Recovery of motor function after spinal-cord injury--a randomized, placebo-controlled trial with GM-1 ganglioside

BACKGROUND

Spinal-cord injury is devastating; until recently, there was no medical treatment to improve recovery of the initial neurologic deficit. Studies in animals have shown that monosialotetrahexosylganglioside (GM-1) ganglioside enhances the functional recovery of damaged neurons.

METHODS

A prospective, randomized, placebo-controlled, double-blind trial of GM-1 ganglioside was conducted in patients with spinal-cord injuries. Of 37 patients entered into the study, 34 (23 with cervical injuries and 11 with thoracic injuries) completed the test-drug protocol (100 mg of GM-1 sodium salt or placebo intravenously per day for 18 to 32 doses, with the first dose taken within 72 hours of the injury) and a one-year follow-up period. Neurologic recovery was assessed with the Frankel scale (comprising five categories) and the American Spinal Injury Association (ASIA) motor score (a scale of scores from 0 to 100, derived from strength tests of 20 specific muscles, each scored from 0 to 5).

RESULTS

There was a significant difference between groups in the distribution of improvement of Frankel grades from base line to the one-year follow-up (improvement of 0, 1, 2, and 3 grades in 13, 4, 1, and 0 patients, respectively, in the placebo group and 8, 1, 6, and 1 patients, respectively, in the GM-1 group; P = 0.034 by the Cochran-Mantel-Haenszel chi-square test). The GM-1-treated patients also had a significantly greater mean improvement in ASIA motor score from base line to the one-year follow-up than the placebo-treated patients (36.9 vs. 21.6 points; P = 0.047 by analysis of covariance with the base-line ASIA motor score as the covariate). An analysis of individual muscle recoveries revealed that the increased recovery in the GM-1 group was attributable to initially paralyzed muscles that regained useful motor strength rather than to strengthening of paretic muscles.

CONCLUSIONS

This small study provides evidence that GM-1 enhances the recovery of neurologic function after one year. A larger study must be conducted, however, before GM-1 is considered efficacious and safe in treating spinal-cord injury.

The Sygen multicenter acute spinal cord injury study

STUDY DESIGN

Randomized, double-blind, sequential, multicenter clinical trial of two doses of Sygen versus placebo.

OBJECTIVES

To determine efficacy and safety of Sygen in acute spinal cord injury.

SUMMARY OF BACKGROUND DATA

An earlier, single-center trial in 28 patients showed an improvement (50.0% vs. 7.1%, P = 0.034) in marked recovery with Sygen.

METHODS

Standard clinical trial techniques.

RESULTS

The prospectively planned analysis at the prespecified endpoint time for all patients was negative. There was a significant effect in all patients in the primary outcome variable (the percentage of marked recovery) at week 8, the end of the dosing period. There was a significant effect in all patients in the time at which marked recovery is first achieved. Restricted to severity Group B, which has small sample size, the primary efficacy analysis showed a trend but did not reach significance. There is a large, consistent and, at some time points, significant effect in the primary outcome variable in the nonoperated patients through week 26. The American Spinal Injury Association motor, light touch, and pinprick scores showed a consistent trend in favor of Sygen, as also did bowel function, bladder function, sacral sensation, and anal contraction. The less severely injured patients appeared to have a greater beneficial drug effect. Evidence against an effect of Sygen was minimal and scattered.

CONCLUSIONS

Although not proven in the primary efficacy analysis of this trial, Sygen appears to be beneficial in patients with severe spinal cord injury.

Spinal cord injury in the rat

Only limited therapeutic measures are currently available for the treatment of spinal cord injury. This review describes the pathologic mechanisms of trauma-induced spinal cord injury in rats, which will contribute to new understanding of the pathologic process leading to spinal cord injury and to further development of new therapeutic strategies. Spinal cord injury induced by trauma is a consequence of an initial physical insult and a subsequent progressive injury process that involves various pathochemical events leading to tissue destruction; the latter process should therefore be a target of pharmacological treatment. Recently, activated neutrophils have been shown to be implicated in the latter process of the spinal cord injury in rats. Activated neutrophils damage the endothelial cells by releasing inflammatory mediators such as neutrophil elastase and oxygen free radicals. Adhesion of activated neutrophils to the endothelial cell could also play a role in endothelial cell injury. This endothelial cell injury could in turn induce microcirculatory disturbances leading to spinal cord ischemia. We have found that some therapeutic agents that inhibit neutrophil activation alleviate the motor disturbances observed in the rat model of spinal cord injury. Methylprednisolone (MPS) and GM1 ganglioside, which are the only two pharmacological agents currently clinically available for treatment of acute spinal cord injury, do not inhibit neutrophil activation in this rat model. Taken together, these observations raise a possibility that other pharmacological agents that inhibit neutrophil activation used in conjunction with MPS or GM1 ganglioside may have a synergistic effect in the treatment of traumatic spinal cord injury in humans.

