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  1. 1

    8-(3-phenylpropyl)-1,3,7-triethylxanthine is a synthetic caffeine substitute with stronger metabolic modulator activity

    Publication
    by Carrageta, David F
    Other Authors: Dias, Tânia R.; Jarak, Ivana; Alves, Marco G; Oliveira, P.F.; Walt, Mietha Van Der et al.
    Origin: uBibliorum
    Caffeine is one of the most worldwide consumed methylxanthines. It is well-known for its thermogenic and cell metabolism modulating effects. Based on methylxanthines' chemical structure, 8-(3-phenylpropyl)-1,3,7-triethylxanthine (PTX) is a novel adenosine antagonist with higher receptor affinity than caffeine. Therefore, we hypothesized that PTX metabolic effects could be stronger than those of caffeine. For that purpose, murine 3T3-L1 cells were cultured in the presence of increasing doses of PTX or caffeine (0.1, 1, 10 and 100 μM) for 24 h. Cytotoxicity was evaluated by reduction of tetrazolium salt (MTT) and lactate dehydrogenase (LDH) release. Cell metabolites released to the culture medium were identified and quantified by proton nuclear magnetic resonance (1H NMR). Cellular oxidative profile was also evaluated. Our results showed that PTX displayed no signs of cytotoxicity at all studied concentrations. When compared with caffeine, PTX increased glucose, pyruvate, and glutamine consumption, as well as lactate, alanine, and acetate production. Additionally, PTX decreased protein oxidation, thus protecting against oxidative stress-induced damage. These results illustrate that PTX is a stronger and less cytotoxic caffeine substitute with potential applications as metabolic modulator and a good candidate for novel drug design.
    2018 article Portugal open access
  2. 2

    Ductular reaction, cytokeratin 7 positivity, and gamma-glutamyl transferase in multistage hepatocarcinogenesis in rats

    Publication
    by Moreira, Andrea Janz
    Other Authors: Rodrigues, Graziella Ramos; Bona, Silvia; Fratta, Leila Xavier Sinigaglia; Weber, Giovana Regina; Picada, Jaqueline Nascimento et al.
    Origin: uBibliorum
    Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and is characterized by multistage formation. The presence of ductular reaction, cytokeratin 7 positivity (PCK7), and increased levels of gamma glutamyltransferase (γGT) has been observed during liver carcinogenesis and contribute to tumor progression. Our goal was to evaluate the ductular reaction in multistage carcinogenesis and to correlate PCK7 and γGT levels with tumor incidence, histological characteristics, liver DNA damage index, and the expression of oxidative stress proteins. HCC was induced in 24 male Wistar rats weighing 145-150 g by chronic and intermittent exposure to 50 or 100 mg/kg diethylnitrosamine (DEN). Six control animals received only vehicle. Blood was collected to determine hepatic enzyme levels. Animals were divided into three groups: control (CO), precancerous lesions (PL), and advanced HCC. Liver samples were obtained for immunohistochemical analyses and the measurement of protein expression. Statistical analyses included Tukey's test and Pearson's correlation analyses. We observed an extensive ductular reaction in advanced HCC and a strong correlation between PCK7 and levels of γGT and the poor prognosis and aggressiveness of HCC. The extent of PCK7 and high γGT levels were associated with overexpression of inducible nitric oxide synthase (iNOS) and heat shock factor protein 1 (HSF-1). However, PCK7 and γGT levels were negatively correlated with protein expression of nuclear factor erythroid 2-related factor 2 (NRF2) and inducible heat shock protein 70 (iHSP70). These findings suggest that ductular reaction is involved in the progression of multistage hepatocarcinogenesis.
    2016 article Portugal open access
  3. 3

    The Action of Polyphenols in Diabetes Mellitus and Alzheimer's Disease: A Common Agent for Overlapping Pathologies

    Publication
    by Silveira, Ana C.
    Other Authors: Dias, Jane; Santos, Vanessa M.; Oliveira, P.F.; Alves, Marco G; Rato, Luís et al.
    Origin: uBibliorum
    Diabetes Mellitus (DM) and Alzheimer's disease (AD) are two prevalent diseases in modern societies, which are caused mainly by current lifestyle, aging and genetic alterations. It has already been demonstrated that these two diseases are associated, since individuals suffering from DM are prone to develop AD. Conversely, it is also known that individuals with AD are more susceptible to DM, namely type 2 diabetes (T2DM). Therefore, these two pathologies, although completely different in terms of symptomatology, end up sharing several mechanisms at the molecular level, with the most obvious being the increase of oxidative stress and inflammation. Polyphenols are natural compounds widely spread in fruits and vegetables whose dietary intake has been considered inversely proportional to the incidence of DM and AD. So, it is believed that this group of phytochemicals may have preventive and therapeutic potential, not only by reducing the risk and delaying the development of these pathologies, but also by improving brain's metabolic profile and cognitive function. The aim of this review is to understand the extent to which DM and AD are related pathologies, the degree of similarity and the relationship between them, to detail the molecular mechanisms by which polyphenols may exert a protective effect, such as antioxidant and anti-inflammatory effects, and highlight possible advantages of their use as common preventive and therapeutic alternatives.
    2019 article Portugal open access
  4. 4

