Safinamide: a new hope for Parkinson's disease?

BDNF/TrkB activators in Parkinson's disease: A new therapeutic strategy

Parkinson's disease (PD) is a neurodegenerative disorder of the brain and is manifested by motor and non-motor symptoms because of degenerative changes in dopaminergic neurons of the substantia nigra. PD neuropathology is associated with mitochondrial dysfunction, oxidative damage and apoptosis. Thus, the modulation of mitochondrial dysfunction, oxidative damage and apoptosis by growth factors could be a novel boulevard in the management of PD. Brain-derived neurotrophic factor (BDNF) and its receptor tropomyosin receptor kinase type B (TrkB) are chiefly involved in PD neuropathology. BDNF promotes the survival of dopaminergic neurons in the substantia nigra and enhances the functional activity of striatal neurons. Deficiency of the TrkB receptor triggers degeneration of dopaminergic neurons and accumulation of α-Syn in the substantia nigra. As well, BDNF/TrkB signalling is reduced in the early phase of PD neuropathology. Targeting of BDNF/TrkB signalling by specific activators may attenuate PD neuropathology. Thus, this review aimed to discuss the potential role of BDNF/TrkB activators against PD. In conclusion, BDNF/TrkB signalling is decreased in PD and linked with disease severity and long-term complications. Activation of BDNF/TrkB by specific activators may attenuate PD neuropathology.

Impact of Safinamide on Patient-Reported Outcomes in Parkinson's Disease

Introduction

Parkinson's disease (PD) is a chronic and progressive neurodegenerative condition due to the degeneration of nigral dopaminergic cells. Both motor and non-motor symptoms (NMS) of PD produce a marked impairment in PD patients' quality of life (QoL), but contrary to motor features, NMS do not improve with dopamine replacement. Novel therapeutic interventions for PD have successfully controlled most motor manifestations of PD, but the management of NMS is still challenging. Since NMS have a negative impact on the QoL of PD patients, researchers are currently looking for drugs that can modulate the activity of neurotransmitter systems other than dopamine in the hope that can alleviate NMS in PD. Among the recently approved drugs for patients experiencing fluctuations in motor symptoms, safinamide stands out as an effective add-on therapy to levodopa. Safinamide is a monoamine oxidase type-B inhibitor (MAOB-I), with proven efficacy in reducing motor fluctuations. Its distinctive mechanism of action impacts dopaminergic pathways via MAOB inhibition and glutamatergic pathways by blocking sodium and calcium channels. Findings from Phase III clinical trials, meta-analysis, post-hoc analysis, and real-life experiences indicate that safinamide benefits motor symptoms such as tremor, bradykinesia, rigidity, and gait. Additionally, it shows promise for improving NMS like fatigue, pain, mood, and sleep disturbances in patients with PD.

Areas Covered

In this article, the authors explore the impact of safinamide on patient-reported outcomes in PD. A thorough search was conducted on PubMed focusing on studies published between 2018 and 2023 in English. The inclusion criteria encompassed clinical trials, randomized controlled trials, systematic reviews, meta-analyses, and reviews. The search strategy revolved around the implementation of MeSH terms related to safinamide and its impact on the quality of life in PD.

Conclusion

Our data strongly support the improving effect on QoL, reducing the disabling NMS reported in patients with PD.

Nanotechnology-empowered therapeutics targeting neurodegenerative diseases

Neurodegenerative diseases are posing pressing health issues due to the high prevalence among aging populations in the 21st century. They are evidenced by the progressive loss of neuronal function, often associated with neuronal necrosis and many related devastating complications. Nevertheless, effective therapeutical strategies to treat neurodegenerative diseases remain a tremendous challenge due to the multisystemic nature and limited drug delivery to the central nervous system. As a result, there is a pressing need to develop effective alternative therapeutics to manage the progression of neurodegenerative diseases. By utilizing the functional reconstructive materials and technologies with specific targeting ability at the nanoscale level, nanotechnology-empowered medicines can transform the therapeutic paradigms of neurodegenerative diseases with minimal systemic side effects. This review outlines the current applications and progresses of the nanotechnology-enabled drug delivery systems to enhance the therapeutic efficacy in treating neurodegenerative diseases. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Establishment of a sensitive UPLC-MS/MS method to quantify safinamide in rat plasma

A fast, simple, and sensitive ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established for the quantification of safinamide in rat plasma. Plasma samples were treated with acetonitrile for protein precipitation, and diazepam was used as an internal standard (IS). The analytes were separated on an Acquity UPLC C18 (2.1 mm × 50 mm, 1.7 μm) chromatographic column with gradient elution using a mobile phase (0.1% formic acid-acetonitrile). Then, the eluates were detected by electrospray ionization (ESI) in positive ion mode. The analytes were quantified by multiple reaction monitoring (MRM) using the transition m/z 303.3→215.0 of safinamide and m/z 285.0→154.0 of IS. Safinamide had good linearity in the concentration range of 1.0-2000 ng/mL, and the lower limit of quantitation (LLOQ) was 1.0 ng/mL. The intra- and inter-day precision and accuracy of safinamide were less than 7.63%, while the average recovery rate was 92.98%-100.29%. The method was validated to be stable and had low noise, short chromatographic run time, wide linear range, small sample volumes, low sample injection volumes, and high sensitivity. Therefore, it can be used in pharmacokinetics and preclinical and clinical studies.

