Browning of White Adipocytes in Fat Grafts Associated with Higher Level of Necrosis and Type 2 Macrophages Recruitment

Author(s):  
Tong Liu ◽  
Su Fu ◽  
Qian Wang ◽  
Hao Cheng ◽  
Dali Mu ◽  
...  

Abstract Background Induced browning adipocytes were assumed less viable and more prone to necrosis for their hypermetabolic property. Our previous study showed that browning of adipocytes was more evident in fat grafts with necrosis in humans. Objectives We aimed to estimate whether fat-transfer-induced browning biogenesis was associated with necrosis and its potential inflammation mechanisms in murine models. Methods Human subcutaneous adipose from thigh or abdomen of 5 patients via liposuction were injected in 100µl or 500µl (n=20 per group) into the dorsal flank of 6-8-week female nude mice fed with normal chow diet, and harvested after 2, 4, 8 and 12 weeks. Control groups did not receive any grafting procedures (sham operation), where lipoaspirates were analyzed immediately after harvest. Histology and electronic microscopy, immunological analyses of browning markers, necrosis marker, and type I/II macrophages markers in mice were performed. Results Histology and electronic microscopy showed browning adipocytes in in fat grafts with higher level of necrosis (0.435±0.017pg/ml for cleaved caspase-3, **p<0.01), IL-6(749.0±134.1pg/ml,***p<0.001) and infiltration of type 2 macrophage profiles in mice(2-fold increase, *p<0.05). Conclusions Browning of adipocytes induced by fat transfer in mice is in parallel with post-grafting necrotic levels, associated with elevated IL-6 and activated M2 macrophages profiles which promote browning development.

Author(s):  
Tong Liu ◽  
Su Fu ◽  
Qian Wang ◽  
Hao Cheng ◽  
Dali Mu ◽  
...  

Abstract Background Browning adipocytes induced by burn and cancer were assumed less viable and more prone to necrosis for their hypermetabolic properties. Recent studies have shown browning of white adipose after fat engraftment in mice. Objectives We tend to evaluate whether fat transfer could induce browning biogenesis in fat grafts in humans and if it is associated with graft necrosis. Methods Necrotic adipose grafts were excised from 11 patients diagnosed with fat necrosis after fat grafting or flap transfer. Non-necrotic fat grafts were from 5 patients undergoing revisionary surgeries after flap transfer. Histology and electronic microscopy, protein and gene expression of browning related marker analyses were performed. Results Fat grafts with necrosis demonstrated a higher gene expression level of uncoupling protein-1 (>5-fold increase, **p<0.01), a master beige adipocyte marker, than non-necrotic fat grafts. Electronic microscopy and histology showed that browning adipocytes were presented in necrotic adipose in patients. Conclusions Fat transfer induced browning adipocytes in patients and was evident in patients with post grafting necrosis.


2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Boris L. Vaisman ◽  
Tatyana G. Vishnyakova ◽  
Lita A. Freeman ◽  
Marcelo J. Amar ◽  
Stephen J. Demosky ◽  
...  

The role of scavenger receptor class B, type I (SR-BI) in endothelial cells (EC) was examined in several novel transgenic mouse models expressing SR-BI in endothelium of mice with normal C57Bl6/N, apoE-KO, orScarb1-KO backgrounds. Mice were also created expressing SR-BI exclusively in endothelium and liver. Endothelial expression of the Tie2-Scarb1transgene had no significant effect on plasma lipoprotein levels in mice on a normal chow diet but on an atherogenic diet, significantly decreased plasma cholesterol levels, increased plasma HDL cholesterol (HDL-C) levels, and protected mice against atherosclerosis. In 8-month-old apoE-KO mice fed a normal chow diet, the Tie2-Scarb1transgene decreased aortic lesions by 24%. Mice expressing SR-BI only in EC and liver had a 1.5 ± 0.1-fold increase in plasma cholesterol compared to mice synthesizing SR-BI only in liver. This elevation was due mostly to increased HDL-C. In EC culture studies, SR-BI was found to be present in both basolateral and apical membranes but greater cellular uptake of cholesterol from HDL was found in the basolateral compartment. In summary, enhanced expression of SR-BI in EC resulted in a less atherogenic lipoprotein profile and decreased atherosclerosis, suggesting a possible role for endothelial SR-BI in the flux of cholesterol across EC.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Junling Yang ◽  
Ken-Ichiro Fukuchi

