Pet dogs could cut asthma and allergy risk


  • Microbes in mouse’s gut changed when exposed to dust from households that have domestic dogs
  • One such bacteria reduces inflammation of airways, which causes asthma
  • ‘Good bacteria’ may one day be used to prevent symptons, experts said

By
Daily Mail Reporter

17:24 EST, 17 December 2013

|

17:43 EST, 17 December 2013

Children’s risk of developing allergies – such as asthma – is reduced by having a pet dog as dust from an animal-friendly home changes the gut’s microbes, research shows (library image)

A pet dog could prevent children from developing allergies and even asthma, according to new research.

Children’s risk for developing allergies
and asthma is reduced when they are exposed at a young age to a dog in
the household and now researchers have discovered a reason why.

Mice that are exposed to dogs have different gut microbes and react less strongly to allergens, experts said.

One of these gut bacteria, called Lactobacillus johnsonii, helps to reduce inflammation of the airways, which is tied to asthma, they found.

The results were obtained in studies of mice challenged with allergens after earlier exposure to dust from homes with dogs.

The results also are likely to explain the reduced allergy risk among children raised with dogs from birth, according to the study leaders.

In their study the scientists from the University of California exposed mice to cockroach or protein allergens.

They discovered that asthma-associated inflammatory responses in the lungs were greatly reduced in mice previously exposed to dog-associated dust, in comparison to mice that were exposed to dust from homes without pets or mice not exposed to any dust.

Among the bacterial species in the gut of these protected mice, the researchers homed in on one, Lactobacillus johnsonii.

When they fed it alone to mice, they found it could prevent airway inflammation due to allergens or even respiratory infection. Severe RSV infection in infancy is associated with elevated asthma risk.

The researchers showed in this experiment that protection of the lungs’ airways was associated with reduced numbers and activity of asthma-associated immune cells.

Study co-author Professor Susan Lynch, from the University of California at San Francisco, said the level of protection with this single species was less than that obtained with the full complement of dust microbes from dog owners’ homes, indicating that other, environmentally sourced bacterial species probably are necessary for full airway protection.

She said this result suggests that Lactobacillus johnsonii or other species of ‘good’ bacteria might one day be used to reshape the gut in ways that can prevent the development of asthma or allergies, or perhaps even to treat existing cases.

One gut bacteria, Lactobacillus johnsonii, found in mice exposed to dust from a dog-friendly home helps reduce inflammation of the airways, which is tied to asthma (library image)

Lynch’s own work and research by several others in the field has led her to become convinced that ‘the composition and function of the gut strongly influence immune reactions and present a novel avenue for development of therapeutics for both allergic asthma and a range of other diseases.’

The current study demonstrates that changes in the gut can have wide-reaching effects on immune function beyond the gut, at sites elsewhere in the body, Lynch said.

The team had previously demonstrated that the presence of a dog that roams both inside and outside was associated with a significantly more diverse house dust microbes that was enriched for species found in the gastrointestinal tract of humans.

Professor Lynch said: ‘We set out to investigate whether being exposed to a distinct house dust microbe associated with indoor/outdoor dogs mediated a protective effect through manipulation of the gut and, by extension, the host immune response.’

‘The results of our study indicate that this is likely to be one mechanism through which the environment influences immune responses in early life, and it is something we are currently examining using human samples.’

The study is published online in the Proceedings of the National Academy of Sciences.

 

Comments (8)

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Renee Hollister,

San Diego Ca., United States,

2 hours ago

Many of my kin grew up living on farms. They are around cows, sheep, goats, pigs, turkeys and chickens of course the barn cats and their many dogs. None of them have allergies. But the part of the blood line who grew up in the city.. you name the allergy, we have one kind or another sometimes two or three. Crazy as it may seem, I think we should have visited our uncles, aunts and cousins at their farms more often. They are super healthy and the guys are really buff, they work their tails off and it shows. No need for them to work out at a health club, each and every day farm life is one heck of a work out and they are thriving!!

Jennybea,

New York City,

4 hours ago

I’m sorry- but what a crock. My husband grew up with Westies, as his parents breed and show them. There were anywhere between 5 and 10 dogs in the house at any given time- plus puppies. He was around them his entire life and he is very asthmatic. Dogs are awesome- we love them- and he loves the Westies- which his parents are still breeding. But he totally has allergies and asthma, and the dogs made not one bit of difference.

AuntyAlias,

San Francisco, United States,

5 hours ago

Holy smokes! My father told me this decades ago and I dismissed it as an old wives tale. Sorry Dad.

New Mexico,

New Mexico, United States,

5 hours ago

My daughter grand-daughter live with my mother. Long story. Anyway, my mother is practically OCD when it comes to housekeeping and waayyy over protective. She actually has a book that she’s using to raise my grand-daughter (My daughter doesn’t get a say, apparently.) Looggg story. AND, now my grand-daughter is allegedly allergic to practically everything.

Harry,

Bedford,

7 hours ago

Hygiene hypothesis, plus the fact that dogs are awesome

Aristotle314,

Provo,

11 hours ago

It isn’t the dust the dogs carry in from outside, it is their outdoor exposure to intestinal parasites that they then pass on to their human companions and any other mammals with close contact. There have been many research studies confirming that these intestinal parasites down regulate our immune systems and prevent autoimmune diseases like asthma, MS, diabetes type 1, and even autism. Do some research.

New Mexico,

New Mexico, United States,

5 hours ago

Wish my mother would. Ugh.

illbjammin,

Pasadena California, United States,

19 hours ago

Dogs rule!

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