Delphi consensus on recommendations for the treatment of spinal muscular atrophy in Spain (RET-AME consensus).

INTRODUCTION: Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by a biallelic mutation of the SMN1 gene, located on the long arm of chromosome 5, and predominantly affects the motor neurons of the anterior horn of the spinal cord, causing progressive muscle weakness and atrophy. The development of disease-modifying treatments is significantly changing the natural history of SMA, but uncertainty remains about which patients can benefit from these treatments and how that benefit should be measured. METHODOLOGY: A group of experts specialised in neurology, neuropediatrics, and rehabilitation and representatives of the Spanish association of patients with SMA followed the Delphi method to reach a consensus on 5 issues related to the use of these new treatments: general aspects, treatment objectives, outcome assessment tools, requirements of the treating centres, and regulation of their use. Consensus was considered to be achieved when a response received at least 80% of votes. RESULTS: Treatment protocols are useful for regulating the use of high-impact medications and should guide treatment, but should be updated regularly to take into account the most recent evidence available, and their implementation should be assessed on an individual basis. Age, baseline functional status, and, in the case of children, the type of SMA and the number of copies of SMN2 are characteristics that should be considered when establishing therapeutic objectives, assessment tools, and the use of such treatments. The cost-effectiveness of these treatments in paediatric patients is mainly influenced by early treatment onset; therefore, the implementation of neonatal screening is recommended. CONCLUSIONS: The RET-AME consensus recommendations provide a frame of reference for the appropriate use of disease-modifying treatments in patients with SMA.

Brainstem dysgenesis: beyond Moebius syndrome. / Disgenesia troncoencefalica: mas alla del sindrome de Moebius.

Brainstem dysgenesis designates all those patients with congenital dysfunction of cranial nerves and muscle tone due to prenatal lesions or malformations of the brainstem. This generic term has the advantage over the eponyms Moebius 'expanded' or 'unrestricted', Robin, Cogan or Carey-Fineman-Ziter syndromes in that it has a less restrictive view and provides a frame work that enables a systematic approach to diagnosis and research of most developmental disorders involving the brainstem. The review of the literature and our experience shows that infants with a predominant rombencephalic involvement are due to brainstem prenatal disruptive vascular accidents, while cases with midbrain and cerebellar involvement and widespread malformative syndromes have most likely an underlying genetic cause. Due to phenotypic heterogeneity associated with brainstem dysgenesis, it is crucial to evaluate each case individually and to establish a specific therapeutic plan. Intervention programs should start soon after diagnosis and directed to improve functions needed for daily life activities. Even though the prognosis of patients with brainstem dysgenesis due to prenatal destructive lesions depends on the magnitude of the vascular territory involved, in most patients with brainstem dysgenesis, the prognosis is better than the initial clinical manifestations would indicate.

TITLE: Disgenesia troncoencefalica: mas alla del sindrome de Moebius.El termino 'disgenesia troncoencefalica' se aplica a los pacientes que presentan afectacion congenita de multiples pares craneales, hipotonia muscular y signos leves de afectacion de la via piramidal. Este termino es ventajoso respecto al uso de eponimos tales como Moebius, Robin, Cogan y Carey-Fineman-Ziter, ya que es menos restrictivo y ofrece un nuevo enfoque para comprender las causas y su patogenia, asi como para mejorar el tratamiento de este grupo de alteraciones del desarrollo que afectan exclusiva o predominantemente al tronco del encefalo. La revision de la bibliografia y nuestra experiencia muestran que la mayoria de los casos con afectacion selectiva del rombencefalo se deben a lesiones disruptivas prenatales, mientras que en los casos con afectacion del mesencefalo y el cerebelo, asi como en los sindromes polimalformativos con afectacion destacada del troncoencefalo, la topografia de las lesiones es mas difusa y menos especifica, y la causa hereditaria, mas probable. Debido a la amplia heterogeneidad fenotipica asociada a la disgenesia troncoencefalica, es esencial realizar una evaluacion individualizada y establecer un plan de tratamiento especifico. Los programas de rehabilitacion deben comenzar poco despues del diagnostico y centrarse en mejorar las habilidades motoras, dotando al paciente de las herramientas necesarias para afrontar las necesidades diarias en funcion de la morbilidad asociada. Aunque el pronostico de la disgenesia troncoencefalica secundaria a lesiones disruptivas depende de la localizacion y la extension del territorio vascular afectado, en general, el pronostico de los pacientes con disgenesia troncoencefalica es mejor de lo que las manifestaciones clinicas iniciales harian suponer.

