1
|
Luo P, Li X, Gao Y, Chen Z, Zhang Q, Wang Z, Tian X. Central administration of human opiorphin alleviates dextran sodium sulfate-induced colitis in mice through activation of the endogenous opioid system. Front Pharmacol 2022; 13:904926. [PMID: 36176442 PMCID: PMC9513434 DOI: 10.3389/fphar.2022.904926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 08/17/2022] [Indexed: 11/18/2022] Open
Abstract
The opioid system plays a crucial role in maintaining gastrointestinal homeostasis. Endogenous opioid peptide enkephalins have anti-inflammatory effect and participate in the treatment of inflammatory bowel diseases (IBDs). Here, we investigated the effect of natural enkephalinase inhibitor human opiorphin (HO) on dextran sodium sulfate (DSS)-induced colitis in mice. Our results showed that central administration of HO attenuated DSS-induced colitis, as indicated by the reduction of disease activity index (DAI) scores, macroscopic scores, histological scores, and the myeloperoxidase (MPO) activity. Moreover, HO alleviated DSS-induced inflammation by decreasing inflammatory cytokines TNF-α, IL-6, and IL-1β, and increasing anti-inflammatory cytokine IL-10 in both serum and colon tissues in DSS-treated mice. The potential anti-inflammatory effect of HO at a dose of 40 μg/kg was observed as evidenced by a decrease in nuclear factor κB (NF-κB) p65, toll-like receptor-4 (TLR-4), iNOS, and COX-2. HO also improved intestinal barrier function by enhancing the expression of tight junction proteins. Furthermore, HO treatment significantly inhibited activities of neutral endopeptidase (NEP) and aminopeptidase N (APN), elevated serum enkephalins concentrations, and increased expressions of mu and delta opioid receptors. In addition, pretreatment with opioid receptor antagonist naloxone hydrochloride (NH) compromised the protective effect of HO and aggravated colitis symptoms, as indicated by inhibited anti-inflammatory effects, disrupted intestinal barrier function, and decreased opioid receptor activity. In conclusion, these data indicate that HO protects against DSS-induced colitis by inhibiting TLR4/NF-κB pathway activation and improving intestinal barrier function through activation of the endogenous opioid system. Therefore, targeting the opioid system with peptidase inhibitors intervention would be a novel strategy in the therapy of IBD.
Collapse
Affiliation(s)
- Pan Luo
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou, China
| | - Xuelin Li
- National Demonstration Center for Experimental Biology Education, School of Life Science, Lanzhou University, Lanzhou, China
| | - Yuan Gao
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou, China
| | - Zhengjun Chen
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou, China
| | - Quanwei Zhang
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou, China
- *Correspondence: Quanwei Zhang, ; Zhimin Wang, ; Xiaozhu Tian,
| | - Zhimin Wang
- Gansu Provincial Hospital PET/CT Center, Lanzhou, China
- *Correspondence: Quanwei Zhang, ; Zhimin Wang, ; Xiaozhu Tian,
| | - Xiaozhu Tian
- National Demonstration Center for Experimental Biology Education, School of Life Science, Lanzhou University, Lanzhou, China
- *Correspondence: Quanwei Zhang, ; Zhimin Wang, ; Xiaozhu Tian,
| |
Collapse
|
2
|
Szymaszkiewicz A, Storr M, Fichna J, Zielinska M. Enkephalinase inhibitors, potential therapeutics for the future treatment of diarrhea predominant functional gastrointestinal disorders. Neurogastroenterol Motil 2019; 31:e13526. [PMID: 30549162 DOI: 10.1111/nmo.13526] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 10/20/2018] [Accepted: 11/12/2018] [Indexed: 02/08/2023]
Abstract
The endogenous opioid system (EOS) is considered being a crucial element involved in the pathophysiology of irritable bowel syndrome (IBS) as it regulates gastrointestinal (GI) homeostasis through modulation of motility and water and ion secretion/absorption. Along with opioid receptors (ORs), the following components of EOS can be distinguished: 1. endogenous opioid peptides (EOPs), namely enkephalins, endorphins, endomorphins and dynorphins, and 2. peptidases, which regulate the metabolism (synthesis and degradation) of EOPs. Enkephalins, which are δ-opioid receptors agonists, induce significant effects in the GI tract as they act as potent pro-absorptive neurotransmitters. The action of enkephalins and other EOPs is limited, since EOPs are easily and rapidly inactivated by a natural metalloendopeptidase (enkephalinase/neprilysin) and aminopeptidase N. Studies show that the activity of EOPs can be enhanced by inhibition of these enzymes. In this review, we discuss the antidiarrheal and antinociceptive potential of enkephalinase inhibitors. Furthermore, our review is to answer the question whether enkephalinase inhibitors may be helpful in the future treatment of diarrhea predominant functional GI disorders.
Collapse
Affiliation(s)
- Agata Szymaszkiewicz
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Lodz, Poland
| | - Martin Storr
- Department of Medicine, Ludwig Maximilians University Munich, Munich, Germany.,Center of Endoscopy, Starnberg, Germany
| | - Jakub Fichna
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Lodz, Poland
| | - Marta Zielinska
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Lodz, Poland
| |
Collapse
|
3
|
Eberlin M, Chen M, Mueck T, Däbritz J. Racecadotril in the treatment of acute diarrhea in children: a systematic, comprehensive review and meta-analysis of randomized controlled trials. BMC Pediatr 2018; 18:124. [PMID: 29614995 PMCID: PMC5883268 DOI: 10.1186/s12887-018-1095-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 03/20/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Racecadotril is a guideline-recommended option for the treatment of acute diarrhea in children but existing guidelines and previous reviews of the field are based on a small fraction of published evidence. Therefore, we have performed a systematic search for randomized controlled trials evaluating racecadotril as add-on or in comparison to other treatments. METHODS A search was performed in PubMed, Scopus and Google Scholar without limits about country of origin or reporting language. A meta-analysis was conducted for the five most frequently used efficacy parameters. RESULTS We have retrieved 58 trials, from nine countries including six in comparison to placebo, 15 in comparison to various active treatments and 41 as add-on to various standard treatments (some multi-armed studies allowing more than one comparison). Trials used 45 distinct efficacy parameters, most often time to cure, % of cured children after 3 days of treatment, global efficacy and number of stools on second day of treatment. Racecadotril was superior to comparator treatments in outpatients and hospitalized patients with a high degree of consistency as confirmed by meta-analysis for the five most frequently used outcome parameters. For instance, it reduced time to cure from 106.2 h to 78.2 h (mean reduction 28.0 h; P < 0.0001 in 24 studies reporting on this parameter). Tolerability of racecadotril was comparable to that of placebo (10.4% vs. 10.6% adverse events incidence) or that of active comparator treatments other than loperamide (2.4% in both groups). CONCLUSIONS Based on a comprehensive review of the existing evidence, we conclude that racecadotril is more efficacious than other treatments except for loperamide and has a tolerability similar to placebo and better than loperamide. These findings support the use of racecadotril in the treatment of acute diarrhea in children.
