1
|
Okikawa S, Kashihara H, Shimada M, Yoshikawa K, Tokunaga T, Nishi M, Takasu C, Wada Y, Yoshimoto T. Effect of duodenal-jejunal bypass on diabetes in the early postoperative period. Sci Rep 2023; 13:1856. [PMID: 36726038 PMCID: PMC9892584 DOI: 10.1038/s41598-023-28923-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Accepted: 01/27/2023] [Indexed: 02/03/2023] Open
Abstract
Metabolic surgery is an effective treatment for patients with type 2 diabetes mellitus (T2DM). The aim of this study was to investigate the effect of duodenal-jejunal bypass (DJB) in a rat model of T2DM during the early postoperative period. A rat model of non-obese T2DM was allocated to two groups: a sham group and a DJB group. On postoperative day 1 (1POD), oral glucose tolerance testing (OGTT) was performed and the changes of glucose transporter expressions in the small intestine was evaluated. [18F]-fluorodeoxyglucose ([18]-FDG) uptake was measured in sham- and DJB-operated rats using positron emission tomography-computed tomography (PET-CT). DJB improved the glucose tolerance of the rats on 1POD. The expression of sodium-glucose cotransporter 1 (SGLT1) and glucose transporter 1 (GLUT1) was high, and that of GLUT2 was low in the alimentary limb (AL) of rats in the DJB group. PET-CT showed that [18F]-FDG uptake was high in the proximal jejunum of DJB-operated rats. These results may show that DJB improve glucose tolerance in very early postoperative period as the result of glucose accumulation in the AL because of changes in glucose transporter expression.
Collapse
Affiliation(s)
- Shohei Okikawa
- Department of Surgery, Tokushima University, 3-18-15 Kuramoto-Cho, Tokushima, Tokushima, 770-8503, Japan
| | - Hideya Kashihara
- Department of Surgery, Tokushima University, 3-18-15 Kuramoto-Cho, Tokushima, Tokushima, 770-8503, Japan.
| | - Mitsuo Shimada
- Department of Surgery, Tokushima University, 3-18-15 Kuramoto-Cho, Tokushima, Tokushima, 770-8503, Japan
| | - Kozo Yoshikawa
- Department of Surgery, Tokushima University, 3-18-15 Kuramoto-Cho, Tokushima, Tokushima, 770-8503, Japan
| | - Takuya Tokunaga
- Department of Surgery, Tokushima University, 3-18-15 Kuramoto-Cho, Tokushima, Tokushima, 770-8503, Japan
| | - Masaaki Nishi
- Department of Surgery, Tokushima University, 3-18-15 Kuramoto-Cho, Tokushima, Tokushima, 770-8503, Japan
| | - Chie Takasu
- Department of Surgery, Tokushima University, 3-18-15 Kuramoto-Cho, Tokushima, Tokushima, 770-8503, Japan
| | - Yuma Wada
- Department of Surgery, Tokushima University, 3-18-15 Kuramoto-Cho, Tokushima, Tokushima, 770-8503, Japan
| | - Toshiaki Yoshimoto
- Department of Surgery, Tokushima University, 3-18-15 Kuramoto-Cho, Tokushima, Tokushima, 770-8503, Japan
| |
Collapse
|
2
|
Joly-Amado A, Soty M, Philippe E, Lacombe A, Castel J, Pillot B, Vily-Petit J, Zitoun C, Mithieux G, Magnan C. Portal Glucose Infusion, Afferent Nerve Fibers, and Glucose and Insulin Tolerance of Insulin-Resistant Rats. J Nutr 2022; 152:1862-1871. [PMID: 35511216 DOI: 10.1093/jn/nxac097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 01/19/2022] [Accepted: 04/26/2022] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The role of hepatoportal glucose sensors is poorly understood in the context of insulin resistance. OBJECTIVES We assessed the effects of glucose infusion in the portal vein on insulin tolerance in 2 rat models of insulin resistance, and the role of capsaicin sensitive nerves in this signal. METHODS Male Wistar rats, 8 weeks old, weighing 250-275 g, were used. Insulin and glucose tolerance were assessed following a 4-hour infusion of either glucose or saline through catheterization in the portal vein in 3 paradigms. In experiment 1, for diet-induced insulin resistance, rats were fed either a control diet (energy content: proteins = 22.5%, carbohydrates = 64.1%, and lipids = 13.4%) or a high-fat diet (energy content: proteins = 15.3%, carbohydrates = 40.3%, and lipids =44.4%) for 4 months. In experiment 2, for centrally induced peripheral insulin resistance, catheters were inserted in the carotid artery to deliver either an emulsion of triglycerides [intralipid (IL)] or saline towards the brain for 24 hours. In experiment 3, for testing the role of capsaicin-sensitive nerves, experiment 2 was repeated following a periportal treatment with capsaicin or vehicle. RESULTS In experiment 1, when compared to rats fed the control diet, rats fed the high-fat diet exhibited decreased insulin and glucose tolerance (P ≤ 0.05) that was restored with a glucose infusion in the portal vein (P ≤ 0.05). In experiment 2, infusion of a triglyceride emulsion towards the brain (IL rats) decreased insulin and glucose tolerance and increased hepatic endogenous production when compared to saline-infused rats (P ≤ 0.05). Glucose infusion in the portal vein in IL rats restored insulin and glucose tolerance, as well as hepatic glucose production, to controls levels (P ≤ 0.05). In experiment 3, portal infusion of glucose did not increase insulin tolerance in IL rats that received a periportal pretreatment with capsaicin. CONCLUSIONS Stimulation of hepatoportal glucose sensors increases insulin tolerance in rat models of insulin resistance and requires the presence of capsaicin-sensitive nerves.
