Mitochondrial Ca2+ signaling is a hallmark of specific adipose tissue-cancer crosstalk.

Obesity is associated with increased risk and worse prognosis of many tumours including those of the breast and of the esophagus. Adipokines released from the peritumoural adipose tissue promote the metastatic potential of cancer cells, suggesting the existence of a crosstalk between the adipose tissue and the surrounding tumour. Mitochondrial Ca2+ signaling contributes to the progression of carcinoma of different origins. However, whether adipocyte-derived factors modulate mitochondrial Ca2+ signaling in tumours is unknown. Here, we show that conditioned media derived from adipose tissue cultures (ADCM) enriched in precursor cells impinge on mitochondrial Ca2+ homeostasis of target cells. Moreover, in modulating mitochondrial Ca2+ responses, a univocal crosstalk exists between visceral adipose tissue-derived preadipocytes and esophageal cancer cells, and between subcutaneous adipose tissue-derived preadipocytes and triple-negative breast cancer cells. An unbiased metabolomic analysis of ADCM identified creatine and creatinine for their ability to modulate mitochondrial Ca2+ uptake, migration and proliferation of esophageal and breast tumour cells, respectively.

A macrophage-collagen fragment axis mediates subcutaneous adipose tissue remodeling in mice.

Efficient removal of fibrillar collagen is essential for adaptive subcutaneous adipose tissue (SAT) expansion that protects against ectopic lipid deposition during weight gain. Here, we used mice to further define the mechanism for this collagenolytic process. We show that loss of collagen type-1 (CT1) and increased CT1-fragment levels in expanding SAT are associated with proliferation of resident M2-like macrophages that display increased CD206-mediated engagement in collagen endocytosis compared to chow-fed controls. Blockage of CD206 during acute high-fat diet-induced weight gain leads to SAT CT1-fragment accumulation associated with elevated inflammation and fibrosis markers. Moreover, these SAT macrophages' engagement in collagen endocytosis is diminished in obesity associated with elevated levels collagen fragments that are too short to assemble into triple helices. We show that such short fragments provoke M2-macrophage proliferation and fibroinflammatory changes in fibroblasts. In conclusion, our data delineate the importance of a macrophage-collagen fragment axis in physiological SAT expansion. Therapeutic targeting of this process may be a means to prevent pathological adipose tissue remodeling, which in turn may reduce the risk for obesity-related metabolic disorders.

Clinical Characteristics of Patients With Acquired Partial Lipodystrophy: A Multicenter Retrospective Study.

BACKGROUND: Barraquer-Simons syndrome (BSS) is a rare, acquired form of lipodystrophy characterized by progressive loss of upper body subcutaneous fat, which affects face, upper limbs, and trunk. The pathogenesis of the disease is not entirely known and may involve autoimmune mechanisms. AIM: This study aimed to provide a comprehensive picture of the clinical, immunological, and metabolic features of a large cohort of patients with BSS. Our primary objectives included the validation of existing diagnostic tools, the evaluation of novel diagnostic approaches, and the exploration of potential disease triggers or genetic predispositions. SUBJECTS AND METHODS: Twenty-six patients were diagnosed with BSS based on accepted criteria defined by international guidelines. Anthropometric parameters, biochemical tests, organ- and non-organ-specific autoantibodies, HLA status, and screening of the LMNB2 gene were performed. RESULTS: Patients were predominantly females (73%); fat loss occurred mostly during childhood (77%) at a median age of 8 years. Among various anthropometric measures, the ratio between the proportion of fat mass in upper limbs and lower limbs showed the best predictive value for diagnosis. A total of 11.5% of patients had diabetes, 34.6% dyslipidemia, and 26.9% hepatic steatosis. Seventy-five percent of children and 50% of adults had C3 hypocomplementemia; 76% of patients were positive for 1 or more autoantibodies. HLA-DRB1 11:03 had higher allelic frequencies compared with the general population. A single variant in the LMNB2 gene was found in 1 patient. CONCLUSION: BSS has a childhood onset and is often associated with autoimmune diseases. Skinfold thickness measurements and fat assessment by dual energy X-ray absorptiometry are useful tools to identify the disease. C3 hypocomplementemia and the presence of autoantibodies may be used as additional diagnostic supportive criteria but the prevalence of C3 hypocomplementemia may be lower than previously reported.

