Rui M Ferreira

University of Porto, Oporto, Porto, Portugal

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Publications (16)118.99 Total impact

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    ABSTRACT: Helicobacter pylori colonizes the human stomach and increases the risk for peptic ulcer disease and gastric carcinoma. H. pylori upregulates the expression and activity of several matrix metalloproteinases (MMPs) in cell lines and in the gastric mucosa. The aim of this study was to explore the mechanisms leading to up-regulation of MMP-10 in gastric epithelial cells induced by H. pylori. Infection of gastric cells with H. pylori led to an increase in MMP-10 mRNA, protein secretion, and activity. cagA-knockout or CagA-phosphorylation defective mutants failed to increase MMP-10 expression. These results were confirmed in infection experiments with clinical isolates with known cagA status and in human gastric biopsies. Treatment of cells with chemical inhibitors of EGFR and Src abrogated H. pylori-induced MMP-10 expression. Inhibitors of ERK1/2 and JNK abolished or significantly decreased H. pylori-induced MMP-10 expression, respectively, whereas inhibition of p38 had no effect. Finally, inhibition of MMP-10 expression by siRNA led to a decrease in the gastric cell invasive phenotype mediated by the infection. In conclusion, H. pylori CagA-positive strains stimulate MMP-10 expression. MMP-10 modulation occurs via EGFR activation, in a process that involves Src, ERK and JNK pathways. MMP-10 may be implicated in H. pylori-mediated extracellular matrix remodeling.
    Full-text · Article · Jan 2016 · The Journal of Infectious Diseases
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    ABSTRACT: Heterogeneity at the Helicobacter pylori cagA gene promoter region has been linked to variation in CagA expression and gastric histopathology. Here, we characterized the cagA promoter and expression in 46 H. pylori strains from Portugal. Our results confirm the relationship between cagA promoter region variation and protein expression originally observed in strains from Colombia. We observed that individuals with intestinal metaplasia were all infected with H. pylori strains containing a specific cagA motif. Additionally, we provided novel functional evidence that strain-specific sequences in the cagA promoter region and CagA expression levels influence interleukin 8 secretion by the host gastric epithelial cells.
    No preview · Article · Sep 2015 · The Journal of Infectious Diseases
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    ABSTRACT: Helicobacter pylori exploits host glycoconjugates to colonize the gastric niche. Infection can persist for decades promoting chronic inflammation, and in a subset of individuals lesions can silently progress to cancer. This study shows that H. pylori chronic infection and gastric tissue inflammation result in a remodeling of the gastric glycophenotype with increased expression of sialyl-Lewis a/x antigens due to transcriptional up-regulation of the B3GNT5, B3GALT5, and FUT3 genes. We observed that H. pylori infected individuals present a marked gastric local pro-inflammatory signature with significantly higher TNF-α levels and demonstrated that TNF-induced activation of the NF-kappaB pathway results in B3GNT5 transcriptional up-regulation. Furthermore, we show that this gastric glycosylation shift, characterized by increased sialylation patterns, favors SabA-mediated H. pylori attachment to human inflamed gastric mucosa. This study provides novel clinically relevant insights into the regulatory mechanisms underlying H. pylori modulation of host glycosylation machinery, and phenotypic alterations crucial for life-long infection. Moreover, the biosynthetic pathways here identified as responsible for gastric mucosa increased sialylation, in response to H. pylori infection, can be exploited as drug targets for hindering bacteria adhesion and counteract the infection chronicity. Copyright © 2015. Published by Elsevier B.V.
    Full-text · Article · Jul 2015 · Biochimica et Biophysica Acta
  • Rui M Ferreira · José C Machado · Ceu Figueiredo
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    ABSTRACT: Helicobacter pylori infection is the major etiological factor of gastric carcinoma. This disease is the result of a long, multistep, and multifactorial process, which occurs only in a small proportion of patients infected with H. pylori. Gastric carcinoma development is influenced by host genetic susceptibility factors, environmental factors, and H. pylori virulence. H. pylori is genetically highly variable, and variability that affects H. pylori virulence factors may be useful to identify strains with different degrees of pathogenicity. This review will focus on VacA and CagA that have polymorphic regions that impact their functional properties. The characterization of H. pylori vacA and cagA-associated could be useful for identifying patients at highest risk of disease, who could be offered H. pylori eradication therapy and who could be included in programs of more intensive surveillance in an attempt to reduce gastric carcinoma incidence. Copyright © 2014 Elsevier Ltd. All rights reserved.
    No preview · Article · Dec 2014 · Baillière&#x027 s Best Practice and Research in Clinical Gastroenterology
