Normal Adipose Tissue Research Articles

Features of multi-slice spiral computed tomography examination of mesenteric panniculitis

Objective To summarize the features of multi-slice spiral computed tomography(MSCT) examination of mesenteric panniculitis (MP). Methods The retrospective cross-sectional study was conducted. The clinical data of 105 patients with MP who were admitted to the Yangzhou NO. 1 People′s Hospital between September 2009 and September 2015 were collected. All the patients were diagnosed by MSCT and multiplanar reconstruction (MPR). Observation indicators: (1) imaging features of computed tomography (CT): location, number, shape, size, density, mesenteric vessels and surrounding intestine of the lesions, with or without pseudotumor sign, enlarged fibrous nodules or lymph nodes, pseudocapsule sign, fatring sign, cystolization and calcification; (2) follow-up results. Follow-up using outpatient examination was performed by plain and/or enhanced scans of abdominal CT up to April 2017. Results (1) Imaging features of CT: of 105 patients, 77, 14 and 14 received respectively plain scans of abdominal CT, plain and enhanced scans of abdominal CT and enhanced scans of abdominal CT. Lesions of 105 patients were located at the mesentery. The single lesion was detected in 79 patients and multiple lesions in 26 patients, with number of lesions of 5-12 per case and total number of 213. All the 105 patients had pseudotumor sign, which showed different size of patchy or mass shadows with clear edge extended from mesentery root to mesenteric vessels; most long axes extended from mesentery root to jejunum in the left lumbar region; the homogeneous or heterogeneous mesenteric fat density was increased, and CT value was higher than that of normal retroperitoneal adipose tissues; fog-like mesentery showed less obvious enhancement by enhanced scan and mesenteric vessels were wrapped around. The cord-like, round or oval fibrous tissue nodules and/or enlarged lymph nodes were found in 100 patients. All the 105 patients had pseudocapsule sign. The density ring of soft tissues of different thickness was found, with a clear boundary between leading- and trail-edges and normal abdominal and retroperitoneal adipose tissues; most membranes extended to left lumbar region, thicker and thinner membranes were respectively located at the anterior and posterior areas and right side, and parts of membranes were absence. The fatring sign was detected in 71 patients, there were ring-like hypodense shadows around the mesenteric vessels and fibrous tissue nodules or lymph nodes. Cystolization and calcification were found in 2 and 2 patients. Thirty-eight patients had surrounding intestinal canal translocation. (2) Follow-up results: 55 patients were followed up for 1.0-57.0 months, with an average time of 14.7 months. Of 55 patients, 26 had stable lesions and no obvious changes; 4 returned to normal due to complete absorption of lesions; 19 were improved due to partial absorption of lesions; 6 had lesions progressions. Conclusion The features of MSCT examination of MP include pseudotumor sign, pseudocapsule sign and fatring sign. Key words: Panniculitis; Mesentery; Multiplanar reconstruction; Tomography, X-ray computed

Spatial Statistics for Segmenting Histological Structures in H&E Stained Tissue Images.

Segmenting a broad class of histological structures in transmitted light and/or fluorescence-based images is a prerequisite for determining the pathological basis of cancer, elucidating spatial interactions between histological structures in tumor microenvironments (e.g., tumor infiltrating lymphocytes), facilitating precision medicine studies with deep molecular profiling, and providing an exploratory tool for pathologists. This paper focuses on segmenting histological structures in hematoxylin- and eosin-stained images of breast tissues, e.g., invasive carcinoma, carcinoma in situ, atypical and normal ducts, adipose tissue, and lymphocytes. We propose two graph-theoretic segmentation methods based on local spatial color and nuclei neighborhood statistics. For benchmarking, we curated a data set of 232 high-power field breast tissue images together with expertly annotated ground truth. To accurately model the preference for histological structures (ducts, vessels, tumor nets, adipose, etc.) over the remaining connective tissue and non-tissue areas in ground truth annotations, we propose a new region-based score for evaluating segmentation algorithms. We demonstrate the improvement of our proposed methods over the state-of-the-art algorithms in both region- and boundary-based performance measures.

