Cytokine-determined mechanisms of the pathomorphological realization of gastroesophageal reflux disease against the background of autoimmune thyroiditis in young persons

Abstract

The aim: to study the features of proinflammatory cytokine status and pathomorphological realization of gastroesophageal reflux disease (GERD) against the background of autoimmune thyroiditis (AIT) in young people.
 Materials and methods. Examinations involved 120 patients with GERD and AIT and 45 people with isolated GERD. The control group consisted of 20 volunteers matched by age, gender, and social status. All patients underwent esophagogastroduodenoscopy, histological study, comparative morphometry of the esophageal mucosa, and determination of proinflammatory cytokines’ levels: interleukin‑1β (IL‑1β), IL‑18, tumor necrosis factor‑α (TNF‑α).
 Results. The frequency of erosive GERD in the examined groups of patients did not statistically differ. At the same time, analysis of the structure of erosive GERD forms revealed a significant redistribution of esophagitis grades towards its enhancement in patients with comorbid pathology. The histological study showed that in patients with nonerosive GERD and AIT all the studied morphometric parameters had significantly deeper changes and exceeded similar indicators of the group with isolated GERD: epithelium total thickness 319.3±9.1 µm against 286.1±8.2 µm (p <0.01), epithelium basal layer thickness 79.6±3.2 µm versus 49.7±2.1 µm (p <0.01), connective tissue papillae height 224.8±7.3 µm against 172.7±4.6 µm (p <0.01), intercellular space 1.55±0.11 µm versus 1.12±0.09 µm (p <0.01). The presence of concomitant AIT was associated with a significant redistribution towards increased degrees of hyperplasia of the basal layer of the epithelium, elongation of the papillae, and leukocyte infiltration. The comorbidity of GERD and AIT in young people was associated with significant increase in the blood serum levels of proinflammatory cytokines in compared to isolated GERD: IL‑1β — 29.6 pg/ml versus 17.7 pg/ml (p <0.01), IL‑18—1763.4 pg/ml versus 614.6 pg/ml (p <0.01), TNF‑α — 7.6 pg/ml versus 5.2 pg/ml (p <0.01). Correlation analysis of the cytokine content and expressivity of certain morphometric parameters of the esophageal mucosa revealed the direct correlations.
 Conclusions. GERD and euthyroid AIT comorbidity in the student population is accompanied by significant redistribution of esophagitis grades towards its aggravation. The presence of concomitant AIT in patients with non‑erosive GERD leads to the significant intensification of the degree of epithelium basal layer hyperplasia, connective tissue papillae elongation, and polymorphic cellular inflammatory infiltration in comparison with isolated GERD, while these deviations demonstrate direct correlations with the levels of IL‑1β, IL‑18, and TNF‑α.