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Kumar A, Priyamvada S, Soni V, Anbazhagan AN, Gujral T, Gill RK, Alrefai WA, Dudeja PK, Saksena S. Angiotensin II inhibits P-glycoprotein in intestinal epithelial cells. Acta Physiol (Oxf) 2020; 228:e13332. [PMID: 31177627 PMCID: PMC6899205 DOI: 10.1111/apha.13332] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 05/24/2019] [Accepted: 06/04/2019] [Indexed: 01/15/2023]
Abstract
AIM P-glycoprotein (Pgp/MDR1) plays a major role in intestinal homeostasis. Decrease in Pgp function and expression has been implicated in the pathogenesis of IBD. However, inhibitory mechanisms involved in the decrease of Pgp in inflammation are not fully understood. Angiotensin II (Ang II), a peptide hormone predominantly expressed in the epithelial cells of the crypt-villus junction of the intestine, has been shown to exert pro-inflammatory effects in the gut. It is increased in IBD patients and animals with experimental colitis. Whether Ang II directly influences Pgp is not known. METHODS Pgp activity was measured as verapamil-sensitive 3 H-digoxin flux. Pgp surface expression and exocytosis were measured by cell surface biotinylation studies. Signalling pathways were elucidated by Western blot analysis and pharmacological approaches. RESULTS Ang II (10 nM) significantly inhibited Pgp activity at 60 minutes. Ang II-mediated effects on Pgp function were receptor-mediated as the Ang II receptor 1 (ATR1) antagonist, losartan, blocked Pgp inhibition. Ang II effects on Pgp activity appeared to be mediated via PI3 kinase, p38 MAPK and Akt signalling. Ang II-mediated inhibition of Pgp activity was associated with a decrease in the surface membrane expression of Pgp protein via decreased exocytosis and was found to be dependent on the Akt pathway. Short-term treatment of Ang II (2 mg/kg b.wt., 2 hours) to mice also decreased the membrane expression of Pgp protein levels in ileum and colon. CONCLUSION Our findings provide novel insights into the role of Ang II and ATR1 in decreasing Pgp expression in intestinal inflammation.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- Angiotensin II/administration & dosage
- Angiotensin II/pharmacology
- Animals
- Caco-2 Cells
- Dose-Response Relationship, Drug
- Epithelial Cells/drug effects
- Epithelial Cells/metabolism
- Gene Expression Regulation/drug effects
- Humans
- Intestinal Mucosa/cytology
- Mice
- Phosphatidylinositol 3-Kinases/genetics
- Phosphatidylinositol 3-Kinases/metabolism
- Proto-Oncogene Proteins c-akt/genetics
- Proto-Oncogene Proteins c-akt/metabolism
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/metabolism
- Receptor, Angiotensin, Type 2/genetics
- Receptor, Angiotensin, Type 2/metabolism
- p38 Mitogen-Activated Protein Kinases/genetics
- p38 Mitogen-Activated Protein Kinases/metabolism
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Affiliation(s)
- Anoop Kumar
- Division of Gastroenterology & Hepatology, Dept. of Medicine, University of Illinois at Chicago
| | - Shubha Priyamvada
- Division of Gastroenterology & Hepatology, Dept. of Medicine, University of Illinois at Chicago
| | - Vikas Soni
- Division of Gastroenterology & Hepatology, Dept. of Medicine, University of Illinois at Chicago
| | - Arivarasu N. Anbazhagan
- Division of Gastroenterology & Hepatology, Dept. of Medicine, University of Illinois at Chicago
| | - Tarunmeet Gujral
- Division of Gastroenterology & Hepatology, Dept. of Medicine, University of Illinois at Chicago
| | - Ravinder K Gill
- Division of Gastroenterology & Hepatology, Dept. of Medicine, University of Illinois at Chicago
| | - Waddah A. Alrefai
- Division of Gastroenterology & Hepatology, Dept. of Medicine, University of Illinois at Chicago
- Jesse Brown VA Medical Center, Chicago, IL 60612
| | - Pradeep K. Dudeja
- Division of Gastroenterology & Hepatology, Dept. of Medicine, University of Illinois at Chicago
- Jesse Brown VA Medical Center, Chicago, IL 60612
| | - Seema Saksena
- Division of Gastroenterology & Hepatology, Dept. of Medicine, University of Illinois at Chicago
- Jesse Brown VA Medical Center, Chicago, IL 60612