Preparation and evaluation of extracellular matrix scaffold of human adipose tissue

25 g normal adipose tissue was cut into pieces. Then repeated freeze-thaw,enzymatic digestion,organic solvent extraction and vacuum freeze-drying were performed.Adult adipose tissue extracellular tissue matrix was obtained. The traits of extracellular matrix scaffold were observed.HE staining, Masson staining and DAPI fluorescence staining were used to test the effectiveness of the decellularization.Immunohistochemistry was used to detect the reservations of extracellular matrix (Ⅳ collagen, laminin).Scanning electron microscopy was introduced to observe the ultrastructure of extracellular matrix scaffold, and universal mechanical testing machine was used to measure the mechanical properties of the scaffolds. Enzyme digestion method was used to extract human adipose-derived stem cells (hADSCs),and then the 3rd passage hADSCs were cocultured with extracellular matrix scaffold.CCK8 was introduced to assay cell proliferation activity,and scanning electron microscopy was used to observe cellular adhesion. The cells on the scaffold were induced to adipocytes and observed by freezing section and Oil Red O staining after 14 days. The extracellular matrix scaffold of adipose tissue was porous sponges architecture. The cells in tissue were relatively removed. The collagen and laminin were preserved relatively, and the mechanical properties did not decline too much. The cell proliferation, adhesion and differentiation on the scaffold was very well. The extracellular matrix scaffold of adipose tissue, prepared through the methods of physical, chemical, enzymatic digestion and vacuum freeze-drying method, keeps the main ingredients of extracellular matrix and presents a well cellular compatibility, therefore it should be an ideal biologic scaffold for adipose tissue engineering.

Detection of Metastatic Breast and Thyroid Cancer in Lymph Nodes by Desorption Electrospray Ionization Mass Spectrometry Imaging.

Ambient ionization mass spectrometry has been widely applied to image lipids and metabolites in primary cancer tissues with the purpose of detecting and understanding metabolic changes associated with cancer development and progression. Here, we report the use of desorption electrospray ionization mass spectrometry (DESI-MS) to image metastatic breast and thyroid cancer in human lymph node tissues. Our results show clear alterations in lipid and metabolite distributions detected in the mass spectra profiles from 42 samples of metastatic thyroid tumors, metastatic breast tumors, and normal lymph node tissues. 2D DESI-MS ion images of selected molecular species allowed discrimination and visualization of specific histologic features within tissue sections, including regions of metastatic cancer, adjacent normal lymph node, and fibrosis or adipose tissues, which strongly correlated with pathologic findings. In thyroid cancer metastasis, increased relative abundances of ceramides and glycerophosphoinisitols were observed. In breast cancer metastasis, increased relative abundances of various fatty acids and specific glycerophospholipids were seen. Trends in the alterations in fatty acyl chain composition of lipid species were also observed through detailed mass spectra evaluation and chemical identification of molecular species. The results obtained demonstrate DESI-MSI as a potential clinical tool for the detection of breast and thyroid cancer metastasis in lymph nodes, although further validation is needed. Graphical Abstract Desorption electrospray ionization mass spectrometry imaging is used to differentiate metastatic cancer from adjacent lymph node tissue.

HMGA2 immunostaining is a straightforward technique which helps to distinguish pulmonary fat-forming lesions from normal adipose tissue in small biopsies: a retrospective observational study about a series of 13 lung biopsies

BackgroundA tracheobronchial lesion observed during an endoscopic examination is usually sampled by the pulmonologist and sent to the pathologist for microscopic examination. Adipocytes may be observed in the lamina propria of tracheobronchial biopsies, which may complicate diagnosis of sampled lesions because these adipose cells may be part of the lesion (lipoma or pulmonary hamartoma), but may also be a normal component of the bronchial mucosa. Because endoscopic samples frequently miss their target, adipocytes observed in such biopsies usually lead to uncertainty regarding diagnosis. Both pulmonary hamartomas and lipomas have a high frequency of translocations involving HMGA2, resulting in over expression of the fusion protein. The literature suggests that only 31% of tracheobronchial lipomas are correctly diagnosed on biopsy, sometimes leading to unnecessary aggressive surgical resection.MethodsWe performed retrospective study of tracheo-bronchial biopsies containing adipocytes using HMGA2 immunostaining in order to define their nature and to assess the diagnostic utility of this marker.ResultsIn total, 13 lesions biopsied in 12 patients and containing adipocytes were immunostained for HMGA2. Nuclear immunostaining was detected in 7 out of the 13 lesions (54%), allowing us to diagnose a lipoma or hamartoma.ConclusionHMGA2 immunostaining is an affordable and straightforward technique for accurate description of biopsies containing adipose cells. When positive, a diagnosis of benign adipose lesion can be made with confidence since well-differentiated liposarcomas have never been described in the tracheobronchial tree. Our work enabled us to diagnose a benign adipose lesion in 54% of cases, above the rate of 31% reported in the literature, based solely on morphological analysis. Overall, HMGA2 immunostaining could help pathologists to provide accurate diagnosis of tracheobronchial adipose lesions, leading to conservative treatment, for the overall benefit of patients.

