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Hao L, Khan MSH, Zu Y, Liu J, Wang S. Thermoneutrality Inhibits Thermogenic Markers and Exacerbates Nonalcoholic Fatty Liver Disease in Mice. Int J Mol Sci 2024; 25:8482. [PMID: 39126051 PMCID: PMC11312964 DOI: 10.3390/ijms25158482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2024] [Revised: 07/30/2024] [Accepted: 08/01/2024] [Indexed: 08/12/2024] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) affects over a third of the US population and 25% globally, with current treatments proving ineffective. This study investigates whether manipulating brown adipose tissue (BAT) and beige fat activity by housing C57BL/6J mice at thermoneutral (27 °C) or standard temperatures (22 °C) impacts NAFLD development. Male mice were fed either a chow diet (CHD) or a "fast food" diet (FFD) for 10 weeks. Mice at 27 °C had reduced food intake but increased body weight and plasma leptin levels. FFD-fed mice at 27 °C had greater liver weight (2.6 vs. 1.8 g), triglyceride content (7.6 vs. 3.9 mg/g), and hepatic steatosis compared to those at 22 °C. Gene expression of fatty acid synthase, sterol regulatory element-binding protein 1, and fatty acid translocase CD36 was elevated in FFD-fed mice at 27 °C, but not in CHD-fed mice. Thermoneutral housing also reduced expression of thermogenic markers in BAT and inguinal white adipose tissue (WAT) and caused BAT whitening. In conclusion, thermoneutrality inhibits thermogenic markers and exacerbates NAFLD. Activating BAT or promoting WAT browning via cold exposure or other stimuli may offer a strategy for managing NAFLD.
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Affiliation(s)
- Lei Hao
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX 79409, USA; (M.S.H.K.); (Y.Z.); (J.L.)
- Department of Allied and Public Health, Indiana University of Pennsylvania, Indian, PA 15705, USA
| | - Md Shahjalal Hossain Khan
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX 79409, USA; (M.S.H.K.); (Y.Z.); (J.L.)
| | - Yujiao Zu
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX 79409, USA; (M.S.H.K.); (Y.Z.); (J.L.)
| | - Jie Liu
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX 79409, USA; (M.S.H.K.); (Y.Z.); (J.L.)
| | - Shu Wang
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX 79409, USA; (M.S.H.K.); (Y.Z.); (J.L.)
- College of Health Solutions, Arizona State University, Phoenix, AZ 85004, USA
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Jia Y, Liu Y, Liu S, Chang Y, Xu L, Li H. Wnt10b knockdown promotes UCP1 expression in brown adipose tissue in mice. Genes Cells 2023; 28:764-775. [PMID: 37691290 DOI: 10.1111/gtc.13064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 08/15/2023] [Accepted: 08/23/2023] [Indexed: 09/12/2023]
Abstract
The effect of Wnt10b overexpression on adipose tissue development has been reported. However, the impact of Wnt10b knockdown on the function of brown adipose tissue (BAT) is yet largely unknown. Here, we used the CRISPR/Cas9 technique to generate Wnt10b-knockdown (Wnt10b+/- ) mice. We compared the development and thermogenic gene expression of interscapular BAT (iBAT) between Wnt10b+/- and Wnt10b+/+ mice under a chow diet, high-fat diet (HFD), and cold exposure conditions. Moreover, the effect of Wnt10b knockdown on brown adipocyte function was tested via in vitro experiments. Results indicated that Wnt10b knockdown decreased the iBAT mass and the brown adipocyte size and enhanced thermogenic gene expression, including UCP1, under chow diet conditions. In addition, Wnt10b+/- mice appeared to be able to maintain their body temperature better than the control in a cold environment, accompanied by higher UCP1 protein expression. Intriguingly, even under HFD conditions, Wnt10b+/- mice still showed higher UCP1 expression, which was associated with an alleviated obesity phenotype. In vitro studies further evidenced the Wnt10b knockdown stimulation of UCP1 expression and suppression of the adipogenic program. This study indicates that Wnt10b knockdown enhances UCP1 expression and inhibits the adipogenic differentiation of brown adipocytes, providing a novel option for therapeutic interventions in adiposity.
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Affiliation(s)
- Yanxin Jia
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Yan Liu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Shuang Liu
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an, China
| | - Yaxin Chang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Longfei Xu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Haifang Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
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Pal SC, Méndez-Sánchez N. Insulin resistance and adipose tissue interactions as the cornerstone of metabolic (dysfunction)-associated fatty liver disease pathogenesis. World J Gastroenterol 2023; 29:3999-4008. [PMID: 37476582 PMCID: PMC10354585 DOI: 10.3748/wjg.v29.i25.3999] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/09/2023] [Accepted: 03/20/2023] [Indexed: 06/28/2023] Open
Abstract
The relationship between metabolic derangements and fatty liver development are undeniable, since more than 75% of patients with type 2 diabetes mellitus present with fatty liver. There is also significant epidemiological association between insulin resistance (IR) and metabolic (dysfunction)-associated fatty liver disease (MAFLD). For little more than 2 years, the nomenclature of fatty liver of non-alcoholic origin has been intended to change to MAFLD by multiple groups. While a myriad of reasons for which MAFLD is thought to be of metabolic origin could be exposed, the bottom line relies on the role of IR as an initiator and perpetuator of this disease. There is a reciprocal role in MAFLD development and IR as well as serum glucose concentrations, where increased circulating glucose and insulin result in increased de novo lipogenesis by sterol regulatory element-binding protein-1c induced lipogenic enzyme stimulation; therefore, increased endogenous production of triglycerides. The same effect is achieved through impaired suppression of adipose tissue (AT) lipolysis in insulin-resistant states, increasing fatty acid influx into the liver. The complementary reciprocal situation occurs when liver steatosis alters hepatokine secretion, modifying fatty acid metabolism as well as IR in a variety of tissues, including skeletal muscle, AT, and the liver. The aim of this review is to discuss the importance of IR and AT interactions in metabolic altered states as perhaps the most important factor in MAFLD pathogenesis.
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Affiliation(s)
- Shreya C Pal
- Faculty of Medicine, National Autonomous University of Mexico, Mexico City 04510, Mexico
- Liver Research Unit, Medica Sur Clinic & Foundation, Mexico City 04510, Mexico
| | - Nahum Méndez-Sánchez
- Faculty of Medicine, National Autonomous University of Mexico, Mexico City 04510, Mexico
- Liver Research Unit, Medica Sur Clinic & Foundation, Mexico City 04510, Mexico
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Gavaldà-Navarro A, Villarroya J, Cereijo R, Giralt M, Villarroya F. The endocrine role of brown adipose tissue: An update on actors and actions. Rev Endocr Metab Disord 2022; 23:31-41. [PMID: 33712997 DOI: 10.1007/s11154-021-09640-6] [Citation(s) in RCA: 75] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/26/2021] [Indexed: 02/06/2023]
Abstract
In recent years, brown adipose tissue (BAT) has been recognized not only as a main site of non-shivering thermogenesis in mammals, but also as an endocrine organ. BAT secretes a myriad of regulatory factors. These so-called batokines exert local autocrine and paracrine effects, as well as endocrine actions targeting tissues and organs at a distance. The endocrine batokines include peptide factors, such as fibroblast growth factor-21 (FGF21), neuregulin-4 (NRG4), phospholipid transfer protein (PLTP), interleukin-6, adiponectin and myostatin, and also lipids (lipokines; e.g., 12,13-dihydroxy-9Z-octadecenoic acid [12,13-diHOME]) and miRNAs (e.g., miR-99b). The liver, heart, and skeletal muscle are the most commonly reported targets of batokines. In response to BAT thermogenic activation, batokines such as NRG4 and PLTP are released and act to reduce hepatic steatosis and improve insulin sensitivity. Stress-induced interleukin-6-mediated signaling from BAT to liver favors hepatic glucose production through enhanced gluconeogenesis. Batokines may act on liver to induce the secretion of regulatory hepatokines (e.g. FGF21 and bile acids in response to miR-99b and PLTP, respectively), thereby resulting in a systemic expansion of BAT-originating signals. Batokines also target extrahepatic tissues: FGF21 and 12,13-diHOME are cardioprotective, whereas BAT-secreted myostatin and 12,13-diHOME influence skeletal muscle development and performance. Further research is needed to ascertain in humans the role of batokines, which have been identified mostly in experimental models. The endocrine role of BAT may explain the association between active BAT and a healthy metabolism in the human system, which is characterized by small amounts of BAT and a likely moderate BAT-mediated energy expenditure.
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Affiliation(s)
- Aleix Gavaldà-Navarro
- Departament de Bioquimica I Biomedicina Molecular, and Institut de Biomedicina de La Universitat de Barcelona, Barcelona, Catalonia, Spain
- Institut de Recerca Sant Joan de Déu, Esplugues, Catalonia, Spain
- CIBER Fisiopatología de La Obesidad Y Nutrición, Madrid, Spain
| | - Joan Villarroya
- Departament de Bioquimica I Biomedicina Molecular, and Institut de Biomedicina de La Universitat de Barcelona, Barcelona, Catalonia, Spain
- Institut de Recerca Sant Joan de Déu, Esplugues, Catalonia, Spain
- CIBER Fisiopatología de La Obesidad Y Nutrición, Madrid, Spain
| | - Rubén Cereijo
- Departament de Bioquimica I Biomedicina Molecular, and Institut de Biomedicina de La Universitat de Barcelona, Barcelona, Catalonia, Spain
- CIBER Fisiopatología de La Obesidad Y Nutrición, Madrid, Spain
- Institut de Recerca Hospital de La Santa Creu I Sant Pau, Barcelona, Spain
| | - Marta Giralt
- Departament de Bioquimica I Biomedicina Molecular, and Institut de Biomedicina de La Universitat de Barcelona, Barcelona, Catalonia, Spain
- Institut de Recerca Sant Joan de Déu, Esplugues, Catalonia, Spain
- CIBER Fisiopatología de La Obesidad Y Nutrición, Madrid, Spain
| | - Francesc Villarroya
- Departament de Bioquimica I Biomedicina Molecular, and Institut de Biomedicina de La Universitat de Barcelona, Barcelona, Catalonia, Spain.
- Institut de Recerca Sant Joan de Déu, Esplugues, Catalonia, Spain.
- CIBER Fisiopatología de La Obesidad Y Nutrición, Madrid, Spain.
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Herz CT, Kulterer OC, Prager M, Schmöltzer C, Langer FB, Prager G, Marculescu R, Kautzky-Willer A, Hacker M, Haug AR, Kiefer FW. Active Brown Adipose Tissue is Associated With a Healthier Metabolic Phenotype in Obesity. Diabetes 2021; 71:db210475. [PMID: 34957487 DOI: 10.2337/db21-0475] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 10/13/2021] [Indexed: 11/13/2022]
Abstract
Obesity is associated with increasing cardiometabolic morbidity and mortality worldwide. Not everyone with obesity, however, develops metabolic complications. Brown adipose tissue (BAT) has been suggested as a promoter of leanness and metabolic health. To date, little is known about the prevalence and metabolic function of BAT in subjects with severe obesity, a population at high cardiometabolic risk. In this cross-sectional study, we included 40 individuals with WHO class II-III obesity (BMI ≥ 35 kg/m2). Employing a 150-minute personalized cooling protocol and 18F-fluorodeoxyglucose positron emission tomography/computed tomography, cold-activated BAT was detectable in 14 (35%) of the participants. Cold-induced thermogenesis was significantly higher in participants with detectable BAT compared to those without. Notably, individuals with obesity and active BAT had 28.8% lower visceral fat mass despite slightly higher total fat mass compared to those without detectable BAT 18F-FDG uptake. This was accompanied by lower insulin resistance and systemic inflammation and improved NAFLD parameters, all adjusted for age, sex, and percent body fat. Contrary to previous assumptions, we show here that a significant fraction of individuals with severe obesity has active BAT. We found that decreased BAT 18F-FDG uptake was not associated with adiposity per se but with higher visceral fat mass. In summary, active BAT is linked to a healthier metabolic phenotype in obesity.
