Equivalence Trial of the Non-Bismuth 10-Day Concomitant and 14-Day Hybrid Therapies for Helicobacter pylori Eradication in High Clarithromycin Resistance Areas

Background and aim: We conducted an equivalence trial of quadruple non-bismuth "concomitant" and "hybrid" regimens for H. pylori eradication in a high clarithromycin resistance area. Methods: There were 321 treatment-naïve H. pylori-positive individuals in this multicenter clinical trial randomized to either the hybrid (esomeprazole 40 mg/bid, amoxicillin 1 g/bid for 7 days, then 7 days esomeprazole 40 mg/bid, amoxicillin 1 g/bid, clarithromycin 500 mg/bid, and metronidazole 500 mg/bid) or the concomitant regimen (all medications given concurrently bid for 10 days). Eradication was tested using histology and/or a 13C-urea breath test. Results: The concomitant regimen had 161 patients (90F/71M, mean 54.5 years, 26.7% smokers, 30.4% ulcer) and the hybrid regimen had 160 (80F/80M, mean 52.8 years, 35.6% smokers, 31.2% ulcer). The regimens were equivalent, by intention to treat 85% and 81.8%, (p = 0.5), and per protocol analysis 91.8% and 87.8%, (p = 0.3), respectively. The eradication rate by resistance, between concomitant and hybrid regimens, was in susceptible strains (97% and 97%, p = 0.6), clarithromycin single-resistant strains (86% and 90%, p = 0.9), metronidazole single-resistant strains (96% and 81%, p = 0.1), and dual-resistant strains (70% and 53%, p = 0.5). The side effects were comparable, except for diarrhea being more frequent in the concomitant regimen. Conclusions: A 14-day hybrid regimen is equivalent to a 10-day concomitant regimen currently used in high clarithromycin and metronidazole resistance areas. Both regimens are well tolerated and safe.

Real-time PCR detection of Helicobacter pylori clarithromycin resistance in Thrace, Greece

BACKGROUND

Growing resistance to clarithromycin is a major concern regarding treating Helicobacter pylori (H. pylori) infection. Resistance rates have a great variation even in different geographic areas within the same country and are associated with point mutations of the microbial 23S rRNA (A2142C, A2142G, and A2143G). Given the absence of available data in Thrace, the objective of this study was to estimate the resistance of H. pylori to clarithromycin and identify specific mutations that contribute to clarithromycin resistance.

METHODS

In this prospective study, we enrolled consecutive patients referred for dyspeptic complaints who underwent upper gastrointestinal endoscopy over two years. Gastric biopsies from corpus and antrum were initially tested for the presence of urease by a rapid urease test. Urease positive samples were followed by real-time PCR to confirm the presence of H. pylori and to detect point mutations.

RESULTS

A total of one hundred and thirty patients were included in the study (72 women and 58 men). Resistance to clarithromycin was detected at 23.2 %. Neither gender nor age was independently correlated with resistance rate in our patient group. The most common mutations were A2142G and A2143G.

CONCLUSIONS

A high rate of H. pylori resistance to clarithromycin was observed in our region, implicating that it should be addressed in accordance with the recommendations provided by national and international guidelines. Molecular testing should be considered an integral tool for effective monitoring in case of suspected antibiotic resistance. HIPPOKRATIA 2021, 25 (2):51-55.

Randomized clinical trial comparing ten day concomitant and sequential therapies for Helicobacter pylori eradication in a high clarithromycin resistance area

BACKGROUND

Currently only a few studies compare sequential and concomitant non-bismuth Helicobacter pylori therapies referring to high antibiotic resistance populations.

MATERIALS AND METHODS

This multicenter prospective randomized clinical trial included 353 H. pylori positive, treatment naïve, patients. All patients had positive CLO-test and/or histology and culture. They received sequential (esomeprazole 40mg, amoxicillin 1g/bid for 5days, followed by 5days of esomeprazole 40mg, clarithromycin 500mg and metronidazole 500mg bid), or concomitant treatment (all drugs taken concomitantly bid for 10days). Eradication was confirmed by (13)C-urea breath test or histology 4-6weeks after treatment. Adverse events and adherence were evaluated.

