Development Of Antituberculosis Drug-induced Hepatotoxicity Research Articles

NAT2 polymorphism and clinical factors that increase antituberculosis drug-induced hepatotoxicity.

Aim: Hepatotoxicity is a known adverse effect of antituberculosis drugs. The NAT2 gene polymorphism has been associated with an increased risk of antituberculosis drug-induced hepatotoxicity (ATDIH). Materials & methods: This study investigates the association of NAT2 polymorphism and clinical risk factors that may contribute to the development of ATDIH. The authors sequenced the NAT2 region of 33 tuberculosis patients who developed ATDIH and 100 tuberculosis patients who did not develop ATDIH during tuberculosis treatment. NAT2 haplotypes were inferred and NAT2 acetylator status was predicted from the combination of the inferred haplotypes. Multiple logistic regression was performed to identify possible factors that are associated with ATDIH. Results: The TT genotype of NAT2*13A and the AA genotype of NAT2*6B were found to be substantially linked with the risk of ATDIH, with odds ratios of 3.09 (95% CI: 1.37-6.95) and 3.07 (95% CI: 1.23-7.69), respectively. NAT2 slow acetylators are 3.39-times more likely to develop ATDIH. Factors that were associated with ATDIH include underlying diabetes mellitus (adjusted odds ratio[AOR]: 2.96; 95% CI: 1.05-8.37), pre-treatment serum bilirubin (AOR: 1.09; 95% CI: 1.02-1.16) and NAT2 slow acetylator (AOR: 3.77; 95% CI: 1.51-9.44). Conclusion: Underlying diabetes mellitus, having a higher baseline bilirubin and being a slow acetylator are identified as the risk factors associated with ATDIH among patients in Malaysia.

Association of ABCC Gene Polymorphism With Susceptibility to Antituberculosis Drug-Induced Hepatotoxicity in Western Han Patients With Tuberculosis.

Six-month combination regimens could lead to serious hepatotoxicity, which may limit the clinical use of antituberculosis drugs. ABCC transporters are critical to the influx and efflux of compounds into and out of cells. The aim of this study was to explore whether the genetic variants in ABCC genes were related to the development of antituberculosis drug-induced hepatotoxicity. Here, we screened and genotyped 39 single-nucleotide polymorphisms of 13 ABCC genes in 746 eligible patients treated by first-line antituberculosis drugs in Western China Hospital. Genomic DNA was extracted from a peripheral blood sample of each patient, and clinical symptoms and laboratory results were recorded regularly. We found that the incidence rate of hepatotoxicity was 15.8% in the western Chinese Han population. As a result, the ABCC2 rs3740065 genotype, sex, and the baseline level of alanine aminotransferase are independent risk factors of antituberculosis drug-induced hepatotoxicity, with P values of .008, .014, and <.001, respectively. Our findings revealed a fraction of the underlying mechanism of hepatotoxicity, and larger validation studies on different populations are warranted to confirm these findings.

Rs1800796 of the IL6 gene is associated with increased risk for anti-tuberculosis drug-induced hepatotoxicity in Chinese Han children

Previous studies have revealed the important contribution of the immune response and oxidative stress to the development of anti-tuberculosis drug-induced hepatotoxicity (ATDH). To investigate whether single-nucleotide polymorphisms (SNPs) of the cytokine gene interleukin-6 (IL6) and oxidative stress genes xanthine dehydrogenase/oxidase (XO) and inducible nitric oxide synthase (NOS2) were associated with susceptibility to ATDH, we performed a case-control study including 41 ATDH cases and 116 ATDH-free controls in Chinese Han children. Significant difference in the allele distribution of rs1800796 in the IL6 gene was observed between the case and control groups, and the G allele of rs1800796 was associated with an increased risk for ATDH (odds ratio: 2.48, 95%CI: 1.40–4.40, P = 0.002). However, no significant difference was observed in the allele and genotype distributions of the other SNPs of the IL6, XO and NOS2 genes between the case and control groups after Bonferroni correction. In addition, no interaction was found between all selected SNPs. These findings indicate that genetic variants of the IL6 gene might contribute to the development of ATDH in the Chinese Han pediatric population.

