Effect and Mechanism of Total Saponins from Panax Japonicus on White Adipose Tissue Browning/Brown Adipose Tissue Activation in High-fat Diet-induced Mice / 中国实验方剂学杂志

ObjectiveTo investigate the effect and mechanism of total saponins from Panax japonicus （TSPJ） on white adipose tissue （WAT） browning/brown adipose tissue （BAT） activation in C57BL6/J male mice fed on a high-fat diet （HFD）. MethodThirty-two C57BL6/J male mice （8-week-old） were randomly divided into a normal group， a model group， a low-dose TSPJ group， and a high-dose TSPJ group. The mice in the low-dose and high-dose TSPJ groups were given TSPJ for four months by gavage at 25， 75 mg·kg-1·d-1， respectively， and those in the other groups were given 0.5% sodium carboxymethyl cellulose （CMC-Na） accordingly. After four months of feeding， all mice were placed at 4 ℃ for acute cold exposure， and the core body temperature was monitored. Subsequently， all mice were sacrificed， and BAT and inguinal WAT （iWAT） were separated rapidly to detect the corresponding indexes. Hematoxylin-eosin （HE） staining was used to observe the morphological changes in each group. The effect of TSPJ on the mRNA expression of uncoupling protein 1 （UCP1）， fatty acid-binding protein 4 （FABP4）， cytochrome C （CytC）， PR domain-containing protein 16 （PRDM16）， elongation of very long chain fatty acids protein 3 （ELOVL3）， peroxisome proliferator-activated receptor γ （PPARγ）， and peroxisome proliferator-activated receptor-γ coactivator-1α （PGC-1α） in iWAT and BAT was detected by Real-time polymerase chain reaction （Real-time PCR）. Western blot was also used to detect the protein expression of UCP1， PRDM16， PPARγ， and PGC-1α in BAT and iWAT of each group. The effect of TSPJ on UCP1 expression in BAT and iWAT was detected by immunohistochemistry. Result① Compared with the model group， TSPJ could decrease the body weight and proportions of iWAT and BAT in the HFD-induced mice （P<0.05， P<0.01）. ② The body temperature of mice in the model group decreased compared with that in the normal group in the acute cold exposure tolerance test （P<0.05）. The body temperature in the high-dose TSPJ group increased compared with that in the model group （P<0.01）. ③ Compared with the normal group， the model group showed increased adipocyte diameter in iWAT and BAT and decreased number of adipocytes per unit area. Compared with the model group， the TSPJ groups showed significantly reduced cell diameter and increased number of cells per unit area， especially in the high-dose TSPJ group. ④ Compared with the normal group， the model group showed decreased mRNA expression of FABP4， UCP1， CytC， PRDM16， ELOVL3， PGC-1α， and PPARγ in adipose tissues of mice （P<0.05， P<0.01）. Compared with the model group， after intervention with TSPJ， the mRNA expression was significantly up-regulated （P<0.05， P<0.01）. ⑤ Compared with the normal group， the model group showed decreased protein expression of UCP1， PRDM16， PPARγ， and PGC-1α in adipose tissues of mice （P<0.05， P<0.01）. Compared with the model group， after intervention with TSPJ， the protein expression increased significantly （P<0.05， P<0.01）. ConclusionTSPJ could induce the browning of iWAT/BAT activation and enhance adaptive thermogenesis in obese mice induced by HFD. The underlying mechanism may be attributed to the activation of the PPARγ/PGC-1α signaling pathway.

Microbiota intestinal y modulación del tejido adiposo en la patogénesis de la obesidad / Gut microbiota and modulation of adipose tissue in the pathogenesis of obesity

Las investigaciones realizadas durante el último siglo relacionadas con la descripción de la Microbiota Intestinal (MI) sugieren una relación concreta entre su composición y la salud del huésped. Su desregulación denominada disbiosis intestinal ha sido asociada a distintos tipos de enfermedades gastrointestinales, metabólicas, oncológicas e incluso psiquiátricas. Destacan numerosos reportes que han informado la condición de disbiosis en la obesidad, tanto en modelos animales como humanos de distintos grupos etarios y regiones del mundo. A su vez, la composición del microbioma también ha logrado asociarse a las diferentes comorbilidades de la obesidad, postulando que la MI posee influencia en la disfunción del tejido adiposo (TA), entendiendo que corresponde al principal modulador de la patogénesis de la obesidad. Sin embargo, aún no es posible establecer una explicación mecanicista plausible. Actualmente, la utilización de tecnologías multiómicas, junto con la evaluación de variables fisiológicas, nos podrían proporcionar una mejor comprensión a la incógnita planteada. Frente a esto, el presente trabajo tiene como objetivo revisar los últimos avances en la comprensión de la influencia de la microbiota intestinal en el TA y su contribución a los mecanismos relacionados con la patogénesis de la obesidad. Entre los principales mecanismos identificados, la evidencia reporta nexos fisiológicos entre la composición de la MI y la modulación de inflamación, permeabilidad intestinal y adipogénesis. Las vías implicadas derivan de la influencia de la disbiosis intestinal en el accionar de ácidos grasos de cadena corta, claudinas, macrófagos, oligosacáridos, entre otros. Los mecanismos implicados, principalmente estudiados en modelos animales, deberían ser considerados para su evaluación en próximos estudios longitudinales y experimentales en humanos con el fin de obtener una mayor comprensión sobre la implicancia de cada mecanismo en la patogenia global de la obesidad(AU)

