Phase 1 Clinical Trial of PPMX-T003, a Novel Human Monoclonal Antibody Specific for Transferrin Receptor 1, to Evaluate Its Safety, Pharmacokinetics, and Pharmacodynamics

This study aimed to evaluate the safety, pharmacokinetics, and pharmacodynamics of PPMX-T003, a novel human monoclonal antibody for transferrin receptor 1 (TFR1), in healthy individuals. Forty participants were enrolled and randomized to PPMX-T003 dose groups (n = 6/group) and the placebo group (n = 10). The safety and pharmacokinetics profiles were assessed according to the sequential, ascending single-dose intravenous infusions of PPMX-T003 from 0.008 mg/kg to 0.25 mg/kg. Adverse events (AEs) after PPMX-T003 administration occurred in 16 of 30 participants. Any severe AE and AE incidence were not reported, but they tended to increase depending on the dose. Laboratory tests, vital signs, and standard 12-lead electrocardiogram showed no clinically relevant changes. Five participants experienced an infusion-related reaction but recovered on days 5-10. Regarding pharmacokinetics, PPMX-T003 has a nonlinear elimination pattern. PPMX-T003 in the 0.25 mg/kg group showed apparent (>50%) decreased serum levels of reticulocytes from day 3 and sustained moderate (<10%) fall of hematocrit and hemoglobin counts from day 7. In conclusion, the antibody-mediated blockade of TFR1 elicited the expected fall in blood cell levels and showed an acceptable safety profile, supporting the continuing development of PPMX-T003 as a new candidate for polycythemia vera treatment.

A marine sponge-derived lectin reveals hidden pathway for thrombopoietin receptor activation

N-glycan-mediated activation of the thrombopoietin receptor (MPL) under pathological conditions has been implicated in myeloproliferative neoplasms induced by mutant calreticulin, which forms an endogenous receptor-agonist complex that traffics to the cell surface and constitutively activates the receptor. However, the molecular basis for this mechanism is elusive because oncogenic activation occurs only in the cell-intrinsic complex and is thus cannot be replicated with external agonists. Here, we describe the structure and function of a marine sponge-derived MPL agonist, thrombocorticin (ThC), a homodimerized lectin with calcium-dependent fucose-binding properties. In-depth characterization of lectin-induced activation showed that, similar to oncogenic activation, sugar chain-mediated activation persists due to limited receptor internalization. The strong synergy between ThC and thrombopoietin suggests that ThC catalyzes the formation of receptor dimers on the cell surface. Overall, the existence of sugar-mediated MPL activation, in which the mode of activation is different from the original ligand, suggests that receptor activation is unpredictably diverse in living organisms.

Subcellular localization of dystrophin isoforms in cardiomyocytes and phenotypic analysis of dystrophin-deficient mice reveal cardiac myopathy is predominantly caused by a deficiency in full-length dystrophin

Duchenne muscular dystrophy (DMD) is an X-linked recessive progressive muscle degenerative disorder that causes dilated cardiomyopathy in the second decade of life in affected males. Dystrophin, the gene responsible for DMD, encodes full-length dystrophin and various short dystrophin isoforms. In the mouse heart, full-length dystrophin Dp427 and a short dystrophin isoform, Dp71, are expressed. In this study, we intended to clarify the functions of these dystrophin isoforms in DMD-related cardiomyopathy. We used two strains of mice: mdx mice, in which Dp427 was absent but Dp71 was present, and DMD-null mice, in which both were absent. By immunohistochemical staining and density-gradient centrifugation, we found that Dp427 was located in the cardiac sarcolemma and also at the T-tubules, whereas Dp71 was specifically located at the T-tubules. In order to determine whether T tubule-associated Dp71 was involved in DMD-related cardiac disruption, we compared the cardiac phenotypes between DMD-null mice and mdx mice. Both DMD-null mice and mdx mice exhibited severe necrosis, which was followed by fibrosis in cardiac muscle. However, we could not detect a significant difference in myocardial fibrosis between mdx mice and DMD-null mice. Based on the present results, we have shown that cardiac myopathy is caused predominantly by a deficiency of full-length dystrophin Dp427.