Human breast adipose tissue: characterization of factors that change during tumor progression in human breast cancer

BackgroundAdipose microenvironment is involved in signaling pathways that influence breast cancer. We aim to characterize factors that are modified: 1) in tumor and non tumor human breast epithelial cell lines when incubated with conditioned media (CMs) from human breast cancer adipose tissue explants (hATT) or normal breast adipose tissue explants (hATN); 2) in hATN-CMs vs hATT-CMs; 3) in the tumor associated adipocytes vs. non tumor associated adipocytes.MethodsWe used hATN or hATT- CMs on tumor and non-tumor breast cancer cell lines. We evaluated changes in versican, CD44, ADAMTS1 and Adipo R1 expression on cell lines or in the different CMs. In addition we evaluated changes in the morphology and expression of these factors in slices of the different adipose tissues. The statistical significance between different experimental conditions was evaluated by one-way ANOVA. Tukey’s post-hoc tests were performed within each individual treatment.ResultshATT-CMs increase versican, CD44, ADAMTS1 and Adipo R1 expression in breast cancer epithelial cells. Furthermore, hATT-CMs present higher levels of versican expression compared to hATN-CMs. In addition, we observed a loss of effect in cellular migration when we pre-incubated hATT-CMs with chondroitinase ABC, which cleaves GAGs chains bound to the versican core protein, thus losing the ability to bind to CD44. Adipocytes associated with the invasive front are reduced in size compared to adipocytes that are farther away. Also, hATT adipocytes express significantly higher amounts of versican, CD44 and Adipo R1, and significantly lower amounts of adiponectin and perilipin, unlike hATN adipocytes.ConclusionsWe conclude that hATT secrete a different set of proteins compared to hATN. Furthermore, versican, a proteoglycan that is overexpressed in hATT-CMs compared to hATN-CMs, might be involved in the tumorogenic behavior observed in both cell lines employed. In addition, we may conclude that adipocytes from the tumor microenvironment show a less differentiated state than adipocytes from normal microenvironment. This would indicate a loss of normal functions in mature adipocytes (such as energy storage), in support of others that might favor tumor growth.

Do Mesenchymal Stem Cells Derived From Atypical Lipomatous Tumors Have Greater Differentiation Potency Than Cells From Normal Adipose Tissues?

The p53 protein in mesenchymal stem cells (MSCs) regulates differentiation to osteogenic or adipogenic lineage. Because p53 function is depressed in most malignancies, if MSCs in malignancy also have p53 hypofunction, differentiation therapy to osteogenic or adipogenic lineage may be an effective treatment. We therefore wished to begin to explore this idea by evaluating atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDL) cells, because murine double minute 2 (MDM2) gene amplification, which leads to p53 hypofunction, is found in almost all ALT/WDLs. We compared osteogenic and adipogenic differentiation potency between MSCs isolated and cultured from normal adipose tissues and ALT/WDLs from the same patients. During tumor resections in six patients with ALT/WDL, we analyzed 3 mL of tumor, and for comparison, we harvested a similar amount of normal-appearing subcutaneous adipose tissue from an area remote from the tumor for comparison. Adipogenic differentiation potency was quantitatively assessed using spectrometry after oil red O staining. Osteogenic differentiation potency was semiquantitatively assessed by measuring a specific colored area after alkaline phosphatase (ALP) and alizarin red S staining. ALP is related to preosseous cellular metabolism, and alizarin red is related to calcium deposits in cell culture. There were three observers for each assessment, and each assessment (including induced-differentiation and histologic analysis) was performed in duplicate. We then analyzed the mechanism of the difference of osteogenic differentiation potency using the MDM2-specific inhibitor Nutlin-3 at various concentrations. In terms of adipogenic differentiation potency, contrary to our expectations, more fatty acid droplets were observed in MSCs derived from normal fat than in MSCs derived from ALT/WDL, although we found no significant difference between MSCs derived from ALT/WDL and MSCs derived from normal fat; the mean differentiation potency values (normal adipose tissue versus ALT/WDL) (± SD) were 0.34 (SD, ± 0.13; 95% CI, 0.24-0.44) versus 0.25 (SD, ± 0.10; 95% CI, 0.18-0.33; p = 0.22). By contrast, we found greater osteogenic differentiation potency in MSCs derived from ALT/WDL than in MSCs derived from normal fat. The mean differentiation potency values (normal adipose tissue versus ALT/WDL) (±SD) based on ALP staining was 1.0 versus 17 (SD, ± 36; 95% CI, -2.8 to 38; p = 0.04). However, we found no differences based on alizarin red S staining; mean differentiation potency value (normal adipose tissue versus ALT/WDL) (± SD) was 1.0 versus 4.2 (SD, ± 4.8; 95% CI, 1.3-7.2; p = 0.58). The gap of osteogenic differentiation potency between MSCs from normal adipose tissue and ALT/WDL was decreased as MDM2-inhibitor Nutlin-3 concentration increased. MSCs derived from ALT/WDL had higher osteogenic differentiation potency based on ALP staining, which disappeared as Nutlin-3 concentration increased, suggesting that could be caused by amplified MDM2 in ALT/WDL. Future laboratory studies might mechanistically confirm the gene and protein expression, and based on the mechanism of the gap of differentiation potency, if p53 contrast between MSCs in tumor and normal tissue could be stimulated, less-toxic and more-effective differentiation therapy to MSCs in malignancies might be developed.