Diagnostic imaging in lipedema: A systematic review.

BACKGROUND: Diagnosing lipedema remains a challenge due to its heterogeneous presentation, co-existing diseases, and the lack of objective diagnostic imaging. OBJECTIVE: This systematic review aims to outline the currently available diagnostic imaging methods to characterize lipedema in the legs along with their diagnostic performance. METHODS: PubMed, Embase, Google Scholar, Scopus, and Web of Science were searched. The quality assessment of diagnostic accuracy studies (QUADAS) tool was used for quality assessment. RESULTS: Thirty-two studies describing a total of 1154 patients with lipedema were included for final analysis. Features for lipedema have been defined using ultrasound (increased subcutaneous adipose tissue), lymphoscintigraphy (slowing of the lymphatic flow and a frequent asymmetry between the lower extremities), computed tomography (symmetrical bilateral soft tissue enlargement without either skin thickening or subcutaneous edema), magnetic resonance imaging (increased subcutaneous adipose tissue), MR lymphangiography (enlarged lymphatic vessels up to a diameter of 2 mm), and dual-energy X-ray absorptiometry (fat mass in the legs adjusted for body mass index (BMI) ≥ 0.46 or fat mass in the legs adjusted for total fat mass ≥ 0.384). CONCLUSION: The diagnostic performance of currently available imaging modalities for assessing lipedema is limited. Prospective studies are needed to evaluate and compare the diagnostic performance of each imaging modality. Imaging techniques focusing on the pathogenesis of the disease are needed.

AKR1C1 and hormone metabolism in lipedema pathogenesis: a computational biology approach.

OBJECTIVE: Lipedema is an autosomal dominant genetic disease that mainly affects women. It is characterized by excess deposition of subcutaneous adipose tissue, pain, and anxiety. The genetic and environmental etiology of lipedema is still largely unknown. Although considered a rare disease, this pathology has been suggested to be underdiagnosed or misdiagnosed as obesity or lymphedema. Steroid hormones seem to be involved in the pathogenesis of lipedema. Indeed, aldo-keto reductase family 1 member C1 (AKR1C1), a gene coding for a protein involved in steroid hormones metabolism, was the first proposed to be correlated with lipedema. PATIENTS AND METHODS: In this study, we employed a molecular dynamics approach to assess the pathogenicity of AKR1C1 genetic variants found in patients with lipedema. Moreover, we combined information theory and structural bioinformatics to identify AKR1C1 polymorphisms from the gnomAD database that could predispose to the development of lipedema. RESULTS: Three genetic variants in AKR1C1 found in patients with lipedema were disruptive to the protein's function. Furthermore, eight AKR1C1  variants found in the general population could predispose to the development of lipedema. CONCLUSIONS: The results of this study provide evidence that AKR1C1 may be a key gene in lipedema pathogenesis, and that common polymorphisms could predispose to lipedema development.

Characterization of somatic mutations in the pathogenesis of lipedema.

Background: Lipedema, a complex and enigmatic adipose tissue disorder, remains poorly understood despite its significant impact on the patients' quality of life. Genetic investigations have uncovered potential contributors to its pathogenesis, including somatic mutations, which are nonheritable genetic alterations that can play a pivotal role in the development of this disease. Aim: This review aims to elucidate the role of somatic mutations in the etiology of lipedema by examining their implications in adipose tissue biology, inflammation, and metabolic dysfunction. Results: Studies focusing on leukocyte clones, genetic alterations like TET2 and DNMT3A, and the intricate interplay between adipose tissue and other organs have shed light on the underlying mechanisms driving lipedema. From the study of the scientific literature, mutations to genes correlated to three main pathways could be involved in the somatic development of lipedema: genes related to mitochondrial activity, genes related to localized disorders of subcutaneous adipose tissue, and genes of leukocyte clones. Conclusions: The insights gained from these diverse studies converge to highlight the complex genetic underpinnings of lipedema and offer potential avenues for therapeutic interventions targeting somatic mutations to alleviate the burden of this condition on affected individuals.

