Tuesday, 7 May 2013

A Possible Epilepsy Treatment - Transplanting Brain Cells

Some exciting research performed at the University of California has shown that transplanting a specific type of cell into the brain of a mouse can cure or significantly relieve epilepsy. The research is intriguing because the process may very well work in humans too. The mice that were tested were suffering from a condition resembling mesial temporal lobe epilepsy in humans. This is a severe disorder that generally doesn't respond to medications.

The cells that were transplanted into the mice brains are known as medial ganglionic eminence cells, or MGE cells. They're found in both mouse and human embryos. The MGE cells need to be placed in the hippocampus to do their job. The hippocampus is a region of the brain that plays a role in memory and is involved in epileptic seizures. It received its name because it resembles the shape of a seahorse, whose scientific name is Hippocampus. The researchers found that the MGE cell transplant eliminated epilepsy in half of the treated mice and dramatically decreased the number of seizures in the rest.

Most cells in our body are specialized for specific functions and can no longer divide. Stem cells are unspecialized cells, however, and are able to divide throughout their lives. Stem cells divide to produce more stem cells and progenitor cells. Progenitor cells are slightly more specialized than the stem cells. The progenitor cells divide to make cells that are even more specialized. The cell division and specialization continue until the target cell type is produced. MGE cells are progenitor cells.

Top Picture = Human Embryonic Stem Cells
Bottom picture = Nerve cells made from the stem cells
Photos by Nissim Benvenisty, CC BY-SA 2.5 License
When MGE cells are placed in the hippocampus of a mouse brain they migrate to the correct area and produce nerve cells called interneurons. During an epileptic seizure, an abnormally large number of brain cells become active at the same time and transmit nerve impulses synchronously, producing a seizure. The interneurons made from MGE cells inhibit the excess transmission of nerve impulses that occur in the mice during an epileptic seizure. The new interneurons replace cells lost from the mouse hippocampus.

The researchers have managed to produce cells that resemble human MGE cells in the laboratory, avoiding the need to use embryos. It's not known for certain whether the MGE cells will work the same way in the human brain as in the mouse brain, but there is a good probability that they will. The scientists' discovery could be a very important breakthrough in the treatment of human epilepsy. The research report is published in Nature Neuroscience.