-
ELife Jul 2020Complex interaction between genetics, epigenetics, environment, and nutrition affect the physiological activities of adipose tissues and their dysfunctions, which lead... (Review)
Review
Complex interaction between genetics, epigenetics, environment, and nutrition affect the physiological activities of adipose tissues and their dysfunctions, which lead to several metabolic diseases including obesity or type 2 diabetes. Here, adipogenesis appears to be a process characterized by an intricate network that involves many transcription factors and long noncoding RNAs (lncRNAs) that regulate gene expression. LncRNAs are being investigated to determine their contribution to adipose tissue development and function. LncRNAs possess multiple cellular functions, and they regulate chromatin remodeling, along with transcriptional and post-transcriptional events; in this way, they affect gene expression. New investigations have demonstrated the pivotal role of these molecules in modulating white and brown/beige adipogenic tissue development and activity. This review aims to provide an update on the role of lncRNAs in adipogenesis and adipose tissue function to promote identification of new drug targets for treating obesity and related metabolic diseases.
Topics: Adipogenesis; Adipose Tissue; Adipose Tissue, Brown; Adipose Tissue, White; Chromatin Assembly and Disassembly; Gene Regulatory Networks; Humans; RNA, Long Noncoding; Transcription Factors
PubMed: 32730204
DOI: 10.7554/eLife.59053 -
Comprehensive Physiology Sep 2017The renin angiotensin system (RAS) is a major regulator of blood pressure, fluid, and electrolyte homeostasis. RAS precursor angiotensinogen (Agt) is cleaved into... (Review)
Review
The renin angiotensin system (RAS) is a major regulator of blood pressure, fluid, and electrolyte homeostasis. RAS precursor angiotensinogen (Agt) is cleaved into angiotensin I (Ang I) and II (Ang II) by renin and angiotensin converting enzyme (ACE), respectively. Major effects of Ang II, the main bioactive peptide of this system, is mediated by G protein coupled receptors, Angiotensin Type 1 (AGTR1, AT1R) and Type 2 (AGTR2, AT2R) receptors. Further, the discovery of additional RAS peptides such as Ang 1-7 generated by the action of another enzyme ACE2 identified novel functions of this complex system. In addition to the systemic RAS, several local RAS exist in organs such as the brain, kidney, pancreas, and adipose tissue. The expression and regulation of various components of RAS in adipose tissue prompted extensive research into the role of adipose RAS in metabolic diseases. Indeed, animal studies have shown that adipose-derived Agt contributes to circulating RAS, kidney, and blood pressure regulation. Further, mice overexpressing Agt have high blood pressure and increased adiposity characterized by inflammation, adipocyte hypertrophy, and insulin resistance, which can be reversed at least in part by RAS inhibition. These findings highlight the importance of this system in energy homeostasis, especially in the context of obesity. This overview article discusses the depot-specific functions of adipose RAS, genetic and pharmacological manipulations of RAS, and its applications to adipogenesis, thermogenesis, and overall energy homeostasis. © 2017 American Physiological Society. Compr Physiol 7:1137-1150, 2017.
Topics: Adipose Tissue, Brown; Adipose Tissue, White; Animals; Blood Pressure; Energy Metabolism; Homeostasis; Humans; Renin-Angiotensin System
PubMed: 28915321
DOI: 10.1002/cphy.c160031 -
International Journal of Molecular... Aug 2021Brown adipose tissue (BAT), a uniquely thermogenic tissue that plays an important role in metabolism and energy expenditure, has recently become a revived target in the... (Review)
Review
Brown adipose tissue (BAT), a uniquely thermogenic tissue that plays an important role in metabolism and energy expenditure, has recently become a revived target in the fight against metabolic diseases, such as obesity, diabetes, and non-alcoholic fatty liver disease (NAFLD). Different from white adipose tissue (WAT), the brown adipocytes have distinctive features including multilocular lipid droplets, a large number of mitochondria, and a high expression of uncoupling protein-1 (UCP-1), as well as abundant capillarity. These histologic characteristics provide an opportunity to differentiate BAT from WAT using imaging modalities, such as PET/CT, SPECT/CT, MRI, NIRF and Ultrasound. However, most of the reported imaging methods were BAT activation dependent, and the imaging signals could be affected by many factors, including environmental temperatures and the states of the sympathetic nervous system. Accurate BAT mass detection methods that are independent of temperature and hormone levels have the capacity to track the development and changes of BAT throughout the lifetime of mammals, and such methods could be very useful for the investigation of potential BAT-related therapies. In this review, we focus on molecular imaging modalities that can detect and quantify BAT mass. In addition, their detection mechanism and limitations will be discussed as well.
