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Satoh H, Akiba Y, Urushidani T, Kaunitz JD. Cholecystokinin-Induced Duodenogastric Bile Reflux Increases the Severity of Indomethacin-Induced Gastric Antral Ulcers in Re-fed Mice. Dig Dis Sci 2024; 69:1156-1168. [PMID: 38448762 DOI: 10.1007/s10620-024-08352-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 02/09/2024] [Indexed: 03/08/2024]
Abstract
BACKGROUND/AIMS We examined the involvement of cholecystokinin (CCK) in the exacerbation of indomethacin (IND)-induced gastric antral ulcers by gastroparesis caused by atropine or dopamine in mice. METHODS Male mice were fed for 2 h (re-feeding) following a 22-h fast. Indomethacin (IND; 10 mg/kg, s.c.) was administered after re-feeding; gastric lesions were examined 24 h after IND treatment. In another experiment, mice were fed for 2 h after a 22-h fast, after which the stomachs were removed 1.5 h after the end of the feeding period. Antral lesions, the amount of gastric contents, and the gastric luminal bile acids concentration were measured with or without the administration of the pro- and antimotility drugs CCK-octapeptide (CCK-8), atropine, dopamine, SR57227 (5-HT3 receptor agonist), apomorphine, lorglumide (CCK1 receptor antagonist), ondansetron, and haloperidol alone and in combination. RESULTS IND produced severe lesions only in the gastric antrum in re-fed mice. CCK-8, atropine, dopamine, SR57227 and apomorphine administered just after re-feeding increased bile reflux and worsened IND-induced antral lesions. These effects were significantly prevented by pretreatment with lorglumide. Although atropine and dopamine also increased the amount of gastric content, lorglumide had no effect on the delayed gastric emptying provoked by atropine and dopamine. Both ondansetron and haloperidol significantly inhibited the increase of bile reflux and the exacerbation of antral lesions induced by atropine and dopamine, respectively, but did not affect the effects of CCK-8. CONCLUSIONS These results suggest that CCK-CCK1 receptor signal increases bile reflux during gastroparesis induced by atropine and dopamine, exacerbating IND-induced antral ulcers.
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Affiliation(s)
- Hiroshi Satoh
- Department of Pathophysiology, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts, Kodo, Kyotanabe, Kyoto, 610-0395, Japan.
| | - Yasutada Akiba
- Greater Los Angeles Veterans Affairs Healthcare System, B114, R217, West LA VAMC, 11301 Wilshire Blvd., Los Angeles, CA, 90073, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90025, USA
| | - Tetsuro Urushidani
- Department of Pathophysiology, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts, Kodo, Kyotanabe, Kyoto, 610-0395, Japan
| | - Jonathan D Kaunitz
- Greater Los Angeles Veterans Affairs Healthcare System, B114, R217, West LA VAMC, 11301 Wilshire Blvd., Los Angeles, CA, 90073, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90025, USA
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Satoh H, Akiba Y, Urushidani T, Kaunitz JD. Gastroparesis Worsens Indomethacin-Induced Gastric Antral Ulcers by Bile Reflux via Activation of 5-HT 3 and Dopamine D 2 Receptors in Mice. Dig Dis Sci 2023; 68:3886-3901. [PMID: 37632663 DOI: 10.1007/s10620-023-08086-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 08/16/2023] [Indexed: 08/28/2023]
Abstract
BACKGROUND/AIMS We examined the contributions of gastric emptying and duodenogastric bile reflux in the formation of gastric antral ulcers induced by NSAIDs in mice. METHODS We used the murine re-fed indomethacin (IND) experimental ulcer model. Outcome measures included the appearance of gastric lesions 24 h after IND treatment and the assessment of gastric contents and the concentration of bile acids 1.5 h after re-feeding. The effects of atropine, dopamine, SR57227 (5-HT3 receptor agonist), apomorphine, ondansetron, haloperidol, and dietary taurocholate and cholestyramine were also examined. RESULTS IND (10 mg/kg, s.c.) induced severe lesions only in the gastric antrum in the re-fed model. The antral lesion index and the amount of food intake during the 2-h refeeding period were positively correlated. Atropine and dopamine delayed gastric emptying, increased bile reflux, and worsened IND-induced antral lesions. SR57227 and apomorphine worsened antral lesions with increased bile reflux. These effects were prevented by the anti-emetic drugs ondansetron and haloperidol, respectively. The anti-emetic drugs markedly decreased the severity of antral lesions and the increase of bile reflux induced by atropine or dopamine without affecting delayed gastric emptying. Antral lesions induced by IND were increased by dietary taurocholate but decreased by the addition of the bile acid sequestrant cholestyramine. CONCLUSIONS These results suggest that gastroparesis induced by atropine or dopamine worsens NSAID-induced gastric antral ulcers by increasing duodenogastric bile reflux via activation of 5-HT3 and dopamine D2 receptors.
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Affiliation(s)
- Hiroshi Satoh
- Department of Pathophysiology, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts, Kodo, Kyotanabe, Kyoto, 610-0395, Japan.
| | - Yasutada Akiba
- Greater Los Angeles Veterans Affairs Healthcare System, B114, R217, West LA VAMC, 11301 Wilshire Blvd., Los Angeles, CA, 90073, USA
- Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90025, USA
| | - Tetsuro Urushidani
- Department of Pathophysiology, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts, Kodo, Kyotanabe, Kyoto, 610-0395, Japan
| | - Jonathan D Kaunitz
- Greater Los Angeles Veterans Affairs Healthcare System, B114, R217, West LA VAMC, 11301 Wilshire Blvd., Los Angeles, CA, 90073, USA
- Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90025, USA
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Kaunitz JD, Bejjani A. Very Unstable Genetics: How the Confluence of Microsatellite Instability and Immunotherapy Revolutionized the Treatment of Colon Cancer. Dig Dis Sci 2023; 68:3494-3503. [PMID: 37402981 DOI: 10.1007/s10620-023-08007-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/19/2023] [Indexed: 07/06/2023]
Affiliation(s)
- Jonathan D Kaunitz
- Medical Service, Section of Gastroenterology, Greater Los Angeles VAMC, Los Angeles, CA, USA.
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
| | - Anthony Bejjani
- Medical Service, Section of Hematology Oncology, Greater Los Angeles VAMC, Los Angeles, CA, USA
- Division of Hematology-Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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Bahdi F, Kaunitz JD. Massive Post-polypectomy Bleeding in a Patient on Apixaban Reversed with Andexanet Alfa. Dig Dis Sci 2023:10.1007/s10620-023-07963-9. [PMID: 37204554 DOI: 10.1007/s10620-023-07963-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 04/27/2023] [Indexed: 05/20/2023]
Affiliation(s)
- Firas Bahdi
- Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA
- Medical Service, Gastroenterology Section, Greater Los Angeles VA Healthcare System, Los Angeles, CA, 90073, USA
| | - Jonathan D Kaunitz
- Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA.
- Medical Service, Gastroenterology Section, Greater Los Angeles VA Healthcare System, Los Angeles, CA, 90073, USA.
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Kaunitz JD, Hollander D. Revisiting the Stool Microbiome: Intestinal Paracellular Permeability Connection. Gastroenterology 2023; 164:1024-1025. [PMID: 36549372 DOI: 10.1053/j.gastro.2022.12.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/02/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022]
Affiliation(s)
- Jonathan D Kaunitz
- Section of Gastroenterology, Medical Service, Greater Los Angeles VA Healthcare System and, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Daniel Hollander
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California
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Tsai K, Inoue K, McClean M, Kaunitz JD, Akiba Y, Lee ML, Neverova NV, Currier JW, Ebrahimi R, Bashir MT, Leung AM. Iodine contrast exposure and incident COVID-19 infection. Front Med (Lausanne) 2022; 9:1033601. [DOI: 10.3389/fmed.2022.1033601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 11/18/2022] [Indexed: 12/04/2022] Open
Abstract
BackgroundIodine and particularly its oxidated forms have long been recognized for its effective antiseptic properties. Limited in vitro and in vivo data suggest that iodine exposure may rapidly inactivate, reduce transmission, and reduce infectivity of SARS-CoV-2. We hypothesized that iodine exposure may be associated with decreased incident COVID-19 infection.MethodsA retrospective population-level cohort analysis was performed of the U.S. Veterans Health Administration between 1 March 2020 and 31 December 2020, before the widespread availability of vaccines against SARS-CoV-2. Multivariable logistic regression models estimated the adjusted odds ratios (OR) and 95% confidence intervals (CI) of the associations between iodinated contrast exposure and incident COVID-19 infection, adjusting for age, sex, race/ethnicity, place of residence, socioeconomic status, and insurance status.Results530,942 COVID-19 tests from 333,841 Veterans (mean ± SD age, 62.7 ± 15.2 years; 90.2% men; 61.9% non-Hispanic Whites) were analyzed, of whom 9% had received iodinated contrast ≤60 days of a COVID-19 test. Iodine exposure was associated with decreased incident COVID-19 test positivity (OR, 0.75 95% CI, 0.71–0.78). In stratified analyses, the associations between iodinated contrast use and decreased COVID-19 infection risk did not differ by age, sex, and race/ethnicity.ConclusionIodine exposure may be protective against incident COVID-19 infection. Weighed against the risks of supraphysiologic iodine intake, dietary, and supplemental iodine nutrition not to exceed its Tolerable Upper Limit may confer an antimicrobial benefit against SARS-CoV-2. A safe but antimicrobial level of iodine supplementation may be considered in susceptible individuals, particularly in geographic regions where effective COVID-19 vaccines are not yet readily available.
