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Human Adipose Tissue (human + adipose_tissue)
Selected AbstractsAdipogenic Differentiation of Human Adipose Tissue,Derived Stem Cells Obtained from Cryopreserved Adipose AspiratesDERMATOLOGIC SURGERY, Issue 7 2010JUNG EUN LEE MS BACKGROUND Although frozen adipose tissue is frequently used for soft tissue augmentation, the viability of frozen fat remains a controversy. The cryopreservation of adipose tissue is important for the future use of adipose-derived stem cells (ASCs) and adipocytes. OBJECTIVE To determine whether optimal cryopreservation techniques with regard to the addition of cryopreservative agents and preservation temperature is essential for the long-term storage of adipose tissue and whether ASCs from cryopreserved adipose aspirates are reliable for use in adipogenic differentiation. MATERIALS AND METHODS Adipose tissue was frozen directly or with cryoprotectant at ,20°C or ,80°C for 1 year. The viability of adipose aspirates and the differentiation of ASCs isolated from adipose tissue were evaluated. RESULTS The viability of adipose aspirates frozen with dimethyl sulfoxide at ,80°C was approximately 87% after 2 months of storage. Moreover, ASCs from adipose tissue stored with cryoprotectant survived successfully for 1 year and differentiated into adipocytes, although ASCs were not detected in the directly frozen adipose tissue. CONCLUSION Adipose tissue cryopreserved with cryoprotectant and stored at optimal temperature might prove to be a reliable source of human ASCs and adipocytes. The authors have indicated no significant interest with commercial supporters. [source] Collagenase-Assisted Fat Dissociation for Autologous Fat TransferDERMATOLOGIC SURGERY, Issue 10 2008DAVID K. MOSCATELLO PHD BACKGROUND The quality of fat for autologous transfer procedures has been a major focus of research in the past few years. The primary goal of these efforts is to improve the viability and longevity of the graft in human subjects. One possible factor in the permanence of theses transplants is the size of the adipose tissue grafts. OBJECTIVE This study evaluated the effects of collagenase digestion on the viability of human adipose tissue. MATERIALS AND METHODS Samples of fat were obtained from subjects undergoing tumescent liposuction. The tissue was digested in a variety of concentrations of collagenase using optimized methods of processing. The digested fat was also subjected to mock injections through small bore needles. RESULTS Eight subjects completed the study. The viability of the fat using the optimized methods of collagenase digestion was consistently higher than 79%. During the mock injection trials, the viability of fat was improved from approximately 17% to 84% by collagenase digestion. CONCLUSIONS Our results show increased viability of human adipose tissue when digested by collagenase. These techniques can be applied to human autologous lipoaugmentation procedures in an effort to improve longevity of the transplanted tissue. [source] DPP-IV inhibition enhances the antilipolytic action of NPY in human adipose tissueDIABETES OBESITY & METABOLISM, Issue 4 2009K. Kos Context:, Dipeptidyl peptidase IV (DPP-IV) inactivates the incretin hormone glucagon-like peptide. It can also affect the orexigenic hormone neuropeptide Y (NPY1,36) which is truncated by DPP-IV to NPY3,36, as a consequence NPY's affinity changes from receptor Y1, which mediates the antilipolytic function of NPY, to other NPY receptors. Little is known whether DPP-IV inhibitors for the treatment of type 2 diabetic (T2DM) patients could influence these pathways. Aims:, To investigate the in vitro effects of NPY with DPP-IV inhibition in isolated abdominal subcutaneous (AbdSc) adipocytes on fat metabolism, and assessment of NPY receptor and DPP-IV expression in adipose tissue (AT). Methods:,Ex vivo human AT was taken from women undergoing elective surgery (body mass index: 27.5 (mean ± s.d.) ± 5 kg/m2, age: 43.7 ± 10 years, n = 36). Isolated AbdSc adipocytes were treated with human recombinant (rh)NPY (1,100 nM) with and without DPP-IV inhibitor (1 M); glycerol release and tissue distribution of DPP-IV, Y1 and Y5 messenger RNA (mRNA) were measured and compared between lean and obese subjects. Results and conclusion:, rhNPY reduced glycerol release, an effect that was further enhanced by co-incubation with a DPP-IV inhibitor [control: 224 (mean ± s.e.) ± 37 ,mol/l; NPY, 100 nM: 161 ± 27 ,mol/l**; NPY 100 nM/DPP-IV inhibitor, 1 M: 127 ± 14 ,mol/l**; **p < 0.01, n = 14]. DPP-IV was expressed in AbdSc AT and omental AT with relative DPP-IV mRNA expression lower in AbdSc AT taken from obese [77 ± 6 signal units (SU)] vs. lean subjects (186 ± 29 SU*, n = 10). Y1 was predominantly expressed in fat and present in all fat depots but higher in obese subjects, particularly the AbdSc AT-depot (obese: 1944 ± 111 SU vs. lean: 711 ± 112 SU**, n = 10). NPY appears to be regulated by AT-derived DPP-IV. DPP-IV inhibitors augment the antilipolytic effect of NPY in AT. Further studies are required to show whether this explains the lack of weight loss in T2DM patients treated with DPP-IV inhibitors. [source] Adipocyte