Evaluation of the effects of a proton pump inhibitor on Helicobacter pylori stool antigen testing

BACKGROUND

Some patients find it difficult to discontinue proton pump inhibitors (PPIs). Unlike the ¹³ C-urea breath test (UBT), the stool antigen test (SAT), particularly when domestically produced kits are used, may be less likely to yield false-negative results.

METHODS

This prospective study included a convenience series of 35 healthy Japanese subjects. Based on a statistical calculation, acceptable numbers of subjects were considered at least 21 and 11 with and without Helicobacter pylori (H. pylori) infection, respectively. The H. pylori infection was determined using the UBT or rapid urease test. SATs were performed with three novel domestically produced kits (the rapid immunochromatography tests Quick Navi™-H. pylori [Navi™] and Quick Chaser® H. pylori [Chaser®], and the bioluminescent enzyme immunoassay test BLEIA® 'EIKEN' H. pylori Antigen [BLEIA®]) before and after oral PPI administration (30 mg lansoprazole once daily for 14 days). For each kit, the sensitivities and specificities were calculated and compared before and after PPI administration. Furthermore, the cutoff index (COI) values of BLEIA® before and after PPI administration were compared in H. pylori-infected subjects.

RESULTS

H. pylori infection was detected in 68.6% (24/35) of the included subjects. The sensitivities and specificities before versus after PPI administration were as follows: 79.2% (19/24) and 100.0% (11/11) versus 75.0% (18/24) and 100.0% (11/11) for Navi™, respectively (p = 1); 87.5% (21/24) and 100.0% (11/11) versus 75.0% (18/24) and 100.0% (11/11) for Chaser®, respectively (p = .371); 100.0% (24/24) and 100.0% (11/11) versus 95.8% (23/24) and 100.0% (11/11) for BLEIA®, respectively (p = 1). The median COI values of BLEIA® before and after PPI administration were 1389.0 and 3207.25, respectively (p = .0839).

CONCLUSIONS

In stool specimens, H. pylori antigenicity is maintained even during PPI use. SAT using a bioluminescent enzyme immunoassay is particularly recommended because of its extremely high sensitivity.

Analysis of the cost-effectiveness of using vonoprazan-amoxicillin-clarithromycin triple therapy for first-line Helicobacter pylori eradication

BACKGROUND

Vonoprazan (VPZ)-based triple therapy has been reported to have greater efficacy than a proton pump inhibitor (PPI)-based triple therapy for Helicobacter pylori (H. pylori) eradication. However, because VPZ is more expensive than PPIs such as rabeprazole (RPZ), economic evaluation is essential.

METHODS

We performed a retrospective study on 209 patients who underwent first-line eradication of H. pylori infection in Fuyoukai Murakami Hospital from 1 March 2015 to 31 March 2016. Patients who received VPZ, amoxicillin (AMPC) and clarithromycin (CAM) were assigned to the VPZ/AC group (n = 111) and patients who received RPZ, AMPC and CAM to the RPZ/AC group (n = 98). We compared the patients' backgrounds, including age, gender, use of high-dose CAM, past history of peptic ulcer, smoking and drug-related adverse events between the two groups. We defined cost as direct medical costs per patient and effectiveness as the first-line eradication rate in the intention-to-treat (ITT) analysis and analyzed the cost-effectiveness using the cost-effectiveness ratio (CER) and incremental cost-effectiveness ratio (ICER).

RESULTS

There was no significant difference in the patients' backgrounds. The ITT analysis revealed an eradication rate of 94.6% for VPZ/AC and 86.7% for RPZ/AC. VPZ/AC cost 1155.4 Japanese yen (JPY) higher than RPZ/AC (34063.4 vs. 32908.0, JPY). CER of VPZ/AC was less than that of RPZ/AC (360.1 vs. 379.4, JPY per percent) and ICER of VPZ/AC was 147.0 JPY (1.28 Euro (EUR), 1 EUR =115 JPY) per percent.

