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Pergolizzi S, Alesci A, Centofanti A, Aragona M, Pallio S, Magaudda L, Cutroneo G, Lauriano ER. Role of Serotonin in the Maintenance of Inflammatory State in Crohn’s Disease. Biomedicines 2022; 10:biomedicines10040765. [PMID: 35453516 PMCID: PMC9030789 DOI: 10.3390/biomedicines10040765] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 02/05/2023] Open
Abstract
Crohn’s disease (CD) is a chronic intestinal inflammation considered to be a major entity of inflammatory bowel diseases (IBDs), affecting different segments of the whole gastrointestinal tract. Peripheral serotonin (5-HT), a bioactive amine predominantly produced by gut enterochromaffin cells (ECs), is crucial in gastrointestinal functions, including motility, sensitivity, secretion, and the inflammatory response. These actions are mediated by a large family of serotonin receptors and specialized serotonin transporter (SERT) located on a variety of cell types in the gut. Several studies indicate that intestinal 5-HT signaling is altered in patients with inflammatory bowel disease. Paraformaldehyde-fixed intestinal tissues, obtained from fifteen patients with Crohn’s disease were analyzed by immunostaining for serotonin, Langerin/CD207, and alpha-Smooth Muscle Actin (α-SMA). As controls, unaffected (normal) intestinal specimens of seven individuals were investigated. This study aimed to show the expression of serotonin in dendritic cells (DCs) and myofibroblast which have been characterized with Langerin/CD207 and α-SMA, respectively; furthermore, for the first time, we have found the presence of serotonin in goblet cells. Our results show the correlation between different types of intestinal cells in the maintenance of the inflammatory state in CD linked to the recall of myofibroblasts.
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Affiliation(s)
- Simona Pergolizzi
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy;
- Correspondence: (S.P.); (A.A.); (A.C.)
| | - Alessio Alesci
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy;
- Correspondence: (S.P.); (A.A.); (A.C.)
| | - Antonio Centofanti
- Department of Biomedical and Dental Sciences and Morphofunctional Images, University of Messina, 98125 Messina, Italy; (L.M.); (G.C.)
- Correspondence: (S.P.); (A.A.); (A.C.)
| | - Marialuisa Aragona
- Department of Veterinary Sciences, University of Messina, Polo Universitario dell’Annunziata, 98168 Messina, Italy;
| | - Socrate Pallio
- Department of Clinical and Experimental Medicine, University of Messina, 98147 Messina, Italy;
| | - Ludovico Magaudda
- Department of Biomedical and Dental Sciences and Morphofunctional Images, University of Messina, 98125 Messina, Italy; (L.M.); (G.C.)
| | - Giuseppina Cutroneo
- Department of Biomedical and Dental Sciences and Morphofunctional Images, University of Messina, 98125 Messina, Italy; (L.M.); (G.C.)
| | - Eugenia Rita Lauriano
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy;
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Chiocchetti R, Galiazzo G, Giancola F, Tagliavia C, Bernardini C, Forni M, Pietra M. Localization of the Serotonin Transporter in the Dog Intestine and Comparison to the Rat and Human Intestines. Front Vet Sci 2022; 8:802479. [PMID: 35071391 PMCID: PMC8766808 DOI: 10.3389/fvets.2021.802479] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 12/10/2021] [Indexed: 12/23/2022] Open
Abstract
Serotonin is crucial in gastrointestinal functions, including motility, sensitivity, secretion, and the inflammatory response. The serotonin transporter (SERT), responsible for serotonin reuptake and signaling termination, plays a prominent role in gastrointestinal physiology, representing a promising therapeutic target in digestive disorders. Serotonin transporter expression has been poorly investigated in veterinary medicine, under both healthy and pathological conditions, including canine chronic enteropathy, in which the serotonin metabolism seems to be altered. The aim of the present study was to determine the distribution of SERT immunoreactivity (SERT-IR) in the dog intestine and to compare the findings with those obtained in the rat and human intestines. Serotonin transporter-IR was observed in canine enterocytes, enteric neurons, lamina propria cells and the tunica muscularis. Data obtained in dogs were consistent with those obtained in rats and humans. Since the majority of the serotonin produced by the body is synthesized in the gastrointestinal tract, SERT-expressing cells may exert a role in the mechanism of serotonin reuptake.
