Effect of furazolidone on sister-chromatid exchanges, cell proliferation kinetics, and mitotic index in vivo and in vitro

Outcomes of furazolidone- and amoxicillin-based quadruple therapy for Helicobacter pylori infection and predictors of failed eradication

AIM

To evaluate the outcomes of furazolidone- and amoxicillin-based quadruple therapy for treatment of Helicobacter pylori (H. pylori) infection and identify predictors of failed eradication.

METHODS

Patients with H. pylori infection treated with furazolidone, amoxicillin, bismuth, and proton pump inhibitor therapy (January 2015 to December 2015) who received the ¹³C-urea breath test > 4 wk after treatment were evaluated. Demographic and clinical data including prior H. pylori treatment attempts, medication adherence, alcohol and cigarette consumption during therapy, and treatment-related adverse events were recorded by reviewing medical records and telephone surveys. H. pylori eradication rates for overall and subgroups were evaluated. Multivariate analysis was performed to identify independent predictors of failed H. pylori eradication.

RESULTS

Of the 992 patients treated and retested for H. pylori infection, the overall eradication rate was 94.5% [95% confidence interval (CI): 94.1%-95.9%]. H. pylori eradication rate of primary therapy was 95.0% (95%CI: 93.5%-96.5%), while that of rescue therapy was 91.3% (95%CI: 86.8%-95.8%). Among the 859 patients who completed the study protocol, 144 (17%) reported treatment-related adverse events including 24 (3%) leading to premature discontinuation. On multivariate analysis, poor medication adherence [adjusted odds ratio (AOR) = 6.7, 95%CI: 2.8-15.8], two or more previous H. pylori treatments (AOR = 7.4, 95%CI: 2.2-24.9), alcohol consumption during therapy (AOR = 4.4, 95%CI: 1.5-12.3), and possibly smoking during therapy (AOR = 1.9, 95%CI: 0.9-4.3) were associated with failed H. pylori eradication.

CONCLUSION

Furazolidone- and amoxicillin-based quadruple therapy for H. pylori infection in an area with a high prevalence of clarithromycin resistance demonstrated high eradication rates as primary and rescue therapies with a favorable safety profile. Patient education targeting abstinence from alcohol during therapy and strict medication adherence may further optimize H. pylori eradication.

Involvement of the activation of Nrf2/HO-1, p38 MAPK signaling pathways and endoplasmic reticulum stress in furazolidone induced cytotoxicity and S phase arrest in human hepatocyte L02 cells: modulation of curcumin

Furazolidone (FZD) is extensively used as the antiprotozoal and antibacterial drug in clinic. The previous study has shown that curcumin pretreatment could improve FZD induced cytotoxicity by inhibiting oxidative stress and mitochondrial apoptotic pathway. The current study aimed to investigate the potential roles of endoplasmic reticulum (ER) stress, p38 mitogen-activated protein kinases (p38 MAPK) signaling pathway in curcumin against FZD cytotoxicity by using human hepatocyte L02 cells. The results showed that curcumin could markedly attenuate FZD induced cytotoxicity. Compared with FZD alone group, curcumin pretreatment significantly reduced the expression of phospho (p)-p38, cyclin D1, p-checkpoint kinase 1 (ChK1) and breast cancer associated gene 1 (BRCA1) protein, followed to attenuate S phase arrest. Meanwhile, curcumin pretreatment prevented FZD induced ER stress, evidenced by the inhibition of glucose-regulated protein 78 and DNA damage inducible gene 153/C/EBP-homologous protein (GADD153/CHOP) protein expression. Moreover, compared with the control, FZD exposure activated the protein and mRNA expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1), which were further activated by curcumin treatment. These results reveal that curcumin could prevent FZD induced cytotoxicity and S phase arrest, which may involve the activation of Nrf2/HO-1 pathway and the inhibition of p38 MAPK pathway and ER stress.