Topics: Adipose Tissue, Brown; Adipose Tissue, White; Animals; Humans; Metabolic Diseases; Molecular Imaging
PubMed: 34502347
DOI: 10.3390/ijms22179436 -
Biorheology 2020Obesity-induced chronic inflammation and fibrosis in adipose tissue contributes to the progression of type 2 diabetes mellitus (DM). While fibrosis is known to induce...
BACKGROUND
Obesity-induced chronic inflammation and fibrosis in adipose tissue contributes to the progression of type 2 diabetes mellitus (DM). While fibrosis is known to induce mechanical stiffening of numerous tissue types, it is unknown whether DM is associated with alterations in adipose tissue mechanical properties.
OBJECTIVE
The purpose of this study was to investigate whether DM is associated with differences in bulk viscoelastic properties of adipose tissue from diabetic (DM) and non-diabetic (NDM) obese subjects.
METHODS
Bulk shear rheology was performed on visceral (VAT) and subcutaneous (SAT) adipose tissue, collected from obese subjects undergoing elective bariatric surgery. Rheology was also performed on the remaining extracellular matrix (ECM) from decellularized VAT (VAT ECM). Linear mixed models were used to assess whether correlations existed between adipose tissue mechanical properties and DM status, sex, age, and body mass index (BMI).
RESULTS
DM was not associated with significant differences in adipose tissue viscoelastic properties for any of the tissue types investigated. Tissue type dependent differences were however detected, with VAT having significantly lower shear storage and loss moduli than SAT and VAT ECM independent of DM status.
CONCLUSION
Although DM is typically associated with adipose tissue fibrosis, it is not associated with differences in macroscopic adipose tissue mechanical properties.
Topics: Adipose Tissue; Diabetes Mellitus, Type 2; Female; Humans; Intra-Abdominal Fat; Male; Obesity; Subcutaneous Fat
PubMed: 32083565
DOI: 10.3233/BIR-190234 -
Acta Pharmacologica Sinica Feb 2022The excess deposition of underlying extracellular matrix (ECM) in adipose tissue is defined as adipose tissue fibrosis that is a major contributor to metabolic disorder...
The excess deposition of underlying extracellular matrix (ECM) in adipose tissue is defined as adipose tissue fibrosis that is a major contributor to metabolic disorder such as obesity and type 2 diabetes. Anti-fibrosis therapy has received much attention in the treatment of metabolic disorders. Orosomucoid (ORM) is an acute-phase protein mainly produced by liver, which is also an adipokine. In this study, we investigated the effects of ORM on adipose tissue fibrosis and the potential mechanisms. We showed that ORM1-deficient mice exhibited an obese phenotype, manifested by excessive collagen deposition in adipose tissues and elevated expression of ECM regulators such as metalloproteinases (MMP-2, MMP-13, MMP-14) and tissue inhibitors of metalloproteinases (TIMP-1, TIMP-2, TIMP-3). Administration of exogenous ORM (50 mg· kg· d, ip) for 7 consecutive days in high-fat diet (HFD)-fed mice and leptin receptor (LepR)-deficient db/db mice attenuated these abnormal expressions. Meanwhile, ORM administration stimulated AMP-activated protein kinase (AMPK) phosphorylation and decreased transforming growth factor-β1 (TGF-β1) level in adipose tissues of the mice. In TGF-β1-treated 3T3-L1 fibroblasts, ORM (10 μg/mL) improved the impaired expression profiles of fibrosis-related genes, whereas a selective AMPK inhibitor dorsomorphin (1 μmol/mL) abolished these effects. Together, our results suggest that ORM exerts a direct anti-fibrosis effect in adipose tissue via AMPK activation. ORM is expected to become a novel target for the treatment of adipose tissue fibrosis.
