Cardiotoxicidade do isoproterenol e dos produtos da sua oxidação : Estudos mecanísticos em suspensões de cardiomiócitos isolados de rato adulto

Dissertação de Doutoramento em Toxicologia apresentada à Faculdade de Farmácia da Universidade do PortoAs catecolaminas desempenham um papel fisiológico fundamental na neurotransmissão. No entanto, quando utilizadas como agentes terapêuticos, ou, então, quando os seus níveis aumentam durante fenómenos patológicos como o feocromocitoma, a isquemia-reperfusão e o stress psicossocial, as catecolaminas podem desenvolver toxicidade ao nível cardiovascular e, mais especificamente, ao nível cardíaco. Para o estudo experimental da cardiotoxicidade das catecolaminas, um dos compostos mais utilizados como modelo é a catecolamina sintética isoproterenol.Estão descritos diversos mecanismos para a cardiotoxicidade exercida pelo isoproterenol. No entanto, a sua actividade b-adrenérgica e o stress oxidativo resultante da sua oxidação são as vias propostas mais referidas por diferentes autores. Esta dissertação tem como objectivo contribuir para o esclarecimento do mecanismo de cardiotoxicidade das catecolaminas, em particular do isoproterenol, quando este é mediado pelo fenómeno de oxidação destas moléculas.Para a concretização do objectivo realizaram-se estudos in vivo e in vitro, para os quais foram desenvolvidas ou adaptadas técnicas experimentais. Nas técnicas experimentais destacam-se: a obtenção de suspensões de cardiomiócitos, tolerantes ao Ca2+, isolados de rato adulto; a quantificação simultânea da glutationa reduzida e oxidada em células isoladas, por HPLC com detecção electroquímica; a determinação dos níveis de catecolaminas e respectivos aminocromos em amostras biológicas, por HPLC com detecção por fotodíodos.Nos estudos in vivo: quantificou-se o isoproterenol no plasma e coração de rato adulto, 15 minutos após terem sido injectadas doses tóxicas desta catecolamina; quantificou-se o adrenocromo no sangue de rato adulto, 5, 15 e 25 minutos após terem sido injectadas doses tóxicas deste aminocromo.Nos estudos in vitro: estudou-se a oxidação do isoproterenol a isoprenocromo nas suspensões de cardiomiócitos, tolerantes ao Ca2+, isolados de rato adulto. Nest ..

Aulas Invertidas: relato de um estudo transdisciplinar

A apropriação da aula invertida como dispositivo pedagógico permite a tradução do conhecimento científico numa linguagem pedagógica, permitindo aos estudantes diversos envolverem-se no processo ensino-aprendizagem e valorizar o conhecimento veiculado. As três experiências relatadas realizaram-se em unidades curriculares dos cursos de Ciências da Educação, Ciências Farmacêuticas e Engenharia Civil da U.Porto e tiveram em conta objetivos traçados para as três unidades curriculares. A análise dos resultados baseia-se num inquérito por questionário e os principais resultados mostram o prosseguimento dos objetivos traçados e a criação de um espaço de reflexão crítica por parte dos estudantes. O aprofundamento do conceito de aula invertida, enquanto dispositivo pedagógico em 'diálogo' com diversas áreas científicas, consistirá na avaliação de experiências pedagógicas futuras com recurso a estratégias de investigação multimétodo

Exploring the Multi-Target Performance of Mitochondriotropic Antioxidants against the Pivotal Alzheimer’s Disease Pathophysiological Hallmarks

