The following news release is being issued by the University of
Cincinnati and is also being distributed by the U.S. Department of
Energy's Brookhaven National Laboratory. It describes a potential
strategy for treating cystic fibrosis (CF) - an inherited, fatal
disease that affects 30,000 Americans - by using slightly acidified
sodium nitrite, a common food preservative, to kill
antibiotic-resistant bacteria that thrive in the mucous-clogged lungs
of CF patients. The study, headed by Daniel Hassett at the University
of Cincinnati, is published in the February 2006 Journal of Clinical
Investigation. Brookhaven Lab chemist Sergei Lymar, one of the key
researchers on the 15 member research team, helped identify the
nitrite-derived species toxic to the bacteria. He also did computer
simulations of the anticipated chemical reactions and helped equip
Hassett's lab to work with nitric oxide. Lymar's work on the study was
funded by the Office of Basic Energy Sciences within the U.S.
Department of Energy's Office of Science.

Brookhaven Lab media contacts:

Karen McNulty Walsh
kmcnulty@bnl.gov
(631) 344-8350

Mona S. Rowe
mrowe@bnl.gov
(631) 344-5056

**********************************************
University of Cincinnati News Release

EMBARGOED FOR RELEASE
5 p.m. (EST), Thursday, Jan. 26, 2006

CONTACT: David Bracey
david.bracey@uc.edu
(513) 558-4559

NOTE TO EDITORS: Photos of Dr. Hassett are available by calling (513)
558-4559.

COMMON FOOD PRESERVATIVE MIGHT PROVIDE TREATMENT FOR CYSTIC FIBROSIS

CINCINNATI-Researchers led by a University of Cincinnati (UC) scientist
say they have discovered what might be the "Achilles' heel" of a
dangerous organism that lives in the lungs of cystic fibrosis
patients-a fatal flaw that leaves the organism vulnerable to
destruction by a common food preservative.

It has been known for some time that the bacterium, Pseudomonas
aeruginosa, grows within the deadly, lung-clogging mucous found in the
airways of cystic fibrosis patients and significantly weakens them.

The new study suggests, however, that a mutation-known as mucA-in the
organism also represents a fatal flaw that could help physicians clear
the characteristic "goop" from the lungs of advanced cystic fibrosis
patients.

The reason for optimism, the researchers say, is that the same genetic
change that turns Pseudomonas aeruginosa into a sticky,
antibiotic-resistant killer also leaves it susceptible to destruction
by slightly acidified sodium nitrite, a common chemical that is widely
used in the curing of lunch meat, sausages and bacon.

The finding is reported in the February 2006 edition of the Journal of
Clinical Investigation by a 15-member U.S. and Canadian team headed by
Daniel Hassett, PhD, an associate professor in UC's molecular genetics,
biochemistry and microbiology department. The research was funded by
the U.S. National Institutes of Health, the Cystic Fibrosis Foundation
and the U.S. Department of Energy.

"We believe that we have discovered the Achilles' heel of the
formidable mucoid form of Pseudomonas aeruginosa, which could lead to
improved treatment for cystic fibrosis airway disease," said Dr.
Hassett. "We can essentially say that this organism, which some people
thought could never be beaten, can now be destroyed by nothing more
exotic than a common food preservative."

Cystic fibrosis, which affects about 30,000 people in the United
States, mostly Caucasians of north European origin, is an inherited
disease caused by a defect in a gene called the cystic fibrosis
transmembrane conductance regulator (CFTR). Affecting the airways and
many other vital organs and processes, cystic fibrosis is chronic,
progressive and ultimately fatal, mostly as a result of respiratory
failure.

"The lung-clogging, suffocating mucoid form of Pseudomonas aeruginosa
essentially is a death sentence for cystic fibrosis patients because
these bacteria are inherently antibiotic and white-cell resistant,"
said Dr. Hassett.

Until the 1980s, most deaths from cystic fibrosis occurred in children
and teenagers. Today, thanks to improved treatments, people with cystic
fibrosis live an average of 35 years.
"During the chronic form of cystic fibrosis," Dr. Hassett said, "the
mutated form of the organism, combined with the immune system's
attempts to fight it off, wreaks havoc in the lungs.

"When Pseudomonas aeruginosa invades the mucous that's built up in the
airways," said Dr. Hassett, "it forms a resistant 'biofilm,' like that
which occurs on teeth or a toilet bowl, and divides rapidly.

