Neuroprotective effect of rasagiline, a selective monoamine oxidase-B inhibitor, against closed head injury in the mouse

Chronic methamphetamine-induced neurodegeneration: Differential vulnerability of ventral tegmental area and substantia nigra pars compacta dopamine neurons

Methamphetamine (meth) increases monoamine oxidase (MAO)-dependent mitochondrial stress in substantia nigra pars compacta (SNc) axons; chronic administration produces SNc degeneration that is prevented by MAO inhibition suggesting that MAO-dependent axonal mitochondrial stress is a causal factor. To test whether meth similarly increases mitochondrial stress in ventral tegmental area (VTA) axons, we used a genetically encoded redox biosensor to assess mitochondrial stress ex vivo. Meth increased MAO-dependent mitochondrial stress in both SNc and VTA axons. However, despite having the same meth-induced stress as SNc neurons, VTA neurons were resistant to chronic meth-induced degeneration indicating that meth-induced MAO-dependent mitochondrial stress in axons was necessary but not sufficient for degeneration. To determine whether L-type Ca2+ channel-dependent stress differentiates SNc and VTA axons, as reported in the soma, the L-type Ca2+ channel activator Bay K8644 was used. Opening L-type Ca2+ channels increased axonal mitochondrial stress in SNc but not VTA axons. To first determine whether mitochondrial stress was necessary for SNc degeneration, mice were treated with the mitochondrial antioxidant mitoTEMPO. Chronic meth-induced SNc degeneration was prevented by mitoTEMPO thereby confirming the necessity of mitochondrial stress. Similar to results with the antioxidant, both MAO inhibition and L-type Ca2+ channel inhibition also prevented SNc degeneration. Taken together the presented data demonstrate that both MAO- and L-type Ca2+ channel-dependent mitochondrial stress is necessary for chronic meth-induced degeneration.

Large nest building and high marble-burying: Two compulsive-like phenotypes expressed by deer mice (Peromyscus maniculatus bairdii) and their unique response to serotoninergic and dopamine modulating intervention

This study aimed to further dissect the deer mouse (Peromyscus maniculatus bairdii) model of compulsive-like behavior with respect to two persistent-like behavioral phenotypes viz. large nest building (LNB) and high marble-burying (HMB), which may be relevant to understanding the neurobiology of different symptom dimensions in obsessive-compulsive and related disorders. Since LNB is sensitive to chronic, high dose escitalopram intervention but HMB is not, we assessed whether the two behaviors could be further distinguished based on their response to 4 weeks of uninterrupted serotoninergic intervention (i.e. escitalopram; ESC; 50 mg/kg/day), dopaminergic antagonism, i.e. flupentixol; FLU; 0.9 mg/kg/day), dopaminergic potentiation (i.e. rasagiline; RAS; 5 mg/kg/day), and their respective combinations with escitalopram (ESC/FLU and ESC/RAS). Here we show LNB to be equally responsive to chronic ESC and ESC/FLU. HMB was insensitive to either of these interventions but was responsive to ESC/RAS. Additionally, we report that scoring preoccupied interaction with marbles over several trials is an appropriate measure of compulsive-like behavioral persistence in addition to the standard marble burying test. Taken together, these data provide further evidence that LNB and HMB in deer mice have distinctive neurobiological underpinnings. Thus, the naturally occurring compulsive-like behaviors expressed by deer mice may be useful in providing a platform to test unique treatment targets for different symptom dimensions of OCD and related disorders.

Transcriptional Factors and Protein Biomarkers as Target Therapeutics in Traumatic Spinal Cord and Brain Injury

Traumatic injury to the spinal cord (SCI) and brain (TBI) are serious health problems and affect many people every year throughout the world. These devastating injuries are affecting not only patients but also their families socially as well as financially. SCI and TBI lead to neurological dysfunction besides continuous inflammation, ischemia, and necrosis followed by progressive neurodegeneration. There are well-established changes in several other processes such as gene expression as well as protein levels that are the important key factors to control the progression of these diseases. We are not yet able to collect enough knowledge on the underlying mechanisms leading to the altered gene expression profiles and protein levels in SCI and TBI. Cell loss is hastened by the induction or imbalance of pro- or anti-inflammatory expression profiles and transcription factors for cell survival after or during trauma. There is a sequence of events of dysregulation of these factors from early to late stages of trauma that opens a therapeutic window for new interventions to prevent/restrict the progression of these diseases. There has been increasing interest in the modulation of these factors for improving the patient’s quality of life by targeting both SCI and TBI. Here, we review some of the recent transcriptional factors and protein biomarkers that have been developed and discovered in the last decade in the context of targeted therapeutics for SCI and TBI patients.

A Systematic Review of Closed Head Injury Models of Mild Traumatic Brain Injury in Mice and Rats

Mild TBI (mTBI) is a significant health concern. Animal models of mTBI are essential for understanding mechanisms, and pathological outcomes, as well as to test therapeutic interventions. A variety of closed head models of mTBI that incorporate different aspects (i.e., biomechanics) of the mTBI have been reported. The aim of the current review was to compile a comprehensive list of the closed head mTBI rodent models, along with the common data elements, and outcomes, with the goal to summarize the current state of the field. Publications were identified from a search of PubMed and Web of Science and screened for eligibility following PRISMA guidelines. Articles were included that were closed head injuries in which the authors classified the injury as mild in rats or mice. Injury model and animal-specific common data elements, as well as behavioral and histological outcomes, were collected and compiled from a total of 402 articles. Our results outline the wide variety of methods used to model mTBI. We also discovered that female rodents and both young and aged animals are under-represented in experimental mTBI studies. Our findings will aid in providing context comparing the injury models and provide a starting point for the selection of the most appropriate model of mTBI to address a specific hypothesis. We believe this review will be a useful starting place for determining what has been done and what knowledge is missing in the field to reduce the burden of mTBI.