Collapse
Affiliation(s)
- Aurélie Joly-Amado
- Université de Paris, Functional and Adaptive Biology Unit, UMR (Unite Mixte de Recherche) 8251, CNRS (Centre National de la Recherche Scientifique), Paris, France
| | - Maud Soty
- Institut National de la Santé et de la Recherche Médicale, Lyon, France.,Université de Lyon, Lyon, France.,Université Lyon I, Villeurbanne, France
| | - Erwann Philippe
- Université de Paris, Functional and Adaptive Biology Unit, UMR (Unite Mixte de Recherche) 8251, CNRS (Centre National de la Recherche Scientifique), Paris, France
| | - Amelie Lacombe
- Université de Paris, Functional and Adaptive Biology Unit, UMR (Unite Mixte de Recherche) 8251, CNRS (Centre National de la Recherche Scientifique), Paris, France
| | - Julien Castel
- Université de Paris, Functional and Adaptive Biology Unit, UMR (Unite Mixte de Recherche) 8251, CNRS (Centre National de la Recherche Scientifique), Paris, France
| | - Bruno Pillot
- Institut National de la Santé et de la Recherche Médicale, Lyon, France.,Université de Lyon, Lyon, France.,Université Lyon I, Villeurbanne, France
| | - Justine Vily-Petit
- Institut National de la Santé et de la Recherche Médicale, Lyon, France.,Université de Lyon, Lyon, France.,Université Lyon I, Villeurbanne, France
| | - Carine Zitoun
- Institut National de la Santé et de la Recherche Médicale, Lyon, France.,Université de Lyon, Lyon, France.,Université Lyon I, Villeurbanne, France
| | - Gilles Mithieux
- Institut National de la Santé et de la Recherche Médicale, Lyon, France.,Université de Lyon, Lyon, France.,Université Lyon I, Villeurbanne, France
| | - Christophe Magnan
- Université de Paris, Functional and Adaptive Biology Unit, UMR (Unite Mixte de Recherche) 8251, CNRS (Centre National de la Recherche Scientifique), Paris, France
| |
Collapse
|
3
|
Pruekprasert N, Meng Q, Gu R, Xie H, Liu Y, Liu C, Cooney RN. α7 Nicotinic Acetylcholine Receptor Agonists Regulate Inflammation and Growth Hormone Resistance in Sepsis. Shock 2021; 56:1057-1065. [PMID: 33882516 DOI: 10.1097/shk.0000000000001792] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
ABSTRACT During sepsis the normal induction of circulating insulin-like growth factor-I (IGF-I) by growth hormone (GH) action on liver is attenuated, a phenomenon called hepatic GH resistance. Hepatic GH resistance can be caused by cytokine-mediated activation of the NF-κB pathway which interferes with normal GH-signaling. The afferent and efferent fibers of the vagus nerve are integral to the cholinergic anti-inflammatory pathway (CAP) which attenuates hepatic TNFα production by activating the α7 nicotinic acetylcholine receptor (α7nAChR). We examined the effects of selective afferent vagotomy (SAV) and α7nAChR activation on sepsis-induced mortality, hepatic and systemic inflammation, the GH/IGF system and hepatic GH resistance using Sprague Dawley (SD) rats, C57BL/6 wild type (WT) mice, and α7nAChR knockout (KO) mice. Capsaicin was used to perform SAV and GTS-21 (α7nAChR agonist) was used to activate the α7nAChR. Sepsis-induced mortality, hepatic NF-κB activation, and plasma cytokine levels were increased in SAV rats and reduced in GTS-21-treated mice. The effects of sepsis on the GH/IGF-I system plasma IGF-I, IGF binding protein-1 (IGFBP-1), hepatic IGF-I, IGFBP-1, and GH receptor (GHR) mRNA and rhGH-responsiveness in mice were improved by GTS-21. Collectively these results confirm the protective effects of the anti-inflammatory CAP and α7nAChR activation in sepsis. They also provide evidence the CAP and α7nAChR activation could be used to attenuate hepatic GH resistance and anabolic failure in sepsis.
Collapse
Affiliation(s)
- Napat Pruekprasert
- Departments of Surgery, State University of New York, Upstate Medical University, Syracuse, New York
| | | | | | | | | | | | | |
Collapse
|
4
|
Huang KP, Goodson ML, Vang W, Li H, Page AJ, Raybould HE. Leptin signaling in vagal afferent neurons supports the absorption and storage of nutrients from high-fat diet. Int J Obes (Lond) 2020; 45:348-357. [PMID: 32917985 PMCID: PMC7854885 DOI: 10.1038/s41366-020-00678-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/30/2020] [Accepted: 09/03/2020] [Indexed: 12/18/2022]
Abstract
Objective: Activation of vagal afferent neurons (VAN) by postprandial gastrointestinal signals terminates feeding and facilitates nutrient digestion and absorption. Leptin modulates responsiveness of VAN to meal-related gastrointestinal signals. Rodents with high-fat diet (HF) feeding develop leptin resistance that impairs responsiveness of VAN. We hypothesized that lack of leptin signaling in VAN reduces responses to meal-related signals, which in turn decreases absorption of nutrients and energy storage from high-fat, calorically dense food. Methods: Mice with conditional deletion of the leptin receptor from VAN (Nav1.8-Cre/LepRfl/fl; KO) were used in this study. Six-week-old male mice were fed a 45% HF for 4 weeks; metabolic phenotype, food intake, and energy expenditure were measured. Absorption and storage of nutrients were investigated in the refed state. Results: After 4 weeks of HF feeding, KO mice gained less body weight and fat mass that WT controls, but this was not due to differences in food intake or energy expenditure. KO mice had reduced expression of carbohydrate transporters and absorption of carbohydrate in the jejunum. KO mice had fewer hepatic lipid droplets and decreased expression of de novo lipogenesis-associated enzymes and lipoproteins for endogenous lipoprotein pathway in liver, suggesting decreased long-term storage of carbohydrate in KO mice. Conclusions: Impairment of leptin signaling in VAN reduces responsiveness to gastrointestinal signals, which reduces intestinal absorption of carbohydrates and de novo lipogenesis resulting in reduced long-term energy storage. This study reveals a novel role of vagal afferents to support digestion and energy storage that may contribute to the effectiveness of vagal blockade to induce weight loss.
