Isradipine, a drug commonly used to treat high blood pressure, could slow down or stop the progression of Parkinson’s disease, reported newspapers.
Parkinson’s disease is thought to be caused by a deficiency of dopamine in parts of the brain. The Times and The Guardian both quoted James Surmeier, the lead researcher, as saying: “Our hope is that this drug will protect dopamine neurons, so that if you began taking it early enough you won’t get Parkinson’s disease, even if you were at risk.”
This study was carried out in animals and these findings cannot be directly extrapolated to humans.
The disease that was treated was also “Parkinson’s like”, and not actual Parkinson’s disease and we would need studies in Parkinson’s disease in humans before we could draw conclusions about the effects of oral isradipine, a calcium channel blocking drug, on this disease.
Where did the story come from?
The research was conducted by James Surmeier and his team at the Northwestern University’s Feinberg School of Medicine in Chicago, Illinois, USA. The research was published in a peer-reviewed medical journal, Nature .
What kind of scientific study was it?
This research was a study conducted in a laboratory in mice. There were two parts to the study. In the first, slices from adult mouse brains were exposed to a pesticide (rotenone) which is believed to cause "Parkinson’s-like disease". Some of these slices had been pre-treated with isradipine. The effects of the toxin on the "treated" brain cells were compared with those that had not been ‘treated’.
In the second part, live mice were given isradipine for seven days while others were given placebo control pellets. The mice were then given a Parkinson’s-like disease by repeated injections with a toxin. The effects of treatment on dopamine-containing neurons and movement control were compared between treated and untreated mice.
What were the results of the study?
The researchers reported that isradipine "rejuvenated dopamine-containing neurons" in mice.
What interpretations did the researchers draw from these results?
The authors conclude that the observable "rejuvenation" of dopamine-containing neurons "points to a new strategy that could slow or stop the progression" of Parkinson’s disease.
What does the NHS Knowledge Service make of this study?
Parkinson’s disease is thought to be caused by a deficiency of the chemical transmitter dopamine in specific parts of the brain. As this research was conducted in animals, findings shouldn’t be extrapolated to humans.
Mice were exposed to toxins that are believed to cause Parkinson’s-like disease because of their effects on dopaminergic neurons and behaviour. It is not clear whether the unit of analysis in statistical tests was the mouse or a sample of brain tissue. Here we would expect to see similarities between samples if they came from the same mouse.
The research should be seen as a hypothesis-generating study as it provides information on which to design further studies. We need studies in humans before we can draw conclusions about the effects of oral isradipine on Parkinson’s disease.
Analysis by Bazian
Edited by NHS Website
Links to the headlines
The Times, 11 June 2007
The Guardian, 11 June 2007
The Independent, 11 June 2007
Links to the science
Nature 2007; 447:1081