Collapse
Affiliation(s)
- Marion Eberlin
- Department of Medical Affairs CHC GSA, Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany
| | - Min Chen
- Department of Anesthesiology, Wuhan Union Hospital, Wuhan, China
| | - Tobias Mueck
- Department of Medical Affairs CHC GSA, Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany
| | - Jan Däbritz
- Department of Pediatrics, University Hospital Rostock, Rostock, Germany
- Center for Immunobiology, Blizard Institute, Barts Cancer Institute, The Barts and the London School of Medicine & Dentistry, Queen Mary University, London, UK
| |
Collapse
|
4
|
Fischbach W, Andresen V, Eberlin M, Mueck T, Layer P. A Comprehensive Comparison of the Efficacy and Tolerability of Racecadotril with Other Treatments of Acute Diarrhea in Adults. Front Med (Lausanne) 2016; 3:44. [PMID: 27790616 PMCID: PMC5064048 DOI: 10.3389/fmed.2016.00044] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 09/20/2016] [Indexed: 12/27/2022] Open
Abstract
Racecadotril is a guideline-recommended treatment to alleviate symptoms of acute diarrhea. A systematic review of randomized studies was performed comparing efficacy and safety of treatment with racecadotril to that with placebo or active treatments in adults. In five double-blind studies, racecadotril and placebo had comparable tolerability, but racecadotril was more effective. This was consistent across multiple efficacy parameters including duration of diarrhea, number of diarrheic stools, abdominal pain, and meteorism; it was also consistent across countries in Africa, Asia, and Europe. In six randomized studies in outpatients comparing racecadotril to loperamide, resolution of symptoms occurred with similar speed and efficacy; however, racecadotril treatment was associated with less rebound constipation and less abdominal discomfort. The seventh comparative study performed in geriatric nursing home residents reported a superior efficacy of racecadotril. In direct comparison with Saccharomyces boulardii treatment, racecadotril exhibited similar tolerability but was more efficacious. One study compared racecadotril to octreotide in patients with acute diarrhea requiring hospitalization, rehydration, and antibiotic treatment; in this cohort, octreotide was more efficacious than racecadotril. In conclusion, in adults with acute diarrhea, racecadotril is more efficacious than placebo or S. boulardii, similarly efficacious as loperamide and, in patients with moderate to severe disease as add-on to antibiotics, less than octreotide. The tolerability of racecadotril is similar to that of placebo or S. boulardii and better than that of loperamide, particularly with regard to risk of rebound constipation. Taken together, these data demonstrate that racecadotril is a suitable treatment to alleviate symptoms of acute diarrhea in adults.
Collapse
Affiliation(s)
- Wolfgang Fischbach
- Medizinische Klinik II, Klinikum Aschaffenburg-Alzenau, Aschaffenburg, Germany
| | - Viola Andresen
- Medizinische Klinik, Israelitisches Krankenhaus, Hamburg, Germany
| | - Marion Eberlin
- Department of Medical Affairs CHC Germany, Boehringer Ingelheim Pharma GmbH & Co KG, Ingelheim, Germany
| | - Tobias Mueck
- Department of Medical Affairs CHC Germany, Boehringer Ingelheim Pharma GmbH & Co KG, Ingelheim, Germany
| | - Peter Layer
- Medizinische Klinik, Israelitisches Krankenhaus, Hamburg, Germany
| |
Collapse
|
5
|
Griggs DW, Prinsen MJ, Oliva J, Campbell MA, Arnett SD, Tajfirouz D, Ruminski PG, Yu Y, Bond BR, Ji Y, Neckermann G, Choy RKM, de Hostos E, Meyers MJ. Pharmacologic Comparison of Clinical Neutral Endopeptidase Inhibitors in a Rat Model of Acute Secretory Diarrhea. J Pharmacol Exp Ther 2016; 357:423-31. [PMID: 26907621 PMCID: PMC4851326 DOI: 10.1124/jpet.115.231167] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/17/2016] [Indexed: 12/15/2022] Open
Abstract
Racecadotril (acetorphan) is a neutral endopeptidase (NEP) inhibitor with known antidiarrheal activity in animals and humans; however, in humans, it suffers from shortcomings that might be improved with newer drugs in this class that have progressed to the clinic for nonenteric disease indications. To identify potentially superior NEP inhibitors with immediate clinical utility for diarrhea treatment, we compared their efficacy and pharmacologic properties in a rat intestinal hypersecretion model. Racecadotril and seven other clinical-stage inhibitors of NEP were obtained or synthesized. Enzyme potency and specificity were compared using purified peptidases. Compounds were orally administered to rats before administration of castor oil to induce diarrhea. Stool weight was recorded over 4 hours. To assess other pharmacologic properties, select compounds were orally administered to normal or castor oil–treated rats, blood and tissue samples collected at multiple time points, and active compound concentrations determined by mass spectroscopy. NEP enzyme activity was measured in tissue homogenates. Three previously untested clinical NEP inhibitors delayed diarrhea onset and reduced total stool output, with little or no effect on intestinal motility assessed by the charcoal meal test. Each was shown to be a potent, highly specific inhibitor of NEP. Each exhibited greater suppression of NEP activity in intestinal and nonintestinal tissues than did racecadotril and sustained this inhibition longer. These results suggest that newer clinical-stage NEP inhibitors originally developed for other indications may be directly repositioned for treatment of acute secretory diarrhea and offer advantages over racecadotril, such as less frequent dosing and potentially improved efficacy.
