Publications by authors named "Katayoun Derakhchan"

Article Synopsis
  • Fabry disease (FD) is a genetic disorder caused by mutations in the GLA gene, leading to the accumulation of harmful substances in cells and resulting in various health issues, including pain and severe complications in organs like the heart and kidneys.
  • Current treatments can help preserve kidney function but are less effective for heart problems, highlighting the need for better research models to test new drug therapies.
  • Two mouse models (GlaKO and G3Stg/GlaKO) have been developed to study FD, with the latter demonstrating more severe tissue and cardiac issues, and research aims to evaluate cardiac health using advanced imaging techniques.
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Mucopolysaccharidosis II (MPS II) is a rare lysosomal storage disease characterized by deficient activity of iduronate-2-sulfatase (I2S), leading to pathological accumulation of glycosaminoglycans (GAGs) in tissues. We used iduronate-2-sulfatase knockout ( KO) mice to investigate if liver-directed recombinant adeno-associated virus vectors (rAAV8-LSP-h) encoding human I2S (hI2S) could cross-correct I2S deficiency in KO mouse tissues, and we then assessed the translation of mouse data to non-human primates (NHPs). Treated mice showed sustained hepatic hI2S production, accompanied by normalized GAG levels in somatic tissues (including critical tissues such as heart and lung), indicating systemic cross-correction from liver-secreted hI2S.

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Prokinetic agents, specifically 5-hydroxytryptamine type 4 (5-HT 4 ) receptor agonists, have been shown to provide relief in chronic idiopathic constipation (CIC). The first-generation 5-HT 4 agonists were initially withdrawn from use owing to associations with serious cardiovascular (CV) events. This review summarizes CV safety data for prucalopride, a high-affinity 5-HT 4 agonist approved in the United States in 2018 for adults with CIC.

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Background: Prucalopride is a selective serotonin type 4 (5-HT) receptor agonist indicated for treatment of chronic idiopathic constipation (CIC) in adults (2 mg orally, daily). 5-HT receptors are present in the central nervous system; therefore, non-clinical and clinical assessments were performed to evaluate the tissue distribution and abuse potential of prucalopride.

Methods: In vitro receptor-ligand binding studies were performed to assess the affinity of prucalopride (≤1 mM) for peptide receptors, ion channels, monoamine neurotransmitters and 5-HT receptors.

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Background: Myostatin antagonists are being developed as therapies for Duchenne muscular dystrophy due to their strong hypertrophic effects on skeletal muscle. Engineered follistatin has the potential to combine the hypertrophy of myostatin antagonism with the anti-inflammatory and anti-fibrotic effects of activin A antagonism.

Methods: Engineered follistatin was administered to C57BL/6 mice for 4 weeks, and muscle mass and myofiber size was measured.

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The human cytomegalovirus (CMV) UL97 kinase inhibitor maribavir is in Phase III clinical trials as antiviral therapy, including use for infections refractory or resistant to standard therapy. To assess its activity in combination with approved and experimental CMV antivirals, and with the mTor inhibitor rapamycin (sirolimus), drug effects were tested by in vitro checkerboard assays and the data were analyzed using a three dimensional model based on an independent effects definition of additive interactions. Baseline virus and representative drug-resistant mutants were tested.

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Article Synopsis
  • Patients with chronic constipation can benefit from 5-HT receptor agonists, but earlier versions like cisapride and tegaserod were taken off the market due to cardiovascular issues that stemmed from their lack of selectivity.
  • This study investigates the cardiovascular safety of prucalopride, a new selective 5-HT receptor agonist, through various in vitro and in vivo experiments using animal models and human tissues.
  • Findings indicate that prucalopride shows no significant cardiovascular effects at high doses, suggesting it could be a safer alternative for treating chronic constipation without the heart-related risks seen in earlier drugs.
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The optimization of a series of aminooxazoline xanthene inhibitors of β-site amyloid precursor protein cleaving enzyme 1 (BACE1) is described. An early lead compound showed robust Aβ lowering activity in a rat pharmacodynamic model, but advancement was precluded by a low therapeutic window to QTc prolongation in cardiovascular models consistent with in vitro activity on the hERG ion channel. While the introduction of polar groups was effective in reducing hERG binding affinity, this came at the expense of higher than desired Pgp-mediated efflux.

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We have previously shown that the aminooxazoline xanthene scaffold can generate potent and orally efficacious BACE1 inhibitors although certain of these compounds exhibited potential hERG liabilities. In this article, we describe 4-aza substitution on the xanthene core as a means to increase BACE1 potency while reducing hERG binding affinity. Further optimization of the P3 and P2' side chains resulted in the identification of 42 (AMG-8718), a compound with a balanced profile of BACE1 potency, hERG binding affinity, and Pgp recognition.

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Introduction: Cardiac arrhythmia findings can be a challenge to interpret and difficult to attribute to background incidence or test article treatment. Thus, there is a growing need to better understand arrhythmia incidence in the experimental animal models used to assess the cardiovascular safety of new drugs. Currently, there is little information on the frequency of spontaneous cardiac arrhythmias in the cynomolgus monkey.

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Ranolazine is a novel anti-ischemic drug that prolongs the QT interval. To evaluate the potential mechanisms and consequences, we studied: (i) Ranolazine's effects on HERG and IsK currents in Xenopus oocytes with two-electrode voltage clamp; (ii) effects of ranolazine, compared to d-sotalol, on effective refractory period (ERP), QT interval and ventricular rhythm in a dog model of acquired long QT syndrome; and (iii) effects on selected native currents in canine atrial myocytes with whole-cell patch-clamp technique. Ranolazine inhibited HERG and IsK currents with different potencies.

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Atrial fibrillation (AF) is the most common cardiac arrhythmia requiring medical therapy, and present treatment modalities are inadequate. Over the past few years, we have learned a great deal about the phenomenon of electrical remodeling, by which rapid atrial activation leads to changes in atrial electrical properties that promote AF initiation and maintenance. This knowledge opens up the possibility that electrical remodeling may itself be a novel therapeutic target in AF.

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Background: Coronary artery disease is a significant risk factor for atrial fibrillation (AF), but the basis for this association is incompletely understood. The present study evaluated the hypothesis that atrial ischemia can create a substrate for AF maintenance.

Methods And Results: Atrial ischemia was induced by occlusion of an atrial arterial branch that did not provide blood flow to the ventricles.

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