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Merecz K, Hirsa M, Biniszewska O, Fichna J, Tarasiuk A. An overview of 5-HT 3 receptor antagonists as a treatment option for irritable bowel syndrome with diarrhea. Expert Opin Pharmacother 2023:1-10. [PMID: 37173833 DOI: 10.1080/14656566.2023.2214314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
INTRODUCTION Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by abdominal pain, discomfort, and altered bowel habits, which affects the quality of life of approximately 10% of the worldwide population. IBS is classified into three types: IBS-D (diarrhea-predominant), IBS-C (constipation-predominant), and mixed or alternating IBS (IBS-M). Among potential interventions for IBS-D, the antagonism of the serotonin 5-HT3 receptor has recently emerged as an effective treatment option. Serotonin (5-HT) is a neurotransmitter and an immunoregulatory factor which plays a key role in physiological and pathological processes of the human body, having an impact on intestinal motility and gland secretion, which assist in maintaining intestinal homeostasis. AREAS COVERED In this paper, the concept of 5-HT3 antagonists in the treatment of individuals with IBS-D is discussed, with particular focus on mechanism of action and pre-clinical and clinical data. This study is based on pertinent papers that were retrieved by a selective search using relevant keywords in PubMed and ScienceDirect databases. EXPERT OPINION Recent clinical trial data has confirmed beyond doubt the value of 5-HT3 antagonists. As for future directions, weak partial 5-HT3 receptor agonism appears to be an appealing alternative to a silent antagonist for the treatment of IBS-D.
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Affiliation(s)
- Karolina Merecz
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Mazowiecka, Poland
| | - Mikołaj Hirsa
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Mazowiecka, Poland
| | - Olga Biniszewska
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Mazowiecka, Poland
| | - Jakub Fichna
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Mazowiecka, Poland
| | - Aleksandra Tarasiuk
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Mazowiecka, Poland
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Oi Yan Chan J, Moullet M, Williamson B, Arends RH, Pilla Reddy V. Harnessing Clinical Trial and Real-World Data Towards an Understanding of Sex Effects on Drug Pharmacokinetics, Pharmacodynamics and Efficacy. Front Pharmacol 2022; 13:874606. [PMID: 35734405 PMCID: PMC9207260 DOI: 10.3389/fphar.2022.874606] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 05/09/2022] [Indexed: 11/21/2022] Open
Abstract
Increasing clinical data on sex-related differences in drug efficacy and toxicity has highlighted the importance of understanding the impact of sex on drug pharmacokinetics and pharmacodynamics. Intrinsic differences between males and females, such as different CYP enzyme activity, drug transporter expression or levels of sex hormones can all contribute to different responses to medications. However, most studies do not include sex-specific investigations, leading to lack of sex-disaggregated pharmacokinetic and pharmacodynamic data. Based available literature, the potential influence of sex on exposure-response relationship has not been fully explored for many drugs used in clinical practice, though population-based pharmacokinetic/pharmacodynamic modelling is well-placed to explore this effect. The aim of this review is to highlight existing knowledge gaps regarding the effect of sex on clinical outcomes, thereby proposing future research direction for the drugs with significant sex differences. Based on evaluated drugs encompassing all therapeutic areas, 25 drugs demonstrated a clinically meaningful sex differences in drug exposure (characterised by ≥ 50% change in drug exposure) and this altered PK was correlated with differential response.
