CNS & Neurological Disorders - Drug Targets (Formerly Current Drug Targets - CNS & Neurological Disorders) - Volume 17, Issue 1, 2018

Background & Objective: Clinical depression is an unsatisfactory mood disorder affecting millions of people worldwide. The disorder is associated with a phenomenal number of suicidal attempts each year, and it has been estimated that 10-20 million people around the world made an attempt of suicide in some stage of the disease. Thus, medicinal intervention is ultimately required to avoid such type of extreme outcomes. There are numerous therapeutic antidepressant options in clinical practice, however, most of them face the challenge of efficacy, side effects, and patient compliance. In this scenario, new effective and safe therapeutic agents are becoming the major focus of researchers in the area of neuropharmacology, who and are evaluating different sources such as synthetic and natural therapeutics. Similarly, thousands of peptides have already shown vital role in human physiology for regulation of different activities. Conclusion: This mini-review will focus on peptides with reported antidepressant activity, along with their mechanism of action. Furthermore, the present article summarizes the literature pertaining to these peptides as antidepressant agents.

Parkinson's disease (PD) is the most prevalent movement disorder in the world. The major pathological hallmarks of PD are death of dopaminergic neurons and the formation of Lewy bodies. At the moment, there is no cure for PD; current treatments are symptomatic. Investigators are searching for neuroprotective agents and disease modifying strategies to slow the progress of neurodegeneration. However, due to lack of data about the main pathological sequence of PD, many drug targets failed to provide neuroprotective effects in human trials. Recent evidence suggests the involvement of C-Abelson (c-Abl) tyrosine kinase enzyme in the pathogenesis of PD. Through parkin inactivation, alpha synuclein aggregation, and impaired autophagy of toxic elements. Experimental studies showed that (1) c-Abl activation is involved in neurodegeneration and (2) c-Abl inhibition shows neuroprotective effects and prevents dopaminergic neuronal' death. Current evidence from experimental studies and the first in-human trial shows that c-Abl inhibition holds the promise for neuroprotection against PD and therefore, justifies the movement towards larger clinical trials. In this review article, we discussed the role of c-Abl in PD pathogenesis and the findings of preclinical experiments and the first in-human trial. In addition, based on lessons from the last decade and current preclinical evidence, we provide recommendations for future research in this area.

Background & Objective: Vascular dementia is the second most common cause of dementia, with clinical features that depend on neural substrates affected by the vascular lesions. Like most neurological disorders, it involves alterations that range from the molecular level to neuronal networks. Such alterations begin as compensatory mechanisms that reshape every subsystem involved in the brain's homeostasis. Although there have been recent huge advances in understanding the pathophysiology of cognitive dysfunction, a suitable therapeutic approach to vascular dementia remains elusive. Pharmacological interventions have failed to sustainably improve cognitive function, and it is a well-known fact that there is a need to change the current view for providing neuroprotection and enhancing neurorecovery after stroke. Studies regarding cognitive training are also faced with the difficulty of drawing up protocols that can embrace a holistic approach in cognitively impaired patients. Conclusion: This review will present a brief synthesis of current results from basic research data and clinical studies regarding pharmacological and non-pharmacological interventions in vascular dementia and will offer an integrated view from the perspective of systems biology.

Background and Objective: This paper was based on a literature search of PubMed and Scielo databases using the keywords “Flavonoids, Neuroprotection, Quercetin, Rutin, Isoquercitrin, Alzheimer, Parkinson, Huntington” and combinations of all the words. Method: We collected relevant publications, during the period of 2000 to 2016, emphasizing in vivo and in vitro studies with neurological assessment of flavonol's potentials, as well as classifying studies according to evidence levels, in order to elucidate evidence-based literature and its application on clinical research. In addition, we highlight the importance of flavonols in modern research fields, indicating their neuroprotective potential and use thereof as preventive and therapeutic treatment of numerous neurodegenerative disease. Neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease and Huntington's disease, represent worldwide a major health problem with great financial impact. They are multifactorial diseases, hallmarked by similar pathogenesis that covers conditions such as oxidative stress, formation of free radicals, abnormal protein dynamics (degradation and aggregation), mitochondrial dysfunction, lipid peroxidation and cellular death or senescence. Flavonols are polyphenolic compounds, widely distributed in the plant kingdom and found in high concentrations in vegetables, fruits and teas. Their neuroprotective effects are mainly related to their antioxidant, anti-proliferative and anti-inflammatory properties. Conclusion: It was this paper's intention to contribute with an evidence analysis of recent studies approaching neuroprotective effects of flavonols and the potential to conduct human clinical studies.

