Nerve growth factor, ganglioside and vitamin E reverse glutamate cytotoxicity in hippocampal cells

Amyloid-β induced toxicity involves ganglioside expression and is sensitive to GM1 neuroprotective action

The effect of Aβ25-35 peptide, in its fibrillar and non-fibrillar forms, on ganglioside expression in organotypic hippocampal slice cultures was investigated. Gangliosides were endogenously labeled with D-[1-C(14)] galactose and results showed that Aβ25-35 affected ganglioside expression, depending on the peptide aggregation state, that is, fibrillar Aβ25-35 caused an increase in GM3 labeling and a reduction in GD1b labeling, whereas the non-fibrillar form was able to enhance GM1 expression. Interestingly, GM1 exhibited a neuroprotective effect in this organotypic model, since pre-treatment of the hippocampal slices with GM1 10 μM was able to prevent the toxicity triggered by the fibrillar Aβ25-35, when measured by propidium iodide uptake protocol. With the purpose of further investigating a possible mechanism of action, we analyzed the effect of GM1 treatment (1, 6, 12 and 24h) upon the Aβ-induced alterations on GSK3β dephosphorylation/activation state. Results demonstrated an important effect after 24-h incubation, with GM1 preventing the Aβ-induced dephosphorylation (activation) of GSK3β, a signaling pathway involved in apoptosis triggering and neuronal death in models of Alzheimer's disease. Taken together, present results provide a new and important support for ganglioside participation in development of Alzheimer's disease experimental models and suggest a protective role for GM1 in Aβ-induced toxicity. This may be useful for designing new therapeutic strategies for Alzheimer's treatment.

The neuroprotective effects of NGF combined with GM1 on injured spinal cord neurons in vitro

Monosialoganglioside (GM1) has been considered to have a neurotrophic factor-like activity. Nerve growth factor (NGF), a member of the neurotrophin family, is essential for neuronal survival, differentiation and maturation. The aim of the present study was to investigate whether co-administration of GM1 and NGF reverses glutamate (Glu) neurotoxicity in primary cultured rat embryonic spinal cord neurons. Spinal cord neurons were exposed to Glu (2 mmol/l), Glu (2 mmol/l) plus GM1 (10 mg/ml), Glu (2 mmol/l) plus NGF (10 ng/ml), Glu (2 mmol/l) plus GM1 (5 mg/ml) and NGF (5 ng/ml) and then processed for detecting intracellular concentrations of Ca2+([Ca2+]i) by confocal laser scanning microscopy and growth associated protein 43 (GAP43) mRNA by RT-PCR. The fluorescent intensity in Glu plus GM1 and NGF incubated neurons was the lowest as compared with that in other groups. The expression of GAP43 mRNA in Glu plus GM1 and NGF incubated neurons was the highest as compared with that in other groups. These results implicated that GM1 and NGF have synergistic neuroprotective effects on spinal cord neurons with excitotoxicity induced by Glu in vitro.

GM1 and NGF modulate Ca2+ homeostasis and GAP43 mRNA expression in cultured dorsal root ganglion neurons with excitotoxicity induced by glutamate

Monosialoganglioside (GM1) has been considered to have a neurotrophic factor-like activity. Nerve growth factor (NGF), a member of the neurotrophin family, is essential for neuronal survival, differentiation and maturation. The aim of the present study was to investigate whether co-administration of GM1 and NGF reverses glutamate (Glu) neurotoxicity in primary cultured rat embryonic dorsal root ganglion (DRG) neurons. DRG neurons were exposed to Glu (2 mmol/1), Glu (2 mmol/1) plus GM1 (10 microg/ml), Glu (2 mmol/l) plus NGF (10 ng/ml), Glu (2 mmol/l) plus GM1 (5 microg/ml) and NGF (5 ng/ml) and then processed for detecting intracellular concentrations of Ca2+ ([Ca2+] i) by confocal laser scanning microscopy and growth-associated protein 43 (GAP43) mRNA by RT-PCR. The fluorescent intensity in Glu plus GM1 and NGF incubated neurons was the lowest as compared with that in other groups. The expression of GAP43 mRNA in Glu plus GM1 and NGF incubated neurons was the highest as compared with that in other groups. These results implicated that GM1 and NGF have synergistic neuroprotective effects on DRG neurons with excitotoxicity induced by Glu in vitro.