Reduced proliferative activity of primary POMGnT1-null myoblasts in vitro

Protein O-linked mannose beta1,2-N-acetylglucosaminyltransferase 1 (POMGnT1) is an enzyme that transfers N-acetylglucosamine to O-mannose of glycoproteins. Mutations of the POMGnT1 gene cause muscle-eye-brain (MEB) disease. To obtain a better understanding of the pathogenesis of MEB disease, we mutated the POMGnT1 gene in mice using a targeting technique. The mutant muscle showed aberrant glycosylation of alpha-DG, and alpha-DG from mutant muscle failed to bind laminin in a binding assay. POMGnT1(-/-) muscle showed minimal pathological changes with very low-serum creatine kinase levels, and had normally formed muscle basal lamina, but showed reduced muscle mass, reduced numbers of muscle fibers, and impaired muscle regeneration. Importantly, POMGnT1(-/-) satellite cells proliferated slowly, but efficiently differentiated into multinuclear myotubes in vitro. Transfer of a retrovirus vector-mediated POMGnT1 gene into POMGnT1(-/-) myoblasts completely restored the glycosylation of alpha-DG, but proliferation of the cells was not improved. Our results suggest that proper glycosylation of alpha-DG is important for maintenance of the proliferative activity of satellite cells in vivo.

Autologous transplantation of SM/C-2.6(+) satellite cells transduced with micro-dystrophin CS1 cDNA by lentiviral vector into mdx mice

Duchenne muscular dystrophy (DMD) is a lethal muscle disorder caused by mutations in the dystrophin gene. Transplantation of autologous myogenic cells genetically corrected ex vivo is a possible treatment for this disorder. In order to test the regenerative efficiency of freshly isolated satellite cells, we purified quiescent satellite cells from limb muscles of 8-12-week-old green fluorescent protein-transgenic (GFP-Tg) mice using SM/C-2.6 (a recently developed monoclonal antibody) and flow cytometry. Freshly isolated satellite cells were shown to participate in muscle regeneration more efficiently than satellite cell-derived myoblasts passaged in vitro do, when transplanted into tibialis anterior (TA) muscles of 8-12-week-old cardiotoxin-injected C57BL/6 mice and 5-week-old dystrophin-deficient mdx mice, and analyzed at 4 weeks after injection. Importantly, expansion of freshly isolated satellite cells in vitro without passaging had no detrimental effects on their regenerative capacity. Therefore we directly isolated satellite cells from 5-week-old mdx mice using SM/C-2.6 antibody and cultured them with lentiviral vectors expressing micro-dystrophin CS1. The transduced cells were injected into TA muscles of 5-week-old mdx mice. At 4 weeks after transplantation, the grafted cells efficiently contributed to regeneration of mdx dystrophic muscles and expressed micro-dystrophin at the sarcolemma. These results suggest that there is potential for lentiviral vector-mediated ex vivo gene therapy for DMD.

Risk assessment of human myelotoxicity of anticancer drugs: a predictive model and the in vitro colony forming unit granulocyte/macrophage (CFU-GM) assay

Myelotoxicity is one of the major limitations to the use of anticancer drugs. It is desirable to evaluate human myelotoxicity before a Phase I study, however, this is difficult because of the differences in susceptibility between humans and animals. The purpose of this study was to establish a reliable method to predict the human maximum tolerated dose (MTD) of five camptothecin derivatives: SN-38, DX-8951f, topotecan (TPT), 9-aminocamptothecin (9-AC), and camptothecin (CAM). The myelotoxicity of camptothecin derivatives was evaluated on bone marrow from mice, dogs, and humans using a 14-day colony-forming unit-granulocyte/macrophage (CFU-GM) assay to determine the 50%, 75%, and 90% inhibitory concentration values (IC50, IC75, and IC90, respectively). Then, using human and murine IC90 values for myelotoxicity of these compounds, in vivo toxicological data, and pharmacokinetic parameters (data referred to the literature), human MTDs were predicted retrospectively. The mechanism-based prediction model which is proposed uses the in vitro CFU-GM assay and in vivo parameters on the basis of free fraction of area under the concentration-curve (AUC) at the MTD (r2 = 0.887) and suggests that the human MTDs were well predicted for the five camptothecin derivatives by this model rather than by other models. The application of this model for in vitro hematotoxicology could be very useful in the development of new anticancer agents.

