Ulrike Dydak, a Purdue assistant professor of health sciences who specializes in medical imaging of neurodegenerative diseases, received more than $2 million through an Outstanding New Environmental Scientist Award (ONES) from the National Institute of Environmental Health Sciences. The five-year grant will help fund non-invasive neuroimaging techniques using magnetic resonance imaging to study manganese toxicity and lead to a better understanding of the neural system and the mechanism of this condition, which has similarities to Parkinson’s disease. Photo: Purdue University/Andrew Hancock |
People exposed to manganese in occupational settings such as
welding may not see signs for years that the element is toxic to their nervous
systems, but new medical imaging techniques being developed and tested by a Purdue University
professor could help reveal toxicity before symptoms appear that indicate
irreversible brain damage.
Ulrike Dydak, an assistant professor of health sciences who specializes
in medical imaging of neurodegenerative diseases, received more than $2 million
through an Outstanding New Environmental Scientist Award (ONES) from the
National Institute of Environmental Health Sciences, which is part of the
National Institutes of Health.
This career award is meant to provide a foundation for
outstanding scientists who are in the early, formative stages of their careers
in environmental health research. It was given to seven scientists nationally
this year to help them launch research programs that focus on human disease and
the influence of the environment.
The five-year grant will help fund Dydak’s non-invasive
neuroimaging techniques using magnetic resonance imaging, known as MRI, to
study manganese toxicity. The work could lead to a better understanding of the
neural system and the mechanism of manganese toxicity, which has similarities
to Parkinson’s disease.
“Patients with manganese intoxication—also known as
manganism and manganese-induced Parkinsonism—as well as patients with
idiopathic Parkinson’s disease, have motor control issues, tremors, and
problems walking,” Dydak says. “However, the patients with manganism
don’t respond to the medication used to manage Parkinson’s disease symptoms
because the two conditions have a different mechanism. Early diagnosis is
crucial for prevention, and our goal is to see if we can identify
pre-symptomatic biomarkers through new imaging techniques to create a
diagnostic tool and also learn more about the disease so patients can better
manage it.”
Those who are mostly affected by manganese intoxication work
in welding or smelting in the steel industry. There also is low-level exposure
from gasoline as well as the environment of steel plants. Manganese is an
element that is essential to neurological function, but too much is toxic and
can cause irreversible brain damage. It also has been found recently that low
amounts of manganese exposure can affect cognitive functions, such as short-term
memory or reaction time.
“So far, most studies on the toxicity of manganese and
other metals are performed in animal models,” she says. “If we can
improve medical imaging to observe specific changes in living human brain
chemistry and observe these changes over the long run, it will help create a
better understanding of this neurodegenerative disease and help people by
improving diagnostic and therapeutic tools.”
Imaging techniques that can better reveal the levels and
interactions of amino acids, neurotransmitters, and other physiological aspects
of the brain also would be of interest to those researching other
neurodegenerative diseases and in fields such as psychiatry and speech,
language, and hearing sciences.
Dydak has studied welders in China, where until recently the
amount of manganese exposure was less regulated. Dydak will use the grant to
continue developing imaging software and to observe study participants for the
long term. She also will be able to study U.S. welders.
“Since it is not known at what levels of exposure
manganese starts to have adverse effects, it also is important to study our
local welders, even if they work under well-regulated exposure
conditions,” Dydak says.
Dydak has shown in previous studies that manganese exposure
is related to an increase of the brain’s main inhibitory neurotransmitter,
gamma-aminobutyric acid, known as GABA. The increase occurs in a region of the
brain responsible for movement. She also found that young, healthy workers
exposed to manganese daily in the workplace had double the levels of GABA than
control subjects. The increase in GABA was accompanied by a decrease in levels
of N-acetylaspartate, which indicates decreased neural function. Her findings
were published in Environmental Health
Perspectives.
In the upcoming study, the brain chemistry and health of 48
workers with high and low exposure levels will be compared to 24 people who
aren’t exposed, 15 manganism patients, and 24 patients with Parkinson’s disease
not related to manganese exposure.
While the study’s human component focuses on noninvasive
diagnostic tools by MRI, the animal component will focus on new imaging options
in positron emission tomography (PET) scans to learn more about brain
chemistry. In this part of the study, Dydak will focus on changes of dopamine,
which helps the brain regulate movement.
“In Parkinson’s disease, it is known that the dopamine system
is compromised,” she says. “Using PET imaging and novel MRI
techniques at the same time allows us to pick up and analyze changes between dopamine
and GABA.”