RESULTS

Allocated to concomitant were 175 (72F/103M, mean 52.3years, 38.3% smokers, 25.7% ulcer disease) and 178 (87F/91M, mean 52years, 31% smokers, 19.1% ulcer disease) patients to sequential treatment. There were 303/353 (85.8%) positive cultures, with the following resistances: 34% metronidazole, 27.7% clarithromycin, and 7.9% dual. Eradication rates were, respectively, 89.1% (156/175) vs. 78.7% (140/178) by intention to treat (p=0.01, 95% CI=2.7-18) and 93.4%(156/167) vs. 82.8% (140/169) per protocol (p=0.004, 95% CI=3.6-17.6). Overall, adherence was (98.9%, 95% CI=97-100). Eradication rates according to resistance were the following: dual susceptible strains 67/69 (97.1%), 62/67 (92%) (p=0.4), metronidazole single resistant 38/39 (97.4%), 31/39 (79.5%) (p=0.03, 95% CI=3.5-33), clarithromycin single resistant 25/28 (89.3%), 26/31 (83.9%) (p=0.8), and dual resistant 9/12 (75%), 4/11 (36.4%) (p=0.1) for concomitant and sequential regimens, respectively. Side effects were comparable among regimens, except from diarrhea being more frequent among patients treated with concomitant treatment.

CONCLUSIONS

Concomitant treatment eradication rate overcomes 90% per protocol and has a significant advantage over sequential therapy. This is probably due to its better efficacy on metronidazole resistant strains. Both regimens were well tolerated and safe.

In vitro and in vivo inhibition of Helicobacter pylori by Lactobacillus casei strain Shirota

We studied the potential inhibitory effect of Lactobacillus casei strain Shirota (from the fermented milk product Yakult [Yakult Ltd., Tokyo, Japan]) on Helicobacter pylori by using (i) in vitro inhibition assays with H. pylori SS1 (Sydney strain 1) and nine H. pylori clinical isolates and (ii) the in vivo H. pylori SS1 mouse model of infection over a period of 9 months. In vitro activity against H. pylori SS1 and all of the clinical isolates was observed in the presence of viable L. casei strain Shirota cells but not in the cell-free culture supernatant, although there was profound inhibition of urease activity. In vivo experiments were performed by oral administration of L. casei strain Shirota in the water supply over a period of 9 months to 6-week-old C57BL/6 mice previously infected with H. pylori SS1 (study group; n = 25). Appropriate control groups of H. pylori-infected but untreated animals (n = 25) and uninfected animals given L. casei strain Shirota (n = 25) also were included in the study. H. pylori colonization and development of gastritis were assessed at 1, 2, 3, 6, and 9 months postinfection. A significant reduction in the levels of H. pylori colonization was observed in the antrum and body mucosa in vivo in the lactobacillus-treated study group, as assessed by viable cultures, compared to the levels in the H. pylori-infected control group. This reduction was accompanied by a significant decline in the associated chronic and active gastric mucosal inflammation observed at each time point throughout the observation period. A trend toward a decrease in the anti-H. pylori immunoglobulin G response was measured in the serum of the animals treated with lactobacillus, although this decrease was not significant.

Transcriptional repressor ERF is a Ras/mitogen-activated protein kinase target that regulates cellular proliferation

A limited number of transcription factors have been suggested to be regulated directly by Erks within the Ras/mitogen-activated protein kinase signaling pathway. In this paper we demonstrate that ERF, a ubiquitously expressed transcriptional repressor that belongs to the Ets family, is physically associated with and phosphorylated in vitro and in vivo by Erks. This phosphorylation determines the ERF subcellular localization. Upon mitogenic stimulation, ERF is immediately phosphorylated and exported to the cytoplasm. The export is blocked by specific Erk inhibitors and is abolished when residues undergoing phosphorylation are mutated to alanine. Upon growth factor deprivation, ERF is rapidly dephosphorylated and transported back into the nucleus. Phosphorylation-defective ERF mutations suppress Ras-induced tumorigenicity and arrest the cells at the G0/G1 phase of the cell cycle. Our findings strongly suggest that ERF may be important in the control of cellular proliferation during the G0/G1 transition and that it may be one of the effectors in the mammalian Ras signaling pathway.

