Pigs and dogs can bridge gap in research into drugs and regenerative
medicine
8 January 2009
Human and veterinary medicine could receive a big boost through the
use of larger animals, especially pigs and dogs, in research, says the
European Science Foundation.
It could bring drugs to the market more quickly at less cost, as well
as accelerating progress in other forms of therapy, notably the use of
stem cells in regenerative medicine.
The potential in this new field was discussed at a workshop organised
by the European Science Foundation (ESF) in September 2008. It called
for a European pig clinic to facilitate generation and characterisation
of models of human disease that would be funded within the EU's Seventh
Framework programme, the main source of EU funding for research
projects.
The immediate goal in the field is to establish a common standardised
way of using animals with clearly defined characteristics (phenotypes),
so that results can be compared across Europe. "The workshop showed that
there is excellent expertise in individual labs, but the phenotypic
tests need to be harmonised and standardised to facilitate comparison of
results obtained in different labs," said Angelika Schnieke, one of the
workshop's convenors, who holds the chair of Livestock Biotechnology at
the Centre of Life Science in Weihenstephan, Germany.
Such standardisation has already been achieved for rodents,
particularly the mouse, which is the most widely used animal model at
present for human disease research. The extension of such a framework to
pigs and dogs will bring great rewards not just for human medicine, but
also for treatment of animal diseases. "Large animals offer a link
between the classical rodent models and application in the clinic," said
Schnieke.
"In view of the close genetic, anatomical and physiological
similarities between dog and pig on the one side and human on the other,
large animal models are likely to catalyse drug development." As
Schnieke added, large animals would also help pursue other therapeutic
avenues beyond drug development, including new medical technologies,
devices and interventions.
Large animals could also be used for research in a number of disease
categories, including cancer, metabolic disorders such as obesity, and
regenerative therapies, such as use of stem cells to replace damaged
heart muscle.
The workshop focused particularly on pigs and dogs because these two
animals are quite similar in scale and anatomy to humans, while serving
quite complementary functions. Dogs could be used as models for studying
the immediate consequences of infectious disease, while pigs could be
genetically engineered to mimic certain human conditions, such as
deficiencies in the immune system.
In such cases pigs would be used like mice are at present to model
certain aspects of human immunity or metabolic disorder, but with the
advantage of being closer to us in many respects.
"A possible idea is the generation of pigs with a humanised immune
system," said Schnieke. "The proof of principle has been shown in the
mouse. Immune-deficient mice can be reconstituted with human immune
cells and can be used to study immune reactions, for example against
tissue xenografts (transplantation of tissue between species, such as
pig to human). In theory this could also be possible in pigs. Therefore
the generation of immune-deficient pigs is an important goal."
Further funding is required to develop suitable pig models, possibly
within a European pig clinic. The workshop also discussed setting up
smaller collaborative projects focussed on specific disease areas, with
a view to obtaining funding from the ESF. A task force was established
to pursue these goals.
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