Evaluation of developmental toxicity of safinamide in zebrafish larvae (Danio rerio)

Monoamine oxidase-B (MAO-B), as a principal metabolizing enzyme, plays important roles in the metabolism of catecholamines and xenobiotics in the central nervous system and peripheral tissues. Safinamide, the third-generation reversible MAO-B inhibitor, has potential to alleviate many neurological diseases such as Parkinson's disease (PD) and depression. Exposure to clinical psychotropic drugs often has adverse effects on fetuses. Currently, a variety of studies of safinamide focus on its curative effect and pharmacological effect, while its side effect of embryonic development is barely studied. In this study, we used zebrafish as a model to evaluate the embryonic developmental toxicity of safinamide. Our results revealed that higher concentrations (30 μM) of safinamide treatment caused a decrease in hatching rate and an increase in malformation and mortality in zebrafish larvae. Meanwhile, we observed that lower safinamide exposure (10 μM) increased the body length of zebrafish larvae and resulted in hyperactivity-like behaviors. In addition, an increased trend in dopamine (DA) level was found in 3.3 μM and 10 μM safinamide-exposed groups. Transcriptome analysis identified that safinamide exposure may disturb a variety of physiological processes such as neuroactive ligand-receptor interaction signaling pathway. In summary, our study reveals that safinamide may cause developmental defects in zebrafish larvae and provides insights into its toxic reactions in early develoment.

Therapeutic and Neuroprotective Effects of Bushen Jianpi Decoction on a Rotenone-Induced Rat Model of Parkinson’s Disease

Parkinson’s disease (PD) is an age-related neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra (SN) pars compacta. Dopamine (DA) replacement therapy is one of the most effective drug treatments for PD; however, long-term levodopa treatment can lead to various side effects that negatively impact the quality of life of patients. Therefore, finding safe and effective alternative drugs to treat PD is of clinical importance. The Bushen-Jianpi decoction (BSJPD) was derived from classic traditional Chinese medicine and has been shown to be effective in the treatment of PD. This study explored the effects and mechanisms of action of BSJPD in PD. In our study, rats were randomly divided into six groups: the vehicle group, rotenone (ROT) + Saline group, ROT + low-dose BSJPD group, ROT + high-dose BSJPD group, ROT + Madopar group, and ROT + low-dose BSJPD + Madopar group. Treatment was administered to the rats once a day for 28 days, and behavioral tests were assessed. Tyrosine hydroxylase (TH), catechol-O-methyltransferase (COMT), monoamine oxidase B (MAO-B), dopa decarboxylase (DDC), alpha-synuclein (α-syn), and heme oxygenase-1 (HO-1) levels were detected. Our results show that BSJPD increases the body weight of rats, improves their motor coordination, reverses decreasing TH levels in the SN, and increases the expression level of DDC and HO-1 in the striatum (ST), but it fails to affect TH levels in the ST in the PD model. In addition, BSJPD reduced the expression of MAO-B in the ST in the PD model, but it did not have a significant effect on COMT. Rather, COMT in the plasma and liver increased in the low-dose BSJPD treatment group. Upregulation of α-syn in the PD model was also observed, but BSJPD has shown no obvious effect to clear it. Our results suggest that BSJPD exhibits a therapeutic effect on PD and may play a neuroprotective role by regulating HO-1 expression and participating in the metabolic process of DA.

Green Spectrophotometric Platforms for Resolving Overlapped Spectral Signals of Recently Approved Antiparkinsonian Drug (Safinamide) in the Presence of Its Synthetic Precursor (4-Hydroxybenzaldehyde): Applying Ecological Appraisal and Comparative Statistical Studies

BACKGROUND

Safinamide, a highly specific inhibitor of monoamine oxidase B, is a new approved prodigious therapy used to cure Parkinson's disease (PD).

OBJECTIVE

Before marketing and selling a medicine, manufacturers must guarantee that the manufacturing process is consistent by monitoring levels of process-related chemicals and drug contaminants. Therefore, five precise, fast, and accurate spectrophotometric techniques were employed and evaluated for the simultaneous measurement of safinamide and its synthetic precursor, 4-hydroxybenzaldehyde.