The investigations carried out during the last century related to the description of the Gut Microbiota (GM) suggest a concrete relationship between its composition and the health of the host. Its deregulation called intestinal dysbiosis has been associated with different types of gastrointestinal, metabolic, oncological and even psychiatric diseases. Numerous reports that have described the condition of dysbiosis in obesity stand out, both in animal and human models of different age groups and regions of the world. In turn, the composition of the microbiome has also been associated with the different comorbidities of obesity, postulating that MI has an influence on adipose tissue (AT) dysfunction, understanding that it corresponds to the main modulator of the pathogenesis of obesity. However, it is not yet possible to establish a plausible mechanistic explanation. Currently, the use of multi-omics technologies, together with the evaluation of physiological variables, could provide us with a better understanding of the question raised. In view of this, this review aims to review the latest advances in understanding the influence of the intestinal microbiota on AT and its contribution to the mechanisms related to the pathogenesis of obesity. Among the main mechanisms identified, the evidence reports physiological links between the composition of GM and the modulation of inflammation, intestinal permeability and adipogenesis. The pathways involved derive from the influence of intestinal dysbiosis on the action of short-chain fatty acids, claudins, macrophages, oligosaccharides, among others. The mechanisms involved, mainly studied in animal models, should be considered for evaluation in future longitudinal and experimental studies in humans in order to obtain a better understanding of the implication of each mechanism in the global pathogenesis of obesity(AU)

El tejido adiposo, ¿solo un almacén de energía? / Adipose Tissue, Just an Energy Storage?

Resumen Cuando los alimentos cubren los requerimientos energéticos, el organismo almacena el exceso de calorías como glucógeno en el hígado y el músculo, y los triacilgliceroles en el tejido adiposo. Morfológica y funcionalmente se clasifica en blanco y pardo. El pardo tiene gran cantidad de mitocondrias, almacena los triacilgliceroles en vacuolas y disipa la energía en forma de calor; el blanco almacena energía en gotas lipídicas que ocupan la mayor parte de su volumen. Después de la ingesta de alimentos se libera insulina, lo que hace que externen GLUT4 para absorber glucosa. Los quilomicrones o las lipoproteínas de muy baja densidad (VLDL) transportan los triacilgliceroles a los depósitos de tejido adiposo. Durante el ayuno, por acción del glucagón, se liberan enzimas que degradarán a los tri, di y monogliceroles para liberar a los ácidos grasos. El tejido adiposo libera citocinas pro y antiinflamatorias, así como leptina, adiponectina que regulan el apetito y la saciedad. La proteína cinasa activada por AMP se activa como respuesta a una baja en la cantidad de energía de la célula y le ayuda a mantener un balance energético. En el adipocito promueve la degradación de los triacilgliceroles para liberar a los ácidos grasos que se emplearán como fuente energética. Se requiere de mayor cantidad de estudios para conocer más sobre la función del tejido adiposo como regulador del metabolismo y no solo como almacén de energía.

Abstract When food meets energy requirements, the body stores in the liver and in the muscle the excess of calories as glycogen and triacylglycerols in the adipose tissue. Morphologically and functionally, it is classified into white and brown tissues. Brown tissue has many large mitochondria and stores triacylglycerols in vacuoles and dissipates energy as heat; white tissue stores energy as lipid droplets that occupy most of the adipocyte's volume. After food intake insulin is released, which causes GLUT4 externalization into the cellular membrane to absorb glucose. Chylomicrons or VLDL transport triacylglycerols to adipose tissue depots. During fasting, by the action of glucagon, enzymes are released that will degrade tri-, di- and mono-glycerols to release fatty acids. Adipose tissue releases pro and anti-inflammatory cytokines, as well as leptin and adiponectin that regulate appetite and satiety. AMPK is activated in response to a decrease in the cell's energy and helps it to maintain its energetic balance. In the adipocyte, it promotes the degradation of triacylglycerols releasing fatty acids to be used as an energy source. More studies are needed to learn more about the function of adipose tissue as a regulator of the metabolism and not only as an energy storage.

