Effect of NAC treatment and physical activity on neuroinflammation in subchronic Parkinsonism; is physical activity essential?

BACKGROUND: Neuroprotective strategies are becoming relevant to slow down dopaminergic cell death and inflammatory processes related to the progressive neurodegeneration in Parkinson's disease (PD). Interestingly, among others, physical activity (PA) or anti-oxidant agents (such as N-acetyl-L-cysteine, NAC) are common therapeutic strategies. Therefore, this study aims to analyze if there is a synergistic effect of physical activity along with NAC treatment on dopaminergic degeneration and neuroinflammatory response in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinsonism model after subchronic intoxication. METHODS: To ascertain this possibility, 48 8-week-old male mice (C57BL/6 strain) were used. Twenty four of them were placed individually in cages where voluntary physical activity was automatically monitored during 30 days and were divided into groups: (i) control; (ii) NAC; (iii) MPTP, and (iv) MPTP+NAC. The other 24 mice were divided into the same four groups but without physical activity. RESULTS: The data collected during the treatment period showed that there was an overall increase in the total running distance in all groups under physical activity, including Parkinsonian animals. However, the monitoring data per day showed that the activity routine by MPTP and MPTP+NAC groups was disrupted by alterations in the circardian rhythm because of MPTP intoxication. Results from post-mortem studies in the substantia nigra pars compacta (SNpc) showed significant decrease in the number of TH+ cells in all MPTP groups. Moreover, TH+ expression in the striatum was significantly decreased in all MPTP groups. Thus, PA + NAC treatment do not protect dopaminergic neurons against a subchronic intoxication of MPTP. Regarding glial response, the results obtained from microglial analysis do not show significant increase in the number of Iba-1+ cell in MPTP+NAC and MPTP+PA + NAC. In the striatum, a significant decrease is observed only in the MPTP+NAC group compared with that of the MPTP group. The microglial results are reinforced by those obtained from the analysis of astroglial response, in which a decrease in the expression of GFAP+ cells are observed in MPTP+NAC and MPTP+PA + NAC compared with MPTP groups both in the SNpc and in the striatum. Finally, from the study of the astroglial response by the co-localization of GFAP/S100b, we described some expression patterns observed based on the severity of the damage produced by the MPTP intoxication in the different treated groups. CONCLUSIONS: These results suggest that the combination of physical activity with an anti-oxidant agent does not have a synergistic neuroprotective effect in the nigrostriatal pathway. Our results show a potential positive effect, only due to NAC treatment, on the neuroinflammatory response after subchronic MPTP intoxication. Thus, physical activity is not essential, under these conditions. However, we believe that physical activity, used for therapeutic purposes, has a beneficial long-term effect. In this line, these results open the door to design longer studies to demonstrate its promising effect as neuroprotective strategy.

Disease Modification in Parkinson's Disease: Current Approaches, Challenges, and Future Considerations.

