CNS & Neurological Disorders - Drug Targets - Volume 15, Issue 1, 2016

Epilepsy is one of the most common neurological disorders in humans, and the role of cerebellum in its physiopathology remains the subject of study. Bergmann glia in the cerebellar cortex regulates the homeostasis of Purkinje cells, the axons of which target the dentate and interpositus nuclei, which form the main cerebellar output to other structures in the central nervous system involved in Epilepsy. Sox-1 is a transcription factor expressed in Bergmann glia and its binding to β-Catenin further inhibits the Wnt pathway. β-Catenin is widely expressed in cerebellum. It has been reported that β-Catenin signaling is increased as the hippocampus receives repeated electrical stimuli and this is related with apoptosis of neurons. In the cerebellum, the recurrence of seizures results in Purkinje cells death, although the mechanisms remain unclear.

Painful peripheral neuropathies resulting from cancer chemotherapy treatment is frequently dose-dependent and may diminish following dose reduction or termination of chemotherapy. However, dose reduction or treatment termination could lead to reemergence of the cancer. In addition, chemotherapy-induced peripheral neuropathy (CIPN) may persist long after termination of chemotherapy. Thus, there is a need for treatments to ameliorate pain during the course of an effective cancer treatment regimen. Because the mechanism underlying CIPN has yet to be fully characterized, there is a current lack of effective treatments for CIPN. Preclinical studies in CIPN rodent models have suggested a number of potential neuropathological mechanisms, which could serve as platforms for the development of novel therapeutics. Although a number of potential analgesic therapies have demonstrated robust efficacy in preclinical studies, rigorous clinical testing has yet to fully validate the preclinical findings. The lack of congruence between preclinical and clinical findings could be in part due to the phylogenetic distance between the main model species and humans. Thus, a CIPN model in nonhuman primates could serve to bridge the translational gap between laboratory findings in small animals and clinical utility. The current review points out the short comings of current CIPN rodent models and suggests the use of large animals, such as the nonhuman primate, to narrow the translational gap between preclinical and clinical findings and the discovery of novel therapeutics.

The development and evolution of targeted therapy to any disease require the identification of targets amenable to treatment of patients. Here the pathogenetic signalling systems involved in multiple sclerosis are scrutinised to locate nodes of deregulation and dysfunction in order to devise strategies of drug development for targeted intervention. Oliogoclonal bands (OCB) are isoelectric focusing profiles of immunoglobulins synthesised in the central nervous system. OCBs enable the diagnosis of multiple sclerosis with high sensitivity and specificity and are related to the course of the disease and progression. The OCB patterns can be linked with the expression of angiogenic molecular species. Angiogenic signalling which has also been implicated in demyelination provides the option of using angiogenesis inhibitors in disease control. The PI3K (phosphoinositide 3-kinase)/Akt axis has emerged with a key role in myelination with its demonstrable links with mTOR mediated transcription of downstream target genes. Inflammatory signals and innate and acquired immunity from the activation of NF-ΚB (nuclear factor ΚB) responsive genes are considered. NF-ΚB signalling could be implicated in myelination. The transcription factor STAT (signal transducers and activators of transcription) and the EBV (Epstein- Barr virus) transcription factor BZLF1 contributing significantly to the disease process are a major environmental factor linked to MS. EBV can activate TGF (transforming growth factor) and VEGF (vascular endothelial growth factor) signalling. EBV microRNAs are reviewed as signalling mediators of pathogenesis. Stem cell transplantation therapy has lately gained much credence, so the current status of mesenchymal and hematopoietic stem cell therapy is reviewed with emphasis on the differential expression immune-related genes and operation of signalling systems.

