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Zhang X, Li Z, Hu R, Liu X, Yang W, Wu Y, Zhang L, Zeng X, Chen R, Liu C, Sun Q. Exposure memory and susceptibility to ambient PM 2.5: A perspective from hepatic cholesterol and bile acid metabolism. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 280:116589. [PMID: 38878334 DOI: 10.1016/j.ecoenv.2024.116589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 05/07/2024] [Accepted: 06/10/2024] [Indexed: 06/25/2024]
Abstract
Both epidemiological and experimental studies increasingly show that exposure to ambient fine particulate matter (PM2.5) is related to the occurrence and development of chronic diseases, such as metabolic diseases. However, whether PM2.5 has "exposure memory" and how these memories affect chronic disease development like hepatic metabolic homeostasis are unknown. Therefore, we aimed to explore the effects of exposure transition on liver cholesterol and bile acids (BAs) metabolism in mice. In this study, C57BL/6 mice were exposed to concentrated ambient PM2.5 or filtered air (FA) in a whole-body exposure facility for an initial period of 10 weeks, followed by another 8 weeks of exposure switch (PM2.5 to FA and FA to PM2.5) comparing to non-switch groups (FA to FA and PM2.5 to PM2.5), which were finally divided into four groups (FF of FA to FA, PP of PM2.5 to PM2.5, PF of PM2.5 to FA, and FP of FA to PM2.5). Our results showed no significant difference in food intake, body composition, glucose homeostasis, and lipid metabolism between FA and PM2.5 groups after the initial exposure before the exposure switch. At the end of the exposure switch, the mice switched from FA to PM2.5 exposure exhibited a high sensitivity to late-onset PM2.5 exposure, as indicated by significantly elevated hepatic cholesterol levels and disturbed BAs metabolism. However, the mice switched from PM2.5 to FA exposure retained a certain memorial effects of previous PM2.5 exposure in hepatic cholesterol levels, cholesterol metabolism, and BAs metabolism. Furthermore, 18-week PM2.5 exposure significantly increased hepatic free BAs levels, which were completely reversed by the FA exposure switch. Finally, the changes in small heterodimeric partner (SHP) and nuclear receptor subfamily 5 group A member 2 (LRH1) in response to exposure switch mechanistically explained the above alterations. Therefore, mice switching from PM2.5 exposure to FA showed only a weak memory of prior PM2.5 exposure. In contrast, the early FA caused mice to be more susceptible to subsequent PM2.5 exposure.
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Affiliation(s)
- Xingjia Zhang
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China
| | - Zixin Li
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China
| | - Renjie Hu
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China
| | - Xiyu Liu
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China
| | - Wenwen Yang
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China
| | - Yue Wu
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China
| | - Lina Zhang
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China
| | - Xiang Zeng
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China
| | - Rucheng Chen
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China
| | - Cuiqing Liu
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China
| | - Qinghua Sun
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China.
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Hu R, Zhang L, Qin L, Ding H, Li R, Gu W, Chen R, Zhang Y, Rajagoplan S, Zhang K, Sun Q, Liu C. Airborne PM 2.5 pollution: A double-edged sword modulating hepatic lipid metabolism in middle-aged male mice. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 324:121347. [PMID: 36858098 DOI: 10.1016/j.envpol.2023.121347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 02/19/2023] [Accepted: 02/22/2023] [Indexed: 06/18/2023]
Abstract
Emerging evidence suggests that exposure to airborne fine particulate matter (PM2.5) is closely related to disturbances in hepatic lipid metabolism. However, no systematic study assessed the age vulnerability in effects of PM2.5 exposure on metabolism, and the potential mechanisms remain unknown. This study aimed to investigate the metabolic susceptibility of different life stages to PM2.5 exposure, and to evaluate the underlying molecular mechanisms. Male C57BL/6 mice at three life phases (young, adult, and middle-aged) were exposed simultaneously to concentrated ambient PM2.5 or filtered air (FA) for 8 weeks using a whole-body inhalational exposure system. The average daily PM2.5 concentrations to which mice were actually exposed were 90.71 ± 7.99 μg/m3. The body weight, total food utilization, body composition, glucose metabolic homeostasis of the mice were evaluated. At euthanasia, serum and liver samples were collected to measure lipid profiles and hepatic function. H&E and Oil Red O staining were used to assess the liver cellular structure and hepatic lipid deposition. Transcriptomics and lipidomics were performed to determine the differentially expressed genes and lipid metabolites in the liver. Quantitative RT-PCR and immunoblots were performed to verify the transcriptomics and explore the mechanism for metabolic susceptibility. PM2.5 exposure led to reductions in body weight gain, total food utilization, and fat mass in middle-aged mice but not in young or adults. Exposure to PM2.5 reduced hepatic lipid deposition by enhancing lipolysis and inhibiting the glycerol-3-phosphate (G3P) pathway of hepatic lipogenesis. Furthermore, PM2.5 exposure attenuated hepatic fatty acid metabolism and primary bile acid biosynthesis. Finally, PM2.5 exposure dysregulated hepatic phospholipid metabolism, as evidenced by increased glycerophospholipid synthesis and disturbed sphingolipid metabolism. Therefore, middle-aged male mice were more vulnerable to PM2.5 exposure with double-edged effects, improved metabolism and hepatic TG accumulation but inhibited hepatic fatty acid and bile acid metabolism and dysregulated phospholipid metabolism.
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Affiliation(s)
- Renjie Hu
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China.
| | - Lu Zhang
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China.
| | - Li Qin
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China.
| | - Hao Ding
- Eco-Environmental Science Research and Design Institute of Zhejiang Province, Hangzhou, Zhejiang, China.
| | - Ran Li
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China.
| | - Weijia Gu
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China.
| | - Rucheng Chen
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China.
| | - Yunhui Zhang
- Key Laboratory of Public Health Safety, Ministry of Education, School of Public Health, Fudan University, Shanghai, 200032, China.
| | - Sanjay Rajagoplan
- Harrington Heart and Vascular Institute, University Hospital Cleveland Medical Center, Cleveland, OH, USA.
| | - Kezhong Zhang
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI, USA.
| | - Qinghua Sun
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China.
| | - Cuiqing Liu
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China; Zhejiang International Science and Technology Cooperation Base of Air Pollution and Health, Hangzhou, Zhejiang, China.
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3
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Exercise reduced the formation of new adipocytes in the adipose tissue of mice in vivo. PLoS One 2021; 16:e0244804. [PMID: 33471817 PMCID: PMC7817033 DOI: 10.1371/journal.pone.0244804] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 12/16/2020] [Indexed: 12/20/2022] Open
Abstract
Exercise has beneficial effects on metabolism and health. Although the skeletal muscle has been a primary focus, exercise also mediates robust adaptations in white adipose tissue. To determine if exercise affects in vivo adipocyte formation, fifty-two, sixteen-week-old C57BL/6J mice were allowed access to unlocked running wheels [Exercise (EX) group; n = 13 males, n = 13 females] or to locked wheels [Sedentary (SED) group; n = 13 males, n = 13 females] for 4-weeks. In vivo adipocyte formation was assessed by the incorporation of deuterium (2H) into the DNA of newly formed adipocytes in the inguinal and gonadal adipose depots. A two-way ANOVA revealed that exercise significantly decreased new adipocyte formation in the adipose tissue of mice in the EX group relative to the SED group (activity effect; P = 0.02). This reduction was observed in male and female mice (activity effect; P = 0.03). Independent analysis of the depots showed a significant reduction in adipocyte formation in the inguinal (P = 0.05) but not in the gonadal (P = 0.18) of the EX group. We report for the first time that exercise significantly reduced in vivo adipocyte formation in the adipose tissue of EX mice using a physiologic metabolic 2H2O-labeling protocol.
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Morla L, Shore O, Lynch IJ, Merritt ME, Wingo CS. A noninvasive method to study the evolution of extracellular fluid volume in mice using time-domain nuclear magnetic resonance. Am J Physiol Renal Physiol 2020; 319:F115-F124. [PMID: 32475134 DOI: 10.1152/ajprenal.00377.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Maintaining water homeostasis is fundamental for cellular function. Many diseases and drugs affect water balance and plasma osmolality. Water homeostasis studies in small animals require the use of invasive or terminal methods that make intracellular fluid volume and extracellular fluid volume (ECF) monitoring over time stressful and time consuming. We examined the feasibility of monitoring mouse ECF by a noninvasive method using time-domain nuclear magnetic resonance (TD-NMR). This technique allows differentiation of protons in a liquid environment (free fluid) from protons in soft tissues containing a majority of either small molecules (lean) or large molecules (fat). Moreover, this apparatus enables rapid, noninvasive, and repeated measurements on the same animal. We assessed the feasibility of coupling TD-NMR analysis to a longitudinal metabolic cage study by monitoring mice daily. We determined the effect of 24-h water deprivation on mouse body parameters and detected a sequential and overlapping decrease in free fluid and lean mass during water deprivation. Finally, we studied the effect of mineralocorticoids that are known to induce a transient increase in ECF but for which no direct measurements have been performed in mice. We showed, for the first time, that mineralocorticoids induced a transient ~15% increase in free fluid in conscious mice. TD-NMR is, therefore, the first method to allow direct measurement of discrete changes in ECF in conscious small animals. This method allows analysis of kinetic changes to stimuli before investigating with terminal methods and will allow further understanding of fluid disorders.
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Affiliation(s)
- Luciana Morla
- Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale, Sorbonne Université, USPC, Université Paris Descartes, Université Paris Diderot, Paris, France.,Centre National de la Recherche Scientifique, ERL 8228, Laboratoire de Physiologie Rénale et Tubulopathies, Paris, France
| | - Oliver Shore
- North Florida/South Georgia Veterans Health System, Gainesville, Florida.,Department of Medicine, University of Florida, Gainesville, Florida
| | - I Jeanette Lynch
- North Florida/South Georgia Veterans Health System, Gainesville, Florida.,Department of Medicine, University of Florida, Gainesville, Florida
| | - Matthew E Merritt
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida
| | - Charles S Wingo
- North Florida/South Georgia Veterans Health System, Gainesville, Florida.,Department of Medicine, University of Florida, Gainesville, Florida
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5
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Onufer EJ, Han YH, Czepielewski RS, Courtney CM, Sutton S, Randolph GJ, Warner BW. Effects of high-fat diet on liver injury after small bowel resection. J Pediatr Surg 2020; 55:1099-1106. [PMID: 32164985 PMCID: PMC7299751 DOI: 10.1016/j.jpedsurg.2020.02.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 02/20/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND The optimal regimen for enteral nutritional support in the management of children with short bowel syndrome (SBS) is not well characterized. A high fat, enteral diet is theoretically beneficial due to increased caloric density and enhanced structural adaptation. We therefore sought to determine the long-term effects of a high fat diet (HFD) on liver injury, a common complication of SBS, compared to a standard chow (SC) diet. METHODS Using a parenteral nutrition-independent model of resection-associated liver injury, C57BL/6 mice underwent a sham operation or a 50% or 75% proximal small bowel resection (SBR). Mice in each group were then fed either a HFD (35% kcal fat) or SC (13% kcal fat). At post-operative week 15, markers of liver injury were quantified. RESULTS Liver triglyceride levels were increased from 7- to 19-fold in mice on the HFD compared to mice fed SC in the sham, 50%, and 75% resection groups. Serum ALT (2.2-fold increase in 75% resected mice compared to sham controls) and AST (2.0- and 2.7-fold increases in 50% and 75% resected mice, respectively) levels as well as fibrotic liver staining were elevated only in resected mice fed a HFD. CONCLUSION Long-term enteral feeding of HFD in our murine SBS model is associated with hepatic steatosis and liver injury. Our observation that liver steatosis and injury occur independent of parenteral nutrition suggests that enteral feeding composition and magnitude of intestinal loss may make a significant contribution to intestinal failure-associated liver disease.