Collapse
Affiliation(s)
- Kuei-Pin Huang
- School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Michael L Goodson
- School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Wendie Vang
- School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Hui Li
- Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia.,South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Amanda J Page
- Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia.,South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Helen E Raybould
- School of Veterinary Medicine, University of California Davis, Davis, CA, USA.
| |
Collapse
|
5
|
Espinoza L, Boychuk CR. Diabetes, and its treatment, as an effector of autonomic nervous system circuits and its functions. Curr Opin Pharmacol 2020; 54:18-26. [PMID: 32721846 DOI: 10.1016/j.coph.2020.06.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 06/18/2020] [Accepted: 06/22/2020] [Indexed: 12/24/2022]
Abstract
Diabetes increases the risk of cardiovascular complications, including heart failure, hypertension, and stroke. There is a strong involvement of autonomic dysfunction in individuals with diabetes that exhibit clinical manifestations of cardiovascular diseases (CVD). Still, the mechanisms by which diabetes and its treatments alter autonomic function and subsequently affect cardiovascular complications remain elusive. For this reason, understanding the brainstem circuits involved in sensing metabolic state(s) and enacting autonomic control of the cardiovascular system are important to develop more comprehensive therapies for individuals with diabetes at increased risk for CVD. We review how autonomic nervous system circuits change during these disease states and discuss their potential role in current pharmacotherapies that target diabetic states. Overall, this review proposes that the brainstem circuits provide an integrative sensorimotor network capable of responding to metabolic cues to regulate cardiovascular function and this network is modified by, and in turn affects, diabetes-induced CVD and its treatment.
Collapse
Affiliation(s)
- Liliana Espinoza
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, United States
| | - Carie R Boychuk
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, United States.
| |
Collapse
|
6
|
Moran A, Al-Rammahi MA, Daly K, Grand E, Ionescu C, Bravo DM, Wall EH, Shirazi-Beechey SP. Consumption of a Natural High-Intensity Sweetener Enhances Activity and Expression of Rabbit Intestinal Na +/Glucose Cotransporter 1 (SGLT1) and Improves Colibacillosis-Induced Enteric Disorders. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:441-450. [PMID: 31736308 PMCID: PMC7007240 DOI: 10.1021/acs.jafc.9b04995] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 11/14/2019] [Accepted: 11/16/2019] [Indexed: 06/10/2023]
Abstract
Absorption of glucose, via intestinal Na+/glucose cotransporter 1 (SGLT1), activates salt and water absorption and is an effective route for treating Escherichia coli (E. coli)-induced diarrhea. Activity and expression of SGLT1 is regulated by sensing of sugars and artificial/natural sweeteners by the intestinal sweet receptor T1R2-T1R3 expressed in enteroendocrine cells. Diarrhea, caused by the bacterial pathogen E. coli, is the most common post-weaning clinical feature in rabbits, leading to mortality. We demonstrate here that, in rabbits with experimentally E. coli-induced diarrhea, inclusion of a supplement containing stevia leaf extract (SL) in the feed decreases cumulative morbidity, improving clinical signs of disease (p < 0.01). We show that the rabbit intestine expresses T1R2-T1R3. Furthermore, intake of SL enhances activity and expression of SGLT1 and the intestinal capacity to absorb glucose (1.8-fold increase, p < 0.05). Thus, a natural plant extract sweetener can act as an effective feed additive for lessening the negative impact of enteric diseases in animals.
Collapse
Affiliation(s)
- Andrew
W. Moran
- Epithelial
Function and Development Group, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, U.K.
| | - Miran A. Al-Rammahi
- Epithelial
Function and Development Group, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, U.K.
- Zoonotic
Disease Research Unit, College of Veterinary Medicine, University of Al-Qadisiyah, Al-Diwaniyah 58002, Iraq
| | - Kristian Daly
- Epithelial
Function and Development Group, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, U.K.
| | | | | | | | - Emma H. Wall
- Pancosma/ADM, Z. A. La Pièce 3, 1180 Rolle, Switzerland
| | - Soraya P. Shirazi-Beechey
- Epithelial
Function and Development Group, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, U.K.
| |
Collapse
|
7
|
Pal A, Rhoads DB, Tavakkoli A. Effect of Portal Glucose Sensing on Systemic Glucose Levels in SD and ZDF Rats. PLoS One 2016; 11:e0165592. [PMID: 27806092 PMCID: PMC5091783 DOI: 10.1371/journal.pone.0165592] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 10/16/2016] [Indexed: 11/18/2022] Open
Abstract
Background The global epidemic of Type-2-Diabetes (T2D) highlights the need for novel therapeutic targets and agents. Roux-en-Y-Gastric-Bypass (RYGB) is the most effective treatment. Studies investigating the mechanisms of RYGB suggest a role for post-operative changes in portal glucose levels. We investigate the impact of stimulating portal glucose sensors on systemic glucose levels in health and T2D, and evaluated the role of sodium-glucose-cotransporter-3 (SGLT3) as the possible sensor. Methods Systemic glucose and hormone responses to portal stimulation were measured. In Sprague-Dawley (SD) rats, post-prandial state was simulated by infusing glucose into the portal vein. The SGLT3 agonist, alpha-methyl-glucopyranoside (αMG), was then added to further stimulate the portal sensor. To elucidate the neural pathway, vagotomy or portal denervation was followed by αMG+glucose co-infusion. The therapeutic potential of portal glucose sensor stimulation was investigated by αMG-only infusion (vs. saline) in SD and Zucker-Diabetic-Fatty (ZDF) rats. Hepatic mRNA expression was also measured. Results αMG+glucose co-infusion reduced peak systemic glucose (vs. glucose alone), and lowered hepatic G6Pase expression. Portal denervation, but not vagotomy, abolished this effect. αMG-only infusion lowered systemic glucose levels. This glucose-lowering effect was more pronounced in ZDF rats, where portal αMG infusion increased insulin, C-peptide and GIP levels compared to saline infusions. Conclusions The portal vein is capable of sensing its glucose levels, and responds by altering hepatic glucose handling. The enhanced effect in T2D, mediated through increased GIP and insulin, highlights a therapeutic target that could be amenable to pharmacological modulation or minimally-invasive surgery.