A comprehensive morphometric study of visceral and subcutaneous adipose tissue depots in mice, hamsters and rats / Un estudio morfométrico completo de los depósitos de tejido adiposo visceral y subcutáneo en ratones, hámsters y ratas

SUMMARY: Adipose tissue morphology of different fat tissue depots can be described using the number of adipocytes and cell surface of adipocytes. This study deals with characteristics and morphometric analysis of white and brown adipose tissue depots in healthy adult laboratory mice, hamsters and rats of both sexes. The number of unilocular adipocytes in white adipose tissue differs from one adipose tissue depot to another, with the largest number of adipocytes in mice and a similar number in hamsters and rats. The smallest surface area and the largest percentage of small unilocular adipocytes were found in mice. White adipose tissue in hamsters and rats was predominantly made out of a larger percentage of medium-sized adipocytes and a smaller percentage of small and medium-sized adipocytes. Uncoupling protein 1 positive multilocular adipocytes were found in classic brown adipose tissue depots with larger percentages in mice (93.20 %) and hamsters (91.30 %), while rats had a smaller percentage (78.10 %). In white and brown adipose tissue, significant differences between species and both sexes within the same species were found, indicating the influence of sexual dimorphism. The presented morphometric results could serve as a basis for further studies concerning experimental animal models of metabolic disorders and obesity.

RESUMEN: La morfología del tejido adiposo de diferentes depósitos de tejido graso se puede describir utilizando el número de adipocitos y la superficie celular de los adipocitos. Este estudio analiza las características y el análisis morfométrico de los depósitos de tejido adiposo blanco y marrón en ratones, hamsters y ratas de laboratorio, adultos sanos de ambos sexos. El número de adipocitos uniloculares en el tejido adiposo blanco difiere de un depósito de tejido adiposo a otro, con el mayor número de adipocitos en ratones y un número similar en hámsteres y ratas. La superficie más pequeña y el mayor porcentaje de adipocitos uniloculares pequeños se encontraron en ratones. El tejido adiposo blanco en hámsteres y ratas estaba compuesto predominantemente por un mayor porcentaje de adipocitos de tamaño mediano y un porcentaje menor de adipocitos de tamaño pequeño y mediano. Los adipocitos multiloculares positivos para la proteína desacopladora 1 se encontraron en depósitos de tejido adiposo marrón clásico con mayores porcentajes en ratones (93,20 %) y hámsters (91,30 %), mientras que las ratas tenían un porcentaje menor (78,10 %). En el tejido adiposo blanco y pardo se encontraron diferencias significativas entre especies y entre ambos sexos dentro de una misma especie, lo que indica la influencia del dimorfismo sexual. Los resultados morfométricos presentados podrían servir como base para futuros estudios sobre modelos animales experimentales de trastornos metabólicos y obesidad.

Advances of targeted delivery vectors for inducing browning of white adipose tissue / 药学学报

Obesity has become an important inducer of many public diseases such as diabetes, endocrine disorders, and so on. Anti-obesity treatment has become a hot topic. Inhibiting fat synthesis and promoting fat decomposition are important ways of drug anti-obesity treatment. With the in-depth study of the distribution, morphology and function of adipose tissue, brown adipose tissue containing multi-compartment fat drops and rich mitochondria have attracted people's attention. Beige adipocytes which are similar to brown adipocytes in morphology and function have aroused great interest, such cells can be transformed from white adipocytes by external stimulation or browning agents. This process is called "white fat browning". The expression of promoting energy consumption proteins in these cells increase, so that the function of adipocytes changes from energy storage to energy consumption to increase excessive energy consumption in the body and reduce lipid accumulation. The browning of white adipose tissue has brought new ideas for obesity treatment, but the systemic administration of browning agent has the risk of adverse reactions to non-target tissues such as heart and central nervous system, which limits its application in inducing white fat browning. Browning agents to white adipose tissue can reduce its adverse reactions and improve its bioavailability by constructing a drug delivery system targeting white adipose tissue. In this review, the mechanism on browning of white adipose tissue, the commonly used browning agents and the targeted delivery carriers that induce browning of white adipose tissue are summarized.

Mice as an animal model for the study of adipose tissue and obesity / Ratones como modelo animal para el estudio del tejido adiposo y la obesidad

SUMMARY: The study of adipose tissue has gained increasing importance in the biomedical area due to its implications for health and obesity. Obesity is a situation of great concern mainly in the Western world due to its high prevalence and morbidity. Experimental studies on obesity often need a model where it is possible to carry out experiments, drug testing, and other therapeutic procedures, which are typically not possible in humans. Although several animals are used for obesity studies, rodents are by far the most used animals, and among rodents, mice are particularly indicated for this investigation. This mini review will introduce the challenging classification of obesity in rodents, paralleling human obesity, defining and classifying what an obese mouse is. The text will differentiate between white adipose tissue (WAT, aimed at endocrine secretion and lipogenesis) and brown adipose tissue (BAT, aimed at thermogenesis) and describe the browning process of white adipocytes in an adaptation to increase thermogenesis. The text will also describe the various types of body fat in mice with their differences and indications for investigation and teach how to recognize and dissect these fats. At the end of this introductory reading, the young researcher is expected to have acquired sufficient knowledge to start an experimental investigative project on obesity.