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Kaunitz JD, Mandelkern M, Fowler JS. It's Not What You Take Up, It's What You Keep: How Discoveries from Diverse Disciplines Directed the Development of the FDG PET/CT Scan. Dig Dis Sci 2022; 67:4620-4632. [PMID: 35908123 DOI: 10.1007/s10620-022-07615-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/27/2022] [Indexed: 12/14/2022]
Abstract
Although imaging glucose metabolism with positron emission tomography combined with X-ray CT (FDG-PET/CT) has become a standard diagnostic modality for the discovery and surveillance of malignant tumors and inflammatory processes, its origins extend back to more than a century of notable discoveries in the fields of inorganic and organic chemistry, nuclear physics, mathematics, biochemistry, solute transport physiology, metabolism, and imaging, accomplished by pioneering and driven investigators, of whom at least ten were recipients of the Nobel Prize. These tangled and diverse roots eventually coalesced into the FDG-PET/CT method, that through its many favorable characteristics inherent in the isotope used (18F), the accurate imaging derived from coincidence detection of positron annihilation radiation combined with computed tomography, and the metabolic trapping of 2-deoxy-2-[18F]fluoro-D-glucose (FDG) in tissues, provides safety, sensitivity, and specificity for tumor and inflammation detection. The authors hope that this article will increase the appreciation among its readers of the insight, creativity, persistence, and drive of the many investigators who made this technique possible. This article is followed by a review of the many applications of FDG-PET/CT to the gastrointestinal tract and hepatobiliary system (Mandelkern in Dig Dis Sci 2022).
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Affiliation(s)
- Jonathan D Kaunitz
- Medical Service, Greater Los Angeles VAMC, Los Angeles, CA, USA. .,Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
| | - Mark Mandelkern
- Nuclear Medicine Service, Greater Los Angeles VAMC, Los Angeles, CA, USA.,Department of Physics, University of California, Irvine, Irvine, CA, USA
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Huang X, Oshima T, Akiba Y, Yoshimoto T, Chen J, Taki M, Tomita T, Fukui H, Kaunitz JD, Miwa H. Duodenal cholinergic tuft cell number is increased in functional dyspepsia. Neurogastroenterol Motil 2022; 34:e14378. [PMID: 35388579 DOI: 10.1111/nmo.14378] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 02/15/2022] [Accepted: 03/28/2022] [Indexed: 12/13/2022]
Abstract
BACKGROUND Low-grade duodenal inflammation has recently been identified in patients with functional dyspepsia (FD). Chemosensory tuft cells were reported to be associated with gastrointestinal diseases. We therefore assessed duodenal tuft cell density and microinflammation in patients with FD to determine whether these measures could serve as useful biomarkers, and also correlated tuft cell density and microinflammation in FD patients. METHODS Duodenal biopsy specimens were obtained from patients with FD and from controls. Tuft cells, eosinophils, and mast cells were immunochemically stained with specific antibodies. Tuft cells were identified by immunostaining for doublecortin-like kinase 1 (DCLK1); cholinergic tuft cells were assessed by double staining for choline acetyltransferase (ChAT) and DCLK1. Immune-type tuft cells were assessed by IL-25 mRNA expression using real-time PCR. KEY RESULTS The density of intramucosal eosinophils and mast cells was significantly higher in the duodenum of FD patients than in controls. The density of tuft cells was significantly higher in the duodenum of FD patients compared with controls, and significantly correlated with eosinophil density in the duodenum of FD patients and controls. Moreover, a fraction of ChAT-positive cells was DCLK1 positive; all duodenal DCLK1+ tuft cells were ChAT-immunoreactive in FD and in control subjects. CONCLUSIONS AND INFERENCES Cholinergic tuft cell density was higher in the duodenum of patients with FD and significantly correlated with eosinophil density. Further studies are needed to investigate the pathophysiological significance of tuft cells in FD and may provide valuable clues to the pathophysiology of FD.
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Affiliation(s)
- Xinyi Huang
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Tadayuki Oshima
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Yasutada Akiba
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, USA.,Department of Medicine, The David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California, USA
| | - Takanori Yoshimoto
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Junji Chen
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Masato Taki
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Toshihiko Tomita
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Hirokazu Fukui
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Jonathan D Kaunitz
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, USA.,Department of Medicine, The David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California, USA.,Department of Surgery, The David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California, USA
| | - Hiroto Miwa
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
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Nishii S, Akiba Y, Mizoguchi A, Kaunitz JD. LPS transport during fat absorption is inhibited in caveolin‐1 knockout murine jejunum. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r2967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Mizoguchi A, Akiba Y, Nishii S, Kaunitz JD. Medium‐chain fatty acids inhibit jejunal SGLT1 activity in vitro and suppress glucose absorption in vivo in mice. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r2974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kaunitz JD, Ganz T. AGA Clinical Practice Guidelines on the Gastrointestinal Evaluation of Iron Deficiency Anemia. Gastroenterology 2021; 161:362-365. [PMID: 33675744 DOI: 10.1053/j.gastro.2021.03.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 02/23/2021] [Accepted: 03/01/2021] [Indexed: 12/15/2022]
Affiliation(s)
- Jonathan D Kaunitz
- Medical Service, West Los Angeles VAMC, Los Angeles, California; Division of Digestive Diseases and Hepatology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Tomas Ganz
- Division of Pulmonary and Critical Care, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California; Division of Hematology-Oncology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California
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12
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Ballout J, Akiba Y, Kaunitz JD, Diener M. Short-chain fatty acid receptors involved in epithelial acetylcholine release in rat caecum. Eur J Pharmacol 2021; 906:174292. [PMID: 34216575 DOI: 10.1016/j.ejphar.2021.174292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/17/2021] [Accepted: 06/25/2021] [Indexed: 10/21/2022]
Abstract
Short-chain fatty acids (SCFAs) produced by the microbial fermentation of carbohydrates are important energy substrates for mammals. Intestinal epithelia respond to these metabolites by stimulation of anion secretion via the release of epithelial acetylcholine. The present experiments were performed to discover which of the known receptors for SCFAs are expressed in rat caecum, the most important site of fermentation within the intestine of non-ruminant mammals. Using the increase in short-circuit current (Isc) induced by anion secretion as the readout, the order of efficiency of the tested SCFAs in rat caecum was propionate > butyrate > acetate. Both synthetic high-affinity selective free fatty acid (FFA) receptor agonists 4-CMTB (FFA2 receptor) and AR420626 (FFA3 receptor) partially mimicked the effect of propionate on Isc (IProp). IProp was concentration-dependently inhibited by the FFA3 receptor antagonist β-OH-butyrate. Although no antagonist of rat FFA2 receptor is available, coadministration of the allosteric FFA2 receptor agonist 4-CMTB together with a low concentration of propionate potentiated IProp, suggesting that FFA2 receptor is involved in sensing of short-chain fatty acids as well. The expression of both receptor types was confirmed by qPCR (with FFA2 > FFA3 receptor). Immunohistochemical staining revealed the localization of FFA2 receptor in the surface epithelium and the FFA3 receptor expression predominantly in enteroendocrine cells and subepithelial nerve-like fibers. Taken together, the present results demonstrate that the anion secretion induced by the microbial metabolite propionate in rat caecum is enhanced by activation of FFA2 and FFA3 receptor expressed in different cell types within the caecal epithelium.
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Affiliation(s)
- Jasmin Ballout
- Institute for Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Germany
| | - Yasutada Akiba
- Greater Los Angeles Veterans Affairs Healthcare System, University of California Los Angeles, School of Medicine, CA, 90073, USA; Department of Medicine, University of California Los Angeles, School of Medicine, CA, 90073, USA
| | - Jonathan D Kaunitz
- Greater Los Angeles Veterans Affairs Healthcare System, University of California Los Angeles, School of Medicine, CA, 90073, USA; Department of Medicine, University of California Los Angeles, School of Medicine, CA, 90073, USA; Department of Surgery, University of California Los Angeles, School of Medicine, CA, 90073, USA
| | - Martin Diener
- Institute for Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Germany.
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Jeon Y, Leung D, Lis CA, Wang HL, Deurdulian C, Mandelkern M, Kaunitz JD. Casting a Wider NET: Is It Crohn's or Is It Neuroendocrine Tumor? Dig Dis Sci 2021; 66:1802-1806. [PMID: 33783690 DOI: 10.1007/s10620-021-06952-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/08/2021] [Indexed: 12/09/2022]
Affiliation(s)
- Yejoo Jeon
- Department of Medicine, UCLA Medical Center, David Geffen School of Medicine At UCLA, 757 Westwood Plaza, Suite 7501, Los Angeles, CA, 90095, USA.
| | - David Leung
- Department of Medicine, Scripps Mercy Hospital, San Diego, CA, USA
| | - Claire A Lis
- Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Hanlin L Wang
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Corinne Deurdulian
- Department of Radiology, West Los Angeles VA Medical Center, Los Angeles, CA, USA
| | - Mark Mandelkern
- Department of Nuclear Medicine, West Los Angeles VA Medical Center, Los Angeles, CA, USA
| | - Jonathan D Kaunitz
- Department of Medicine, UCLA Medical Center, David Geffen School of Medicine At UCLA, 757 Westwood Plaza, Suite 7501, Los Angeles, CA, 90095, USA.,Department of Internal Medicine Services, West Los Angeles VA Medical Center, Los Angeles, CA, USA.,Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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Kaunitz JD. Welcome Associate Editors Surinder Singh Rana and Rupjyoti Talukdar. Dig Dis Sci 2021; 66:655-656. [PMID: 33428041 DOI: 10.1007/s10620-020-06795-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Affiliation(s)
- Jonathan D Kaunitz
- Greater Los Angeles VA Healthcare System, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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Maruta K, Takajo T, Akiba Y, Said H, Irie E, Kato I, Kuwahara A, Kaunitz JD. GLP-2 Acutely Prevents Endotoxin-Related Increased Intestinal Paracellular Permeability in Rats. Dig Dis Sci 2020; 65:2605-2618. [PMID: 32006214 PMCID: PMC7392813 DOI: 10.1007/s10620-020-06097-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 01/20/2020] [Indexed: 01/15/2023]
Abstract
BACKGROUND Circulating endotoxin (lipopolysaccharide, LPS) increases the gut paracellular permeability. We hypothesized that glucagon-like peptide-2 (GLP-2) acutely reduces LPS-related increased intestinal paracellular permeability by a mechanism unrelated to its intestinotrophic effect. METHODS We assessed small intestinal paracellular permeability in vivo by measuring the appearance of intraduodenally perfused FITC-dextran 4000 (FD4) into the portal vein (PV) in rats 1-24 h after LPS treatment (5 mg/kg, ip). We also examined the effect of a stable GLP-2 analog teduglutide (TDG) on FD4 permeability. RESULTS FD4 movement into the PV was increased 6 h, but not 1 or 3 h after LPS treatment, with increased PV GLP-2 levels and increased mRNA expressions of proinflammatory cytokines and proglucagon in the ileal mucosa. Co-treatment with a GLP-2 receptor antagonist enhanced PV FD4 concentrations. PV FD4 concentrations 24 h after LPS were higher than FD4 concentrations 6 h after LPS, reduced by exogenous GLP-2 treatment given 6 or 12 h after LPS treatment. FD4 uptake measured 6 h after LPS was reduced by TDG 3 or 6 h after LPS treatment. TDG-associated reduced FD4 uptake was reversed by the VPAC1 antagonist PG97-269 or L-NAME, not by EGF or IGF1 receptor inhibitors. CONCLUSIONS Systemic LPS releases endogenous GLP-2, reducing LPS-related increased permeability. The therapeutic window of exogenous GLP-2 administration is at minimum within 6-12 h after LPS treatment. Exogenous GLP-2 treatment is of value in the prevention of increased paracellular permeability associated with endotoxemia.
