Marital status is a prognostic factor in amyotrophic lateral sclerosis

BACKGROUND AND OBJECTIVES

Several variables have been linked to a shorter survival in patients with amyotrophic lateral sclerosis (ALS), for example, female sex, older age, site of disease onset, rapid disease progression, and a relatively short diagnostic delay. With regard to marital status, previous studies suggested that living with a partner might be associated to a longer survival and a higher likelihood to proceed to tracheostomy. Therefore, to further strengthen this hypothesis, we investigated the role of marital status as a prognostic variable in a cohort of ALS patients.

METHODS

We performed a retrospective analysis on 501 consecutive ALS patients for which a complete disease's natural history and clinical/demographic data were available. At diagnosis, 409 patients (81.6%) were married or lived with a stable partner, whereas 92 patients (18.4%) were single/widowed/divorced.

RESULTS

In our ALS cohort, being married was associated with a median longer survival (married, 35 months [24-50] vs unmarried, 27 months [18-42]; P<.004). Moreover, married and unmarried patients were significantly different in many clinical and demographic variables, including age at disease onset, gender, body mass index, and number of children. Cox regression analysis showed that age at onset, diagnostic delay, and marital status were independent predictors of survival. In unmarried patients, female sex was also significantly associated with shorter survival.

CONCLUSIONS

Marital status is a prognostic factor in ALS, and it significantly affects survival.

REM sleep behavior disorder and periodic leg movements during sleep in ALS

OBJECTIVE

To assess sleep characteristics and the occurrence of abnormal muscle activity during sleep, such as REM sleep without atonia (RSWA), REM sleep behavior disorder (RBD), and periodic leg movements during sleep (PLMS), in patients with amyotrophic lateral sclerosis (ALS).

METHODS

A total of 41 patients with ALS and 26 healthy subjects were submitted to clinical interview and overnight video-polysomnography.

RESULTS

A total of 22 patients with ALS (53.6%) reported poor sleep quality. Polysomnographic studies showed that patients with ALS had reduced total sleep time, increased wakefulness after sleep onset, shortened REM and slow-wave sleep, and decreased sleep efficiency, compared to controls. Polysomnographic abnormalities were not different in patients reporting good or poor sleep and were not correlated to clinical and demographic variables. The PLMS index was significantly higher in patients with ALS than in healthy subjects, and 22 patients (53.6%) showed a PLMS index > 15/h, vs 4 (15.4%) controls (P < 0.001). Finally, two patients with ALS (4.9%) had RBD, and two more patients presented RSWA (4.9%), whereas no controls showed abnormalities of REM sleep.

CONCLUSION

Patients with ALS frequently present abnormalities of sleep that can be documented both at the clinical interview and at the polysomnographic evaluation, including insomnia, fragmented sleep, and increased PLMS. Moreover, abnormalities of REM sleep can be found in some of these patients.

Tauroursodeoxycholic acid in the treatment of patients with amyotrophic lateral sclerosis

Background and purpose

Tauroursodeoxycholic acid (TUDCA) is a hydrophilic bile acid that is produced in the liver and used for treatment of chronic cholestatic liver diseases. Experimental studies suggest that TUDCA may have cytoprotective and anti‐apoptotic action, with potential neuroprotective activity. A proof of principle approach was adopted to provide preliminary data regarding the efficacy and tolerability of TUDCA in a series of patients with amyotrophic lateral sclerosis (ALS).

Methods

As a proof of principle, using a double‐blind placebo controlled design, 34 ALS patients under treatment with riluzole who were randomized to placebo or TUDCA (1 g twice daily for 54 weeks) were evaluated after a lead‐in period of 3 months. The patients were examined every 6 weeks. The primary outcome was the proportion of responders [those subjects with improvement of at least 15% in the Amyotrophic Lateral Sclerosis Functional Rating Scale Revised (ALSFRS‐R) slope during the treatment period compared to the lead‐in phase]. Secondary outcomes included between‐treatment comparison of ALSFRS‐R at study end, comparison of the linear regression slopes for ALSFFRS‐R mean scores and the occurrence of adverse events.

Results

Tauroursodeoxycholic acid was well tolerated; there were no between‐group differences for adverse events. The proportion of responders was higher under TUDCA (87%) than under placebo (P = 0.021; 43%). At study end baseline‐adjusted ALSFRS‐R was significantly higher (P = 0.007) in TUDCA than in placebo groups. Comparison of the slopes of regression analysis showed slower progression in the TUDCA than in the placebo group (P < 0.01).

Conclusions

This pilot study provides preliminary clinical data indicating that TUDCA is safe and may be effective in ALS.

Click here to view the accompanying paper in this issue.

The eye-tracking computer device for communication in amyotrophic lateral sclerosis

OBJECTIVE

To explore the effectiveness of communication and the variables affecting the eye-tracking computer system (ETCS) utilization in patients with late-stage amyotrophic lateral sclerosis (ALS).

METHODS

We performed a telephone survey on 30 patients with advanced non-demented ALS that were provisioned an ECTS device. Median age at interview was 55 years (IQR = 48-62), with a relatively high education (13 years, IQR = 8-13). A one-off interview was made and answers were later provided with the help of the caregiver. The interview included items about demographic and clinical variables affecting the daily ETCS utilization.

