Gene therapy for aromatic L-amino acid decarboxylase deficiency by MR-guided direct delivery of AAV2-AADC to midbrain dopaminergic neurons.

Aromatic L-amino acid decarboxylase (AADC) deficiency is a rare genetic disorder characterized by deficient synthesis of dopamine and serotonin. It presents in early infancy, and causes severe developmental disability and lifelong motor, behavioral, and autonomic symptoms including oculogyric crises (OGC), sleep disorder, and mood disturbance. We investigated the safety and efficacy of delivery of a viral vector expressing AADC (AAV2-hAADC) to the midbrain in children with AADC deficiency (ClinicalTrials.gov Identifier NCT02852213). Seven (7) children, aged 4-9 years underwent convection-enhanced delivery (CED) of AAV2-hAADC to the bilateral substantia nigra (SN) and ventral tegmental area (VTA) (total infusion volume: 80 µL per hemisphere) in 2 dose cohorts: 1.3 × 1011 vg (n = 3), and 4.2 × 1011 vg (n = 4). Primary aims were to demonstrate the safety of the procedure and document biomarker evidence of restoration of brain AADC activity. Secondary aims were to assess clinical improvement in symptoms and motor function. Direct bilateral infusion of AAV2-hAADC was safe, well-tolerated and achieved target coverage of 98% and 70% of the SN and VTA, respectively. Dopamine metabolism was increased in all subjects and FDOPA uptake was enhanced within the midbrain and the striatum. OGC resolved completely in 6 of 7 subjects by Month 3 post-surgery. Twelve (12) months after surgery, 6/7 subjects gained normal head control and 4/7 could sit independently. At 18 months, 2 subjects could walk with 2-hand support. Both the primary and secondary endpoints of the study were met. Midbrain gene delivery in children with AADC deficiency is feasible and safe, and leads to clinical improvements in symptoms and motor function.

Restless legs syndrome in Parkinson disease: Clinical characteristics, abnormal iron metabolism and altered neurotransmitters.

Relationships among clinical characteristics, iron metabolism and neurotransmitters in Parkinson disease (PD) patients with restless legs syndrome (RLS) remains unclear. We divided 218 patients into PD with and with no RLS (PD-RLS and PD-NRLS) groups by RLS-rating scale (RLS-RS) score. Motor and non-motor symptoms were rated by related scales. Iron and related proteins, and neurotransmitters in cerebrospinal fluid (CSF) and serum were measured. PD-RLS frequency was 40.37%. PD-RLS group had longer duration, higher stage and scores of motor symptoms, depression, anxiety, sleep disorders, fatigue and apathy, and increased transferrin and decreased iron, ferritin, dopamine (DA) and 5-hydroxytryptamine (5-HT) in CSF. In CSF of PD-RLS group, RLS-RS score was positively correlated with transferrin level and negatively correlated with iron and ferritin levels; RLS-RS score was negatively correlated with DA and 5-HT levels; transferrin level was negatively correlated with DA and 5-HT levels, and ferritin level was positively correlated with DA level. In serum, PD-RLS group had decreased iron and transferrin levels, which were negatively correlated with RLS-RS score. PD-RLS was common and severer in motor and some non-motor symptoms. Iron deficiency induced by its metabolism dysfunctions in peripheral and central systems might cause PD-RLS through decreasing brain DA and 5-HT.

Presente y futuro de la estimulación magnética transcraneal / Present and future of the transcranial magnetic stimulation