Recovery from experimental parkinsonism in primates with GM1 ganglioside treatment

A parkinsonian syndrome can be produced in nonhuman primates by administration of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Parkinsonian-like symptoms induced acutely by MPTP were ameliorated after treatment with GM1 ganglioside, a substance shown to have neurotrophic effects on the damaged dopamine system in rodents. Treatment with GM1 ganglioside also increased striatal dopamine and metabolite levels and enhanced the dopaminergic innervation of the striatum as demonstrated by tyrosine hydroxylase immunohistochemistry. These results suggest that GM1 ganglioside may hold promise as a therapeutic agent for the treatment of Parkinson's disease.

Deficiency of ganglioside GM1 correlates with Parkinson's disease in mice and humans

Several studies have successfully employed GM1 ganglioside to treat animal models of Parkinson's disease (PD), suggesting involvement of this ganglioside in PD etiology. We recently demonstrated that genetically engineered mice (B4galnt1(-/-) ) devoid of GM1 acquire characteristic symptoms of this disorder, including motor impairment, depletion of striatal dopamine, selective loss of tyrosine hydroxylase-expressing neurons, and aggregation of α-synuclein. The present study demonstrates similar symptoms in heterozygous mice (HTs) that express only partial GM1 deficiency. Symptoms were alleviated by administration of L-dopa or LIGA-20, a membrane-permeable analog of GM1 that penetrates the blood-brain barrier and accesses intracellular compartments. Immunohistochemical analysis of paraffin sections from PD patients revealed significant GM1 deficiency in nigral dopaminergic neurons compared with age-matched controls. This was comparable to the GM1 deficiency of HT mice and suggests that GM1 deficiency may be a contributing factor to idiopathic PD. We propose that HT mice with partial GM1 deficiency constitute an especially useful model for PD, reflecting the actual pathophysiology of this disorder. The results point to membrane-permeable analogs of GM1 as holding promise as a form of GM1 replacement therapy.

GM1 ganglioside treatment facilitates behavioral recovery from bilateral brain damage

Adult rats with bilateral lesions of the caudate nucleus were treated with GM1 ganglioside. Although animals injected with a control solution were severely impaired in their ability to learn a complex spatial task, those treated with ganglioside were able to learn spatial reversals.

A randomized, controlled, delayed start trial of GM1 ganglioside in treated Parkinson's disease patients

The present single center, double-blind, delayed start study was conducted to examine possible symptomatic and disease-modifying effects of GM1 ganglioside in Parkinson's disease (PD). Seventy-seven subjects with PD were randomly assigned to receive GM1 for 120 weeks (early-start group) or placebo for 24 weeks followed by GM1 for 96 weeks (delayed-start group). Washout evaluations occurred at 1 and 2 years after the end of treatment. Seventeen additional subjects who received standard-of-care were followed for comparative information about disease progression. Primary outcome was change from baseline Unified Parkinson's Disease Rating Scale (UPDRS) motor scores. At week 24, the early-start group had significant improvement in UPDRS motor scores vs. a significant worsening of scores in the delayed-start group. The early-start group also showed a sustained benefit vs. the delayed-start group at week 72 and at week 120. Both groups had significant symptom worsening during washout. This study provides evidence that GM1 use for 24 weeks was superior to placebo for improving motor symptoms and that extended GM1 use (up to 120 weeks) resulted in a lower than expected rate of symptom progression. The data from this small study suggest that GM1 may have symptomatic and potentially disease modifying effects on PD.

Retrograde changes in the nucleus basalis of the rat, caused by cortical damage, are prevented by exogenous ganglioside GM1

In rats with extensive unilateral cortical damage, retrograde effects upon the cholinergic cells of the basal nucleus were observed. Cells of the basal nucleus stained immunocytochemically for choline acetyltransferase were shrunken and choline acetyltransferase enzymatic activity in that region was reduced. Both these effects could be prevented by the administration of the ganglioside GM1.