Analysis of silent information regulator 1 (SIRT1) gene polymorphisms in antituberculosis- drug-induced hepatotoxicity in a prospective cohort study.

Antituberculosisdrug-induced hepatotoxicity (ATDH) is a common and sometimes serious side effect related to tuberculosis (TB) treatment. A number of risk factors and host genetics contribute to the development of ATDH. However, genetic factors of ATDH remain to be identified. Silent Information Regulator 1 (SIRT1), an essential metabolism gene, was proved to be involved in ATDH in mice. The aim of this investigation was to study the association between ATDH and tag-single nucleotide polymorphisms (tag-SNPs) of the SIRT1 gene in a prospective cohort study in patients with TB. 280 newly diagnosed TB patients were recruited in this study before starting first line anti-TB treatment and were followed up for 3 months after initiating anti-TB therapy. The tag-SNPs were selected by using Haploview 4.2 based on the HapMap database of Han Chinese Beijing. Genotyping was performed by polymerase chain reaction (PCR) and the Sequenom MassARRAY iPLEX platform. 24 (9.8%) of the 245 patients included in the final analysis developed hepatotoxicity during the following up period. No significant differences in the allele, genotype, or haplotype frequency distributions of the tag- SNPs (rs7069102, rs2273773, rs4746720) of the SIRT1 gene were identified between the ATDH and non-ATDH groups (all p > 0.05). The SIRT1 gene may not contribute to the risk for developing hepatotoxicity during anti-TB treatment in the Han Chinese population.

TagSNP rs1495741 as a useful molecular marker to predict antituberculosis drug-induced hepatotoxicity.

It has been widely reported that the slow acetylator phenotype of N-acetyltransferase 2 (NAT2) is associated with the development of antituberculosis drug-induced hepatotoxicity (ATDH). The aim of this report was to evaluate the level of agreement and accuracy of two recently recommended markers, the two-single nucleotide polymorphisms (SNP) (C282T and T341C) and tagSNP of NAT2 (rs1495741) genotypes, to predict the seven-SNP-inferred NAT2 phenotype in Bolivian and Argentinian tuberculosis (TB)-patient populations. In addition, we analyzed the association of these markers with ATDH. We examined 331 TB patients who had been treated with anti-TB drugs. TagSNP of NAT2 genotyping was determined using PCR-restriction fragment length polymorphisms. The seven SNPs of NAT2 were determined using sequencing. Concordance analysis was carried out using Kendall's tau-b coefficient (w) and the degree of agreement with Cohen's κ coefficient (κ). Receiver operating characteristic receiver operating characteristic curves were obtained to measure the specificity and sensitivity of the method. A binary logistic regression was performed to identify variables associated with the development of ATDH. Both predictors showed a remarkable concordance (>95.0%) and an almost perfect agreement (κ>0.945; P<0.0001) with the predicted acetylator profile. However, the sensitivity of the tagSNP genotypes to predict the NAT2 acetylator phenotype was lower in the Bolivian population (92.3%) compared with the Argentinian population (100.0%). A nearly perfect agreement between both predictors and the predicted acetylation profile was observed with very high levels of sensitivity (>97%) and specificity (>98.0%). Furthermore, and as expected, both the two-SNP (C282T, T341C) and tagSNP were found to be independent variables in predicting ATDH with the same strength as seven-SNP of NAT2.

CYP7A1, BAAT and UGT1A1 polymorphisms and susceptibility to anti-tuberculosis drug-induced hepatotoxicity.

Evidence indicates that the polymorphisms in genes involved in bile acid metabolism may play an important role in the development of anti-tuberculosis drug-induced hepatotoxicity (ATDH) in tuberculosis (TB) patients treated with anti-tuberculosis drugs. To investigate the association between genetic variants of CYP7A1, BAAT and UGT1A1 and the risk of ATDH in a Chinese cohort. In this nested case-control study, 89 TB patients with ATDH and 356 matched ATDH-free TB patients constituted cases and controls, respectively. Genetic polymorphisms of CYP7A1, BAAT and UGT1A1 were determined using the TaqMan single-nucleotide polymorphism genotyping assay. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using a conditional logistic regression model. Significant differences were found in genotype distributions of rs1457043 in CYP7A1 between patients with and those without ATDH (P = 0.014). Genotype and haplotype analysis showed that patients carrying an AG genotype of rs1457043 and G-C or G-A haplotypes of rs1457043-rs8192870 in CYP7A1 were at a higher risk of ATDH than those with GG genotype and A-C haplotype, with ORs of respectively 2.05 (95%CI 1.18-3.15) and 2.40 (95%CI 1.62-3.57). Genetic polymorphisms of CYP7A1 may be associated with susceptibility to ATDH in the Chinese population.