Objective. To review the antidepressant efficacy of S-Adenosyl-L-Methionine (SAMe) both in monotherapy and/or in augmentation with antidepressants to better understand its potential role in the treatment of patients with Major Depressive Disorder (MDD) and Treatment-Resistant Depression (TRD). Data Sources: A MEDLINE/PubMed search was carried out by using the following set of keywords: ((SAMe OR SAdenosyl- L-Methionine) AND (major depressive disorder OR depression)). Data Selection and Data Extraction: No language or time restrictions were placed on the electronic searches. Randomized controlled trials and open trials involving humans were here included and analyzed. The references of published articles identified in the initial search process were also examined for any additional studies appropriate for the review. Data Synthesis: SAMe is an important physiologic compound, playing a central role as precursor molecule in several biochemical reactions. Numerous studies have shown that SAMe may affect the regulation of various critical components of monoaminergic neurotransmission involved in the pathophysiology of MDD. Some findings have suggested its antidepressant efficacy in treating MDD. Several randomized controlled trials have supported that the antidepressant efficacy of SAMe in monotherapy is superior to placebo and tricyclic antidepressants. Recent findings have also demonstrated its efficacy in patients nonresponsive to selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors. Conclusion: Overall, SAMe is a well-tolerated medication, which may offer considerable advantages as an alternative to antidepressant drugs or as an add-on therapy in the treatment of MDD and TRD. More large-scale controlled trials are needed to gain a better understanding of the relative efficacy of this drug.

Introduction: Coenzyme Q10 (CoQ10) is an antioxidant that enhances the activity of complex I and II in the Electron Transport Chain. Many preclinical and clinical studies evaluated CoQ10 for neuroprotection against Parkinson disease (PD). The aim of this study is to synthesize evidence from published randomized controlled trials (RCTs) about the benefit of CoQ10 supplementation for patients with Parkinson disease. Methods: We followed the PRISMA statement guidelines during the preparation of this systematic review and metaanalysis. A computer literature search for (PubMed, EBSCO, Web of science and Ovid Midline) was carried out. We included RCTs comparing CoQ10 with placebo in terms of motor functions and quality of life. Outcomes of total Unified Parkinson Disease Rating Scale (UPDRS), UPDRS I, UPDRS II, UPDRS III and Schwab and England scores were pooled as standardized mean difference (SMD) between two groups from baseline to the endpoint. Results: Five RCTs (981 patients) were included in this study. The overall effect did not favor either of the two groups in terms of: total UPDRS score (SMD -0.05, 95%CI [-0.10, 0.15]), UPDRS I (SMD -0.03, 95% CI [-0.23, 0.17]), UPDRS II (SMD -0.10, 95%CI [-0.35, 0.15]), UPDRS III (SMD -0.05, 95%CI [-0.07, 0.17]) or Schwab and England score (SMD 0.08, 95%CI [-0.13, 0.29]). Conclusion: CoQ10 supplementation does not slow functional decline nor provide any symptomatic benefit for patients with Parkinson disease.

Gliomas are often recognized as highly heterogeneous cancerous phenotype. They are perpetually recurrent, obstinately resistant to treatment and hence almost incurable. Drug development studies to date have revealed only modest effect in attenuating growth of these tumors. The present study was aimed at elucidating the potential of targeting glioma through a novel combination of drugs in comparison to single agent. Here, we show that the combined administration of Caffeic acid phenethyl ester [CAPE] and Dasatinib exerts a strong antitumor action on C6 glioma cells. Combinational treatment inhibits proliferation, induces apoptosis, modulates astrocytic phenotype and decreases cell density. Results suggest that combinational therapy inhibits migration and invasiveness, decreases cell survival fraction and hence clonogenic property of C6 cells. The Nitric oxide [NO] levels were significantly reduced by combination treatment at all time points and effect was persistent over the time in comparison to single drug treatment. Atomic Absorption Spectroscopy [AAS] analysis of intracellular and extracellular calcium revealed that the treatment with CAPE and Dasatinib strongly modulates the calcium [Ca2+] levels. Herein, we demonstrate that treatment of C6 glioma cells with CAPE and Dasatinib significantly decrease the activity of catalase [CAT]. The results in totality suggest that the combinational therapy remarkably reduces the proliferation of glioma cells possibly through different mechanisms, targeting multiple pathways involved in tumor growth, proliferation and development implicating the relevance of using these drugs in combination therapy for effective treatment of glioma. In vitro results suggest that CAPE and Dasatinib cotreatment could be therapeutically exploited for the management of gliomas.