Pharmacokinetics of DE-310, a novel macromolecular carrier system for the camptothecin analog DX-8951f, in tumor-bearing mice

To improve the distribution of the novel camptothecin analog DX-8951, DE-310, which is composed of DX-8951 covalently linked to a macromolecular carrier by a peptidyl (GGFG) spacer, was designed to exploit the Enhanced Permeability and Retention (EPR) effect. To compare the pharmacokinetics of a single dose of DE-310 with that of DX-8951f in Meth A tumor-bearing mice, the concentrations of conjugated DX-8951 (carrier-bound DX-8951), released DX-8951, and glycyl DX-8951 (G-DX-8951) were determined in plasma, liver, and tumor tissue. The concentrations of conjugated DX-8951 in tumor tissue were lower than those in plasma, with an AUC(0-inf) of 1/6 that of plasma; however, the AUC(0-inf) of released DX-8951 in tumor tissue was 30 times greater than that in plasma. The half-life (t1/2) of conjugated DX-8951, released DX-8951, and G-DX-8951 in plasma, liver, and tumor tissue were 2-3 days. In contrast, after administration of 14C-DX-8951f, the radioactivity in tumor tissue decreased in parallel with the decrease in plasma concentrations, with a t1/2(0.083-3 h) of 0.6 h. These data show that higher levels and longer retention of conjugated DX-8951 and released DX-8951 occur in tumor tissue after the administration of DE-310 to Meth A tumor-bearing mice. These results indicate that DE-310 improves the pharmacokinetic profileof DX-8951f, particularly, its ability to target tumor tissue.

Evaluation of a PCR primer based on the isocitrate dehydrogenase gene for detection of Helicobacter pylori in feces

In order to improve detection and identification of Helicobacter pylori in highly contaminated samples, we evaluated new specific primers based on the DNA base sequence within the isocitrate dehydrogenase (icd) gene to amplify a 1,200-bp DNA segment. The specificity of the icd primer was tested against DNA derived from various bacteria, including 7 Helicobacter species and a panel of 1 gram-variable, 2 gram-positive, and 16 gram-negative bacteria, as well as DNA from houseflies and feces from H. pylori-negative patients. The primers permitted the detection of all clinical H. pylori isolates tested, but no reactions were observed with negative controls. Several procedures for DNA extraction from feces were evaluated using PCR with icd primers. The lower limits of detection of H. pylori DNA from two different sources containing the same number of H. pylori organisms, a pure culture and feces spiked with H. pylori, were established for each extraction method tested. The results were 8.0 x 10(3) CFU/ml for cultures of pure H. pylori, and 8.0 x 10(6) CFU/ml for H. pylori from feces, using the phenol-chloroform method; 8.0 x 10(2) and 7.0 x 10(3) CFU/ml, respectively, for a glass matrix and chaotropic solution protocol; 8.0 x 10(2) and 7.0 x 10(3) CFU/ml, respectively, for the QIAamp tissue kit; and 5.0 x 10(2) and 5.0 x 10(3) CFU/ml, respectively, for the XTRAX DNA extraction kit. We conclude that the use of the icd gene as a primer for PCR represents a specific and sensitive assay for detection of H. pylori in highly contaminated samples.

Stereoselective chiral inversion of pantoprazole enantiomers after separate doses to rats

(+/-)-Pantoprazole ((+/-)-PAN), (+/-)-5-(difluoromethoxy)-2-[[3.4-dimethoxy-2-pyridinyl)methyl]sul finyl]- 1H-benzimidazole) is a chiral sulfoxide that is used clinically as a racemic mixture. The disposition kinetics of (+)-PAN and (-)-PAN given separately has been studied in rats. Serum levels of (+)- and (-)-PAN and its metabolites, pantoprazole sulfone (PAN-SO2), pantoprazole sulfide (PAN-S), 4'-O-demethyl pantoprazole sulfone (DMPAN-SO2), and 4'-O-demethyl pantoprazole sulfide (DMPAN-S) were measured by HPLC. Following single intravenous or oral administration, both enantiomers were rapidly absorbed and metabolized, resulting in similar serum concentrations, suggesting that the two enantiomers have approximately the same disposition kinetics. The major metabolite of both (+)- and (-)-PAN was PAN-SO2, while DMPAN-SO2 was also detected as a minor metabolite. Serum levels of PAN-S and DMPAN-S could not be quantified after intravenous or oral administration of either enantiomer. Significant chiral inversion occurred after intravenous and oral administration of (+)-PAN. The AUCs of (-)-PAN after intravenous and oral dosing of (+)-PAN were 36.3 and 28.1%, respectively of those of total [(+) + (-)] PAN. In contrast, the serum levels of (+)-PAN were below quantitation limits after intravenous or oral administration of (-)-PAN. Therefore, chiral inversion was observed only after administration of (+)-PAN, supporting the hypothesis that stereoselective inversion from (+)-PAN to (-)-PAN occurs in rats.