Alpha-tocopherol supplementation prevents the exercise-induced reduction of serum paraoxonase 1/arylesterase activities in healthy individuals

OBJECTIVE

To investigate PON 1/Aryl activities in basketball players with or without alpha-T supplementation pre- and post-training. Vitamin E (alpha-tocopherol, alpha-T) reduces lipid peroxidation. Paraoxonase 1/arylesterase (PON 1/Aryl) activities are closely related to oxidation and atherogenesis.

SUBJECT/METHODS

Blood was obtained from 10 players pre- (group A), post-exercise (group B) and after 1 month on alpha-T (200 mg per 24 h orally) supplementation pre- (group C) and post-exercise (group D). Lactate, pyruvate, muscle enzyme activities, creatine kinase, lactate dehydrogenase and total antioxidant status (TAS) were measured with commercial kits. Catecholamines and alpha-T were determined with high-performance liquid chromatography methods and PON 1/Aryl activities spectrophotometrically.

RESULTS

Lactate, pyruvate, muscle enzyme activities and catecholamines were increased (P<0.001) in all groups post-training. Alpha-T levels remained unaltered pre- vs post-exercise. TAS was decreased in all the groups post training. PON 1/Aryl activities were significantly decreased post-exercise (group B) (PON1: 65+/-12 U min(-1) ml(-1), Aryl: 58+/-14 KU min(-1) ml(-1)) as compared to those pre-exercise (group A) (PON1: 142+/-16 U min(-1) ml(-1), Aryl: 114+/-12 KU min(-1) ml(-1), P<0.001). In contrast, the studied enzyme activities remained practically unaltered after alpha-T supplementation pre- vs post-training. Both enzyme activities positively correlated to TAS (r=0.60, P<0.001).

CONCLUSIONS

Alpha-T supplementation may result in protection of the enzyme PON 1/Aryl activities from free radical production.

The effect of α-Tocopherol supplementation on training-induced elevation of S100B protein in sera of basketball players

OBJECTIVE

To investigate the effect of alpha-Tocopherol (alpha-T) supplementation on S100B elevated serum levels in basketball players' training.

DESIGN

Blood was obtained from 10 basketball players pre-exercise (group A), post-exercise (group B) and after 30 days on alpha-T (200 mg/24 h orally) supplementation pre- (group C) and post-training (group D). Blood samples were taken for the evaluation of total antioxidant status (TAS), alpha-T and catecholamines in plasma and S100B and muscle enzyme levels in serum.

METHODS

TAS, muscle enzymes: creatine kinase (CK), lactate dehydrogenase (LDH), and S100B protein levels were measured with commercial kits, whereas alpha-T and catecholamine levels with HPLC methods.

RESULTS

TAS was found higher in the groups with alpha-T addition (groups C and D) than in the other ones. On the contrary, CK, LDH and S100B were remarkably lower (116.8+9.5 U/L, 427+22 U/L, 0.18+0.04 microg/L, respectively) in group D than those in group B (286+12 U/L, 688+26 U/L, 0.28+0.06 microg/L, p<0.001, respectively). S100B levels were negatively correlated with TAS (r=-0.64, p<0.001) and positively with CK levels (r=0.58, p<0.001).

CONCLUSIONS

alpha-T supplementation may reduce S100B increased release from muscle and nerves induced by training. S100B serum evaluation may be a useful biomarker for the effect of training on the participation of the neuromuscular system.