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Affiliation(s)
- Carsten T Herz
- Division of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Oana C Kulterer
- Division of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Marlene Prager
- Division of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Christoph Schmöltzer
- Division of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Felix B Langer
- Division of General Surgery, Department of Surgery, Medical University of Vienna, Vienna, Austria
| | - Gerhard Prager
- Division of General Surgery, Department of Surgery, Medical University of Vienna, Vienna, Austria
| | - Rodrig Marculescu
- Division of Medical-Chemical Laboratory Diagnostics, Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Alexandra Kautzky-Willer
- Division of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Marcus Hacker
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Alexander R Haug
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Florian W Kiefer
- Division of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
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Tutunchi H, Mobasseri M, Aghamohammadzadeh N, Hooshyar J, Naeini F, Najafipour F. Serum neuregulin 4 (NRG-4) level and non-alcoholic fatty liver disease (NAFLD): A case-control study. Int J Clin Pract 2021; 75:e14555. [PMID: 34159710 DOI: 10.1111/ijcp.14555] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/21/2021] [Indexed: 11/30/2022] Open
Abstract
OBJECTIVE The current case-control study aimed to examine the association of circulating neuregulin 4 (NRG-4), a brown fat-enriched endocrine factor, with non-alcoholic fatty liver disease (NAFLD). METHODS A total of 50 patients newly diagnosed with NAFLD with 50 age-matched and sex-matched subjects without NAFLD were recruited in the present study. Circulating NRG-4 levels were assessed with an enzyme-linked immunosorbent assay (ELISA) kit. SPSS version 23 was used for statistical analysis. RESULTS Patients with NAFLD had lower levels of circulating NRG-4 than the control group (P < .001). Participants in the highest quartile of circulating NRG-4 had significantly lower body mass index (BMI), waist circumference (WC), triglyceride (TG) and homeostatic model assessment for insulin resistance (HOMA-IR) compared with those in the lowest quartile (all P < .01). The prevalence of NAFLD in the quartile 4 of the serum NRG-4 level was 38.46%, lower than the quartile 1 (62.50%, P = .006), quartile 2 (52.00%, P = .017) and quartile 3 (48.00%, P = .032). In multiple stepwise regression analysis, BMI (β = -0.712, P = .016), WC (β = -0.577, P = .023), TG (β = -0.509, P = .001), high-density lipoprotein cholesterol (HDL-C) (β = 0.489, P = .001) and HOMA-IR (β = -0.609, P = .003) were independently related to serum NRG-4 level. The odds of NAFLD decreased by 41% per 1 SD increase in serum NRG-4 level (OR, 0.59; 95% CI, 0.35-0.78; P = .021), after adjustment for all potential confounders. CONCLUSION The results of the present study demonstrate that circulating NRG-4 levels may play a protective role in NAFLD.
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Affiliation(s)
- Helda Tutunchi
- Endocrine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Nutrition Research Center, Department of Clinical Nutrition, School of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Majid Mobasseri
- Endocrine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Jalil Hooshyar
- Endocrine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Fatemeh Naeini
- Department of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Science, Tehran, Iran
| | - Farzad Najafipour
- Endocrine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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7
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Tint MT, Michael N, Sadananthan SA, Huang JY, Khoo CM, Godfrey KM, Shek LPC, Lek N, Tan KH, Yap F, Velan SS, Gluckman PD, Chong YS, Karnani N, Chan SY, Leow MKS, Lee KJ, Lee YS, Hu HH, Zhang C, Fortier MV, Eriksson JG. Brown Adipose Tissue, Adiposity, and Metabolic Profile in Preschool Children. J Clin Endocrinol Metab 2021; 106:2901-2914. [PMID: 34143868 PMCID: PMC8475202 DOI: 10.1210/clinem/dgab447] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Indexed: 02/08/2023]
Abstract
CONTEXT An inverse relationship between brown adipose tissue (BAT) and obesity has previously been reported in older children and adults but is unknown in young children. OBJECTIVE We investigated the influence of BAT in thermoneutral condition on adiposity and metabolic profile in Asian preschool children. DESIGN, SETTING, AND PARTICIPANTS A total of 198 children aged 4.5 years from a prospective birth cohort study, Growing Up in Singapore Towards Healthy Outcomes (GUSTO) were successfully studied with water-fat magnetic resonance imaging of the supraclavicular and axillary fat depot (FDSA). Regions within FDSA with fat-signal-fraction between 20% and 80% were considered BAT, and percentage BAT (%BAT; 100*BAT volume/ FDSA volume) was calculated. MAIN OUTCOME MEASURES Abdominal adipose tissue compartment volumes, ectopic fat in the soleus muscle and liver, fatty liver index, metabolic syndrome scores, and markers of insulin sensitivity. RESULTS A 1% unit increase in %BAT was associated with lower body mass index, difference (95% CI), -0.08 (-0.10, -0.06) kg/m2 and smaller abdominal adipose tissue compartment volumes. Ethnicity and sex modified these associations. In addition, each unit increase in %BAT was associated with lower ectopic fat at 4.5 years in the liver, -0.008% (-0.013%, -0.003%); soleus muscle, -0.003% (-0.006%, -0.001%) of water content and lower fatty liver index at 6 years. CONCLUSIONS Higher %BAT is associated with a more favorable metabolic profile. BAT may thus play a role in the pathophysiology of obesity and related metabolic disorders. The observed ethnic and sex differences imply that the protective effect of BAT may vary among different groups.
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Affiliation(s)
- Mya Thway Tint
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore
- Department of Obstetrics & Gynecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Navin Michael
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore
| | - Suresh Anand Sadananthan
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore
| | - Jonathan Yinhao Huang
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore
| | - Chin Meng Khoo
- Division of Endocrinology, Department of Medicine, National University Health System, Singapore
| | - Keith M Godfrey
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, NHS Foundation Trust, Southampton, UK
| | - Lynette Pei-Chi Shek
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Ngee Lek
- Department of Pediatric Endocrinology, KK Women’s and Children’s Hospital, Singapore
| | - Kok Hian Tan
- Department of Obstetrics and Gynaecology, KK Women’s and Children’s Hospital, Singapore
| | - Fabian Yap
- Department of Pediatric Endocrinology, KK Women’s and Children’s Hospital, Singapore
- Duke-NUS Graduate Medical School, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - S Sendhil Velan
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore
- Singapore Bioimaging Consortium (SBIC), Agency for Science, Technology and Research (A*STAR), Singapore
| | - Peter D Gluckman
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore
- Liggins Institute, University of Auckland, Auckland, New Zealand
| | - Yap-Seng Chong
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore
- Department of Obstetrics & Gynecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Neerja Karnani
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Shiao-Yng Chan
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore
- Department of Obstetrics & Gynecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Melvin Khee-Shing Leow
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore
- Department of Endocrinology, Tan Tock Seng Hospital, Singapore
- Metabolic Disorders Research Programme, Lee Kong Chian School of Medicine, Singapore
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Medical School, Singapore
| | - Kuan Jin Lee
- Singapore Bioimaging Consortium (SBIC), Agency for Science, Technology and Research (A*STAR), Singapore
| | - Yung-Seng Lee
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Division of Paediatric Endocrinology, Department of Paediatrics, Khoo Teck Puat–National University Children’s Medical Institute, National University Health System, Singapore
| | - Houchun Harry Hu
- Department of Radiology, Nationwide Children’s Hospital, Columbus, OH, USA
| | - Cuilin Zhang
- Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD, USA
| | - Marielle V Fortier
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore
- Department of Diagnostic and Interventional Imaging, KK Women’s and Children’s Hospital, Singapore
| | - Johan G Eriksson
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore
- Department of Obstetrics & Gynecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Department of General Practice and Primary Health Care, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Folkhälsan Research Center, Helsinki, Finland
- Correspondence: Johan G. Eriksson, Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, MD1, Tahir Foundation Building, Level 12, #12-02/03, 12 Science Drive 2, Singapore 117549, Singapore. ;
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8
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Ahmed BA, Ong FJ, Barra NG, Blondin DP, Gunn E, Oreskovich SM, Szamosi JC, Syed SA, Hutchings EK, Konyer NB, Singh NP, Yabut JM, Desjardins EM, Anhê FF, Foley KP, Holloway AC, Noseworthy MD, Haman F, Carpentier AC, Surette MG, Schertzer JD, Punthakee Z, Steinberg GR, Morrison KM. Lower brown adipose tissue activity is associated with non-alcoholic fatty liver disease but not changes in the gut microbiota. Cell Rep Med 2021; 2:100397. [PMID: 34622234 PMCID: PMC8484690 DOI: 10.1016/j.xcrm.2021.100397] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 06/25/2021] [Accepted: 08/18/2021] [Indexed: 12/18/2022]
Abstract
In rodents, lower brown adipose tissue (BAT) activity is associated with greater liver steatosis and changes in the gut microbiome. However, little is known about these relationships in humans. In adults (n = 60), we assessed hepatic fat and cold-stimulated BAT activity using magnetic resonance imaging and the gut microbiota with 16S sequencing. We transplanted gnotobiotic mice with feces from humans to assess the transferability of BAT activity through the microbiota. Individuals with NAFLD (n = 29) have lower BAT activity than those without, and BAT activity is inversely related to hepatic fat content. BAT activity is not related to the characteristics of the fecal microbiota and is not transmissible through fecal transplantation to mice. Thus, low BAT activity is associated with higher hepatic fat accumulation in human adults, but this does not appear to have been mediated through the gut microbiota.
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Affiliation(s)
- Basma A. Ahmed
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Frank J. Ong
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Pediatrics, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Nicole G. Barra
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Denis P. Blondin
- Faculty of Medicine and Health Sciences, Department of Medicine, Division of Neurology, Centre de recherche du CHUS, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
| | - Elizabeth Gunn
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Pediatrics, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Stephan M. Oreskovich
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Pediatrics, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Jake C. Szamosi
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, ON L8S 4L8, Canada
- Farncombe Metagenomics Facility, Department of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Saad A. Syed
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Emily K. Hutchings
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Pediatrics, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Norman B. Konyer
- Imaging Research Centre, St. Joseph’s Healthcare, Hamilton, ON L8N 4A6, Canada
| | - Nina P. Singh
- Department of Radiology, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Julian M. Yabut
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Eric M. Desjardins
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Fernando F. Anhê
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Kevin P. Foley
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Alison C. Holloway
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Obstetrics and Gynecology, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Michael D. Noseworthy
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Imaging Research Centre, St. Joseph’s Healthcare, Hamilton, ON L8N 4A6, Canada
- Department of Radiology, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON L8S 4L8, Canada
- School of Biomedical Engineering, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Francois Haman
- Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Andre C. Carpentier
- Division of Endocrinology, Department of Medicine, Centre de recherche du CHUS, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
| | - Michael G. Surette
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Jonathan D. Schertzer
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Zubin Punthakee
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Pediatrics, McMaster University, Hamilton, ON L8S 4L8, Canada
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Gregory R. Steinberg
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Katherine M. Morrison
- Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Pediatrics, McMaster University, Hamilton, ON L8S 4L8, Canada
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9
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Heeren J, Scheja L. Metabolic-associated fatty liver disease and lipoprotein metabolism. Mol Metab 2021; 50:101238. [PMID: 33892169 PMCID: PMC8324684 DOI: 10.1016/j.molmet.2021.101238] [Citation(s) in RCA: 223] [Impact Index Per Article: 74.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/01/2021] [Accepted: 04/15/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Non-alcoholic fatty liver disease, or as recently proposed 'metabolic-associated fatty liver disease' (MAFLD), is characterized by pathological accumulation of triglycerides and other lipids in hepatocytes. This common disease can progress from simple steatosis to steatohepatitis, and eventually end-stage liver diseases. MAFLD is closely related to disturbances in systemic energy metabolism, including insulin resistance and atherogenic dyslipidemia. SCOPE OF REVIEW The liver is the central organ in lipid metabolism by secreting very low density lipoproteins (VLDL) and, on the other hand, by internalizing fatty acids and lipoproteins. This review article discusses recent research addressing hepatic lipid synthesis, VLDL production, and lipoprotein internalization as well as the lipid exchange between adipose tissue and the liver in the context of MAFLD. MAJOR CONCLUSIONS Liver steatosis in MAFLD is triggered by excessive hepatic triglyceride synthesis utilizing fatty acids derived from white adipose tissue (WAT), de novo lipogenesis (DNL) and endocytosed remnants of triglyceride-rich lipoproteins. In consequence of high hepatic lipid content, VLDL secretion is enhanced, which is the primary cause of complex dyslipidemia typical for subjects with MAFLD. Interventions reducing VLDL secretory capacity attenuate dyslipidemia while they exacerbate MAFLD, indicating that the balance of lipid storage versus secretion in hepatocytes is a critical parameter determining disease outcome. Proof of concept studies have shown that promoting lipid storage and energy combustion in adipose tissues reduces hepatic lipid load and thus ameliorates MAFLD. Moreover, hepatocellular triglyceride synthesis from DNL and WAT-derived fatty acids can be targeted to treat MAFLD. However, more research is needed to understand how individual transporters, enzymes, and their isoforms affect steatosis and dyslipidemia in vivo, and whether these two aspects of MAFLD can be selectively treated. Processing of cholesterol-enriched lipoproteins appears less important for steatosis. It may, however, modulate inflammation and consequently MAFLD progression.