prolactin: regulation of release and putative functionsDIABETES OBESITY & METABOLISM, Issue 4 2007T. Brandebourg Pituitary-derived prolactin (PRL) is a well-known regulator of the lactating mammary gland. However, the recent discovery that human adipose tissue produces PRL as well as expresses the PRL receptor (PRLR) highlights a previously unappreciated action of PRL as a cytokine involved in adipose tissue function. Biologically active PRL is secreted by all adipose tissue depots examined: breast, visceral and subcutaneous. The expression of adipose PRL is regulated by a non-pituitary, alternative superdistal promoter. PRL expression and release increases during early pre-adipocyte differentiation and is stimulated by cyclic AMP activators, including , adrenergic receptor agonists. PRL release from subcutaneous adipose explants is attenuated during obesity, suggesting that adipose PRL production is altered by the metabolic state. Several lines of evidence indicate that PRL suppresses lipid storage as well as the release of adipokines such as adiponectin, interleukin-6 and possibly leptin. PRL has also been implicated in the regulation of adipogenesis. A newly developed PRL-secreting human adipocyte cell line, LS14, should allow comprehensive examination of the regulation and function of adipocyte-derived PRL. Collectively, these studies raise the prospect that PRL affects energy homeostasis through its action as an adipokine and is involved in the manifestation of insulin resistance. [source] Postprandial interstitial insulin concentrations in type 2 diabetes relativesEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 6 2006M. Sandqvist Abstract Background, An endothelial barrier for the insulin transport from the circulation to the target tissues of insulin has previously been suggested to contribute to insulin resistance. The interstitial insulin concentration (I-insulin) and insulin kinetics following a mixed meal have, however, previously not been characterized in human adipose tissue. Subjects and methods, Eight nondiabetic first-degree relatives (FDR) of type 2 diabetes patients were recruited. Their I-insulin was measured by microdialysis after a test meal with or without oral administration of the insulin secretagogue nateglinide (120 mg). In parallel, adipose tissue blood flow and lipolysis were measured by xenon-clearance and microdialysis, respectively. Results, The I-insulin increased after the test meal, and this response was more prominent on the day the subjects received the nateglinide tablet when compared with the day the subjects received the placebo tablet [I-insulin incremental area under the curve (IAUC) nateglinide 7612 ± 3032 vs. Plac 4682 ± 2613 pmol L,1 min; P < 0·05, mean ± SE]. However, the postprandial I-insulinmax/P-insulinmax ratio was similar on the two test days (nateglinide: 213 ± 62 vs. 501 ± 92 pmol L,1, I/P-ratio: 0·38 ± 0·06 and placebo: 159 ± 39 vs. 410 ± 74 pmol L,1, I/P-ratio: 0·36 ± 0·05). There was no difference in time of onset of insulin action in situ, or responsiveness, when comparing placebo and nateglinide. Conclusions, Microdialysis can now be used to measure the I-insulin in human adipose tissue following a mixed meal. The data also showed that the transendothelial delivery of insulin occurs rapidly, supporting the concept that transcapillary insulin transfer is a nonsaturable process in nondiabetic first-degree relatives of type 2 diabetes patients. [source] Aging alters PPAR, in rodent and human adipose tissue by modulating the balance in steroid receptor coactivator-1AGING CELL, Issue 4 2009Stéphanie Miard Summary Age is an important risk factor for the development of metabolic diseases (e.g. obesity, diabetes and atherosclerosis). Yet, little is known about the molecular mechanisms occurring upon aging that affect energy metabolism. Although visceral white adipose tissue (vWAT) is known for its key impact on metabolism, recent studies have indicated it could also be a key regulator of lifespan, suggesting that it can serve as a node for age-associated fat accretion. Here we show that aging triggers changes in the transcriptional milieu of the nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR,) in vWAT, which leads to a modified potential for transactivation of target genes upon ligand treatment. We found that in vWAT of mice, rats and men, aging induced a specific decrease in the expression of steroid receptor coactivator-1 (SRC-1), whose recruitment to PPAR, is associated with improved insulin sensitivity and low adipogenic activity. In contrast, aging and oxidative stress did not impact on PPAR, expression and PPAR, ligand production. Age-induced loss of PPAR,/SRC-1 interactions increased the binding of PPAR, to the promoter of the adipogenic gene aP2. These findings suggest that strategies aimed at increasing SRC-1 expression and recruitment to PPAR, upon aging might help improve age-associated metabolic disorders. [source] Characterization of the Triacylglycerol Crystal Formation in Adipose Tissue During a Vehicle CollisionJOURNAL OF FORENSIC SCIENCES, Issue 4 2007Barbara H. Stuart Ph.D. Abstract:, The unusual appearance of crystalline