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Affiliation(s)
- Joyce Oi Yan Chan
- Clinical Pharmacology and Safety Sciences, Biopharmaceuticals R&D, AstraZeneca, Cambridge, United Kingdom
| | - Marie Moullet
- Clinical Pharmacology and Safety Sciences, Biopharmaceuticals R&D, AstraZeneca, Cambridge, United Kingdom
| | | | - Rosalinda H. Arends
- Clinical Pharmacology and Safety Sciences, Biopharmaceuticals R&D, AstraZeneca, Cambridge, United Kingdom
- Clinical Pharmacology and Safety Sciences, Biopharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, United States
| | - Venkatesh Pilla Reddy
- Clinical Pharmacology and Safety Sciences, Biopharmaceuticals R&D, AstraZeneca, Cambridge, United Kingdom
- *Correspondence: Venkatesh Pilla Reddy,
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Tait C, Sayuk GS. The Brain-Gut-Microbiotal Axis: A framework for understanding functional GI illness and their therapeutic interventions. Eur J Intern Med 2021; 84:1-9. [PMID: 33423906 DOI: 10.1016/j.ejim.2020.12.023] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 12/05/2020] [Accepted: 12/09/2020] [Indexed: 12/18/2022]
Abstract
Functional gastrointestinal disorders (FGIDs), characterized by chronic abdominal complaints without a structural or biochemical cause, are common diseases that are frequently encountered by specialists in internal medicine. Collectively, irritable bowel syndrome (IBS) and functional dyspepsia are estimated to affect up to 22% of the population, and are often associated with additional somatic and pain complaints, all without an obvious structural source [1,2]. An appreciation of the current understanding of the mechanistic basis for these disorders is key to developing treatment goals and optimization of patient management strategies. In recent years, the brain-gut axis increasingly has been recognized as a central factor in the experience of functional abdominal pain disorders, including the most recent Rome IV guidelines which identify FGIDs as disorders of gut-brain interaction [3]. The brain-gut axis (BGA), simply defined, is a complex network of bidirectional communication between the central and enteric nervous systems. This axis broadly includes all the systems involved with communication between the GI tract and central nervous system (CNS), with principle inputs into this network occurring between the CNS, enteric nervous system (ENS), and autonomic nervous systems (ANS), but also includes interfaces with numerous other factors, including endocrine hormones and immune effector cells as well as interactions with the gut microbiota. Perturbances to this system have been found to play a critical role in the development of visceral hypersensitivity, bowel dysregulation, and mood. This review will summarize the principle processes involved in the neurologic and biologic function of the brain-gut axis, our current understanding of its role in functional GI disorders, and potential targets for therapeutic intervention.
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Affiliation(s)
- Christopher Tait
- Department of Medicine, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Gregory S Sayuk
- Department of Medicine, Washington University in St. Louis School of Medicine, St. Louis, Missouri; Department of Psychiatry at Washington University in St. Louis School of Medicine, St. Louis, Missouri; Gastroenterology Section, St. Louis Veterans Affairs Medical Center, St. Louis, Missouri.
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Kano M, Dupont P, Aziz Q, Fukudo S. Understanding Neurogastroenterology From Neuroimaging Perspective: A Comprehensive Review of Functional and Structural Brain Imaging in Functional Gastrointestinal Disorders. J Neurogastroenterol Motil 2018; 24:512-527. [PMID: 30041284 PMCID: PMC6175554 DOI: 10.5056/jnm18072] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 05/21/2018] [Indexed: 12/13/2022] Open
Abstract
This review provides a comprehensive overview of brain imaging studies of the brain-gut interaction in functional gastrointestinal disorders (FGIDs). Functional neuroimaging studies during gut stimulation have shown enhanced brain responses in regions related to sensory processing of the homeostatic condition of the gut (homeostatic afferent) and responses to salience stimuli (salience network), as well as increased and decreased brain activity in the emotional response areas and reduced activation in areas associated with the top-down modulation of visceral afferent signals. Altered central regulation of the endocrine and autonomic nervous responses, the key mediators of the brain-gut axis, has been demonstrated. Studies using resting-state functional magnetic resonance imaging reported abnormal local and global connectivity in the areas related to pain processing and the default mode network (a physiological baseline of brain activity at rest associated with self-awareness and memory) in FGIDs. Structural imaging with brain morphometry and diffusion imaging demonstrated altered gray- and white-matter structures in areas that also showed changes in functional imaging studies, although this requires replication. Molecular imaging by magnetic resonance spectroscopy and positron emission tomography in FGIDs remains relatively sparse. Progress using analytical methods such as machine learning algorithms may shift neuroimaging studies from brain mapping to predicting clinical outcomes. Because several factors contribute to the pathophysiology of FGIDs and because its population is quite heterogeneous, a new model is needed in future studies to assess the importance of the factors and brain functions that are responsible for an optimal homeostatic state.