[The pattern of DNA fragmentation in pediatric neuromuscular disorders]. / Análisis del patrón de fragmentación del ADN en enfermedades neuromusculares pediátricas.

INTRODUCTION: An apoptotic mode of cell death has been identified in the developing skeletal muscle of invertebrates. It has been also involved in the pathogenesis of muscle degeneration in the dystrophin-deficient mdx mouse. This has raised an interest on the possible role of apoptosis in human neuromuscular disorders, but the existing studies have offered conflicting results. OBJECTIVE: To analyze the presence of apoptosis in several pediatric neuromuscular disorders. PATIENTS AND METHODS: Identification of cells with apoptotic morphology, detection of DNA fragmentation in situ by means of the TUNEL assay and study of the pattern of DNA fragmentation by agarose gel electrophoresis and Southern blot hybridization in muscle biopsies of 29 patients and three normal controls. RESULTS: No morphological features of apoptosis were found in any of the samples examined. The TUNEL method did not label the myonuclei from any of the biopsies, though some mastocytes stained positively. Agarose gel electrophoresis of extracted DNA and Southern blot hybridization with a genomic DNA probe did not show oligonucleosomal fragmentation. However, smearing of DNA was observed in samples from three patients affected with Duchenne's muscular dystrophy, one with Becker's muscular dystrophy and one with infantile spinal muscular atrophy. CONCLUSIONS: The present results do not favor the hypothesis of persistent apoptosis in some of the pediatric neuromuscular disorders, although they do not exclude that some sort of programmed cell death occurs either excessively or anachronically at other stages of the pathogenesis of these diseases.

Meiotic arrest and germ cell apoptosis in androgen-binding protein transgenic mice.

The fundamental role of androgen-binding protein (ABP) in spermatogenesis remains obscure after nearly 25 yr since its first characterization. In the present investigation, we used a transgenic mouse model that overexpresses rat ABP to examine the potential involvement of this protein in the regulation of processes occurring during spermatogenesis. Specifically, homozygous or heterozygous transgenic mice were analyzed in terms of spermatogenic progression, DNA fragmentation pattern, and germinal cell ploidy status. All animals homozygous for transgenic ABP exhibited an increased accumulation of primary spermatocytes and cells at metaphase with abnormal morphology and localization within the seminiferous epithelium. Analysis of DNA fragmentation by in situ techniques and agarose gel electrophoresis provided evidence for an increased occurrence of apoptosis in the transgenic animals, principally involving pachytene spermatocytes and cells at metaphase. Flow cytometric analysis of the DNA content of isolated germ cells revealed a reduction in the number of haploid cells, an increase in the number of tetraploid cells, and the appearance of a hypotetraploid cell population, consistent with degenerating primary spermatocytes. In mice heterozygous for the transgene, the effects were less prominent, and the degree to which spermatogenesis was compromised correlated with the levels of ABP messenger RNA in individual animals. The present results are interpreted to suggest that ABP can act as a modulator of spermatogenesis by regulating completion of the first meiotic division of primary spermatocytes.

Clinical relevance of molecular markers in neuroblastoma: results from a single institution.

Neuroblastomas, the most common extracranial solid tumors in children, present an extremely heterogeneous behaviour that can be explained in part by their genetic abnormalities. Thirty-four patients treated at the Pediatric Oncology Unit, Hospital Vall d'Hebron from 1993 to 1997 were prospectively studied to determine the relative prognostic impact of a number of clinical and molecular factors. The factors studied were: ploidy, MYCN and 1p status, and TRK-A expression, in addition to age, stage and histology. Their impact on prognosis was analyzed. In univariate analysis, advanced stage, unfavorable histology, diploidy, MYCN amplification, and 1p deletion were identified as adverse prognostic factors; TRK-A expression was associated with favorable prognosis. After multivariate analysis, only MYCN amplification proved to be an independent adverse prognostic factor (p=0.03), whereas TRK-A expression identified a subset of good-prognosis patients (p=0.003).

Differential polymerase chain reaction with serial dilutions for quantification of MYCN gene amplification in neuroblastoma.

BACKGROUND: MYCN amplification is a powerful prognostic marker in neuroblastoma. Since MYCN status guides therapy results should be available promptly after diagnosis. MATERIAL AND METHODS: We used a differential PCR assay to analyze neuroblastoma samples obtained from 25 patients diagnosed and treated at our Institution. Serial dilutions of test DNA in control DNA were performed prior to differential PCR in order to quantitate the MYCN copy number. RESULTS: MYCN amplification was identified by differential PCR in five samples out of twenty five. The serial dilutions of amplified DNAs performed before the PCR reaction allowed a precise estimation of the copy number in the 5 samples with amplification. CONCLUSIONS: The present results confirm differential PCR assay as an easy, sensitive and rapid technique to evaluate the MYCN gene amplification in neuroblastoma. Serial dilutions accurately estimate the gene copy number allowing the early onset of the appropriate treatment.