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Affiliation(s)
- Koji Maruta
- Department of Medicine, School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Takeshi Takajo
- Department of Medicine, School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Yasutada Akiba
- Greater Los Angeles Veterans Affairs Healthcare System, West Los Angeles VA Medical Center, Bldg. 114, Suite 217, 11301 Wilshire Blvd., Los Angeles, CA 90073, USA,Department of Medicine, School of Medicine, University of California Los Angeles, Los Angeles, CA, USA,Brentwood Biomedical Research Institute, Los Angeles, CA, USA
| | - Hyder Said
- Department of Medicine, School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Emi Irie
- Greater Los Angeles Veterans Affairs Healthcare System, West Los Angeles VA Medical Center, Bldg. 114, Suite 217, 11301 Wilshire Blvd., Los Angeles, CA 90073, USA
| | - Ikuo Kato
- Department of Medical Biochemistry, Kobe Pharmaceutical University, Kobe, Japan
| | - Atsukazu Kuwahara
- Research Unit for Epithelial Physiology, Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, Japan
| | - Jonathan D. Kaunitz
- Greater Los Angeles Veterans Affairs Healthcare System, West Los Angeles VA Medical Center, Bldg. 114, Suite 217, 11301 Wilshire Blvd., Los Angeles, CA 90073, USA,Department of Medicine, School of Medicine, University of California Los Angeles, Los Angeles, CA, USA,Department of Surgery, School of Medicine, University of California Los Angeles, Los Angeles, CA, USA,Brentwood Biomedical Research Institute, Los Angeles, CA, USA
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Akiba Y, Maruta K, Takajo T, Narimatsu K, Said H, Kato I, Kuwahara A, Kaunitz JD. Lipopolysaccharides transport during fat absorption in rodent small intestine. Am J Physiol Gastrointest Liver Physiol 2020; 318:G1070-G1087. [PMID: 32390462 PMCID: PMC7311662 DOI: 10.1152/ajpgi.00079.2020] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/29/2020] [Accepted: 05/06/2020] [Indexed: 02/07/2023]
Abstract
Lipopolysaccharides (LPS) are potent pro-inflammatory molecules that enter the systemic circulation from the intestinal lumen by uncertain mechanisms. We investigated these mechanisms and the effect of exogenous glucagon-like peptide-2 (GLP-2) on LPS transport in the rodent small intestine. Transmucosal LPS transport was measured in Ussing-chambered rat jejunal mucosa. In anesthetized rats, the appearance of fluorescein isothiocyanate (FITC)-LPS into the portal vein (PV) and the mesenteric lymph was simultaneously monitored after intraduodenal perfusion of FITC-LPS with oleic acid and taurocholate (OA/TCA). In vitro, luminally applied LPS rapidly appeared in the serosal solution only with luminal OA/TCA present, inhibited by the lipid raft inhibitor methyl-β-cyclodextrin (MβCD) and the CD36 inhibitor sulfosuccinimidyl oleate (SSO), or by serosal GLP-2. In vivo, perfusion of FITC-LPS with OA/TCA rapidly increased FITC-LPS appearance into the PV, followed by a gradual increase of FITC-LPS into the lymph. Rapid PV transport was inhibited by the addition of MβCD or by SSO, whereas transport into the lymph was inhibited by chylomicron synthesis inhibition. Intraveous injection of the stable GLP-2 analog teduglutide acutely inhibited FITC-LPS transport into the PV, yet accelerated FITC-LPS transport into the lymph via Nω-nitro-l-arginine methyl ester (l-NAME)- and PG97-269-sensitive mechanisms. In vivo confocal microscopy in mouse jejunum confirmed intracellular FITC-LPS uptake with no evidence of paracellular localization. This is the first direct demonstration in vivo that luminal LPS may cross the small intestinal barrier physiologically during fat absorption via lipid raft- and CD36-mediated mechanisms, followed by predominant transport into the PV, and that teduglutide inhibits LPS uptake into the PV in vivo.NEW & NOTEWORTHY We report direct in vivo confirmation of transcellular lipopolysaccharides (LPS) uptake from the intestine into the portal vein (PV) involving CD36 and lipid rafts, with minor uptake via the canonical chylomicron pathway. The gut hormone glucagon-like peptide-2 (GLP-2) inhibited uptake into the PV. These data suggest that the bulk of LPS absorption is via the PV to the liver, helping clarify the mechanism of LPS transport into the PV as part of the "gut-liver" axis. These data do not support the paracellular transport of LPS, which has been implicated in the pathogenesis of the "leaky gut" syndrome.
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Affiliation(s)
- Yasutada Akiba
- Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, California
- Department of Medicine, University of California, School of Medicine, Los Angeles, California
- Brentwood Biomedical Research Institute, Los Angeles, California
| | - Koji Maruta
- Department of Medicine, University of California, School of Medicine, Los Angeles, California
| | - Takeshi Takajo
- Department of Medicine, University of California, School of Medicine, Los Angeles, California
| | - Kazuyuki Narimatsu
- Department of Medicine, University of California, School of Medicine, Los Angeles, California
| | - Hyder Said
- Department of Medicine, University of California, School of Medicine, Los Angeles, California
| | - Ikuo Kato
- Department of Medical Biochemistry, Kobe Pharmaceutical University, Kobe, Japan
| | - Atsukazu Kuwahara
- Research Unit for Epithelial Physiology, Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, Japan
| | - Jonathan D Kaunitz
- Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, California
- Department of Medicine, University of California, School of Medicine, Los Angeles, California
- Department of Surgery, University of California, School of Medicine, Los Angeles, California
- Brentwood Biomedical Research Institute, Los Angeles, California
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17
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Fenton RA, Murali SK, Kaji I, Akiba Y, Kaunitz JD, Kristensen TB, Poulsen SB, Dominguez Rieg JA, Rieg T. Adenylyl Cyclase 6 Expression Is Essential for Cholera Toxin-Induced Diarrhea. J Infect Dis 2020; 220:1719-1728. [PMID: 30624615 DOI: 10.1093/infdis/jiz013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 01/07/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Cholera toxin (CT)-induced diarrhea is mediated by cyclic adenosine monophosphate (cAMP)-mediated active Cl- secretion via the cystic fibrosis transmembrane conductance regulator (CFTR). Although the constitutive activation of adenylyl cyclase (AC) in response to CT is due to adenosine diphosphate ribosylation of the small G protein α-subunit activating CFTR with consequent secretory diarrhea, the AC isoform(s) involved remain unknown. METHODS We generated intestinal epithelial cell-specific adenylyl cyclase 6 (AC6) knockout mice to study its role in CT-induced diarrhea. RESULTS AC6 messenger RNA levels were the highest of all 9 membrane-bound AC isoforms in mouse intestinal epithelial cells. Intestinal epithelial-specific AC6 knockout mice (AC6loxloxVillinCre) had undetectable AC6 levels in small intestinal and colonic epithelial cells. No significant differences in fluid and food intake, plasma electrolytes, intestinal/colon anatomy and morphology, or fecal water content were observed between genotypes. Nevertheless, CT-induced fluid accumulation in vivo was completely absent in AC6loxloxVillinCre mice, associated with a lack of forskolin- and CT-induced changes in the short-circuit current (ISC) of the intestinal mucosa, impaired cAMP generation in acutely isolated small intestinal epithelial cells, and significantly impaired apical CFTR levels in response to forskolin. CONCLUSIONS AC6 is a novel target for the treatment of CT-induced diarrhea.
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Affiliation(s)
| | - Sathish K Murali
- Department of Biomedicine, Aarhus University, Denmark.,University of South Florida, Tampa
| | - Izumi Kaji
- Greater Los Angeles VA Healthcare System, California.,Department of Medicine, University of California, Los Angeles
| | - Yasutada Akiba
- Greater Los Angeles VA Healthcare System, California.,Department of Medicine, University of California, Los Angeles
| | - Jonathan D Kaunitz
- Greater Los Angeles VA Healthcare System, California.,Department of Medicine, University of California, Los Angeles
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18
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Affiliation(s)
- Daniel Hollander
- Division of Digestive Diseases, Department of Medicine, UCLA School of Medicine, Los Angeles, CA 90024, USA
| | - Jonathan D. Kaunitz
- Division of Digestive Diseases, Department of Medicine, UCLA School of Medicine, Los Angeles, CA 90024, USA,Department of Surgery, UCLA School of Medicine, Los Angeles, CA 90024, USA,Gastroenterology Section, Medical Service, West Los Angeles VAMC, Los Angeles, CA 90073, USA
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19
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Akiba Y, Kaunitz JD. Sodium Caprate Increases Electrogenic Anion Secretion via TRPV4, ATP‐P2Y and VIP‐VPAC1 Pathways in Rat Duodenum. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.02747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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20
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Akiba Y, Kaunitz JD. Sodium Caprate Enhances Transcellular LPS Transport via Clathrin‐Mediated Endocytosis in Rat Jejunum. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.02184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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21
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Affiliation(s)
- Jonathan D. Kaunitz
- Medical Service, West Los Angeles VAMC and Departments of Medicine and Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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22
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Affiliation(s)
- Jonathan D Kaunitz
- Medical Service, West Los Angeles VAMC, Los Angeles, USA.
