CONTRIBUTION OF TRYPTOPHAN AND TRIMETHYLAMINE N-OXIDE DYSREGULATION TO THE MOLECULAR MECHANISMS OF LONG COVID-19 DEVELOPMENT DEPENDING ON THE CT STAGE OF LUNG INVOLVEMENT

Relevance . COVID-19, caused by the SARS-CoV-2 virus, is characterized by a wide range of clinical manifestations, from asymptomatic to critical forms with multiple organ failure. One of the key prognostic factors of the severity of the disease is the degree of damage to the lung tissue according to CT data, reflecting the severity of the inflammatory and immune response. Patients retain symptoms after the acute period, including fatigue, cognitive impairment, and myalgia, the pathogenesis of which is not fully understood. Current data indicate a significant role of metabolic disorders in the development of Long COVID-19. It has been shown that in patients with severe COVID-19 and higher CT scores, there is a decrease in tryptophan levels, activation of its catabolism via the kynurenine pathway, as well as an increase in trimethylamine N-oxide (TMAO) levels, which have proinflammatory activity. Despite numerous studies, there is insufficient data on the role of tryptophan and trimethylamine N-oxide molecules in the pathogenesis of Long COVID-19 and their relationship to severity during acute COVID-19. Aim. To study the relationship between the degree of lung damage in acute COVID-19 and tryptophan and TMAO levels in patients with Long COVID-19. Materials and methods. The retrospective cohort study was conducted, which included 30 people. The concentration of tryptophan and TMAO in the patients' plasma was determined using the method of highly efficient liquid chromatography with mass-selective mass spectrometric detection (HPLC-MS/MS). Results and discussion. As a result, the median tryptophan level in the moderate group was 9.62 [8.11; 10.50] mcmol/l, in the severe group was 4.68 [2.81; 5.05] mcmol/l, respectively. The median TMAO level in the moderate group was 0.57 [0.51; 0.81] mcmol/l, in the severe group 1.88 [1.07; 3.08] mcmol/l. Conclusions. Statistically significant differences were found between tryptophan levels and the moderate and severe groups. The significance level when comparing tryptophan concentrations was p=0.000. Statistically significant differences were also found between the level of TMAO and the severity of patients, the significance level was p<0.001.