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Affiliation(s)
- Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - Ludger Scheja
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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10
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Zhang H, Dong M, Liu X. Obeticholic acid ameliorates obesity and hepatic steatosis by activating brown fat. Exp Ther Med 2021; 22:991. [PMID: 34345273 PMCID: PMC8311225 DOI: 10.3892/etm.2021.10423] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 02/09/2021] [Indexed: 12/13/2022] Open
Abstract
Obeticholic acid (OCA) is exemplified as a potent drug for treating primary biliary cirrhosis and nonalcoholic fatty liver disease by inhibiting bile acid synthesis. However, it remains unclear whether the effect of OCA is mediated by the function of brown adipose tissue (BAT). In the present study, brown adipogenesis differentiation in vitro and db/db mouse model treated with OCA were used to assess the anti-obesity function by body weight tracking, O2 consumption, food intake, physical activity, glucose tolerance tests. In addition, uncoupling protein 1 (Ucp1) protein expression in brown adipose tissue was measured by western blotting, morphometry of brown adipose tissue was analyzed by hematoxylin and eosin staining. Hepatic steatosis was detected by Oil-Red O staining and serological analysis was performed to assess the effect of OCA on hyperlipidemia. OCA treatment enhanced brown adipocyte cell differentiation and upregulated the expression of the BAT-specific gene Ucp1) in C3H10T1/2 cells in vitro. Consistent with these findings, OCA increased whole-body energy metabolism and glucose homeostasis by enhancing BAT activity in vivo, and ultimately decreased body weight gain in db/db mice. In addition, the results demonstrated that spontaneous hepatic steatosis in db/db mice was ameliorated following OCA treatment. In summary, OCA functioned as a BAT activator to help ameliorate obesity and maintain glucose homeostasis in db/db mice. The present results may provide a novel potential therapeutic approach to activate brown fat in patients with obesity and other metabolic disorders.
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Affiliation(s)
- Hanlin Zhang
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, P.R. China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Meng Dong
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, P.R. China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Xiaomeng Liu
- Institute of Neuroscience and Translational Medicine, Zhoukou Normal University, Zhoukou, Henan 466001, P.R. China
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11
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Brown adipose tissue is associated with healthier body fat distribution and metabolic benefits independent of regional adiposity. CELL REPORTS MEDICINE 2021; 2:100332. [PMID: 34337558 PMCID: PMC8324464 DOI: 10.1016/j.xcrm.2021.100332] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 03/25/2021] [Accepted: 06/08/2021] [Indexed: 12/27/2022]
Abstract
The association of brown adipose tissue (BAT) and body fat distribution and their combined effects on metabolic health in humans remains unknown. Here, we retrospectively identify individuals with and without BAT on 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) and assemble a propensity score-matched study cohort to compare body fat distribution and determine its role in mediating the benefits of brown fat. We find that BAT is associated with lower amounts of visceral adipose tissue and higher amounts of subcutaneous adipose tissue, resulting in less central obesity. In addition, BAT is independently associated with lower blood glucose and white blood cell count, improved lipids, lower prevalence of type 2 diabetes mellitus, and decreased liver fat accumulation. These observations are most prominent in individuals with central obesity. Our results support a role of BAT in protection from visceral adiposity and improved metabolic health. Brown adipose tissue is associated with more subcutaneous and less visceral fat Brown adipose tissue is associated with health independent of fat distribution Brown adipose tissue is associated with less liver fat and type 2 diabetes Brown adipose tissue is most beneficial in individuals with central obesity
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12
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Namkhah Z, Naeini F, Ostadrahimi A, Tutunchi H, Hosseinzadeh-Attar MJ. The association of the adipokine zinc-alpha2-glycoprotein with non-alcoholic fatty liver disease and related risk factors: A comprehensive systematic review. Int J Clin Pract 2021; 75:e13985. [PMID: 33404166 DOI: 10.1111/ijcp.13985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 01/03/2021] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND AIM The adipokine zinc-alpha2-glycoprotein (ZAG), a multidisciplinary protein, is involved in lipid metabolism, glucose homeostasis and energy balance. Accumulating evidence demonstrates that the expression of ZAG is mainly downregulated in obesity and obesity-related conditions. In the present study, we assessed the association of ZAG with non-alcoholic fatty liver disease (NAFLD) and the related risk factors including obesity, metabolic factors and inflammatory parameters, with emphasis on potential mechanisms underlying these associations. METHODS PRISMA guidelines were followed in this review. Systematic searches were performed using the PubMed/Medline, ScienceDirect, Scopus, EMBASE, ProQuest and Google Scholar databases, up to August 2020 for all relevant published papers. RESULTS Out of 362 records screened, 34 articles were included in the final analysis. According to the studies reviewed here, ZAG appears to exert a protective effect against NAFLD by enhancing mRNA expression levels of peroxisome proliferator-activated receptor α (PPARα) and PPARγ, promoting mRNA expression levels of the lipolysis-related genes, reducing mRNA expression levels of the lipogenesis-related genes, increasing hepatic fatty acid oxidation, ameliorating hepatic steatosis, promoting the activity of brown adipose tissue and the expression of thermogenesis-related genes, modulating energy balance and glucose homeostasis, and elevating plasma levels of healthy adipokines such as adiponectin. ZAG can also be involved in the regulation of inflammatory responses by attenuation of the expression of pro-inflammatory and pro-fibrotic mediators. CONCLUSION According to the studies reviewed here, ZAG is suggested to be a promising therapeutic target for NAFLD. However, the favourable effects of ZAG need to be confirmed in prospective cohort studies.
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Affiliation(s)
- Zahra Namkhah
- Department of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Science, Tehran, Iran
| | - Fatemeh Naeini
- Department of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Science, Tehran, Iran
| | - Alireza Ostadrahimi
- Nutrition Research Center, Department of Clinical Nutrition, School of Nutrition & Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Helda Tutunchi
- Nutrition Research Center, Department of Clinical Nutrition, School of Nutrition & Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
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13
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Gao Y, Tian R, Liu H, Xue H, Zhang R, Han S, Ji L, Huang W, Zhan J, You Y. Research progress on intervention effect and mechanism of protocatechuic acid on nonalcoholic fatty liver disease. Crit Rev Food Sci Nutr 2021; 62:9053-9075. [PMID: 34142875 DOI: 10.1080/10408398.2021.1939265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) has become a surge burden worldwide due to its high prevalence, with complicated deterioration symptoms such as liver fibrosis and cancer. No effective drugs are available for NALFD so far. The rapid growth of clinical demand has prompted the treatment of NAFLD to become a research hotspot. Protocatechuic acid (PCA) is a natural secondary metabolite commonly found in fruits, vegetables, grains, and herbal medicine. It is also the major internal metabolites of anthocyanins and other polyphenols. In the present manuscript, food sources, metabolic absorption, and efficacy of PCA were summarized while analyzing its role in improving NAFLD, as well as the mechanism involved. The results indicated that PCA could ameliorate NAFLD by regulating glucose and lipid metabolism, oxidative stress and inflammation, gut microbiota and metabolites. It was proposed for the first time that PCA might reduce NAFLD by enhancing the energy consumption of brown adipose tissue (BAT). However, the PCA administration mode and dose for NAFLD remain inconclusive. Fresh insights into the specific molecular mechanisms are required, while clinical trials are essential in the future. This review provides new targets and reasoning for the clinical application of PCA in the prevention and treatment of NAFLD.
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Affiliation(s)
- Yunxiao Gao
- College of Food Science and Nutritional Engineering, Beijing Key Laboratory of Viticulture and Enology, China Agricultural University, Beijing, China
| | - Rongrong Tian
- Department of Biomedicine, Beijing City University, Beijing, China
| | - Haiyue Liu
- College of Food Science and Nutritional Engineering, Beijing Key Laboratory of Viticulture and Enology, China Agricultural University, Beijing, China
| | - Huimin Xue
- College of Food Science and Nutritional Engineering, Beijing Key Laboratory of Viticulture and Enology, China Agricultural University, Beijing, China
| | - Ruizhe Zhang
- College of Food Science and Nutritional Engineering, Beijing Key Laboratory of Viticulture and Enology, China Agricultural University, Beijing, China
| | - Suping Han
- College of Food Science and Nutritional Engineering, Beijing Key Laboratory of Viticulture and Enology, China Agricultural University, Beijing, China
| | - Lin Ji
- College of Food Science and Nutritional Engineering, Beijing Key Laboratory of Viticulture and Enology, China Agricultural University, Beijing, China
| | - Weidong Huang
- College of Food Science and Nutritional Engineering, Beijing Key Laboratory of Viticulture and Enology, China Agricultural University, Beijing, China
| | - Jicheng Zhan
- College of Food Science and Nutritional Engineering, Beijing Key Laboratory of Viticulture and Enology, China Agricultural University, Beijing, China
| | - Yilin You
- College of Food Science and Nutritional Engineering, Beijing Key Laboratory of Viticulture and Enology, China Agricultural University, Beijing, China
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14
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Nga HT, Moon JS, Tian J, Lee HY, Kim SH, Lee YS, Jeon JH, Yi HS. Interleukin-10 Attenuates Liver Fibrosis Exacerbated by Thermoneutrality. Front Med (Lausanne) 2021; 8:672658. [PMID: 34124102 PMCID: PMC8187571 DOI: 10.3389/fmed.2021.672658] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 05/03/2021] [Indexed: 01/14/2023] Open
Abstract
Background: Crosstalk between brown adipose tissue (BAT) and the liver is receiving increasing attention. This study investigated the effect of BAT dysfunction by thermoneutral (TN) housing on liver fibrosis in mice and examined the effect of secreted factors from brown adipocytes on the activation of hepatic stellate cells (HSCs). Methods: The carbon tetrachloride (CCl4)-induced liver fibrosis mouse model was used to evaluate fibrotic changes in the livers of mice housed under standard and TN conditions. The effect of BAT on the activation of HSCs was examined using cultured cells treated with conditioned media from brown adipocytes. Results: Under TN conditions, mice with CCl4-induced liver fibrosis exhibited increased liver injury, collagen deposition, and alpha smooth muscle actin (α-SMA) expression in the liver compared with mice maintained at room temperature. The numbers of liver-infiltrating immune cells and T cells producing IL-17A and IFN-γ were also significantly increased in the livers of mice housed under TN conditions. Treatment of HSCs with conditioned media from brown adipocytes markedly attenuated HSC activation, as shown by down-regulated α-SMA expression at day 4, day 7 and day 10 of culture. At thermoneutrality, with CCl4 administration, IL-10-deficient mice exhibited more severe liver fibrosis than wild-type mice. Interestingly, conditioned media from IL-10-deficient brown adipocytes could up-regulate the expression of α-SMA and induce HSCs activation. Conclusions: BAT inactivation by thermoneutrality contributes to the activation of pro-inflammatory and pro-fibrotic pathways in mice with CCl4-induced liver fibrosis. Normal brown adipocytes secreted factors that impair the activation of HSCs, while this protective effect was lost in IL-10-deficient brown adipocytes. Thus, the BAT–liver axis may serve as a potential therapeutic target for liver fibrosis, and IL-10 may be a key factor regulating the activation of HSCs by BAT.