Monosialoganglioside (GM1) attenuates the behavioural effects of long-term haloperidol administration in supersensitive rats

In the present study we investigated the effects of co-administration of GM(1) (15.0 mg/kg, twice daily, for 30 days) and haloperidol (1.0 mg/kg, twice daily, for 30 days), as well as the effects of a 5-day treatment with this dose of GM(1) after withdrawal from haloperidol in rats. The animals were evaluated in the open-field test and apomorphine-induced stereotyped behaviour. The results show that GM(1) was able to attenuate dopaminergic supersensitivity evaluated by the locomotion frequency at 24 and 48 h after the withdrawal from haloperidol. On the other hand, rearing frequency was changed neither by haloperidol nor by GM(1.) In haloperidol-treated rats immobility time differs from 30 min observation session in comparison with the following sessions after the withdrawal from neuroleptic. Apomorphine-induced stereotyped behaviour produced a significant increase in scores of haloperidol-withdrawn rats. GM(1) did not modify the haloperidol effects and did not change the dopamine receptor affinity to apomorphine 100 h from abrupt neuroleptic withdrawal.

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.

Nerve growth factor signaling, neuroprotection, and neural repair

Nerve growth factor (NGF) was discovered 50 years ago as a molecule that promoted the survival and differentiation of sensory and sympathetic neurons. Its roles in neural development have been characterized extensively, but recent findings point to an unexpected diversity of NGF actions and indicate that developmental effects are only one aspect of the biology of NGF. This article considers expanded roles for NGF that are associated with the dynamically regulated production of NGF and its receptors that begins in development, extends throughout adult life and aging, and involves a surprising variety of neurons, glia, and nonneural cells. Particular attention is given to a growing body of evidence that suggests that among other roles, endogenous NGF signaling subserves neuroprotective and repair functions. The analysis points to many interesting unanswered questions and to the potential for continuing research on NGF to substantially enhance our understanding of the mechanisms and treatment of neurological disorders.

Systemic treatment with GM1 ganglioside improves survival and function of cryopreserved embryonic midbrain grafted to the 6-hydroxydopamine-lesioned rat striatum

Cryopreservation may allow long-term storage of embryonic ventral mesencephalon (VM) for neural transplantation. We investigated whether the ganglioside GM1 or the lazaroid tirilazad mesylate (U-74006F) could improve survival of grafts derived from cryopreserved VM in a rat model of Parkinson's disease. VM was dissected from rat embryos (E14-E15), frozen and stored in liquid nitrogen under controlled conditions, thawed, dissociated, and then grafted into the 6-hydroxydopamine-lesioned rat striatum. In Experiment I, VM fragments were exposed in vitro either to GM1 (100 microM) or to lazaroid (0.3 microM) during all preparative steps. In Experiment II, rats receiving GM1-pretreated VM were, in addition, treated systematically with GM1 (30 mg/kg) daily for 3.5 weeks. Rats grafted with untreated cryopreserved or fresh VM were used as controls, respectively. Rats receiving fresh VM control grafts showed complete recovery from lesion-induced rotations after 6 weeks whereas rats grafted with cryopreserved VM (untreated or pretreated) did not recover. Cryografts contained significantly less (18%, control; 23%, GM1; and 12%, lazaroid) tyrosine hydroxylase-positive cells compared to fresh grafts (1415 +/- 153; mean +/- SEM). Graft volume was also significantly smaller after cryopreservation. In contrast, with additional systemic GM1 treatment cryografts contained almost the same number of tyrosine hydroxylase-positive cells (376 +/- 85) as fresh grafts (404 +/- 56), which was significantly more than that of untreated cryografts (147 +/- 20), showed a significantly larger volume (0.15 mm(3)) compared to that of untreated grafts (0.08 mm(3)) (fresh controls, 0.19 mm(3)), and induced significant and complete functional recovery in the rotation test. In conclusion, systemic treatment of rats with GM1 improved the low survival and functional inefficacy of grafts derived from cryopreserved VM whereas tissue pretreatment alone with either GM1 or lazaroid was not effective.