Alzheimer disease (AD) is the most common neurodegenerative disease featuring progressive and degenerative neurological impairments resulting in memory loss and cognitive decline. The specific mechanisms underlying AD are still poorly understood, but it is suggested that a deficiency in the brain neurotransmitter acetylcholine, the deposition of insoluble aggregates of fibrillar β-amyloid 1–42 (Aβ42), and iron and glutamate accumulation play an important role in the disease progress. Despite the existence of approved cholinergic drugs, none of them demonstrated effectiveness in modifying disease progression. Accordingly, the development of new chemical entities acting on more than one target is attracting progressively more attention as they can tackle intricate network targets and modulate their effects. Within this endeavor, a series of mitochondriotropic antioxidants inspired on hydroxycinnamic (HCA’s) scaffold were synthesized, screened toward cholinesterases and evaluated as neuroprotectors in a differentiated human SH-SY5Y cell line. From the series, compounds 7 and 11 with a 10-carbon chain can be viewed as multi-target leads for the treatment of AD, as they act as dual and bifunctional cholinesterase inhibitors and prevent the neuronal damage caused by diverse aggressors related to protein misfolding and aggregation, iron accumulation and excitotoxicityThis work was funded by FEDER funds through the Operational Programme Competitiveness Factors-COMPETE and national funds by FCT-Foundation for Science and Technology under research grants (UID/QUI/00081, NORTE-01-0145-FEDER-000028, PTDC/DTP-FTO/2433/2014, PTDC/BIA-MOL/28607/2017, POCI-01-0145-FEDER-028607). S. Benfeito and C. Fernandes grants are supported by FCT, POPH and QREN. The authors also thank the COST action CA15135 for supportS

Adrenaline and Noradrenaline: Partners and Actors in the Same Play"

info:eu-repo/semantics/publishedVersio

Halochromic properties of a 5-aminoimidazole-4-carboxamidrazone and its application to wool

The application of stimuli-responsive molecules in textiles is an important field due to its potential in various areas of flexible sensing technology. In particular, pH plays an important role in nature, humans, and several processes. The pH of body fluids is one of the best indicators of disturbed health conditions. Thus, the development of textiles with halochromic properties has been increasingly attractive to display in real-time pH variations. Wool is one of the most important natural fibres because of its warmth and comfort. However, the dyeing process is costly and high energy-consuming. In this work, the halochromic properties under different buffers (acetate, phosphate, Britton-Robinson, artificial sweat, and artificial wound exudate) of a previously synthesized 5-aminoimidazole-4-carboxamidrazone were studied. Moreover, the first attempt to dye a wool knitted fabric with this molecule at a low temperature was performed. The developed material showed interesting halochromic properties (colourless in acidic pH and blue colour in the alkaline pH), even using artificial body fluids.This work was funded by European Regional Development Fund through the Operational Competitiveness Program and the National Foundation for Science and Technology of Portugal (FCT) under the projects UID/CTM/00264/2021, UID/QUI/00686/2020, MEDCOR PTDC/CTMTEX/1213/2020 and Ph.D. scholarship SFRH/BD/137668/2018

Halochromic properties of a 5-aminoimidazole-4-carboxamidrazone and its application to wool

This work was funded by European Regional Development Fund through the Operational Competitiveness Program and the National Foundation for Science and Technology of Portugal (FCT) under the projects UID/CTM/00264/2021, UID/QUI/00686/2020, MEDCOR PTDC/CTM-TEX/1213/2020 and Ph.D. scholarship SFRH/BD/137668/201

Hydroxybenzoic acid derivatives as dual-target ligands: mitochondriotropic antioxidants and cholinesterase inhibitors