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Affiliation(s)
- Ha Thi Nga
- Laboratory of Endocrinology and Immune System, Chungnam National University School of Medicine, Daejeon, South Korea.,Department of Medical Science, Chungnam National University School of Medicine, Daejeon, South Korea.,Research Center for Endocrine and Metabolic Diseases, Chungnam National University School of Medicine, Daejeon, South Korea
| | - Ji Sun Moon
- Laboratory of Endocrinology and Immune System, Chungnam National University School of Medicine, Daejeon, South Korea.,Department of Medical Science, Chungnam National University School of Medicine, Daejeon, South Korea.,Research Center for Endocrine and Metabolic Diseases, Chungnam National University School of Medicine, Daejeon, South Korea
| | - Jingwen Tian
- Laboratory of Endocrinology and Immune System, Chungnam National University School of Medicine, Daejeon, South Korea.,Department of Medical Science, Chungnam National University School of Medicine, Daejeon, South Korea.,Research Center for Endocrine and Metabolic Diseases, Chungnam National University School of Medicine, Daejeon, South Korea
| | - Ho Yeop Lee
- Laboratory of Endocrinology and Immune System, Chungnam National University School of Medicine, Daejeon, South Korea.,Department of Medical Science, Chungnam National University School of Medicine, Daejeon, South Korea.,Research Center for Endocrine and Metabolic Diseases, Chungnam National University School of Medicine, Daejeon, South Korea
| | - Seok-Hwan Kim
- Department of Surgery, Chungnam National University School of Medicine, Daejeon, South Korea
| | - Young-Sun Lee
- Department of Internal Medicine, Korea University College of Medicine, Seoul, South Korea
| | - Jae-Han Jeon
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Hyon-Seung Yi
- Laboratory of Endocrinology and Immune System, Chungnam National University School of Medicine, Daejeon, South Korea.,Department of Medical Science, Chungnam National University School of Medicine, Daejeon, South Korea.,Research Center for Endocrine and Metabolic Diseases, Chungnam National University School of Medicine, Daejeon, South Korea
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15
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De Munck TJI, Boesch M, Verhaegh P, Masclee AAM, Jonkers D, van Pelt JF, du Plessis J, Korf H, Nevens F, Koek GH, Van der Merwe S, Verbeek J. Is there a role for neuregulin 4 in human nonalcoholic fatty liver disease? PLoS One 2021; 16:e0251822. [PMID: 33989346 PMCID: PMC8121306 DOI: 10.1371/journal.pone.0251822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 05/03/2021] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Neuregulin 4 (Nrg4), a novel adipokine enriched in brown adipose tissue has been observed to negatively regulate de novo hepatic lipogenesis and limit nonalcoholic fatty liver disease (NAFLD) progression to nonalcoholic steatohepatitis (NASH) in rodents. However, the role of Nrg4 in human NAFLD remains unclear to date. We analysed Nrg4 plasma levels and its association with liver disease severity together with the transcriptional profile of the Nrg4 pathway in liver and visceral adipose tissue (VAT) of NAFLD patients. METHODS Plasma Nrg4 levels were measured in 65 NAFLD patients and 43 healthy controls (HC). Hepatic steatosis and fibrosis were diagnosed and quantified with chemical shift MRI and transient elastography respectively. Furthermore, blood lipid levels, HOMA-IR and systemic pro-inflammatory cytokines (TNF-α, IL-6 and IFN-γ) were analysed. Microarray analyses to assess differences in the Nrg4 and its receptor family ErbB pathway in liver and VAT from an independent patient group with biopsy proven NAFL (simple steatosis) (n = 4), NASH (n = 5) and normal liver (n = 6) were performed. RESULTS Plasma Nrg4 levels were not significantly different between NAFLD patients and HC (p = 0.622). Furthermore, plasma Nrg4 levels did not correlate with the hepatic fat fraction (r = -0.028, p = 0.829) and were not significantly different between NAFLD patients with or without hepatic fibrosis (p = 0.087). Finally, the expression profile of 82 genes related to the Nrg4-ErbB pathway in liver and VAT was not significantly different between NAFL, NASH or obese controls. CONCLUSION Our study does not support a role for Nrg4 in the pathophysiology of human NAFLD.
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Affiliation(s)
- Toon J. I. De Munck
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
- School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Markus Boesch
- Laboratory of Hepatology, Department Chronic Diseases, Metabolism & Ageing (CHROMETA), KU Leuven, Leuven, Belgium
| | - Pauline Verhaegh
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
- School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Ad A. M. Masclee
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
- School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Daisy Jonkers
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
- School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Jos F. van Pelt
- Laboratory of Clinical Digestive Oncology, Department of Oncology, KU Leuven & University Hospitals Leuven and Leuven Cancer Institute (LKI), Leuven, Belgium
| | - Johannie du Plessis
- Laboratory of Hepatology, Department Chronic Diseases, Metabolism & Ageing (CHROMETA), KU Leuven, Leuven, Belgium
| | - Hannelie Korf
- Laboratory of Hepatology, Department Chronic Diseases, Metabolism & Ageing (CHROMETA), KU Leuven, Leuven, Belgium
| | - Frederik Nevens
- Laboratory of Hepatology, Department Chronic Diseases, Metabolism & Ageing (CHROMETA), KU Leuven, Leuven, Belgium
- Department of Gastroenterology and Hepatology, University Hospitals Leuven, Leuven, Belgium
| | - Ger H. Koek
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
- School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Schalk Van der Merwe
- Laboratory of Hepatology, Department Chronic Diseases, Metabolism & Ageing (CHROMETA), KU Leuven, Leuven, Belgium
- Department of Gastroenterology and Hepatology, University Hospitals Leuven, Leuven, Belgium
| | - Jef Verbeek
- Laboratory of Hepatology, Department Chronic Diseases, Metabolism & Ageing (CHROMETA), KU Leuven, Leuven, Belgium
- Department of Gastroenterology and Hepatology, University Hospitals Leuven, Leuven, Belgium
- * E-mail:
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16
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Altajar S, Baffy G. Skeletal Muscle Dysfunction in the Development and Progression of Nonalcoholic Fatty Liver Disease. J Clin Transl Hepatol 2020; 8:414-423. [PMID: 33447525 PMCID: PMC7782111 DOI: 10.14218/jcth.2020.00065] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/08/2020] [Accepted: 09/21/2020] [Indexed: 02/07/2023] Open
Abstract
The association between the pathogenesis and natural course of nonalcoholic fatty liver disease (NAFLD) and skeletal muscle dysfunction is increasingly recognized. These obesity-associated disorders originate primarily from sustained caloric excess, gradually disrupting cellular and molecular mechanisms of the adipose-muscle-liver axis resulting in end-stage tissue injury exemplified by cirrhosis and sarcopenia. These major clinical phenotypes develop through complex organ-tissue interactions from the earliest stages of NAFLD. While the role of adipose tissue expansion and remodeling is well established in the development of NAFLD, less is known about the specific interplay between skeletal muscle and the liver in this process. Here, the relationship between skeletal muscle and liver in various stages of NAFLD progression is reviewed. Current knowledge of the pathophysiology is summarized with the goal of better understanding the natural history, risk stratification, and management of NAFLD.
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Affiliation(s)
- Sarah Altajar
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Gyorgy Baffy
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
- Department of Medicine, VA Boston Healthcare System, Boston, Massachusetts, USA
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
- *Correspondence to: Gyorgy Baffy, Section of Gastroenterology, VA Boston Healthcare System, 150 South Huntington Avenue, Room A6-46, Boston, MA 12130, USA. Tel/Fax: +1-857-364-4327, E-mail:
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17
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De Munck TJI, Xu P, Vanderfeesten BLJ, Elizalde M, Masclee AAM, Nevens F, Cassiman D, Schaap FG, Jonkers DMAE, Verbeek J. The Role of Brown Adipose Tissue in the Development and Treatment of Nonalcoholic Steatohepatitis: An Exploratory Gene Expression Study in Mice. Horm Metab Res 2020; 52:869-876. [PMID: 33260239 DOI: 10.1055/a-1301-2378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Brown adipose tissue (BAT) might be a beneficial mediator in the development and treatment of nonalcoholic steatohepatitis (NASH). We aim to evaluate the gene expression of BAT activity-related genes during the development and the dietary and surgical treatment of NASH. BAT was collected from male C57BL/6J mice that received a high fat-high sucrose diet (HF-HSD) or a normal chow diet (NCD) for 4 and 20 weeks (n=8-9 per dietary group and timepoint) and from mice that underwent dietary intervention (return to NCD) (n=8), roux-en-y gastric bypass (RYGB) (n=6), or sham procedure (n=6) after 12 weeks HF-HSD. Expression of BAT genes involved in lipid metabolism (Cd36 and Cpt1b; p<0.05) and energy expenditure (Ucp1 and Ucp3; p<0.05) were significantly increased after 4 weeks HF-HSD compared with NCD, whereas in the occurrence of NASH after 20 weeks HF-HSD no difference was observed. We observed no differences in gene expression regarding lipid metabolism or energy expenditure at 8 weeks after dietary intervention (no NASH) compared with HF-HSD mice (NASH), nor in mice that underwent RYGB compared with SHAM. However, dietary intervention and RYGB both decreased the BAT gene expression of inflammatory cytokines (Il1b, Tnf-α and MCP-1; p<0.05). Gene expression of the batokine neuregulin 4 was significantly decreased after 20 weeks HF-HSD (p<0.05) compared with NCD, but was restored by dietary intervention and RYGB (p<0.05). In conclusion, BAT is hallmarked by dynamic alterations in the gene expression profile during the development of NASH and can be modulated by dietary intervention and bariatric surgery.
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Affiliation(s)
- Toon J I De Munck
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
- School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Pan Xu
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
- School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Brechtje L J Vanderfeesten
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Montserrat Elizalde
- School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Ad A M Masclee
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
- School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Frederik Nevens
- Department of Gastroenterology and Hepatology, University Hospitals KU Leuven, Leuven, Belgium
| | - David Cassiman
- Department of Gastroenterology and Hepatology, University Hospitals KU Leuven, Leuven, Belgium
| | - Frank G Schaap
- School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
- Department of Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands
- Department of General, Visceral and Transplantation Surgery, RWTH University Hospital Aachen, Aachen, Germany
| | - Daisy M A E Jonkers
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
- School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Jef Verbeek
- Department of Gastroenterology and Hepatology, University Hospitals KU Leuven, Leuven, Belgium
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Yau WW, Yen PM. Thermogenesis in Adipose Tissue Activated by Thyroid Hormone. Int J Mol Sci 2020; 21:ijms21083020. [PMID: 32344721 PMCID: PMC7215895 DOI: 10.3390/ijms21083020] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/19/2020] [Accepted: 04/22/2020] [Indexed: 02/07/2023] Open
Abstract
Thermogenesis is the production of heat that occurs in all warm-blooded animals. During cold exposure, there is obligatory thermogenesis derived from body metabolism as well as adaptive thermogenesis through shivering and non-shivering mechanisms. The latter mainly occurs in brown adipose tissue (BAT) and muscle; however, white adipose tissue (WAT) also can undergo browning via adrenergic stimulation to acquire thermogenic potential. Thyroid hormone (TH) also exerts profound effects on thermoregulation, as decreased body temperature and increased body temperature occur during hypothyroidism and hyperthyroidism, respectively. We have termed the TH-mediated thermogenesis under thermoneutral conditions “activated” thermogenesis. TH acts on the brown and/or white adipose tissues to induce uncoupled respiration through the induction of the uncoupling protein (Ucp1) to generate heat. TH acts centrally to activate the BAT and browning through the sympathetic nervous system. However, recent studies also show that TH acts peripherally on the BAT to directly stimulate Ucp1 expression and thermogenesis through an autophagy-dependent mechanism. Additionally, THs can exert Ucp1-independent effects on thermogenesis, most likely through activation of exothermic metabolic pathways. This review summarizes thermogenic effects of THs on adipose tissues.