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Okawada M, Wilson MW, Larsen SD, Lipka E, Hillfinger J, Teitelbaum DH. Blockade of the renin-angiotensin system prevents acute and immunologically relevant colitis in murine models. Pediatr Surg Int 2016; 32:1103-1114. [PMID: 27670279 DOI: 10.1007/s00383-016-3965-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/13/2016] [Indexed: 12/19/2022]
Abstract
BACKGROUND Blockade of the renin-angiotensin system (RAS) has been shown to alleviate inflammatory processes in the gastrointestinal tract. The aim of this study was to determine if blockade of the RAS would be effective in an immunologically relevant colitis model, and to compare outcome with an acute colitis model. METHODS A losartan analog, CCG-203025 (C23H26ClN3O5S) containing a highly polar sulfonic acid moiety that we expected would allow localized mucosal antagonism with minimal systemic absorption was selected as an angiotensin II type 1a receptor antagonist (AT1aR-A). Two colitis models were studied: (1) Acute colitis was induced in 8- to 10-week-old C57BL/6J mice by 2.5 % dextran sodium sulfate (DSS, in drinking water) for 7 days. (2) IL10-/-colitis Piroxicam (200 ppm) was administered orally in feed to 5-week-old IL-10-/-mice (C57BL/6J background) for 14 days followed by enalaprilat (ACE-I), CCG-203025 or PBS administered transanally for 14 days. RESULTS In the DSS model, weight loss and histologic score for CCG-203025 were better than with placebo. In the IL10-/-model, ACE-I suppressed histologic damage better than CCG-203025. Both ACE-I and CCG-203025 reduced pro-inflammatory cytokines and chemokines. CONCLUSIONS This study demonstrated the therapeutic efficacy of both ACE-I and AT1aR-A for preventing the development of both acute and immunologically relevant colitis.
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Affiliation(s)
- Manabu Okawada
- Section of Pediatric Surgery, Department of Surgery, The University of Michigan Medical School, Mott Children's Hospital, F3970, Ann Arbor, MI, 48109-0245, USA. .,Department of Pediatric General and Urogenital Surgery, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
| | - Michael W Wilson
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, 48109-1065, USA
| | - Scott D Larsen
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, 48109-1065, USA
| | - Elke Lipka
- Therapeutic Systems Research Laboratories, Inc, Ann Arbor, MI, 48108, USA
| | - John Hillfinger
- Therapeutic Systems Research Laboratories, Inc, Ann Arbor, MI, 48108, USA
| | - Daniel H Teitelbaum
- Section of Pediatric Surgery, Department of Surgery, The University of Michigan Medical School, Mott Children's Hospital, F3970, Ann Arbor, MI, 48109-0245, USA
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3
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Halici Z, Polat B, Cadirci E, Topcu A, Karakus E, Kose D, Albayrak A, Bayir Y. Inhibiting renin angiotensin system in rate limiting step by aliskiren as a new approach for preventing indomethacin induced gastric ulcers. Chem Biol Interact 2016; 258:266-75. [DOI: 10.1016/j.cbi.2016.09.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 09/07/2016] [Accepted: 09/15/2016] [Indexed: 01/01/2023]
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Sueyoshi R, Woods Ignatoski KM, Daignault S, Okawada M, Teitelbaum DH. Angiotensin converting enzyme-inhibitor reduces colitis severity in an IL-10 knockout model. Dig Dis Sci 2013; 58:3165-77. [PMID: 23949641 PMCID: PMC3859685 DOI: 10.1007/s10620-013-2825-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 07/23/2013] [Indexed: 02/06/2023]
Abstract