METHODS

The first derivative, derivative ratio, ratio difference, dual wavelength, and Fourier self-deconvolution methods worked well to resolve spectral overlap of safinamide and its synthetic precursor, 4-hydroxybenzaldehyde.

RESULTS

Safinamide detection limits ranged from 0.598 to 1.315 µg/mL, whereas the 4-hydroxybenzaldehyde detection limit was found to be as low as 0.327 µg/mL.

CONCLUSION

According to International Council for Harmonisation (ICH) criteria, all procedures were verified and confirmed to be accurate, robust, repeatable, and precise within reasonable range. No considerable variation was found when comparing the outcomes of the suggested approaches to the findings of previously published methods. The ecological value of established methods was measured: the national environmental methods index (NEMI), the analytical eco-scale, the analytical greenness metric (AGREE), and the green analytical process index (GAPI) were used.

HIGHLIGHTS

This is the first spectrophotometric determination of safinamide drug in the presence of its synthetic precursor. Five simple and efficient spectrophotometric approaches were employed to determine a newly approved antiparkinsonian drug in the presence of its synthetic precursor simultaneously. Ecological appraisal was performed for the developed methods using four assessment tools.

The current state of amyloidosis therapeutics and the potential role of fluorine in their treatment

Amyloidosis, commonly known as amyloid-associated diseases, is characterized by improperly folded proteins accumulating in tissues and eventually causing organ damage, which is linked to several disorders ranging from neurodegenerative to peripheral diseases. It has an enormous societal and financial impact on the global health sector. Due to the complexity of protein misfolding and intertwined aggregation, there are no effective disease-modifying medications at present, and the condition is likely mis/non-diagnosed half of the time. Nonetheless, over the last two decades, substantial research into aggregation processes has revealed the possibilities of new intervention approaches. On the other hand, fluorine has been a rising star in therapeutic development for numerous neurodegenerative illnesses and other peripheral diseases. In this study, we revised and emphasized the possible significance of fluorine-modified therapeutic molecules and fluorine-modified nanoparticles (NPs) in the modulation of amyloidogenic proteins, including insulin, amyloid beta peptide (Aβ), prion protein (PrP), transthyretin (TTR) and Huntingtin (htt).

Nardosinone regulates the slc38a2 gene to alleviate Parkinson's symptoms in rats through the GABAergic synaptic and cAMP pathways

In a rotenone-induced Parkinson's disease (PD) rat model, behavioral investigation, pathological examination, inflammatory factor analysis, and mitochondrial structure and function investigation verified the anti-PD efficacy of nardosinone. A combined transcriptome and proteome analysis proposed that the anti-PD target of nardosinone is the slc38a2 gene and may involve the GABAergic synaptic pathway and cAMP-signaling pathway. Analysis of targeted slc38a2 knockout cells and expression of key enzyme-encoding genes in both pathways verified the target and pathways proposed by the 'omics analysis. This further confirms that nardosinone can regulate the slc38a2 gene, a potential new target for the treatment of Parkinson's disease, and plays an anti-PD role through the GABAergic synaptic and cAMP pathways.

Monoamine Oxidase-B Inhibitors for the Treatment of Parkinson's Disease: Past, Present, and Future

Monoamine oxidase-B (MAO-B) inhibitors are commonly used for the symptomatic treatment of Parkinson’s disease (PD). MAO-B inhibitor monotherapy has been shown to be effective and safe for the treatment of early-stage PD, while MAO-B inhibitors as adjuvant drugs have been widely applied for the treatment of the advanced stages of the illness. MAO-B inhibitors can effectively improve patients’ motor and non-motor symptoms, reduce “OFF” time, and may potentially prevent/delay disease progression. In this review, we discuss the effects of MAO-B inhibitors on motor and non-motor symptoms in PD patients, their mechanism of action, and the future development of MAO-B inhibitor therapy.

Indoles and 1-(3-(benzyloxy)benzyl)piperazines: Reversible and selective monoamine oxidase B inhibitors identified by screening an in-house compound library

The therapeutic indications for monoamine oxidases A and B (MAO-A and MAO-B) inhibitors that have emerged from biological studies on animal and cellular models of neurological and oncological diseases have focused drug discovery projects upon identifying reversible MAO inhibitors. Screening of our in-house academic compound library identified two hit compounds that inhibit MAO-B with IC₅₀ values in micromolar range. Two series of indole (23 analogues) and 3-(benzyloxy)benzyl)piperazine (16 analogues) MAO-B inhibitors were derived from hits, and screened for their structure-activity relationships. Both series yielded low micromolar selective inhibitors of human MAO-B, namely indole 2 (IC₅₀ = 12.63 ± 1.21 µM) and piperazine 39 (IC₅₀ = 19.25 ± 4.89 µM), which is comparable to selective MAO-B inhibitor isatin (IC₅₀ = 6.10 ± 2.81 µM), yet less potent in comparison to safinamide (IC₅₀ = 0.029 ± 0.002 µM). Selective MAO-B inhibitors 2, 14, 38 and 39 exhibited favourable permeation of the blood-brain barrier and low cytotoxicity in the human neuroblastoma cell line SH-SY5Y.