Cell death and associated c-jun induction in perinatal hypoxia-ischemia. Effect of the neuroprotective drug dexamethasone.

Previous studies in a model of unilateral hypoxia-ischemia in the developing rat brain have shown induction of the mRNAs of c-fos and c-jun and presence of apoptotic DNA fragmentation. In this same model, dexamethasone confers neuroprotection if given before the insult. Since c-fos and c-jun have been involved in several models of cell death, we investigated whether the neuroprotective effect of dexamethasone could be associated with changes in expression of these genes. Rat pups, pre-treated with either 0.5 mg/kg dexamethasone or vehicle 48 h, 24 h and immediately before the injury, were subjected to ligation of the left common carotid artery followed by 3 h hypoxia. Analysis of c-fos and c-jun expression at 2 h, by means of in situ hybridization, revealed diminished induction in dexamethasone-treated animals. Jun immunoreactivity, but not Fos, and DNA fragmentation, assessed by in situ end-labeling of fragmented DNA, were present at 24 h only in vehicle-injected animals. Electrophoresis of brain extracted DNA revealed a ladder pattern in all the animals. Our results show a relationship between Jun overexpression and cell-death in the hypoxic-ischemic developing brain and suggest that dexamethasone exerts its protective effect anteceding immediate early gene induction, at some early point in post-ischemic signal transduction.

Identification of necrotic cell death by the TUNEL assay in the hypoxic-ischemic neonatal rat brain.

The time course and localization of DNA fragmentation in a neonatal rat model of unilateral hypoxia-ischemia were assessed by means of the terminal transferase-mediated biotin dUTP nick end labeling (TUNEL) assay. TUNEL-positive cells were detected in the hemisphere ipsilateral to the ligation immediately after the injury and increased to reach a maximum 1-3 days later, then decreasing until day 10, in parallel with cell death identified by standard histological methods. Cells showing any of the different morphologies of chromatin condensation and fragmentation were labeled, particularly within the core of the ischemic lesion. These results, obtained in a paradigm of necrosis in the immature brain, add to previous evidence suggesting that some forms of non-apoptotic DNA fragmentation are labeled by the TUNEL assay.

[Molecular factors of cerebral hypoxia-ischemia]. / Factores moleculares en la hipoxia-isquemia cerebral.

In recent years much has been learned about the cellular and molecular events underlying cerebral hypoxia-ischemia (HI). We review, from a molecular standpoint, the main pathogenetic theories in hypoxic-ischemic cerebral injury, including excitotoxicity, free radical damage, and the role of growth factors, proto-oncogenes and heat shock proteins. The various forms of cell death in the developing and adult brain (necrosis, apoptosis and delayed neuronal death) are reviewed, with an emphasis on gene regulation of naturally-occurring and HI-associated cell death. We report the expression of the immediate early gene c-fos and c-jun mRNAs and of HSP72 mRNA and protein in several models of cerebral HI. Gel agarose electrophoresis of extracted DNA and in situ end-labeling of fragmented DNA revealed that cell death in these models was associated with endonuclease(s) activation. We also pre-treated some animals with dexamethasone, a neuroprotective drug in a model of perinatal HI. High-dose dexamethasone prevented c-fos induction in cerebral regions sensitive to HI. This effect may be due to a functional antagonism, at the transcriptional level, between Fos and the glucocorticoid receptor.

Evidence of internucleosomal DNA fragmentation and identification of dying cells in X-ray-induced cell death in the developing brain.

Newborn Sprague-Dawley rats received a single dose of 2 Gy X-rays and were killed 6 hr later. Dying cells were characterized by extreme chromatin condensation and nuclear fragmentation. Dying cells were distributed in the primary and secondary germinal zones and in other brain regions. Among these latter, dying cells occurred in the cortical layers of the olfactory bulb, layers II-III and VIb of the neocortex, piriform and entorhinal cortex, stratum oriens and pyramidale of the hippocampus, striatum, thalamus, amygdala, brainstem, internal granular layer of the cerebellum, and cerebral and cerebellar white matter. Dying cells were immature cells, neurons and glial cells (including radial glia). In-situ labeling of nuclear DNA fragmentation identified individual cells bearing fragmented DNA. Since the number of cells stained with this method was larger than the number of dying cells, as revealed with current histological techniques, it is suggested that nuclear DNA fragmentation precedes chromatin condensation and nuclear fragmentation in X-ray-induced apoptosis. Furthermore, agarose gel electrophoresis of extracted DNA from irradiated brains showed a "ladder" pattern which is typical of internucleosomal DNA fragmentation and endonuclease activation.

