Serum concentration and clinical significance of brain-derived neurotrophic factor in patients with Parkinson's disease or essential tremor

Serum concentrations of BDNF in adolescents with metabolic syndrome: a case-control study between normal - BMI adolescents and adolescents with obesity

Brain-Derived Neurotrophic Factor (BDNF) has been linked to various conditions of the cardiovascular and nervous systems. Scarce data exist about the concentrations of BDNF in children and adolescents in relation with obesity and metabolic syndrome (MetS). The aim of this study was to examine the serum BDNF concentrations in adolescents with metabolic syndrome and according to their body mass index (BMI) status. This was a case-control study, assessing BDNF concentrations between adolescents with MetS (with obesity vs. normal-BMI), in relation to sex, anthropometric, metabolic and endocrine parameters. Participants included male and female adolescents, whose anthropometric and metabolic panel, as well as serum BDNF concentrations were measured. A total of 59 adolescents (obesity: 29; normal-BMI: 30) were included in the study. Increased serum BDNF concentrations were observed in MetS adolescents with obesity when compared with normal-BMI adolescents (p < 0.001). Males exhibited higher concentrations of BDNF than females (p = 0.045). The sample was further divided into four categories by sex and BMI status, with normal-BMI females exhibiting significantly lower BDNF concentrations than females and males with obesity(p = 0.005). In the entire study sample, serum BDNF concentrations correlated positively with BMI z-scores, however, this statistical significance was preserved only in the females of the sample. No statistical difference was observed between males of different BMI z-scores categories.  Conclusion: Obesity appeared as a major factor for increased serum BDNF concentrations in adolescents with MetS (vs. normal-BMI), with a higher impact on BDNF concentrations in females than males. What is Known: • The brain-derived neurotrophic factor (BDNF) is involved in metabolic syndrome in adults but data in adolescents are scarce. What is New: • Obesity (vs. normal BMI) was a major factor for increased serum BDNF in adolescents with metabolic syndrome. • Obesity had a higher impact on BDNF concentrations in females than males with metabolic syndrome.

Alterations of Plasmatic Biomarkers of Neurodegeneration in Mucopolysaccharidosis Type II Patients Under Enzyme Replacement Therapy

Mucopolysaccharidosis type II (MPS II) is a disorder caused by a deficient activity of iduronate-2-sulfatase, a lysosomal enzyme responsible for degrading glycosaminoglycans (GAGs). The abnormal storage of GAGs within lysosomes disrupts cellular homeostasis and leads to a severe symptomatology. Patients present neuropsychiatric impairment characterized by mental retardation and impaired cognition. The aim of this study was to quantify four neurodegeneration biomarkers in plasma: brain-derived neurotrophic factor (BDNF), platelet-derived growth factor (PDGF-AA), neural cell adhesion molecule (NCAM) and cathepsin-D, as well as to identify possible correlations with urinary GAGs in seven patients undergoing treatment with ERT (Elaprase® 0.5 mg/kg of body weight). Patients with both severe and attenuated forms of MPS II showed signs of neurodegeneration in neuroimaging exams. Patients have a decrease in BDNF and PDGF-AA concentrations, and an increase in NCAM level compared to controls. No alterations in cathepsin-D concentration were seen. GAGs levels were higher in patients than in controls, but no significant correlations between GAGs and biomarkers were observed. These results evidence that patients have neurodegeneration and that monitoring these biomarkers might be useful for assessing this process. To this date, this is the first work to analyze these plasmatic markers of neurodegeneration in patients.

Combating Dopaminergic Neurodegeneration in Parkinson's Disease through Nanovesicle Technology

Parkinson's disease (PD) is characterized by dopaminergic neurodegeneration, resulting in dopamine depletion and motor behavior deficits. Since the discovery of L-DOPA, it has been the most prescribed drug for symptomatic relief in PD, whose prolonged use, however, causes undesirable motor fluctuations like dyskinesia and dystonia. Further, therapeutics targeting the pathological hallmarks of PD including α-synuclein aggregation, oxidative stress, neuroinflammation, and autophagy impairment have also been developed, yet PD treatment is a largely unmet success. The inception of the nanovesicle-based drug delivery approach over the past few decades brings add-on advantages to the therapeutic strategies for PD treatment in which nanovesicles (basically phospholipid-containing artificial structures) are used to load and deliver drugs to the target site of the body. The present review narrates the characteristic features of nanovesicles including their blood-brain barrier permeability and ability to reach dopaminergic neurons of the brain and finally discusses the current status of this technology in the treatment of PD. From the review, it becomes evident that with the assistance of nanovesicle technology, the therapeutic efficacy of anti-PD pharmaceuticals, phyto-compounds, as well as that of nucleic acids targeting α-synuclein aggregation gained a significant increment. Furthermore, owing to the multiple drug-carrying abilities of nanovesicles, combination therapy targeting multiple pathogenic events of PD has also found success in preclinical studies and will plausibly lead to effective treatment strategies in the near future.