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Affiliation(s)
- Winifred W Yau
- Laboratory of Hormonal Regulation, Cardiovascular and Metabolic Disorders Program, Duke NUS Medical School, Singapore 169857, Singapore
| | - Paul M Yen
- Laboratory of Hormonal Regulation, Cardiovascular and Metabolic Disorders Program, Duke NUS Medical School, Singapore 169857, Singapore
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27708, USA
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19
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Xia Y, Zhang S, Zhang Q, Liu L, Meng G, Wu H, Bao X, Gu Y, Sun S, Wang X, Zhou M, Jia Q, Song K, Wu Q, Niu K, Zhao Y. Insoluble dietary fibre intake is associated with lower prevalence of newly-diagnosed non-alcoholic fatty liver disease in Chinese men: a large population-based cross-sectional study. Nutr Metab (Lond) 2020; 17:4. [PMID: 31956330 PMCID: PMC6958720 DOI: 10.1186/s12986-019-0420-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 12/20/2019] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND The health benefits of dietary fibre (DF) intake on non-alcoholic fatty liver disease (NAFLD) are controversial. Thus, this large cross-sectional study aimed to determine the associations between DF intake and the prevalence of newly-diagnosed NAFLD in a large general population. METHODS A total of 23,529 participants were enrolled in the analyses. Newly-diagnosed NAFLD was diagnosed according to liver ultrasonography and history of alcohol intake. DF intake was assessed using a validated self-administered food frequency questionnaire. Logistic regression analysis was applied to estimate the associations between DF intake and NAFLD. RESULTS In total, 18.81% (n = 4426) of the participants were newly diagnosed with NAFLD. Compared with the participants in the lowest quartile of DF intake, the ORs (95% CI) for the participants in the highest quartile were 0.81 (0.67, 0.97), 0.78 (0.62, 0.99), and 0.85 (0.62, 1.17) for all participants, men, and women, respectively. Compared with the participants in the lowest quartile of insoluble DF intake, the ORs (95% CI) for the participants in the highest quartile were 0.70 (0.58, 0.85), 0.60 (0.47, 0.76), and 0.95 (0.68, 1.32) in all participants, men, and women, respectively. No association was observed between soluble DF intake and NAFLD. DF from whole grain, soy foods, vegetables, and nuts but not fruits were negatively associated with NAFLD. CONCLUSIONS A higher intake of insoluble DF is associated with lower prevalence of newly-diagnosed NAFLD in men. Moreover, intake DF from whole grain, soy foods, vegetables, and nuts, but not fruits have favorable effect on the prevalence of newly diagnosed NAFLD. Further cohort studies and randomized controlled trials are needed to validate this finding.
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Affiliation(s)
- Yang Xia
- Department of Clinical Epidemiology, Shengjing Hospital of China Medical University, No. 36, San Hao Street, Shenyang, 110004 Liaoning China
| | - Shunming Zhang
- Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, 300070 China
| | - Qing Zhang
- Health Management Centre, Tianjin Medical University General Hospital, Tianjin, China
| | - Li Liu
- Health Management Centre, Tianjin Medical University General Hospital, Tianjin, China
| | - Ge Meng
- Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, 300070 China
| | - Hongmei Wu
- Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, 300070 China
| | - Xue Bao
- Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, 300070 China
| | - Yeqing Gu
- Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, 300070 China
| | - Shaomei Sun
- Health Management Centre, Tianjin Medical University General Hospital, Tianjin, China
| | - Xing Wang
- Health Management Centre, Tianjin Medical University General Hospital, Tianjin, China
| | - Ming Zhou
- Health Management Centre, Tianjin Medical University General Hospital, Tianjin, China
| | - Qiyu Jia
- Health Management Centre, Tianjin Medical University General Hospital, Tianjin, China
| | - Kun Song
- Health Management Centre, Tianjin Medical University General Hospital, Tianjin, China
| | - Qijun Wu
- Department of Clinical Epidemiology, Shengjing Hospital of China Medical University, No. 36, San Hao Street, Shenyang, 110004 Liaoning China
| | - Kaijun Niu
- Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, 300070 China
- Health Management Centre, Tianjin Medical University General Hospital, Tianjin, China
| | - Yuhong Zhao
- Department of Clinical Epidemiology, Shengjing Hospital of China Medical University, No. 36, San Hao Street, Shenyang, 110004 Liaoning China
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Abstract
White adipose tissue (WAT) dysfunction is generally thought to promote the development of alcoholic liver disease (ALD) in alcoholics by releasing free fatty acids and inflammatory mediators. This explains, at least in part, the synergistic or additive effects of alcohol and obesity on liver disease progression. In this issue of the JCI, Shen et al. establish a previously unrecognized concept that brain alcohol sensing enhances thermogenesis of brown adipose tissue (BAT) through sympathetic nerve activation. BAT functions as hepatoprotective machinery to counteract the development of ALD, implying a therapeutic potential of BAT activity modulation for the treatment of ALD.
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21
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Shen H, Jiang L, Lin JD, Omary MB, Rui L. Brown fat activation mitigates alcohol-induced liver steatosis and injury in mice. J Clin Invest 2019; 129:2305-2317. [PMID: 30888335 PMCID: PMC6546460 DOI: 10.1172/jci124376] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 03/14/2019] [Indexed: 02/06/2023] Open
Abstract
Chronic alcohol consumption causes liver injury, inflammation and fibrosis, thereby increasing morbidity and mortality. Paradoxically, modest drinking is believed to confer metabolic improvement, but the underlying mechanism remains elusive. Here, we have identified a novel hepatoprotective brain/brown adipose tissue (BAT)/liver axis. Alcohol consumption or direct alcohol administration into the brain stimulated hypothalamic neural circuits and sympathetic nerves innervating BAT, and dramatically increased BAT uncoupling protein 1 (Ucp1) expression and activity in a BAT sympathetic nerve-dependent manner. BAT and beige fat oxidized fatty acids to fuel Ucp1-mediated thermogenesis, thereby inhibiting lipid trafficking into the liver. BAT also secreted several adipokines, including adiponectin that suppressed hepatocyte injury and death. Genetic deletion of Ucp1 profoundly augmented alcohol-induced liver steatosis, injury, inflammation and fibrosis in male and female mice. Conversely, activation of BAT and beige fat through cold exposure suppressed alcoholic liver disease development. Our results unravel an unrecognized brain alcohol-sensing/sympathetic nerve/BAT/liver axis that counteracts liver steatosis and injury.
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Affiliation(s)
- Hong Shen
- Department of Molecular & Integrative Physiology
| | - Lin Jiang
- Department of Molecular & Integrative Physiology
| | - Jiandie D. Lin
- Life Sciences Institute and Department of Cell & Developmental Biology, and
| | - M. Bishr Omary
- Department of Molecular & Integrative Physiology
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Liangyou Rui
- Department of Molecular & Integrative Physiology
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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22
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Emerging awareness on the importance of skeletal muscle in liver diseases: time to dig deeper into mechanisms! Clin Sci (Lond) 2019; 133:465-481. [DOI: 10.1042/cs20180421] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/09/2019] [Accepted: 01/23/2019] [Indexed: 02/07/2023]
Abstract
Abstract
Skeletal muscle is a tissue that represents 30–40% of total body mass in healthy humans and contains up to 75% of total body proteins. It is thus the largest organ in non-obese subjects. The past few years have seen increasing awareness of the prognostic value of appreciating changes in skeletal muscle compartment in various chronic diseases. Hence, a low muscle mass, a low muscle function and muscle fatty infiltration are linked with poor outcomes in many pathological conditions. In particular, an affluent body of evidence links the severity, the complications and mortality of chronic liver disease (CLD) with skeletal muscle depletion. Yet it is still not clear whether low muscle mass is a cause, an aggravating factor, a consequence of the ongoing disease, or an epiphenomenon reflecting general alteration in the critically ill patient. The mechanisms by which the muscle compartment influences disease prognosis are still largely unknown. In addition, whether muscle alterations contribute to liver disease progression is an unanswered question. Here, we first review basic knowledge about muscle compartment to draw a conceptual framework for interpreting skeletal muscle alteration in CLD. We next describe recent literature on muscle wasting in cirrhosis and liver transplantation. We then discuss the implication of skeletal muscle compartment in non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH), focusing on plausible metabolic disruption in muscle compartment that might participate in NAFLD progression. Finally, we discuss shortcomings and challenges we need to address in the near future prior to designate the muscle compartment as a therapeutic target in CLD.
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Activation of brown adipose tissue enhances the efficacy of caloric restriction for treatment of nonalcoholic steatohepatitis. J Transl Med 2019; 99:4-16. [PMID: 30258096 DOI: 10.1038/s41374-018-0120-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 07/27/2018] [Accepted: 08/02/2018] [Indexed: 12/11/2022] Open
Abstract
Nonalcoholic steatohepatitis (NASH) is the form of nonalcoholic fatty liver disease that can evolve into cirrhosis. Lifestyle modifications achieving 10% weight loss reverse NASH, but there are no effective approved drug treatments. We previously identified defective adaptive thermogenesis as a factor contributing to metabolic syndrome and hepatic steatosis. We have now tested whether increasing nonshivering thermogenesis can improve preexisting NASH in mice. In high-fat diet-fed foz/foz mice with established NASH, treatment with β3AR agonist restored brown adipose tissue (BAT) function, decreased body weight, improved glucose tolerance, and reduced hepatic lipid content compared to untreated counterparts, but had no impact on liver inflammation or on nonalcoholic fatty liver disease activity score (NAS). Similarly, β3AR agonist did not alter liver pathology in other steatohepatitis models, including MCD diet-fed diabetic obese db/db mice. Caloric restriction alone alleviated the hepatic inflammatory signature in foz/foz mice. Addition of a β3AR agonist to mice subjected to caloric restriction enhanced weight loss and glucose tolerance, and improved liver steatosis, hepatocellular injury, and further reduced liver inflammation. These changes contributed to a significantly lower NAS score such as no (0/9) animals in this group fulfilled the criteria for NASH pathology compared to eight out of ten mice under caloric restriction alone. In conclusion, β3AR agonist counteracts features of the metabolic syndrome and alleviates steatosis, but does not reverse NASH. However, when coupled with weight loss therapy, BAT stimulation provides additional therapeutic advantages and reverses NASH.
