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International Journal of Molecular... May 2019Obesity is a critical risk factor for the development of type 2 diabetes (T2D), and its prevalence is rising worldwide. White adipose tissue (WAT) has a crucial role in... (Review)
Review
Obesity is a critical risk factor for the development of type 2 diabetes (T2D), and its prevalence is rising worldwide. White adipose tissue (WAT) has a crucial role in regulating systemic energy homeostasis. Adipose tissue expands by a combination of an increase in adipocyte size (hypertrophy) and number (hyperplasia). The recruitment and differentiation of adipose precursor cells in the subcutaneous adipose tissue (SAT), rather than merely inflating the cells, would be protective from the obesity-associated metabolic complications. In metabolically unhealthy obesity, the storage capacity of SAT, the largest WAT depot, is limited, and further caloric overload leads to the fat accumulation in ectopic tissues (e.g., liver, skeletal muscle, and heart) and in the visceral adipose depots, an event commonly defined as "lipotoxicity." Excessive ectopic lipid accumulation leads to local inflammation and insulin resistance (IR). Indeed, overnutrition triggers uncontrolled inflammatory responses in WAT, leading to chronic low-grade inflammation, therefore fostering the progression of IR. This review summarizes the current knowledge on WAT dysfunction in obesity and its associated metabolic abnormalities, such as IR. A better understanding of the mechanisms regulating adipose tissue expansion in obesity is required for the development of future therapeutic approaches in obesity-associated metabolic complications.
Topics: Adipogenesis; Adipose Tissue; Animals; Diabetes Mellitus, Type 2; Humans; Inflammation; Insulin Resistance; Obesity; Subcutaneous Fat
PubMed: 31085992
DOI: 10.3390/ijms20092358 -
Molecular and Cellular Endocrinology Feb 2015The NIH has recently highlighted the importance of sexual dimorphisms and has mandated inclusion of both sexes in clinical trials and basic research. In this review we... (Review)
Review
The NIH has recently highlighted the importance of sexual dimorphisms and has mandated inclusion of both sexes in clinical trials and basic research. In this review we highlight new and novel ways sex hormones influence body adiposity and the metabolic syndrome. Understanding how and why metabolic processes differ by sex will enable clinicians to target and personalize therapies based on gender. Adipose tissue function and deposition differ by sex. Females differ with respect to distribution of adipose tissues, males tend to accrue more visceral fat, leading to the classic android body shape which has been highly correlated to increased cardiovascular risk; whereas females accrue more fat in the subcutaneous depot prior to menopause, a feature which affords protection from the negative consequences associated with obesity and the metabolic syndrome. After menopause, fat deposition and accrual shift to favor the visceral depot. This shift is accompanied by a parallel increase in metabolic risk reminiscent to that seen in men. A full understanding of the physiology behind why, and by what mechanisms, adipose tissues accumulate in specific depots and how these depots differ metabolically by sex is important in efforts of prevention of obesity and chronic disease. Estrogens, directly or through activation of their receptors on adipocytes and in adipose tissues, facilitate adipose tissue deposition and function. Evidence suggests that estrogens augment the sympathetic tone differentially to the adipose tissue depots favoring lipid accumulation in the subcutaneous depot in women and visceral fat deposition in men. At the level of adipocyte function, estrogens and their receptors influence the expandability of fat cells enhancing the expandability in the subcutaneous depot and inhibiting it in the visceral depot. Sex hormones clearly influence adipose tissue function and deposition, determining how to capture and utilize their function in a time of caloric surfeit, requires more information. The key will be harnessing the beneficial effects of sex hormones in such a way as to provide 'healthy' adiposity.
Topics: Adiposity; Animals; Estrogen Receptor alpha; Estrogens; Female; Humans; Intra-Abdominal Fat; Male; Obesity; Organ Specificity; Risk Factors; Sex Characteristics; Subcutaneous Fat
PubMed: 25578600
DOI: 10.1016/j.mce.2014.11.029 -
Nature Communications Jun 2022For any given level of overall adiposity, individuals vary considerably in fat distribution. The inherited basis of fat distribution in the general population is not...
