Vascular defects appear to underlie the progression of Parkinson's
disease

Date:
November 13, 2021
Source:
Georgetown University Medical Center
Summary:
In an unexpected discovery, researchers have identified what appears
to be a significant vascular defect in patients with moderately
severe Parkinson's disease. The finding could help explain an
earlier outcome of the same study, in which the drug nilotinib was
able to halt motor and non-motor (cognition and quality of life)
decline in the long term.



FULL STORY ==========================================================================
In an unexpected discovery, Georgetown University Medical Center
researchers have identified what appears to be a significant vascular
defect in patients with moderately severe Parkinson's disease. The finding could help explain an earlier outcome of the same study, in which the
drug nilotinib was able to halt motor and non-motor (cognition and
quality of life) decline in the long term.


==========================================================================
The researchers say their finding, detailed in a study published November
12, 2021, in Neurology Genetics, suggests that blood vessel walls called
the blood brain barrier, which normally act as a crucial filter to
protect the brain against toxins as well as allow passage of nutrients
to nourish it, doesn't work correctly in some Parkinson's patients:
it prohibits toxins from leaving the brain and inhibits nutrients such
as glucose from entering. Perhaps even more damaging, the dysfunctional
barrier allows inflammatory cells and molecules from the body to enter
and damage the brain.

The research, the first longitudinal study to use such advanced
genomics, now provides investigators with a new target for therapeutic intervention in Parkinson's disease, says the study's senior author,
Charbel Moussa, MBBS, PhD, director of the Medical Center's Translational Neurotherapeutics Program.

The new discovery comes from the second part of a Phase II clinical trial
that featured next generation whole genome sequencing of the cerebrospinal fluid of 75 Parkinson's patients, before and after treatment with a
repurposed leukemia drug, nilotinib, or placebo.

This study lasted 27 months; the initial trial was double-blinded and
patients were randomized to either placebo, or 150mgs or 300mgs nilotinib
for 12 months.

The patients had severe Parkinson's disease; all treated with optimal
standard of care and many (30%) had also used the most sophisticated
treatments possible, such as deep brain stimulation. The second part of
the study employed an adaptive design and all participants had a 3-month
drug washout period before re-randomization to either 150mgs or 300mgs
for an additional 12 months.

After 27 months, nilotinib was found to be safe, and patients who
received nilotinib showed a dose-dependent increase of dopamine, the
chemical lost as a result of neuronal destruction.

"It appeared nilotinib halted motor and non-motor decline in the patients taking the 300mgs higher dose," says Moussa. The clinical outcomes of
this study was published in Movement Disorders in March 2021.

The current part of the study just published, examined the cerebrospinal
fluid of patients via epigenomics, which is a systematic analysis of the
global state of gene expression, in correlation with continuing clinical outcomes. The new analysis helps explain the clinical findings.

Nilotinib inactivated a protein (DDR1) that was destroying the ability of
the blood brain barrier to function properly. When DDR1 was inhibited,
normal transport of molecules in and out of the brain filter resumed,
and inflammation declined to the point that dopamine, the neurotransmitter depleted by the disease process, was being produced again.

Moussa and his team have long been working on the effects that nilotinib (Tasigna) may have on neurodegeneration, including Alzheimer's
and Parkinson's diseases. The drug was approved in 2007 for chronic
myelogenous leukemia (CML), but Moussa reasoned that its mechanism of
action may help the brain destroy toxins that develop in the brains of
patients with neurodegenerative disorders.

"Not only does nilotinib flip on the brain's garbage disposal system
to eliminate bad toxic proteins, but it appears to also repair the
blood brain barrier to allow this toxic waste to leave the brain
and to allow nutrients in," Moussa explains. "Parkinson's disease
is generally believed to involve mitochondrial or energy deficits
that can be caused by environmental toxins or by toxic protein
accumulation; it has never been identified as a vascular disease."
"To our knowledge, this is the first study to show that the body's
blood brain barrier potentially offers a target for the treatment for Parkinson's disease," Moussa says. "Much work remains to be done, but just knowing that a patient's brain vascular system is playing a significant
role in the progression of the disease is a very promising discovery." ========================================================================== Story Source: Materials provided by
Georgetown_University_Medical_Center. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Alan J. Fowler, Jaeil Ahn, Michaeline Hebron, Timothy Chiu,
Reem Ayoub,
Sanjana Mulki, Habtom Ressom, Yasar Torres-Yaghi, Barbara Wilmarth,
Fernando L. Pagan, Charbel Moussa. CSF MicroRNAs Reveal Impairment
of Angiogenesis and Autophagy in Parkinson Disease. Neurology
Genetics, 2021; 7 (6): e633 DOI: 10.1212/NXG.0000000000000633 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211113072244.htm

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