Collapse
Affiliation(s)
- Atanu Pal
- Department of Surgery, Brigham and Women’s Hospital, 75 Francis Street, Boston, MA, 02115, United States of America
- Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, United States of America
| | - David B. Rhoads
- Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, United States of America
- Pediatric Endocrine Unit, MassGeneral Hospital for Children, 55 Fruit Street, Boston, MA, 02114, United States of America
| | - Ali Tavakkoli
- Department of Surgery, Brigham and Women’s Hospital, 75 Francis Street, Boston, MA, 02115, United States of America
- Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, United States of America
- Center for Weight Management and Metabolic Surgery, Brigham and Women’s Hospital, 75 Francis Street, Boston, MA, 02115, United States of America
- * E-mail:
| |
Collapse
|
8
|
Lehmann A, Hornby PJ. Intestinal SGLT1 in metabolic health and disease. Am J Physiol Gastrointest Liver Physiol 2016; 310:G887-98. [PMID: 27012770 DOI: 10.1152/ajpgi.00068.2016] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 03/21/2016] [Indexed: 01/31/2023]
Abstract
The Na(+)-glucose cotransporter 1 (SGLT1/SLC5A1) is predominantly expressed in the small intestine. It transports glucose and galactose across the apical membrane in a process driven by a Na(+) gradient created by Na(+)-K(+)-ATPase. SGLT2 is the major form found in the kidney, and SGLT2-selective inhibitors are a new class of treatment for type 2 diabetes mellitus (T2DM). Recent data from patients treated with dual SGLT1/2 inhibitors or SGLT2-selective drugs such as canagliflozin (SGLT1 IC50 = 663 nM) warrant evaluation of SGLT1 inhibition for T2DM. SGLT1 activity is highly dynamic, with modulation by multiple mechanisms to ensure maximal uptake of carbohydrates (CHOs). Intestinal SGLT1 inhibition lowers and delays the glucose excursion following CHO ingestion and augments glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) secretion. The latter is likely due to increased glucose exposure of the colonic microbiota and formation of metabolites such as L cell secretagogues. GLP-1 and PYY secretion suppresses food intake, enhances the ileal brake, and has an incretin effect. An increase in colonic microbial production of propionate could contribute to intestinal gluconeogenesis and mediate positive metabolic effects. On the other hand, a threshold of SGLT1 inhibition that could lead to gastrointestinal intolerability is unclear. Altered Na(+) homeostasis and increased colonic CHO may result in diarrhea and adverse gastrointestinal effects. This review considers the potential mechanisms contributing to positive metabolic and negative intestinal effects. Compounds that inhibit SGLT1 must balance the modulation of these mechanisms to achieve therapeutic efficacy for metabolic diseases.
Collapse
Affiliation(s)
- Anders Lehmann
- Division of Endocrinology, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden; and
| | - Pamela J Hornby
- Cardiovascular and Metabolic Disease, Janssen Research and Development, LLC, Spring House, Pennsylvania
| |
Collapse
|
9
|
Pácha J, Sumová A. Circadian regulation of epithelial functions in the intestine. Acta Physiol (Oxf) 2013; 208:11-24. [PMID: 23461998 DOI: 10.1111/apha.12090] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 02/21/2013] [Accepted: 02/21/2013] [Indexed: 12/24/2022]
Abstract
Many physiological functions exhibit a diurnal rhythmicity that is influenced by biological clocks and feeding rhythms. In this review, we discuss the growing evidence showing the important role of circadian rhythms in regulating intestinal mucosa. First, we introduce the molecular timing system and the interrelationship between the master biological clock in the suprachiasmatic nuclei of the brain and the peripheral intestinal clock and provide evidence that the intestinal clock is entrained with the external environment. Second, we review the circadian rhythmicity of enterocyte proliferation and the largely unknown regulatory mechanisms behind these rhythms. Finally, we focus on the circadian clock control of food processing that functions by regulating the expression of digestive enzymes and intestinal nutrient and salt transporters. The concepts to be discussed highlight the ability of the intestinal epithelium to utilize self-sustained clock signals together with signals associated with changes in the cellular environment and to use endogenous temporal control of the gastrointestinal functions to meet varying physiological and pathophysiological demands. The fact that internal de-synchronizations within the body, such as those that occur in shift workers or with changes in food intake behaviour, are often associated with malfunctions of the gastrointestinal tract indicates that more information about the connections between the circadian clock and intestinal mucosa/transporting enterocytes could provide clues for future therapies.
Collapse
Affiliation(s)
- J. Pácha
- Institute of Physiology; Academy of Sciences of the Czech Republic; Prague; Czech Republic
| | - A. Sumová
- Institute of Physiology; Academy of Sciences of the Czech Republic; Prague; Czech Republic
| |
Collapse
|
10
|
Lin YJ, Lin YS, Lai CJ, Yuan ZF, Ruan T, Kou YR. Perivagal antagonist treatment in rats selectively blocks the reflex and afferent responses of vagal lung C fibers to intravenous agonists. J Appl Physiol (1985) 2012; 114:361-70. [PMID: 23221955 DOI: 10.1152/japplphysiol.00977.2012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The terminals of vagal lung C fibers (VLCFs) express various types of pharmacological receptors that are important to the elicitation of airway reflexes and the development of airway hypersensitivity. We investigated the blockade of the reflex and afferent responses of VLCFs to intravenous injections of agonists using perivagal treatment with antagonists (PAT) targeting the transient receptor potential vanilloid 1, P2X, and 5-HT(3) receptors in anesthetized rats. Blockading these responses via perivagal capsaicin treatment (PCT), which blocks the neural conduction of C fibers, was also studied. We used capsaicin, α,β-methylene-ATP, and phenylbiguanide as the agonists, and capsazepine, iso-pyridoxalphosphate-6-azophenyl-2',5'-disulfonate, and tropisetron as the antagonists of transient receptor potential vanilloid 1, P2X, and 5-HT(3) receptors, respectively. We found that each of the PATs abolished the VLCF-mediated reflex apnea evoked by the corresponding agonist, while having no effect on the response to other agonists. Perivagal vehicle treatment failed to produce any such blockade. These blockades had partially recovered at 3 h after removal of the PATs. In contrast, PCT abolished the reflex apneic response to all three agonists. Both PATs and PCT did not affect the myelinated afferent-mediated apneic response to lung inflation. Consistently, our electrophysiological studies revealed that each of the PATs prevented the VLCF responses to the corresponding agonist, but not to any other agonist. PCT inevitably prevented the VLCF responses to all three agonists. Thus these PATs selectively blocked the stimulatory action of corresponding agonists on the VLCF terminals via mechanisms that are distinct from those of PCT. PAT may become a novel intervention for studying the pharmacological modulation of VLCFs.