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Affiliation(s)
- Emily J. Onufer
- Division of Pediatric Surgery, Department of Surgery, St. Louis Children’s Hospital, Washington University in St. Louis School of Medicine, St. Louis, MO
| | - Yong-Hyun Han
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO
| | - Rafael S. Czepielewski
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO
| | - Cathleen M. Courtney
- Division of Pediatric Surgery, Department of Surgery, St. Louis Children’s Hospital, Washington University in St. Louis School of Medicine, St. Louis, MO
| | - Stephanie Sutton
- Division of Pediatric Surgery, Department of Surgery, St. Louis Children’s Hospital, Washington University in St. Louis School of Medicine, St. Louis, MO
| | - Gwendalyn J. Randolph
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO
| | - Brad W. Warner
- Division of Pediatric Surgery, Department of Surgery, St. Louis Children’s Hospital, Washington University in St. Louis School of Medicine, St. Louis, MO
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6
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Disser NP, Ghahramani GC, Swanson JB, Wada S, Chao ML, Rodeo SA, Oliver DJ, Mendias CL. Widespread diversity in the transcriptomes of functionally divergent limb tendons. J Physiol 2020; 598:1537-1550. [PMID: 32083717 DOI: 10.1113/jp279646] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 02/20/2020] [Indexed: 12/23/2022] Open
Abstract
KEY POINTS Tendon is a hypocellular, matrix-rich tissue that has been excluded from comparative transcriptional atlases. These atlases have provided important knowledge about biological heterogeneity between tissues, and our study addresses this important gap. We performed measures on four of the most studied tendons, the Achilles, forepaw flexor, patellar and supraspinatus tendons of both mice and rats. These tendons are functionally distinct and are also among the most commonly injured, and therefore of important translational interest. Approximately one-third of the filtered transcriptome was differentially regulated between Achilles, forepaw flexor, patellar and supraspinatus tendons within either mice or rats. Nearly two-thirds of the transcripts that are expressed in anatomically similar tendons were different between mice and rats. The overall findings from this study identified that although tendons across the body share a common anatomical definition based on their physical location between skeletal muscle and bone, tendon is a surprisingly genetically heterogeneous tissue. ABSTRACT Tendon is a functionally important connective tissue that transmits force between skeletal muscle and bone. Previous studies have evaluated the architectural designs and mechanical properties of different tendons throughout the body. However, less is known about the underlying transcriptional differences between tendons that may dictate their designs and properties. Therefore, our objective was to develop a comprehensive atlas of the transcriptome of limb tendons in adult mice and rats using systems biology techniques. We selected the Achilles, forepaw digit flexor, patellar, and supraspinatus tendons due to their divergent functions and high rates of injury and tendinopathies in patients. Using RNA sequencing data, we generated the Comparative Tendon Transcriptional Database (CTTDb) that identified substantial diversity in the transcriptomes of tendons both within and across species. Approximately 30% of filtered transcripts were differentially regulated between tendons of a given species, and nearly 60% of the filtered transcripts present in anatomically similar tendons were different between species. Many of the genes that differed between tendons and across species are important in tissue specification and limb morphogenesis, tendon cell biology and tenogenesis, growth factor signalling, and production and maintenance of the extracellular matrix. This study indicates that tendon is a surprisingly heterogenous tissue with substantial genetic variation based on anatomical location and species.
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Affiliation(s)
| | - Gregory C Ghahramani
- Hospital for Special Surgery, New York, NY, USA.,Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA
| | | | - Susumu Wada
- Hospital for Special Surgery, New York, NY, USA
| | - Max L Chao
- Hospital for Special Surgery, New York, NY, USA
| | | | | | - Christopher L Mendias
- Hospital for Special Surgery, New York, NY, USA.,Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA
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7
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Minaya DM, Di Lorenzo PM, Hajnal A, Czaja K. Roux-en-Y gastric bypass surgery triggers rapid DNA fragmentation in vagal afferent neurons in rats. Acta Neurobiol Exp (Wars) 2020. [DOI: 10.21307/ane-2019-040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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8
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Xiao D, Balcom BJ. Ultra-short echo time imaging with multiple echo refocusing for porous media T 2 mapping. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 299:33-41. [PMID: 30554042 DOI: 10.1016/j.jmr.2018.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 12/01/2018] [Accepted: 12/04/2018] [Indexed: 05/21/2023]
Abstract
T2 relaxation time measurement is a powerful tool to distinguish signal components in porous media. As T2 weighting is generally achieved by spin-echo based methods, it is very challenging to capture very short T2 relaxation time components, approximately 1 ms, with high resolution spatial encoding. It is especially challenging when T2 relaxation times of the other signal components are not known a priori. We propose a method, combining ultrashort echo time (UTE) imaging with multiple spin echo refocusing, to generate a series of images with T2 weighting. The T2 decay curves for each image voxel were extracted, and multiple T2 relaxation components were quantitatively evaluated. The method has been applied to a fast relaxation system, namely, moisture content in wood samples to differentiate cell wall (bound) water and cell cavity (lumen) water.
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Affiliation(s)
- Dan Xiao
- Department of Physics, University of Windsor, 401 Sunset Avenue, Windsor, ON N9B 3P4, Canada; MRI Research Center, Department of Physics, University of New Brunswick, 8 Bailey Drive, Fredericton, NB E3B 5A3, Canada.
| | - Bruce J Balcom
- MRI Research Center, Department of Physics, University of New Brunswick, 8 Bailey Drive, Fredericton, NB E3B 5A3, Canada.
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9
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Sen T, Cawthon CR, Ihde BT, Hajnal A, DiLorenzo PM, de La Serre CB, Czaja K. Diet-driven microbiota dysbiosis is associated with vagal remodeling and obesity. Physiol Behav 2017; 173:305-317. [PMID: 28249783 DOI: 10.1016/j.physbeh.2017.02.027] [Citation(s) in RCA: 168] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 01/27/2017] [Accepted: 02/22/2017] [Indexed: 02/06/2023]
Abstract
Obesity is one of the major health issues in the United States. Consumption of diets rich in energy, notably from fats and sugars (high-fat/high-sugar diet: HF/HSD) is linked to the development of obesity and a popular dietary approach for weight loss is to reduce fat intake. Obesity research traditionally uses low and high fat diets and there has been limited investigation of the potential detrimental effects of a low-fat/high-sugar diet (LF/HSD) on body fat accumulation and health. Therefore, in the present study, we investigated the effects of HF/HSD and LF/HSD on microbiota composition, gut inflammation, gut-brain vagal communication and body fat accumulation. Specifically, we tested the hypothesis that LF/HSD changes the gut microbiota, induces gut inflammation and alters vagal gut-brain communication, associated with increased body fat accumulation. Sprague-Dawley rats were fed an HF/HSD, LF/HSD or control low-fat/low-sugar diet (LF/LSD) for 4weeks. Body weight, caloric intake, and body composition were monitored daily and fecal samples were collected at baseline, 1, 6 and 27days after the dietary switch. After four weeks, blood and tissues (gut, brain, liver and nodose ganglia) were sampled. Both HF/HSD and LF/HSD-fed rats displayed significant increases in body weight and body fat compared to LF/LSD-fed rats. 16S rRNA sequencing showed that both HF/HSD and LF/HSD-fed animals exhibited gut microbiota dysbiosis characterized by an overall decrease in bacterial diversity and an increase in Firmicutes/Bacteriodetes ratio. Dysbiosis was typified by a bloom in Clostridia and Bacilli and a marked decrease in Lactobacillus spp. LF/HSD-fed animals showed a specific increase in Sutterella and Bilophila, both Proteobacteria, abundances of which have been associated with liver damage. Expression of pro-inflammatory cytokines, such as IL-6, IL-1β and TNFα, was upregulated in the cecum while levels of tight junction protein occludin were downregulated in both HF/HSD and LF/HSD fed rats. HF/HSD and LF/HSD-fed rats also exhibited an increase in cecum and serum levels of lipopolysaccharide (LPS), a pro-inflammatory bacterial product. Immunofluorescence revealed the withdrawal of vagal afferents from the gut and at their site of termination the nucleus of the solitary tract (NTS) in both the HF/HSD and LF/HSD rats. Moreover, there was significant microglia activation in the nodose ganglia, which contain the vagal afferent neuron cell bodies, of HF/HSD and LF/HSD rats. Taken together, these data indicate that, similar to HF/HSD, consumption of an LF/HSD induces dysbiosis of gut microbiota, increases gut inflammation and alters vagal gut-brain communication. These changes are associated with an increase in body fat accumulation.
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Affiliation(s)
- Tanusree Sen
- Department of Veterinary Biosciences & Diagnostic Imaging, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, United States
| | - Carolina R Cawthon
- Department of Foods and Nutrition, College of Family and Consumer Sciences, University of Georgia, Athens, GA 30602, United States
| | - Benjamin Thomas Ihde
- Department of Veterinary Biosciences & Diagnostic Imaging, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, United States
| | - Andras Hajnal
- The Pennsylvania State University, College of Medicine, Neural and Behavioral Sciences, Hershey, PA 17033, United States
| | | | - Claire B de La Serre
- Department of Foods and Nutrition, College of Family and Consumer Sciences, University of Georgia, Athens, GA 30602, United States.
| | - Krzysztof Czaja
- Department of Veterinary Biosciences & Diagnostic Imaging, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, United States.