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Affiliation(s)
- Michiko Kano
- Frontier Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University, Sendai,
Japan
- Behavioral Medicine, Graduate School of Medicine, Tohoku University, Sendai,
Japan
- Psychosomatic Medicine, Tohoku University Hospital, Sendai,
Japan
| | | | - Qasim Aziz
- Center for Digestive Diseases, Wingate Institute of Neurogastroenterology, Barts and the London School of Medicine and Dentistry, Queen Mary College, University of London,
UK
| | - Shin Fukudo
- Behavioral Medicine, Graduate School of Medicine, Tohoku University, Sendai,
Japan
- Psychosomatic Medicine, Tohoku University Hospital, Sendai,
Japan
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Bellucci F, Buéno L, Bugianesi R, Crea A, D'Aranno V, Meini S, Santicioli P, Tramontana M, Maggi CA. Gender-related differential effect of tachykinin NK2 receptor-mediated visceral hyperalgesia in guinea pig colon. Br J Pharmacol 2016; 173:1329-38. [PMID: 26758701 DOI: 10.1111/bph.13427] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 12/21/2015] [Accepted: 01/06/2016] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND AND PURPOSE The tachykinin NK2 receptor antagonist ibodutant is under Phase III clinical investigation to treat female patients with irritable bowel syndrome. The aim of this study was to investigate the NK2 receptor-related gender specificity in a model of colitis. EXPERIMENTAL APPROACH Colitis was induced by rectal instillation of 2,4,6-trinitrobenzenesulfonic acid (TNBS, 0.5 mL, 30 mg·mL(-1) in 30% ethanol) in female and male guinea pigs. Electromyographic recording of the responses to colorectal distension (CRD) was made 3 days later. Ibodutant (0.33 , 0.65, 1.9 and 6.5 mg·kg(-1) ) was given s.c., 30 min before CRD. Release of neurokinin A and substance P from isolated mucosal and smooth muscle tissues following treatment with KCl (80 mM) or capsaicin (10 μM) was measured by EIA. Plasma pharmacokinetics of ibodutant following a single s.c. administration (0.73 or 2.1 mg·kg(-1) ) were measured over 24 h. KEY RESULTS Ibodutant did not affect abdominal contractions in control animals. After TNBS-induced colitis, ibodutant prevented the increased visceral hypersensitivity to CRD in females, at lower doses than in males. Ibodutant pharmacokinetics did not differ between females and males. Tachykinins release was greater in smooth muscle than in mucosal samples. Capsaicin-stimulated release of tachykinins from inflamed mucosal samples from females was significantly lower than in males. CONCLUSIONS AND IMPLICATIONS Ibodutant prevented abdominal nociception in a model of visceral hypersensitivity in guinea pigs with a greater efficacy in females than in males. Our results highlight a gender-related difference in colonic visceral hypersensitivity and mucosal nerve activation.
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Affiliation(s)
- F Bellucci
- Pharmacology Department, Menarini Ricerche S.p.A., Florence, Italy
| | - L Buéno
- Neurogastroenterology & Nutrition Department INRA/ESAP, Toulouse, France
| | - R Bugianesi
- Pharmacokinetics Department, Menarini Ricerche S.p.A., Rome, Italy
| | - A Crea
- Pharmacokinetics Department, Menarini Ricerche S.p.A., Rome, Italy
| | - V D'Aranno
- Pharmacokinetics Department, Menarini Ricerche S.p.A., Rome, Italy
| | - S Meini
- Pharmacology Department, Menarini Ricerche S.p.A., Florence, Italy
| | - P Santicioli
- Pharmacology Department, Menarini Ricerche S.p.A., Florence, Italy
| | - M Tramontana
- Pharmacology Department, Menarini Ricerche S.p.A., Florence, Italy
| | - C A Maggi
- Pharmacology Department, Menarini Ricerche S.p.A., Florence, Italy
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Sayuk GS, Gyawali CP. Irritable bowel syndrome: modern concepts and management options. Am J Med 2015; 128:817-27. [PMID: 25731138 DOI: 10.1016/j.amjmed.2015.01.036] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Revised: 01/17/2015] [Accepted: 01/20/2015] [Indexed: 12/14/2022]
Abstract
Irritable bowel syndrome is the most common functional gastrointestinal disorder, manifesting as abdominal pain/discomfort and altered bowel function. Despite affecting as many as 20% of adults, a lack of understanding of etiopathogenesis and evaluation strategies results in diagnostic uncertainty, and in turn frustration of both the physician and the patient. This review summarizes the current literature on the diagnosis and management of irritable bowel syndrome, with attention to evidence-based approaches. A 4-step treatment strategy that has been used successfully in our tertiary referral practice is presented and should lead to successful therapeutic outcomes in the majority of patients with irritable bowel syndrome.
