A protein named GM-CSF used to treat Alzheimer's disease improves cognitive function in mice with Down syndrome (DS). The corresponding research was conducted by a team of scientists at the University of Colorado Anschutz Medical Campus and published in the journal Neurobiology of Disease.
GM-CSF is a natural human protein that has been used safely and effectively for over 30 years under the drug name 'sargramostim'. Studies have shown that GM-CSF improves neurological symptoms associated with Alzheimer's disease (AD).
People with DS are at higher risk for AD, with most developing symptoms of dementia by age 60. The current study examines if GM-CSF could be repurposed to treat the neurological symptoms in DS that precede dementia.
The researchers used a mouse model of DS to run their experiment. They gave the treatment to a group of mice with DS and a healthy group, while a control group was given saline. The mice underwent learning and memory tests, such as solving mazes, before and after treatment.
The researchers found that the drug had pro-inflammatory and anti-inflammatory properties and that it helped regulate the immune system. It also improved learning and memory deficits and helped to regenerate certain nerve cells in the mice with DS, as well as improve cognition in mice without the illness.
The results are unexpected as GM-CSF has pro-inflammatory properties, say the researchers. This challenges the theory that symptoms of AD and DS may be due to chronic inflammation and indicates that further research into the mechanisms of neurological decline in these conditions is necessary.
The researchers noted some limitations to the study. The exact mechanism by which GM-CSF improves the cognitive function of the mice could not be determined due to the complex and not yet understood effects of the compound on the immune and nervous systems. Furthermore, DS in mice presents differently from in humans, so the results may not translate over.
The results nevertheless indicate that "sargramostim should be tested for safety, tolerability, and efficacy for improving cognition in people with Down syndrome", write the researchers.
Scientists at CU Medical Campus and Colorado State University are currently researching the drug's potential to treat young adults with DS regarding cognitive function, quality of life measures, and biomarkers associated with neuronal damage.