specifically, we report the generation and morphological/molecular characterization of human normal and hypertrophic-like adipocytes. The latter displays altered morphology and unbalance between canonical and dominant negative (PPARGΔ5) transcripts of PPARG, paralleled by reduced expression of PPARγ targets, including GLUT4. Furthermore, the unbalance of PPARγ isoforms associates with GLUT4 down-regulation in subcutaneous adipose tissue of individuals with overweight/obesity or impaired glucose tolerance/type 2 diabetes, but not with normal weight or glucose tolerance. In conclusion, the hypertrophic-like cells described herein are an innovative tool for studying molecular dysfunctions in hypertrophic obesity and the unbalance between PPARγ isoforms associates with down-regulation of GLUT4 and other PPARγ targets, representing a new hallmark of hypertrophic adipocytes.

Adipocyte-specific Beclin1 deletion impairs lipolysis and mitochondrial integrity in adipose tissue.

OBJECTIVE: Beclin1 is a core molecule of the macroautophagy machinery. Although dysregulation of macroautophagy is known to be involved in metabolic disorders, the function of Beclin1 in adipocyte metabolism has not been investigated. In the present study, we aimed to study the role of Beclin1 in lipolysis and mitochondrial homeostasis of adipocytes. METHODS: Autophagic flux during lipolysis was examined in adipocytes cultured in vitro and in the adipose tissue of mice. Adipocyte-specific Beclin1 knockout (KO) mice were used to investigate the activities of Beclin1 in adipose tissues. RESULTS: cAMP/PKA signaling increased the autophagic flux in adipocytes differentiated from C3H10T1/2 cells. In vivo autophagic flux was higher in the brown adipose tissue (BAT) than that in the white adipose tissue and was further increased by the ß3 adrenergic receptor agonist CL316243. In addition, surgical denervation of BAT greatly reduced autophagic flux, indicating that sympathetic nerve activity is a major regulator of tissue autophagy. Adipocyte-specific KO of Beclin1 led to a hypertrophic enlargement of lipid droplets in BAT and impaired CL316243-induced lipolysis/lipid mobilization and energy expenditure. While short-term effects of Beclin1 deletion were characterized by an increase in mitochondrial proteins, long-term Beclin1 deletion led to severe disruption of autophagy, resulting in mitochondrial loss, and dramatically reduced the expression of genes involved in lipid metabolism. Consequently, adipose tissue underwent increased activation of cell death signaling pathways, macrophage recruitment, and inflammation, particularly in BAT. CONCLUSIONS: The present study demonstrates the critical roles of Beclin1 in the maintenance of lipid metabolism and mitochondrial homeostasis in adipose tissues.

Influence of software parameters on measurements in automatized image-based analysis of fat tissue histology.

The understanding of fat tissue plays an eminent role in plastic surgery as well as in metabolic research. Histopathological analysis of tissue samples provides insight in free fat graft survival and culture experiments help to better understand fat tissue derived stem cells (ASCs). To facilitate such experiments, modern image-based histology could provide an automatized approach to a large amount of data to gain not only qualitative but also quantitative data. This study was designed to critically evaluate image-based analysis of fat tissue samples in cell culture or in tissue probes and to identify critical parameters to avoid bias in further studies. In the first part of the study, ASCs were harvested and differentiated into adipocytes in cell culture. Histology was performed with the fluorescent dye BODIPY and the obtained digital images were analyzed using Image J software. In the second part of the study, digitalized histology of a previous in vivo study was subjected to automatized fat vacuole quantification using Image J. Both approaches were critically reviewed, and different software parameter settings were tested. Results showed that automatized digital image analysis allows the quantification of fat tissue probes with enough precision giving significant results. But the testing of different software parameters revealed a significant influence of parameters themselves on calculated results. Therefore, we recommend the use of image-based analysis to quantify fat tissue probes to improve the comparability of studies. But we also emphasize to calibrate software using internal controls in every single experimental approach.