From regenerative strategies to pharmacological approaches: can we fine-tune treatment for Parkinson's disease?

Parkinson's disease is the second most prevalent neurodegenerative disorder worldwide. Clinically, it is characterized by severe motor complications caused by progressive degeneration of dopaminergic neurons. Current treatment is focused on mitigating the symptoms through the administration of levodopa, rather than on preventing dopaminergic neuronal damage. Therefore, the use and development of neuroprotective/disease-modifying strategies is an absolute need that can lead to promising gains on translational research of Parkinson's disease. For instance, N-acetylcysteine, a natural compound with strong antioxidant effects, has been shown to modulate oxidative stress, preventing dopamine-induced cell death. Despite the evidence of neuroprotective and modulatory effects of this drug, as far as we know, it does not induce per se any regenerative process. Therefore, it would be of interest to combine the latter with innovative therapies that induce dopaminergic neurons repair or even differentiation, as stem cell-based strategies. Stem cells secretome has been proposed as a promising therapeutic approach for Parkinson's disease, given its ability to modulate cell viability/preservation of dopaminergic neurons. Such approach represents a shift in the paradigm, showing that cell-transplantation free therapies based on the use of stem cells secretome may represent a potential alternative for regenerative medicine of Parkinson's disease. Thus, in this review, we address the current understanding of the potential combination of stem cell free-based strategies and neuroprotective/disease-modifying strategies as a new paradigm for the treatment of central nervous system neurodegenerative diseases, like Parkinson's disease.

Neuroprotective effect of bone marrow-derived mesenchymal stem cell secretome in 6-OHDA-induced Parkinson's disease

Aim: The aim of the study was to evaluate the neuroprotective effect of bone marrow stem cell secretome in the 6-hydroxydopamine (6-OHDA) model of Parkinson's disease. Materials & methods: Secretome prepared from mesenchymal stem cells of 3-month-old rats was injected daily for 7 days between days 7 and 14 after 6-OHDA administration. After 14 days, various neurobehavioral parameters were conducted. These behavioral parameters were further correlated with biochemical and molecular findings. Results & conclusion: Impaired neurobehavioral parameters and increased inflammatory, oxidative stress and apoptotic markers in the 6-OHDA group were significantly modulated by secretome-treated rats. In conclusion, mesenchymal stem cell-derived secretome could be further explored for the management of Parkinson's disease.

A Two Hour Synthesis of the Anti-Parkinson Drug Safinamide Methanesulfonate

The critical moment of the COVID-19 outbreak requires a real-time supply of therapeutic agents. Thus, time economy in the synthesis of biologically active compounds has become increasingly decisive. In this work, we developed a two hour synthesis of the anti-Parkinson drug safinamide methanesulfonate in four steps with a 64% overall yield. Microwave irradiation was used in the first three steps in a one-pot fashion. In fact, the protocol can provide safinamide free base in one hour without a chromatographic purification step. Also, green solvents such as methanol and ethyl acetate are used.

Nardosinone Alleviates Parkinson's Disease Symptoms in Mice by Regulating Dopamine D2 Receptor

Nardostachyos Radix et Rhizoma (nardostachys) is the root and rhizome of Nardostachys jatamansi DC. Recent studies have shown that nardostachys may exert an anti-PD effect. In this study, the UHPLC-LTQ-Orbitrap-MS method was used to analyze the brain components of nardostachys in rats. Based on the results of UHPLC-LTQ-Orbitrap-MS analysis, nardosinone was identified to be the most effective anti-PD compound in nardostachys. To further verify this inference, a mouse PD model was established and the effect of nardosinone on PD mice was determined using classic behavioral tests. The results showed that nardosinone was indeed effective for relieving PD symptoms in mice. Moreover, network pharmacology analysis was used to elucidate the mechanism underlying the anti-PD effect of nardosinone. Dopamine receptor D2 (DRD2) was identified as the key target of nardosinone-PD interaction network, which was further verified by molecular docking and Western blotting. The results demonstrated that nardosinone and DRD2 could interact with each other. Furthermore, the expression level of DRD2 was decreased in the brain tissue of PD mice, and nardosinone could restore its expression to a certain extent. In conclusion, our findings suggest that nardosinone may reduce the motor and cognitive symptoms in the animal PD model by regulating DRD2 expression.

Fractionating stem cells secretome for Parkinson's disease modeling: Is it the whole better than the sum of its parts?