An unusual presentation of ventral post-traumatic pseudolipomas in a surfer: a case report

Background: Pseudolipomas are normal adipose tissues that accumulate in abnormal locations and postulate an association with trauma. Post-traumatic pseudolipomas (PTLs) are benign, soft tissue tumors that develop in various anatomic sites following acute, chronic or repetitive trauma. PTLs remain a poorly recognized and investigated clinical entity. They follow a benign course and early recognition of this clinical entity may allay anxiety in patients who suspect a more serious underlying condition or malignancy. Case presentation: We present an unusual case of a 31 year old male with a history of repetitive surfboard trauma in the past presenting with symmetric, painless soft tissue swelling of upper abdomen. Magnetic resonance imaging was consistent with Ventral PTLs. Conclusion: PTLs are a distinct clinicopathological entity but, owing to unpredictable presentations, are poorly recognized by physicians and surgeons alike. Inclusion of PTL in the differential of a lipomatous lesion can be achieved by eliciting a prior history of trauma. PTLs have not been documented to undergo malignant transformation and patient anxiety may be allayed with the diagnosis. Liposuction or surgical excision may be offered for cosmetic reasons or if symptoms arise.

Endothelial Dysfunction in Obesity.

Chronic inflammatory state in obesity causes dysregulation of the endocrine and paracrine actions of adipocyte-derived factors, which disrupt vascular homeostasis and contribute to endothelial vasodilator dysfunction and subsequent hypertension. While normal healthy perivascular adipose tissue (PVAT) ensures the dilation of blood vessels, obesity-associated PVAT leads to a change in profile of the released adipo-cytokines, resulting in a decreased vasorelaxing effect. Adipose tissue inflammation, nitric oxide (NO)-bioavailability, insulin resistance and oxidized low-density lipoprotein (oxLDL) are main participating factors in endothelial dysfunction of obesity. In this chapter, disruption of inter-endothelial junctions between endothelial cells, significant increase in the production of reactive oxygen species (ROS), inflammation mediators, which are originated from inflamed endothelial cells, the balance between NO synthesis and ROS , insulin signaling and NO production, and decrease in L-arginine/endogenous asymmetric dimethyl-L-arginine (ADMA) ratio are discussed in connection with endothelial dysfunction in obesity.

Bariatric Endocrinology, Adiposopathy, and Disorders of Regional Fat Distribution

Bariatric Endocrinology, Adiposopathy, and Disorders of Regional Fat Distribution

Optimizing fresh specimen staining for rapid identification of tumor biomarkers during surgery.

Rationale: Positive margin status due to incomplete removal of tumor tissue during breast conserving surgery (BCS) is a prevalent diagnosis usually requiring a second surgical procedure. These follow-up procedures increase the risk of morbidity and delay the use of adjuvant therapy; thus, significant efforts are underway to develop new intraoperative strategies for margin assessment to eliminate re-excision procedures. One strategy under development uses topical application of dual probe staining and a fluorescence imaging strategy termed dual probe difference specimen imaging (DDSI). DDSI uses a receptor-targeted fluorescent probe and an untargeted, spectrally-distinct fluorescent companion imaging agent topically applied to fresh resected specimens, where the fluorescence from each probe is imaged and a normalized difference image is computed to identify tumor-target distribution in the specimen margins. While previous reports suggested this approach is a promising new tool for surgical guidance, advancing the approach into the clinic requires methodical protocol optimization and further validation.Methods: In the present study, we used breast cancer xenografts and receiver operator characteristic (ROC) curve analysis to evaluate a wide range of staining and imaging parameters, and completed a prospective validation study on multiple tumor phenotypes with different target expression. Imaging fluorophore-probe pair, concentration, and incubation times were systematically optimized using n=6 tissue specimen replicates per staining condition. Resulting tumor vs. normal adipose tissue diagnostic performance were reported and staining patterns were validated via receptor specific immunohistochemistry colocalization. Optimal staining conditions were tested in receptor positive and receptor negative cohorts to confirm specificity.Results: The optimal staining conditions were found to be a one minute stain in a 200 nM probe solution (area under the curve (AUC) = 0.97), where the choice of fluorescent label combination did not significantly affect the diagnostic performance. Using an optimal threshold value determined from ROC curve analysis on a training data set, a prospective study on xenografts resulted in an AUC=0.95 for receptor positive tumors and an AUC = 0.50 for receptor negative (control) tumors, confirming the diagnostic performance of this novel imaging technique.Conclusions: DDSI provides a robust, molecularly specific imaging methodology for identifying tumor tissue over benign mammary adipose tissue. Using a dual probe imaging strategy, nonspecific accumulation of targeted probe was corrected for and tumor vs. normal tissue diagnostic potential was improved, circumventing difficulties with ex vivo tissue specimen staining and allowing for rapid clinical translation of this promising technology for tumor margin detection during BCS procedures.

