Fraction Of Adipose Tissue Research Articles

Трансплантация аутологичных клеток стромально-васкулярной фракции жировой ткани при тяжелых местных лучевых поражениях кожи, вызванных действием рентгеновского излучения

Purpose: To investigate the effectiveness of autologous cells of stromal vascular fraction of adipose tissue in severe local radiation skin injuries after the
 exposure of rats to X-rays.
 Material and methods: Experiments were performed on Wistar rats, weighing 200–230 g. Rats were exposed locally in iliolumbar region using X-ray
 machine LNC-268 (RAP 100-10) at a dose of 110 Gy (30 kV tube voltage, current 6.1 mA, thick Al filter 0.1 mm), dose rate: 17.34 Gy/min. Area of the
 irradiation field was 8.2–8.5 cm2. Transplantation of autologous cells of stromal vascular fraction (SVFC) of adipose tissue was carried out on 21st or 35th
 days after irradiation. SVFC isolation was performed by means of enzymatic treatment of adipose tissue. SVFC suspension was administered subcutaneously
 at a dose of 1×106 cells per injection around the radiation ulcers.The severity of radiation damage to the skin and the effects of cellular therapy were evaluated
 in the dynamics of clinical manifestations, with the help of plane geometry and pathomorphometry.
 Results: It was found that by the 17–25th day after irradiation radiation ulcers were formedon rat skin. In the control group of animalsulcers persisted
 throughout the observation period of more than 3 months. The area of ulcers was 1,87 ± 0,35 cm2 and 1.52 ± 0.24 cm2 at 83th and 90th days after irradiation,
 respectively. In animals of the experimental group, with autologous stromal vascular fraction of adipose tissue, was significant decrease in ulceration the
 area in comparison to control animals. In 80 % of the rats treated with SVFC on 21st day after exposure, to the 90th day after irradiation complete healing
 of ulcers occurred with the formation of atrophic scar at the site of radiation injuries. These clinical observations and planimetric were correlated with the
 results of histomorphometry.
 Conclusion: Transplantation autologous SVFC of adipose tissue contributes to accelerate the healing of radiation ulcers after local x-ray exposure in the
 experiment, indicating that the prospects of using adipose tissue cell products for the treatment of severe local radiation injuries.

Evaluation of the stromal vascular fraction of adipose tissue as the basis for a stem cell-based tissue-engineered vascular graft

ObjectiveOne of the rate-limiting barriers within the field of vascular tissue engineering is the lengthy fabrication time associated with expanding appropriate cell types in culture. One particularly attractive cell type for this purpose is the adipose-derived mesenchymal stem cell (AD-MSC), which is abundant and easily harvested from liposuction procedures. Even this cell type has its drawbacks, however, including the required culture period for expansion, which could pose risks of cellular transformation or contamination. Eliminating culture entirely would be ideal to avoid these concerns. In this study, we used the raw population of cells obtained after digestion of human liposuction aspirates, known as the stromal vascular fraction (SVF), as an abundant, culture-free cell source for tissue-engineered vascular grafts (TEVGs). MethodsSVF cells and donor-paired cultured AD-MSCs were first assessed for their abilities to differentiate into vascular smooth muscle cells (SMCs) after angiotensin II stimulation and to secrete factors (eg, conditioned media) that promote SMC migration. Next, both cell types were incorporated into TEVG scaffolds, implanted as an aortic graft in a Lewis rat model, and assessed for their patency and composition. ResultsIn general, the human SVF cells were able to perform the same functions as AD-MSCs isolated from the same donor by culture expansion. Specifically, cells within the SVF performed two important functions; namely, they were able to differentiate into SMCs (SVF calponin expression: 16.4% ± 7.7% vs AD-MSC: 19.9%% ± 1.7%) and could secrete promigratory factors (SVF migration rate relative to control: 3.1 ± 0.3 vs AD-MSC: 2.5 ± 0.5). The SVF cells were also capable of being seeded within biodegradable, elastomeric, porous scaffolds that, when implanted in vivo for 8 weeks, generated patent TEVGs (SVF: 83% patency vs AD-MSC: 100% patency) populated with primary vascular components (eg, SMCs, endothelial cells, collagen, and elastin). ConclusionsHuman adipose tissue can be used as a culture-free cell source to create TEVGs, laying the groundwork for the rapid production of cell-seeded grafts.

