Researchers say black mold toxins could affect sense of smell

[Guest guest]

Researchers say black mold toxins could affect sense of smell

by Tom Oswald

http://msutoday.msu.edu/index.php3?article=03Mar2006-4

March 3, 2006 - MSU researchers in the Center for Integrative

Toxicology have found that certain toxins produced by black mold,

that ubiquitous fungus found everywhere from damp basements to

thousands of buildings in hurricane-ravaged New Orleans and the U.S.

Gulf coast, are capable of killing nerve cells, essential for the

sense of smell, that are located in the nasal passages of mice.

The scientific study – the first of its kind to investigate the

potential harmful effects of inhaling mold toxins on the nasal

passages – has been released on the prepublication Web site of the

scientific journal, Environmental Health Perspectives, at

www.ehponline.org It also will be presented by MSU researchers at

the Society of Toxicology annual meeting in San Diego in early

March.

" Essentially, this toxin is killing off the cells needed for the

sense of smell, " said Jack Harkema, a University Distinguished

Professor of pathobiology and diagnostic investigation and one of

the MSU researchers. " This is the first animal study to really show

that a toxin derived from the spores of black mold may cause

significant damage in the nose and the frontal part of the brain

involved in olfaction. "

According to the MSU researchers, these toxins found in black mold,

also known as Stachybotrys chartarum, specifically killed olfactory

sensory neurons in the nasal airways of exposed mice. These nasal

neuronal cells are known to detect odors and send electrical signals

to the parts of the brain that are necessary for the sense of smell,

or olfaction.

In addition, they found that the mice that inhaled these fungal

toxins developed rhinitis, inflammation of the nasal passages. Mild

inflammation also was detected in the animals' olfactory bulbs, the

part of the brain directly connected to the olfactory nerves from

the nose. Olfactory bulbs relay the smell signals from the nose to

other parts of the brain that are involved in olfaction.

" The mice used in the study were allowed to sniff a single small

dose of the toxin, which is known as satratoxin G, " said

Pestka, a professor of food science and human nutrition. " The amount

of toxin given to the mice would be close to estimated amounts that

a person, without respiratory protection, may inhale when working in

a room heavily contaminated with black mold. "

" In every mouse that received the single dose of satratoxin G, " said

Zahidul Islam, a research assistant professor in Pestka's

laboratory, " there was a large loss of olfactory sensory neurons

through a process called programmed cell death or apoptosis, and all

of these same mice also developed secondary inflammation in the nose

and olfactory bulbs of the brain. "

" This is the first report actually showing that olfactory neurons

undergo death when exposed to low levels of these toxins, " Harkema

said. " Can we extrapolate to humans? It's hard to say. But we do

know that olfactory cells that line the airways of mice are similar

to those in the human nose.

" Are our noses more or less sensitive to this toxin, and other

similar fungal toxins? This is really a crucial question yet to be

answered. We also need to develop better ways of detecting these

toxins in the contaminated air of water-damaged buildings, so that

we can protect the public from toxic exposure, " he said.

Exposure to black mold has been linked to another dangerous

respiratory disorder called pulmonary hemorrhage. A number of

infants in the Cleveland area who lived in mold-contaminated homes

were reported in the mid-1990s to have developed this lung disorder

and some even died as a result of this condition. This bleeding

disorder of the lungs appeared to be caused by something in the air

of the infants' home environments, most likely toxins produced by

Stachybotrys chartarum or similar fungi.

" Also, it has been reported that there are neurological conditions

in people who have inhabited mold-contaminated buildings or homes, "

Harkema said. " They've claimed to suffer from memory loss or other

neurological symptoms. As we all know, memory can be triggered by

what we smell. Our studies in mice suggest that airborne toxins from

mold may damage our ability to smell. "

A recent Institute of Medicine report said " critical gaps " exist in

the knowledge of the effects of black mold and its relationship to

what is known as " damp building syndrome. "

" What our laboratory research, and those of others, will do is allow

us to better understand the cellular mechanisms underlying the toxin

causing injury in the nose and brain, " Pestka said. " It is crucial,

however, that others also conduct well-designed human

epidemiological studies so that we can better determine the overall

human health impact of exposure to airborne toxins from black mold. "