Colloidal bismuth pectin: an alternative to bismuth subcitrate for the treatment of Helicobacter pylori--positive duodenal ulcer

A Transformable Mucoadhesive Microgel Network for Noninvasive Multimodal Imaging And Radioprotection of a Large Area of the Gastrointestinal Tract

The lack of noninvasive imaging and modulation of a large area of the gastrointestinal (GI) tract constrain the diagnosis and treatment of many GI-related diseases. Recent advances use novel mucoadhesive materials to coat a part of the GI tract and then modulate its functions. High mucoadhesion is the key factor of the partial coating, but also the limitation for not spreading and covering the lower GI tract. Here, a bismuth-pectin organic-inorganic hybrid complex is screened and engineered into a transformable microgel network (Bi-GLUE) with high flowability and mucoadhesion, such that it can quickly transit through and coat a large area of the GI tract. In murine and porcine models, Bi-GLUE delivers contrast agents to achieve real-time, large-area GI-tract imaging under X-ray or magnetic resonance  modalities and to facilitate the non-invasive diagnosis of familial adenomatous polyposis. Moreover, Bi-GLUE, like an intracorporal radiation shield, decreases the radiotoxicity in a whole-abdomen irradiation rat model. This transformable microgel network offers a new direction that can modulate a large area of the GI tract and may have broad applications for GI-related conditions.

Colloidal bismuth pectin-containing quadruple therapy as the first-line treatment of Helicobacter pylori infection: A multicenter, randomized, double-blind, non-inferiority clinical trial

BACKGROUND

Bismuth-containing quadruple therapy is an effective regimen for Helicobacter pylori (H. pylori) treatment. No head-to-head comparison trials have been conducted to evaluate the efficacy of colloidal bismuth pectin (CBP) in quadruple therapy for eradicating H. pylori. We aimed to compare the efficacy and safety of CBP quadruple therapy and bismuth potassium citrate (BPC) quadruple therapy for 14 days in the first-line treatment of H. pylori.

METHODS

In this multicenter, randomized, double-blind, non-inferiority clinical trial, H. pylori-infected subjects without eradication history were randomized to receive amoxicillin 1 g twice daily, tetracycline 500 mg three time daily, esomeprazole 20 mg twice daily in combination with CBP 200 mg three time daily or BPC 240 mg twice daily for 14 days. ¹³ C-urea breath tests were used to access the eradication rate at least 4 weeks after treatment.

RESULTS

Between April 2021 and July 2022, 406 patients were assessed for eligibility and 339 subjects were randomized. The cure rates (primary outcome) of CBP and BPC quadruple therapy were 90.5% and 92.3% (p = 0.56) by intention-to-treat analysis, respectively, and 96.1% and 96.2% (p = 1.00) by per-protocol analysis, respectively. CBP quadruple therapy was non-inferior to BPC quadruple therapy in the intention-to-treat and per-protocol analysis (p < 0.025). The frequency of adverse events and compliance were not different among the two groups (p > 0.05).

CONCLUSIONS

Both CBP and BPC quadruple therapy for 14 days provide high efficacy, good compliance, and safety in the first-line treatment of H. pylori in China.

Medicinal chemistry and biomedical applications of bismuth-based compounds and nanoparticles

Bismuth as a relatively non-toxic and inexpensive metal with exceptional properties has numerous biomedical applications. Bismuth-based compounds are used extensively as medicines for the treatment of gastrointestinal disorders including dyspepsia, gastric ulcers and H. pylori infections. Recently, its medicinal application was further extended to potential treatments of viral infection, multidrug resistant microbial infections, cancer and also imaging, drug delivery and biosensing. In this review we have highlighted the unique chemistry and biological chemistry of bismuth-209 as a prelude to sections covering the unique antibacterial activity of bismuth including a description of research undertaken to date to elucidate key molecular mechanisms of action against H. pylori, the development of novel compounds to treat infection from microbes beyond H. pylori and the significant role bismuth compounds can play as resistance breakers. Furthermore we have provided an account of the potential therapeutic application of bismuth-213 in targeted alpha therapy as well as a summary of the biomedical applications of bismuth-based nanoparticles and composites. Ultimately this review aims to provide the state of the art, highlight the untapped biomedical potential of bismuth and encourage original contributions to this exciting and important field.