Apoptosis in substantia nigra following developmental striatal excitotoxic injury.

We have previously observed that an axon-sparing injury to the developing striatum induced by the excitotoxin quinolinate results in a decrease in dopaminergic neurons in the substantia nigra pars compacta (SNpc) of the adult. This decrease occurs in the absence of direct injury to the SNpc. As the striatum is a major target for the SNpc dopaminergic system, we have hypothesized that a decrease in the size of the striatal target during development may result in an induced regressive event in the SNpc, similar to what has been described for many developing neural systems with peripheral targets. We have examined by morphologic and biochemical means the time course and character of cell death in SN following a unilateral striatal lesion with quinolinate in immature rats. The striatal lesion is associated with an induced cell death event in the ipsilateral SN, observed first in SNpc and then in SN pars reticulata. The morphologic characteristics of the dying cells were typical of apoptosis. Immunostaining for tyrosine hydroxylase indicated that some of the apoptotic cells in the SNpc were dopaminergic. We conclude that developmental striatal excitotoxic injury is associated with induced apoptotic cell death in SN.

Evidence of nuclear DNA fragmentation following hypoxia-ischemia in the infant rat brain, and transient forebrain ischemia in the adult gerbil.

Wistar rats, eight days old, were subjected to permanent bilateral forebrain ischemia, followed by hypoxia for 15 minutes. A cerebral infarct, mainly involving the cerebral neocortex, hippocampus, amygdala, striatum and subcortical white matter was produced. Neurons and glia showing punctate chromatin condensation and karyorrhectic cells were observed 12 hours after hypoxia-ischemia. Their number increased during the first two days and recruitment of cells with degenerating nuclei occurred until day five. In situ labeling of nuclear DNA fragmentation stained many normal-appearing nuclei, as well as punctate chromatin condensations and nuclear fragments in karyorrhectic cells. Delayed neuronal death in the CA1 area of the hippocampus was observed after 20 minutes of transient forebrain ischemia in the adult gerbil. In situ labeling of nuclear DNA fragmentation demonstrated stained punctate chromatin condensation in a few degenerating cells at 48 hours post-ischemia. Substantial labeling of CA1 neurons occurred in the fourth day. Agarose gel electrophoresis of extracted brain DNA from ischemic infant rats and adult gerbils showed a ladder-type pattern which is typical of nuclear DNA fragmentation into oligonucleosomal fragments (internucleosomal cleavage). These findings suggest that endonuclease(s) activation may play a role in cell death induced by different forms of hypoxia-ischemia.

Localization of c-fos, c-jun, and hsp70 mRNA expression in brain after neonatal hypoxia-ischemia.

The sites of expression of early response mRNAs were determined in the brains of 7-day-old rat pups exposed to unilateral carotid artery ligation followed by 3 h of hypoxia. Pups were sacrificed after recovery periods ranging from 10 min to 24 h. In agreement with our previous northern blot analysis, in situ hybridization of coronal brain sections to probes for c-fos, c-jun, and heat-inducible hsp70 revealed a marked induction and subsequent disappearance of all three mRNAs during this time period. We observed co-localization of the 2 immediate early gene (IEG) mRNAs, c-fos and c-jun, which encode proteins that act in combination to regulate subsequent gene expression. These mRNAs were expressed in all regions known to be vulnerable to permanent injury in this model, such as the cortex, hippocampus, and striatum, as well as in other regions that are spared from permanent damage, such as contralateral cortex and lateral ventricular neuroepithelium. The temporal and regional co-localization of c-fos and c-jun suggests that the transcriptional regulatory activity of their protein products could play a role in plasticity associated with death or recovery from injury in the immature brain. Hsp70 mRNA expression was induced in nearly all of the animals that were positive for IEG mRNAs. Although the most frequent site of expression for all three mRNAs was the ipsilateral cerebral cortex, hsp70 expression was restricted to the ipsilateral hemisphere and absent from a number of structures that were positive for c-fos and c-jun. In addition, the patterns of expression of hsp70 within specific structures frequently differed from those of the IEGs, implying that although both cellular early response systems are activated in this model, their specific functions are carried out within different microenvironments.