Cancer-testis antigen expression in synovial sarcoma: NY-ESO-1, PRAME, MAGEA4, and MAGEA1

Synovial sarcoma (SS) is regarded as a relatively chemosensitive sarcoma, but the prognosis of advanced SSs remains poor. Here we identified highly expressed cancer-testis antigens that could be promising immunotherapy targets for SS, using a previously conducted cDNA microarray, and we assessed the clinicopathological or prognostic relationships of these antigens in SS. We compared the gene expression profiles of 11 SSs with those of 3 normal adipose tissues. Among the up-regulated cancer-testis antigens, we analyzed PRAME, MAGEA1, and MAGEA4 and another cancer-testis antigen (NY-ESO-1) together, by immunohistochemistry and real-time polymerase chain reaction in 108 SSs. Immunohistochemically, NY-ESO-1, PRAME, MAGEA4, and MAGEA1 were positive in 66 (61%), 93 (86%), 89 (82%), and 16 (15%) of 108 SSs, respectively, and 104 (96%) of 108 SSs showed the immunohistochemical expression of at least 1 of NY-ESO-1, PRAME, and MAGEA4. Moreover, the high expression of at least 1 of these 3 antigens was observed in 83% of the SSs. High expression of NY-ESO-1 and MAGEA4 was significantly correlated with the presence of necrosis and advanced clinical stage. The immunohistochemical expression of these cancer-testis antigens was not correlated with prognosis, but the coexpression of NY-ESO-1, PRAME, and MAGEA4 was significantly associated with adverse prognosis. The real-time polymerase chain reaction results were closely related to the immunohistochemical results: NY-ESO-1 (P = .0019), PRAME (P = .039), MAGEA4 (P = .0149), and MAGEA1 (P = .0766). These data support the potential utility of NY-ESO-1, PRAME, and MAGEA4 as immunotherapy targets and ancillary prognostic parameters, suggesting the possible benefit of the combined use of these cancer-testis antigens as an SS immunotherapy target.