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Affiliation(s)
- Gregory S Sayuk
- Division of Gastroenterology, Washington University School of Medicine, St Louis, Mo; Department of Psychiatry, Washington University School of Medicine, St Louis, Mo; John Cochran Veteran Affairs Medical Center, St Louis, Mo
| | - C Prakash Gyawali
- Division of Gastroenterology, Washington University School of Medicine, St Louis, Mo.
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Abstract
PURPOSE OF REVIEW Irritable bowel syndrome (IBS) and chronic idiopathic constipation (CIC) are highly prevalent medical conditions that reduce quality of life and represent a substantial economic burden on healthcare cost. Until recently, no specific treatment options were available. This review will provide an update of the most recent randomized clinical trials data showing efficacy and safety of novel, targeted treatment modalities in IBS and CIC with gastrointestinal receptor and ion channel agonists. RECENT FINDINGS Recent discoveries of peptides and small molecules targeting gastrointestinal receptors and ion channels resulted in novel, specific pharmacological therapies of IBS and CIC. The bicyclical fatty acid lubiprostone and the synthetic 14-amino acid peptide linaclotide were identified to selectively activate a Chloride Channel-2 and the Guanylin Cyclase-C receptor, respectively, and demonstrate efficacy in the treatment of IBS with constipation and CIC. SUMMARY Novel molecules including the bicyclical fatty acid lubiprostone and the synthetic 14-amino acid peptide linaclotide represent new treatment modalities for IBS with constipation and CIC with proven efficacy and acceptable side-effect profiles.
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Affiliation(s)
- Supriya Rao
- Boston University School of Medicine, Section of Gastroenterology, Boston, Massachusetts, USA
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ITO T, SAKAKIBARA R, SHIMIZU E, KISHI M, TSUYUZAKI Y, TATENO F, UCHIYAMA T, YAMAMOTO T. Is Major Depression a Risk for Bladder, Bowel, and Sexual Dysfunction? Low Urin Tract Symptoms 2012; 4:87-95. [DOI: 10.1111/j.1757-5672.2011.00140.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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9
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Heitkemper MM, Chang L. Do fluctuations in ovarian hormones affect gastrointestinal symptoms in women with irritable bowel syndrome? ACTA ACUST UNITED AC 2010; 6 Suppl 2:152-67. [PMID: 19406367 DOI: 10.1016/j.genm.2009.03.004] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2008] [Indexed: 02/07/2023]
Abstract
BACKGROUND An increase in gastrointestinal (GI) symptoms, including bowel discomfort, abdominal pain/discomfort, bloating, and alterations in bowel patterns, has been reported during premenses and menses menstrual cycle phases and the perimenopause period in women with and without irritable bowel syndrome (IBS). OBJECTIVE This article reviews the literature related to one possible physiological mechanism-declining or low ovarian hormone levels--that may underlie the occurrence or exacerbations of abdominal pain/discomfort at times of low ovarian hormones (menses, menopause) in women with or without IBS. METHODS To identify English-only review and data-based articles, PubMed was searched between January 1980 and September 2008 using the following terms: irritable bowel syndrome, functional gastrointestinal disorders, gastrointestinal motility, immune, pain, hyperalgesia, menstrual cycle, menopause, pregnancy, estrogen, estradiol (E(2)), and progesterone. Studies in animals and in humans were included; drug trials were excluded. RESULTS From our review of the literature, 18 papers were identified that were related either to the mechanisms accounting for menstrual cycle fluctuations (n = 12) or to the impact of menopausal status on symptoms of IBS (n = 6). One study reported that visceral pain sensitivity was significantly higher during menses than at other menstrual cycle phases in women with IBS (P < 0.05). Other menstrual cycle phase-linked symptoms, dysmenorrheal symptoms (cramping pain) in particular, were more intense in women with IBS. Animal studies have shed some light on the relationship of ovarian hormones to GI sensorimotor function. CONCLUSION The increase in GI symptoms around the time of menses and early menopause occurs at times of declining or low ovarian hormones, suggesting that estrogen and progesterone withdrawal may contribute either directly or indirectly. This review highlights the need for confirmatory preclinical and clinical studies to unravel the role of ovarian hormones in women with IBS.