The fractionation of adipose tissue procedure to obtain stromal vascular fractions for regenerative purposes.

Autologous adipose tissue transplantation is clinically used to reduce dermal scarring and to restore volume loss. The therapeutic benefit on tissue damage more likely depends on the stromal vascular fraction of adipose tissue than on the adipocyte fraction. This stromal vascular fraction can be obtained by dissociation of adipose tissue, either enzymatically or mechanical. Enzymatic dissociation procedures are time-consuming and expensive. Therefore, we developed a new inexpensive mechanical dissociation procedure to obtain the stromal vascular fraction from adipose tissue in a time sparing way, which is directly available for therapeutic injection. This mechanical dissociation procedure is denoted as the fractionation of adipose tissue (FAT) procedure. The FAT procedure was performed in eleven patients. The composition of the FAT-stromal vascular fraction was characterized by immunohistochemistry. Adipose derived stromal cells isolated from the FAT-stromal vascular fraction were compared with adipose derived stromal cells isolated from nondissociated adipose tissue (control) for their CD-surface marker expression, differentiation and colony forming unit capacity. Case reports demonstrated the therapeutic effect of the FAT-stromal vascular fraction. The FAT-stromal vascular fraction is an enrichment of extracellular matrix containing a microvasculature and culturable adipose derived stromal cells. Adipose derived stromal cells isolated from FAT-stromal vascular fraction did not differ from adipose derived stromal cells isolated from the control group in CD-surface marker expression, differentiation and colony forming unit capacity. The FAT procedure is a rapid effective mechanical dissociation procedure to generate FAT-stromal vascular fraction ready for injection with all its therapeutic components of adipose tissue: it contains culturable adipose derived stromal cells embedded in their natural supportive extracellular matrix together with the microvasculature.

Fat and Stromal Vascular Fraction of Adipose Tissue in Reconstructive and Regenerative Surgery: 5 Years Experience

BACKGROUND The aim of this study is to estimate possible ways of using fatty tissue and its cell derivatives in reconstructive and regenerative surgery. MATERIALS AND METHODS: Since 2010, fat grafting was performed in 140 patients. Posttraumatic, postoperative, and postirradiated contour deformities were treated in 74 cases (breast, 31; head and neck, 27; and other localizations, 16). In 61 patients, fat was injected to promote chronic wound healing (venous ulcers, 22; diabetic ulcers, 17; radiation wounds, 16; and other etiology, 6). Adipose-derived stromal vascular fraction (SVF) injection was utilized in 11 patients: knee joint osteoarthritis, 7; radiation rectovaginal fistula, 2; rectum radiation wound, 1; and right leg chronic wound (Wegener’s granulomatosis), 1. Fat was harvested by liposuction. Lipoaspirate was centrifuged with 1200g during 3 minutes. Liquid fraction and oil were removed. Coleman type 1 and 3 cannulas of 0.8, 1.0, 1.2, 1.6, and 2.0 mm diameter were used to inject purified fatty tissue. Occasionally sharp needle was used. Digestion with collagenase type II was performed to isolate stromal-vascular cell fraction. Stromal cell sediment was then resuspended in a saline solution and injected with sharp 18- to 27-gauge needles. A small sample was taken out of the obtained cells to characterize final product by means of flow cytometry. Conventional treatment methods were used in all cases before experimental technique was applied. RESULTS For the group of patients with contour deformities, the required result was achieved in all cases. The number of sessions depended on lesion severity and varied from 1 to 8. All cases with combined deformities (cicatrical and irradiated damage) were the most persistent to correct. Complete wound healing was achieved in all patients with chronic radiation wounds. However, among the patients with lower extremities chronic wounds, the final result depended on etiology, ie, complete healing was achieved in 71% cases for diabetic wounds and in 46% of cases for venous congestion wounds. SVF was utilized in cases when fatty tissue injection was impossible to use because of specific local anatomy. Thus, to treat rectum radiation lesions, fat and SVF were injected into the deep planes of rectovaginal septum and rectum mucosa, respectively. Complete healing was achieved for both rectovaginal fistulas and rectum wounds. Injection of SVF into the knee joint has resulted in pain release, improvement of joint mobility, and physical activity of affected extremity. CONCLUSIONS In our opinion, fat grafting should be a method of choice for any contour deformities correction regardless of its severity. Fat injection also turned out to be a very effective tool for stimulating chronic wounds healing. Using the SVF of adipose tissue opens the new opportunities in regenerative surgery.