RESUMEN: El estudio del tejido adiposo ha ganado una importancia creciente en el área biomédica por sus implicaciones para la salud y la obesidad. La obesidad es una situación de gran preocupación, principalmente, en el mundo occidental debido a su alta prevalencia y morbilidad. Los estudios experimentales sobre la obesidad a menudo necesitan un modelo en el que sea posible realizar experimentos, pruebas de drogas y otros procedimientos terapéuticos, que normalmente no son posibles en humanos. Aunque se utilizan varios animales para estudios de obesidad, los roedores son, con mucho, los animales más utilizados y, entre los roedores, los ratones están especialmente indicados para esta investigación. Esta mini revisión presenta la desafiante clasificación de la obesidad en roedores, en paralelo con la obesidad humana, definiendo y clasificando qué es un ratón obeso. El texto diferencia entre tejido adiposo blanco (WAT, destinado a la secreción endocrina y lipogénesis) y tejido adiposo marrón (BAT, destinado a la termogénesis) y describe el proceso de pardeamiento de los adipocitos blancos en una adaptación para aumentar la termogénesis. El texto también describe los diversos tipos de grasa corporal en ratones con sus diferencias e indicaciones para la investigación y enseña cómo reconocer y diseccionar estas grasas. Al final de esta lectura introductoria, se espera que el joven investigador haya adquirido los conocimientos suficientes para iniciar un proyecto de investigación experimental sobre la obesidad.

Research and thinking of acupuncture on promoting white adipose tissue browning / 针刺研究

Acupuncture has become an effective approach in clinic for treating obesity, but its mechanism has not been clarified yet. A large number of researches have been conducted on the obesity mechanism in the aspects of neurophysiological regulation, feeding center regulation and peripheral digestion and absorption regulation at home and abroad. But, regarding the main storage site of excess energy, i．e. the remodeling and functional regulation of white adipose tissue (WAT), is still a new field in research. In the paper, focusing on the new filed of weight loss, in view of the promotion of WAT browning through the re-gulation of UCP1 and PPARγ signal pathway with acupuncture, the potential peripheral mechanism of acupuncture was explored on weight loss.

Quantification of Fat Concentration and Vascular Response in Brown and White Adipose Tissue of Rats by Spectral CT Imaging

Recent developments in natural products for white adipose tissue browning / 中国天然药物

Excess accumulation of white adipose tissue (WAT) causes obesity which is an imbalance between energy intake and energy expenditure. Obesity is a serious concern because it has been the leading causes of death worldwide, including diabetes, stroke, heart disease and cancer. Therefore, uncovering the mechanism of obesity and discovering anti-obesity drugs are crucial to prevent obesity and its complications. Browning, inducing white adipose tissue to brown or beige (brite) fat which is brown-like fat emerging in WAT, becomes an appealing therapeutic strategy for obesity and metabolic disorders. Due to lack of efficacy or intolerable side-effects, the clinical trials that promote brown adipose tissue (BAT) thermogenesis and browning of WAT have not been successful in humans. Obviously, more specific means still need to be developed to activate browning of white adipose tissue. In this review, we summarized seven kinds of natural products (alkaloids, flavonoids, terpenoids, long chain fatty acids, phenolic acids, else and extract) promoting white adipose tissue browning which can ameliorate the metabolic disorders, including obesity, dislipidemia, insulin resistance and diabetes. Since natural products are important drug sources and the browning property plays a significant role in not only obesity treatment but also in type 2 diabetes (T2DM) improvement, natural products of inducing browning may be an irreplaceable drug discovery orientation for obesity, diabetes and even other metabolic disorders.

Comparison of blood glucose-lowering function of transplant islets between subcutaneous adipose tissues of inguinal region and renal capsule in mice / 器官移植

Objective To compare the effect of transplant islets between the subcutaneous inguinal white adipose tissues and renal capsule in the treatment of type 1 diabetes mellitus in mouse models. Methods The mice with type 1 diabetes mellitus undergoing islet transplantation were divided into the white adipose group (n=10) and renal capsule group (n=10). The islets were isolated, purified and transplanted to the subcutaneous white adipose tissues of inguinal region and renal capsule. The random blood glucose level and glucose tolerance function of the recipient mice in two groups were continuously monitored after operation. Islet grafts of the surviving recipient mice were harvested at postoperative 100 d for histopathological examination. Results In the white adipose group, the blood glucose levels of 6 recipient mice were restored to normal at 1 month after transplantation, whereas the blood glucose levels of the other 4 recipient mice were high, which died before the end of monitoring. In the renal capsule group, the blood glucose levels of 10 recipient mice returned to normal within 10 d after transplantation. Islet grafts of the recipient mice in two groups could lower the blood glucose levels, whereas the islet grafts in the white adipose group required a longer time to exert the effect. The glucose tolerance function of the mice in the renal capsule group was significantly better than that of those in white adipose group (P < 0.05). Histopathological examination demonstrated that the insulin of the islet grafts was normally expressed in two groups. Conclusions The islets transplanted into the subcutaneous white adipose tissues of inguinal region can play an effective role in regulating the changes of blood glucose level. Although the blood glucose-lowering function is slightly weaker than that of the islets graft in the renal capsule, it has multiple advantages resembling the ideal islet transplantation sites, which is a promising replacement site for islet transplantation.