fat structures was observed during the postmortem examination of a motor vehicle accident victim. The crystal structures were characterized using Fourier transform infrared spectroscopy and x-ray diffractometry. The structures were found to be made of triacylglycerols, a dominant lipid structure found in human adipose tissue, capable of forming various polymorphic structures. The morphology of the crystalline material was found using both techniques to be predominantly the ,, form of triacylglycerols. The accelerated growth of such triacylglycerol morphology has been observed as a result of shear stresses in other studies involving edible fats. As a result of the findings of this study, it is proposed that increased shear forces may be responsible for the formation of the unusual fat structure found in the victim. An understanding of the effect of forces on the structure of body fat in high-impact collisions can potentially assist in verifying a high-velocity impact. [source] ORIGINAL ARTICLE: HLA-G Expression Is Up-Regulated by Progesterone in Mesenchymal Stem CellsAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2009Ekaterina Ivanova-Todorova Problem, Maternal immune response to fetal tissues is modified in such way that it favors the development of pregnancy. Human leukocyte antigen (HLA)-G, progesterone and mesenchymal stem cells (MSCs) have been identified as potent immunomodulatory agents in different experimental systems and the interactions between these three factors are studies in this paper. Method of study, Human MSCs are isolated from human adipose tissue, bone marrow and decidua are cultured in the presence of progesterone and the expression of HLA-G is followed-up at protein and mRNA levels. Results, The MSCs cultured in the presence of progesterone express increased levels of both cell surface and cytoplasmic HLA-G when compared with the control MSCs. Conclusion, Progesterone up-regulates the expression by MSCs of HLA-G which is a major player in maintenance of the immune balance between the mother and the fetus. MSCs are newly detected targets of progesterone with well documented immunomodulatory activity. [source] Human adipose-derived stem cells: isolation, characterization and applications in surgeryANZ JOURNAL OF SURGERY, Issue 4 2009Michelle Locke Abstract The ideal stem cell for use in functional tissue engineering needs to be abundantly available, harvested with minimal morbidity, differentiated reliably down various pathways and able to be transplanted safely and efficaciously. Adult human adipose tissue contains a population of mesenchymal stem cells, termed ,adipose-derived stem cells' (ASC), which seem to fulfil most, if not all, of these criteria. ASC can be harvested readily, safely, and in relative abundance by modern liposuction techniques. They are capable of differentiating into other mesenchymal tissue types, including adipocytes, chondrocytes, myocytes and osteoblasts. They also show angiogenic properties, with recent evidence of a potential role in healing radiotherapy-damaged tissue, possibly due to their secretion of vascular endothelial growth factor. Similarly, they may have a role in healing chronic wounds, and as such are being investigated in phase 1 trials for their ability to aid healing of recurrent Crohn's fistulae. Subsequently they have a wide range of potential clinical uses in all fields of surgery. This article reviews the current and potential clinical applications of ASC in relation to surgery, as well as methods for their isolation, differentiation and molecular characterization. [source] Human exposure to endocrine disrupters: Standardisation of a marker of estrogenic exposure in adipose tissue,APMIS, Issue 3 2001Ana Rivas In many epidemiological studies based on the direct measurement of exposure to organochlorines, the chemicals of concern are determined directly from adipose tissue samples. Although the measurement of all possible organochlorines, their metabolites, isomers and congeners may be desirable, it is expensive and time-consuming and many chemicals with hormonal activity may not yet have been identified. Testing systems are therefore required to screen for estrogenicity and to identify appropriate biomarkers of human exposure. To address this issue, we developed and standardised a method to assess the total estrogenic xenobiotic burden in human adipose tissue. The method extracts and separates the more lipophilic xenoestrogens from ovarian estrogens, with a subsequent bioassay determination of the cumulative effect of the xenoestrogens. It was applied to 400 women, using 200 mg of adipose tissue: 65% of samples showed measurable estrogenicity in the fraction where most non-polar xenoestrogens eluted, and 76% of fractions where ovarian estrogens eluted were positive for estrogenicity. Residues of 16 organochlorine pesticides were determined. No correlation was found between pesticide content and estrogenicity of the samples. The high percentage of positive samples suggests that the method is sensitive enough to be used as a biomarker of human exposure to estrogenic xenobiotics and can be applied in epidemiological studies. [source] | ||||||||||