Jochen Rudi

Involvement of the CD95 (APO-1/Fas) Receptor and Ligand System in Helicobacter pylori -induced Gastric Epithelial Apoptosis

Helicobacter pylori infection is associated with chronic gastritis, peptic ulceration, and gastric carcinoma. The potential role of CD95-mediated apoptosis was investigated in a panel of gastric biopsies obtained from patients with H. pylori-associated chronic gastritis (n = 29) and with noninfected normal mucosa (n = 10). Immunohistochemistry revealed increased CD95 receptor expression in epithelial and lamina propria cells in chronic gastritis. By in situ hybridization, CD95 ligand mRNA was absent or low in normal mucosa but expressed at high levels in lamina propria lymphocytes and, unexpectedly, in epithelial cells in chronic gastritis. Apoptotic cells were rare in normal mucosa but were observed regularly in chronic gastritis in close proximity to CD95 ligand mRNA expression throughout the epithelial and lamina propria cells. In a functional analysis gastric epithelial cell lines were incubated with supernatants of H. pylori. Treatment with the cytotoxic isolate H. pylori 60190 but not with the noncytotoxic isolate Tx30a upregulated CD95 in up to 50% of gastric epithelial cells and induced apoptosis in these cells. H. pylori-induced apoptosis was partially prevented by blocking CD95, demonstrating the functional role of the CD95 system. These findings suggest that H. pylori-associated chronic gastritis involves apoptosis of gastric epithelial cells by activation of the CD95 receptor and ligand system.

Vacuolating Cytotoxin of Helicobacter pylori Induces Apoptosis in the Human Gastric Epithelial Cell Line AGS

ABSTRACT Helicobacter pylori induces cell death by apoptosis. However, the apoptosis-inducing factor is still unknown. The virulence factor vacuolating cytotoxin A (VacA) is a potential candidate, and thus its role in apoptosis induction was investigated in the human gastric epithelial cell line AGS. The supernatant from thevacA wild-type strain P12 was able to induce apoptotic cell death, whereas the supernatant from its isogenic mutant strain P14 could not. That VacA was indeed the apoptosis-inducing factor was demonstrated further by substantial reduction of apoptosis upon treatment of AGS cells with a supernatant specifically depleted of native VacA. Furthermore, a recombinant VacA produced inEscherichia coli was also able to induce apoptosis in AGS cells but failed to induce cellular vacuolation. These findings demonstrate that the vacuolating cytototoxin of H. pyloriis a bacterial factor capable of inducing apoptosis in gastric epithelial cells.

Hepatocyte proliferation in primary biliary cirrhosis as assessed by proliferating cell nuclear antigen and Ki-67 antigen labelling

Expression of the proliferating cell nuclear antigen and Ki-67 antigen by hepatocytes was investigated in liver tissue specimens of 29 patients with primary biliary cirrhosis (stage I 13, stage II 6, stage III 5 and stage IV 5 patients) prior to treatment with ursodeoxycholic acid and of five control subjects using immunocytochemical methods. Proliferating cell nuclear antigen and Ki-67 expression were reevaluated in seven patients after 3 years of treatment with ursodeoxycholic acid. Proliferating cell nuclear antigen labelling indices were significantly higher in primary biliary cirrhosis (stage I, 6.4% to 32.4%, median, 10.9%; stage II, 9.6% to 21.6%, median 11.4%; stage III, 5.2% to 12.5%, median, 7.6%; stage IV, 3.8% to 8.9%, median, 5.6%) than in controls (0% to 0.5%, median, 0.1%; p < 0.005). Ki-67 antigen labelling counts were lower than proliferating cell nuclear antigen indices but elevated in all stages of primary biliary cirrhosis (stage I, 0.5% to 3.5%, median 2.0%; stage II, 1.8% to 3.6%, median 2.6%; stage III, 1.3% to 2.5%, median 1.9%; stage IV, 0.4% to 1.7%, median 1.0%) compared with controls (0% to 0.5%, median 0.3%; p < 0.005). After ursodeoxycholic acid treatment, mean proliferating cell nuclear antigen and Ki-67 labelling indices decreased from a median of 9.0% (range, 3.8% to 32.4%) to a median of 7.8% (range, 4.5% to 17.2%; p = 0.045) for proliferating cell nuclear antigen and from a median of 2.5% (range, 0.8% to 3.6%) to a median of 2.1% (range, 0.9% to 3.1%; p = 0.031) for Ki-67 antigen. It is concluded that hepatocyte proliferation is markedly increased in primary biliary cirrhosis, particularly in the early stages of the disease, and that ursodeoxycholic acid treatment reduces proliferative activity in primary biliary cirrhosis.

