1,720,975 research outputs found
Myasthenia Gravis Treatment: From Old Drugs to Innovative Therapies with a Glimpse into the Future
Full text link: Myasthenia gravis (MG) is a rare autoimmune disease that causes debilitating muscle weakness due to impaired neuromuscular transmission. Since most (about 80-90%) MG patients present autoantibodies against the acetylcholine receptor, standard medical therapy consists of symptomatic treatment with acetylcholinesterase inhibitors (e.g., pyridostigmine). In addition, considering the autoimmune basis of MG, standard therapy includes immunomodulating agents, such as corticosteroids, azathioprine, cyclosporine A, and cyclophosphamide. New strategies have been proposed for the treatment of MG and include complement blockade (i.e., eculizumab, ravulizumab, and zilucoplan) and neonatal Fc receptor antagonism (i.e., efgartigimod and rozanolixizumab). The aim of this review is to provide a detailed overview of the pre- and post-marketing evidence on the five pharmacological treatments most recently approved for the treatment of MG, by identifying both preclinical and clinical studies registered in clinicaltrials.gov. A description of the molecules currently under evaluation for the treatment of MG is also provided
Pharmacological Therapies of Spinal Muscular Atrophy: A Narrative Review of Preclinical, Clinical-Experimental, and Real-World Evidence
No full text: Spinal muscular atrophy (SMA) is a rare neuromuscular disease, with an estimated incidence of about 1 in 10,000 live births. To date, three orphan drugs have been approved for the treatment of SMA: nusinersen, onasemnogene abeparvovec, and risdiplam. The aim of this narrative review was to provide an overview of the pre- and post-marketing evidence on the pharmacological treatments approved for the treatment of SMA by identifying preclinical and clinical studies registered in clinicaltrials.gov and in the EU PAS register from their inception until the 4 January 2023. The preclinical evidence on the drugs approved for SMA allowed a significant acceleration in the experimental phase of these drugs. However, since these drugs had been authorized through accelerated programs, the conduction of post-marketing studies was requested as a condition of their marketing approval to better understand their risk-benefit profiles in real-world settings. As of the 4 January 2023, a total of 69 post-marketing studies concerning the three orphan drugs approved for SMA were identified in clinicaltrials.gov (N = 65; 94.2%) and in the EU PAS register (N = 4; 5.8%). Currently, ongoing studies are primarily aimed at providing evidence concerning the risk-benefit profile of the three drugs in specific populations that were not included in the pivotal trials and to investigate the long-term safety and clinical benefits of these drugs. Real-world data sources collecting information regarding the natural history of the disease and post-marketing surveillance of the available therapies are increasingly becoming essential for generating real-world evidence on this rare disease and its orphan drugs
Preclinical study of the antimyotonic efficacy of safinamide in the myotonic mouse model
Full text linkMexiletine is the first choice drug in the treatment of non-dystrophic myotonias. However, 30% of patients experience little benefit from mexiletine due to poor tolerability, contraindications and limited efficacy likely based on pharmacogenetic profile. Safinamide inhibits neuronal voltage-gated sodium and calcium channels and shows anticonvulsant activity, in addition to a reversible monoamine oxidase-B inhibition. We evaluated the preclinical effects of safinamide in an animal model of Myotonia Congenita, the ADR (arrested development of righting response) mouse. In vitro studies were performed using the two intracellular microelectrodes technique in current clamp mode. We analyzed sarcolemma excitability in skeletal muscle fibers isolated from male and female ADR (adr/adr) and from Wild-Type (wt/wt) mice, before and after the application of safinamide and the reference compound mexiletine. In ADR mice, the maximum number of action potentials (N-spikes) elicited by a fixed current is higher with respect to that of WT mice. Myotonic muscles show an involuntary firing of action potential called after-discharges. A more potent activity of safinamide compared to mexiletine has been demonstrated in reducing N-spikes and the after-discharges in myotonic muscle fibers. The time of righting reflex (TRR) before and after administration of safinamide and mexiletine was evaluated in vivo in ADR mice. Safinamide was able to reduce the TRR in ADR mice to a greater extent than mexiletine. In conclusion, safinamide counteracted the abnormal muscle hyperexcitability in myotonic mice both in vitro and in vivo suggesting it as an effective drug to be indicated in Myotonia Congenita
