Liposomal-glutathione provides maintenance of intracellular glutathione and neuroprotection in mesencephalic neuronal cells

Lipidic Nanoparticles, Extracellular Vesicles and Hybrid Platforms as Advanced Medicinal Products: Future Therapeutic Prospects for Neurodegenerative Diseases

Neurodegenerative diseases, such as Alzheimer's and Parkinson's, affect a wide variety of the population and pose significant challenges with progressive and irreversible neural cell loss. The limitations of brain-targeting therapies and the unclear molecular mechanisms driving neurodegeneration hamper the possibility of developing successful treatment options. Thus, nanoscale drug delivery platforms offer a promising solution. This paper explores and compares lipidic nanoparticles, extracellular vesicles (EVs), and hybrid liposomal-EV nanoplatforms as advanced approaches for targeted delivery to combat neurodegeneration. Lipidic nanoparticles are well-characterized platforms that allow multi-drug loading and scalable production. Conversely, EVs offer the ability of selectively targeting specific tissues and high biocompatibility. The combination of these two platforms in one could lead to promising results in the treatment of neurodegeneration. However, many issues, such as the regulatory framework, remain to be solved before these novel products are translated into clinical practice.

Mitochondrial dysfunction in Parkinson's disease - a key disease hallmark with therapeutic potential

Mitochondrial dysfunction is strongly implicated in the etiology of idiopathic and genetic Parkinson's disease (PD). However, strategies aimed at ameliorating mitochondrial dysfunction, including antioxidants, antidiabetic drugs, and iron chelators, have failed in disease-modification clinical trials. In this review, we summarize the cellular determinants of mitochondrial dysfunction, including impairment of electron transport chain complex 1, increased oxidative stress, disturbed mitochondrial quality control mechanisms, and cellular bioenergetic deficiency. In addition, we outline mitochondrial pathways to neurodegeneration in the current context of PD pathogenesis, and review past and current treatment strategies in an attempt to better understand why translational efforts thus far have been unsuccessful.

Combating Dopaminergic Neurodegeneration in Parkinson's Disease through Nanovesicle Technology

Parkinson's disease (PD) is characterized by dopaminergic neurodegeneration, resulting in dopamine depletion and motor behavior deficits. Since the discovery of L-DOPA, it has been the most prescribed drug for symptomatic relief in PD, whose prolonged use, however, causes undesirable motor fluctuations like dyskinesia and dystonia. Further, therapeutics targeting the pathological hallmarks of PD including α-synuclein aggregation, oxidative stress, neuroinflammation, and autophagy impairment have also been developed, yet PD treatment is a largely unmet success. The inception of the nanovesicle-based drug delivery approach over the past few decades brings add-on advantages to the therapeutic strategies for PD treatment in which nanovesicles (basically phospholipid-containing artificial structures) are used to load and deliver drugs to the target site of the body. The present review narrates the characteristic features of nanovesicles including their blood-brain barrier permeability and ability to reach dopaminergic neurons of the brain and finally discusses the current status of this technology in the treatment of PD. From the review, it becomes evident that with the assistance of nanovesicle technology, the therapeutic efficacy of anti-PD pharmaceuticals, phyto-compounds, as well as that of nucleic acids targeting α-synuclein aggregation gained a significant increment. Furthermore, owing to the multiple drug-carrying abilities of nanovesicles, combination therapy targeting multiple pathogenic events of PD has also found success in preclinical studies and will plausibly lead to effective treatment strategies in the near future.

Nanoparticle approaches for the renin-angiotensin system

The renin-angiotensin system (RAS) is a hormonal cascade that contributes to several disorders: systemic hypertension, heart failure, kidney disease, and neurodegenerative disease. Activation of the RAS can promote inflammation and fibrosis. Drugs that target the RAS can be classified into 3 categories, AT1 angiotensin receptor blockers (ARBs), angiotensin-converting enzyme (ACE) inhibitors, and renin inhibitors. The therapeutic efficacy of current RAS-inhibiting drugs is limited by poor penetration across the blood-brain barrier, low bioavailability, and to some extent, short half-lives. Nanoparticle-mediated drug delivery systems (DDSs) are possible emerging alternatives to overcome such limitations. Nanoparticles are ideally 1-100 nm in size and are considered efficient DDSs mainly due to their unique characteristics, including water dispersity, prolonged half-life in blood circulation, smaller size, and biocompatibility. Nano-scale DDSs can reduce the drug dosage frequency and acute toxicity of drugs while enhancing therapeutic success. Different types of nanoparticles, such as chitosan, polymeric, and nanofibers, have been examined in RAS-related studies, especially in hypertension, cardiovascular disease, and COVID-19. In this review article, we summarize the physical and chemical characteristics of each nanoparticle to elaborate on their potential use in RAS-related nano-drug delivery research and clinical application.