Serum Antibodies Against Helicobacter pylori Proteins VacA and CagA Are Associated with Increased Risk for Gastric Adenocarcinoma

Infection with Helicobacter pylori is associatedwith the development of gastric cancer. To study whetherthe infection with H. pylori strains expressing thevacuolating cytotoxin (VacA) and/or thecytotoxin-associated protein (CagA) is associated with an increasedrisk of developing gastric adenocarcinoma, sera of 90patients with gastric cancer and 90 matched controlswith cardiovascular diseases were investigated for the presence of antibodies to VacA and CagA byimmunoblot. Although no significant difference in theoverall H. pylori seropositivity was found betweencancer patients and controls, antibodies against VacA or CagA were significantly more frequent incancer patients than in control subjects. Seventyfive(97.4%) of 77 H. pylori-positive patients in the cancergroup, but only 60 (84.5%) of 71 H. pylori-positive control patients had antibodies against eitherVacA or CagA (χ2 6.63; relative risk,2.00; 95% confidence interval, 1.18–3.39; P =0.01). The presence of antibodies against VacA or CagAalone was also associated with an increased cancer risk (92.2%vs 80.3%; χ2 = 5.30; relative risk, 1.74;95% confidence interval, 1.08–2.78; P = 0.021, forVacA; and 87.0% vs 74.6%; χ2 4.90;relative risk, 1.61; 95% confidence interval, 1.06–2.45; P =0.037, for CagA). The relative risk for gastric cancerwas mainly elevated in patients under 65 years, but notin patients at or over 65 years. There is evidence that infection with VacA- or CagA-producing H.pylori strains increases the risk of developing gastriccancer, especially in younger patients.

Helicobacter pylori infection as an independent risk factor for cerebral ischemia of atherothrombotic origin

Chronic infection may increase the risk for ischemic stroke. Presently, it is insufficiently established whether Helicobacter pylori infection represents a risk factor for ischemic stroke. We analyzed IgG antibodies against H. pylori in 109 patients with acute cerebral ischemia and 82 age- and sex-matched control patients with non-vascular and non-inflammatory neurological diseases. Antibody titers were significantly higher in patients than in control subjects (p=0.007). H. pylori seropositivity tended to be more common in patients (odds ratio (OR) 1.55, 95% confidence interval (ci) 0.87-2.76), but this trend was further attenuated in multivariate analysis (OR 1.42; 95% 0.75-2.67) with hypertension, diabetes mellitus, current or previous smoking, previous cerebral ischemia and low socioeconomic status. H. pylori seropositivity increased the odds for cerebral ischemia of atherothrombotic origin in univariate (OR 3.63; 95% ci 1.37-9.65) and multivariate analysis (OR 3.53; 95% ci 1.09-11.4). H. pylori seropositivity may be an independent risk factor for stroke of atherothrombotic origin.

Association Between Cerebral Ischemia and Cytotoxin-Associated Gene-A–Bearing Strains of Helicobacter pylori

Background and Purpose— Studies on Helicobacter pylori infection and risk of ischemic stroke yielded variable results. Infection with more virulent H. pylori strains, such as cytotoxin-associated gene-A (CagA)–bearing strains, may be of particular relevance for ischemic diseases. We investigated whether H. pylori and CagA seropositivity are independent risk factors for cerebral ischemia or its etiologic subtypes. Methods— We determined IgG antibodies against H. pylori and CagA protein (enzyme immunoassays) in 190 patients with acute cerebral ischemia and in 229 age- and sex-matched control subjects selected randomly from the general population. Results— CagA seropositivity was more common in patients (114/190; 60.0%) than in control subjects (99/229; 43.2%; odds ratio, 1.97; 95% CI, 1.33 to 2.91; P <0.001). This result remained significant after adjustment for age, sex, vascular risk factors and diseases, and childhood and adult social status (odds ratio, 1.84; 95% CI, 1.13 to 3.00; P =0.015). Subgroup analyses yielded similar results in all etiologic stroke subtypes. In contrast, H. pylori seropositivity in general was not associated with increased risk of stroke or its etiologic subtypes. Conclusions— Our results support the hypothesis of an association between infection with CagA-positive H. pylori strains and acute cerebral ischemia.

