Adipose Tissue Extracellular Matrix Research Articles

Role of Perivascular Adipose Tissue in Vascular Physiology and Pathology.

Blood pressure (BP) regulation is a complex homeostatic process involving multiple organ systems, including the cardiovascular, renal, and central and peripheral nervous systems.1 Inability to properly regulate BP can result in the development of hypertension, which is associated with an increased risk of stroke, myocardial infarction, and cardiac and renal failure,2–4 and is the leading determinant of risk of death worldwide.5 In addition to genetic and environmental factors known to play a role in the development of hypertension,6 body weight and obesity are highly correlated with hypertension in humans.7,8 This is particularly alarming given the increased prevalence of obesity, which now affects 1 in 3 people in the United States.9 The close association between obesity, hypertension, and other cardiovascular disorders suggests an important role for adipose tissue (AT) in the regulation of vascular tone and BP. Until the mid 1900s, AT was considered to be a form of connective tissue with the primary function of storing energy in the form of lipids.10 However, AT is now recognized to be an important endocrine organ that can secrete polypeptides and metabolites, known as adipokines, which are involved in the normal regulation of various physiological processes, including BP regulation and vascular function.10,11 In the setting of obesity, AT undergoes complex remodeling. This is marked by a significant increase in tissue mass, through adipocyte hyperplasia and hypertrophy. Changes in structural and cellular composition also occur, including changes in AT extracellular matrix, composition of lipid droplets, and infiltration of immune cells such as macrophages and lymphocytes, which results in low-grade inflammation.10,11 Most importantly, obesity shifts the secretory profile of AT, which in turn contributes to the dysregulation of BP and eventual development of hypertension.12 This is thought …

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.

Aberrant Epicardial Adipose Tissue Extracellular Matrix Remodeling in Patients with Severe Ischemic Cardiomyopathy: Insight from Comparative Quantitative Proteomics

There is ample evidence indicating that epicardial adipose tissue (EAT) volume and thickness is positively associated with coronary artery disease (CAD). However, the exact pathological changes in the human EAT after myocardial ischemia remains largely unclear. In the current study, we applied a comparative quantitative proteomics to elucidate the altered biological processes in the EAT of ischemic cardiomyopathy (ICM) patients. A total of 1649 proteins were successfully quantified in our study, among which 165 proteins were significantly changed (ratio <0.8 or >1.2 fold and p < 0.05 in both repetitions) in EAT of ICM individuals. Gene ontology (GO) enrichment analysis revealed that cardiac structure and cellular metabolism were over-represented among these regulated proteins. The hypertrophic cardiomyopathy, adrenergic signaling in cardiomyocytes, extracellular matrix (ECM)-receptor interaction, phagosome, Glycolysis/Gluconeogenesis, and PPAR signaling pathway were highlighted by the KEGG PATHWAY analysis. More importantly, we found that the proteins responsible for extracellular matrix organization were dramatically increased in EAT of ICM patients. In addition, the picrosirius red (PSR) staining results showed that the collagen fiber content was prominently increased, which indicated the EAT of ICM individuals underwent extracellular matrix remodeling and ERK1/2 activation maybe responsible for these pathological changes partially.

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.

Extracellular matrix remodeling and transforming growth factor-β signaling abnormalities induced by lamin A/C variants that cause lipodystrophy

Mutations in the lamin A/C gene encoding nuclear lamins A and C (lamin A/C) cause familial partial lipodystrophy type 2 (FPLD2) and related lipodystrophy syndromes. These are mainly characterized by redistribution of adipose tissue associated with insulin resistance. Several reports suggest that alterations in the extracellular matrix of adipose tissue leading to fibrosis play a role in the pathophysiology of lipodystrophy syndromes. However, the extent of extracellular matrix alterations in FPLD2 remains unknown. We show significantly increased fibrosis and altered expression of genes encoding extracellular matrix proteins in cervical subcutaneous adipose tissue from a human subject with FLPD2. Similar extracellular matrix alterations occur in adipose tissue of transgenic mice expressing an FPLD2-causing human lamin A variant and in cultured fibroblasts from human subjects with FPLD2 and related lipodystrophies. These abnormalities are associated with increased transforming growth factor-β signaling and defects in matrix metalloproteinase 9 activity. Our data demonstrate that lamin A/C gene mutations responsible for FPLD2 and related lipodystrophies are associated with transforming growth factor-β activation and an extracellular matrix imbalance in adipose tissue, suggesting that targeting these alterations could be the basis of novel therapies.

