Encapsulated cell biodelivery of GDNF: A novel clinical strategy for neuroprotection and neuroregeneration in Parkinson's disease?
ABSTRACT The main pathology underlying disease symptoms in Parkinson's disease (PD) is a progressive degeneration of nigrostriatal dopamine (DA) neurons. No effective disease-modifying treatment currently exists. Glial cell line-derived neurotrophic factor (GDNF) has neuroprotective and neuroregenerative effects and it enhances dopaminergic function in animal models of PD. These findings raise the possibility that intrastriatal administration of GDNF might be developed into a new clinical strategy for functional preservation and restoration also in PD patients. Gene therapy is a novel tool to increase local levels of GDNF. Transplantation of encapsulated, GDNF-secreting cells is one strategy for ex vivo cell-based gene delivery which has the advantage to allow for removal of the cells if untoward effects occur. Here we summarize studies with such cells in animals, and discuss the results from previous trials with GDNF in PD patients and their implications for the further development of neuroprotective/neuroregenerative therapies. Finally, we describe the different scientific and regulatory issues that need to be addressed in order to reach the clinic and start the first trial in patients.
SourceAvailable from: Alberto Pascual[Show abstract] [Hide abstract]
ABSTRACT: The glial cell line-derived neurotrophic factor (GDNF) is a well-established trophic agent for dopaminergic (DA) neurons in vitro and in vivo. GDNF is necessary for maintenance of neuronal morphological and neurochemical phenotype and protects DA neurons from toxic damage. Numerous studies on animal models of Parkinson's disease (PD) have reported beneficial effects of GDNF on nigrostriatal DA neuron survival. However, translation of these observations to the clinical setting has been hampered so far by side effects associated with the chronic continuous intra-striatal infusion of recombinant GDNF. In addition, double blind and placebo-controlled clinical trials have not reported any clinically relevant effect of GDNF on PD patients. In the past few years, experiments with conditional Gdnf knockout mice have suggested that GDNF is necessary for maintenance of DA neurons in adulthood. In parallel, new methodologies for exogenous GDNF delivery have been developed. Recently, it has been shown that a small population of scattered, electrically interconnected, parvalbumin positive (PV+) GABAergic interneurons is responsible for most of the GDNF produced in the rodent striatum. In addition, cholinergic striatal interneurons appear to be also involved in the modulation of striatal GDNF. In this review, we summarize current knowledge on brain GDNF delivery, homeostasis, and its effects on nigrostriatal DA neurons. Special attention is paid to the therapeutic potential of endogenous GDNF stimulation in PD.Frontiers in Neuroanatomy 01/2015; 9:10. DOI:10.3389/fnana.2015.00010 · 4.18 Impact Factor
Article: Neurodegenerative Disorders[Show abstract] [Hide abstract]
ABSTRACT: Parkinson's disease (PD) is characterized by a progressive loss of dopaminergic neurons and represents a growing health burden to western societies. Like many neurodegenerative disorders the cause is unknown, however, as the pathogenesis becomes ever more elucidated, it is becoming clear that effective delivery is a key issue for new therapeutics. The versatility of today's polymerization techniques allows the synthesis of a wide range of polymer materials which hold great potential to aid in the delivery of small molecules, proteins, genetic material or cells. In this review, we capture the recent advances in polymer based therapeutics of the central nervous system (CNS). We place the advances in historical context and, furthermore, provide future prospects in line with newly discovered advancements in the understanding of PD and other neurodegenerative disorders. This review provides researchers in the field of polymer chemistry and materials science an up-to-date understanding of the requirements placed upon materials designed for use in the CNS aiding the focus of polymer therapeutic design.
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ABSTRACT: Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease whose pathophysiology is poorly understood. Aiming to better understand the cause of motor neuron death, the use of experimental cell-based models increased significantly over the past years. In this scenario, much knowledge has been generated from the study of motor neurons derived from embryonic stem cells and induced pluripotent stem cells. These methods, however, have advantages and disadvantages, which must be balanced on experimental design. Preclinical studies provide valuable information, making it possible to combine diverse methods to build an expanded knowledge of ALS pathophysiology. In addition to using stem cells as experimental models for understanding disease mechanism, these cells had been quoted for therapy in ALS. Despite ethical issues involved in its use, cell therapy with neural stem cells stands out. A phase I clinical trial was recently completed and a phase II is on its way, attesting the method's safety. In another approach, mesenchymal stromal cells capable of releasing neuroregulatory and anti-inflammatory factors have also been listed as candidates for cell therapy for ALS, and have been admitted as safe in a phase I trial. Despite recent advances, application of stem cells as an actual therapy for ALS patients is still in debate. Here, we discuss how stem cells have been useful in modeling ALS and address critical topics concerning their therapeutic use, such as administration protocols, injection site, cell type to be administered, type of transplantation (autologous vs. allogeneic) among other issues with particular implications for ALS therapy. © 2015 International Society for Advancement of CytometryCytometry Part A 02/2015; 87(3). DOI:10.1002/cyto.a.22630 · 3.07 Impact Factor