The Role of BDNF as a Biomarker in Cognitive and Sensory Neurodegeneration

Brain-derived neurotrophic factor (BDNF) has a crucial function in the central nervous system and in sensory structures including olfactory and auditory systems. Many studies have highlighted the protective effects of BDNF in the brain, showing how it can promote neuronal growth and survival and modulate synaptic plasticity. On the other hand, conflicting data about BDNF expression and functions in the cochlear and in olfactory structures have been reported. Several clinical and experimental research studies showed alterations in BDNF levels in neurodegenerative diseases affecting the central and peripheral nervous system, suggesting that BDNF can be a promising biomarker in most neurodegenerative conditions, including Alzheimer's disease, shearing loss, or olfactory impairment. Here, we summarize current research concerning BDNF functions in brain and in sensory domains (olfaction and hearing), focusing on the effects of the BDNF/TrkB signalling pathway activation in both physiological and pathological conditions. Finally, we review significant studies highlighting the possibility to target BDNF as a biomarker in early diagnosis of sensory and cognitive neurodegeneration, opening new opportunities to develop effective therapeutic strategies aimed to counteract neurodegeneration.

Molecular profile and peripheral markers of neurodegeneration in patients with Niemann-Pick type C: Decrease in Plasminogen Activator Inhibitor type 1 and Platelet-Derived Growth Factor type AA

Niemann-Pick type C1 (NPC1) is a fatal inherited disease, caused by pathogenic variants in NPC1 gene, which leads to intracellular accumulation of non-esterified cholesterol and glycosphingolipids. This accumulation leads to a wide range of clinical manifestations, including neurological and cognitive impairment as well as psychiatric disorders. The pathophysiology of cerebral damage involves loss of Purkinje cells, synaptic disturbance, and demyelination. Miglustat, a reversible inhibitor of glucosylceramide synthase, is an approved treatment for NPC1 and can slow neurological damage. The aim of this study was to assess the levels of peripheric neurodegeneration biomarkers of NPC1 patients, namely brain-derived neurotrophic factor (BDNF), platelet-derived growth factors (PDGF-AA and PDGF-AB/BB), neural cell adhesion molecule (NCAM), PAI-1 Total and Cathepsin-D, as well as the levels of cholestane-3β,5α,6β-triol (3β,5α,6β-triol), a biomarker for NPC1. Molecular analysis of the NPC1 patients under study was performed by next generation sequencing (NGS) in cultured fibroblasts. We observed that NPC1 patients treated with miglustat have a significant decrease in PAI-1 total and PDGF-AA concentrations, and no alteration in BDNF, NCAM, PDGF-AB/BB and Cathepsin D. We also found that NPC1 patients treated with miglustat have normalized levels of 3β,5α,6β-triol. The molecular analysis showed four described mutations, and for two patients was not possible to identify the second mutated allele. Our results indicate that the decrease of PAI-1 and PDGF-AA in NPC1 patients could be involved in the pathophysiology of this disease. This is the first work to analyze those plasmatic markers of neurodegenerative processes in NPC1 patients.

Empagliflozin enhances neuroplasticity in rotenone-induced parkinsonism: Role of BDNF, CREB and Npas4

AIMS

Parkinsonism is characterized by degeneration of dopaminergic neurons and impairment in neuroplasticity. Empagliflozin (EMPA) is an anti-diabetic drug that has been shown to improve cognitive dysfunctions and exerted antioxidant and anti-inflammatory effects in different models. This study aimed to determine the neuroprotective effects of EMPA against rotenone (ROT)-induced parkinsonism.

MAIN METHODS

ROT (1.5 mg/kg) was injected subcutaneously three times per week for two successive weeks. Mice were treated with EMPA (3 and 10 mg/kg, orally) for one week prior ROT administration and for another two weeks along with ROT. After that, motor functions and histopathological changes were assessed, and brains were isolated for biochemical analyses and immunohistochemical investigation.

KEY FINDINGS

Results indicated that, in a dose dependent manner, EMPA improved motor functions and histopathological changes induced by ROT, increased brain content of reduced glutathione (GSH), dopamine (DA), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), nuclear factor erythroid 2-related factor 2 (Nrf2), inositol trisphosphate (IP3), calcium (Ca²⁺), calcium/calmodulin-dependent protein kinase type IV (CaMKIV) and phospho-Protein kinase B (p-Akt) levels compared to ROT group. Additionally, EMPA decreased the levels of malondialdehyde (MDA), and tumor necrosis factor-α (TNF-α), and inactivated glycogen synthase kinase-3 beta (GSK-3β). Improvement in neuroplasticity was also observed indicated by elevation in brain derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB), and neuronal PAS domain Protein 4 (Npas4).

SIGNIFICANCE

EMPA improved motor functions possibly through improving neuroplasticity markers and antioxidant, anti-inflammatory, and neuroprotective effects in a dose dependent manner.

Effects of nordic walking exercise on gait, motor/non-motor symptoms, and serum brain-derived neurotrophic factor in individuals with Parkinson's disease

Objective

The primary purpose of this study was to investigate the immediate and long-term effects of Nordic Walking (NW) exercise on walking function, motor/non-motor Parkinson's Disease (PD) symptoms, and serum brain-derived neurotrophic factor (BDNF) in persons with idiopathic PD.

