Could painkillers prevent recurring urinary tract infections?
An estimated 50% of all women will experience a urinary tractinfection at some point in their lives, and 20-40% of these
women will have recurring infections, putting them at risk for
kidney and bloodstream infections. But now, new research
suggests over-the-counter painkillers could help prevent such
infections from occurring.
Investigators from Washington University School of Medicine in
St. Louis, MO, presented their findings at the annual meeting
of the American Society for Microbiology.
They found that, by inhibiting an immune protein that causes
inflammation - called COX-2 - they were able to eliminate
repeat urinary tract infections in mice. The team explains that
COX-2 can be blocked by non-steroidal anti-inflammatory
drugs (NSAIDs), which includes ibuprofen.
According to the Centers for Disease Control and Prevention
(CDC), urinary tract infections (UTIs) are responsible for
around 4 million ambulatory-care visits every year in the US.
Most UTIs are caused by the bacterium Escherichia coli ,
which lives in the bowel. While men also get UTIs, women are
especially prone to them because their urethra is shorter -
which allows bacteria better access to the bladder - and a
woman's urethral opening is in proximity to bacteria sources
from the anus and vagina.
NSAIDs, such as ibuprofen, blocked a protein that causes
inflammation and significantly reduced vulnerability to repeat
UTIs.
Each time a woman has a UTI, her chances of having
recurrent infections increases, and severe infections with
sepsis can even be fatal.
In previous mouse studies, the researchers - led by Thomas
Hannan - found that the immune system overreacted to initial
infections, which suggested increased vulnerability to infections
that followed.
"We thought that the immune response was too weak in
patients who kept getting urinary tract infections," explains
Hannan, "but we are learning that an overly strong immune
response can be just as problematic."
He and his team found that immune cells, called neutrophils,
contribute to repeat infections in both women and mice. The
neutrophils leave tracks in the protective lining of the bladder
when they break in to fight infection, the researchers say.
Such damage could provide "footholds" that allow bacteria to
grab hold of the bladder lining and initiate severe infections.
COX- 2 inhibitors reduced susceptibility to repeat
infections
By manipulating the strength of the neutrophil response in
mice, so it was not too little or too much, the researchers
were able to wipe out UTIs without increasing the risk of
future infection.
They found that mice with increased susceptibility to recurring
infections had more inflammatory molecules in their bladder,
compared with mice that were not vulnerable to repeat
infections.
However, when such mice were treated with COX-2 inhibitors,
the team observed they showed a significantly reduced
vulnerability to repeat infections.
After examining the effect of COX-2 inhibitors on the immune
response in the bladder, the researchers found that while
neutrophils still entered the bladder in large numbers, they
caused significantly less damage to the protective lining.
As such, the team believes COX-2 inhibitors can selectively aim
for the adverse effects of inflammation while keeping the
beneficial responses.
Senior author Scott Hultgren, director of the Center for
Women's Infectious Disease Research at Washington University,
says their results are "encouraging," and that they "hope to
verify the potential benefits of COX-2 inhibitors soon in a large
clinical trial."
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