Browsing by Author "Pereira, Teresa"
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- Cox-2 inhibition with nutraceuticals: a new therapeutic approach against Helicobacter pylori infectionPublication . Santos, António Mário; Oleastro, Mónica; Lopes, Teresa; Pereira, Teresa; Seixas, Elsa; Chaves, Paula; Machado, Jorge; Guerreiro, António SousaAccumulated evidence in humans and animals shows that H. pylori up-regulate the expression of cyclooxygenase (COX)-2 both at mRNA and protein levels which might be one of the mechanisms leading to several gastric diseases. Aim: To study the expression of COX-2 on mice gastric mucosa during long-term treatment with two nutraceuticals: curcumin and synbiotic 2000 on H. pylori experimental chronic infection. Materials and Methods: We infected 45 C57BL/6 mice with SS1 – H. pylori strain. After infection confirmation by 13C-urea breath test mice where then treated with either PBS, curcumin (10 mg/mouse) or Synbiotic 2000 (50 mg/ mouse), three times per week. Five mice from each treatment group were euthanized at week 6, 18 and 27. Gastric samples were removed for COX-2 immunohistochemistry analysis. Results: All the 45 mice were Hp positive by 13C-urea breath test and immunohistochemistry. In the PBS group the production of COX-2 was significantly up-regulated at week 6 (area of positive immunostaining 393–544 · 103 pixels), 18 (area of positive immunostaining 242–614 · 103 pixels) and 27 week (area of positive immunostaining 129–175 · 103 pixels). The treatment with either curcumin or synbiotic significantly decreased the expression of COX-2 at all time points. Conclusions: These results suggest the therapeutic usefulness of both nutraceuticals on COX-2 inhibition during chronic experimental mice H. pylori infection. The supplementation of diet in humans with curcumin or Synbiotic 2000 may be a novel therapeutic approach against gastric inflammation induced by Hp infection.
- Helicobacter pylori infection: the role of intestinalPublication . Machado, Jorge; Gato, Inês; Lopes, Teresa; Pereira, Teresa; Santos, Mário; Oleastro, Mónica; Chaves, Paula; Guerreiro, AntónioIntestinal microbiota may influence inflammation in the host. The aim of the present study was to explore the role of modulation of intestinal microbiota in the outcome in the Helicobacter pylori (Hp) gastric inflammation. Twenty five C57BL/6 male mice were separated in three groups: Control group (CG) n = 5 Infected group (IG) n = 10 and Synbiotic 2000TM (SG) n = 10. CG received PBS by gavage; IG and SG were inoculated intragastrically with H. pylori SS1 cell suspension (109 CFU/mL). Then, mice were treated either with PBS (CG and IG) or Synbiotic 2000TM (SG). Five mice from each group were sacrificed at week 6 and the other at week 18. At each time samples were collected from: gastric tissue to immunohistochemistry and histological evaluation (HE) and faeces to evaluate intestinal microbiota composition by FISH, targeting 14 bacterial groups. IG and SG groups were H. pylori positive by immunohistochemistry. Microbiota analysis: In IG there were significant changes in the microbiota composition, comparing to CG. At week 6 there were changes in 12 of 14 (85.7%) bacterial groups, while at week 18 there was a change in 6/14 (42.9%). In SG, there were changes in 7/14 (50.0%) at week 6, and in 4/14 (28.6%) at week 18, comparing to CG. Histology: IG at weeks 6 and 18 has 40% (2/5) of intramucosal inflammation and SG at the same end points has 0% (0/5). These results suggest that modulation of the intestinal microbiota by Synbiotic 2000TM may influence the outcome of Hp gastric inflammation.
- RAC1b overexpression stimulates proliferation and NF-kB-mediated anti-apoptotic signaling in thyroid cancer cellsPublication . Faria, Márcia; Matos, Paulo; Pereira, Teresa; Cabrera, Rafael; Cardoso, Bruno A.; Bugalho, Maria João; Silva, Ana LuísaOverexpression of tumor-associated RAC1b has been recently highlighted as one of the most promising targets for therapeutic intervention in colon, breast, lung and pancreatic cancer. RAC1b is a hyperactive variant of the small GTPase RAC1 and has been recently shown to be overexpressed in a subset of papillary thyroid carcinomas associated with unfavorable outcome. Using the K1 PTC derived cell line as an in vitro model, we observed that both RAC1 and RAC1b were able to induce a significant increase on NF-kB and cyclin D1 reporter activity. A clear p65 nuclear localization was found in cells transfected with RAC1b-WT, confirming NF-kB canonical pathway activation. Consistently, we observed a RAC1b-mediated decrease in IκBα (NF-kB inhibitor) protein levels. Moreover, we show that RAC1b overexpression stimulates G1/S progression and protects thyroid cells against induced apoptosis, the latter through a process involving the NF-kB pathway. Present data support previous findings suggesting an important role for RAC1b in the development of follicular cell-derived thyroid malignancies and point out NF-kB activation as one of the molecular mechanisms associated with the pro-tumorigenic advantage of RAC1b overexpression in thyroid carcinomas.
- Role of 13C-urea breath test in experimental model of Helicobacter pylori infection in micePublication . Santos, António Mário; Lopes, Teresa; Oleastro, Mónica; Chaves, Paula; Cordeiro, Rita; Ferreira, Maria; Pereira, Teresa; Machado, Jorge; Guerreiro, António SousaBACKGROUND: Animal models have been widely used to study Helicobacter pylori infection. Evaluation of H. pylori infection status following experimental inoculation of mice usually requires euthanasia. The (13) C-urea breath test ((13) C-UBT) is both sensitive and specific for detection of H. pylori in humans. Thus, it would be very useful to have such a test with the same accuracy for the follow-up of this infection in animal models of gastric infection. Accordingly, the purpose of this study was to develop and evaluate a (13) C-UBT method for following the course of H. pylori infection in a mouse model. MATERIAL AND METHODS: A total of 50 female C57BL/6 mice were gavaged three times with either 10(8) colony-forming units of H. pylori (n=29) or saline solution only (n=21). After 2 months of infection, mice were fasted for 14 hours and (13) C-UBT was performed using 300 μg of (13) C-urea. The mice were killed, and the stomach was removed and processed for immunohistochemistry and PCR. RESULTS: The optimal time for breath sample collection in mice was found to be 15 minutes. The (13) C-UBT cutoff was set at 3.0‰ δPDB. Using PCR as the gold standard, the sensitivity of (13) C-UBT and immunohistochemistry was 96.6 and 72.4%, respectively, while the specificity was 85.7 and 95.2%, respectively. CONCLUSIONS: (13) C-UBT was shown to be a reliable method for the detection of H. pylori infection in C57BL/6 mice and was even more accurate than immunohistochemistry. The use of (13) C-UBT in the mouse model of H. pylori infection can be very useful to detect the bacterium without the need to kill the animals in long-term time course studies.