Overcoming therapeutic obstacles in inflammatory bowel diseases: a comprehensive review on novel drug delivery strategies.

Inflammatory bowel diseases (IBDs) are a group of debilitating inflammatory complications specially inflicting colonic tissue in which full long term remission with current standardized treatments is yet intangible. Therapeutic side effects and efficacy considerations necessitate the development of more effective systems which lower the required drug doses, reduce systemic adverse effects and deliver the drug specifically to the desired site of action in colon. The large surface area in large intestine is suitable for drug absorption but the primary approaches to treatment depend on the gastrointestinal (GI) condition and its movements. Hereafter, there are novel GI-independent targeted drug delivery systems or therapeutic approaches, including micro- and nanoparticles that have been developed for IBD treatment and have the potential to overcome some of the current drawbacks of conventional IBD therapy. This review provides broad but concise information over the arena of the evolving systems aimed at different targets involved in IBD which are being studied in animal or in vitro models of this complication, while comparing these to conventional treatments. It further discusses important pros and cons of therapeutic approaches against IBD while helping to better understand and evaluate the future impact of novel drug delivery systems on human IBD and assisting in focusing the future research in this topic, on strategies which could provide maximum remission in IBD patients.

Hydrogen sulfide restores a normal morphological phenotype in Werner syndrome fibroblasts, attenuates oxidative damage and modulates mTOR pathway.

Werner syndrome (WS) protein is involved in DNA repair and its truncation causes Werner syndrome, an autosomal recessive genetic disorder with a premature aging phenotype. WRN protein mutation is currently known as the primary cause of WS. In cultured WS fibroblasts, we found an increase in cytosolic aggregates and hypothesized that the phenotype is indirectly related to an excess activation of the mTOR (mammalian target of rapamycin) pathway, leading to the formation of protein aggregates in the cytosol with increasing levels of oxidative stress. As we found that the expression levels of the two main H2S producing enzymes, cystathionine ß synthase and cystathionine γ lyase, were lower in WS cells compared to normal, we investigated the effect of administration of H2S as NaHS (50µM). NaHS treatment blocked mTOR activity, abrogated protein aggregation and normalized the phenotype of WS cells. Similar results were obtained by treatment with the mTOR inhibitor rapamycin. This is the first report suggesting that hydrogen sulfide administered as NaHS restores proteostasis and cellular morphological phenotype of WS cells and hints to the importance of transsulfuration pathway in WS.

Core shell methyl methacrylate chitosan nanoparticles: In vitro mucoadhesion and complement activation.

BACKGROUND AND THE PURPOSE OF THE STUDY: Studies show that chitosan nanoparticles increase mucoadhesivity and penetration of large molecules across mucosal surface. The aim of the present study was to investigate the use of thiolated chitosan in the development of polysaccharide-coated nanoparticles in order to confer specific functionality to the system. METHODS: Methyl methacrylate nanoparticles were coated with thiolated chitosan using a radical polymerization method. Thiolation was carried out using glutathione (GSH) to improve mucoadhesivity and permeation enhancing properties of chitosan. Mucoadhesion studies were carried out by calculating the amount of mucin adsorbed on nanoparticles in a specific period of time. Complement consumption was assessed in human serum (HS) by measurement of the hemolytic capacity of the complement system after contact with nanoparticles. RESULTS: The FT-IR and (1)HNMR spectra both confirmed the synthesis and showed the conjugation of thiolated chitosan to methyl methacrylate (MMA) homopolymer. Nanoparticles were spherical having a mean diameter within the range of about 334-650 nm and their positive zeta potential values indicated the presence of the cationic polysaccharide at the nanoparticle surface. Increasing the amount of thiolated chitosan led to mucoadhesivity and complement activation. However there was not dose dependent correlation between these phenomenons and the absence of thiolated chitosan led to particles with larger size, and without ability to activate complement process. MAJOR CONCLUSION: It can be concluded that nanoparticles could be used for the mucosal delivery of peptides and proteins. Results show that the thiolated chitosan had higher mucoadhesion and complement activation than unmodified chitosan.