Rational Design of Novel Selective Dual-Target Inhibitors of Acetylcholinesterase and Monoamine Oxidase B as Potential Anti-Alzheimer's Disease Agents

Multifunctional agents aiming at cholinesterases (ChEs) and monoamine oxidases (MAOs) are promising therapy for Alzheimer's disease (AD). Herein, a series of novel propargylamine-modified pyrimidinylthiourea derivatives (1-4) were designed and synthesized as dual inhibitors of ChEs and MAOs with other functions against AD. Most of these derivatives inhibited ChEs and MAOs with IC₅₀ values in the micro- or nanomolar ranges. Compound 1c displayed the dual functional profile of targeting the AChE (IC₅₀ = 0.032 ± 0.007 μM) and MAO-B (IC₅₀ = 2.117 ± 0.061 μM), along with the improved blood-brain barrier (BBB) permeability, antioxidant ability, and good copper chelating property in vitro. Animal studies showed that compound 1c·HCl could inhibit the cerebral AChE/MAO-B activities and alleviate scopolamine-induced cognitive impairment in mice. Combined with good oral bioavailability ( F = 45.55%), these findings demonstrated that compound 1c may be a potent brain permeable multifunctional candidate for the treatment of AD.

Transcription factors Tp73, Cebpd, Pax6, and Spi1 rather than DNA methylation regulate chronic transcriptomics changes after experimental traumatic brain injury

Traumatic brain injury (TBI) induces a wide variety of cellular and molecular changes that can continue for days to weeks to months, leading to functional impairments. Currently, there are no pharmacotherapies in clinical use that favorably modify the post-TBI outcome, due in part to limited understanding of the mechanisms of TBI-induced pathologies. Our system biology analysis tested the hypothesis that chronic transcriptomics changes induced by TBI are controlled by altered DNA-methylation in gene promoter areas or by transcription factors. We performed genome-wide methyl binding domain (MBD)-sequencing (seq) and RNA-seq in perilesional, thalamic, and hippocampal tissue sampled at 3 months after TBI induced by lateral fluid percussion in adult male Sprague-Dawley rats. We investigated the regulated molecular networks and mechanisms underlying the chronic regulation, particularly DNA methylation and transcription factors. Finally, we identified compounds that modulate the transcriptomics changes and could be repurposed to improve recovery. Unexpectedly, DNA methylation was not a major regulator of chronic post-TBI transcriptomics changes. On the other hand, the transcription factors Cebpd, Pax6, Spi1, and Tp73 were upregulated at 3 months after TBI (False discovery rate < 0.05), which was validated using digital droplet polymerase chain reaction. Transcription regulatory network analysis revealed that these transcription factors regulate apoptosis, inflammation, and microglia, which are well-known contributors to secondary damage after TBI. Library of Integrated Network-based Cellular Signatures (LINCS) analysis identified 118 pharmacotherapies that regulate the expression of Cebpd, Pax6, Spi1, and Tp73. Of these, the antidepressant and/or antipsychotic compounds trimipramine, rolipramine, fluspirilene, and chlorpromazine, as well as the anti-cancer therapies pimasertib, tamoxifen, and vorinostat were strong regulators of the identified transcription factors, suggesting their potential to modulate the regulated transcriptomics networks to improve post-TBI recovery.

The cardioprotective efficacy of TVP1022 against ischemia/reperfusion injury and cardiac remodeling in rats

Following acute myocardial infarction (MI), early and successful reperfusion is the most effective strategy for reducing infarct size and improving the clinical outcome. However, immediate restoration of blood flow to the ischemic zone results in myocardial damage, defined as “reperfusion‐injury”. Whereas we previously reported that TVP1022 (the S‐isomer of rasagiline, FDA‐approved anti‐Parkinson drug) decreased infarct size 24 h post ischemia reperfusion (I/R) in rats, in this study we investigated the chronic cardioprotective efficacy of TVP1022 14 days post‐I/R. To simulate the clinical settings of acute MI followed by reperfusion therapy, we employed a rat model of left anterior descending artery occlusion for 30 min followed by reperfusion and a follow‐up for 14 days. TVP1022 was initially administered postocclusion–prereperfusion, followed by chronic daily administrations. Cardiac performance and remodeling were evaluated using customary and advanced echocardiographic methods, hemodynamic measurements by Millar Mikro‐Tip^® catheter, and histopathological techniques. TVP1022 administration markedly decreased the remodeling process as illustrated by attenuation of left ventricular enlargement and cardiac hypertrophy (both at the whole heart and the cellular level). Furthermore, TVP1022 inhibited cardiac fibrosis and reduced ventricular BNP levels. Functionally, TVP1022 treatment preserved cardiac wall motion. Specifically, the echocardiographic and most of the direct hemodynamic measures were pronouncedly improved by TVP1022. Collectively, these findings indicate that TVP1022 provides prominent cardioprotection against I/R injury and post‐MI remodeling in this I/R model.

