In this pilot exploratory study, the primary aim was to determine whether genetic polymorphisms of tryptophan hydroxylase ( TPH1/TPH2), serotonin reuptake transporter ( SERT), or catechol-O-methyltransferase ( COMT) are associated with fatigue in women with IBS.
IBS patients with depressive disorders were characterized by higher frequency of 5-HTTLPR L allele in comparison to IBS patients with anxiety disorders.
The exposure of Caco-2 cells to IBS supernatants induced a significant decrease in SERT gene expression, independently of IBS subtypes, compared with AC mucosal supernatants.
In this article, current insights regarding the regulation of SERT in IBS are provided, including aspects of SERT gene polymorphisms, microRNAs, immunity and inflammation, gut microbiota, growth factors, among others.
Different from the conclusions of the earlier meta-analyses, the 5-HTTLPR mutation affects IBS-C but not IBS-D and IBS-M development and this effect only exists in the East Asian population but not other populations.
Systemic assessment was performed for the published studies based on the association of SLC6A4 I/S polymorphism and IBS risk from PubMed (Medline), EMBASE search.
Overall, there is limited evidence of a genetic association with IBS; the most frequently studied association is with 5-HTTLPR, and the most replicated association is with TNF superfamily member 15.
A functional polymorphism in the serotonin transporter (5-HTT), which terminates serotonergic signalling, was also found associated with these psychiatric comorbidities and increased visceral sensitivity in irritable bowel syndrome, which coexistence is associated with higher dyspeptic symptom severity.
Recently, several genetic studies have suggested that serotonin transporter (SERT) gene polymorphisms and the G-protein β3 (GNβ3) C825T gene polymorphism are associated with FD and IBS.
In this case-control study, 196 Caucasian Rome II IBS patients [97 IBS-D (aged 18-66 years; 67 female) and 99 IBS-C (aged 18-65 years; 95 female)] and 92 Caucasian healthy volunteers (aged 18-63 years; 60 female) from the UK had genomic DNA extracted from peripheral blood and the 5-HTTLPR and STin2 polymorphisms genotyped.
This study was to investigate the potential association between the SERT-P polymorphism and clinical subtypes of IBS patients in the Indian population.
Genetic association studies with IBS symptom phenotype have generally provided inconsistent results for many candidate genes investigated, such as SLC6A4, GNB3, and IL-10.
There were significant associations between post-CLO responses and gene variations for DeltaGV (alpha2A and SLC6A4), rectal sensation of gas (alpha2A, GNbeta3), urgency (alpha2A); and pain (GNbeta3 and SLC6A4); and rectal compliance (SLC6A4). alpha2A, GNbeta3 and SLC6A4 genotypes significantly modify responses to CLO on sensory and motor GI functions in health and IBS.
In this exploratory study we therefore expanded the search for a possible association of the serotonin transporter with irritable bowel syndrome to include not only the 5-HTTLPR and Stin2 VNTR length polymorphisms, but also the functional single nucleotide polymorphism rs25531.
Current data on the efficacy of SSRIs in IBS, association of the SERT gene promoter polymorphism 5-HTTLPR with IBS and the expression pattern of SERT in the intestinal mucosa of IBS patients are conflicting.
There were significant associations between 5-HTTLPR SS genotype and absence of IBS symptoms and between 5-HTTLPR LS/SS genotype and increased rectal compliance and increased pain ratings, particularly at 12 and 24 mmHg distensions.
This study investigates the association of psychological symptoms with the distribution of two serotonin transporter gene (SERT) polymorphisms, located in the promoter region (5-HTTLPR) and in intron 2 (STin2 VNTR), in patients with irritable bowel syndrome (IBS).
This study investigates the association of psychological symptoms with the distribution of two serotonin transporter gene (SERT) polymorphisms, located in the promoter region (5-HTTLPR) and in intron 2 (STin2 VNTR), in patients with irritable bowel syndrome (IBS).