- Departments of Medicine and Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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23
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Kaunitz JD, Akiba Y. Control of Intestinal Epithelial Proliferation and Differentiation: The Microbiome, Enteroendocrine L Cells, Telocytes, Enteric Nerves, and GLP, Too. Dig Dis Sci 2019; 64:2709-2716. [PMID: 31435858 PMCID: PMC7211432 DOI: 10.1007/s10620-019-05778-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Jonathan D. Kaunitz
- Medical Service, West Los Angeles VAMC, Los Angeles, CA, USA,Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA,Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Yasutada Akiba
- Research Service, West Los Angeles VAMC, Los Angeles, CA, USA,Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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24
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Abstract
Vasoactive intestinal peptide (VIP), a gut peptide hormone originally reported as a vasodilator in 1970, has multiple physiological and pathological effects on development, growth, and the control of neuronal, epithelial, and endocrine cell functions that in turn regulate ion secretion, nutrient absorption, gut motility, glycemic control, carcinogenesis, immune responses, and circadian rhythms. Genetic ablation of this peptide and its receptors in mice also provides new insights into the contribution of VIP towards physiological signaling and the pathogenesis of related diseases. Here, we discuss the impact of VIP on gastrointestinal function and diseases based on recent findings, also providing insight into its possible therapeutic application to diabetes, autoimmune diseases and cancer.
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Affiliation(s)
- Mari Iwasaki
- Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CA, USA
| | - Yasutada Akiba
- Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CA, USA.,Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Jonathan D Kaunitz
- Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CA, USA.,Departments of Medicine and Surgery, UCLA School of Medicine, Los Angeles, CA, USA
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25
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D'Andrea V, Marino I, Kaunitz JD. DDS-SIRC Collaboration: L'Inizio di una Bella Amicizia. Dig Dis Sci 2019; 64:2113. [PMID: 31190202 DOI: 10.1007/s10620-019-05680-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Affiliation(s)
- Vito D'Andrea
- Department of Surgical Sciences, La Sapienza University Hospital, 00128, Rome, RO, Italy
| | - Ignazio Marino
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Jonathan D Kaunitz
- West Los Angeles VA Medical Center and Departments of Medicine and Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90073, USA.
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26
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Abstract
PURPOSE OF REVIEW Short-chain fatty acids (SCFAs), the main bacterial fermentation products in the hindgut of hindgut fermenters, are also present in the foregut lumen. We discuss the impact of SCFAs in the duodenal defense mechanisms and in the gastrointestinal (GI) pathogenesis. RECENT FINDINGS Luminal SCFAs augment the duodenal mucosal defenses via release of serotonin (5-HT) and glucagon-like peptide-2 (GLP-2) from enteroendocrine cells. Released GLP-2 protects the small intestinal mucosa from nonsteroidal anti-inflammatory drug-induced enteropathy. SCFAs are also rapidly absorbed via SCFA transporters and interact with afferent and myenteric nerves. Excessive SCFA signals with 5-HT3 receptor overactivation may be implicated in the pathogenesis of irritable bowel syndrome symptoms. SCFA production exhibits diurnal rhythms with host physiological responses, suggesting that oral SCFA treatment may adjust the GI clocks. SCFAs are not only a source of energy but also signaling molecules for the local regulation of the GI tract and systemic regulation via release of gut hormones. Targeting SCFA signals may be a novel therapeutic for GI diseases and metabolic syndrome.
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Affiliation(s)
- Mari Iwasaki
- West Los Angeles VAMC, 11301 Wilshire Blvd., Los Angeles, CA, 90073, USA
| | - Yasutada Akiba
- West Los Angeles VAMC, 11301 Wilshire Blvd., Los Angeles, CA, 90073, USA
- Department of Medicine, The David Geffen School of Medicine, University of California, Los Angeles, CA, 90073, USA
| | - Jonathan D Kaunitz
- West Los Angeles VAMC, 11301 Wilshire Blvd., Los Angeles, CA, 90073, USA.
- Department of Medicine, The David Geffen School of Medicine, University of California, Los Angeles, CA, 90073, USA.
- Department of Surgery, The David Geffen School of Medicine, University of California, Los Angeles, CA, 90073, USA.
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27
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Bhattarai Y, Williams BB, Battaglioli EJ, Whitaker WR, Till L, Grover M, Linden DR, Akiba Y, Kandimalla KK, Zachos NC, Kaunitz JD, Sonnenburg JL, Fischbach MA, Farrugia G, Kashyap PC. Gut Microbiota-Produced Tryptamine Activates an Epithelial G-Protein-Coupled Receptor to Increase Colonic Secretion. Cell Host Microbe 2019; 23:775-785.e5. [PMID: 29902441 DOI: 10.1016/j.chom.2018.05.004] [Citation(s) in RCA: 222] [Impact Index Per Article: 44.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 03/28/2018] [Accepted: 05/09/2018] [Indexed: 02/06/2023]
Abstract
Tryptamine, a tryptophan-derived monoamine similar to 5-hydroxytryptamine (5-HT), is produced by gut bacteria and is abundant in human and rodent feces. However, the physiologic effect of tryptamine in the gastrointestinal (GI) tract remains unknown. Here, we show that the biological effects of tryptamine are mediated through the 5-HT4 receptor (5-HT4R), a G-protein-coupled receptor (GPCR) uniquely expressed in the colonic epithelium. Tryptamine increases both ionic flux across the colonic epithelium and fluid secretion in colonoids from germ-free (GF) and humanized (ex-GF colonized with human stool) mice, consistent with increased intestinal secretion. The secretory effect of tryptamine is dependent on 5-HT4R activation and is blocked by 5-HT4R antagonist and absent in 5-HT4R-/- mice. GF mice colonized by Bacteroides thetaiotaomicron engineered to produce tryptamine exhibit accelerated GI transit. Our study demonstrates an aspect of host physiology under control of a bacterial metabolite that can be exploited as a therapeutic modality. VIDEO ABSTRACT.
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Affiliation(s)
- Yogesh Bhattarai
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905, USA
| | - Brianna B Williams
- Department of Bioengineering and ChEM-H, Stanford University, Stanford, CA 94305, USA
| | - Eric J Battaglioli
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905, USA
| | - Weston R Whitaker
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94304, USA
| | - Lisa Till
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Madhusudan Grover
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905, USA; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - David R Linden
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Yasutada Akiba
- Department of Medicine, School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CA 90073, USA; Brentwood Biomedical Research Institute, Los Angeles, CA 90073, USA
| | - Karunya K Kandimalla
- Department of Pharmaceutics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Nicholas C Zachos
- Department of Medicine, Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jonathan D Kaunitz
- Department of Medicine, School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CA 90073, USA; Brentwood Biomedical Research Institute, Los Angeles, CA 90073, USA; Department of Surgery, School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Justin L Sonnenburg
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94304, USA
| | - Michael A Fischbach
- Department of Bioengineering and ChEM-H, Stanford University, Stanford, CA 94305, USA
| | - Gianrico Farrugia
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905, USA; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA; Division of Gastroenterology and Hepatology, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Purna C Kashyap
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905, USA; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA.
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28
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Affiliation(s)
- Jonathan D Kaunitz
- Departments of Medicine and Surgery, UCLA School of Medicine, Greater Los Angeles VA Healthcare System (GLAVAHCS), 11301 Wilshire Blvd, Bldg. 114/217E, Los Angeles, CA, 90073, USA.
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29
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Kaunitz JD, Akiba Y. A Tribute to Paul H. Guth, MD (1927-2017). Dig Dis Sci 2018; 63:807-810. [PMID: 29464586 DOI: 10.1007/s10620-018-4966-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Affiliation(s)
- Jonathan D Kaunitz
- Division of Gastroenterology, Department of Medicine, Greater Los Angeles VA Healthcare System, Bldg 114/217E, 11301 Wilshire Boulevard, Los Angeles, CA, 90073, USA. .,Department of Medicine, UCLA School of Medicine, Los Angeles, CA, USA. .,Department of Surgery, UCLA School of Medicine, Los Angeles, CA, USA.
| | - Yasutada Akiba
- Research Service, Greater Los Angeles VA Healthcare System, Los Angeles, CA, USA.,Department of Medicine, UCLA School of Medicine, Los Angeles, CA, USA
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30
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Takajo T, Akiba Y, Kaunitz JD. Teduglutide, the stable GLP‐2 analog inhibits lipid‐induced LPS transport into the portal vein and intestinal paracellular permeability after systemic inflammation. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.873.6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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31
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Bhattarai Y, Williams B, Battaglioli EJ, Grover M, Whitaker WR, Linden DR, Akiba Y, Kandimalla K, Zachos N, Kaunitz JD, Sonnenburg JL, Fischbach MA, Farrugia G, kashyap PC. Tryptamine Activates 5‐HT4 GPCR to Increase Secretion in the Mouse Proximal Colon. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.747.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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32
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Akiba Y, Takajo T, Kaunitz JD. Basolateral FFA2 of enterochromaffin cells contributes to 5‐HT release in rat and mouse duodenum. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.747.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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33
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Akiba Y, Kaunitz JD. [Duodenal mucosal defense mechanisms;Current update on 'Duodenology']. Nihon Shokakibyo Gakkai Zasshi 2018; 115:137-159. [PMID: 29459558 DOI: 10.11405/nisshoshi.115.137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Affiliation(s)
- Yasutada Akiba
- UCLA Depart of Medicine & West Los Angeles Veterans Affairs Medical Center
| | - Jonathan D Kaunitz
- UCLA Depart of Medicine & West Los Angeles Veterans Affairs Medical Center
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34
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Kaji I, Akiba Y, Furuyama T, Adelson DW, Iwamoto K, Watanabe M, Kuwahara A, Kaunitz JD. Free fatty acid receptor 3 activation suppresses neurogenic motility in rat proximal colon. Neurogastroenterol Motil 2018; 30:10.1111/nmo.13157. [PMID: 28714277 PMCID: PMC5739952 DOI: 10.1111/nmo.13157] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 06/14/2017] [Indexed: 02/06/2023]
Abstract
BACKGROUND Short-chain fatty acids (SCFA) are microbial fermentation products absorbed by the colon. We recently reported that activation of the SCFA receptor termed free fatty acid receptor 3 (FFA3), expressed on cholinergic nerves, suppresses nicotinic acetylcholine receptor (nAChR)-mediated transepithelial anion secretion. This study aimed to clarify how activation of neurally expressed FFA3 affects colonic motor function. METHODS FFA3-expressing myenteric neurons were identified by immunostaining; contractions of isolated circular muscle strips obtained from rat proximal colon were measured by isometric transducers. The effect of FFA3 agonists on defecation in vivo was examined in an exogenous serotonin-induced defecation model. KEY RESULTS FFA3 immunoreactivity was located in nitrergic and cholinergic neurons in the myenteric plexus. In isolated circular muscle strips without mucosa and submucosa, the addition of nicotine (10 μM) or serotonin transiently relaxed the muscle through nitrergic neurons, whereas high concentrations of nicotine (100 μM) induced large-amplitude contractions that were mediated by cholinergic neurons. Pretreatment with FFA3 agonists inhibited nicotine- or serotonin-induced motility changes but had no effect on bethanechol-induced direct muscle contractions. The Gi/o inhibitor pertussis toxin reversed the inhibitory effect of an FFA3 agonist AR420626 on nicotine-evoked contractions, suggesting that FFA3 activation suppresses nAChR-mediated neural activity in myenteric neurons, consistent with an FFA3-mediated antisecretory effect. In conscious rats, exogenous serotonin increased the volume of fecal output, compared with the vehicle- or AR420626-treated groups. Pretreatment with AR420626 significantly suppressed serotonin-induced fecal output. CONCLUSION AND INFERENCES FFA3 is a promising target for the treatment of neurogenic diarrheal disorders by suppressing nAChR-mediated neural pathways.