BACKGROUND We previously demonstrated angiotensin converting enzymes (ACE) over-expression in a dextran-sodium sulfate colitis model; ACE inhibitor (ACE-I) treatment reduced colitis severity in this model. However, ACE-I has not been tested in more immunologically relevant colitis models. AIM We hypothesized that ACE-I would decrease disease severity in an IL-10 knockout (-/-) colitis model. METHODS Colitis was induced by giving 10-week old IL-10-/- mice piroxicam (P.O.) for 14 days. The ACE-I enalaprilat was given transanally at a dose of 6.25 mg/kg for 21 days. Prednisolone (PSL) with or without enalaprilat were used as therapeutic, comparative groups. All groups were compared to a placebo treated group. Outcome measures were clinical course, histology, abundance of pro-inflammatory cytokines/chemokines, and epithelial barrier function. RESULTS Enalaprilat exhibited better survival (91 %) versus other treatment groups (PSL: 85.7 %, PSL + ACE-I: 71.4 %, placebo: 66.6 %). The ACE-I and PSL + ACE-I groups showed significantly better histological scores versus placebo mice. ACE-I and the PSL groups significantly reduced several pro-inflammatory cytokines versus placebo mice. FITC-dextran permeability was reduced in the ACE-I and PSL + ACE-I groups. Blood pressure was not affected in ACE-I treated mice compared to placebo mice. CONCLUSIONS ACE-I was effective in reducing severity of colitis in an IL-10-/- model. The addition of prednisolone minimally augmented this effect. The findings suggest that appropriately dosed ACE-I with or without steroids may be a new therapeutic agent for colitis.
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Affiliation(s)
- Ryo Sueyoshi
- Section of Pediatric Surgery, Department of Surgery, Mott Children’s Hospital, University of Michigan, 1540 E. Hospital Dr., SPC 4211, Ann Arbor, MI 48109-4211, USA
| | - Kathleen M. Woods Ignatoski
- Section of Pediatric Surgery, Department of Surgery, Mott Children’s Hospital, University of Michigan, 1540 E. Hospital Dr., SPC 4211, Ann Arbor, MI 48109-4211, USA
| | - Stephanie Daignault
- Biostatistics, Comprehensive Cancer Center, University of Michigan Health System, Ann Arbor, MI, USA
| | - Manabu Okawada
- Section of Pediatric Surgery, Department of Surgery, Mott Children’s Hospital, University of Michigan, 1540 E. Hospital Dr., SPC 4211, Ann Arbor, MI 48109-4211, USA
| | - Daniel H. Teitelbaum
- Section of Pediatric Surgery, Department of Surgery, Mott Children’s Hospital, University of Michigan, 1540 E. Hospital Dr., SPC 4211, Ann Arbor, MI 48109-4211, USA
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Kamel R, El Morsy EM, Awad AS. Immunomodulatory effect of candesartan on indomethacin-induced gastric ulcer in rats. Immunopharmacol Immunotoxicol 2012; 34:956-61. [DOI: 10.3109/08923973.2012.698283] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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6
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Okawada M, Koga H, Larsen SD, Showalter HD, Turbiak AJ, Jin X, Lucas PC, Lipka E, Hillfinger J, Kim JS, Teitelbaum DH. Use of enterally delivered angiotensin II type Ia receptor antagonists to reduce the severity of colitis. Dig Dis Sci 2011; 56:2553-65. [PMID: 21399927 PMCID: PMC3163034 DOI: 10.1007/s10620-011-1651-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Accepted: 02/16/2011] [Indexed: 12/15/2022]
Abstract
BACKGROUND Renin-angiotensin system blockade reduces inflammation in several organ systems. Having found a fourfold increase in angiotensin II type Ia receptor expression in a dextran sodium sulfate colitis model, we targeted blockade with angiotensin II type Ia receptor antagonists to prevent colitis development. Because hypotension is a major complication of angiotensin II type Ia receptor antagonists use, we hypothesized that use of angiotensin II type Ia receptor antagonists compounds which lack cell membrane permeability, and thus enteric absorption, would allow for direct enteral delivery at far higher concentrations than would be tolerated systemically, yet retain efficacy. METHODS Based on the structure of the angiotensin II type Ia receptor antagonist losartan, deschloro-losartan was synthesized, which has extremely poor cell membrane permeability. Angiotensin II type Ia receptor antagonist efficacy was evaluated by determining the ability to block NF-κB activation in vitro. Dextran sodium sulfate colitis was induced in mice and angiotensin II type Ia receptor antagonist efficacy delivered transanally was assessed. RESULTS In vitro, deschloro-losartan demonstrated near equal angiotensin II type Ia receptor blockade compared to losartan as well as