Recent findings have demonstrated a dual effect of the folic acid (FA) supplementation on the nervous system of rats. We found that FA treatment prevented memory impairment and Na+, K+- ATPase inhibition in the striatum and cortex in adult rats that suffered neonatal hypoxia-ischemia (HI). However, spatial memory deficit has been associated with FA supplementation. In the present study we investigated the role of FA supplementation on spatial memory and Na+, K+-ATPase activity in the hippocampus, as well as on morphologic alterations in adolescent rats submitted to neonatal HI. Wistar rats of both sexes at postnatal day (PND) 7 were submitted to Levine-Rice HI procedure. Intraperitoneal doses of FA were administered immediately before HI and repeated daily until the maximum PND 40. Hippocampal volume and striatum area were estimated and Na+, K+-ATPase activity in the hippocampus was measured at PND 31. Also, the performance of the animals in the water maze was assessed and Na+, K+-ATPase activity measured again at PND 52. Interestingly, HI and FA resulted in spatial memory deficits in the Morris water maze and the Na+, K+-ATPase activity was impaired at PND 31 in HI rats which received FA. Additionally, Na+, K+-ATPase activity in adulthood showed a decrease after HI and a recovery in supplemented animals. Hippocampal and striatal atrophy were partially reversed by FA. To conclude, the present results support the hypothesis that FA supplementation during development contributes to memory deficits caused by HI and Na+, K+-ATPase failure in adolescent rats, although, in adulthood, FA has been effective in reversing enzymatic activity in the hippocampus.

The transcription factor Pax6 is a well-accepted neurogenic determinant during development, in adult neural progenitor cells and in acute brain injury models. In the adult brain Pax6 is expressed in selective populations of dopaminergic neurons, and thus may have a role to play in Parkinson’s disease (PD). This study looked at post-mortem tissue from patients with PD and in particular the substantia nigra which showed a reduced number of PAX6+ cells compared to age and sex matched control tissue. In an animal model of PD, there was an early transient increase in the number of SN Pax6+ cells at the time of cell loss through apoptosis. Finally we showed that an over-expression of Pax6 in SH-SY5Y cells treated with PD relevant neurotoxins, resulted in an increase in cell survival and a reduction in markers of apoptosis and oxidative stress. These results suggest that Pax6 may have a role to play in the loss of dopaminergic neurons in PD.

Background: Dyslipidemia is a risk factor for the pathogenesis of Alzheimer's disease. Although, atorvastatin is a well-accepted lipid-lowering agent, the benefits of atorvastatin treatment through an anti-inflammatory mechanism are still unclear. Objective: The present study was designed to examine changes in inflammatory markers following administration of atorvastatin in dyslipidemic patients with a parental history of Alzheimer's disease. Methods: Dyslipidemic adults with a parental history of Alzheimer's disease were administered either 40 mg of atorvastatin or placebo for 18 months. Before and after the study, lpid levels, blood pressure, body weight and body mass index, and the inflammatory markers hs-Creactive protein, serum monocyte chemoattractant protien-1, interleukin-1β, interleukin-6, and tumor necrosis factor-α were tested. Results: Baseline levels of lipids, body mass index, hs-Creactive protein, monocyte chemoattractant protien-1, interleukin- 1β, interleukin-6 and tumor necrosis factor-α did not show any difference between the two groups. However, after 18 months of atorvastatin treatment, all inflammatory markers significantly decreased in association with a reduction of lipid profiles, body mass index, bodyweight, and blood pressure, compared with those patients treated with placebo. Conclusion: Administration of atorvastatin corrected dyslipidemia in association with a reduction in inflammatory markers. Our results suggest that the therapeutic benefits of atorvastatin possibly involve an anti-inflammatory pathway.

Alzheimer’s disease (AD) is the leading neurodegenerative disorder affecting the world’s elderly population. Most experimental models of AD are transgenic or pharmacological in nature, and do not simulate the entire pathophysiology. In the present study, we developed a pharmacologically induced AD using the zebrafish, a species that can recapitulate most of the phenotypes of the disease. The pharmacological agent being used, okadaic acid (OKA) has also been utilized to study AD in other species. In this model, the immunohistochemistry of phosphorylated glycogen synthase-3α/β, Aβ, p-tau, tau protein, and senile plaque formation in zebrafish brain were all significantly increased with increasing exposure to OKA. These represent the majority of the histological hallmarks of AD pathophysiology. The observed changes were also accompanied by learning and memory deficits which are also important components in AD pathophysiology. Zebrafish disease models are gaining popularity mostly due to their economic cost and relevance to human disease pathophysiology. Current pharmacological methods of inducing AD in zebrafish are not adequately developed and do not represent all the features of the disease. OKA-induced AD in zebrafish can become a cost efficient model to study drug discovery for AD. It may also be used to unravel the molecular mechanisms underlying the complex pathophysiology that leads to AD using relatively economical species.

