Medical article медицинская статья

Introduction. Liver damage can be a dangerous side effect of using isoniazid. Individual susceptibility to isoniazid in humans is dependent on the presence of N-acetyltransferase 2 allelic variants in genome. It was imperative to assess the effect of genetically determined isoniazid acetylation rate in terms of risk of developing isoniazid-induced hepatotoxicity, as well as prevention of potential hepatopathy, and improvement of tuberculosis chemotherapy safety. Aim. To study the effect of acetylation type on the incidence of isoniazid hepatotoxicity in residents of the Sakha Republic (Yakutia) with newly diagnosed pulmonary tuberculosis. Methods. The study included 112 patients with newly diagnosed pulmonary tuberculosis. Genotyping was performed using real-time polymerase chain reaction. The following single nucleotide polymorphisms were studied: rs1801280, rs1799930, rs1799931, rs1799929, rs1208, rs1041983. Hepatotoxicity was determined based on the results of clinical laboratory monitoring and using the criteria developed by the European Association for the Study of the Liver (2019). Results. Hepatotoxic reactions developed more often in slow acetylators (43.2%), compared to fast acetylators (20.7%) and intermediate acetylators (10.9%); p=0.002. Serum alanine aminotransferase activity was 5 or more times above the upper limit of normal activity in 37.8% of slow acetylators, and in 8.7% of intermediate acetylators; p=0.001. Clinical manifestations of isoniazid hepatotoxicity were observed more often in slow acetylators (29.7%), than in fast acetylators (3.4%); p=0.000. Conclusion. Slow acetylation type ought to be considered an important risk factor for developing isoniazid hepatotoxicity in patients with pulmonary tuberculosis.

Background. Tuberculosis therapy can lead to considerably dissimilar outcomes among individual patients. Some patients benefit from anti-tuberculosis chemotherapy leading to a desired therapeutic effect, while other patients show insufficient or absent response, or develop adverse side effects. Individual response to isoniazid is affected by mutations in the gene encoding N-acetyltransferase 2 (NAT2). Wide variations were observed in distributions of polymorphic NAT2 alleles in human populations depending on race, ethnicity, or geographical origin. No data are available to date on prevalence of NAT2 gene polymorphic variants and acetylation types in Yakut (Sakha) patients with newly diagnosed pulmonary tuberculosis. Aims: the frequencies of NAT2 polymorphic SNPs as well isoniazid acetylation phenotypes were evaluated in the patients cohort of Yakut ethnicity with newly diagnosed pulmonary tuberculosis (PTB). The comparison with, other ethnic groups of Asian origin was done. Methods. Cross-sectional study was conducted among Yakut patient cohorts with newly identified pulmonary tuberculosis. Using real-time PCR the following SNPs were explored: NAT2*5 (rs1801280, Т341С), NAT2*6 (rs1799930, G590A), NAT2*7 (rs1799931, G857A), NAT2*11 (rs1799929, C481T), NAT2*12 (rs1208, A803G), NAT2*13 (rs1041983, C282T). Genetically determined metabolic rates were calculated using NATpred online tool. Results. NAT2 SNPs were assessed, namely *5, *6, *7, *11, *12, and *13. The most frequent in Yakut patients were NAT2*6 and NAT2*13 SNPs (40.9% and 64.4%, respectively). Significant differences were detected in frequencies of NAT2 *5, *11, *12 polymorphisms; all studied NAT2 gene polymorphisms showed meaningful differences in genotype and minor allele prevalence rates after comparison between Yakut population and other Mongoloid ethnic groups (populations of China, Japan, Vietnam). High prevalence of intermediate acetylation type among ethnic Yakuts (58.3%) was established. Conclusions. Certain distinct differences in allelic variants of NAT2 gene and acetylation type prevalence in patients of Yakut ethnic origin newly diagnosed with pulmonary tuberculosis let conclude that the existing genotyping and phenotyping data from studies among other Mongoloid populations cannot be implicitly extrapolated on Yakut people. Pharmacogenetic data on individual response to drugs in Yakut patients should be made use of in clinical practice, to develop personalized isoniazid administration algorithms, with a final goal to make treatment more effective and safe.

Сравнительный анализ результатов генотипирования гена N-ацетилтрансферазы 2 у пациентов с впервые выявленным туберкулезом органов дыхания, проживающих в Республике Саха (Якутия)

Background: Glioblastoma is the most common and aggressive primary brain tumor in adults. The most common genetic alteration in glioblastoma is the loss of heterozygosity (LOH) of the chromosome 10q. However LOH merely reflects allelic imbalance in the area without detailed information on the gene copy number.

Background. Individual sensitivity to isoniazid in tuberculosis patients is determined by the presence of N-acetyltransferase 2 (NAT2) enzyme gene allelic variants in genome. Evaluation of quantitative and qualitative alterations in peripheral blood can be used for diagnosis, disease severity estimation, or as a clue for estimation of anti-tuberculosis chemotherapy effectiveness and safety.Aim: Find associations between acetylation type and peripheral red blood cell (RBC) dynamics; determine the effect of NAT2 acetylation rate on the effectiveness and safety of treatment in patients with newly identified pulmonary tuberculosis (TB) residing in the Sakha Republic (Yakutia).Methods. This study included 146 patients with various clinical forms of newly diagnosed pulmonary TB. Oral isoniazid, rifampicin, pyrazinamide, and ethambutol were administered patients. Genotyping was performed via real time PCR.Results. Rapid and intermediate acetylators showed an increase in hemoglobin concentrations and RBC erythrocyte hemoglobin content by the end of chemotherapy (P<0.05). Incidence of anemia was lower in intermediate acetylators, compared to rapid or slow acetylators (P=0.013). Negative correlation was established between absolute RBC count and slow acetylation type (P=0.017). Patients with rapid acetylation type showed increased RBC distribution width indexes RDW-CV and RDW-SD (P<0.05).Conclusions. An adequate therapeutic effect was achieved with standard doses of anti-TB medications in patients with intermediate acetylation type. Rapid and slow acetylators required anti-TB medication dose correction. Genotyping for NAT2 gene in patients with pulmonary TB enables clinicians to choose the optimal dose of anti-TB medications, specifically, isoniazid dose.