La estimulación magnética transcraneal ha llamado la atención de neurocientíficos y público en general por la posibilidad de estimular y “controlar” el sistema nervioso de forma no invasiva, realizar diagnósticos más exactos, y aplicar tratamientos y programas de rehabilitación más efectivos en múltiples enfermedades que afectan el sistema nervioso. Así mismo, esta novedosa herramienta ha ayudado a develar la complejidad del comportamiento neural, sus conexiones y su modulación plástica. La estimulación magnética aplicada de manera simple o pareada, se ha convertido en una alternativa útil en el diagnóstico de enfermedades como esclerosis múltiple, enfermedad de Parkinson, epilepsia, distonía, esclerosis lateral amiotrófica, enfermedad cerebro vascular, así como el sueño y sus trastornos, entre otras alteraciones. A nivel terapéutico, se ha sugerido el uso de la estimulación magnética repetitiva con diferentes niveles de evidencia en depresión refractaria a tratamiento farmacológico convencional, tinitus, afonía psicógena, enfermedad de Alzheimer, autismo, enfermedad de Parkinson, distonías, accidente cerebro vascular, epilepsia, trastornos de ansiedad generalizada, estrés post-traumático, alucinaciones auditivas, dolor crónico, afasias, trastorno obsesivo compulsivo, disquinesias inducidas por L-Dopa, manía y síndrome de Rasmussen, entre otros trastornos. Su beneficio en neurorehabilitación es una realidad inocultable, en cuyo caso se ha podido usar con efectividad y, prácticamente, sin efectos secundarios.

Magnetic stimulation has called the attention of neuroscientists and the public due to the possibility to stimulate and “control” the nervous system in a non-invasive way. It has helped to make more accurate diagnosis, and apply more effective treatments and rehabilitation protocols in several diseases that affect the nervous system. Likewise, this novel tool has increased our knowledge about complex neural behavior, its connections as well as its plastic modulation. Magnetic stimulation applied in simple or paired-pulse protocols is a useful alternative in the diagnosis of diseases such as multiple sclerosis, Parkinson disease, epilepsy, dystonia, amyotrophic lateral sclerosis, cerebrovascular disease, and sleep disorders. From the therapeutic perspective, magnetic stimulation applied repetitively has been found useful, with different degrees of efficacy, in treating resistant depression, tinnitus, psychogenic dysphonia, Alzheimer disease, autism, Parkinson disease, dystonia, stroke, epilepsy, generalized anxiety as well as post traumatic stress disorder, auditory hallucinations, chronic pain, aphasias, obsessive-compulsive disorders, L-dopa induced dyskynesia, mania and Rasmussen syndrome, among others. The potential of magnetic stimulation in neurorehabilitation is outstanding, with excellent range of safety and, in practical terms, without side effects.

Gene therapy for aromatic L-amino acid decarboxylase deficiency.

Aromatic L-amino acid decarboxylase (AADC) is required for the synthesis of the neurotransmitters dopamine and serotonin. Children with defects in the AADC gene show compromised development, particularly in motor function. Drug therapy has only marginal effects on some of the symptoms and does not change early childhood mortality. Here, we performed adeno-associated viral vector-mediated gene transfer of the human AADC gene bilaterally into the putamen of four patients 4 to 6 years of age. All of the patients showed improvements in motor performance: One patient was able to stand 16 months after gene transfer, and the other three patients achieved supported sitting 6 to 15 months after gene transfer. Choreic dyskinesia was observed in all patients, but this resolved after several months. Positron emission tomography revealed increased uptake by the putamen of 6-[(18)F]fluorodopa, a tracer for AADC. Cerebrospinal fluid analysis showed increased dopamine and serotonin levels after gene transfer. Thus, gene therapy targeting primary AADC deficiency is well tolerated and leads to improved motor function.

Clinical utility of monoamine neurotransmitter metabolite analysis in cerebrospinal fluid.

BACKGROUND: Measurements of monoamine neurotransmitters and their metabolites in plasma and urine are commonly used to aid in the detection and monitoring of neuroblastoma and pheochromocytoma and the evaluation of hypotension or hypertension. Measurements of these neurotransmitters and metabolites can also be helpful in the investigation of disorders that primarily affect the central nervous system, but only when the measurements are made in cerebrospinal fluid (CSF). CONTENT: I describe CSF profiles of monoamine metabolites in the primary and secondary defects affecting serotonin and catecholamine metabolism. I outline the methods required to analyze these metabolites together with details of specific sample handling requirements, sample stability, and interfering compounds, and I emphasize a need for age-related reference intervals. SUMMARY: Measured values of monoamine metabolites in CSF provide only a single-time snapshot of the overall turnover of the monoamine neurotransmitters within the brain. Because these measurements reflect the average concentrations accumulated from all brain regions plus the regional changes that occur within the spinal cord, they may miss subtle abnormalities in particular brain regions or changes that occur on a minute-to-minute or diurnal basis. Clearly defined diagnosed disorders are currently limited to those affecting synthetic and catabolic pathways. In many cases, abnormal monoamine metabolite concentrations are found in CSF and an underlying etiology cannot be found. Molecular screening of candidate genes related to steps in the neurotransmission process, including storage in presynaptic nerve vesicles, release, interaction with receptors, and reuptake, might be a fruitful endeavor in these cases.

