DOCTORS’ Notes
Something in the Water
To study how chemicals affect our brains and hearts, this lab uses see-through fish. BY MOLLIE RAPPE
F
ish may have fins instead of feet, but it turns out
they’re ideal models for studying how toxic chemicals
affect human brain and heart development.
Jessica Plavicki, PhD, an assistant professor of
pathology and laboratory medicine at Brown, uses zebrafish
embryos to study developmental genetics—how genes control
normal growth—and developmental toxicology—how environ-
mental factors interfere with normal growth and development.
For her research, she exposes the fish embryos to chemicals
found in water supplies to study their impact, such as perfluoro-
alkyl and polyfluoroalkyl substances (PFAS), a group of contami-
nants that includes byproducts from manufacturing nonstick
cookware and waterproof fabrics as well as residue from
firefighting foams.
“In my lab, we’re interested in understanding how exposure to
contaminants can impact the development of the brain and the
cardiovascular system,” Plavicki says. “And we’re really interested
in … the interaction between cardiovascular health and brain
health.”
Zebrafish are invaluable for biomedical research. They’re small,
social animals with embryos that develop quickly outside of their
mother and remain transparent for approximately a week.
Jess Plavicki looks
through the microscope
flanked by students and
fellows in her lab. From
left to right, Rachel Koch,
Nathan Martin, Cat Seitz,
Shannon Martin, and
April Rodd. Above, an
adult zebrafish.
6 HEALTH DISCOVERIES l WINTER 2020
“We can look under the microscope and watch them develop,”
Plavicki says. “We can look at blood flow. We can monitor cardiac
function in an embryonic fish. We can do functional neuroimag-
ing where we can look at changes in brain activity. Within the first
week, all the major organs come on line. It’s very rapid.”
Using a high-speed scanning confocal microscope, Plavicki and
her research team can watch how exposure to chemicals or
disrupted molecular pathways impact heart and brain develop-
ment in real time. A confocal microscope uses lasers to illuminate
tiny areas, which produces images and videos with much finer
detail than is possible with a traditional light microscope.
Among the topics they’re investigating is the effect of un- and
under-studied PFAS contaminants on nervous system develop-
ment and function. A recent scientific advisory committee
questioned whether the current guidelines for PFAS water
contamination levels were sufficient to protect human health.
“We don’t know which PFASs are really of health concern and
which ones aren’t,”
Plavicki says. “They
are a hot topic in
environmental
science right now.”