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Affiliation(s)
- Roberto Chiocchetti
- Department of Veterinary Medical Sciences (UNI EN ISO 9001:2008), University of Bologna, Ozzano dell'Emilia, Italy
| | - Giorgia Galiazzo
- Department of Veterinary Medical Sciences (UNI EN ISO 9001:2008), University of Bologna, Ozzano dell'Emilia, Italy
| | - Fiorella Giancola
- Department of Veterinary Medical Sciences (UNI EN ISO 9001:2008), University of Bologna, Ozzano dell'Emilia, Italy
| | - Claudio Tagliavia
- Department of Veterinary Medical Sciences (UNI EN ISO 9001:2008), University of Bologna, Ozzano dell'Emilia, Italy
| | - Chiara Bernardini
- Department of Veterinary Medical Sciences (UNI EN ISO 9001:2008), University of Bologna, Ozzano dell'Emilia, Italy
| | - Monica Forni
- Department of Veterinary Medical Sciences (UNI EN ISO 9001:2008), University of Bologna, Ozzano dell'Emilia, Italy
| | - Marco Pietra
- Department of Veterinary Medical Sciences (UNI EN ISO 9001:2008), University of Bologna, Ozzano dell'Emilia, Italy
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Grasberger H, Chang L, Shih W, Presson AP, Sayuk GS, Newberry RD, Karagiannides I, Pothoulakis C, Mayer E, Merchant JL. Identification of a functional TPH1 polymorphism associated with irritable bowel syndrome bowel habit subtypes. Am J Gastroenterol 2013; 108:1766-74. [PMID: 24060757 PMCID: PMC4067697 DOI: 10.1038/ajg.2013.304] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 08/06/2013] [Indexed: 02/06/2023]
Abstract
OBJECTIVES Alterations in 5-hydroxytryptamine (5-HT) signaling have been implicated as a factor contributing to the altered bowel habit of irritable bowel syndrome (IBS) patients. Tryptophan hydroxylase 1 (TPH1) is the rate-limiting enzyme in enterochromaffin cell 5-HT biosynthesis. We hypothesized that genetic variants affecting TPH1 gene expression might alter intestinal 5-HT bioavailability and subsequently the propensity for distinct bowel habit subtypes in IBS. In this study, we assessed the only common TPH1 proximal promoter variant (-347C/A; rs7130929) and its association with bowel habit predominance in IBS. METHODS Electrophoretic mobility shift assays were performed to assess whether the -347C/A-allele variant affects the DNA binding of nuclear factors. Genotype distribution was determined for 422 IBS patients subtyped using the Rome III criteria and for 495 healthy controls recruited from two university medical centers. Association with bowel habit was tested using a multinomial logistic regression model controlling for race, anxiety, depression, and study site. RESULTS Early growth response factor 1 (EGR-1) bound with higher affinity to a site comprising the minor A-allele of single-nucleotide polymorphism (SNP) -347C/A. TPH1 genotype frequencies did not differ between IBS patients and controls overall. The CC genotype was more prevalent in the IBS-D subtype (47%) than in the IBS-C (25%) and IBS-M (37%) subtypes (P=0.039) after adjusting for race and other covariates. Colonic biopsies from a small cohort of IBS patients from one center were tested for higher TPH1 mRNA expression in samples with CC compared with the CA genotype, but the results did not reach statistical significance. CONCLUSIONS The TPH1 promoter SNP -347C/A differentially binds EGR-1 and correlates with IBS bowel habit subtypes and possibly colonic TPH1 expression consistent with its role in modulating intestinal 5-HT signaling.