RESULTS

The median time of ETCS device possession was 15 months (IQR = 9-20). The actual daily utilization was 300 min (IQR = 100-720), mainly for the communication with relatives/caregiver, internet surfing, e-mailing, and social networking. 23.3% of patients with ALS (n = 7) had a low daily ETCS utilization; most reported causes were eye-gaze tiredness and oculomotor dysfunction.

CONCLUSIONS

Eye-tracking computer system is a valuable device for AAC in patients with ALS, and it can be operated with a good performance. The development of oculomotor impairment may limit its functional use.

Genetic counselling in ALS: facts, uncertainties and clinical suggestions

The clinical approach to patients with amyotrophic lateral sclerosis (ALS) has been largely modified by the identification of novel genes, the detection of gene mutations in apparently sporadic patients, and the discovery of the strict genetic and clinical relation between ALS and frontotemporal dementia (FTD). As a consequence, clinicians are increasingly facing the dilemma on how to handle genetic counselling and testing both for ALS patients and their relatives. On the basis of existing literature on genetics of ALS and of other late-onset life-threatening disorders, we propose clinical suggestions to enable neurologists to provide optimal clinical and genetic counselling to patients and families. Genetic testing should be offered to ALS patients who have a first-degree or second-degree relative with ALS, FTD or both, and should be discussed with, but not offered to, all other ALS patients, with special emphasis on its major uncertainties. Presently, genetic testing should not be proposed to asymptomatic at-risk subjects, unless they request it or are enrolled in research programmes. Genetic counselling in ALS should take into account the uncertainties about the pathogenicity and penetrance of some genetic mutations; the possible presence of mutations of different genes in the same individual; the poor genotypic/phenotypic correlation in most ALS genes; and the phenotypic pleiotropy of some genes. Though psychological, social and ethical implications of genetic testing are still relatively unexplored in ALS, we recommend multidisciplinary counselling that addresses all relevant issues, including disclosure of tests results to family members and the risk for genetic discrimination.

Expression of vesicle-associated membrane-protein-associated protein B cleavage products in peripheral blood leukocytes and cerebrospinal fluid of patients with sporadic amyotrophic lateral sclerosis

BACKGROUND AND PURPOSE

Vesicle-associated membrane-protein-associated protein B (VAPB) is an endoplasmic reticulum (ER) resident protein participating in ER function, vesicle trafficking, calcium homeostasis and lipid transport. Its N-terminal domain, named MSP, is cleaved and secreted, serving as an extracellular ligand. VAPB mutations are linked to autosomal-dominant motor neuron diseases, including amyotrophic lateral sclerosis (ALS) type 8. An altered VAPB function is also suspected in sporadic ALS (SALS).

METHODS

The expression pattern of VAPB cleavage and secreted products in the peripheral blood leukocytes (PBL) and cerebrospinal fluid (CSF) of SALS patients and neurological controls was assessed. PBL from healthy controls were also analyzed. Assays were carried out through western blotting, using an anti-VAPB (N-terminal) antibody.

RESULTS

Two VAPB fragments containing the MSP domain (17 kDa and 14 kDa molecular sizes) were identified in PBL of SALS and controls, with no significant differences amongst groups. In CSF, only the 14 kDa VAPB MSP fragment was expressed and a corresponding VAPA fragment was not detected. The CSF VAPB fragment was absent in 58.7% of SALS patients, of whom 79.2% were bulbar onset (P = 0.001, bulbar versus spinal).

CONCLUSIONS

The absence of the CSF VAPB MSP fragment from most bulbar-onset SALS patients suggests a specific alteration of brain-derived VAPB cleavage and secretion in this group of patients, and hints at a role of VAPB in the pathophysiology of this motor neuron disease.

Fatigue, sleep, and nocturnal complaints in patients with amyotrophic lateral sclerosis

BACKGROUND AND PURPOSE

Fatigue is a common symptom in amyotrophic lateral sclerosis (ALS). Although sleep disturbances are a candidate factor that may interfere with fatigue in patients with ALS, the role of sleep-related abnormalities in determining fatigue in ALS is unknown.

OBJECTIVE

To evaluate the frequency and determinants of fatigue in a group of 91 consecutive patients with ALS, with special attention to the relationship between fatigue and sleep problems.

METHODS

Measures included the Fatigue Severity Scale (FSS), Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), ALS Functional Rating Scale-Revised (ALSFRS-R), and Beck Depression Inventory (BDI).

RESULTS

  The mean FSS score was 4.35 ± 1.1, and 48 patients with ALS (52.75%) reported clinical significant fatigue. FSS score correlated with ALSFRS-R score, forced vital capacity, ESS, BDI, and global PSQI score. Patients with fatigue were significantly more disabled and more frequently reported difficulties staying asleep and nocturnal complaints, such as nocturia and disturbing muscle cramps. After multivariate analysis, patients' disability and nocturnal complaints were significantly associated with fatigue.

CONCLUSION

  In this study, we demonstrated that fatigue, a troublesome and disabling symptom in ALS, is associated with physical impairment and night-time complaints (such as nocturia and muscle cramps), suggesting that treating sleep problems might be useful in alleviating fatigue in these patients.