Glutathione and Related Molecules in Parkinsonism

Glutathione (GSH) is the most abundant intrinsic antioxidant in the central nervous system, and its substrate cysteine readily becomes the oxidized dimeric cystine. Since neurons lack a cystine transport system, neuronal GSH synthesis depends on cystine uptake via the cystine/glutamate exchange transporter (xCT), GSH synthesis, and release in/from surrounding astrocytes. Transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), a detoxifying master transcription factor, is expressed mainly in astrocytes and activates the gene expression of various phase II drug-metabolizing enzymes or antioxidants including GSH-related molecules and metallothionein by binding to the antioxidant response element (ARE) of these genes. Accumulating evidence has shown the involvement of dysfunction of antioxidative molecules including GSH and its related molecules in the pathogenesis of Parkinson’s disease (PD) or parkinsonian models. Furthermore, we found several agents targeting GSH synthesis in the astrocytes that protect nigrostriatal dopaminergic neuronal loss in PD models. In this article, the neuroprotective effects of supplementation and enhancement of GSH and its related molecules in PD pathology are reviewed, along with introducing new experimental findings, especially targeting of the xCT-GSH synthetic system and Nrf2–ARE pathway in astrocytes.

Glutathione: An Old and Small Molecule with Great Functions and New Applications in the Brain and in Alzheimer's Disease

Significance: Glutathione (GSH) represents the most abundant and the main antioxidant in the body with important functions in the brain related to Alzheimer's disease (AD). Recent Advances: Oxidative stress is one of the central mechanisms in AD. We and others have demonstrated the alteration of GSH levels in the AD brain, its important role in the detoxification of advanced glycation end-products and of acrolein, a by-product of lipid peroxidation. Recent in vivo studies found a decrease of GSH in several areas of the brain from control, mild cognitive impairment, and AD subjects, which are correlated with cognitive decline. Critical Issues: Several strategies were developed to restore its intracellular level with the l-cysteine prodrugs or the oral administration of γ-glutamylcysteine to prevent alterations observed in AD. To date, no benefit on GSH level or on oxidative biomarkers has been reported in clinical trials. Thus, it remains uncertain if GSH could be considered a potential preventive or therapeutic approach or a biomarker for AD. Future Directions: We address how GSH-coupled nanocarriers represent a promising approach for the functionalization of nanocarriers to overcome the blood/brain barrier (BBB) for the brain delivery of GSH while avoiding cellular toxicity. It is also important to address the presence of GSH in exosomes for its potential intercellular transfer or its shuttle across the BBB under certain conditions. Antioxid. Redox Signal. 35, 270-292.

β-Caryophyllene Liposomes Attenuate Neurovascular Unit Damage After Subarachnoid Hemorrhage in Rats

This study was conducted to prepare β-caryophyllene loaded liposomes (BCP-LP) and investigated their effects on neurovascular unit (NVU) damage after subarachnoid hemorrhage (SAH) in rats. A blood injection into the pre-chiasmatic cistern was used to achieve SAH. BCP-LP were prepared, characterized and administrated to rats with SAH. The prepared BCP-LP were spherical with a size distribution of approximately 189.3 nm and Zeta potential of - 13.9 mV. Neurological scoring, the balance beam test, cerebral blood flow monitoring, brain edema and biochemical analyses were applied to evaluate the effects of BCP-LP on rat NVU damage after SAH. The results demonstrated that BCP-LP treatment improved neurological function disorder, balance ability and cerebral blood perfusion in rats. Brain edema detection and blood-brain barrier permeability detection revealed that BCP-LP could reduce brain edema and promote repairment of blood-brain barrier after SAH. Using the western blot experiments, we demonstrated that BCP-LP attenuated the loss of tight junction proteins Occludin and Zonula occludens-1, inhibit the high expression of VEGFR-2 and GFAP, and promote the repair of laminin. These results demonstrate the protective effect BCP-LP exert in the NVU after SAH in rats, and supports the use of BCP-LP for future study and therapy of SAH.