    Current progress on microRNAs-based therapeutics in neurodegenerative diseases

    Publication
    by Pereira, Patrícia
    Other Authors: Queiroz, João; Figueiras, Ana; Sousa, Fani
    Origin: uBibliorum
    MicroRNAs (miRNAs)-based therapy has recently emerged as a promising strategy in the treatments of neurodegenerative diseases. Thus, in this review, the most recent and important challenges and advances on the development of miRNA therapeutics for brain targeting are discussed. In particular, this review highlights current knowledge and progress in the field of manufacturing, recovery, isolation, purification, and analysis of these therapeutic oligonucleotides. Finally, the available miRNA delivery systems are reviewed and an analysis is presented in what concerns to the current challenges that have to be addressed to ensure their specificity and efficacy. Overall, it is intended to provide a perspective on the future of miRNA-based therapeutics, focusing the biotechnological approach to obtain miRNAs. WIREs RNA 2017, 8:e1409. doi: 10.1002/wrna.1409 For further resources related to this article, please visit the WIREs website.
    2017 article Portugal restricted access
  5. 5

    Development and application of an ex vivo fosphenytoin nasal bioconversion/permeability evaluation method

    Publication
    by Viegas, Daniel Antunes
    Other Authors: Rodrigues, Márcio; Francisco, Joana; Falcão, Amílcar; Alves, Gilberto; Santos, Adriana O.
    Origin: uBibliorum
    There is an increasing interest in the intranasal delivery of central nervous system-active drugs due to the existence of a direct nose-to-brain connection. However, poor solubility limits the amount of drug that can be administered within an aqueous solution. In the present work, the objectives were to develop an ex vivo bioconversion/permeability evaluation method and to study the ex vivo bioconversion of the hydrophilic phosphate ester prodrug fosphenytoin (FOS) to the active drug phenytoin (PHT) and their comparative nasal permeation. Bioconversion/permeability studies were performed in excised porcine nasal mucosa mounted in Ussing chambers. The physical integrity of the tissues was evaluated by measurement of the transepithelial electrical resistance (TEER). The simultaneous quantitative assay of FOS, PHT and its major metabolite, 5-(4-hydroxyphenyl)-5-phenylhydantoin (HPPH) was developed and validated according to international guidelines using a liquid chromatography analytical method. The FOS bioconversion rate and PHT and FOS apparent permeability coefficients (Papp) were determined at different time points. FOS bioconversion was also qualitatively investigated in human nasal mucus. The developed liquid chromatography method combines a fast and inexpensive sample preparation with inactivation of the enzymatic metabolism of the prodrug during sample manipulation and storage. It was linear, precise, accurate, and presented a high analyte recovery. FOS was converted ex vivo to PHT but the metabolite HPPH was not detected. The bioconversion rate increased with FOS concentration and with time, which suggests a diffusion-limited process. FOS was also converted to its active drug by human nasal mucus. A novel mathematical data analysis method was developed to reduce the bias introduced by variable mucosal TEER in the permeability results. At comparable FOS and PHT concentrations the ln(Papp(PHT)) of both compounds showed little difference, which indicates that the use of a hydrophilic and charged prodrug did not hinder overall drug permeation. At the highest tested FOS concentration it was possible to quantify FOS in the receiver chambers, meaning that at a sufficiently high concentration the FOS permeation rate overcame its bioconversion rate. The ln(Papp(PHT)) tended to similar equilibrium values as the assay progressed, but with higher FOS concentrations that equilibrium was attained faster. Acidic pH reduced the permeability of both PHT and FOS. The developed bioconversion/permeability evaluation method will constitute an important tool to select the most promising formulations before proceeding to in vivo studies. Importantly, it allowed the demonstration of phosphatase activity and FOS bioconversion in nasal mucosa, as well as the prodrug's nasal permeation potential. Furthermore, this study demonstrates the possibility of formulating phosphate prodrugs of poorly soluble central nervous system-active drugs as a strategy to increase the solubilized drug doses administered through the nasal route.
    2016 article Portugal open access
  6. 6