Methods

Twelve community-dwelling participants with mild to moderate idiopathic PD and varied degrees of gait dysfunction were recruited for this prospective, repeated measures design that examined clinical measures and BDNF levels at baseline (T0), post-intervention (T1) and 3-month follow-up (T2). Participants engaged in 6 weeks of supervised NW exercise training with individualized instruction, followed by 14 weeks of independent NW exercise with remote coaching. Outcome measurements included daily step counts, 6-Minute Walk Test (6-MinWT), 10-Meter Walk Test (10MWT), spatiotemporalparameters, Timed Up and Go Test (TUG), dual-task TUG, Revised-Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Revised-Freezing of Gait Questionnaire, MDS-Nonmotor Symptom scale (NMS), Parkinson's Fatigue Scale, and serum BDNF levels. The Friedman test with post hoc Wilcoxon sign-ranked pairwise comparisons were used to compare baseline to T1, baseline to T2, and T1 to T2 timepoints with a Benjamini-Hockberg correction applied.

Results

Statistically significant improvements found post-training and retained at 3-month follow-up included 6-MinWT, daily step count, 10mWT, MDS-UPDRS, and TUG with effect sizes of 0.57 to 1.03. Serum BDNF at T2 was significantly greater than T0 and T1. Although no statistically significant improvements were observed in the MDS-NMS, 9 of 12 participants had improved non-motor symptoms. There was good adherence, sustained independent exercise engagement, and no adverse events over the 5-month study duration.

Conclusions

This study demonstrated that NW exercise was a safe, feasible, and sustainable mode of aerobic exercise for this sample of participants with varied Parkinson's disease duration and severity. Following an individualized and progressive NW training intervention, significant improvements in walking function, daily activity level, and motor function were observed. Following the supervised NW training phase, independent three-month engagement in NW exercise was sustained with long-term retention of these clinical improvements and an increase in serum BDNF levels over this five-month NW exercise trial.

Impact

Nordic walking exercise may be a safe, feasible and sustainable mode of independent exercise for improving daily ambulatory activity, gait and motor function, and serum BDNF in individuals with mild to moderate PD with varied gait abilities.

Clinical Trials Registry ID

20-101-H.

New Frontiers in Neurodegeneration and Regeneration Associated with Brain-Derived Neurotrophic Factor and the rs6265 Single Nucleotide Polymorphism

Brain-derived neurotrophic factor is an extensively studied neurotrophin implicated in the pathology of multiple neurodegenerative and psychiatric disorders including, but not limited to, Parkinson’s disease, Alzheimer’s disease, Huntington’s disease, traumatic brain injury, major de-pressive disorder, and schizophrenia. Here we provide a brief summary of current knowledge on the role of BDNF and the common human single nucleotide polymorphism, rs6265, in driving the pathogenesis and rehabilitation in these disorders, as well as the status of BDNF-targeted therapies. A common trend has emerged correlating low BDNF levels, either detected within the central nervous system or peripherally, to disease states, suggesting that BDNF replacement therapies may hold clinical promise. In addition, we introduce evidence for a distinct role of the BDNF pro-peptide as a biologically active ligand and the need for continuing studies on its neurological function outside of that as a molecular chaperone. Finally, we highlight the latest research describing the role of rs6265 expression in mechanisms of neurodegeneration as well as paradoxical advances in the understanding of this genetic variant in neuroregeneration. All of this is discussed in the context of personalized medicine, acknowledging there is no “one size fits all” therapy for neurodegenerative or psychiatric disorders and that continued study of the multiple BDNF isoforms and genetic variants represents an avenue for discovery ripe with therapeutic potential.

A Single Domain Shark Antibody Targeting the Transferrin Receptor 1 Delivers a TrkB Agonist Antibody to the Brain and Provides Full Neuroprotection in a Mouse Model of Parkinson’s Disease

Single domain shark antibodies that bind to the transferrin receptor 1 (TfR1) on brain endothelial cells have been used to shuttle antibodies and other cargos across the blood brain barrier (BBB) to the brain. For these studies the TXB4 brain shuttle was fused to a TrkB neurotrophin receptor agonist antibody. The TXB4-TrkB fusion retained potent agonist activity at its cognate receptor and after systemic administration showed a 12-fold increase in brain levels over the unmodified antibody. Only the TXB4-TrkB antibody fusion was detected within the brain and localized to TrkB positive cells in the cortex and tyrosine hydroxylase (TH) positive dopaminergic neurons in the substantia nigra pars compacta (SNc), where it was associated with activated ERK1/2 signaling. When tested in the 6-hydroxydopamine (6-OHDA) mouse model of Parkinson’s disease (PD), TXB4-TrkB, but not the unmodified antibody, completely prevented the 6-OHDA induced death of TH positive neurons in the SNc. In conclusion, the fusion of the TXB4 brain shuttle allows a TrkB agonist antibody to reach neuroprotective concentrations in the brain parenchyma following systemic administration.

Brain-Derived Neurotropic Factor in Neurodegenerative Disorders

Globally, neurodegenerative diseases cause a significant degree of disability and distress. Brain-derived neurotrophic factor (BDNF), primarily found in the brain, has a substantial role in the development and maintenance of various nerve roles and is associated with the family of neurotrophins, including neuronal growth factor (NGF), neurotrophin-3 (NT-3) and neurotrophin-4/5 (NT-4/5). BDNF has affinity with tropomyosin receptor kinase B (TrKB), which is found in the brain in large amounts and is expressed in several cells. Several studies have shown that decrease in BDNF causes an imbalance in neuronal functioning and survival. Moreover, BDNF has several important roles, such as improving synaptic plasticity and contributing to long-lasting memory formation. BDNF has been linked to the pathology of the most common neurodegenerative disorders, such as Alzheimer’s and Parkinson’s disease. This review aims to describe recent efforts to understand the connection between the level of BDNF and neurodegenerative diseases. Several studies have shown that a high level of BDNF is associated with a lower risk for developing a neurodegenerative disease.

