By Janet Fang
Posting in Environment
Scientists show how early exposure to microbes has lasting effects on the immune system's sensitivity to allergies and asthma. Are all these antibiotics and antibacterials making us sicker?
Now researchers explain why that early encounter is good: it helps curb inflammation by altering the amount and function of immune cells.
The work also offers evidence for the ‘hygiene hypothesis,’ which proposes that the increase in asthma and other inflammatory diseases is due to our reduced exposure to microbes – thanks to antibiotics and antibacterials.
A team led by Harvard’s Dennis Kasper and Richard Blumberg show that bacterial communities help regulate quantities and functions of certain immune cells – called invariant natural killer T cells (iNKT) – in mice.
- Germ-free mice that were raised in sterile environments had higher amounts of iNKT cells in their colons and lungs.
- They were also more sensitive to asthma and more susceptible to colitis, an inflammation of the colon.
- Recolonizing these germ-free mice with different populations of bacteria lessened the symptoms of colitis and asthma, and also kept iNKT cell counts low.
- BUT this was only the case if mice were exposed to bacteria as newborn pups. Exposing adults to microbes didn’t reverse the inflammation – showing how early exposure to microbes has lasting effects on the immune system’s sensitivity to allergies and asthma.
Turns out, the germ-free mice also had an increase in the expression of CXCL16, a protein linked to inflammation. Nature News explains:
An analysis of the gene encoding CXCL16 showed that five regions of the gene were hyper-expressed in germ-free mice owing to DNA methylation – the tacking on of molecules to the DNA strand which can alter the production of particular proteins.
They concluded that, without exposure to certain microbes, methylation increases CXCL16 expression, which ultimately increases iNKT cell numbers and inflammation.
"These studies show the critical importance of proper immune conditioning by microbes during the earliest periods of life," Blumberg says in a news release. "Also now knowing a potential mechanism will allow scientists to potentially identify the microbial factors important in determining protection from allergic and autoimmune diseases later in life."
The study was published in Science last week.
[Via Nature News]
Image by lorijohernandez via Flickr
Mar 27, 2012
I believe in this method fully. my kids will run and play outside with the best of them! the more exposure to the outdoors and mud cakes and tree climbing the better!
The best way to introduce a child to a healthy immune system is to have the mother nurse her child rather than feed it formula. The mother's initial nursing is not so much milk as a dose of her immune system. If you really want your children to live long healthy lives, raise them within close proximity to horses. Long term statistical studies (60+ years) have indicated that being raised in close proximity to horses, where you breath, ingest, etc. horse poop dust results in a super pooper duper immune system. It goes like this: 1. Horse eats grass and always ends up with some dirt in it's mouth. 2. Dirt contains uncountable variety of bacteria, etc. 3. Bacteria passes through the horse without harming it, being broken down by it's digestive system. 4. Horse poops bacterial fragments, including outer membrane. 5. Horse poop is exposed to sunlight, where ultraviolet light breaks some fragments into smaller fragments. 6. Horse poop dries and becomes dust in the wind. Now you have a whole new meaning for your favorite song. 7. Dust gets in your eyes, nose, mouth and lungs, making it's way into your blood stream (naturally occurring vacination). 8. Your immune system does the rest.
I read elsewhere that the cleaner the environment in the home the more prevalent allergies become. The body's immune system is set to be vigilent and attack infections; if there are no infections then the immune system gets triggered by other things like peanuts and other things and the hyper reaction leads to rashes, asthma and autoimmune diseases.
I have always believed that kids should have eaten a pint of dirt by the time they are 5 years old. Kids raised on farms with animals have lower rates of asthma.
Posts like this are always welcome by this reader. Spot on observation. There is a doctor in the Boston area that has been using tape worms to treat Crohns. The worms restore needed bacteria to the body in a natural way with fewer side effects than shots or pills. He has shown that it is possible to over stanitze your life and trigger health issues.
I have read extensively on the introduction of various parasites to patients with various forms of inflammatory bowel disease. The worms especially and even most of the bacteria are not necessarily beneficial. Parasites in the colon stimulate an immune response at the celular level, wherein stem cells in the wall of the colon switch on DNA in the cell to be to make it different from other epithelial cells in that these cells produce abundant amounts of mucus. It was in fact the recognition of beneficial side affects of parasitic infections in patients suffering from inflammatory bowel disease that have lead to a more common (and approved by the medical community practice) of "fecal transplants", wherein a donor's feces go through a cleaning process before being introduced into the patient's digestive track. The use of parasitic worms is greatly frowned upon.
His work on Crohns grew out of some research he did on a stomach illness that swept Boston in the late 1800s just after a new water treatment system was put in place. The illness had many symptoms similar to Crohns except it hit almost 20,000 people in a week. A problem at the treatment plant poisoning the populous was the first guess, but that proved a dead end. Eventually the illness went away and was forgotten. Later research showed they had actually cleaned the water too fast. Beneficial bacteria were being filtered out. It took several weeks for their stomachs to adjust.