Disease-Modifying Drugs in Parkinson's Disease

Despite an increased understanding of the pathogenesis of Parkinson's disease (PD), and a number of drugs designed to ameliorate symptoms, finding an effective neuroprotective therapy remains elusive. For decades now, several promising agents targeting different pathways have been explored as potential treatments that could help slow disease progression, but these have met with limited success. There are hurdles to overcome, particularly given that there is no exact animal model of PD and also no reliable biomarkers for PD. Without biomarkers, it is not possible to demonstrate, in the context of a clinical trial, that an intervention prevents neuronal degeneration. However, given the compelling scientific rationale of several compounds, an unrelenting pursuit continues. There have been hundreds of human studies looking at neuroprotection in PD. This article will briefly summarize several of the neuroprotective treatments that have been evaluated in large clinical trials, and will also outline some of the newer therapies that are currently being explored.

TVP1022: A Novel Cardioprotective Drug Attenuates Left Ventricular Remodeling After Ischemia/Reperfusion in Pigs

BACKGROUND

The current cornerstone treatment of myocardial infarction (MI) is restoration of coronary blood flow by means of thrombolytic therapy or primary percutaneous coronary intervention. However, reperfusion of ischemic myocardium can actually provoke tissue damage, defined as "ischemia-reperfusion (I/R) injury." TVP1022 [the S-isomer of rasagiline (Azilect), FDA-approved anti-Parkinson's drug] was found to exert cardioprotective activities against various cardiac insults, such as chronic heart failure and I/R, in rat models. Therefore, we tested the hypothesis that TVP1022 will provide cardioprotection against I/R injury and post-MI remodeling in a pig model.

METHODS

For inducing MI, we used an I/R model of midleft anterior descending artery occlusion for 90 minutes followed by follow-up for 8 weeks in 18 farm pigs (9 pigs in each group, MI + TVP1022 or MI + Vehicle). Echocardiographic measurements were performed and cardiac scar size was calculated using histopathological methods. For fibrosis evaluation, we measured the interstitial collagen volume fraction in the remote noninfarcted tissue.

RESULTS

TVP1022 administration significantly decreased cardiac scar size, attenuated left ventricular dilation, and improved cardiac function assessed by segmental circumferential strain analysis. Furthermore, TVP1022 significantly reduced myocardial fibrosis 8 weeks post-MI.

CONCLUSIONS

Collectively, these findings indicate that TVP1022 provides prominent cardioprotection against I/R injury and post-MI remodeling in this I/R pig model.

Rasagiline prevents neurodegeneration in thiamine deficient rats-a longitudinal MRI study

Neuroprotection is a therapeutic approach for the management of neurodegenerative diseases. Experimental thiamine deficiency (TD) in rats provides a model for selective neurodegeneration accompanied by chronic oxidative deficits. Rats exhibit neurological and cognitive impairments, which can be partially reversed by thiamine administration, enabling the study of mechanisms of neurodegeneration as well as neuroprotection. In this magnetic resonance (MR) study we used various techniques to characterize the neuroprotective effects of rasagiline, a selective MAO-B inhibitor. TD was induced by a thiamine-deficient diet and daily injections of the central thiamine antagonist, pyrithiamine. Daily injections of either saline or rasagiline (3mg/kg) were also administered to untreated-TD rats and rasagiline-treated TD rats respectively. With the appearance of neurological symptoms, all injections were terminated and thiamine was restored. MRI scans were performed before induction of TD (control values), on days 10, 12 (before symptoms appear), 14 (symptomatic stage) and during the recuperation period. Both groups were assessed using in-vivo serial T2-weighted imaging and diffusion tensor imaging (DTI), from which apparent diffusion coefficient (ADC) and fractional anisotropy (FA) maps were calculated. A histopathological evaluation was correlated with the MRI analysis. Thalamic hyperintensities were significantly smaller and less severe in the rasagiline-treated TD rats. Enlargement of the lateral ventricles was significantly less pronounced in the rasagiline-treated TD group. FA values of the untreated-TD group decreased significantly in the thalamic on days 12 and 14 and in the corpus callosum on day 14. These results demonstrate significant neuroprotection by rasagiline which could have implications for clinical neurodegenerative disorders.

Protective effect of rasagiline in aminoglycoside ototoxicity

Sensorineural hearing losses (SNHLs; e.g., ototoxicant- and noise-induced hearing loss or presbycusis) are among the most frequent sensory deficits, but they lack effective drug therapies. The majority of recent therapeutic approaches focused on the trials of antioxidants and reactive oxygen species (ROS) scavengers in SNHLs. The rationale for these studies was the prominent role of disturbed redox homeostasis and the consequent ROS elevation. Although the antioxidant therapies in several animal studies seemed to be promising, clinical trials have failed to fulfill expectations. We investigated the potential of rasagiline, an FDA-approved monomanine oxidase type B inhibitor (MAO-B) inhibitor type anti-parkinsonian drug, as an otoprotectant. We showed a dose-dependent alleviation of the kanamycin-induced threshold shifts measured by auditory brainstem response (ABR) in an ototoxicant aminoglycoside antibiotic-based hearing loss model in mice. This effect proved to be statistically significant at a 6-mg/kg (s.c.) dose. The most prominent effect appeared at 16kHz, which is the hearing sensitivity optimum for mice. The neuroprotective, antiapoptotic and antioxidant effects of rasagiline in animal models, all targeting a specific mechanism of aminoglycoside injury, may explain this otoprotection. The dopaminergic neurotransmission enhancer effect of rasagiline might also contribute to the protection. Dopamine (DA), released from lateral olivocochlear (LOC) fibers, was shown to exert a protective action against excitotoxicity, a pathological factor in the aminoglycoside-induced SNHL. We have shown that rasagiline enhanced the electric stimulation-evoked release of DA from an acute mouse cochlea preparation in a dose-dependent manner. Using inhibitors of voltage-gated Na(+)-, Ca(2+) channels and DA transporters, we revealed that rasagiline potentiated the action potential-evoked release of DA by inhibiting the reuptake. The complex, multifactorial pathomechanism of SNHLs most likely requires drugs acting on multiple targets for effective therapy. Rasagiline, with its multi-target action and favorable adverse effects profile, might be a good candidate for a clinical trial testing the otoprotective indication.