Human Bone Marrow Is Comprised of Adipocytes with Specific Lipid Metabolism.

Under caloric restriction, bone marrow adipocytes (BM-Ads) do not decrease in size compared to white adipocytes, suggesting they harbor unique metabolic properties. We compare human primary BM-Ads with paired subcutaneous adipocytes (SC-Ads) using proteomic and lipidomic approaches. We find that, although SC-Ads and BM-Ads share similar morphological features, they possess distinct lipid metabolism. Although BM-Ad shows enrichment in proteins involved in cholesterol metabolism, correlating with increased free cholesterol content, proteins involved in lipolysis were downregulated. In particular, monoacylglycerol lipase expression is strongly reduced in BM-Ads, leading to monoacylglycerol accumulation. Consequently, basal and induced lipolytic responses are absent in BM-Ads, affirming their differences in metabolic fitness upon caloric restriction. These specific metabolic features are not recapitulated in vitro using common protocols to differentiate bone marrow mesenchymal stem cells. Thus, contrary to classical SC-Ads, BM-Ads display a specific lipid metabolism, as they are devoid of lipolytic activity and exhibit a cholesterol-orientated metabolism.

m6A mRNA methylation controls autophagy and adipogenesis by targeting Atg5 and Atg7.

N: 6-methyladenosine (m6A), the most abundant internal modification on mRNAs in eukaryotes, play roles in adipogenesis. However, the underlying mechanism remains largely unclear. Here, we show that m6A plays a critical role in regulating macroautophagy/autophagy and adipogenesis through targeting Atg5 and Atg7. Mechanistically, knockdown of FTO, a well-known m6A demethylase, decreased the expression of ATG5 and ATG7, leading to attenuation of autophagosome formation, thereby inhibiting autophagy and adipogenesis. We proved that FTO directly targeted Atg5 and Atg7 transcripts and mediated their expression in an m6A-dependent manner. Further study identified that Atg5 and Atg7 were the targets of YTHDF2 (YTH N6-methyladenosine RNA binding protein 2). Upon FTO silencing, Atg5 and Atg7 transcripts with higher m6A levels were captured by YTHDF2, which resulted in mRNA degradation and reduction of protein expression, thus alleviating autophagy and adipogenesis. Furthermore, we generated an adipose-selective fto knockout mouse and find that FTO deficiency decreased white fat mass and impairs ATG5- and ATG7-dependent autophagy in vivo. Together, these findings unveil the functional importance of the m6A methylation machinery in autophagy and adipogenesis regulation, which expands our understanding of such interplay that is essential for development of therapeutic strategies in the prevention and treatment of obesity. ABBREVIATIONS: 3-MA: 3-methyladenine; ACTB: actin, beta; ATG: autophagy-related; Baf A1: bafilomycin A1; CEBPA: CCAAT/enhancer binding protein (C/EBP), alpha; CEBPB: CCAAT/enhancer binding protein (C/EBP), beta; FABP4: fatty acid binding protein 4, adipocyte; FTO: fat mass and obesity associated; HFD: high-fat diet; LC-MS/MS: liquid chromatography-tandem mass spectrometry; MAP1LC3B/LC3: microtubule-associated protein 1 light chain 3 beta; m6A: N6-methyladenosine; MEFs: mouse embryo fibroblasts; MeRIP-qPCR: methylated RNA immunoprecipitation-qPCR; PPARG: peroxisome proliferator activated receptor gamma; RIP: RNA-immunoprecipitation; SAT: subcutaneous adipose tissue; siRNA: small interfering RNA; SQSTM1/p62: sequestosome 1; TEM: transmission electron microscopy; ULK1: unc-51 like kinase 1; VAT: visceral adipose tissue; WAT: white adipose tissue; YTHDF: YTH N6-methyladenosine RNA binding protein.

Correlation between Nuclear Morphology and Adipogenic Differentiation: Application of a Combined Experimental and Computational Modeling Approach.