Human mesenchymal stem cells (hMSCs) secretome has been have been at the forefront of a new wave of possible therapeutic strategies for central nervous system neurodegenerative disorders, as Parkinson's disease (PD). While within its protein fraction, several promising proteins were already identified with therapeutic properties on PD, the potential of hMSCs-secretome vesicular fraction remains to be elucidated. Such highlighting is important, since hMSCs secretome-derived vesicles can act as biological nanoparticles with beneficial effects in different pathological contexts. Therefore, in this work, we have isolated hMSCs secretome vesicular fraction, and assessed their impact on neuronal survival, and differentiation on human neural progenitors' cells (hNPCs), and in a 6-hydroxydopamine (6-OHDA) rat model of PD when compared to hMSCs secretome (as a whole) and its protein derived fraction. From the results, we have found hMSCs vesicular fraction as polydispersity source of vesicles, which when applied in vitro was able to induce hNPCs differentiation at the same levels as the whole secretome, while the protein separated fraction was not able to induce such effect. In the context of PD, although distinct effects were observed, hMSCs secretome and its derived fractions displayed a positive impact on animals' motor and histological performance, thereby indicating that hMSCs secretome and its different fractions may impact different mechanisms and pathways. Overall, we concluded that the use of the secretome collected from hMSCs and its different fractions might be active modulators of different neuroregeneration mechanisms, which could open new therapeutical opportunities for their future use as a treatment for PD.

Safinamide in neurological disorders and beyond: Evidence from preclinical and clinical studies

The discovery and development of safinamide, an alpha-aminoamide, has been a valuable addition to the existing clinical management of Parkinson's disease (PD). The journey of safinamide dates back to the year 1983, when an alpha-aminoamide called milacemide showed a weak anticonvulsant activity. Milacemide was then structurally modified to give rise to safinamide, which in turn produced robust anticonvulsant activity. The underlying mechanism behind this action of safinamide is attributed to the inhibition of voltage gated calcium and sodium channels. Moreover, owing to the importance of ion channels in maintaining neuronal circuitry and neurotransmitter release, numerous studies explored the potential of safinamide in neurological diseases including PD, stroke, multiple sclerosis and neuromuscular disorders such as Duchenne muscular dystrophy and non-dystrophic myotonias. Nevertheless, evidence from multiple preclinical studies suggested a potent, selective and reversible inhibitory activity of safinamide against monoamine oxidase (MAO)-B enzyme which is responsible for degrading dopamine, a neurotransmitter primarily implicated in the pathophysiology of PD. Therefore, clinical studies were conducted to assess safety and efficacy of safinamide in PD. Indeed, results from various Phase 3 clinical trials suggested strong evidence of safinamide as an add-on therapy in controlling the exacerbation of PD. This review presents a thorough developmental history of safinamide in PD and provides comprehensive insight into plausible mechanisms via which safinamide can be explored in other neurological and muscular diseases.

Glial cells in Parkinson´s disease: protective or deleterious?

Glial cells have been identified more than 100 years ago, and are known to play a key role in the central nervous system (CNS) function. A recent piece of evidence is emerging showing that in addition to the capacity of CNS modulation and homeostasis, glial cells are also being looked like as a promising cell source not only to study CNS pathologies initiation and progression but also to the establishment and development of new therapeutic strategies. Thus, in the present review, we will discuss the current evidence regarding glial cells' contribution to neurodegenerative diseases as Parkinson's disease, providing cellular, molecular, functional, and behavioral data supporting its active role in disease initiation, progression, and treatment. As so, considering their functional relevance, glial cells may be important to the understanding of the underlying mechanisms regarding neuronal-glial networks in neurodegeneration/regeneration processes, which may open new research opportunities for their future use as a target or treatment in human clinical trials.

Pyrimido[1,2-b]indazole derivatives: Selective inhibitors of human monoamine oxidase B with neuroprotective activity

Structurally diverse heterotricyclic compounds are recognized as monoamine oxidase (MAO) inhibitors and thus represent an appealing scaffold in development and optimization of novel MAO inhibitors. Herein we explored the chemical space of pyrimido[1,2-b]indazoles as MAO inhibitors by preparing a small library of (hetero)aryl derivatives. An efficient synthetic strategy was developed starting from commercially available 1H-indazol-3-amines, which were converted to various 3-bromoheterotricyclic derivatives and further functionalized via Suzuki-Miyaura coupling reaction. Derivatives 4a-t selectively inhibited human MAO-B isoform in a reversible and competitive manner as confirmed by kinetic experiments and docking studies. Selected derivatives were not cytotoxic to neuroblastoma SH-SY5Y cells. Moreover, analogue 4i protected human neuroblastoma SH-SY5Y cells against 6-hydroxydopamine-induced cell death, which confirms the applicability of the pyrimido[1,2-b]indazoles as potential antiparkinsonian agents.