Collapse
Affiliation(s)
- Yu-Jung Lin
- Institute of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | | | | | | | | | | |
Collapse
|
11
|
Vagal afferent controls of feeding: a possible role for gastrointestinal BDNF. Clin Auton Res 2012; 23:15-31. [PMID: 22717678 DOI: 10.1007/s10286-012-0170-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 05/24/2012] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Vagal gastrointestinal (GI) afferents do not appear to contribute to long-term controls of feeding, despite downstream connections that could support such a role. This view is largely attributable to a lack of evidence for long-term effects, especially the failure of vagal afferent lesions to produce hyperphagia or obesity. AIMS Here, the possibility is evaluated that "side effects" of vagal lesion methods resulting largely from complexities of vagal organization would probably suppress long-term effects. Criteria based on knowledge of vagal organization were utilized to critique and compare vagal lesion methods and to interpret their effects on GI function, feeding and body weight. RESULTS AND CONCLUSIONS This analysis suggested that it was premature to eliminate a long-term vagal GI afferent role based on the effects of these lesions and highlighted aspects of vagal organization that must be addressed to reduce the problematic side effects of vagal lesions. The potential of "genetic" lesions that alter vagal sensory development to address these aspects, examination of the feasibility of this approach, and the properties of brain-derived neurotrophic factor (BDNF) that made it an attractive candidate for application of this approach are described. BDNF knockout from GI smooth muscle unexpectedly demonstrated substantial overeating and weight gain associated with increased meal size and frequency. The decay of eating rate during a scheduled meal was also reduced. However, meal-induced c-Fos activation was increased in the dorsal motor nucleus of the vagus, suggesting that the effect on eating rate was due to augmentation of GI reflexes by vagal afferents or other neural systems.
Collapse
|
12
|
Tavakkolizadeh A. Role of vagal fibers in weight control and nutrient absorption. J Surg Res 2012; 174:85-7. [PMID: 21435656 DOI: 10.1016/j.jss.2011.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 12/28/2010] [Accepted: 02/01/2011] [Indexed: 10/18/2022]
Affiliation(s)
- Ali Tavakkolizadeh
- Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| |
Collapse
|
13
|
Stearns AT, Balakrishnan A, Radmanesh A, Ashley SW, Rhoads DB, Tavakkolizadeh A. Relative contributions of afferent vagal fibers to resistance to diet-induced obesity. Dig Dis Sci 2012; 57:1281-90. [PMID: 22138962 PMCID: PMC4111149 DOI: 10.1007/s10620-011-1968-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 11/02/2011] [Indexed: 12/09/2022]
Abstract
BACKGROUND We previously demonstrated vagal neural pathways, specifically subdiaphragmatic afferent fibers, regulate expression of the intestinal sodium-glucose cotransporter SGLT1, the intestinal transporter responsible for absorption of dietary glucose. We hypothesized targeting this pathway could be a novel therapy for obesity. We therefore tested the impact of disrupting vagal signaling by total vagotomy or selective vagal de-afferentation on weight gain and fat content in diet-induced obese rats. METHODS Male Sprague-Dawley rats (n = 5-8) underwent truncal vagotomy, selective vagal de-afferentation with capsaicin, or sham procedure. Animals were maintained for 11 months on a high-caloric Western diet. Abdominal visceral fat content was assessed by magnetic resonance imaging together with weight of fat pads at harvest. Glucose homeostasis was assessed by fasting blood glucose and HbA1C. Jejunal SGLT1 gene expression was assessed by qPCR and immunoblotting and function by glucose uptake in everted jejunal sleeves. RESULTS At 11-months, vagotomized rats weighed 19% less (P = 0.003) and de-afferented rats 7% less (P = 0.19) than shams. Vagotomized and de-afferented animals had 52% (P < 0.0001) and 18% reduction (P = 0.039) in visceral abdominal fat, respectively. There were no changes in blood glucose or glycemic indexes. SGLT1 mRNA, protein and function were unchanged across all cohorts at 11-months postoperatively. CONCLUSIONS Truncal vagotomy led to significant reductions in both diet-induced weight gain and visceral abdominal fat deposition. Vagal de-afferentation led to a more modest, but clinically and statistically significant, reduction in visceral abdominal fat. As increased visceral abdominal fat is associated with excess morbidity and mortality, vagal de-afferentation may be a useful adjunct in bariatric surgery.
Collapse
Affiliation(s)
- A. T. Stearns
- Department of Surgery, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA. Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, UK
| | - A. Balakrishnan
- Department of Surgery, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA. Division of Gastroenterology, School of Clinical Sciences, University of Liverpool, Crown Street, Liverpool L69 3GE, UK
| | - A. Radmanesh
- Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
| | - S. W. Ashley
- Department of Surgery, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
| | - D. B. Rhoads
- Pediatric Endocrine Unit, MassGeneral Hospital for Children, Harvard Medical School, Fruit Street, Boston, MA 02114, USA
| | - A. Tavakkolizadeh
- Department of Surgery, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
| |
Collapse
|
14
|
Mourad FH, Saadé NE. Neural regulation of intestinal nutrient absorption. Prog Neurobiol 2011; 95:149-62. [PMID: 21854830 DOI: 10.1016/j.pneurobio.2011.07.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 04/28/2011] [Accepted: 07/20/2011] [Indexed: 12/17/2022]
Abstract
The nervous system and the gastrointestinal (GI) tract share several common features including reciprocal interconnections and several neurotransmitters and peptides known as gut peptides, neuropeptides or hormones. The processes of digestion, secretion of digestive enzymes and then absorption are regulated by the neuro-endocrine system. Luminal glucose enhances its own absorption through a neuronal reflex that involves capsaicin sensitive primary afferent (CSPA) fibres. Absorbed glucose stimulates insulin release that activates hepatoenteric neural pathways leading to an increase in the expression of glucose transporters. Adrenergic innervation increases glucose absorption through α1 and β receptors and decreases absorption through activation of α2 receptors. The vagus nerve plays an important role in the regulation of diurnal variation in transporter expression and in anticipation to food intake. Vagal CSPAs exert tonic inhibitory effects on amino acid absorption. It also plays an important role in the mediation of the inhibitory effect of intestinal amino acids on their own absorption at the level of proximal or distal segment. However, chronic extrinsic denervation leads to a decrease in intestinal amino acid absorption. Conversely, adrenergic agonists as well as activation of CSPA fibres enhance peptides uptake through the peptide transporter PEPT1. Finally, intestinal innervation plays a minimal role in the absorption of fat digestion products. Intestinal absorption of nutrients is a basic vital mechanism that depends essentially on the function of intestinal mucosa. However, intrinsic and extrinsic neural mechanisms that rely on several redundant loops are involved in immediate and long-term control of the outcome of intestinal function.