The greatest unmet therapeutic need in Parkinson's disease is the development of treatment that slows the relentless progression of the neurodegenerative process. The concept of "disease modification" encompasses intervention types ranging from those designed to slow the underlying degeneration to treatments directed at regenerating or replacing lost neurons. To date all attempts to develop effective disease-modifying therapy have failed. Many reasons have been proposed for these failures including our rudimentary understanding of disease pathogenesis and the assumption that each targeted mechanisms of disease apply to most patients with the same clinical diagnosis. Here we review all aspects of this broad field including general concepts and past challenges followed by a discussion of treatment approaches under the following 4 categories: (1) α-synuclein, (2) pathogenic mechanisms distinct from α-synuclein (most also potentially triggered by α-synuclein toxicity), (3) non-SNCA genetic subtypes of "PD," and (4) possible disease-modifying interventions not directly influencing the underlying PD pathobiology. We emphasize treatments that are currently under active clinical development and highlight a wide range of important outstanding questions and concerns that will need to be considered to advance the field of disease modification in PD. Critically, it is unknown whether the dysfunctional molecular pathways/organelles amenable to modification occur in a sequential fashion across most clinically affected individuals or manifest differentially in independent molecular subtypes of PD. It is possible that there is no "order of disruption" applicable to most patients but, rather, "type of disruption" applicable to subtypes dependent on unknown factors, including genetic variability and other causes for heterogeneity in PD. Knowing when (early vs late), which (eg, synaptic transmission, endosomal sorting and maturation, lysosomal degradation, mitochondrial biogenesis), and in whom (PD subtype) specific disrupted cell pathways are truly pathogenic versus compensatory or even protective, will be important in considering the use of single or combined ("cocktails") putative disease-modifying therapies to selectively target these processes. Beyond the current phase 2 or 3 studies underway evaluating treatments directed at oxidative stress (inosine), cytosolic Ca2+ (isradipine), iron (deferiprone), and extracellular α-synuclein (passive immunization), and upcoming trials of interventions affecting c-Abl, glucagon-like peptide-1, and glucocerebrosidase, it might be argued that further trials in populations not enriched for the targeted pathogenic process are doomed to repeat the failures of the past. © 2018 International Parkinson and Movement Disorder Society.

AMP-activated protein kinase-dependent induction of autophagy by erythropoietin protects against spinal cord injury in rats.

AIMS: Autophagy has been regarded as a promising therapeutic target for spinal cord injury (SCI). Erythropoietin (EPO) has been demonstrated to exhibit neuroprotective effects in the central nervous system (CNS); however, the molecular mechanisms of its protection against SCI remain unknown. This study aims to investigate whether the neuroprotective effects of EPO on SCI are mediated by autophagy via AMP-activated protein kinase (AMPK) signaling pathways. METHODS: Functional assessment and Nissl staining were used to investigate the effects of EPO on SCI. Expressions of proteins were detected by Western blot and immunohistochemistry. RESULTS: Treatment with EPO significantly reduced the loss of motor neurons and improved the functional recovery following SCI. Erythropoietin significantly enhanced the SCI-induced autophagy through activating AMPK and inactivating mTOR signaling. The inhibitor of AMPK, compound C, could block the EPO-induced autophagy and beneficial action on SCI, whereas the activator of AMPK, metformin, could mimic the effects of EPO. In the in vitro studies, EPO enhanced the hypoxia-induced autophagy in an AMPK-dependent manner. CONCLUSIONS: The AMPK-dependent induction of autophagy contributes to the neuroprotection of EPO on SCI.

Biological activities of non-enzymatic oxygenated metabolites of polyunsaturated fatty acids (NEO-PUFAs) derived from EPA and DHA: New anti-arrhythmic compounds?

ω3 Polyunsaturated fatty acids (ω3 PUFAs) have several biological properties including anti-arrhythmic effects. However, there are some evidences that it is not solely ω3 PUFAs per se that are biologically active but the non-enzymatic oxygenated metabolites of polyunsaturated fatty acids (NEO-PUFAs) like isoprostanes and neuroprostanes. Recent question arises how these molecules take part in physiological homeostasis, show biological bioactivities and anti-inflammatory properties. Furthermore, they are involved in the circulations of childbirth, by inducing the closure of the ductus arteriosus. In addition, oxidative stress which can be beneficial for the heart in given environmental conditions such as the presence of ω3 PUFAs on the site of the stress and the signaling pathways involved are also explained in this review.

Long noncoding RNA Malat1 is a potent autophagy inducer protecting brain microvascular endothelial cells against oxygen-glucose deprivation/reoxygenation-induced injury by sponging miR-26b and upregulating ULK2 expression.