Measurements and recovery patterns in a multicenter study of acute spinal cord injury

STUDY DESIGN

Post hoc, secondary analysis of data from 1992 to 1998 in the trial of Sygen in acute spinal cord injury.

OBJECTIVES

Quasi-epidemiologic understanding of measurement tools and of recovery patterns. No drug efficacy results.

SUMMARY OF BACKGROUND DATA

Many authors have studied individual scales for measuring the severity of spinal cord injury.

METHODS

Emphasis on descriptive, rather than inferential, statistics: consistent with secondary analysis.

RESULTS

Of the 760 patients, 43 died within 365 days. The rate was higher for complete injuries (7.1% vs. 3.2%, P = 0.017). Marked recovery at 26 weeks was more frequent in those with better baseline American Spinal Injury Association (ASIA) Impairment Scale (AIS) scores, but was not different for methylprednisolone within versus after 3 hours. Light touch scores improved at each visit, more so in those with higher scores at baseline. Bladder control similarly improved. Motor and sensory scores exhibited departures from assumptions underlying normal-theory statistical techniques: t test and analysis of variance. Furthermore, they were mixtures of differing distributions from different study strata, so that overall conclusions depend on the mixture of patients seen.

CONCLUSIONS

The prognosis of these patients with spinal cord injury seen at 28 centers in North America during the mid-1990s appears better than was often assumed earlier. The general patterns are similar across different measurement scales, although there are intriguing differences. The patterns in different strata are different in specifics, and complete injuries do less well. Pooling data from different strata may result in probability distributions that depart from normal-theory assumptions and give misleading results depending on recruitment patterns.

Alzheimer disease - effect of continuous intracerebroventricular treatment with GM1 ganglioside and a systematic activation programme

Five patients with the early-onset form of Alzheimer disease (AD) received GM1 ganglioside by continuous injection into the frontal horns of the lateral ventricles for a period of 12 months. The optimal GM1 dose varied between 20 and 30 mg/24 h. The patients were trained twice a week for 4-5 h with an individually designed cognitive programme, which included the use of a word processor. Neurological, neuropsychological, psychiatric and neurochemical examinations were performed a week before surgery and on days 30, 90, 180, 270 and 365 after surgery. The cerebrospinal fluid levels of the monoamine metabolites homovanillic acid and 5-hydroxyindoleacetic acid and the neuropeptide somatostatin increased. The regional cerebral blood flow showed a tendency to increase. The progression of deterioration was stopped, and motor performance and neuropsychological assessments improved. The patients became more active and felt safer in relation to other people and performing various activities. They had improved reading comprehension and a better feeling for language. They were able to write reports and short letters on a word processor. When interviewed at the end of the study, all 5 patients stated that they felt better, and their relatives reported that they had regained integrity and their joie de vivre.

GM1 ganglioside therapy in acute ischemic stroke. Italian Acute Stroke Study--Hemodilution + Drug

Eleven of 31 clinical centers participating in the Italian Acute Stroke Study--Hemodilution carried out a preliminary study on the effectiveness of ganglioside GM1 in acute stroke; 502 patients were randomized to GM1 (GM1, n = 121), GM1 plus hemodilution (GM1 + H, n = 128), placebo (P, n = 130), or placebo plus hemodilution (P + H, n = 123) groups less than or equal to 12 hours after onset of a hemispheric cerebral infarct. The patients were treated for 15 days and were evaluated on Days 21 and 120 after the onset of stroke. Intention-to-treat analysis failed to show any differences in neurologic deficit, mortality, or neurologic disability among the groups. Efficacy analysis showed a significantly higher degree of neurologic improvement in GM1 group patients compared with patients in the P group during the first 15 days. GM1-treated patients (GM1 and GM1 + H groups) showed a significantly higher degree of neurologic improvement during the first 10 days compared with the placebo-treated patients (P and P + H groups). These differences were no longer statistically significant at Day 120. Our results provide a rationale for the planning of a larger, multicenter trial of GM1 ganglioside in acute stroke.