1116 Use of stromal vascular fraction of adipose tissue in patients with vasculogenic erectile dysfunction: Evaluation of clinical effectiveness and safety (Preliminary results: Phases 1-2, 6 months of follow-up). NCT02472431

1116 Use of stromal vascular fraction of adipose tissue in patients with vasculogenic erectile dysfunction: Evaluation of clinical effectiveness and safety (Preliminary results: Phases 1-2, 6 months of follow-up). NCT02472431

Association of Quadriceps Muscle Fat With Isometric Strength Measurements in Healthy Males Using Chemical Shift Encoding-Based Water-Fat Magnetic Resonance Imaging.

Magnetic resonance–based assessment of quadriceps muscle fat has been proposed as surrogate marker in sarcopenia, osteoarthritis, and neuromuscular disorders. We presently investigated the association of quadriceps muscle fat with isometric strength measurements in healthy males using chemical shift encoding-based water-fat magnetic resonance imaging. Intermuscular adipose tissue fraction and intramuscular proton density fat fraction correlated significantly (P < 0.05) with isometric strength (up to r = −0.83 and −0.87, respectively). Reproducibility of intermuscular adipose tissue fraction and intramuscular proton density fat fraction was 1.5% and 5.7%, respectively.

Elevated autophagy gene expression in adipose tissue of obese humans: A potential non-cell-cycle-dependent function of E2F1

Autophagy genes' expression is upregulated in visceral fat in human obesity, associating with obesity-related cardio-metabolic risk. E2F1 (E2F transcription factor 1) was shown in cancer cells to transcriptionally regulate autophagy. We hypothesize that E2F1 regulates adipocyte autophagy in obesity, associating with endocrine/metabolic dysfunction, thereby, representing non-cell-cycle function of this transcription factor. E2F1 protein (N=69) and mRNA (N=437) were elevated in visceral fat of obese humans, correlating with increased expression of ATG5 (autophagy-related 5), MAP1LC3B/LC3B (microtubule-associated protein 1 light chain 3 β), but not with proliferation/cell-cycle markers. Elevated E2F1 mainly characterized the adipocyte fraction, whereas MKI67 (marker of proliferation Ki-67) was elevated in the stromal-vascular fraction of adipose tissue. In human visceral fat explants, chromatin-immunoprecipitation revealed body mass index (BMI)-correlated increase in E2F1 binding to the promoter of MAP1LC3B, but not to the classical cell cycle E2F1 target, CCND1 (cyclin D1). Clinically, omental fat E2F1 expression correlated with insulin resistance, circulating free-fatty-acids (FFA), and with decreased circulating ADIPOQ/adiponectin, associations attenuated by adjustment for autophagy genes. Overexpression of E2F1 in HEK293 cells enhanced promoter activity of several autophagy genes and autophagic flux, and sensitized to further activation of autophagy by TNF. Conversely, mouse embryonic fibroblast (MEF)-derived adipocytes from e2f1 knockout mice (e2f1−/−) exhibited lower autophagy gene expression and flux, were more insulin sensitive, and secreted more ADIPOQ. Furthermore, e2f1−/− MEF-derived adipocytes, and autophagy-deficient (by Atg7 siRNA) adipocytes were resistant to cytokines-induced decrease in ADIPOQ secretion. Jointly, upregulated E2F1 sensitizes adipose tissue autophagy to inflammatory stimuli, linking visceral obesity to adipose and systemic metabolic-endocrine dysfunction.