Causes and place of death in Italian patients with amyotrophic lateral sclerosis

OBJECTIVES

To determine the causes and place of death in a cohort of Italian patients with amyotrophic lateral sclerosis (ALS). A better understanding of the likely causes of death in ALS might improve the palliative care at the end-of-life, whereas knowing the place of death will help to verify the need for highly specialized care services, e.g. hospice and nursing home.

PATIENTS AND METHODS

Between 2000 and 2008, 182 ALS patients (onset: spinal, 127; bulbar, 55; M/F: 1.6) were followed in a single ALS Tertiary Centre in Palermo, Sicily, Italy until death. Medical data for each individual patient were recorded in a large database throughout the disease course. Information concerning causes and place of death were obtained by consultation with relatives or the family physician.

RESULTS

Respiratory failure (terminal respiratory insufficiency, pneumonia) was the most frequent cause of death (81.3%), which included six cases (3.3%) who requested a terminal sedation. Sudden death and death during sleep accounted for by 6.0% and 6.6% of all deaths, respectively. Heart-related causes of death were relatively infrequent in our cohort, accounting for by 7.1% of all deaths (i.e. sudden death: 6.0% and myocardial infarct: 1.1%). Patients (85.2%) died at home.

CONCLUSIONS

The leading cause of death in ALS remains the respiratory failure, followed by the sudden death and death during sleep. Most patients in our cohort died at home, a choice that might be only partially driven by cultural factors. These findings might have a great impact on the development of the advanced and end-of-life palliative care and in the planning of specialized care services, as hospice and nursing home.

Elevated cerebrospinal fluid and plasma homocysteine levels in ALS

BACKGROUND

High cerebrospinal fluid (CSF) and plasma levels of homocysteine (HC) have been reported in certain neurodegenerative disorders, such as Alzheimer's, Parkinson's diseases and, recently, amyotrophic lateral sclerosis (ALS).

OBJECTIVES

To assay the CSF and plasma levels of HC in ALS patients and controls, and to evaluate the relationship between HC levels and clinical variables of the disease.

METHODS

Cerebrospinal fluid from sixty-nine (M/F 1.87) and plasma from sixty-five ALS patients (M/F 1.83) were taken and stored at -80 degrees C until use. Controls (CSF = 55; plasma = 67) were patients admitted to our hospital for neurological disorders with no known relationship to HC changes. CSF and plasma from ALS patients and controls were obtained as a necessary step of the diagnostic workup. HC levels in CSF and plasma were assayed using a high performance liquid chromatograph (HPLC) and a fluorimeter detector.

RESULTS

The median level of total HC in the CSF of ALS patients was 0.46( )microM, significantly higher than that of the controls (0.24 microM, +91.6%, P < 0.001). A similar trend was observed when HC was assayed in plasma (ALS, 12.4 microM vs. controls, 7.26 microM, +70.8%, P < 0.001). The CSF and plasma HC levels showed no relationship with the disease progression, age at onset, and the site of onset.

CONCLUSIONS

Homocysteine is a biochemical marker in ALS, and it might be related to the pathophysiology of the disease.

Cerebrospinal fluid tau protein is not a biological marker in amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder leading to progressive motor neuron cell death. Etiopathogenesis is still imperfectly known and much effort have been undertaken to find a biological marker that could help in the early diagnosis and in the monitoring of disease progression. Cerebrospinal fluid (CSF) concentrations of tau, an axonal microtubule-associated protein, have been measured in ALS with levels found increased in some studies and unchanged in others.

METHODS

Total CSF tau level was assayed in a population of ALS patients (n = 57) and controls (n = 110) using a specific ELISA method.

RESULTS

No significant differences in the median CSF tau levels between ALS cases and controls were found [ALS: 126 pg/ml (78-222); controls: 112 pg/ml (71-188), P = ns]. In the ALS group, the bulbar-onset patients showed increased CSF tau levels as compared with the spinal-onset cases. These differences might be related to the higher age of the bulbar-onset patients. Further, no correlations were found between CSF tau concentrations and the rate of progression of the disease.

CONCLUSIONS

These results do not support the hypothesis that total CSF tau protein is a reliable biological marker for ALS.

Dysembryoplastic Neuroepithelial Tumor of the Brainstem

Dysembryoplastic neuroepithelial tumor (DNT) is a clinically benign stable lesion, most frequently located in the temporal and frontal lobes, often responsible for epilepsy in young adults. We describe an unusual case of DNT in the brainstem of a 45-year-old woman. Brain MRI showed a multicystic-like lesion localized in the left inferior pons, involving the ipsilateral cerebellar peduncle and partially dislocating the fourth ventricle. The specific pattern of MRI and CT appearance of DNT and its benign course (our patient is clinically stable with unchanged MRI images at two year follow-up) may help differentiate this tumor from other lesions, i.e. ganglioglio-mas and glioneural malformations.

A novel Angiogenin gene mutation in a sporadic patient with amyotrophic lateral sclerosis from southern Italy

Mutations in the Angiogenin gene (ANG) linked to 14q11.2 have been recently discovered to be associated with Amyotrophic Lateral Sclerosis (ALS) in Irish and Scottish populations. In our study we investigated the role of ANG gene in ALS patients from southern Italy. We found a novel mutation in the signal peptide of the ANG gene in a sporadic patient with ALS (SALS). The molecular analysis of the ANG gene also demonstrated an allelic association with the rs11701 single nucleotide polymorphism (SNP) in familial ALS (FALS) but not in SALS patients. Our finding supports the evidence that the ANG gene is involved in ALS.