Lipid-based nanodelivery approaches for dopamine-replacement therapies in Parkinson's disease: From preclinical to translational studies

The incidence of Parkinson's disease (PD), the second most common neurodegenerative disorder, has increased exponentially as the global population continues to age. Although the etiological factors contributing to PD remain uncertain, its average incidence rate is reported to be 1% of the global population older than 60 years. PD is primarily characterized by the progressive loss of dopaminergic (DAergic) neurons and/or associated neuronal networks and the subsequent depletion of dopamine (DA) levels in the brain. Thus, DA or levodopa (l-dopa), a precursor of DA, represent cardinal targets for both idiopathic and symptomatic PD therapeutics. While several therapeutic strategies have been investigated over the past decade for their abilities to curb the progression of PD, an effective cure for PD is currently unavailable. Even DA replacement therapy, an effective PD therapeutic strategy that provides an exogenous supply of DA or l-dopa, has been hindered by severe challenges, such as a poor capacity to bypass the blood-brain barrier and inadequate bioavailability. Nevertheless, with recent advances in nanotechnology, several drug delivery systems have been developed to bypass the barriers associated with central nervous system therapeutics. In here, we sought to describe the adapted lipid-based nanodrug delivery systems used in the field of PD therapeutics and their recent advances, with a particular focus placed on DA replacement therapies. This work initially explores the background of PD; offers descriptions of the most recent molecular targets; currently available clinical medications/limitations; an overview of several lipid-based PD nanotherapeutics, functionalized nanoparticles, and technical aspects in brain delivery; and, finally, presents future perspectives to enhance the use of nanotherapeutics in PD treatment.

Design of novel proliposome formulation for antioxidant peptide, glutathione with enhanced oral bioavailability and stability

To develop proliposome formulations to improve the oral bioavailability of l-glutathione (GSH), GSH-loaded proliposomes were prepared using the granule method. Mannitol was selected as an effective excipient to achieve the desired particle size, entrapment efficiency (EE), and solubility for oral delivery of the final formulation. To evaluate the effect of surface charge of proliposomes on the oral bioavailability of GSH, negative (F1-F4) and positive proliposomes (F5-F9) were prepared. Particle size of F1 and F5 was 167.8 ± 0.9 and 175.9 ± 2.0 nm, and zeta potential of F1 and F5 was -8.1 ± 0.7 and 21.1 ± 2.0 mV, respectively. Encapsulation efficiency of F1 and F5 was 58.6% and 54.7%, respectively. Considering their particle size, zeta potential, and EE, the proliposomes F1 and F5 were adopted as the optimal formulations for further experiments. Solid state characterization of the proliposomes confirmed lipid coating on the surface of mannitol. The release of GSH from F1 and F5 formulations was prolonged until 24 h and pH independent. The total antioxidant capacity of GSH was concentration-dependent and maintained after formulation of GSH proliposomes. Circular dichroism spectroscopy confirmed that the molecular structure of GSH was maintained in the proliposome formulations. GSH proliposomes exhibited no significant changes in particle size and zeta potential for 4 weeks. An oral bioavailability study in rats revealed that F5 exhibited 1.05-, 1.08-, and 1.11-fold higher bioavailability than F1, commercial capsule formulation, and pure GSH, respectively. In conclusion, the prepared GSH proliposomes enhanced the poor bioavailability of GSH and prolonged its duration of action.

Impact of Supplementary Amino Acids, Micronutrients, and Overall Diet on Glutathione Homeostasis

Glutathione (GSH) is a critical endogenous antioxidant found in all eukaryotic cells. Higher GSH concentrations protect against cellular damage, tissue degeneration, and disease progression in various models, so there is considerable interest in developing interventions that augment GSH biosynthesis. Oral GSH supplementation is not the most efficient option due to the enzymatic degradation of ingested GSH within the intestine by γ-glutamyltransferase, but supplementation of its component amino acids-cysteine, glycine, and glutamate-enhances tissue GSH synthesis. Furthermore, supplementation with some non-precursor amino acids and micronutrients appears to influence the redox status of GSH and related antioxidants, such as vitamins C and E, lowering systemic oxidative stress and slowing the rate of tissue deterioration. In this review, the effects of oral supplementation of amino acids and micronutrients on GSH metabolism are evaluated. And since specific dietary patterns and diets are being prescribed as first-line therapeutics for conditions such as hypertension and diabetes, the impact of overall diets on GSH homeostasis is also assessed.