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Affiliation(s)
- Izumi Kaji
- Department of Medicine, University of California Los Angeles,Greater Los Angeles VA Healthcare System
| | - Yasutada Akiba
- Department of Medicine, University of California Los Angeles,Greater Los Angeles VA Healthcare System
| | - Takafumi Furuyama
- Neuroethology & Bioengineering, Graduate School of Life & Medical Sciences, Doshisha University,Japan Society for the Promotion of Science
| | | | - Kenichi Iwamoto
- Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka
| | - Masahiko Watanabe
- Department of Anatomy, Graduate School of Medicine, Hokkaido University
| | - Atsukazu Kuwahara
- Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka
| | - Jonathan D. Kaunitz
- Department of Medicine, University of California Los Angeles,Department of Surgery, University of California Los Angeles,Greater Los Angeles VA Healthcare System
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35
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Akiba Y, Maruta K, Narimatsu K, Said H, Kaji I, Kuri A, Iwamoto KI, Kuwahara A, Kaunitz JD. FFA2 activation combined with ulcerogenic COX inhibition induces duodenal mucosal injury via the 5-HT pathway in rats. Am J Physiol Gastrointest Liver Physiol 2017; 313:G117-G128. [PMID: 28526687 PMCID: PMC5582879 DOI: 10.1152/ajpgi.00041.2017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 05/04/2017] [Accepted: 05/13/2017] [Indexed: 01/31/2023]
Abstract
Serotonin (5-HT), predominantly synthesized and released by enterochromaffin cells, is implicated in gastrointestinal symptoms such as emesis, abdominal pain, and diarrhea. Because luminal short-chain fatty acids (SCFAs) release 5-HT from enterochromaffin cells, which express the SCFA receptor free fatty acid receptor 2 (FFA2) in rat duodenum, we examined the effects of the selective FFA2 agonist phenylacetamide-1 (PA1) on duodenal 5-HT release with consequent bicarbonate secretion [duodenal bicarbonate secretion (DBS)] and on indomethacin (IND)-induced enteropathy. Intestinal injury was induced by IND (10 mg/kg sc) with or without PA1. We measured DBS in vivo in a duodenal loop perfused with PA1 while measuring 5-HT released in the portal vein. Duodenal blood flow was measured by laser-Doppler flowmetry. IND induced small intestinal ulcers with duodenal sparing. PA1 given with IND (IND + PA1) dose dependently induced duodenal erosions. IND + PA1-induced duodenal lesions were inhibited by the FFA2 antagonist GLPG-0974, ondansetron, or omeprazole but not by RS-23597 or atropine. Luminal perfusion of PA1 augmented DBS accompanied by increased portal blood 5-HT concentrations with approximately eight times more release at 0.1 mM than at 1 µM, with the effects inhibited by coperfusion of GLPG-0974. Luminal PA1 at 1 µM increased, but at 0.1 mM diminished, duodenal blood flow. Cosuperfusion of PA1 (0.1 mM) decreased acid-induced hyperemia, further reduced by IND pretreatment but restored by ondansetron. These results suggest that, although FFA2 activation enhances duodenal mucosal defenses, FFA2 overactivation during ulcerogenic cyclooxygenase inhibition may increase the vulnerability of the duodenal mucosa to gastric acid via excessive 5-HT release and 5-HT3 receptor activation, implicated in foregut-related symptoms such as emesis and epigastralgia.NEW & NOTEWORTHY Luminal free fatty acid receptor 2 agonists stimulate enterochromaffin cells and release serotonin, which enhances mucosal defenses in rat duodenum. However, overdriving serotonin release with high luminal concentrations of free fatty acid 2 ligands such as short-chain fatty acids injures the mucosa by decreasing mucosal blood flow. These results are likely implicated in serotonin-related dyspeptic symptom generation because of small intestinal bacterial overgrowth, which is hypothesized to generate excess SCFAs in the foregut, overdriving serotonin release from enterochromaffin cells.
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Affiliation(s)
- Yasutada Akiba
- 1Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, California; ,2Department of Medicine, School of Medicine, University of California Los Angeles, Los Angeles, California; ,4Brentwood Biomedical Research Institute, Los Angeles, California; and
| | - Koji Maruta
- 2Department of Medicine, School of Medicine, University of California Los Angeles, Los Angeles, California;
| | - Kazuyuki Narimatsu
- 2Department of Medicine, School of Medicine, University of California Los Angeles, Los Angeles, California;
| | - Hyder Said
- 2Department of Medicine, School of Medicine, University of California Los Angeles, Los Angeles, California;
| | - Izumi Kaji
- 1Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, California; ,2Department of Medicine, School of Medicine, University of California Los Angeles, Los Angeles, California; ,4Brentwood Biomedical Research Institute, Los Angeles, California; and
| | - Ayaka Kuri
- 5University of Shizuoka Graduate School of Integrated Pharmaceutical and Nutritional Sciences, Shizuoka, Japan
| | - Ken-ichi Iwamoto
- 5University of Shizuoka Graduate School of Integrated Pharmaceutical and Nutritional Sciences, Shizuoka, Japan
| | - Atsukazu Kuwahara
- 5University of Shizuoka Graduate School of Integrated Pharmaceutical and Nutritional Sciences, Shizuoka, Japan
| | - Jonathan D. Kaunitz
- 1Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, California; ,2Department of Medicine, School of Medicine, University of California Los Angeles, Los Angeles, California; ,3Department of Surgery, School of Medicine, University of California Los Angeles, Los Angeles, California; ,4Brentwood Biomedical Research Institute, Los Angeles, California; and
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Said H, Akiba Y, Narimatsu K, Maruta K, Kuri A, Iwamoto KI, Kuwahara A, Kaunitz JD. FFA3 Activation Stimulates Duodenal Bicarbonate Secretion and Prevents NSAID-Induced Enteropathy via the GLP-2 Pathway in Rats. Dig Dis Sci 2017; 62:1944-1952. [PMID: 28523577 PMCID: PMC5511769 DOI: 10.1007/s10620-017-4600-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 04/29/2017] [Indexed: 02/08/2023]
Abstract
BACKGROUND Therapy with nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with enteropathy in humans and experimental animals, a cause of considerable morbidity. Unlike foregut NSAID-associated mucosal lesions, most treatments for this condition are of little efficacy. We propose that the endogenously released intestinotrophic hormone glucagon-like peptide-2 (GLP-2) prevents the development of NSAID-induced enteropathy. Since the short-chain fatty acid receptor FFA3 is expressed on enteroendocrine L cells and on enteric nerves in the gastrointestinal tract, we further hypothesized that activation of FFA3 on L cells protects the mucosa from injury via GLP-2 release with enhanced duodenal HCO3- secretion. We thus investigated the effects of synthetic selective FFA3 agonists with consequent GLP-2 release on NSAID-induced enteropathy. METHODS We measured duodenal HCO3- secretion in isoflurane-anesthetized rats in a duodenal loop perfused with the selective FFA3 agonists MQC or AR420626 (AR) while measuring released GLP-2 in the portal vein (PV). Intestinal injury was produced by indomethacin (IND, 10 mg/kg, sc) with or without MQC (1-10 mg/kg, ig) or AR (0.01-0.1 mg/kg, ig or ip) treatment. RESULTS Luminal perfusion with MQC or AR (0.1-10 µM) dose-dependently augmented duodenal HCO3- secretion accompanied by increased GLP-2 concentrations in the PV. The effect of FFA3 agonists was inhibited by co-perfusion of the selective FFA3 antagonist CF3-MQC (30 µM). AR-induced augmented HCO3- secretion was reduced by iv injection of the GLP-2 receptor antagonist GLP-2(3-33) (3 nmol/kg), or by pretreatment with the cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor CFTRinh-172 (1 mg/kg, ip). IND-induced small intestinal ulcers were dose-dependently inhibited by intragastric administration of MQC or AR. GLP-2(3-33) (1 mg/kg, ip) or CF3-MQC (1 mg/kg, ig) reversed AR-associated reduction in IND-induced enteropathy. In contrast, ip injection of AR had no effect on enteropathy. CONCLUSION These results suggest that luminal FFA3 activation enhances mucosal defenses and prevents NSAID-induced enteropathy via the GLP-2 pathway. The selective FFA3 agonist may be a potential therapeutic candidate for NSAID-induced enteropathy.
