Interplay between Pharmacokinetics and Pharmacogenomics

Pharmacogenomics represents an attempt to optimize the efficacy of drugs, minimize adverse drug reactions, and facilitate drug discovery, development, and approval. Understanding an individual’s genetic makeup can be the key to creating personalized drugs with greater efficacy and safety, as pharmacogenetic testing can be used to identify individuals who may be more susceptible to adverse drug reactions. Interindividual variability in the pharmacokinetics of many medicinal products is prone to interindividual variability. Pharmacogenomics should be considered one of the factors affecting the pharmacokinetics of a drug. When a polymorphism in a metabolizing enzyme and/or transporter causes a difference in exposure, it may alter efficacy or safety

PREDICTORS OF MAJOR BLEEDING AMONG ATRIAL FIBRILLATION PATIENTS ON WARFARIN

Objective: Bleeding is the most serious complication associated with anticoagulation therapy. The purpose of this study was to estimate the frequency of major bleeding related to warfarin and to identify its predictors in patients with atrial fibrillation (AF). Methods: Patients with AF treated with warfarin at Penang General Hospital in Malaysia were identified according to the international classification of disease, Ninth Revision, Clinical Modification (ICD-9). The medical reports of 1611 patients were reviewed, bleeding events were set as primary end point which were identified in 313 patients. Demographic and clinical data were retrieved and warfarin therapy-related parameters including dose, therapy duration, and prothrombin time-international normalized ratio (PT-INR) were recorded and analyzed using descriptive statistics. Results: Of the 313 patients, 28 patients with major bleeding events were identified. Gastrointestinal bleeding was the major type of bleeding, which accounts for 68% (n = 17) of the cases. The frequency of major bleeding events among all AF patients was 1.7%. High PT-INR value was found in 96.3% (n = 28) of the patients, thereby making it the primary predictor of bleeding events. Other predictors including, advanced age, other comorbidities such as hypertension and multiple anticoagulation therapy were also observed to be significant. Conclusion: Lower doses of warfarin are recommended to achieve target PT-INR range similar to that reported previously for Asian populations. A regular clinical review for bleeding predictors is essential for maximizing the time spent by the patient taking warfarin in the optimal therapeutic range and for making recommended therapy adjustment

Inhibitor and substrate binding induced stability of HIV-1 protease against sequential dissociation and unfolding revealed by high pressure spectroscopy and kinetics

High-pressure methods have become an interesting tool of investigation of structural stability of proteins. They are used to study protein unfolding, but dissociation of oligomeric proteins can be addressed this way, too. HIV-1 protease, although an interesting object of biophysical experiments, has not been studied at high pressure yet. In this study HIV-1 protease is investigated by high pressure (up to 600 MPa) fluorescence spectroscopy of either the inherent tryptophan residues or external 8-anilino-1-naphtalenesulfonic acid at 25°C. A fast concentration-dependent structural transition is detected that corresponds to the dimer-monomer equilibrium. This transition is followed by a slow concentration independent transition that can be assigned to the monomer unfolding. In the presence of a tight-binding inhibitor none of these transitions are observed, which confirms the stabilizing effect of inhibitor. High-pressure enzyme kinetics (up to 350 MPa) also reveals the stabilizing effect of substrate. Unfolding of the protease can thus proceed only from the monomeric state after dimer dissociation and is unfavourable at atmospheric pressure. Dimer-destabilizing effect of high pressure is caused by negative volume change of dimer dissociation of -32.5 mL/mol. It helps us to determine the atmospheric pressure dimerization constant of 0.92 μM. High-pressure methods thus enable the investigation of structural phenomena that are difficult or impossible to measure at atmospheric pressure. © 2015 Ingr et al.INSERM; Grant Agency of the Czech Republic [P208-12-G016

Nouveaux aspects dans la double signalisation du "Brain-derived Neurotrophic Factor" : implications d'un déséquilibre dans les mécanismes de neuroprotection et neurotoxicité