Background: Donepezil (DPZ) is widely prescribed as a specific and reversible acetylcholinesterase inhibitor for the symptomatic treatment of mild to moderate Alzheimer's disease (AD). Objective: Considering the therapeutic potential of DPZ and the advantages offered by the intranasal route as an alternative for drug administration, the aim of this study was the development and characterization of a DPZ microemulsion (ME) for nose-to-brain delivery. Method: The ME was developed by construction of pseudoternary phase diagrams and characterized by dynamic light scattering and transmission electron microscopy. Flow properties and viscosity, as well as optical stability and stability under storage at different temperatures were evaluated. Finally, in vitro release and ex vivo permeation studies through porcine nasal mucosa were accomplished. Results: A transparent and homogeneous DPZ-ME (12.5 mg/ml) was obtained. The pH and viscosity were 6.38 and 44.69 mPa·s, respectively, indicating nasal irritation prevention and low viscosity. The mean droplet size was 58.9±3.2 nm with a polydispersity index of 0.19±0.04. The morphological analysis revealed the spherical shape of droplets, as well as their smooth and regular surface. Optical stability evidenced no destabilization processes. DPZ release profile indicated that the ME followed a hyperbolic kinetic model while the ex vivo permeation profile showed that the highest permeation occurred during initial 4 h and the maximum permeated amount was approximately 2000 μg, which corresponds to 80% of the starting amount of drug. Conclusion: We conclude that our nasal ME could be considered as a new potential tool for further investigation in the AD.

Objective and Background: Inhibition of acetylcholinesterase (AChE) has gained much importance since the discovery of the involvement of peripheral anionic site as an allosteric regulator of AChE. Characterized by the formation of β-amyloid plaques, Alzheimer's disease (AD) is currently one of the leading causes of death across the world. Progression in this neurodegenerative disorder causes deficit in the cholinergic activity that leads towards cognitive decline. Therapeutic interventions in AD are largely focused upon AChE inhibitors designed essentially to prevent the loss of cholinergic function. The multifactorial AD pathology calls for Multitarget-directed ligands (MTDLs) to follow up on various components of the disease. Considering this approach, other related AD targets were also selected. Structure-based virtual screening was relied upon for the identification of lead compounds with anti-AD effect. Method: Several chemoinformatics approaches were used in this study, reporting four multi-target inhibitors: MCULE-7149246649-0-1, MCULE-6730554226-0-4, MCULE-1176268617-0-6 and MCULE-8592892575-0-1 with high binding energies that indicate better AChE inhibitory activity. Additional in-silico analysis hypothesized the abundant presence of aromatic interactions to be pivotal for interaction of selected compounds to the acetyl-cholinesterase. Additionally, we presented an alternative approach to determine protein-ligand stability by calculating the Gibbs-free energy change over time. Furthermore, this allows to rank potential hits for further in-vitro testing. Results and Conclusion: With no predicted indication of adverse effects on humans, this study unravels four active multi-target inhibitors against AChE with promising affinities and good ADMET profile for the potential use in AD treatment.

Background: Depressive disorders are common during pregnancy. There is compelling evidence that the inflammatory response system is important in the pathophysiology of depression. Higher concentrations of proinflammatory cytokines including tumor necrosis factor-alpha (TNF-α) in depressed subjects have been described. Because several polymorphisms in the TNF-α promoter region are known to affect its gene expression, the aim of this study was determine whether TNF-α - 857C/T, -308G/A, and -238G/A polymorphisms confer susceptibility to depression during pregnancy in a Mexican mestizo population. Methods: This case-control study involved 153 depressed pregnant women and 177 controls. Polymorphisms were genotyped using real-time PCR. Odds ratios (OR) and 95% confidence intervals adjusted by age, body mass index, number of pregnancies, months of pregnancy and number of abortions were used to estimate risk. Results: The -857CT genotype was found to increase the risk for depression (OR= 1.73, 95% CI= 1.06-2.82). In contrast, the -238GA genotype reduced the risk (OR= 0.33, 95% CI= 0.14-0.72). The - 308G/A polymorphism was not associated with risk for depression. Finally, the C857-G308-A238 haplotype was associated with a decreased risk of depression (OR= 0.35, 95% CI= 0.15-0.82). Conclusion: Our results show for the first time an association between TNF-α -857C/T and -238G/A polymorphisms and prenatal depression in Mexican mestizo population.