Epigenetic Control of Skeletal Development by the Histone Methyltransferase Ezh2

Epigenetic control of gene expression is critical for normal fetal development. However, chromatin-related mechanisms that activate bone-specific programs during osteogenesis have remained underexplored. Therefore, we investigated the expression profiles of a large cohort of epigenetic regulators (>300) during osteogenic differentiation of human mesenchymal cells derived from the stromal vascular fraction of adipose tissue (AMSCs). Molecular analyses establish that the polycomb group protein EZH2 (enhancer of zeste homolog 2) is down-regulated during osteoblastic differentiation of AMSCs. Chemical inhibitor and siRNA knockdown studies show that EZH2, a histone methyltransferase that catalyzes trimethylation of histone 3 lysine 27 (H3K27me3), suppresses osteogenic differentiation. Blocking EZH2 activity promotes osteoblast differentiation and suppresses adipogenic differentiation of AMSCs. High throughput RNA sequence (mRNASeq) analysis reveals that EZH2 inhibition stimulates cell cycle inhibitory proteins and enhances the production of extracellular matrix proteins. Conditional genetic loss of Ezh2 in uncommitted mesenchymal cells (Prrx1-Cre) results in multiple defects in skeletal patterning and bone formation, including shortened forelimbs, craniosynostosis, and clinodactyly. Histological analysis and mRNASeq profiling suggest that these effects are attributable to growth plate abnormalities and premature cranial suture closure because of precocious maturation of osteoblasts. We conclude that the epigenetic activity of EZH2 is required for skeletal patterning and development, but EZH2 expression declines during terminal osteoblast differentiation and matrix production.

Commentary on: Human Adipose Tissue-Derived Stromal/Stem Cells Promote Migration and Early Metastasis of Head and Neck Cancer Xenografts.

Autologous fat grafting for soft tissue reconstruction was first reported by Neuber in 1893 for the correction of facial defects.1 While this technique was largely ignored until the late 1970s, the procedure has now grown exponentially due to its vast degree of applications in soft tissue reconstruction and aesthetic augmentation. Despite its surging popularity, fat graft survival remains highly variable, ranging from 40 to 50 percent graft volume retention.2 While a relatively high degree of graft resorption may be undesirable, the procedure is extremely safe, with few minor complications such as calcification or cyst formation. Much research has been performed to evaluate the variables most highly associated with graft viability, including graft volume, suction pressure, shear stress, and centrifugation. Another major area of investigation to improve graft retention is the application of adipose-derived stromal/stem cells (ASC). ASCs are cells present within the stromal vascular fraction of adipose tissue and serve as progenitor or stem cells with the potential to self-renew or differentiate into multiple cell lineages including adipocytes, osteocytes, chondrocytes, and even cardiomyocytes.3 These cells are believed to strongly influence their local environment through paracrine effects via the expression of growth factors and cytokines, leading to cell growth, differentiation, and angiogenesis. Supplementation of …

Recovery of ulnar nerve defect by autonerve grafting and autotransplantation of stromal vascular fraction of adipose tissue

Recovery of ulnar nerve defect by autonerve grafting and autotransplantation of stromal vascular fraction of adipose tissue

Coxsackie and adenovirus receptor is increased in adipose tissue of obese subjects: a role for adenovirus infection?