Cordycepin promotes browning of white adipose tissue through an AMP-activated protein kinase (AMPK)-dependent pathway

Obesity is a worldwide epidemic. Promoting browning of white adipose tissue (WAT) contributes to increased energy expenditure and hence counteracts obesity. Here we show that cordycepin (Cpn), a natural derivative of adenosine, increases energy expenditure, inhibits weight gain, improves metabolic profile and glucose tolerance, decreases WAT mass and adipocyte size, and enhances cold tolerance in normal and high-fat diet-fed mice. Cpn markedly increases the surface temperature around the inguinal WAT and turns the inguinal fat browner. Further investigations show that Cpn induces the development of brown-like adipocytes in inguinal and, to a less degree, epididymal WAT depots. Cpn also increases the expression of uncoupling protein 1 (UCP1) and other thermogenic genes in WAT and 3T3-L1 differentiated adipocytes, in which AMP-activated protein kinase (AMPK) plays an important role. Our results provide novel insights into the function of Cpn in regulating energy balance, and suggest a potential utility of Cpn in the treatment of obesity.

Effect of cold exposure on browning of white adipose tissues in mice fed with high fat diet / 中国药理学通报

Aim: To observe the effect of cold exposure on browning of white adipose tissues in mice fed with high fat diet. Methods: Male 8-week-old C57BL/6J mice were randomly divided into HFD + 5 °C group and HFD + RT group, after 8 weeks of high-fat diet. Male 8-week-old C57BL/6J mice were randomly divided into normal + 5 °C group and normal + RT group, after 8 weeks of normal diet. Each group of mice were intervened for 2 h at different temperatures in the same time period for 8 weeks. Parameters, including body weight, food intake, inguinal white adipose tissue (iWAT) mass, brown adipose tissue (BAT) mass, blood glucose, blood lipids, leptin, adiponectin, adipose tissue pathology and in situ expression of uncoupling protein 1(UCP1) and prohibitin protein (PHB) in iWAT and BAT. Results: Compared with HFD + RT group, cold exposure not only significantly reduced body weight, blood glucose, iWAT weight/body weight ratio, TC, TG, LDL-C and leptin, but also increased food intake and BAT weight in high-fat diet mice. HE staining showed that iWAT and BAT cells became smaller and had multiple compartments. The iWAT had a browning trend. Immunohistochemistry showed that UCP1 and PHB protein in iWAT and BAT significantly increased. Conclusions: Cold exposure can counteract the weight gain caused by a high-fat diet, which may be related to the activation of brown adipose tissue and the induction of browning of white adipose tissues, increasing heat production and reducing white fat accumulation.

Electroacupuncture Relieves Obesity by Up-regulating PGC-1 α/UCP-1 Signaling in White Adipose Tissue in Diet-induced Obesity Rats / 针刺研究

OBJECTIVE: To observe the effect of electroacupuncture (EA) on the activities of peroxisome proliferator-activated receptor gamma coactivator-1 alpha/uncoupling protein-1 (PGC-1 α/UCP-1) signaling pathway in white adipose tissue(WAT)of diet-induced obesity (DIO) rats, so as to reveal its underlying mechanism in body weight loss. METHODS: Thirty-four male Wistar rats were randomly divided into normal diet (control, n＝10), high fat diet (model), sham EA-acupoint and EA groups (n＝8 in each of the latter 3 groups). The obesity model was established by feeding the rats with high fat diet containing lard oil, sugar, albumen powder, cholesterol, salt and sodium cholate for 12 weeks. EA (2 Hz/15 Hz, 1 mA) was applied to bilateral "Zusanli" (ST 36) and "Tianshu" (ST 25) or sham acupoints (about 5 mm beside ST 36 and ST 25) for 30 min, once daily, 5 times per week for a total of 8 weeks. During the treatment, all rats were fed with normal diet, and their body weight and length were measured once a week for calculating the Lee's index. The contents of serum total cholesterol (TC) and triglyceride (TG) were measured by using biochemical methods. The immunoactivity of PGC-1 α and UCP-1 in the abdominal WAT was detected by immunohistochemistry. RESULTS: After modeling, the Lee's index, serum TC and TG contents were significantly increased, and the levels of serum HDL-C, and PGC-1 α and UCP-1 immunoactivity in WAT considerably decreased in the model group relevant to the control group (P<0.05). Following the treatment, the Lee's index, TC and TG contents were significantly down-regulated while HDL-C and PGC-1 α and UCP-1 immunoactivity were obviously up-regulated in the EA-acupoint group relevant to the model group (P<0.05). CONCLUSION: EA can effectively reduce the body weight and adipose content in obesity rats, which may be closely related to its effect in up-regulating PGC-1 α/UCP-1 signaling in WAT, suggesting an efficacy of EA in promoting the browning of WAT.