another angiotensin II type Ia receptor antagonist, candesartan. In the dextran sodium sulfate model, each compound significantly improved clinical and histologic scores and epithelial cell apoptosis. Abundance of TNF-α, IL-1β, and IL6 mRNA were significantly decreased with each compound. In vitro and in vivo intestinal drug absorption, as well as measures of blood pressure and mucosal and colonic blood flow, showed significantly lower uptake of deschloro-losartan compared to losartan and candesartan. CONCLUSIONS This study demonstrated efficacy of high-dose angiotensin II type Ia receptor antagonists in this colitis model. We postulate that a specially designed angiotensin II type Ia receptor antagonist with poor oral absorption may have great potential as a new therapeutic agent for inflammatory bowel disease in the future.
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Affiliation(s)
- Manabu Okawada
- Section of Pediatric Surgery, Department of Surgery, The University of Michigan Medical School, Mott Children’s Hospital, F3970, Ann Arbor, MI 48109-0245, USA
| | - Hiroyuki Koga
- Section of Pediatric Surgery, Department of Surgery, The University of Michigan Medical School, Mott Children’s Hospital, F3970, Ann Arbor, MI 48109-0245, USA
| | - Scott D. Larsen
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109-1065, USA
| | - Hollis D. Showalter
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109-1065, USA
| | - Anjanette J. Turbiak
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109-1065, USA
| | - Xiaohong Jin
- Department of Pathology, The University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Peter C. Lucas
- Department of Pathology, The University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Elke Lipka
- Therapeutic Systems Research Laboratories, Inc, Ann Arbor, MI 48108, USA
| | - John Hillfinger
- Therapeutic Systems Research Laboratories, Inc, Ann Arbor, MI 48108, USA
| | - Jae Seung Kim
- Therapeutic Systems Research Laboratories, Inc, Ann Arbor, MI 48108, USA
| | - Daniel H. Teitelbaum
- Section of Pediatric Surgery, Department of Surgery, The University of Michigan Medical School, Mott Children’s Hospital, F3970, Ann Arbor, MI 48109-0245, USA
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Takagi T, Naito Y, Okada H, Okayama T, Mizushima K, Yamada S, Fukumoto K, Inoue K, Takaoka M, Oya-Ito T, Uchiyama K, Ishikawa T, Handa O, Kokura S, Yagi N, Ichikawa H, Kato Y, Osawa T, Yoshikawa T. Identification of dihalogenated proteins in rat intestinal mucosa injured by indomethacin. J Clin Biochem Nutr 2011; 48:178-82. [PMID: 21373273 PMCID: PMC3045693 DOI: 10.3164/jcbn.10-93] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 08/04/2010] [Indexed: 01/14/2023] Open
Abstract
Previous studies have shown that activated neutrophils and their myeloperoxidase (MPO)-derived products play a crucial role in the pathogenesis of non-steroidal anti-inflammatory drug (NSAID)-related small intestinal injury. The aim of the present study is to identify dihalogenated proteins in the small intestine on indomethacin administration. Intestinal damage was induced by subcutaneous administration of indomethacin (10 mg/kg) in male Wistar rats, and the severity of the injury was evaluated by measuring the area of visible ulcerative lesions. Tissue-associated MPO activity was measured in the intestinal mucosa as an index of neutrophil infiltration. The dihalogenated proteins were separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) using novel monoclonal antibodies against dibromotyrosine (DiBrY), and they were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) peptide mass fingerprinting and a Mascot database search. Single administration of indomethacin elicited increased ulcerative area and MPO activity in the small intestine. 2D-PAGE showed an increased level of DiBrY-modified proteins in the indomethacin-induced injured intestinal mucosa and 6 modified proteins were found. Enolase-1 and albumin were found to be DiBrY modified. These proteins may be responsible for the development of neutrophil-associated intestinal injury induced by indomethacin.