Comparative study of adipose-derived stem cells and bone marrow-derived stem cells in similar microenvironmental conditions

Mesenchymal stem cells (MSCs), which were first isolated from the bone marrow, are now being extracted from various other tissues in the body, including the adipose tissue. The current study presents systematic evidence of how the adipose tissue-derived stem cells (ASCs) and bone marrow-derived mesenchymal stem cells (Bm-MSCs) behave when cultured in specific pro-adipogenic microenvironments. The cells were first characterized and identified as MSCs in terms of their morphology, phenotypic expression, self-renewal capabilities and multi-lineage potential. Subsequently, the proliferation and gene expression profiles of the cell populations cultured on two-dimensional (2D) adipose tissue extracellular matrix (ECM)-coated tissue culture plastic (TCP) and in three-dimensional (3D) AlgiMatrix® microenvironments were analyzed. Overall, it was found that adipogenesis was triggered in both cell populations due to the presence of adipose tissue ECM. However, in 3D microenvironments, ASCs and Bm-MSCs were predisposed to the adipogenic and osteogenic lineages respectively. Overall, findings from this study will contribute to ongoing efforts in adipose tissue engineering as well as provide new insights into the role of the ECM and cues provided by the immediate microenvironment for stem cell differentiation.

Increased Interleukin-32 Levels in Obesity Promote Adipose Tissue Inflammation and Extracellular Matrix Remodeling: Effect of Weight Loss.

Interleukin (IL)-32 is a recently described cytokine involved in the regulation of inflammation. We aimed to explore whether IL-32 could function as an inflammatory and angiogenic factor in human obesity and obesity-associated type 2 diabetes. Samples obtained from 90 subjects were used in the study. Obese patients exhibited higher expression levels of IL-32 in visceral adipose tissue (AT) as well as in subcutaneous AT and peripheral blood mononuclear cells. IL32 was mainly expressed by stromovascular fraction cells, and its expression was significantly enhanced by inflammatory stimuli and hypoxia, whereas no changes were found after the incubation with anti-inflammatory cytokines. The addition of exogenous IL-32 induced the expression of inflammation and extracellular matrix-related genes in human adipocyte cultures, and IL32-silenced adipocytes showed a downregulation of inflammatory genes. Furthermore, adipocyte-conditioned media obtained from obese patients increased IL32 gene expression in human monocyte cultures, whereas the adipocyte-conditioned media from lean volunteers had no effect on IL32 mRNA levels. These findings provide evidence, for the first time, about the inflammatory and remodeling properties of IL-32 in AT, implicating this cytokine in obesity-associated comorbidities.

Immunomagnetic Separation of Fat Depot-specific Sca1high Adipose-derived Stem Cells (ASCs).

The isolation of adipose-derived stem cells (ASCs) is an important method in the field of adipose tissue biology, adipogenesis, and extracellular matrix (ECM) remodeling. In vivo, ECM-rich environment consisting of fibrillar collagens provides a structural support to adipose tissues during the progression and regression of obesity. Physiological ECM remodeling mediated by matrix metalloproteinases (MMPs) plays a major role in regulating adipose tissue size and function(1,2). The loss of physiological collagenolytic ECM remodeling may lead to excessive collagen accumulation (tissue fibrosis), macrophage infiltration, and ultimately, a loss of metabolic homeostasis including insulin resistance(3,4). When a phenotypic change of the adipose tissue is observed in gene-targeted mouse models, isolating primary ASCs from fat depots for in vitro studies is an effective approach to define the role of the specific gene in regulating the function of ASCs. In the following, we define an immunomagnetic separation of Sca1(high) ASCs.

Preparation, Characterization, and Clinical Implications of Human Decellularized Adipose Tissue Extracellular Matrix (hDAM): A Comprehensive Review.