For any given level of overall adiposity, individuals vary considerably in fat distribution. The inherited basis of fat distribution in the general population is not fully understood. Here, we study up to 38,965 UK Biobank participants with MRI-derived visceral (VAT), abdominal subcutaneous (ASAT), and gluteofemoral (GFAT) adipose tissue volumes. Because these fat depot volumes are highly correlated with BMI, we additionally study six local adiposity traits: VAT adjusted for BMI and height (VATadj), ASATadj, GFATadj, VAT/ASAT, VAT/GFAT, and ASAT/GFAT. We identify 250 independent common variants (39 newly-identified) associated with at least one trait, with many associations more pronounced in female participants. Rare variant association studies extend prior evidence for PDE3B as an important modulator of fat distribution. Local adiposity traits (1) highlight depot-specific genetic architecture and (2) enable construction of depot-specific polygenic scores that have divergent associations with type 2 diabetes and coronary artery disease. These results - using MRI-derived, BMI-independent measures of local adiposity - confirm fat distribution as a highly heritable trait with important implications for cardiometabolic health outcomes.
Topics: Adipose Tissue; Adiposity; Body Mass Index; Diabetes Mellitus, Type 2; Female; Humans; Intra-Abdominal Fat; Obesity; Subcutaneous Fat
PubMed: 35773277
DOI: 10.1038/s41467-022-30931-2 -
Plastic and Reconstructive Surgery Oct 2015Interest in and acceptance of autologous fat grafting for use in contour abnormalities, breast reconstruction, and cosmetic procedures have increased. However, there are... (Review)
Review
BACKGROUND
Interest in and acceptance of autologous fat grafting for use in contour abnormalities, breast reconstruction, and cosmetic procedures have increased. However, there are many procedural variations that alter the effectiveness of the procedure and may account for the unpredictable resorption rates observed.
METHODS
The authors highlighted studies investigating the effects of harvesting procedures, processing techniques, and reinjection methods on the survival of fat grafts. This review focused on the impact different techniques have on outcomes observed in the following: in vitro analyses, in vivo animal experiments, and human studies.
RESULTS
This systemic review revealed the current state of the literature. There was no significant difference in the outcomes of grafted fat obtained from different donor sites, different donor-site preparations, harvest technique, fat harvesting cannula size, or centrifugation speed, when tumescent solution was used. Gauze rolling was found to enhance the volume of grafted fat, and no significant difference in retention was observed following centrifugation, filtration, or sedimentation in animal experiments. In contrast, clinical studies in patients found more favorable outcomes with fat processed by centrifugation compared with sedimentation. In addition, higher retention was observed with slower reinjection speed and when introduced into less mobile areas.
CONCLUSIONS
There has been a substantial increase in research interest to identify methodologies for optimizing fat graft survival. Despite some differences in harvest and implantation technique in the laboratory, these findings have not translated into a universal protocol for fat grafting. Therefore, additional human studies are necessary to aid in the development of a universal protocol for clinical practice.
Topics: Humans; Lipectomy; Subcutaneous Fat; Tissue and Organ Harvesting; Transplantation, Autologous
PubMed: 26086386
DOI: 10.1097/PRS.0000000000001590 -
Cell Metabolism Mar 2022In mammals, white adipose tissues are largely divided into visceral epididymal adipose tissue (EAT) and subcutaneous inguinal adipose tissue (IAT) with distinct...