Adipose Tissue-Derived IGFBP1 Facilitates Progression of Leukemia

We recently reported that adipose tissue functions as a reservoir for leukemia stem cells (LSCs) using a murine model of leukemia (Ye et al., Cell Stem Cell, 2016). Intriguingly, the presence of leukemic cells in adipose tissue induces increased lipolysis and the release of free fatty acids (FFA) which in turn fuels the growth of LSCs. Further, adipose tissue protects resident LSCs from chemotherapy. These findings indicate that the unique characteristics of adipose tissue may provide key insights on the growth and survival of leukemic cells. Thus, in the present study we focus on the endocrine function of adipose tissue and explore its role in leukemia development.First, to evaluate secreted factors, we applied adipokine arrays which detect 38 adipokines to leukemia serum collected at different stages of leukemia pathogenesis. Interestingly, we observed a significantly elevated level of serum IGFBP1 as soon as leukemic disease became evident at low levels (~0.5%) in marrow. IGFBP1 increased to levels approximate 200X normal at peak stages of disease burden. ELISA analyses further confirmed these observations.IGFBP1 is normally considered as a liver-derived protein. However, we did not find any changes of IGFBP1 expression in leukemic liver. Rather, we observed a significant increase in the expression of IGFBP1 in adipose tissue. IGFBP1 in conditioned medium (CM) from leukemic gonadal adipose tissue (GAT) is approximate 100X higher than naive GAT. Together, these findings suggest adipose tissue-derived IGFBP1 contributes to the increased serum IGFBP1 we detected in leukemic animals.We next examined the role of IGFBP1 in leukemia development using a neutralizing antibody. Treatment of experimental animals with anti-IGFBP1 antibody significantly decreased leukemic burden in GAT (~40% IgG treated VS. 20% Anti-IGFBP1 treated) while bone marrow (BM) and spleen leukemic engraftment remained unchanged (~40%). Further, less atrophy of adipose tissue as well as less body weight loss was seen in the IGFBP1 neutralizing antibody treated group. Consistent with this observation, serum FFA level was also reduced, suggesting less lipolysis in the IGFBP1 antagonized group. Together, these results indicate that IGFBP1 is involved in the regulation of leukemic cells homing to adipose tissue and consequently leukemia-induced lipolysis.Next we explored the mechanisms for the increased expression of IGFBP1 in adipose tissue. Studies have shown that both FGF21 and hypoxia induce IGFBP1 expression. We did not find any changes of FGF21 expression in adipose tissue or in liver, suggesting FGF21 was not involved in IGFBP1 regulation in our system. In contrast, we observed a five-fold elevation in IGFBP1 mRNA in primary adipose tissue cultured under hypoxic conditions. Studies have shown that both BM and spleen in leukemia mice are already hypoxic in early stages of leukemic development (Benito et al., Plos One, 2011). Thus, we hypothesize that tissue hypoxia may at least partially regulate IGFBP1 in leukemia. Ongoing experiments are testing this hypothesis. Additionally, inflammatory cytokines have been reported to increase IGFBP1 expression. We previously reported significantly increased levels of inflammatory cytokines in the adipose tissue of leukemic mice including TNF-α, IL1 and CSF2 (1.5X normal adipose tissue). Therefore, we hypothesize the local inflammatory cytokine production may also contribute to increased expression of IGFBP1, a theory that is also currently under investigation.IGFBP1 has recently been reported to activate osteoclasts and thus promotes bone metabolism (Wang et al., Cell Metabolism, 2015). Studies have found an increased number of osteoclasts and thus bone loss in our leukemic model (Frisch et al., Blood, 2012). We hypothesize that adipose tissue-derived IGFBP1 contributes to bone loss in leukemic mice. Ongoing experiments are testing whether antagonization of IGFBP1 in leukemic mice will rescue bone loss.Collectively, these findings suggest that adipose tissue-derived IGFBP1 facilitates progression of leukemia through regulation of adipose tissue lipolysis and may promote bone marrow colonization by leukemia cells through activation of osteoclasts. DisclosuresNo relevant conflicts of interest to declare.

Polycaprolactone nanofibrous mesh reduces foreign body reaction and induces adipose flap expansion in tissue engineering chamber.

Tissue engineering chamber technique can be used to generate engineered adipose tissue, showing the potential for the reconstruction of soft tissue defects. However, the consequent foreign body reaction induced by the exogenous chamber implantation causes thick capsule formation on the surface of the adipose flap following capsule contracture, which may limit the internal tissue expansion. The nanotopographical property and architecture of nanofibrous scaffold may serve as a promising method for minimizing the foreign body reaction. Accordingly, electrospinning porous polycaprolactone (PCL) nanofibrous mesh, a biocompatible synthetic polymer, was attached to the internal surface of the chamber for the reducing local foreign body reaction. Adipose flap volume, level of inflammation, collagen quantification, capsule thickness, and adipose tissue-specific gene expression in chamber after implantation were evaluated at different time points. The in vivo study revealed that the engineered adipose flaps in the PCL group had a structure similar to that in the controls and normal adipose tissue structure but with a larger flap volume. Interleukin (IL)-1β, IL-6, and transforming growth factor-β expression decreased significantly in the PCL group compared with the control. Moreover, the control group had much more collagen deposition and thicker capsule than that observed in the PCL group. These results indicate that the unique nanotopographical effect of electrospinning PCL nanofiber can reduce foreign body reaction in a tissue engineering chamber, which maybe a promising new method for generating a larger volume of mature, vascularized, and stable adipose tissue.

Abstract 715: Adipose tissues derived exosomal microRNAs and their variants in ovarian cancer progression