GM1 Ganglioside Is A Key Factor in Maintaining the Mammalian Neuronal Functions Avoiding Neurodegeneration

Many species of ganglioside GM1, differing for the sialic acid and ceramide content, have been characterized and their physico-chemical properties have been studied in detail since 1963. Scientists were immediately attracted to the GM1 molecule and have carried on an ever-increasing number of studies to understand its binding properties and its neurotrophic and neuroprotective role. GM1 displays a well balanced amphiphilic behavior that allows to establish strong both hydrophobic and hydrophilic interactions. The peculiar structure of GM1 reduces the fluidity of the plasma membrane which implies a retention and enrichment of the ganglioside in specific membrane domains called lipid rafts. The dynamism of the GM1 oligosaccharide head allows it to assume different conformations and, in this way, to interact through hydrogen or ionic bonds with a wide range of membrane receptors as well as with extracellular ligands. After more than 60 years of studies, it is a milestone that GM1 is one of the main actors in determining the neuronal functions that allows humans to have an intellectual life. The progressive reduction of its biosynthesis along the lifespan is being considered as one of the causes underlying neuronal loss in aged people and severe neuronal decline in neurodegenerative diseases. In this review, we report on the main knowledge on ganglioside GM1, with an emphasis on the recent discoveries about its bioactive component.

Vaccination of patients with small-cell lung cancer with synthetic fucosyl GM-1 conjugated to keyhole limpet hemocyanin

PURPOSE

Immunotherapy directed toward cell surface antigens may provide a novel approach to the eradication of chemoresistant micrometastatic disease in patients with small-cell lung cancer (SCLC). Studies in SCLC cell lines and human tissues suggest that the ganglioside fucosyl GM1 is an abundant yet specific target. A prior clinical study demonstrated the potent immunogenicity of fucosyl GM-1 derived from bovine thyroid gland, conjugated to keyhole limpet hemocyanin (KLH) and administered with QS-21 adjuvant.

EXPERIMENTAL DESIGN

We tested the immunogenicity of three different doses of a synthetic version of fucosyl-GM1 in patients with SCLC after a major response to initial therapy. The primary end point was to establish the lowest effective dose capable of inducing antibody production.

RESULTS

Five of six patients at the 30-microg dose and three of five patients at the 10-microg dose mounted IgM responses of 1:80 or greater. These antibodies were confirmed by flow cytometry in seven of eight cases. None of the patients at the 3-microg dose had titers above 1:80. One patient at the 30-microg dose had an IgG response with a titer of 1:80. The sera from six of the eight responders induced potent complement-mediated cytotoxicity of tumor cells.

CONCLUSIONS

Vaccination with the synthetic fucosyl GM1-KLH conjugate induces an IgM antibody response against fucosyl GM1 and tumor cells expressing fucosyl GM1, comparable with the response induced by the bovine derivative. We plan to combine synthetic fucosyl GM1 vaccine at a dose of 30 microg with vaccines against three other antigens-GM2, Globo H, and polysialic acid-to test in patients with SCLC after initial chemotherapy.

Gangliosides (GM1 and AGF2) reduce mortality due to ischemia: protection of membrane function

As evidenced by their ability to reduce cerebral edema, exogenous ganglioside administration exerts acute effects on CNS injury processes. We report here that ganglioside (GM1 or AGF2) treatment results in a 52% decrease in mortality 48 hours after the induction of ischemia in gerbils by permanent unilateral ligation of the common carotid artery. By comparing the occluded vs. nonoccluded sides of the brain (cortex and hippocampus) we found a significant loss of membrane Na, K-ATPase activity due to ischemia in control animals, but no such differences were found between the hemispheres of ganglioside-treated gerbils. We hypothesize that gangliosides may be "protecting" membrane function as indicated by these ATPase analyses, reducing local CNS damage at the time of injury (i.e., reduced cell loss, fiber degeneration, membrane failure). By acutely limiting the extent of CNS tissue damage, conditions may be optimized for any subsequent CNS regrowth and functional recovery.

Gangliosides minimize behavioral deficits and enhance structural repair after brain injury

Injections of GM1-gangliosides (30 mg/kg, i.p.) in adult rats were shown to reduce behavioral deficits after brain lesions. This was observed (1) after bilateral electrolytic lesions of the caudate nucleus in a learning task involving negative reinforcement; (2) following aspiration lesions of the mediofrontal cortex in a learning task involving positive reinforcement; and (3) when rotational behavior was assessed after amphetamine or apomorphine injections in animals with partial hemitransections of the nigro-striato-nigral fibers. A detailed anatomical analysis of the latter study, using a retrograde tract-tracing dye wheat germ agglutinin-horseradish peroxidase (WGA-HRP), provided evidence for ganglioside-stimulated, neuronal reorganization of connections to the caudate nucleus. Our findings support the notion that gangliosides reduce behavioral deficits following brain injury by preventing secondary neuronal degeneration and/or enhancing structural reorganization of remaining afferents, rather than by influencing denervation supersensitivity.