CONCLUSIONS

VPZ/AC was more cost-effective than RPZ/AC as first-line therapy for H. pylori eradication.

Serological analysis of Helicobacter hepaticus infection in patients with biliary and pancreatic diseases

BACKGROUND AND AIMS

Infection with Helicobacter hepaticus has been associated with development of hepatocellular carcinoma and gallstones in animal models. In humans, however, the association of H. hepaticus infection with biliary and pancreatic diseases has not been elucidated. The aim of this study was to serologically examine the prevalence of H. hepaticus infection in patients with biliary and pancreatic diseases.

METHODS

Serum samples obtained from 55 patients with cholelithiasis, 18 with bile duct or gallbladder cancer and 19 with pancreatic cancer were studied. Sera were obtained from 34 control subjects who underwent endoscopy and were diagnosed as not having peptic ulcers or cancers. Seropositivity of H. hepaticus was examined by western blot analysis using a H. hepaticus-specific antigen. To validate the specificity, positive sera were also tested after absorption with H. hepaticus whole-cell sonicate. Serum samples were also tested for the presence of anti-Helicobacter pylori antibody.

RESULTS

Prevalence of antibody to H. hepaticus-specific antigen in patients with bile tract cancer was 38.8% and was significantly higher than in control subjects (13.1%, P < 0.05). Prevalence of antibody to H. hepaticus-specific antigen was 18.2% and 10.5% in patients with cholelithiasis and pancreatic cancer, respectively. Seropositivity for H. pylori was similar in all groups. Detection of the H. hepaticus-specific band was significantly decreased after the sera were absorbed with H. hepaticus whole-cell sonicate.

CONCLUSION

Infection with H. hepaticus might be associated with bile duct cancer. Results obtained from absorbed sera suggested high specificity of the western blot analysis.

Association of gastric epithelial apoptosis with the ability of Helicobacter pylori to induce a neutrophil oxidative burst

Both polymorphonuclear cell infiltration and increased epithelial apoptosis are seen in gastric mucosa in the presence of Helicobacter pylori infection. This study examined the association between bacterial ability to stimulate an oxidative burst in neutrophils and epithelial apoptosis. Biopsy specimens were obtained from 15 patients to detect apoptotic cells by the TUNEL method. H. pylori strains isolated from corresponding stomach biopsy samples were tested for the ability to stimulate an oxidative burst in human neutrophils. Neutrophils were isolated from healthy subjects without H. pylori infection and the oxidative burst was measured by flow cytometry with dichlorofluorescein diacetate. Stimulation with H. pylori increased both the percentage of activated cells and fluorescence intensity. There was a significant positive correlation between the number of epithelial apoptotic cells and fluorescence intensity. Increased neutrophil oxidative burst stimulated by H. pylori may play a role in enhanced gastric mucosal DNA damage and consequent atrophic gastritis and gastric cancer.

Pericholangitis in a rabbit colitis model induced by injection of muramyl dipeptide emulsified with a long-chain fatty acid

Rabbit colitis has been induced by injection of muramyl dipeptide emulsified with a long-chain fatty acid. The muramyl dipeptide emulsion was injected submucosally at six portions of the rectum and colon, 10 cm proximal to the anus, using a flexible endoscope. Six rabbits were injected six times every 2 weeks and subsequently killed 2 weeks after the last injection. The histological changes of the colon that occurred in all 6 rabbits were mononuclear cell and histiocyte infiltration with sporadic eosinophils, transmural infiltration, and well-maintained goblet cell populations. These changes were different in degree. In 4 of 6 rabbits histological examination of the liver showed pericholangitis and periductal fibrosis mimicking the pericholangitis frequently seen in patients with inflammatory bowel disease. Fibrosis bridging between the portal and portal veins occurred in 2 rabbits, and noncaseating granuloma was seen in 1 rabbit. These histological changes in our model have led to the suggestion that continuous stimulation with bacterial cell wall fragments may be involved in chronic intestinal inflammation and extraintestinal manifestations such as pericholangitis.