    In Vivo bone tissue induction by freeze-dried collagen-nanohydroxyapatite matrix loaded with BMP2/NS1 mRNAs lipopolyplexes

    Publication
    by Wang, Pinpin
    Other Authors: Perche, Federico; Midoux, Patrick; Cabral, Cátia S. D.; Malard, Virginie; Correia, I.J. et al.
    Origin: uBibliorum
    Messenger RNA (mRNA) activated matrices (RAMs) are interesting to orchestrate tissue and organ regeneration due to the in-situ and sustained production of functional proteins. However, the immunogenicity of in vitro transcribed mRNA and the paucity of proper in vivo mRNA delivery vector need to be overcome to exert the therapeutic potential of RAM. We developed a dual mRNAs system for in vitro osteogenesis by co-delivering NS1 mRNA with BMP2 mRNA to inhibit RNA sensors and enhance BMP-2 expression. Next, we evaluated a lipopolyplex (LPR) formulation platform for in vivo mRNA delivery and adapted the LPRs for RAM preparation. The LPR formulated BMP2/NS1 mRNAs were incorporated into an optimized collagen-nanohydroxyapatite scaffold and freeze-dried to prepare ready-to-use RAMs. The loaded BMP2/NS1 mRNAs lipopolyplexes maintained their spherical morphology in the RAM, thanks to the core-shell structure of LPR. The mRNAs release from RAMs lasted for 16 days resulting in an enhanced prolonged transgene expression period compared to direct cell transfection. Once subcutaneously implanted in mice, the BMP2/NS1 mRNAs LPRs containing RAMs (RAM-BMP2/NS1) induced significant new bone tissue than those without NS1 mRNA, eight weeks post implantation. Overall, our results demonstrate that the BMP2/NS1 dual mRNAs system is suitable for osteogenic engagement, and the freeze-dried RAM-BMP2/NS1 could be promising off-the-shelf products for clinical orthopedic practice.
    2021 article Portugal open access
  7. 7

    Nanosystems in nose-to-brain drug delivery: a review of non-clinical brain targeting studies

    Publication
    by Pires, Patrícia C.
    Other Authors: Santos, Adriana O.
    Origin: uBibliorum
    The treatment of neurodegenerative and psychiatric disorders remains a challenge in medical research. Several strategies have been developed over the years, either to overcome the blood-brain barrier or to achieve a safer or faster brain delivery, one of them being intranasal (IN) administration. The possibility of direct nose-to-brain transport offers enhanced targeting and reduced systemic side effects. Nevertheless, labile, low soluble, low permeant and/or less potent drugs might need a formulation other than the common solutions or suspensions. For that, the formulation of nanosystems is considered to be a promising approach, since it can protect drugs from chemical and/or metabolic degradation, enhance their solubility, or offer transport through biological membranes. However, the understanding of the factors promoting efficient brain targeting when using nanosystems through the nasal route is currently patchy and incomplete. The main purpose of the present review was to evaluate the association between brain delivery efficacy (in terms of brain targeting, brain bioavailability and time to reach the brain) and nanosystem type. For that, we performed a systematic bibliographic search and analysis. Furthermore, study designs, nanosystem properties, and reporting quality were also analyzed and discussed. It was found a high heterogeneity in how pre-clinical brain targeting studies have been conducted, analyzed and reported in scientific literature, which surely originates a significant degree of bias and data dispersion. This review attempts to provide some systematization recommendations, which may be useful for researchers entering the field, and assist in increasing the uniformity of future reports. The analysis of literature data confirmed that there is evidence of the advantage of the IN route (when compared to the intravenous route) and in using carrier nanosystems (when compared to IN solutions) for brain delivery of a large set of drugs. Among the most represented nanosystem classes, microemulsions had some of the lowest pharmacokinetic ratios values, while polymeric micelles had some of the best. Nevertheless, brain targeting efficacy comparisons between nanosystem groups had little statistical significance, and the superiority of the polymeric micelles group disappeared when nanosystems were compared to the respective IN drug solutions. In fact, some drugs reached the brain so efficiently, even as drug solutions, that further benefit from formulating them into nanosystems became less evident.
    2018 article Portugal open access
  8. 8

    Mitochondrial Gene Therapy: Advances in Mitochondrial Gene Cloning, Plasmid Production, and Nanosystems Targeted to Mitochondria