Fat grafting is commonly employed by plastic and reconstructive surgeons to address contour abnormalities and soft-tissue defects; however, because retention rates and thus volume filling effects are unpredictable, there is a search for new and innovative approaches. Initial studies on the use of human decellularized adipose tissue extracellular matrix (hDAM) show promise for its use not only in tissue engineering, but also in fat grafting. In this review, we examine and analyze the literature for the preparation, characterization, and use of hDAM and its derivatives in tissue engineering and plastic surgery applications. All studies reviewed involve physical, chemical, and/or biological treatment stages for the preparation of hDAM; however a distinction should be made between detergent and nondetergent-based processing, the latter of which appears to preserve the native integrity of the hDAM while most-efficiently achieving complete decellularization. Methods of hDAM characterization vary among groups and included simple and immunohistochemical staining, biochemical assays, 3-dimensional (3D) imaging, and mechano-stress testing, all of which are necessary to achieve a comprehensive description of this novel tissue. Finally, we examine the various preclinical models utilized to optimize hDAM performance, which primarily include the addition of adipose-derived stem cells or cross-linking agents. Overall, hDAM appears to be a promising adjunct in fat-grafting applications or even possibly as a stand-alone soft-tissue filler with off-the-shelf potential for commercial applications.

Obesity-induced remodeling of the adipose tissue elastin network is independent of the metalloelastase MMP-12

The extracellular matrix (ECM) plays important roles in maintaining adequate adipose tissue function and in metabolic regulation. Here we have examined the organization of a relatively unexplored adipose tissue ECM component, elastin and its response to diet induced obesity in mice. Additionally, we have explored the regulation and requirement of macrophage metalloelastase, MMP-12, in adipose tissue ECM remodeling in obesity. In visceral fat depots, elastin fibers form a mesh-like net that becomes denser with diet-induced obesity. In contrast, the elastin fibers in subcutaneous adipose depots are more linear in organization, and are tightly associated with adipose tissue macrophages (ATMs). We found that Mmp12 is produced predominantly by ATMs and can be induced with both short- and long-term high fat diet challenge and rapid remodeling induced by lipolysis. This contrasts with Mmp14 and Timp1 which are further induced only after chronic obesity in non-ATM populations. We examined obese transgenic Mmp12−/− mice and found an increase in gene expression of ECM genes with diet-induced obesity, but showed few significant differences in metabolic parameters, elastin matrix density, or in adipose tissue inflammation. Together, these studies reveal the architecture and diet-induced regulation of the elastin matrix and suggest that MMP-12 is not required for elastin matrix remodeling or for the metabolic dysfunction that occurs with obesity.

Osteopontin deletion prevents the development of obesity and hepatic steatosis via impaired adipose tissue matrix remodeling and reduced inflammation and fibrosis in adipose tissue and liver in mice.

Osteopontin (OPN) is a multifunctional extracellular matrix (ECM) protein involved in multiple physiological processes. OPN expression is dramatically increased in visceral adipose tissue in obesity and the lack of OPN protects against the development of insulin resistance and inflammation in mice. We sought to unravel the potential mechanisms involved in the beneficial effects of the absence of OPN. We analyzed the effect of the lack of OPN in the development of obesity and hepatic steatosis induced by a high-fat diet (HFD) using OPN-KO mice. OPN expression was upregulated in epididymal white adipose tissue (EWAT) and liver in wild type (WT) mice with HFD. OPN-KO mice had higher insulin sensitivity, lower body weight and fat mass with reduced adipose tissue ECM remodeling and reduced adipocyte size than WT mice under a HFD. Reduced MMP2 and MMP9 activity was involved in the decreased ECM remodeling. Crown-like structure number in EWAT as well as F4/80-positive cells and Emr1 expression in EWAT and liver increased with HFD, while OPN-deficiency blunted the increase. Moreover, our data show for the first time that OPN-KO under a HFD mice display reduced fibrosis in adipose tissue and liver, as well as reduced oxidative stress in adipose tissue. Gene expression of collagens Col1a1, Col6a1 and Col6a3 in EWAT and liver, as well as the profibrotic cytokine Tgfb1 in EWAT were increased with HFD, while OPN-deficiency prevented this increase. OPN deficiency prevented hepatic steatosis via reduction in the expression of molecules involved in the onset of fat accumulation such as Pparg, Srebf1, Fasn, Mogat1, Dgat2 and Cidec. Furthermore, OPN-KO mice exhibited higher body temperature and improved BAT function. The present data reveal novel mechanisms of OPN in the development of obesity, pointing out the inhibition of OPN as a promising target for the treatment of obesity and fatty liver.