An evaluation of the cytochrome P450 induction potential of pantoprazole in primary human hepatocytes

Primary human hepatocytes contain a full complement of human drug-metabolizing enzymes and therefore represent a relevant experimental system for the evaluation of pharmacokinetic drug-drug interaction potential in human. In this study, the cytochrome P450 (CYP) induction potential of pantoprazole (PAN) was evaluated and compared to two other proton pump inhibitors (PPIs), omeprazole (OM) and lansoprazole (LAN). Primary human hepatocytes from three donors were studied. The hepatocytes were cultured for 3 days, followed by treatment for 3 days with the PPIs at 2, 5 and 10 microM. Two other known CYP inducers, 3-methylcholanthrene at 1 microM and rifampin at 50 microM, were also evaluated. Induction potentials of these chemicals for CYP1A and CYP3A were evaluated by isozyme activity and isozyme content. 7-Ethoxyresorufin-O-deethylase and testosterone 6beta-hydroxylase activities were used as endpoints for CYP1A and CYP3A, respectively. Isozyme protein contents of CYP1A and CYP3A were evaluated via Western blotting. The results showed that for CYP1A induction, the rank ordering in induction potential was consistently OM > LAN > PAN. CYP3A induction by the PPI's were observed in two of the three hepatocyte cultures, with no apparent differences in induction potency for the three compounds. Our results on CYP1A induction suggest that PAN has a lower drug-drug interaction potential than OM and LAN.

Effects of proton pump inhibitors on thyroid hormone metabolism in rats: a comparison of UDP-glucuronyltransferase induction

The effects of proton pump inhibitors on thyroid hormone metabolism in rats were examined. Pantoprazole, omeprazole, and lansoprazole were administered repeatedly to female SD rats at doses of 5, 50, and 300 mg/kg/day for 1 week, and changes in UDP-glucuronyltransferase activities were examined. Increases in o-aminophenol UDP-glucuronyltransferase activity, which was measured as that responsible for the glucuronidation of thyroxine, were evident following 7-day high-dose administration of all the proton pump inhibitors tested. Of the three proton pump inhibitors investigated, o-aminophenol UDP-glucuronyltransferase activity was greatest following the high-dose administration of omeprazole. Androsterone UDP-glucuronyltransferase activity in rats treated with the proton pump inhibitors increased significantly, but these increases were smaller than those of o-aminophenol UDP-glucuronyltransferase. Pantoprazole and omeprazole treatment did not affect plasma T4 or T3 significantly, whereas lansoprazole treatment produced marked reductions in plasma T4 but did not affect plasma T3 significantly. After administration of 125I-labeled thyroid hormone to rats treated with the proton pump inhibitors, biliary excretion of radioactivity increased significantly in omeprazole- and lansoprazole-treated rats; these increases were attributed to induction of liver thyroxine UDP-glucuronyltransferase activities. The order of biliary excretion of radioactivity, as well as the o-aminophenol UDP-glucuronyltransferase activity, in the treated animals was: omeprazole > lansoprazole > pantoprazole. Therefore, repeated administration of the proton pump inhibitors increased thyroxine-metabolizing activity via induction of UDP-glucuronyltransferase, and this induction by pantoprazole was less pronounced than that by omeprazole or lansoprazole.

An evaluation of the CYP1A induction potential of pantoprazole in primary rat hepatocytes: a comparison with other proton pump inhibitors

The ability of pantoprazole to affect the induction of cytochrome P450 (CYP) 1A subfamily was evaluated and compared with two other proton pump inhibitors, omeprazole and lansoprazole, in primary cultured hepatocytes from female Sprague-Dawley rats. The hepatocytes were cultured for 2 days, followed by treatment for 2 days with the proton pump inhibitors at 2, 5 and 10 microM, concentrations that are similar to plasma concentrations found in rats in vivo. The CYP1A inducer 3-methylcholanthrene (at 1 microM) was also evaluated as a positive control. Induction potentials of these chemicals for CYP1A were determined by 7-ethoxyresorufin O-deethylase activity and isozyme contents. The results showed that for CYP1A induction, the rank ordering in induction potential was consistently lansoprazole > omeprazole > pantoprazole. The results are consistent with the existing rat in vivo data, i.e. pantoprazole has lower CYP1A induction potential than omeprazole and lansoprazole.

