Repurposing conventional antimycobacterial drugs using ionic liquids

Nontuberculous mycobacteria, namely the species belonging to the Mycobacterium avium complex, are highly infectious opportunistic pathogens, which incidence is increasing worldwide. Treating these infections is challenging, due to long duration, high toxicity, and low effectiveness of available drugs. It is therefore urgent to find new therapeutic strategies, including the repurposing of old drugs. Ionic liquids (ILs) are organic salts made by the combination of two molecules with opposite polarities, which are gaining attention in drug development. Combining the right ions, it is possible to create ILs that could avoid polymorphism and solubility issues presented by solid conventional drugs, improving their absorption and desired dissolution rate. Besides increasing the bioavailability, the main goals when formulating a new IL is keeping or improving the bioactivity and cytotoxicity properties of the parental drug(s). The aim of our work is to evaluate the ability of ILs based on conventional antimycobacterial drugs, like clofazimine, aminosalicylic acid, and fluoroquinolones, to inhibit the viability and growth of M. avium in axenic culture and inside macrophages.info:eu-repo/semantics/publishedVersio

Cinnamic acid conjugates in the rescuing and repurposing of classical antimalarial drugs

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).Cinnamic acids are compounds of natural origin that can be found in many different parts of a wide panoply of plants, where they play the most diverse biological roles, often in a conjugated form. For a long time, this has been driving Medicinal Chemists towards the investigation of the therapeutic potential of natural, semi-synthetic, or fully synthetic cinnamic acid conjugates. These efforts have been steadily disclosing promising drug leads, but a wide chemical space remains that deserves to be further explored. Amongst different reported approaches, the combination or conjugation of cinnamic acids with known drugs has been addressed in an attempt to produce either synergistic or multi-target action. In this connection, the present review will focus on efforts of the past decade regarding conjugation with cinnamic acids as a tool for the rescuing or the repurposing of classical antimalarial drugs, and also on future perspectives in this particular field of research.This research was funded by Fundação para a Ciência e Tecnologia (FCT), Portugal, grants UID/QUI/50006/2019, and PTDC/BTM-SAL/29786/2017.info:eu-repo/semantics/publishedVersio

Hereditary breast cancer and ancestry in the Madeira archipelago: An exploratory study

Access to genetic testing and counselling in remote areas such as the Madeira archipelago, in the Northern Atlantic Ocean, may be complex. Different counselling methods, including telegenetics, should be explored. In this study, we characterise the Hereditary Breast/Ovarian Cancer (HBOC) families with Madeira ancestry enrolled in our programme. Of a total of 3, 566 index patients tested between January 2000 and June 2018, 68 had Madeira ancestry and 22 were diagnosed with a pathogenic germline variant (PV). As in the whole group, BRCA2 PV were more frequent in Madeira patients (68.4%: c.9382C>T (26.3%), c.658_659del (21%), c.156_157insAlu (10.5%), c.793+1G>A (5.3%) and c.298A>T (5.3%). However, the most frequently diagnosed PV in Madeira patients was the BRCA1 c.3331_3334del (31.6%). BRCA1/2 detection rates were 27.9% and 10.5% for Madeira and the whole group, respectively. This study is the first characterisation of HBOC patients with Madeira ancestry. A distinct pattern of BRCA1/2 variants was observed, and the geographic clustering of BRCA1 c.3331_3334del variant may support the possibility of a founder mutation previously described in Northern Portugal. The high detection rate observed reinforces the need to reduce gaps in access to genetic testing in Madeira and other remote areas. According to current guidelines, timely identification of HBOC patients can contribute to their ongoing care and treatment

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Evolution of Antibacterial Drug Screening Methods: Current Prospects for Mycobacteria

The increasing resistance of infectious agents to available drugs urges the continuous and rapid development of new and more efficient treatment options. This process, in turn, requires accurate and high-throughput techniques for antimicrobials’ testing. Conventional methods of drug susceptibility testing (DST) are reliable and standardized by competent entities and have been thoroughly applied to a wide range of microorganisms. However, they require much manual work and time, especially in the case of slow-growing organisms, such as mycobacteria. Aiming at a better prediction of the clinical efficacy of new drugs, in vitro infection models have evolved to closely mimic the environment that microorganisms experience inside the host. Automated methods allow in vitro DST on a big scale, and they can integrate models that recreate the interactions that the bacteria establish with host cells in vivo. Nonetheless, they are expensive and require a high level of expertise, which makes them still not applicable to routine laboratory work. In this review, we discuss conventional DST methods and how they should be used as a first screen to select active compounds. We also highlight their limitations and how they can be overcome by more complex and sophisticated in vitro models that reflect the dynamics present in the host during infection. Special attention is given to mycobacteria, which are simultaneously difficult to treat and especially challenging to study in the context of DST

Reactivity of cationic α-diimine cyclopentadienyl nickel complexes towards AlEt₂Cl:synthesis, characterisation and ethylene polymerisation