Fat depot-specific gene signature and ECM remodeling of Sca1high adipose-derived stem cells

Stem cell antigen-1 (Sca1 or Ly6A/E) is a cell surface marker that is widely expressed in mesenchymal stem cells, including adipose-derived stem cells (ASCs). We hypothesized that the fat depot-specific gene signature of Sca1high ASCs may play the major role in defining adipose tissue function and extracellular matrix (ECM) remodeling in a depot-specific manner. Herein we aimed to characterize the unique gene signature and ECM remodeling of Sca1high ASCs isolated from subcutaneous (inguinal) and visceral (epididymal) adipose tissues. Sca1high ASCs are found in the adventitia and perivascular areas of adipose tissues. Sca1high ASCs purified with magnetic-activated cell sorting (MACS) demonstrate dendrite or round shape with the higher expression of cytokines and chemokines (e.g., Il6, Cxcl1) and the lower expression of a glucose transporter (Glut1). Subcutaneous and visceral fat-derived Sca1high ASCs particularly differ in the gene expressions of adhesion and ECM molecules. While the expression of the major membrane-type collagenase (MMP14) is comparable between the groups, the expressions of secreted collagenases (MMP8 and MMP13) are higher in visceral Sca1high ASCs than in subcutaneous ASCs. Consistently, slow but focal MMP-dependent collagenolysis was observed with subcutaneous adipose tissue-derived vascular stromal cells, whereas rapid and bulk collagenolysis was observed with visceral adipose tissue-derived cells in MMP-dependent and -independent manners. These results suggest that the fat depot-specific gene signatures of ASCs may contribute to the distinct patterns of ECM remodeling and adipose function in different fat depots.

Human decellularized adipose tissue scaffold as a model for breast cancer cell growth and drug treatments

Human adipose tissue extracellular matrix, derived through decellularization processing, has been shown to provide a biomimetic microenvironment for adipose tissue regeneration. This study reports the use of human adipose tissue-derived extracellular matrix (hDAM) scaffolds as a three-dimensional cell culturing system for the investigation of breast cancer growth and drug treatments. The hDAM scaffolds have similar extracellular matrix composition to the microenvironment of breast tissues. Breast cancer cells were cultured in hDAM scaffolds, and cell proliferation, migration, morphology, and drug responses were investigated. The growth profiles of multiple breast cancer cell lines cultured in hDAM scaffolds differed from the growth of those cultured on two-dimensional surfaces and more closely resembled the growth of xenografts. hDAM-cultured breast cancer cells also differed from those cultured on two-dimensional surfaces in terms of cell morphology, migration, expression of adhesion molecules, and sensitivity to drug treatment. Our results demonstrated that the hDAM system provides breast cancer cells with a biomimetic microenvironment in vitro that more closely mimics the in vivo microenvironment than existing two-dimensional and Matrigel three-dimensional cultures do, and thus can provide vital information for the characterization of cancer cells and screening of cancer therapeutics.

Combining decellularized human adipose tissue extracellular matrix and adipose-derived stem cells for adipose tissue engineering

Repair of soft tissue defects resulting from lumpectomy or mastectomy has become an important rehabilitation process for breast cancer patients. This study aimed to provide an adipose tissue engineering platform for soft tissue defect repair by combining decellularized human adipose tissue extracellular matrix (hDAM) and human adipose-derived stem cells (hASCs). To derive hDAM incised human adipose tissues underwent a decellularization process. Effective cell removal and lipid removal were proved by immunohistochemical analysis and DNA quantification. Scanning electron microscopic examination showed a three-dimensional nanofibrous architecture in hDAM. The hDAM included collagen, sulfated glycosaminoglycan, and vascular endothelial growth factor, but lacked major histocompatibility complex antigen I. hASC viability and proliferation on hDAM were proven in vitro. hDAM implanted subcutaneously in Fischer rats did not cause an immunogenic response, and it underwent remodeling, as indicated by host cell infiltration, neovascularization, and adipose tissue formation. Fresh fat grafts (Coleman technique) and engineered fat grafts (hDAM combined with hASCs) were implanted subcutaneously in nude rats. The implanted engineered fat grafts maintained their volume for 8weeks, and the hASCs contributed to adipose tissue formation. In summary, the combination of hDAM and hASCs provides not only a clinically translatable platform for adipose tissue engineering, but also a vehicle for elucidating fat grafting mechanisms.

From mice to men – mouse models in obesity research: What can we learn?

