Primate Models Of Disease
Primates are ideal models because they have even greater homology than mice and they are extremely similar to humans in terms of their genetics, anatomical features and behavioural characteristics. But because primates are very much like humans, use of primates in research is fraught with ethical and moral considerations, thus any research conducted on primates has strict regulations which need to be adhered. In addition the cost associated with primate research is high, due to the special facilities required to handle primates. Because of cost issues researchers seldom use large sample sizes, which can also affect validity of the results, but they still feature in research because of the advantages associated with their use (Wekerle et al, 2006).
Primate models of multiple sclerosis
Multiple sclerosis (MS) is an autoimmune inflammatory disease that affects the central nervous system. It results in the demyelination of neurones in the brain and spinal cord. A definitive cause remains to be elucidated but research conducted utilising animal models of multiple sclerosis have advanced knowledge of this disease. Significant research has been found using rodents but research on primates is seen as more relevant due to anatomical similarities (Wekerle et al, 2006).
T- Cells are a key part of the immune system and are involved in identifying foreign material. In MS, it is thought that T-cells are unable to distinguish foreign material from self material. Research on Marmosets has identified that normal healthy T cells have the ability to develop encephalitogenic properties (Genain et a, 1994). The research group chose Marmosets because they are born as twins and thus have similar immunological tolerances, allowing for more valid observations to be made. Meinl et al, (1997) expanded on this work looking at myelin basic protein (MBP) specific T cells and their ability to causes encephalomyelitis. The research group used Rhesus monkey as their chosen primate model; they extracted MBP – specific T cells, activated them in vitro and injected them back into the monkey, they noted that roughly one third of the monkeys started to develop a mild CNS inflammation. This supports the theory that normal T- cells can generate encephalitogenic properties upon activation.
Primate models of autism
Autism is a condition, which is characterised by impaired communication and social skills, as well as obsessive behaviour. There is strong heritability with this condition. Research into autism has focused on trying to understand the neurobiological changes that occur in the brain of autism sufferer. Primates are considered as good models for autism because they have many similar anatomical features in their brain.
The diagnostic symptoms associated with autism can be regenerated in primates through social deprivation strategies (Hemby et al, 2001). Sanchez et al (1998) compared socially deprived monkeys (during rearing) to normal mother reared monkeys, to see what changes existed between them. They noted that the socially deprived monkeys generated symptoms associated with autism such as repetitive and abnormal behaviour. In addition these monkeys tended to alienate themselves socially. But no substantial changes were observed in the anatomy of the brain when examined through MRI. This adds impetus to the nurture side of the nature/nurture debate, which debates whether we are born with certain behavioural attributes or whether we just learn them. In the case of autism, this could possibly suggest that we can learn to become autistic, but the extrapolation of experiments using social deprivation strategies need to be considered carefully as these are not reflective of situations in which humans generate autism (Hemby et al, 2001). Moreover other autistic studies on primates have shown alterations in structures associated with the hippocampus and the temporal lobe can cause autism (Hemby et al, 2001).