In mammals, white adipose tissues are largely divided into visceral epididymal adipose tissue (EAT) and subcutaneous inguinal adipose tissue (IAT) with distinct metabolic properties. Although emerging evidence suggests that subpopulations of adipose stem cells (ASCs) would be important to explain fat depot differences, ASCs of two fat depots have not been comparatively investigated. Here, we characterized heterogeneous ASCs and examined the effects of intrinsic and tissue micro-environmental factors on distinct ASC features. We demonstrated that ASC subpopulations in EAT and IAT exhibited different molecular features with three adipogenic stages. ASC transplantation experiments revealed that intrinsic ASC features primarily determined their adipogenic potential. Upon obesogenic stimuli, EAT-specific SDC1 ASCs promoted fibrotic remodeling, whereas IAT-specific CXCL14 ASCs suppressed macrophage infiltration. Moreover, IAT-specific BST2 ASCs exhibited a high potential to become beige adipocytes. Collectively, our data broaden the understanding of ASCs with new insights into the origin of white fat depot differences.
Topics: Adipocytes; Adipogenesis; Adipose Tissue; Animals; Mammals; Stem Cells; Subcutaneous Fat
PubMed: 35021043
DOI: 10.1016/j.cmet.2021.11.014 -
Nature Sep 2022Adipose tissues communicate with the central nervous system to maintain whole-body energy homeostasis. The mainstream view is that circulating hormones secreted by the...
Adipose tissues communicate with the central nervous system to maintain whole-body energy homeostasis. The mainstream view is that circulating hormones secreted by the fat convey the metabolic state to the brain, which integrates peripheral information and regulates adipocyte function through noradrenergic sympathetic output. Moreover, somatosensory neurons of the dorsal root ganglia innervate adipose tissue. However, the lack of genetic tools to selectively target these neurons has limited understanding of their physiological importance. Here we developed viral, genetic and imaging strategies to manipulate sensory nerves in an organ-specific manner in mice. This enabled us to visualize the entire axonal projection of dorsal root ganglia from the soma to subcutaneous adipocytes, establishing the anatomical underpinnings of adipose sensory innervation. Functionally, selective sensory ablation in adipose tissue enhanced the lipogenic and thermogenetic transcriptional programs, resulting in an enlarged fat pad, enrichment of beige adipocytes and elevated body temperature under thermoneutral conditions. The sensory-ablation-induced phenotypes required intact sympathetic function. We postulate that beige-fat-innervating sensory neurons modulate adipocyte function by acting as a brake on the sympathetic system. These results reveal an important role of the innervation by dorsal root ganglia of adipose tissues, and could enable future studies to examine the role of sensory innervation of disparate interoceptive systems.
Topics: Adipose Tissue; Adipose Tissue, Beige; Animals; Axons; Energy Metabolism; Ganglia, Spinal; Homeostasis; Hormones; Mice; Organ Specificity; Sensory Receptor Cells; Subcutaneous Fat; Sympathetic Nervous System; Thermogenesis
PubMed: 36045288
DOI: 10.1038/s41586-022-05137-7 -
Dermatology Online Journal Nov 2020Subcutaneous fat necrosis of the newborn is a rare lobular panniculitis. It is characteristic of term or post-term neonates with a history of perinatal compromise or...