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Carpentier AC, Blondin DP, Virtanen KA, Richard D, Haman F, Turcotte ÉE. Brown Adipose Tissue Energy Metabolism in Humans. Front Endocrinol (Lausanne) 2018; 9:447. [PMID: 30131768 PMCID: PMC6090055 DOI: 10.3389/fendo.2018.00447] [Citation(s) in RCA: 197] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 07/20/2018] [Indexed: 12/16/2022] Open
Abstract
The demonstration of metabolically active brown adipose tissue (BAT) in humans primarily using positron emission tomography coupled to computed tomography (PET/CT) with the glucose tracer 18-fluorodeoxyglucose (18FDG) has renewed the interest of the scientific and medical community in the possible role of BAT as a target for the prevention and treatment of obesity and type 2 diabetes (T2D). Here, we offer a comprehensive review of BAT energy metabolism in humans. Considerable advances in methods to measure BAT energy metabolism, including nonesterified fatty acids (NEFA), chylomicron-triglycerides (TG), oxygen, Krebs cycle rate, and intracellular TG have led to very good quantification of energy substrate metabolism per volume of active BAT in vivo. These studies have also shown that intracellular TG are likely the primary energy source of BAT upon activation by cold. Current estimates of BAT's contribution to energy expenditure range at the lower end of what would be potentially clinically relevant if chronically sustained. Yet, 18FDG PET/CT remains the gold-standard defining method to quantify total BAT volume of activity, used to calculate BAT's total energy expenditure. Unfortunately, BAT glucose metabolism better reflects BAT's insulin sensitivity and blood flow. It is now clear that most glucose taken up by BAT does not fuel mitochondrial oxidative metabolism and that BAT glucose uptake can therefore be disconnected from thermogenesis. Furthermore, BAT thermogenesis is efficiently recruited upon repeated cold exposure, doubling to tripling its total oxidative capacity, with reciprocal reduction of muscle thermogenesis. Recent data suggest that total BAT volume may be much larger than the typically observed 50-150 ml with 18FDG PET/CT. Therefore, the current estimates of total BAT thermogenesis, largely relying on total BAT volume using 18FDG PET/CT, may underestimate the true contribution of BAT to total energy expenditure. Quantification of the contribution of BAT to energy expenditure begs for the development of more integrated whole body in vivo methods.
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Affiliation(s)
- André C. Carpentier
- Division of Endocrinology, Department of Medicine, Centre de Recherche du CHUS, Université de Sherbrooke, Sherbrooke, QC, Canada
| | | | - Kirsi A. Virtanen
- Turku PET Centre, Turku University Hospital, Turku, Finland
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland (UEF), Kuopio, Finland
| | - Denis Richard
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec City, QC, Canada
| | - François Haman
- Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Éric E. Turcotte
- Department of Nuclear Medicine and Radiobiology, Centre de Recherche du CHUS, Université de Sherbrooke, Sherbrooke, QC, Canada
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25
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Nam HY, Jun S. Association between active brown adipose tissue and coronary artery calcification in healthy men. Nuklearmedizin 2018; 56:184-190. [DOI: 10.3413/nukmed-0887-17-03] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 07/31/2017] [Indexed: 12/30/2022]
Abstract
Summary
Aim: We compared various clinical factors between persons with active brown adipose tissue (ABAT) and matched controls, and investigated the relationship between the presence of ABAT and coronary artery calcification (CAC) with respect to arterial inflammation.Methods: We retrospectively reviewed fluorine-18-labeled fluoro- 2-deoxy-D-glucose (F-18 FDG) positron emission tomography/computed tomography (PET/CT) data from men who underwent general health check-ups. Sixty-seven men with ABAT were identified and were matched with controls at a 1:1 ratio. Peripheral blood samples were obtained and the levels of various laboratory parameters were measured just before FDG PET/CT studies. Arterial inflammation was measured in the ascending aorta, venous mean standardized uptake value (SUV) was collected from the superior vena cava as FDG uptake on PET, and background-corrected SUV was calculated as the target-to-background ratio (TBR) and blood- subtracted SUVmax (bsSUVmax). CAC was as-sessed using CT images acquired from a PET/ CT scanner.Results: The prevalence of fatty liver (p = 0.048) and CAC (p = 0.026) was lower in men with ABAT compared to matched controls. Arterial SUVmax (1.72 ± 0.23 vs. 1.88 ± 0.23, p < 0.001), TBR (1.18 ± 0.14 vs. 1.29 ± 0.13, p < 0.001), and bsSUVmax (0.25 ± 0.18 vs. 0.41 ± 0.16, p < 0.001) were significantly lower in men with ABAT. ABAT (odds ratio [OR] = 0.19, p=0.024) and high- density lipoprotein cholesterol (OR = 0.95, p = 0.037) were independent factors associated with CAC according to multiple logistic regression analysis.Conclusion: ABAT is associated with down-regulated arterial inflammation and may exert a protective effect against the development of atherosclerosis.
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Correlation of Brown Adipose Tissue with Other Body Fat Compartments and Patient Characteristics: A Retrospective Analysis in a Large Patient Cohort Using PET/CT. Acad Radiol 2018; 25:102-110. [PMID: 29108812 DOI: 10.1016/j.acra.2017.09.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 09/06/2017] [Accepted: 09/06/2017] [Indexed: 12/11/2022]
Abstract
RATIONALE AND OBJECTIVES The objective of this study was to assess the relationship of brown adipose tissue (BAT) activity with different fat compartments of the body, body mass index (BMI), outdoor temperature, thyroid-stimulating hormone (TSH) levels, blood glucose, age, and sex in a large patient population using F-18-fluordesoxyglucose positron emission tomography-computer tomography (FDG-PET/CT) scans obtained under thermoneutral conditions. MATERIALS AND METHODS FDG-PET/CT scans of 4852 patients were retrospectively analyzed for BAT activity. The volumes of the different fat compartments visceral adipose tissue (VAT), subcutaneous adipose tissue (SCAT), and liver fat, were assessed by computed tomography. Age, sex, TSH levels, blood glucose levels, BMI, primary disease, and the outdoor temperature were determined. Multiple linear regression analyses were performed to identify independent relationships between the parameters. RESULTS The VAT, SCAT, and liver fat content were lower in BAT-positive patients than in BAT-negative patients (each P < 0.0001). BAT-positive patients had a lower BMI (P < 0.0001) and were more often female (P < 0.0001), younger (P < 0.0001), and had higher TSH levels (P = 0.0002), whereas the outdoor temperature and the blood glucose level were not different compared to BAT-negative patients. Age, sex, VAT, and SCAT were independent factors related to BAT. CONCLUSIONS Age, sex, and VAT are the most important determinants of BAT activity under thermoneutral conditions. VAT reflects the association between BAT activity and body fat mass more clearly than BMI. The strength of the association between VAT and BAT decreases during aging in men, but increases in women. This may indicate a different importance of BAT activity for obesity in men and in women.
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27
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Abstract
Brown and beige adipocytes arise from distinct developmental origins. Brown adipose tissue (BAT) develops embryonically from precursors that also give to skeletal muscle. Beige fat develops postnatally and is highly inducible. Beige fat recruitment is mediated by multiple mechanisms, including de novo beige adipogenesis and white-to-brown adipocyte transdifferentiaiton. Beige precursors reside around vasculatures, and proliferate and differentiate into beige adipocytes. PDGFRα+Ebf2+ precursors are restricted to beige lineage cells, while another PDGFRα+ subset gives rise to beige adipocytes, white adipocytes, or fibrogenic cells. White adipocytes can be reprogramed and transdifferentiated into beige adipocytes. Brown and beige adipocytes display many similar properties, including multilocular lipid droplets, dense mitochondria, and expression of UCP1. UCP1-mediated thermogenesis is a hallmark of brown/beige adipocytes, albeit UCP1-independent thermogenesis also occurs. Development, maintenance, and activation of BAT/beige fat are guided by genetic and epigenetic programs. Numerous transcriptional factors and coactivators act coordinately to promote BAT/beige fat thermogenesis. Epigenetic reprograming influences expression of brown/beige adipocyte-selective genes. BAT/beige fat is regulated by neuronal, hormonal, and immune mechanisms. Hypothalamic thermal circuits define the temperature setpoint that guides BAT/beige fat activity. Metabolic hormones, paracrine/autocrine factors, and various immune cells also play a critical role in regulating BAT/beige fat functions. BAT and beige fat defend temperature homeostasis, and regulate body weight and glucose and lipid metabolism. Obesity is associated with brown/beige fat deficiency, and reactivation of brown/beige fat provides metabolic health benefits in some patients. Pharmacological activation of BAT/beige fat may hold promise for combating metabolic diseases. © 2017 American Physiological Society. Compr Physiol 7:1281-1306, 2017.
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Affiliation(s)
- Liangyou Rui
- Department of Molecular and Integrative Physiology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
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28
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Pervin S, Singh V, Tucker A, Collazo J, Singh R. Modulation of transforming growth factor-β/follistatin signaling and white adipose browning: therapeutic implications for obesity related disorders. Horm Mol Biol Clin Investig 2017; 31:/j/hmbci.ahead-of-print/hmbci-2017-0036/hmbci-2017-0036.xml. [PMID: 28888087 DOI: 10.1515/hmbci-2017-0036] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 07/17/2017] [Indexed: 12/15/2022]
Abstract
Obesity is a major risk factor for the development of diabetes, insulin resistance, dyslipidemia, cardiovascular disease and other related metabolic conditions. Obesity develops from perturbations in overall cellular bioenergetics when energy intake chronically exceeds total energy expenditure. Lifestyle interventions based on reducing total energy uptake and increasing activities including exercise have proved ineffective in the prevention and treatment of obesity because of poor adherence to such interventions for an extended period of time. Brown adipose tissue (BAT) has an extraordinary metabolic capacity to burn excess stored energy and holds great promise in combating obesity and related diseases. This unique ability to nullify the effects of extra energy intake of these specialized tissues has provided attractive perspectives for the therapeutic potential of BAT in humans. Browning of white adipose tissue by promoting the expression and activity of key mitochondrial uncoupling protein 1 (UCP1) represents an exciting new strategy to combat obesity via enhanced energy dissipation. Members of the transforming growth factor-beta (TGF-β) superfamily including myostatin and follistatin have recently been demonstrated to play a key role in regulating white adipose browning both in in-vitro and in-vivo animal models and thereby present attractive avenues for exploring the therapeutic potential for the treatment of obesity and related metabolic diseases.
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29
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Mulya A, Kirwan JP. Brown and Beige Adipose Tissue: Therapy for Obesity and Its Comorbidities? Endocrinol Metab Clin North Am 2016; 45:605-21. [PMID: 27519133 PMCID: PMC5206678 DOI: 10.1016/j.ecl.2016.04.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Overweight and obesity are global health problems placing an ever-increasing demand on health care systems. Brown adipose tissue (BAT) is present in significant amounts in adults. BAT has potential as a fuel for oxidation and dissipation as heat production, which makes it an attractive target for obesity therapy. BAT activation results in increased energy expenditure via thermogenesis. The role of BAT/beige adipocyte activation on whole body energy homeostasis, body weight management/regulation, and whole body glucose and lipid homeostasis remains unproven. This paper reviews knowledge on brown/beige adipocytes in energy expenditure and how it may impact obesity therapy and its comorbidities.
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Affiliation(s)
- Anny Mulya
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, NE40, Cleveland, OH 44195, USA
| | - John P Kirwan
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, NE40, Cleveland, OH 44195, USA; Department of Nutrition, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Metabolic Translational Research Center, Endocrine and Metabolism Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
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30
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Scheja L, Heeren J. Metabolic interplay between white, beige, brown adipocytes and the liver. J Hepatol 2016; 64:1176-1186. [PMID: 26829204 DOI: 10.1016/j.jhep.2016.01.025] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 01/11/2016] [Accepted: 01/25/2016] [Indexed: 02/07/2023]
Abstract
In mammalian evolution, three types of adipocytes have developed, white, brown and beige adipocytes. White adipocytes are the major constituents of white adipose tissue (WAT), the predominant store for energy-dense triglycerides in the body that are released as fatty acids during catabolic conditions. The less abundant brown adipocytes, the defining parenchymal cells of brown adipose tissue (BAT), internalize triglycerides that are stored intracellularly in multilocular lipid droplets. Beige adipocytes (also known as brite or inducible brown adipocytes) are functionally very similar to brown adipocytes and emerge in specific WAT depots in response to various stimuli including sustained cold exposure. The activation of brown and beige adipocytes (together referred to as thermogenic adipocytes) causes both the hydrolysis of stored triglycerides as well as the uptake of lipids and glucose from the circulation. Together, these fuels are combusted for heat production to maintain body temperature in mammals including adult humans. Given that heating by brown and beige adipocytes is a very-well controlled and energy-demanding process which entails pronounced shifts in energy fluxes, it is not surprising that an intensive interplay exists between the various adipocyte types and parenchymal liver cells, and that this influences systemic metabolic fluxes and endocrine networks. In this review we will emphasize the role of hepatic factors that regulate the metabolic activity of white and thermogenic adipocytes. In addition, we will discuss the relevance of lipids and hormones that are secreted by white, brown and beige adipocytes regulating liver metabolism in order to maintain systemic energy metabolism in health and disease.