Curcumin Ameliorates Furazolidone-Induced DNA Damage and Apoptosis in Human Hepatocyte L02 Cells by Inhibiting ROS Production and Mitochondrial Pathway

Furazolidone (FZD), a synthetic nitrofuran derivative, has been widely used as an antibacterial and antiprotozoal agent. Recently, the potential toxicity of FZD has raised concerns, but its mechanism is still unclear. This study aimed to investigate the protective effect of curcumin on FZD-induced cytotoxicity and the underlying mechanism in human hepatocyte L02 cells. The results showed that curcumin pre-treatment significantly ameliorated FZD-induced oxidative stress, characterized by decreased reactive oxygen species (ROS) and malondialdehyde formation, and increased superoxide dismutase, catalase activities and glutathione contents. In addition, curcumin pre-treatment significantly ameliorated the loss of mitochondrial membrane potential, the activations of caspase-9 and -3, and apoptosis caused by FZD. Alkaline comet assay showed that curcumin markedly reduced FZD-induced DNA damage in a dose-dependent manner. Curcumin pre-treatment consistently and markedly down-regulated the mRNA expression levels of p53, Bax, caspase-9 and -3 and up-regulated the mRNA expression level of Bcl-2. Taken together, these results reveal that curcumin protects against FZD-induced DNA damage and apoptosis by inhibiting oxidative stress and mitochondrial pathway. Our study indicated that curcumin may be a promising combiner with FZD to reduce FZD-related toxicity in clinical applications.

Review: clinical management of Helicobacter pylori infection in China

Helicobacter pylori (H. pylori) infection has been associated with gastric disorders. The situation of H. pylori infection in China-where a high prevalence of H. pylori infection, a high incidence of gastric cancer, and widespread resistance to clarithromycin, metronidazole, and levofloxacin exist-is quite different from that in Western countries. In order for Chinese clinicians to better manage H. pylori infection, a Chinese Study Group on H. pylori published four consensus reports regarding the management of H. pylori infection in China between 1999 and 2012. The eradication rate with standard triple therapy was <80% in most areas of China. Bismuth is available in China, and bismuth-containing quadruple therapy has been shown to produce a high eradication rate; thus, bismuth quadruple therapy could be recommended both as an initial and as a rescue therapy in China. There is no advantage of sequential therapy over triple therapy in Chinese patients, but the efficacy of concomitant therapy must be studied further. This review introduces the epidemiology, diagnosis, indicators, and therapies for the eradication of H. pylori in China in recent years.

Furazolidone-based therapies for Helicobacter pylori infection: a pooled-data analysis

BACKGROUND/AIM

Furazolidone-based therapies are used in developing countries to cure Helicobacter pylori infection due to its low cost. The low bacterial resistance toward furazolidone may render appealing the use of this drug even in developed countries. However, some relevant safety concerns do exist in using furazolidone.

PATIENTS AND METHODS

This was a systematic review with pooled-data analysis of data regarding both eradication rate and safety of furazolidone-based therapies for H. pylori infection. Intention-to-treat (ITT) and per-protocol (PP) eradication rates were calculated.

RESULTS

Following furazolidone-based first-line therapy, H. pylori eradication rates were 75.7% and 79.6% at ITT and PP analysis, respectively (P<0.001). The overall incidence of side effects and severe side effects were 33.2% and 3.8%, respectively. At multivariate analysis, only high-dose furazolidone was associated with increased therapeutic success (OR: 1.5, 95% CI: 1.3-2.7; P<0.001), while occurrence of side effects was relevant following treatment for a long duration (OR: 2.9, 95% CI: 2.2-4.1; P<0.001), high-dose furazolidone (OR: 2.3, 95% CI: 1.7-3.2; P<0.001) and bismuth-containing regimens (OR: 2.1, 95% CI: 1.5-2.8; P<0.001).

CONCLUSIONS

Furazolidone-based regimens usually achieve low eradication rates. Only a high-dose regimen improves the cure rate, but simultaneously increases the incidence of severe side effects. Therefore, we suggest that patients have to be clearly informed about the possible genotoxic and carcinogenetic effects for which furazolidone use is not approved in developed countries.