Subcutaneous fat necrosis of the newborn is a rare lobular panniculitis. It is characteristic of term or post-term neonates with a history of perinatal compromise or maternal gestational pathology. The cutaneous manifestations consist of erythematous and indurated subcutaneous plaques and nodules located over the dorsal region and the shoulders. Diagnosis is clinical and pathological. Histopathological findings include lobular panniculitis with a lymphohistiocytic inflammatory infiltrate with few neutrophils, fatty necrosis, deposition of radial needle-shaped crystals in the adipocytes, and possible calcification and hemorrhage. The cutaneous ultrasound shows hyperechoic and avascular subcutaneous cellular tissue and acoustic shadows may appear corresponding to calcifications. The clinical differential diagnosis includes sclerema neonatorum and post-corticosteroid panniculitis. Histologically crystal-forming panniculitis conditions are in the differential diagnosis. The disease is usually self-limited but complications such as hypercalcemia, hypoglycemia, hypertriglyceridemia, thrombocytopenia, and anemia may occur. Complications should be ruled out and treated at diagnosis and during follow-up. The most important complication is hypercalcemia.La necrosis grasa subcutánea neonatal es una paniculitis lobulillar infrecuente. Es característica de neonatos a término o postérmino con antecedentes de sufrimiento perinatal o patología gestacional materna. Las manifestaciones cutáneas consisten en placas y nódulos subcutáneos eritematosos e indurados localizados preferentemente en la región dorsal y los hombros. El diagnóstico es clínicopatológico. Los hallazgos histopatológicos comprenden una paniculitis lobulillar con un infiltrado inflamatorio linfohistiocitario con escasos neutrófilos, necrosis grasa, depósito de cristales radiados en los adipocitos y posibles focos de calcificación y hemorragia. En la ecografía cutánea se observa hiperecogenicidad y avascularización del tejido celular subcutáneo y pueden aparecer sombras acústicas posteriores que se correspondencon calcificaciones. El diagnóstico diferencial clínico se debe realizar con el escleredema neonatorum y la paniculitis postesteroidea, e histológicamente con las paniculitis con formación de cristales. La enfermedad suele ser autolimitada pero pueden aparecer complicaciones como la hipercalcemia, la hipoglucemia, la hipertrigliceridemia, latrombocitopenia y la anemia. Las complicaciones deben ser descartadas y tratadas en el diagnóstico y durante el seguimiento. La complicación másimportante es la hipercalcemia.
Topics: Back; Female; Humans; Infant, Newborn; Neck; Subcutaneous Fat; Ultrasonography
PubMed: 33342185
DOI: No ID Found -
International Wound Journal Apr 2023Skin grafting is an important method of wound repair and reconstruction. Skin grafting can be classified using multiple classification criteria. We often perform...
Skin grafting is an important method of wound repair and reconstruction. Skin grafting can be classified using multiple classification criteria. We often perform full-thickness skin grafting (FTSG) for small wound areas; however, the traditional FTSG technique frequently causes postoperative scar depression at the donor site, especially in the abdomen. This study aimed to determine whether preserving the subcutaneous fat when performing FTSG can improve donor site prognosis. We reviewed 25 patients who underwent autologous FTSG in the last 3 years. Among them, subcutaneous fat was preserved in 11 patients (experimental group), whereas it was not preserved in 14 patients (control group). Using a 3D camera and the Patient and Observer Scar Assessment Scale (POSAS), we evaluated the donor site postoperatively. According to POSAS, vascularization was significantly more severe in the experimental group. The Antera 3D camera revealed more severe scar depression at the donor site in the control group. The processing time for graft take, subcutaneous fat trimming and donor site closure was less in the experimental group than in the control group. Preserving subcutaneous fat at the donor site improved patient outcomes by reducing donor site depression after FTSG.
Topics: Humans; Cicatrix; Skin; Skin Transplantation; Subcutaneous Fat; Wound Healing
PubMed: 36330586
DOI: 10.1111/iwj.13975 -
The American Journal of Clinical... Sep 2022Race and sex differences in adolescents' body fat are demonstrated in cross-sectional cohorts, yet a longitudinal design would better identify patterns of fat...
BACKGROUND
Race and sex differences in adolescents' body fat are demonstrated in cross-sectional cohorts, yet a longitudinal design would better identify patterns of fat distribution over time.
OBJECTIVES
The aim was to examine race and sex differences in adiposity between black and white adolescents over 2 y.
METHODS
A cohort of adolescents aged 10-16 y (38% black; 52% girls; 15% overweight, 34% with obesity) underwent body composition measurements at baseline (n = 309) and 2 y later (n = 236), using DXA to quantify whole-body fat mass (FM) and MRI for abdominal subcutaneous (SAT) and visceral adipose tissue (VAT) volumes. General linear models were used to examine race and sex differences in log-transformed FM, SAT, and VAT, adjusting for age, sexual maturation, extended BMI percentile, and race-by-sex interaction. SAT and VAT models in addition controlled for baseline FM and change in FM (for change models).