Collapse
Affiliation(s)
- David W Griggs
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Michael J Prinsen
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Jonathan Oliva
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Mary A Campbell
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Stacy D Arnett
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Deena Tajfirouz
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Peter G Ruminski
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Ying Yu
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Brian R Bond
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Yuhua Ji
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Georg Neckermann
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Robert K M Choy
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Eugenio de Hostos
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Marvin J Meyers
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| |
Collapse
|
6
|
Fujita W, Gomes I, Dove LS, Prohaska D, McIntyre G, Devi LA. Molecular characterization of eluxadoline as a potential ligand targeting mu-delta opioid receptor heteromers. Biochem Pharmacol 2014; 92:448-56. [PMID: 25261794 PMCID: PMC4769596 DOI: 10.1016/j.bcp.2014.09.015] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 09/16/2014] [Accepted: 09/17/2014] [Indexed: 12/21/2022]
Abstract
Eluxadoline, an orally active mixed μ opioid receptor (μOR) agonist δ opioid receptor (δOR) antagonist developed for the treatment of diarrhea-predominant irritable bowel syndrome, normalizes gastrointestinal (GI) transit and defecation under conditions of novel environment stress or post-inflammatory altered GI function. Furthermore, compared to loperamide, which is used to treat non-specific diarrhea, the effects of eluxadoline on GI transit occur over a wider dosage range. However, the mechanisms of action of eluxadoline are unclear. In this study, we compared the ability of eluxadoline and loperamide to activate G-protein- and β-arrestin-mediated signaling at μOR homomers or μOR-δOR heteromers in heterologous cells. We also examined the ability of both compounds to reduce castor oil induced diarrhea in wild type (WT) and mice lacking δOR. We find that eluxadoline is more potent than loperamide in eliciting G-protein activity and β-arrestin recruitment in μOR expressing cells. However, in cells expressing μOR-δOR heteromers, the potency of eluxadoline is higher, but its maximal effect is lower than that of loperamide. Moreover, in these cells the signaling mediated by eluxadoline but not loperamide is reduced by μOR-δOR heteromer-selective antibodies. We find that in castor oil-induced diarrhea eluxadoline is more efficacious compared to loperamide in WT mice, and δOR appears to play a role in this process. Taken together these results indicate that eluxadoline behaves as a potent μOR agonist in the absence of δOR, while in the presence of δOR eluxadoline's effects are mediated through the μOR-δOR heteromer.
Collapse
MESH Headings
- Animals
- Arrestins/metabolism
- Castor Oil/adverse effects
- Diarrhea/chemically induced
- Diarrhea/drug therapy
- Humans
- Imidazoles/pharmacology
- Ligands
- Loperamide/pharmacology
- Male
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Phenylalanine/analogs & derivatives
- Phenylalanine/pharmacology
- Protein Multimerization
- Receptors, Opioid, delta/antagonists & inhibitors
- Receptors, Opioid, delta/genetics
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/metabolism
- Signal Transduction/drug effects
- beta-Arrestins
Collapse
Affiliation(s)
- Wakako Fujita
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ivone Gomes
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Leonard S Dove
- Furiex Pharmaceuticals, Inc., 3900 Paramount Parkway, Suite 150, Morrisville, NC 27560, USA
| | - David Prohaska
- Furiex Pharmaceuticals, Inc., 3900 Paramount Parkway, Suite 150, Morrisville, NC 27560, USA
| | - Gail McIntyre
- Furiex Pharmaceuticals, Inc., 3900 Paramount Parkway, Suite 150, Morrisville, NC 27560, USA
| | - Lakshmi A Devi
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| |
Collapse
|
7
|
Eberlin M, Mück T, Michel MC. A comprehensive review of the pharmacodynamics, pharmacokinetics, and clinical effects of the neutral endopeptidase inhibitor racecadotril. Front Pharmacol 2012; 3:93. [PMID: 22661949 PMCID: PMC3362754 DOI: 10.3389/fphar.2012.00093] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 04/27/2012] [Indexed: 11/15/2022] Open
Abstract
Racecadotril, via its active metabolite thiorphan, is an inhibitor of the enzyme neutral endopeptidase (NEP, EC 3.4.24.11), thereby increasing exposure to NEP substrates including enkephalins and atrial natriuretic peptide (ANP). Upon oral administration racecadotril is rapidly and effectively converted into the active metabolite thiorphan, which does not cross the blood–brain-barrier. Racecadotril has mainly been tested in animal models and patients of three therapeutic areas. As an analgesic the effects of racecadotril across animal models were inconsistent. In cardiovascular diseases such as hypertension or congestive heart failure results from animal studies were promising, probably related to increased exposure to ANP, but clinical results have not shown substantial therapeutic benefit over existing treatment options in cardiovascular disease. In contrast, racecadotril was consistently effective in animal models and patients with various forms of acute diarrhea by inhibiting pathologic (but not basal) secretion from the gut without changing gastro-intestinal transit time or motility. This included studies in both adults and children. In direct comparative studies with loperamide in adults and children, racecadotril was at least as effective but exhibited fewer adverse events in most studies, particularly less rebound constipation. Several guidelines recommend the use of racecadotril as addition to oral rehydration treatment in children with acute diarrhea.
Collapse
Affiliation(s)
- Marion Eberlin
- Department of Medical Affairs Germany, Boehringer Ingelheim Pharma GmbH & Co KG Ingelheim, Germany
| | | | | |
Collapse
|
8
|
Tian XZ, Chen J, Xiong W, He T, Chen Q. Effects and underlying mechanisms of human opiorphin on colonic motility and nociception in mice. Peptides 2009; 30:1348-54. [PMID: 19442408 DOI: 10.1016/j.peptides.2009.04.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Revised: 03/31/2009] [Accepted: 04/02/2009] [Indexed: 11/24/2022]
Abstract
In the present study, we investigated the effects of human opiorphin on colonic motility and nociception in mice. In in vitro bioassay, opiorphin (10(-6) to 10(-4)M) caused colonic contraction in a concentration-dependent manner, which was completely blocked by naloxone and partially attenuated by beta-funaltrexamine and naltrindole. Moreover, opiorphin (10(-4)M) significantly enhanced the contractile response induced by Met-enkephalin. The data suggested that the effect of opiorphin on colonic contraction may be due to the protection of enkephalins. In in vivo bioassay, intracerebroventricular (i.c.v.) administration of opiorphin (1.25-10 microg/kg) dose- and time-dependently induced potent analgesic effect (ED(50)=3.22 microg/kg). This effect was fully blocked by naloxone and significantly inhibited by co-injection (i.c.v.) with beta-funaltrexamine or naltrindole, but not by nor-binaltorphimine, indicating the involvement of both mu- and delta-opioid receptors in the analgesic response evoked by opiorphin. In addition, i.c.v. administration of 5 microg/kg opiorphin produced the comparative effect as 10 microg/kg morphine on the analgesia, suggesting that opiorphin displayed more potent analgesic effect than that induced by morphine.
