Publicação
Caracterização e distribuição da microbiota gástrica obtida por citologia esfoliativa numa coorte portuguesa
| Resumo: | ABSTRACT Introduction: The stomach is considered an extremely hostile environment and seen, until recently, as a sterile sanctuary and protective barrier for the most distal digestive tract. Although scarce, studies have emerged with identification of the gastric microbiota and its contribution to human health, including the pathogenesis of Helicobacter pylori as a potentiator or protector of inflammation. To date, gastric microbiota has been assessed by biopsies or gastric fluid which represent limitations by being too invasive or inaccurately representing the mucosal profile. Exfoliative cytology may represent an alternative that can counteract these limitations. Therefore, this study aimed to characterize the gastric microbiota in a Portuguese cohort by exfoliative cytology sample collection. Methodology: Participants were recruited as Hospital do SAMS Endoscopy Unit, samples were taken during upper digestive endoscopy from the fundus, body and antrum by exfoliative cytology, then frozen and subsequently processed for DNA extraction and sequencing for the 16S rRNA gene. Results: Fifty participants were eligible, 76% female, aged 52.80±1.47 years. 32% had dyspeptic symptoms, 93% had mild histological lesion and 28% had Helicobacter pylori. The location with the greatest bacterial abundance was the antrum. The most abundant phyla, in the three locations, were Bacteroidetes, Proteobacteria and Firmicutes and the most abundant genera in the three locations were Prevotella, Streptococus, Haemophilus, Neisseria and Yersinia. The a- Diversity assessment did not show differences between regions, nor did the b-Diversity assessment. Assessment of microbiota and Helicobacter pylori status revealed subjects in Hp+ group had lower abundance in all stomach locations and b-Diversity differed between Hp+/Hpgroups at the genera level. Conclusion: gastric microbiota profile seems closer to the intestinal microbiota and differs between Hp+ and Hp- groups. Hp infection was accompanied by a reduction in absolute abundance in all locations. Proteobacteria was one of the most abundant phyla, but not at the expense of genera Helicobacter. Exfoliative cytology demonstrated efficacy to characterize gastric microbiota and can be used as a less invasive sample collection method. The collection site is not a limitation, althougt the antrum shows greater absolute abundance, there are no differences in diversity between gastric locations. There was a greater richness in the group with low adherence to the mediterranean diet. |
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| Autores principais: | Ferreira, Susana Maria Alves |
| Assunto: | Gastric microbiota 16S rRNA exfoliative cytology Helicobacter pylori |
| Ano: | 2024 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade Nova de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório Institucional da UNL |
| Resumo: | ABSTRACT Introduction: The stomach is considered an extremely hostile environment and seen, until recently, as a sterile sanctuary and protective barrier for the most distal digestive tract. Although scarce, studies have emerged with identification of the gastric microbiota and its contribution to human health, including the pathogenesis of Helicobacter pylori as a potentiator or protector of inflammation. To date, gastric microbiota has been assessed by biopsies or gastric fluid which represent limitations by being too invasive or inaccurately representing the mucosal profile. Exfoliative cytology may represent an alternative that can counteract these limitations. Therefore, this study aimed to characterize the gastric microbiota in a Portuguese cohort by exfoliative cytology sample collection. Methodology: Participants were recruited as Hospital do SAMS Endoscopy Unit, samples were taken during upper digestive endoscopy from the fundus, body and antrum by exfoliative cytology, then frozen and subsequently processed for DNA extraction and sequencing for the 16S rRNA gene. Results: Fifty participants were eligible, 76% female, aged 52.80±1.47 years. 32% had dyspeptic symptoms, 93% had mild histological lesion and 28% had Helicobacter pylori. The location with the greatest bacterial abundance was the antrum. The most abundant phyla, in the three locations, were Bacteroidetes, Proteobacteria and Firmicutes and the most abundant genera in the three locations were Prevotella, Streptococus, Haemophilus, Neisseria and Yersinia. The a- Diversity assessment did not show differences between regions, nor did the b-Diversity assessment. Assessment of microbiota and Helicobacter pylori status revealed subjects in Hp+ group had lower abundance in all stomach locations and b-Diversity differed between Hp+/Hpgroups at the genera level. Conclusion: gastric microbiota profile seems closer to the intestinal microbiota and differs between Hp+ and Hp- groups. Hp infection was accompanied by a reduction in absolute abundance in all locations. Proteobacteria was one of the most abundant phyla, but not at the expense of genera Helicobacter. Exfoliative cytology demonstrated efficacy to characterize gastric microbiota and can be used as a less invasive sample collection method. The collection site is not a limitation, althougt the antrum shows greater absolute abundance, there are no differences in diversity between gastric locations. There was a greater richness in the group with low adherence to the mediterranean diet. |
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