The mechanism and effect of chronic electrical stimulation of the globus pallidus for treatment of Parkinson disease.

OBJECT: Although chronic electrical stimulation of the globus pallidus (GP) has been shown to ameliorate motor disabilities in Parkinson disease (PD), the underlying mechanism remains to be clarified. In this study the authors explored the mechanism for the effects of deep brain stimulation of the GP by investigating the changes in neurotransmitter levels in the cerebrospinal fluid (CSF) during the stimulation. METHODS: Thirty patients received chronic electrical stimulation of the GP internus (GPi). Clinical effects were assessed using the Unified PD Rating Scale (UPDRS) and the Hoehn and Yahr Staging Scale at 1 week before surgery and at 6 and 12 months after surgery. One day after surgery, CSF samples were collected through a ventricular tube before and 1 hour after GPi stimulation. The concentration of neurotransmitters such as gamma-aminobutyric acid (GABA), noradrenaline, dopamine, and homovanillic acid (HVA) in the CSF was measured using high-performance liquid chromatography. The treatment was effective for tremors, rigidity, and drug-induced dyskinesia. The concentration of GABA in the CSF increased significantly during stimulation, although there were no significant changes in the level of noradrenaline, dopamine, and HVA. A comparison between an increased rate of GABA concentration and a lower UPDRS score 6 months postimplantation revealed that the increase in the GABA level correlated with the stimulation-induced clinical effects. CONCLUSIONS: Stimulation of the GPi substantially benefits patients with PD. The underlying mechanism of the treatment may involve activation of GABAergic afferents in the GP.

[Cerebral microdialysis in stroke]. / Zerebrale Mikrodialyse beim Schlaganfall.

Cerebral microdialysis is an invasive technique for neurochemical monitoring that has been established for neuro-critical disorders such as subarachnoid hemorrhage and severe brain injury. We present data on cerebral microdialysis in stroke patients which were obtained in an ongoing study supported by the German Ministry for Education and Research. So far, 50 patients have been included who required critical care due to massive stroke of the middle cerebral artery territory. By correlating the microdialysis results with follow-up CT scans, we could define the neurochemical characteristics of three different brain compartments: (1) noninfarcted brain tissue with normal microdialysis values, (2) brain areas adjacent to the infarct core which were not hypodense in CT scans but caused reversible neurochemical alterations, and (3) the infarct core with massive concentration changes which did not normalize over the measuring period of 3 to 5 days. Microdialysis values averaged over time and correlated with initial PET scans helped to describe neurochemical predictors of a malignant, i.e., life-threatening, space-occupying course of the ischemic stroke. We discuss the value of this method in guiding therapy and predicting clinical outcome in the context of other neurological critical care disorders and describe the pros and cons of cerebral microdialysis as an invasive monitoring technique.

Monoaminergic effects of high-dose corticotropin in corticotropin-responsive pediatric opsoclonus-myoclonus.