Ion channels as biomarkers of altered myogenesis in myofiber precursors of Duchenne muscular dystrophy
Full text linkMyogenesis is essential for skeletal muscle formation, growth, and regeneration and can be altered in Duchenne muscular dystrophy (DMD), an X-linked disorder due to the absence of the cytoskeletal protein dystrophin. Ion channels play a pivotal role in muscle differentiation and interact with the dystrophin complex. To investigate ion channel involvement in myogenesis in dystrophic settings, we performed electrophysiological characterization of two immortalized mouse cell lines, wild-type (WT) H2K-2B4 and the dystrophic (DYS) H2K-SF1, and measured gene expression of differentiation markers and ion channels. Inward and outward currents/density increased as differentiation progressed in both WT and DYS cells. However, day-11 DYS cells showed higher (27%) inward current density with an increased expression ratio of Scn5a/Scn4a and decreased (48%) barium-sensitive outward current compared to WT. Furthermore, day-11 DYS cells showed more positive resting membrane potential (+10 mV) and lower membrane capacitance (50%) compared to WT. DYS cells also had reduced Myog and Myf5 expression at days 6 and 11. Overall, ion channel profile and myogenesis appeared altered in DYS cells. These results are a first step in validating ion channels as potential drug targets to ameliorate muscle degeneration in DMD settings and as differentiation biomarkers in innovative platforms.Ion channels have an active crosstalk with the dystrophin complex, which is disrupted in Duchenne muscular dystrophy, but little is known about their involvement in myogenesis, especially in dystrophic settings. We performed an electrophysiological characterization of wild-type and dystrophic myoblasts/myocytes to shed light on the relationship between dystrophin loss and ion channel activity during myogenesis with the final aim to identify new biomarkers and drug targets in regenerative medicine approaches. # imag
Determination of qPCR reference genes suitable for normalizing gene expression in a novel model of Duchenne muscular dystrophy, the D2-mdx mouse
Full text linkDuchenne muscular dystrophy (DMD) is a X-linked neuromuscular disorder arising from mutations in the dystrophin gene, leading to a progressive muscle wasting and disability. Currently there is no universal therapy, and there is thus a strong interest in preclinical studies for finding novel treatments. The most widely used and characterized mouse model for DMD is the C57BL/10ScSn-Dmdmdx/J (BL10-mdx), but this model exhibits mild pathology and does not replicate key features of human disease. The D2.B10-Dmdmdx/J (D2-mdx) mouse is a more recent model which seems to better mimics the complex human DMD phenotype. However, the D2-mdx mouse remains less extensively characterised than its BL10-mdx counterpart. Quantitative PCR analysis of gene expression is an important tool to monitor disease progression and evaluate therapeutic efficacy, but measurements must be normalised to stably expressed reference genes, which should ideally be determined and validated empirically. We examined gene expression in the gastrocnemius (GC), diaphragm (DIA) and heart in the D2-mdx mouse, the BL10-mdx mouse, and appropriate strain-matched wild-type controls (D2-wt and BL10-wt), from 4 to 52 weeks of age, using a large panel of candidate references (ACTB, AP3D1, CSNK2A2, GAPDH, HPRT1, PAK1IP1, RPL13A, SDHA, and in the heart, also HTATSF1 and HMBS). Data was analyzed using GeNorm, Bestkeeper, deltaCt and Normfinder algorithms to identify stable references under multiple possible scenarios. We show that CSNK2A2, AP3D1 and ACTB represent strong universal reference genes in both GC and DIA, regardless of age, muscle type, strain and genotype, while HTATSF1 and SDHA are optimal for the heart. GAPDH, HPRT1 and RPL13A were conversely revealed to be poor references, showing tissue-, age- or disease-specific changes in expression. Our results illustrate the importance of determining appropriate reference genes for specific comparative scenarios, but also reconfirm that universal panels can nevertheless be identified for normalising gene expression studies in even complex pathological states
Preventive effects of conjugated linoleic acid (CLA) in-vivo oral treatment in the SOD1G93A preclinical model of amyotrophic lateral sclerosis
No full textPatient-Oriented In Vitro Studies in Duchenne Muscular Dystrophy: Validation of a 3D Skeletal Muscle Organoid Platform