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Affiliation(s)
- Hyder Said
- College of Arts and Sciences, University of California, Los Angeles, CA, USA
| | - Yasutada Akiba
- Greater Los Angeles Veterans Affairs Healthcare System, 11301 Wilshire Boulevard, Bldg 115, Suite 217, Los Angeles, CA, 90073, USA
- Department of Medicine, University of California Los Angeles, School of Medicine, Los Angeles, CA, USA
- Brentwood Biomedical Research Institute, Los Angeles, CA, USA
| | - Kazuyuki Narimatsu
- Department of Medicine, University of California Los Angeles, School of Medicine, Los Angeles, CA, USA
| | - Koji Maruta
- Department of Medicine, University of California Los Angeles, School of Medicine, Los Angeles, CA, USA
| | - Ayaka Kuri
- Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan
| | - Ken-Ichi Iwamoto
- Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan
| | - Atsukazu Kuwahara
- Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan
| | - Jonathan D Kaunitz
- Greater Los Angeles Veterans Affairs Healthcare System, 11301 Wilshire Boulevard, Bldg 115, Suite 217, Los Angeles, CA, 90073, USA.
- Department of Medicine, University of California Los Angeles, School of Medicine, Los Angeles, CA, USA.
- Brentwood Biomedical Research Institute, Los Angeles, CA, USA.
- Department of Surgery, University of California Los Angeles, School of Medicine, Los Angeles, CA, USA.
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Affiliation(s)
- Jonathan D. Kaunitz
- Attending Physician, West Los Angeles VA Medical Center, Professor of Medicine and Surgery, UCLA School of Medicine Los Angeles, CA 90073
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Kaji I, Akiba Y, Kato I, Maruta K, Kuwahara A, Kaunitz JD. Xenin Augments Duodenal Anion Secretion via Activation of Afferent Neural Pathways. J Pharmacol Exp Ther 2017; 361:151-161. [PMID: 28115552 DOI: 10.1124/jpet.116.238485] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/18/2017] [Indexed: 12/19/2022] Open
Abstract
Xenin-25, a neurotensin (NT)-related anorexigenic gut hormone generated mostly in the duodenal mucosa, is believed to increase the rate of duodenal ion secretion, because xenin-induced diarrhea is not present after Roux-en-Y gastric bypass surgery. Because the local effects of xenin on duodenal ion secretion have remained uninvestigated, we thus examined the neural pathways underlying xenin-induced duodenal anion secretion. Intravenous infusion of xenin-8, a bioactive C-terminal fragment of xenin-25, dose dependently increased the rate of duodenal HCO3- secretion in perfused duodenal loops of anesthetized rats. Xenin was immunolocalized to a subset of enteroendocrine cells in the rat duodenum. The mRNA of the xenin/NT receptor 1 (NTS1) was predominantly expressed in the enteric plexus, nodose and dorsal root ganglia, and in the lamina propria rather than in the epithelium. The serosal application of xenin-8 or xenin-25 rapidly and transiently increased short-circuit current in Ussing-chambered mucosa-submucosa preparations in a concentration-dependent manner in the duodenum and jejunum, but less so in the ileum and colon. The selective antagonist for NTS1, substance P (SP) receptor (NK1), or 5-hydroxytryptamine (5-HT)3, but not NTS2, inhibited the responses to xenin. Xenin-evoked Cl- secretion was reduced by tetrodotoxin (TTX) or capsaicin-pretreatment, and abolished by the inhibitor of TTX-resistant sodium channel Nav1.8 in combination with TTX, suggesting that peripheral xenin augments duodenal HCO3- and Cl- secretion through NTS1 activation on intrinsic and extrinsic afferent nerves, followed by release of SP and 5-HT. Afferent nerve activation by postprandial, peripherally released xenin may account for its secretory effects in the duodenum.
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Affiliation(s)
- Izumi Kaji
- Greater Los Angeles Veterans Affairs Healthcare System Los Angeles, California (I.K., Y.A., J.D.K.); Departments of Medicine (I.K., Y.A., K.M., J.D.K.) and Surgery (J.D.K.), David Geffen School of Medicine at UCLA, Los Angeles, California; Department of Medical Biochemistry, Kobe Pharmaceutical University, Kobe, Kobe, Japan (I.K.); and Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Japan (A.K.)
| | - Yasutada Akiba
- Greater Los Angeles Veterans Affairs Healthcare System Los Angeles, California (I.K., Y.A., J.D.K.); Departments of Medicine (I.K., Y.A., K.M., J.D.K.) and Surgery (J.D.K.), David Geffen School of Medicine at UCLA, Los Angeles, California; Department of Medical Biochemistry, Kobe Pharmaceutical University, Kobe, Kobe, Japan (I.K.); and Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Japan (A.K.)
| | - Ikuo Kato
- Greater Los Angeles Veterans Affairs Healthcare System Los Angeles, California (I.K., Y.A., J.D.K.); Departments of Medicine (I.K., Y.A., K.M., J.D.K.) and Surgery (J.D.K.), David Geffen School of Medicine at UCLA, Los Angeles, California; Department of Medical Biochemistry, Kobe Pharmaceutical University, Kobe, Kobe, Japan (I.K.); and Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Japan (A.K.)
| | - Koji Maruta
- Greater Los Angeles Veterans Affairs Healthcare System Los Angeles, California (I.K., Y.A., J.D.K.); Departments of Medicine (I.K., Y.A., K.M., J.D.K.) and Surgery (J.D.K.), David Geffen School of Medicine at UCLA, Los Angeles, California; Department of Medical Biochemistry, Kobe Pharmaceutical University, Kobe, Kobe, Japan (I.K.); and Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Japan (A.K.)
| | - Atsukazu Kuwahara
- Greater Los Angeles Veterans Affairs Healthcare System Los Angeles, California (I.K., Y.A., J.D.K.); Departments of Medicine (I.K., Y.A., K.M., J.D.K.) and Surgery (J.D.K.), David Geffen School of Medicine at UCLA, Los Angeles, California; Department of Medical Biochemistry, Kobe Pharmaceutical University, Kobe, Kobe, Japan (I.K.); and Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Japan (A.K.)
| | - Jonathan D Kaunitz
- Greater Los Angeles Veterans Affairs Healthcare System Los Angeles, California (I.K., Y.A., J.D.K.); Departments of Medicine (I.K., Y.A., K.M., J.D.K.) and Surgery (J.D.K.), David Geffen School of Medicine at UCLA, Los Angeles, California; Department of Medical Biochemistry, Kobe Pharmaceutical University, Kobe, Kobe, Japan (I.K.); and Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Japan (A.K.)
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Abstract
The ability of humans to sense chemical signals in ingested substances is implicit in the ability to detect the five basic tastes; sweet, sour, bitter, salty, and umami. Of these, sweet, bitter, and umami tastes are detected by lingual G-protein-coupled receptors (GPCRs). Recently, these receptors were also localized to the gut mucosa. In this review, we will emphasize recent advances in the understanding of the mechanisms and consequences of foregut luminal chemosensing, with special emphasis on cell surface GPCRs such as the sweet and proteinaceous taste receptors (TASRs), short- and long-chain fatty acid (FA) receptors, and bile acid receptors. The majority of these luminal chemosensors are expressed on enteroendocrine cells (EECs), which are specialized endocrine cells in the intestine and pancreas that release gut hormones with ligand activation. These gut hormones are responsible for a wide variety of physiologic and homeostatic mechanisms, including glycemic control, appetite stimulation and suppression, regulation of gastric emptying, and trophic effects on the intestinal epithelium. Released from the EECs, the gut peptides have paracrine, autocrine, and endocrine effects. Additionally, EECs have unique direct connections to the enteric nervous system enabling precise transmission of sensory data to and communication with the central nervous system. We will also describe how gut sensors are implicated in gut hormone release, followed by examples of how altered gut chemosensing has been implicated in pathological conditions such as metabolic diseases including diabetes and obesity, functional dyspepsia, helminthic infections, colitis, gastric bypass surgery, and gastric inflammation and cancer.
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Affiliation(s)
| | - Jonathan D Kaunitz
- Medical Service, West Los Angeles Veterans Affairs Medical Center, Los Angeles, CA, USA; Departments of Medicine and Surgery, UCLA, Los Angeles, CA, USA
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Kaunitz JD. DDS Elementary Style: A Brief Guide for Authors. Dig Dis Sci 2016; 61:2147-2150. [PMID: 27312030 DOI: 10.1007/s10620-016-4223-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Affiliation(s)
- Jonathan D Kaunitz
- Departments of Medicine and Surgery, Greater Los Angeles VA Healthcare System, UCLA School of Medicine, Los Angeles, CA, 90073, USA.
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Affiliation(s)
- Yasutada Akiba
- Greater Los Angeles VA Healthcare System, UCLA School of Medicine, Los Angeles, California; and
| | - Jonathan D Kaunitz
- Greater Los Angeles VA Healthcare System, UCLA School of Medicine, Los Angeles, California; and
| | - Marshall H Montrose
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio
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Kaji I, Akiba Y, Konno K, Watanabe M, Kimura S, Iwanaga T, Kuri A, Iwamoto KI, Kuwahara A, Kaunitz JD. Neural FFA3 activation inversely regulates anion secretion evoked by nicotinic ACh receptor activation in rat proximal colon. J Physiol 2016; 594:3339-52. [PMID: 26854275 DOI: 10.1113/jp271441] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 01/19/2016] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS Luminal short-chain fatty acids (SCFAs) influence gut physiological function via SCFA receptors and transporters. The contribution of an SCFA receptor, free fatty acid receptor (FFA)3, to the enteric nervous system is unknown. FFA3 is expressed in enteric cholinergic neurons. Activation of neural FFA3 suppresses Cl(-) secretion induced by nicotinic ACh receptor activation via a Gi/o pathway. Neural FFA3 may have an anti-secretory function by modulating cholinergic neural reflexes in the enteric nervous system. ABSTRACT The proximal colonic mucosa is constantly exposed to high concentrations of microbially-produced short-chain fatty acids (SCFAs). Although luminal SCFAs evoke electrogenic anion secretion and smooth muscle contractility via neural and non-neural cholinergic pathways in the colon, the involvement of the SCFA receptor free fatty acid receptor (FFA)3, one of the free fatty acid receptor family members, has not been clarified. We investigated the contribution of FFA3 to cholinergic-mediated secretory responses in rat proximal colon. FFA3 was immunolocalized to enteroendocrine cells and to the enteric neural plexuses. Most FFA3-immunoreactive nerve fibres and nerve endings were cholinergic, colocalized with protein gene product (PGP)9.5, the vesicular ACh transporter, and the high-affinity choline transporter CHT1. In Ussing chambered mucosa-submucosa preparations (including the submucosal plexus) of rat proximal colon, carbachol (CCh)-induced Cl(-) secretion was decreased by TTX, hexamethonium, and the serosal FFA3 agonists acetate or propionate, although not by an inactive analogue 3-chloropropionate. Serosal application of a selective FFA3 agonist (N-[2-methylphenyl]-[4-furan-3-yl]-2-methyl-5-oxo-1,4,5,6,7,8-hexahydro-quinoline-3-carboxamide; MQC) dose-dependently suppressed the response to CCh but not to forskolin, with an IC50 of 13 μm. Pretreatment with MQC inhibited nicotine-evoked but not bethanechol-evoked secretion. The inhibitory effect of MQC was reversed by pretreatment with pertussis toxin, indicating that FFA3 acts via the Gi/o pathway. Luminal propionate induced Cl(-) secretion via the cholinergic pathway, which was reduced by MQC, as well as by TTX, hexamethonium or removal of the submucosal plexus. These results suggest that the SCFA-FFA3 pathway has a novel anti-secretory function in that it inhibits cholinergic neural reflexes in the enteric nervous system.