Stem cells undergo drastic morphological alterations during differentiation. While extensive studies have been performed to examine the cytoskeletal remodeling, there is a growing interest to determine the morphological, structural and functional changes of the nucleus. The current study is therefore aimed at quantifying the extent of remodeling of the nuclear morphology of human mesenchymal stem cells during biochemically-induced adipogenic differentiation. Results show the size of nuclei decreased exponentially over time as the lipid accumulation is up-regulated. Increases in the lipid accumulation appear to lag the nuclear reorganization, suggesting the nuclear deformation is a prerequisite to adipocyte maturation. Furthermore, the lamin A/C expression was increased and redistributed to the nuclear periphery along with a subsequent increase in the nuclear aspect ratio. To further assess the role of the nucleus, a nuclear morphology with a high aspect ratio was achieved using microcontact-printed substrate. The cells with an elongated nuclear shape did not efficiently undergo adipogenesis, suggesting the cellular and nuclear processes associated with stem cell differentiation at the early stage of adipogenesis cause a change in the nuclear morphology and cannot be abrogated by the morphological cues. In addition, a novel computational biomechanical model was generated to simulate the nuclear shape change during differentiation and predict the forces acting upon the nucleus. This effort led to the development of computational scaling approach to simulate the experimentally observed adipogenic differentiation processes over 15 days in less than 1.5 hours.

Sec20 is Required for Autophagic and Endocytic Degradation Independent of Golgi-ER Retrograde Transport.

Endocytosis and autophagy are evolutionarily conserved degradative processes in all eukaryotes. Both pathways converge to the lysosome where cargo is degraded. Improper lysosomal degradation is observed in many human pathologies, so its regulatory mechanisms are important to understand. Sec20/BNIP1 (BCL2/adenovirus E1B 19 kDa protein-interacting protein 1) is a BH3 (Bcl-2 homology 3) domain-containing SNARE (soluble N-ethylmaleimide-sensitive factor-attachment protein receptors) protein that has been suggested to promote Golgi-ER retrograde transport, mitochondrial fission, apoptosis and mitophagy in yeast and vertebrates. Here, we show that loss of Sec20 in Drosophila fat cells causes the accumulation of autophagic vesicles and prevents proper lysosomal acidification and degradation during bulk, starvation-induced autophagy. Furthermore, Sec20 knockdown leads to the enlargement of late endosomes and accumulation of defective endolysosomes in larval Drosophila nephrocytes. Importantly, the loss of Syx18 (Syntaxin 18), one of the known partners of Sec20, led to similar changes in nephrocytes and fat cells. Interestingly. Sec20 appears to function independent of its role in Golgi-ER retrograde transport in regulating lysosomal degradation, as the loss of its other partner SNAREs Use1 (Unconventional SNARE In The ER 1) and Sec22 or tethering factor Zw10 (Zeste white 10), which function together in the Golgi-ER pathway, does not cause defects in autophagy or endocytosis. Thus, our data identify a potential new transport route specific to lysosome biogenesis and function.

Caveolins; An Assailant or An Ally of Various Cellular Disorders.

Caveolae have impressive morphological highlights of the cytomembrane of mammalian cells which involve in wide diversity of cellular functions involving signaling pathways and cholesterol hastening. Caveolin proteins possess a 'scaffolding' domain which for caveolin-1 and caveolin-3 appear to act a dominant role in signal regulation through caveolae. Caveolin-1 is treated to be protein in the cytomembrane entrapped with caveolae in endothelial cells and vascular smooth muscle cells which diminish nitric oxide (NO) by fill up the calcium/calmodulin (Ca2+/CaM) confining point of endothelial nitric oxide synthase (eNOS), decrease NO generation produce endothelial dysfunction and atherosclerotic injury development. It is a cholesterol-binding layer protein associated with cell cholesterol transport and also shows cardioprotective action through ischemic preconditioning (IPC) in diabetic and postmenopausal rat heart. Additionally it is ensnared in the procedures of tumorigenesis, prostate disease, and inflammation. The present study in the paper is to explore the structural functionalities of caveolins and their contributory role in CVS disorders and various other diseases.