Furazolidone induced oxidative DNA damage via up-regulating ROS that caused cell cycle arrest in human hepatoma G2 cells

Furazolidone (FZD) is an antimicrobial agent that has been shown to have mutagenic, genotoxic and potentially carcinogenic properties when tested in a variety of systems in vitro and in vivo. In this study, we investigated FZD's DNA damaging effect in human hepatoma cells aiming at further defining the molecular mechanism of FZD's cytotoxicity. Addition of FZD resulted in cell growth suppression and cell cycle arrest in S phase accompanied by remarkable DNA strand breaks with increased levels of intracellular reactive oxygen species (ROS) and 8-hydroxydeoxyguanosine. Activities of antioxidases were down-regulated following FZD treatment and antioxidant agent catalase and superoxide dismutase ameliorated FZD's DNA damaging effects. Moreover, FZD caused much more extensive damage to mitochondrial DNA (mtDNA) than to nuclear DNA for which the decrease in mtDNA content correlated with FZD usage in a dose-dependent manner. However, there was no evidence of FZD induced mtDNA mutation in the mitochondrial DNA displacement loop. These results demonstrate that FZD up-regulates the production of intracellular ROS to cause oxidative DNA damage with mtDNA being the most vulnerable targets. Oxidative stress and the injury of mtDNA could be early indicators of FZD-induced cytotoxicity, with the resulting abnormal progression of the cell cycle.

Comparative genotoxic evaluation of 2-furylethylenes and 5-nitrofurans by using the comet assay in TK6 cells

The genotoxicity of three 2-furylethylene derivatives and four 5-nitrofurans was evaluated by using the comet assay in human lymphoblastoid cultured TK6 cells. The 2-furylethylene derivatives were 2-furyl-1-nitroethene, 1-(5-bromofur-2-yl)-2-nitroethene and 1-(5-bromofur-2-yl)-2-bromo-2-nitroethene, while the 5-nitrofurans were nitrofurantoin, nitrofurazone, furazolidone and 5-nitro-2-furanacrolein. The treatments lasted for 3 h in the absence of metabolic activation. No genotoxic effects were observed for two of the 2-furylethylene compounds, while the derivative 1-(5-bromofur-2-yl)-2-nitroethene showed a statistically significant response mainly at the highest concentration tested; this effect was considered biologically relevant and the compound was classified as slightly genotoxic. On the other hand, for the classical 5-nitrofurans tested there is a tendency towards a dose-related increase of the DNA damage in the comet assay and the observed increases for the parameters analysed (Olive tail moment, tail % DNA and tail length) were significant for all compounds. Then, the four 5-nitrofurans tested were considered genotoxic. These results show that the position of the nitro group influences the genotoxicity of the assayed compounds. Thus, in this comet assay, the 2-furylethylene derivatives having the nitro group attached outside the furan ring appear to be much less genotoxic than the 5-nitrofurans.

Cytogenetic study of metronidazole and three metronidazole analogues in cultured human lymphocytes with and without metabolic activation

Metronidazole (MTZ) and other nitroimidazole derivatives have been extensively used to treat infections caused by protozoa and anaerobic bacteria. However, the need for new derivatives with similar therapeutic activity but lower toxicity to human beings prevails. On this purpose, three metronidazole analogues were synthesized, namely: 1-(p-methylphenacyl)-2-methyl-4-nitro imidazole (CPMe), 1-(p-methoxyphenacyl)-2-methyl-4-nitroimidazole (CPMeO), and 1-(p-fluorphenacyl)-2-methyl-4-nitroimidazole (CPF), which at low concentrations (0.5-2 microg/ml) showed a higher activity against Entamoeba histolytica than MTZ (3-6 microg/ml). The aim of this work was to investigate the cytogenetic effect of the three MTZ analogues on human lymphocyte cultures with and without metabolic activation in vitro, using the sister chromatid exchange test (SCE), comparatively with MTZ. The effect of the compounds on the cell proliferation kinetics (CPK) measured by the replication index (RI) and the cytotoxic effect in the mitotic index (MI) was evaluated as well. The SCE frequencies with and without S9 metabolic activation in treated and control lymphocytes showed no significant statistical differences. However when metabolic activation was involved a significant increase in the amount of third division metaphases provoked the CPK increased significantly with all the tested compounds. The RI showed similar behaviour, except for compound CPF.