Le « Brain-Derived Neurotrophic Factor » (BDNF) est la neurotrophine la plus abondante et la plus répandue dans le cerveau humain. De nombreuses études se sont intéressées à son rôle dans la survie neuronale, la croissance et la plasticité synaptique. La signalisation BDNF est dépendante de deux récepteurs, le récepteur tyrosine kinase (TrkB) et le récepteur neurotrophine p75 (p75NTR). Il est bien établi que le rôle trophique du BDNF est assuré via son récepteur de haute-affinité TrkB, alors que la forme précurseur proBDNF active p75NTR vers la voie d'apoptose. Cette double signalisation est physiologiquement contrôlée par un équilibre entre les différentes voies. Les résultats obtenus à partir des études cliniques et des modèles animaux suggèrent un rôle de la signalisation BDNF dans les tauopathies, caractérisées par l'existence de dépôts intracérébraux de protéine tau, une caractéristique commune à certaines maladies neurodégénératives, notamment la maladie d'Alzheimer (MA). Cependant, aucune investigation n'a été menée jusqu'à présent sur les modifications que pouvaient induire les tauopathies dans la signalisation BDNF et si une dérégulation de l'expression du BDNF pouvait affecter ses propres récepteurs TrkB et p75NTR.Dans ce travail de thèse, nous avons utilisé une lignée de poisson-zèbre transgénique portant la mutation humaine TAUP301L retrouvée notamment dans le démence fronto-temporale. Nous avons mesuré l'expression de BDNF et de ses deux récepteurs au niveau transcriptionnel et protéique. Nous n'avons observé aucune modification des taux d'expression de BDNF et de TrkB, en revanche, nous avons noté une augmentation significative de p75NTR. A l'aide de la même lignée transgénique, nous avons induit une baisse d'expression de BDNF via la micro-injection de morpholinos. De manière remarquable, la baisse d'expression de BDNF affecte de façon différentielle TrkB et p75NTR. En effet, nous avons observé une diminution de l'expression de TrkB et parallèlement une augmentation de p75NTR. De plus, la baisse d'expression de BDNF aggrave la neurotoxicité associée au développement de la tauopathie ce qui se traduit par une augmentation de la mort neuronale et de l'hyperphosphorylation de tau, cette dernière étant concommittante à une activation de la Glycogen Synthétase Kinase 3 beta (GSK3beta).Une diminution de l'effet neuroprotecteur de BDNF à travers un déséquilibre de ces récepteurs de signalisation a été également montré en étudiant le rôle de BDNF au cours du développement de la ligne latérale postérieure (PLL). Ce système est considéré comme un modèle d'étude particulièrement pertinent pour évaluer différents processus biologiques comme la migration cellulaire collective ou la régénération cellulaire. Nous avons détecté l'expression de BDNF dans plusieurs structures de la PLL. La diminution d'expression de BDNF conduit à un défaut de migration du primordium de la PLL, associé à une augmentation de la mort cellulaire. De plus, nous avons observé une réduction de la prolifération cellulaire et un défaut de repousse axonale du nerf, ce qui conduit à des anomalies de régénération à la fois du nerf de la PLL et des cellules ciliées. Nos résultats suggèrent que le BDNF joue un rôle essentiel au cours du développement de la PLL et démontrent la pertinence du système de la ligne latérale en tant que modèle d'étude des fonctions de BDNF.En conclusion, notre étude représente la première analyse du rôle in vivo de BDNF et de ses 2 récepteurs de signalisation. Nous avons ainsi montré les répercussions d'une dérégulation des voies de signalisation du BDNF. Un équilibre entre ces deux voies est essentiel pour le développement et la survie cellulaire, ce qui fait de BDNF non seulement une cible thérapeutique potentielle, mais également une neurotrophine clé pouvant activer plusieurs circuits de signalisation, potentialisant ainsi son rôle protecteur.Brain-derived neurotrophic factor (BDNF) is the most abundant secreted and widely distributed neurotrophin in human brain. It has been extensively studied for its role in neuronal survival, growth and synaptic plasticity. BDNF signaling mediated through tryosine receptor kinase B (TrkB) and p75NTR neurotrophin receptor (p75NTR). It is well established that BDNF beneficial actions are mediated by it is high-affinity TrkB, whereas pro-BDNF activates p75NTR towards apoptosis. This diverse dual signaling is normally under a tight balance regulation. Based on clinical and animal studies, it has been suggested that BDNF signaling is involved in tauopathy, which is a pathological hallmark in several neurodegenerative diseases, including Alzheimer's disease (AD). However, what changes tauopathy may induce on BDNF signaling, and whether BDNF deregulation could affect its two signaling receptors (TrkB, p75NTR), and eventually tauopathy pathogenesis, have not been investigated. In this study we used a transgenic zebrafish line for human Tau-P301L tauopathy, and measured transcriptional and protein levels of BDNF and of its two signaling receptors. We found no modification of BDNF and TrkB expression levels, but a significant up-regulation of p75NTR. We then used the same transgenic line to generate BDNF knockdown using morpholino microinjection technique. Interestingly, BDNF knockdown differentially affects TrkB and p75NTR; we observed a reduction of TrkB expression and an increase in p75NTR expression. In addition, BDNF knockdown aggravates tauopathy-associated toxicity; we found an increase in neuronal cell death and tau hyperphosphorylation, the latter was accompanied by an activation of tau glycogen synthase kinase 3beta (GSK3beta). Attenuation of BDNF neuroprotective effects through imbalance of its signaling receptors was further highlighted through studying BDNF role in the development of zebrafish posterior lateral line system (PLL). This system has recently emerged as a powerful tool to study several dynamic biological processes, including collective cell migration and nerve/hair cells regeneration. We detected BDNF expression in different PLL components. BDNF knockdown led to an impairment of the PLL primordium migration due to concomitant increase in cell death rate. In addition, reduced cell proliferation and defect in axonal re-growth were observed , which led to major defects of PLL nerve/hair cells regeneration, respectively. These findings suggest that BDNF has an essential role in PLL development, but more important they introduce PLL as research model to study BDNF functions. This is the first study to provide a detailed in vivo analysis of BDNF and its two signaling receptors. Our findings highlight several implications of BDNF signaling deregulation. Balanced signaling clearly has essential roles in survival and development, in addition to being a therapeutic target, BDNF can itself activate diverse molecular pathways, thus setting up a potential circuitry that could enhance its protective role

