A new study provides at least one explanation for the sudden onset of tremors and other symptoms of Parkinson’s disease.
Researchers from the University of Manchester discovered that a small stroke, also known as a silent stroke, can cause Parkinson’s disease in mice.
Common characteristics of a stroke include symptoms that present suddenly. These include numbness or weakness of face, arm or leg — especially on one side of the body; confusion, trouble speaking or understanding; trouble seeing in one or both eyes; trouble walking, dizziness, loss of balance or coordination; or a severe headache with no known cause.
In the case of a silent stroke, these typical symptoms are not present as a person shows no outward signs. Silent strokes occur when a blood vessel in the brain is blocked for only a very short amount of time.
Often, an individual will not know that a neurological event has occurred. However, it now appears one of the lasting effects of a silent stroke can be the death of dopaminergic neurons in the substantia nigra in the brain, which is an important region for movement coordination.
“At the moment we don’t know why dopaminergic neurons start to die in the brain and therefore why people get Parkinson’s disease. There have been suggestions that oxidative stress and aging are responsible,” said lead researcher Emmanuel Pinteaux, Ph.D.
“What we wanted to do in our study was to look at what happens in the brain away from the immediate area where a silent stroke has occurred and whether that could lead to damage that might result in Parkinson’s disease.”
As part of the research, investigators induced a mild stroke similar to a silent stroke in the striatum area of the brain in mice. They found there was inflammation and brain damage in the striatum following the stroke, which they had expected.
What the researchers didn’t expect was the impact on another area of the brain, the substantia nigra. When they analyzed the substantia nigra they recorded a rapid loss of Substance P (a key chemical involved in its functions) as well as inflammation.
The team then analyzed changes in the brain six days after the mild stroke and found neurodegeneration in the substantia nigra. Dopaminergic neurones had been killed.
Researchers say that while experts understand the dramatic brain damage that accompanies the inflammatory process following a stroke, they were surprised to learn of brain damage away from the stroke’s focal point.
“Our work identifying that a silent stroke can lead to Parkinson’s disease shows it is more important than ever to ensure stroke patients have swift access to anti-inflammatory medication. These drugs could potentially either delay or stop the on-set of Parkinson’s disease,” Pinteaux said.
“What our findings also point to is the importance of maintaining a healthy lifestyle. There are already guidelines about exercise and healthy eating to help reduce the risk of having a stroke and our research suggests that a healthy lifestyle can be applied to Parkinson’s disease as well.”
Their findings have been published in the journal Brain Behavior and Immunity.
Source: University of Manchester