Pancreatitis, panniculitis and polyarthritis (PPP) syndrome.

A young male presented with intermittent high-grade fever, asymmetric polyarthritis and erythematous, tender nodules over left shin for 2 months duration. He had a history of alcohol dependence with multiple episodes of acute pancreatitis. With polyarthritis progressing relentlessly, unresponsive to non-steroidal anti-inflammatory drugs and steroids, a provisional diagnosis of sarcoidosis was considered. Indeed, he was treated with azathioprine and rituximab with no effect. Biopsy of the skin nodule revealed subcutaneous fat necrosis, foam cells, deposition of eosinophilic amorphous material and calcification. Synovial fluid aspiration from the arthritic knee obtained purulent but surprisingly culture-negative material, rich in triglycerides. Abdominal CT confirmed chronic pancreatitis. Final diagnosis of pancreatitis, panniculitis and polyarthritis (PPP) syndrome was made. He underwent surgical pancreatic ductal drainage leading to complete remission of symptoms. PPP syndrome triad occurs due to leakage of pancreatic enzymes into systemic circulation and subsequent fat necrosis. Surgical drainage of pancreatic duct is often curative.

Associations between weight change, knee subcutaneous fat and cartilage thickness in overweight and obese individuals: 4-Year data from the osteoarthritis initiative.

OBJECTIVE: To assess (i) the impact of changes in body weight on changes in joint-adjacent subcutaneous fat (SCF) and cartilage thickness over 4 years and (ii) the relation between changes in joint-adjacent SCF and knee cartilage thickness. DESIGN: Individuals from the Osteoarthritis Initiative (total=399) with > 10% weight gain (n=100) and > 10% weight loss (n=100) over 4 years were compared to a matched control cohort with less than 3% change in weight (n=199). 3.0T Magnetic Resonance Imaging (MRI) of the right knee was performed at baseline and after 4 years to quantify joint-adjacent SCF and cartilage thickness. Linear regression models were used to evaluate the associations between the (i) weight change group and 4-year changes in both knee SCF and cartilage thickness, and (ii) 4-year changes in knee SCF and in cartilage thickness. Analyses were adjusted for age, sex, baseline body mass index (BMI), tibial diameter (and weight change group in analysis (ii)). RESULTS: Individuals who lost weight over 4-years had significantly less joint-adjacent SCF (beta range, medial/lateral joint sides: 2.2-4.2 mm, p < 0.001) than controls; individuals who gained weight had significantly greater joint-adjacent SCF than controls (beta range: -1.4 to -3.9 mm, p < 0.001). No statistically significant associations were found between weight change and cartilage thickness change. However, increases in joint-adjacent SCF over 4 years were significantly associated with decreases in cartilage thickness (p = 0.04). CONCLUSIONS: Weight change was associated with joint-adjacent SCF, but not with change in cartilage thickness. However, 4-year increases in joint-adjacent SCF were associated with decreases in cartilage thickness independent of baseline BMI and weight change group.

Lipedema stage affects adipocyte hypertrophy, subcutaneous adipose tissue inflammation and interstitial fibrosis.