Topics: 3T3 Cells; AMP-Activated Protein Kinases; Adipokines; Adipose Tissue; Animals; Blotting, Western; Diet, High-Fat; Fibrosis; Magnetic Resonance Imaging; Male; Mice; Mice, Inbred C57BL; Orosomucoid; Signal Transduction
PubMed: 33875797
DOI: 10.1038/s41401-021-00666-9 -
Medecine Sciences : M/S Apr 2014Adipose tissue is found in close proximity whith many invasive cancers. In breast cancer, early local tumour invasion results in close interactions of cancer cells with... (Review)
Review
Adipose tissue is found in close proximity whith many invasive cancers. In breast cancer, early local tumour invasion results in close interactions of cancer cells with fully differentiated adipocytes. Aside from their energy-storing function, mature adipocytes are also active endocrine cells prone to influence tumour behaviour through heterotypic signaling processes. After a short description of anatomical depots specificities of adipose tissue, we describe the phenotypic changes induced by tumor secretion in tumour-surrounding adipocytes. These cells (that we named CAA for cancer-associated adipocytes) by their ability to secrete pro-inflammatory cytokines, extra-cellular matrix proteins and proteases involved in its remodeling, as well as to release free fatty acid, stimulate tumor proliferation, invasiveness and drug resistance. These results support the concept that adipocytes participate in a deleterious crosstalk with cancer cells to support tumour progression, that might be amplified in obesity conditions and explain the poor prognosis of cancers observed in this subset of patients.
Topics: Adipocytes; Adipose Tissue; Humans; Neoplasms; Risk Factors; Tumor Microenvironment
PubMed: 24801034
DOI: 10.1051/medsci/20143004013 -
Annals of the Royal College of Surgeons... Apr 2021Soft tissue reconstruction remains a continuing challenge for plastic and reconstructive surgeons. Standard methods of reconstruction such as local tissue transfer and... (Review)
Review
Soft tissue reconstruction remains a continuing challenge for plastic and reconstructive surgeons. Standard methods of reconstruction such as local tissue transfer and free autologous tissue transfer are successful in addressing soft tissue cover, yet they do not come without the additional morbidity of donor sites. Autologous fat transfer has been used in reconstruction of soft tissue defects in different branches of plastic surgery, specifically breast and facial defect reconstruction, while further maintaining a role in body contouring procedures. Current autologous fat transfer techniques come with the drawbacks of donor-site morbidity and, more significantly, resorption of large amounts of fat. Advancement in tissue engineering has led to the use of engineered adipose tissue structures based on adipose-derived stem cells. This enables a mechanically similar reconstruct that is abundantly available. Cosmetic and mechanical similarity with native tissue is the main clinical goal for engineered adipose tissue. Development of novel techniques in the availability of natural tissue is an exciting prospect; however, it is important to investigate the potential of cell sources and culture strategies for clinical applications. We review these techniques and their applications in plastic surgery.
Topics: Adipose Tissue; Humans; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Plastic Surgery Procedures; Tissue Engineering
PubMed: 33682428
DOI: 10.1308/rcsann.2020.7031 -
Obesity Research & Clinical Practice 2023To determine the association between both visceral fat quantity and adipose tissue dysfunction, and major bleeding in patients with established cardiovascular disease.