Brain microvascular endothelial cell (BMEC) injury induced by ischemia-reperfusion (I/R) is the initial stage of blood-brain barrier (BBB) disruption, which results in a poor prognosis in ischemic stroke patients. Autophagy has been shown to have protective effects on BMECs against cerebral ischemic insults. However, molecular mechanism of BMEC autophagy during I/R is unclear. Long noncoding RNAs (lncRNAs) are emerging as new factors involved in cell autophagy. LncRNA Malat1 is one of the most highly upregulated I/R or OGD/R-responsive endothelial lncRNA and plays a protective role in BMECs against cerebral ischemic insults. Oxygen-glucose deprivation/reoxygenation (OGD/R) is used to mimic I/R injury in vitro. Based on these findings, we hypothesized that Malat1 might play a protective role by enhancing BMEC autophagy. We performed GFP-LC3 puncta formation, LC3 conversion, p62 expression, and cell death assays, and the results were consistent with our hypothesis that Malat1 promoted BMEC autophagy and survival under OGD/R condition. We further explored the molecular mechanisms by which Malat1 exerted regulatory effects, and found that Malat1 served as an endogenous sponge to downregulate miR-26b expression by binding directly to miR-26b. Furthermore, Malat1 overturned the inhibitory effect of miR-26b on BMEC autophagy and survival, which involved in promoting the expression of miR-26b target ULK2. Collectively, our study illuminated a new Malat1-miR-26b-ULK2 regulatory axis in which Malat1 served as a competing endogenous RNA by sponging miR-26b and upregulating ULK2 expression, thereby promoting BMEC autophagy and survival under OGD/R condition.

Comparison of sensory tests and neuronal quantity of peripheral nerves between streptozotocin (STZ)-induced diabetic rats and paclitaxel (PAC)-treated rats.

Although diabetic peripheral neuropathy (DPN) and chemotherapy-induced peripheral neuropathy (CIPN) are different disease entities, they share similar neuropathic symptoms that impede quality of life for these patients. Despite having very similar downstream effects, there have been no direct comparisons between DPN and CIPN with respect to symptom severity and therapeutic responses. We compared peripheral nerve damage due to hyperglycemia with that caused by paclitaxel (PAC) treatment as represented by biochemical parameters, diverse sensory tests, and immunohistochemistry of cutaneous and sciatic nerves. The therapeutic effects of alpha-lipoic acid and DA-9801 were also compared in the two models. Animals were divided into seven groups (n = 7-10) as follows: normal, diabetes (DM), DM + alpha-lipoic acid 100 mg/kg (ALA), DM + DA-9801 (100 mg/kg), paclitaxel-treated rat (PAC), PAC + ALA (100 mg/kg), and PAC + DA-9801 (100 mg/kg). The sensory thresholds of animals to mechanical, heat, and pressure stimuli were altered by both hyperglycemia and PAC when compared with controls, and the responses to sensory tests were different between both groups. There were no significant differences in the biochemical markers of blood glutathione between DM and PAC groups (p > .05). Quantitative comparisons of peripheral nerves by intraepidermal nerve fiber density (IENFD) analysis indicated that the DM and PAC groups were similar (6.18 ± 1.03 vs. 5.01 ± 2.57). IENFD was significantly improved after ALA and DA-9801 treatment in diabetic animals (7.6 ± 1.28, 7.7 ± 1.28, respectively, p < .05) but did not reach significance in the PAC-treated groups (6.05 ± 1.76, 5.66 ± 1.26, respectively, p > .05). Sciatic nerves were less damaged in the PAC-treated groups compared with the DM groups with respect to axonal diameter and area (8.60 ± 1.14 µm vs. 6.66 ± 1.07 µm, and 59.04 ± 15.16 µm2 vs. 35.71 ± 11.2 µm2, respectively, p < .05). Based on these results, the neuropathic manifestation and therapeutic responses of DPN may be different from other peripheral neuropathies. Therefore, specific pathogenic consideration according to peripheral neuropathy classification in addition to common treatments needs to be developed for management strategies of peripheral neuropathies.

Neuroprotective and anti-inflammatory effects of morin in a murine model of Parkinson's disease.

