MONDAY, Dec. 16, 2013 (HealthDay News) -- Researchers say
they've discovered why infants who live in homes with a dog are less likely to
develop asthma and allergies later in childhood.
The team conducted experiments with mice and found that exposing
them to dust from homes where dogs live triggered changes in the community of
microbes that live in the infant's gut and reduced immune system response to
common allergens.
The scientists also identified a specific species of gut
bacteria that's crucial in protecting the airways against allergens and viruses
that cause respiratory infections, according to the study published online Dec.
16 in the Proceedings of the National Academy of Sciences.
While these findings were made in mice, they're also likely to
explain why children who are exposed to dogs from the time they're born are
less likely to have allergies and asthma, the University of California, San
Francisco (UCSF) and University of Michigan researchers said.
These results also suggest that changes in the gut bacteria
community (gut microbiome) can affect immune function elsewhere in the body,
said study co-leader Susan Lynch, an associate professor in the
gastroenterology division at UCSF.
"The results of our study indicate that this is likely to
be one mechanism through which the environment influences immune responses in
early life," said Lynch in a UCSF news release. "It is something we
are currently examining using human samples in a large multi-institutional
collaborative study."
She said that it might be possible to use species of beneficial
gut bacteria to remodel people's gut microbiomes to prevent the development of
allergies or asthma, and even treat existing cases.
"Gut microbiome manipulation represents a promising new
therapeutic strategy to protect individuals against both pulmonary infection
and allergic airway disease," Lynch said.
Previously, the same research team found that dust in homes with
a dog that was allowed inside and outside had more diverse types of bacteria
and more species of bacteria that are found in people's gastrointestinal
tracts.
This isn't to say that new parents should rush out to buy a dog.
While the study found an association between the dogs and respiratory health in
mice, it didn't establish a cause-and-effect relationship. And results of
animal studies aren't always replicated in humans.