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Affiliation(s)
- Helmut Grasberger
- Department of Internal Medicine at the University of Michigan Medical Center, Los Angeles
| | - Lin Chang
- Gail and Gerald Oppenheimer Family Center for Neurobiology of Stress, Los Angeles
| | - Wendy Shih
- Department of Biostatistics, University of California, Los Angeles
| | | | - Gregory S. Sayuk
- Division of Gastroenterology, Washington University, St. Louis,John Cochran Veteran’s Affairs Medical Center, St. Louis
| | | | - Iordanis Karagiannides
- Inflammatory Bowel Disease Center, Division of Digestive Diseases, David Geffen School of Medicine at the University of California, Los Angeles
| | - Charalabos Pothoulakis
- Inflammatory Bowel Disease Center, Division of Digestive Diseases, David Geffen School of Medicine at the University of California, Los Angeles
| | - Emeran Mayer
- Gail and Gerald Oppenheimer Family Center for Neurobiology of Stress, Los Angeles
| | - Juanita L. Merchant
- Department of Internal Medicine at the University of Michigan Medical Center, Los Angeles,Department of Molecular & Integrative Physiology at the University of Michigan Medical Center, Los Angeles
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Galligan JJ, Patel BA, Schneider SP, Wang H, Zhao H, Novotny M, Bian X, Kabeer R, Fried D, Swain GM. Visceral hypersensitivity in female but not in male serotonin transporter knockout rats. Neurogastroenterol Motil 2013; 25:e373-81. [PMID: 23594365 DOI: 10.1111/nmo.12133] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Accepted: 03/11/2013] [Indexed: 12/15/2022]
Abstract
BACKGROUND Visceral hypersensitivity occurs in irritable bowel syndrome (IBS), particularly in women. Serotonin signaling, including reduced serotonin transporter (SERT) expression, may be disrupted in IBS patients. We studied SERT gene knockout (KO) rats to determine if they exhibited sex-related alterations in visceral sensitivity. METHODS We measured serotonin in the colonic mucosa using HPLC and amperometric microelectrode techniques. Visceral sensitivity was assessed using the electromyographic visceromotor response (VMR) in response to colorectal balloon distention (CRD). We studied the electrophysiologic properties of colon projecting sensory neurons in vitro using whole-cell recordings. KEY RESULTS Mucosal serotonin levels were not different among male and female WT and SERT KO rats. Serotonin oxidation currents in vitro were larger (P < 0.05) in tissues from male and female SERT KO compared with WT rats. Oxidation currents in male and female WT, but not SERT KO, rats were increased (P < 0.05) by the SERT inhibitor fluoxetine (1 μmol L(-1) ). The VMR to CRD was increased in female but not in male SERT KO rats (P < 0.05); this response varied with the estrous cycle. Colon projecting sensory neurons from female SERT KO rats fired more action potentials compared with neurons from female WT rats. There were no differences in action potential firing in neurons from male WT and SERT KO rats. CONCLUSIONS & INFERENCES Increased colonic extracellular serotonin in female SERT KO rats is associated with visceral hypersensitivity and hyperexcitability of colon projecting sensory neurons. The SERT KO rat is a model for studying interactions between serotonin, sex and visceral sensation.
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Affiliation(s)
- J J Galligan
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA.
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Foley S, Garsed K, Singh G, Duroudier NP, Swan C, Hall IP, Zaitoun A, Bennett A, Marsden C, Holmes G, Walls A, Spiller RC. Impaired uptake of serotonin by platelets from patients with irritable bowel syndrome correlates with duodenal immune activation. Gastroenterology 2011; 140:1434-43.e1. [PMID: 21315720 DOI: 10.1053/j.gastro.2011.01.052] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 01/13/2011] [Accepted: 01/24/2011] [Indexed: 12/18/2022]
Abstract
BACKGROUND & AIMS Patients with irritable bowel syndrome with diarrhea (IBS-D) have increased mucosal serotonin (5-hydroxytryptamine [5-HT]) availability, possibly because immune activation reduces activity of the 5-HT transporter (SERT). We investigated the relationship between mucosal and platelet SERT and immune activation of the duodenal mucosa in patients with IBS-D. METHODS We quantified mucosal intraepithelial lymphocytes (IELs), mast cells, and enterochromaffin cells in blood samples, measured levels of SERT messenger RNA (mRNA) in mucosal samples, and assessed platelet uptake of 5-HT and platelet membrane binding of (3)H-paroxetine in samples from 29 healthy volunteers (HVs), 20 patients with IBS-D, and 20 untreated patients with celiac disease. RESULTS Patients with IBS-D or celiac disease had increased numbers of IELs and mast cells compared with HVs (both P < .001). Levels of SERT mRNA were reduced in the mucosa of patients with IBS-D or celiac disease and were inversely correlated with numbers of IELs (r = -0.72, P < .0001). Uptake of 5-HT by platelets from patients with IBS-D or celiac disease was reduced (mean, 17.1 ± 3.5 and 28.3 ± 4.1 nmol·min(-1)·mg(-1), respectively) compared with HVs (50.8 ± 8.0 nmol·min(-1)·mg(-1), P < .01 and P = .05, respectively). Binding of paroxetine to membranes of platelets from patients with IBS-D (median [interquartile range], 226 [92-405] fmol/mg protein) was significantly greater than that from HVs (109 [69-175] fmol/mg protein) and correlated inversely with platelet uptake of 5-HT (r = -0.62, P = .03). Tryptase release from incubated biopsy samples was significantly increased in patients with IBS-D (2.2 [0.42-3.5] vs 0.50 [0.25-0.86] ng·mL(-1)·mg(-1) for HVs; P = .03). CONCLUSIONS Platelet SERT is reduced in IBS-D and associated with reduced levels of SERT mRNA and duodenal immune activation.