OBJECTIVES
To determine the association between both visceral fat quantity and adipose tissue dysfunction, and major bleeding in patients with established cardiovascular disease.
METHODS
Patients from the Second Manifestations of ARTerial disease study with established cardiovascular disease were included. Visceral fat was measured using ultrasound and adipose tissue dysfunction was depicted using metabolic syndrome criteria (revised National Cholesterol Education Program). Cox regression models were fitted to study the relation with major bleeding defined as Bleeding Academic Research Consortium (BARC) type 3 or 5, or International Society on Thrombosis and Haemostasis (ISTH) major bleeding. Sensitivity analyses were performed using C-reactive protein levels to reflect adipose tissue dysfunction.
RESULTS
In 6927 patients during a median follow up of 9.2 years, a total of 237 BARC type 3 or 5 bleedings and 224 ISTH major bleedings were observed. Visceral fat quantity was not related to major bleeding (HR 1.01, 95%CI 0.88-1.16 for BARC type 3 or 5 bleeding and HR 1.00, 95%CI 0.87-1.15 for ISTH major bleeding), nor was metabolic syndrome (HR 0.97, 95%CI 0.75-1.26 for BARC type 3 or 5 bleeding and HR 0.98, 95%CI 0.75-1.28 for ISTH major bleeding). Sensitivity analyses using C-reactive protein levels showed similar results. No effect modification was observed by sex, antithrombotic therapy, presence of metabolic syndrome or diabetes.
CONCLUSION
In patients with cardiovascular disease, no association was found between visceral fat quantity measured with ultrasound or measures of adipose tissue dysfunction and the risk of major bleeding, irrespective of antithrombotic agent use.
Topics: Humans; Cardiovascular Diseases; Intra-Abdominal Fat; Metabolic Syndrome; C-Reactive Protein; Risk Factors; Hemorrhage; Adipose Tissue
PubMed: 36464615
DOI: 10.1016/j.orcp.2022.11.003 -
International Journal of Molecular... May 2023Adipose tissue (AT) is composed of a heterogeneous population which comprises both progenitor and differentiated cells. This heterogeneity allows a variety of roles for...
Adipose tissue (AT) is composed of a heterogeneous population which comprises both progenitor and differentiated cells. This heterogeneity allows a variety of roles for the AT, including regenerative functions. In fact, autologous AT is commonly used to repair soft tissue defects, and its cryopreservation could be a useful strategy to reduce the patient discomfort caused by multiple harvesting procedures. Our work aimed to characterize the cryopreserved AT and to validate its storage for up to three years for clinical applications. AT components (stromal vascular fraction-SVF and mature adipocytes) were isolated in fresh and cryopreserved samples using enzymatic digestion, and cell viability was assessed by immunofluorescence (IF) staining. Live, apoptotic and necrotic cells were quantified using cytometry by evaluating phosphatidylserine binding to fluorescent-labeled Annexin V. A multiparametric cytometry was also used to measure adipogenic (CD34+CD90+CD31-CD45-) and endothelial (CD34+CD31+CD45-) precursors and endothelial mature cells (CD34-CD31+CD45-). The maintenance of adipogenic abilities was evaluated using in vitro differentiation of SVF cultures and fluorescent lipid staining. We demonstrated that AT that is cryopreserved for up to three years maintains its differentiation potential and cellular composition. Given our results, a clinical study was started, and two patients had successful transplants without any complications using autologous cryopreserved AT.
Topics: Humans; Transplantation, Autologous; Adipose Tissue; Adipocytes; Cell Differentiation; Subcutaneous Fat; Stromal Cells; Cells, Cultured
PubMed: 37175896
DOI: 10.3390/ijms24098190 -
Circulation Journal : Official Journal... Jun 2024
Topics: Humans; Adipose Tissue; Pericardium; Ventricular Premature Complexes; Epicardial Adipose Tissue
PubMed: 38092412
DOI: 10.1253/circj.CJ-23-0825