Armando Sierralta

(1) Background: Gastric cancer, the fourth most common cause of death from tumors in the world, is closely associated with Helicobacter pylori. Timely diagnosis, therefore, is essential to achieve a higher survival rate. In Chile, deaths from gastric cancer are high, mainly due to late diagnosis. Progranulin has reflected the evolution of some cancers, but has been poorly studied in gastric lesions. Aiming to understand the role of progranulin in H. pylori infection and its evolution in development of gastric lesions, we evaluated the genic expression of progranulin in gastric tissue from infected and non-infected patients, comparing it according to the epithelial status and virulence of H. pylori strains. (2) Methods: The genic expression of progranulin by q-PCR was quantified in gastric biopsies from Chilean dyspeptic patients (n = 75) and individuals who were uninfected (n = 75) by H. pylori, after receiving prior informed consent. Bacteria were grown on a medium Columbia agar with equine-blood 7%, antibiotics (Dent 2%, Oxoid^TM), in a microaerophilic environment, and genetically characterized for the ureC, vacA, cagA, and iceA genes by PCR. The status of the tissue was determined by endoscopic observation. (3) Results: Minor progranulin expression was detected in atrophic tissue, with a sharp drop in the tissue colonized by H. pylori that carried greater virulence, VacAs1m1⁺CagA⁺IceA1⁺. (4) Conclusions: Progranulin shows a differential behavior according to the lesions and virulence of H. pylori, affecting the response of progranulin against gastric inflammation.

Helicobacter pylori is the main bacteria associated with gastroduodenal diseases. Recent studies have reported that gastric microbiota might be modified by the H. pylori colonization, favoring gastric lesions′ development. In Chile, the region of La Araucanía concentrates a high risk of gastric cancer associated with Helicobacter pylori colonization, rurality, poverty, and Mapuche ethnicity. Hence, we aimed to identify the culturable gastric microbiota and characterize its variability at different stages of epithelial injury, based on its H. pylori colonization in dyspeptic patients from this Chilean region. Microaerophilic bacteria strains were isolated from antrum biopsies of 155 dyspeptic patients′ biopsies and identified using MALDI-TOF MS or 16sRNA gene sequencing for non-pylori species identification, and UreC gene amplification for H. pylori confirmation. We found 48 species from 18 families, mainly belonging to Neisseriaceae (21.3%), Streptococcaceae (20.0%), Actynomicetaceae (9.0%), Enterobacteriaceae, and Lactobacillaceae (4.5%); however, Streptococcaceae and Actinomycetaceae families showed a significant reduction in samples infected with H. pylori, along with a considerably lower diversity of species. Our results revealed a microbiota modification due to H. pylori colonization associated with the gastric epithelial state, suggesting a potential microbiota role for developing and progressing gastric diseases.

Helicobacter pylori colonizes half of the human population. Age, ethnicity, and socioeconomic status are factors that influence the prevalence of the infection. This is important in southern Chile, one of the most unequal regions in the world, where a significant difference in the health access of the population occurs due to the existence of two competing health systems. Moreover, in the last few years, current protocols of H. pylori eradication have shown high rates of resistance with reduced therapeutic efficacy. This study reported the epidemiology of infection and attempted to identify divergent points among the population beneficiaries of the two health care schemes in southern Chile. Biopsies from public (n = 143) and private (n = 86) health systems were studied. At the same time, clinical and sociodemographic factors were evaluated. H. pylori strains were obtained from gastric biopsies for culture and molecular testing. Antibiotic susceptibility was determined by the agar dilution method. Differences about ethnicity, rural residence, and education (p ≤ 0.05) were observed between beneficiaries of the two health systems. The prevalence of H. pylori was 45%, with no significant differences regardless of the socioeconomic conditions. The only identified risk factor associated with H. pylori infection was Mapuche ethnicity (OR (odds ratio) = 2.30). H. pylori showed high resistance rates, particularly against clarithromycin (40%), levofloxacin (43.1%), and metronidazole (81.8%). This study highlighted the importance of Mapuche ancestry as a risk factor in southern Chile and emphasized the need to search for new eradication strategies as well as further studies evaluating therapeutic efficacy.