Research funded by the US defence department is aiming to unpick the causes of neuropsychiatric problems associated with Parkinson’s.
Around half of Parkinson’s patients will experience neuropsychiatric problems, including cognitive and sleep issues, depression, anxiety, even psychosis.
A study backed by US$3m from the US Department for Defense is investigating the underlying causes of these issues. Veterans tend to develop Parkinson’s at a higher rate than the general population.
Changes in serotonin-producing neurons have often been linked to Parkinson’s in clinical studies, and research has found that serotonin neurons are unexpectedly capable of producing dopamine when exposed to L-DOPA, a common PD treatment. However, the serotonin neurons release dopamine in an uncontrolled way, leading to significant side effects.
“It’s almost as if the systems get hijacked and tip over into aberrant neuroplasticity,” researcher Christopher Bishop of Binghamton University says.
“The severity of the disease is the tipping point and adding treatment on top of disease progression.”
Due to the development of new techniques, researchers can directly modify specific cell types in animal models and study or stimulate those cell types with chemo-genetic tools.
So far, they have been able to demonstrate that animals subject to specific cellular changes show increased levels of anxiety.
In the long-term, their research could ultimately improve the lives of Parkinson’s patients and the management of symptoms.
The researchers have already identified several medications that could be repurposed to treat serotonin dysfunction in Parkinson’s, should their hypothesis prove true.
And, thanks to a partnership with the Muhammad Ali Parkinson Center, they also have access to a large Parkinson’s population, as well as extensive expertise in clinical trials.
“Non-motor symptoms of PD clearly come from an organic source,” Bishop says.
“As we investigated it further using our animal models and even postmortem human brains, we noticed the same plasticity in the movement system in the areas involved in neuropsychiatric, cognitive and sleep-related functions. There is a more global compensatory mechanism involved in the disease.”
Other institutions involved in this work include the Barrow Neurological Institute in Arizona and the University of Illinois in Chicago.