Expression of BDNF-Associated lncRNAs in Parkinson's disease

Decreased level of neurotrophic factor brain-derived neurotrophic factor (BDNF) has been supposed to participate in the pathoetiology of Parkinson's disease (PD). However, the underlying mechanisms of its dysregulation and the functional network between this factor and other transcripts have not been elucidated. In the current study, we measured expressions of BDNF, and four related long non-coding RNAs, namely BDNF-AS, MIR137HG, MIAT and PNKY in blood of PD patients and normal controls to find their expression levels in these patients and propose a possible mechanism for dysregulation of BDNF in PD patients. Notably, we detected down-regulation of all transcripts in the circulation of PD patients compared with controls. There was no significant difference in expression of either gene between male and female PD patients or patients receiving L-Dopa versus those receiving other drugs. Expression of none of genes was correlated with age, disease duration, disease stage, MMSE or UPDRS. Dynamic principal component analysis showed that expression levels of these genes almost clearly separated samples collected from healthy controls and PD patients into their respective groups. This suggests that the observed lncRNAs differences are associated with the pathophysiology of PD, and these lncRNAs might constitute an important biomarker signature for PD.

Biosensor approaches on the diagnosis of neurodegenerative diseases: Sensing the past to the future

Early diagnosis of neurodegeneration-oriented diseases that develop with the aging world is essential for improving the patient's living conditions as well as the treatment of the disease. Alzheimer's and Parkinson's diseases are prominent examples of neurodegeneration characterized by dementia leading to the death of nerve cells. The clinical diagnosis of these diseases only after the symptoms appear, delays the treatment process. Detection of biomarkers, which are distinctive molecules in biological fluids, involved in neurodegeneration processes, has the potential to allow early diagnosis of neurodegenerative diseases. Studies on biosensors, whose main responsibility is to detect the target analyte with high specificity, has gained momentum in recent years with the aim of high detection of potential biomarkers of neurodegeneration process. This study aims to provide an overview of neuro-biosensors developed on the basis of biomarkers identified in biological fluids for the diagnosis of neurodegenerative diseases such as Alzheimer's disease (AD), and Parkinson's disease (PD), and to provide an overview of the urgent needs in this field, emphasizing the importance of early diagnosis in the general lines of the neurodegeneration pathway. In this review, biosensor systems developed for the detection of biomarkers of neurodegenerative diseases, especially in the last 5 years, are discussed.

Association of Decreased Serum BDNF With Restless Legs Syndrome in Parkinson's Disease Patients

Objective: To objective of the study was to investigate whether serum brain-derived neurotrophic factor (BDNF) levels are associated with the severity of restless legs syndrome (RLS) in Parkinson's disease (PD). Methods: A total of 249 PD patients with (n = 53) and without RLS (n = 196) and 326 age-matched controls were included in this study. All the serum BDNF levels of the participants were measured. The International Restless Legs Syndrome Study Group Rating Scale (IRLSSG-RS) was administered for the severity of RLS. The severity of PD patients were assessed by the Unified PD Rating Scale (UPDRS) and the Hoehn and Yahr (H-Y) stage. Results: The prevalence of RLS was significantly higher in PD patients (21.3%) than in the controls group (7.4%) (p < 0.05). The IRLSSG-RS score in PD patients with RLS (16.25 ± 5.24) was significantly increased than in controls with RLS (12.08 ± 3.99) (p < 0.01). The serum BDNF levels were significantly decreased in PD patients with RLS than in PD patients without RLS, controls without RLS, and controls with RLS (p < 0.001). BDNF levels were negatively associated with IRLSSG-RS in both PD patients with RLS and controls with RLS group (both p < 0.01). Multiple regression analysis confirmed that in either PD with RLS or controls with RLS group, BDNF was an independent contributor to IRLSSG-RS (both p < 0.01). Conclusions: Decreased serum BDNF levels may be involved in the pathophysiology of RLS in PD, suggesting that it may serve as a potential blood biomarker of diagnostic value for RLS in PD.

Serum mBDNF and ProBDNF Expression Levels as Diagnosis Clue for Early Stage Parkinson's Disease