Children with the opsoclonus-myoclonus syndrome (OMS) usually respond to corticotropin (adrenocorticotrophic hormone, ACTH) treatment but the mechanism of benefit is unknown. We previously showed that both cerebrospinal fluid (CSF) homovanillic acid (HVA) and 5-hydroxyindole-acetic acid (5-HIAA) concentrations are low in pediatric OMS. In this study, we measured levels of CSF Dopa, catecholamines, deaminated metabolites of catecholamines, as well as HVA and 5-HIAA in eight patients before and during treatment with ACTH. All the children were ACTH-responsive with 50-70% improvement in multiple clinical features of OMS. ACTH treatment reduced the HVA concentration in every child by a mean of 21% (p < 0.001). Treatment with ACTH was associated with significant correlations between dopaminergic markers such as HVA, dihydroxyphenylacetic acid (DOPAC), and Dopa. There were no significant changes in the CSF concentrations of the noradrenergic markers norepinephrine (NE) and dihydroxyphenylglycol (DHPG), or the serotonergic marker 5-HIAA. The only child with a marked inflammatory pattern in CSF, which was reversed by ACTH, was atypical for a large increase in NE and decrease in 5-HIAA during ACTH treatment. Beneficial effects of ACTH in OMS are not associated with normalization of HVA or 5-HIAA levels. The pattern of decreased HVA and unchanged DOPAC levels could reflect decreased extraneuronal uptake of catecholamines (which steroids inhibit) or decreased 0-methylation of catecholamines in nonneuronal cells.

Cerebrospinal fluid levels of biopterin, nitric oxide metabolites, and immune activation markers and the clinical course of human cerebral malaria.

Cerebrospinal fluid samples from 130 children who presented with cerebral malaria were investigated to elucidate the impact of biopterin production, NO formation, and local immune activation on the clinical course of this disease. Biopterin levels were significantly lower in patients who were in a deeper coma (P = .02). Cerebrospinal fluid concentrations of NO were significantly higher in children who died than in survivors (P = .037); however, this was not the case for macrophage activation markers, neopterin, and soluble tumor necrosis factor receptor p75 (sTNFR-75). Biopterin, neopterin, and sTNFR-75 but not NO concentrations were significantly related to each other. Low biopterin levels in deep coma are compatible with an impaired local Th1 response, but the low levels could also be due to the scavenging of radicals or to decreased neurotransmitter synthesis. Local production of NO, most likely by nonimmune mechanisms, may be detrimental in cerebral malaria; however, this appears not to be the case for local Th1-mediated immune pathways.

Acetyl-L-carnitine in Alzheimer disease: a short-term study on CSF neurotransmitters and neuropeptides.

Acetyl-L-carnitine (ALCAR) is a drug currently under investigation for Alzheimer disease (AD) therapy. ALCAR seems to exert a number of central nervous system (CNS)-related effects, even though a clear pharmacological action that could explain clinical results in AD has not been identified yet. The aim of this study was to determine cerebrospinal fluid (CSF) and plasma biological correlates of ALCAR effects in AD after a short-term, high-dose, intravenous, open treatment. Results show that ALCAR CSF levels achieved under treatment were significantly higher than the ones at baseline, reflecting a good penetration through the blood-brain barrier and thus a direct CNS challenge. ALCAR treatment produced no apparent change on CSF classic neurotransmitters and their metabolite levels (homovanillic acid, 5-hydroxyindoleacetic acid, MHPG, dopamine, choline). Among CSF peptides, while corticotropin-releasing hormone and adrenocorticotropic hormone remained unchanged, beta-endorphins significantly decreased after treatment; plasma cortisol levels matched this reduction. Since both CSF beta-endorphins and plasma cortisol decreased, one possible explanation is that ALCAR reduced the AD-dependent hypothalamic-pituitary-adrenocortical (HPA) axis hyperactivity. At present, no clear explanation can be proposed for the specific mechanism of this action.

Aspects of hypothalamic neuronal systems in VMH lesion-induced obese rats.

