Development of Octreotide-Loaded Chitosan and Heparin Nanoparticles: Evaluation of Surface Modification Effect on Physicochemical Properties and Macrophage Uptake

Octreotide (OCT) is a therapeutic peptide which is administered for the treatment of acromegaly. The purpose of this study was to design a new polyethylene glycol (PEG)–conjugated nanoparticle (PEG-NP) to overcome the short half-life and poor stability of OCT. The developed PEG-NPs were compared with non-PEGylated NPs with respect to their size, morphological characteristics, loading efficiency, release profile, and macrophage uptake. The OCT-loaded NPs and PEG-NPs were prepared by ionic complexion of chitosan (Cs) with either heparin (Hp) or PEGylated heparin (PEG-Hp). The chemical structure of PEG-Hp was confirmed by IR and proton nuclear magnetic resonance. Morphological analyses by scanning electron microscopy showed that NPs and PEG-NPs have a uniform shape. Dynamic laser scattering measurements indicated that hydrodynamic diameter of NPs and PEG-NPs were 222.5 ± 10.0 nm and 334.9 ± 6.7 nm, respectively. NPs and PEG-NPs had a positive zeta potential of about 32.5 ± 1.1 mv and 20.6 ± 2.4 mv, respectively. Entrapment efficiency was 61.4 ± 1.0% and 55.7 ± 2.4% for NPs and PEG-NPs, respectively. Compared with the NPs, the PEG-NPs exhibited a slower release profile. Subsequently, fluorescein isothiocyanate–labeled chitosanCs was synthesized and used to evaluate the stealth characteristic of PEG-NPs. In vitro macrophage uptake of fluorescently labeled NPs was measured by flow cytometry.     

Elosulfase alfa (BMN 110) for the treatment of mucopolysaccharidosis IVA (Morquio A Syndrome)

Introduction: Morquio A syndrome is a rare, autosomal recessive, lysosomal storage disorder caused by a deficiency in the enzyme N-acetylgalactosamine-6-sulfatase (GALNS). In 2014, the use of recombinant human GALNS, elosulfase alfa, was approved in the European Union, Canada, the United States, Australia, and Brazil for the treatment of Morquio A syndrome. Elosulfase alfa is administered intravenously once-weekly at a dose of 2.0 mg/kg.

Areas covered: This is a review of the efficacy, safety and tolerability, pharmacokinetics and pharmacodynamics, and other outcomes of elosulfase alfa treatment of patients with Morquio A. A discussion of other treatment considerations, limitations, and future directions in the use of elosulfase alfa is provided.

Expert commentary: Pharmacokinetic studies outside of clinical trials and in ‘real-world’ clinical settings need to be performed. We cannot currently predict which patient is going to respond well to enzyme replacement therapy; thus, all patients should be given the option to receive treatment for at least 12 months. Additionally, accurate biomarkers for evaluating disease state and drug responsiveness would greatly aid in the treatment of patients with Morquio A. In addition, improved and innovative daily lifestyle measures are greatly needed to adequately measure clinical response and true impact on quality of life.     

Developmental validation of STRmix™ NGS,a probabilistic genotyping tool for the interpretation of autosomal STRs from forensic profiles generated using NGS

We describe the developmental validation of the probabilistic genotyping software – STRmix™ NGS – developed for the interpretation of forensic DNA profiles containing autosomal STRs generated using next generation sequencing (NGS) also known as massively parallel sequencing (MPS) technologies. Developmental validation was carried out in accordance with the Scientific Working Group on DNA Analysis Methods (SWGDAM) Guidelines for the Validation of Probabilistic Genotyping Systems and the International Society for Forensic Genetics (ISFG) recommendations and included sensitivity and specificity testing, accuracy, precision, and the interpretation of case-types samples. The results of developmental validation demonstrate the appropriateness of the software for the interpretation of profiles developed using NGS technology.     

Mutational analysis of 105 mucopolysaccharidosis type VI patients

Mucopolysaccharidosis type VI (MPS VI; Maroteaux-Lamy syndrome) is a lysosomal storage disorder caused by mutations in the N-acetylgalactosamine-4-sulfatase (arylsulfatase B, ARSB) gene. ARSB is a lysosomal enzyme involved in the degradation of the glycosaminoglycans (GAG) dermatan and chondroitin sulfate. ARSB mutations reduce enzyme function and GAG degradation, causing lysosomal storage and urinary excretion of these partially degraded substrates. Disease onset and rate of progression is variable, producing a spectrum of clinical presentation. In this study, 105 MPS VI patients-representing about 10% of the world MPS VI population-were studied for molecular genetic and biochemical parameters. Direct sequencing of patient genomic DNA was used to identify ARSB mutations. In total, 83 different disease-causing mutations were found, 62 of which were previously unknown. The novel sequence changes included: 38 missense mutations, five nonsense mutations, 11 deletions, one insertion, seven splice-site mutations, and four polymorphisms. ARSB mutant protein and residual activity were determined on fibroblast extracts for each patient. The identification of many novel mutations unique to individuals/their families highlighted the genetic heterogeneity of the disorder and provided an appropriate cohort to study the MPS VI phenotypic spectrum. This mutation analysis has identified a clear correlation between genotype and urinary GAG that can be used to predict clinical outcome.     

