Single wall and multiwall carbon nanotubes, types of nanoparticles which caused changes in kidney cells in the study conducted by researchers from the schools of science and medicine at Indiana University-Purdue University Indianapolis. Image: Indiana University-Purdue University Idianapolis
A study by researchers from the schools of science and medicine
at Indiana University-Purdue University Indianapolis examines the effects of
carbon nanoparticles (CNPs) on living cells. This work is among the first to
study concentrations of these tiny particles that are low enough to mimic the
actual exposure of an ordinary individual.
The effects on the human body of exposure to CNPs—minute
chemicals with rapidly growing applications in electronics, medicine, and many
other fields—is just beginning to be revealed. Exposure at the level studied by
the IUPUI researchers is approximately equivalent to what might be the result
of improperly disposing of an item such as a television or computer monitor
containing CNPs, living near a CNP producing facility, or working with CNPs.
The research, published in Nanotoxicology,
focuses on the effect of low concentration CNP exposure on the cells that line
the renal nephron, a tubular structure inside the kidney that makes urine. The
investigators found the role of the CNPs in this part of the body to be
significant and potentially worrisome.
“Unlike many other studies, we have used low concentrations of
CNPs that are typical of what might appear in the body after ingesting them
from environmental contamination or even from breathing air with CNPs. We found
that these minute particles cause leakage in the cellular lining of the renal
nephron,” says study first author Bonnie Blazer-Yost, PhD, professor of biology
at the School of Science at IUPUI and adjunct professor
of cellular and integrative physiology and of anatomy and cell biology at the
IU School of Medicine.
“Breaching this biological barrier concerns us because things
that should be retained in the forming urine can leak back into the blood
stream and things in the blood can leak into the urine. Normal biological
substances as well as waste products are dangerous if they go where they are
not supposed to be,” Blazer-Yost says.
“These CNPs don’t kill cells—so they are not lethal, but they do
affect cells, and in this case it’s an adverse effect,” says corresponding and
senior author Frank Witzmann, PhD, professor of cellular and integrative
physiology and of biochemistry and molecular biology at the IU School of Medicine
and adjunct professor of biology at the School of Science.
Biological barriers are very important to human health. The most
well understood is the skin, but there are many others. “The human body needs
intact barriers, whether it be skin, airway linings, gut walls or the kidney
cells we looked at in this study. We need to gain a better understanding of how
CNPs modify and change characteristics of barriers as these tiny particles
become more common in the air we breathe,” says Witzmann.
The two researchers note that these incredibly strong particles,
visible only under an electron microscope, perform useful functions including
roles in drug delivery, and are responsible for many advances in electronics
such as the impressive colors seen on plasma televisions and computer monitors.
What they worry about is when CNPs enter the air and the environment and
eventually the human body from inappropriate disposal or from manufacture of
products containing the particles.
This study is part of the team’s larger body of work, which
looks at the effect of CNPs on barriers throughout the body including those of
the airways and large intestine.
“At this point, we know that CNPs have many beneficial
qualities, but also pose potential risks. These particles are so small that
when they get into various organs or systems they can bind to many things. We
need to further study what they look like in various parts of the body, how
they affect protein expression, as well as what they do when they cross a
barrier or are excreted,” says Witzmann.
“Studying the cellular alterations in the
urine-blood barrier in the kidney caused by repeated exposure to low
concentrations of CNPs is the initial step to understanding the assault on the
human body of accidental exposure to CNPs but it is an important one,” says