Recent advances in Parkinson’s disease therapy: use of monoamine oxidase inhibitors

Monoamine oxidase inhibitors inhibit dopamine metabolism and are therefore effective in treating Parkinson's disease, a condition associated with progressive striatal dopamine deficiency secondary to degeneration of dopaminergic neurons in the substantia nigra. Selegiline is currently the most widely used monoamine oxidase-B inhibitor for Parkinson's disease, but has a low and variable bioavailability, and is metabolized to L-methamphetamine and L-amphetamine that carry a risk for potential neurotoxicity. There are two new approaches that circumvent these potential disadvantages. First, selegiline orally disintegrating tablets provide a novel delivery form of selegiline, avoiding first pass metabolism by rapid absorption through the oral mucosa, thus leading to significantly lower plasma concentrations of L-metamphetamine and L-amphetamine. Selegiline orally disintegrating tablets prove to be clinically effective and safe in patients with moderately advanced Parkinson's disease. Second, rasagiline is a new monoamine oxidase inhibitor, without known neurotoxic metabolites. In large clinical trials, rasagiline proves effective as monotherapy in early Parkinson's disease, as well as adjunctive therapy to levodopa in advanced disease. Clinical data suggest, in addition, a disease-modifying effect of rasagiline that may correlate with neuroprotective activity of monoamine oxidase-B inhibitors in animal models of Parkinson's disease.

Rasagiline and rapid symptomatic motor effect in Parkinson's disease: review of literature

Rasagiline is a monoamine oxidase type-B inhibitor used as monotherapy or in addition to levodopa in the treatment of Parkinson's disease. Once daily administration of rasagiline makes it easy to use, and allows good compliance by patients and adherence to therapy. Several multicenter studies have noted the effectiveness of rasagiline on both motor and non-motor symptoms, which require a complex pharmacologic approach, such as cognitive disorders. A recent study also reported a rapid action of rasagiline on motor symptoms. Positive findings have been highlighted by an economic model study. This review analyzes the main studies of rasagiline, with particular attention to the effectiveness of the drug on motor symptoms.

Monoamine oxidase inhibitors and neuroprotection: a review

Monoamine oxidase inhibitors have been available for more than 50 years, initially developed as antidepressants but currently used in a variety of psychiatric and neurological conditions. There has been a recent surge of interest in monoamine oxidase inhibitors because of their reported neuroprotective and/or neurorescue properties. Interestingly, it seems that often these properties are independent of their ability to inhibit monoamine oxidase. This review article presents an overview of the neuroprotective/neurorescue properties of these multifaceted drugs and focuses on phenelzine, (-)-deprenyl, rasagiline, ladostigil, tranylcypromine, moclobemide, and clorgyline and their possible neuroprotective mechanisms.

Multi target neuroprotective and neurorestorative anti-Parkinson and anti-Alzheimer drugs ladostigil and m30 derived from rasagiline

Present anti-PD and -AD drugs have limited symptomatic activity and devoid of neuroprotective and neurorestorative property that is needed for disease modifying action. The complex pathology of PD and AD led us to develop several multi-target neuroprotective and neurorestorative drugs with several CNS targets with the ability for possible disease modifying activity. Employing the pharmacophore of our anti-parkinson drug rasagiline (Azilect, N-propagrgyl-1-R-aminoindan), we have developed a series of novel multi-functional neuroprotective drugs (A) [TV-3326 (N-propargyl-3R-aminoindan-5yl)-ethyl methylcarbamate)], with both cholinesterase-butyrylesterase and brain selective monoamine-oxidase (MAO) A/B inhibitory activities and (B) the iron chelator-radical scavenging-brain selective monoamine oxidase (MAO) A/B inhibitor and M30 possessing the neuroprotective and neurorescuing propargyl moiety of rasagiline, as potential treatment of AD, DLB and PD with dementia. Another series of multi-target drugs (M30, HLA-20 series) which are brain permeable iron chelators and potent selective brain MAO inhibitors were also developed. These series of drugs have the ability of regulating and processing amyloid precursor protein (APP) since APP and alpha-synuclein are metaloproteins (iron-regulated proteins), with an iron responsive element 5"UTR mRNA similar to transferring and ferritin. Ladostigil inhibits brain acetyl and butyrylcholinesterase in rats after oral doses. After chronic but not acute treatment, it inhibits MAO-A and -B in the brain. Ladostigil acts like an anti-depressant in the forced swim test in rats, indicating a potential for anti-depressant activity. Ladostigil prevents the destruction of nigrostriatal neurons induced by infusion of neurotoxin MPTP in mice. The propargylamine moiety of ladostigil confers neuroprotective activity against cytotoxicity induced by ischemia and peroxynitrite in cultured neuronal cells. The multi-target iron chelator M30 has all the properties of ladostigil and similar neuroprotective activity to ladostigil, but is not a ChE inhibitor. M30 has a neurorestorative activity in post-lesion of nigrostriatal dopamine neurons in MPTP, lacatcystin and 6-hydroxydopamine animal models of PD. The neurorestorative activity is related to the ability of the drug to activate hypoxia inducing factor (HIF) which induces the production of such neurotrophins as brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF) and erythropoietin as well as glia-derived neurotrophic factor (GDNF). The unique multiple actions of ladostigil and M30 make the potentially useful drugs for the treatment of dementia with Parkinsonian-like symptoms and depression.