Carcinoma of the tongue and bulbar-onset amyotrophic lateral sclerosis: unusual differential diagnosis

We present a 72-year-old woman with progressive dysphagia, dysarthria and tongue palsy who was initially diagnosed with bulbar-onset amyotrophic lateral sclerosis (ALS). However, the absence of atrophy or fasciculations in the tongue, as in other voluntary muscles, and the lack of reproducible neurophysiological evidence of denervation, prompted a revision of the diagnostic work-up, which eventually led to the discovery of a carcinoma of the tongue. This case report describes a relatively rare type of oropharyngeal carcinoma that, in its early stage, resembled a bulbar-onset ALS. This differential diagnosis is unusual, and it was fostered by the persistent lack of atrophy of the tongue and the absence of spreading of signs and symptoms of motor neuron degeneration.

Telephone follow-up for patients with amyotrophic lateral sclerosis

The relentless evolution of amyotrophic lateral sclerosis (ALS), a severe neurodegenerative disorder of the upper and lower motoneurons, leads to an increasing level of disability. Most patients, during the course of the disease, become unable to attend the tertiary clinical care center and are thus prevented from enrolling in clinical trials or benefiting from specialized care and management. The main objective of this study was to verify whether the ALS functional rating scale (ALSFRS) could be reliably administered by telephone to patients, when unable to attend the ALS clinic, or to their caregivers. ALSFRS is a validated instrument that assesses the functional status and the disease progression in ALS. We first administered the functional rating scale directly in the clinic to 30 patients, with definite or probable ALS, and to their respective caregivers, and found a very high agreement between the two groups for the total score and the majority of the rating items. Next, we showed, in both patients and caregivers, a high degree of correlation between the total score of the ALSFRS measured by telephone and that reported in the clinic. This indicates that ALSFRS is a reliable instrument for monitoring the disease progression in homebound patients, even when the person contacted by telephone is the caregiver. We also performed a telephone clinic, based on an unstructured interview, with 16 ALS patients at an advanced stage of the disease and unable to attend the ALS clinic. On some occasions, the person interviewed was the caregiver. The symptoms most frequently reported were a worsening of muscle strength, swallowing and breathing problems, constipation, and inability to clear lung secretions. Several patients asked for assistive and adaptive equipment. All patients and caregivers found the telephone clinic very useful and considered it a good complement to the management and care programme.

Noninvasive positive-pressure ventilation in ALS: Predictors of tolerance and survival

OBJECTIVE

To identify factors associated with tolerance and survival after noninvasive positive-pressure ventilation (NIPPV) and to investigate the influence of NIPPV on lung function in patients with ALS.

METHODS

NIPPV was offered to 71 patients with ALS in accordance with currently published guidelines. Effects of NIPPV on lung function and factors influencing tolerance and survival after NIPPV were studied.

RESULTS

Forty-four patients (61.9%; 95% CI: 50.6 to 73.2) tolerated NIPPV (NIPPV use >or=4 h/day) and 27 (38.1%; 95% CI: 26.8 to 49.4) were intolerant (NIPPV use <4 h/day). Patients with mild or moderate bulbar symptoms were more likely to tolerate NIPPV than those with severe impairment (odds ratio = 6.09, 95% CI: 1.18 to 31.52, p = 0.031). After NIPPV introduction, a slower decline in forced vital capacity (FVC) was observed in tolerant vs intolerant patients (p = 0.002). The slope of FVC decline after NIPPV initiation (risk ratio [RR]: 0.78, 95% CI: 0.65 to 0.94, p = 0.01) together with NIPPV tolerance (RR: 0.32, 95% CI: 0.13 to 0.78, p = 0.013) were the only independent predictors of survival in the overall group of patients. In multivariate analysis, body mass index was the most powerful predictor of longer survival after NIPPV in tolerant patients (RR: 0.77, 95% CI: 0.61 to 0.96, p = 0.022).

CONCLUSION

Survival after noninvasive ventilation was independently related to ventilatory use (>or=4 h/day) and to the modifications of forced vital capacity decline after treatment initiation. The severity of bulbar impairment and the nutritional status of the ALS patients at the introduction of ventilation may predict tolerance and survival.

A novel mutation (Thr116Ile) in the presenilin 1 gene in a patient with early-onset Alzheimer's disease

We report a novel presenilin 1 (PSN1) mutation (Thr116Ile) in a woman with early onset Alzheimer's disease (AD). This mutation was not found in 100 healthy controls, indicating that this is not a common polymorphism. The patient presented with forgetfulness at age 45, followed over the next 3 years by a worsening of the memory loss and frequent episodes of confusion and spatial disorientation. Neuroimaging studies were consistent with AD. The analysis of the family's pedigree showed that the proband was apparently the only member affected. Because the early death of several close relatives (i.e. the mother and the grandmother) and the demonstration that the father is not a mutation carrier, it is suggested that either a de novo mutation or a censor effect might have occurred. Our finding supports the indication that PSN1 mutations should be searched for in early-onset AD, particularly when a censor effect precludes a precise genetic analysis.

