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BioMed Research International 2020Brown adipose tissue generates heat instead of storing energy. It is important in the regulation of body weight, and individual variation in adaptive thermogenesis can... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Brown adipose tissue generates heat instead of storing energy. It is important in the regulation of body weight, and individual variation in adaptive thermogenesis can be attributed to variations in the amount or activity of BAT.
OBJECTIVE
The objective of this study was to systematically review different articles to assess the prevalence of BAT and its associated factors and relation with obesity and diabetes mellitus.
METHODS
A systematic review and meta-analysis were employed on published research works from different electronic databases using keywords. Cross-sectional studies and a few experimental studies were included for systematic review, and only studies done on human population were used for quantitative analysis. Twenty-two peer-reviewed papers were included in the systematic review, and eight papers were used for the meta-analysis for estimation of pooled prevalence of brown adipose tissue using selection criteria.
RESULTS
The pooled prevalence of brown adipose tissue among adults was 6.97% (95% CI: 6.51-7.43), and it was 7.4% (95% CI 6.51-7.43) after sequential omission of a single study. The heterogeneity in estimating the pooled prevalence among the studies was statistically significant (Cochran test, < 0.001, = 71.2%), and after sequential omission of a single study, it becomes Cochran test, = 0.065, = 49.4%. The brown adipose tissue activity was significantly lower in overweight or obese subjects than in lean subjects.
CONCLUSION
The percentage of adult individuals with brown adipose tissue was high, and its activity was reduced in obese individuals. Although it is reduced in amount, still it presents in obese individuals. So, activation of the brown adipose tissue in adult and older individuals should be a target for the treatment of obesity.
Topics: Adipose Tissue, Brown; Adult; Humans; Obesity; Thermogenesis
PubMed: 32685543
DOI: 10.1155/2020/9106976 -
Frontiers in Endocrinology 2021Obesity is a major risk factor for dysglycemic disorders, including type 2 diabetes (T2D). However, there is wide phenotypic variation in metabolic profiles....
BACKGROUND
Obesity is a major risk factor for dysglycemic disorders, including type 2 diabetes (T2D). However, there is wide phenotypic variation in metabolic profiles. Tissue-specific epigenetic modifications could be partially accountable for the observed phenotypic variability.
SCOPE
The aim of this systematic review was to summarize the available data on epigenetic signatures in human adipose tissue (AT) that characterize overweight or obesity-related insulin resistance (IR) and dysglycemia states and to identify potential underlying mechanisms through the use of unbiased bioinformatics approaches.
METHODS
Original data published in the last decade concerning the comparison of epigenetic marks in human AT of individuals with metabolically unhealthy overweight/obesity (MUHO) versus normal weight individuals or individuals with metabolically healthy overweight/obesity (MHO) was assessed. Furthermore, association of these epigenetic marks with IR/dysglycemic traits, including T2D, was compiled.
RESULTS
We catalogued more than two thousand differentially methylated regions (DMRs; above the cut-off of 5%) in the AT of individuals with MUHO compared to individuals with MHO. These DNA methylation changes were less likely to occur around the promoter regions and were enriched at loci implicated in intracellular signaling (signal transduction mediated by small GTPases, ERK1/2 signaling and intracellular trafficking). We also identified a network of seven transcription factors that may play an important role in targeting DNA methylation changes to specific genes in the AT of subjects with MUHO, contributing to the pathogeny of obesity-related IR/T2D. Furthermore, we found differentially methylated CpG sites at 8 genes that were present in AT and whole blood, suggesting that DMRs in whole blood could be potentially used as accessible biomarkers of MUHO.
CONCLUSIONS
The overall evidence linking epigenetic alterations in key tissues such AT to metabolic complications in human obesity is still very limited, highlighting the need for further studies, particularly those focusing on epigenetic marks other than DNA methylation. Our initial analysis suggests that DNA methylation patterns can potentially discriminate between MUHO from MHO and provide new clues into why some people with obesity are less susceptible to dysglycemia. Identifying AT-specific epigenetic targets could also lead to novel approaches to modify the progression of individuals with obesity towards metabolic disease.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO, identifier CRD42021227237.
