Single intranasal administration of 17ß-estradiol loaded gelatin nanoparticles confers neuroprotection in the post-ischemic brain.

Globally, ischemic stroke is a leading cause of death and adult disability. Previous efforts to repair damaged brain tissue following ischemic events have been hindered by the relative isolation of the central nervous system. We have developed a gelatin nanoparticle-mediated intranasal drug delivery system as an efficient, non-invasive method for delivering 17ß-estradiol (E2) specifically to the brain, enhancing neuroprotection, and limiting systemic side effects. Young adult male C57BL/6 J mice subjected to 30 min of middle cerebral artery occlusion (MCAO) were administered intranasal preparations of E2-GNPs, water soluble E2, or saline as control 1 h after reperfusion. Following intranasal administration of 500 ng E2-GNPs, brain E2 content rose by 5.24 fold (P<0.0001) after 30 min and remained elevated by 2.5 fold at 2 h (P<0.05). The 100 ng dose of E2-GNPs reduced mean infarct volume by 54.3% (P<0.05, n=4) in comparison to saline treated controls, demonstrating our intranasal delivery system's efficacy.

Toxicity of silica nanoparticles depends on size, dose, and cell type.

Monodisperse spherical silica nanoparticles (SNPs) with diameters of 20-200 nm were employed to study size, dose, and cell-type dependent cytotoxicity in A549 and HepG2 epithelial cells and NIH/3T3 fibroblasts. These uniform SNPs of precisely controlled sizes eliminated uncertainties arising from mixed sizes, and uniquely allowed the probing of effects entirely size-dependent. Cell viability, membrane disruption, oxidative stress, and cellular uptake were studied. The extent and mechanism of SNP cytotoxicity were found to be not only size and dose dependent, but also highly cell type dependent. Furthermore, the 60 nm SNPs exhibited highly unusual behavior in comparison to particles of other sizes tested, implying interesting possibilities for controlling cellular activities using nanoparticles. Specifically, the 60 nm SNPs were preferentially endocytosed by cells and, at high doses, caused a disproportionate decrease in cell viability. The present work may help elucidate certain contradictions among existing results on nanoparticle-induced cytotoxicity. FROM THE CLINICAL EDITOR: Silica nanoparticles are being investigated in many research areas for their use in clinical applications. Nonetheless, the relationship between particle size and potential toxicity remains to be elucidated. In this article, the authors studied the biological effects of spherical SNPs with precise diameters between 20 and 200 nm on three different cell types and their results should provide more data on safety for better drug design.

Gelatin nanoparticles enhance the neuroprotective effects of intranasally administered osteopontin in rat ischemic stroke model.

As a leading cause of death and adult disability, ischemic stroke requires the development of non-invasive, long-acting treatments. Osteopontin (OPN) is an endogenous protein shown to have neuroprotective effects in the post-ischemic brain of rats when administered through the non-invasive, intranasal pathway. Previously, gelatin microspheres (GMSs) have been shown to enhance the neuroprotective effects of OPN when used as a carrier during instrastriatal administration, but GMSs are generally too large to enter the brain parenchyma following intranasal administration. Here, gelatin nanoparticles (GNPs) were investigated as a carrier for intranasal delivery of an OPN peptide for the treatment of ischemic stroke. We not only successfully fabricated GNPs with a uniform shape, but also demonstrated the ability of these GNPs to pass into the brain parenchyma following intranasal administration. Critically, the use of GNPs as a carrier allowed for a 71.57 % reduction in mean infarct volume and extended the therapeutic window of intranasally administered OPN peptide to at least 6 h post-middle cerebral artery occlusion (MCAO). Our findings support the development of GNPs as a promising drug delivery platform for the intranasal treatment of ischemic stroke and, potentially, other neurologic disorders.