Parkinson's disease (PD) is one of the most common neurodegenerative disorders and is characterized by loss of dopaminergic neurons in the substantia nigra (SN). Although the causes of PD are not understood, evidence suggests that oxidative stress, mitochondrial dysfunction, and inflammation are associated with its pathogenesis. Morin (3,5,7,2',4'-pentahydroxyflavone) is a flavonol found in wine and many herbs and fruits. Previous studies have suggested that morin prevents oxidative damage and inflammation and ameliorates mitochondrial dysfunction. The present study describes the neuroprotective effects of morin in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD, and we report the results of our investigation into its neuroprotective mechanism in primary neurons and astrocytes. In the mouse model, morin pretreatment ameliorated motor dysfunction, protected against dopaminergic neuronal losses in SN and striatum, and alleviated MPTP-induced astrocyte activation. In vitro studies revealed that morin protected primary cultured neurons against 1-methyl-4-phenylpyridine (MPP(+) )-mediated reactive oxygen species production and mitochondrial membrane potential (MMP) disruption. In addition, morin effectively reduced MPP(+) -induced astroglial activation and nuclear translocation of nuclear factor-κB in primary cultured astrocytes. These results indicate that morin acts via multiple neuroprotective mechanisms in our mouse model and suggest that morin be viewed as a potential treatment and preventative for PD. © 2016 Wiley Periodicals, Inc.

AVN-101: A Multi-Target Drug Candidate for the Treatment of CNS Disorders.

Lack of efficacy of many new highly selective and specific drug candidates in treating diseases with poorly understood or complex etiology, as are many of central nervous system (CNS) diseases, encouraged an idea of developing multi-modal (multi-targeted) drugs. In this manuscript, we describe molecular pharmacology, in vitro ADME, pharmacokinetics in animals and humans (part of the Phase I clinical studies), bio-distribution, bioavailability, in vivo efficacy, and safety profile of the multimodal drug candidate, AVN-101. We have carried out development of a next generation drug candidate with a multi-targeted mechanism of action, to treat CNS disorders. AVN-101 is a very potent 5-HT7 receptor antagonist (Ki = 153 pM), with slightly lesser potency toward 5-HT6, 5-HT2A, and 5HT-2C receptors (Ki = 1.2-2.0 nM). AVN-101 also exhibits a rather high affinity toward histamine H1 (Ki = 0.58 nM) and adrenergic α2A, α2B, and α2C (Ki = 0.41-3.6 nM) receptors. AVN-101 shows a good oral bioavailability and facilitated brain-blood barrier permeability, low toxicity, and reasonable efficacy in animal models of CNS diseases. The Phase I clinical study indicates the AVN-101 to be well tolerated when taken orally at doses of up to 20 mg daily. It does not dramatically influence plasma and urine biochemistry, nor does it prolong QT ECG interval, thus indicating low safety concerns. The primary therapeutic area for AVN-101 to be tested in clinical trials would be Alzheimer's disease. However, due to its anxiolytic and anti-depressive activities, there is a strong rational for it to also be studied in such diseases as general anxiety disorders, depression, schizophrenia, and multiple sclerosis.

A combination of neostigmine and anisodamine protects against ischemic stroke by activating α7nAChR.