Long-term interferon-β treatment for multiple sclerosis

The aim of our study was to analyze the dropout rate in patients with relapsing-remitting multiple sclerosis (RRMS) under long-term treatment with the three commercially available interferon beta (IFNbeta) preparations. According to the drug taken, we divided 122 RRMS patients into 4 groups: Betaferon group, 56 patients taking INFbeta-1b (24 MIU weekly, subcutaneous injections); Avonex group, 38 patients taking IFNbeta-1a (6 MIU weekly, intramuscularly); Rebif group, 18 patients taking INFbeta-1b (18 MIU subcutaneously). Ten patients who shifted from Betaferon to Avonex were included in a fourth group. Dropouts were registered every trimester with the related cause. Data were evaluated using Kaplan-Meier survival analysis and log-rank test. During the observation period of five years, 48 patients (39.9%) dropped out: 48% of the patients in Betaferon group withdrew at a median of 758 days, 26% of the Avonex group at 356 days; 38% of the Rebif group at 421 days, and 40% of those who shifted from Betaferon to Avonex at 259 days. The differences between groups were not significant on survival analysis. Patients receiving higher dose treatment (Betaferon and Rebif groups) dropped out mainly for clinical adverse events; conversely, patients receiving lower dose therapy (Avonex group) dropped out most often for inefficacy. Patients who shifted to a lower dose treatment (fourth group) had a dropout rate similar to that of the initial treatment. Our data showed that one-third of the patients stopped the therapy, mostly for adverse events and then for inefficacy, while the remaining two-thirds were still on treatment without problems up to 5 years of follow-up. Compliance seems related to the dose of the drug, but further analysis is needed to confirm our data.

Bulbar-onset amyotrophic lateral sclerosis in a patient with Chiari I malformation

We report on a patient with bulbar-onset, clinically defined, sporadic amyotrophic lateral sclerosis (ALS) who also showed a Chiari I malformation. This malformation, otherwise asymptomatic, was detected during the diagnostic work-up for ALS. To our knowledge this is the first report of an association between these two relatively uncommon disorders. Since our patient worked for many years as a bus-driver and because the ALS symptoms began in the brainstem region, we suggest that his hindbrain anomaly, along with the mechanical stress on the spine and cranio-vertebral junction due to the daily driving, might have played a role in the region-specific onset of ALS.

Expression and subcellular localization of two isoforms of the survival motor neuron protein in different cell types

The survival motor neuron (SMN) gene is deleted or mutated in over 98% of spinal muscular atrophy patients who show specific motoneuron loss. By performing transfection experiments with rat smn cDNA, we show that two isoforms of SMN with Mr of 32 kDa and 35 kDa are produced by the same cDNA. In cultured motoneurons, both forms colocalize in coiled bodies and not in GEMS bodies as shown for HeLa cells. Subcellular fractionation of cells acutely dissociated from rat embryonic ventral spinal cord shows that the two SMN isoforms have a different subcellular localization, namely, that the 32 kDa isoform is enriched in the cytosol, whereas the 35 kDa isoform is segregating in the microsomal fraction. We show that the 35 kDa isoform of SMN is part of an insoluble complex but is absent from the cytoplasmic membranes and from the mitochondria. Immunostaining studies show that neither SMN isoform colocalizes with Bcl-2, the mitochondrial antiapoptotic protein suggested to bind to SMN in HeLa cells. Our results show that the isoforms of SMN protein have different subcellular localization and may therefore play independent biological roles. Moreover, the absence of colocalization of SMN with Bcl-2 in motoneurons suggests that some of the interactors of SMN may vary depending on the cell type, and this underscores the importance of identifying motoneuron-specific SMN interactors.

Differential effect of beta-N-oxalylamino-L-alanine, the Lathyrus sativus neurotoxin, and (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate on the excitatory amino acid and taurine levels in the brain of freely moving rats

We studied the effect of beta-oxalylamino-L-alanine, a glutamate analog present in Lathyrus sativus seeds and implicated in the etiopathogenesis of neurolathyrism, and (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate on the extracellular levels of aspartate, glutamate and taurine in the primary motor cortex of freely moving rats. We found that while both neurotoxins increase the level of aspartate and glutamate, only (+/-)-alpha(-amino-3-hydroxy-5-methylisoxazole-4-propionate is able to modulate the level of taurine. GYKI-52466, a non-competitive non-NMDA antagonist, inhibited beta-oxalylamino-L-alanine-induced increase of aspartate, but not that of glutamate. Conversely, this antagonist proved to be very efficient in blocking the stimulating effect of (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate on all three amino acids. We suggest that beta-oxalylamino-L-alanine increases the level of glutamate in vivo by a mechanism not connected to its effect on the non-NMDA receptors, which might involve the inhibition of glutamate transport. This would allow the excitatory neurotransmitter to reach a concentration sufficient to stimulate the non-NMDA receptors, which in their turn mediate the specific release of aspartate. Although the role of aspartate as a neurotransmitter is still under discussion, it might indeed amplify the excitotoxic cascade through its action on NMDA receptors. We speculate that this sequence of events might represent an important step in the molecular cascade leading to the appearance of the selective motoneuron degeneration in neurolathyrism.