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10
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Caplan SL, Zheng B, Dawson-Scully K, White CA, West LM. Pseudopterosin A: Protection of Synaptic Function and Potential as a Neuromodulatory Agent. Mar Drugs 2016; 14:md14030055. [PMID: 26978375 PMCID: PMC4820309 DOI: 10.3390/md14030055] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 02/28/2016] [Accepted: 03/04/2016] [Indexed: 01/07/2023] Open
Abstract
Natural products have provided an invaluable source of inspiration in the drug discovery pipeline. The oceans are a vast source of biological and chemical diversity. Recently, this untapped resource has been gaining attention in the search for novel structures and development of new classes of therapeutic agents. Pseudopterosins are group of marine diterpene glycosides that possess an array of potent biological activities in several therapeutic areas. Few studies have examined pseudopterosin effects during cellular stress and, to our knowledge, no studies have explored their ability to protect synaptic function. The present study probes pseudopterosin A (PsA) for its neuromodulatory properties during oxidative stress using the fruit fly, Drosophila melanogaster. We demonstrate that oxidative stress rapidly reduces neuronal activity, resulting in the loss of neurotransmission at a well-characterized invertebrate synapse. PsA mitigates this effect and promotes functional tolerance during oxidative stress by prolonging synaptic transmission in a mechanism that differs from scavenging activity. Furthermore, the distribution of PsA within mammalian biological tissues following single intravenous injection was investigated using a validated bioanalytical method. Comparable exposure of PsA in the mouse brain and plasma indicated good distribution of PsA in the brain, suggesting its potential as a novel neuromodulatory agent.
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Affiliation(s)
- Stacee Lee Caplan
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA.
| | - Bo Zheng
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, The University of Georgia, Athens, GA 30602, USA.
| | - Ken Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA.
| | - Catherine A White
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, The University of Georgia, Athens, GA 30602, USA.
| | - Lyndon M West
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, The University of Georgia, Athens, GA 30602, USA.
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL 33431, USA.
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11
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Mumphrey MB, Hao Z, Townsend RL, Patterson LM, Berthoud HR. Sleeve Gastrectomy Does Not Cause Hypertrophy and Reprogramming of Intestinal Glucose Metabolism in Rats. Obes Surg 2016; 25:1468-73. [PMID: 25566744 DOI: 10.1007/s11695-014-1547-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Clinical studies have shown similar rapid improvements in body mass and glycemic control after Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG). Evidence suggests that adaptive intestinal tissue growth and reprogramming of intestinal glucose disposal play a key role in the beneficial effects on glucose homeostasis after RYGB, but it is not known whether such adaptive changes also occur after sleeve gastrectomy. METHODS High-fat diet-induced obese rats were subjected to either VSG or RYGB, and intestinal growth and functional adaptations were assessed by using morphometric, immunohistochemical, and immuno-blot techniques, 3 months after surgery or sham surgery. RESULTS The cross-sectional areas of the Roux and common limbs are significantly increased after RYGB compared with sham surgery (Roux limb: 17.1 ± 4.0 vs. 5.5 ± 0.1 mm(2); common limb: 11.7 ± 0.6 vs. 5.1 ± 0.5 mm(2); p < 0.01), but the cross-sectional area of the corresponding jejunum is not different from controls after VSG. Similarly, mucosal thickness and the number of GLP-1 cells are not increased after VSG. Protein expression of hexokinase II is increased fourfold (p < 0.01) in the Roux limb after RYGB, but not in the jejunum after VSG. CONCLUSIONS Adaptive hypertrophy and reprogramming of glucose metabolism in the small intestine are not necessary for VSG to improve body composition and glycemic control. The similar beneficial effects of VSG and RYGB on glucose homeostasis might be mediated by different mechanisms.
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Affiliation(s)
- Michael B Mumphrey
- Neurobiology of Nutrition Laboratory, Pennington Biomedical Research Center, Louisiana State University System, 6400 Perkins Road, Baton Rouge, LA, 70808, USA
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Raab S, Wang H, Uhles S, Cole N, Alvarez-Sanchez R, Künnecke B, Ullmer C, Matile H, Bedoucha M, Norcross RD, Ottaway-Parker N, Perez-Tilve D, Conde Knape K, Tschöp MH, Hoener MC, Sewing S. Incretin-like effects of small molecule trace amine-associated receptor 1 agonists. Mol Metab 2015; 5:47-56. [PMID: 26844206 PMCID: PMC4703809 DOI: 10.1016/j.molmet.2015.09.015] [Citation(s) in RCA: 70] [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: 08/26/2015] [Revised: 09/21/2015] [Accepted: 09/22/2015] [Indexed: 12/05/2022] Open
Abstract
Objective Type 2 diabetes and obesity are emerging pandemics in the 21st century creating worldwide urgency for the development of novel and safe therapies. We investigated trace amine-associated receptor 1 (TAAR1) as a novel target contributing to the control of glucose homeostasis and body weight. Methods We investigated the peripheral human tissue distribution of TAAR1 by immunohistochemistry and tested the effect of a small molecule TAAR1 agonist on insulin secretion in vitro using INS1E cells and human islets and on glucose tolerance in C57Bl6, and db/db mice. Body weight effects were investigated in obese DIO mice. Results TAAR1 activation by a selective small molecule agonist increased glucose-dependent insulin secretion in INS1E cells and human islets and elevated plasma PYY and GLP-1 levels in mice. In diabetic db/db mice, the TAAR1 agonist normalized glucose excursion during an oral glucose tolerance test. Sub-chronic treatment of diet-induced obese (DIO) mice with the TAAR1 agonist resulted in reduced food intake and body weight. Furthermore insulin sensitivity was improved and plasma triglyceride levels and liver triglyceride content were lower than in controls. Conclusions We have identified TAAR1 as a novel integrator of metabolic control, which acts on gastrointestinal and pancreatic islet hormone secretion. Thus TAAR1 qualifies as a novel and promising target for the treatment of type 2 diabetes and obesity. TAAR1 is a novel key player in metabolic control. TAAR1 is expressed in β-cells and intestinal enteroendocrine cells in mice and humans. TAAR1 agonist improved glucose tolerance and reduced body weight in mouse disease models.
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Affiliation(s)
- Susanne Raab
- Roche Pharma Research & Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
| | - Haiyan Wang
- Roche Pharma Research & Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
| | - Sabine Uhles
- Roche Pharma Research & Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
| | - Nadine Cole
- Roche Pharma Research & Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
| | - Ruben Alvarez-Sanchez
- Roche Pharma Research & Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
| | - Basil Künnecke
- Roche Pharma Research & Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
| | - Christoph Ullmer
- Roche Pharma Research & Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
| | - Hugues Matile
- Roche Pharma Research & Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
| | - Marc Bedoucha
- Roche Pharma Research & Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
| | - Roger D Norcross
- Roche Pharma Research & Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
| | - Nickki Ottaway-Parker
- Department of Internal Medicine, Metabolic Disease Institute, University of Cincinnati, Cincinnati, OH 45237, USA
| | - Diego Perez-Tilve
- Department of Internal Medicine, Metabolic Disease Institute, University of Cincinnati, Cincinnati, OH 45237, USA
| | - Karin Conde Knape
- Roche Pharma Research & Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
| | - Matthias H Tschöp
- Helmholtz Diabetes Center, Helmholtz Zentrum München and Division of Metabolic Diseases, Technische Universität München, Germany
| | - Marius C Hoener
- Roche Pharma Research & Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
| | - Sabine Sewing
- Roche Pharma Research & Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
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McCreath KJ, Espada S, Gálvez BG, Benito M, de Molina A, Sepúlveda P, Cervera AM. Targeted disruption of the SUCNR1 metabolic receptor leads to dichotomous effects on obesity. Diabetes 2015; 64:1154-67. [PMID: 25352636 DOI: 10.2337/db14-0346] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A number of metabolites have signaling properties by acting through G-protein-coupled receptors. Succinate, a Krebs cycle intermediate, increases after dysregulated energy metabolism and can bind to its cognate receptor succinate receptor 1 (Sucnr1, or GPR91) to activate downstream signaling pathways. We show that Sucnr1 is highly expressed in the white adipose tissue (WAT) compartment of mice and regulates adipose mass and glucose homeostasis. Sucnr1(-/-) mice were generated, and weight gain was monitored under basal and nutritional stress (high-fat diet [HFD]) conditions. On chow diet, Sucnr1(-/-) mice had increased energy expenditure, were lean with a smaller WAT compartment, and had improved glucose buffering. Lipolysis measurements revealed that Sucnr1(-/-) mice were released from succinate-induced inhibition of lipolysis, demonstrating a function of Sucnr1 in adipose tissue. Sucnr1 deletion also protected mice from obesity on HFD, but only during the initial period; at later stages, body weight of HFD-fed Sucnr1(-/-) mice was almost comparable with wild-type (WT) mice, but WAT content was greater. Also, these mice became progressively hyperglycemic and failed to secrete insulin, although pancreas architecture was similar to WT mice. These findings suggest that Sucnr1 is a sensor for dietary energy and raise the interesting possibility that protocols to modulate Sucnr1 might have therapeutic utility in the setting of obesity.
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Affiliation(s)
- Kenneth J McCreath
- Department of Cardiovascular Development and Repair, Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain
| | - Sandra Espada
- Department of Cardiovascular Development and Repair, Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain
| | - Beatriz G Gálvez
- Department of Cardiovascular Development and Repair, Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain
| | - Marina Benito
- Advanced Imaging Unit, Department of Atherothrombosis, Imaging, and Epidemiology, Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain CIBER de Enfermedades Respiratorias, Madrid, Spain
| | - Antonio de Molina
- Comparative Medicine Unit, Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain
| | - Pilar Sepúlveda
- Regenerative Medicine and Heart Transplantation Unit, Instituto de Investigación Sanitaria La Fe, Valencia, Spain
| | - Ana M Cervera
- Department of Cardiovascular Development and Repair, Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain Regenerative Medicine and Heart Transplantation Unit, Instituto de Investigación Sanitaria La Fe, Valencia, Spain
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Mumphrey MB, Hao Z, Townsend RL, Patterson LM, Morrison CD, Münzberg H, Stylopoulos N, Ye J, Berthoud HR. Reversible hyperphagia and obesity in rats with gastric bypass by central MC3/4R blockade. Obesity (Silver Spring) 2014; 22:1847-53. [PMID: 24799258 PMCID: PMC4114988 DOI: 10.1002/oby.20773] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 03/24/2014] [Accepted: 04/10/2014] [Indexed: 01/06/2023]
Abstract
OBJECTIVE To test the commonly held assumption that gastric bypass surgery lowers body weight because it limits the ability to eat large amounts of food. METHODS Central melanocortin signaling was blocked by ICV infusion of the melanocortin-3/4 receptor antagonist SHU9119 for 14 days in rats whose high-fat diet-induced obesity had been reversed by Roux-en-Y gastric bypass surgery. RESULTS SHU9119 increased daily food intake (+ 100%), body weight (+30%), and fat mass (+50%) in rats with RYGB, surpassing the presurgical body weight and that of saline-treated sham-operated rats. Doubling of food intake was entirely due to increased meal frequency, but not meal size. After termination of SHU9119, body weight promptly returned to near preinfusion levels. In sham-operated rats, SHU9119 produced even larger increases in food intake and body weight. CONCLUSIONS RYGB rats do not settle at a lower level of body weight because they cannot eat more food as they can easily double food intake by increasing meal frequency. The reversible obesity suggests that RYGB rats actively defend the lower body weight. However, because both RYGB and sham-operated rats responded to SHU9119, central melanocortin signaling is not the critical mechanism in RYGB rats responsible for this defense.