Collapse
Affiliation(s)
- Xiao-zhu Tian
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou, 730000, PR China
| | | | | | | | | |
Collapse
|
9
|
Monteil T, Danvy D, Plaquevent JC, Duhamel L, Duhamel P, Gros C, Schwartz JC, Lecomte JM. NEW ASYMMETRIC SYNTHESIS OF DEXECADOTRIL AND ECADOTRIL STARTING FROM A SINGLE PRECURSOR. SYNTHETIC COMMUN 2006. [DOI: 10.1081/scc-100000201] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
10
|
Noble F, Banisadr G, Jardinaud F, Popovici T, Lai-Kuen R, Chen H, Bischoff L, Parsadaniantz SM, Fournie-Zaluski MC, Roques BP. First discrete autoradiographic distribution of aminopeptidase N in various structures of rat brain and spinal cord using the selective iodinated inhibitor [125I]RB 129. Neuroscience 2001; 105:479-88. [PMID: 11672613 PMCID: PMC7126477 DOI: 10.1016/s0306-4522(01)00185-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The selective and potent aminopeptidase N inhibitor [125I]RB 129 has been used for the radioautographic localization of this enzyme in rat brain, spinal cord and intestine. Brain microvessels and intestine brush-border cells were shown to present a high concentration of aminopeptidase N. Moreover, a labeling of various brain structures was observed. A very high level of binding occurred in the meninges, choroid plexus, pineal gland, paraventricular nucleus and pituitary gland. Moderate to high labeling was also observed in the cortex, caudate-putamen, subthalamic nucleus, central periaqueductal gray, thalamus, as well as in the dorsal and ventral horn of the spinal cord, which are known to contain a high concentration of enkephalins, opioid receptors and neutral endopeptidase. This co-localization confirms the physiological implication of aminopeptidase N in the inactivation of enkephalins accounting for the requirement of dual inhibition of neutral endopeptidase and aminopeptidase N to observe highly significant morphine-like effects induced by the protected endogenous opioid peptides. Aminopeptidase N was also visualized in moderate to high levels in other brain structures such as the hippocampus, nucleus accumbens, substantia nigra, hypothalamus (dorsomedial and ventromedial nuclei), raphe nucleus, pontine nucleus, inferior olive, and in high concentration in the granular layer of cerebellum. In summary, aminopeptidase N has been visualized for the first time in numerous brain areas using the selective inhibitor [125I]RB 129. This iodinated probe could allow the ex vivo and in vivo localization of aminopeptidase N in various tissues to be investigated and may also be used to evaluate quantitative changes in aminopeptidase N expression in pathological situations. Aminopeptidase N, which preferably removes NH2-terminal neutral amino acids from peptides, has probably a host of substrates. Nevertheless, a certain in vivo selectivity could be achieved by the presence of the enzyme in structures where the peptide effector and its receptors are also co-localized.
Collapse
Affiliation(s)
- F Noble
- Département de Pharmacochimie Moléculaire et Structurale, INSERM U266, CNRS UMR 8600, UFR des Sciences Pharmaceutiques et Biologiques, Paris, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Cézard JP, Duhamel JF, Meyer M, Pharaon I, Bellaiche M, Maurage C, Ginies JL, Vaillant JM, Girardet JP, Lamireau T, Poujol A, Morali A, Sarles J, Olives JP, Whately-Smith C, Audrain S, Lecomte JM. Efficacy and tolerability of racecadotril in acute diarrhea in children. Gastroenterology 2001; 120:799-805. [PMID: 11231932 DOI: 10.1053/gast.2001.22544] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Oral rehydration therapy is the only treatment recommended by the World Health Organization in acute diarrhea in children. Antisecretory drugs available could not be used because of their side effects, except for racecadotril, which is efficient in acute diarrhea in adults. METHODS The efficacy and tolerability of racecadotril (1.5 mg/kg administered orally 3 times daily) as adjuvant therapy to oral rehydration were compared with those of placebo in 172 infants aged 3 months to 4 years (mean age, 12.8 months) who had acute diarrhea. The treatment groups were comparable in terms of age, duration of diarrhea, number of stools, and causative microorganism at inclusion. RESULTS During the first 48 hours of treatment, patients receiving racecadotril had a significantly lower stool output (grams per hour) than those receiving placebo. The 95% confidence interval was 43%-88% for the full data set (n = 166; P = 0.009) and 33%-75% for the per-protocol population (n = 116; P = 0.001). There was no difference between treatments depending on rotavirus status. Significant differences between treatment groups were also found after 24 hours of treatment: full data set (n = 167; P = 0.026) and per-protocol population (n = 121; P = 0.015). Tolerability was good in both groups of patients. CONCLUSIONS This study demonstrates the efficacy (up to 50% reduction in stool output) and tolerability of racecadotril as adjuvant therapy to oral rehydration solution in the treatment of severe diarrhea in infants and children.
Collapse
Affiliation(s)
- J P Cézard
- Pediatric Gastroenterology Unit, Paris, France.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Salazar-Lindo E, Santisteban-Ponce J, Chea-Woo E, Gutierrez M. Racecadotril in the treatment of acute watery diarrhea in children. N Engl J Med 2000; 343:463-7. [PMID: 10944563 DOI: 10.1056/nejm200008173430703] [Citation(s) in RCA: 180] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Racecadotril (acetorphan), an enkephalinase inhibitor with antisecretory and antidiarrheal actions, is an effective and safe treatment for acute diarrhea in adults and children. Whether treatment with racecadotril and oral rehydration therapy is more effective than treatment with oral rehydration alone in hospitalized children with acute watery diarrhea is not known. METHODS We treated 135 boys 3 to 35 months of age who had watery diarrhea of five days' duration or less with racecadotril (1.5 mg per kilogram of body weight orally every eight hours) or placebo, in addition to oral rehydration solution. The primary end point was the 48-hour stool output (measured in grams); the total stool output, duration of diarrhea, and total intake of oral rehydration solution were also measured. RESULTS The mean (+/-SE) 48-hour stool output was 92+/-12 g per kilogram in the racecadotril group and 170+/-15 g per kilogram in the placebo group (P<0.001), a 46 percent reduction with racecadotril. The results were similar among the 73 boys with rotavirus infections. The total stool output was 157+/-27 g per kilogram in the racecadotril group and 331+/-39 g per kilogram in the placebo group (P<0.001). The median duration of diarrhea was significantly less (P<0.001) in the racecadotril group (28 hours regardless of rotavirus status) than in the placebo group (72 and 52 hours, respectively, for rotavirus-positive and rotavirus-negative patients). The intake of oral rehydration solution was significantly lower in the racecadotril group than in the placebo group (P<0.001). Racecadotril was well tolerated; only seven patients taking racecadotril had adverse effects, which were all mild and transient. CONCLUSIONS In young boys with acute watery diarrhea, racecadotril is an effective and safe treatment.