Characterization of the bone marrow adipocyte niche with three-dimensional electron microscopy.

Unlike white and brown adipose tissues, the bone marrow adipocyte (BMA) exists in a microenvironment containing unique populations of hematopoietic and skeletal cells. To study this microenvironment at the sub-cellular level, we performed a three-dimensional analysis of the ultrastructure of the BMA niche with focused ion beam scanning electron microscopy (FIB-SEM). This revealed that BMAs display hallmarks of metabolically active cells including polarized lipid deposits, a dense mitochondrial network, and areas of endoplasmic reticulum. The distinct orientations of the triacylglycerol droplets suggest that fatty acids are taken up and/or released in three key areas - at the endothelial interface, into the hematopoietic milieu, and at the bone surface. Near the sinusoidal vasculature, endothelial cells send finger-like projections into the surface of the BMA which terminate near regions of lipid within the BMA cytoplasm. In some regions, perivascular cells encase the BMA with their flattened cellular projections, limiting contacts with other cells in the niche. In the hematopoietic milieu, BMAT adipocytes of the proximal tibia interact extensively with maturing cells of the myeloid/granulocyte lineage. Associations with erythroblast islands are also prominent. At the bone surface, the BMA extends organelle and lipid-rich cytoplasmic regions toward areas of active osteoblasts. This suggests that the BMA may serve to partition nutrient utilization between diverse cellular compartments, serving as an energy-rich hub of the stromal-reticular network. Lastly, though immuno-EM, we've identified a subset of bone marrow adipocytes that are innervated by the sympathetic nervous system, providing an additional mechanism for regulation of the BMA. In summary, this work reveals that the bone marrow adipocyte is a dynamic cell with substantial capacity for interactions with the diverse components of its surrounding microenvironment. These local interactions likely contribute to its unique regulation relative to peripheral adipose tissues.

Comparative Effect between Sardine Oil and Fish Oil Rich in Omega-3 Fatty Acids on Hypertension and the Membrane Composition of Adipocytes in SHR Rats.

Omega-3 polyunsaturated fatty acids, have an important role in reducing hypertriglyceridemia, these acids decrease the mortality for Coronary Heart Disease. Very important is the relationship between fatty acid biosynthesis and distribution in organs and tissues involved in insulin resistance and hypertension due to its role in the production of vasoactive eicosanoids and their effects on insulin sensitivity; which is estimated with the HOMA-IR index, which relates the physiological and metabolic behavior of glucose and insulin in the body. The aim of this project was to compare the effect of sardine oil and omega-3 oils rich in polyunsaturated fatty acids: EPA (≈30%) and DHA (≈50%) administered for 6 to 8 wk respectively; on the lipid composition of the plasma membrane of epididymal adipocytes in spontaneously hypertensive rats (SHR) and their relation to obesity, insulin resistance and hypertension. The administration of omega-3 enriched oil significantly decreased the HOMA criteria as an insulin resistance indicator compared to the sardine oil.

Cutaneous intramuscular lipoma: A new subtype of intramuscular lipoma.

Intramuscular lipoma is an uncommon variant of lipoma that occurs inside muscle tissue. Pathogenesis is thought to be related to neoplastic activity of mesenchymal stem cells, but there still is not an established theory. This entity can be found in almost all areas of the body, mostly within or in connection with skeletal muscle tissue. We have encountered an atypical intramuscular lipoma located in the epidermal layer of the right thigh of an otherwise healthy 35-year-old female. The superficial, protruding skin mass resembled a sebaceous nevus or skin malignancy but was histologically composed of well-defined adipocytes between a mixture of muscle fibers, corresponding with the diagnosis of intramuscular lipoma. Intramuscular lipoma of the skin has never been reported before; thus, the authors suggest the classification "cutaneous" intramuscular lipoma to describe lesions located in the dermal or epidermal layer.

