Critique of Non-Human Primate Research
Why the project of the Cambridge Primate Center in Behavioural
Neuroscience (CPCBN) is scientifically irrelevant.
Our board has been asked to comment on the scientific aspect
of the proposed CPCBN. The comment is based on the short release
from the U. of Cambridge, entitled "Details of the proposed
science" to take place at the CPCBN. According to this
release, basic and clinical research at the projected facility
should contribute to:
- the understanding of the link between behaviour and the
neuronal structure of the brain,
- the understanding of the link between this structure and
- the development of clinical diagnosis and therapeutic
the testing of drug treatment,
- the understanding of how existing therapies work.
Although not explicitly stated in the release, we suppose
that the primates are considered here as models of human behaviour
and pathologies. This is a frequent assumption, which is,
however, false. The very idea that one species can serve as
a model for a different species, demonstrates a complete lack
of understanding of fundamental principles of modern biology.
Any individual species is defined by its reproductive isolation,
which implies that its chromosomes (genome) cannot match,
complement or recombine with those of any other species. Hence
each species has a uniquely designed genome, i.e. the gene
structure, the control and regulation of gene expression etc.
are all strictly species-specific. Since the genes determine
all biological activities, it follows that the species' physiology,
its behaviour, its response to internal disorders (pathologies)
or to some external stimuli (e.g. toxins), are strictly species-specific
also. No species can therefore function as a biological model
for another species, no matter how closely related they are
This statement is especially valid in neurological matters.
Our central nervous system distinguishes us most dramatically
from that of any other known living species, including the
great apes. Therefore, using monkeys to predict the human
biological responses, in any of the five fields considered
by the CPCBN, is pointless. No result obtained from primate
studies can be seriously considered valid in humans as long
as the observation has not been made in man also. Hence the
preliminary primate experiment was useless. It can even be
counterproductive or dangerous, as it could pave the way to
false conclusions (remember the French blood scandal, a consequence
of the absence of reaction of chimpanzees to the AIDS agent
HIV, which led "experts" to OK the circulation of
HIV-contaminated blood samples). Many drugs, found efficient
and free of side-effects in primates, subsequently proved
to be lethal in man (the anticholesterol cerivastatin (Bayer)
is a recent example to point). Conversely, how many drugs,
perhaps very promising for human treatment, have been discarded
because they did not pass the monkey model?
Let us then briefly review the relevance of the five
scientific priorities assigned to the CPCBN.
- The brains of thousands of animals, especially monkeys,
have been explored since the 19th century to try to understand
how their behaviour is embedded in this organ. Libraries
are full of voluminous books detailing the very many studies.
Electrodes were placed in the brain to monitor its electric
activities, whilst keeping the animal awake for days, or
when removing the young from her mother just after birth,
etc. While the relevance to humans was already questionable
- and questioned - when these experiments were performed,
those results became almost overnight museum archives, when
non-invasive methods (PET-, NMR-scan...) enabled the investigation
of the human brain at work. Would the monkey show which
part of its brain is working when doing such basic human
activities as speaking, reading, writing, counting, singing?
Not to speak of evolved behavioural traits like reasoning
or sophisticated social attitudes. Today, no serious scientist
would go back to monkey models for such investigations.
- Human neuropathologies are at present of great concern
in industrialized countries. The very fact that they most
frequently occur in the last quarter of the human lifespan
proves that these conditions are age-related and occur in
humans at an age which exceeds by far the life expectancy
of even the great apes. So even if the latter were good
models for these pathologies - which remains to be proven,
since in the wild so far no monkey was found suffering from
these conditions - monkeys would not allow the study of
these pathologies, unless they were artificially provoked.
In a human individual these conditions almost invariably
have multiple causes, most of which will be missed in the
artificial pathology: again the animal model would be useless.
Chemical methods used to induce parkinsonism in chimps for
instance, were found almost 30 years ago, yet no understanding
of how the pathology develops in humans and how to treat
it permanently has emerged from the chimp model since.
- Clinical diagnosis and therapeutic strategies in monkeys
which have artificially acquired a given neuropathology,
are of no relevance to human patients, for the reason just
- The use of animal models to test the toxicity or effects
of drugs in human patients is highly problematic. In France,
the Health Ministry ascribes 20 000 fatalities a year due
to adverse drug reactions, in addition to 1.3 million hospitalizations,
despite the fact that the law requires that drugs be extensively
tested on animal models. Among the many reasons for this,
is the metabolism of the drug and drug-drug interactions,
both of which are strictly species-specific (because the
nuclear receptors of the drugs and the metabolizing enzymes
they control are species-specific).
- The project to try to understand how existing human therapies
work in animals which never develop the condition is somewhat
surprising. Wouldn't the money be spent better on more worthwhile
This critique was written by Dr Claude Reiss PhD.
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