I1 imidazoline receptor: novel potential cytoprotective target of TVP1022, the S-enantiomer of rasagiline

TVP1022, the S-enantiomer of rasagiline (Azilect®) (N-propargyl-1R-aminoindan), exerts cyto/cardio-protective effects in a variety of experimental cardiac and neuronal models. Previous studies have demonstrated that the protective activity of TVP1022 and other propargyl derivatives involve the activation of p42/44 mitogen-activated protein kinase (MAPK) signaling pathway. In the current study, we further investigated the molecular mechanism of action and signaling pathways of TVP1022 which may account for the cyto/cardio-protective efficacy of the drug. Using specific receptor binding and enzyme assays, we demonstrated that the imidazoline 1 and 2 binding sites (I₁ & I₂) are potential targets for TVP1022 (IC₅₀ = 9.5E-08 M and IC₅₀ = 1.4E-07 M, respectively). Western blotting analysis showed that TVP1022 (1–20 µM) dose-dependently increased the immunoreactivity of phosphorylated p42 and p44 MAPK in rat pheochromocytoma PC12 cells and in neonatal rat ventricular myocytes (NRVM). This effect of TVP1022 was significantly attenuated by efaroxan, a selective I₁ imidazoline receptor antagonist. In addition, the cytoprotective effect of TVP1022 demonstrated in NRVM against serum deprivation-induced toxicity was markedly inhibited by efaroxan, thus suggesting the importance of I₁imidazoline receptor in mediating the cardioprotective activity of the drug. Our findings suggest that the I₁imidazoline receptor represents a novel site of action for the cyto/cardio-protective efficacy of TVP1022.

Discovery of Multi-Target Agents for Neurological Diseases via Ligand Design

The incidence of neurological disorders in the developed world is rising in concert with an increase in human life expectancy, due in large part to better nutrition and health care. Even as drug discovery efforts are refocused on these disorders, there has been a dearth in the introduction of new disease-modifying therapies to prevent or delay their onset, or reverse their progression. Mounting evidence points to complex and heterogeneous etiopathologies that underlie these diseases. Therefore, it is unlikely that disorders in this class will be mitigated by any single drug that acts exclusively on a single pathway or target. The rational design of novel drug entities with the ability to simultaneously address multiple drug targets of a complex pathophysiology has recently emerged as a new paradigm in drug discovery. Similarly to the concept of multi-target agents within the psychopharmacology field, ligand design has gained an increasing prominence within the medicinal chemistry community. In this chapter we discuss several examples of select chemical scaffolds (polyamines, alkylxanthines, and propargyl carbamates) wherein these concepts were applied to develop novel drug candidates for Alzheimer's disease and Parkinson's disease.

Impact of pharmacological treatments on outcome in adult rodents after traumatic brain injury: a meta-analysis

Pharmacological treatments have been widely investigated in pre-clinical animal trials to evaluate their usefulness in reducing cognitive, behavioural and motor problems after traumatic brain injury (TBI). However, the relative efficacy of these agents has yet to be evaluated, making it difficult to assess the strength of evidence for their use in a clinical population. A meta-analytic review of research (1980-2009) was therefore conducted to examine the impact of pharmacological treatments administered to adult male rodents after experimental TBI on cognitive, behavioural, and motor outcome. The PubMed and PsycInfo databases were searched using 35 terms. Weighted Cohen's d effect sizes, percent overlap, Fail-Safe N statistics and confidence intervals were calculated for each treatment. In total, 91 treatments were evaluated in 223 pre-clinical trials, comprising 5988 rodents. Treatments that were investigated by multiple studies and showed large and significant treatment effects were of greatest interest. Of the 16 treatments that were efficacious, six improved cognition, 10 improved motor function and no treatment improved behaviour (depression/anxiety, aggression, zoosocial behaviour). Treatment benefits were found across a range of TBI models. Drug dosage and treatment interval impacted on treatment effects.

The promise of neuroprotective agents in Parkinson's disease

Parkinson’s disease (PD) is characterized by loss of dopamine neurons in the substantia nigra of the brain. Since there are limited treatment options for PD, neuroprotective agents are currently being tested as a means to slow disease progression. Agents targeting oxidative stress, mitochondrial dysfunction, and inflammation are prime candidates for neuroprotection. This review identifies Rasagiline, Minocycline, and creatine, as the most promising neuroprotective agents for PD, and they are all currently in phase III trials. Other agents possessing protective characteristics in delaying PD include stimulants, vitamins, supplements, and other drugs. Additionally, combination therapies also show benefits in slowing PD progression. The identification of neuroprotective agents for PD provides us with therapeutic opportunities for modifying the course of disease progression and, perhaps, reducing the risk of onset when preclinical biomarkers become available.

The cardioprotective efficacy of TVP1022 in a rat model of ischaemia/reperfusion

BACKGROUND AND PURPOSE

Because myocardial infarction is a major cause of morbidity and mortality worldwide, protecting the heart from the ischaemia and reperfusion (I/R) damage is the focus of intense research. Based on our in vitro findings showing that TVP1022 (the S-enantiomer of rasagiline, an anti-Parkinsonian drug) possesses cardioprotective effects, in the present study we investigated the hypothesis that TVP1022 can attenuate myocardial damage in an I/R model in rats.