BACKGROUND: Increasing endogenous acetylcholine by neostigmine decreased the ischemic cerebral injury. The off-target action on muscarinic receptor produced a variety of adverse effects and limited the clinical application on stroke. AIM: We combined neostigmine with anisodamine and investigated the neuroprotection and mechanism. METHODS: Male Sprague-Dawley rats were subjected to middle cerebral artery occlusion. Neuroprotective action of neostigmine in combination with anisodamine at varying ratios was examined to determine the optimal combination as well as ideal therapeutic window. Potential involvement of α7 nicotinic acetylcholine receptor was examined by measuring the infarct size, the expression of proinflammatory cytokines, and the biomarkers of apoptosis in α7 nicotinic acetylcholine receptor knockout mice. A set of in vitro experiments was conducted in RAW264.7 cells to probe into potential molecular mechanisms. RESULTS: The neostigmine/anisodamine combination conferred neuroprotection. The protection was most potent at a ratio of 1:500. At such a ratio, the combination increased the binding of acetylcholine to α7 nicotinic acetylcholine receptor and reduced proinflammatory cytokines. The neuroprotection was evident only in wild-type and not in α7 nicotinic acetylcholine receptor knockout mice. The combination significantly decreased the expression of Bad and Bax, and increased Bcl-2 and Bcl-xl in α7 nicotinic acetylcholine receptor wild-type mice but not in knockout mice. The combination did not affect caspase-8, cleaved caspase-8, or caspase-12. CONCLUSIONS: Current study identified the optimal combination of neostigmine and anisodamine against ischemic stroke, and indicated that the acetylcholine-α7 nicotinic acetylcholine receptor is involved in the protective effects.

The neuroprotective actions of oestradiol and oestrogen receptors.

Hormones regulate homeostasis by communicating through the bloodstream to the body's organs, including the brain. As homeostatic regulators of brain function, some hormones exert neuroprotective actions. This is the case for the ovarian hormone 17ß-oestradiol, which signals through oestrogen receptors (ERs) that are widely distributed in the male and female brain. Recent discoveries have shown that oestradiol is not only a reproductive hormone but also a brain-derived neuroprotective factor in males and females and that ERs coordinate multiple signalling mechanisms that protect the brain from neurodegenerative diseases, affective disorders and cognitive decline.

Calcium influx and calpain activation mediate preclinical retinal neurodegeneration in autoimmune optic neuritis.

Optic neuritis is a common manifestation of multiple sclerosis, an inflammatory demyelinating disease of the CNS. Recently, the neurodegenerative component of multiple sclerosis has come under focus particularly because permanent disability in patients correlates well with neurodegeneration; and observations in both humans and multiple sclerosis animal models highlight neurodegeneration of retinal ganglion cells as an early event. After myelin oligodendrocyte glycoprotein immunization of Brown Norway rats, significant retinal ganglion cell loss precedes the onset of pathologically defined autoimmune optic neuritis. To study the role calcium and calpain activation may play in mediating early degeneration, manganese-enhanced magnetic resonance imaging was used to monitor preclinical calcium elevations in the retina and optic nerve of myelin oligodendrocyte glycoprotein-immunized Brown Norway rats. Calcium elevation correlated with an increase in calpain activation during the induction phase of optic neuritis, as revealed by increased calpain-specific cleavage of spectrin. The relevance of early calpain activation to neurodegeneration during disease induction was addressed by performing treatment studies with the calpain inhibitor calpeptin. Treatment not only reduced calpain activity but also protected retinal ganglion cells from preclinical degeneration. These data indicate that elevation of retinal calcium levels and calpain activation are early events in autoimmune optic neuritis, providing a potential therapeutic target for neuroprotection.

Preclinical assessment of ketamine.

Ketamine is used as a general anesthetic, and recent data suggest that anesthetics can cause neurodegeneration and/or neuroprotection. The precise mechanisms are not completely understood. This review is to examine the work on ketamine and to address how developmental biology may be utilized when combined with biochemical, pathological, and pharmacokinetic assessments to produce a bridging model that may decrease the uncertainty in extrapolating preclinical data to human conditions. Advantages of using preclinical models to study critical issues related to ketamine anesthesia have been described. These include the relationships between ketamine-induced neurotoxicity/protection and the preclinical models/approaches in elucidating mechanisms associated with ketamine exposure. The discussions focus on the following: (1) the doses and time-course over which ketamine is associated with damage to, or protection of, neural cells, (2) how ketamine directs or signals neural cells to undergo apoptosis or necrosis, (3) how such exposures can trigger mitochondrial dysfunction, (4) how antioxidants and knockdowns of specific transcription modulators or receptors affect neurotoxicity induced by ketamine, and (5) whether the potential neural damage can be monitored after ketamine exposure in living animals using positron emission tomography.