Pharmacological activation of autophagy favors the clearing of intracellular aggregates of misfolded prion protein peptide to prevent neuronal death

According to the “gain-of-toxicity mechanism”, neuronal loss during cerebral proteinopathies is caused by accumulation of aggregation-prone conformers of misfolded cellular proteins, although it is still debated which aggregation state actually corresponds to the neurotoxic entity. Autophagy, originally described as a variant of programmed cell death, is now emerging as a crucial mechanism for cell survival in response to a variety of cell stressors, including nutrient deprivation, damage of cytoplasmic organelles, or accumulation of misfolded proteins. Impairment of autophagic flux in neurons often associates with neurodegeneration during cerebral amyloidosis, suggesting a role in clearing neurons from aggregation-prone misfolded proteins. Thus, autophagy may represent a target for innovative therapies. In this work, we show that alterations of autophagy progression occur in neurons following in vitro exposure to the amyloidogenic and neurotoxic prion protein-derived peptide PrP90-231. We report that the increase of autophagic flux represents a strategy adopted by neurons to survive the intracellular accumulation of misfolded PrP90-231. In particular, PrP90-231 internalization in A1 murine mesencephalic neurons occurs in acidic structures, showing electron microscopy hallmarks of autophagosomes and autophagolysosomes. However, these structures do not undergo resolution and accumulate in cytosol, suggesting that, in the presence of PrP90-231, autophagy is activated but its progression is impaired; the inability to clear PrP90-231 via autophagy induces cytotoxicity, causing impairment of lysosomal integrity and cytosolic diffusion of hydrolytic enzymes. Conversely, the induction of autophagy by pharmacological  blockade of mTOR kinase or trophic factor deprivation restored autophagy resolution, reducing intracellular PrP90-231 accumulation and neuronal death. Taken together, these data indicate that PrP90-231 internalization induces an autophagic defensive response in A1 neurons, although incomplete and insufficient to grant survival; the pharmacological enhancement of this process exerts neuroprotection favoring the clearing of the internalized peptide and could represents a promising neuroprotective tool for neurodegenerative proteinopathies.

Redox-based therapeutics in neurodegenerative disease

This review describes recent developments in the search for effective therapeutic agents that target redox homeostasis in neurodegenerative disease. The disruption to thiol redox homeostasis in Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and multiple sclerosis is discussed, together with the experimental strategies that are aimed at preventing, or at least minimizing, oxidative damage in these diseases. Particular attention is given to the potential of increasing antioxidant capacity by targeting the Nrf2 pathway, the development of inhibitors of NADPH oxidases that are likely candidates for clinical use, together with strategies to reduce nitrosative stress and mitochondrial dysfunction. We describe the shortcomings of compounds that hinder their progression to the clinic and evaluate likely avenues for future research.

LINKED ARTICLES

This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc.

Fabrication of basil seed gum nanoparticles as a novel oral delivery system of glutathione

Plant derived polymers like mucilage have evoked great attention in the field of functional food ingredient delivery. The objective of this study was to evaluate the potential of basil seed gum nanoparticles (BSG NPs) as an oral delivery system for glutathione (GSH). BSG NPs (1-0.25mgml^-1) were fabricated by ion gelling technique and calcium was used as a cross-linking agent (0.7-0.3mgml^-1). The results showed that BSG NPs (298-595nm) have spherical shape and the relative viscosity revealed that the possibility of agglomeration of BSG NPs is low. The interaction between BSG and GSH was confirmed by FTIR and DSC studies. Entrapment and loading efficiency of BSG-GSH nanoparticles were in the range of 6.5-43% and 7-13%, respectively. GSH release in gastrointestinal environment showed release speed in pH 1.2 was lower in compared with pH 6.8. As a result, smaller amounts of GSH will be destroyed in the stomach during digestion time.

