Serotonin and Melatonin in Human Lower Gastrointestinal Tract

Rosa Vaccaro; Arianna Casini; Carola Severi; Antonietta Lamazza; Annamaria Pronio; Rossella Palma

doi:10.3390/diagnostics13020204

Serotonin and Melatonin in Human Lower Gastrointestinal Tract

Diagnostics (Basel). 2023 Jan 5;13(2):204. doi: 10.3390/diagnostics13020204.

Authors

Rosa Vaccaro¹, Arianna Casini¹, Carola Severi², Antonietta Lamazza³, Annamaria Pronio⁴, Rossella Palma⁴

Affiliations

¹ Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, Sapienza University of Rome, 00161 Rome, Italy.
² Department of Translational and Precision Medicine, Sapienza University of Rome, 00161 Rome, Italy.
³ Department of General, Plastic and Urologic Surgery, Sapienza University of Rome, 00161 Rome, Italy.
⁴ Department of General Surgery and Surgical Specialties, Sapienza University of Rome, 00161 Rome, Italy.

Abstract

Background and aims: Melatonin is a ubiquitous hormone produced not only by the pineal gland but also by other organs and tissues. It is involved in the regulation of several gastrointestinal functions. The main cells responsible for the production and release of extrapineal melatonin are the enterochromaffin (EC) cells that produce serotonin. They are involved in the pathogenesis of neuromotor disorders that characterize functional gastrointestinal disorders and in the pathophysiology of inflammatory intestinal diseases. Our aim was the immunohistochemical highlighting on biopsy samples of normal gastrointestinal mucosa and in ulcerative colitis (UC) of immunoreactive cells for melatonin and serotonin in order to identify any differences in their distribution.

Materials and methods: Our prospective case-control study involves the highlighting on human mucosal biopsies of immunoreactive cells for melatonin and serotonin. All patients undergoing colonoscopy + ileoscopy were considered eligible for the study, divided into two groups: 1. patients with active ulcerative colitis (UC); 2. control group consisting of patients undergoing endoscopic examination for colorectal cancer screening.

Results: Twenty-one patients were enrolled. The controls had a higher concentration of EC cells containing 5HT particularly in the rectum (p value ≤ 0.05). In patients with active colitis the expression of 5-HT-iR was greater in all tracts of the colon. The correlation analysis in UC patients shows that a higher expression of 5-HT-iR+ cells corresponds to a lower extension of the disease and a greater severity of the same.

Conclusions: 5HT+ cells decreased in the case of UC compared to healthy controls. In the severe disease, there was an increase in the expression of melatonin-secreting cells, probably as a compensatory response to the inflammation and oxidative stress. This increase is negatively correlated with the extent of the disease and positively with the severity of the same.

Keywords: enterochromaffin cells; inflammatory disease; lower gastrointestinal tract; melatonin; serotonin; ulcerative colitis.

Grants and funding

This research received no external funding.