"White cells from our immune system try to get in there to fight off
the invaders," he added, "but they can't reach the bacteria to kill
them because they're enmeshed in that thick mucous, essentially a human
form of 'quicksand.' So in trying to defend the body against the
Pseudomonas aeruginosa, the white blood cells end up dumping toxic,
damaging material onto the airway surfaces, which leads to lung
destruction.

"This biofilm lines the whole area, getting thicker and thicker and
developing into a dense layer that deprives surface tissue of oxygen,
ultimately killing it. So it's not only the bacteria that contribute to
the disease, it's also our own immune system."

The good news is that Dr. Hassett and his colleagues found that about
87 percent of the mucoid Pseudomonas organisms they studied have a
"fatal flaw" in the very gene (mucA) that makes it mucoid as well as
antibiotic and immune-system resistant-they are easily destroyed by
slightly acidified (pH 6.5) sodium nitrite.

Part of the problem with early and chronic cystic fibrosis, Dr. Hassett
explained, is that patients with these conditions make very little
nitric oxide, a derivative of acidified sodium nitrite.

"Mucoid Pseudomonas aeruginosa bacteria should have enzymes that are
able to dispose of both nitrite and nitric oxide," Dr. Hassett said,
"but for whatever reason, this particular bug doesn't make them, or has
very low levels of them.

"That's the fatal flaw in mucoid Pseudomonas aeruginosa."

Dr. Hassett and his colleagues had worked on the hypothesis that the
mucoid bacteria-because they flourish in patients who are essentially
drowning in their own airway mucous-would grow better using nitrate or
nitrite as an alternative to the missing oxygen. But when they tested
nonmucoid and mucoid forms, the nonmucoids grew with both nitrate and
nitrite without oxygen, while the mucoid organism grew only with
nitrate, yet died with nitrite.

The team took about 60 mucoid bacteria from six different clinics in
the United States and Canada and found that of all the strains that
were mucoid, the ones that had mucA mutations were all sensitive to
nitrite, and those that are notoriously antibiotic resistant were even
more sensitive.

"Sodium nitrite kills the mucoids, and if nonmucoids or other bacteria
are present in the airways, it inhibits their growth too," said Dr.
Hassett.

"When we add slightly acidified sodium nitrite to a suspension
containing mucoid bacteria, it's converted to the gas nitric oxide,"
said Dr. Hassett. "The mucoid bacteria can't dispose of the nitrite
metabolically, and also have difficulty handling the gas, so they die.

"Here was something we hypothesized that would allow mucoid bacteria to
grow much better than nonmucoid bacteria, but instead it killed them,"
said Dr. Hassett. "In plain English, these bacteria had a defect that
we didn't anticipate. I've never been so happy in my life to be wrong!"

Sodium nitrite, Dr. Hassett said, has potential as "a time-release"
capsule for cystic fibrosis patients. Because the nitrite is degraded
very slowly, and mucoid bacteria can't get rid of it, it should
specifically kill mucoid organisms that have the mucA mutation-which
most do.
Dr. Hassett said he envisions sodium nitrite could be used in aerosol
form to treat mucoid Pseudomonas aeruginosa in cystic fibrosis lung
disease.

"This wouldn't need to be a long-term treatment," he said. "Once a
patient acquires mucoids, which commonly occur, the physician would
simply use sodium nitrite and monitor how many mucoid bacteria are
still in airway sputum. Once the mucoid organisms are killed, and the
patient starts showing signs of improvement, treatment would continue
with conventional antibiotics."

But bringing this treatment to the bedside won't be easy, Dr. Hassett
conceded.
"Right now, we don't see the Food and Drug Administration approving
blowing sodium nitrite into people's airways, because it may
potentially have some toxic side effects.
"However, nitrites are used clinically, to counteract cyanide
poisoning, warts and athlete's foot, for example. And in neonatal
pulmonary hypertension, physicians may be using nitrite doses nearly 60
times higher than we use to kill the organism in mouse and human airway
cells."

Key researchers on the 15-member research team with Dr. Hassett were
San Sun Yoon, formerly with the University of Cincinnati and now at
Harvard Medical School, Sergei Lymar, Brookhaven National Laboratory,
and Richard Boucher, University of North Carolina.

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