Efficient GSH delivery using PAMAM-GSH into MPP-induced PC12 cellular model for Parkinson's disease

Glutathione (GSH) depletion has been an important contributor to the dysfunction of dopamine neurons. Polyamidoamine-GSH (PAMAM-GSH) was synthesized and the delivery effect of GSH into PC12 cells was tested. MTT assessment for cytotoxicity and reactive oxygen species (ROS) as well as nitrite oxide (NO) and intracelluar superoxide dismutase (SOD) detection for antioxidative ability were performed. Furthermore, the antiapoptotic ability was analysed by assessing caspase-3, JNK1/2 and Erk1/2 expression. Our data indicated that PAMAM-GSH is an effective agent to replenish GSH into PC12 cells. PAMAM-GSH developed its antioxidative and protective ability for 1-methyl-4-phenylpyridinium (MPP)-induced PC12 cells by reducing the intracellular levels of ROS and SOD activity as well as decreasing the release of NO. Meanwhile, PAMAM-GSH could inhibit caspase-3 activation and might show its antiapoptotic ability to MPP-induced PC12 cells through JNK2/Erk1/2 pathway. In summary, these studies suggest that PAMAM-GSH conjugate has an intrinsic ability to penetrate PC12 cells and deliver GSH into these cells which may provide a new strategy for clinical applications in the treatment of Parkinson’s disease.

Drug Delivery Systems for Imaging and Therapy of Parkinson's Disease

BACKGROUND

Although a variety of therapeutic approaches are available for the treatment of Parkinson's disease, challenges limit effective therapy. Among these challenges are delivery of drugs through the blood brain barier to the target brain tissue and the side effects observed during long term administration of antiparkinsonian drugs. The use of drug delivery systems such as liposomes, niosomes, micelles, nanoparticles, nanocapsules, gold nanoparticles, microspheres, microcapsules, nanobubbles, microbubbles and dendrimers is being investigated for diagnosis and therapy.

METHODS

This review focuses on formulation, development and advantages of nanosized drug delivery systems which can penetrate the central nervous system for the therapy and/or diagnosis of PD, and highlights future nanotechnological approaches.

RESULTS

It is esential to deliver a sufficient amount of either therapeutic or radiocontrast agents to the brain in order to provide the best possible efficacy or imaging without undesired degradation of the agent. Current treatments focus on motor symptoms, but these treatments generally do not deal with modifying the course of Parkinson's disease. Beyond pharmacological therapy, the identification of abnormal proteins such as α -synuclein, parkin or leucine-rich repeat serine/threonine protein kinase 2 could represent promising alternative targets for molecular imaging and therapy of Parkinson's disease.

CONCLUSION

Nanotechnology and nanosized drug delivery systems are being investigated intensely and could have potential effect for Parkinson's disease. The improvement of drug delivery systems could dramatically enhance the effectiveness of Parkinson's Disease therapy and reduce its side effects.

An elucidation of neutrophil functions against Mycobacterium tuberculosis infection

We characterized the functions of neutrophils in response to Mycobacterium tuberculosis (M. tb) infection, with particular reference to glutathione (GSH). We examined the effects of GSH in improving the ability of neutrophils to control intracellular M. tb infection. Our findings indicate that increasing the intracellular levels of GSH with a liposomal formulation of GSH (L-GSH) resulted in reduction in the levels of free radicals and increased acidification of M. tb containing phagosomes leading to the inhibition in the growth of M. tb. This inhibitory mechanism is dependent on the presence of TNF-α and IL-6. Our studies demonstrate a novel regulatory mechanism adapted by the neutrophils to control M. tb infection.

Glutathione metabolism and Parkinson's disease

It has been established that oxidative stress, defined as the condition in which the sum of free radicals in a cell exceeds the antioxidant capacity of the cell, contributes to the pathogenesis of Parkinson disease. Glutathione is a ubiquitous thiol tripeptide that acts alone or in concert with enzymes within cells to reduce superoxide radicals, hydroxyl radicals, and peroxynitrites. In this review, we examine the synthesis, metabolism, and functional interactions of glutathione and discuss how these relate to the protection of dopaminergic neurons from oxidative damage and its therapeutic potential in Parkinson disease.