Extraintestinal manifestations of granulomatous enterocolitis induced in rabbits by long-term submucosal administration of muramyl dipeptide emulsified with Freund's incomplete adjuvant

We examined whether extraintestinal manifestations of granulomatous enterocolitis in rabbits might be produced by the long-term administration of muramyl dipeptide which represents the basic fragment of the bacterial cell wall, emulsified with Freund's incomplete adjuvant. Muramyl dipeptide emulsion was injected submucosally at six sites in the rectum and colon, 10 cm proximal to the anus, each time with a flexible endoscope. Seven rabbits were injected nine times or more every month, and all were sacrificed 1 month after the last injection. The histological changes in the colon in the seven rabbits were mononuclear cell infiltration, epithelioid granulomas, granulomatous lesion, and denuded and regenerative epithelia, although the changes differed in degree. In five of the seven rabbits, histological examination of the liver showed pericholangitis and periductal fibrosis, findings analogous to sclerosing cholangitis in patients with inflammatory bowel disease. In four of the seven rabbits, fibrosis bridging mainly between portal and portal veins, and, in places, between portal and central veins, was seen. Two of the seven rabbits developed polyarthritis. The histological changes in our model suggest that continuous stimulation with bacterial cell wall fragments may be involved in the extraintestinal manifestations of chronic intestinal inflammation such as that seen in inflammatory bowel disease.

Rabbit granulomatous enterocolitis induced by injection of muramyl dipeptide emulsified with Freund's incomplete adjuvant

We induced granulomatous enterocolitis in rabbits by injecting them with muramyl dipeptide (MDP), a subunit of the peptidoglycan polymers that endow the bacterial cell wall with structural rigidity, emulsified with Freund's incomplete adjuvant (FIA). Injections of 0.1 ml of a water-in-oil emulsion of MDP and FIA were given submucosally at six sites in the rectum and colon, 10 cm proximal to the anus, using a flexible endoscope. Four rabbits each were sacrificed 1, 2, and 4 weeks after a single injection of the emulsion. Another 4 rabbits each were injected six times at 1- and 2-week intervals, and were sacrificed 1 and 2 weeks after the last injection of the emulsion, respectively. In all 20 rabbits, injected with the MDP emulsion, histological findings of the colon consisted of cellular infiltrations of plasma cells and lymphocytes, granulomatous lesions, and granulomas, although the findings differed in degree. Cellular infiltration in hyperplastic villi and denuded epithelia of the small intestine were seen in 2 of 8 rabbits repeated that received MDP emulsion injections. The histological changes in this animal model may be useful for studying the pathogenesis of inflammatory bowel disease in humans.

Eradication of Helicobacter pylori with lansoprazole and clarithromycin in gastric ulcer patients

This study attempted to determine the efficacy of lansoprazole plus clarithromycin therapy in the eradication of Helicobacter pylori in gastric ulcer patients. The influence of H. pylori eradication on healing and relapse of ulcers was also studied. Thirty-nine patients received either lansoprazole 30 mg daily for 8 weeks (group 1) or clarithromycin 200 mg twice daily for 2 weeks and lansoprazole 30 mg daily for 8 weeks (group 2). Before treatment, H. pylori status was evaluated by a rapid urease test and histologic examination. H. pylori clearance and eradication were evaluated by a rapid urease test, polymerase chain reaction, and a [13C]urea breath test. Clearance of H. pylori was 0% in group 1 and was 33% in group 2. Eradication of H. pylori was 0% in group 1 and 21% in group 2. Although all five ulcers were healed in patients with H. pylori eradication, ulcers were not healed in the five patients without eradication. Relapse of ulcer was observed in three patients in whom eradication had failed. In this study, for H. pylori-positive gastric ulcer patients, better results were obtained when lansoprazole plus clarithromycin therapy was used, and H. pylori eradication was achieved.