Gangliosides--a new therapeutic agent against stroke and Alzheimer's disease

Gangliosides are glycosphingolipids localized to the outer leaflet of the plasma membrane of vertebrate cells. The highest ganglioside concentration of any organ is found in the mammalian brain, where the gangliosides are enriched in the neuronal membrane, particularly in the synapses. There are four major brain gangliosides with the same neutral tetrasaccharide core to which one to three sialic acids are linked--the simplest being the GM1-ganglioside. These gangliosides have been shown to have neuritogenic and neuronotrophic activity and to facilitate repair of neuronal tissue after mechanical, biochemical or toxic injuries. Mixtures of native bovine brain gangliosides were adopted for pharmacological use in the treatment of peripheral nerve damage, and GM1-ganglioside has been applied for the treatment of CNS injuries and diseases. Beneficial effects of GM1 have been documented in the treatment of stroke and spinal cord injuries, particularly when the treatment has been initiated within a few hours of the acute event. Continuous intraventricular infusion of GM1 has recently been shown to have a significant beneficial effect in Alzheimer disease of early onset (AD Type I).

Reduction of cerebral edema with GM1 ganglioside

Administration of exogenous gangliosides has been reported to accelerate neurite outgrowth in vitro, and to enhance peripheral nerve regeneration and central nervous system recovery subsequent to damage. After injury, facilitation of CNS recovery with GM1 ganglioside treatment has been postulated to be due to enhanced neuronal regeneration. Since maximal recovery is achieved when experimental animals are treated before injury with GM1 ganglioside, an alternative or parallel mechanism is that gangliosides are "protecting" the CNS by limiting the extent of damage (ie, cell loss, process degeneration, membrane disruption). This may be due to a reduction in the edema subsequent to injury. In this study, rats were treated for 2 days with 20 mg/kg/day of GM1 ganglioside. On the third day they were subjected to a unilateral lesion (mechanical) of one cerebral hemisphere and given another 20 mg/kg of GM1. On the fourth day brains were removed for analysis of edema resulting from the injury. In treated animals there was a significant reduction in edema as measured either in the entire injured hemisphere (23%) or in the area of injury (33%). No effect was seen outside the damaged area. Since exogenous gangliosides can spontaneously "insert" into membranes, it is postulated that the effect of the GM1 may be due to alterations of membrane processes (eg, lipid hydrolysis, phospholipase activation, levels and membrane action of arachidonic acid, ionic permeation) that are characteristic of edema.

GM1 ganglioside enhances regrowth of noradrenaline nerve terminals in rat cerebral cortex lesioned by the neurotoxin 6-hydroxydopamine

The effect of exogenous GM1 ganglioside on selectively noradrenaline-denervated rat cerebral cortex was investigated by measuring the spatial distribution of endogenous noradrenaline levels and by fluorescence histochemical analysis. A local noradrenaline denervation was produced by intracortical infusion of the selective catecholamine neurotoxin 6-hydroxydopamine for 3 or 7 days. The neurotoxin infusion caused an almost complete noradrenaline denervation in a restricted area around the infusion point as reflected by an almost complete long-term disappearance of noradrenaline nerve terminals and reduction of noradrenaline levels. There was with time a slow recovery of the levels, most likely related to a spontaneous noradrenaline nerve terminal regeneration. Post-treatment for 1 week with GM1 had very small effects on the 6-hydroxydopamine-induced reduction of the noradrenaline levels, while pretreatment with GM1 for 3 days before the neurotoxin infusion and continuing the GM1 administration for another 7-14 days significantly enhanced noradrenaline recovery, as observed both bio- and histochemically. GM1 had no effect on the 6-hydroxydopamine-induced noradrenaline depletion acutely, indicating that GM1 does not interfere with the direct neurotoxic actions of 6-hydroxydopamine. The present results thus indicate that exogenous GM1 enhances regrowth of noradrenaline nerve terminals which may be due to a regrowth stimulatory effect (regeneration/collateral sprouting) and/or related to protective actions of GM1 against retrograde degeneration of noradrenaline axons following the neurotoxin-induced lesion.