The coxsackie and adenovirus receptor (CAR) was originally identified as a common receptor for coxsackie B viruses and type C adenoviruses. The objective was to investigate CAR gene expression in human adipose tissue to explore its associations with adipocyte physiology. This was an ex vivo study in 91 visceral adipose tissue (VAT) and 109 sc adipose tissue (SAT) human samples (61 paired) obtained during elective surgical procedures. Patients were recruited at the Endocrinology Service of the Hospital Universitari Dr Josep Trueta. CAR mRNA was measured in human adipose tissue samples and confirmed at the protein level and in adipose tissue fractions. The effects of inflammatory stimuli on CAR gene expression were also evaluated. In paired samples, CAR was 46-fold higher in VAT vs SAT (P < .0001), being higher also at the protein level (P = .04). CAR was predominantly found in stromal vascular cell fractions (SVFs) in both fat depots. CAR mRNA (P = .006) and protein levels (P = .01) in VAT were significantly increased in obese vs nonobese subjects. In fact, CAR mRNA levels in SAT were positively associated with body mass index (r = 0.26; P = .008) and percentage fat mass (r = 0.28; P = .004). In VAT, MGLL, FSP27, AKAP, omentin, TKT, S14, and FABP contributed independently to CAR mRNA variation after adjusting for age and body mass index. Macrophage-conditioned medium led to increased CAR gene expression in mature adipocytes in vitro. The increased expression of CAR in adipose tissue from obese subjects, mainly in SVFs, suggests that CAR might play a role in adipose tissue dysfunction, given its dual associations with adipogenic and inflammatory genes.

The Stromal Vascular Fraction of Autologous Fat Graft Induces Proliferation of Epithelial Progenitor Cells in Healthy and Cancer-Containing Breast Tissue In Vitro

BACKGROUND: Autologous fat grafting is widely used for managing contour asymmetries in breast reconstruction. Adipose tissue contains a rich population of both multipotent mesenchymal stem cells and vascular progenitor cells (collectively referred to as adipose-derived stem cells, or ASCs).1 When isolated, the cellular fraction of adipose tissue containing ASCs is referred to as stromal vascular fraction (SVF). Despite widespread clinical use, interactions between the SVF of lipoaspirate and breast parenchyma remain poorly understood. Our study investigated the effect of progenitor-rich SVF on the behavior of mammary epithelial progenitor cells derived from two sources: (i) healthy breast tissue and (ii) cancer adjacent breast tissue. METHODS: Healthy breast tissue and abdominal lipoaspirate were obtained from patients undergoing elective reduction mammoplasty and liposuction. Breast tissue from outside the tumor-free margins of mastectomy specimens (termed ‘cancer-adjacent breast tissue’) was obtained from patients undergoing primary free-flap reconstruction. Samples of SVF (from lipoaspirate) and breast parenchymal cells were then isolated using established cell digestion protocols. ASCs within the SVF were characterized using established differentiation, colony-forming unit-fibroblast (CFU-f), and cell surface marker assays.1 Finally, SVF cells were co-cultured with breast parenchymal cells from (i) healthy and (ii) cancer-adjacent sources were co-cultured using a three-dimensional matrix called Matrigel. Control cultures consisted of breast cells from (i) healthy and (ii) cancer-adjacent tissue in the absence of SVF. After 14 days, the total cell numbers and mammary epithelial progenitor cell populations from each culture group were quantified using colony forming cell (CFC) assays. RESULTS: Differentiation, CFU-f, and surface marker assays demonstrated the presence of ASCs in SVF samples. Co-cultures of cancer-adjacent breast parenchymal cells with SVF showed a 9-fold expansion of mammary epithelial progenitor cells (control = 3-fold) compared to a 5.5-fold expansion in co-cultures of healthy breast parenchymal cells (control = 2-fold) with SVF based on CFC assays. CONCLUSIONS: SVF is capable of increasing the proliferation of mammary epithelial progenitor cells in both healthy and cancer-adjacent breast tissue. As a result, this study demonstrates the potential for interaction between the SVF within autologous fat graft and progenitor cells contained within breast parenchymal tissue.

Quest for Circulating Mesenchymal Stem Cells in Man.