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Affiliation(s)
- Margaret M Heitkemper
- Department of Biobehavioral Nursing and Health Systems, University of Washington, Seattle, Washington 98125-7266, USA.
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Gaman A, Bucur MC, Kuo B. Therapeutic advances in functional gastrointestinal disease: irritable bowel syndrome. Therap Adv Gastroenterol 2009; 2:169-181. [PMID: 19936327 PMCID: PMC2779541 DOI: 10.1177/1756283x08103656] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Reported prevalence rates of irritable bowel syndrome (IBS) are between 8% to 20% in the US general population with an average medical expenditure of US$1.35 billion direct and US$205 million indirect costs. Current pathophysiologic theories are based on abnormalities of both the brain and gut, thus setting a new stage for current and future therapeutic approaches. There are numerous treatment options in IBS acting centrally and peripherally by influencing motility and visceral sensitivity. Clinical evidence is variable; however, newer emerging treatments are being evaluated using better-designed clinical trials. Accurate assessment of IBS drug efficacy is still hampered by heterogeneity of the IBS population. Novel methods such as pharmacogenomics or brain imaging may be helpful in the future to better understand and characterize IBS patient subtypes, and this in turn will lead to more specific and efficient therapeutic options. Patient subpopulation measurement of side effects is also a clinical challenge and further understanding could improve treatment efficacy enhancing the patient compliance.
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Affiliation(s)
- Alexandru Gaman
- Massachusetts General Hospital, Gastrointestinal Unit, Harvard Medical
School, Boston, MA, USA
| | - Maria Cristina Bucur
- Massachusetts General Hospital, Gastrointestinal Unit, Harvard Medical
School, Boston, MA, USA
| | - Braden Kuo
- Massachusetts General Hospital, Gastrointestinal Unit, Harvard Medical
School, Boston, MA, USA
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11
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Identification of patients with non-d, non-C irritable bowel syndrome and treatment with renzapride: an exploratory, multicenter, randomized, double-blind, placebo-controlled clinical trial. Dig Dis Sci 2008; 53:3191-200. [PMID: 18465239 DOI: 10.1007/s10620-008-0295-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Accepted: 04/10/2008] [Indexed: 12/12/2022]
Abstract
This was an exploratory study of renzapride in 168 male and female patients with non-D, non-C irritable bowel syndrome (IBS). Patients were randomized to placebo or renzapride (1, 2, or 4 mg/day) for 8 weeks. The primary efficacy variable was patient-reported satisfactory relief of IBS symptoms. Secondary variables included relief of abdominal pain/discomfort. The proportion of patients reporting satisfactory relief of their IBS symptoms for at least 50% of the time did not differ significantly from those on placebo. However, post hoc analysis in women showed differences in responder rate on renzapride versus placebo of 18.2% (95% CI -5% to 42%; P = 0.066) during weeks 1-4 and 6% (95% CI -21% to 33%; P = 0.339) during weeks 5-8. Renzapride was well tolerated and most adverse events were mild to moderate in intensity. Further studies are warranted to determine whether renzapride is beneficial in this patient population.
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12
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Scarpellini E, Tack J. Renzapride: a new drug for the treatment of constipation in the irritable bowel syndrome. Expert Opin Investig Drugs 2008; 17:1663-70. [DOI: 10.1517/13543784.17.11.1663] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Zeng F, Liu XG, Li XZ, Liang FR. Research progress in brain function imaging of irritable bowel syndrome. Shijie Huaren Xiaohua Zazhi 2008; 16:1435-1439. [DOI: 10.11569/wcjd.v16.i13.1435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Along with the development of nerve imaging, brain function imaging technique is gradually used in the research of functional gastrointestinal disorders (FGID), and it provides a new method for further investigation of the relationship between brain cortex function, gut function and FGID, as well as the relationship between brain and digestive tract. This review focuses on the major progress in the overseas study of irritable bowel syndrome using positron emission tomography and functional magnetic resonance imaging, the problems and application prospect.