Ultrastructural analysis of human umbilical cord derived MSCs at undifferentiated stage and during osteogenic and adipogenic differentiation.

Mesenchymal stem cells (MSCs) are considered as an important tool for regenerative medicine and experimental treatments. Unveiling the ultrastructural changes during the differentiation of MSCs might help us to understand the nature of the process and to develop novel therapeutic approaches. For this purpose, human umbilical cord (hUC) was chosen as MSC source. In the first place, MSCs were isolated from sub-amniotic, intervascular and perivascular areas of hUC by enzymatic and tissue explant method to determine the most favorable region of hUC and technique for further processing. Therefore, microscopic and growth kinetics analyses showed that there was no clear difference in the morphologies and proliferation rates among the hUC-MSC groups. Flow cytometric analysis showed that CD44 and CD90 MSC markers were highly expressed, while CD34 and CD45 hematopoietic stem cells markers were expressed at low degree. Because our preliminary results showed that there was no conspicuous superiority among the hUC-MSCs groups, whole UC was utilized as a source, and tissue explant method was applied to isolate MSCs for further differentiation analysis. At the 1st and 3rd week of osteogenic and adipogenic differentiation, ultrastructural analysis showed an increase in the number of secondary lysosomes in comparison with the undifferentiated status. Increase in the mitochondrial content was also detected at the 1st week of adipogenic differentiation. Consequently, ultrastructural changes including increase in the number of mitochondria and secondary lysosomes during the adipogenic and osteogenic differentiation could be attributed to the switch in energy metabolism of the MSCs and increment in the lysosomal activity respectively.

Liponeurofibroma: Clinicopathological features and histogenesis.

A neurofibroma is a common cutaneous benign tumor of neural origin. Various histological variants have been reported. Recently, sporadic reports of fatty variants have been reported but their clinicopathological features have not been well studied. The purpose of this study was to examine liponeurofibroma, and to report the distinctive clinicopathological features and histogenesis in comparison with the classic form. A retrospective study was performed on 130 cases. Immunohistochemical staining was performed for S100, factor VIIIa, perilipin and vascular endothelial growth factor. Masson's trichrome stain was also used. Intratumoral adipocytes were examined with transmission electron microscopy. Thirty-two (24.6%) cases were classified as liponeurofibroma on microscopic examination. This variant was more common in patients with neurofibromatosis type 1, older age and female sex. The most prevalent location was the head and neck. Intratumoral fat deposits showed differences in morphology and size compared with subcutaneous fat on light microscopy. Neurofibromatosis type 1 had the highest odds of fatty change in liponeurofibroma. In sporadic cases, fatty change can be caused by senescence, chronic injury, or tissue hypoxia secondary to internal or external stimuli. Further investigation is needed to identify the pathomechanism of fatty change in various cutaneous neoplasms, including neurofibroma.

Perinatal nicotine exposure increases obesity susceptibility by peripheral leptin resistance in adult female rat offspring.

Maternal nicotine (NIC) exposure causes overweight, hyperleptinemia and metabolic disorders in adult offspring. Our study aims to explore the underlying mechanism of perinatal NIC exposure increases obesity susceptibility in adult female rat offspring. In our model, we found that adult NIC-exposed females presented higher body weight and subcutaneous and visceral fat mass, as well as larger adipocytes, while no change was found in food intake. Serum profile showed a higher serum glucose, insulin and leptin levels in NIC-exposed females. In adipose tissue and liver, the leptin signaling pathway was blocked at 26 weeks, presented lower Janus tyrosine kinase 2 and signal transducer and activator of transcription 3 gene expression, higher suppressor of cytokine signaling 3 gene expression (in adipose tissue) and lower leptin receptors gene expression (in liver), indicating that peripheral leptin resistance occurred in NIC-exposed adult females. In female rats, the expression of lipolysis genes was affected dominantly in adipose tissue, but lipogenesis genes was affected in liver. Furthermore, the glucose and insulin tolerance tests showed a delayed glucose clearance and a higher area under the curve in NIC-exposed females. Therefore, perinatal NIC exposure programed female rats for adipocyte hypertrophy and obesity in adult life, through the leptin resistance in peripheral tissue.

