HEALTH MATTERS...mdr1
MDR1-/- THE SILENT KILLER
Liver failure, fading puppies, small litters, could
this gene mutation be responsible....????
Most people involved in our
Breed know and appreciate that some Collies are sensitive to certain Drugs, the
common thoughts with regard to this being that provided we stay clear of all
known ‘at risk’ drug, our Collies will carry on living long healthy normal
lives…simple.?
The problem was first
discovered quite by accident when researchers experimented on laboratory mice,
the mdr1 protein is one of the things separating mammals from insects and bugs,
and as such is present in all mammals including man. Researchers were
interested to learn what would happen (if anything) if this protein were
absent. To this end an experiment was set up and the mdr1 protein was removed
from a family of mice. For many months these mice lived an entirely normal
existence, eating, sleeping, mating and rearing their young, researchers began
to think the missing MDR1protein was making no difference at all to the lives
of these mice, until the mice developed a mite infestation. The cages were
sprayed with Ivermectin, the following day every mouse was dead.
Since this time we have
discovered many drugs fatal to collies carrying the double MDR1 gene mutation
(-/-).
For years I have kept a
private data base of collies having died of liver and kidney problems, having
experienced liver problems myself in the past, I wanted to know if other dogs
dying with these problems were related to those I had lost myself. Over the
years the data base grew and remained quite confusing, that is until we
discovered the MDR1 problem. As people began to make public the MDR1 status of
their dogs I began to notice a pattern emerging. The lines commonly found to
contain a large number of (-/-) dogs, were in fact often the same lines from
which the dogs in my data base were bred. More recently, some dogs have died
after having been tested for the MDR1 mutation, to press these have all been
-/- , food for thought!
Plus, when I discovered a line
free of liver problems, and included it into my breeding programme, not only
did I rid my dogs of liver problems, but when they were tested for MDR1, I
discovered they were +/+…in other words they were free of the mutation. This
could be coincidence, so I began research into what happens when the MDR1
protein is absent in humans.
It seemed common sense to me,
that if poisons and chemicals were crossing the blood brain barrier and
entering the brain, surely lesser toxins were doing this all the time but not
to an immediately fatal degree. As the MDR1 protein is responsible for pumping
these toxins away from the brain and out of the system, could these toxins be
remaining in the body and being stored in the liver? What about the toxins and
chemicals normally passed through the dogs’ body from complete diets, travel
sickness pills etc; were these being stored in body organs, building up over
time to create problems? If I was correct with my theory, the result would be
fabulous, It would mean the final solution is within our grasp to rid our breed
of some of the persistent liver and kidney related problems that have plagued
us.
My research into humans
revealed some interesting facts, one being that when the MDR1 P-glycoprotein is
absent, the placenta works differently. Poisons, lesser toxins and even some
viruses not only cross the blood brain barrier; they also cross the placenta
when they would not normally do so. Such humans often suffer with Colitis
too….ring any bells yet?
For a long time I wondered
how research into this gene mutation in Collies could be funded, my prayers
have been answered.
Steroids like Cortisol are
also transported by the P-glycoprotein (this is the protein that cannot be
produced by MDR1 -/- dogs) a new study has now been done in this area. One
thing quickly became apparent, In MDR1 -/- dogs there is a lower level of
Cortisol in the body, predisposing such dogs to greater problems when under
stress. It would appear that MDR1 dogs really do suffer more stress and stress
related illnesses. Other revelations presented by Professor Dr. Geyer of the University are, the placenta works
differently when the bitch is MDR1 -/-….and yes, toxins, viruses and chemicals
do cross the placental barrier in bitches and not only humans. There are now at
least 100 substances known to be dangerous to the MDR1 double mutant dog, and
the list is growing. The fact that such dogs have a huge improvement in health
when fed a natural raw meat diet emphasises the possible problems with toxin
overload when fed a modern complete diet. In MDR1 -/- dogs, antibiotics are far
more dangerous. Most people never consider antibiotics to be poisonous…but they
ARE…they are designed to poison bacteria.
Certain
Antibiotics can destroy the liver of a double mutant dog within days..!!!! If
your dog is in this category, and needs such medication, ask your vet to do
blood tests at regular intervals throughout the treatment to ensure no irreversible
damage is being done. Antibiotics or Steroids should NOT continue more than one
week, and if they must, blood tests must also be done. Many Breeders presently
have a policy of giving antibiotics randomly to bitches when mated, in light of
this latest research…is this really wise? Could this be one of the reasons some
bitches are dying of liver failure shortly after whelping and could it
responsible for ever decreasing litter sizes? Unless you know the status of
your bitch, you could be poisoning her and possibly her puppies too!
MDR1 protein
begins working when food or medicines enter the stomach. Many things are
transported out when the dog is MDR1 +/+, but when the dog is MDR1 -/- the entire dosage enters the blood stream,
where it is transported not only directly to the brain, but to every other
organ of the body. They enter organ cells and the placenta of developing embryo
where they remain for far too long.
Another big
problem revealed itself. If an MDR1 -/- dog is given a cocktail of anaesthesia
AND antibiotics together, it can totally
destroy the liver…! When a bitch is spayed, such procedure is normal, how
many collie bitches have died or been diagnosed with liver failure within a
short time of being spayed?
In the past we
knew nothing about the MDR1 P-glycoprotein, but now we do. In my opinion it is
the single most important problem within our Breed, but the good news is WE CAN
BREED IT OUT. Unlike CEA (in the
Perhaps we could begin
by testing our dogs, and making those results known to all fellow breeders. Perhaps
if our stud dog is -/- we should refuse bitches to him unless they are +/+ Likewise
if your bitch is -/-, wouldn’t it be wise to find her a partner who is +/+?
Perhaps the next
time you have a litter of puppies born and are debating which to keep because
you particularly like two bitches…have them MDR1 checked and let the result
decide. Slowly we can move forward.
I owned my first
show collie in 1974; I began studying the Breed in 1972. Rough collies have
brought so much joy into my life. We live in exciting times; we live in a time
when we can give something back to the Breed. In my opinion the missing MDR1 P-glycoprotein
is the silent killer, being aware of every dogs status is one step closer to
life.
The following
links are recommended.
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1636591
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1636591&rendertype=table&id=t1-cvj47pg1165
http://www.vetmed.wsu.edu/depts-VCPL/genetics.aspx
http://www.vetmed.uni-giessen.de/pharmtox/juniorprof/research.php#res_02
http://www.scielo.br/scielo.php?pid=S0103-84782006000100056&script=sci_arttext
Angela Harvey.
(Wicani Collies)