Collapse
Affiliation(s)
- E Salazar-Lindo
- Department of Pediatrics, Hospital Nacional Cayetano Heredia, Lima, Peru.
| | | | | | | |
Collapse
|
13
|
Abstract
Racecadotril is an oral enkephalinase inhibitor used in the treatment of acute diarrhoea. It prevents the degradation of endogenous opioids (enkephalins), thereby reducing hypersecretion of water and electrolytes into the intestinal lumen. In a randomised double-blind study in 6 adult volunteers with castor oil-induced diarrhoea, racecadotril significantly reduced stool weight and stool number in comparison with placebo. Similar results have been obtained in treating castor oil-induced diarrhoea in rats. Racecadotril was significantly more effective than placebo in randomised double-blind studies in adults or children with diarrhoea (of infectious origin or in adults with HIV infection). In well controlled trials, racecadotril had efficacy similar to that of loperamide and was generally as effective as loperamide-oxide. Racecadotril had a similar tolerability profile to placebo, and was better tolerated than loperamide, in adults and children with diarrhoea. It caused significantly less constipation after resolution of diarrhoea than loperamide.
Collapse
Affiliation(s)
- A J Matheson
- Adis International Limited, Mairangi Bay, Auckland, New Zealand.
| | | |
Collapse
|
14
|
Abstract
Since preclinical studies had indicated the potential efficacy and tolerability of racecadotril for the treatment of diarrhoea in man, a series of studies was carried out to assess the clinical effects of racecadotril. These studies were also designed to evaluate whether racecadotril possessed the clinical properties that had been previously identified for an ideal agent to treat infectious diarrhoea. The pure antisecretory action of racecadotril was confirmed in these clinical studies, as was the drug's rapid onset of action. The high therapeutic index of racecadotril was combined with a lack of effect on the central nervous system. Finally, racecadotril was found to be effective in treating acute diarrhoea in double-blind studies against both placebo and the mu opiate receptor agonist, loperamide. The efficacy of racecadotril in acute diarrhoea was not associated with adverse gastrointestinal effects, and its adverse events profile was similar to that of placebo. It was concluded that racecadotril offers a new approach to the treatment of diarrhoea via its mechanism of action as a true antisecretory agent.
Collapse
Affiliation(s)
- J M Lecomte
- Bioprojet, 30 rue des Francs-Bourgeois, Paris, France
| |
Collapse
|
15
|
Abstract
Since enkephalins were discovered in 1975, it has become clear that they play an antisecretory role in the gastrointestinal tract. Hence a rational research programme was directed at the development of a drug that would preserve these neurotransmitter peptides in the gut by preventing their inactivation. This research programme has resulted in the development of the enkephalinase inhibitor, racecadotril. Preclinical studies have demonstrated the efficacy of racecadotril in two models of hypersecretory diarrhoea: infusion of cholera toxin and castor oil-induced diarrhoea. Moreover, unlike loperamide, racecadotril did not prolong transit time in the small intestine or colon. Further experiments have shown that racecadotril does not promote bacterial overgrowth in the small intestine. Racecadotril lacks any potential for neurotoxicity, and radiolabelled studies have demonstrated that the drug does not enter the brain after oral administration. No potential for abuse or physical dependence has been seen. It is concluded that racecadotril demonstrates specificity of antisecretory action on the gastrointestinal tract without any adverse effect on gastrointestinal motility, and that the results of the preclinical studies indicate the potential usefulness in the treatment of hypersecretory diarrhoea in man.
Collapse
Affiliation(s)
- J C Schwartz
- Unité de Neurobiologie et Pharmacologie Moléculaire (U-109) de l'INSERM, Centre Paul Broca, 2ter rue d'Alésia, 75014, Paris, France.
| |
Collapse
|
16
|
Hamza H, Ben Khalifa H, Baumer P, Berard H, Lecomte JM. Racecadotril versus placebo in the treatment of acute diarrhoea in adults. Aliment Pharmacol Ther 1999; 13 Suppl 6:15-9. [PMID: 10646047 DOI: 10.1046/j.1365-2036.1999.00002.x-i1] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
METHODS A two-centre, double-blind, parallel-group, randomized study was carried out to compare the efficacy and tolerability of racecadotril (100 mg three times daily) and placebo in 70 adult patients with acute diarrhoea. An objective criterion of antisecretory activity, stool weight, was used. RESULTS Racecadotril produced a significant (P = 0.025) decrease in stool weight during the first day of treatment compared with placebo, and was also associated with significantly fewer diarrhoeic stools than placebo after 1 day of treatment (p = 0.027). Racecadotril and placebo were equally well tolerated, and the frequency of symptoms and signs was similar in both groups after 4 days of treatment. Fewer patients on racecadotril suffered from abdominal distension following treatment (5.6% vs. 18.2% on placebo). CONCLUSIONS Racecadotril acts rapidly to resolve acute diarrhoea and has an incidence of adverse events similar to that of placebo.
Collapse
Affiliation(s)
- H Hamza
- Taoufik Clinic, Tunis, Tunisia
| | | | | | | | | |
Collapse
|
17
|
Primi MP, Bueno L, Baumer P, Berard H, Lecomte JM. Racecadotril demonstrates intestinal antisecretory activity in vivo. Aliment Pharmacol Ther 1999; 13 Suppl 6:3-7. [PMID: 10646045 DOI: 10.1046/j.1365-2036.13.s6.3.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Racecadotril (acetorphan), a potent enkephalinase inhibitor, protects endogenous enkephalins from degradation. Racecadotril exhibits experimental and clinical antidiarrhoeal activity without any effect on intestinal motility, suggesting selective antisecretory activity. The antisecretory effect of racecadotril was directly assessed in the present study. METHODS A 1 m, jejunal, Thiry-Vella loop was created in six mongrel dogs, and water and ionic fluxes were evaluated during infusion (2 mL/min) of Tyrode solution labelled with 14C-polyethylene glycol. Fluxes were determined both in the basal state and 5-6 h after commencement of a 2-h infusion of cholera toxin (0.4 microgram/mL). Racecadotril (10 mg/kg) or vehicle was given orally with and without prior intravenous administration of naloxone (0.1 mg/kg) or phentolamine (0.2 mg/kg). RESULTS Basal absorption remained unchanged following racecadotril administration; however, racecadotril significantly decreased (P = 0.01) cholera toxin-induced water, sodium, and potassium hypersecretion, from 0.73 +/- 0.15 to 0.37 +/- 0.13 mL/min; from 125.0 +/- 16.1 to 14.7 +/- 9.5 microMol/min; and from 3.41 +/- 0.66 to 1.66 +/- 0.61 microMol/min, respectively. This antisecretory activity of racecadotril was suppressed by naloxone but not by phentolamine. CONCLUSIONS This study directly demonstrates the antisecretory activity of racecadotril in relation to the protection of endogenous enkephalins.