Impact, obstacles and boundaries of patient partnership: A qualitative interventional study in Lebanon.

The patient as partner approach is a modern ‎model of patient engagement that integrates the patients' knowledge and skills into managing their own health. This study aims to evaluate the benefits and barriers of patient partnership in a healthcare setting. It is a qualitative and interventional study that implemented a patient and family partnership committee (PFPC) at a Lebanese hospital during the COVID-19 pandemic. A purposeful guided approach was used for sampling, and data was collected by structured questionnaire ‎interviews. Seven PFPC team dynamics building blocks were generated: transparency, support, motivation, comfortable communication, mutual understanding, equity in positions and empowerment to participate. Both the patient partners (94%) and healthcare professionals (90%) were satisfied with the PFPC experience. The majority of the healthcare professionals (HP) reported a noticeable change in the quality improvement process (QIP) (89%) and approved to standardize the PFPC (93%). The patient partnership benefits were clear, and the PFPC was perceived positively by both patient partners (PP) and HP. PP experienced distress relief (37%), gained ideas (41%) and felt that their opinion was heard (27%) after PFPC participation. PP reported benefits to hospitalized patients, including respect and care (63%) and patient satisfaction (20%). The main challenges for PFPC implementation were time availability and conflicts. Lessons from patient partnership can be utilized to improve the patient care policies in the Lebanese healthcare system. Moreover, developing countries can benefit from the patient partnership approach in their healthcare settings

Comparative study on shear strength and life cycle assessment of reinforced concrete beams containing different types of fibers

A variety of fibers currently exists in the construction market; however, their effect on concrete performance, cost, and environment are not being evaluated systematically. This study investigates the influence of different fibers (polypropylene, glass, basalt, polyvinyl alcohol, and steel), having different aspect ratios, on shear strength of reinforced concrete beams designed without stirrups. A life cycle assessment for each fiber type highlighting the environmental emissions and production costs is performed. Test results showed that the shear strength increased by 38.6% with the use of polypropylene fibers possessing low aspect ratio of 42, while such increase was limited to 11.5% with the incorporation of basalt fibers possessing an aspect ratio of 700. The polyvinyl alcohol fibers exhibited the highest ductility and energy transfer in the post-peak region, while the load versus deflection curves sharply dropped for concrete containing steel fibers reflecting reduced adhesion with the cement paste. The life cycle assessment showed higher environmental impact varying from 4% to 9% due to fibers additions, together with increased cost ranging between 34% and 150%. When taking all factors into account (performance, cost, and environmental impact), the polyvinyl alcohol fibers were most efficient followed by the polypropylene ones