Subcellular distribution of survival motor neuron (SMN) protein: possible involvement in nucleocytoplasmic and dendritic transport

Spinal muscular atrophy (SMA) is among the most common recessive autosomal diseases and is characterized by the loss of spinal motor neurons. A gene termed 'Survival of Motor Neurons' (SMN) has been identified as the SMA-determining gene. Recent work indicates the involvement of the SMN protein and its associated protein SIP1 in spliceosomal snRNP biogenesis. However, the function of SMN remains unknown. Here, we have studied the subcellular localization of SMN in the rat spinal cord and more generally in the central nervous system (CNS), by light fluorescence and electron microscopy. SMN immunoreactivity (IR) was found in the different regions of the spinal cord but also in various regions of the CNS such as the brainstem, cerebellum, thalamus, cortex and hippocampus. In most neurons, we observed a speckled labelling of the cytoplasm and a discontinuous staining of the nuclear envelope. For some neurons (e.g. brainstem nuclei, dentate gyrus, cortex: layer V) and, in particular in motoneurons, SMN-IR was also present as prominent nuclear dot-like-structures. In these nuclear dots, SMN colocalized with SIP1 and with fibrillarin, a marker of coiled bodies. Ultrastructural studies in the anterior horn of the spinal cord confirmed the presence of SMN in the coiled bodies and also revealed the protein at the external side of nuclear pores complexes, in association with polyribosomes, and in dendrites, associated with microtubules. These localizations suggest that, in addition to its involvement in the spliceosome biogenesis, the SMN protein could also play a part in nucleocytoplasmic and dendritic transport.

Survival motor neuron (SMN) protein in rat is expressed as different molecular forms and is developmentally regulated

Spinal muscular atrophy (SMA) is an autosomal recessive disease characterized by a progressive degeneration of motoneurons in spinal cord and brainstem. The telomeric copy of a duplicated gene termed survival motor neuron (smn), which maps to chromosome 5q13, has been found to be deleted in most patients. The encoded gene product is a novel protein which recently has been shown to accumulate in specific nuclear organelles (gemini of coiled bodies, GEMS), and to play a part in the formation of the spliceosome complex. We have cloned and sequenced the rat smn cDNA. Antibodies generated against an N-terminus peptide recognized a main protein of 32 kDa in immunoblots of rat embryonic tissue extracts. Minor bands of 35 kDa, 45 kDa and, in perinatal muscle, of 24 kDa were also specifically detected, indicating that SMN is expressed as different molecular forms. Subcellular fractionation indicated that the 32 kDa form is mainly soluble, while the 35 kDa and 45 kDa products segregate to the microsomal-mitochondrial fraction. SMN protein is highly regulated during development: expression is high in embryonic tissues (central nervous system, muscle, lung and liver), and then progressively decreases to very low levels in most tissues of the adult. The demonstration of different molecular forms of SMN along with its developmental regulation may help to understand the contribution of this protein in the appearance of SMA phenotype.

The differential in vitro stimulation of 3',5'-cyclic nucleotide phosphodiesterase by calcium binding proteins

A heterogeneous class of proteins exhibit within their sequence a particular structure, named EF-hand, able to bind calcium with high affinity. These calcium binding proteins have been described in most cells and tissues and are suggested to work as calcium buffers, thereby participating in the regulation of calcium-dependent cellular activity. Recent circumstantial evidences suggest that calcium binding proteins may serve other functions as well, possibly as enzyme modulators. Since 3',5'-cyclic nucleotide phosphodiesterase is a well-known calmodulin-modulated enzyme, in this work we studied the effect in vitro of different purified calcium binding proteins on the activity of this enzyme. Among the proteins tested, calmodulin and recombinant rat brain parvalbumin could stimulate the 3',5'-cyclic nucleotide phosphodiesterase activity in vitro, whereas rabbit muscle parvalbumin, rat renal and brain calbindin D28K, and bovine brain S-100B were ineffective. Immunoprecipitation with the specific antiserum completely abolished either calmodulin or recombinant brain parvalbumin activation of 3',5'-cyclic nucleotide phosphodiesterase. Moreover, while the presence of calcium in the incubation mixture was critical in the calmodulin-mediated stimulation of the enzyme, it did not modify the effect of the recombinant brain parvalbumin. We suggest that, in addition to calmodulin, parvalbumin may be a regulator of 3',5'-cyclic nucleotide phosphodiesterase, and possibly of other yet to be identified enzymes in certain tissues.

Increased CSF glutamate following injection of ALS immunoglobulins

To reconcile the autoimmune and excitotoxic hypotheses regarding the etiology of amyotrophic lateral sclerosis (ALS), we injected rats intraperitoneally with ALS immunoglobulins and monitored CSF glutamate, aspartate, glutamine, and glutathione. CSF glutamate was significantly increased at 24 and 72 hours compared with both basal levels and disease control injected rats. CSF aspartate was increased at 72 hours. Glutamine and glutathione were unchanged. These data suggest that ALS immunoglobulins may enhance CSF glutamate and aspartate levels and contribute to motoneuron injury.