Parkinson's disease (PD) is one of the most common chronic, progressive, and neurodegenerative diseases characterized clinically by resting tremor, bradykinesia, rigidity, and postural instability. As this disease is usually detected in the later stages, the cure is often delayed, ultimately leading to disability due to the lack of early diagnostic techniques. Therefore, it is of great importance to identify reliable biomarkers with high sensitivity and specificity for the early diagnosis of PD. In this study, we aimed to investigate whether serum expressions of mature brain-derived neurotrophic factor (mBDNF) and proBDNF can serve as biomarkers for the diagnosis of PD at early stage. One hundred and fifty-six patients with limb tremor and/or bradykinesia meeting the inclusion criteria were assigned to either ex-PD group (PD cases) or ex-NPD group (non-PD cases) and then reassigned to either po-PD group (with PD) or po-NPD group (without PD) at 1-year follow-up based on the results of the rediagnoses as performed in accordance with MDS Parkinson's diagnostic criteria. To improve early diagnostic accuracy, grouping (PD group and non-PD group) at initial visit and follow-up was performed differently and independently. Serum mBDNF and proBDNF levels were measured by enzyme-linked immunosorbent assays. The results demonstrated that serum levels of mBDNF and mBDNF/proBDNF were significantly lower in the ex-PD group (19.73 ± 7.31 and 0.09 ± 0.05 ng/ml) as compared with the ex-NPD group (23.47 ± 8.21 and 0.15 ± 0.12 ng/ml) (p < 0.01 for both) and in the po-PD group (19.24 ± 7.20 and 0.09 ± 0.05 ng/ml) as compared with the po-NPD group (25.05 ± 7.67 and 0.16 ± 0.14 ng/ml) (p < 0.01 for both). However, a significantly higher serum level of proBDNF was noted in the ex-PD group (235.49 ± 60.75 ng/ml) as compared with the ex-NPD group (191.75 ± 66.12 ng/ml) (p < 0.01) and in the po-PD group (235.56 ± 60.80 ng/ml) as compared with the po-NPD group (188.42 ± 65.08 ng/ml) (p < 0.01). In conclusion, mBDNF/proBDNF can be used as biomarkers for early stage Parkinson's disease; in addition, mBDNF plus proBDNF has better diagnostic value than mBDNF alone in the diagnosis of PD.

Further Characterization of Intrastriatal Lipopolysaccharide Model of Parkinson's Disease in C57BL/6 Mice

Parkinson's disease (PD) is the most common movement disorder, characterized by progressive degeneration of the nigrostriatal pathway, which consists of dopaminergic cell bodies in substantia nigra and their neuronal projections to the striatum. Moreover, PD is associated with an array of non-motor symptoms such as olfactory dysfunction, gastrointestinal dysfunction, impaired regulation of the sleep-wake cycle, anxiety, depression, and cognitive impairment. Inflammation and concomitant oxidative stress are crucial in the pathogenesis of PD. Thus, this study aimed to model PD via intrastriatal injection of the inflammagen lipopolysaccharide (LPS)to investigate if the lesion causes olfactory and motor impairments, inflammation, oxidative stress, and alteration in synaptic proteins in the olfactory bulb, striatum, and colon. Ten µg of LPS was injected unilaterally into the striatum of 27 male C57BL/6 mice, and behavioural assessment was conducted at 4 and 8 weeks post-treatment, followed by tissue collection. Intrastriatal LPS induced motor impairment in C57BL/6 mice at 8 weeks post-treatment evidenced by reduced latency time in the rotarod test. LPS also induced inflammation in the striatum characterized by increased expression of microglial marker Iba-1 and astrocytic marker GFAP, with degeneration of dopaminergic neuronal fibres (reduced tyrosine hydroxylase immunoreactivity), and reduction of synaptic proteins and DJ-1 protein. Additionally, intrastriatal LPS induced inflammation, oxidative stress and alterations in synaptic proteins within the olfactory bulb, although this did not induce a significant impairment in olfactory function. Intrastriatal LPS induced mild inflammatory changes in the distal colon, accompanied by increased protein expression of 3-nitrotyrosine-modified proteins. This model recapitulated the major features of PD such as motor impairment and degeneration of dopaminergic neuronal fibres in the striatum, as well as some pathological changes in the olfactory bulb and colon; thus, this model could be suitable for understanding clinical PD and testing neuroprotective strategies.

The efficacy of systemic administration of lipopolysaccharide in modelling pre-motor Parkinson's disease in C57BL/6 mice

Parkinson's disease (PD) is the second most common neurodegenerative disease, characterised by the loss of dopaminergic neurons in the substantia nigra. Mounting evidence indicates a crucial role of inflammation and concomitant oxidative stress in the disease progression. Therefore, the aim of this study was to investigate the ability of systemically administered lipopolysaccharide (LPS) to induce motor and non-motor symptoms of PD, inflammation, oxidative stress and major neuropathological hallmarks of the disease in regions postulated to be affected, including the olfactory bulb, hippocampus, midbrain and cerebellum. Twenty-one male C57BL/6 mice, approximately 20 weeks old, received a dose of 0.3 mg/kg/day of LPS systemically on 4 consecutive days and behavioural testing was conducted on days 14-18 post-treatment, followed by tissue collection. Systemically administered LPS increased latency time in the buried food seeking test (indicative of olfactory impairment), and decreased time spent in central zone of the open field (anxiety-like behaviour). However, there was no change in latency time in the rotarod test or the expression of tyrosine hydroxylase (TH) in the midbrain. Systemically administered LPS induced increased glial markers GFAP and Iba-1 and oxidative stress marker 3-nitrotyrosine (3-NT) in the olfactory bulb, hippocampus, midbrain and cerebellum, and there were region specific changes in the expression of NFκB, IL-1β, α-synuclein, TH and BDNF proteins. The model could be useful to further elucidate early non-motor aspects of PD and the possible mechanisms contributing to the non-motor deficits.