Electroacupuncture Reduces Body Fat by Down-regulating IL-6 and Vimentin in Abdominal White Adipose Tissue of Diet-induced Obesity Rats / 针刺研究

OBJECTIVE: To investigate the effect of electroacupuncture (EA) on IL-6 and vimentin protein expression in white adipose tissue (WAT) of diet-induced obesity (DIO) rats, so as to reveal its mechanism underlying losing weight. METHODS: Thirty-four Wistar rats were randomly divided into normal (control, n＝10), model, sham-EA and EA groups (n＝8 in each of the latter 3 groups). The obesity model was established by feeding the rats with high fat diet. EA (2 Hz/15 Hz, 1 mA) was applied to bilate-ral "Zusanli "(ST 36) and "Tianshu "(ST 25) for 30 min, 5 times per week for a total of 8 weeks. For sham-EA group, two sham points (about 5 mm lateral to ST 36 and to ST 25) were only punctured with filiform needles but without electrical stimulation. Du-ring EA treatment, all rats were fed with normal fodder, and their body weight were measured once a week. Histopathologic changes (diameters of adipose cells) of abdominal WAT were observed under microscope after sectioning and H．E. staining, and the expression levels of IL-6 and vimentin in the WAT were detected by Western blot. RESULTS: Compared with the control group, the body weight, diameter of fat cells and the expression levels of IL-6 and vimentin in the WAT were significantly increased in the model group (P0.05)．. CONCLUSION: EA intervention can effectively down-regulate the expression of IL-6 and vimentin in WAT of DIO rats, which may contribute to its action in reducing body fat by relieving chronic inflammation.

Bone marrow adipose tissue——A kind of special adipose tissue / 中华内分泌代谢杂志

Bone marrow adipose tissue (MAT) is formed by the accumulation of adipocytes in the bone marrow cavity. Previously, the function of MAT is mainly considered to be filled with bone marrow cavity for the mechanical support. However,with the in-depth study of MAT,it has been gradually understood that MAT is not only a part of the bone marrow microenvironment,may also be a new endocrine "organ". The main component of bone marrow adipocytes(BMA) plays a regulatory role in bone marrow and systemic metabolism through the autocrine and paracrine secretion of adiponectin, leptin, interleukin-6, and a series of cytokines. Though its biological characteristics are somewhat similar with white fat adipose tissue(WAT) and brown adipose tissue(BAT),there are some significant differences,so MAT is thought to be a special adipose tissue. MAT is also involved in the development of hematological diseases,metabolic diseases,degenerative diseases,and may affect their outcomes. MAT may be the auxiliary diagnostic criteria and treatment targets of such diseases. This article will review the MAT's own biological characteristics,the differences and associations among three types of adipose tissue and the link between MAT and the diseases,which aims to explore the new research direction through the profound understanding of MAT.

Research of mechanisms of liraglutide inducing expression of fibroblast growth factor 21 in white adipose tissues of obese type 2 diabetic rats / 中国药理学通报

Aim To investigate the effect of liraglutide on expression of fibroblast growth factor 21 in white ad-ipose tissues and its mechanisms. Methods Male SD rats were subjected to a standard control diet or high-fat diet ( HFD) for 12 weeks, then the HFD group was in-jected introperitoneally with 30 mg · kg-1 streptozoto-cin to induce type 2 diabetes mellitus model. Half number of rats of type 2 diabetes mellitus were injected with liraglutide ( DM +LRG, 0. 4 mg · kg-1 · d-1 , two times one day ) for another 6 weeks. Serum bio-chemical indices and FGF21 levels were detected. The pathological changes in epididymal adipose tissues were detected by HE staining. The mRNA and protein ex-pression and phosphorylation of FGF21 , peroxisome proliferator-activated receptor γ ( PPARγ) , fibroblast growth factor receptor 3 (FGFR3),β-Klotho, liver ki-nase B1(LKB1), AMP-activated kinase (AMPK), a-cetyl-CoA carboxylase ( ACC ) and phosphorylation of signaling molecules in MAPK pathway were assessed by RT-PCR, immunohistochemistry and Western blot re-spectively. Results Body mass and serum lipid, ALT and AST levels increased in DM group, while FGF21 level decreased, and the volume of adipose cells in ep-ididymal adipose tissues was expanded. Expressions of FGF21, PPARγ, p-FGFR3, β-Klotho, p-LKB1, p-AMPK, p-ACC were down-regulated, while p-ERK, p-JNK and p-p38 expression were all increased. These indices were reverted by liraglutide treatment. Conclu-sion Liraglutide has significant lipid-lowering effect, which maybe related with increased FGF21 expression, activating AMPK pathway and inhibiting MAPK path-way.