Immediate early gene induction after neonatal hypoxia-ischemia.

Immediate early gene (IEG) products, such as FOS and JUN, may partially mediate the long-term transcriptional response of CNS cells to specific changes in their environment. To determine whether IEG products might be involved in the immature brain's response to hypoxia-ischemia (H-I), 7-day-old rat pups were subjected to unilateral common carotid artery ligation followed by 3 h of hypoxia (8% O2/92% N2) at 37 degrees C, which results in pathological changes only in specific regions of the hemisphere ipsilateral to ligation. Time course experiments were performed, in which animals were sacrificed between 1 and 24 h after H-I. RNAs from several brain regions were analyzed by Northern blot hybridization for their relative concentrations of nine IEG mRNAs (c-fos, c-jun, junB, TIS 1 (nur77), TIS7, TIS8 (zif268), TIS10, TIS11, and TIS21). Induction of all IEGs, except TIS7 and TIS10, was observed in ipsilateral forebrain, and, less frequently, in contralateral forebrain, at 1, 2, and 3 h post-hypoxia. In some animals, lower levels of expression were also detected at 4, 18 and 24 h. With minor exceptions, co-induction of all seven IEGs was observed in a given RNA sample. Induction of two other mRNAs, representing the heat shock and astrocytic responses, were also observed. Hsp70 mRNA levels were increased only in the brains of animals exhibiting IEG induction. However, hsp70 induction was confined to the ipsilateral forebrain, implying a more direct relationship between its expression and permanent morphological damage. GFAP mRNA induction occurred predominantly in ipsilateral forebrain samples at 18 and 24 h post-hypoxia. Levels of B-actin and ubiquitin mRNAs were relatively constant in the same RNA samples. In control experiments c-fos mRNA induction was not detected after sham ligation with hypoxia, ligation with sham hypoxia, or hypoxia alone. These results suggest that the immature brain is highly responsive to H-I at the level of gene expression, involving at least three different rapid response systems.

Disorders of movement in Leigh syndrome.

Leigh syndrome (LS) is the clinical prototype of a genetically-determined mitochondrial encephalopathy. Twenty-two of 34 patients with LS had evidence of a movement disorder (MD). Dystonia, the most common MD, was present in 19 cases, rigidity in 4, tremor in 2, chorea in 2, hypokinesia in 2, myoclonus in 1, and tics in 1. Dystonia was most commonly multifocal at onset and showed progression in six patients. In half of the cases an enzymatic defect was detected, most commonly cytochrome C oxidase. The neuroradiologic findings showed prominent basal ganglia lesions in 20/21 patients. Putamen, caudate, substantia nigra and globus pallidus were involved in this order of frequency. This experience was reflected in a literature review encompassing 284 cases of LS. However, only 26.4% had MD. Eleven patients, including one of our cases, presented as the primary torsion dystonia phenotype. There are clinical and pathological similarities between LS and other metabolic diseases affecting the central nervous system. The enhanced vulnerability of the nervous system to metabolic stress and the resemblance in the distribution of the pathology of these diverse conditions suggests a common pathogenetic mechanism. An excitotoxin-mediated mechanism is favored, one which might account for the frequent involvement of the basal ganglia in LS.

Altered genetic response to beta-adrenergic receptor activation in late passage C6 glioma cells.

Previous studies have demonstrated variability in the phenotype of rat C6 glioma cells. In the present study, we compared morphology, growth rate, and beta-adrenergic regulation of gene expression in early (P39-47) and late (P55-90) passage C6 cells. Morphological changes were observed in five independently derived, late passage populations. In four of the five, the untreated cells were more polygonal than the fibroblast-like parental cells, and only a small fraction exhibited process outgrowth after dbcAMP treatment. Untreated cells from the fifth late passage population had longer cytoplasmic processes than parental cells and responded to dbcAMP with further process outgrowth. All late passage populations had shorter generation times than the parental cells. In early passage cells, treatment with the beta-adrenergic agonist, isoproterenol (IPR), resulted in an increase in c-fos mRNA and a decrease in c-jun mRNA (Gu-bits RM, Yu H: J Neurosci Res, 30:625-630, 1991). Both of these immediate early gene responses were irreversibly lost between P50 and P55. Additional differences in basal or IPR-induced mRNA levels were observed for beta-APP, GFAP, NGF, and PPE, but not for a number of other mRNAs. These results are discussed in relationship to previously described differences in the ability of early and late passage C6 cells to accumulate cAMP (Mallorga P, et al.: Biochim Biophys Acta 678:221-229, 1981).