Effects of pantoprazole on xenobiotic metabolizing enzymes in rat liver microsomes: a comparison with other proton pump inhibitors

The effects of pantoprazole on xenobiotic metabolizing enzymes in rat liver microsomes were examined. Groups of female Sprague-Dawley rats were orally administered pantoprazole and other proton pump inhibitors, omeprazole and lansoprazole, at 5, 50, or 300 mg/kg/day for 7 days, followed by assays to detect changes in the levels of liver microsomal protein, cytochrome P450, cytochrome b5, NADPH cytochrome c reductase, and drug metabolizing enzyme activities. Increases in total cytochrome P450 contents were evident after a 7-day high-dose administration of all the proton pump inhibitors tested, and the increase by treatment with pantoprazole was less than that with lansoprazole. The three proton pump inhibitors increased the enzymatic activities and cytochrome P450 enzyme levels of CYP1A, CYP2B, and CYP3A. CYP1A was less induced with pantoprazole than with omeprazole or lansoprazole. In contrast, CYP2B was more strongly induced with pantoprazole than with other proton pump inhibitors. NADPH cytochrome c reductase was induced with omeprazole and pantoprazole. The present results suggest that enzyme induction differs among these proton pump inhibitors not only quantitatively but also qualitatively.

Placental transfer and milk secretion of gadodiamide injection in rats

The disposition of gadodiamide (CAS 122795-43-1) injection (Omniscan), a nonionic paramagnetic contrast-enhancing medium developed for magnetic resonance imaging, was characterized in the pregnant and lactating rat. After a single intravenous dose of 0.3 mmol/kg 14C-labeled gadodiamide to rats on day 18 of gestation, the maximum levels of radioactivity in the fetus were attained at 5 min, and were approximately 170 times lower than those in the maternal plasma. The AUC ratio of fetal to maternal blood was less than 0.1. Moreover, the distribution percentage of radioactivity in the fetus were on the average 0.01% of the administered dose up to 4 h, and trace amounts of radioactivity were present in fetal tissues at 24 h after dosing. Whole body autoradiography showed that the smallest amounts of radioactivity were present in the fetus, whereas the highest concentrations of radioactivity were noted in the fetal membrane and the kidney at 24 h after dosing. These results indicate that exposure of the developing rat fetus to gadodiamide after maternal drug administration is quantitatively small. The radioactivity levels in the milk increased with time, reaching a maximum 1 h after dosing, and gradually decreased to levels below detection limits over 8 h. A comparison of the AUCs of milk and plasma showed the comparatively small amounts of the drug excreted into milk.

[An enzyme-linked immunosorbent assay for the detection of IgG antibodies against urease of Helicobacter pylori]

We have developed an enzyme-linked immunosorbent assay (ELISA) for the detection of IgG antibodies against Helicobacter pylori (HP) using purified HP urease as an antigen. The urease was purified from ultrasonicated extract of HP by NaCl linear gradient system on DEAE-Sepharose 4B chromatography. Two molecular weight bands, 65kD and 27kD were observed on a SDS-PAGE gel in the purified urease sample. The urease antigen did not crossreact to rabbit antibodies prepared against Campylobacter coli and Campylobacter jejuni. Out of 93 gastric biopsy patients, sixty nine patients (74.2%) were positive in HP culture test. Serum HP antibody titers (AU: arbitrary unit) of HP culture positive and negative patients were 42.9 +/- 47.4 and 16.7 +/- 25.7 (mean +/- SD), respectively (p < 0.05). The ELISA system have sensitivity of 72.5% and specificity of 70.8%. We believe that the ELISA system is useful for diagnosis and monitoring of HP infection.

[Helicobacter pylori and the development of atrophic gastritis]

A close relationship between H. pylori infection and atrophic gastritis has been reported, and atrophic gastritis has been thought of as one of the precursors of gastric carcinoma. It was reported that there was a significant positive correlation between the reduction of serum pepsinogen (PG) I/II ratio and the progression of atrophic gastritis. The ratio of PG I/II was significantly decreased in H. pylori positive patients when compared to H. pylori negative patients with chronic gastritis. The PG I/II ratio in gastric cancer was significantly lower than that of chronic gastritis, while the prevalence of H. pylori was not significant difference between gastric carcinoma and chronic gastritis. It is suggested that there is strong correlation between H. pylori infection and the development of atrophic gastritis, and that eradication of H. pylori from gastric mucosa might reduce the risk of developing gastric carcinoma.