Systemic Chemotherapy with Epirubicin for Treatment of Advanced or Multifocal Hepatocellular Carcinoma

Background: The purpose of this retrospective study was to determine the response rate and effect on survival of chemotherapy with epirubicin in non-resectable advanced hepatocellular carcinoma (HCC). Methods: Fifty-two patients with non-resectable disease were treated with epirubicin. A treatment cycle consisted of 20 mg/m2 i.v. on days 1, 8 and 15 and was repeated every 4 weeks to a maximum dose of 1,000 mg/m2. Forty-four patients were eligible for analysis. Results: Out of 44 patients, 1 (2.3%) achieved a complete response, 3 (6.8%) had partial responses and 16 (36%) had stable disease (SD). For patients with successful disease control (complete and partial responders and patients with SD), the median survival was 16.2 months; for non-responders, it was 6.1 months (p < 0.003). Eight (88.9%) of 9 patients with alpha-fetoprotein (AFP) levels <50 µg/l achieved successful disease control compared to 12 (34.9%) out of 35 patients with initially elevated AFP (p < 0.0001). Conclusion: Epirubicin appears to be an active therapeutic option for patients with non-resectable HCC. Especially the subgroup of patients with low levels of AFP may benefit from this treatment.

Lack of Association of Helicobacter pylori Seroprevalence and Gastric Cancer in a Population with Low Gastric Cancer Incidence

BACKGROUND Previous studies have suggested that infection with Helicobacter pylori is associated with an increased risk of gastric adenocarcinoma. METHODS We examined the sera of 111 Caucasian patients with histologically confirmed gastric cancer (36 with cancer of the cardia, 70 with cancer of the body or antrum, and 5 with stump carcinomas after Billroth-II procedures) and 111 age-matched controls with colorectal carcinomas for the presence of H. pylori IgG antibodies by enzyme-linked immunoassay. RESULTS The overall prevalence of H. pylori infection was 58.6% (65 of 111) in gastric cancer patients as compared with 50.5% (56 of 111) in matched control subjects (odds ratio, 1.39; 95% confidence interval, 0.82 to 2.36). Carcinomas of the cardia were not linked to H. pylori infection (odds ratio, 1.25; 95% confidence interval, 0.65 to 2.46), nor diffuse or intestinal-type carcinomas (odds ratios, 1.79 and 1.0; 95% confidence intervals, 0.69 to 4.67 and 0.34 to 2.91, respectively). Age, sex, and height of the IgG immune response did not affect risk. CONCLUSIONS In contrast to previous results, these data do not provide evidence that the contribution of H. pylori infection to the carcinogenesis of gastric cancer is of major significance in a population with low gastric cancer rates and with high socioeconomic status.

Role of apoptosis in gastric epithelial turnover.

Gastric epithelial turnover is a dynamic process. It is characterized by continous cell proliferation, which is counterbalanced by cell loss. The biological principle that mediates the homeostasis of epithelium is programmed cell death, or apoptosis. Currently, several subtypes of apoptosis are distinguished, which are mediated by different mechanisms. Various subtypes of apoptosis also occur in the gastric epithelium under various conditions. In the normal stomach, apoptosis due to cell isolation (anoikis) mediates the physiological epithelial turnover. Albeit rarely seen in routine histology, approximately 2% of epithelial cells in the normal stomach are apoptotic. In Helicobacter pylori‐induced gastritis, apoptosis and epithelial proliferation are moderately increased, with approximately 8% apoptotic epithelial cells. In gastritis, factors such as CD95 ligand or tumor necrosis factor (TNF) alpha act as death factors. They bind to specific receptors, CD95 and TNF‐R, which are induced either by other cytokines, such as interferon gamma, or by Helicobacter pylori itself. In addition to CD95, H.pylorican also induce upregulation of CD95 ligand expression. Taken together, the upregulated expression of CD95, and the presence of CD95L in the close proximity to apoptotic gastric epithelial cells suggest a functional role of the CD95‐CD95L system in the induction of apoptosis in H.pylori‐gastritis. The role of other pathways to apoptosis is currently under study. Apart from being a biological phenomenon, apoptosis in the stomach may also have direct clinical consequences. An extreme example is given in gastric graft‐vs.‐host disease when epithelial denudement occurs. Microsc. Res. Tech. 48:303–311, 2000

Simultaneous gastric adenocarcinoma and MALT-type lymphoma in Helicobacter pylori infection

A 79-year-old women with upper abdominal pain, vomiting and weight loss was found at endoscopy to have a large tumour mass in the gastric body. Histology of forceps biopsies revealed an adenocarcinoma of intestinal type. Gastrectomy was performed, but extensive lymph node metastasis precluded a curative surgical approach. Histopathological study of the specimen, however, revealed two distict malignancies, which arose in the setting of Helicobacter pylori-associated chronic gastritis with partial mucosal atrophy. One tumour was a gastric carcinoma, while the other was a primary B-cell lymphoma of the stomach (CD20-positive). The lymphoma comprised both a low-grade component (mucosa-associated lymphoid tissue- or MALT-type lymphoma), and a high-grade component (large cell lymphoma with CD30-positive giant cells). Infection with H. pylori was confirmed by the serological presence of IgG antibodies to H. pylori-antigens, including antibodies against the 128 kDa protein of the cytotoxin-associated gene (cagA gene) of H. pylori.