Neuroprotective and neuro-survival properties of safinamide against methamphetamine-induced neurodegeneration: Hypothetic possible role of BDNF/TrkB/PGC-1α signaling pathway and mitochondrial uncoupling protein -2(UCP-2)

Methamphetamine is a behavioral psychostimulant that has a high potential for misuse and induction of neurotoxicity. Safinamide is a novel inhibitor of monoamine oxidase B (MAOB) with neuroprotective properties. Methamphetamine abuse causes dysfunction in the respiratory chain of the mitochondria, but the specific signaling mechanism and role of the uncoupling protein-2(UCP-2) remain unclear. As we know, some indirect evidence indicates that neurodegeneration can be caused by inhibition of the brain-derived neurotrophic factor (BDNF) receptor, TrkB and its downstream signaling pathway, such as the PGC-1α protein. Neuroprotective strategies and approaches to the management, treatment or prevention of methamphetamine-induced neurodegeneration by modulating BDNF / TrkB / PGC-1α-UCP-2 can be considered as novel therapeutic approaches to these psychostimulant neurochemical and neurobehavioral approaches. Previous studies have shown that safinamide, a monoamine oxidase-B (MAOB) inhibitor, can function as a neuroprotective agent and inhibit the neurodegenerative process especially in Parkinson's disease but its impact on other neurodegenerative processes and drug-induced neurotoxicity remain unclear. Although there is some evidence that BDNF / TrkB / PGC-1α-UCP-2 signaling pathway and mitochondrial UCP-2 mediated safinamide induced neuroprotection but it's exact and precise mechanism of action and neuroprotective effects in neurodegenerative disorder and the protective properties against methamphetamine induced neurodegeneration and the role of BDNF / TrkB / PGC-1α signaling pathway and role of mitochondrial UCP-2 in this process have not yet been clarified. Therefore, in subjects addicted to methamphetamine, we hypothesized that safinamide will provide neuroprotection against methamphetamine-prompted neurodegeneration, and it appears that BDNF / TrkB / PGC-1α signaling pathway and mitochondrial UCP-2 are likely to play a critical role.

Effects of safinamide on pain in Parkinson's disease with motor fluctuations: an exploratory study

Pain is a common and disabling non-motor symptom (NMS) of Parkinson's disease (PD), which occurs through the course of the disease, often unrecognized and undertreated. For this study, we evaluated the efficacy and safety of safinamide to reduce pain in PD patients with motor fluctuations. A total of 13 PD patients with pain receiving safinamide (Xadago®, 100 mg/daily) were prospectively evaluated for 12 weeks. The primary outcome measures were changes in the total score of the King's Pain Scale for Parkinson's Disease (KPPS), Brief Pain Inventory (BPI) Intensity and Interference, and the Numeric Rating Scale (NRS). Secondary outcomes were the proportion of pain responders, changes in the Clinical Global Impression of Change (CGI), the Parkinson's disease Quality of Life 39 (PDQ39), the Unified Parkinson's Disease Rating Scale parts III and IV (UPDRS III and IV), and laser-evoked potentials (LEPs). LEPs were used to assess potential changes in the central processing of nociceptive inputs. The safety profile was evaluated based on the occurrence of treatment-emergent side effects and the dropout rate. After 12 weeks of add-on safinamide therapy, a significant improvement was noted in the primary (KPPS, BPI Intensity and interference, and NRS) and the secondary outcomes (UPDRS III, IV, CGI, and PDQ39). No significant changes in LEP complexes were observed. All patients completed the study and no treatment-emergent side effects were reported. Our preliminary findings suggest that safinamide 100 mg/day may be effective for the management of pain in PD patients with motor fluctuations and is safe. Further randomized controlled trials are needed to confirm its efficacy.

Preclinical Comparison of Stem Cells Secretome and Levodopa Application in a 6-Hydroxydopamine Rat Model of Parkinson's Disease