Modality-specific sensory changes in humans after the induction of long-term potentiation (LTP) in cutaneous nociceptive pathways

The impact of long-term potentiation (LTP) in nociceptive pathways on somatosensory perception was examined by means of quantitative sensory testing (QST) in the ventral forearm of 12 healthy human subjects. Electrical high-frequency stimulation of the forearm skin (HFS; 5 x 1 s at 100 Hz and 10 x detection threshold) led to an abrupt increase of pain to single electrical test stimuli, which were applied through the same electrode (perceptual LTP +72%, p<0.01). Perceptual LTP outlasted the 1-h observation period. The effects of HFS on somatosensory perception of natural test stimuli in the conditioned skin area were restricted to mechanical submodalities. Subjects exhibited a significant decrease of pain threshold and an increase of pain ratings to suprathreshold pinprick stimuli (p<0.01). In 5 out of 12 subjects (42%) light tactile stimuli led to painful sensations (dynamic mechanical allodynia). Furthermore, a small but significant decrease of threshold to blunt pressure stimuli (p<0.05) was found. In contrast, all thermal modalities comprising cold and warm detection thresholds, cold and heat pain thresholds as well as pain summation (perceptual wind up) remained unaltered. These data show that HFS of peptidergic cutaneous C-fiber afferents predominantly modulates Adelta- and Abeta-fiber mediated somatosensory functions, suggesting that LTP in nociceptive pathways enhances human pain sensitivity via interaction of two afferent pathways (extrinsic sensitization).     

Residual activity and proteasomal degradation of p.Ser298Pro sulfamidase identified in patients with a mild clinical phenotype of Sanfilippo A syndrome

Mucopolysaccharidosis type IIIA (MPS IIIA, Sanfilippo syndrome) is a fatal inherited lysosomal storage disease accompanied by progressive neurologic degeneration. The gene underlying MPS IIIA, SGSH, encodes a lysosomal enzyme, N-sulfoglucosamine sulfohydrolase (sulfamidase). Mutational analysis of a large cohort of MPS IIIA patients showed a correlation of the missense mutation p.Ser298Pro and a slowly progressive course of the disease. We report here on the expression of the mutant p.Ser298Pro sulfamidase in BHK cells retaining low residual activity. Pulse-chase experiments showed that rapid degradation is responsible for the low steady state level of the mutant protein. Processing and secretion of p.Ser298Pro sulfamidase suggests that small amounts of the newly synthesized enzyme are transported to lysosomes. Most of the mutant sulfamidase exits the endoplasmic reticulum for proteasomal degradation. The ability to predict the clinical course of MPS IIIA in patients with the p.Ser298Pro mutation, as well as the residual enzymatic activity, and the reduced stability of the mutant sulfamidase suggest that this subgroup of patients is especially well suited to early sulfamidase replacement therapy or treatment with selective pharmacological chaperones.     

Use of experimental design methodology for the development of new magnetic siRNA nanovectors (MSN)

Short interfering RNAs (siRNAs) can downregulate the synthesis of proteins and thus be used to treat certain diseases where the protein synthesis is upregulated, such as cancer. The challenge is to deliver siRNAs in the target cell as they are rapidly degraded by nucleases and have difficulties to cross the cellular membranes. Superparamagnetic iron oxide nanoparticles (SPIONs) are widely studied as platforms for smart biocompatible nanosystems which can be used for magnetic drug targeting and magnetic resonance imaging.     

Mucopolysaccharidosis IVA within Tunisian patients: Confirmation of the two novel GALNS gene mutations

Mucopolysaccharidosis type IVA or Morquio A disease is an autosomal recessive disease resulting from a deficiency of the lysosomal enzyme N-acetylgalactosamine-6-sulfate-sulfatase, which hydrolyses N-acetylgalactosamine-6-sulfate and galactose-6-sulfate in glycosaminoglycans. Phenotypes in Morquio A disease vary from the classical form with severe bone dysplasia, heart valve involvement, corneal opacity, short trunk dwarfism and a life span of 20 to 30 years, to attenuated forms with normal life span, mild bone involvement and mild visceral organ involvement. Unlike the other forms of mucopolysaccharidoses, Morquio A disease is characterized by normal intelligence.