Nanotechnology-novel therapeutics for CNS disorders.
ABSTRACT Research into treatments for diseases of the CNS has made impressive strides in the past few decades, but therapeutic options are limited for many patients with CNS disorders. Nanotechnology has emerged as an exciting and promising new means of treating neurological disease, with the potential to fundamentally change the way we approach CNS-targeted therapeutics. Molecules can be nanoengineered to cross the blood-brain barrier, target specific cell or signalling systems, respond to endogenous stimuli, or act as vehicles for gene delivery, or as a matrix to promote axon elongation and support cell survival. The wide variety of available nanotechnologies allows the selection of a nanoscale material with the characteristics best suited to the therapeutic challenges posed by an individual CNS disorder. In this Review, we describe recent advances in the development of nanotechnology for the treatment of neurological disorders-in particular, neurodegenerative disease and malignant brain tumours-and for the promotion of neuroregeneration.
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ABSTRACT: Oxidative stress may contribute to nigral cell death in Parkinson's disease based on postmortem investigations showing increased iron levels, decreased levels of reduced glutathione (GSH), and impaired mitochondrial function. This leads to oxidative damage because lipid peroxidation is increased in substantia nigra and there is a widespread increase in protein and DNA oxidation in the brain in Parkinson's disease. Nitric oxide (NO) may be one of the free radical species involved in nigral degeneration. NO is involved in the production of hydroxyl radicals resulting from MPP+-induced dopamine efflux in striatum. Mice treated with the neuronal nitric oxide synthase (NOS) inhibitor 7-nitroindazole show reduced toxicity to MPTP and knock-out mice lacking neuronal NOS show decreased MPTP susceptibility. In primates, 7-nitroindazole inhibits MPTP toxicity but this remains controversial because no protection is afforded by the nonspecific NOS inhibitor, L-NAME. Indeed, in Parkinson's disease itself, there is little evidence for nitric oxide's involvement in nigral pathology. A susceptibility factor for the development of Parkinson's disease may involve isoforms of cytochrome P450, some of which are found in the brain. CYP2EI, which is associated with free radical production and the formation of endogenous toxins, is selectively localized in nigral dopamine-containing cells. CYP2E1 metabolizes n-hexane leading to the formation of its neurotoxic metabolite 2,5-hexanedione which may explain cases of solvent-induced parkinsonism. Oxidative processes clearly contribute to the pathology of Parkinson's disease but are probably secondary to some other primary unidentified cause, presumably genetic or environmental. Nevertheless, their involvement may allow therapeutic intervention in the cascade of events associated with the progression of Parkinson's disease.Movement Disorders 02/1998; 13 Suppl 1:24-34. · 4.56 Impact Factor
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ABSTRACT: The blood-brain barrier (BBB) restricts the entry of proteins as well as potential drugs to cerebral tissues. We previously reported that a family of Kunitz domain-derived peptides called Angiopeps can be used as a drug delivery system for the brain. Here, we further characterize the transcytosis ability of these peptides using an in vitro model of the BBB and in situ brain perfusion. These peptides, and in particular Angiopep-2, exhibited higher transcytosis capacity and parenchymal accumulation than do transferrin, lactoferrin, and avidin. Angiopep-2 transport and accumulation in brain endothelial cells were unaffected by the P-glycoprotein inhibitor, cyclosporin A, indicating that this peptide is not a substrate for the efflux pump P-glycoprotein. However, competition studies show that activated alpha(2)-macroglobulin, a specific ligand for the low-density lipoprotein receptor-related protein-1 (LRP1) and Angiopep-2 can share the same receptor. In addition, LRP1 was detected in glioblastomas and brain metastases from lung and skin cancers. Fluorescent microscopy also revealed that Alexa488-Angiopep-2 co-localized with LRP1 in brain endothelial cell monolayers. Overall, these results suggest that Angiopep-2 transport across the BBB is, in part, mediated by LRP1.Journal of Neurochemistry 07/2008; 106(4):1534-44. · 3.97 Impact Factor
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ABSTRACT: Cholinesterase inhibitors are the primary treatment for the cognitive symptoms of Alzheimer disease (AD). Cholinergic dysfunction is also associated with neuropsychiatric and functional deficits, but results from randomized controlled trials of cholinesterase inhibitors are conflicting. To conduct a systematic review and meta-analysis to quantify the efficacy of cholinesterase inhibitors for neuropsychiatric and functional outcomes in patients with mild to moderate AD. We performed a literature search of trials using MEDLINE (January 1966-December 2001), Dissertations Abstracts On-line, PSYCHINFO, BIOSIS, PubMed, and the Cochrane Controlled Trials Register. We retrieved English- and non-English-language articles for review and collected references from bibliographies of reviews, original research articles, and other articles of interest. We searched for both published and unpublished trials, contacting researchers and pharmaceutical companies. We included 29 parallel-group or crossover randomized, double-blind, placebo-controlled trials of outpatients who were diagnosed as having mild to moderate probable AD and were treated for at least 1 month with a cholinesterase inhibitor. Sixteen trials included neuropsychiatric and 18 included functional measures. Two investigators (N.H.T. and J.H.) independently extracted study methods, sources of bias, and outcomes. Neuropsychiatric outcomes were measured with the Neuropsychiatric Inventory (NPI, 0-120 points) and the Alzheimer Disease Assessment Scale, noncognitive (ADAS-noncog, 0-50 points) and were analyzed with the weighted mean difference method. Functional outcomes were measured with several activities of daily living (ADL) and instrumental activities of daily living (IADL) scales and analyzed with the standardized mean difference method. For neuropsychiatric outcomes, 10 trials included the ADAS-noncog and 6 included the NPI. Compared with placebo, patients randomized to cholinesterase inhibitors improved 1.72 points on the NPI (95% confidence interval [CI], 0.87-2.57 points), and 0.03 points on the ADAS-noncog (95% CI, 0.00-0.05 points). For functional outcomes, 14 trials used ADL and 13 trials used IADL scales. Compared with placebo, patients randomized to cholinesterase inhibitors improved 0.1 SDs on ADL scales (95% CI, 0.00-0.19 SDs), and 0.09 SDs on IADL scales (95% CI, 0.01 to 0.17 SDs). There was no difference in efficacy among various cholinesterase inhibitors. These results indicate that cholinesterase inhibitors have a modest beneficial impact on neuropsychiatric and functional outcomes for patients with AD. Future research should focus on how such improvements translate into long-term outcomes such as patient quality of life, institutionalization, and caregiver burden.JAMA The Journal of the American Medical Association 02/2003; 289(2):210-6. · 29.98 Impact Factor