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Affiliation(s)
- Izumi Kaji
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Brentwood Biomedical Research Institution, Los Angeles, CA, USA
| | - Yasutada Akiba
- Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CA, USA.,Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Brentwood Biomedical Research Institution, Los Angeles, CA, USA
| | - Kohtarou Konno
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Shunsuke Kimura
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Toshihiko Iwanaga
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Ayaka Kuri
- University of Shizuoka Graduate School of Integrated Pharmaceutical and Nutritional Sciences, Shizuoka, Japan
| | - Ken-Ichi Iwamoto
- University of Shizuoka Graduate School of Integrated Pharmaceutical and Nutritional Sciences, Shizuoka, Japan
| | - Atsukazu Kuwahara
- University of Shizuoka Graduate School of Integrated Pharmaceutical and Nutritional Sciences, Shizuoka, Japan
| | - Jonathan D Kaunitz
- Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CA, USA.,Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Brentwood Biomedical Research Institution, Los Angeles, CA, USA
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Akiba Y, Inoue T, Kaji I, Higashiyama M, Narimatsu K, Iwamoto KI, Watanabe M, Guth PH, Engel E, Kuwahara A, Kaunitz JD. Short-chain fatty acid sensing in rat duodenum. J Physiol 2016; 593:585-99. [PMID: 25433076 DOI: 10.1113/jphysiol.2014.280792] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 11/06/2014] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Luminal lipid in the duodenum modulates gastroduodenal functions via the release of gut hormones and mediators such as cholecystokinin and 5-HT. The effects of luminal short-chain fatty acids (SCFAs) in the foregut are unknown. Free fatty acid receptors (FFARs) for long-chain fatty acids (LCFAs) and SCFAs are expressed in enteroendocrine cells. SCFA receptors, termed FFA2 and FFA3, are expressed in duodenal enterochromaffin cells and L cells, respectively. Activation of LCFA receptor (FFA1) and presumed FFA3 stimulates duodenal HCO3(-) secretion via a glucagon-like peptide (GLP)-2 pathway, whereas FFA2 activation induces HCO3(-) secretion via muscarinic and 5-HT4 receptor activation. The presence of SCFA sensing in the duodenum with GLP-2 and 5-HT signals further supports the hypothesis that luminal SCFA in the foregut may contribute towards the generation of functional symptoms. ABSTRACT Intraduodenal fatty acids (FA) and bacterial overgrowth, which generate short-chain FAs (SCFAs), have been implicated in the generation of functional dyspepsia symptoms. We studied the mechanisms by which luminal SCFA perfusion affects duodenal HCO3(-) secretion (DBS), a measure of mucosal neurohumoral activation. Free fatty acid receptor (FFAR) 1 (FFA1), which binds long-chain FA (LCFA), and SCFA receptors FFA2 and FFA3 were immunolocalised to duodenal enteroendocrine cells. FFA3 colocalised with glucagon-like peptide (GLP)-1, whereas FFA2 colocalised with 5-HT. Luminal perfusion of the SCFA acetate or propionate increased DBS, enhanced by dipeptidyl peptidase-IV (DPPIV) inhibition, at the same time as increasing GLP-2 portal blood concentrations. Acetate-induced DBS was partially inhibited by monocarboxylate/HCO3(-) exchanger inhibition without affecting GLP-2 release, implicating acetate absorption in the partial mediation of DBS. A selective FFA2 agonist dose-dependently increased DBS, unaffected by DPPIV inhibition or by cholecystokinin or 5-HT3 receptor antagonists, but was inhibited by atropine and a 5-HT4 antagonist. By contrast, a selective FFA1 agonist increased DBS accompanied by GLP-2 release, enhanced by DPPIV inhibition and inhibited by a GLP-2 receptor antagonist. Activation of FFA1 by LCFA and presumably FFA3 by SCFA increased DBS via GLP-2 release, whereas FFA2 activation stimulated DBS via muscarinic and 5-HT4 receptor activation. SCFA/HCO3(-) exchange also appears to be present in the duodenum. The presence of duodenal fatty acid sensing receptors that signal hormone release and possibly signal neural activation may be implicated in the pathogenesis of functional dyspepsia.
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Affiliation(s)
- Yasutada Akiba
- Greater Los Angeles Veterans Affairs Healthcare System, 11301 Wilshire Boulevard, Los Angeles, CA, 90073, USA; Department of Medicine, University of California, Los Angeles, CA, 90095, USA; Brentwood Biomedical Research Institute, 11301 Wilshire Blvd, Los Angeles, CA, 90073, USA
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Watanabe C, Komoto S, Tomita K, Hokari R, Tanaka M, Hirata I, Hibi T, Kaunitz JD, Miura S. Endoscopic and clinical evaluation of treatment and prognosis of Cronkhite-Canada syndrome: a Japanese nationwide survey. J Gastroenterol 2016; 51. [PMID: 26216651 PMCID: PMC4805704 DOI: 10.1007/s00535-015-1107-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND First reported in 1955, Cronkhite-Canada syndrome (CCS), a rare syndrome characterized by ectodermal abnormalities and inflammatory changes of the gastrointestinal tract mucosa, has been associated with a poor prognosis and life-threatening malignant complications. In a large population survey, we endeavored to characterize the course and treatment outcome of CCS through clinical and endoscopic assessment, and to explore its optimal treatment and surveillance strategy. METHODS A retrospective analysis of 210 patients with CCS was conducted via a questionnaire-based nationwide survey of 983 teaching hospitals located throughout Japan. We assessed clinical features, endoscopic findings, treatments used, and short- and long-term outcomes. RESULTS The average age at diagnosis was 63.5 years. In all cases, upper or lower gastrointestinal tract polyposis was confirmed, accompanied by characteristic ectodermal abnormalities. Of the treatments used, oral corticosteroids (30-49 mg/day) were the most effective treatment for active disease, with adjunctive nutritional support considered beneficial. With corticosteroid treatment, abdominal symptoms were relieved within a few months, whereas polyp regression often required more than 6 months. Maintenance of endoscopic remission with or without steroids for 3 years significantly lowered the development of CCS-related cancer, compared with relapsers or nonresponders, underscoring the importance of sustained endoscopic remission for cancer prevention. CONCLUSIONS The prognosis of CCS has greatly improved through the use of improved medical treatment. Although CCS continues to be relentlessly progressive, carrying a high cancer risk, a sufficient dose and duration of corticosteroid therapy accompanied by nutritional support and periodic endoscopic surveillance appears to improve its natural history.
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Affiliation(s)
- Chikako Watanabe
- />Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513 Japan
| | - Shunsuke Komoto
- />Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513 Japan
| | - Kengo Tomita
- />Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513 Japan
| | - Ryota Hokari
- />Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513 Japan
| | - Masanori Tanaka
- />Department of Pathology and Laboratory Medicine, Hirosaki City Hospital, Aomori, Japan
| | - Ichiro Hirata
- />Department of Gastroenterology, Fujita Health University, Aichi, Japan
| | - Toshifumi Hibi
- />Center for Advanced IBD Research and Treatment, Kitasato Institute Hospital, Tokyo, Japan
| | - Jonathan D. Kaunitz
- />Greater Los Angeles VA Medical Center and Department of Medicine and Department of Surgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA USA
| | - Soichiro Miura
- />Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513 Japan
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Kaji I, Akiba Y, Said H, Narimatsu K, Kaunitz JD. Luminal 5-HT stimulates colonic bicarbonate secretion in rats. Br J Pharmacol 2015; 172:4655-70. [PMID: 26061462 DOI: 10.1111/bph.13216] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 04/16/2015] [Accepted: 05/09/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE The bioactive monoamine 5-HT, implicated in the pathogenesis of functional gastrointestinal disorders, is abundantly synthesized and stored in rat proximal colonic mucosa and released to the gut lumen and subepithelial space. Despite much data regarding its expression and function, the effects of luminal 5-HT on colonic anion secretion have not been fully investigated. EXPERIMENTAL APPROACH We measured short-circuit current (Isc ) as an indicator of ion transport in mucosa-submucosa or mucosa-only preparations of rat proximal colon. Total CO2 output was measured in vitro and in vivo. Immunohistochemistry was performed to investigate the localization of 5-HT4 , NOS1 and NOS2. KEY RESULTS Luminal 5-HT gradually increased the amplitude and sustained the elevation of Isc . Luminal 5-HT-evoked ΔIsc was acetazolamide sensitive and HCO3 (-) dependent, consistent with cytosolic carbonic anhydrase-dependent electrogenic HCO3 (-) secretion, while not affected by tetrodotoxin (TTX), atropine or indomethacin. Pretreatment with the selective 5-HT4 antagonist GR113808, but not antagonists for 5-HT3 , 5-HT6 or 5-HT7 , inhibited luminal 5-HT-evoked ΔIsc . Furthermore, luminal cisapride and tegaserod increased Isc to the same extent as did 5-HT in the presence of indomethacin and TTX. Removal of the submucosa or pretreatment with NOS inhibitors enhanced luminal 5-HT-evoked ΔIsc , suggesting that NO synthesized in the submucosa suppresses mucosal anion secretion. NOS1 and NOS2 were immunostained in the submucosal neurons and glial cells respectively. Luminal 5-HT-evoked HCO3 (-) secretion was confirmed in vivo, inhibited by co-perfusion of GR113808, but not by ondansetron. CONCLUSIONS AND IMPLICATIONS A novel apical 5-HT4 -mediated HCO3 (-) secretory pathway and an NO-dependent inhibitory mechanism are present in the proximal colon. Luminal 5-HT-evoked HCO3 (-) secretion may be important for the maintenance of mucosal integrity by regulating luminal pH.
