RESUMO
AIM: To evaluate the prevalence of Helicobacter pylori (H. pylori) babA2, babB and a recombinant gene between babA2 and babB (babA2/B), and their role in the development of atrophic gastritis in Costa Rican and Japanese clinical isolates. METHODS: A total of 95 continuous H. pylori-positive Costa Rican (41 males and 54 females; mean age, 50.65 years; SD, +/- 13.04 years) and 95 continuous H. pylori-positive Japanese (50 males and 45 females; mean age, 63.43; SD, +/- 13.21 years) patients underwent upper endoscopy from October 2005 to July 2006. They were enrolled for the polymerase chain reaction (PCR)-based genotyping of the H. pylori babA2, babB and babA2/B genes. Statistical analysis was performed using the chi(2) test and the Fisher's exact probability test and multivariate analysis was performed by logistic regression adjusting for gender and age. P < 0.05 was regarded as statistically significant. RESULTS: The PCR-based genotyping of 95 Costa Rican and 95 Japanese isolates showed a higher prevalence of babA2 in Japan (96.8%) than in Costa Rica (73.7%), while that of babA2/B was higher in Costa Rica (11.6%) than in Japan (1.1%). In Costa Rican isolates only, babA2 was significantly associated with atrophic gastritis (P = 0.01). CONCLUSION: These results suggest that the status of babA2 and babA2/B shows geographic differences, and that babA2 has clinical relevance in Costa Rica.
Assuntos
Adesinas Bacterianas/genética , Gastrite Atrófica/microbiologia , Infecções por Helicobacter/epidemiologia , Helicobacter pylori/genética , Adulto , Fatores Etários , Idoso , Costa Rica/epidemiologia , Feminino , Gastrite Atrófica/epidemiologia , Humanos , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Prevalência , Recombinação Genética , Fatores SexuaisRESUMO
The detection of gastric premalignant lesions, atrophic gastritis, corpus atrophic gastritis, and intestinal metaplasia, using several potential markers was examined in Costa Rica. Depending on the lesion investigated, from a total of 223 dyspeptic patients, 58 (26.0%), 31 (13.9%), or 23 (10.3%) were histologically diagnosed with atrophic gastritis, corpus atrophic gastritis, or intestinal metaplasia, respectively. Sera were used for the measurement of pepsinogen (PG) and Helicobacter pylori CagA antibody (CagA-ab) levels by ELISA, and human genomic DNAs were used for the genotyping of interleukin (IL)-1beta (-511 and +3954), IL-10 (-1082 and -592), and IL-1RN intron 2 by PCR and RFLP. Multivariate analysis was done adjusting for sex, age, and H. pylori seropositivity. Low PG levels (L-PG; PG I < or = 70 microg/L + PG I/II < or = 3), very low PG levels (VL-PG; PG I < or = 30 microg/L + PG I/II < or = 2), and CagA-ab were individually associated with all premalignant lesions whereas IL-1beta +3954T-carrier and IL-1RN homozygous 2 allele were associated with intestinal metaplasia. VL-PG, for corpus atrophic gastritis detection, was the single marker with the highest combination of test characteristics, sensitivity (77.4%), specificity (80.7%), positive predictive value (39.3%), negative predictive value (95.7%), and seropositivity rate (27.4%), expected to improve after periodic measurements. Combined examinations of VL-PG and CagA-ab improved the specificity (92.7%) and positive predictive value (62.2%), with similar sensitivity (74.2%) and negative predictive value (95.7%). In conclusion, corpus atrophic gastritis detection with periodic measurements of serum PG, alone or in combination with CagA-ab status, to identify high gastric cancer risk, seems to be the method best suited for mass screening in Costa Rica.
Assuntos
Citocinas/genética , Infecções por Helicobacter/complicações , Programas de Rastreamento/métodos , Pepsinogênio A/sangue , Lesões Pré-Cancerosas , Neoplasias Gástricas/prevenção & controle , Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/imunologia , Proteínas de Bactérias/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Helicobacter pylori , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético , Lesões Pré-Cancerosas/sangue , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/microbiologia , Valor Preditivo dos TestesRESUMO
BACKGROUND: Associations between Helicobacter pylori gene diversity and gastric cancer have not been reported on in Costa Rica, despite its being one of the countries with the highest gastric cancer incidence and mortality rates in the world. The aim of this study was to determine the prevalence of H. pylori cagA and vacA genes and investigate whether it could be correlated with atrophic gastritis (AG) and gastric cancer (GC) in Costa Rica. MATERIALS AND METHODS: Genomic DNAs from isolates of 104 patients classified into two groups: non-atrophic gastritis group (n = 68) and atrophic gastritis group (n = 36), were subjected to PCR-based genotyping of cagA and vacA genes and their correlation with clinical outcome was investigated. Total DNA extractions from gastric tissues of 25 H. pylori-infected gastric cancer patients were utilized for comparative purposes. RESULTS: The presence of cagA (75.3%), vacA s1b (75.3%), and vacA m1 (74.2%) was detected, and colonization by strains with different vacA genotypes in the same stomach was found in 9.7% of the patients. Age- and sex-adjusted vacA s1b and vacA m1 were associated with GC while only vacA m1 was significantly associated with AG. A tendency for association between cagA and vacA s1b, and AG was reported. CONCLUSIONS: The prevalence status of the cagA and vacA (s1/m1) genes in Costa Rica seems to fall between that found in European/North American and East Asian countries, and both cagA and vacA seem to have clinical relevance in this country.
Assuntos
Antígenos de Bactérias/genética , Proteínas de Bactérias/genética , Gastrite Atrófica/fisiopatologia , Variação Genética , Infecções por Helicobacter/complicações , Helicobacter pylori/patogenicidade , Neoplasias Gástricas/fisiopatologia , Costa Rica/epidemiologia , Feminino , Gastrite Atrófica/epidemiologia , Gastrite Atrófica/microbiologia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/genética , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Prevalência , Neoplasias Gástricas/epidemiologia , Neoplasias Gástricas/microbiologiaRESUMO
BACKGROUND: We evaluated several risk factors for gastric cancer in Costa Rican regions having contrasting gastric cancer incidence rates, despite the small dimensions of the country. METHODS: A total of 180 dyspeptic patients were classified into two groups according to the gastric cancer incidence (GCI) rate in their Costa Rican region: group A, with a high GCI rate (n = 91) and group B, with a low GCI rate (n = 89). Helicobacter pylori infection was detected by rapid urease test, Gram staining, and histological observation. Antral and corpus specimens were obtained to assess the grade of inflammation, topography of gastritis, gastric atrophy, and intestinal metaplasia by histological examination. Serum CagA antibody was measured by an antigen-specific enzyme-linked immunosorbent assay. RESULTS: There was no significant difference in H. pylori prevalence between groups A (73%) and B (63%); however, serum CagA antibody was more frequently detected in group A (79%) than in group B (54%) [P = 0.02; odds ratio (OR), 2.68]. Among patients under 60 years of age, serum CagA antibody was even more frequently detected in group A (81%) than in group B (49%) (P < 0.01; OR, 4.50). The prevalence of corpus-predominant gastritis, atrophic gastritis, and moderate/severe grades of neutrophilic infiltration was higher in serum CagA antibody-positive patients than in CagA antibody-negative patients (P = 0.003, 0.04, and 0.002, respectively). CONCLUSIONS: Infection with H. pylori possessing the cagA gene is associated with the development of severe gastric damage such as gastric atrophy, leading to gastric cancer, and probably influences the differences in GCI between Costa Rican regions.