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Affiliation(s)
- Michael B. Mumphrey
- Neurobiology of Nutrition Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana 70808
| | - Zheng Hao
- Neurobiology of Nutrition Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana 70808
| | - R. Leigh Townsend
- Neurobiology of Nutrition Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana 70808
| | - Laurel M. Patterson
- Neurobiology of Nutrition Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana 70808
| | - Christopher D. Morrison
- Neurobiology of Nutrition Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana 70808
| | - Heike Münzberg
- Neurobiology of Nutrition Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana 70808
| | - Nicholas Stylopoulos
- Division of Endocrinology, Children’s Hospital Boston, Harvard medical School, Boston, Massachusetts
| | - Jianping Ye
- Neurobiology of Nutrition Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana 70808
| | - Hans-Rudolf Berthoud
- Neurobiology of Nutrition Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana 70808
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Ye J, Hao Z, Mumphrey MB, Townsend RL, Patterson LM, Stylopoulos N, Münzberg H, Morrison CD, Drucker DJ, Berthoud HR. GLP-1 receptor signaling is not required for reduced body weight after RYGB in rodents. Am J Physiol Regul Integr Comp Physiol 2014; 306:R352-62. [PMID: 24430883 DOI: 10.1152/ajpregu.00491.2013] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Exaggerated GLP-1 and PYY secretion is thought to be a major mechanism in the reduced food intake and body weight after Roux-en-Y gastric bypass surgery. Here, we use complementary pharmacological and genetic loss-of-function approaches to test the role of increased signaling by these gut hormones in high-fat diet-induced obese rodents. Chronic brain infusion of a supramaximal dose of the selective GLP-1 receptor antagonist exendin-9-39 into the lateral cerebral ventricle significantly increased food intake and body weight in both RYGB and sham-operated rats, suggesting that, while contributing to the physiological control of food intake and body weight, central GLP-1 receptor signaling tone is not the critical mechanism uniquely responsible for the body weight-lowering effects of RYGB. Central infusion of the selective Y2R-antagonist BIIE0246 had no effect in either group, suggesting that it is not critical for the effects of RYGB on body weight under the conditions tested. In a recently established mouse model of RYGB that closely mimics surgery and weight loss dynamics in humans, obese GLP-1R-deficient mice lost the same amount of body weight and fat mass and maintained similarly lower body weight compared with wild-type mice. Together, the results surprisingly provide no support for important individual roles of either gut hormone in the specific mechanisms by which RYGB rats settle at a lower body weight. It is likely that the beneficial effects of bariatric surgeries are expressed through complex mechanisms that require combination approaches for their identification.
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Affiliation(s)
- Jianping Ye
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana
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16
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Longitudinal assessment of food intake, fecal energy loss, and energy expenditure after Roux-en-Y gastric bypass surgery in high-fat-fed obese rats. Obes Surg 2013; 23:531-40. [PMID: 23269513 DOI: 10.1007/s11695-012-0846-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND The efficacy of Roux-en-Y gastric bypass (RYGB) surgery to produce weight loss has been well-documented, but few studies have measured the key components of energy balance, food intake, and energy expenditure longitudinally. METHODS Male Sprague-Dawley rats on a high-fat diet underwent either RYGB, sham operation, or pair feeding and were compared to chow-fed lean controls. Body weight and composition, food intake and preference, energy expenditure, fecal output, and gastric emptying were monitored before and up to 4 months after intervention. RESULTS Despite the recovery of initially decreased food intake to levels slightly higher than before surgery and comparable to sham-operated rats after about 1 month, RYGB rats maintained a lower level of body weight and fat mass for 4 months that was not different from chow-fed age-matched controls. Energy expenditure corrected for lean body mass at 1 and 4 months after RYGB was not different from presurgical levels and from all other groups. Fecal energy loss was significantly increased at 6 and 16 weeks after RYGB compared to sham operation, and there was a progressive decrease in fat preference after RYGB. CONCLUSIONS In this rat model of RYGB, sustained weight loss is achieved by a combination of initial hypophagia and sustained increases in fecal energy loss, without change in energy expenditure per lean mass. A shift away from high-fat towards low-fat/high-carbohydrate food preference occurring in parallel suggests long-term adaptive mechanisms related to fat absorption.
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Müller HP, Niessen HG, Kaulisch T, Ludolph AC, Kassubek J, Stiller D. MRI allows for longitudinal quantitative analysis of body fat composition in rats: An analysis of sibutramine-associated changes at the group level. Magn Reson Imaging 2013; 31:1150-5. [DOI: 10.1016/j.mri.2013.02.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 01/22/2013] [Accepted: 02/20/2013] [Indexed: 12/25/2022]
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Revel FG, Moreau JL, Pouzet B, Mory R, Bradaia A, Buchy D, Metzler V, Chaboz S, Groebke Zbinden K, Galley G, Norcross RD, Tuerck D, Bruns A, Morairty SR, Kilduff TS, Wallace TL, Risterucci C, Wettstein JG, Hoener MC. A new perspective for schizophrenia: TAAR1 agonists reveal antipsychotic- and antidepressant-like activity, improve cognition and control body weight. Mol Psychiatry 2013; 18:543-56. [PMID: 22641180 DOI: 10.1038/mp.2012.57] [Citation(s) in RCA: 174] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Schizophrenia is a chronic, severe and highly complex mental illness. Current treatments manage the positive symptoms, yet have minimal effects on the negative and cognitive symptoms, two prominent features of the disease with critical impact on the long-term morbidity. In addition, antipsychotic treatments trigger serious side effects that precipitate treatment discontinuation. Here, we show that activation of the trace amine-associated receptor 1 (TAAR1), a modulator of monoaminergic neurotransmission, represents a novel therapeutic option. In rodents, activation of TAAR1 by two novel and pharmacologically distinct compounds, the full agonist RO5256390 and the partial agonist RO5263397, blocks psychostimulant-induced hyperactivity and produces a brain activation pattern reminiscent of the antipsychotic drug olanzapine, suggesting antipsychotic-like properties. TAAR1 agonists do not induce catalepsy or weight gain; RO5263397 even reduced haloperidol-induced catalepsy and prevented olanzapine from increasing body weight and fat accumulation. Finally, TAAR1 activation promotes vigilance in rats and shows pro-cognitive and antidepressant-like properties in rodent and primate models. These data suggest that TAAR1 agonists may provide a novel and differentiated treatment of schizophrenia as compared with current medication standards: TAAR1 agonists may improve not only the positive symptoms but also the negative symptoms and cognitive deficits, without causing adverse effects such as motor impairments or weight gain.
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Affiliation(s)
- F G Revel
- Neuroscience Research, Pharmaceuticals Division, F. Hoffmann-La Roche, Basel, Switzerland
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Cheung WW, Mak RH. Melanocortin antagonism ameliorates muscle wasting and inflammation in chronic kidney disease. Am J Physiol Renal Physiol 2012; 303:F1315-24. [PMID: 22914778 DOI: 10.1152/ajprenal.00341.2012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Aberrant melanocortin signaling has been implicated in the pathogenesis of wasting in chronic kidney disease (CKD). Previously, we demonstrated that agouti-related peptide (AgRP), a melenocortin-4 receptor antagonist, reduced CKD-associated cachexia in CKD mice. Our previous studies with AgRP utilized dual energy X-ray (DXA) densitometry to assess the body composition in mice (Cheung W, Kuo HJ, Markison S, Chen C, Foster AC, Marks DL, Mak RH. J Am Soc Nephrol 18: 2517-2524, 2007; Cheung W, Yu PX, Little BM, Cone RD, Marks DL, Mak RH. J Clin Invest 115: 1659-1665, 2005). DXA is unable to differentiate water content in mice, and fluid retention in CKD may lead to an overestimate of lean mass. In this study, we employed quantitative magnetic resonance technique to evaluate body composition change following central administration of AgRP in a CKD mouse model. AgRP treatment improved energy expenditure, total body mass, fat mass, and lean body mass in CKD mouse. We also investigated the effect of CKD-associated cachexia on the signaling pathways leading to wasting in skeletal muscle, as well as whether these changes can be ameliorated by central administration of AgRP. AgRP treatment caused an overall decrease in proinflammatory cytokines, which may be one important mechanism of its effects. Muscle wasting in CKD may be due to the activation of proteolytic pathways as well as inhibition of myogenesis and muscle regeneration processes. Our results suggest that these aberrant pathological pathways leading to muscle wasting in CKD mice were ameliorated by central administration of AgRP.
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Affiliation(s)
- Wai W Cheung
- Pediatric Nephrology, University of California, San Diego, California, USA
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Vagal innervation of the hepatic portal vein and liver is not necessary for Roux-en-Y gastric bypass surgery-induced hypophagia, weight loss, and hypermetabolism. Ann Surg 2012; 255:294-301. [PMID: 22202582 DOI: 10.1097/sla.0b013e31823e71b7] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE To determine the role of the common hepatic branch of the abdominal vagus on the beneficial effects of Roux-en-Y gastric bypass (RYGB) on weight loss, food intake, food choice, and energy expenditure in a rat model. BACKGROUND Although changes in gut hormone patterns are the leading candidates in RYGB's effects on appetite, weight loss, and reversal of diabetes, a potential role for afferent signaling through the vagal hepatic branch potentially sensing glucose levels in the hepatic portal vein has recently been suggested in a mouse model of RYGB. METHODS Male Sprague-Dawley rats underwent either RYGB alone (RYGB; n = 7), RYGB + common hepatic branch vagotomy (RYGB + HV; n = 6), or sham procedure (sham; n = 9). Body weight, body composition, meal patterns, food choice, energy expenditure, and fecal energy loss were monitored up to 3 months after intervention. RESULTS Both RYGB and RYGB + HV significantly reduced body weight, adiposity, meal size, and fat preference, and increased satiety, energy expenditure, and respiratory exchange rate compared with sham procedure, and there were no significant differences in these effects between RYGB and RYGB + HV rats. CONCLUSIONS Integrity of vagal nerve supply to the liver, hepatic portal vein, and the proximal duodenum provided by the common hepatic branch is not necessary for RYGB to reduce food intake and body weight or increase energy expenditure. Specifically, it is unlikely that a hepatic portal vein glucose sensor signaling RYGB-induced increased intestinal gluconeogenesis to the brain depends on vagal afferent fibers.