S-Nitrosylation of parkin as a novel regulator of p53-mediated neuronal cell death in sporadic Parkinson's disease

Background

Mutations in the gene encoding parkin, a neuroprotective protein with dual functions as an E3 ubiquitin ligase and transcriptional repressor of p53, are linked to familial forms of Parkinson’s disease (PD). We hypothesized that oxidative posttranslational modification of parkin by environmental toxins may contribute to sporadic PD.

Results

We first demonstrated that S-nitrosylation of parkin decreased its activity as a repressor of p53 gene expression, leading to upregulation of p53. Chromatin immunoprecipitation as well as gel-shift assays showed that parkin bound to the p53 promoter, and this binding was inhibited by S-nitrosylation of parkin. Additionally, nitrosative stress induced apoptosis in cells expressing parkin, and this death was, at least in part, dependent upon p53. In primary mesencephalic cultures, pesticide-induced apoptosis was prevented by inhibition of nitric oxide synthase (NOS). In a mouse model of pesticide-induced PD, both S-nitrosylated (SNO-)parkin and p53 protein levels were increased, while administration of a NOS inhibitor mitigated neuronal death in these mice. Moreover, the levels of SNO-parkin and p53 were simultaneously elevated in postmortem human PD brain compared to controls.

Conclusions

Taken together, our data indicate that S-nitrosylation of parkin, leading to p53-mediated neuronal cell death, contributes to the pathophysiology of sporadic PD.

A review of the mechanism of injury and treatment approaches for illness resulting from exposure to water-damaged buildings, mold, and mycotoxins

Physicians are increasingly being asked to diagnose and treat people made ill by exposure to water-damaged environments, mold, and mycotoxins. In addition to avoidance of further exposure to these environments and to items contaminated by these environments, a number of approaches have been used to help persons affected by exposure to restore their health. Illness results from a combination of factors present in water-damaged indoor environments including, mold spores and hyphal fragments, mycotoxins, bacteria, bacterial endotoxins, and cell wall components as well as other factors. Mechanisms of illness include inflammation, oxidative stress, toxicity, infection, allergy, and irritant effects of exposure. This paper reviews the scientific literature as it relates to commonly used treatments such as glutathione, antioxidants, antifungals, and sequestering agents such as Cholestyramine, charcoal, clay and chlorella, antioxidants, probiotics, and induced sweating.

Chelation: harnessing and enhancing heavy metal detoxification--a review

Toxic metals such as arsenic, cadmium, lead, and mercury are ubiquitous, have no beneficial role in human homeostasis, and contribute to noncommunicable chronic diseases. While novel drug targets for chronic disease are eagerly sought, potentially helpful agents that aid in detoxification of toxic elements, chelators, have largely been restricted to overt acute poisoning. Chelation, that is multiple coordination bonds between organic molecules and metals, is very common in the body and at the heart of enzymes with a metal cofactor such as copper or zinc. Peptides glutathione and metallothionein chelate both essential and toxic elements as they are sequestered, transported, and excreted. Enhancing natural chelation detoxification pathways, as well as use of pharmaceutical chelators against heavy metals are reviewed. Historical adverse outcomes with chelators, lessons learned in the art of using them, and successes using chelation to ameliorate renal, cardiovascular, and neurological conditions highlight the need for renewed attention to simple, safe, inexpensive interventions that offer potential to stem the tide of debilitating, expensive chronic disease.

Glutathione supplementation improves macrophage functions in HIV

In this study, we determined the effects of glutathione (GSH)-enhancing agents in restoring the levels of GSH in isolated macrophages from individuals with HIV infection thereby resulting in improved control of Mycobacterium tuberculosis. Our results indicate that treatment with N-acetyl cysteine or a liposomal formulation of glutathione (lGSH) resulted in replenishment of reduced also known as free GSH (rGSH), and correlated with a decrease in the intracellular growth of M. tuberculosis. Finally, we observed differences in the amount of the catalytic subunit of glutamine-cysteine ligase (GCLC), glutathione synthase, and glutathione reductase present in macrophages derived from healthy and HIV-infected individuals. These changes correlated with changes in free radicals as well as rGSH levels. Our results indicate that HIV infection leads to increased production of free radicals and decreased production of GCLC resulting in depletion of rGSH and this may lead, in part, to the loss of innate immune function observed in HIV patients. These findings represent a novel mechanism for control of M. tuberculosis infection, and a possible supplement to current HIV treatments.

