A pill to treat the trisomic brain?
It is well known that people with Down Syndrome suffer some form of intellectual disability, usually in the mild to moderate range. Less clear is how healthcare professionals should treat this disability.
The picture below illustrates some of the effects of Trisomy 21 on the brain. Patients with Down Syndrome have trouble with memory, a function of the brain's hippocampus.
Can you imagine a pill that treats some of these brain defects caused by Down Syndrome? Well it may be coming sooner than you thought!
A recent scientific review published in Nature summarizes the different therapeutic approaches that scientists are currently investigating. Here are the three of the most promising new treatments for the cognitive impairment in patients with Down Syndrome:
1. Neurotransmitter replacement. A neurotransmitter is a chemical that transmit signals from a neuron to a target cell. Patients with Down Syndrome have deficiencies in important neurotransmitters. Tests on mice indicate that neurotransmitter replacement treatments are usually only effective on young trisomic mice, highlighting the importance of correctly timed treatment. However, it is not certain whether or not these therapies would also work for humans.
2. Targeting cellular mechanisms. People with Down Syndrome have fewer cells in the hippocampus, a component of the brain that plays an important role in memory. Therefore, scientists hypothesize that molecules that regulate neuronal plasticity might enhance cognition in patients with Down Syndrome.
3. Normalization of gene dosage. Other treatments focus on the normalizing the activity of genes linked to Down Syndrome. Trisomy can cause gene overdoses—or overexpression—which lead to the negative symptoms associated with the disorder. Treatments that attempt to normalize gene dosage essentially attempt to reduce the copy number of the genes from three to two.
Despite all these promising new treatments, many questions remain before they can be successfully used in human subjects. When and how long should a treatment be administered? To promote the proper development of the brain, could prenatal administration be feasible? On the other hand, could treatment be beneficial to patients with Down Syndrome that have dementia?
Furthermore, I wonder if these treatments might also have deleterious effects on patients. Therefore, I urge the scientists in charge of clinical trials to monitor all areas of the brain during treatment, not just the ones being targeted.