Effect of GM1 ganglioside treatment on postlesion responses of cholinergic enzymes in rat hippocampus after various partial deafferentations

The effect of intramuscular administration of monosialoganglioside (GM1) on postlesion responses of choline acetyltransferase and acetylcholinesterase activity in partially deafferented rat hippocampus was studied at various survival times. Lesions partially destroying the medioventral, septal area, or lesions performed in supracallosal stria including corpus callosum and cingulum evoked cholinergic denervation of the hippocampus, while those made in entorhinal cortex resulted in partial glutamatergic deafferentation. GM1 treatment potentiates the responses of both cholinergic enzymes, independently of whether the partial deafferentation was homo- or heterotypical. These data indicate that GM1 may facilitate the regrowth of new cholinergic nerve terminals. However, an effect on other compensatory processes, especially in the first postoperative period, is also possible.

GM1 ganglioside-induced recovery of nigrostriatal dopaminergic neurons after MPTP: an immunohistochemical study

The administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to mice results in the loss of dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) from the mouse striatum and a loss of cells containing tyrosine hydroxylase (TH)-immunoreactivity from the substantia nigra. The cells that remained in the nigra after MPTP treatment were smaller in diameter than normal cells. Treatment with GM1 ganglioside beginning 24 h after establishing the MPTP lesion resulted in partial restoration of DA and DOPAC content in the striatum and an increase in the diameter of the TH-immunoreactive nigra cells. It appears, therefore, that treatment of MPTP-intoxicated mice with GM1 ganglioside results in the partial restoration of both the biochemistry and morphology of dopaminergic neurons.

Recruitment and early treatment in a multicenter study of acute spinal cord injury

STUDY DESIGN

Post hoc secondary analysis of data from 1992 to 1998 in the trial of Sygen in Acute Spinal Cord Injury.

OBJECTIVES

Quasi-epidemiologic understanding of injury and treatment patterns and of recruitment in an SCI trial. No drug efficacy results.

SUMMARY OF BACKGROUND DATA

The most recent large epidemiologic study was the National SCI Database by Stover and colleagues around 1980.

METHODS

Emphasis on descriptive, rather than inferential, statistics: consistent with secondary analysis.

RESULTS

The study involved 760 patients at 28 centers in North America. Cervical injuries were more common than thoracic, and complete injuries were more common than incomplete injuries. Recruitment in the complete cervical stratum was 332, but the incomplete thoracic strata had only 31 patients combined. Vital signs at arrival and on randomization show fair stability. Clock times show more injuries on weekends and nights but suggest immediate attention was given. Elapsed times to treatment (especially EMT and Medevac arrival) are short. The rate of direct admission to tertiary centers, traction weight, and time to surgery vary among centers. Inpatient rehabilitation appeared driven by insurance in addition to severity.

CONCLUSIONS

The imbalances in favor of cervical and of complete injuries would make it hard for studies to attain results for SCI in general. The vital signs and time patterns suggest local protocol-driven stabilization to prevent secondary physiologic injury early after SCI. Some features of care vary among centers, but the sparseness of prospective data in specific injury and treatment categories suggests that treatment guidelines have limited empirical support and should be made cautiously.

Acute effects of GM1 ganglioside: reduction in both behavioral asymmetry and loss of Na+, K+-ATPase after nigrostriatal transection

GM1 ganglioside injections (i.p.) reduce amphetamine-induced asymmetric rotation in rats 48 h after a partial unilateral transection of the nigrostriatal pathway. We found that this reduction was maximal when rats received their first GM1 injection within 2 h after surgery. Rats injected 4-12 h after surgery, or rats only pretreated with GM1, showed no significant effect on rotation. Striatal membrane Na+,K+-ATPase in rats injected with GM1 0-2 h after hemitransection showed only a 10% loss in activity (versus the untransected hemisphere) as compared to control losses of 38%. The maintenance of membrane Na+,K+-ATPase activity in GM1-treated rats may be one mechanism by which a balance between hemispheres in striatal dopaminergic transmission is preserved, resulting in reduced asymmetric rotation. The observation that there is a critical postsurgical period when GM1 administration results in optimal functional recovery supports our hypothesis that gangliosides are exerting an acute effect on damaged CNS tissue. This acute effect is further evidenced by the reduced loss of membrane Na+,K+-ATPase following injury.