Rafts, Nanoparticles and Neural Disease

This review examines the role of membrane rafts in neural disease as a rationale for drug targeting utilizing lipid-based nanoparticles. The article begins with an overview of methodological issues involving the existence, sizes, and lifetimes of rafts, and then examines raft function in the etiologies of three major neural diseases-epilepsy, Parkinson's disease, and Alzheimer's disease-selected as promising candidates for raft-based therapeutics. Raft-targeting drug delivery systems involving liposomes and solid lipid nanoparticles are then examined in detail.

Recent advances in the treatment of neurodegenerative diseases based on GSH delivery systems

Neurodegenerative diseases, such as Parkinson's disease (PD) and Alzheimer's disease(AD), are a group of pathologies characterized by a progressive and specific loss of certain brain cell populations. Oxidative stress, mitochondrial dysfunction, and apoptosis play interrelated roles in these disorders. It is well documented that free radical oxidative damage, particularly on neuronal lipids, proteins, DNA, and RNA, is extensive in PD and AD brains. Moreover, alterations of glutathione (GSH) metabolism in brain have been implicated in oxidative stress and neurodegenerative diseases. As a consequence, the reduced GSH levels observed in these pathologies have stimulated a number of researchers to find new potential approaches for maintaining or restoring GSH levels. Unfortunately, GSH delivery to the central nervous system (CNS) is limited due to a poor stability and low bioavailability. Medicinal-chemistry- and technology-based approaches are commonly used to improve physicochemical, biopharmaceutical, and drug delivery properties of therapeutic agents. This paper will focus primarily on these approaches used in order to replenish intracellular GSH levels, which are reduced in neurodegenerative diseases. Here, we discuss the beneficial properties of these approaches and their potential implications for the future treatment of patients suffering from neurodegenerative diseases, and more specifically from PD and AD.

Liposomes for Targeted Delivery of Active Agents against Neurodegenerative Diseases (Alzheimer's Disease and Parkinson's Disease)

Neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease represent a huge unmet medical need. The prevalence of both diseases is increasing, but the efficacy of treatment is still very limited due to various factors including the blood brain barrier (BBB). Drug delivery to the brain remains the major challenge for the treatment of all neurodegenerative diseases because of the numerous protective barriers surrounding the central nervous system. New therapeutic drugs that cross the BBB are critically needed for treatment of many brain diseases. One of the significant factors on neurotherapeutics is the constraint of the blood brain barrier and the drug release kinetics that cause peripheral serious side effects. Contrary to common belief, neurodegenerative and neurological diseases may be multisystemic in nature, and this presents numerous difficulties for their potential treatment. Overall, the aim of this paper is to summarize the last findings and news related to liposome technology in the treatment of neurodegenerative diseases and demonstrate the potential of this technology for the development of novel therapeutics and the possible applications of liposomes in the two most widespread neurodegenerative diseases, Alzheimer's disease and Parkinson's disease.

Liposomal Antioxidants for Protection against Oxidant-Induced Damage

Reactive oxygen species (ROS), including superoxide anion, hydrogen peroxide, and hydroxyl radical, can be formed as normal products of aerobic metabolism and can be produced at elevated rates under pathophysiological conditions. Overproduction and/or insufficient removal of ROS result in significant damage to cell structure and functions. In vitro studies showed that antioxidants, when applied directly and at relatively high concentrations to cellular systems, are effective in conferring protection against the damaging actions of ROS, but results from animal and human studies showed that several antioxidants provide only modest benefit and even possible harm. Antioxidants have yet to be rendered into reliable and safe therapies because of their poor solubility, inability to cross membrane barriers, extensive first-pass metabolism, and rapid clearance from cells. There is considerable interest towards the development of drug-delivery systems that would result in the selective delivery of antioxidants to tissues in sufficient concentrations to ameliorate oxidant-induced tissue injuries. Liposomes are biocompatible, biodegradable, and nontoxic artificial phospholipid vesicles that offer the possibility of carrying hydrophilic, hydrophobic, and amphiphilic molecules. This paper focus on the use of liposomes for the delivery of antioxidants in the prevention or treatment of pathological conditions related to oxidative stress.