THURSDAY, June 20 (HealthDay News) -- Estrogen treatment
delivered vaginally may help prevent repeat urinary tract
infections in postmenopausal women, new laboratory research
Urinary tract infections are common among women, with
one-quarter experiencing recurring infections. And age-related
changes increase the likelihood of these infections developing
after menopause, when estrogen production plummets.
Until now, taking antibiotics prophylactically -- to ward off
recurrent urinary tract infections -- has been the gold standard
for these women, said Thomas Hannan, a research instructor in
pathology and immunology at Washington University School of
Medicine in St. Louis. "But antibiotic resistance is increasing,
and some women are resistant to everything we have," Hannan said.
"We need other options. We need non-antibiotic options."
This study, published in the June 19 issue of the journal
Science Translational Medicine, "suggests a more holistic
approach by changing the way women respond to bacteria," said
Hannan, co-author of an editorial accompanying the study in the
The results support the use of vaginal estrogen as a preventive
measure for postmenopausal women with recurrent urinary tract
infections, he wrote in the editorial.
Working in the laboratory and with animal models, the
researchers identified a number of ways that estrogen -- the female
sex hormone -- helps keep recurrent urinary tract infections at
"This study presents some underlying mechanisms for the
beneficial effect of [topical estrogen formulations] after
menopause and supports the application of estrogen in
postmenopausal women suffering from recurrent UTIs," wrote the
study's authors, from the Karolinska Institute in Stockholm,
About half of all women will experience at least one urinary
tract infection in their lifetime, according to the study. For
about 25 percent of these women, the infection will come back again
within six months.
Low estrogen levels have previously been linked to recurrent
infections, and the new study sought to identify exactly how
estrogen might affect a woman's risk of recurrent urinary tract
For the study, the researchers used human cells from
postmenopausal women who had used supplemental vaginal estrogen for
two weeks. They also worked with mice that were given bacteria that
would cause urinary tract infections like those in humans.
They found that estrogen encourages production of natural
antimicrobial substances in the bladder. The hormone also makes the
urinary tract tissue stronger by closing the gaps between cells
that line the bladder. By gluing these gaps together, estrogen
makes it harder for bacteria to penetrate the deeper layers of the
bladder wall, the study authors said.
Estrogen also helps prevent too many cells from shedding from
the top layers of the bladder wall.
"Normally, there's an innate response to infection and some
cells die -- sort of taking one for the team -- and then these
cells shed," Hannan said. "But shedding too much could allow
bacteria to get into the deeper tissue, so this exfoliation is a
According to the study, estrogen promotes the redistribution of
cells and prevents excessive loss of cells during an infection.
One expert welcomed the findings.
"This study gives us more information about what we always had a
sense was true: that women do get more [urinary tract infections]
after menopause," said Dr. Jennifer Wu, an obstetrician and
gynecologist at Lenox Hill Hospital in New York City.
Although taking estrogen in pill form is associated with an
increased risk of breast cancer and cardiovascular disease, topical
estrogen is much safer, Wu said. Topical estrogen formulations
include creams, gels and vaginal suppositories.
"Only about 1 percent of estrogen cream or other topical
delivery gets into the rest of the body's systems," she said.
Although commonplace, women shouldn't accept recurrent urinary
tract infections as a normal part of aging, Wu said. "Talk to a
gynecologist or urologist to find out what kinds of therapies are
available," she said. "There are treatments besides
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