The functional recovery of damaged brain: the effect of GM1 monosialoganglioside

In the present study the topology and the biochemical mechanisms underlying the functional recovery of the dopaminergic nigrostriatal system is further analyzed. Rats with unilateral hemitransection were treated with 30 mg/kg GM1 monosialoganglioside or with its internal ester derivative for different periods of time. GM1 enhances 3H-dopamine uptake in striatal synaptosomes of the lesioned side, and the enhancement of dopamine uptake precedes that of striatal tyrosine hydroxylase activity. The above biochemical effects are accompanied by changes in behavioral- and electrophysiological-related parameters. The effect of GM1 on striatal tyrosine hydroxylase of the lesioned side disappears when the ascending dopaminergic fibers are extensively lesioned. This suggests that the source of regrowing dopaminergic nerve terminals in the striatum of partially lesioned rats resides mainly in the intact axons remaining in the ipsilateral side. When GM1 is injected into partially lesioned rats kept in darkness, no effect on tyrosine hydroxylase activity is observed. This indicates that the mechanism through which GM1 acts involves a normal light-dark cycle.

Parkinson's disease: improved function with GM1 ganglioside treatment in a randomized placebo-controlled study

BACKGROUND/OBJECTIVE

Studies in animal models of Parkinson's disease (PD) suggest that GM1 ganglioside treatment can restore neurologic and dopaminergic function. In view of positive preclinical findings and the results of a previous open-label study demonstrating efficacy of GM1 in PD patients, this study compared effects of GM1 ganglioside and placebo on motor functions in PD patients.

METHODS

Forty-five patients with mild to moderate PD were studied. The primary efficacy measure was change in the Unified Parkinson's Disease Rating Scale (UPDRS) motor score. After three independent baseline assessments, patients received IV infusion of the test drug (1,000 mg GM1 or placebo) and then self-administered either GM1 or placebo twice daily (200 mg/day, subcutaneously) for 16 weeks. Patients were examined during monthly follow-up visits.

RESULTS

There was a significant difference between groups in UPDRS motor scores at 16 weeks (p=0.0001). The activities of daily living portion of the UPDRS (off-period assessment) also showed a significant effect in favor of the GM1-treated patients (p=0.04). GM1-treated patients also had significantly greater mean improvements than placebo-treated patients in performance of timed motor tests including tests of arm, hand, and foot movements, and walking. GM1 was well tolerated and no serious adverse events were reported.

CONCLUSIONS

This study demonstrates that GM1 ganglioside treatment enhances neurologic function significantly in PD patients. Further study is warranted to evaluate long-term effects of GM1 in PD patients and to elucidate further the mechanisms underlying patient improvements.

Gangliosides and neurotrophic factors in neurodegenerative diseases: from experimental findings to clinical perspectives

A large body of experimental data suggests that neurotrophic molecules and/or substances that facilitate their action could be pharmaceutical agents for neurodegenerative pathologies. In particular, it has been demonstrated that nerve growth factor (NGF) exerts a physiological role for forebrain cholinergic neurons, while brain-derived neurotrophic factor (BDNF) seems to play a relevant role in rescuing dopaminergic neurons following damage. In addition, gangliosides are reported to potentiate neurotrophic factor effects in vitro as well as in vivo. In this study we examined the effects of the monosialoganglioside GM1 in different experimental models. The responsiveness of forebrain cholinergic neurons following NGF +/- GM1 was evaluated by assessing choline acetyltransferase (ChAT) activity in hippocampus, septal area and striatum of behaviorally impaired 24-month-old rats. NGF was intracerebroventricularly (i.c.v.) infused for 2 weeks while GM1 was given systemically for 3 weeks, starting from the beginning of NGF infusion. Moreover, the possible protective effects of GM1 were assessed following exposure of cultured cerebellar granule cells and dopaminergic mesencephalic neurons to different doses of 6-OH-DOPA, a metabolite of the dopamine pathway which has excitotoxic properties and has been hypothesized to participate in the pathology of Parkinson's disease. GM1 treatment to aged rats was seen to potentiate the NGF-induced increase of ChAT activity in the striatum ipsilateral to the NGF infusion. Moreover, in the striatum contralateral to the NGF infusion, GM1 increased ChAT activity above the control values, whereas NGF treatment alone did not affect enzymatic activity. GM1 treatment of cerebellar granule cells and mesencephalic neurons counteracted the dose- and time-dependent neurotoxicity of 6-OH-DOPA. These data support the notion that GM1 might prove useful in treating those pathological conditions where trophic factor deficits and/or excitotoxin-related toxicity play an important role.