Estrogen receptors and ischemic neuroprotection: who, what, where, and when?

Estrogens, particularly 17ß-estradiol (E2), are powerful neuroprotective agents in animal models of cerebral ischemia. Loss of endogenous E2 in women at menopause or after surgical oopherectomy leads to an increase risk of stroke, neurodegenerative disease, and cognitive decline. However, several clinical trials found detrimental effects of E2 therapy after menopause, including increased stroke risk and dementia. Recent animal and human studies now support the "critical period" hypothesis for E2 neuroprotection whereby E2 therapy must begin soon after the loss of endogenous E2 production to have a beneficial effect. Although a wide array of mechanisms has been proposed for estradiol (E2)-dependent neuroprotection in cerebral ischemia and neurodegenerative disease, most of these mechanisms involve interactions of E2 with one of its cognate receptors, estrogen receptor alpha (ERα), estrogen receptor beta (ERß), or the G protein-coupled estrogen receptor (GPER). However, these receptors are not uniformly distributed throughout the brain, across different cell types, and within cellular compartments. Such differences likely play a role in the ability of E2 and ER selective ligands to protect the brain from ischemia. This review examines the changes in ER expression and location that may underlie the loss of E2 neuroprotection seen with aging and long-term estrogen deprivation (LTED). Recent results suggest that the loss of ERα that accompanies aging and LTED plays an important role in the loss of E2-dependent neuroprotection. This article is part of a Special Issue entitled Hormone Therapy.

Regulated hypoxia/reperfusion-dependent modulation of ERK1/2, cPLA2, and Bcl-2/Bax: a potential mechanism of neuroprotective effect of penehyclidine hydrochloride.

The activation of event-related kinase 1/2 (ERK1/2) and cytosolic phospholipaseA2 (cPLA2), which can aggravate hypoxia/reoxygenation (H/R) damage related to their downstream Bcl-2/Bax and Caspase-3 pathway, plays a key role in H/R. The M1 receptors could be responsible for activation of ERK1/2. Thus, it seems that the regulation of M1 receptors mediated the ERK1/2; cPLA2-mediated Bcl-2/Bax pathway may be a significant responsive signal in H/R. Penehyclidine hydrochloride (PHC) is an anticholinergic agent with high degree of selectivity for M1 and M3 receptor subtypes, it is reported that PHC has a protective effect against H/R damage. Here we hypothesize and demonstrate that PHC could downregulate the expression of pERK1/2, cPLA2, and Caspase-3, increased the ratio of Bcl-2/Bax. This study may widen the application of PHC and therapeutic agents of stroke.

Placental growth factor: a tissue modelling factor with therapeutic potentials in neurology?

Placental growth factor (PlGF) is an angiogenic factor that belongs to the vascular endothelial growth factor (VEGF) family. Besides its well known capacity to potentiate the angiogenic action of VEGF, PlGF also participates in inflammatory processes by attracting and activating monocytes; it plays therefore more specifically a role in pathological conditions. PIGF and its two receptors, VEGFR-1 and neuropilins (NRPs), are expressed in the brain and increase after experimental stroke, but their precise functions in the nervous system remain underexplored. In this review article, we summarize present knowledge on the role of PlGF in various nervous system disease processes. Given the available data, P1GF has neuroprotective and neurotrophic properties that make it an actor of considerable interest in the pathophysiology and potentially in the therapy of degenerative and traumatic brain or spinal cord diseases.

Peroxiredoxin-2 protects against 6-hydroxydopamine-induced dopaminergic neurodegeneration via attenuation of the apoptosis signal-regulating kinase (ASK1) signaling cascade.

