Broncho-obstructive syndrome and the enzymes of cellular energy metabolism after coronavirus infection

Broncho-obstructive syndrome (BOS) after coronavirus infection is characterized by long-term, dry and painful cough which is hard for treatment, significantly reducing the quality of life of the patients. The goal of the study: to investigate the specific features of clinical manifestations of BOS diagnosed for the first time in patients belonging to different age groups in post-COVID-19 period and to estimate the degree of mitochondrial dysfunction by the imbalance of the enzymes of cellular energy metabolism. Materials and methods. 298 patients with BOS (age 18–78) were observed continuously for 2 years. Standard clinical, biochemical and functional examination was carried out, Saint George`s Respiratory Questionnaire (SGRQ) was used. Mitochondrial dysfunction was determined by the ratio of levels of two enzymes, lactate dehydrogenase (LDH) and succinate dehydrogenase (SDH), in peripheral blood lymphocytes. Statistical data processing was performed in STATISTICA 10.1 program package. Results. The duration and severity of BOS manifestations increased with age, they were the most prominent in the age group older than 60 y/o. Bronchial asthma was diagnosed for the first time in 85 patients, most of them belonging to the group 18–25 y/o. In all the patients with BOS, the SGRQ coeffitient was above 50, and comorbidity was established in 82.4% of the patients. The longest duration of BOS (49.4±3.5 days) was established in the group older than 60 y/o (n = 86). LDH/SDH ratio decreased from 6 to 4.8–5.2 a.u. in all the age groups. Such changes should be taken into account in the patients from young age groups. Conclusion. The revealed low values of LDH/SDH ratio have not been shown in the available literature earlier. These values demonstrate the development of secondary mitochondrial dysfunction in post-COVID-19 period in both younger and older age groups, particularly, in patients with more severe progression of BOS. Estimation of this parameter would allow to revealthe personified characteristics for each patients, which is important for quantifying the efficacy and duration of the required antioxidant therapy.