Circulating Soluble IL-6 Receptor Concentration and Visceral Adipocyte Size Are Related to Insulin Resistance in Taiwanese Adults with Morbid Obesity.

BACKGROUND: Morbid obesity is related to chronic inflammation and many metabolic complications. Interleukin (IL)-6 plays a pivotal pathophysiological role in obesity, and IL-6 trans-signaling through the soluble IL-6 receptor (sIL-6R) has a major proinflammatory effect. The aim of this study was to investigate the association between sIL-6R, adipocyte size, and insulin resistance in morbidly obese individuals. METHODS: We measured concentrations of sIL-6R, high-sensitivity C-reactive protein, and lipid parameters and estimated homeostasis model assessment of insulin resistance (HOMA-IR) before the patients underwent bariatric surgery. Mesenteric adipose tissue was collected during surgery, and adipocyte size and concentrations of membrane-bound IL-6 receptor (mIL-6R) were evaluated. In total, 35 adults (20 men and 15 women) were recruited. RESULTS: The subjects with high HOMA-IR (≥2.4) had higher fasting glucose/insulin, triglycerides, sIL-6R, and adipocyte size and lower high-density lipoprotein cholesterol and mIL-6R than those with low HOMA-IR (<2.4). Adipocyte size positively correlated with sIL-6R (r = 0.559, P = 0.001) and HOMA-IR (r = 0.773, P ≤ 0.001) independent of age, gender, body mass index (BMI), waist, and use of diabetic drugs. In addition, every 1 ng/mL increase in sIL-6R concentration corresponded to a 10.2% decrease in the likelihood of maintaining lower insulin resistance. Furthermore, an sIL-6R level of 77.45 ng/mL was a reasonable cutoff level to propose lower insulin resistance in morbidly obese subjects. CONCLUSIONS: Circulating sIL-6R is more closely associated with insulin resistance status than waist-to-hip ratio or BMI in morbidly obese Taiwanese adults. sIL-6R may be a useful biomarker to assess insulin resistance among morbidly obese subjects.

Diabetes-Specific Regulation of Adipocyte Metabolism by the Adipose Tissue Extracellular Matrix.

Context: The role of the extracellular matrix (ECM) in regulating adipocyte metabolism in the context of metabolic disease is poorly defined. Objective: The objective of this study was to define the metabolic phenotype of adipocytes associated with human diabetes (DM) and the role of the ECM in regulating adipocyte metabolism. Design: Adipose tissues from obese patients were studied in standard 2-dimensional (2D) cell culture and an in vitro model of decellularized adipose tissue ECM repopulated with human adipocytes, and results were correlated with DM status. Setting: This study was conducted at the Academic University Medical Center and Veteran's Administration Hospital. Patients: Seventy patients with morbid obesity undergoing bariatric surgery were included in the study. Interventions: Visceral and subcutaneous adipose tissues were collected at the time of bariatric surgery. Outcome measures: This study used metabolic assays for glucose uptake, lipolysis, and lipogenesis in adipocytes in 2D cell culture and 3-dimensional ECM culture. Results: Adipocytes from subjects with DM manifest decreased glucose uptake and decreased lipolysis in 2D culture. ECM supports differentiation of mature adipocytes and recapitulates DM-specific differences in adipocyte metabolism observed in 2D culture. ECM from subjects without DM partially rescues glucose uptake and lipolytic defects in adipocytes from subjects with DM, whereas ECM from subjects with DM impairs glucose uptake in adipocytes from subjects without DM. Conclusions: DM is associated with adipocyte metabolic dysfunction. The ECM regulates adipocyte metabolism. Nondiabetic ECM rescues metabolic dysfunction in DM adipocytes, whereas DM ECM imparts features of metabolic dysfunction to nondiabetic adipocytes. These findings suggest the ECM as a target for manipulating adipose tissue metabolism.

