Impact of serotonin transporter gene polymorphism on gut motility in patients with type 2 Diabetes mellitus

Aastha Malik; Sarama Saha; Rajesh K Morya; Sanjay K Bhadada; Satya V Rana

doi:10.5056/jnm20211

J Neurogastroenterol Motil https://doi.org/10.5056/jnm20211

Impact of serotonin transporter gene polymorphism on gut motility in patients with type 2 Diabetes mellitus

Aastha Malik

,¹ Sarama Saha,² Rajesh K Morya,¹ Sanjay K Bhadada,³ and Satya V Rana

^1,2*

¹Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, Chandigarh, India; ²Department of Biochemistry, All India Institute of Medical Sciences Rishikesh, Uttarakhand, India; and ³Department of Endocrinology, Postgraduate Institute of Medical Education and Research, Chandigarh, India

Correspondence to: Satya V Rana, PhD
House no. 137, Sector 15 A, Chandigarh 160015, India
Tel: +91-9876139933, E-mail address: svrana25@hotmail.com

Received: September 15, 2020; Revised: November 29, 2020; Accepted: November 29, 2020; Published online: February 2, 2021.

Abstract: Background/Aims
The pathogenesis of gastrointestinal (GI) symptoms in type 2 diabetes mellitus (T2DM) patients is yet to be delineated clearly. Serotonin, a monoamine neurotransmitter, resides primarily in the gut and plays a vital role in GI system. However, no study has been documented where the role of serotonin and serotonin transporter gene (SLC6A4) polymorphism in the development of GI symptoms in T2DM patients has been described.
Methods
Three hundred diabetes patients attending diabetes clinic at Postgraduate Institute of Medical Education and Research, Chandigarh, and matched healthy controls were enrolled for this study. Plasma from collected blood sample was used for serotonin measurement by enzymelinked immunosorbent assay method and buffy coat was used for isolation of DNA by phenol chloroform method. Serotonin transporter gene polymorphism was carried out by polymerase chain reaction method.
Results
The frequency of S allele and SS genotype was significantly higher than controls and was associated with increased risk of T2DM. The frequency of LS genotype showed an association with protection from the disease. Increased numbers of T2DM patients with constipation belonged to LL (79.4%) genotype and had significantly delayed gut motility. The patients without GI symptoms did not show any association of gut motility with genotype. Furthermore, serotonin was significantly higher in diabetic patients who belonged to SS genotype compared to LS or LL genotype and who presented with diarrhea.
Conclusion
From this study it may be concluded that SS genotypes are prone to develop diarrhea because of faster gut motility resulting from higher serotonin levels as compared to LS and LL genotype in T2DM patients.; Keywords: Alleles; Diabetes mellitus, type 2; Polymorphism, genetic; Serotonin; SLC6A4 protein, human