Introduction: Lipedema is a painful subcutaneous adipose tissue (SAT) disease characterized by adipocyte hypertrophy, immune cell recruitment, and fibrosis in the affected areas. These features are thought to contribute to the development and progression of the condition. However, the relationship between lipedema disease stage and the associated adipose tissue changes has not been determined so far. Methods: SAT biopsies of 32 lipedema patients, ranging across the pathological stages I to III, and 14 BMI- and age-matched controls were harvested from lipedema-affected thighs and non-symptomatic lower abdominal regions. Histological and immunohistochemical (IHC) staining and expression analysis of markers for adipogenesis, immunomodulation, and fibrosis were performed on the tissue biopsies. Results: Lipedema patients showed increased adipocyte areas and a stage-dependent shift towards larger cell sizes in the thighs. Lipedema SAT was linked with increased interstitial collagen accumulation in the thighs, but not the lower abdominal region when compared to controls. There was a trend toward progressive SAT fibrosis of the affected thighs with increasing lipedema stage. Elevated gene expression levels of macrophage markers were found for thigh SAT biopsies, but not in the abdominal region. IHC staining of lipedema thigh biopsies confirmed a transiently elevated macrophage polarization towards an M2-like (anti-inflammatory) phenotype. Conclusions: In summary, lipedema SAT is associated with stage-dependent adipocyte hypertrophy, stage-progressive interstitial fibrosis and elevated proportion of M2-like macrophages. The character of the inflammatory response differs from primary obesity and may possess an essential role in the development of lipedema.

Lower subcutaneous fat index predicts bone metastasis in breast cancer.

BACKGROUND: Bone metastases affect 50% to 70% of breast cancer (BC) patients and have a high mortality rate. Adipose tissue loss plays a pivotal role in the progression of cancer. OBJECTIVE: This study aims to evaluate the prognostic value of adipose tissue for bone metastasis in BC patients. METHODS: 517 BC patients were studied retrospectively. Patients' characteristics before the surgery were collected. Quantitative measurements of the subcutaneous fat index (SFI) were performed at the level of the eleventh thoracic vertebra. In order to adjust for the heterogeneity between the low SFI and high SFI groups, propensity score matching (PSM) was used. The Kaplan-Meier method was used to estimate the 5-year bone metastatic incidence. The prognostic analysis was performed with the Cox regression models. RESULTS: Compared with the patients without bone metastasis, the patients with bone metastasis had reduced SFI levels. In addition, Kaplan-Meier analysis revealed that patients with low SFI were more likely to develop bone metastases. The independent predictive value of SFI for bone metastases was confirmed by Cox regression analysis. The survival analysis was repeated after PSM with a 1:1 ratio, yielding similar results (P< 0.05). CONCLUSIONS: SFI is an independent predictor of bone metastasis in BC patients.

Common Histological Features Suggesting Enchondral Ossification Pathways in Calciphylaxis of Various Origins: A Study of Human Subcutaneous Tissue Biopsies.

Calciphylaxis is a rare, yet underdiagnosed condition causing high mortality in patients with severe renal and cardiovascular disease. Since knowledge of the pathophysiology of calciphylaxis is limited, a differential analysis of histological alterations in patient subgroups with various comorbidities might expose different disease phenotypes and allow deeper insights into the pathophysiology of the condition. Histological markers of osteogenesis and calcification were investigated in a group of 18 patients with clinically and histologically verified calciphylaxis, using immunohistochemical staining. Analysis of staining intensity and distribution of marker proteins in histological structures was performed to evaluate distinct patterns between subgroups with different clinical comorbidities in comparison with a control group. In all cases, immunohistochemical staining for bone matrix proteins, bone-morphogenic proteins and matrix-Gla proteins co-localized with subcutaneous vascular and interstitial calcifications. Significant expression of bone-morphogenic protein-7 and active matrix-Gla protein was observed. Mortality was associated with renal comorbidities and increased expression of bone-morphogenic protein-7. However, no distinct histological patterns were found between subgroups with renal disease, warfarin intake or coexisting micro- and macro-angiopathies. The upregulation of osteogenic markers (including bone-morphogenic protein-7) plays a major role in the development of calciphylaxis. Clinical outcome correlates with kidney function and phosphate handling, suggesting different pathophysiological mechanisms. However, biopsy  at late-stage disease shows a common histological phenotype, involving enchondral ossification.

Adipose 'neighborhoods' collaborate to maintain metabolic health.