Alzheimer's disease (AD) is a multifactorial age-related disease associated with oxidative stress (OS) and impaired cholinergic transmission. Accordingly, targeting mitochondrial OS and restoring cholinergic transmission can be an effective therapeutic strategy toward AD. Herein, we report for the first time dual-target hydroxybenzoic acid (HBAc) derivatives acting as mitochondriotropic antioxidants and cholinesterase (ChE) inhibitors. The studies were performed with two mitochondriotropic antioxidants AntiOxBEN1 (catechol derivative), and AntiOxBEN2 (pyrogallol derivative) and compounds 15–18, which have longer spacers. Compounds AntiOxBEN1 and 15, with a shorter carbon chain spacer (six- and eight-carbon) were shown to be potent antioxidants and BChE inhibitors (IC50 = 85 ± 5 and 106 ± 5 nM, respectively), while compounds 17 and 18 with a 10-carbon chain were more effective AChE inhibitors (IC50 = 7.7 ± 0.4 and 7.2 ± 0.5 μM, respectively). Interestingly, molecular modeling data pointed toward bifunctional ChEs inhibitors. The most promising ChE inhibitors acted by a non-competitive mechanism. In general, with exception of compounds 15 and 17, no cytotoxic effects were observed in differentiated human neuroblastoma (SH-SY5Y) and human hepatocarcinoma (HepG2) cells, while Aβ-induced cytotoxicity was significantly prevented by the new dual-target HBAc derivatives. Overall, due to its BChE selectivity, favorable toxicological profile, neuroprotective activity and drug-like properties, which suggested blood-brain barrier (BBB) permeability, the mitochondriotropic antioxidant AntiOxBEN1 is considered a valid lead candidate for the development of dual acting drugs for AD and other mitochondrial OS-related diseases.This work was funded by FEDER funds through the Operational Programme Competitiveness Factors-COMPETE and national funds by FCT – Foundation for Science and Technology under research grants (QUI/UI0081/2013, NORTE-01-0145-FEDER-000028 and PTDC/DTP-FTO/2433/2014, POCI-01-0145-FEDER-016659, POCI-01-0145-FEDER-007440. CO (SFRH/BD/88773/2012), FC (SFRH/BPD/74491/2010), JT (PTDC/DTP-FTO/2433/2014 and NORTE-01-0145-FEDER000028) RA (PTDC/DTP-FTO/2433/2014) grants are supported by FCT, POPH, and QREN. The authors also thank the COST action CA15135 for supportS

P-glycoprotein activation by 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5) in rat distal ileum: ex vivo and in vivo studies

In vitro studies showed that 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5) increases P-glycoprotein (P-gp) expression and activity in Caco-2 cells, preventing xenobiotic toxicity. The present study aimed at investigating TX5 effects on P-gp expression/activity using Wistar Han rats: a) in vivo, evaluating intestinal P-gp activity; b) ex vivo, evaluating P-gp expression in ileum brush border membranes (BBM) and P-gp activity in everted intestinal sacs; c) ex vivo, evaluating P-gp activity in everted intestinal sacs of the distal and proximal ileum. TX5 (30 mg/kg, b.w.), gavage, activated P-gp in vivo, given the significant decrease in the AUC of digoxin (0.25 mg/kg, b.w.). The efflux of rhodamine 123 (300 μM), a P-gp fluorescent substrate, significantly increased in TX5-treated everted sacs from the distal portion of the rat ileum, when P-gp activity was evaluated in the presence of TX5 (20 μM), an effect abolished by the P-gp inhibitor verapamil (100 μM). No increases on P-gp expression or activity were found in TX5-treated BBM of the distal ileum and everted distal sacs, respectively, 24 h after TX5 (10 mg/kg, b.w.) administration. In vivo, no differences were found on digoxin portal concentration between control (digoxin 0.025 mg/kg, b.w., intraduodenal) and TX5-treated (digoxin+TX5 20 μM, intraduodenal) rats. The observed discrepancies in digoxin results can be related to differences in TX5 dose administered and used methodologies. Thus, the results show that TX5 activates P-gp at the distal portion of the rat ileum, and, at the higher dose tested (30 mg/kg, b.w.), seems to modulate in vivo the AUC of P-gp substrates.Fil: Rocha-Pereira, Carolina. Universidad de Porto; PortugalFil: Ghanem, Carolina Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; ArgentinaFil: Silva, Renata. Universidad de Porto; PortugalFil: Casanova, Alfredo G.. Universidad de Salamanca; EspañaFil: Duarte Araújo, Margarida. Universidad de Porto; PortugalFil: Gonçalves Monteiro, Salomé. Universidad de Porto; PortugalFil: Sousa, Emília. Universidad de Porto; PortugalFil: Bastos, Maria de Lourdes. Universidad de Porto; PortugalFil: Remião, Fernando. Universidad de Porto; Portuga