A polymer-Triton X-100 conjugate capable of PH-dependent red blood cell lysis: a model system illustrating the possibility of drug delivery within acidic intracellular compartments

Poly(amidoamines) are soluble polymers containing tertiary amino and amido groups regularly arranged along the macromolecular chain, and their net average charge alters considerably as pH changes from neutral to acidic leading to a change in conformation. This property provides the possibility to design polymer-drug conjugates that are, following intravenous administration, relatively compacted and thus protect a drug payload in the circulation, but following pinocytic internalisation into acidic intracellular compartments unfold permitting pH-triggered intracellular drug delivery. To study the feasibility of this approach, a covalent conjugate of a poly(amidoamine) (MBI) was prepared to contain the membrane lytic non-ionic detergent Triton X-100 (as a model), and its ability to lyse red blood cells in vitro was used as an indicator of conjugate conformation at at different pHs. Although Triton X-100 was highly lytic at pH 5.5, 7.4 and 8.0, and the parent polymer MBI was not lytic under any conditions, the conjugate only showed concentration-dependent red blood cell lysis at pH 5.5. Moreover, incubation of human leukaemic cells (CCRF) with these substrates showed conjugate to be more toxic than MBI (IC50 values of 100 micrograms/ml and 650 micrograms/ml respectively) and less toxic than Triton X-100 (IC50 of 1 microgram/ml).

Poly(amidoamine)s with potential as drug carriers: degradation and cellular toxicity

Poly(amidoamine)s were synthesized by polyaddition reaction: to bis-acryloylpiperazine of piperazine (1), or N,N'-bis(2-hydroxyethyl)ethylenediamine (2), and to 2,2-bis(acrylamido)acetic acid of piperazine (3). Compound 2 was also end-capped with 4-hydroxythiophenol, thus introducing a terminal moiety suitable for radio-iodination using the chloramine T method (4). Such polymers behave as bases in aqueous solution, and their net average charge alters considerably as the pH changes from 7.4 to 5.5. This results in a change in polymer conformation which may prove useful in the design of polymeric drug delivery systems. However, their suitability for use in the organism will depend on polymer toxicity and also on their rate of biodegradation. Here we studied the biological properties of the above poly(amidoamine)s with a view to optimizing the synthesis of novel drug carriers. The general cytotoxicity of compounds 1, 2, 3, and 4 was examined in vitro using two human cell lines, hepatoma (HepG2) and a lymphoblastoid leukaemia (CCRF). Several different methods [the tetrazolium (MTT) test, [3H]leucine or [3H]thymidine incorporation, or counting cell numbers] were used to measure cell viability. Compounds 1, 2, and 4 were much less toxic to both cell lines than equivalent concentrations of the polycationic poly-L-lysine, and in no case did viability fall below 50% (concentrations up to 2 mg/ml). Although compound 2 was not markedly toxic to HepG2 cells, concentration-dependent toxicity was observed against CCRF cells. In this case, the polymer concentration decreasing viability by 59% (ID50) was approximately 50 micrograms/ml for compound 2 compared with an ID50 of approximately 10 micrograms/ml for poly-L-lysine. The rate of hydrolytic degradation of compound 2 was examined using viscometric measurements and gel permeation chromatography (GPC). After incubation at pH 7.5 and 8.0 for 24 h, polymer intrinsic viscosity was decreased by approximately 50% and GPC elution profiles showed a simultaneous increase in polymer retention time, indicating a fall in molecular weight. Hydrolytic degradation progressed much more slowly at pH 5.5. Compound 4 was also incubated with a mixture of isolated rat liver lysosomal enzymes (tritosomes) at pH 5.5, but no increase in the rate of degradation was observed.