Effects and mechanism of epigallocatechin gallate on white adipose tissue angiogenesis in high fat diet rats / 中华临床营养杂志

Objective To investigate the effects and mechanism of (-)-epigallocatechin-3-gallate (EGCG) on white adipose tissue angiogenesis in high fat diet rats.Methods Twenty-four male weaning SD rats were randomly divided into normal control group,high fat diet group and EGCG intervention group,8 rats in each group.Normal control group were fed with normal diet,high-fat diet group were fed with high-fat diet,EGCG intervention group were fed with high-fat diet along with intragastric administration of 200 mg/ (kg · d) EGCG.After 8 weeks,the rats were sacrificed.The adipocyte size and vascular density of the abdominal adipose tissue in rats in each group were observed under the microscope.The serum vascular endothelial growth factor (VEGF) concentration was detected by Elisa Kit.RT-PCR was used to detect the expression of VEGF,nuclear factor E2 (Nrf2),heme oxygenase-1 (HO-1),catalase (CAT),SOD,GPx,interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) mRNA.Results The adipocyte size,number of vascular/each adipocyte,serum VEGF concentration and VEGF mRNA expression in adipose tissue of high fat diet group were significantly higher than those of normal control group (all P＜0.05).EGCG can significantly reduce the above indicators of high fat diet group (all P＜0.05).The expression of Nrf2,HO-1,SOD,GPx and CAT mRNA in adipose tissue of EGCG group was significantly higher than those in high fat diet group and normal control group (all P＜0.05).The expression of MCP-1 and IL-6 mRNA in adipose tissue of EGCG group was significantly lower than that in high fat diet group (all P＜0.05).Conclusion EGCG can decrease the production of serum VEGF,vascular density and the expression of VEGF mRNA in white adipose tissue of high fat diet rats,and inhibit the angiogenesis in white adipose tissue possibly due to its up-regulation of Nrf2/HO-1 pathway to increase the expression of antioxidant enzymes (SOD,CAT,GPx),reduce ROS production and decrease the inflammatory response.

Application limitations of sympathetic nerve-mediated thermogenesis of brown/ beige adipose tissue in the treatment of obesity / 中华内分泌代谢杂志

Studies on promoting thermogenesis of brown and beige adipose tissue have become a hot topic in various metabolic conditions, which based on the conclusions that brown and beige adipose tissue are able to facilitate weight loss and improve metabolic health.However, recent studies showed that there were several problems for the anti-obesity application via promoting brown/beige adipose tissue thermogenesis.In obese individuals, classical brown adipose tissue presents thermogenesis dysfunction.Moreover, the beige adipose tissue has significantly lower thermogenesis capability compared with brown adipose tissue.On such conditions, excessively excited sympathetic innervation is essential to increase energy consumption in obesity via increasing classic brown adipose thermogenesis and inducing white adipose tissue browning.However, excessive excited sympathetic nerve results in cardiovascular side effects.Additionally, excessive induction of white adipose tissue browning might disrupt the white adipose tissue homeostasis and aggravate the intrinsic metabolic disorders.Therefore, solving these practical application problems of brown/beige adipose tissue is a new research area for improving metabolic disorders.

Role of type II innate lymphoid cells in browning of white adipose tissue / 中国病理生理杂志

Type II innate lymphoid cells ( ILC2s) are widely distributed in the blood , intestines, trachea, lung, spleen, liver, animal fat and skin, and involved in the innate immune responses .ILC2s have attracted much atten-tion for its important roles in the conversion of white adipose to beige adipose .Studies have shown that ILC2s are essential for the proliferation and differentiation of adipocyte precursor cells , and they also play a vital role in anti-parasitic infection and allergic inflammation .This review discusses the discovery , differentiation , development , distribution and function of ILC2s, and their relationships with the browning of white adipose tissue for providing valuable references on understanding the pathogenesis , prevention and treatment of obesity and fat metabolism disorders .

Efeitos da suplementação crônica com leucina sobre parâmetros metabólicos associados à adiposidade do tecido adiposo branco em ratos com diabetes induzido por estreptozotocina no período neonatal / Effects of chronic supplementation with leucine on metabolic parameters associated with the adiposity of white adipose tissue in rats with diabetes streptozotocin-induced in the neonatal period