RESULTS
Mean (95% CI) baseline FM (kg) was higher among white [18.5 (17.9, 19.2) than among black adolescents [17.4 (16.6, 18.2), P = 0.03] and girls [19.5 (18.8, 20.3) than boys [16.5 (15.8, 17.2), P < 0.0001]. Mean (95% CI) baseline SAT (L) was higher among girls [4.4 (4.2, 4.6)] than among boys [3.9 (3.7, 4.1), P < 0.0001]. Mean (95% CI) baseline VAT (L) was higher among white [0.5 (0.5, 0.6)] than among black [0.3 (0.3, 0.4)] adolescents (P < 0.0001) and boys [0.5 (0.4, 0.5)] than girls [0.4 (0.4, 0.4), P = 0.04]. Over 2 y mean (95% CI) FM change (kg) was higher among white [3.7 (2.9, 4.5)] than among black adolescents [2.3 (1.3, 3.3), P = 0.04] and girls [4.0 (3.0, 4.9)] than boys [2.0 (1.1, 3.0), P = 0.007], but SAT change (L) did not differ by race or sex. VAT change (L) was higher among white [0.1 (0.1, 0.1)] than among black adolescents [0.0 (0.0, 0.1), P = 0.003] and boys [0.1 (0.1, 0.1)] than girls [0.0 (0.0, 0.1), P = 0.034].
CONCLUSIONS
Sex and race differences in the deposition and accumulation of excess fat are important considerations for understanding obesity prevalence and obesity-related disease risk among adolescents.This trial was registered at clinicaltrials.gov as NCT02784509.
Topics: Adiposity; Adolescent; Body Mass Index; Cross-Sectional Studies; Female; Humans; Intra-Abdominal Fat; Male; Obesity; Prospective Studies; Subcutaneous Fat
PubMed: 35544287
DOI: 10.1093/ajcn/nqac129 -
Hormone Molecular Biology and Clinical... Mar 2018Background Lipedema is a chronic disorder presenting in women during puberty or other times of hormonal change such as childbirth or menopause, characterized by... (Meta-Analysis)
Meta-Analysis Review
Background Lipedema is a chronic disorder presenting in women during puberty or other times of hormonal change such as childbirth or menopause, characterized by symmetric enlargement of nodular, painful subcutaneous adipose tissue (fat) in the limbs, sparing the hands, feet and trunk. Healthcare providers underdiagnose or misdiagnose lipedema as obesity or lymphedema. Materials and methods The benefits (friend) and negative aspects (foe) of lipedema were collected from published literature, discussions with women with lipedema, and institutional review board approved evaluation of medical charts of 46 women with lipedema. Results Lipedema is a foe because lifestyle change does not reduce lipedema fat, the fat is painful, can become obese, causes gait and joint abnormalities, fatigue, lymphedema and psychosocial distress. Hypermobility associated with lipedema can exacerbate joint disease and aortic disease. In contrast, lipedema fat can be a friend as it is associated with relative reductions in obesity-related metabolic dysfunction. In new data collected, lipedema was associated with a low risk of diabetes (2%), dyslipidemia (11.7%) and hypertension (13%) despite an obese average body mass index (BMI) of 35.3 ± 1.7 kg/m2. Conclusion Lipedema is a painful psychologically distressing fat disorder, more foe than friend especially due to associated obesity and lymphedema. More controlled studies are needed to study the mechanisms and treatments for lipedema.
Topics: Adiposity; Biomarkers; Body Mass Index; Comorbidity; Humans; Life Style; Lipedema; Severity of Illness Index; Subcutaneous Fat
PubMed: 29522416
DOI: 10.1515/hmbci-2017-0076