Development, fabrication and evaluation of a novel biomimetic human breast tissue derived breast implant surface.

Breast implant use has tripled in the last decade with over 320,000 breast implant based reconstructions and augmentations performed in the US per annum. Unfortunately a considerable number of women will experience capsular contracture, the irrepressible and disfiguring, tightening and hardening of the fibrous capsule that envelops the implant. Functionalising implant surfaces with biocompatible tissue-specific textures may improve in vivo performance. A novel biomimetic breast implant is presented here with anti-inflammatory in vitro abilities. Topographical assessment of native breast tissue facilitated the development of a statistical model of adipose tissue. 3D grayscale photolithography and ion etching were combined to successfully replicate a surface modelled upon the statistics of breast tissue. Pro-inflammatory genes ILß1, TNFα, and IL6 were downregulated (p<0.001) and anti-inflammatory gene IL-10 were upregulated on the novel surface. Pro-inflammatory cytokines Gro-Alpha, TNFα and neutrophil chemoattractant IL8 were produced in lower quantities and anti-inflammatory IL-10 in higher quantities in culture with the novel surface (p<0.01). Immunocytochemistry and SEM demonstrated favourable fibroblast and macrophage responses to these novel surfaces. This study describes the first biomimetic breast tissue derived breast implant surface. Our findings attest to its potential translational ability to reduce the inflammatory phase of the implant driven foreign body reaction. STATEMENT OF SIGNIFICANCE: Breast implants are still manufactured using outdated techniques and have changed little since their inception in the 1960's. Breast implants can cause a medical condition, capsular contracture which often results in disfigurement, pain, implant removal and further surgery. This condition is due to the body's reaction to these breast implants. This article describes the successful development and testing of a novel breast implant surface inspired by the native shapes present in breast tissue. Results show that this novel implant surface is capable of reducing the negative reaction of human cells to these surfaces which may help reduce capsular contracture formation. This work represents the first steps in producing a biocompatible breast implant.

Adipocyte-derived microvesicles from obese mice induce M1 macrophage phenotype through secreted miR-155.

The pro-inflammatory profile of M1 macrophage accumulation in adipose tissue is a central event leading to the metabolic complications of obesity. However, the mechanisms by which M1 macrophages are enriched in adipose tissue during weight gain remain incompletely understood. Here, we investigated the effects of adipocyte-derived microvesicles (ADM) on modulating macrophage phenotype in mice and explored the involved molecular signalling pathways. We found that, compared with ADM from lean mice (SD ADM), ADM from obese mice (HFD ADM) significantly enhanced M1 marker expression. The quantitative RT-PCR assay demonstrated that miR-155 was upregulated in both HFD ADM and HFD ADM-treated macrophages. By depleting miR-155 expression in HFD ADM and increasing miR-155 level in SD ADM, we further illustrated that miR-155 in ADM-induced M1 macrophage polarization. Functionally, in contrast to SD ADM, HFD ADM significantly decreased the protein level of SOCS1, a proven miR-155 target, leading to activation of STAT1, and suppression of STAT6 signalling; these effects were reversed by silencing miR-155 in HFD ADM. Furthermore, the supernatant of bone marrow-derived macrophages pre-stimulated with miR-155-bearing ADM interfered with insulin signalling and insulin-induced glucose uptake in adipocytes. Collectively, these results provide the first evidence that M1 macrophage polarization can be mediated by miR-155-bearing ADM, which reciprocally regulates insulin signalling and glucose uptake in adipocytes. Our study reveals a novel mechanism through which obesity induces an imbalance in the M1-to-M2 macrophage ratio in adipose tissue, thus causing chronic inflammation and local insulin resistance.