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A measure of glucocorticoid load provided by DNA methylation of Fkbp5 in mice. Psychopharmacology (Berl) 2011; 218:303-12. [PMID: 21509501 PMCID: PMC3918452 DOI: 10.1007/s00213-011-2307-3] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 04/05/2011] [Indexed: 10/18/2022]
Abstract
RATIONALE Given the contribution of cortisol dysregulation to neuropsychiatric and metabolic disorders, it is important to be able to accurately compute glucocorticoid burden, a measure of allostatic load. One major problem in calculating cortisol burden is that existing measures reflect cortisol exposure over a short duration and have not been proven to reliably quantify cortisol burden over weeks or months. METHOD We treated two cohorts of mice with corticosterone in the drinking water and determined the relationship between serial plasma corticosterone levels drawn over 4 weeks and the whole-blood DNA methylation (DNAm) changes in a specific glucocorticoid-sensitive gene, Fkbp5, determined at the end of the treatment period. RESULTS We observed that the percent reduction in DNAm in the intron 1 region of Fkbp5 determined from a single blood draw strongly reflected average glucocorticoid burden generated weekly during the prior month of glucocorticoid exposure. There were also strong correlations in DNAm with glucocorticoid-induced end organ changes in spleen weight and visceral fat. We tested a subset of these animals for anxiety-like behavior in the elevated plus maze and found that DNAm in the blood also has predictive value in determining the behavioral consequences of glucocorticoid exposure. CONCLUSION A whole-blood assessment of Fkbp5 gene methylation is a biomarker that integrates 4 weeks of glucocorticoid exposure and may be a useful measure in states of excess exposure. It will be important to determine if Fkbp5 DNAm changes can also be a biomarker of glucocorticoid burden during chronic social stress.
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Shin AC, Townsend RL, Patterson LM, Berthoud HR. "Liking" and "wanting" of sweet and oily food stimuli as affected by high-fat diet-induced obesity, weight loss, leptin, and genetic predisposition. Am J Physiol Regul Integr Comp Physiol 2011; 301:R1267-80. [PMID: 21849633 DOI: 10.1152/ajpregu.00314.2011] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Cross-sectional studies in both humans and animals have demonstrated associations between obesity and altered reward functions at the behavioral and neural level, but it is unclear whether these alterations are cause or consequence of the obese state. Reward behaviors were quantified in male, outbred Sprague-Dawley (SD) and selected line obesity-prone (OP) and obesity-resistant (OR) rats after induction of obesity by high-fat diet feeding and after subsequent loss of excess body weight by chronic calorie restriction. As measured by the brief access lick and taste-reactivity paradigms, both obese SD and OP rats "liked" low concentrations of sucrose and corn oil less, but "liked" the highest concentrations more, compared with lean rats, and this effect was fully reversed by weight loss in SD rats. Acute food deprivation was unable to change decreased responsiveness to low concentrations but eliminated increased responsiveness to high concentrations in obese SD rats, and leptin administration in weight-reduced SD rats shifted concentration-response curves toward that seen in the obese state in the brief access lick test. "Wanting" and reinforcement learning as assessed in the incentive runway and progressive ratio lever-pressing paradigms was paradoxically decreased in both obese (compared with lean SD rats) and OP (compared with OR rats). Thus, reversible, obesity-associated, reduced "liking" and "wanting" of low-calorie foods in SD rats suggest a role for secondary effects of the obese state on reward functions, while similar differences between select lines of OP and OR rats before induction of obesity indicate a genetic component.
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Affiliation(s)
- Andrew C Shin
- Neurobiology of Nutrition Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana, USA
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Tucci S, Flögel U, Sturm M, Borsch E, Spiekerkoetter U. Disrupted fat distribution and composition due to medium-chain triglycerides in mice with a β-oxidation defect. Am J Clin Nutr 2011; 94:439-49. [PMID: 21697078 DOI: 10.3945/ajcn.111.012948] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Because of the enhanced recognition of inherited long-chain fatty acid oxidation disorders by worldwide newborn screening programs, an increasing number of asymptomatic patients receive medium-chain triglyceride (MCT) supplements to prevent the development of cardiomyopathy and myopathy. OBJECTIVE MCT supplementation has been recognized as a safe dietary intervention, but long-term observations into later adulthood are still not available. We investigated the consequences of a prolonged MCT diet on abdominal fat distribution and composition and on liver fat. DESIGN Mice with very-long-chain acyl-coenzyme A dehydrogenase deficiency (VLCAD(-/-)) were supplemented for 1 y with a diet in which MCTs replaced long-chain triglycerides without increasing the total fat content. The dietary effects on abdominal fat accumulation and composition were analyzed by in vivo (1)H- and (13)C-magnetic resonance spectroscopy (9.4 Tesla). RESULTS After 1 y of MCT supplementation, VLCAD(-/-) mice accumulated massive visceral fat and had a dramatic increase in the concentration of serum free fatty acids. Furthermore, we observed a profound shift in body triglyceride composition, ie, concentrations of physiologically important polyunsaturated fatty acids dramatically decreased. (1)H-Magnetic resonance spectroscopy analysis and histologic evaluation of the liver also showed pronounced fat accumulation and marked oxidative stress. CONCLUSION Although the MCT-supplemented diet has been reported to prevent the development of cardiomyopathy and skeletal myopathy in fatty acid oxidation disorders, our data show that long-term MCT supplementation results in a severe clinical phenotype similar to that of nonalcoholic steatohepatitis and the metabolic syndrome.
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Affiliation(s)
- Sara Tucci
- Department of General Pediatrics, University Children's Hospital, Düsseldorf, Germany.
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Thornton SJ, Wong IT, Neumann R, Kozlowski P, Wasan KM. Dietary supplementation with phytosterol and ascorbic acid reduces body mass accumulation and alters food transit time in a diet-induced obesity mouse model. Lipids Health Dis 2011; 10:107. [PMID: 21711516 PMCID: PMC3141547 DOI: 10.1186/1476-511x-10-107] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 06/28/2011] [Indexed: 01/21/2023] Open
Abstract
Previous research indicates that animals fed a high fat (HF) diet supplemented with disodium ascorbyl phytostanyl phosphate (DAPP) exhibit reduced mass accumulation when compared to HF control. This compound is a water-soluble phytostanol ester and consists of a hydrophobic plant stanol covalently bonded to ascorbic acid (Vitamin C). To provide insight into the mechanism of this response, we examined the in vivo effects of a high fat diet supplemented with ascorbic acid (AA) in the presence and absence of unesterified phytosterols (PS), and set out to establish whether the supplements have a synergistic effect in a diet-induced obesity mouse model. Our data indicate that HF diet supplementation with a combination of 1% w/w phytosterol and 1% w/w ascorbic acid results in reduced mass accumulation, with mean differences in absolute mass between PSAA and HF control of 10.05%; and differences in mass accumulation of 21.6% (i.e. the PSAA group gained on average 21% less mass each week from weeks 7-12 than the HF control group). In our previous study, the absolute mass difference between the 2% DAPP and HF control was 41%, while the mean difference in mass accumulation between the two groups for weeks 7-12 was 67.9%. Mass loss was not observed in animals supplemented with PS or AA alone. These data suggest that the supplements are synergistic with respect to mass accumulation, and the esterification of the compounds further potentiates the response. Our data also indicate that chronic administration of PS, both in the presence and absence of AA, results in changes to fecal output and food transit time, providing insight into the possibility of long-term changes in intestinal function related to PS supplementation.
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Affiliation(s)
- Sheila J Thornton
- Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, BC, Canada.
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Speck M, Cho YM, Asadi A, Rubino F, Kieffer TJ. Duodenal-jejunal bypass protects GK rats from {beta}-cell loss and aggravation of hyperglycemia and increases enteroendocrine cells coexpressing GIP and GLP-1. Am J Physiol Endocrinol Metab 2011; 300:E923-32. [PMID: 21304061 DOI: 10.1152/ajpendo.00422.2010] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Dramatic improvement of type 2 diabetes is commonly observed after bariatric surgery. However, the mechanisms behind the alterations in glucose homeostasis are still elusive. We examined the effect of duodenal-jejunal bypass (DJB), which maintains the gastric volume intact while bypassing the entire duodenum and the proximal jejunum, on glycemic control, β-cell mass, islet morphology, and changes in enteroendocrine cell populations in nonobese diabetic Goto-Kakizaki (GK) rats and nondiabetic control Wistar rats. We performed DJB or sham surgery in GK and Wistar rats. Blood glucose levels and glucose tolerance were monitored, and the plasma insulin, glucagon-like peptide-1 (GLP-1), and glucose-dependent insulinotropic polypeptide (GIP) levels were measured. β-Cell area, islet fibrosis, intestinal morphology, and the density of enteroendocrine cells expressing GLP-1 and/or GIP were quantified. Improved postprandial glycemia was observed from 3 mo after DJB in diabetic GK rats, persisting until 12 mo after surgery. Compared with the sham-GK rats, the DJB-GK rats had an increased β-cell area and a decreased islet fibrosis, increased insulin secretion with increased GLP-1 secretion in response to a mixed meal, and an increased population of cells coexpressing GIP and GLP-1 in the jejunum anastomosed to the stomach. In contrast, DJB impaired glucose tolerance in nondiabetic Wistar rats. In conclusion, although DJB worsens glucose homeostasis in normal nondiabetic Wistar rats, it can prevent long-term aggravation of glucose homeostasis in diabetic GK rats in association with changes in intestinal enteroendocrine cell populations, increased GLP-1 production, and reduced β-cell deterioration.
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Affiliation(s)
- Madeleine Speck
- Dept. of Cellular and Physiological Sciences, Life Sciences Institute, Univ. of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, Canada V6T 1Z3
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Huynh FK, Levi J, Denroche HC, Gray SL, Voshol PJ, Neumann UH, Speck M, Chua SC, Covey SD, Kieffer TJ. Disruption of hepatic leptin signaling protects mice from age- and diet-related glucose intolerance. Diabetes 2010; 59:3032-40. [PMID: 20876720 PMCID: PMC2992763 DOI: 10.2337/db10-0074] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE The liver plays a critical role in integrating and controlling glucose metabolism. Thus, it is important that the liver receive and react to signals from other tissues regarding the nutrient status of the body. Leptin, which is produced and secreted from adipose tissue, is a hormone that relays information regarding the status of adipose depots to other parts of the body. Leptin has a profound influence on glucose metabolism, so we sought to determine if leptin may exert this effect in part through the liver. RESEARCH DESIGN AND METHODS To explore this possibility, we created mice that have disrupted hepatic leptin signaling using a Cre-lox approach and then investigated aspects of glucose metabolism in these animals. RESULTS The loss of hepatic leptin signaling did not alter body weight, body composition, or blood glucose levels in the mild fasting or random-fed state. However, mice with ablated hepatic leptin signaling had increased lipid accumulation in the liver. Further, as male mice aged or were fed a high-fat diet, the loss of hepatic leptin signaling protected the mice from glucose intolerance. Moreover, the mice displayed increased liver insulin sensitivity and a trend toward enhanced glucose-stimulated plasma insulin levels. Consistent with increased insulin sensitivity, mice with ablated hepatic leptin signaling had increased insulin-stimulated phosphorylation of Akt in the liver. CONCLUSIONS These data reveal that unlike a complete deficiency of leptin action, which results in impaired glucose homeostasis, disruption of leptin action in the liver alone increases hepatic insulin sensitivity and protects against age- and diet-related glucose intolerance. Thus, leptin appears to act as a negative regulator of insulin action in the liver.