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George AM, Meyers NL, Hickling RI. Clinical trial: renzapride therapy for constipation-predominant irritable bowel syndrome--multicentre, randomized, placebo-controlled, double-blind study in primary healthcare setting. Aliment Pharmacol Ther 2008; 27:830-7. [PMID: 18284648 DOI: 10.1111/j.1365-2036.2008.03649.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Relatively few pharmacological treatment options are available for treating patients with irritable bowel syndrome. New and effective medicines are urgently required. AIM To identify an appropriate dosage of renzapride (a 5-HT(4) receptor full agonist/5-HT(3) receptor antagonist) to treat abdominal pain/discomfort in patients with constipation-predominant irritable bowel syndrome. METHODS In this randomized, placebo-controlled, phase IIb study in the primary care setting, men and women were randomized to placebo or renzapride (1, 2 or 4 mg/day) for 12 weeks. The primary outcome measure was patient self-assessed relief of abdominal pain/discomfort during weeks 5-12. Secondary efficacy measures included patients' assessment of their bowel habits, stool consistency and quality of life. RESULTS Although there were no statistically significant differences between renzapride and placebo for relief from abdominal pain/discomfort, responder rates in the renzapride treatment groups increased dose dependently, with the 4 mg/day group being consistently numerically greater than placebo. Importantly, a larger numerical treatment difference vs. placebo was observed in women (8% and 12% respectively). Statistically significant improvements in bowel movement frequency and stool consistency were observed in the 4 mg/day group relative to placebo. Renzapride was well tolerated at all doses. CONCLUSIONS This study confirms the gastrointestinal prokinetic effects of renzparide. The data also suggested a potentially beneficial effect on abdominal pain/discomfort in women with constipation-predominant irritable bowel syndrome.
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15
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Ouyang A, Wrzos HF. Contribution of gender to pathophysiology and clinical presentation of IBS: should management be different in women? Am J Gastroenterol 2006; 101:S602-9. [PMID: 17177863 DOI: 10.1111/j.1572-0241.2006.00975.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The irritable bowel syndrome (IBS) is found more commonly in women than men. It is more prevalent in patients with chronic fatigue syndrome, fibromyalgia, and chronic pelvic pain, all syndromes characterized by pain and found predominantly in women. This article reviews evidence for a role of biological sex factors and gender on the pathways mediating visceral pain. The effect of gonadal hormones on gastrointestinal motility and the sensory afferent pathway and central processing of visceral stimuli and the contribution of gender role to the clinical presentation are discussed. Although differences in responses to treatment modalities between genders exist, the approach to IBS patients in both genders is quite similar. Nevertheless, a special attention to gender role and stress-related factors should be addressed. New developments in research, outlined in the paper, might bring more gender-specific treatments in the future.
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Affiliation(s)
- Ann Ouyang
- Division of Gastroenterology and Hepatology, The Milton S. Hershey Medical Center, College of Medicine, Pennsylvania State University, Hershey, Pennsylvania 17033, USA
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16
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Sakai Y, Nishikawa M, Leyton M, Benkelfat C, Young SN, Diksic M. Cortical trapping of alpha-[(11)C]methyl-l-tryptophan, an index of serotonin synthesis, is lower in females than males. Neuroimage 2006; 33:815-24. [PMID: 16996279 DOI: 10.1016/j.neuroimage.2006.08.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Revised: 06/27/2006] [Accepted: 08/04/2006] [Indexed: 10/24/2022] Open
Abstract
One neural system that may exhibit gender differences is serotonin (5-HT), a neurotransmitter implicated in the regulation of mood, cognitive processes, and impulse-control. However, most of the available evidence of gender-related differences in this system has been indirect and at times contradictory. The objective of the present study was to follow up on preliminary evidence that there are gender differences in brain regional 5-HT synthesis, as measured by trapping of alpha-[(11)C]methyl-l-tryptophan (alpha-[(11)C]MTrp). Sixty-minute dynamic scans were performed in healthy volunteers, 28 women and 31 men. Functional images of the brain trapping constant, used as a proxy for 5-HT synthesis, which correlate in the rat brain with tryptophan's conversion into 5-HT, were transferred to the standardized 3D space. The voxel based comparison was performed by Statistical Parametric Mapping with proportional normalization. There was lower normalized alpha-[(11)C]MTrp trapping in females than males throughout much of the cerebral cortex, including the left middle frontal gyrus, the bilateral inferior frontal gyrus, the bilateral precentral gyrus, the left supramarginal gyrus, the bilateral inferior parietal lobule, the left superior temporal gyrus, the bilateral posterior cingulate gyrus, and the bilateral precuneus. There were no regions in which the normalized trapping was significantly higher in females than in males. Gender differences in sub-cortical sites were not found. Women, compared to men, may have lower rates of this tracer trapping, used as a proxy for 5-HT synthesis, throughout much of the cerebral cortex which is likely related to differences in 5-HT synthesis because relative differences in the normalized trapping should be the same as those in 5-HT synthesis. These differences may be related, at least in part, to previously suggested gender differences in affect, cognitive processes, and susceptibility to 5-HT-related neuropsychiatric and neurological disorders.