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    ABSTRACT: First-degree relatives (FDR) of early-onset gastric cancer (EOGC) is presumed to be a population with a distinct molecular and phenotypic profile, regarding the prevalence of gastric premalignant conditions and the association with Helicobacter pylori infection and host proinflammatory gene polymorphisms. A case-control study was conducted with FDR of EOGC patients (n = 103) and age and gender matched controls (n = 101; ranging from spouses to neighbors and dyspeptics). Upper endoscopy was performed, Operative Link on Gastritis Assessment (OLGA) system used for staging and H. pylori (cagA and vacA) and host IL1B-511, IL1RN intron2 VNTR and IFNGR1-56 genotyping. Seventy percent of cases showed atrophy, while 19 % presented with high-stage gastritis (OLGA stage III or IV) (p < 0.001); gastric dysplasia was present in seven cases (vs none in controls) (p = 0.007). In cases, H. pylori was present in 82 % (vs 62 % in controls; p = 0.004) with vacA s1 and vacA m1 + strains significantly associated with the presence of atrophy; individuals homozygous for IL1B-511*T present a significantly higher risk for dysplasia. An increased global prevalence of IFNGR1-56*T/*T polymorphism (37 % in cases vs 24 % in controls; p = 0.03) was observed with no association with atrophic changes or dysplasia. All trends observed were kept when comparing FDR of EOGC with spouses, neighbors, or dyspeptic controls. We demonstrated that FDR of EOGC patients have an increased prevalence of high-risk OLGA stages and dysplasia that seem to be associated with high virulence H. pylori strains and pro-inflammatory host genotypes, including a possible population-specific risk marker. FDR of EOGC patients may merit specific management through endoscopic and histopathological adequate assessment of gastric mucosa and surveillance.
    Full-text · Article · Jul 2013 · Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin
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    ABSTRACT: Here, we evaluated a previously established peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) method as a new diagnostic test for Helicobacter pylori clarithromycin resistance detection in paraffin-embedded gastric biopsy specimens. Both a retrospective study and a prospective cohort study were conducted to evaluate the specificity and sensitivity of a PNA-FISH method to determine H. pylori clarithromycin resistance. In the retrospective study (n = 30 patients), full agreement between PNA-FISH and PCR-sequencing was observed. Compared to the reference method (culture followed by Etest), the specificity and sensitivity of PNA-FISH were 90.9% (95% confidence interval [CI], 57.1% to 99.5%) and 84.2% (95% CI, 59.5% to 95.8%), respectively. In the prospective cohort (n = 93 patients), 21 cases were positive by culture. For the patients harboring clarithromycin-resistant H. pylori, the method showed sensitivity of 80.0% (95% CI, 29.9% to 98.9%) and specificity of 93.8% (95% CI, 67.7% to 99.7%). These values likely represent underestimations, as some of the discrepant results corresponded to patients infected by more than one strain. PNA-FISH appears to be a simple, quick, and accurate method for detecting H. pylori clarithromycin resistance in paraffin-embedded biopsy specimens. It is also the only one of the methods assessed here that allows direct and specific visualization of this microorganism within the biopsy specimens, a characteristic that allowed the observation that cells of different H. pylori strains can subsist in very close proximity in the stomach.
    Full-text · Article · Apr 2013 · Journal of clinical microbiology
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    ABSTRACT: The present report describes a novel method for genotyping the virulence-associated vacA intermediate (i) region of Helicobacter pylori in archive material. vacA i-region genotypes as determined by the novel method were completely concordant with those of sequence analysis and with those of functional vacuolation activity. The method was further validated directly in gastric biopsy specimens of 386 H. pylori-positive cases, and effective characterization of the vacA i region was obtained in 191 of 192 (99.5%) frozen and in 186 of 194 (95.9%) formalin-fixed paraffin-embedded gastric biopsy specimens, respectively. The genotyping method was next used to address the relationship between the vacA genotypes and the cagA status. The vacA i1 genotype was associated with vacA s1 (where s indicates signal region), vacA m1 (where m indicates middle region), and cagA-positive genotypes (P < 0.0001), while the vacA i2 genotype was closely related with vacA s2, vacA m2, and cagA-negative genotypes (P < 0.0001). The relationship between H. pylori vacA i-region genotypes and gastric disease development was subsequently evaluated in the Portuguese population. Patients infected with vacA i1 strains showed an increased risk for gastric atrophy and for gastric carcinoma, with odds ratios of 8.0 (95% confidence interval [CI], 2.3 to 27) and of 22 (95% CI, 7.9 to 63), respectively. Taken together, the results show that this novel H. pylori vacA i-region genotyping method can be applied directly to archive material, providing a fast evaluation of strain virulence determinants without the need of culture. The results further emphasize that the characterization of the vacA i region may be useful to identify patients at higher risk of gastric carcinoma development.
    Full-text · Article · Oct 2012 · Journal of clinical microbiology