Cost-effectiveness analysis of two routine therapeutic methods for Helicobacter pylori eradication: a Persian cohort-based study

AIM

This study aimed to analyze the cost-effectiveness of two routine therapeutic methods for H. pylori eradication in Iran.

BACKGROUND

Because of the importance of Helicobacter pylori (H. pylori) eradication on gastric cancer prevalence and costs, an economic analysis of the eradication methods is essential for health systems.

METHODS

This cross-sectional study was conducted on 7,496 participants with positive Hepadnaviridae (HPsAg) test results for H. pylori; 6,163 of them were treated with furazolidone (group A), and 1,333 participants were treated with clarithromycin (group B). Data on GP visits, medications, and HPsAg costs as direct costs and absence from work and transportation as indirect costs was collected by researcher-made questionnaire. Indirect costs were calculated based on face-to-face interviews with 365 patients of the Persian Cohort Center. Successful eradication of H. pylori infection (negative HPsAg) was defined as the effectiveness of the interventions. Incremental cost-effectiveness ratio (ICER) was used to compare the overall results.

RESULTS

The total direct cost of H. pylori for groups A and B were estimated at 13.7 and 5.83 billion IRR, respectively. The highest and lowest percentages of total costs were the cost of diagnostic services and the time cost, respectively. There was a significant difference between the two groups in drug costs (p<0.001). The effect ratio for groups A and B was 85.93% and 96.54%, respectively. Cost per effectiveness was higher for clarithromycin (CE=3,250,170 IRR) than for furazolidone (CE=2,988,488 IRR), and ICER showed that 5.1 Million IRR per participant is needed to eradicate H. pylori.

CONCLUSION

Based on the results, furazolidone was more cost-effective than clarithromycin for H. pylori treatment. Therefore, due to the high prevalence of H. pylori and the economic conditions of the health system in Iran, furazolidone can be a cost-effective choice between the two conventional treatment methods considering the results of further research and possible side effects.

Role of bismuth in improving Helicobacter pylori eradication with triple therapy

In most regions of the world, antimicrobial resistance has increased to the point where empirical standard triple therapy for Helicobacter pylorieradication is no longer recommended. The treatment outcome in a population is calculated as the sum of the treatment success in the subpopulation with susceptible infections plus treatment success in the subpopulation with resistant infections. The addition of bismuth (i.e., 14-day triple therapy plus bismuth) can improve cure rates despite a high prevalence of antimicrobial resistance. The major bismuth effect is to add an additional 30%-40% to the success with resistant infections. The overall result is therefore dependent on the prevalence of resistance and the treatment success in the subpopulation with resistant infections (eg, with proton-pump inhibitor-amoxicillin dual therapy). Here, we explore the contribution of each component and the mechanisms of how bismuth might enhance the effectiveness of triple therapy. We also discuss the limitations of this approach and provide suggestions how triple therapy plus bismuth might be further improved.

Polypotency of the immunomodulatory effect of pectins

Pectins are the major component of plant cell walls, and they display diverse biological activities including immunomodulation. The pectin macromolecule contains fragments of linear and branched regions of polysaccharides such as homogalacturonan, rhamnogalacturonan-I, xylogalacturonan, and apiogalacturonan. These structural features determine the effect of pectins on the immune system. The backbones of pectic macromolecules have immunosuppressive activity. Pectins containing greater than 80% galacturonic acid residues were found to decrease macrophage activity and inhibit the delayed-type hypersensitivity reaction. Branched galacturonan fragments result in a biphasic immunomodulatory action. The branched region of pectins mediates both increased phagocytosis and antibody production. The fine structure of the galactan, arabinan, and apiogalacturonan side chains determines the stimulating interaction between pectin and immune cells. This review summarizes data regarding the relationship between the structure and immunomodulatory activity of pectins isolated from the plants of the European north of Russia and elucidates the concept of polypotency of pectins in native plant cell walls to both stimulate and suppress the immune response. The possible mechanisms of the immunostimulatory and anti-inflammatory effects of pectins are also discussed.