Obesity has become a world-wide epidemic and is associated with diseases such as diabetes, dyslipidaemia, cardiovascular disease and certain types of cancers. Understanding the adipose tissue developmental process, involving adipogenesis, angiogenesis and extracellular matrix remodelling, is therefore crucial to reveal the pathobiology of obesity. Experimental mouse models are extensively used to gain new insights into these processes and to evaluate the role of new key players, in particular proteolytic system components, in adipose tissue development and obesity. In this paper, we will review available in vitro and in vivo murine models of obesity and discuss their value in understanding the mechanisms contributing to obesity.

Experimental study on adipose tissue engineering with human adipose-derived stem cells and adipose tissue extracellular matrix scaffold

Objective To explore the possibility of building tissue-engineered adipose tissue with human adipose-derived stem cells (ADSCs) and adipose tissue extracellular matrix (ECM) scaffold,and provide experimental basis for clinical application of tissue-engineered adipose tissue for the repair of soft tissue defects.Methods ADSCs were isolated from adipose tissue by liposuction with the method of enzymatic digestion.The cells were induced for three-line differentiation and marked with DiI.Human ECM was extracted from adipose tissue obtained by liposuction.The ECM was freeze-dried,sterilized and crushed to powders.The surface characteristics of ECM were observed under the electron microscopy in vitro.The ADSCs were adhered to ECM powers,and the feasibility of ECM powers as scaffold was explorted.Human ADSCs in a density of 2 × 109/L were collected,and mixed them with ECM powers.They were transplanted subcutaneously into nude mice,and the opposite side of the same mice transplanted with scaffold only served as control group.There were 6 mice in total,and each side was transplanted by 0.5 ml.At 8th week post-transplantation,the mice were sacrificed and the implanted tissue were taken to record the wet weight,The hematoxylin and eosin (HE) sections and red oil O staining were detected.Two-sample test of SPSS 13.0 was used for statistical comparison between wet-determination.Results The ADSCs and human ECM powder were obtained successfully from adipose tissue.The ADSCs could differentiate into adipose cells,bone cells and chondrocytes.Scanning election microscopy (SEM) images showed that the powers had porous structure to which ADSCs could adhere easily,with the adhesion rate being (89.87 ±2.59)％.Eight weeks after transplantation,both experimental and control groups formed new tissues.There were significant differences between two groups ( P ＜ 0.05 ) in the wet weight.HE and red oil O staining confirmed that the experimental group could form mature adipose tissue.Conclusion ADSCs and human ECM scaffold could form tissue-engineered adipose tissuein vivo.It can be used as an ideal method to construct tissue-engineered adipose tissue. Key words: Adipose-derived stem cells; Extracellular matrix; Scaffold; Tissue engineering

Different Roles of Mast Cells in Obesity and Diabetes: Lessons from Experimental Animals and Humans

Mast cells (MCs) play an important role in allergic hyperresponsiveness and in defending microorganism infections. Recent studies of experimental animals and humans have suggested that MCs participate in obesity and diabetes. MC distribution and activities in adipose tissues may vary, depending on the locations of different adipose tissues. In addition to releasing inflammatory mediators to affect adipose tissue extracellular matrix remodeling and to promote inflammatory cell recruitment and proliferation, MCs directly and indirectly interact and activate adipose tissue cells, including adipocytes and recruited inflammatory cells. Plasma MC protease levels are significantly higher in obese patients than in lean subjects. Experimental obese animals lose body weight after MC inactivation. MC functions in diabetes are even more complicated, and depend on the type of diabetes and on different diabetic complications. Both plasma MC proteases and MC activation essential immunoglobulin E levels are significant risk factors for human pre-diabetes and diabetes mellitus. MC stabilization prevents diet-induced diabetes and improves pre-established diabetes in experimental animals. MC depletion or inactivation can improve diet-induced type 2 diabetes and some forms of type 1 diabetes, but also can worsen other forms of type 1 diabetes, at least in experimental animals. Observations from animal and human studies have suggested beneficial effects of treating diabetic patients with MC stabilizers. Some diabetic patients may benefit from enhancing MC survival and proliferation – hypotheses that merit detailed basic researches and clinical studies.