Collapse
Affiliation(s)
- Fadi H Mourad
- Department of Internal Medicine, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.
| | | |
Collapse
|
15
|
Young RL. Sensing via intestinal sweet taste pathways. Front Neurosci 2011; 5:23. [PMID: 21519398 PMCID: PMC3080736 DOI: 10.3389/fnins.2011.00023] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2010] [Accepted: 02/10/2011] [Indexed: 12/15/2022] Open
Abstract
The detection of nutrients in the gastrointestinal (GI) tract is of fundamental significance to the control of motility, glycemia and energy intake, and yet we barely know the most fundamental aspects of this process. This is in stark contrast to the mechanisms underlying the detection of lingual taste, which have been increasingly well characterized in recent years, and which provide an excellent starting point for characterizing nutrient detection in the intestine. This review focuses on the form and function of sweet taste transduction mechanisms identified in the intestinal tract; it does not focus on sensors for fatty acids or proteins. It examines the intestinal cell types equipped with sweet taste transduction molecules in animals and humans, their location, and potential signals that transduce the presence of nutrients to neural pathways involved in reflex control of GI motility.
Collapse
Affiliation(s)
- Richard L Young
- Discipline of Medicine, School of Medicine, University of Adelaide Adelaide, SA, Australia
| |
Collapse
|
16
|
Culnan DM, Albaugh V, Sun M, Lynch CJ, Lang CH, Cooney RN. Ileal interposition improves glucose tolerance and insulin sensitivity in the obese Zucker rat. Am J Physiol Gastrointest Liver Physiol 2010; 299:G751-60. [PMID: 20634437 PMCID: PMC2950685 DOI: 10.1152/ajpgi.00525.2009] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The hindgut hypothesis posits improvements in Type 2 diabetes after gastric bypass surgery are due to enhanced delivery of undigested nutrients to the ileum, which increase incretin production and insulin sensitivity. The present study investigates the effect of ileal interposition (IT), surgically relocating a segment of distal ileum to the proximal jejunum, on glucose tolerance, insulin sensitivity, and glucose transport in the obese Zucker rat. Two groups of obese Zucker rats were studied: IT and sham surgery ad libitum fed (controls). Changes in food intake, body weight and composition, glucose tolerance, insulin sensitivity and tissue glucose uptake, and insulin signaling as well as plasma concentrations of glucagon-like peptide-1 and glucose-dependent insulinotropic peptide were measured. The IT procedure did not significantly alter food intake, body weight, or composition. Obese Zucker rats demonstrated improved glucose tolerance 3 wk after IT compared with the control group (P < 0.05). Euglycemic, hyperinsulinemic clamp and 1-[(14)C]-2-deoxyglucose tracer studies indicate that IT improves whole body glucose disposal, insulin-stimulated glucose uptake, and the ratio of phospho- to total Akt (P < 0.01 vs. control) in striated muscle. After oral glucose, the plasma concentration of glucagon-like peptide-1 was increased, whereas GIP was decreased following IT. Enhanced nutrient delivery to the ileum after IT improves glucose tolerance, insulin sensitivity and muscle glucose uptake without altering food intake, body weight, or composition. These findings support the concept that anatomic and endocrine alterations in gut function play a role in the improvements in glucose homeostasis after the IT procedure.
Collapse
Affiliation(s)
| | - Vance Albaugh
- 2Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | | | - Christopher J. Lynch
- 2Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Charles H. Lang
- Departments of 1Surgery and ,2Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Robert N. Cooney
- Departments of 1Surgery and ,2Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| |
Collapse
|
17
|
Rapid upregulation of sodium-glucose transporter SGLT1 in response to intestinal sweet taste stimulation. Ann Surg 2010; 251:865-71. [PMID: 20395849 DOI: 10.1097/sla.0b013e3181d96e1f] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVE We set out to examine the short-term regulation of the intestinal sodium/glucose cotransporter SGLT1 by its substrate glucose and sweet taste analogs. SUMMARY BACKGROUND DATA Intestinal SGLT1 is a putative target for antidiabetic therapy; however, its physiological regulation is incompletely understood, limiting its application as a pharmacological target. While it is clearly regulated by dietary composition over a period of days, its short-term regulation by nutrients is unknown. METHODS Sprague-Dawley rats were anesthetized, and the duodenum cannulated. D-glucose, D-fructose, saccharin, D-mannitol, and water were infused for 3 hours, before harvest of proximal jejunum for SGLT1 analysis with Western blotting and quantitative polymerase chain reaction. In further experiments, the receptor region was identified by D-glucose infusion of isolated regions. Lastly, the vagus was de-afferented with capsaicin, and 5HT3-receptor activation of vagal afferents inhibited using ondansetron, before repeating experiments using water or D-glucose infusion. RESULTS Infusion of D-glucose led to 2.9-fold up-regulation in SGLT1 compared with water or iso-osmotic D-mannitol; this effect was replicated by D-fructose or saccharin. This response was strongest following isolated infusions of duodenum and proximal jejunum, with a blunted effect distally; topography matched the expression profile of sweet taste receptor T1R2/T1R3. The reflex was abolished by capsaicin pretreatment, and blunted by ondansetron. CONCLUSIONS The agonist response implicates the luminal-based sweet-taste receptor T1R2/T1R3, with the reflex apparently involving vagal afferents. The proximal nature of the sensor coincides with the excluded biliopancreatic limb in Roux-en-Y gastric bypass, and this may provide a novel explanation for the antidiabetic effect of this procedure.