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Affiliation(s)
- I Kaji
- Department of Medicine, University of California, Los Angeles, CA, USA.,Brentwood Biomedical Research Institute, Los Angeles, CA, USA
| | - Y Akiba
- Department of Medicine, University of California, Los Angeles, CA, USA.,Brentwood Biomedical Research Institute, Los Angeles, CA, USA.,Greater Los Angeles Veterans Affairs Healthcare System, CA, USA
| | - H Said
- College of Letters and Sciences, University of California, Los Angeles, CA, USA
| | - K Narimatsu
- Department of Medicine, University of California, Los Angeles, CA, USA
| | - J D Kaunitz
- Department of Medicine, University of California, Los Angeles, CA, USA.,Department of Surgery, School of Medicine, University of California, Los Angeles, CA, USA.,Brentwood Biomedical Research Institute, Los Angeles, CA, USA.,Greater Los Angeles Veterans Affairs Healthcare System, CA, USA
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Akiba Y, Kaunitz JD, Million M. Peripheral corticotropin-releasing factor receptor type 2 activation increases colonic blood flow through nitric oxide pathway in rats. Dig Dis Sci 2015; 60:858-67. [PMID: 25701320 PMCID: PMC4501405 DOI: 10.1007/s10620-015-3579-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 02/04/2015] [Indexed: 12/30/2022]
Abstract
BACKGROUND Corticotropin-releasing factor (CRF) peptides exert profound effects on the secretomotor function of the gastrointestinal tract. Nevertheless, despite the presence of CRF peptides and receptors in colonic tissue, their influence on colonic blood flow (CBF) is unknown. AIM To determine the effect and mechanism of members of the CRF peptide family on CBF in isoflurane-anesthetized rats. METHODS Proximal CBF was measured with laser-Doppler flowmetry simultaneously with mean arterial blood pressure (MABP) measurement. Rats were injected with intravenous human/rat CRF (CRF1 > CRF2 affinity), mouse urocortin 2 (mUcn2, selective CRF2 agonist), or sauvagine (SVG, CRF2 > CRF1 affinity) at 1-30 µg/kg. The nitric oxide (NO) synthase inhibitor, L-NAME (3 mg/kg, iv), the cyclooxygenase inhibitor, indomethacin (Indo, 5 mg/kg, ip), or selective CRF2 antagonist, astressin2-B (Ast2B, 50 µg/kg, iv) was given before SVG injection (10 µg/kg, iv). RESULTS SVG and mUcn2 dose-dependently increased CBF while decreasing MABP and colonic vascular resistance (CVR). CRF had no effect on CBF, but increased CVR. The hyperemic effect of SVG was inhibited by L-NAME but not by Indo, whereas hypotension was partially reduced by L-NAME. Sensory denervation had no effect on SVG-induced changes. Ast2B inhibited SVG-induced hyperemia and decreased CVR, and partially reduced the hypotension. CONCLUSIONS Peripheral CRF2 activation induces colonic hyperemia through NO synthesis, without involving prostaglandin synthesis or sensory nerve activation, suggesting a direct action on the endothelium and myenteric neurons. Members of the CRF peptide family may protect the colonic mucosa via the activation of the CRF2 receptor.
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Affiliation(s)
- Yasutada Akiba
- CURE: Digestive Diseases Research Center; Oppenheimer Family Center for Neurobiology of Stress, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA,
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Affiliation(s)
- Dennis J Ahnen
- University of Colorado School of Medicine, Denver, CO, USA,
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49
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Sakanaka T, Inoue T, Yorifuji N, Iguchi M, Fujiwara K, Narabayashi K, Kakimoto K, Nouda S, Okada T, Kuramoto T, Ishida K, Abe Y, Takeuchi T, Umegaki E, Akiba Y, Kaunitz JD, Higuchi K. The effects of a TGR5 agonist and a dipeptidyl peptidase IV inhibitor on dextran sulfate sodium-induced colitis in mice. J Gastroenterol Hepatol 2015; 30 Suppl 1:60-5. [PMID: 25827806 PMCID: PMC4874188 DOI: 10.1111/jgh.12740] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/08/2014] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIM Luminal nutrients stimulate enteroendocrine L cells to release gut hormones, including intestinotrophic glucagon-like peptide-2 (GLP-2). Because L cells express the bile acid receptor TGR5 and dipeptidyl peptidase-IV (DPPIV) rapidly degrades GLPs, we hypothesized that luminal TGR5 activation may attenuate intestinal injury via GLP-2 release, which is enhanced by DPPIV inhibition. METHODS Intestinal injury was induced in mice by administration of dextran sulfate sodium (DSS) in drinking water (free access to water containing 5% DSS for 7 days). The selective TGR5 agonist betulinic acid (BTA) and the DPPIV inhibitor sitagliptin phosphate monohydrate (STG) were administered orally for 7 days. Male C57BL/6 mice (6-7 weeks old) were divided into five groups: normal control group, disease control group, BTA low group (drinking water containing 15 mg/L BTA), BTA high group (50 mg/L BTA), and BTA high + STG (3 mg/kg, i.g.) group. RESULTS The selective TGR5 agonist BTA dose-dependently suppressed disease activity index and mRNA expression of the pro-inflammatory cytokines interleukin (IL)-1β, IL-6, and tumor necrosis factor-α in the colon. Nevertheless, STG administration had little additive effect on BTA-induced protection. Fibroblast activation protein mRNA expression, but not expression of other DPP family members, was increased in the colon of DSS-treated mice with increased mucosal DPPIV. Co-administration of the selective GLP-2 antagonist GLP-2 (3-33) reversed the effect of BTA. CONCLUSION The selective TGR5 agonist BTA ameliorated DSS-induced colitis in mice via the GLP-2 pathway with no effect of DPPIV inhibition, suggesting that other DPP enzymatic activity is involved in GLP-2 degradation.
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Affiliation(s)
- Taisuke Sakanaka
- Second Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Takuya Inoue
- Second Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Naoki Yorifuji
- Second Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Munetaka Iguchi
- Second Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Kaori Fujiwara
- Second Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Ken Narabayashi
- Second Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Kazuki Kakimoto
- Second Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Sadaharu Nouda
- Second Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Toshihiko Okada
- Second Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Takanori Kuramoto
- Second Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Kumi Ishida
- Second Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Yosuke Abe
- Second Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Toshihisa Takeuchi
- Second Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Eiji Umegaki
- Second Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
| | - Yasutada Akiba
- Greater Los Angeles Veterans Affairs Healthcare System, University of California, Los Angeles, California, USA
| | - Jonathan D. Kaunitz
- Greater Los Angeles Veterans Affairs Healthcare System, University of California, Los Angeles, California, USA
| | - Kazuhide Higuchi
- Second Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
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Abstract
Bacterial or ingested food-derived short-chain fatty acids (SCFAs) are present in the duodenal lumen. Acetate, the most abundant SCFA in the foregut lumen, is absorbed immediately after ingestion, although the mechanism by which this absorption occurs is not fully understood. We investigated the distribution and function of candidate SCFA transporters in rat duodenum. The Na(+)-coupled monocarboxylate transporter-1 (SMCT1) was localized to the brush border, whereas the pH-dependent monocarboxylate transporter (MCT) 1 and MCT4 were localized to the duodenocyte basolateral membrane. In Ussing chambered duodenal mucosa, luminal acetate dose-dependently increased short-circuit current (Isc) in the presence of serosal bumetanide and indomethacin by a luminal Na(+)-dependent, ouabain-sensitive mechanism. The Isc response was inhibited dose-dependently by the SMCT1 nonsubstrate inhibitor ibuprofen, consistent with net electrogenic absorption of acetate via SMCT1. Other SCFAs and lactate also increased Isc. Furthermore, duodenal loop perfusion of acetate increased portal venous acetate concentration, inhibited by coperfusion of ibuprofen or a MCT inhibitor. Luminal acetate perfusion increased duodenal HCO3 (-) secretion via capsaicin-sensitive afferent nerve activation and cyclooxygenase activity, consistent with absorption-mediated HCO3 (-) secretion. These results suggest that absorption of luminal SCFA via SMCT1 and MCTs increases duodenal HCO3 (-) secretion. In addition to SCFA sensing via free fatty acid receptors, the presence of rapid duodenal SCFA absorption may be important for the suppression of luminal bacterial colonization and implicated in the generation of functional dyspepsia due to bacterial overgrowth.
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Affiliation(s)
- Izumi Kaji
- 2Department of Medicine, School of Medicine, University of California, Los Angeles, Los Angeles, California; ,5Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan; and ,6Brentwood Biomedical Research Institute, Los Angeles, California
| | - Toshihiko Iwanaga
- 5Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan; and
| | - Masahiko Watanabe
- 5Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan; and
| | - Paul H. Guth
- 1Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, California; ,2Department of Medicine, School of Medicine, University of California, Los Angeles, Los Angeles, California;
| | - Eli Engel
- 4Department of Biomathematics, School of Medicine, University of California, Los Angeles, Los Angeles, California;
| | - Jonathan D. Kaunitz
- 1Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, California; ,2Department of Medicine, School of Medicine, University of California, Los Angeles, Los Angeles, California; ,3Department of Surgery, School of Medicine, University of California, Los Angeles, Los Angeles, California; ,6Brentwood Biomedical Research Institute, Los Angeles, California
| | - Yasutada Akiba
- 1Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, California; ,2Department of Medicine, School of Medicine, University of California, Los Angeles, Los Angeles, California; ,6Brentwood Biomedical Research Institute, Los Angeles, California
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