Researchers at Cambridge University have now developed ultra-powerful magnetic resonance imaging (MRI) scanners that can aid in determining where new drug regimens can be used for symptoms of Parkinson's disease and other similar neuronal conditions, that were previously considered untreatable, a university press release said.
Parkinson's disease is a progressive disorder of the nervous system that usually starts with a slight tremor in one hand. The damage has already begun inside the brain as neurons - brain cells- have begun to gradually degrade and die. This leads to a loss of a chemical called dopamine, secreted by neurons, leading to abnormal brain activity.
Symptoms usually worsen to rigid muscles, impaired posture, and even loss of unconscious movements such as blinking or smiling over some time. A condition called progressive supranuclear palsy (PSP) also shows similar symptoms and affects an individual's cognition.
Moving beyond L-DOPA
Conditions like Parkinson's and PSP cannot be cured. Medications such as L-DOPA have been used to replace the severe loss of dopamine seen in these conditions. But the treatment does not do much for non-motor symptoms such as memory and thinking problems.
Researchers have, therefore, turned their attention to noradrenaline - a chemical that plays an essential role in brain functions such as thinking, motivation, and engagement. "Noradrenaline is very important for brain function. All of our brain’s supply comes from a tiny region at the back of the brain called the locus coeruleus – which means ‘the blue spot’," said Professor James Rowe from the Department of Clinical Neurosciences. "It's a bit like two short sticks of spaghetti half an inch long: it's thin, it's small, and it's tucked away at the very base of the brain in the brain stem."
Professor Rowe's previous work has shown that individuals with PSP have lost as much as 90 percent of their locus coeruleus. By spotting the degradation of the region early on, one could hypothetically detect the disease early as well.
Limited Resolution of current MRI machines
However, the researchers faced the problem that the locus coeruleus was too small to be detected by the best MRI machines used in medical practice today. If clinicians can't see the region on a scan, they do not know if it has shrunken in size or not and if an individual is progressing towards a neuronal disease.
So, the researchers built a 7T MRI scanner using ultra-strong magnetic fields. In comparison, MRI scanners used in hospitals are usually 3T and can provide details on structures as big as a grain of rice. With a 7T scanner, the researchers could image structures the size of a grain of sand in sufficient detail. Using this higher resolution, the researchers were able to analyze the locus coeruleus in their subjects and correlate the severity of their condition with the damage to the region. The press release said that individuals with higher damage performed worse on cognitive tests.
Researchers believe that the damage to the locus coeruleus is caused due to build-up of a protein called tau. The same protein has been associated with Parkinson's disease. The loss of noradrenaline has also been associated with the accumulation of the tau protein, which leads to further breakdown of noradrenaline in the brain.
Professor Rowe and colleagues are currently conducting trials to see if noradrenaline drugs help PSP patients. The researchers say that not every PSP or Parkinson's disease patient might benefit from noradrenaline drugs. However, if the locus coeruleus is damaged, the drug will definitely help and the newly developed 7T MRI scanners will aid in determining which patients are likely to benefit from these new treatments.