Obesity significantly increases the risk of developing type 2 diabetes mellitus and other metabolic diseases. Obesity is associated with chronic low-grade inflammation in white adipose tissues, which is thought to play an essential role in developing insulin resistance. Many lines of evidence indicate that toll-like receptors (TLRs) and their downstream signaling pathways are involved in development of chronic low-grade inflammation and insulin resistance, which are associated with obesity. Mice lacking molecules positively involved in the TLR signaling pathways are generally protected from high-fat diet-induced inflammation and insulin resistance. In this study, we have determined the effects of genetic deficiency of toll/interleukin-1 receptor-domain-containing adaptor-inducing interferon-β (TRIF) on food intake, bodyweight, glucose metabolism, adipose tissue macrophage polarization, and insulin signaling in normal chow diet-fed mice to investigate the role of the TRIF-dependent TLR signaling in adipose tissue metabolism and inflammation. TRIF deficiency (TRIF−/−) increased food intake and bodyweight. The significant increase in bodyweight in TRIF−/− mice was discernible as early as 24 weeks of age and sustained thereafter. TRIF−/− mice showed impaired glucose tolerance in glucose tolerance tests, but their insulin tolerance tests were similar to those in TRIF+/+ mice. Although no difference was found in the epididymal adipose mass between the two groups, the percentage of CD206+ M2 macrophages in epididymal adipose tissue decreased in TRIF−/− mice compared with those in TRIF+/+ mice. Furthermore, activation of epididymal adipose AKT in response to insulin stimulation was remarkably diminished in TRIF−/− mice compared with TRIF+/+ mice. Our results indicate that the TRIF-dependent TLR signaling contributes to maintaining insulin/AKT signaling and M2 macrophages in epididymal adipose tissue under a normal chow diet and provide new evidence that TLR4-targeted therapies for type 2 diabetes require caution.


Author(s):  
Guanghao Qi ◽  
Nilanjan Chatterjee

Abstract Background Previous studies have often evaluated methods for Mendelian randomization (MR) analysis based on simulations that do not adequately reflect the data-generating mechanisms in genome-wide association studies (GWAS) and there are often discrepancies in the performance of MR methods in simulations and real data sets. Methods We use a simulation framework that generates data on full GWAS for two traits under a realistic model for effect-size distribution coherent with the heritability, co-heritability and polygenicity typically observed for complex traits. We further use recent data generated from GWAS of 38 biomarkers in the UK Biobank and performed down sampling to investigate trends in estimates of causal effects of these biomarkers on the risk of type 2 diabetes (T2D). Results Simulation studies show that weighted mode and MRMix are the only two methods that maintain the correct type I error rate in a diverse set of scenarios. Between the two methods, MRMix tends to be more powerful for larger GWAS whereas the opposite is true for smaller sample sizes. Among the other methods, random-effect IVW (inverse-variance weighted method), MR-Robust and MR-RAPS (robust adjust profile score) tend to perform best in maintaining a low mean-squared error when the InSIDE assumption is satisfied, but can produce large bias when InSIDE is violated. In real-data analysis, some biomarkers showed major heterogeneity in estimates of their causal effects on the risk of T2D across the different methods and estimates from many methods trended in one direction with increasing sample size with patterns similar to those observed in simulation studies. Conclusion The relative performance of different MR methods depends heavily on the sample sizes of the underlying GWAS, the proportion of valid instruments and the validity of the InSIDE assumption. Down-sampling analysis can be used in large GWAS for the possible detection of bias in the MR methods.


Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1343
Author(s):  
Iwona Puzio ◽  
Dorota Graboś ◽  
Marek Bieńko ◽  
Radosław P. Radzki ◽  
Aneta Nowakiewicz ◽  
...  

The aim of the present study was to determine the effect of administration of Camelina sativa oil (CO) as a source of polyunsaturated fatty acids (PUFA) on bone parameters in ovariectomized rats (OVX). Overall, 40 10-week-old healthy female Wistar rats were divided into 4 groups with 10 animals in each. Rats in the control group (SHO) were subjected to a sham operation, whereas experimental rats (OVX) were ovariectomized. After a 7-day recovery period, the SHO the rats received orally 1 mL of physiological saline for the next 6 weeks. The OVX rats received orally 1 mL of physiological saline (OVX-PhS), 5 g/kg BW (OVX-CO5), or 9 g/kg BW (OVX-CO9) of camelina oil. The use of camelina oil had a significant effect on body weight, lean mass, and fat mass. The camelina oil administration suppressed the decrease in the values of some densitometric, tomographic, and mechanical parameters of femur caused by estrogen deficiency. The CO treatment increased significantly the serum level of osteocalcin and decreased the serum level of C-terminal telopeptide of type I collagen in the OVX rats. In conclusion, camelina oil exerts a positive osteotropic effect by inhibiting ovariectomy-induced adverse changes in bones. Camelina oil supplementation can be used as an efficient method for improving bone health in a disturbed state. However, further research must be carried out on other animal species supplemented with the oil.


2021 ◽  
Vol 22 (9) ◽  
pp. 4553
Author(s):  
Satoshi Fujisawa ◽  
Motoshi Komatsubara ◽  
Naoko Tsukamoto-Yamauchi ◽  
Nahoko Iwata ◽  
Takahiro Nada ◽  
...  

Orexin is expressed mainly in the hypothalamus and is known to activate the hypothalamic–pituitary–adrenal (HPA) axis that is involved in various stress responses and its resilience. However, the effects of orexin on the endocrine function of pituitary corticotrope cells remain unclear. In this study, we investigated the roles of orexin A in pro-opiomelanocortin (POMC) transcription using mouse corticotrope AtT20 cells, focusing on the bone morphogenetic protein (BMP) system expressed in the pituitary. Regarding the receptors for orexin, type 2 (OXR2) rather than type 1 (OX1R) receptor mRNA was predominantly expressed in AtT20 cells. It was found that orexin A treatment enhanced POMC expression, induced by corticotropin-releasing hormone (CRH) stimulation through upregulation of CRH receptor type-1 (CRHR1). Orexin A had no direct effect on the POMC transcription suppressed by BMP-4 treatment, whereas it suppressed Smad1/5/9 phosphorylation and Id-1 mRNA expression induced by BMP-4. It was further revealed that orexin A had no significant effect on the expression levels of type I and II BMP receptors but upregulated inhibitory Smad6/7 mRNA and protein levels in AtT20 cells. The results demonstrated that orexin A upregulated CRHR signaling and downregulated BMP-Smad signaling, leading to an enhancement of POMC transcription by corticotrope cells.


2021 ◽  
Vol 12 (3) ◽  
Author(s):  
Mi Tian ◽  
Jingjing Wang ◽  
Shangming Liu ◽  
Xinyun Li ◽  
Jingyuan Li ◽  
...  

AbstractThe liver plays an important role in lipid and glucose metabolism. Here, we show the role of human antigen R (HuR), an RNA regulator protein, in hepatocyte steatosis and glucose metabolism. We investigated the level of HuR in the liver of mice fed a normal chow diet (NCD) and a high-fat diet (HFD). HuR was downregulated in the livers of HFD-fed mice. Liver-specific HuR knockout (HuRLKO) mice showed exacerbated HFD-induced hepatic steatosis along with enhanced glucose tolerance as compared with control mice. Mechanistically, HuR could bind to the adenylate uridylate-rich elements of phosphatase and tensin homolog deleted on the chromosome 10 (PTEN) mRNA 3′ untranslated region, resulting in the increased stability of Pten mRNA; genetic knockdown of HuR decreased the expression of PTEN. Finally, lentiviral overexpression of PTEN alleviated the development of hepatic steatosis in HuRLKO mice in vivo. Overall, HuR regulates lipid and glucose metabolism by targeting PTEN.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
F Fioravanti ◽  
P.G Golzio ◽  
M.L Carbone ◽  
A Panarelli ◽  
M Gagliardi ◽  
...  