Dystonia is a hyperkinetic disabling movement disorder. In the dtsz hamster, a model of paroxysmal dystonia, pronounced antidystonic effects of the KV7.2-5 potassium channel opener retigabine and aggravation of dystonia by a selective KV7.2-5 blocker indicated a pathophysiological role of an abnormal expression of KV7 channels. We therefore investigated the expression of KV7 subunits in brains of dystonic hamsters. While KV7.2 and KV7.3 subunits were unaltered, lower KV7.5 mRNA levels became evident in motor areas and in limbic structures of dystonic hamsters. The KV7.2/3 subunit-preferring channel opener N-(6-chloropyridin-3-yl)-3,4- difluorobenzamide (ICA 27243; 10-30 mg/kg i.p.) failed to reduce the severity of dystonia in mutant hamsters, suggesting that the previously observed antidystonic action of retigabine is mediated by the activation of KV7.5 channels. The experiments indicate a functional relevance for KV7.5 channels in paroxysmal dystonia. We suggest that compounds highly selective for subtypes of KV7 channels, i.e. for KV7.5, may provide new therapeutic approaches.

Oxidative stress and mitochondrial disturbances are the common and important causative factors of aging, and play an important role in the late onset of sporadic neurodegenerative diseases, including Alzheimer disease (AD). Furthermore, emerging evidence from in vitro and in vivo disease models suggests that oxidative stress and increased vulnerability to induction of mitochondrial permeability transition leads to the pathogenesis of the neurological disorders. Towards the goals of developing effective neuroprotectors, this article describes the synthesis and neuroprotective studies of various derivatives of the naturally occurring alkaloid securinine, based on which a lead compound, allomargaritarine (a diastereomer of margaritarine), was identified as an effective therapeutic for neuroprotection. Allomargaritarine exhibits high antioxidant activity, and has significant mitoprotective effect on cellular models of neurodegeneration.

Objective: Determine if donepezil will raise the insulin-like growth factor-1 levels of patients with amnestic mild cognitive impairment and Alzheimer's disease. Design: In an outpatient setting, recruit amnestic mild cognitive impairment and Alzheimer's disease patients who were to start treatment with donepezil. Measure total serum insulin-like growth factor-1 levels before and after 3-6 months of treatment. Results: Twenty-four patients were recruited. After a mean duration of 129 ± 37 days, 14 patients returned taking 5 mg (n=4) or 10 mg (n=10) donepezil per day. Twelve patients experienced decreases in their insulin-like growth factor-1 levels, one had no change, and one experienced an increase. Their mean insulin-like growth factor-1 level dropped by 13%, from 113 ± 31 ng/ml to 98 ± 28 ng/ml (p<0.001). Conclusion: Contrary to the expected increase in insulin-like growth factor-1 levels in response to donepezil that has been reported for normal elderly adults, our patients experienced decreases. This finding suggests that the somatotropic axis is altered in amnestic mild cognitive impairment and Alzheimer's disease relative to normal older adults.

Alzheimer disease (AD) is one of the most common neurodegenerative disorders widely occurring among the elderly. The pathogenic mechanisms involved in the development of this disease are still unknown. In AD, in addition to brain, a number of peripheral tissues and cells are affected, including erythrocytes. In this study, we analyzed glycolytic energy metabolism, antioxidant status, glutathione, adenylate and proteolytic systems in erythrocytes from patients with AD and compared with those from age-matched controls and young adult controls. Glycolytic enzymes hexokinase, phosphofructokinase, bisphosphoglycerate mutase and bisphosphoglycerate phosphatase displayed lower activities in agematched controls, and higher activities in AD patients, as compared to those in young adult control subjects. In both aging and AD, oxidative stress is increased in erythrocytes whereas elevated concentrations of hydrogen peroxide and organic hydroperoxides as well as decreased glutathione/glutathione disulfide ratio and glutathione transferase activity can be detected. These oxidative disturbances are also accompanied by reductions in ATP levels, adenine nucleotide pool size and adenylate energy charge. Caspase-3 and calpain activities in age-matched controls and AD patients were about three times those of young adult controls. 2,3-diphosphoglycerate levels were significantly decreased in AD patients. Taken together these data suggest that AD patients are associated with chronic disturbance of 2,3-diphosphoglycerate metabolism in erythrocytes. These defects may play a central role in pathophysiological processes predisposing elderly subjects to dementia.