    Publication
    by Coutinho, Eduarda
    Other Authors: Batista, Cátia; Sousa, Fani; Queiroz, João; Costa, Diana
    Origin: uBibliorum
    Mitochondrial gene therapy seems to be a valuable and promising strategy to treat mitochondrial disorders. The use of a therapeutic vector based on mitochondrial DNA, along with its affinity to the site of mitochondria, can be considered a powerful tool in the reestablishment of normal mitochondrial function. In line with this and for the first time, we successfully cloned the mitochondrial gene ND1 that was stably maintained in multicopy pCAG-GFP plasmid, which is used to transform E. coli. This mitochondrial-gene-based plasmid was encapsulated into nanoparticles. Furthermore, the functionalization of nanoparticles with polymers, such as cellulose or gelatin, enhances their overall properties and performance for gene therapy. The fluorescence arising from rhodamine nanoparticles in mitochondria and a fluorescence microscopy study show pCAG-GFP-ND1-based nanoparticles' cell internalization and mitochondria targeting. The quantification of GFP expression strongly supports this finding. This work highlights the viability of gene therapy based on mitochondrial DNA instigating further in vitro research and clinical translation.
    2017 article Portugal restricted access
  9. 9

    Fish as bags of macro and micronutrients: factors that influence fish excretion and body stoichiometry

    Publication
    by Cunha, Priscila de Oliveira
    Origin: Oasisbr
    A excreção de nutrientes e estequiometria corporal de consumidores podem ser influenciadas por vários fatores. Neste trabalho, testamos como 12 espécies de peixes de um córrego tiveram suas taxas de excreção de nutrientes afetadas pelo seu tamanho corporal, temperatura, estequiometria corporal e dieta (grupos alimentares como proxy). Nós aprofundamos a investigação sobre a magnitude do efeito da temperatura sobre as taxas de excreção de peixes de água doce através de uma meta-análise com 15 estudos e 40 tamanhos de efeito. Por fim, medimos o conteúdo corporal de 19 peixes para os elementos cálcio (Ca), fósforo (P), sódio (Na), potássio (K), enxofre (S), magnésio (Mg), manganês (Mn) e zinco (Zn). Testamos como a estequiometria corporal foi influenciada pelo habitat das espécies, suas guildas tróficas e ordens taxonômicas, e cada par de elementos foi testado para correlações. Nossos resultados mostram que o tamanho corporal é o principal fator determinando as taxas de excreção de nitrogênio (N) e fósforo (P) e, contrário às expectativas, a temperatura, estequiometria corporal e dieta não foram estatisticamente significativos no nosso estudo. Entretanto, experimentos futuros devem tentar incluir medidas de ingestão e egestão para aumentar a compreensão do efeito da dieta e estequiometria corporal nas taxas de excreção. Através da meta-análise, vimos que aumentos na temperatura levam a aumentos nas taxas de excreção, mas a magnitude do efeito é extremamente variável entre estudos. O tempo de aclimatização e status alimentar respondem juntos por 22% da variação, no entanto a maior parte desta permanece inexplicada e é muito provavelmente relacionada a identidade das espécies e suas características fisiológicas. São necessários mais experimentos usando métodos padronizados para explicar melhor a influência da temperatura na excreção de nutrientes. Finalmente, vimos que elementos com funções similares são correlacionados, especialmente cálcio e fósforo devido ao seu papel na formação dos ossos. Peixes tropicais apresentaram maior variação em sua composição corporal, o que pode estar relacionado com um nicho estequiométrico mais especializado ou com um maior tamanho amostral (12 espécies tropicais versus 7 espécies temperadas), e foram basicamente direcionadas por diferenças no conteúdo de Ca e P. A composição corporal dos peixes diferiu de acordo com as ordens taxonômicas, ressaltando a influencia da filogenia. A estequiometria corporal dos peixes também variou entre guildas tróficas, mas devido à presença de peixes com armadura óssea.
    2023 doctoral thesis Brazil open access
  10. 10

    A unidade metafísica do ser e a relação entre os humanos e os demais animais no pensamento de Schopenhauer

    Publication
    by Franco, Eduardo Ferraz
    Origin: Oasisbr
    The finding that the world known by the human cognitive apparatus leads Schopenhauer to unpower and equip the scope of intelligence and reason. If by these pathways the knowledge of the thing-in-itself is impossible, Schopenhauer finds it in the intimate feeling of the will. The intimate feeling of the essence of the self is expanded to the world that can only be a metaphysical unity, but it appears as self discord, imperfection. It is the possibility of visualizing the metaphysical unity of Being which enables the philosopher to extend the scope of consideration of human good actions to the animals.