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Affiliation(s)
- Ludger Scheja
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.
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Brown adipose tissue: a potential target in the fight against obesity and the metabolic syndrome. Clin Sci (Lond) 2015; 129:933-49. [DOI: 10.1042/cs20150339] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BAT (brown adipose tissue) is the main site of thermogenesis in mammals. It is essential to ensure thermoregulation in newborns. It is also found in (some) adult humans. Its capacity to oxidize fatty acids and glucose without ATP production contributes to energy expenditure and glucose homoeostasis. Brown fat activation has thus emerged as an attractive therapeutic target for the treatment of obesity and the metabolic syndrome. In the present review, we integrate the recent advances on the metabolic role of BAT and its relation with other tissues as well as its potential contribution to fighting obesity and the metabolic syndrome.
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The role of active brown adipose tissue in human metabolism. Eur J Nucl Med Mol Imaging 2015; 43:355-361. [DOI: 10.1007/s00259-015-3166-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 08/05/2015] [Indexed: 12/19/2022]
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Lonardo A, Ballestri S, Marchesini G, Angulo P, Loria P. Nonalcoholic fatty liver disease: a precursor of the metabolic syndrome. Dig Liver Dis 2015; 47:181-90. [PMID: 25739820 DOI: 10.1016/j.dld.2014.09.020] [Citation(s) in RCA: 481] [Impact Index Per Article: 53.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 09/19/2014] [Accepted: 09/21/2014] [Indexed: 02/07/2023]
Abstract
The conventional paradigm of nonalcoholic fatty liver disease representing the "hepatic manifestation of the metabolic syndrome" is outdated. We identified and summarized longitudinal studies that, supporting the association of nonalcoholic fatty liver disease with either type 2 diabetes mellitus or metabolic syndrome, suggest that nonalcoholic fatty liver disease precedes the development of both conditions. Online Medical databases were searched, relevant articles were identified, their references were further assessed and tabulated data were checked. Although several cross-sectional studies linked nonalcoholic fatty liver disease to either diabetes and other components of the metabolic syndrome, we focused on 28 longitudinal studies which provided evidence for nonalcoholic fatty liver disease as a risk factor for the future development of diabetes. Moreover, additional 19 longitudinal reported that nonalcoholic fatty liver disease precedes and is a risk factor for the future development of the metabolic syndrome. Finally, molecular and genetic studies are discussed supporting the view that aetiology of steatosis and lipid intra-hepatocytic compartmentation are a major determinant of whether fatty liver is/is not associated with insulin resistance and metabolic syndrome. Data support the novel paradigm of nonalcoholic fatty liver disease as a strong determinant for the development of the metabolic syndrome, which has potentially relevant clinical implications for diagnosing, preventing and treating metabolic syndrome.
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Affiliation(s)
- Amedeo Lonardo
- AUSL Modena and University of Modena and Reggio Emilia, Department of Biomedical, Metabolic and Neural Sciences, Division of Internal Medicine, NOCSAE - Baggiovara, Modena, Italy.
| | - Stefano Ballestri
- AUSL Modena, Department of Internal Medicine, Division of Internal Medicine, Hospital of Pavullo, Pavullo nel Frignano, Italy
| | - Giulio Marchesini
- "Alma Mater Studiorum" University, Unit of Metabolic Diseases and Clinical Dietetics, Bologna, Italy
| | - Paul Angulo
- University of Kentucky, Division of Digestive Diseases & Nutrition, Section of Hepatology, Medical Center, Lexington, KY, USA
| | - Paola Loria
- AUSL Modena and University of Modena and Reggio Emilia, Department of Biomedical, Metabolic and Neural Sciences, Division of Internal Medicine, NOCSAE - Baggiovara, Modena, Italy
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Porter C, Chondronikola M, Sidossis LS. The Therapeutic Potential of Brown Adipocytes in Humans. Front Endocrinol (Lausanne) 2015; 6:156. [PMID: 26528238 PMCID: PMC4602197 DOI: 10.3389/fendo.2015.00156] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 09/18/2015] [Indexed: 12/20/2022] Open
Abstract
Obesity and its metabolic consequences represent a significant clinical problem. From a thermodynamic standpoint, obesity results from a discord in energy intake and expenditure. To date, lifestyle interventions based on reducing energy intake and/or increasing energy expenditure have proved ineffective in the prevention and/or treatment of obesity, owing to poor long-term adherence to such interventions. Thus, an effective strategy to prevent or correct obesity is currently lacking. As the combustion engines of our cells, mitochondria play a critical role in energy expenditure. At a whole-body level, approximately 80% of mitochondrial membrane potential generated by fuel oxidation is used to produce ATP, and the remaining 20% is lost through heat-producing uncoupling reactions. The coupling of mitochondrial respiration to ATP production represents an important component in whole-body energy expenditure. Brown adipose tissue (BAT) is densely populated with mitochondria containing the inner mitochondrial proton carrier uncoupling protein 1 (UCP1). UCP1 uncouples oxidative phosphorylation, meaning that mitochondrial membrane potential is dissipated as heat. The recent rediscovery of BAT depots in adult humans has rekindled scientific interest in the manipulation of mitochondrial uncoupling reactions as a means to increase metabolic rate, thereby counteracting obesity and its associated metabolic phenotype. In this article, we discuss the evidence for the role BAT plays in metabolic rate and glucose and lipid metabolism in humans and the potential for UCP1 recruitment in the white adipose tissue of humans. While the future holds much promise for a therapeutic role of UCP1 expressing adipocytes in human energy metabolism, particularly in the context of obesity, tissue-specific strategies that activate or recruit UCP1 in human adipocytes represent an obligatory translational step for this early promise to be realized.
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Affiliation(s)
- Craig Porter
- Metabolism Unit, Shriners Hospitals for Children-Galveston, Galveston, TX, USA
- Department of Surgery, University of Texas Medical Branch, Galveston, TX, USA
- *Correspondence: Craig Porter and Labros S. Sidossis, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77550, USA, ;
| | - Maria Chondronikola
- Metabolism Unit, Shriners Hospitals for Children-Galveston, Galveston, TX, USA
- Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston, TX, USA
| | - Labros S. Sidossis
- Metabolism Unit, Shriners Hospitals for Children-Galveston, Galveston, TX, USA
- Department of Surgery, University of Texas Medical Branch, Galveston, TX, USA
- Department of Nutrition and Dietetics, Harokopio University of Athens, Athens, Greece
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA
- *Correspondence: Craig Porter and Labros S. Sidossis, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77550, USA, ;
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Jha P, Knopf A, Koefeler H, Mueller M, Lackner C, Hoefler G, Claudel T, Trauner M. Role of adipose tissue in methionine-choline-deficient model of non-alcoholic steatohepatitis (NASH). Biochim Biophys Acta Mol Basis Dis 2014; 1842:959-70. [PMID: 24594481 PMCID: PMC4034162 DOI: 10.1016/j.bbadis.2014.02.012] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Revised: 02/17/2014] [Accepted: 02/23/2014] [Indexed: 02/06/2023]
Abstract
Methionine–choline-deficient (MCD) diet is a widely used dietary model of non-alcoholic steatohepatitis (NASH) in rodents. However, the contribution of adipose tissue to MCD-induced steatosis, and inflammation as features of NASH are not fully understood. The goal of this study was to elucidate the role of adipose tissue fatty acid (FA) metabolism, adipogenesis, lipolysis, inflammation and subsequent changes in FA profiles in serum and liver in the pathogenesis of steatohepatitis. We therefore fed ob/ob mice with control or MCD diet for 5 weeks. MCD-feeding increased adipose triglyceride lipase and hormone sensitive lipase activities in all adipose depots which may be attributed to increased systemic FGF21 levels. The highest lipase enzyme activity was exhibited by visceral WAT. Non-esterified fatty acid (NEFA)-18:2n6 was the predominantly elevated FA species in serum and liver of MCD-fed ob/ob mice, while overall serum total fatty acid (TFA) composition was reduced. In contrast, an overall increase of all FA species from TFA pool was found in liver, reflecting the combined effects of increased FA flux to liver, decreased FA oxidation and decrease in lipase activity in liver. NAFLD activity score was increased in liver, while WAT showed no changes and BAT showed even reduced inflammation. Conclusion: This study demonstrates a key role for adipose tissue lipases in the pathogenesis of NASH and provides a comprehensive lipidomic profiling of NEFA and TFA homeostasis in serum and liver. Our findings provide novel mechanistic insights for the role of WAT in progression of MCD-induced liver injury. MCD model of NASH increases lipase activity in WAT as a critical determinant of hepatic FA flux and lipotoxicity. The maximal increase of ATGL and HSL activity is in visceral WAT. Increased lipase activity may be due to enhanced FGF21 signaling. NEFA-18:2n6 is preferentially increased in serum and liver due to lipolysis in WAT. MCD diet enhances the activity of BAT and diminishes its inflammatory markers.
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Affiliation(s)
- Pooja Jha
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria; Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria; Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Astrid Knopf
- Core Facility for Mass Spectrometry, Medical University of Graz, Austria
| | - Harald Koefeler
- Core Facility for Mass Spectrometry, Medical University of Graz, Austria
| | - Michaela Mueller
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria; Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Carolin Lackner
- Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Gerald Hoefler
- Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Thierry Claudel
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Michael Trauner
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria.
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Bauwens M, Wierts R, van Royen B, Bucerius J, Backes W, Mottaghy F, Brans B. Molecular imaging of brown adipose tissue in health and disease. Eur J Nucl Med Mol Imaging 2014; 41:776-91. [PMID: 24509875 DOI: 10.1007/s00259-013-2611-8] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 10/07/2013] [Indexed: 12/25/2022]
Abstract
PURPOSE Brown adipose tissue (BAT) has transformed from an interfering tissue in oncological (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) to an independent imaging research field. This review takes the perspective from the imaging methodology on which human BAT research has come to rely on heavily. METHODS This review analyses relevant PubMed-indexed publications that discuss molecular imaging methods of BAT. In addition, reported links between BAT and human diseases such as obesity are discussed, and the possibilities for imaging in these fields are highlighted. Radiopharmaceuticals aiming at several different biological mechanisms of BAT are discussed and evaluated. RESULTS Prospective, dedicated studies allow visualization of BAT function in a high percentage of human subjects. BAT dysfunction has been implicated in obesity, linked with diabetes and associated with cachexia and atherosclerosis. Presently, (18)F-FDG PET/CT is the most useful tool for evaluating therapies aiming at BAT activity. In addition to (18)F-FDG, other radiopharmaceuticals such as (99m)Tc-sestamibi, (123)I-metaiodobenzylguanidine (MIBG), (18)F-fluorodopa and (18)F-14(R,S)-[(18)F]fluoro-6-thia-heptadecanoic acid (FTHA) may have a potential for visualizing other aspects of BAT activity. MRI methods are under continuous development and provide the prospect of functional imaging without ionizing radiation. CONCLUSION Molecular imaging of BAT can be used to quantitatively assess different aspects of BAT metabolic activity.