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Affiliation(s)
- Stephen Foley
- National Institute for Health Research Biomedical Research Unit, Nottingham Digestive Diseases Centre, School of Clinical Sciences, Nottingham, England
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Spiller RC. Targeting the 5-HT(3) receptor in the treatment of irritable bowel syndrome. Curr Opin Pharmacol 2011; 11:68-74. [PMID: 21398180 DOI: 10.1016/j.coph.2011.02.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Revised: 02/13/2011] [Accepted: 02/14/2011] [Indexed: 12/18/2022]
Abstract
Irritable bowel syndrome, which affects 5-10% of the population includes around 25% with predominantly diarrhoea (IBS-D). Several lines of evidence suggest an increase in mucosal 5-HT availability in IBS-D including a decrease in the serotonin transporter (SERT) which is also seen following acute diverticulitis. 5-HT(3) receptor antagonists have proved effective in suppressing urgency, prolonging small and large bowel transit and relieving symptoms in IBS-D. Alosetron continues to be used under restricted availability without any serious morbidity despite ischemic colitis which occurs at a rate of <1/1000 patient year. Other agents such as ramosetron and ondansetron are still in use and have not been associated with ischemic colitis. 5-HT(3) receptor agonists stimulate intestinal motility, shorten transit times and in a pilot trial accelerated transit in patients with IBS-C.
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Affiliation(s)
- Robin C Spiller
- NIHR Biomedical Research Unit, Nottingham Digestive Diseases Centre, University Hospital, Nottingham NG7 2UH, United Kingdom.
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Lahmann C, Röhricht F, Sauer N, Noll-Hussong M, Ronel J, Henrich G, von Arnim A, Loew T. Functional relaxation as complementary therapy in irritable bowel syndrome: a randomized, controlled clinical trial. J Altern Complement Med 2010; 16:47-52. [PMID: 20064018 DOI: 10.1089/acm.2009.0084] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVES Irritable bowel syndrome (IBS) is a frequently disabling and almost invariably distressing disease with a high overall prevalence. Numerous trials identified the importance of psychogenic and emotional etiological factors, and this is obvious in clinical practice. Although relaxation techniques are frequently recommended, there is still a lack of evidence for their efficacy in the management of IBS. This study therefore aims to determine the efficacy of functional relaxation (FR) in IBS. SUBJECTS The subjects were 80 patients with IBS. INTERVENTIONS Participants were randomly allocated either to FR or to enhanced medical care (EMC: treatment as usual plus two counseling interviews) as control intervention with 2 weekly sessions over the 5-week trial each. Thirty-nine (39) patients completed FR and 39 received EMC. OUTCOME MEASURES An impairment-severity score (IS) was employed as the primary outcome parameter with assessment at baseline, after treatment, and again after 3-month follow-up. RESULTS FR was significantly superior to EMC with a standardized effect size of 0.85. The achieved effects through FR remained stable in terms of psychic and bodily impairment after 3-month follow-up. CONCLUSIONS The results of our trial suggest a positive effect of FR training on subjective functional impairment in the IS, if provided in addition to treatment as usual (TAU). There appears to be a clinically relevant long-term benefit of FR as a nonpharmacological and complementary therapy approach in IBS.
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Affiliation(s)
- Claas Lahmann
- Department of Psychosomatic Medicine and Psychotherapy, Klinikum rechts der Isar, Technische Universitaet Muenchen, Munich, Germany.
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Franke L, Schmidtmann M, Riedl A, van der Voort I, Uebelhack R, Mönnikes H, Mönnikes H. Serotonin transporter activity and serotonin concentration in platelets of patients with irritable bowel syndrome: effect of gender. J Gastroenterol 2010; 45:389-98. [PMID: 19997855 DOI: 10.1007/s00535-009-0167-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Accepted: 11/08/2009] [Indexed: 02/04/2023]
Abstract
BACKGROUND In the past decade, a strong argument has been built for the role of serotonin (5HT) and the serotonin transporter (SERT) in irritable bowel syndrome (IBS). However, it is still not clear how SERT contributes to this clinically heterogeneous disease. The present study addressed this issue by implementing platelet (plt) markers of SERT activity in the assessment protocol. METHODS Fasting blood samples of 149 (51 male/98 female) subjects with Rome II and III defined IBS subtypes, and 163 healthy control subjects (CSs; 75 male/88 female) were analyzed for platelet 5HT concentration and 5HT uptake activity [maximum uptake rate (V (max)) and affinity constant (K (m))]. RESULTS Gender had a significant impact on platelet markers of SERT activity. Male IBS patients showed significantly lower median V (max) and K (m) values than the male CS (V (max) 1.706 vs. 2.148 nmol/10(9) plts x min, P < 0.001; K (m) 346 vs. 410 nmol, P = 0.008) without any significant reduction in platelet 5HT concentration (362 vs. 394 ng/10(9) plts). On the other hand, V (max) values were not different between female IBS patients and female CS (1.642 vs. 1.741 nmol/10(9) plts x min), but platelet 5HT concentration was significantly lower in females with diarrhea-predominant IBS (363 vs. 435 ng/10(9) plts, P < 0.05). CONCLUSION Although an absolute extrapolation from platelets to the gastrointestinal tissue does not appear to be justified, our findings demonstrated that the contribution of disturbed SERT activity to IBS is not uniform and is possibly gender-specific. The results suggest that an assessment of SERT function in platelets may help to elucidate the differences between IBS patients in response to drugs affecting the 5HT system.