Abstract Background and aim Myotonic Dystrophy (MD) is the most common inherited muscular dystrophy of the adult. Cardiac manifestation, including arrhythmias and conduction disorders, contributes significantly to the morbidity and mortality of the disease. The transition from a subclinical form of cardiac involvement to potentially life-threating manifestations is highly variable and not yet entirely understood. Aim of this work is to evaluate whether PQ interval (PQi) prolongation could be a reliable marker to predict left and right ventricle impairment and the necessity of a stricter monitoring. Methods In this retrospective cohort study, we selected all consecutive patients with a confirmed diagnosis of MD (type 1 and type 2) referred to our Centre. We performed clinical, laboratoristic and instrumental assessments (every 3, 6 or 12 months), tailored on each patient's features. Every patient was treated according to the latest guidelines for pharmacological and device therapy. ECG (recorded at 25 and 50 mm/sec), 24h ECG Holter and transthoracic echocardiography were performed at least yearly. Cardiac Magnetic Resonance was requested to better stratify intermediate risk patients to implantable device therapy. Results A total of 72 patients (age 48±15 years, 39% female) were included in the analysis. Patients with MD type 1 and type 2 were referred to our Centre after a mean period of 12 years (SD ±8 years) from initial diagnosis. After a mean follow-up of 5 years (±4 years), 8 patients died (mean age at death: 60±12.4 years), all of them for respiratory insufficiency. We evaluated PQ interval (PQi) evolution and type I AVB onset. No statistically significant differences emerged when stratifying for type I AVB. Nevertheless, a PQi increase of more than 20 ms during the follow-up (even if PQ <200 ms) is significantly associated with lower values of TAPSE and greater LVEDD, while no differences emerged for LVEF, dyastolic function and other echocardiographic parameters. Moreover, the evolution of PQ interval is associated with an increasing number of supraventricular arrhythmias and a worse prognosis (shorter interval from first cardiac symptom to death, p 0.025), despite optimal medical therapy. Conclusions Although relatively rare, MD is a challenge for present Cardiologists. How and when to treat those patients is not codified in guidelines or consensus papers. This study suggests PQi variation as a proxy for critical evolution of MD cardiac involvement. ECG and its modification during lifetime seem pivotal for these patients' care, qualifying as a red flag for stringent follow-up. Further evidences, on larger cohorts, are needed to validate these findings. Funding Acknowledgement Type of funding source: None


2019 ◽  
pp. 105984051986174
Author(s):  
Suzuho Shimasaki ◽  
Pamela Brunner Nii ◽  
Lisa Davis ◽  
Erin Bishop ◽  
Cari Berget ◽  
...  

Type I diabetes (T1D) is one of the most common childhood diseases and Type 2 diabetes (T2D) is increasing at alarming rates. Given that children spend a great percentage of their time in school, this setting is a critical environment for models of care that lead to better management of this and other health conditions. The School Nurses Managing Diabetes Care ECHO was offered to Colorado school nurses to build their capacity in providing evidence-based management of T1D. The purpose of this effort was to (1) determine whether or not the model could be used as a tool of collaboration and dissemination for school nurses across Colorado and (2) assess the effectiveness of the “School Nurses Managing Diabetes Care” ECHO learning series. Post-series survey results demonstrated a 25% increase in self-efficacy ratings, moving learners from “average among my peers” toward “competent.” Additionally, all respondents planned to make one or more practice changes to improve care for students with T1D. Expanding the use of the ECHO model to implement intensive management of children and youth with T1D is critically important as rates of this and other chronic conditions continue to increase.


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