Collapse
|
18
|
Balakrishnan A, Stearns AT, Ashley SW, Tavakkolizadeh A, Rhoads DB. Restricted feeding phase shifts clock gene and sodium glucose cotransporter 1 (SGLT1) expression in rats. J Nutr 2010; 140:908-14. [PMID: 20200113 PMCID: PMC2855260 DOI: 10.3945/jn.109.116749] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The intestine exhibits striking diurnal rhythmicity in glucose uptake, mediated by the sodium glucose cotransporter (SGLT1); however, regulatory pathways for these rhythms remain incompletely characterized. We hypothesized that SGLT1 rhythmicity is linked to the circadian clock. To investigate this, we examined rhythmicity of Sglt1 and individual clock genes in rats that consumed food ad libitum (AL). We further compared phase shifts of Sglt1 and clock genes in a second group of rats following restricted feeding to either the dark (DF) or light (LF) phase. Rats fed during the DF were pair-fed to rats fed during the LF. Jejunal mucosa was harvested across the diurnal period to generate expression profiles of Sglt1 and clock genes Clock, Bmal1 (brain-muscle Arnt-like 1), ReverbA/B, Per(Period) 1/2, and Cry (Cryptochrome) 1/2. All clock genes were rhythmic in AL rats (P < 0.05). Sglt1 also exhibited diurnal rhythmicity, with peak expression preceding nutrient arrival (P < 0.05). Light-restricted feeding shifted the expression rhythms of Sglt1 and most clock genes (Bmal1, ReverbA and B, Per1, Per2, and Cry1) compared with dark-restricted feeding (P < 0.05). The Sglt1 rhythm shifted in parallel with rhythms of Per1 and ReverbB. These effects of restricted feeding highlight luminal nutrients as a key Zeitgeber in the intestine, capable of simultaneously shifting the phases of transporter and clock gene expression, and suggest a role for clock genes in regulating Sglt1 and therefore glucose uptake. Understanding the regulatory cues governing rhythms in intestinal function may allow new therapeutic options for conditions of dysregulated absorption such as diabetes and obesity.
Collapse
Affiliation(s)
- Anita Balakrishnan
- Department of Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
| | - Adam T. Stearns
- Department of Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115; School of Clinical Sciences, Division of Gastroenterology, University of Liverpool, Liverpool L69 3GE, United Kingdom; Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 2JD, United Kingdom; Pediatric Endocrine Unit, MassGeneral Hospital for Children and Harvard Medical School, Boston, MA 02114
| | - Stanley W. Ashley
- Department of Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115; School of Clinical Sciences, Division of Gastroenterology, University of Liverpool, Liverpool L69 3GE, United Kingdom; Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 2JD, United Kingdom; Pediatric Endocrine Unit, MassGeneral Hospital for Children and Harvard Medical School, Boston, MA 02114
| | - Ali Tavakkolizadeh
- Department of Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115; School of Clinical Sciences, Division of Gastroenterology, University of Liverpool, Liverpool L69 3GE, United Kingdom; Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 2JD, United Kingdom; Pediatric Endocrine Unit, MassGeneral Hospital for Children and Harvard Medical School, Boston, MA 02114
| | - David B. Rhoads
- Department of Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115; School of Clinical Sciences, Division of Gastroenterology, University of Liverpool, Liverpool L69 3GE, United Kingdom; Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 2JD, United Kingdom; Pediatric Endocrine Unit, MassGeneral Hospital for Children and Harvard Medical School, Boston, MA 02114,To whom correspondence should be addressed. E-mail: and
| |
Collapse
|
19
|
Qandeel HG, Alonso F, Hernandez DJ, Duenes JA, Zheng Y, Scow JS, Sarr MG. Role of vagal innervation in diurnal rhythm of intestinal peptide transporter 1 (PEPT1). J Gastrointest Surg 2009; 13:1976-85. [PMID: 19707837 PMCID: PMC2830643 DOI: 10.1007/s11605-009-0984-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Accepted: 07/24/2009] [Indexed: 01/31/2023]
Abstract
BACKGROUND Protein is absorbed predominantly as di/tripeptides via H(+)/peptide cotransporter-1 (PEPT1). We demonstrated previously diurnal variations in expression and function of duodenal and jejunal but not ileal PEPT1; neural regulation of this pattern is unexplored. HYPOTHESIS Complete abdominal vagotomy abolishes diurnal variations in gene expression and transport function of PEPT1. METHODS Twenty-four rats maintained in a 12-h light/dark room [6AM-6PM] underwent abdominal vagotomy; 24 other rats were controls. Four weeks later, mucosal levels of mRNA and protein were measured at 9AM, 3PM, 9PM, and 3AM (n = 6 each) by quantitative real-time PCR and Western blots, respectively; transporter-mediated uptake of dipeptide (Gly-Sar) was measured by the everted-sleeve technique. RESULTS Diurnal variation in mRNA, as in controls, was retained post-vagotomy in duodenum and jejunum (peak at 3PM, p < 0.05) but not in ileum. Diurnal variations in expression of protein and Gly-Sar uptake, however, were absent post-vagotomy (p > 0.3). Similar to controls, maximal uptake was in jejunum after vagotomy (V (max), nmol/cm/min: jejunum vs. duodenum and ileum; 163 vs. 88 and 71 at 3AM; p < 0.04); K (m) remained unchanged. CONCLUSIONS Vagal innervation appears to mediate in part diurnal variations in protein expression and transport function of PEPT1, but not diurnal variation in mRNA expression of PEPT1.
