Drugs attached to nanoparticles reduce the symptoms of Cerebral Palsy in rabbits if given soon after birth, by getting into the brain and targeting just the cells involved in the disease. This opens the door to treatments for a range of neuroinflammatory diseases including Alzheimer’s disease and multiple sclerosis.
Cerebral palsy is an umbrella term for a suite of disorders, all of which stem from an injury or insult to the developing brain and affect muscle coordination, cognition and sensory acuity. Once Cerebral Palsy is diagnosed, it’s usually too late to treat the brain injury itself, so current treatments concentrate on easing the symptoms.
It’s thought that two cell types are involved in the pathology of cerebral palsy – Microglia and astrocytes. Microglial cells are part of the immune system that police the brain and spinal cord, and in Cerebral palsy are thought to be the cause of inflammation. Astrocytes are essentially neuron support cells, but fail to protect nerve cells in situations of inflammation.
Writing in the journal Science Translational Medicine, Sujatha Kannan from Wayne State University and colleagues describe how these cells, normally protected by the blood-brain barrier, can be targeted by attaching drugs to branching nanomaterials known as dendrimers – which are already being investigated as a targeted delivery mechanism in cancer and other diseases. The drug they were using was NAC (N-acetyl-L-cysteine), a known antioxidant and anti-inflammatory agent which is also being tested as a treatment for Alzheimer’s and Autistic spectrum disorders.
The drug, linked to its dendrimers, was delivered to new-born rabbits that showed neuroinflammation and motor deficits, a good model of human cerebral palsy. A single dose led to a significant improvement in brain injury and motor function, whereas the drug without its nano-partner did not, suggesting that the dendrimers are key to getting the drug to where it’s needed.
This shows that there is a potential window for treating the brain injuries that lead to cerebral palsy, but we therefore need better ways of identifying those at risk early on. The authors argue that:
“Targeted therapy ... in at-risk patients, delivered at an early stage after birth, can potentially arrest or prevent the development of motor and cognitive deficits associated with perinatal brain injury and Cerebral Palsy.”
This is also a good test of nanoscale dendrimers as drug delivery agents, and gives us good reason to look forward to the results of other trails testing these in a wide range of diseases.