Parkinson's Disease (PD) is characterized by the massive loss of dopaminergic neurons, leading to the appearance of several motor impairments. Current pharmacological treatments, such as the use of levodopa, are yet unable to cure the disease. Therefore, there is a need for novel strategies, particularly those that can combine in an integrated manner neuroprotection and neuroregeneration properties. In vitro and in vivo models have recently revealed that the secretome of mesenchymal stem cells (MSCs) holds a promising potential for treating PD, given its effects on neural survival, proliferation, differentiation. In the present study, we aimed to access the impact of human bone marrow MSCs (hBM-MSCs) secretome in 6-hydroxydopamine (6-OHDA) PD model when compared to levodopa administration, by addressing animals' motor performance, and substantia nigra (SN), and striatum (STR) histological parameters by tyrosine hydroxylase (TH) expression. Results revealed that hBM-MSCs secretome per se appears to be a modulator of the dopaminergic system, enhancing TH-positive cells expression (e.g., dopaminergic neurons) and terminals both in the SN and STR when compared to the untreated group 6-OHDA. Such finding was positively correlated with a significant amelioration of the motor outcomes of 6-OHDA PD animals (assessed by the staircase test). Thus, the present findings support hBM-MSCs secretome administration as a potential therapeutic tool in treating PD, and although we suggest candidate molecules (Trx1, SEMA7A, UCHL1, PEDF, BDNF, Clusterin, SDF-1, CypA, CypB, Cys C, VEGF, DJ-1, Gal-1, GDNF, CDH2, IL-6, HSP27, PRDX1, UBE3A, MMP-2, and GDN) and possible mechanisms of hBM-MSCs secretome-mediated effects, further detailed studies are needed to carefully and clearly define which players may be responsible for its therapeutic actions. By doing so, it will be reasonable to presume that potential treatments that can, per se, or in combination modulate or slow PD may lead to a rational design of new therapeutic or adjuvant strategies for its functional modeling and repair.

Applications of fluorine-containing amino acids for drug design

Fluorine-containing amino acids are becoming increasingly prominent in new drugs due to two general trends in the modern pharmaceutical industry. Firstly, the growing acceptance of peptides and modified peptides as drugs; and secondly, fluorine editing has become a prevalent protocol in drug-candidate optimization. Accordingly, fluorine-containing amino acids represent one of the more promising and rapidly developing areas of research in organic, bio-organic and medicinal chemistry. The goal of this Review article is to highlight the current state-of-the-art in this area by profiling 42 selected compounds that combine fluorine and amino acid structural elements. The compounds under discussion represent pharmaceutical drugs currently on the market, or in clinical trials as well as examples of drug-candidates that although withdrawn from development had a significant impact on the progress of medicinal chemistry and/or provided a deeper understanding of the nature and mechanism of biological action. For each compound, we present features of biological activity, a brief history of the design principles and the development of the synthetic approach, focusing on the source of tailor-made amino acid structures and fluorination methods. General aspects of the medicinal chemistry of fluorine-containing amino acids and synthetic methodology are briefly discussed.

The current status of pharmacotherapy for the treatment of Parkinson's disease: transition from single-target to multitarget therapy

Parkinson's disease (PD) is a neurodegenerative disorder characterized by degeneration of dopaminergic neurons. Motor features such as tremor, rigidity, bradykinesia and postural instability are common traits of PD. Current treatment options provide symptomatic relief to the condition but are unable to reverse disease progression. The conventional single-target therapeutic approach might not always induce the desired effect owing to the multifactorial nature of PD. Hence, multitarget strategies have been proposed to simultaneously target multiple proteins involved in the development of PD. Herein, we provide an overview of the pathogenesis of PD and the current pharmacotherapies. Furthermore, rationales and examples of multitarget approaches that have been tested in preclinical trials for the treatment of PD are also discussed.

Mesenchymal Stem Cells-derived Exosomes: A New Possible Therapeutic Strategy for Parkinson's Disease?

Parkinson’s disease (PD) is the second most prevalent neurodegenerative disorder worldwide. Clinically, it is characterized by severe motor complications caused by a progressive degeneration of dopaminergic neurons (DAn) and dopamine loss. Current treatment is focused on mitigating the symptoms through administration of levodopa, rather than on preventing DAn damage. Therefore, the use and development of neuroprotective/disease-modifying strategies is an absolute need, which can lead to promising gains on PD translational research. Mesenchymal stem cells (MSCs)–derived exosomes have been proposed as a promising therapeutic tool, since it has been demonstrated that they can act as biological nanoparticles with beneficial effects in different pathological conditions, including PD. Thus, considering their potential protective action in lesioned sites, MSCs-derived exosomes might also be active modulators of the neuroregeneration processes, opening a door for their future use as therapeutical strategies in human clinical trials. Therefore, in this review, we analyze the current understanding of MSCs-derived exosomes as a new possible therapeutic strategy for PD, by providing an overview about the potential role of miRNAs in the cellular and molecular basis of PD.

