Neurotoxicologist to discuss perils of nasal passages

Thursday, November 17, 2005

Vulnerability of the brain from exposure to poisons through the nasal passages will be the subject of a lecture Friday, Nov. 18, at the OSU Center for Veterinary Health Sciences.

Dr. David C. Dorman, division director of biological sciences at the Chemical Industry Institute for Toxicology, will give the 2005 Sitlington Lecture in Toxicology at 2 p.m. in McElroy Hall. Now in its sixth year, the lecture series was started by Dr. Carey Pope, professor and Sitlington Chair in toxicology in OSU’s College of Veterinary Medicine, to promote the visibility of research in toxicology, the scientific study of the adverse effects of chemicals on living systems including cells, organisms and ecosystems.

Dorman’s presentation, “The Holes in Your Nose: Why Nasal Toxicology Matters,” will detail ongoing biomedical research to determine how ubiquitous toxicants, including heavy metals as well as emerging nano-materials, may reach the brain and elicit toxic effects via the nose.

“Heavy metals are a classic toxicant, and most people understand that exposure to lead, mercury and cadmium can have toxic consequences,” Pope said. “Dr. Dorman has shown that some of these heavy metals can actually be transported into the brain through the olfactory nerves that extend from the central nervous system into the nose.”

Pope said Dorman’s findings describe a novel manner in which the brain may be exposed to toxicants. Unlike lipid-soluble chemicals, heavy metals and other chemically charged, or water-soluble, compounds can be blocked from the brain by the blood-brain barrier.

“Chemicals that are very lipid soluble will go into the brain easily because they can pass through cell membranes lining blood vessels that comprise the blood-brain barrier,” Pope said. “Most pesticides we study pass easily into the brain because they are lipid soluble.

“However, chemicals that are charged, such as heavy metals, have a more difficult time getting into the brain. Dr. Dorman’s work on transport of some heavy metals through the olfactory tracts demonstrated it is possible for some toxicants to get around the blood-brain barrier, and it’s presently unclear how many other types of chemicals may be able to be transported into the brain through this route. It’s interesting to consider this alternative way of possible exposure to neurotoxicants, as the types of effects they may have and how far these chemicals may distribute once they get into the brain are currently unclear.”

In addition to heavy metals, Dorman will discuss his studies on a common air pollutant: hydrogen sulfide. He is also interested in emerging nano-materials, an emphasis shared by Pope and other toxicology researchers in OSU’s physiological sciences department, collaborating with Dr. Wei Chen and other colleagues at Nomadics Inc.

“Around the world, nano-materials are being manufactured with an array of chemical substituents, including heavy metals,” Pope said. “It has been reported that by 2015, $ 1 trillion of our economy could be generated by applications of these types of nano-materials.”

“At the same time, very little is known about the toxic potential of nano-materials in either environmental or human health. Our current research is focused on learning the toxic potential of some heavy metal-containing nano-materials in cells and whole animal models.”

In addition to his post at the CIIT in Research Triangle Park, North Carolina, Dorman is an adjunct professor of toxicology, physiological sciences and radiology at North Carolina State University’s College of Veterinary Medicine. Before this presentation, visitors can meet Dorman from 1-2 p.m. in the Alumni Conference room in McElroy Hall.

The OSU Center for Veterinary Health Sciences’ Sitlington Lecture series is supported by the Sitlington endowment, the OSU Foundation, and the College of Veterinary Medicine’s Office of Research and Graduate Studies.