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Affiliation(s)
- Frank K. Huynh
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jasna Levi
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Heather C. Denroche
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sarah L. Gray
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Peter J. Voshol
- Metabolic Research Laboratories, Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Ursula H. Neumann
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Madeleine Speck
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Streamson C. Chua
- Departments of Medicine and Neuroscience, Albert Einstein College of Medicine, New York, New York
| | - Scott D. Covey
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
- Corresponding authors: Scott D. Covey, , and Timothy J. Kieffer,
| | - Timothy J. Kieffer
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
- Corresponding authors: Scott D. Covey, , and Timothy J. Kieffer,
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Frutos MGS, Pistell PJ, Ingram DK, Berthoud HR. Feed efficiency, food choice, and food reward behaviors in young and old Fischer rats. Neurobiol Aging 2010; 33:206.e41-53. [PMID: 20970890 DOI: 10.1016/j.neurobiolaging.2010.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 08/25/2010] [Accepted: 09/09/2010] [Indexed: 11/25/2022]
Abstract
Increased susceptibility to energy imbalance and anorexia in old age are risk factors for malnutrition during aging, but the underlying mechanisms are not well understood. Here, we explored changes in taste-guided hedonic value ("liking") and motivation to obtain ("wanting") palatable foods as potential mediators of age-associated anorexia and weight loss in old Fischer-344 rats. "Liking" as measured by the number of positive hedonic orofacial responses to sucrose and corn oil was not different in old compared with young rats. Taste-guided, low effort "wanting" as measured by the number of licks per 10 seconds was also not different, although old rats exhibited a slight oromotor impairment as revealed by significantly increased interlick intervals. Medium effort "wanting" as measured by performance in the incentive runway was significantly decreased in old versus young rats. Although decreased net running speed was partially accountable, significantly increased duration of distractions suggested additional deficits in motivation and/or reinforcement learning. Together with early satiation on corn oil but not sucrose in aged rats, these changes are likely to have resulted in the significantly greater sucrose preference of old rats in 12-hour tests, and may ultimately lead to reduced energy intake and weight loss.
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Affiliation(s)
- Miriam García-San Frutos
- Neurobiology of Nutrition Laboratory, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA.
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Lee RS, Tamashiro KLK, Yang X, Purcell RH, Harvey A, Willour VL, Huo Y, Rongione M, Wand GS, Potash JB. Chronic corticosterone exposure increases expression and decreases deoxyribonucleic acid methylation of Fkbp5 in mice. Endocrinology 2010; 151:4332-43. [PMID: 20668026 PMCID: PMC2940504 DOI: 10.1210/en.2010-0225] [Citation(s) in RCA: 198] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
There is evidence for hypercortisolemia playing a role in the generation of psychiatric symptoms and for epigenetic variation within hypothalamic-pituitary-adrenal (HPA) axis genes mediating behavioral changes. We tested the hypothesis that expression changes would be induced in Fkbp5 and other HPA axis genes by chronic exposure to corticosterone and that these changes would occur through the epigenetic mechanism of loss or gain of DNA methylation (DNAm). We administered corticosterone (CORT) to C57BL/6J mice via their drinking water for 4 wk and tested for behavioral and physiological changes and changes in gene expression levels using RNA extracted from hippocampus, hypothalamus, and blood for the following HPA genes: Fkbp5, Nr3c1, Hsp90, Crh, and Crhr1. The CORT mice exhibited anxiety-like behavior in the elevated plus maze test. Chronic exposure to CORT also caused a significant decrease in the hippocampal and blood mRNA levels of Nr3c1 and a decrease in Hsp90 in blood and caused an increase in Fkbp5 for all tissues. Differences were seen in Fkbp5 methylation in hippocampus and hypothalamus. To isolate a single-cell type, we followed up with an HT-22 mouse hippocampal neuronal cell line exposed to CORT. After 7 d, we observed a 2.4-fold increase in Fkbp5 expression and a decrease in DNAm. In the CORT-treated mice, we also observed changes in blood DNAm in Fkbp5. Our results suggest DNAm plays a role in mediating effects of glucocorticoid exposure on Fkbp5 function, with potential consequences for behavior.
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Affiliation(s)
- Richard S Lee
- Department of Psychiatry, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21287-7419, USA
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Abstract
Context Roux-en-Y gastric bypass surgery (RYGB) is currently the most effective treatment for morbid obesity and clinical studies suggest that RYGB patients change food preferences and the desire to eat. Objective To examine hedonic reactions to palatable foods and food choice behavior in an established rat model of Roux-en-Y gastric bypass surgery (RYGB). Methods and Design Male Sprague-Dawley rats and selected line obesity-prone rats that were rendered obese on a high-fat diet underwent RYGB or sham surgery and were tested for ‘liking’ and ‘wanting’ of palatable foods at different caloric densities 4 – 6 months after surgery. Results Compared with sham-operated (obese) and age-matched lean control rats, RYGB rats of both models exhibited more positive orofacial responses to low concentrations of sucrose but fewer to high concentrations. These changes in ‘liking’ by RYGB rats were translated into a shift of the concentration-response curve in the brief access test, with more vigorous licking of low concentrations of sucrose and corn oil, but less licking of the highest concentrations. The changes in hedonic evaluation also resulted in lower long-term preference/acceptance of high-fat diets compared with sham-operated (obese) rats. Furthermore, the reduced ‘wanting’ of a palatable reward in the incentive runway seen in sham-operated obese SD rats was fully restored after RYGB to the level found in lean control rats. Conclusions The results suggest that RYGB leads to a shift in hedonic evaluation, favoring low over high calorie foods and restores obesity-induced alterations in ‘liking’ and ‘wanting’. It remains to be determined whether these effects are simply due to weight loss or specific changes in gut-brain communication. Given the emerging evidence for modulation of cortico-limbic brain structures involved in reward mechanisms by gut hormones, RYGB-induced changes in the secretion of these hormones could potentially be mediating these effects.
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Affiliation(s)
- A C Shin
- Neurobiology of Nutrition Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA, USA
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30
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Nixon JP, Zhang M, Wang C, Kuskowski MA, Novak CM, Levine JA, Billington CJ, Kotz CM. Evaluation of a quantitative magnetic resonance imaging system for whole body composition analysis in rodents. Obesity (Silver Spring) 2010; 18:1652-9. [PMID: 20057373 PMCID: PMC2919581 DOI: 10.1038/oby.2009.471] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We evaluated the EchoMRI-900 combination rat and mouse quantitative magnetic resonance (QMR) body composition method in comparison to traditional whole-body chemical carcass composition analysis (CCA) for measurements of fat and fat-free mass in rodents. Live and postmortem (PM) QMR fat and lean mass measurements were obtained for lean, obese and outbred strains of rats and mice, and compared with measurements obtained using CCA. A second group of rats was measured before and after 18 h food or water deprivation. Significant positive correlations between QMR and CCA fat and lean mass measurements were shown for rats and mice. Although all live QMR fat and lean measurements were more precise than CCA for rats, values obtained for mice significantly differed from CCA for lean mass only. QMR performed PM slightly overestimated fat and lean values relative to live QMR but did not show lower precision than live QMR. Food deprivation reduced values for both fat and lean mass; water deprivation reduced estimates of lean mass only. In summary, all measurements using this QMR system were comparable to those obtained by CCA, but with higher overall precision, similar to previous reports for the murine QMR system. However, PM QMR measurements slightly overestimated live QMR values, and lean and fat mass measurements in this QMR system are influenced by hydration status and animal size, respectively. Despite these caveats, we conclude that the EchoMRI QMR system offers a fast in vivo method of body composition analysis, well correlated to but with greater overall precision than CCA.
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Affiliation(s)
- Joshua P Nixon
- Minnesota Craniofacial Research Training Program, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA.
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Shin AC, Zheng H, Townsend RL, Sigalet DL, Berthoud HR. Meal-induced hormone responses in a rat model of Roux-en-Y gastric bypass surgery. Endocrinology 2010; 151:1588-97. [PMID: 20179262 PMCID: PMC2850245 DOI: 10.1210/en.2009-1332] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Roux-en-Y gastric bypass (RYGB) surgery is the most effective treatment for morbid obesity and remission of associated type 2 diabetes, but the mechanisms involved are poorly understood. The aim of the present study was to develop and validate a rat model for RYGB surgery that allows repeated measurement of meal-induced changes in gut and pancreatic hormones via chronic venous catheters. Male Sprague Dawley rats made obese on a palatable high-fat diet were subjected to RYGB or sham surgery and compared with chow-fed, lean controls. Hormonal responses to a mixed-liquid test meal were examined by frequent blood sampling through chronically implanted jugular catheters in freely behaving rats, 3-4 months after surgery, when RYGB rats had significantly reduced body weight and fat mass compared with sham-operated rats. Hyperleptinemia, basal hyperinsulinemia, and hyperglycemia as well as postprandial glucose intolerance seen in sham-operated, obese rats were completely reversed by RYGB and no longer different from lean controls. Postprandial increases in glucagon-like peptide-1, peptide YY, and amylin as well as suppression of ghrelin levels were all significantly augmented in RYGB rats compared with both sham-operated obese and lean control rats. Thus, our rat model replicates most of the salient hormonal and glycemic changes reported in obese patients after RYGB, with the addition of amylin to the list of potential candidate hormones involved in hypophagia, weight loss, and remission of diabetes. The model will be useful for elucidating the specific peripheral and central mechanisms involved in the suppression of appetite, loss of body weight, and remission of type 2 diabetes.
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Affiliation(s)
- Andrew C Shin
- Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, Louisiana 70808, USA
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Sprecher U, Mohr P, Martin RE, Maerki HP, Sanchez RA, Binggeli A, Künnecke B, Christ AD. Novel, non-peptidic somatostatin receptor subtype 5 antagonists improve glucose tolerance in rodents. ACTA ACUST UNITED AC 2010; 159:19-27. [PMID: 19761802 DOI: 10.1016/j.regpep.2009.09.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 09/01/2009] [Accepted: 09/08/2009] [Indexed: 11/26/2022]
Abstract
BACKGROUND Somatostatin regulates numerous endocrine processes, including glucose homeostasis. The contribution and effects of the 5 somatostatin receptors are still unclear, in part due to the lack of suitable subtype specific receptor antagonists. We explored the effects of two novel, non-peptidic, orally bioavailable somatostatin receptor subtype 5 antagonists named Compound A and Compound B on glycemia in animal models of type 2 diabetes after an initial in vitro characterization. METHODS AND RESULTS Compound A led to a dose-dependent decrease in glucose and insulin excursions during an OGTT in Zucker (fa/fa) rats after single treatment by up to 17% and 49%, respectively. Diet-induced obese mice showed after three weeks treatment with compounds A and B a dose-dependent decrease of the glucose excursion of up to 45% and 37%, respectively. In contrast to the acute effect observed in Zucker rats, Compound A showed a dose-dependent insulin increase by up to 72%, whereas body weight, liver triglycerides, ALT and AST were dose-dependently decreased. CONCLUSIONS SSTR5 antagonists have the potential for short- and long-term improvements of the glucose homeostasis in rodent models of type 2 diabetes. Further work on the mechanism and the relevance for human disease is warranted.