Topics: Adipose Tissue; DNA Methylation; Epigenesis, Genetic; Histones; Humans; Metabolic Diseases; Obesity
PubMed: 34290669
DOI: 10.3389/fendo.2021.681649 -
International Journal of Molecular... Apr 2024Adipose tissue is a multifunctional organ that regulates many physiological processes such as energy homeostasis, nutrition, the regulation of insulin sensitivity, body... (Review)
Review
Adipose tissue is a multifunctional organ that regulates many physiological processes such as energy homeostasis, nutrition, the regulation of insulin sensitivity, body temperature, and immune response. In this review, we highlight the relevance of the different mediators that control adipose tissue activity through a systematic review of the main players present in white and brown adipose tissues. Among them, inflammatory mediators secreted by the adipose tissue, such as classical adipokines and more recent ones, elements of the immune system infiltrated into the adipose tissue (certain cell types and interleukins), as well as the role of intestinal microbiota and derived metabolites, have been reviewed. Furthermore, anti-obesity mediators that promote the activation of beige adipose tissue, e.g., myokines, thyroid hormones, amino acids, and both long and micro RNAs, are exhaustively examined. Finally, we also analyze therapeutic strategies based on those mediators that have been described to date. In conclusion, novel regulators of obesity, such as microRNAs or microbiota, are being characterized and are promising tools to treat obesity in the future.
Topics: Humans; Animals; Obesity; Adipose Tissue; Adipokines; MicroRNAs; Gastrointestinal Microbiome; Adipose Tissue, Brown; Adipose Tissue, White; Inflammation Mediators; Energy Metabolism
PubMed: 38731880
DOI: 10.3390/ijms25094659 -
Reumatologia Clinica 2023Systemic inflammatory diseases could act as an unfavorable condition in which epicardial adipose tissue (EAT) becomes harmful to cardiovascular health. The objectives...
BACKGROUND AND AIMS
Systemic inflammatory diseases could act as an unfavorable condition in which epicardial adipose tissue (EAT) becomes harmful to cardiovascular health. The objectives were: (a) to quantitatively compare the presence of EAT between patients with systemic inflammatory diseases and controls; (b) to analyze the association between EAT and subclinical atheromatosis in individuals with systemic inflammatory diseases.
METHODS
Studies that have quantified EAT in a population with systemic inflammatory diseases compared to a control group, or that describe the association between EAT and the presence of subclinical atheromatosis in patients with systemic inflammatory diseases were included. A quantitative analysis was performed for the first objective. This systematic review was performed according to PRISMA guidelines.
RESULTS
Twenty-one studies including 1448 patients with systemic inflammatory diseases, were considered eligible for this study. Patients with systemic inflammatory disease have a higher volume (MD: 10.4cm [1.8-19.1]; p<0.01), higher thickness (MD: 1.0mm [0.8-1.2]; p<0.01), and a statistically non-significant higher area (MD: 3.1cm [1.0-5.2]; p=0.46) of EAT compared to the control group. Most studies reported a significant association between EAT and subclinical atheromatosis in patients with different systemic inflammatory diseases.
CONCLUSION
This study demonstrated that EAT is increased in patients with systemic inflammatory diseases compared with healthy controls, and that EAT measurement is closely correlated with subclinical atherosclerosis in these patients. The causality of this association should be tested in prospective studies.
Topics: Humans; Prospective Studies; Pericardium; Atherosclerosis; Adipose Tissue
PubMed: 37661114
DOI: 10.1016/j.reumae.2022.10.003 -
Journal of Clinical Medicine Dec 2023The use of minimally manipulated adipose tissue (MM-AT) products is gaining increasing interest for the treatment of knee osteoarthritis (OA). MM-AT represents an easy... (Review)
Review
Adipose Tissue-Derived Minimally Manipulated Products versus Platelet-Rich Plasma for the Treatment of Knee Osteoarthritis: A Systematic Review of Clinical Evidence and Meta-Analysis.
The use of minimally manipulated adipose tissue (MM-AT) products is gaining increasing interest for the treatment of knee osteoarthritis (OA). MM-AT represents an easy way to exploit adipose tissue properties, although clinical evidence is still limited, as well as their benefits with respect to more documented orthobiologics like platelet-rich plasma (PRP). A systematic review and meta-analysis were performed to evaluate the safety and efficacy of MM-AT products for knee OA management. The risk of bias of the included studies was evaluated using the Dawns and Black checklist for all the included studies and RoB-2.0 for randomized controlled trials (RCTs). Thirty-three clinical studies were included in the qualitative analysis: 13 prospective case series, 10 retrospective case series, 7 RCTs, 2 retrospective comparative studies, and 1 prospective comparative study. An overall clinical improvement and few minor adverse events were observed. Five RCTs comparing MM-AT and PRP injections were meta-analyzed, showing comparable results. The analysis also highlighted the limits of the literature, with only a few high-level trials and an overall low quality. Even though the current literature is still limited, the available evidence suggests the safety and overall positive results of the intra-articular injections of MM-AT products for knee OA treatment.