Gastroprotective effect of natural non-starch polysaccharides

Experiments on mice and rats with modeled neurogenic and indomethacin-induced injuries to the gastric mucosa showed that preventive courses of calcium alginate, calcium pectate, and low-esterified pectin improved the resistance of the gastroduodenal mucosa to the destructive effect of the above factors.

Meta-analysis: the efficacy, adverse events, and adherence related to first-line anti-Helicobacter pylori quadruple therapies

BACKGROUND

Owing to rising drug-resistant Helicobacter pylori infections, currently recommended proton-pump inhibitor-based triple therapies are losing their efficacy, and regimens efficacious in the presence of drug resistance are needed.

AIMS

To summarize the efficacy, safety and adherence of first-line quadruple H. pylori therapies in adults.

METHODS

Meta-regression models identified factors explaining variation in the efficacy of first-line quadruple therapies from 145 treatment arms. Estimates of average efficacy were calculated within homogeneous groups.

RESULTS

Quadruple therapy containing a gastric acid inhibitor, bismuth, metronidazole and tetracycline was enhanced when omeprazole was included, treatment duration lasted 10-14 days, and when therapy took place in the Netherlands, Hong Kong and Australia. Treatment efficacy decreased as the prevalence of metronidazole resistance increased. Even in areas with a high prevalence of metronidazole resistance, this quadruple regimen eradicated more than 85% of H. pylori infections when it contained omeprazole and was given for 10-14 days. Furthermore, in the presence of clarithromycin resistance, this quadruple regimen eradicated 90-100% of H. pylori infections, while the currently recommended triple therapy containing clarithromycin, amoxicillin and a proton-pump inhibitor eradicated only 25-61% (P < 0.001). Adherence and adverse events for quadruple therapy were similar to currently recommended triple therapies.

CONCLUSIONS

Guidelines should include quadruple therapy with a proton-pump inhibitor, a bismuth compound, metronidazole and tetracycline among recommended first-line anti-H. pylori therapies.

Double-blind comparison of absorbable colloidal bismuth subcitrate and nonabsorbable bismuth subnitrate in the eradication of Helicobacter pylori and the relief of nonulcer dyspepsia

BACKGROUND

Bismuth is widely used for the eradication of H. pylori, especially in developing countries, although there are concerns over its neurotoxicity. Whether bismuth has to be absorbed in humans to act against H. pylori is not known. In this study, we compared "absorbable" (colloidal bismuth subcitrate) and "nonabsorbable" (bismuth subnitrate) bismuth as part of triple therapy in the eradication of H. pylori.

MATERIALS AND METHODS

A double-blind, randomized, placebo-controlled trial was carried out with 120 H. pylori-positive patients with nonulcer dyspepsia. Group CBS + Ab (n = 35) received colloidal bismuth subcitrate (one tablet qds), amoxicillin (500 mg qds), and metronidazole (400 mg tds). Group BSN + Ab (n = 35) received bismuth subnitrate (two tablets tds) and the same antibiotics. Group Ab (n = 35) received placebo bismuth (two tablets tds) and the antibiotics. Group BSN (n = 15) received bismuth subnitrate (two tablets tds) and placebo antibiotics. Bismuth was taken for 4 weeks and the antibiotics for the first 2 weeks. H. pylori eradication, side effects, compliance, pre- and post-treatment symptom scores, and bismuth absorption were assessed.

RESULTS

H. pylori eradication was 69%, 83%, 31%, and 0% in CBS + Ab, BSN + Ab, Ab, and BSN, respectively. Side effects, compliance, and symptom relief were similar in all groups, but blood bismuth levels were significantly greater in CBS + Ab than the other three groups.

CONCLUSION

The efficacy of bismuth-based therapies as part of triple therapy in the eradication of H. pylori is unrelated to absorption. Hence, the use of effective but poorly absorbed bismuth preparations should be encouraged for bismuth-based eradication therapies.