Mesenchymal stem cells (MSC) are present in the bone marrow, from where they are thought to migrate via the bloodstream to sites of injury. On the other hand, virtually all tissues contain resident MSC that may contribute to local regenerative and immunomodulatory processes, thereby hypothetically pre-empting the need for recruitment of MSC via the bloodstream. Although there is some indication from animal models, the question remains whether there is solid evidence for the mobilization and migration of MSC in human. In the present study we investigated whether circulating MSC were present in the peripheral blood of healthy individuals and patients with organ injury. We were unable to detect MSC in the blood of healthy individuals by flow cytometry and cell culture techniques. We then analyzed the presence of MSC in the blood of patients with end-stage renal disease (n=10), end-stage liver disease (n=10) and in heart transplant patients with biopsy proven rejection (n=8), by culturing of mononuclear cells under MSC-supporting culture conditions. In none of these patients MSC were identified in the blood. In the stromal vascular fraction of adipose tissue and in liver transplant perfusion fluid we were able to detect MSC, indicating that the methods used enabled the detection of MSC. The conclusion of this study is that MSC are not detectable in the circulation in patients with injured solid organs and during aggressive immune responses.

In vitro assessment of cytotoxicity and labeling efficiency of 99mTc-HMPAO with stromal vascular fraction of adipose tissue.

Noninvasive radionuclide imaging of cells using technetium99m-hexamethylpropyleneamine oxime ((99m)Tc-HMPAO) is a potential diagnostic tool for several applications. Herein we aimed to evaluate the labeling efficiency and cellular toxicity of (99m)Tc-HMPAO with Stromal Vascular Fraction (SVF) of adipose tissue to develop a process tool for theranostic purposes, in particular imaging cardiac stem cell therapy. Ten million cells of SVF were labeled with (99m)Tc-HMPAO complex and excess radiolabel was cleared off through washing in PBS. The labeling efficiency of (99m)Tc-HMPAO was detected in labeled cells and their subsequent supernatant wash using isotope dose calibrator and gamma camera. The cytotoxicity was assessed for the comparative reactive oxygen species (ROS) by H2DCFDDA, apoptotic events by annexin-V and TUNEL assay and mitochondrial potential by JC-1. An encouraging labeling efficiency of 33% was observed with (99m)Tc-HMPAO complex. The radionuclide labeling of SVF demonstrated significant safety profile as evaluated by apoptotic assays. (99m)Tc-HMPAO labeling efficiency of 33% of total SV fraction would produce sufficient radioactive signals that would enable for in vivo tracking of cells by SPECT-CT. The radionuclide did not demonstrate any significant impact on the structural or functional organization of the labeled cells. Our study indicates that SVF can be safely labeled with (99m)Tc-HMPAO without adverse cytotoxic events and for its potential role in imaging cardiac stem cell therapy.

Mesenchymal stem cells: new players in retinopathy therapy.

Retinopathies in human and animal models have shown to occur through loss of pericytes resulting in edema formation, excessive immature retinal angiogenesis, and neuronal apoptosis eventually leading to blindness. In recent years, the concept of regenerating terminally differentiated organs with a cell-based therapy has evolved. The cells used in these approaches are diverse and include tissue-specific endogenous stem cells, endothelial progenitor (EPC), embryonic stem cells, induced pluripotent stem cells (iPSC) and mesenchymal stem cells (MSC). Recently, MSC derived from the stromal fraction of adipose tissue have been shown to possess pluripotent differentiation potential in vitro. These adipose stromal cells (ASC) have been differentiated in a number of laboratories to osteogenic, myogenic, vascular, and adipocytic cell phenotypes. In vivo, ASC have been shown to have functional and phenotypic overlap with pericytes lining microvessels in adipose tissues. Furthermore, these cells either in paracrine mode or physical proximity with endothelial cells, promoted angiogenesis, improved ischemia–reperfusion, protected from myocardial infarction, and were neuroprotective. Owing to the easy isolation procedure and abundant supply, fat-derived ASC are a more preferred source of autologous mesenchymal cells compared to bone marrow MSC. In this review, we present evidence that these readily available ASC from minimally invasive liposuction will facilitate translation of ASC research into patients with retinal diseases in the near future.