  • No preview · Article · May 2012 · Gastroenterology
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    ABSTRACT: H. pylori drug-resistant strains and non-compliance to therapy are the major causes of H. pylori eradication failure. For some bacterial species it has been demonstrated that fatty acids have a growth inhibitory effect. Our main aim was to assess the ability of docosahexaenoic acid (DHA) to inhibit H. pylori growth both in vitro and in a mouse model. The effectiveness of standard therapy (ST) in combination with DHA on H. pylori eradication and recurrence prevention success was also investigated. The effects of DHA on H. pylori growth were analyzed in an in vitro dose-response study and n in vivo model. We analized the ability of H. pylori to colonize mice gastric mucosa following DHA, ST or a combination of both treatments. Our data demonstrate that DHA decreases H. pylori growth in vitro in a dose-dependent manner. Furthermore, DHA inhibits H. pylori gastric colonization in vivo as well as decreases mouse gastric mucosa inflammation. Addition of DHA to ST was also associated with lower H. pylori infection recurrence in the mouse model. In conclusion, DHA is an inhibitor of H. pylori growth and its ability to colonize mouse stomach. DHA treatment is also associated with a lower recurrence of H. pylori infection in combination with ST. These observations pave the way to consider DHA as an adjunct agent in H. pylori eradication treatment.
    Full-text · Article · Apr 2012 · PLoS ONE
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    ABSTRACT: To characterize the variation in virulence of Helicobacter pylori associated with CagA Glu-Pro-Ile-Tyr-Ala (EPIYA) motifs, and to explore its relationship with the histopathological features of chronic gastritis and with the development of gastric carcinoma. A total of 169 H. pylori-infected patients with chronic gastritis and gastric carcinoma were studied. The presence of cagA and the number and type of EPIYA motifs were determined by polymerase chain reaction. Infection with strains harbouring two or more CagA EPIYA C motifs was associated with the presence of surface epithelial damage, and with atrophic gastritis and gastric carcinoma. The magnitude of risk for atrophic gastritis and gastric carcinoma increased with increasing number of EPIYA C motifs: strains with one EPIYA C motif conferred a risk (odds ratio [OR]) of 7.3 [95% confidence interval (CI) 2.1-25] for atrophic gastritis, whereas strains with two or more EPIYA C motifs conferred a risk (OR) of 12 (95% CI 2.5-58); strains with one EPIYA C motif conferred a risk (OR) of 17 (95% CI 5.4-55) for gastric carcinoma, whereas strains with two or more EPIYA C motifs conferred a risk (OR) of 51 (95% CI 13-198). Characterization of the number of H. pylori EPIYA C motifs is important in better defining gastric carcinoma risk.
    No preview · Article · Feb 2012 · Histopathology
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    ABSTRACT: The American Journal of Gastroenterology is published by Nature Publishing Group (NPG) on behalf of the American College of Gastroenterology (ACG). Ranked the #1 clinical journal covering gastroenterology and hepatology*, The American Journal of Gastroenterology (AJG) provides practical and professional support for clinicians dealing with the gastroenterological disorders seen most often in patients. Published with practicing clinicians in mind, the journal aims to be easily accessible, organizing its content by topic, both online and in print. www.amjgastro.com, *2007 Journal Citation Report (Thomson Reuters, 2008)
    No preview · Article · Jan 2012 · The American Journal of Gastroenterology