Dietary consumption of Lathyrus sativus seeds induces behavioral changes in the rat

Neurolathyrism is a degenerative disorder due to an excessive consumption of Lathyrus sativus (LS) seeds, which contain the neurotoxic amino acid beta-N-oxalylamino-L-alanine. In this study, a population of Wistar rats was fed a diet with LS seeds up to 8 months. Two control groups were chosen, one receiving standard food and the other Cicer arietinum seeds (a nontoxic legume). At the end of the dietary period, the groups previously fed the seeds were switched to standard food for 1 month (wash-out). All animals were submitted to a neurological examination and observed in an open-field situation before, during the diet (at 4 and 8 months), and finally after wash-out. Neither LS-fed rats nor controls ever showed neurological deficits. By contrast, in an open-field the activity was significantly increased in the LS-eating rats at both the 4th and 8th month. The effect was indeed reversible, since it disappeared after the wash-out. It is suggested that the enhanced open-field activity seen in the LS group might indicate a reversible excitable status. However, there is no evidence at present that the behavioral changes described represent a marker of neurodegeneration in this animal species.

Calbindin D28K forms a Ca(2+)-dissociable complex with mellitin in vitro

Calbindin D28K (CB), a cytosolic calcium binding protein (CBP), forms a macromolecular complex with the polypeptide mellitin (ME) the absence of calcium, which can be reversibly dissociated by the addition of Ca2+. The molar ratio of CB:ME constituted in this complex is 1:4, suggesting that CB interacts with the tetrameric form of ME. Like free tetrameric ME, the CB:ME complex does not migrate into 15% non-denaturing polyacrylamide electrophoretic gels, although both constituents migrate normally after irreversible complex denaturation by heating in sodium dodecyl sulphate (SDS). The interaction of these two proteins can be distinguished from the association of calmodulin (CM) with ME, which forms a reversibly dissociable, equimolar complex in the presence of Ca2+ and a stable non-migrating complex (molar ratio = 1:12) in its absence. Thus, CB and CM appear to bind ME under different Ca2+ regulatory control, suggesting possible roles for CB as a Ca(2+)-dependent regulatory binding protein.

Apoptosis induced by beta-N-oxalylamino-L-alanine on a motoneuron hybrid cell line

It has been suggested that beta-N-oxalylamino-L-alanine, a non-protein amino acid present in the Lathyrus Sativus seeds, may play a role in the etiopathogenesis of neurolathyrism, a toxic form of motor neuron disease clinically characterized by a severe spastic paraparesis. In order to investigate the mechanisms of beta-N-oxalylamino-L-alanine-mediated cell death, we studied the effect of this neurotoxin as well as other excitatory amino acids agonists on the growth and survival of motoneuron hybrid ventral spinal cord 4.1 cells. beta-N-oxalylamino-L-alanine was toxic to ventral spinal cord 4.1 cells in a concentration-dependent fashion (0.5-10 mM). Among the excitatory amino acids tested, only glutamate (1-10 mM), quisqualate (1 mM) and, with less extent, beta-N-methylamino-L-alanine (10 mM) induced a significant reduction of cell survival. The effect of Lathyrus Sativus neurotoxin was a slow process, becoming apparent only after 24-48 h of incubation. Interestingly, a mathematical analysis applied to the time course and dose curve of beta-N-oxalylamino-L-alanine toxicity suggested that even for very low concentrations of the amino acid it is theoretically possible to predict a time-dependent effect. The cell death was not blocked by antagonists of N-methyl-D-aspartate or non-N-methyl-D-aspartate receptors; aurintricarboxylic acid and alpha-tocopherol gave a partial protection; cysteine (1 mM) prevented the toxic effect of both Lathyrus Sativus neurotoxin and glutamate as well as quisqualate. Morphologically, in the presence of either beta-N-oxalylamino-L-alanine, glutamate or quisqualate, ventral spinal cord 4.1 cells showed apoptotic features also confirmed by ISEL technique and agarose gel electrophoresis of genomic DNA. Thus, our results suggest that in ventral spinal cord 4.1 motoneuron hybrid cells, in the absence of functional synaptic excitatory amino acid receptors, beta-N-oxalylamino-L-alanine induces cell degeneration through an apoptotic mechanism, possibly mediated by a block of cystine/glutamate Xc antiporter.

The role of calcium-binding proteins in selective motoneuron vulnerability in amyotrophic lateral sclerosis

The factors contributing to selective motoneuron loss in amyotrophic lateral sclerosis (ALS) remain undefined. To investigate whether calcium-binding proteins contribute to selective motoneuron vulnerability in ALS, we compared calbindin-D28K and parvalbumin immunoreactivity in motoneuron populations in human ALS, and in a ventral spinal cord hybrid cell line selectively vulnerable to the cytotoxic effects of ALS IgG. In human autopsy specimens, immunoreactive calbindin-D28k and parvalbumin were absent in motoneuron populations lost early in ALS (i.e., cortical and spinal motoneurons, lower cranial nerve motoneurons), while motoneurons damaged late or infrequently in the disease (i.e., Onuf's nucleus motoneurons, oculomotor, trochlear, and abducens nerve neurons) expressed markedly higher levels of immunoreactive calbindin-D28K and/or parvalbumin. Motoneuron-neuroblastoma VSC 4.1 hybrid cells lost immunoreactive calbindin-D28k and parvalbumin following dibutyryl-cyclic AMP-induced differentiation and were killed by IgG from ALS patients. Undifferentiated calbindin/parvalbumin-reactive VSC 4.1 cells were not killed, nor were other cell lines expressing high levels of calbindin-D28K and parvalbumin immunoreactivity (substantia nigra-neuroblastoma hybrid cells and N18TG2 neuroblastoma parent cells). These studies suggest that decreased calbindin-D28K and parvalbumin immunoreactivity may help explain the selective vulnerability of motoneurons in ALS.