The peroxiredoxin (PRX) family of antioxidant enzymes helps maintain the intracellular reducing milieu and suppresses apoptosis in non-neuronal cells. However, whether PRX can inhibit neuronal apoptosis through specific signaling mechanisms remains poorly understood. Induction of PRX2, the most abundant neuronal PRX, occurs in Parkinson's disease (PD) patient brains, but its functional impact is unclear. In the present study, we used the dopaminergic (DA) toxin 6-hydroxydopamine (6-OHDA) to model PD and explore the protective effect and mechanisms of PRX on DA neurons. Of the 2-cysteine PRXs that were tested in MN9D DA neurons, endogenous PRX2 was most beneficial to cell survival. Lentivirus-mediated PRX2 overexpression conferred marked in vitro and in vivo neuroprotection against 6-OHDA toxicity in DA neurons, and preserved motor functions involving the dopamine system in mouse. In addition to its role as an antioxidant enzyme, PRX2 exhibited anti-apoptotic effects in DA neurons via suppression of apoptosis signal-regulating kinase (ASK1)-dependent activation of the c-Jun N-terminal kinase/c-Jun and p38 pro-death pathways, which are also activated in DA neurons of postmortem PD brains. PRX2 inhibited 6-OHDA-induced ASK1 activation by modulating the redox status of the endogenous ASK1 inhibitor thioredoxin (Trx). PRX2 overexpression maintained Trx in a reduced state by inhibiting the cysteine thiol-disulfide exchange, thereby preventing its dissociation from ASK1. This study describes a previously undefined mechanism by which redox-sensitive molecules signal via apoptotic pathways in response to PD-relevant toxic stress in DA neurons. Our results also suggest that PRX2 and ASK1 may be potential targets for neuroprotective intervention in PD.

Oxidative insults to neurons and synapse are prevented by aged garlic extract and S-allyl-L-cysteine treatment in the neuronal culture and APP-Tg mouse model.

Alzheimer's disease (AD) is one of the most common forms of dementia in the elderly. In AD patients, ß-amyloid peptide (Aß) plaques and neurofibrillary tangles are common features observed in the CNS. Aß deposition results in the production of reactive oxygen species (ROS) leading to the hyperphosphorylation of tau that are associated with neuronal damage. Cholinesterase inhibitors and a partial NMDA receptor antagonist (memantine) have been identified as potential treatment options for AD. However, clinical studies have found that these drugs fail to prevent the disease progression. From ancient times, garlic (Allium sativum) has been used to treat several diseases. By 'aging' of garlic, some adverse reactions of garlic can be eliminated. Recent findings suggest that 'aged garlic extract' (AGE) may be a therapeutic agent for AD because of its antioxidant and Aß lowering properties. To date, the molecular properties of AGE have been sparsely studied in vitro or in vivo. The present study tested specific biochemical and molecular effects of AGE in neuronal and AD rodent models. Furthermore, we identified S-allyl-L-cysteine (SAC) as one of the most active chemicals responsible for the AGE-mediated effect(s). We observed significant neuroprotective and neurorescue properties of AGE and one of its ingredients, SAC, from ROS (H(2)O(2))-mediated insults to neuronal cells. Treatment of AGE and SAC were found to protect neuronal cells when they were independently co-treated with ROS. Furthermore, a novel neuropreservation effect of AGE was detected in that pre-treatment with AGE alone protected ∼ 80% neuronal cells from ROS-mediated damage. AGE was also found to preserve pre-synaptic protein synaptosomal associated protein of 25 kDa (SNAP25) from ROS-mediated insult. For example, treatment with 2% AGE containing diet and SAC (20 mg/kg of diet) independently increased (∼70%) levels of SNAP25 and synaptophysin in Alzheimer's amyloid precursor protein-transgenic mice, of which the latter was significantly decreased in AD. Taken together, the neuroprotective, including preservation of pre-synaptic proteins by AGE and SAC can be utilized in future drug development in AD.