Key factors of susceptibility to anti-tuberculosis drug-induced hepatotoxicity.

Anti-tuberculosis drug-induced hepatotoxicity (ATDH) is one of the leading adverse drug reactions during the course of tuberculosis treatment and poses a considerable challenge to clinicians and researchers. Previous studies have revealed the important contribution of drug metabolism and transporter enzymes to the complexity of ATDH. The emerging roles of immune response and oxidative stress resulting from reactive metabolite in the development of ATDH have also gained attention recently. Both non-genetic and genetic factors can have a significant impact on the susceptibility to ATDH, consequently altering the risk of hepatotoxicity in susceptible individuals. Non-genetic risk factors associated with ATDH include host factors, environment factors and drug-related factors. Genetic factors contributing to the susceptibility of ATDH involve genetic variations in bioactivation/toxification pathways via the cytochrome P450 enzymes (phase I), detoxification reactions by N-acetyl transferase 2, glutathione S-transferase and uridine diphosphate glucuronosyltransferase (phase II) and hepatic transport (phase III), together with immunological factors and antioxidant response. Better understanding of these factors may help to predict and prevent the occurrence of ATDH and develop more effective treatments. This review focuses on the mechanisms of ATDH and the key factors of susceptibility associated with drug metabolism, hepatic transport, immune response and oxidative stress.

Association of polymorphisms in drug transporter genes (SLCO1B1 and SLC10A1) and anti-tuberculosis drug-induced hepatotoxicity in a Chinese cohort

This study investigated the association between genetic variants in two hepatic uptake transporter genes (SLCO1B1 and SLC10A1) and the risk of anti-tuberculosis drug-induced hepatotoxicity (ATDH) in a Chinese cohort. The frequencies and distributions of single nucleotide polymorphisms (SNPs) and haplotypes of these genes were compared among 89 incident ATDH cases and 356 matched ATDH-free controls using a multivariate conditional logistic regression analysis. After correction for potential confounding factors, significant differences were found in polymorphism of rs4149014 under an addictive model (P = 0.008) and a recessive model (P = 0.016). The result of haplotype analysis suggested that patients carrying at least one SLCO1B1*15 haplotype had a higher risk of ATDH (odds ratio (OR) = 1.74, 95% confidence intervals (CI): 1.04-2.90, P = 0.034) in comparison with those carrying SLCO1B1*1a or SLCO1B1*1b haplotypes. These findings indicate that genetic variants of SLCO1B1 are associated with the development of ATDH in Chinese population.

Association of NAT2, GST and CYP2E1 polymorphisms and anti-tuberculosis drug-induced hepatotoxicity

Adherence to the prescribed anti-tuberculosis drug (ATD) treatment is crucial for curing patients with active TB. Anti-tuberculosis drug (ATD) induced hepatotoxicity (ATDH) may contribute to ATD's poor compliance in patients with tuberculosis (TB) as interruption of treatment and the switch to second-line anti-tuberculosis drugs, which is required in patients who do not tolerate standard drugs, may result in a sub-optimal treatment response. Isoniazid (INH) is a part of ATD and involved with ATDH due to toxic metabolites produced on its metabolism in liver, attributed to the variation in enzymes involved in this pathway like N-acetyltransferase 2 (NAT2), cytochrome P4502E1 (CYP2E1) and glutathione S-transferases (GSTs). The present study aimed at analysis of polymorphism at three loci of NAT2, two loci of GST and one locus on CYP2E1 and development of ATDH in patients undergoing ATD therapy. A total of 408 newly diagnosed patients with tuberculosis were enrolled for this study and at the end of sampling, 17 ATDH cases and 391 non-ATDH cases were reported. The genetic polymorphisms of the NAT2 and CYP2E1 genes were studied by PCR-RFLP and GSTM1 and GSTT1 were evaluated by multiplex PCR. Slow phenotype of NAT2 was found to be a risk factor for developing ATDH when compared to fast acetylators. Slow haplotype C481A590G857 and an intermediate acetylator haplotype T481A590G857 were found to be significantly associated with development of ATDH. GSTM1 and GSTT1 double null genotype was also reported to be associated with ATDH development. The heterozygote genotype 'c1c2' of CYP2E1 was also seen to contribute towards elevated risk of ATDH. 'c2' allele absence in females ATDH group can be considered as a protective factor against development of ATDH. In males, presence of 'c1c2' allele was seen to contribute towards elevated risk of ATDH development.