EXPERIMENTAL APPROACH

The model consisted of 30-min occlusion of the left anterior descending artery followed by 4 or 24 h reperfusion. In addition, we investigated the possible mechanisms of cardioprotection in H9c2 cells and neonatal rat ventricular myocytes (NRVM) exposed to oxidative stress induced by H(2) O(2) .

KEY RESULTS

TVP1022 (20 and 40 mg·kg(-1) ) administered 5 min before reperfusion followed by an additional dose 4 h after reperfusion reduced the infarct size and attenuated the decline in ventricular function. TVP1022 also attenuated I/R-induced deterioration in cardiac mitochondrial integrity evaluated by mitochondrial swelling capacity. In vitro, using H9c2 cells and NRVM, TVP1022 attenuated both serum free- and H(2) O(2) -induced damage, preserved mitochondrial membrane potential and Bcl-2 levels, inhibited mitochondrial cytochrome c release and the increase in cleaved caspase 9 and 3 levels, and enhanced the phosphorylation of protein kinase C and glycogen synthase kinase-3β.

CONCLUSIONS AND IMPLICATIONS

TVP1022 provided cardioprotection in a model of myocardial infarction, and therefore should be considered as a novel adjunctive therapy for attenuating myocardial damage resulting from I/R injuries.

Type A monoamine oxidase regulates life and death of neurons in neurodegeneration and neuroprotection

In Parkinson's disease, type B monoamine oxidase (MAO-B) is proposed to play an important role in the pathogenesis through production of reactive oxygen species and neurotoxins from protoxicants, such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. In addition, inhibitors of MAO-B protect neurons in the cellular and animal models of Parkinson's and Alzheimer's diseases. However, the role of type A MAO (MAO-A) in neuronal death and neuroprotection by MAO-B inhibitors has been scarcely elucidated. This chapter presents our recent results on the involvement of MAO-A in the activation of mitochondrial death signal pathway and in the induction of prosurvival genes to prevent cell death with MAO-B inhibitors. The roles of MAO-A in the regulation of neuronal survival and death are discussed in concern to find a novel strategy to protect neurons in age-associated neurodegenerative disorders and depression.

The role of rasagiline in the treatment of Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder, affecting 1% to 2% of people older than 60 years. Treatment of PD consists of symptomatic therapies while neuroprotective strategies have remained elusive. Rasagiline is a novel, potent, and irreversible monoamine oxidase type B (MAO-B) inhibitor which has been approved for treatment of PD. Rasagiline inhibits MAO-B more potently than selegiline and has the advantage of once-daily dosing. In several large, randomized, placebo-controlled trials, rasagiline has demonstrated efficacy as monotherapy in early PD and as adjunctive therapy in advanced PD. In addition, rasagiline has been shown to have neuroprotective effects in in vitro and in vivo studies. The recently completed delayed-start ADAGIO (Attenuation of Disease Progression with Azilect Given Once-daily) trial suggests a potential disease-modifying effect for rasagiline 1 mg/day, though the clinical import of this finding has yet to be established.

The neuroprotective mechanism of 1-(R)-aminoindan, the major metabolite of the anti-parkinsonian drug rasagiline

The anti-parkinsonian drug, rasagiline [N-propargyl-1-(R)-aminoindan; Azilect(R)], is a secondary cyclic benzylamine and indane derivative, which provides irreversible, potent monoamine oxidase-B (MAO-B) inhibition and possesses neuroprotective and neurorestorative activities. A prospective clinical trial has shown that rasagiline confers significant symptomatic improvement and demonstrated alterations in Parkinson's disease progression. Rasagiline is primarily metabolized by hepatic cytochrome P-450 to form its major metabolite, 1-(R)-aminoindan, a non-amphetamine, weak reversible MAO-B inhibitor compound. Recent studies indicated the potential neuroprotective effect of 1-(R)-aminoindan, suggesting that it may contribute to the overall neuroprotective and antiapoptotic effects of its parent compound, rasagiline. This review article briefly highlights the molecular mechanisms underlying the neuroprotective properties of the active metabolite of rasagiline, 1-(R)-aminoindan, supporting the valuable potential of rasagiline for disease modification.

Recent developments in multiple system atrophy

Multiple system atrophy (MSA) is a rare late onset neurodegenerative disorder which presents with autonomic failure and a complicated motor syndrome including atypical parkinsonism, ataxia and pyramidal signs. MSA is a glial alpha-synucleinopathy with rapid progression and currently poor therapeutic management. This paper reviews the clinical features, natural history and novel diagnostic criteria for MSA as well as contemporary knowledge on pathogenesis based on evidence from neuropathological studies and experimental models. An outline of the rationale for managing symptomatic deterioration in MSA is provided together with a summary of novel experimental therapeutic approaches to decrease disease progression.