[Helicobacter pylori and urease activity--comparative study between urease positive and negative mutant strains]

The ammonia concentration in the gastric juice from H. pylori positive cases was significantly higher than that from negative cases, and there was positive correlation between number of H. pylori, gastritis score and ammonia concentration in gastric juice. It is suggested that ammonia in gastric juice which is produced by powerful urease activity of H. pylori is one of the pathogenic factors in gastritis. We succeeded in producing a urease-negative mutant strain of H. pylori. This strain did not colonize gastric mucosa of Cynomolgus monkeys. H. pylori survival time in vitro was increased at pH 2.0 in the presence of urea. These results suggest that urease facilitates colonization of gastric mucosa by H. pylori, and prolongs the survival of H. pylori in an acidic environment.

[Isolation identification and quantitative culture of Helicobacter pylori from gastric mucosa]

The biopsy specimens were homogenized and diluted ten-fold serially in Hank's solution. Each dilution samples were streaked on Skirrow's selective medium. The plates were incubated at 37 degrees C 5 to 7 days under micro-aerobic condition and counting the viable cell of H. pylori. The positive rate of specimens with H. pylori in active gastric ulcer tissue (62.0%) was higher than that in scarred tissue (51.9%). Number of H. pylori viable cells in active ulcer tissue was significantly larger than in scarred tissue. The positive correlation between Raw's gastritis score of specimens from patients with erosive gastritis and number of H. pylori viable cells was clearly noticed.

[Experimental infection of the cynomolgus monkey with Helicobacter pylori]

To better understand the pathogenesis of Helicobacter pylori (H. pylori) associated gastritis and to evaluate the effectiveness of potential therapies in ulcer healing, we established an experimental animal model of H. pylori infection. A strain of H. pylori was isolated from the stomach of a Cynomolgus monkey, cultured and used to inoculate as a group of H. pylori negative monkeys. H. pylori-induced changes in the gastric mucosa was monitored both endoscopically and by histological evaluation of mucosal biopsy. After inoculation, H. pylori was found to colonize the gastric mucosa of these primates and had induced gastritis. In a related experimental series, we developed an experimental acetic-acid induced ulcer in the stomach of these monkeys. These results suggest that the Cynomolgus monkey may be a useful model to study H. pylori infection.

Is Helicobacter pylori a causal agent in gastric carcinoma?

The aim of this study is to clarify the relationship between Helicobacter pylori (H. pylori) infection and gastric carcinoma. 94 patients with gastric carcinoma and 111 patients with chronic gastritis were involved in this study. They were classified into 3 age groups: Group A (40 years and under), Group B (41-59), Group C (60 years and over). Serum samples were tested for H. pylori IgG antibodies by ELISA and for pepsinogen (PG) by RIA. The ratio of PG I/PG II was used as a marker for atrophic gastritis. Results were as follows. In the incidence of H. pylori antibodies, there was no significant differences between gastric carcinoma and chronic gastritis in any of the groups. In the quantity of H. pylori antibodies, there was no significant difference between gastric carcinoma and chronic gastritis in any of the groups. The ratio of PG I/PG II was significantly decreased in H. pylori positive cases when compared to H. pylori negative cases in each group with chronic gastritis and group A and B with gastric carcinoma. The ratio of PG I/PG II in gastric carcinoma was significantly lower than that of chronic gastritis. As conclusion, from the point of view of the prevalence of H. pylori, it is suggested that H. pylori is not a direct causal agent in the pathogenesis of gastric carcinoma.

Serial change of gastric mucosa after challenging with Helicobacter pylori in the cynomolgus monkey

The aim of this study was to clarify the change of the gastric mucosa following inoculation with Helicobacter pylori (H. pylori). Two pairs of cynomolgus monkeys received either H. pylori of human origin (group A) or H. pylori of monkey origin (group B) by intragastric inoculation at a dose of 10(9) CFU. After inoculation, endoscopical observation and biopsies were done every 7 days for one month. The bacteria in the biopsy samples were cultured quantitatively. The content of intracellular PAS-AB positive substance was quantitatively analyzed with the image analyzing system. Results were as follows: 1) Before inoculation, the gastric mucosa was endoscopically normal and free from H. pylori. 2) The quantity of H. pylori varied from 0 to 10(3) CFU/0.1 g tissue in group A and from 10 to 10(6) CFU/0.1 g tissue in group B. 3) Severe erosion was seen in group B, while mild mucosal erythema and erosion were observed in group A. 4) There was a correlation between the quantity of H. pylori and histological activity (Rauws' gastritis score). 5) The PAS-AB positive substance in H. pylori-positive mucosa was less than that in H. pylori-negative mucosa. In conclusion, gastric mucosal changes of varying degrees were brought about after inoculation of H. pylori depending on the quantity of bacilli in the gastric tissue.