Collapse
Affiliation(s)
- M P Primi
- Department of Pharmacology, Institut National de la Recherche Agronomique, Toulouse, France.
| | | | | | | | | |
Collapse
|
18
|
Vetel JM, Berard H, Fretault N, Lecomte JM. Comparison of racecadotril and loperamide in adults with acute diarrhoea. Aliment Pharmacol Ther 1999; 13 Suppl 6:21-6. [PMID: 10646048 DOI: 10.1046/j.1365-2036.1999.00003.x-i1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
METHODS A multicentre, randomized, double-blind, double-placebo, parallel-group study was carried out to compare the efficacy, tolerability, and safety of racecadotril (100 mg three times daily) and loperamide (2 mg after each diarrhoeic stool) in 157 adults with acute diarrhoea. Patients were treated for 7 days or until recovery, if this took place earlier. RESULTS Both groups of patients passed similar numbers (mean +/- S.E.M.) of stools before recovery (3.5 +/- 0.5 for racecadotril vs. 2.9 +/- 0.4 for loperamide), and the duration of diarrhoea (mean +/- S.E.M.) was similar in both groups (14.9 +/- 2.0 h for racecadotril and 13.7 +/- 2.2 h for loperamide). Both treatments reduced the incidence of associated symptoms and signs during the study, and both were similarly well tolerated. However, more patients on loperamide reported rebound constipation during treatment (18.7% vs. 9.8% with racecadotril). CONCLUSIONS The enkephalinase inhibitor, racecadotril, and the intestinal transit inhibitor, loperamide, were similarly and rapidly effective in resolving the symptoms and associated signs of diarrhoea.
Collapse
Affiliation(s)
- J M Vetel
- Centre Hospitalier, Le Mans, Paris, France.
| | | | | | | |
Collapse
|
19
|
Brun Y, Wang XP, Willemot J, Sevenet T, Demenge P. Experimental study of antidiarrheal activity of Salicairine. Fundam Clin Pharmacol 1998; 12:30-6. [PMID: 9523181 DOI: 10.1111/j.1472-8206.1998.tb00920.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Experimental antidiarrheal activity of a traditionally used medication, Salicairine, was demonstrated in comparison to loperamide by significant inhibition of castor oil-induced diarrhea in mice (increases in hard faeces/total faeces ratio of 38 and 54 and 5 and 54% with respect to controls, at 0.5 and 1 mL/kg and 1 and 2 mg/kg, respectively) and bisacodyl-induced increase in large intestine transit in rats (125 and 280 and 210% with respect to controls, at 0.4 and 2 mL/kg Salicairine and 5 mg/kg loperamide, respectively). Salicairine was able to reduce contractions of isolated rat duodenum induced by barium chloride and acetylcholine, although not completely (that is about 60%) as seen with loperamide. Also, it did not change normal gastrointestinal transit in mice at doses of 0.5 to 1 mL/kg, conversely to loperamide which had a significant effect (decrease of 50%) at 2 mg/kg. Finally, Salicairine at 0.01 mL/mL, like loperamide at 0.2 mg/mL, significantly increased net fluid absorption in rat colon, either in basal conditions (30 and 64% respectively) or after a prostaglandin E1-induced increase in net fluid secretion (41 and 35%, respectively). The antidiarrheal activity of Salicairine is possibly related, at least in part, to an increase in colon net fluid absorption or a decrease in net fluid secretion.
Collapse
Affiliation(s)
- Y Brun
- Laboratoire de Physiologie et Pharmacologie-PCEBM, Faculté de Pharmacie, Université Joseph Fourier, La Tronche, France
| | | | | | | | | |
Collapse
|
20
|
Roques BP, Noble F, Crine P, Fournié-Zaluski MC. Inhibitors of neprilysin: design, pharmacological and clinical applications. Methods Enzymol 1995; 248:263-83. [PMID: 7674926 DOI: 10.1016/0076-6879(95)48019-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- B P Roques
- Département de Pharmacochimie Moléculaire et Structurale, Institut National de la Santé et de la Recherche Medicale, Centre National de la Recherche Scientifique, Université René Descartes, Paris, France
| | | | | | | |
Collapse
|
21
|
Benouali S, Berard H, Roche M. Action of enkephalinase (EC 3.4.24.11) inhibition on the pre- and post-prandial electromyographic patterns of colon in rats. Neuropeptides 1993; 24:299-305. [PMID: 8392143 DOI: 10.1016/0143-4179(93)90019-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Endogenous opioids are an important regulatory factor for the digestive tract and specially for its motility pattern. Enkephalin degradation includes an enkephalinase (EC 3.4.24. 11) and the effects on the colic electromyographic profile of its inhibition by acetorphan has been investigated in the unrestrained rat. Electromyogram consisted of Long Spike Bursts (LSB). In fasted state, they propagated indifferently in both aboral or oral directions from any point of the colon. Feeding privileges LSB which start near the cecal junction and propagated aborally to the distal colon. The acetorphan treatment (A) increases the percentage of LSB propagating aborally on the entire colon in fasted state and (B) reinforces the increased percentage of LSB which propagated down on the entire colon induced by feeding. All the actions of acetorphan on colic motility pattern disappear after inhibition of opioid receptors by naloxone. That may account for involvement of enkephalins in acetorphan properties on the pattern of the colic electrical activity.
Collapse
Affiliation(s)
- S Benouali
- Université de Savoie, Physiologie-Pharmacologie Appliquées, Chambery, France
| | | | | |
Collapse
|
22
|
Roge J, Baumer P, Berard H, Schwartz JC, Lecomte JM. The enkephalinase inhibitor, acetorphan, in acute diarrhoea. A double-blind, controlled clinical trial versus loperamide. Scand J Gastroenterol 1993; 28:352-4. [PMID: 8488368 DOI: 10.3109/00365529309090255] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The antidiarrhoeal properties of acetorphan, an inhibitor of enkephalinase (EC 3.4.24.11) that prevents endogenous enkephalin degradation, and loperamide, a mu opiate receptor agonist, were compared. The double-blind study included 69 patients with acute diarrhoea of presumed infectious origin, allocated at random to two parallel groups. Acetorphan and loperamide were both rapidly and similarly effective, diarrhoea resolving in both cases in nearly 2 days. With acetorphan, however, abdominal distension vanished significantly more rapidly, and reactive constipation was less frequent (8% versus 31% with loperamide). These differences can be accounted for by the distinct mechanisms of antidiarrhoeal activity of the two drugs--that is, primary antitransit effect for loperamide and antisecretory activity for acetorphan.