Construction of scaffold with human extracellular matrix from adipose tissue

To investigate the feasibility of constructing scaffold for tissue engineering with human extracellular matrix from adipose tissue. Fresh human adipose tissue was obtained by liposuction in 7 women who undergone liposuction. One part of the fat was used to isolate the adipose-derived stem cells (ADSCs), the other part was used to extract human extracellular matrix powder. After removing blood and oil components, the tissue was homogenized, centrifuged, freeze-dried, and crushed to powder by instrument. The structure of human ECM powder was observed with electron microscopy. The ADSCs were seeded and attached to the human extracellular matrix powder before and after labeled with fluorescent DiI, respectively. The adhesion rate was detected. The adhesion and growth of ADSCs were observed with Fluorescence microscope. The adhesion rate before and after DiI labeling was analyzed statistically with two-sample test of SPSS 13.0. The ADSCs and human extracellular matrix powder were obtained successfully from adipose tissue. The ADSCs could be differentiated into adipose cells, bone cells and chondrocytes. SEM images showed that the power had both rugged and smooth surface with a porous structure characteristics. ADSCs could adhere to the scaffold easily, and the adhesion rate was (88.81 +/- 4.81)% and (86.48 +/- 4.58)% before and after DiI labeling. There was no difference between two groups. DiI labeled ADSCs were adhered to extracellular matrix scaffold and could grow in good condition. Human adipose tissue extracellular matrix powder was easy to obtain, with diversity in size and shape which provided excellent substrates for cell adhesion and growth. It could be an ideal adipose tissue engineering scaffold.

Adipose Tissue Extracellular Matrix and Vascular Abnormalities in Obesity and Insulin Resistance

Insulin resistance is associated with inflammation, fibrosis, and hypoxia in adipose tissue. This study was intended to better characterize the extracellular matrix (ECM) and vascularity of insulin-resistant adipose tissue. Adipose expression of collagens, elastin, and angiogenic factors was assessed using real-time RT-PCR and immunohistochemistry (IHC) in abdominal sc adipose tissue. Adipocyte-macrophage coculture experiments examined the effects of polarized macrophages on adipose ECM gene expression, and the effects of collagens were measured in an angiogenesis assay. A total of 74 nondiabetic subjects participated at a University Clinical Research Center. Interventions included baseline adipose biopsy and measurement of insulin sensitivity. Outcome measures included characterization of vascularity and ECM in adipose tissue. CD31 (an endothelial marker) mRNA showed no significant correlation with body mass index or insulin sensitivity. In a subgroup of 17 subjects (nine obese, eight lean), CD31-positive capillary number in obese was decreased by 58%, whereas larger vessels were increased by 70%, accounting for the lack of change in CD31 expression with obesity. Using IHC, obese (compared with lean) subjects had decreased elastin and increased collagen V expression, and adipocytes cocultured with M2 macrophages had reduced elastin and increased collagen V expression. In obese subjects, collagen V was colocalized with large blood vessels, and the addition of collagen V to an angiogenesis assay inhibited endothelial budding. The adipose tissue from obese/insulin-resistant subjects has fewer capillaries and more large vessels as compared with lean subjects. The ECM of adipose tissue may play an important role in regulating the expandability as well as angiogenesis of adipose tissue.

Comparison of Three Methods for the Derivation of a Biologic Scaffold Composed of Adipose Tissue Extracellular Matrix

Extracellular matrix (ECM)-based scaffold materials have been used successfully in both preclinical and clinical tissue engineering and regenerative medicine approaches to tissue reconstruction. Results of numerous studies have shown that ECM scaffolds are capable of supporting the growth and differentiation of multiple cell types in vitro and of acting as inductive templates for constructive tissue remodeling after implantation in vivo. Adipose tissue represents a potentially abundant source of ECM and may represent an ideal substrate for the growth and adipogenic differentiation of stem cells harvested from this tissue. Numerous studies have shown that the methods by which ECM scaffold materials are prepared have a dramatic effect upon both the biochemical and structural properties of the resultant ECM scaffold material as well as the ability of the material to support a positive tissue remodeling outcome after implantation. The objective of the present study was to characterize the adipose ECM material resulting from three methods of decellularization to determine the most effective method for the derivation of an adipose tissue ECM scaffold that was largely free of potentially immunogenic cellular content while retaining tissue-specific structural and functional components as well as the ability to support the growth and adipogenic differentiation of adipose-derived stem cells. The results show that each of the decellularization methods produced an adipose ECM scaffold that was distinct from both a structural and biochemical perspective, emphasizing the importance of the decellularization protocol used to produce adipose ECM scaffolds. Further, the results suggest that the adipose ECM scaffolds produced using the methods described herein are capable of supporting the maintenance and adipogenic differentiation of adipose-derived stem cells and may represent effective substrates for use in tissue engineering and regenerative medicine approaches to soft tissue reconstruction.