A randomized, double-blind, placebo-controlled, delayed start study to assess rasagiline as a disease modifying therapy in Parkinson's disease (the ADAGIO study): rationale, design, and baseline characteristics

A neuroprotective therapy is the single most important unmet medical need in Parkinson's disease. Several promising agents in the laboratory have been tested in the clinic, but none has been established in clinical trials to have a disease modifying effect despite positive results because of potential confounding symptomatic or pharmacologic effects. The delayed start design was developed to try to avoid a symptomatic confound when testing a putative neuroprotective therapy. In this study design, patients are randomly assigned to study drug or placebo in the first phase of the study, and both groups receive the active drug in the second phase. If benefits seen at the end of phase I persist through the end of phase II, they cannot be readily explained by a symptomatic effect (as patients in both groups are receiving the same medication) and benefits in the early start group must relate to the early initiation of the treatment. Although the precise mechanism responsible for such an effect can be debated, positive results in a delayed start study indicate that patients who receive early treatment have a better outcome than those where the treatment is delayed. We are using the delayed start design to assess the potential disease modifying effects of rasagiline in a prospective double blind controlled trial (the ADAGIO study). We here describe the rationale for the study and baseline characteristics of the 1,176 patients who have been enrolled into the trial.

Multifunctional neuroprotective derivatives of rasagiline as anti-Alzheimer's disease drugs

The recent therapeutic approach in which drug candidates are designed to possess diverse pharmacological properties and act on multiple targets has stimulated the development of the multimodal drugs, ladostigil (TV3326) [(N-propargyl-(3R) aminoindan-5yl)-ethyl methyl carbamate] and the newly designed multifunctional antioxidant iron chelator, M-30 (5-[N-methyl-N-propargylaminomethyl]-8-hydroxyquinoline). Ladostigil combines, in a single molecule, the neuroprotective/neurorestorative effects of the novel anti-Parkinsonian drug and selective monoamine oxidase (MAO)-B inhibitor, rasagiline (Azilect, Teva Pharmaceutical Co.) with the cholinesterase (ChE) inhibitory activity of rivastigmine. A second derivative of rasagiline, M-30 was developed by amalgamating the propargyl moiety of rasagiline into the skeleton of our novel brain permeable neuroprotective iron chelator, VK-28. Preclinical experiments showed that both compounds have anti-Alzheimer's disease activities and thus, the clinical development is oriented toward treatment of this type of dementia. This review discusses the multimodal effects of two rasagiline-containing hybrid molecules, namely ladostigil and M-30, concerning their neuroprotective molecular mechanisms in vivo and in vitro, including regulation of amyloid precursor protein processing, activation of protein kinase C, and mitogen-activated protein kinase signaling pathways, inhibition of cell death markers and upregulation of neurotrophic factors. Altogether, these scientific findings make these multifunctional compounds potentially valuable drugs for the treatment of Alzheimer's disease.

Induction of neurotrophic factors GDNF and BDNF associated with the mechanism of neurorescue action of rasagiline and ladostigil: new insights and implications for therapy

Parkinson's disease (PD) and Alzheimer's disease (AD) are the most common neurodegenerative disorders, although there is no drug or therapeutic treatment to demonstrate disease-modifying effects. Previous work has proposed that neurodegeneration is linked to a lack of trophic support in those neurons and brain areas associated with PD and AD. Indeed, previous studies have found that neurotrophic factors (NTFs) support neuronal survival in various cellular and animal models of PD and AD. Thus, attention has begun to turn to the possibility of NTF neuroprotective-neurorescue therapies for these diseases, indicating that NTFs may be of significant clinical importance as exogenously supplied or endogenously induced elements that obliterate neuronal deficits and degeneration. We have recently reported that the anti-PD drug rasagiline, the anti-AD drug ladostigil, and their propargyl moiety, propargylamine, enhanced the expression levels of brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor, endogenous NTFs associated with activation of phosphatidylinositol 3-kinase, protein kinase, and mitogen-activated protein kinase cell signaling/survival pathways. These studies indicate that the induction of NTFs by rasagiline and ladostigil might suppress apoptosis and induce neurorescue in neurodegenerative disorders and may support the drugs' possible disease-modifying mechanism of action.

Spotlight on rasagiline in Parkinson's disease

Rasagiline (Azilect) is a novel, selective, irreversible second-generation inhibitor of monoamine oxidase type B (MAO-B). It is administered orally once daily and is approved in the US, Canada, Mexico, Israel and the EU for use as monotherapy and as adjunct therapy in the treatment of Parkinson's disease. Results of well designed clinical studies indicate that rasagiline is effective as initial monotherapy and improves Parkinson's symptomatology in patients with early Parkinson's disease. In addition, when administered in conjunction with levodopa, in patients with moderate to advanced disease and motor fluctuations, rasagiline reduces mean daily 'off' time and increases daily 'on' time without troublesome dyskinesias, compared with controls. Rasagiline is generally well tolerated as monotherapy and adjunctive therapy and is administered once daily. Thus, rasagiline, administered as a simple and convenient dosage regimen, is a well tolerated and effective option for monotherapy in patients with early Parkinson's disease and for adjunctive therapy in patients with moderate to advanced disease.

Rasagiline is neuroprotective in a transgenic model of multiple system atrophy

Rasagiline is a novel selective irreversible monoamine oxidase-B (MAO-B) inhibitor recently introduced for the symptomatic treatment of Parkinson disease. Like other propargylamines rasagiline has also shown neuroprotective effects independent of MAO-B-inhibition in various in vitro and in vivo models. The present study was performed to test the potential of rasagiline as a disease-modifying agent in multiple system atrophy (MSA) using a transgenic mouse model previously described by our group. (PLP)-alpha-synuclein transgenic mice featuring glial cytoplasmic inclusion pathology underwent 3-nitropropionic acid intoxication to model full-blown MSA-like neurodegeneration. Two doses of rasagiline were used (0.8 and 2.5 mg/kg) for a treatment period of 4 weeks. Rasagiline-treated animals were compared to placebo saline-treated mice by evaluation of motor behaviour and neuropathology. Motor behavioural tests including pole test, stride length test and general motor score evaluation showed improvements in motor deficits associated with 2.5 mg/kg rasagiline therapy. Immunohistochemistry and histology showed significant reduction of 3-NP-induced neuronal loss in striatum, substantia nigra pars compacta, cerebellar cortex, pontine nuclei and inferior olives of MSA mice receiving 2.5 mg/kg rasagiline. The results of the study indicate that rasagiline confers neuroprotection in a transgenic mouse model of MSA and may therefore be considered a promising disease-modifying candidate for human MSA.