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    ABSTRACT: Triple therapy is the gold standard treatment for Helicobacter pylori eradication from the human stomach, but increased resistance to clarithromycin became the main factor of treatment failure. Until now, fastidious culturing methods are generally the method of choice to assess resistance status. In this study, a new genotypic method to detect clarithromycin resistance in clinical samples, based on fluorescent in situ hybridization (FISH) using a set of peptide nucleic acid probes (PNA), is proposed. The set of probes targeting the point mutations responsible for clarithromycin resistance was applied to H. pylori suspensions and showed 100% sensitivity and specificity (95% CI, 79.9-100 and 95% CI, 71.6-100 respectively). This method can also be amenable for application to gastric biopsy samples, as resistance to clarithromycin was also detected when histological slides were tested. The optimized PNA-FISH based diagnostic method to detect H. pylori clarithromycin resistance shown to be a very sensitive and specific method for the detection of clarithromycin resistance in the H. pylori smears and also proved to be a reliable method for the diagnosis of this pathogen in clinical samples and an alternative to existing plating methods.
    Full-text · Article · May 2011 · BMC Microbiology
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    ABSTRACT: The transmission of the gastric pathogen Helicobacter pylori involves the oral route. Molecular techniques have allowed the detection of H. pylori DNA in samples of the oral cavity, although culture of H. pylori from these type of samples has been sporadic. Studies have tried to demonstrate the presence of H. pylori in adenotonsillar tissue, with contradictory results. Our aim was to clarify whether the adenotonsillar tissue may constitute an extra gastric reservoir for H. pylori. Sixty-two children proposed for adenoidectomy or tonsillectomy were enrolled. A total of 101 surgical specimens, 55 adenoid and 46 tonsils, were obtained. Patients were characterized for the presence of anti-H. pylori antibodies by serology. On each surgical sample rapid urease test, immunohistochemistry, fluorescence in situ hybridization (FISH) with a peptide nucleic acid probe for H. pylori, and polymerase chain reaction-DNA hybridization assay (PCR-DEIA) directed to the vacA gene of H. pylori were performed. Thirty-nine percent of the individuals had anti-H. pylori antibodies. Rapid urease test was positive in samples of three patients, all with positive serology. Immunohistochemistry was positive in samples of two patients, all with negative serology. All rapid urease test or immunohistochemistry positive cases were negative by FISH. All samples tested were negative when PCR-DEIA for H. pylori detection was used directly in adenotonsillar specimens. The adenotonsillar tissue does not constitute an extra gastric reservoir for H. pylori infection, at least a permanent one, in this population of children. Moreover, techniques currently used for detecting gastric H. pylori colonization are not adequate to evaluate infection of the adenotonsillar tissues.
    Full-text · Article · May 2010 · International journal of pediatric otorhinolaryngology

  • No preview · Article · May 2009 · Gastroenterology

  • No preview · Article · May 2009 · Gastroenterology

  • No preview · Article · Apr 2008 · Gastroenterology

Publication Stats

111 Citations
118.99 Total Impact Points

Institutions

  • 2009-2015
    • University of Porto
      • Institute of Molecular Pathology and Immunology (IPATIMUP)
      Oporto, Porto, Portugal
  • 2012
    • University of Nottingham
      • Nottingham Hearing Biomedical Research Unit
      Nottigham, England, United Kingdom