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Affiliation(s)
- Urs Sprecher
- Discovery Research, Chemistry and Non-Clinical Safety, F. Hoffmann-La Roche AG, Grenzacherstrasse 124, CH-4070 Basel, Switzerland
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Zheng H, Shin AC, Lenard NR, Townsend RL, Patterson LM, Sigalet DL, Berthoud HR. Meal patterns, satiety, and food choice in a rat model of Roux-en-Y gastric bypass surgery. Am J Physiol Regul Integr Comp Physiol 2009; 297:R1273-82. [PMID: 19726714 PMCID: PMC2777767 DOI: 10.1152/ajpregu.00343.2009] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Accepted: 08/31/2009] [Indexed: 12/22/2022]
Abstract
Gastric bypass surgery efficiently and lastingly reduces excess body weight and reverses type 2 diabetes in obese patients. Although increased energy expenditure may also play a role, decreased energy intake is thought to be the main reason for weight loss, but the mechanisms involved are poorly understood. Therefore, the aim of this study was to characterize the changes in ingestive behavior in a rat model of Roux-en-Y gastric bypass surgery (RYGB). Obese (24% body fat compared with 18% in chow-fed controls), male Sprague-Dawley rats maintained for 15 wk before and 4 mo after RYGB or sham-surgery on a two-choice low-fat/high-fat diet, were subjected to a series of tests assessing energy intake, meal patterning, and food choice. Although sham-operated rats gained an additional 100 g body wt during the postoperative period, RYGB rats lost approximately 100 g. Intake of a nutritionally complete and palatable liquid diet (Ensure) was significantly reduced by approximately 50% during the first 2 wk after RYGB compared with sham surgery. Decreased intake was the result of greatly reduced meal size with only partial compensation by meal frequency, and a corresponding increase in the satiety ratio. Similar results were obtained with solid food (regular or high-fat chow) 6 wk after surgery. In 12- to 24-h two-choice liquid or solid diet paradigms with nutritionally complete low- and high-fat diets, RYGB rats preferred the low-fat choice (solid) or showed decreased acceptance for the high-fat choice (liquid), whereas sham-operated rats preferred the high-fat choices. A separate group of rats offered chow only before surgery completely avoided the solid high-fat diet in a choice paradigm. The results confirm anecdotal reports of "nibbling" behavior and fat avoidance in RYGB patients and provide a basis for more mechanistic studies in this rat model.
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Affiliation(s)
- Huiyuan Zheng
- Neurobiology of Nutrition Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana70808, USA
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Transplantation of PC1/3-Expressing alpha-cells improves glucose handling and cold tolerance in leptin-resistant mice. Mol Ther 2008; 17:191-8. [PMID: 18941442 DOI: 10.1038/mt.2008.219] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Type 2 diabetes (T2D) is characterized by elevated blood glucose levels owing to insufficient secretion and/or activity of the glucose-lowering hormone insulin. Glucagon-like peptide-1 (GLP-1) has received much attention as a new treatment for diabetes because of its multiple blood glucose-lowering effects, including glucose-dependent enhancement of insulin secretion, inhibition of gastric emptying, and promotion of the survival and growth of insulin-producing beta-cells. GLP-1, along with GLP-2 and oxyntomodulin, is produced in the intestinal L-cell via processing of proglucagon by prohormone convertase 1/3 (PC1/3), while in the pancreatic alpha-cell, coexpression of proglucagon and the alternate enzyme PC2 typically results in differential processing of proglucagon to yield glucagon. We used alginate-encapsulated alpha-cells as a model to evaluate continuous delivery of PC1/3- or PC2-derived proglucagon products. In high fat-fed and db/db mice, PC1/3-, but not PC2-expressing alpha-cells improved glucose handling and transiently lowered fasting glucose levels, suggesting that continuous delivery of PC1/3-derived proglucagon products via cell therapy may be useful for diabetes treatment. In addition, we show that long-term treatment with PC1/3-expressing, but not PC2-expressing, alpha-cells improved cold-induced thermogenesis in db/db mice, demonstrating a previously unappreciated effect of one or more PC1/3-derived alpha-cell products.
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Thornton SJ, Warburton C, Wasan KM, Kozlowski P. Treatment with a Cholesterol Absorption Inhibitor (FM-VP4) Reduces Body Mass and Adipose Accumulation in Developing and Pre-Obese Mice. Drug Dev Ind Pharm 2008; 33:1058-69. [DOI: 10.1080/03639040601133746] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Tantemsapya N, Meinzner-Derr J, Erwin CR, Warner BW. Body composition and metabolic changes associated with massive intestinal resection in mice. J Pediatr Surg 2008; 43:14-9. [PMID: 18206448 DOI: 10.1016/j.jpedsurg.2007.09.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2007] [Accepted: 09/02/2007] [Indexed: 10/22/2022]
Abstract
BACKGROUND The specific changes in body composition and metabolism during the adaptation response to massive intestinal loss are presently unclear. The present study was designed to determine alterations in these parameters using an established mouse model. METHODS Male C57/Bl6 mice underwent either 50% small bowel resection (SBR) or transection with reanastomosis (Sham) operation. Oxygen consumption per unit time, carbon dioxide production per unit time, respiratory quotient, and energy expenditure were measured by indirect calorimetry along with body composition determination by nuclear magnetic resonance at postoperative days 1, 3, 7, 14, 21, and 28. RESULTS The mice that underwent SBR had lower rates of metabolism as measured by decreased energy expenditure, carbon dioxide production per unit time and oxygen consumption per unit time when compared with the Sham group throughout the study period. During adaptation, SBR mice had restoration of body fat at two weeks after the operation while the lean mass and body weight remained lower throughout. CONCLUSION Without supplemental parenteral nutrition, the adaptation response to massive SBR is characterized by reduced energy metabolism and an inappropriate replenishment of fat stores over lean mass. Futures studies will be needed to determine the metabolic effects of various growth factors designed to enhance structural features of adaptation.
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Affiliation(s)
- Niramol Tantemsapya
- Division of Pediatric General and Thoracic Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229-3039, USA
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37
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Schummer CM, Werner U, Tennagels N, Schmoll D, Haschke G, Juretschke HP, Patel MS, Gerl M, Kramer W, Herling AW. Dysregulated pyruvate dehydrogenase complex in Zucker diabetic fatty rats. Am J Physiol Endocrinol Metab 2008; 294:E88-96. [PMID: 17957038 DOI: 10.1152/ajpendo.00178.2007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The mitochondrial pyruvate dehydrogenase complex (PDC) is inactivated in many tissues during starvation and diabetes. We investigated carbohydrate oxidation (CHO) and the regulation of the PDC in lean and obese Zucker diabetic fatty (ZDF) rats during fed and starved conditions as well as during an oral glucose load without and with pharmacologically reduced levels of free fatty acids (FFA) to estimate the relative contribution of FFA on glucose tolerance, CHO, and PDC activity. The increase in total PDC activity (20-45%) was paralleled by increased protein levels ( approximately 2-fold) of PDC subunits in liver and muscle of obese ZDF rats. Pyruvate dehydrogenase kinase-4 (PDK4) protein levels were higher in obese rats, and consequently PDC activity was reduced. Although PDK4 protein levels were rapidly downregulated (57-62%) in both lean and obese animals within 2 h after glucose challenge, CHO over 3 h as well as the peak of PDC activity (1 h after glucose load) in liver and muscle were significantly lower in obese rats compared with lean rats. Similar differences were obtained with pharmacologically suppressed FFA by nicotinic acid, but with significantly improved glucose tolerance in obese rats, as well as increased CHO and delta increases in PDC activity (0-60 min) both in muscle and liver. These results demonstrated the suppressive role of FFA acids on the measured parameters. Furthermore, the results clearly demonstrate a rapid reactivation of PDC in liver and muscle of lean and obese rats after a glucose load and show that PDC activity is significantly lower in obese ZDF rats.
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Affiliation(s)
- Christoph M Schummer
- Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, 65926 Frankfurt am Main, Germany
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London E, Lala G, Berger R, Panzenbeck A, Kohli AA, Renner M, Jackson A, Raynor T, Loya K, Castonguay TW. Sucrose access differentially modifies 11beta-hydroxysteroid dehydrogenase-1 and hexose-6-phosphate dehydrogenase message in liver and adipose tissue in rats. J Nutr 2007; 137:2616-21. [PMID: 18029473 DOI: 10.1093/jn/137.12.2616] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
11Beta-hydroxysteroid dehydrogenase-1 (11beta-HSD-1) plays a key role in the regulation of intracellular glucocorticoid concentrations. Increased message and/or activity of adipose 11beta-HSD-1 are characteristics of human and animal models of obesity. Hexose-6-phosphate dehydrogenase (H6PDH) is colocalized with 11beta-HSD-1 and may be a critical factor in determining the oxo-reductase activity of 11beta-HSD-1. This study examined the effects of sucrose solution access on body weight, body composition, and message of 11beta-HSD-1 and H6PDH in mesenteric adipose and liver. Rats were assigned to 3 groups: 1) control (ad libitum intake of nonpurified diet and water only); 2) ad libitum intake of 16% sucrose solution (S16); or 3) ad libitum intake of 32% sucrose solution (S32) in addition to ad libitum intake of diet and water. The S32 group consumed more energy daily than the S16 and control groups, yet body weight did not differ among groups. Percentages of body fat did not differ between the S16 and S32 groups but were higher than in controls. Hepatic 11beta-HSD-1 message was suppressed by 46% in the S16 group and by 47% in the S32 group, whereas the H6PDH message nearly doubled in the S16 group compared to the control group. In mesenteric fat, 11beta-HSD-1 message increased 23-fold in the S16 group and 32-fold in the S32 group and the H6PDH message increased 3.5-fold in the S16 group compared to the control group. These data demonstrate that sucrose can promote increased 11beta-HSD-1 and H6PDH message in mesenteric fat while concomitantly decreasing 11beta-HSD-1 message and increasing H6PDH message in liver. These observations support the hypothesis that sucrose access causes obesity via its ability to increase adipose 11beta-HSD-1.