Body fat is stored in anatomically distinct adipose depots that vary in their cell composition and play specialized roles in systemic metabolic homeostasis via secreted products. Their local effects on nearby tissues (e.g. the gut and visceral adipose tissues) are increasingly recognized and this local crosstalk is being elucidated. The major subcutaneous fat depots, abdominal and gluteal-femoral, exert opposite effects on the risk of metabolic disease. The pace of research into developmental, sex, and genetic determinants of human adipose depot growth and function is rapidly accelerating, providing insight into the pathogenesis of metabolic dysfunction in persons with obesity.

A novel radiological index for the evaluation of cervical posterior subcutaneous fat tissue thickness and cervical spine degeneration: A retrospective study.

Obesity is an important risk factor linked to the incidence of both neck pain (NP) and intervertebral disc degeneration (IVDD). Subcutaneous fat tissue thickness (SFTT) has been proposed as a more effective biomarker than body mass index (BMI) when gauging body fat levels. This study was thus designed to explore the optimal SFTT cutoff value for differentiating between NP patients and asymptomatic individuals by using the subcutaneous fat index (SFI). Magnetic resonance imaging (MRI) records from NP patients and asymptomatic controls were compared to evaluate IVDD, the fatty infiltration of the paravertebral muscles, and Modic changes. Cervical SFTT was also assessed at multiple levels. SFTT at the C3 level was found to be significantly associated with NP, with respective optimal cutoff values of 9.64 mm and 8.21 mm for females and males. Females in this study cohort more frequently exhibited spine deterioration with an SFI > 9.64 mm as compared to males with an SFI > 8.21 mm. Cervical SFTT is strongly correlated with the degree of disc degeneration. IVDD, Modic changes, and fatty infiltration in the paravertebral muscles were all more prevalent among both males and females exhibiting SFTT at the C3 level that was above the defined cutoff value.

Secondary diffuse large B-cell breast lymphoma developed in subcutaneous fat layer of the breast with cardiac involvement.

We present a rare case of diffuse large B-cell lymphoma developed in subcutaneous fat layer of the breast with cardiac involvement. Radiologists should perform an image-guided biopsy for pathologic confirmation of breast lymphomas and avoidance of unnecessary invasive treatment.

The lipidomic and inflammatory profiles of visceral and subcutaneous adipose tissues are distinctly regulated by the SGLT2 inhibitor empagliflozin in Zucker diabetic fatty rats.

The pharmacological inhibition of sodium-glucose cotransporter 2 (SGLT2) has emerged as a treatment for patients with type 2 diabetes mellitus (T2DM), cardiovascular disease and/or other metabolic disturbances, although some of the mechanisms implicated in their beneficial effects are unknown. The SGLT2 inhibitor (SGLT2i) empagliflozin has been suggested as a regulator of adiposity, energy metabolism, and systemic inflammation in adipose tissue. The aim of our study was to evaluate the impact of a 6-week-empagliflozin treatment on the lipidome of visceral (VAT) and subcutaneous adipose tissue (SAT) from diabetic obese Zucker Diabetic Fatty (ZDF) rats using an untargeted metabolomics approach. We found that empagliflozin increases the content of diglycerides and oxidized fatty acids (FA) in VAT, while in SAT, it decreases the levels of several lysophospholipids and increases 2 phosphatidylcholines. Empagliflozin also reduces the expression of the cytokines interleukin-1 beta (IL-1ß), IL-6, tumor necrosis factor-alpha (TNFα), monocyte-chemotactic protein-1 (MCP-1) and IL-10, and of Cd86 and Cd163 M1 and M2 macrophage markers in VAT, with no changes in SAT, except for a decrease in IL-1ß. Empagliflozin treatment also shows an effect on lipolysis increasing the expression of hormone-sensitive lipase (HSL) in SAT and VAT and of adipose triglyceride lipase (ATGL) in VAT, together with a decrease in the adipose content of the FA transporter cluster of differentiation 36 (CD36). In conclusion, our data highlighted differences in the VAT and SAT lipidomes, inflammatory profiles and lipolytic function, which suggest a distinct metabolism of these two white adipose tissue depots after the empagliflozin treatment.