4-tert-Pentylphenoxyalkyl derivatives - Histamine H3 receptor ligands and monoamine oxidase B inhibitors

The synthesis and biological activity of 4-tert-pentylphenoxypropyl derivatives are described in this manuscript. All compounds (except one) showed human histamine H₃ receptor affinity with K_i values below 760 nM. The inhibitory activity toward human monoamine oxidase B (hMAO B) was evaluated using a fluorometric Amplex-Red assay, and most of the compounds were effective in the submicromolar range. Among them, 1-(3-(4-tert-pPentylphenoxy)propyl)pyrrolidine (5) exhibited hMAO B inhibitory activity with an IC₅₀ value of 4.5 nM. In addition, hMAO B inhibition by 5 was shown to be non-competitive and reversible. Further, recently described potent histamine H₃ receptor ligands - 4-tert-pentylphenoxyalkyl derivatives (with a 4-8 carbon spacer) - were evaluated for hMAO B inhibitory activity, and some of them displayed activity in the submicromolar range. Selected compounds were also tested for human MAO A (hMAO A) inhibitory potencies and exhibited no activity. Moreover, molecular modeling studies were carried out for tested compounds to explain their molecular mechanism of hMAO B inhibition and the selectivity of compounds for hMAO B over hMAO A.

Monoamine oxidase inhibitors, and iron chelators in depressive illness and neurodegenerative diseases

In early 1920s, tyramine oxidase was discovered that metabolized tyramine and in 1933 Blaschko demonstrated that this enzyme also metabolized adrenaline, noradrenaline and dopamine. Zeller gave it the name monoamine oxidase (MAO) to distinguish it from the enzyme that oxidatively deaminated diamines. MAO was recognized as an enzyme of crucial interest to pharmacologists because it catalyzed the major inactivation pathway for the catecholamines (and, later, 5-hydroxytryptamine, as well). Within the few decade, the inhibitors of MAO were discovered and introduced for the treatment of depressive illness which was established clinically. However, the first clinical use exposed serious side effects, pharmacological interest in, and investigation of, MAO continued, resulting in the characterization of two forms, distinct forms, MAO-A and -B, and selective inhibitors for them. Selective inhibitors of MAO-B (selegiline, rasagiline and safinamide) have found a therapeutic role in the treatment of Parkinson's disease and reversible inhibitors of MAO-A offered antidepressant activity without the serious side effects of the earlier nonselective MAO inhibitors. Subsequent molecular pharmacological have also generated the concept of neuroprotection, reflecting the possibility of slowing, halting and maybe reversing, neurodegeneration in Parkinson's or Alzheimer's diseases. Increased levels of oxidative stress through the accumulation of iron in the Parkinsonian and Alzheimer brains has been suggested to be critical for the initiation and progress of neurodegeneration. Selective inhibition of brain MAO could contribute importantly to lowering such stress, preventing the formation of hydrogen peroxide. Interaction of Iron with hydrogen peroxide and lead to Fenton reaction and production of the most reactive radical, namely hydroxyl radical. There are complex interactions between free iron levels in brain and MAO, and cascade of neurotoxic events may have practical outcomes for depressive disorders and neurodegenerative diseases. As consequence recent novel therapeutic drugs for neurodegenerative diseases has led to the development of multi target drugs, that possess selective brain MAO A and B inhibitory moiety, iron chelating and antioxidant activities and the ability to increase brain levels of endogenous neurotrophins, such as BDNF, GDNF VEGF and erythropoietin and induce mitochondrial biogenesis.

Interactions of endocannabinoid virodhamine and related analogs with human monoamine oxidase-A and -B

The endocannabinoid system plays an important role in the pathophysiology of various neurological disorders, such as anxiety, depression, neurodegenerative diseases, and schizophrenia; however, little information is available on the coupling of the endocannabinoid system with the monoaminergic systems in the brain. In the present study, we tested four endocannabinoids and two anandamide analogs for inhibition of recombinant human MAO-A and -B (monoamine oxidase). Virodhamine inhibited both MAO-A and -B (IC50 values of 38.70 and 0.71 μM, respectively) with ∼55-fold greater inhibition of MAO-B. Two other endocannabinoids (noladin ether and anandamide) also showed good inhibition of MAO-B with IC50 values of 18.18 and 39.98 μM, respectively. Virodhamine was further evaluated for kinetic characteristics and mechanism of inhibition of human MAO-B. Virodhamine inhibited MAO-B (Ki value of 0.258 ± 0.037 μM) through a mixed mechanism/irreversible binding and showed a time-dependent irreversible mechanism. Treatment of Neuroscreen-1 (NS-1) cells with virodhamine produced significant inhibition of MAO activity. This observation confirms potential uptake of virodhamine by neuronal cells. A molecular modeling study of virodhamine with MAO-B and its cofactor flavin adenine dinucleotide (FAD) predicted virodhamine's terminal -NH2 group to be positioned near the N5 position of FAD, but for docking to MAO-A, virodhamine's terminal -NH2 group was far away (∼6.52 Å) from the N5 position of FAD, and encountered bad contacts with nearby water molecules. This difference could explain virodhamine's higher potency and preference for MAO-B. The binding free energies for the computationally-predicted poses also showed that virodhamine was selective for MAO-B. These findings suggest potential therapeutic applications of virodhamine for the treatment of neurological disorders.