A research team from the UCSF (University of California, San Francisco), in the United States, has revealed a new method to control the seizures of mouse models with epilepsy. Their study was recently published in the journal Nature Neuroscience. The method consists of a one-time implantation of MGE (medial ganglionic eminence) cells, responsible for the signal inhibition of the overactive nervous system. During precedent studies, researchers used several different types of cells but failed to stop the seizures.
Due to the limitations of current epilepsy medication, cell therapy became one of the most active fields of research. The leader of the study, professor Scott Baraban, affirms that current medication is only effective against the symptoms of the disease, and doesn’t address the causes. In addition, Baraban said that for most types of epilepsy, the currently available drugs have little to no therapeutic effect, whilst adding that “Our results are an encouraging step toward using inhibitory neurons for cell transplantation in adults with severe forms of epilepsy”. The findings of the current study are the first to report the stopping of seizures in mouse models with epilepsy.
The extreme muscle twitches and contractions that appear during seizures are responsible for the loss of control for some patients, thus causing them to fall and injure themselves. The abnormality responsible for these symptoms are considered to be the overactive nervous cells that react at the same time. The research team from UCSF transplanted cells which are capable of inhibiting these overactive nervous cells, thus reducing the total number of seizures in half of the mouse models and totally eliminating the seizures in the other half of the studied mice. Most of the key experiments were conducted by postdoctoral fellow Robert Hunt, who reported that prior to their current study, the research team discovered a method capable of producing human MGE-like cells in laboratory conditions.
Previous studies have shown that in most forms of epilepsy, the loss of inhibitory nerve cells within the hippocampus plays a key role in the evolution of the disease. The medial ganglionic eminence cells are precursor cells which are able to generate interneurons. These are mature nerve cells with inhibitory capacity. Researchers discovered that these transplanted cells integrate into the already existing nervous circuits.
The mouse model used by the researchers resembles a sever form of human epilepsy which is resistant to drugs, called mesial temporal lobe epilepsy. This particular form of epilepsy is believed to have its roots in the hippocampus. Researchers also tried to implant these cells into the amygdala, a region of the brain responsible for emotions and memories, however, this showed no results. The form of epilepsy studied in the current paper usually appears in adolescence, sometimes after a long period of time from the first seizure, which is most often caused by high fever. In mice, this was achieved through chemical exposure and is very similar to the human form. The main author of the study also notes that the mouse models which were treated with the aforementioned technique revealed less hyperactivity and less abnormal agitation, in addition to the fewer seizures.