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Affiliation(s)
- Edra London
- Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA
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39
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MacDonald MLE, Singaraja RR, Bissada N, Ruddle P, Watts R, Karasinska JM, Gibson WT, Fievet C, Vance JE, Staels B, Hayden MR. Absence of stearoyl-CoA desaturase-1 ameliorates features of the metabolic syndrome in LDLR-deficient mice. J Lipid Res 2007; 49:217-29. [PMID: 17960025 DOI: 10.1194/jlr.m700478-jlr200] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A combination of the interrelated metabolic risk factors obesity, insulin resistance, dyslipidemia, and hypertension, often described as the "metabolic syndrome," is known to increase the risk of developing cardiovascular disease and diabetes. Stearoyl-coenzyme A desaturase (SCD) activity has been implicated in the metabolic syndrome, but detailed studies of the beneficial metabolic effects of SCD deficiency have been limited. Here, we show that absence of the Scd1 gene product reduces plasma triglycerides and reduces weight gain in severely hyperlipidemic low density lipoprotein receptor (LDLR)-deficient mice challenged with a Western diet. Absence of SCD1 also increases insulin sensitivity, as measured by intraperitoneal glucose and insulin tolerance testing. SCD1 deficiency dramatically reduces hepatic lipid accumulation while causing more modest reductions in plasma apolipoproteins, suggesting that in conditions of sustained hyperlipidemia, SCD1 functions primarily to mediate lipid stores. In addition, absence of SCD1 partially ameliorates the undesirable hypertriglyceridemic effect of antiatherogenic liver X receptor agonists. Our results demonstrate that constitutive reduction of SCD activity improves the metabolic phenotype of LDLR-deficient mice on a Western diet.
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Affiliation(s)
- Marcia L E MacDonald
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
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40
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Tamashiro KLK, Nguyen MMN, Ostrander MM, Gardner SR, Ma LY, Woods SC, Sakai RR. Social stress and recovery: implications for body weight and body composition. Am J Physiol Regul Integr Comp Physiol 2007; 293:R1864-74. [PMID: 17855491 DOI: 10.1152/ajpregu.00371.2007] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Social stress resulting from dominant-subordinate relationships is associated with body weight loss and altered body composition in subordinate (SUB) male rats. Here, we extend these findings to determine whether stress-induced changes in energy homeostasis persist when the social stress is removed, and the animal is allowed to recover. We examined body weight (BW), body composition, and relevant endocrine measures after one or two cycles of 14 days of social stress, each followed by 21 days of recovery in each rat's individual home cage. SUB lost significantly more BW during social housing in a visible burrow system (VBS) compared with dominant (DOM) animals. Weight loss during social stress was attributable to a decrease in adipose tissue in DOM and SUB, with an additional loss of lean tissue in SUB. During both 21-day recovery periods, DOM and SUB regained lost BW, but only SUB were hyperphagic. Following recovery, SUB had a relatively larger increase in adipose tissue and plasma leptin compared with DOM, indicating that body composition changes were dependent on social status. Control animals that were weight matched to SUB or male rats exposed to the VBS environment without females, and that did not form a social hierarchy, did not exhibit changes in body composition like SUB in the VBS. Therefore, chronic social stress causes social status-dependent changes in BW, composition and endocrine measures that persist after repeated stress and recovery cycles and that may ultimately lead to metabolic disorders and obesity.
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Affiliation(s)
- Kellie L K Tamashiro
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH 45237, USA
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41
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Beckmann N, Kneuer R, Gremlich HU, Karmouty-Quintana H, Blé FX, Müller M. In vivo mouse imaging and spectroscopy in drug discovery. NMR IN BIOMEDICINE 2007; 20:154-85. [PMID: 17451175 DOI: 10.1002/nbm.1153] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Imaging modalities such as micro-computed tomography (micro-CT), micro-positron emission tomography (micro-PET), high-resolution MRI, optical imaging, and high-resolution ultrasound have become invaluable tools in preclinical pharmaceutical research. They can be used to non-invasively investigate, in vivo, rodent biology and metabolism, disease models, and pharmacokinetics and pharmacodynamics of drugs. The advantages and limitations of each approach usually determine its application, and therefore a small-rodent imaging laboratory in a pharmaceutical environment should ideally provide access to several techniques. In this paper we aim to illustrate how these techniques may be used to obtain meaningful information for the phenotyping of transgenic mice and for the analysis of compounds in murine models of disease.
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Affiliation(s)
- Nicolau Beckmann
- Discovery Technologies, Novartis Institutes for BioMedical Research, Lichtstrasse 35, CH-4002 Basel, Switzerland.
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42
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Harrington WW, S. Britt C, G. Wilson J, O. Milliken N, G. Binz J, C. Lobe D, R. Oliver W, C. Lewis M, M. Ignar D. The Effect of PPARalpha, PPARdelta, PPARgamma, and PPARpan Agonists on Body Weight, Body Mass, and Serum Lipid Profiles in Diet-Induced Obese AKR/J Mice. PPAR Res 2007; 2007:97125. [PMID: 17710237 PMCID: PMC1940322 DOI: 10.1155/2007/97125] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2006] [Revised: 02/08/2007] [Accepted: 03/03/2007] [Indexed: 12/19/2022] Open
Abstract
Activation of peroxisome proliferator-activated receptor (PPAR) alpha, delta, and gamma subtypes increases expression of genes involved in fatty acid transport and oxidation and alters adiposity in animal models of obesity and type-2 diabetes. PPARpan agonists which activate all three receptor subtypes have antidiabetic activity in animal models without the weight gain associated with selective PPARgamma agonists. Herein we report the effects of selective PPAR agonists (GW9578, a PPARalpha agonist, GW0742, a PPARdelta agonist, GW7845, a PPARgamma agonist), combination of PPARalpha and delta agonists, and PPARpan (PPARalpha/gamma/delta) activators (GW4148 or GW9135) on body weight (BW), body composition, food consumption, fatty acid oxidation, and serum chemistry of diet-induced obese AKR/J mice. PPARalpha or PPARdelta agonist treatment induced a slight decrease in fat mass (FM) while a PPARgamma agonist increased BW and FM commensurate with increased food consumption. The reduction in BW and food intake after cotreatment with PPARalpha and delta agonists appeared to be synergistic. GW4148, a PPARpan agonist, induced a significant and sustained reduction in BW and FM similar to an efficacious dose of rimonabant, an antiobesity compound. GW9135, a PPARpan agonist with weak activity at PPARdelta, induced weight loss initially followed by rebound weight gain reaching vehicle control levels by the end of the experiment. We conclude that PPARalpha and PPARdelta activations are critical to effective weight loss induction. These results suggest that the PPARpan compounds may be expected to maintain the beneficial insulin sensitization effects of a PPARgamma agonist while either maintaining weight or producing weight loss.
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Affiliation(s)
- W. Wallace Harrington
- Department of Metabolic Diseases, GlaxoSmithKline Research, Research Triangle Park, NC 27709, USA
| | - Christy S. Britt
- Department of Metabolic Diseases, GlaxoSmithKline Research, Research Triangle Park, NC 27709, USA
| | - Joan G. Wilson
- Department of Metabolic Diseases, GlaxoSmithKline Research, Research Triangle Park, NC 27709, USA
| | - Naphtali O. Milliken
- Department of Metabolic Diseases, GlaxoSmithKline Research, Research Triangle Park, NC 27709, USA
| | - Jane G. Binz
- Department of Metabolic Diseases, GlaxoSmithKline Research, Research Triangle Park, NC 27709, USA
| | - David C. Lobe
- Department of Metabolic Diseases, GlaxoSmithKline Research, Research Triangle Park, NC 27709, USA
| | - William R. Oliver
- Department of Metabolic Diseases, GlaxoSmithKline Research, Research Triangle Park, NC 27709, USA
| | - Michael C. Lewis
- Department of Metabolic Diseases, GlaxoSmithKline Research, Research Triangle Park, NC 27709, USA
| | - Diane M. Ignar
- Department of Metabolic Diseases, GlaxoSmithKline Research, Research Triangle Park, NC 27709, USA
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Covey SD, Wideman RD, McDonald C, Unniappan S, Huynh F, Asadi A, Speck M, Webber T, Chua SC, Kieffer TJ. The pancreatic beta cell is a key site for mediating the effects of leptin on glucose homeostasis. Cell Metab 2006; 4:291-302. [PMID: 17011502 DOI: 10.1016/j.cmet.2006.09.005] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Revised: 05/08/2006] [Accepted: 09/08/2006] [Indexed: 02/07/2023]
Abstract
The hormone leptin plays a crucial role in maintenance of body weight and glucose homeostasis. This occurs through central and peripheral pathways, including regulation of insulin secretion by pancreatic beta cells. To study this further in mice, we disrupted the signaling domain of the leptin receptor gene in beta cells and hypothalamus. These mice develop obesity, fasting hyperinsulinemia, impaired glucose-stimulated insulin release, and glucose intolerance, similar to leptin receptor null mice. However, whereas complete loss of leptin function causes increased food intake, this tissue-specific attenuation of leptin signaling does not alter food intake or satiety responses to leptin. Moreover, unlike other obese models, these mice have reduced fasting blood glucose. These results indicate that leptin regulation of glucose homeostasis extends beyond insulin sensitivity to influence beta cell function, independent of pathways controlling food intake. These data suggest that defects in this adipoinsular axis could contribute to diabetes associated with obesity.
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Affiliation(s)
- Scott D Covey
- Laboratory of Molecular and Cellular Medicine, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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44
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Nicholson JR, Kohler G, Schaerer F, Senn C, Weyermann P, Hofbauer KG. Peripheral administration of a melanocortin 4-receptor inverse agonist prevents loss of lean body mass in tumor-bearing mice. J Pharmacol Exp Ther 2006; 317:771-7. [PMID: 16436498 DOI: 10.1124/jpet.105.097725] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cachexia affects many different chronically ill patient populations, including those with cancer. It results in loss of body weight, particularly of lean body mass (LBM), and is estimated to be responsible for over 20% of all cancer-related deaths. Currently, available drugs are ineffective, and new therapies are urgently needed. Melanocortin 4-receptor (MC4-R) blockade has been shown recently to be effective in preventing cancer cachexia in rodent models. In the present study, we have tested a MC4-R blocker, ML00253764 [2-{2-[2-(5-bromo-2-methoxyphenyl)-ethyl]-3-fluorophenyl}-4,5-dihydro-1H-imidazolium hydrochloride] (Vos et al., 2004), in vitro and in vivo. In membranes of human embryonic kidney 293 cells expressing human MC4-R, ML00253764 displaced [Nle(4), d-Phe(7)]-alpha-melanocyte-stimulating hormone binding with an IC(50) of 0.32 microM. At concentrations above 1 microM, ML00253764 decreased cAMP accumulation (maximal reduction of -20%) indicative of inverse agonist activity. ML00253764 was administered twice daily (15 mg/kg s.c.) for 13 days to C57BL6 mice bearing s.c. Lewis lung carcinoma tumors. Food intake and body weight were measured, and body composition was assessed using magnetic resonance relaxometry. ML00253764 stimulated light-phase food intake relative to vehicle-treated controls (p < 0.05), although no effect was observed on 24-h food intake. During the 21 days of the experiment, the LBM of tumor vehicle-treated mice decreased (p < 0.05). In contrast, the tumor-bearing mice treated with ML00253764 maintained their LBM. These data support the view that MC4-R blockade may be a suitable approach for the treatment of cancer cachexia and that MC4-R inverse agonists may have potential as drug candidates.
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Affiliation(s)
- Janet R Nicholson
- Applied Pharmacology, Biozentrum, University of Basel, Klingelbergstrasse 50, CH-4056 Basel, Switzerland
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