Neuroprotective brain-derived neurotrophic factor signaling in the TAU-P301L tauopathy zebrafish model

International audienceBrain-derived neurotrophic factor (BDNF) dysregulations contribute to the neurotoxicity in neurodegenerative pathologies and could be efficiently targeted by therapies. In Alzheimer's disease (AD), although the relationship between BDNF and amyloid load has been extensively studied, how Tau pathology affects BDNF signaling remains unclear. Using the TAU-P301L transgenic zebrafish line, we investigated how early Tau-induced neuro-toxicity modifies BDNF signaling. Alterations in BDNF expression levels were observed as early as 48 h post fertilization in TAU-P301L zebrafish embryos while TrkB receptor expression was not affected. Decreasing BDNF expression, using a knockdown strategy in wild-type embryos to mimic Tau-associated decrease, did not modify TrkB expression but promoted neurotoxicity as demonstrated by axonal outgrowth shortening and neuronal cell death. Moreover, the TrkB antagonist ANA-12 reduced the length of axonal projections. Rescue experiments with exogenous BDNF partially corrected neuronal alterations in TAU-P301L by counteracting primary axonal growth impairment but without effect on apoptosis. Importantly, the axonal rescue was proved functionally effective in a behavioral test, at a similar level as obtained with the GSK3β inhibitor LiCl, known to decrease TAU phos-phorylation. Finally, treatment with a TrkB agonist, 7,8-dihydroxyflavone, led to comparable results and allowed full rescue of locomotor response. We provided here strong evidence that Tau neurotoxicity provoked alterations in BDNF system and that BDNF pathway might represent an efficient therapeutic target

Exploring the Roles of Vitamins C and D and Etifoxine in Combination with Citalopram in Depression/Anxiety Model: A Focus on ICAM-1, SIRT1 and Nitric Oxide

The study of intercellular adhesion molecule-1 (ICAM-1) and SIRT1, a member of the sirtuin family with nitric oxide (NO), is emerging in depression and anxiety. As with all antidepressants, the efficacy is delayed and inconsistent. Ascorbic acid (AA) and vitamin D (D) showed antidepressant properties, while etifoxine (Etx), a GABAA agonist, alleviates anxiety symptoms. The present study aimed to investigate the potential augmentation of citalopram using AA, D and Etx and related the antidepressant effect to brain and serum ICAM-1, SIRT1 and NO in an animal model. BALB/c mice were divided into naive, control, citalopram, citalopram + etx, citalopram + AA, citalopram + D and citalopram + etx + AA + D for 7 days. On the 8th day, the mice were restrained for 8 h, followed by a forced swim test and marble burying test before scarification. Whole-brain and serum expression of ICAM-1, Sirt1 and NO were determined. Citalopram’s antidepressant and sedative effects were potentiated by ascorbic acid, vitamin D and etifoxine alone and in combination (p p p p < 0.05) versus naive. Both ICAM-1 and Sirt1 were modulated by antidepressants through a non-NO-dependent pathway. Serum NO expression was unrelated to serum ICAM-1 and Sirt1. Brain ICAM-1, Sirt1 and NO are implicated in depression and are modulated by antidepressants

Initial rate of substrate cleavage as a function of pressure related to the value for 10 MPa.

<p>Different symbols denote three experimental series. The solid curve shows the relative rate for the ideal case of pressure dependent <i>K</i>_<i>d</i> but pressure independent <i>K</i>_<i>m</i> and <i>k</i>_<i>cat</i>.</p

Time development of the tryptophan-fluorescence CSM.

<p>A. Time series for different pressures, each started with a new enzyme sample, concentration of 10 μM dimer. The individual curves are shifted up or down by artificially chosen constant for the sake of better orientation in the graph. B. Time series measured with the same sample of 2 μM concentration, pressure setting is facilitated by pressure jumps. The CSM scale is genuine for all the series.</p