PubMed: 38202074
DOI: 10.3390/jcm13010067 -
International Journal of Molecular... Dec 2022Asthma and obesity are considered as highly prevalent diseases with a great impact on public health. Obesity has been demonstrated to be an aggravating factor in the... (Meta-Analysis)
Meta-Analysis Review
Asthma and obesity are considered as highly prevalent diseases with a great impact on public health. Obesity has been demonstrated to be an aggravating factor in the pathogenesis of asthma. Adipose tissue secretes proinflammatory cytokines and mediators, including leptin, which may promote the development and severity of asthma in obese patients. This study is a systematic review and a meta-analysis based on the relationship between leptin and asthma during obesity. MEDLINE, Cochrane, EMBASE and CINAHL databases were used. Data heterogeneity was analyzed using Cochran’s Q and treatment effect with the DerSimonian and Laird method. Random effect analyses were carried out to test data sensitivity. Asymmetry was estimated using Begg’s and Egger’s tests. All studies showed significant differences in leptin levels. The effect of the measures (p < 0.001), data sensitivity (p < 0.05) and data asymmetry were statistically significant, as well as tBegg’s test (p = 0.010) and Egge’s test (p < 0.001). Despite the existing limiting factors, the results of this study support the relevant role of leptin in the pathophysiology of asthma in obese subjects. Nevertheless, further studies are needed to obtain better insight in the relationship between leptin and asthma in obesity.
Topics: Humans; Adipose Tissue; Asthma; Cytokines; Leptin; Obesity
PubMed: 36613991
DOI: 10.3390/ijms24010546 -
Frontiers in Endocrinology 2023We conducted a systematic review and meta-analysis to investigate the effect of exercise training on body composition outcomes in postmenopausal women. (Meta-Analysis)
Meta-Analysis
INTRODUCTION
We conducted a systematic review and meta-analysis to investigate the effect of exercise training on body composition outcomes in postmenopausal women.
METHODS
PubMed, Web of Science, CINAHL, and Medline were searched to identify the randomized controlled trials which evaluated effect of exercise training versus control in postmenopausal women. Standardized mean differences (SMD), weighted mean differences (WMD) and 95% confidence intervals (95% CIs) were calculated using random effects model.
RESULTS
One hundred and one studies involving 5,697 postmenopausal women were included in the meta-analysis. Results indicated that exercise training effectively increased muscle mass/ volume, muscle and fiber cross-sectional area and fat-free mass, and decreased fat mass, body fat percentage, waist circumference and visceral fat. Furthermore, subgroup analyses results revealed that aerobic and combined training had greater beneficial effects on fat mass outcomes, whereas resistance and combined training had greater beneficial effects on muscle mass outcomes.
DISCUSSION
Overall, our results revealed that exercise training is effective for improving body composition in postmenopausal women. To be specific, aerobic training is effective on fat loss, whereas resistance training is effective on muscle gain. However, combination of aerobic and resistance trainings may be considered a viable strategy to improve body composition in postmenopausal women.
SYSTEMATIC REVIEW REGISTRATION
https://www.crd.york.ac.uk/prospero/, identifier CRD42021283425.
Topics: Humans; Female; Postmenopause; Body Composition; Exercise; Intra-Abdominal Fat; Muscles
PubMed: 37388207
DOI: 10.3389/fendo.2023.1183765 -
Stem Cells Translational Medicine Sep 2021Regenerative, cell-based therapy is a promising treatment option for diabetic kidney disease (DKD), which has no cure. To prepare for clinical translation, this... (Meta-Analysis)
Meta-Analysis Review
Regenerative, cell-based therapy is a promising treatment option for diabetic kidney disease (DKD), which has no cure. To prepare for clinical translation, this systematic review and meta-analysis summarized the effect of cell-based interventions in DKD animal models and treatment-related factors modifying outcomes. Electronic databases were searched for original investigations applying cell-based therapy in diabetic animals with kidney endpoints (January 1998-May 2019). Weighted or standardized mean differences were estimated for kidney outcomes and pooled using random-effects models. Subgroup analyses tested treatment-related factor effects for outcomes (creatinine, urea, urine protein, fibrosis, and inflammation). In 40 studies (992 diabetic rodents), therapy included mesenchymal stem/stromal cells (MSC; 61%), umbilical cord/amniotic fluid cells (UC/AF; 15%), non-MSC (15%), and cell-derived products (13%). Tissue sources included bone marrow (BM; 65%), UC/AF (15%), adipose (9%), and others (11%). Cell-based therapy significantly improved kidney function while reducing injury markers (proteinuria, histology, fibrosis, inflammation, apoptosis, epithelial-mesenchymal-transition, oxidative stress). Preconditioning, xenotransplantation, and disease-source approaches were effective. MSC and UC/AF cells had greater effect on kidney function while cell products improved fibrosis. BM and UC/AF tissue sources more effectively improved kidney function and proteinuria vs adipose or other tissues. Cell dose, frequency, and administration route also imparted different benefits. In conclusion, cell-based interventions in diabetic animals improved kidney function and reduced injury with treatment-related factors modifying these effects. These findings may aid in development of optimal repair strategies through selective use of cells/products, tissue sources, and dose administrations to allow for successful adaptation of this novel therapeutic in human DKD.