Comparison of Markers and Functional Attributes of Human Adipose-Derived Stem Cells and Dedifferentiated Adipocyte Cells from Subcutaneous Fat of an Obese Diabetic Donor

Objective: Adipose tissue is a robust source of adipose-derived stem cells (ADSCs) that may be able to provide secreted factors that promote the ability of wounded tissue to heal. However, adipocytes also have the potential to dedifferentiate in culture to cells with stem cell-like properties that may improve their behavior and functionality for certain applications. Approach: ADSCs are adult mesenchymal stem cells that are cultured from the stromal vascular fraction of adipose tissue. However, adipocytes are capable of dedifferentiating into cells with stem cell properties. In this case study, we compare ADSC and dedifferentiated fat (DFAT) cells from the same patient and fat depot for mesenchymal cell markers, embryonic stem cell markers, ability to differentiate to adipocytes and osteoblasts, senescence and telomerase levels, and ability of conditioned media (CM) to stimulate migration of human dermal fibroblasts (HDFs). Innovation and Conclusions: ADSCs and DFAT cells displayed identical levels of CD90, CD44, CD105, and were CD34- and CD45-negative. They also expressed similar levels of Oct4, BMI1, KLF4, and SALL4. DFAT cells, however, showed higher efficiency in adipogenic and osteogenic capacity. Telomerase levels of DFAT cells were double those of ADSCs, and senescence declined in DFAT cells. CM from both cell types altered the migration of fibroblasts. Despite reports of ADSCs from a number of human depots, there have been no comparisons of the ability of dedifferentiated DFAT cells from the same donor and depot to differentiate or modulate migration of HDFs. Since ADSCs were from an obese diabetic donor, reprogramming of DFAT cells may help improve a patient's cells for regenerative medicine applications.

Impairment of adipose tissue in Prader–Willi syndrome rescued by growth hormone treatment

Prader-Willi syndrome (PWS) results from abnormalities in the genomic imprinting process leading to hypothalamic dysfunction with an alteration of growth hormone (GH) secretion. PWS is associated with early morbid obesity and short stature which can be efficiently improved with GH treatment. Our aims were to highlight adipose tissue structural and functional impairments in children with PWS and to study the modifications of those parameters on GH treatment. Plasma samples and adipose tissue biopsies were obtained from 23 research centers in France coordinated by the reference center for PWS in Toulouse, France. Lean controls (n=33), non-syndromic obese (n=53), untreated (n=26) and GH-treated PWS (n=43) children were enrolled in the study. Adipose tissue biopsies were obtained during scheduled surgeries from 15 lean control, 7 untreated and 8 GH-treated PWS children. Children with PWS displayed higher insulin sensitivity as shown by reduced glycemia, insulinemia and HOMA-IR compared with non-syndromic obese children. In contrast, plasma inflammatory cytokines such as TNF-α, MCP-1 and IL-8 were increased in PWS. Analysis of biopsies compared with control children revealed decreased progenitor cell content in the stromal vascular fraction of adipose tissue and an impairment of lipolytic response to β-adrenergic agonist in PWS adipocytes. Interestingly, both of these alterations in PWS seem to be ameliorated on GH treatment. Herein, we report adipose tissue dysfunctions in children with PWS which may be partially restored by GH treatment.

Regenerative Therapeutic Potential of Adipose Stromal Cells in Early Stage Diabetic Retinopathy