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Affiliation(s)
- Tomohisa Takagi
- Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
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8
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Yamada S, Naito Y, Takagi T, Mizushima K, Hirai Y, Horie R, Fukumoto K, Inoue K, Harusato A, Yoshida N, Uchiyama K, Handa O, Ishikawa T, Konishi H, Wakabayashi N, Yagi N, Kokura S, Kita M, Yoshikawa T. Reduced small-intestinal injury induced by indomethacin in interleukin-17A-deficient mice. J Gastroenterol Hepatol 2011; 26:398-404. [PMID: 21261732 DOI: 10.1111/j.1440-1746.2010.06496.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND AND AIMS The pathogenesis of enteropathy induced by non-steroidal anti-inflammatory drugs (NSAIDs) is still unclear, and there are no established treatments. Interleukin-17A (IL-17A) is a pro-inflammatory cytokine that has been associated with the development of chronic inflammatory diseases, including autoimmune diseases. To define the role of IL-17A in small intestinal injury and inflammation, we studied the effects of indomethacin administration in mice with targeted deletions of the IL-17A gene. METHODS Male C57BL/6 (wild-type) and homozygous IL-17A(-/-) C57BL/6 mice were subjected to this study. Indomethacin (10 mg/kg) was subcutaneously administered to induce small-intestinal damage. Indomethacin-induced lesions in the small intestine were evaluated by measuring the injured area and by histopathology. Also assessed were myeloperoxidase (MPO) activity, as an index of neutrophil accumulation, and intestinal mRNA expression for inflammatory cytokines. RESULTS The area of macroscopic ulcerative lesions, the MPO activity and the mRNA expression of inflammatory-associated chemokines, such as keratinocyte chemoattractant (KC), monocyte chemotactic protein-1 (MCP-1), and granulocyte-colony stimulating factor (G-CSF), were significantly increased in indomethacin-treated groups compared with the sham groups. The development of intestinal lesions by indomethacin was inhibited in IL-17A(-/-) mice compared with wild-type mice, together with significant suppression of the increased levels of MPO activities and KC, MCP-1, and G-CSF levels. CONCLUSION These findings demonstrate that IL-17A contributes to the development of indomethacin-induced small intestinal injury through upregulation of G-CSF, KC, and MCP-1. IL-17A might be a promising new therapeutic target to treat NSAID-induced enteritis.
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Affiliation(s)
- Shinya Yamada
- Department of Molecular Gastroenterology, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, Japan
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Abstract
The gastrointestinal (GI) tract is fundamental for the intake of fluid and electrolytes and accommodates a large proportion of bodily hemodynamics and host defence systems. Despite that the renin-angiotensin system (RAS) is a prominent regulatory system for fluid and electrolyte homeostasis its impact on GI physiology is only little explored. Recent data indicate that RAS is well expressed and active in the GI tract although exact physiological roles are to be settled. There are several reports showing influences by RAS and its key mediator angiotensin II (AngII) on intestinal epithelial fluid and electrolyte transport and data are accumulating, suggesting involvement in GI mucosal inflammation and carcinogenesis. Of particular interest is the increasing amount of experimental support for the involvement of AngII formation and actions via the AngII subtype 1 (AT1) receptor in the pathogenesis and treatment of inflammatory bowel disease. The picture of RAS in the GI tract is, however, far from complete. Because RAS is an important application area for reno-cardiovascular diseases, a number of pharmacological agents as well as research technologies already exist and can in the future be used for GI research. A marked expansion of knowledge concerning the role of RAS in GI physiology and pathophysiology is to be expected.