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Affiliation(s)
- Y Sakai
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University St., Montreal, Canada QC H3A 2B4
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Watanabe A, Nakai A, Tohyama Y, Nguyen KQ, Diksic M. Effects of anpirtoline on regional serotonin synthesis in the rat brain: an autoradiographic study. Nucl Med Biol 2006; 33:325-32. [PMID: 16631081 DOI: 10.1016/j.nucmedbio.2005.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2005] [Revised: 08/09/2005] [Accepted: 08/09/2005] [Indexed: 11/23/2022]
Abstract
Anpirtoline has been described as an agonist at 5-HT1B receptors with a relatively high potency. It also acts as an agonist at 5-HT1A receptors, but has a lower potency than at the 5-HT1B sites. There is very little known about the mechanism by which anpirtoline influences regional 5-HT synthesis. The aim of the present study was to investigate the effects of acutely and chronically administered anpirtoline on 5-HT synthesis in the rat brain using the autoradiographic alpha-[14C]methyl-L-tryptophan method. In the acute study, anpirtoline (2.0 mg/kg) was administered intraperitoneally 30 min before the tracer injection. The control rats were injected with the same volume of saline. In the chronic study, anpirtoline (2 mg/kg per day) was injected subcutaneously in saline once a day for 10 days. There were no significant differences between the plasma-free and total tryptophan concentrations between the anpirtoline treatment and the respective control groups. In the acute experiment, 5-HT synthesis rates in all of the brain areas investigated were significantly decreased by anpirtoline when compared to the saline-treated group. In the chronic anpirtoline experiment, 5-HT synthesis rates of almost all of the projection areas, as well as the raphe nuclei, were normalized or had a tendency to be normalized. These results suggest that it is likely that the terminal 5-HT1B receptors are involved in the regulation of 5-HT synthesis in the projection areas and that 5-HT synthesis, in the raphe, is likely influenced by anpirtoline's 5-HT1A and/or 5-HT1B agonistic properties.
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Affiliation(s)
- Arata Watanabe
- Cone Neurological Research Laboratory, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada H3A 2B4
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Abstract
Functional brain imaging has greatly enhanced the ability to investigate brain-gut interactions and to assess the central nervous system role on visceral pain perception. The results of studies using brain imaging in irritable bowel syndrome (IBS) have demonstrated differences in brain activation between patients with IBS and healthy controls. In addition, the more recent studies are starting to shed light on pathophysiological mechanisms that underlie the generation of functional gastrointestinal (GI) symptoms as well as the response to treatment. These studies highlight the potential of functional brain imaging to become an important and exciting investigative tool in research of functional GI disorders. However, the multifactorial, multideterminant nature of these disorders, the current limitations in the understanding of the pathophysiology of the disorders, and the heterogeneous patient population make brain imaging research in this field difficult and require caution in the interpretation of the data. The continued development of brain imaging techniques provides not only exciting opportunities but also significant challenges to the field. This article focuses on brain imaging research in functional GI disorders. It describes some of the recent developments in the use of brain imaging in research of the brain-gut axis and provides an overview of the current data.
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Affiliation(s)
- Yehuda Ringel
- UNC School of Medicine, Department of Medicine, Division of Digestive and Liver Diseases, Chapel Hill, NC 27599-7080, USA.
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