Collapse
Affiliation(s)
- J Roge
- Policlinic, Kremlin Bicêtre University Hospital Centre, Paris, France
| | | | | | | | | |
Collapse
|
23
|
Cole AT, Hawkey CJ. Acetorphan and diarrhoea. Gut 1993; 34:432. [PMID: 8472999 PMCID: PMC1374163 DOI: 10.1136/gut.34.3.432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
|
24
|
Baumer P, Danquechin Dorval E, Bertrand J, Vetel JM, Schwartz JC, Lecomte JM. Effects of acetorphan, an enkephalinase inhibitor, on experimental and acute diarrhoea. Gut 1992; 33:753-8. [PMID: 1624154 PMCID: PMC1379330 DOI: 10.1136/gut.33.6.753] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Acetorphan is an orally active inhibitor of enkephalinase (EC 3.4.24.11) with antidiarrhoeal activity in rodents apparently through protection of endogenous enkephalins and a purely antisecretory mechanism. Its antidiarrhoeal activity in man was assessed in an experimental model of cathartic induced secretory diarrhoea as well as in acute diarrhoea of presumed infectious origin. In six healthy volunteers receiving castor oil and pretreated with acetorphan or placebo in a crossover controlled trial, the drug significantly decreased the number and weight of stools passed during 24 hours. About 200 outpatients with severe acute diarrhoea (more than five stools per day) were included in a randomised double blind study of acetorphan against placebo. The significant antidiarrhoeal activity of acetorphan was established using a variety of criteria: (i) the duration of both diarrhoea and treatment were diminished; (ii) no acetorphan treated patient withdrew from the study whereas five dropped out because of worsening in the placebo group; (iii) the frequency of symptoms associated with diarrhoea--for example, abdominal pain or distension, nausea and anorexia--remaining after two weeks was nearly halved; (iv) using visual analogue scales acetorphan treatment was found more effective than placebo by both investigators and patients. There was statistically no significant difference between acetorphan and placebo in respect of side effects, particularly constipation, which often accompanies the antidiarrhoeal activity of mu opioid receptor agonists this difference is attributable to the lack of antipropulsive activity of acetorphan in man. The efficacy and tolerance of acetorphan suggest that enkephalinase inhibition may represent a novel therapeutic approach for the symptomatic management of acute secretory diarrhoea without impairing intestinal transit.
Collapse
Affiliation(s)
- P Baumer
- Laboratoire Bioprojet, Marnes la Coquette, France
| | | | | | | | | | | |
Collapse
|
25
|
Bergmann JF, Chaussade S, Couturier D, Baumer P, Schwartz JC, Lecomte JM. Effects of acetorphan, an antidiarrhoeal enkephalinase inhibitor, on oro-caecal and colonic transit times in healthy volunteers. Aliment Pharmacol Ther 1992; 6:305-13. [PMID: 1350927 DOI: 10.1111/j.1365-2036.1992.tb00052.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Acetorphan is a potent enkephalinase inhibitor displaying antidiarrhoeal activity attributable to its intestinal antisecretory action mediated by endogenous enkephalins. The effect of acetorphan on digestive motility was studied in 12 healthy volunteers. Oro-caecal transit time was evaluated using the sulphasalazine/sulphapyridine method and colonic transit times using radiopaque markers. These measurements were successively performed after one week treatment with an antidiarrhoeal dose of acetorphan (100 mg t.d.s.) or placebo. There was no significant modification in transit time linked to acetorphan treatment: total oro-caecal times were 303 +/- 32 min vs. 287 +/- 27 min and colonic transit times 25.8 +/- 5.8 h vs. 31.3 +/- 5.5 h after acetorphan and placebo, respectively (means +/- S.E.M.). There was no significant modification either in right colonic, left colonic or rectosigmoid segmental transit times, or in the mean number of stools. These results, consistent with those from animal studies, confirm that, unlike classical antidiarrhoeal mu opiate receptor agonists, which act by delaying intestinal transit, acetorphan does not affect the transit. Antidiarrhoeal activity not accompanied by a delayed intestinal transit could have beneficial therapeutic consequences in the management of infectious diarrhoea. In addition, we show that the sulphasalazine and radiopaque markers methods can be simultaneously applied in the same study.
Collapse
Affiliation(s)
- J F Bergmann
- Clinique Thérapeutique, Hôpital Lariboisière, Paris, France
| | | | | | | | | | | |
Collapse
|
26
|
Dutriez I, Salès N, Fournié-Zaluski MC, Roques BP. Pre- and post-natal ontogeny of neutral endopeptidase 24-11 ('enkephalinase') studied by in vitro autoradiography in the rat. EXPERIENTIA 1992; 48:290-300. [PMID: 1547865 DOI: 10.1007/bf01930479] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Neutral endopeptidase (NEP, enkephalinase, CALLA) which is present in various neural and non-neural tissues, is able to cleave a variety of regulatory peptides. The distribution of NEP has been studied during rat pre- and post-natal development by autoradiography after in vitro binding of the tritiated inhibitor [3H]HACBO-Gly to whole-body and organ sections. In the central nervous system (CNS), where the presence of NEP has been related to the termination of the action of enkephalins, the external layer of the olfactory bulbs is the only structure prominently labeled before birth. Other CNS structures rich in NEP in the adult, such as the nigrostriatal tract, are progressively labeled after birth. Outside the CNS, the progressive appearance of NEP in the kidney, the lungs and the salivary glands suggests its concomitant involvement in adult physiological functions, including fluid balance control, possibly by cleaving the atrial natriuretic peptide (ANP) and other peptides. On the other hand, transient or enhanced expression of NEP is observed during the development of several organs such as the sensory organs, the heart and the major blood vessels, the intestine, the bones and the genital tubercle. In addition to the still incompletely known physiological functions of the enzyme, the developmental pattern of its expression in several tissues strongly suggests a modulatory role for NEP in the ontogeny of a large number of organs.