Collapse
Affiliation(s)
- Hisham G Qandeel
- Gastrointestinal Research Unit and Department of Surgery, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA
| | | | | | | | | | | | | |
Collapse
|
20
|
Stearns AT, Balakrishnan A, Tavakkolizadeh A. Impact of Roux-en-Y gastric bypass surgery on rat intestinal glucose transport. Am J Physiol Gastrointest Liver Physiol 2009; 297:G950-7. [PMID: 20501442 PMCID: PMC2777457 DOI: 10.1152/ajpgi.00253.2009] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Roux-en-Y gastric bypass (RYGB) has become the gold-standard bariatric procedure, partly because of the rapid resolution of accompanying diabetes. There is increasing evidence this is mediated by duodenal exclusion. We hypothesize that duodenal exclusion suppresses intestinal Na(+)/glucose cotransporter SGLT1-mediated glucose transport, improving glucose handling, and aimed to test this in a rodent RYGB model. Sprague-Dawley rats underwent sham procedure or duodenal exclusion by RYGB (10 cm Roux, 16 cm biliopancreatic limbs). Animals were maintained for 3 wk on a Western diet, before harvest at 10 AM, 4 PM, and 10 PM. Sections were taken from each limb for hematoxylin and eosin staining, and morphological assessment was performed. Functional glucose uptake studies, along with Western blotting and quantitative PCR, were performed on Roux limb. Histology showed morphometric changes in Roux and common limbs, with increase in villus height and crypt depth compared with BP and sham jejunum. Despite this, glucose transport was reduced by up to 68% (P < 0.001) in the Roux limb compared with sham jejunum. Normal diurnal rhythms in glucose uptake were ablated. This occurred at a posttranscriptional level, with little change in message but appearance of different weight species of Sglt1 on Western blotting. We have shown duodenal exclusion significantly influences both intestinal structure and glucose transport function, with glucose absorptive capacity reduced after RYGB. This provides a novel mechanistic explanation for some of the antidiabetic effects of RYGB.
Collapse
Affiliation(s)
- Adam T. Stearns
- 1Department of Surgery, Brigham and Women's Hospital/Harvard Medical School, Boston, Massachusetts; ,2Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom; and
| | - Anita Balakrishnan
- 1Department of Surgery, Brigham and Women's Hospital/Harvard Medical School, Boston, Massachusetts; ,3School of Clinical Sciences, Division of Gastroenterology, University of Liverpool, Liverpool, United Kingdom
| | - Ali Tavakkolizadeh
- 1Department of Surgery, Brigham and Women's Hospital/Harvard Medical School, Boston, Massachusetts;
| |
Collapse
|
21
|
Circadian variation in intestinal dihydropyrimidine dehydrogenase (DPD) expression: A potential mechanism for benefits of 5FU chrono-chemotherapy. Surgery 2009; 146:269-73. [DOI: 10.1016/j.surg.2009.05.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Accepted: 05/08/2009] [Indexed: 11/19/2022]
|
22
|
Stearns AT, Balakrishnan A, Rhoads DB, Ashley SW, Tavakkolizadeh A. Diurnal expression of the rat intestinal sodium-glucose cotransporter 1 (SGLT1) is independent of local luminal factors. Surgery 2009; 145:294-302. [PMID: 19231582 DOI: 10.1016/j.surg.2008.11.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Accepted: 11/13/2008] [Indexed: 11/29/2022]
Abstract
BACKGROUND The intestinal sodium-glucose cotransporter 1 (SGLT1) is responsible for all secondary active transport of dietary glucose, and it presents a potential therapeutic target for obesity and diabetes. SGLT1 expression varies with a profound diurnal rhythm, matching expression to nutrient intake. The mechanisms entraining this rhythm remain unknown. We investigated the role of local nutrient signals in diurnal SGLT1 entrainment. METHODS Male Sprague-Dawley rats, which were acclimatized to a 12:12 light:dark cycle, underwent laparotomy with formation of isolated proximal jejunal loops (Thiry-Vella loops). Animals were recovered for 10 days before harvesting at 4 6-h intervals (Zeitgeber times ZT3, ZT9, ZT15, and ZT21, where ZT0 is lights on; n = 6-8). SGLT1 expression was assessed in protein, and mRNA extracts of mucosa were harvested from both isolated loops (LOOP) and remnant jejunum (JEJ). RESULTS Isolated loops were healthy but atrophic with minimal changes to villus architecture. A normal anticipatory rhythm was observed in Sglt1 transcription in both LOOP and JEJ, with the peak signal at ZT9 (2.7-fold, P < .001). Normal diurnal rhythms were also observed in the protein signal, with peak expression in both LOOP and JEJ at ZT9 to 15 (2.1-fold, P < .05). However, an additional more mobile polypeptide band was also observed in all LOOP samples but not in JEJ samples (61 kDa vs 69 kDa). Enzymatic deglycosylation suggested this to be deglycosylated SGLT1. CONCLUSION The persistence of SGLT1 rhythmicity in isolated loops indicates that diurnal induction is independent of local luminal nutrient delivery, and it suggests a reliance on systemic entrainment pathways. However, local luminal signals may regulate glycosylation and, therefore, the posttranslational handling of SGLT1.
Collapse
Affiliation(s)
- Adam T Stearns
- Department of Surgery, Brigham and Women's Hospital, Boston, MA 02115, USA
| | | | | | | | | |
Collapse
|
23
|
Stearns AT, Balakrishnan A, Rhoads DB, Ashley SW, Tavakkolizadeh A. Diurnal rhythmicity in the transcription of jejunal drug transporters. J Pharmacol Sci 2008; 108:144-8. [PMID: 18787306 DOI: 10.1254/jphs.08100sc] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Intestinal drug efflux proteins play a major role in the pharmacokinetics of many drugs. We assessed diurnal rhythmicity in the expression of ten major drug transporters. We acquired male Sprague-Dawley rats and harvested jejunal mucosa at 3-h intervals across a 24-h period. qPCR was performed for ten transporters: Mdr1, Mdr3, Mrp1 - 3, Mct1, Brcp, Pept1, Octn2, and Oatp-b. Rhythmicity was assessed with the cosinor procedure. Diurnal rhythmicity was observed for Mdr1, Mct1, Mrp2, Pept1, and Bcrp (1.6 - 5.4-fold-changes). Acrophases occurred during fasting hours. We conclude that many drug transporters display profound diurnal rhythms in transcription, which may underlie diurnal rhythms in drug pharmacokinetics.
Collapse
Affiliation(s)
- Adam T Stearns
- Department of Surgery, Brigham & Women's Hospital/Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
| | | | | | | | | |
Collapse
|