A Single Session of Whole-Body Electromyostimulation Increases Muscle Strength, Endurance and proNGF in Early Parkinson Patients

Parkinson's disease (PD) patients lead a sedentary lifestyle, being unable or unwilling to exercise conventionally, due to physical and mental limitations. The aim of this study was to assess the acute effects of a single session of whole-body electromyostimulation (WB-EMS) on the physical performances and serum levels of the neurotrophic factors in PD patients. Ten subjects (aged 72.60 ± 6.82) underwent 20 min of physical activity with superimposed WB-EMS and, after four weeks, the same protocol with no WB-EMS. WB-EMS was conducted with intermittent stimulation, with 4 s WB-EMS/4 s rest, at 85 Hz, 350 μs. A physical fitness assessment and blood samples collection, to evaluate neurotrophic factors' levels (BDNF, FGF21, proNGF, mNGF), were collected before and after the intervention. The RM-ANOVA showed significant improvements in sit-to-stand (p < 0.01), arm curl (p < 0.01), handgrip (p < 0.01) and soda pop test (p < 0.01) after the WB-EMS intervention. Higher proNFG serum levels were observed in the WB-EMS condition compared to the no WB-EMS after 60 min post-intervention (p = 0.0163). The effect of WB-EMS confirmed the electrostimulation ability to modulate the proNGF quantity. The positive impact of the WB-EMS protocol on physical functioning, and eye-hand coordination, makes this intervention a promising strategy to improve motor and non-motor symptoms in PD patients.

ERRγ ligand HPB2 upregulates BDNF-TrkB and enhances dopaminergic neuronal phenotype

Brain derived neurotrophic factor (BDNF) promotes maturation of dopaminergic (DAergic) neurons in the midbrain and positively regulates their maintenance and outgrowth. Therefore, understanding the mechanisms regulating the BDNF signaling pathway in DAergic neurons may help discover potential therapeutic strategies for neuropsychological disorders associated with dysregulation of DAergic neurotransmission. Because estrogen-related receptor gamma (ERRγ) is highly expressed in both the fetal nervous system and adult brains during DAergic neuronal differentiation, and it is involved in regulating the DAergic neuronal phenotype, we asked in this study whether ERRγ ligand regulates BDNF signaling and subsequent DAergic neuronal phenotype. Based on the X-ray crystal structures of the ligand binding domain of ERRγ, we designed and synthesized the ERRγ agonist, (E)-4-hydroxy-N'-(4-(phenylethynyl)benzylidene)benzohydrazide (HPB2) (K_d value, 8.35 μmol/L). HPB2 increased BDNF mRNA and protein levels, and enhanced the expression of the BDNF receptor tropomyosin receptor kinase B (TrkB) in human neuroblastoma SH-SY5Y, differentiated Lund human mesencephalic (LUHMES) cells, and primary ventral mesencephalic (VM) neurons. HPB2-induced upregulation of BDNF was attenuated by GSK5182, an antagonist of ERRγ, and siRNA-mediated ERRγ silencing. HPB2-induced activation of extracellular-signal-regulated kinase (ERK) and phosphorylation of cAMP-response element binding protein (CREB) was responsible for BDNF upregulation in SH-SY5Y cells. HPB2 enhanced the DAergic neuronal phenotype, namely upregulation of tyrosine hydroxylase (TH) and DA transporter (DAT) with neurite outgrowth, both in SH-SY5Y and primary VM neurons, which was interfered by the inhibition of BDNF-TrkB signaling, ERRγ knockdown, or blockade of ERK activation. HPB2 also upregulated BDNF and TH in the striatum and induced neurite elongation in the substantia nigra of mice brain. In conclusion, ERRγ activation regulated BDNF expression and the subsequent DAergic neuronal phenotype in neuronal cells. Our results might provide new insights into the mechanism underlying the regulation of BDNF expression, leading to novel therapeutic strategies for neuropsychological disorders associated with DAergic dysregulation.

Serum BDNF discriminates Parkinson's disease patients with depression from without depression and reflect motor severity and gender differences

OBJECTIVE

To evaluate the diagnostic value of serum Brain-derived neurotrophic factor (BDNF) levels for discriminating PD with depression from without depression, and to investigate whether serum BDNF levels were associated with motor severity and gender in depressed PD patients.

METHODS

Demographic and clinical data were collected from 122 PD patients with depression, 137 without depression and 110 healthy controls. All participants' serum BDNF concentrations were measured. Their motor abilities and activity were assessed by the Unified PD Rating Scale Part III (UPDRS III) score and the Hoehn and Yahr (H-Y) stage. Depression was scored using the 17-item Hamilton Rating Scale for Depression (HAMD-17). Associations were analyzed with multivariate regression.

RESULTS

The serum BDNF levels were lower in depressed PD patients compared to non-depressed PD patients and controls (p < 0.001). The BDNF levels were negatively correlated with UPDRS III score (r = - 0.54, p < 0.001) and H-Y stage (r = - 0.45, p < 0.001). Decreased BDNF levels were associated with women only among depressed PD patients (r = 0.45, p < 0.001). The HAMD-17 score was negatively correlated with BDNF levels (r = - 0.59, p < 0.001), and positively associated with UPDRS III score (r = 0.51, p < 0.001). Multiple regression analysis demonstrated that in the depressed PD patients, female, H-Y stage and UPDRS III score were independent contributors to the BDNF levels (p < 0.001; p = 0.006; p = 0.03, respectively), BDNF and UPDRS III score were independent contributors to HAMD-17 score (p < 0.001, p = 0.01, respectively).

