Researchers at the School of Medicine recently identified two molecules as potentially having a significant impact on future stroke treatment and recovery.

Mice that were genetically engineered to lack two immune system molecules or their corresponding cell receptor in the brain were better able to regain advanced motor functions following a stroke.

The molecules, “K” and “D,” and their cell receptor, PirB, are usually involved in regulating the brain’s ability to form and eliminate connections between neurons.

Researchers found that when performed in excess, the formation and elimination of brain synapses leads to a high risk for conditions such as epilepsy or schizophrenia.

The study, published March 22 in Neuron, showed that mice that were genetically engineered to lack either molecule or PirB, which is the receptor that molecules K and D bind to in order to carry out their function, experienced noticeably better motor performance recovery after the researchers induced strokes, compared to mice with normal levels of K, D and PirB.

Concentrations of molecules K and D increased drastically after the induced strokes, according to the results of the study.

The mice that were deficient in molecules K and D recovered advanced motor functions, such as traversing a horizontal ladder or spinning on a rod, significantly better than control mice and had smaller stroke-affected areas following the induced stroke. Results of the experiment with mice that lacked the cell receptor PirB mirrored the results for mice lacking molecules K and D.

The current treatment for strokes, tissue plasminogen activator (tPA), is only effective if administered within hours of a stroke and only acts to limit the damage of the stroke. tPA is also not capable of restoring or replacing the lost connections in the brain caused by the stroke.

The National Institutes of Health, the Mathers Charitable Foundation, the Ellison Foundation and the National Defense Science & Engineering Graduate Fellowship funded the study.

— Alice Phillips