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SCIENTIFIC CRITIQUE - Proposed primate experiments
Posted 1 August 2001
A submission by Animal Aid.
The very scientific validity of the proposed centre is open to question and should be subject to broad consultation and intense scientific scrutiny before any claims of such research being in the public interest are heeded.
The basic premise of the proposed science is that "how specific brain systems work normally to produce behaviour and also how they may malfunction in neuropsychiatric or neurological disorders" is the same in human and non-human primates; so that results from research in monkeys can be extrapolated to the therapeutic benefit of human patients. This is not the case, however.
Animal "models" of such complex and multifactorial conditions as Alzheimer's, Parkinson's, or Huntington's Disease, stroke, depression and other psychiatric disorders bear little relation to the real diseases in humans. They fail to reflect the complexities and idiosyncrasies of the human brain as well as failing to mimic the progression of the symptoms as they evolve over several years in patients. For example, marmosets are much used in research into Parkinson's Disease although their brains do not even develop Lewy bodies; a generally recognised marker for the disease in humans.
In fact, recent experiments at Cambridge University, purported to be furthering stroke research, revealed the gulf between the reality of human stroke patients and their marmoset "model" counterparts: the monkeys were able to run, climb, swing and jump almost as normal just three weeks after their artificially-induced "stroke". Yet the experiment was undertaken in marmosets , according to the researchers, because "it is inherently difficult to extrapolate the findings from rodent studies." This experiment clearly shows the inherent absurdity of extrapolating the results from marmosets to man.
In recent "Huntington's Disease research" at Cambridge University, the researchers admitted that their brain-damaged marmosets "did not replicate the symptoms or pathology of Huntington's Disease." Indeed, as with research into Alzheimer's and Parkinson's Diseases, these artificially created "models" will not reveal why the brain cells die, and will therefore not contribute to stopping the disease process.
It is human-based observations that have established the biochemical bases of these neurological illnesses and that will provide targets for possible therapies in the future.
In recent research in marmosets at Guy's, King's and St. Thomas' School of Biomedical Sciences in London, the researchers were surprised to find some Parkinson's drugs elicited reactions opposite to those produced in rats, and unable to explain why.
In order to avoid conflicting results between different species; a seemingly inexplicable problem confronting researchers in almost all recently published experiments attempting to compare brain function between humans and experimental animals; the studies must necessarily be conducted in donated human brain tissue (from operations or post mortem) or non-invasively (using scanners) in patients or in healthy volunteers.
The Humane Research Trust, for example, funds studies at the Cambridge Brain Bank at Addenbrooke's Hospital, using tissue cultured from patients undergoing surgery or who have died but wanted to help research into the condition from which they suffered.
Functional MRI scanners can monitor the brain activity of volunteers as they undertake tests of memory and other skills, to reveal brain areas that are active during particular activities. Transcranial magnetic stimulation (TMS) is a new technique which temporarily disrupts the functioning of the brain, allowing scientists to assess the impact of "switching off" specific regions without permanently removing them. The Dr Hadwen Trust for Humane Research is funding such studies at Oxford University. There are many additional state-of-the-art imaging techniques now available, including PET (positron emission topography), CAT (computer-aided tomography), MEG (magnetoencephalography), EROS (event-related optical signals). These sophisticated techniques are of immense value when used to study humans, but their expense cannot be justified for studying primates from whom the data obtained will not be applicable to humans.
An objective reading of recent experiments aimed at studying brain function in primates at UK universities including Oxford and Cambridge demonstrates that the only way to ascertain which brain regions are involved in specific human thought processes and abilities is to study the human brain. Results from the brains of any other species are simply misleading and can result in ineffective or dangerous therapies for humans.
Indeed, the authors of a recent "stroke" experiment on cats and monkeys at Guy's, King's and St. Thomas' Hospitals School of Medicine, London, concluded that it is not surprising that clinical trials of stroke medications based on animal models were unsuccessful because of the differences between human and animal brain function. The record of animal experiments in predicting useful treatments for stroke patients is abysmal, in fact. According to researchers at the Mayo Clinic, "over-reliance upon such animal models may impede rather than advance progress in the treatment of this disease."
Animal "models" are equally damaging in other spheres of research and medicine. The inventor of the polio vaccine, Dr. Albert Sabin, stated that the vaccine was "long delayed by the erroneous conception of the nature of the human disease, based on misleading experimental models in monkeys." Dr. Mark Feinberg, a leading AIDS researcher, said in 1997: "What good does it do you to test something in a monkey? You find five or six years from now that it works in the monkey, and then you test it in humans and you realise that humans behave totally differently from monkeys, so you've wasted five years."
There is, unfortunately, no shortage of human accident victims or patients with neurological illnesses, who are obviously the ideal subjects for research into their respective conditions, with, of course, their full and informed consent. Yet this most valuable of resources is neglected and under-funded while huge sums are allocated to spurious research in animals which will not benefit and may even harm the very patients it is claimed to be serving.
Permission for this proposed "Centre for Neuroscience" should be refused, in the national interest, and the funding should be re-allocated to clinical research in hospital and university departments and such valuable but underfunded institutions as brain banks and other human tissue banks.