The electronically saturated and air-stable complexes [Ni(η5-C5H5)(Mes-BIAN)][PF6] (1) and [Ni(η5-C5H5)(Mes-DAD)][PF6] (2) were found to behave as efficient catalyst precursors for the polymerisation of ethylene under mild reaction conditions (temperature and pressure), when activated with small excesses of AlEt2Cl (DEAC), and exhibiting activities in the range 4×104 to 22×104 g PE/(mol Ni·h·bar). Compound 2 was synthesised and fully characterised as reported hereby for the first time, and exhibits a catalytic activity of ca. 30×104 g PE/(mol Ni·h·bar) in the polymerisation of ethylene. The reactivity of these complexes towards DEAC was found to lead to the formation of diamagnetic cationic Ni(II) complexes (4 and 3, respectively) containing the same initial cation [Ni(η5-C5H5)(α-diimine)]+ and a [AlEtCl3]- anion, whereby α-diimine = BIAN (1 and 4) and DAD (2 and 3). In the corresponding reaction of complex [Ni(η5-C5H5)(Mes-BIAN)][PF6] (1), an unusual paramagnetic complex incorporating a cationic trinuclear α-diimine Ni cluster (5), containing five bridging Cl ligands and a [AlCl4]- anion, was also isolated and fully characterised, in which the cyclopentadienyl ligand was absent. The intermediates 3 and 5 also catalysed efficiently the polymerisation of ethylene when the DEAC co-catalyst was used in slight excess. The polyethylene produced (ca. 10×104 to 30×104 g PE/(mol Ni·h·bar), respectively) showed branching numbers ranging from 7 to 75 branches/1000 carbon atoms according to 1H NMR spectroscopy analysis. These findings are surprising given that the new 18-electron nickel precursors show remarkable properties towards ethylene polymerisation catalysis when activated with a small excess of aluminium activator under mild conditions, and also that some unusual intermediates responsible for the observed activity were isolated and characterised by X-ray crystallography

Ionic liquids on the rescuing of conventional antimycobacterial drugs

The incidence of infections by nontuberculous mycobacteria (NTM) is increasing worldwide, mainly those caused by Mycobacterium avium complex (MAC) species. NTM are opportunistic pathogens that infect immunocompromised patients, namely those infected with HIV, with cancer or who were subject to a transplant. NTM are highly infectious and cause persistent infections due to their ability to easily form aerosols, to settle as biofilms and to resist to harsh environments, like chlorinated water. In the host, mycobacteria proliferate inside phagocytic cells, such as macrophages. There, they multiply inside small vacuoles and control the intracellular vesicular trafficking inhibiting the phagosome-lysosome fusion, which allowsthem to escape the lysosomal acidic environment and to have access to nutrients. NTM infections manifest primarily as pulmonary diseases, but can also affect other regions of the body, like the central nervous system, and cause lymphadenitis, which is the most common NTM-associated disease in immunocompetent children. The treatment basis of slow-growing NTM, in which MAC is included, is a macrolide. Clarithromycin or azithromycin are the usual options. A regimen of monotherapy with macrolides is, however, very dangerous as it will often lead to drug resistance and consequent treatment failure. Thus, a three-drug macrolide-based regimen with ethambutol and a rifamycin, which usually lasts from 6 to 12 months, is the recommended treatment. The addition of a fourth drug to the regimen, like aminoglycosides or a fluoroquinolone, can beimportant in more severe cases and is essential in cases of macrolide-resistant MAC. A very long multi-drug regimen like this, results in several issues to the patients, which decreases the probability of treatment success. It is thus urgent to finda new strategy to treat mycobacterial infections, including the repurposing of old drugs. Ionic liquids (ILs) are organic saltsmade by the combination of two molecules with opposite polarities. Their remarkable physical and chemical properties contributed for their extensive use as green-solvents, improving the performance and safety of chemical procedures, as well as vehicles in sensors and drug delivery systems. Recently, ILs have gained much attention in the area of drug development as antimicrobial agents, since they have shown improved solubility and bioavailability when compared to clinically approved drugs. The right combination of cations and anions can provide innovative compounds that help combat resistance issues. The aimof our work is to evaluate the capacity of ILs based on conventional antimycobacterial drugs to inhibit the viability and growthof M. avium in axenic culture and inside bone marrow-derived macrophages (BMM). We are assessing if the activity and toxicity of these compounds are improved by being in the IL form instead of being administered individually or in combination. Our results show that ILs derived from each of two fluoroquinolones, ofloxacin or norfloxacin, and the antimycobacterial drugclofazimine cause a more significant decrease in the extracellular and intracellular mycobacterial viability than the fluoroquinolones administered individually. Moreover, the ILs are less toxic to the host cells than clofazimine. Another pairofILs, which combine one classical antimalarial drug, chloroquine or primaquine, with the anti-tuberculosis drug aminosalicylic acid, also shows promising results: the ILs are more active against M. avium growing inside BMM than the three parental drugs by themselves. Therefore, our data encourage us to continue combining conventional anti-NTM antibiotics with molecules active against other pathogens in an IL form as a way to enhance their activity, improve pharmacological issues and combat resistances. In the future, we aim to test these ILs in more complex in vitro models of infection, such as biofilms and in vitrogranulomas, taking advantage of fluorescent and bioluminescent reporter strains of M. avium, in order to better predict theirclinical outcome and reduce the use of animals in preliminary drug testing.info:eu-repo/semantics/publishedVersio

Improving the Antimycobacterial Drug Clofazimine through Formation of Organic Salts by Combination with Fluoroquinolones

This work reports the synthesis, structural and thermal analysis, and in vitro evaluation of the antimicrobial activity of two new organic salts (OSs) derived from the antimycobacterial drug clofazimine and the fluoroquinolones ofloxacin or norfloxacin. Organic salts derived from active pharmaceutical ingredients (API-OSs), as those herein disclosed, hold promise as cost-effective formulations with improved features over their parent drugs, thus enabling the mitigation of some of their shortcomings. For instance, in the specific case of clofazimine, its poor solubility severely limits its bioavailability. As compared to clofazimine, the clofazimine-derived OSs now reported have improved solubility and thermostability, without any major deleterious effects on the drug’s bioactivity profile