Diabetic retinopathy (DR) is the leading cause of blindness in working-age adults. Early stage DR involves inflammation, vascular leakage, apoptosis of vascular cells and neurodegeneration. In this study, we hypothesized that cells derived from the stromal fraction of adipose tissue (ASC) could therapeutically rescue early stage DR features. Streptozotocin (STZ) induced diabetic athymic nude rats received single intravitreal injection of human ASC into one eye and saline into the other eye. Two months post onset of diabetes, administration of ASC significantly improved “b” wave amplitude (as measured by electroretinogram) within 1–3 weeks of injection compared to saline treated diabetic eyes. Subsequently, retinal histopathological evaluation revealed a significant decrease in vascular leakage and apoptotic cells around the retinal vessels in the diabetic eyes that received ASC compared to the eyes that received saline injection. In addition, molecular analyses have shown down-regulation in inflammatory gene expression in diabetic retina that received ASC compared to eyes that received saline. Interestingly, ASC were found to be localized near retinal vessels at higher densities than seen in age matched non-diabetic retina that received ASC. In vitro, ASC displayed sustained proliferation and decreased apoptosis under hyperglycemic stress. In addition, ASC in co-culture with retinal endothelial cells enhance endothelial survival and collaborate to form vascular networks. Taken together, our findings suggest that ASC are able to rescue the neural retina from hyperglycemia-induced degeneration, resulting in importantly improved visual function. Our pre-clinical studies support the translational development of adipose stem cell-based therapy for DR to address both retinal capillary and neurodegeneration.

Changes in adipose tissue macrophages and T cells during aging.

Adipose tissue historically was believed to be an inert tissue, functioning primarily in the storage of energy and thermal homeostasis. However, recent discoveries point toward a critical role for adipocytes in endocrine function as well as immune regulation. Excess body fat, accumulated through aging and/or a calorie-rich diet, is associated with many chronic metabolic and inflammatory diseases. Within the stromal vascular fraction of adipose tissue, macrophages and T cells accumulate with increasing tissue mass, secreting pro- or anti-inflammatory cytokines. In this review we discuss the current understanding of immune cell function in both diet-induced and age-related obesity. In both models of obesity, the classically activated, pro-inflammatory (M1) subtype takes precedence over the alternatively activated, anti-inflammatory (M2) macrophages, causing tissue necrosis and releasing pro-inflammatory cytokines like interleukin-6. Other distinct adipose tissue macrophage subtypes have been identified by surface marker expression and their functions characterized. Adipose tissue T cell recruitment to adipose tissue is also different between aging- and diet-induced obesity. Under both conditions, T cells exhibit restricted T-cell receptor diversity and produce higher levels of pro-inflammatory signals like interferon-γ and granzyme B relative to young or healthy mice. However, numbers of regulatory T cells are dramatically different between the 2 models of obesity. Taken together, these findings suggest models of age- and diet-induced obesity may be more distinct than previously thought, with many questions yet to be resolved in this multidimensional disease.

Allograft inflammatory factor 1 (AIF-1) is a new human adipokine involved in adipose inflammation in obese women

BackgroundAllograft inflammatory factor 1 (AIF-1) is a putative obesity gene. Our aim was to examine the expression of AIF-1 in human white adipose tissue (WAT) in relation to obesity and metabolic phenotypes in women.MethodsWAT secretion of AIF-1 was determined in subcutaneous adipose tissue pieces in vitro by ELISA from 5 subjects. mRNA expression of AIF-1 was determined by RT-qPCR in the isolated cell fractions of adipose tissue (n = 5-6 per group), in subcutaneous and visceral WAT pieces from non-obese (n = 12) and obese women (n = 23), and in some subcutaneous WAT also before and after weight reduction (n = 10). Finally, adipose AIF-1 mRNA was related to metabolic phenotypes in 96 subjects with a wide range of BMI.ResultsAIF-1 was secreted in a time dependent fashion from WAT. The major source of AIF-1 was WAT resident macrophages. Expression of AIF-1 was similar in visceral and subcutaneous WAT and was two-fold increased in obese women (P < 0.01). AIF-1 mRNA expression levels were normalized after weight reduction (P < 0.01). Expression of AIF-1 was inversely correlated with insulin sensitivity as assessed by insulin tolerance test (KITT), and circulating levels of adiponectin (P = 0.02), and positively correlated with insulin resistance as estimated by HOMA (=0.0042).ConclusionsAIF-1 is a novel adipokine produced mainly by macrophages within human WAT. Its expression is increased in obese women and associates with unfavourable metabolic phenotypes. AIF-1 may play a paracrine role in the regulation of WAT function through cross-talk between macrophages and other cell types within the adipose tissue.