Isoniazid and its toxic metabolite hydrazine induce in vitro pyrazinamide toxicity

Antituberculosis drug-induced hepatotoxicity (ATDH) complicates the treatment of 5–10% of patients treated for active tuberculosis (TB). Knowledge regarding the mechanism of toxicity is still incomplete. Metabolism and the formation of toxic metabolites of the TB drugs may play an important role in the development of ATDH. We studied hepatotoxicity and interactions between isoniazid (INH), its toxic metabolite hydrazine (HYD), rifampicin (RIF) and pyrazinamide (PZA) in human hepatoma cells (HepG2). After 24 h pre-treatment with a non-toxic concentration of one of the four compounds, cells were exposed to increasing concentrations of INH, HYD, RIF or PZA. To determine whether pre-treatment increased toxicity, changes in the concentration at which 50% of cell growth was inhibited (IC 50) were quantified using the WST-1 cytotoxicity assay. Pre-treatment with INH, HYD or RIF decreased the INH IC 50 by 24%, 26% and 15%, respectively, meaning that INH toxicity was increased. INH and HYD pre-treatment decreased the PZA IC 50 by 30% and 38%, respectively. HYD and RIF toxicity were not affected by the pre-treatments. The present study is the first to demonstrate that pre-treatment with INH or its toxic metabolite HYD increases the in vitro toxicity of PZA. In addition, pre-treatment with INH, HYD or RIF increases the in vitro toxicity of INH. These results give us greater insight into the development of ATDH.

Phagocytes produce immunogenic drug metabolites of procainamide (PA) and gold(I) sodium thlomalate (GST): Demonstration by sensitized T cells

Adherence to the prescribed anti-tuberculosis drug (ATD) treatment is crucial for curing patients with active TB. Anti-tuberculosis drug (ATD) induced hepatotoxicity (ATDH) may contribute to ATD's poor compliance in patients with tuberculosis (TB) as interruption of treatment and the switch to second-line anti-tuberculosis drugs, which is required in patients who do not tolerate standard drugs, may result in a sub-optimal treatment response. Isoniazid (INH) is a part of ATD and involved with ATDH due to toxic metabolites produced on its metabolism in liver, attributed to the variation in enzymes involved in this pathway like N-acetyltransferase 2 (NAT2), cytochrome P4502E1 (CYP2E1) and glutathione S-transferases (GSTs). The present study aimed at analysis of polymorphism at three loci of NAT2, two loci of GST and one locus on CYP2E1 and development of ATDH in patients undergoing ATD therapy.A total of 408 newly diagnosed patients with tuberculosis were enrolled for this study and at the end of sampling, 17 ATDH cases and 391 non-ATDH cases were reported. The genetic polymorphisms of the NAT2 and CYP2E1 genes were studied by PCR-RFLP and GSTM1 and GSTT1 were evaluated by multiplex PCR.Slow phenotype of NAT2 was found to be a risk factor for developing ATDH when compared to fast acetylators. Slow haplotype C481A590G857 and an intermediate acetylator haplotype T481A590G857 were found to be significantly associated with development of ATDH. GSTM1 and GSTT1 double null genotype was also reported to be associated with ATDH development. The heterozygote genotype ‘c1c2’ of CYP2E1 was also seen to contribute towards elevated risk of ATDH. ‘c2’ allele absence in females ATDH group can be considered as a protective factor against development of ATDH. In males, presence of ‘c1c2’ allele was seen to contribute towards elevated risk of ATDH development.