Subcutaneous fat infiltration into the dermal layer induces wrinkle formation.

BACKGROUND: Wrinkles appear with aging, producing an aged impression, but the mechanism of wrinkle formation has not yet been fully elucidated. We recently reported that subcutaneous fat infiltrates into the dermal layer with aging and impairs skin elasticity, but the contribution of this process to wrinkle formation is still unclear. PURPOSE: We aimed to clarify the contribution of dermal fat infiltration to wrinkle formation by analyzing the relationship between them in the forehead of female volunteers. METHODS: We measured the severity of fat infiltration in the forehead of 29 middle-aged female volunteers by means of ultrasonography. Fixed wrinkles present when the eyes were closed and wrinkles transiently formed when the eyes were open were evaluated using a photograph-based 6-grade evaluation system for each type of wrinkle. RESULTS: Fat infiltration at the forehead area was observed similarly to that in the cheek area as we reported previously. We found that opening the eyes induced the formation of stable transient wrinkles, the grade of which was significantly related to fat infiltration severity. Furthermore, fat infiltration was also significantly related to the severity of fixed wrinkles. Moreover, the severity of transient wrinkles was significantly related to that of fixed wrinkles. CONCLUSIONS: Our results suggest that fat infiltration into the dermal layer enhances transient wrinkle formation during facial expression by impairing the ability of the skin to resist deformation, thereby promoting fixed wrinkle formation. Therefore, fat infiltration is a critical cause of wrinkle formation.

Electrochemical lipolysis of subcutaneous adipose tissue in a porcine animal model.

OBJECTIVES: There is a considerable demand for noninvasive low-cost fat reduction methods with fewer side effects and shorter recovery times. This study aims to develop a fat-reduction method through electrochemical lipolysis of subcutaneous adipocytes using needle-based electrodes, body tissue fluids, and electrical current application. METHODS: Electrochemical lipolysis was performed by inserting a 4-pin needle electrode connected to a DC power supply into the pig's abdomen. Applied electrical current (0.5 and 1 mA) and treatment time (5 or 10 minutes) were varied systematically. Ultrasound imaging was performed before and after treatment to determine changes in fat thickness. Tissue samples were collected at 0, 2, and 4 weeks posttreatment for histological evaluation to determine the mechanism of action and the procedure's efficacy. RESULTS: Electrochemical subcutaneous adipose tissue lipolysis in a porcine model was achieved through hydrolysis of physiologic fluid within the vicinity of the inserted electrode where an electric current is applied, leading to localized disruption of fat cell membranes and necrosis. Electric current configuration 1.0 mA showed more pronounced lipolysis effects applied for 10 minutes, significantly decreasing adipocyte content per treatment area. The electrochemical treatment method also stimulates collagen synthesis, which helps reduce fat. CONCLUSIONS: Electrochemical lipolysis is a potential new noninvasive localized technique to reduce fat. The treatment method induces fat cell necrosis via in situ reduction-oxidation reaction by the electrochemical activation of physiologic fluid in the surrounding tissue. Electrochemical lipolysis is a simple, low-cost, fat-reducing treatment method without harmful side effects.

Rapid cytologic diagnosis of subcutaneous fat necrosis of the newborn.

Subcutaneous fat necrosis of the newborn is a rare self-limited panniculitis that classically presents within the first few weeks of life. The diagnosis is typically clinical, but some cases require skin biopsy with hematoxylin and eosin stain for confirmation. We report a previously undocumented rapid diagnostic protocol that involves collecting a small amount of exudate from a suppurative lesion, placement onto a slide without fixation, and simply viewing the material under a microscope. This novel and practical method of diagnosis reveals doubly refractile crystals diagnostic of subcutaneous fat necrosis without a biopsy, which may be helpful for rapid diagnosis or use in low resource settings.