ABSTRACT
Title
Chronic caffeine intake reduces the survival in a mice model of amyotrophic lateral sclerosis.
Authors
R.L. Potenza, A. Ferrante, M. Armida, A. Pèzzola, A. Matteucci, P. Popoli
Dept.of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanità, Rome, Italy
Dept.of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanità, Rome, Italy
Abstract
Amyotrophic lateral sclerosis (ALS) is an incurable disease characterized by progressive degeneration of motor neurons (Cleveland and Rothstein, 2001).Although there are several hypotheses for the cause of ALS,the precise mechanism of ALS pathogenesis is still far from being well understood.
Caffeine (a methylxanthine which non-selectively antagonizes adenosine receptors) is the most widely used psychoactive substance in the worldand its chronic consumption has proven protective towards neurodegenerative diseases such as Parkinson (Ascherio et al., 2001) and Alzheimer disease (Rosso et al., 2008). Its neuroprotective effect is mimicked by antagonists of adenosine A2A receptors (A2ARs), which are the main molecular targets of chronic caffeine consumption (Quarta et al., 2004). Some evidence indicates that A2AR blockade could be beneficial in ALS (Mojsilovic-Petrovic et al.,2006). The present study was designed to determine whether chronic caffeine intake improved survival and/or motor performance of SOD1G93Amice.
Twenty SOD1G93A transgenic and 20 wild-type (wt) SOD1 transgenic mice bred by The Jackson Laboratory were used. Caffeine (0.3 mg/ml) or vehicle (normal water) were administered through drinking water from 65 days of age until death; mice received a daily caffeine dose (50 mg/kg) equivalent to approximately 500 mg intake (≈5 cups of coffee) by humans. A detailed assessment of onset of disease, motor behaviour and body weight was performed in vehicle- and caffeine-treated SOD1G93Amice and the expression of A2A receptor, GLT1 and GFAP were evaluated in the spinal cord of end-stage mice by western blotting.
As expected, SOD1G93Amice compared to WT mice showed a gradual decrease in their body weightand a significant worsening of motor symptoms, tested using an acceleration rotarod device, was observed after 10 weeks of life in both groups of SOD1G93A; neither symptoms was affected by chronic consumption of caffeine. Interestingly, western blot analysis showed a significant reduction of A2ARs in the spinal cord of “control” (i.e. drinking normal water) SOD1G93Avs. WT mice (p<0.0001) and,to the best of our knowledge, this result is here reported for the first time.
To our surprise, caffeine intake significantly shortened the survival of SOD1G93Amice (Logrank Test p=0.01) and induced anon-significant anticipation ofdisease onset (measured as the time at which a 10% decline in rotarod performance is observed). As expected, we observed an increase in GFAP immunoreactivity (indicative of astroglial hypertrophy and hyperplasia) and a downregulation of the glial glutamate transporter GLT1 in the spinal cord of end stage G93Amice. Such changes, however, were unaffected by caffeine intake.
The main finding of our study, namely that caffeine intake shortens the survival of ALS mice, has at least two possible explanations. The first one is that the pro-toxic effects of caffeine do not depend on A2AR blockade. The second possibility is that, contrarily to our hypothesis, it is the activation of A2ARs, instead of their blockade, that may be neuroprotective in ALS.
In conclusion, besides suggesting that caffeine consume should be rigorously controlled in ALS patients, these data suggest that, although in an opposite way than the expected one, A2ARs may play an important role in this disease. On the basis of these considerations, the effects of A2AR agonists in models of ALS should be evaluated.
Cleveland and Rothstein (2001).Nat Rev Neurosci.2,806-19.
Ascherio et al. (2001).Ann Neurol. 50,56-63.
Rosso et al. (2008).Am J Alzheimers Dis Other Demen.23,417-22.
Quarta et al. (2004).J Neurochem.91,873-80.
Mojsilovic-Petrovic et al. (2006).J Neurosci.26,9250-63.
Caffeine (a methylxanthine which non-selectively antagonizes adenosine receptors) is the most widely used psychoactive substance in the worldand its chronic consumption has proven protective towards neurodegenerative diseases such as Parkinson (Ascherio et al., 2001) and Alzheimer disease (Rosso et al., 2008). Its neuroprotective effect is mimicked by antagonists of adenosine A2A receptors (A2ARs), which are the main molecular targets of chronic caffeine consumption (Quarta et al., 2004). Some evidence indicates that A2AR blockade could be beneficial in ALS (Mojsilovic-Petrovic et al.,2006). The present study was designed to determine whether chronic caffeine intake improved survival and/or motor performance of SOD1G93Amice.
Twenty SOD1G93A transgenic and 20 wild-type (wt) SOD1 transgenic mice bred by The Jackson Laboratory were used. Caffeine (0.3 mg/ml) or vehicle (normal water) were administered through drinking water from 65 days of age until death; mice received a daily caffeine dose (50 mg/kg) equivalent to approximately 500 mg intake (≈5 cups of coffee) by humans. A detailed assessment of onset of disease, motor behaviour and body weight was performed in vehicle- and caffeine-treated SOD1G93Amice and the expression of A2A receptor, GLT1 and GFAP were evaluated in the spinal cord of end-stage mice by western blotting.
As expected, SOD1G93Amice compared to WT mice showed a gradual decrease in their body weightand a significant worsening of motor symptoms, tested using an acceleration rotarod device, was observed after 10 weeks of life in both groups of SOD1G93A; neither symptoms was affected by chronic consumption of caffeine. Interestingly, western blot analysis showed a significant reduction of A2ARs in the spinal cord of “control” (i.e. drinking normal water) SOD1G93Avs. WT mice (p<0.0001) and,to the best of our knowledge, this result is here reported for the first time.
To our surprise, caffeine intake significantly shortened the survival of SOD1G93Amice (Logrank Test p=0.01) and induced anon-significant anticipation ofdisease onset (measured as the time at which a 10% decline in rotarod performance is observed). As expected, we observed an increase in GFAP immunoreactivity (indicative of astroglial hypertrophy and hyperplasia) and a downregulation of the glial glutamate transporter GLT1 in the spinal cord of end stage G93Amice. Such changes, however, were unaffected by caffeine intake.
The main finding of our study, namely that caffeine intake shortens the survival of ALS mice, has at least two possible explanations. The first one is that the pro-toxic effects of caffeine do not depend on A2AR blockade. The second possibility is that, contrarily to our hypothesis, it is the activation of A2ARs, instead of their blockade, that may be neuroprotective in ALS.
In conclusion, besides suggesting that caffeine consume should be rigorously controlled in ALS patients, these data suggest that, although in an opposite way than the expected one, A2ARs may play an important role in this disease. On the basis of these considerations, the effects of A2AR agonists in models of ALS should be evaluated.
Cleveland and Rothstein (2001).Nat Rev Neurosci.2,806-19.
Ascherio et al. (2001).Ann Neurol. 50,56-63.
Rosso et al. (2008).Am J Alzheimers Dis Other Demen.23,417-22.
Quarta et al. (2004).J Neurochem.91,873-80.
Mojsilovic-Petrovic et al. (2006).J Neurosci.26,9250-63.