Allosteric inhibition of SARS-CoV-2 3CL protease by colloidal bismuth subcitrate

Colloidal bismuth subcitrate (CBS) is an allosteric inhibitor of 3-chymotrypsin-like protease (3CLpro) in SARS-CoV-2. CBS binding causes dimeric 3CLpro dissociation and proteolytic dysfunction, leading to the suppression of SARS-CoV-2 replication.

INFLUENCE OF SYSTEMATIC TAKING BLOCKERS OF H2-HISTAMINE RECEPTORS ON THE DEGREE OF SEMINATION OF GASTRIC MUCOSA WITH HELICOBACTER PYLORI INFECTION OF PATIENT WITH CHRONIC NON – ATROPHIC GASTRITIS

The aim: To determine the effect of prolonged use of H2-histamine receptor blockers on the degree of contamination of the gastric mucosa with HP infection in patients with chronic non-atrophic gastritis. Materials and methods: 28 patients with chronic atrophic gastritis (the main group), who regularly took H2-histamine receptor blockers for 2 to 7 years, and 30 patients (control group), who never used them were comprehensively examined. Comprehensive examination included: step-by-step intragastric pH-metry, esophagogastroduodenoscopy, helicobacter infection test (НР) (helicobacter urease test and microscopic examination of stained smears), histological investigations of the gastric stump mucous, material for which was taken during endoscopy from 4 topographical zones: from the middle third of the gastric antrum and body of stomach on the big and small curvature. Results: All the patients in 100% of cases have confirmed the existence of chronic non-atrophic gastritis in both active and inactive stages of varying degrees of severity. Helicobacter infection was detected in 100% of cases. A comparative analysis of the data on the average degree of infection of the gastric mucosa by HP infection in the same topographic zones in the patients of the main and control groups revealed a significant (p <0.05) higher degree of seeding of the gastric mucosa in patients of the main group in all zones. Conclusions: Monotherapy for chronic non-atrophic gastritis with blockers of Н2-histamine receptors leads to an increase in the degree of gastric mucosa semination with HP infection. This fact requires mandatory parallel use of antibacterial agents – colloidal bismuth subcitrate and antibiotics, with blockers of Н2-histamine receptors.

Exposure and nephrotoxicity concern of bismuth with the occurrence of autophagy

Metal nanoparticles or metal-based compounds have drawn attention in various fields ranging from industry to medicine because of their unique physicochemical properties. Bismuth (Bi) compounds and nanomaterials have been commonly used in alloys, electronic industry, batteries, and as flame retardants as well as for anti- Helicobacter pylori therapy, while the nanomaterial form has great potential for computed tomography imaging and thermotherapy, both of which will be introduced in this review. Although Bi was used for several decades, there is a lack of detailed information concerning their toxicity and mechanisms on human health. We described the toxicity of Bi on the kidney that seemed to be relatively known by researchers, while the mechanisms remain unclear. Recently, our group has found that Bi compounds, including bismuth nitrate (BN) and Bi nanomaterials, can induce autophagy in kidney cells. We also extended our findings by selecting five Bi compounds, and the results showed that BN, bismuth oxychloride, bismuth citrate, colloidal bismuth subcitrate, and Bi nanomaterials all induced slight cytotoxicity accompanied with autophagy. Although the role of autophagy in Bi-induced cytotoxicity and kidney injury is under investigation by us, autophagy may help with the exploration of the mechanisms of nephrotoxicity by Bi.

Efficacy and Safety of Wei Bi Mei, a Chinese Herb Compound, as an Alternative to Bismuth for Eradication of Helicobacter pylori

Bismuth-containing quadruple therapy has been recommended as the first line of treatment in areas of high clarithromycin or metronidazole resistance. However, safety concerns of bismuth agents have long been raised. We first assessed the efficacy and safety of Wei Bi Mei granules, which are bismuth compounds consisting of three synthetic drugs and five medicinal herbs, compared to bismuth aluminate and colloidal bismuth subcitrate (CBS) in H. pylori-infected mouse model. We then used atomic fluorescence spectroscopy and autometallography to measure the accumulation of three bismuth agents in the brain, heart, liver, and kidneys in adult Sprague-Dawley rats. We also evaluated the safety of bismuth agents by conducting clinical biochemistry tests in blood samples of experimental animals. Wei Bi Mei granules exhibited the highest efficacy of anti-H. pylori activity and yielded the lowest bismuth accumulation when compared to CBS and bismuth aluminate. Our findings show that Wei Bi Mei granules are a safe Chinese medicinal herb with potent anti-H. pylori activity and can be considered as an alternative to current bismuth compounds. Thus, Wei Bi Mei granules merit further evaluation, particularly with regard to efficacy and safety when they are combined with other H. pylori eradication medications in the clinical setting.

THE EFFICACY OF THE BISMUTH-CONTAINING QUADRUPLE REGIMEN IN HELICOBACTER PYLORI INFETION

Background and Objectives: Bismuth-containing quadruple regimen is recommended as an first-line therapy in areas with high clarithromycin and metronidazole resistance as well as an option for patients who have previously failed to respond to Helicobacter pylori eradication therapy. There have been very few researches on the effectiveness of this regimen on Helicobacter pylori infection treatment in our country. The our study aimed to show the efficacy of Bismuth-based therapy for the treatment of Helicobacter pylori infection. Patients and Methods: The study was carried out on 196 patients with Helicobacter pylori infection. All of patients received a quadruple therapy consisted of Rapeprazole 20 mg bid, Colloidal bismuth subcitrate 120mg qid, Tetracycline 500mg qid and Metronidazole 500mg tid for 14 days. The diagnosis of Helicobacter Pylori infection was performed by Clotest or C13 urea-breath test. Four to eight weeks after completion of therapy, Helicobacter pylori status was rechecked by Clotest or C13 urea-breath test. Results: A total of 196 patients with Helicobacter pylori infection were recruited. The eradication rates of the Bismuth-containing quadruple regimen overall, fornaïve,previously failed to respond to Helicobacter pylori eradication therapy on intention to treat (ITT) and per-protocol (PP) analysis were 97.4-97.3%; 98.3-98.1% and 96.3-96.2%. Side effects occurred in 80.5% of subjects. The common side effects were fatigue, anorexia and nausea. The compliancerate was 98.4%. Conclusions: Bismuth-containing quadruple regimen achieved very highe radication rates. Side effects were common but not serious. The medication adherence rate was high. Key words: Bismuth-containing quadruple regimen, eradication, Helicobacter pylori infection