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Affiliation(s)
- Matthias Bauwens
- Department of Medical Imaging, Division of Nuclear Medicine, MUMC, Maastricht, Netherlands
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Mirbolooki MR, Upadhyay SK, Constantinescu CC, Pan ML, Mukherjee J. Adrenergic pathway activation enhances brown adipose tissue metabolism: a [¹⁸F]FDG PET/CT study in mice. Nucl Med Biol 2013; 41:10-6. [PMID: 24090673 DOI: 10.1016/j.nucmedbio.2013.08.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Revised: 08/13/2013] [Accepted: 08/21/2013] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Pharmacologic approaches to study brown adipocyte activation in vivo with a potential of being translational to humans are desired. The aim of this study was to examine pre- and postsynaptic targeting of adrenergic system for enhancing brown adipose tissue (BAT) metabolism quantifiable by [(18)F]fluoro-2-deoxyglucose ([(18)F]FDG) positron emission tomography (PET)/computed tomography (CT) in mice. METHODS A β₃-adrenoreceptor selective agonist (CL 316243), an adenylyl cyclase enzyme activator (forskolin) and a potent blocker of presynaptic norepinephrine transporter (atomoxetine), were injected through the tail vein of Swiss Webster mice 30 minutes before intravenous (iv) administration of [(18)F]FDG. The mice were placed on the PET/CT bed for 30 min PET acquisition followed by 10 min CT acquisition for attenuation correction and anatomical delineation of PET images. RESULTS Activated interscapular (IBAT), cervical, periaortic and intercostal BAT were observed in 3-dimentional analysis of [(18)F]FDG PET images. CL 316243 increased the total [(18)F]FDG standard uptake value (SUV) of IBAT 5-fold greater compared to that in placebo-treated mice. It also increased the [(18)F]FDG SUV of white adipose tissue (2.4-fold), and muscle (2.7-fold), as compared to the control. There was no significant difference in heart, brain, spleen and liver uptakes between groups. Forskolin increased [(18)F]FDG SUV of IBAT 1.9-fold greater than that in placebo-treated mice. It also increased the [(18)F]FDG SUV of white adipose tissue (2.2-fold) and heart (5.4-fold) compared to control. There was no significant difference in muscle, brain, spleen, and liver uptakes between groups. Atomoxetine increased [(18)F]FDG SUV of IBAT 1.7-fold greater than that in placebo-treated mice. There were no significant differences in all other organs compared to placebo-treated mice except liver (1.6 fold increase). A positive correlation between SUV levels of IBAT and CT Hounsfield unit (HU) (R(2)=0.55, p<0.001) and between CT HU levels of IBAT and liver (R(2)=0.69, p<0.006) was observed. CONCLUSIONS The three pharmacologic approaches reported here enhanced BAT metabolism by targeting different sites in adrenergic system as measured by [(18)F]FDG PET/CT.
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Affiliation(s)
- M Reza Mirbolooki
- Preclinical Imaging, Department of Radiological Sciences, Medical Sciences B-138, University of California, Irvine, CA 92697-5000, USA
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Abegg K, Schiesser M, Lutz TA, Bueter M. Acute peripheral GLP-1 receptor agonism or antagonism does not alter energy expenditure in rats after Roux-en-Y gastric bypass. Physiol Behav 2013; 121:70-8. [PMID: 23562866 DOI: 10.1016/j.physbeh.2013.03.027] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 02/20/2013] [Accepted: 03/06/2013] [Indexed: 12/28/2022]
Abstract
Compared to traditional weight loss strategies, the compensatory decrease in energy expenditure in response to body weight loss is markedly attenuated after Roux-en-Y gastric bypass surgery (RYGB). Because basal and postprandial levels of glucagon-like peptide-1 (GLP-1) are increased after RYGB surgery, and because GLP-1 has been shown to increase energy expenditure, we investigated if increased GLP-1 levels are involved in the alterations in energy expenditure after RYGB. Adult male Wistar rats were randomized for RYGB (n=8) or sham surgery (n=17). Part of the sham-operated rats were food restricted and body weight-matched (n=8) to the RYGB animals. The effects of acute subcutaneous administration of the GLP-1 antagonist Exendin (9-39) (Ex-9, 30μg/kg) or the GLP-1 agonist Exendin-4 (Ex-4, 5μg/kg), respectively, on energy expenditure were tested using indirect calorimetry. We found that Ex-9 increased food intake in RYGB, but not in sham-operated rats. Energy expenditure was lower in RYGB and sham-operated body weight-matched rats compared to sham-operated ad libitum fed rats, but significantly higher in RYGB rats compared to sham-operated body weight-matched rats. There was no effect of Ex-9 treatment on energy expenditure in either group of animals. Similarly, Ex-4 decreased food intake more in RYGB than in sham-operated rats, but Ex-4 did not modulate energy expenditure in any surgical group. We conclude that acute modulation of GLP-1 signaling is not directly involved in altered energy expenditure after RYGB surgery in rats.
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Affiliation(s)
- Kathrin Abegg
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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Pasanisi F, Pace L, Fonti R, Marra M, Sgambati D, De Caprio C, De Filippo E, Vaccaro A, Salvatore M, Contaldo F. Evidence of brown fat activity in constitutional leanness. J Clin Endocrinol Metab 2013; 98:1214-8. [PMID: 23393181 DOI: 10.1210/jc.2012-2981] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Brown adipose tissue (BAT) was considered essentially nonexistent in adults until recent evidence obtained using 18-fluorodeoxyglucose (18-FDG) positron emission tomography/computed tomography. It seems to play a role in whole body metabolism, but it has not been evaluated in underweight conditions, such as in young females with constitutional leanness (CL) or anorexia nervosa (AN). SUBJECTS AND METHODS Thirty-eight subjects were evaluated from October 2011 to March 2012 : 7 CL (21.7 ± 3.6 y, body mass index [BMI] 16.2 ± 1.0 kg/m(2)), 7 AN (23.4 ± 4.5 y, BMI 15.5 ± 0.8), 3 of the 7 AN after stable refeeding (R-AN, 21.3 ± 1.5 y, BMI 18.8 ± 1.1), and 24 normal weight (NW) women (25.6 ± 3.9 y, BMI 22.2 ± 1.5). Fasting resting metabolic rate and respiratory quotient were measured by indirect calorimetry, body composition by bioimpedentiometry (only in CL, AN, and refed AN), and BAT activity by 18-FDG positron emission tomography/computed tomography scan, all in standardized conditions. RESULTS All CL (100%), none of the AN and refed AN (0%), and 3 of the 24 NW (12%) subjects showed FDG uptake. Average FDG maximum standardized uptake value was 11.4 + 6.7 g/mL in CL and 5.5 ± 1.2 g/mL (min 3.7, max 8.3) in the 3 NW subjects. In CL, the maximum standardized uptake value was directly correlated to resting metabolic rate, corrected for fat-free mass, and inversely correlated with respiratory quotient. CONCLUSION BAT activity has been shown in CL in resting thermoneutral conditions and may exert a role against adipose tissue deposition.
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Affiliation(s)
- Fabrizio Pasanisi
- Federico II University of Naples, Department of Clinical Medicine and Surgery, Via Pansini 5, Naples, Italy.
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Birerdinc A, Jarrar M, Stotish T, Randhawa M, Baranova A. Manipulating molecular switches in brown adipocytes and their precursors: a therapeutic potential. Prog Lipid Res 2012; 52:51-61. [PMID: 22960032 DOI: 10.1016/j.plipres.2012.08.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Revised: 03/28/2012] [Accepted: 08/11/2012] [Indexed: 01/07/2023]
Abstract
Brown adipocytes constitute a metabolically active tissue responsible for non-shivering thermogenesis and the depletion of excess calories. Differentiation of brown fat adipocytes de novo or stimulation of pre-existing brown adipocytes within white adipose depots could provide a novel method for reducing the obesity and alleviating the consequences of type II diabetes worldwide. In this review, we addressed several molecular mechanisms involved in the control of brown fat activity, namely, the β₃-adrenergic stimulation of thermogenesis during exposure to cold or by catecholamines; the augmentation of thyroid function; the modulation of peroxisome proliferator-activated receptor gamma (PPARγ), transcription factors of the C/EBP family, and the PPARγ co-activator PRDM16; the COX-2-driven expression of UCP1; the stimulation of the vanilloid subfamily receptor TRPV1 by capsaicin and monoacylglycerols; the effects of BMP7 or its analogs; the cannabinoid receptor antagonists and melanogenesis modulating agents. Manipulating one or more of these pathways may provide a solution to the problem of harnessing brown fat's thermogenic potential. However, a better understanding of their interplay and other homeostatic mechanisms is required for the development of novel therapies for millions of obese and/or diabetic individuals.
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Affiliation(s)
- Aybike Birerdinc
- Center for the Study of Chronic Metabolic Diseases, School of Systems Biology, College of Science, George Mason University, Fairfax, VA, USA
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Yilmaz Y. Review article: fructose in non-alcoholic fatty liver disease. Aliment Pharmacol Ther 2012; 35:1135-44. [PMID: 22469071 DOI: 10.1111/j.1365-2036.2012.05080.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 02/22/2012] [Accepted: 03/09/2012] [Indexed: 12/15/2022]
Abstract
BACKGROUND The role of excess fructose intake in the pathogenesis of non-alcoholic fatty liver disease (NAFLD) has recently received increasing attention, but the pathophysiology of this relationship has been only partly elucidated. AIM To provide an overview of the potential role played by fructose in the pathogenesis of NAFLD by focusing on both indirect and direct harmful effects. METHODS Experimental and clinical studies which investigated the relation of fructose with NAFLD are reviewed. RESULTS Several factors may potentially contribute to fructose-induced NAFLD, including the induction of the metabolic syndrome, copper deficiency, bacterial translocation from the gut to the liver, the formation of advanced glycation endproducts and a direct dysmetabolic effect on liver enzymes. CONCLUSIONS Experimentally-increased fructose intake recapitulates many of the pathophysiological characteristics of the metabolic syndrome in humans, which may in turn lead to NAFLD. However, the majority of experimental studies tend to involve feeding excessively high levels of fructose (60-70% of total energy intake) which is not reflective of average human intake. Hopefully, the combination of in vivo, in vitro and genetic research will provide substantial mechanistic evidence into the role of fructose in NAFLD development and its complications.
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Affiliation(s)
- Y Yilmaz
- Institute of Gastroenterology, Marmara University, Istanbul, Turkey.
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Betz MJ, Enerbäck S. Therapeutic prospects of metabolically active brown adipose tissue in humans. Front Endocrinol (Lausanne) 2011; 2:86. [PMID: 22649390 PMCID: PMC3355987 DOI: 10.3389/fendo.2011.00086] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 11/12/2011] [Indexed: 12/23/2022] Open
Abstract
The world-wide obesity epidemic constitutes a severe threat to human health and wellbeing and poses a major challenge to health-care systems. Current therapeutic approaches, relying mainly on reduced energy intake and/or increased exercise energy expenditure, are generally of limited effectiveness. Previously believed to be present only in children, the existence of metabolically active brown adipose tissue (BAT) was recently demonstrated also in healthy human adults. The physiological role of BAT is to dissipate chemical energy, mainly from fatty acids, as heat to maintain body temperature in cold environments. Recent studies indicate that the activity of BAT is negatively correlated with overweight and obesity, findings that raise the exciting possibility of new and effective weight reduction therapies based on increased BAT energy expenditure, a process likely to be amenable to pharmacological intervention.
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Affiliation(s)
- Matthias J. Betz
- Department of Medical Genetics, Institute of Biomedicine, Sahlgrenska Academy, University of GöteborgGöteborg, Sweden
- Medizinische Klinik, Campus Innenstadt, Klinikum der Ludwig-Maximilians-Universität MünchenMunich, Germany
| | - Sven Enerbäck
- Department of Medical Genetics, Institute of Biomedicine, Sahlgrenska Academy, University of GöteborgGöteborg, Sweden
- *Correspondence: Sven Enerbäck, Department of Medical Genetics, Institute of Biomedicine, Sahlgrenska Academy, University of Göteborg, Medicinaregatan 9A, Box 440, Göteborg 40530, Sweden. e-mail:
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