To clarify neuronal disturbance in the hypothalamus reflecting the development of obesity in ventromedial hypothalamic nucleus (VMH)-lesioned rats, we investigated the contents of neurotransmitters in the hypothalamus after pretreatment by microwave irradiation, contents of neurotransmitter metabolites in third ventricle fluid and catecholamine contents in the adrenal gland. The hypothalamic contents of norepinephrine (NE) and dopamine (DA) were selectively decreased, but acetylcholine (ACh) and serotonin (5-HT) levels were not changed from those in controls. In the lateral part of the hypothalamus, also, a significant decrease of NE content was detected. On the other hand, NE and DA metabolites, MHPG, DOPAC and HVA were increased in the third ventricle fluid in VMH lesion-induced obese rats. Wet weight and content of epinephrine in the adrenal gland were decreased, though the content of NE was preserved. These results indicate that a disturbance of NE and DA neurons in the hypothalamus is involved in the development of VMH lesion-induced obesity. In addition, an increment of the activities of NE and DA systems in the central nervous system as a whole and some irregularity in the sympatho-adrenal system might contribute to VMH obesity.

Evaluación del compromiso primario del sistema nervioso central: SNC; en la infección por el virus de la inmunodeficiencia humana, VIH-1, mediante el estudio del líquido cefalorraquídeo, LCR / Evaluation of the central nervous system primary involvement: CNS in HIV-1 infection utilizing cerebrospinal fluid; CSF, studies

Evaluamos el uso del líquido cefalorraquídeo (LCR) en el estudio del compromiso neurológico de tipo primario en la infección por VIH-1. Revisamos nuestros datos y los de trabajos relacionados al tema citados en el Index Medicus y publicados en español, inglés e italiano entre 1985-1991. Las alteraciones del LCR son frecuentes y precoces en la infección. La síntesis de IgG intratecal, índice de la respuesta inmunológica local anti-VIH, está alterada hasta en un 93% de los pacientes seropositivos al VIH-1 en etapas no SIDA. Los parámetros del estudio citoquímico básico como recuento celular de glóbulos blancos, niveles de glucosa y de proteína total del LCR son de mayor utilidad en el diagnóstico diferencial de complicaciones del SNC que en el diagnóstico de algún tipo particular de compromiso primario. Las alteraciones de neurotransmisores detectadas en el LCR, especialmente las concernientes al metabolismo del triptofano y el ácido quinolínico aportan a la comprensión de la patogénesis del complejo de demencia relacionado al SIDA. Los nuevos estudios en LCR de pacientes seropositivos están orientados a lograr un diagnóstico precoz y un control evolutivo más objetivo del compromiso neurológico primario cuantificando la carta viral mediante la pomymerase chain reaction (PCR). Otros investigadores estudian indicadores bioquímicos de la progresión sistémica de la infección, como neopterín, B2-microglobulina y citocinas como los eventuales predictores del compromiso neurológico, requeridos para una oportuna indicación y monitorización del tratamiento antiviral

Do concentrations of neurotransmitters measured in lumbar cerebrospinal fluid reflect the concentrations at brain level?

CSF concentrations of vasoactive intestinal polypeptide (VIP), cholecystokinin (CCK), noradrenaline (NA) and dopamine (DA) were measured in the lateral ventricles and at the lumbar level in patients with normal pressure hydrocephalus (NPH). The concentrations of VIP (n = 15), NA (n = 10) and DA (n = 10) were significantly higher at the lumbar level than at the ventricular level, whereas the concentrations of CCK (n = 9) were similar at the two sites. A significant positive correlation between the concentrations measured at the two levels was found for VIP (rs = 0.65; p less than or equal to 0.01) and DA (rs = 0.94; p less than or equal to 0.001). The results indicate that the concentrations of transmitter substances measured in CSF at the lumbar level not necessarily are indicative for concentrations measured more centrally. The negative correlations between Evans ratio and L-CSF VIP (rs = -0.76; p less than or equal to 0.001), and between resistance to outflow and V-CSF as well as L-CSF CCK (rs = -0.75); p less than or equal to 0.05) might be explained by a reduction in number of cortical neurons or by disturbances in CSF dynamics in patients with NPH.

Do concentrations of neurotransmitters in lumbar CSF reflect cerebral dysfunction in depression?