Collapse
Affiliation(s)
- I Dutriez
- INSERM U 334, DRIPP, Service hospitalier Frédéric Joliot, Orsay, France
| | | | | | | |
Collapse
|
27
|
Pollard H, Moreau J, Ronco P, Verroust P, Schwartz JC. Immunoautoradiographic localisation of enkephalinase (EC 3.4.24.11) in rat gastrointestinal tract. Neuropeptides 1991; 19:169-78. [PMID: 1716743 DOI: 10.1016/0143-4179(91)90115-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Enkephalinase (EC 3.4.24.11, membrane metalloendopeptidase) is a zinc peptidase expressed by neurons and a variety of epithelial cells, and responsible for the inactivation of enkephalins in brain. Its functions in the gastrointestinal (GI) tract are less well understood although enkephalinase inhibitors were reported to induce a constellation of antisecretory and motor responses. Its localisation in various segments of the rat GI tract was established autoradiographically using a 125I-labelled monoclonal antibody. All along the GI tract, the highest immunoreactivity was found in mucosal layers e.g., in intestinal villi, basal epithelial layers of the oesophagus or gastric cardia, muscularis mucosae of the stomach and large intestine. The immunoreactivity was also high in the stomach submucosae and moderate in the muscularis propria of the caecum. A faint patchy immunoreactivity was also observed in several other layers. This distribution suggests that the membrane peptidase is expressed by enterocytes and a variety of other cells. Its high expression in mucosal layers is consistent with its participation in protein digestion and also in the inactivation of endogenous peptides, particularly the enkephalins, acting at this level to control secretory mechanisms and hydroelectrolytic fluxes. Its presence in submucosal layers may account for some naloxone-reversible motor responses elicited by enkephalinase inhibitors.
Collapse
Affiliation(s)
- H Pollard
- Unité de Neurobiologie et Pharmacologie (U 109) de l'Inserm, Centre Paul Broca, Paris, France
| | | | | | | | | |
Collapse
|
28
|
Sales N, Dutriez I, Maziere B, Ottaviani M, Roques BP. Neutral endopeptidase 24.11 in rat peripheral tissues: comparative localization by 'ex vivo' and 'in vitro' autoradiography. REGULATORY PEPTIDES 1991; 33:209-22. [PMID: 1882086 DOI: 10.1016/0167-0115(91)90215-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The neutral endopeptidase 24.11 (NEP) also called 'enkephalinase' thanks to its inactivation of enkephalins in the brain, was also recently shown to be involved in the degradation of the circulating atrial natriuretic peptide (ANP). Inhibitors of NEP are therefore under clinical trials as new analgesics or antidiarrheal agents, protecting centrally or peripherally released opioid peptides and as novel antidiuretics and anti-hypertensives in prolonging the renal and vascular actions of NEP. It was therefore important from a clinical point of view to investigate the distribution in peripheral tissue of a systemically administered NEP blocker. Different concentrations of the radiolabelled inhibitor [3H]HACBO-Gly have been intravenously injected in rat and the distribution studied using whole-body sections at different times by 'ex vivo' and 'in vitro' autoradiography to investigate differences in tissue accessibility of NEP to a circulating inhibitor. In vivo [3H]HACBO-Gly binding was fully prevented by an excess of unlabelled inhibitor and disappeared rapidly mainly through renal elimination. NEP labelling was prominent in kidney, liver, lung, fat deposits in the neck region, the flat bones of the skull, the mandibula, the vertebrae, the long bones of the limbs, articular cartilages and synoviae. A lower labelling was found in the intestine, the glomeruli and the submaxillary glands. [3H]HACBO-Gly binds also to a limited number of peripheral tissues in which the presence of NEP was yet unknown (bones, parts of adipose tissues. Some tissues, not labelled in vivo, exhibited various degrees of labelling under in vitro conditions (the brain, some portions of the gut, the testes, the prostate). Interestingly, few lobules of the submaxillary glands were much more densely labelled suggesting the possible occurrence of NEP heterogeneity. Except for the brain, the physiological function of NEP in various tissues remains largely unknown, but this ectoenzyme is likely involved in inactivation of regulatory peptides such as: ANP (partially in the kidney), SP in the lung and possibly somatostatin and ANP in bone, ANP in adipose tissue, enkephalin in testes, immune peptidic factors in bone marrow. A part of NEP in bone marrow corresponds probably to the common acute lymphoblastic antigen, CALLA, densely expressed on pre-B cells. Finally, it is important to notice that several tissues containing important concentrations of NEP (brain, testes, prostate, eye, gut, brush border) are inaccessible to the i.v. injected inhibitor thanks to the presence of functional barriers.
Collapse
Affiliation(s)
- N Sales
- U334 INSERM, Hôpital d'Orsay, France
| | | | | | | | | |
Collapse
|
29
|
Abstract
This paper is the tenth installment of our annual review of the research during the past year involving the endogenous opiate system. It covers the nonanalgesia and behavioral studies of the opiate peptides published in 1987. The specific topics this year include stress; tolerance and dependence; eating; drinking; gastrointestinal and renal activity; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; electrical activity; locomotor activity; sex, pregnancy, and development; immunology and cancer; and other behavior.
Collapse
Affiliation(s)
- G A Olson
- Department of Psychology, University of New Orleans, LA 70148
| | | | | |
Collapse
|
30
|
De la Baume S, Schwartz JC. Labelling and exploration of the active site of enkephalinase (EC 3.4.24.11) in kidney membranes with [3H]thiorphan as ligand. Eur J Pharmacol 1988; 149:121-9. [PMID: 3165067 DOI: 10.1016/0014-2999(88)90049-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
[3H]Thiorphan, a potent inhibitor of enkephalinase (EC 3.4.24.11), was used to label the enzyme in membranes from rat kidney cortex an to explore its specificity at the active site. [3H]Thiorphan binding occurred reversibly, with low non-specific binding and to a single class of sites. The dissociation constant, determined by either kinetics or saturation studies was approximately 0.4 nM. The ratio of the maximal velocity of enkephalinase with enkephalins as substrates to the maximal binding of [3H]thiorphan was consistent with the catalytic constant of the enzyme. Enkephalinase inhibitors competed with [3H]thiorphan and had inhibitory constants in agreement with the corresponding values derived from measurement of the enzyme catalytic activity, whereas inhibitors of other metallopeptidases were ineffective. The inhibitory potencies of a series of systematically varied oligopeptides regarding [3H]thiorphan binding and enkephalinase activity were also highly correlated. Structure-activity relationships among competitors indicated that the main subsites of enkephalinase are: (1) the hydrophobic pocket in P'1, the requirements of which are best satisfied by aromatic amino acid side chain residues (2) the P'2 subsite, the requirements of which are best satisfied by amino acids with a short, uncharged side chain and a free terminal carboxyl group. This novel binding assay should facilitate the exploration of the active site of enkephalinase and the development of new inhibitors.
Collapse
Affiliation(s)
- S De la Baume
- Unité 109 de Neurobiologie et Pharmacologie, Centre Paul Broca de l'INSERM, Paris, France
| | | |
Collapse
|
31
|
Chapter 2. Analgesics. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 1988. [DOI: 10.1016/s0065-7743(08)60830-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
|