Tiny but complex units of protein in the skin – called desmosomes from a
combination of Greek words – have been found to play an important role in
preventing allergic disorders. This discovery was made recently by an
international group of researchers, headed by Prof. Eli Sprecher at Tel Aviv
Sourasky Medical Center and Prof. Kathleen Green of Northwestern University in
Illinois, and was published in the prestigious journal Nature
In recent years, for unknown reasons there has been an increase
in the prevalence of allergies in general and specifically in the skin,
including atopic dermatitis (which is often called “asthma of the skin”). It had
been thought that immune system malfunction was the cause of the growing
problem. This notion resulted in numerous attempts to treat atopic dermatitis
through varied strategies – all aimed at weakening immune system activity at the
risk of often severe side effects that increased the risk of complications from
infections. But more recently, abnormalities in the body’s immune system have
been thought to occur in allergic diseases due to a primary defect inside the
This barrier is in fact a functional entity located in
the upper layers of the skin; it separates us from our environment and makes
sure essential nutrients and proteins are kept within the body, while unwanted
intruders, including allergens, are prevented from entering. The functionality
of the skin barrier has been shown to be dependent upon the presence within
human cells of several proteins, such as filaggrin – whose absence is considered
a major risk factor for atopic dermatitis.
Now, the international team of
researchers report that key to the proper function of the barrier are
desmosomes. Liat Samuelov, who co-headed the project with Ofer Sarig in Tel
Aviv, commented: “Desmosomes are responsible for ensuring cell-cell adhesion
within all layers of the skin. We found out that a critical component of the
desmososmes called desmoglein 1 is missing in the skin of patients affected by a
life-threatening form of allergic skin disease called SAM syndrome (Severe
dermatitis, Allergy, and Metabolic wasting).
Sarig added: “The disease is
caused by poorly functional bonds between cells located in the upper part of the
This is apparently enough for foreign proteins to move across the
skin barrier and elicit an exaggerated immune response. Even more interestingly,
when we studied isolated cells from the patients, these were found to secrete
numerous mediators of allergy.”
Their discovery thus questions the role
of the immune system in allergic processes, with clear implications for the
development of new treatments in atopic dermatitis, they
We all know about organ transplants – but stool
transplants to treat drug-resistant diarrhea in children? In its more extreme
form, recurrent diarrhea can cause life-threatening colon inflammation, which is
for some 14,000 deaths each year in the US alone, according to the country’s
Centers for Disease Control and Prevention.
In fact, according to
researchers at Johns Hopkins Children’s Center in Baltimore, the best hope yet
for an effective treatment of childhood infections with the drug-resistant
bacterium C. difficile may come straight from the gut.
Oliva-Hemker, director of pediatric gastroenterology there, is launching a fecal
transplantation program for patients with recurrent diarrhea. She says it is
caused by a “wily pathogen that is increasingly impervious to drugs and a
rapidly growing problem among children and adults.”
Over the past two
decades, cases of antibiotic-resistant diarrhea have more than doubled, with
nearly three million new infections each year, with up to a fourth of patients
not responding to antibiotics, research shows. Most such cases, the researchers
say, stemmed from infections with bacteria called C. difficile.
transplantation – or the transfer of ‘good’ bacteria from the colon of one
person into the colon of another – should be considered for all children with C.
difficile infections who don’t respond to two standard courses of antibiotics,”
said the Maryland researcher.
Studies in adults show that more than 90
percent of patients are cured following such therapy and, experts say, they have
every reason to believe the numbers would be equally impressive in
“Antibiotics are lifesavers, but any time we give them to a
patient to eradicate one pathogen, there’s collateral damage, in that along with
the bad bacteria we wipe off some good organisms that help keep the complex
workings of our gut in perfect balance,” Oliva-Hemker explained.
beneficial bacteria work by keeping rogue players in check, “so any shifts in
gut environment – such as ones caused by antibiotics — can have dire
When good bacteria are killed off by antibiotics, the bad
guys multiply causing an imbalance or “dysbiosis,” Oliva- Hemker said.
Typically, gut infections caused by one antibiotic are treated with another one
to eradicate the overgrowth of harmful pathogens, but drugs often fail to do so
fully or permanently because they only treat part of the problem.
we administer an antibiotic to treat the C. difficile infection, we destroy some
of the bad bacteria, but that does not address the other half of the problem —
the loss of good bacteria that might have led to the infection to begin with, so
we never truly restore the balance in the gut and often the diarrhea returns
with a vengeance in a matter of weeks,” added Dr. Suchitra Hourigan, a pediatric
gastroenterology fellow at Hopkins who has a special interest in fecal
The concept is hardly new. The method originated with
ancient Chinese healers who gave their diarrhea-ravaged patients “yellow soup,”
a concoction of fecal matter and water. Thousands of years later, the delivery
approach has evolved. Today, fecal transplants are often performed during a
colonoscopy, and improvement can be seen in as little as two weeks, as
beneficial bacteria start to repopulate the patient’s gut. Fecal donors, usually
parents or relatives, are carefully screened for risks much like any blood
donor, Hourigan says. The donor’s blood is tested for infectious pathogens, such
as HIV and hepatitis C. People with autoimmune diseases or other chronic
conditions, such diabetes or obesity, may not qualify as donors.
decade or so, Oliva-Hemker predicts, scientists would be able to design the
perfect fecal concoction in a lab, obviating the need for fecal
“In less than a decade, we’ll have lab-cooked poop that we
can administer to restore balance in the guts of people with a wide array of
conditions caused by the imbalance between good and bad germs.”
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