ABSTRACT
Background: The ideal combination regimen for Helicobacter pylori (HP) eradication has not yet been determined and the success rate of HP eradication has been extensively reduced worldwide due to increasing antibiotic resistance. So this multinational multi-center randomized controlled trial was designed to evaluate the efficacy of tetracycline +levofloxacin for HP eradication. Methods: During a 6-month period, all of the cases with HP infection in eight referral tertiary centers of three countries were included and randomly allocated to receive either tetracycline + levofloxacin or clarithromycin plus amoxicillin quadruple regimen for two weeks. For all of the participants, pantoprazole was continued for 4 more weeks and after one to two weeks of off-therapy, they underwent urea breath test C13 to prove eradication. Results: Overall 788 patients were included (358 male (45.4%), average age 44.2 years). They were diagnosed as having non-ulcer dyspepsia (516 cases, 65.5%), peptic ulcer disease (PUD) (234 cases, 29.69%), and intestinal metaplasia (38 cases, 4.8%). Racially 63.1% were Caucasian, 14.5% Arab, 15.6% African, and 6.1% Asian. The participants were randomly allocated to groups A and B to receive either tetracycline + levofloxacin or clarithromycin. Among groups A and B in intention to treat (ITT) and per protocol (PP) analysis, 75.2% & 82.1% (285 cases) and 67.5% & 70.1% (276 cases) of participants achieved eradication, respectively (P = 0.0001). The complete compliance rate in groups A and B were 84.4% and 83.6%, respectively. During the study, 33.5% of the participants in group A (127 cases) reported side effects while the complication rate among group B was 27.9% (114 cases, P = 0.041). The most common complaints among groups A and B were nausea and vomiting (12.6% & 9.3%) and abdominal pain (4.48% & 2.68%), respectively. The rate of severe complications that caused discontinuation of medication in groups A and B were 2.1% and 1.46%, respectively (P = 679). In subgroup analysis, the eradication rates of tetracycline+levofloxacin among patients with non-ulcer dyspepsia, PUD, and intestinal metaplasia were 79.4%, 88.1%, and 73.9%, respectively. These figures in group B (clarithromycin base) were 71.3%, 67.6%, and 61.5% respectively (P = 0.0001, 0.0001, and 0.043). Conclusion: Overall, the combination of tetracycline+levofloxacin is more efficient for HP eradication in comparison with clarithromycin+amoxicillin despite more complication rate. In areas with a high rate of resistance to clarithromycin, this therapeutic regimen could be an ideal choice for HP eradication, especially among those who were diagnosed with PUD.
ABSTRACT
BACKGROUND: Hypomethylation of long interspersed nuclear element 1 (LINE-1) is characteristic of various cancer types, including colorectal cancer (CRC). Malfunction of several factors or alteration of methyl-donor molecules' (folic acid and S-adenosylmethionine) availability can contribute to DNA methylation changes. Detection of epigenetic alterations in liquid biopsies can assist in the early recognition of CRC. Following the investigations of a Hungarian colon tissue sample set, our goal was to examine the LINE-1 methylation of blood samples along the colorectal adenoma-carcinoma sequence and in inflammatory bowel disease. Moreover, we aimed to explore the possible underlying mechanisms of global DNA hypomethylation formation on a multi-level aspect. METHODS: LINE-1 methylation of colon tissue (n = 183) and plasma (n = 48) samples of healthy controls and patients with colorectal tumours were examined with bisulfite pyrosequencing. To investigate mRNA expression, microarray analysis results were reanalysed in silico (n = 60). Immunohistochemistry staining was used to validate DNA methyltransferases (DNMTs) and folate receptor beta (FOLR2) expression along with the determination of methyl-donor molecules' in situ level (n = 40). RESULTS: Significantly decreased LINE-1 methylation level was observed in line with cancer progression both in tissue (adenoma: 72.7 ± 4.8%, and CRC: 69.7 ± 7.6% vs. normal: 77.5 ± 1.7%, p ≤ 0.01) and liquid biopsies (adenoma: 80.0 ± 1.7%, and CRC: 79.8 ± 1.3% vs. normal: 82.0 ± 2.0%, p ≤ 0.01). However, no significant changes were recognized in inflammatory bowel disease cases. According to in silico analysis of microarray data, altered mRNA levels of several DNA methylation-related enzymes were detected in tumours vs. healthy biopsies, namely one-carbon metabolism-related genes-which met our analysing criteria-showed upregulation, while FOLR2 was downregulated. Using immunohistochemistry, DNMTs, and FOLR2 expression were confirmed. Moreover, significantly diminished folic acid and S-adenosylmethionine levels were observed in parallel with decreasing 5-methylcytosine staining in tumours compared to normal adjacent to tumour tissues (p ≤ 0.05). CONCLUSION: Our results suggest that LINE-1 hypomethylation may have a distinguishing value in precancerous stages compared to healthy samples in liquid biopsies. Furthermore, the reduction of global DNA methylation level could be linked to reduced methyl-donor availability with the contribution of decreased FOLR2 expression.
