New drug may prevent cognitive decline in Parkinson’s disease: ScienceAlert

A characteristic feature of Parkinson’s disease is a decline in motor skills, which regularly manifests itself in the form of slowness, rigidity and tremors. However, the disease often also affects other neurological functions, affects mood and leads to a deterioration in cognition.

A drug that blocks a key receptor linked to blood pressure has shown promise in restoring memory in models of vascular dementia, inspiring researchers at the University of Arizona to test the treatment in mice Parkinson’s-similar symptoms.

The short peptide, called PNA5, is an attractive drug choice because of its affinity for its target and its ability to be safely broken down in the body. The researchers analyzed the mice’s memories and tissue samples to determine whether any changes were due to the drug.

The team concluded that PNA5 doses reversed some signs of cognitive decline in the mice, while a reduction in the activity of immune cells called microglia, which are thought to contribute to cognitive decline, was observed in their hippocampus got into full swing.

“With PNA5 we are targeting cognitive symptoms, but more specifically we are trying to prevent further degeneration,” says neurobiologist Kelsey Bernard. “By taking the protective route, we can hopefully prevent cognitive decline from continuing.”

The treatment in the mice was enough to improve recognition memory and spatial working memory, the researchers found. The loss of brain cells in their hippocampus was also slowed by the introduction of PNA5.

By calming microglial cells into a more normal state, PNA5 is thought to be able to reduce inflammation in the brain and stop some of the damage caused by the body’s out-of-control defense system.

“Normally, microglia look for viruses or injuries and secrete substances that ward off the damage,” says Bernard.

“In Parkinson’s disease, when microglia are constantly activated, they can cause further damage to surrounding tissue. We see this in Parkinson’s brains, particularly in regions associated with cognitive decline.”

PNA5 is made in the lab by building on the vasoconstrictor hormone angiotensin, and researchers have already made progress in making it penetrate the brain and last longer.

Although these are promising results, the drug’s safety and effectiveness need to be proven in humans. There is still much work to be done to understand how PNA5 affects the cells in our own brains.

While some of the debilitating symptoms of Parkinson’s disease can be well managed with proper care, there is still nothing that can be done about the dementia aspect of the disease. This study, along with other promising initiatives, gives us more hope for the future.

“When patients are diagnosed with Parkinson’s disease, 25 to 30 percent already have mild cognitive impairment,” says neurodevelopmental biologist Lalitha Madhavan. “As the disease progresses, 50-70 percent of patients complain of cognitive problems.”

“The sad thing is that we don’t have a clear way to treat cognitive decline or dementia in Parkinson’s disease.”

The research was published in Experimental Neurology.