A hiperglicemia crônica no diabetes está relacionada com distúrbios nas vias de sinalização da insulina e do mTOR, e com o desbalanço na secreção de adipocinas pelo tecido adiposo branco (TAB). Em longo prazo, esta disfunção metabólica pode causar uma perda severa de massa adiposa, o que agrava a resistência à insulina (RI). Estudos têm destacado o potencial efeito da suplementação com leucina no tratamento de doenças metabólicas como o diabetes tipo 2 e obesidade. No entanto, os efeitos da leucina sobre a homeostase glicêmica e a sensibilidade à insulina em doenças em que ocorre perda severa de gordura ainda necessitam melhores esclarecimentos. Portanto, foi investigado se a suplementação crônica com leucina pode afetar a adiposidade de ratos diabéticos com perda intensa de TAB, e melhorar a RI e outras desordens metabólicas relacionadas com TAB. Ratos recém-desmamados foram distribuídos em 3 grupos: i) Grupo controle (C) - não diabético e recebiam ração controle; ii) Grupo diabetes (D) - diabético e recebiam ração controle; iii) Grupo diabetes Leucina (DL) - diabético e recebiam ração suplementada com 5% de L-leucina. Após 8 semanas, foram analisados: glicemia e insulinemia de jejum, HOMAIR, citocinas pro- e anti-inflamatórias no soro e tecido adiposo branco, expressão de proteínas (mTOR, p-MTOR, p70S6K1, p-p70S6K1, PPARγ, C/EBPα, ACC1, FAS, AKT, p-AKT) nos tecidos adiposos subcutâneo (SC) e retroperitoneal (RP), bem como a expressão de RNAm da adiponectina e leptina no TAB. In vivo, foram realizados testes de tolerância oral à glicose (OGTT) e de sensibilidade à insulina (ITT), glicemia pós prandial e consumo de ração. O tratamento crônico com leucina reverteu a perda de massa adiposa dos coxins subcutâneo e viscerais neste modelo experimental, o que pode ser explicado pelo aumento da expressão da p-p70S6K1, PPARγ, ACC1 e FAS, proteínas que estimulam a adipogênese e lipogênese de novo nos adipócitos. Além disso, houve um aumento da expressão de AKT total no coxim SC no grupo DL, mas não foi alterada no coxim RP, indicando que a leucina também pode melhorar a resistência à insulina por ativar a AKT, que é considerada enzima limitante da cascata de fosforilação da insulina. Por outro lado, a leucina melhorou o perfil de adipocinas secretadas pelo coxim RP, pois aumentou a secreção de adiponectina e IL-10. Estas citocinas, direta ou indiretamente, reduzem a RI em tecidos como fígado, TAB e músculo esquelético. Isto sugere que a ação da leucina sobre a sensibilidade à insulina no coxim subcutâneo parece estar mais relacionada com a recuperação da via de sinalização da insulina, ao passo que, no coxim RP está indiretamente relacionada com a melhora do perfil de adipocinas secretadas por este tecido. Estes dados corroboram com os resultados de HOMAIR, glicemia de jejum e pós prandial, OGTT e ITT, nos quais foi observada uma significativa melhora do quadro de intolerância à glicose e resistência à insulina em ratos diabéticos tratados com leucina. Em conclusão, a suplementação crônica com leucina aumentou a adiposidade corporal em ratos diabéticos induzido por estreptozotocina no período neonatal, o que foi relacionado com a melhora da intolerância à glicose e da resistência à insulina. Isto demonstra que a recuperação trófica do tecido adiposo branco é fundamental para a melhora dos distúrbios metabólicos relacionados ao metabolismo da glicose neste modelo experimental

The chronic hyperglycemia in diabetes is associated with disturbances in insulin and in mTOR pathways, and changes in adipokine secretion in white adipose tissue (WAT). Long-term, this metabolic dysfunction can cause a severe loss of fat mass, which increases insulin resistance (IR). Studies have highlighted the effect of leucine supplementation in treatment of metabolic diseases as type 2 diabetes and obesity. However, the effects of leucine on glucose homeostasis and insulin sensitivity in diseases with intense fat loss remain unknown. Therefore, was investigated whether chronic leucine supplementation can affect the adiposity of diabetic rats with severe adipose tissue loss, and to improve the IR and other metabolic disorders associated with WAT. After weaning, rats were distributed in 3 groups: i) control group (C) - no diabetic and received control chow ; ii) diabetes group (D) - diabetic and received control chow; iii) Leucine Diabetes Group (DL) - diabetic and received diet supplemented with 5% L-leucine. After 8 weeks, were analyzed: fasting glycaemia and insulin, HOMA>IR, antiinflammatory and proinflammatory cytokines in serum and in WAT, protein expression of mTOR, p-MTOR, p70S6K1, p-p70S6K1, PPARγ, C/EBPα, ACC1, FAS, AKT, p-AKT in subcutaneous (SC) and retroperitoneal adipose tissue, as well as the RNAm expression of adiponectin and leptin in WAT. In vivo, were realized oral glucose tolerance test (OGTT) and insulin sensitivity test (ITT), postprandial glycaemia and chow ingestion. O chronic treatment with leucine recovered the adipose mass in subcutaneous and visceral fat pad in this experimental model, this was explicated by increase of protein expression of p-p70S6K1, PPARγ, ACC1 and FAS that stimulate the adipogenesis and de novo lipogenesis in adipocytes. Moreover, had an increase of protein expression of total AkT in subcutaneous fat pad in group DL, but don't change in RP fat pad, indicating that the leucine can to activate the AKT, which is limiting enzyme of phosphorylation cascade of insulin, and improve the insulin resistance. On the other hand, leucine improved the profile of adipokines secreted in RP fat pad, because increased the secretion of adiponectin and IL-10. This cytokines reduced the insulin resistance in tissues as liver, WAT and skeletal muscle. This suggest that action of leucine on insulin sensitivity in subcutaneous fat pad is more related to recovery of insulin signaling, and in RP fat pad is indirectly related to improve of profile of adipokines secretion in this tissue. This data corroborates with results of HOMAIR, postprandial and fasting glycaemia, OGTT and ITT, which showed significant improve of glucose intolerance and insulin resistance in diabetic rats treated with leucine. In conclusion, the chronic leucine supplementation increased adiposity in streptozotocin-induced diabetic rats in neonatal period, which was related to improve of glucose intolerance and insulin resistance. This show that trophic recovery of white adipose tissue is important for improve of metabolic disturbances related to glucose metabolism in this experimental model