CONCLUSIONS

Decreased serum BDNF levels may be a useful clinical biomarker of depression in PD patients. Serum BDNF may serve as a potential biomarker for motor severity of PD patients with depression, especially in female.

Mild traumatic brain injury exacerbates Parkinson's disease induced hemeoxygenase-2 expression and brain pathology: Neuroprotective effects of co-administration of TiO2 nanowired mesenchymal stem cells and cerebrolysin

Mild traumatic brain injury (mTBI) is one of the leading predisposing factors in the development of Parkinson's disease (PD). Mild or moderate TBI induces rapid production of tau protein and alpha synuclein (ASNC) in the cerebrospinal fluid (CSF) and in several brain areas. Enhanced tau-phosphorylation and ASNC alters the molecular machinery of the brain leading to PD pathology. Recent evidences show upregulation of constitutive isoform of hemeoxygenase (HO-2) in PD patients that correlates well with the brain pathology. mTBI alone induces profound upregulation of HO-2 immunoreactivity. Thus, it would be interesting to explore whether mTBI exacerbates PD pathology in relation to tau, ASNC and HO-2 expression. In addition, whether neurotrophic factors and stem cells known to reduce brain pathology in TBI could induce neuroprotection in PD following mTBI. In this review role of mesenchymal stem cells (MSCs) and cerebrolysin (CBL), a well-balanced composition of several neurotrophic factors and active peptide fragments using nanowired delivery in PD following mTBI is discussed based on our own investigation. Our results show that mTBI induces concussion exacerbates PD pathology and nanowired delivery of MSCs and CBL induces superior neuroprotection. This could be due to reduction in tau, ASNC and HO-2 expression in PD following mTBI, not reported earlier. The functional significance of our findings in relation to clinical strategies is discussed.

Fruit Quality Characterization of New Sweet Cherry Cultivars as a Good Source of Bioactive Phenolic Compounds with Antioxidant and Neuroprotective Potential

Sweet cherries (Prunus avium L.) are highly appreciated fruits for their taste, color, nutritional value, and beneficial health effects. In this work, seven new cultivars of sweet cherry were investigated for their main quality traits and nutraceutical value. The phytochemical profile of three classes of phenolic compounds and the antioxidant activity of the new cultivars were investigated through high-performance liquid chromatography with diode array detection (HPLC-DAD) and spectrophotometric assays, respectively, and compared with those of commonly commercialized cultivars. Cyanidine-3-O-rutinoside was the main anthocyanin in all genotypes, and its levels in some new cultivars were about three-fold higher than in commercial ones. The ORAC-assayed antioxidant capacity was positively correlated with the total anthocyanin index. The nutraceutical value of the new cultivars was investigated in terms of antioxidant/neuroprotective capacity in neuron-like SH-SY5Y cells. Results demonstrated that the new cultivars were more effective in counteracting oxidative stress and were also able to upregulate brain-derived neurotrophic factor (BDNF), a pro-survival neurotrophin, suggesting their potential pleiotropic role in counteracting neurodegenerations.

Neurotrophic factors for disease-modifying treatments of Parkinson's disease: gaps between basic science and clinical studies

Abstract

Background

Neurotrophic factors are endogenous proteins promoting the survival of different neural cells. Therefore, they elicited great interest as a possible treatment for neurodegenerative disorders, including Parkinson’s Disease (PD). PD is the second most common neurodegenerative disorder, scientifically characterized more than 200 years ago and initially linked with motor abnormalities. Currently, the disease is viewed as a highly heterogeneous, progressive disorder with a long presymptomatic phase, and both motor and non-motor symptoms. Presently only symptomatic treatments for PD are available. Neurohistopathological changes of PD affected brains have been described more than 100 years ago and characterized by the presence of proteinaceous inclusions known as Lewy bodies and degeneration of dopamine neurons. Despite more than a century of investigations, it has remained unclear why dopamine neurons die in PD.

Methods

This review summarizes literature data from preclinical studies and clinical trials of neurotrophic factor based therapies for PD and discuss it from the perspective of the current understanding of PD biology.

Results

Newest data point towards dysfunctions of mitochondria, autophagy-lysosomal pathway, unfolded protein response and prion protein-like spreading of misfolded alpha-synuclein that is the major component of Lewy bodies. Yet, the exact chain of events leading to the demise of dopamine neurons is unclear and perhaps different in subpopulations of patients.

Conclusions

Gaps in our understanding of underlying disease etiology have hindered our attempts to find treatments able to slow down the progression of PD.