Rasagiline: a review of its use in the management of Parkinson's disease

Rasagiline (Azilect) is a novel, selective, irreversible second-generation inhibitor of monoamine oxidase type B (MAO-B). It is administered orally once daily and is approved in the US, Canada, Mexico, Israel and the EU for use as monotherapy and as adjunct therapy in the treatment of Parkinson's disease. Results of well designed clinical studies indicate that rasagiline is effective as initial monotherapy and improves Parkinson's symptomatology in patients with early Parkinson's disease. In addition, when administered in conjunction with levodopa, in patients with moderate to advanced disease and motor fluctuations, rasagiline reduces mean daily 'off' time and increases daily 'on' time without troublesome dyskinesias, compared with controls. Rasagiline is generally well tolerated as monotherapy and adjunctive therapy and is administered once daily. Thus, rasagiline, administered as a simple and convenient dosage regimen, is a well tolerated and effective option for monotherapy in patients with early Parkinson's disease and for adjunctive therapy in patients with moderate to advanced disease.

Treatment consideration and manifest complexity in comorbid neuropsychiatric disorders

Psychiatric disorders may co-occur in the same individual. These include, for example, substance abuse or obsessive-compulsive disorder with schizophrenia, and movement disorders or epilepsy with affective dysfunctional states. Medications may produce iatrogenic effects, for example cognitive impairments that co-occur with the residual symptoms of the primary disorder being treated. The observation of comorbid disorders in some cases may reflect diagnostic overlap. Impulsivity, impulsiveness or impulsive behaviour is implicated in a range of diagnostic conditions including substance abuse, affective disorder and obsessive-compulsive disorder. These observations suggest a need to re-evaluate established diagnostic criteria and disorder definitions, focusing instead on symptoms and symptom-profiles.

Rasagiline Promotes Regeneration of Substantia Nigra Dopaminergic Neurons in Post-MPTP-induced Parkinsonism via Activation of Tyrosine Kinase Receptor Signaling Pathway

The anti-Parkinson drug rasagiline (Azilect), an irreversible and selective monoamine oxidase (MAO)-B inhibitor, was shown to possess neuroprotective activities, involving multiple survival pathways among them the up-regulation of protein kinase C (PKC)alpha, PKCepsilon, the anti-apoptotic Bcl-2, Bcl-xL, and Bcl-w and the induction of brain-derived- and glial cell line-derived neurotrophic factors (BDNF, GDNF). More recently, employing conventional neurochemical techniques, as well as transcriptomic and proteomic screening tools, combined with a biology-based clustering method, it was shown that rasagiline also possesses neurorescue/neurogenesis activity in mice midbrain dopaminergic neurons when given chronically, post-MPTP (N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine). This action was attributed to the activation of cell signaling mediators associated with neurotrophic factors responsive-tyrosine kinase receptor (Trk) pathway, including ShcC, SOS, AF6, Rin1, and Ras and the increase in the Trk-downstream effecter phosphatidylinositol 3 kinase (PI3K) protein and its substrate, Akt/PKB. It is interesting to determine whether a similar effect is seen in Parkinsonian patients after long-term treatment with rasagiline, which may have implications as a possible disease modifying agent.

Monamine oxidase inhibitors: current and emerging agents for Parkinson disease

Monoamine oxidase type B (MAO-B) is the predominant isoform responsible for the metabolic breakdown of dopamine in the brain. Selective inhibition of brain MAO-B results in elevation of synaptosomal dopamine concentrations. Data have been reported regarding the selective MAO-B inhibitors, rasagiline and selegiline, for the symptomatic treatment of Parkinson disease (PD). Selegiline has demonstrated efficacy as monotherapy in patients with early PD (Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism study), but evidence of selegiline efficacy as adjunctive treatment in levodopa-treated PD patients with motor fluctuations is equivocal. A new formulation of selegiline (Zydis selegiline) has been evaluated in 2 small, placebo-controlled studies as adjunctive therapy to levodopa. The Zydis formulation allows pregastric absorption of selegiline, minimizing first-pass metabolism, and thereby increasing selegiline bioavailability and reducing the concentration of amphetamine metabolites. Rasagiline is a selective, second-generation, irreversible MAO-B inhibitor, with at least 5 times the potency of selegiline in vitro and in animal models. Rasagiline has demonstrated efficacy in 1 large, randomized, double-blind, placebo-controlled trial (TVP-1012 in Early Monotherapy for Parkinson's Disease Outpatients) as initial monotherapy in patients with early PD, and in 2 large, controlled trials (Parkinson's Rasagiline: Efficacy and Safety in the Treatment of "Off," Lasting Effect in Adjunct Therapy With Rasagiline Given Once Daily) as adjunctive treatment in levodopa-treated PD patients with motor fluctuations. Unlike selegiline, rasagiline is an aminoindan derivative with no amphetamine metabolites. A randomized clinical trial is underway to confirm preclinical and preliminary clinical data suggesting rasagiline has disease-modifying effects.