Serotonin Transporter Gene (SLC6A4) Polymorphism and Mucosal Serotonin Levels in Southeastern Iranian Patients with Irritable Bowel Syndrome.
BACKGROUND Irritable bowel syndrome (IBS) is a digestive system disorder with an unknown etiology. Serotonin has a key role in the secretion and motility of the intestine. Polymorphism in serotonin re-uptake transporter (SERT or SLC6A4) gene may have a functional role in the gut of patients with IBS. The aims of the present study were to investigate the association between SLC6A4 gene polymorphism and IBS and to detect the correlation between rectal serotonin levels and IBS sub-types. METHODS SLC6A4 gene polymorphism in 131 patients with IBS and 211 healthy controls were analysed using the quantitative polymerase chain reaction high-resolution melting (qPCR-HRM) curve technique. Serotonin was measured in rectal biopsies of patients with IBS using the enzyme-linked immunosorbent assay (ELISA) method. RESULTS The patients were categorized into three groups: IBS with diarrhoea (IBS-D): 70 patients, IBS with constipation (IBS-C): 18 patients, and IBS with mixed symptoms (IBS-M): 43 patients. The frequency of SLC6A4 s/s and l/s genotypes was significantly higher in IBS-C than IBS-D, IBS-M, and controls (p=0.036). Serotonin levels were similar in IBS sub-types. CONCLUSION SLC6A4 polymorphism is a possible candidate gene associated with the pathogenesis of IBS-C. Although serotonin levels did not differ in rectal biopsies of IBS sub-types, further investigation is recommended.
Immunology Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran ; Department of Immunology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
Mojgan
M
Mohammadi
Department of Gastroenterology, Afzalipour Hospital, Kerman University of Medical Sciences, Kerman, Iran.
Hossein
H
Tahmasebi Abdar
Department of Microbiology and Virology, Kerman University of Medical Sciences, Kerman, Iran.
Hamid Reza
HR
Mollaei
Physiology Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran.
Hossein
H
Hajghani
Modeling in Health Research Centre, Institute of Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran.
Mohammad Reza
MR
Baneshi
Gastroenterology and Hepatology Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences, Kerman, Iran.
Mohammad Mahdi
MM
Hayatbakhsh
IBS; SERT; SLC6A4; Serotonin