Concentrations of the amines and amine metabolites dopamine (DA), noradrenaline (NA), adrenaline (A), serotonin (5-HT), homovanillic acid (HVA), 3-methoxy-4-hydroxyphenylglycol (MHPG), 5-hydroxyindoleacetic acid (5-HIAA) and of the peptides, vasopressin (AVP), vasoactive intestinal polypeptide (VIP), thyrotropin releasing hormone (TRH) and cholecystokinin (CCK) were measured in lumbar cerebrospinal fluid (CSF) in patients with depression and compared with that of controls. Diagnostic classifications were performed according to ICD-9 and the Newcastle Rating Scales for Depression. The severity of depression was measured by Bech-Rafaelsen melancholia scale. Significantly decreased concentrations of CSF-A and AVP were found in as well endogenous as in non-endogenous depression, whereas reduced levels of CSF-VIP were found only in the non-endogenous group. CSF-5-HT and DA were significantly increased in endogenously depressed patients. In these studies patients with non-endogenous depression were not included. No relationship between severity of depression and concentrations of neurotransmitters was found. For most of the neurotransmitters no correlation between concentrations measured at the lumbar and at the ventricular level seems to exist. This finding indicates that measurements on CSF collected from the lumbar sack not necessarily are indicative for concentrations measured at more central levels. Although several transmitter systems most likely are disturbed in depression, results from studies on lumbar CSF should be interpreted with precaution, until further information about origin and distribution of neurotransmitters in CSF has been obtained.

Application of combined gas chromatography/mass spectrometry to neurotransmitter research.

The features of flexibility, sensitivity and specificity continue to make GC/MS a valuable technique for identification and quantification of neuro-transmitters and related compounds. In this report four recent examples are presented which highlight the potentials of this technique. The traditional concept that GC/MS equipment is expensive and complex to operate warrants reconsideration in light of recent manufacturing trends in automation, computerization and the introduction of cheaper bench-top models.

Biopterin and neurotransmitter amine metabolism in children with acute lymphoblastic leukemia receiving methotrexate therapy.

To test the hypothesis that some of the neurologic sequelae of treatment for acute lymphoblastic leukemia (ALL) might be related to abnormalities in biopterin metabolism associated with methotrexate (MTX) therapy, total biopterin levels in cerebrospinal fluid (CSF) and plasma, and homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5HIAA) were measured in a cross-sectional study of 80 children with ALL. For comparison, biopterins were also measured in a group of children of similar age undergoing investigation for neurologic disease. In children with ALL studied before therapy, no significant difference was found between the means of plasma biopterin or CSF biopterin concentrations and the means in the control group. In children receiving MTX, plasma biopterin values were higher in the group given maintenance therapy than in children observed before treatment. CSF levels were significantly increased only in those patients who had completed 2 years of maintenance therapy. CSF concentrations of HVA and 5HIAA in patients with ALL who had received no treatment (median values 52 and 18 ng/ml, respectively) showed a wide scatter and were inversely related to age. In patients receiving MTX, concentrations of these metabolites were higher than in the untreated group, again reaching a peak in patients just completing 2 years of treatment (median HVA 110 ng/ml, 5HIAA 34 ng/ml). These results provide no support for the idea that neurotransmitter amine deficiency occurs in children with ALL receiving MTX, and indicate, rather, that amine and biopterin synthesis increases in such patients.

CSF neurotransmitter markers in Alzheimer's disease.

CSF neurotransmitter markers may reflect neurochemical alterations in Alzheimer's disease (AD). The best studied neurochemical deficit in AD is that of acetylcholine. Both acetylcholinesterase and butyrylcholinesterase activity have been reported to be reduced in some but not all studies of AD CSF. Studies of monoamine metabolites have also been controversial but most authors have found reduced concentrations of CSF HVA, lesser reductions in HIAA and no change in MHPG. CSF GABA concentrations have been found to be reduced in AD. Studies of CSF neuropeptides in AD have shown reduced concentrations of somatostatin and vasopressin, normal concentrations of vasoactive intestinal polypeptide and either normal or decreased concentrations of beta-endorphin and corticotropin releasing factor. Although no individual CSF neurochemical markers are specific for AD it may be possible to develop a profile of several neurochemical markers which will have enhanced specificity.