No full textBackground: Three-dimensional skeletal muscle organoids (3D SkMO) are becoming of increasing interest for preclinical studies in Duchenne muscular dystrophy (DMD), provided that the used platform demonstrates the possibility to form functional and reproducible 3D SkMOs, to investigate on potential patient-related phenotypic differences. Methods: In this study, we employed fibrin-based 3D skeletal muscle organoids derived from immortalized myogenic precursors of DMD patients carrying either a stop codon mutation in exon 59 or a 48–50 deletion. We compared dystrophic lines with a healthy wild-type control (HWT) by assessing microtissue formation ability, contractile function at multiple timepoints along with intracellular calcium dynamics via calcium imaging, as well as expression of myogenic markers. Results: We found patient-specific structural and functional differences in the early stages of 3D SkMO development. Contractile force, measured as both single twitch and tetanic responses, was significantly lower in dystrophic 3D SkMOs compared to HWT, with the most pronounced differences observed at day 7 of differentiation. However, these disparities diminished over time under similar culturing conditions and in the absence of continuous nerve-like stimulation, suggesting that the primary deficit lies in delayed myogenic maturation, as also supported by gene expression analysis. Conclusions: Our results underline that, despite the initial maturation delay, DMD muscle precursors retain the capacity to form functional 3D SkMOs once this intrinsic lag is overcome. This suggests a critical role of dystrophin in early myogenic development, while contraction-induced stress and/or an inflammatory microenvironment are essential to fully recapitulate dystrophic phenotypes in 3D SkMOs
Towards development of Nav1.7 channel modulators for pain treatment: A comparison of mexiletine effect in two cell models by automated patch clamp
No full textThe Nav1.7 voltage-gated sodium channel recently emerged as a candidate target for developing analgesic drugs due to its contribution to nociception and association with different pain disorders. Despite extensive research, no selective modulator of Nav1.7 has been put into clinic yet. Meanwhile, some non-selective sodium channel blockers, such as lidocaine and mexiletine (Mex), have been used for treating peripheral neuropathy and Nav1.7-related pain syndromes. The development of selective molecules targeting Nav1.7 channels requires robust preclinical tests integrating efficient electrophysiological screening with proper cell models. Here, we used the automated patch clamp platform, Patchliner (Nanion Technologies), and two different cell lines, the human rhabdomyosarcoma TE671 cells endogenously expressing Nav1.7 and HEK293 cells stably expressing heterologous human Nav1.7, to compare the biophysical properties and state-dependent effect of Mex on Nav1.7 channels. Our results show that in voltage-dependent conditions, Mex similarly blocked sodium currents in both cell lines (IC50: 226 ± 16 and 227 ± 14 μM, at −140 mV; 15 ± 1 and 12 ± 1 μM, at −70 mV, for TE671 and HEK293 cells). Likewise, Mex exerted a comparable tonic (0.3 Hz) and use-dependent (20 Hz) block in TE671 and in HEK293 cells (IC50: 96 ± 4 vs 114 ± 9 μM; IC50: 22 ± 2 and 18 ± 2 μM, at 0.3 Hz and 20 Hz). Moreover, Mex negatively shifted the voltage-dependence of inactivation of Nav1.7 channels in a dose-dependent manner in both cell lines. In conclusion, we confirmed the state-dependency of Mex block on Nav1.7 using automated patch clamp and validated two cell lines expressing Nav1.7 as suitable models for drug screening. This approach can help developing Nav1.7 modulators for the treatment of pain disorders
Preclinical study showing a gender specific protective properties of conjugated linoleic acid (CLA) for amyotrophic lateral sclerosis
No full textAmyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with no effective therapies, characterized by degeneration of motor neurons and muscle atrophy. Mitochondrial
dysfunction, oxidative stress, and inflammatory response are pathognomonic signs of ALS. In this scenario, a crucial role is played by the nuclear erythroid-related factor 2 (Nrf2).
Nrf2 has been indicated as a therapeutic target for ALS, but the efficacy Nrf2 activators has been limitedly investigated. Recent in-vivo pre-clinical studies showed that dietary
supplementation with the conjugated linoleic acid (CLA) activates Nrf2 in the liver of healthy animals and shows antioxidant effects towards age-dependent pro-inflammatory status.
We wanted to evaluate the effects of a daily oral administration of CLA (600 mg/kg/day) as dietary supplementation in SOD1G93A mice, starting from a pre-symptomatic stage of
the disease (60 post natal days). We recorded motor functional parameters and the progression of the pathology by in-vivo behavioral studies and ex-vivo biochemical analysis
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