Gastroesophageal reflux disease (GERD) is one of the most common pathologies in the world. The prevalence of GERD in the adult population is 40%. Recent studies indicate a strong tendency to increase distribution of GERD in European countries and in Asia. Mechanisms of GERD are multifactorial and not sufficiently understood. The results of recent fundamental research allow to state that the pathogenesis of GERD include dysfunction of gastric antireflux barrier dysfunction, disorders of the autonomic nervous system, disruption of esophageal transit and clearance.

The aim of our study was to study the content of calcium, phosphorus and protein in saliva and mucosa, and ultrastructural changes in the mucosa of the distal esophagus in patients with gastroesophageal reflux disease.

14 patients with GERD (average age was 52,2±5,5 years) were examined. All patients were interviewed and an endoscopic examination of the upper gastrointestinal tract was performed. We used unstimulated saliva which was collected 30 minutes after brushing and thorough rinsing of the mouth by distilled water. The content of calcium in saliva and biopsy was measured using the calcium-sensitive dye arsenazo III, protein – the method of Lowry and the content of inorganic phosphorus in saliva – by the method of Fiske-Subbarou. Normal values of calcium, phosphorus and protein in human saliva, set on 12 healthy volunteers. The method of blind sampling in patients complaining of heartburn was taken for electron microscopic examination during endoscopy biopsy mucosa in the distal esophagus.

According to the survey of 14 patients with GERD, heartburn daily established in 13 (92,9%), belching sour – in 10 (71,4%), an unpleasant sour taste in the mouth – in 10 (71,4%). Endoscopic signs of erosive form of GERD was found in 3 (21,4%) patients, and gastroesophageal reflux endoscopically was detected in 6 (42,9%) patients. Therefore, we detected prevalence of subjective complaints (heartburn, acid regurgitation, etc.) of the objective (endoscopic signs of GERD). The authentic reduction of calcium in the saliva of patients with GERD by 36,3% and reduce phosphorus by 32,9% compared to the control group. Thus, the detected violations composition of saliva, which provides chemical clearance of the esophagus in patients with GERD. So as the next step, we determined the content of calcium and phosphorus in the biopsy of esophageal mucosa of patients with GERD. It was established that in the control and experimental groups, the calcium content in biopsy esophagus was not statistically different. So we found reduction in the concentration of calcium in the saliva, which was not accompanied by a decrease in calcium content in the cells, as it can be assumed that obviously related to the involvement of compensatory mechanisms to maintain calcium homeostasis in cells. In addition, we examined the content of inorganic phosphorus in biopsies and found increasing of its content, but that was also not statistically significant. It can be associated with an increase in cell volume of acid store, which is known to contain many inorganic phosphorus. This store includes primarily lysosomes, which are rich in digestive enzymes.

Ultramicroscopic changes of the mucous membrane of the distal esophagus were analyzed. Enlargement of intracellular contacts in the mucosa of the esophagus of the patient complaining of heartburn, which is likely to lead to deterioration of the functional state of the cell contacts was found. Thus, in the absence of endoscopic changes in the esophagus, but in the presence of heartburn installed expansion of intercellular contacts may be an early “marker” pathology of the esophagus.

In the saliva of patients with GERD a significant reduction in the concentration of calcium and 36,3% phosphorus by 32,9% compared to the control was found; content of calcium and phosphorus in the biopsy mucosa of patients with GERD and those with little healthy esophagus did not differ statistically or significantly; enlargement of intercellular contacts in patients complaining of heartburn in biopsies of esophageal mucosa by electron microscopy was verified.

Keywords: gastroesophageal reflux disease, electron microscopy, saliva

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