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Affiliation(s)
- L Fändriks
- Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, University of Gothenburg, Sweden.
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Menozzi A, Pozzoli C, Poli E, Passeri B, Gianelli P, Bertini S. Diazoxide attenuates indomethacin-induced small intestinal damage in the rat. Eur J Pharmacol 2010; 650:378-83. [PMID: 20950601 DOI: 10.1016/j.ejphar.2010.09.078] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 09/16/2010] [Accepted: 09/23/2010] [Indexed: 01/10/2023]
Abstract
ATP-sensitive potassium (K(ATP)) channel openers have been shown to protect against cellular damage in neurons, cardiac muscle, and kidney and to effectively reduce nonsteroidal anti-inflammatory drug (NSAID)-induced gastric damage in rats. We investigated the effects of K(ATP) channel opener diazoxide on small intestinal injury induced in rats by indomethacin administration. The effect of glibenclamide, a K(ATP) channel blocker, was also evaluated. Diazoxide (15, 45 and 135mg/kg) or glibenclamide (18mg/kg), were given by oral gavage 1h before and 6h after indomethacin treatment (20mg/kg p.o.). After 24h, macroscopic and histologic lesions, myeloperoxidase (MPO) activity and lipid peroxidation levels were evaluated. Diazoxide at 15mg/kg was ineffective, while at doses of 45mg/kg and 135mg/kg was able to significantly improve all damage parameters. Glibenclamide administration enhanced intestinal injury. These results show for the first time a beneficial effect of diazoxide in indomethacin-induced enteritis in the rat. Several mechanisms, such as oxidative phosphorylation uncoupling and hypermotility seem particularly important in NSAID-induced intestinal injury. Such events lead to increased mucosal permeability and to penetration of noxious lumen components, which ignite the inflammatory response. Since K(ATP) channel openers were shown to protect against mitochondrial damage, to reduce intercellular permeability and to relax smooth muscle, we suggest that diazoxide could exert its beneficial effects by one or more of these actions.
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Hallersund P, Helander HF, Casselbrant A, Edebo A, Fändriks L, Elfvin A. Angiotensin II receptor expression and relation to Helicobacter pylori-infection in the stomach of the Mongolian gerbil. BMC Gastroenterol 2010; 10:3. [PMID: 20074344 PMCID: PMC2823647 DOI: 10.1186/1471-230x-10-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Accepted: 01/14/2010] [Indexed: 12/20/2022] Open
Abstract
Background The role of the renin-angiotensin system in gastric physiology and disease has as yet been sparsely explored. The first aim of the study was to investigate the baseline presence and location of angiotensin II receptors (AT1R and AT2R) in the stomach of the Mongolian gerbil. A second aim was to elucidate whether the presence of H. pylori infection is associated with changes in the expression of these receptors. Methods H. pylori-negative and H. pylori-infected (strain SS1 or TN2GF4) male Mongolian gerbils were investigated. The stomachs were examined at six or 12 months after inoculation by the use of immunohistochemistry, western blot and microscopic morphometry. Results AT1R and AT2R were located in a variety of cells in the gerbil gastric wall, including a subpopulation of endocrine cells in the antral mucosa and inflammatory cells infiltrating H. pylori-infected stomachs. Gerbils infected with the SS1 strain showed a significantly increased antral AT1R protein expression and an increased number of infiltrating polymorphonuclear leucocytes (PMNs) at 12 months. The AT1R protein expression correlated with the number of PMNs and the antral expression of myeloperoxidase. Conclusions Angiotensin II receptors are present in a variety of cells in the gastric wall of the Mongolian gerbil. The results indicate an influence dependent on the H. pylori strain on the gastric AT1R expression and a relationship between gastric AT1R expression and mucosal PMNs infiltration.
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Affiliation(s)
- Peter Hallersund
- Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.
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