Abstract Most ovarian cancers are diagnosed at an advanced stage when the tumor is widely metastatic. The 5-year survival drops to 50% for the cancer cases that spread beyond the pelvis to the omentum. However, the mechanisms underlying the effect of omental adipose tissue on ovarian cancer progression are poorly understood. Recent studies showed that exosomes also contain non-coding RNAs such as microRNAs (miRNAs). Thus, we hypothesize that the transfer of microRNAs and their variants from ovarian cancer-associated omental adipose tissues to ovarian cancer cells via exosomes may contribute to the nearby microenvironment for ovarian cancer metastasis and cancer progression. Ion Torrent next generation sequencing was performed on miRNAs isolated and enriched from exosomes and cell lysates of ovarian cancer cell lines (OVCA), the epithelial component of microdissected omental ovarian cancer tissues (CT), normal omental adipose tissues (OMN) and ovarian cancer-associated omental adipose tissues (OMT). By integrating the miRNA expression profiles, 65 miRNAs were expressed at significant higher levels in OMT-derived exosomes compared with those in OMN-derived exosomes and OVCA-derived exosomes. A set of miRNAs (miR-32a, miR-221 and miR320a), which had been implicated in controlling cell growth and chemoresistance, was identified. Also, the Ion Torrent results were validated and exosomal transfer of OMT-derived miRNAs was confirmed in vitro. The exosomal communication between adipose tissues and ovarian cancer cells in the omental tumor microenvironment is verified. The transferable miRNAs and their variants may remain functional in the recipient ovarian cancer cells and confer more aggressive phenotypes in these cells. Citation Format: Chi Lam Au Yeung, Tetsushi Tsuruga, Ngai Na Co, Tsz-Lun Yeung, Cecilia S. Leung, Kwong K. Wong, Samuel C. Mok. Adipose tissues derived exosomal microRNAs and their variants in ovarian cancer progression. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 715.

Insulin Injection Into Lipohypertrophic Tissue: Blunted and More Variable Insulin Absorption and Action and Impaired Postprandial Glucose Control.

Lipohypertrophy (LHT) is common in insulin-treated patients but its exact impact on insulin absorption and action is unclear. In this crossover study, 13 patients with type 1 diabetes received subcutaneous abdominal injections of 0.15 units/kg insulin lispro into LHT (confirmed by examination and ultrasound) and normal adipose tissue (NAT). On one day, a euglycemic clamp was performed with two injections each into LHT and NAT, and on another day one injection per region was given before a standardized mixed meal (75 g carbohydrates), all in randomized order. Compared with NAT, LHT reduced insulin absorption (mean area under the insulin concentration curve [AUCINS0-4h] 131 vs. 165 h * mU/L [LHT vs. NAT]; Cmax 61 vs. 79 mU/L, P < 0.02, respectively) and effect (areas under glucose infusion rate [GIR] curves [AUCGIR0-4h 625 vs. 775 mg/kg, P < 0.05]) but increased intrasubject variability ([coefficient of variation] AUCINS0-4h 52 vs. 11%, Cmax 55 vs. 15%, AUCGIR0-4h 57 vs. 23%, all P < 0.01). Postprandial blood glucose (BG) concentrations were ≥26% higher with LHT (AUCBG0-5h 731 vs. 513 mg * h/dL, BGmax 199 vs. 157 mg/dL, 2-h BG 150 vs. 104 mg/dL, 5-h BG 145 vs. 81 mg/dL, all P < 0.05) and maximum concentrations occurred later. Hypoglycemia (BG ≤50 mg/dL) occurred numerically less frequently with LHT injection (two vs. six patients), whereas profound hyperglycemia (BG ≥300 mg/dL) only occurred with LHT injection (two patients). Tmax-INS did not differ between LHT and NAT in either study. Insulin absorption and action are blunted and considerably more variable with LHT injection, leading to profound deterioration in postprandial glucose control.

Generating an Engineered Adipose Tissue Flap Using an External Suspension Device.

The tissue-engineering chamber technique can generate large volumes of adipose tissue, which provides a potential solution for the complex reconstruction of large soft-tissue defects. However, major drawbacks of this technique are the foreign-body reaction and the volume limitation imposed by the chamber. In this study, the authors developed a novel tissue-engineering method using a specially designed external suspension device that generates an optimized volume of adipose flap and avoids the implantation of foreign material. The rabbits were processed using two different tissue-engineering methods, the external suspension device technique and the traditional tissue-engineering chamber technique. The adipose flaps generated by the external suspension device had a normal adipose tissue structure that was as good as that generated by the traditional tissue-engineering chamber, but the flap volume was much larger. The final volume of the engineered adipose flap grew between weeks 0 and 36 from 5.1 ml to 30.7 ml in the traditional tissue-engineering chamber group and to 80.5 ml in the external suspension device group. During the generation process, there were no marked differences between the two methods in terms of structural and cellular changes of the flap, except that the flaps in the traditional tissue-engineering chamber group had a thicker capsule at the early stage. In addition, the enlarged flaps generated by the external suspension device could be reshaped into specific shapes by the implant chamber. This minimally invasive external suspension device technique can generate large-volume adipose flaps. Combined with a reshaping method, this technique should facilitate clinical application of adipose tissue engineering.

Do very small adipocytes in subcutaneous adipose tissue (a proposed risk factor for insulin insensitivity) have a fetal origin?