Topics: Animals; Diabetes Mellitus; Diabetic Nephropathies; Fibrosis; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Umbilical Cord
PubMed: 34106528
DOI: 10.1002/sctm.19-0419 -
Iranian Journal of Public Health Jan 2024Cell aging is associated with changes in telomeres due to DNA damage arising from chronic inflammation in obese patients. The aim of the systematic review and... (Review)
Review
BACKGROUND
Cell aging is associated with changes in telomeres due to DNA damage arising from chronic inflammation in obese patients. The aim of the systematic review and meta-analysis was to find the relationship between obesity and aging or senescence.
METHODS
The systematic review was conducted through PRISMA guideline, beginning with literature search within 2012-2022 in several databases (PubMed, EBSCOHost, Science Direct, Scopus, and Cochrane) followed by screening process using predetermined PICO criteria. Original studies on the topic of obesity and senescence (aging), from preclinical studies to clinical research (cohort or cross-sectional studies) that were published within the last ten years. All studies were appraised using SYRCLE risk of bias tool for preclinical studies and Newcastle-Ottawa Scale (NOS) for cross-sectional and cohort studies. The data extraction on the studies' characteristic and outcome on aging or senescence were followed by quantitative analysis using MetaXL process on prevalence ratio and hazard ratio of obesity to comorbidities and mortality.
RESULTS
Fifteen studies were enrolled. Obesity and white adipose tissue cause increased levels of pro-inflammatory and pro-senescence cytokine and macrophage whilst the aging process lowers metabolism with increased insulin resistance and linked to increased risk of obesity. Obesity occurs in 22% (95% CI 18%-26%) of elderly population with higher prevalence rate in the women population. Obesity is associated with significant increased risk of multimorbidity by 56% (OR = 1.58 [95% CI 1.48-1.96]).
CONCLUSION
The obesity and aging or senescence has reciprocal relationship between each other.
PubMed: 38694856
DOI: 10.18502/ijph.v53i1.14679 -
International Journal of Molecular... Mar 2024Wound healing is an intricate process involving coordinated interactions among inflammatory cells, skin fibroblasts, keratinocytes, and endothelial cells. Successful... (Review)
Review
Wound healing is an intricate process involving coordinated interactions among inflammatory cells, skin fibroblasts, keratinocytes, and endothelial cells. Successful tissue repair hinges on controlled inflammation, angiogenesis, and remodeling facilitated by the exchange of cytokines and growth factors. Comorbid conditions can disrupt this process, leading to significant morbidity and mortality. Stem cell therapy has emerged as a promising strategy for enhancing wound healing, utilizing cells from diverse sources such as endothelial progenitor cells, bone marrow, adipose tissue, dermal, and inducible pluripotent stem cells. In this systematic review, we comprehensively investigated stem cell therapies in chronic wounds, summarizing the clinical, translational, and primary literature. A systematic search across PubMed, Embase, Web of Science, Google Scholar, and Cochrane Library yielded 22,454 articles, reduced to 44 studies after rigorous screening. Notably, adipose tissue-derived mesenchymal stem cells (AD-MSCs) emerged as an optimal choice due to their abundant supply, easy isolation, ex vivo proliferative capacities, and pro-angiogenic factor secretion. AD-MSCs have shown efficacy in various conditions, including peripheral arterial disease, diabetic wounds, hypertensive ulcers, bullous diabeticorum, venous ulcers, and post-Mohs micrographic surgery wounds. Delivery methods varied, encompassing topical application, scaffold incorporation, combination with plasma-rich proteins, and atelocollagen administration. Integration with local wound care practices resulted in reduced pain, shorter healing times, and improved cosmesis. Stem cell transplantation represents a potential therapeutic avenue, as transplanted stem cells not only differentiate into diverse skin cell types but also release essential cytokines and growth factors, fostering increased angiogenesis. This approach holds promise for intractable wounds, particularly chronic lower-leg wounds, and as a post-Mohs micrographic surgery intervention for healing defects through secondary intention. The potential reduction in healthcare costs and enhancement of patient quality of life further underscore the attractiveness of stem cell applications in wound care. This systematic review explores the clinical utilization of stem cells and stem cell products, providing valuable insights into their role as ancillary methods in treating chronic wounds.
Topics: Humans; Endothelial Cells; Quality of Life; Wound Healing; Pluripotent Stem Cells; Intercellular Signaling Peptides and Proteins; Cytokines; Mesenchymal Stem Cell Transplantation
PubMed: 38474251
DOI: 10.3390/ijms25053006