2014 - Strategic Project

Funder

Organizational Unit

Publications

In vitro cytotoxicity of ticlopidine in Hep G2 and Caco 2 cell lines

Publication . Martins, Catarina Isabel da Silva; Alba, Maria Eugénia Gallardo; Martinho, Ana Isabel de Jesus

The present dissertation is divided into 3 parts. In the Part I is described the research work conducted at the Health Sciences Research Center of the University of Beira Interior (CICS–UBI, Covilhã) with the aim of evaluating the cytotoxicity of ticlopidine and Hypericum perforatum extractin hepatic and intestinal epithelium cell lines. Ticlopidine is a prodrug mainly used in the prophylaxis of thromboembolic complications in patients with thromboembolic disease, especially if they are aspirin-intolerant. It is associated with multiple drug interactions, mostly via cytochrome P450 (CYP)-inhibition. H. perforatum has been widely used as an antidepressant, anti-inflammatory and antimicrobial agent, being considered, however, responsible for numerous herb-drug interactions due to the induction of CYP enzymes and P-glycoprotein expression. Given the predisposition of both these compounds to induce interactions when co-administered with other substances, it was considered relevant to study their cytotoxicity, alone and in combination, in hepatic – Hep G2 – and intestinal epithelium – Caco 2 – cell lines. The cells were incubated with various concentrations of ticlopidine and/or H. perforatum extract at various periods of time and the putative cytotoxicity induced by each incubation condition was assessed through cellular viability (MTT) assays. Overall, the results showed that ticlopidine may be cytotoxic in both Hep G2 and Caco 2 cells, depending on its concentration and period of incubation, and that the simultaneous incubation of cells with both the compounds promotes a similar pattern to that observed when cells are incubated with the extract alone and it is dose-, time- and cell line-dependent. The Part II refers to the hospital pharmacy internship performed at the Istituti Fisioterapici Ospedalieri, in Rome, between February 2nd and April 29th 2015. Finally, the Part III refers to the community pharmacy internship carried out in the Nunes Feijão Pharmacy, near Barreiro, between May 11th and August 10th 2015.

2015-11-12Master thesis

Open access

PVP-coated silver nanoparticles showing antifungal improved activity against dermatophytes

Publication . Silva, Stephane Edgar da; Saraiva, Sofia M; Miguel, Sónia P.; Correia, Ilídio Joaquim Sobreira

Fungal infections affecting human beings have increased during the last years and the currently available treatments, when administered for long periods, trigger microbial resistance. Such demands the development of new viable therapeutic alternatives. Silver is known since the antiquity by its antimicrobial properties and, herein, it was used to produce two types of nanoparticles (NPs), uncoated and coated with polyvinylpyrrolidone (PVP), which were aimed to be used in fungal infection treatment. NPs properties were characterized by Transmission electron microscopy, X-ray diffraction, UV–Vis, Dynamic light scattering, Fourier transform infrared, and Energy-dispersive X-ray spectroscopy. Furthermore, in vitro studies were also performed to evaluate NPs cytotoxic profile and antifungal activity. The results obtained revealed that the produced nanoparticles are biocompatible and have a good potential for being used in the treatment of common skin infections caused by Trichophyton rubrum and Trichophyton mentagrophytes, being PVP-coated silver NPs the most suitable ones.

2014-11-05Journal article

Restricted access

Preparation of end-capped pH-sensitive mesoporous silica nanocarriers for on-demand drug delivery

Publication . Moreira, André; Gaspar, Vítor Manuel Abreu; Costa, Elisabete C.; Diogo, Duarte Miguel de Melo; Machado, Paulo Filipe Brito; Paquete, Catarina; Correia, Ilídio Joaquim Sobreira

Nanocarriers with a pH responsive behavior are receiving an ever growing attention due to their potential for promoting on-demand drug release and thus increase the therapeutic effectiveness of anti-tumoral pharmaceutics. However, the majority of these systems require costly, time-consuming and complex chemical modifications of materials or drugs to synthesize nanoparticles with pH triggered release. Herein, the development of dual drug loaded pH-responsive mesoporous silica nanoparticles (MSNs) with a calcium carbonate-based coating is presented as an effective alternative. This innovative approach allowed the loading of a non-steroidal anti-inflammatory drug (Ibuprofen) and Doxorubicin, with high efficiency. The resulting dual drug loaded MSNs have spherical morphology and a mean size of 171 nm. Our results indicate that under acidic conditions the coating disassembles and the drugs are rapidly released, whereas at physiologic pH the release is slower and gradually increases with time. Furthermore, an improved cytotoxic effect was obtained for Doxorubicin–Ibuprofen MSNs coated with CaCO3 in comparison with non-coated particles. The cytotoxic effect of dual loaded carbonate coated particles, was similar to that of Doxorubicin + Ibuprofen free drug administration at 72 h, even with the delivery of a significantly lower amount of drug by MSNs-CaCO3. These results suggest that the carbonate coating of MSNs is a promising approach to create a pH-sensitive template for a delivery system with application in cancer therapy.

2014-09-16Journal article

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Chitosan/arginine–chitosan polymer blends for assembly of nanofibrous membranes for wound regeneration

Publication . Antunes, Bernardo Paiva; Moreira, André; Gaspar, Vítor Manuel Abreu; Correia, Ilídio Joaquim Sobreira

Frequently, skin is subjected to damaging events, such as deep cuts, burns or ulcers, which may compromise the integrity of this organ. To overcome such lesions, different strategies have been employed. Among them, wound dressings aimed to re-establish skin native properties and decreased patient pain have been pursued for a long time. Herein, an electrospun membrane comprised by deacetylated/arginine modified chitosan (CH-A) was produced to be used as a wound dressing. The obtained results showed that the membrane has a highly hydrophilic and porous three-dimensional nanofibrous network similar to that found in human native extracellular matrix. In vitro data indicate that human fibroblasts adhere and proliferate in contact with membranes, thus corroborating their biocompatibility. This nanofiber-based biomaterial also demonstrated bactericidal activity for two bacterial strains. In vivo application of CH-A nanofibers in full thickness wounds resulted in an improved tissue regeneration and faster wound closure, when compared to non-modified membranes. Such findings support the suitability of using this membrane as a wound dressing in a near future.

2015-05-12Journal article

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Impact of cardiac resynchronization therapy on circulating IL-17 producing cells in patients with advanced heart failure

Publication . Martins, Sílvia; Carvalheiro, Tiago; Laranjeira, Paula; Martinho, António; Elvas, Luís; Gonçalves, Lino; Tomaz, C. T.; António, Natália; Paiva, Artur

IL-17-producing T cells have been implicated in the inflammatory milieu of chronic heart failure (CHF), which implies a dismal prognosis in affected patients. The aim of this study was to evaluate the impact of cardiac resynchronization therapy (CRT) on the frequency and functional activity of Th17 and Tc17 cells, as well as, on IL-17 mRNA expression in patients with CHF.

2019Journal article

Open access