Summary Background & aims Previous studies have shown that fetal life malnutrition affects preferences for fat deposition in the body thereby predisposing for visceral adipocity and associated disorders in glucose-insulin regulation. In this study, we aimed to test the hypotheses that late-gestation undernutrition 1) has long-term differential impacts on development, expandability and metabolic features in subcutaneous as compared to perirenal and mesenteric adipose tissues, which 2) will predispose for visceral obesity upon exposure to an obesogenic diet in early postnatal life. Methods Twin-bearing last trimester ewes received diets supplying 100% (NORM) or 50% (LOW) of protein and energy requirements. Lambs received moderate, low-fat (CONV) or high-carbohydrate-high-fat (HCHF) diets from 3-days until 6-months of age (just after puberty), and then half the lambs (including all males) were sacrificed. Remaining animals (exclusively females) received a low-fat, grass-based diet until sacrificed at 2-years of age (adulthood). In subcutaneous, perirenal and mesenteric fat, energy metabolism related gene expressions and fatty acid composition were determined. Histological evaluations were performed of subcutaneous and perirenal fat. The late-gestation undernutrition reduced whole-body insulin sensitivity and increased the risk of obesity-induced mesenteric adiposity in the sheep used in the experiment. Results A deviating morphology of subcutaneous adipose tissue with greater occurrence of very small adipocytes ( Conclusions The present study showed that greater preponderance of very small adipocytes, increased collagen infiltration and reduced subcutaneous lipid accumulation ability, as well as altered perirenal fat preferences for accumulation of C14:0 can have a fetal origin. Disturbance of normal (subcutaneous) adipose tissue development may play a key role in linking fetal malnutrition to disease risk later in life.

Raptor/mTORC1 loss in adipocytes causes progressive lipodystrophy and fatty liver disease.

ObjectiveNormal adipose tissue growth and function is critical to maintaining metabolic homeostasis and its excess (e.g. obesity) or absence (e.g. lipodystrophy) is associated with severe metabolic disease. The goal of this study was to understand the mechanisms maintaining healthy adipose tissue growth and function.MethodsAdipose tissue senses and responds to systemic changes in growth factor and nutrient availability; in cells mTORC1 regulates metabolism in response to growth factors and nutrients. Thus, mTORC1 is poised to be a critical intracellular regulator of adipocyte metabolism. Here, we investigate the role of mTORC1 in mature adipocytes by generating and characterizing mice in which the Adiponectin-Cre driver is used to delete floxed alleles of Raptor, which encodes an essential regulatory subunit of mTORC1.ResultsRaptorAdipoq-cre mice have normal white adipose tissue (WAT) mass for the first few weeks of life, but soon thereafter develop lipodystrophy associated with hepatomegaly, hepatic steatosis, and insulin intolerance. RaptorAdipoq-cre mice are also resistant to becoming obese when consuming a high fat diet (HFD). Resistance to obesity does not appear to be due to increased energy expenditure, but rather from failed adipose tissue expansion resulting in severe hepatomegaly associated with hyperphagia and defective dietary lipid absorption. Deleting Raptor in WAT also decreases C/EBPα expression and the expression of its downstream target adiponectin, providing one possible mechanism of mTORC1 function in WAT.ConclusionsmTORC1 activity in mature adipocytes is essential for maintaining normal adipose tissue growth and its selective loss in mature adipocytes leads to a progressive lipodystrophy disorder and systemic metabolic disease that shares many of the hallmarks of human congenital generalized lipodystrophy.

Integrative Genomic Analyses Yield Cell-Cycle Regulatory Programs with Prognostic Value.

Liposarcoma is the second most common form of sarcoma, which has been categorized into four molecular subtypes, which are associated with differential prognosis of patients. However, the transcriptional regulatory programs associated with distinct histologic and molecular subtypes of liposarcoma have not been investigated. This study uses integrative analyses to systematically define the transcriptional regulatory programs associated with liposarcoma. Likewise, computational methods are used to identify regulatory programs associated with different liposarcoma subtypes, as well as programs that are predictive of prognosis. Further analysis of curated gene sets was used to identify prognostic gene signatures. The integration of data from a variety of sources, including gene expression profiles, transcription factor-binding data from ChIP-Seq experiments, curated gene sets, and clinical information of patients, indicated discrete regulatory programs (e.g., controlled by E2F1 and E2F4), with significantly different regulatory activity in one or multiple subtypes of liposarcoma with respect to normal adipose tissue. These programs were also shown to be prognostic, wherein liposarcoma patients with higher E2F4 or E2F1 activity associated with unfavorable prognosis. A total of 259 gene sets were significantly associated with patient survival in liposarcoma, among which > 50% are involved in cell cycle and proliferation. These integrative analyses provide a general framework that can be applied to investigate the mechanism and predict prognosis of different cancer types.