Graphic abstract

BDNF as a Promising Therapeutic Agent in Parkinson's Disease

Brain-derived neurotrophic factor (BDNF) promotes neuroprotection and neuroregeneration. In animal models of Parkinson’s disease (PD), BDNF enhances the survival of dopaminergic neurons, improves dopaminergic neurotransmission and motor performance. Pharmacological therapies of PD are symptom-targeting, and their effectiveness decreases with the progression of the disease; therefore, new therapeutical approaches are needed. Since, in both PD patients and animal PD models, decreased level of BDNF was found in the nigrostriatal pathway, it has been hypothesized that BDNF may serve as a therapeutic agent. Direct delivery of exogenous BDNF into the patient’s brain did not relieve the symptoms of disease, nor did attempts to enhance BDNF expression with gene therapy. Physical training was neuroprotective in animal models of PD. This effect is mediated, at least partly, by BDNF. Animal studies revealed that physical activity increases BDNF and tropomyosin receptor kinase B (TrkB) expression, leading to inhibition of neurodegeneration through induction of transcription factors and expression of genes related to neuronal proliferation, survival, and inflammatory response. This review focuses on the evidence that increasing BDNF level due to gene modulation or physical exercise has a neuroprotective effect and could be considered as adjunctive therapy in PD.

Anti-neuroinflammatory, protective effects of the synthetic microneurotrophin BNN-20 in the advanced dopaminergic neurodegeneration of "weaver" mice

BNN-20 is a synthetic microneurotrophin, long-term (P1-P21) administration of which exerts potent neuroprotective effect on the "weaver" mouse, a genetic model of progressive, nigrostriatal dopaminergic degeneration. The present study complements and expands our previous work, providing evidence that BNN-20 fully protects the dopaminergic neurons even when administration begins at a late stage of dopaminergic degeneration (>40%). Since neuroinflammation plays a critical role in Parkinson's disease, we investigated the possible anti-neuroinflammatory mechanisms underlying the pharmacological action of BNN-20. The latter was shown to be microglia-mediated, at least in part. Indeed, BNN-20 induced a partial, but significant, reversal of microglia hyperactivation, observed in the untreated "weaver" mouse. Furthermore, it induced a shift in microglia polarization towards the neuroprotective M2 phenotype, suggesting a possible beneficial shifting of microglia activity. This observation was further supported by morphometric measurements. Moreover, BDNF levels, which were severely reduced in the "weaver" mouse midbrain, were restored to normal even after short-term BNN-20 administration. Experiments in "weaver"/NGL (dual GFP/luciferase-NF-κВ reporter) mice using bioluminescence after a short BNN-20 treatment (P60-P74), have shown that the increase of BDNF production was specifically mediated through the TrkB-PI3K-Akt-NF-κB signaling pathway. Interestingly, long-term BNN-20 treatment (P14-P60) significantly increased dopamine levels in the "weaver" striatum, which seems to be associated with the improved motor activity observed in the treated mutant animals. In conclusion, our findings suggest that BNN-20 may serve as a lead molecule for new therapeutic compounds for Parkinson's disease, combining strong anti-neuroinflammatory and neuroprotective properties, leading to elevated dopamine levels and improved motor activity.

Parkinson's Disease-Associated Changes in the Expression of Neurotrophic Factors and their Receptors upon Neuronal Differentiation of Human Induced Pluripotent Stem Cells

Parkinson's disease (PD) is a neurodegenerative pathology resulting from the degeneration of dopaminergic (DA) neurons in the substantia nigra (SN). Neurotrophic factors (NTFs) and their receptors are key regulators of the survival, differentiation, and development of neurons. However, the role of these factors in the pathogenesis of PD is still unclear. Here, we analyzed the expression of NTFs and their receptors in human induced pluripotent stem cells (iPSCs) derived from the fibroblasts of patients with PD and healthy donors (HDs). Four PD-derived iPSC lines with different mutations and three cell lines from HDs at different stages of neuronal differentiation were used for RT-qPCR analysis and ELISA. We found that the mRNA levels of most analyzed genes were altered in PD-derived cells compared with those in HD-derived cells at all stages. Importantly, irrespective of PD-associated mutations, the mRNA levels of the BDNF and GDNF genes were mostly increased or unchanged in predominantly DA terminally differentiated neurons (TDNs) compared with those in HD-derived cells. Strikingly, in contrast to BDNF and GDNF mRNA levels, BDNF and GDNF protein levels were lower in almost all PD-derived TDNs than in HD-derived cells, thus indicating the dysregulation of NTF expression at the post-transcriptional level. We suggest that this dysregulation is one of the important signs of PD development.

Neuroregeneration in Parkinson's Disease: From Proteins to Small Molecules

Background:

Parkinson’s disease (PD) is the second most common neurodegenerative disorder worldwide, the lifetime risk of developing this disease is 1.5%. Motor diagnostic symptoms of PD are caused by degeneration of nigrostria-tal dopamine neurons. There is no cure for PD and current therapy is limited to supportive care that partially alleviates dis-ease signs and symptoms. As diagnostic symptoms of PD result from progressive degeneration of dopamine neurons, drugs restoring these neurons may significantly improve treatment of PD.

Method:

A literature search was performed using the PubMed, Web of Science and Scopus databases to discuss the pro-gress achieved in the development of neuroregenerative agents for PD. Papers published before early 2018 were taken into account.

Results:

Here, we review several groups of potential agents capable of protecting and restoring dopamine neurons in cul-tures or animal models of PD including neurotrophic factors and small molecular weight compounds.

Conclusion:

Despite the promising results of in vitro and in vivo experiments, none of the found agents have yet shown conclusive neurorestorative properties in PD patients. Meanwhile, a few promising biologicals and small molecules have been identified. Their further clinical development can eventually give rise to disease-modifying drugs for PD. Thus, inten-sive research in the field is justified.