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Affiliation(s)
- Leonora Franke
- Department of Psychiatry and Psychotherapy, Charité-Universitätsmedizin Berlin, Campus Charité Mitte (CCM), Schumannstr. 20-21, 10117 Berlin, Germany.
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Thorslund K, El-Nour H, Nordlind K. The serotonin transporter protein is expressed in psoriasis, where it may play a role in regulating apoptosis. Arch Dermatol Res 2009; 301:449-57. [PMID: 19263059 DOI: 10.1007/s00403-009-0933-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 02/08/2009] [Accepted: 02/10/2009] [Indexed: 12/01/2022]
Abstract
Since the symptoms of psoriasis may be changed by treatment with selective serotonin reuptake inhibitors (SSRIs), the expression of serotonin (5-HT) and its transporter protein (SERT) in the skin of patients with psoriasis were examined employing a biotinylated-streptavidine procedure. In biopsies of such skin staining for 5-HT was limited to platelets; the expression of SERT in the keratinocytes of involved regions was redistributed; the numbers of SERT-positive dendritic or round mononuclear cells in the epidermis of involved psoriatic skin were higher than in normal healthy control skin; and the dermis of the involved skin contained higher numbers of round inflammatory cells immunostained for SERT than either non-involved psoriatic skin or normal skin. Double-immunostaining indicated that the skin cells expressing SERT also expressed CD1a, CD3 or tryptase. In addition, SERT immunostaining was co localized with caspase-3, a key regulator of apoptosis, but not with TUNEL staining. The present findings indicate that SERT might play a role in regulating apoptosis in inflammatory cells associated with psoriasis, in which case this protein might constitute a valuable therapeutic target.
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Affiliation(s)
- Kristofer Thorslund
- Unit of Dermatology and Venereology, Department of Medicine, Karolinska University Hospital, Solna, Stockholm 171 76, Sweden.
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Van Kerkhoven LAS, Laheij RJF, Jansen JBMJ. Meta-analysis: a functional polymorphism in the gene encoding for activity of the serotonin transporter protein is not associated with the irritable bowel syndrome. Aliment Pharmacol Ther 2007; 26:979-86. [PMID: 17877505 DOI: 10.1111/j.1365-2036.2007.03453.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Serotonin is associated with symptoms of the irritable bowel syndrome, its action is terminated by the serotonin transporter protein. AIM To assess the association between a functional polymorphism in the gene encoding for activity of the serotonin transporter protein and the irritable bowel syndrome. METHODS Meta-analysis of studies identified through a Medline, PubMed and Web of Science search, describing the prevalence of a polymorphism in the serotonin transporter gene creating long and short alleles. RESULTS Eight eligible studies described a total of 1034 patients with the irritable bowel syndrome, and 1377 healthy controls. Presence of the short allele is not associated with an increased risk for the irritable bowel syndrome: OR 1.0; 95% CI: 0.7-1.4 for homozygous subjects, and OR 1.0; 95% CI: 0.8-1.2 for homozygous subjects and heterozygotes together. Although Caucasians and Asians had diverging genotypic frequencies, no association with the shot allele and irritable bowel syndrome was observed in subgroups: Asians OR 1.2; 95% CI: 0.9-1.6 and OR 1.1; 95% CI: 0.2-5.9; Caucasians OR 0.9; 95% CI: 0.5-1.7 and OR 0.9; 95% CI: 0.7-1.2, respectively, for homozygous subjects alone and for homozygous subjects and heterozygotes together. CONCLUSION A genetic polymorphism in the gene encoding for activity of the serotonin transporter protein is not associated with the irritable bowel.
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Affiliation(s)
- L A S Van Kerkhoven
- Department of Gastroenterology and Hepatology, Radboud University, Nijmegen Medical Center, Nijmegen, The Netherlands.
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Affiliation(s)
- Robin Spiller
- Wolfson Digestive Diseases Centre, University Hospital, Nottingham NG7 2UH, UK.
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