Nitric oxide and inducible nitric oxide synthase levels in EE and NERD patients

Gastroenterol Hepatol Bed Bench. 2022 Winter;15(1):79-86.


Aim: This article aimed to evaluate nitric oxide (NO) and nitric oxide synthase (iNOS) markers in patients with erosive esophagitis (EE) and those with non-erosive reflux disease (NERD) and compare them with the control group.

Background: Gastro-esophageal reflux disease (GERD) is one of the most common disturbances of the upper digestive tract. Inducible nitric oxide synthase (iNOS) is expressed in esophageal adenocarcinoma. NO, the product of this enzyme, has been implicated in the pathogenesis of this condition. Nevertheless, the data on whether iNOS and NO are expressed in the early stages of GERD is conflicting.

Methods: In this study, tissue samples were obtained from fifty-four patients (27 with erosive esophagitis and 27 with non-erosive reflux disease) and 27 controls. Tissue concentrations of nitrite, nitrate, and iNOS were measured using Enzyme-Linked Immune-sorbent Assay (ELISA). The Bradford method was used to determine the protein concentration of samples. The results were analyzed by SPSS software (version 22.0). In multiple comparisons, the Tukey test was performed, and p < 0.05 was considered as the level of significance.

Results: Tissue amounts of iNOS were significantly higher (p= 0.001) in EE patients compared with the control group. There was a significant difference (p= 0.01) in this factor between EE patients and patients with NERD. Moreover, tissue levels of nitrite and nitrate were significantly higher (p = 0.001) in patient groups compared with the control group.

Conclusion: It was observed that NO and iNOS protein were increased in human esophagitis tissue. The results indicated that nitric oxide and iNOS levels are useful and effective markers in the pathogenesis of GERD. While the results are not certain, it is thought that a link exists between the expressions of iNOS and disease progression.

Keywords: Erosive esophagitis; Gastro-esophageal reflux disease; Nitrate; Nitrite; Non-erosive reflux disease; iNOS.