Publications by authors named "Lourbakos A"

Objective: This double-blind, randomized, placebo-controlled Phase 2 study (NCT01462292) assessed the 24-week efficacy, safety, tolerability, and pharmacokinetics of two different subcutaneous drisapersen doses, and the 24-week off-dose persistent effect, in ambulant Duchenne muscular dystrophy (DMD) patients.

Methods: Male DMD patients (≥5 years; time to rise from floor ≤15 s) were randomized to drisapersen 3 mg/kg/week, 6 mg/kg/week or placebo. The primary efficacy endpoint was change from baseline in 6-minute walking distance (6MWD) at week 24.

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Duchenne Muscular Dystrophy (DMD) is a severe muscle disorder caused by lack of dystrophin. Predictive biomarkers able to anticipate response to the therapeutic treatments aiming at dystrophin re-expression are lacking. The objective of this study is to investigate Matrix Metalloproteinase-9 (MMP-9) as predictive biomarker for Duchenne.

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This 48-week, randomized, placebo-controlled phase 3 study (DMD114044; NCT01254019) evaluated efficacy and safety of subcutaneous drisapersen 6 mg/kg/week in 186 ambulant boys aged ≥5 years, with Duchenne muscular dystrophy (DMD) resulting from an exon 51 skipping amenable mutation. Drisapersen was generally well tolerated, with injection-site reactions and renal events as most commonly reported adverse events. A nonsignificant treatment difference (P = 0.

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Background: Drisapersen induces exon 51 skipping during dystrophin pre-mRNA splicing and allows synthesis of partially functional dystrophin in Duchenne muscular dystrophy (DMD) patients with amenable mutations.

Methods: This 188-week open-label extension of the dose-escalation study assessed the long-term efficacy, safety, and pharmacokinetics of drisapersen (PRO051/GSK2402968), 6 mg/kg subcutaneously, in 12 DMD subjects. Dosing was once weekly for 72 weeks.

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Article Synopsis
  • A multi-institution collaboration was established to evaluate and compare different methods for measuring dystrophin levels in muscle biopsies, aiming for a reliable consensus and understanding of its clinical significance.
  • Five expert laboratories conducted a detailed analysis of muscle samples using quantitative immunohistochemistry and Western blotting, ensuring standardized protocols to evaluate variability.
  • The study found strong agreement in results across laboratories, with quantitative immunohistochemistry showing greater sensitivity, confirming that these methods can effectively measure dystrophin for clinical trials in Duchenne muscular dystrophy and aid in therapy development.
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Duchenne muscular dystrophy (DMD) is characterized by the absence or reduced levels of dystrophin expression on the inner surface of the sarcolemmal membrane of muscle fibers. Clinical development of therapeutic approaches aiming to increase dystrophin levels requires sensitive and reproducible measurement of differences in dystrophin expression in muscle biopsies of treated patients with DMD. This, however, poses a technical challenge due to intra- and inter-donor variance in the occurrence of revertant fibers and low trace dystrophin expression throughout the biopsies.

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Background: Duchenne muscular dystrophy is caused by dystrophin deficiency and muscle deterioration and preferentially affects boys. Antisense-oligonucleotide-induced exon skipping allows synthesis of partially functional dystrophin. We investigated the efficacy and safety of drisapersen, a 2'-O-methyl-phosphorothioate antisense oligonucleotide, given for 48 weeks.

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Protein has been reported to be the most satiating of all macronutrients. Upon gastrointestinal digestion, peptides are generated that stimulate the release of satiety hormones such as cholecystokinin (CCK) from enteroendocrine cells. As such, bioactive peptides could be the target of Functional Food ingredients with satiating effects.

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Phytosterols are structurally similar to cholesterol. Increased dietary intake of phytosterols effectively lowers LDL-cholesterol. Since phytosterols are incorporated in a growing number of foods and some of the ingested phytosterols reach the circulation, accumulation of phytosterols in foam-cell-prone cells such as macrophages might occur.

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Alpha(1)-antitrypsin functions as a "mousetrap" to inhibit its target proteinase, neutrophil elastase. The common severe Z deficiency variant (Glu(342)-->Lys) destabilizes the mousetrap to allow a sequential protein-protein interaction between the reactive-centre loop of one molecule and beta-sheet A of another. These loop-sheet polymers accumulate within hepatocytes to form inclusion bodies that are associated with juvenile cirrhosis and hepatocellular carcinoma.

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Periodontitis is a chronic inflammatory disease affecting oral tissues. Oral epithelial cells represent the primary barrier against bacteria causing the disease. We examined the responses of such cells to an arginine-specific cysteine proteinase (RgpB) produced by a causative agent of periodontal disease, Porphyromonas gingivalis.

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The bacterium Porphyromonas gingivalis is a major etiologic agent in the pathogenesis of adult periodontitis in humans. Cysteine proteinases produced by this pathogen, termed gingipains, are considered to be important virulence factors. Among many other potentially deleterious activities, arginine-specific gingipains-R (RgpB and HRgpA) efficiently activate coagulation factors.

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Proteinase-activated receptor-2 (PAR-2) is a member of a family of G-protein-coupled, seven-transmembrane domain receptors that are activated by proteolytic cleavage. The receptor is expressed in a number of different tissues and potential physiological activators identified thus far include trypsin and mast cell tryptase. Acrosin, a trypsin-like serine proteinase found in spermatozoa of all mammals, was found to cleave a model peptide fluorescent quenched substrate representing the cleavage site of PAR-2.

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Osteoblasts express protease-activated receptor-1 (PAR-1), which is activated by thrombin or by synthetic peptides corresponding to the new "tethered ligand" N-terminus of PAR-1 created by receptor cleavage. Both thrombin and human PAR-1-activating peptide stimulate an elevation of [Ca2+]i in the human SaOS-2 osteoblast-like cell line, but the peptide stimulates receptor-mediated Ca+ entry, whereas thrombin does not. Stimulation of proliferation in rat primary osteoblast-like cells is greater in response to rat PAR-1-activating peptide than to thrombin.

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Gingipain-R, the major arginine-specific proteinase from Porphyromonas gingivalis, a causative agent of adult periodontal disease, was found to cleave a model peptide representing the cleavage site of proteinase-activated receptor-2 (PAR-2), a G-protein-coupled receptor found on the surface of neutrophils. The bacterial proteinase was also shown to induce an increase in the intracellular calcium concentration of enzyme-treated neutrophils, most probably due to PAR-2 activation. This response by neutrophils to gingipain-R may be a mechanism for the development of inflammation associated with periodontal disease.

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We have shown that OSCP, a subunit of yeast mitochondrial ATP synthase, can be incorporated into the intact enzyme as a fusion protein representing OSCP fused at its C-terminus to the green fluorescent protein (GFP) of Aequorea victoria. The relevant fusion OSCP-GFP-h6 additionally contains a hexahistidine tag at the C-terminus. Expression of OSCP-GFP-h6 in yeast cells lacking endogenous OSCP led to the efficient restoration of growth of cells on the non-fermentable substrate, ethanol.

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