CDP-choline in the treatment of chronic cerebrovasculopathies

Ninety-two patients affected by chronic cerebrovasculopathy were treated with cytidine diphosphate choline (CDP-choline) 1000 mg/day i.m. or with placebo, in a double-blind study. Two cycles of therapy of 4 weeks each were performed, with an interval of 1 week. There were 46 patients in each group with chronic cerebrovascular diseases, and the two groups were comparable as far as mental deterioration was concerned. The following psychometric tests were administered: Toulouse-Piéron (attention to non-verbal stimuli), Randt Memory test (memory), Sandoz Clinical Assessment of Geriatrics (SCAG, measurement of the behavioral and emotional control). The comparison between the two groups revealed significant improvements in the CDP-choline group compared with the placebo group in some of the attention capabilities (decrease in the number of wrong answers at the Toulouse-Piéron test), of the mnemonic capabilities ('General Information' subtest of Randt Memory test) and behavioral capabilities (SCAG 'affective disturbances' score). No side-effects were detected in the CDP-choline group.

Effect of beta-N-oxalylamino-L-alanine on cerebellar cGMP level in vivo

Beta-N-oxalylamino-L-alanine (BOAA), a non-protein amino acid present in the seeds of Lathyrus Sativus (LS), is one of several neuroactive glutamate analogs reported to stimulate excitatory receptors and, in high concentrations, cause neuronal degeneration. In the present study, the in vivo acute effects of synthetic BOAA and LS seed extract were investigated on rat cerebellar cyclic GMP following intraperitoneal (10-100 mg/kg) or oral (100 mg/kg) administration of subconvulsive doses of toxin. Furthermore, the BOAA content in LS seeds and in the cerebellum of injected rats was determined by high performance liquid chromatograph analysis. A dose- and time-dependent increase of cerebellar cyclic guanosine monophosphate (cGMP) level was observed after intraperitoneal administration of synthetic BOAA or LS extract. The neurotoxin evoked a maximum stimulation 90 min after injection within the dose range of 50-75 mg/kg, elevating cGMP from basal levels of 5.3 +/- 0.5 pmol/mg protein to 15 +/- 1.3 pmol/mg protein. Similarly, the oral intake of LS-extracted neurotoxin resulted in the elevation of cGMP content. Kynurenic acid (300 mg/kg i.p.), a non specific excitatory amino acid antagonist, was effective in blocking LS BOAA-elicited cGMP enhancement. The data suggest that in the cerebellum acute administration of low concentrations of BOAA exert in vivo activation of glutamate receptors involved in the regulation of cGMP level.

New insights on the pathogenesis of neurodegenerative disorders

In the last few years, an increasing amount of studies have been dedicated to the etiopathogenesis of age-related neurodegenerative disorders, such as Parkinson's disease, amyotrophic lateral sclerosis and Alzheimer's disease. The discovery of synthetic, as well as natural molecules, able to reproduce in the animals biochemical and morphological alterations of neurodegenerative disorders, has provided a major impetus to the "environmental" hypothesis of neurodegeneration. In this review, following a brief description of the ability of the nervous system to counteract the degenerative process, the main neurotoxic-based animal models for neurodegeneration are examined. These might give us interesting clues for understanding the pathogenetic mechanism(s) of neurodegenerative process.

Binding of flunitrazepam to differentiating neurons cultured in a chemically defined, hormone-supplemented medium

[3H]Flunitrazepam (FNZ) binding to cortical neurons from fetal rat brain was investigated in vitro. The use of a synthetic medium specific for neurons made it possible to plot a developmental curve of 3H-FNZ binding in an almost pure neuronal culture. Detectable specific binding was present in vitro at time 0 (that is, the 16th gestational day). A progressive increase of binding, due to an increment in the number of recognition sites, was observed on the subsequent days. The affinity of the specific binding sites to 3H-FNZ was enhanced by the addition of exogenous GABA, whereas the density was not affected.

Lateral differences in GABA binding sites in rat brain

An asymmetric distribution of GABA binding sites was found in the cerebral cortex, hippocampus, cerebellar hemispheres, striatum, and thalamus. Higher levels of [3H]GABA binding were observed in the left-side of most brain areas and in a greater percentage of adult rats, but the opposite asymmetry was found in the thalamus. A similar left-right difference in cerebral hemispheres was also found in five day-old rats, suggesting the genetic predetermination of asymmetry.

Interaction between uridine and GABA-mediated inhibitory transmission: studies in vivo and in vitro

Na+-independent [3H]gamma-aminobutyric acid (GABA) binding to membrane preparations from frontal cortex, hippocampus, and thalamus is competitively inhibited by the in vitro addition of a naturally occurring pyrimidinic compound, uridine. Moreover, the intraperitoneal injection of uridine produces a dose-related decrease in the cerebellar content of cyclic GMP and antagonizes its increase elicited by bicuculline. The pyrimidinic compound also shows an antagonism toward bicuculline-induced seizures. The relationship between the anti-convulsant actions of uridine and GABA-mediated inhibitory neurotransmission is discussed in terms of an activation of GABA receptor function by the naturally occurring pyrimidinic compound.