Features of cytokine balance in patients with precancerous gastric lesions depending on the changes in the structure of the thyroid gland

Background. The study of the cytokine balance is important due to searching the general links of the pathogenesis of comorbidity in precancerous gastric lesions and thyroid diseases. The purpose was to determine the peculiarities of the cytokine balance in terms of the level of vascular endothelial growth factor (VEGF), tumor necrotizing factor (TNF) α, interleukins (IL) 8 and IL-18 in patients with precancerous gastric lesions depending on the changes in the structure of the thyroid gland. Materials and methods. Forty-five patients with precancerous gastric lesions were examined. Inclusion criteria were as follows: intestinal metaplasia in the body and/or antrum, atrophy in the body of the stomach. According to the results of an ultrasound examination of the thyroid gland, patients are divided into the groups: group I — 19 patients with nodular changes, group II — 18 patients with diffuse changes, and group III — 8 patients without changes. The control group included 10 healthy individuals. The level of IL-8, IL-18, TNF-α, VEGF was determined in the blood serum by the enzyme immunoassay using reagent kits of the Vector-BEST company, Novosibirsk, Russia. Results. 82.2 % patients with precancerous gastric lesions developed the changes in the structure of the thyroid gland (n = 37), 42.2 % (n = 19) had nodular changes in. The concentration of IL-8 in patients of group I was higher compared with group II, III and control group by 2.0 (p < 0.05), 2.7 (p < 0.05), and 3.1 times (p < 0.05), respectively. The concentration of TNF-α in group I was significantly higher compared with the II, III and control groups by 2.3 (p < 0.05), 3.5 (p < 0.05), and 1.4 times (p < 0.05), respectively. A correlation between the level of TNF-α and IL-8 (r = 0.487, p = 0.001) was established. The level of VEGF was significantly increased in group I by 4.3 times (p < 0.05) and in group II by 2.5 times (p < 0.05) compared with the control. Also, in patients of group I, its content was significantly higher — 1.7 and 2.9 times compared with groups II and III (p < 0.01 and p < 0.001, taking into account the Bonferroni correction, respectively). According to the results of the Kruskal-Wallis test, the difference in VEGF level between groups was 0.002. VEGF expression correlates with the level of TNF-α (r = 0.442, p = 0.004) and with the level of IL-8 (r = 0.319, p = 0.042). A direct association was found between the level of VEGF and the simultaneous detection of intestinal metaplasia in the body and antrum (r = 0.443, p = 0.008), intestinal metaplasia in the body, antrum and angle of the stomach (r = 0.404, p = 0.024), intestinal metaplasia in the stomach body (r = 0.340, p = 0.039). Conclusions. 82.2 % patients with precancerous gastric lesions were found to have the changes in the structure of the thyroid gland, which is accompanied by an increase in the VEFG level, which directly correlates with the intestinal metaplasia in the stomach. 42.2 % of patients showed nodular changes in the thyroid gland, which is also accompanied by an increase in the levels of IL-8 and TNF-α. Such data indicate the importance of further studying of the role of cytokines in the development of comorbidity in precancerous gastric lesions.