*
Interest of the canine models in hereditary myopathies
*
Characterization of hereditary myopathies
*
Research of therapeutic processes
* Development of tools of
functional evaluations
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INTEREST
OF THE CANINE MODELS IN HEREDITARY MYOPATHIES
First specie domesticated by human, the dog has undergone a huge
pressure
of selection during the centuries. The genetic crosses,
performed by humans
to create races responding to various requirements (hunting, guarding,
people
assistance, etc), has produced a diversity that no
other mammalian
species offers. Unfortunately, this selection based on morphological or
behavioral attributes was accompanied by the selection of defective
genes
responsible for several genetic diseases among
which are myopathies.
The
canine
myopathies are often quasi perfect
replications of the human diseases. For example, the golden
retriever
muscular dystrophy (GRMD) is a homologous disease to the Duchenne
muscular
dystrophy. The GRMD dogs carry, like human patients, mutations in the
dystrophin gene. From the clinical and the histological point of view,
they
display important locomotive affections, respiratory and cardiac
failures, necrotic
lesions and fibrosis similar to those observed in human. These
strong
phenotypic and genetics homologies between human and canine patients
underline
the relevance of the dog as study model.
In
addition,
there are significant advantages to involve canine models in the
research on
myopathies, and especially at a preclinical level. First, to be efficient, a treatment against
myopathy needs to reach all dystrophic
muscles. The analysis of the bio-distribution of the administrated
medication
is thus an unavoidable preclinical step. On this aspect, dogs, with a
size
equivalent to a sick child, constitute an appropriate model. Next, they
allow a reliable and quantified evaluation of motor functions, contrary
to mice which badly reproduce symptomatic tables of human myopathies.
Finally, it
is easy to follow the global physiology in dogs. Indeed,
clinical
examinations and specialized complementary examinations
(echo-cardiographic
exams for example) are available in this specie.
However,
the
dog is a recent model;
the research tools available in
this specie are relatively scarce. Moreover, it is an extremely delicate
model
requiring a specialized structure and permanent veterinary cares.
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