Our goal is to develop a cellular strategy for repairing the damage seen in children's myelin disease, Multiple Sclerosis and other neurological diseases.

 
Scientists Restore Crucial Myelin In Brains Of Mice



Scientists for the first time have restored a crucial substance known as myelin in a widespread area of an animal's brain, opening the door toward new ways to improve treatment of an assortment of "demyelinating" diseases as well as the side effects of such common conditions as high blood pressure and heart disease. The research by a team led by Steven Goldman, M.D., Ph.D., of the University of Rochester Medical Center, is in the January issue of Nature Medicine.

The work has implications for a wide variety of children's diseases known as pediatric leukodystrophies, where the myelin is damaged or doesn't work correctly, such as Canavan disease, Krabbe disease, or Tay-Sachs disease.

The team remyelinated the mice – restored the "insulation" to the brain cells– by injecting into the mice highly purified human "progenitor" cells, which ultimately evolve into the cells that make myelin. These cells are known as oligodendrocytes: While these and other types of glial cells aren't as well known as information-processing brain cells called neurons, they are vital to the brain's health.

Goldman says that while scientists have used other methods during the past two decades to remyelinate neurons in small portions of the brains of mice, the remyelination seen in the Nature Medicine paper is much more extensive. He estimates that about 10 percent of the axons in the mouse brains were remyelinated, compared to a tiny fraction of 1 percent in previous studies.

In addition to MS, many diseases affecting tens of millions of people in the United States involve myelin problems, Goldman says. These include widespread diseases like diabetes, heart disease and high blood pressure, where decreased blood flow can damage myelin and hurt brain cells, as well as strokes, which often destroy brain cells in part by knocking out the cells that pump out myelin. In addition, cerebral palsy is largely caused by a myelin problem in infants born prematurely.

The team found that adult human cells were much more adept at settling into the brain, becoming oligodendrocytes and producing myelin than the fetal cells. After just four weeks, adult cells but not fetal cells were producing myelin. After 12 weeks, four times as many oligodendrocytes derived from adult cells were producing myelin – 40 percent, compared to 10 percent of the cells from fetal cells. In addition, adult cells were likely to take root and form oligodendrocytes, not other brain cells such as neurons or astrocytes, which are not necessary for myelin production. On average, each oligodendrocyte from an adult cell successfully remyelinated five axons, compared to just one axon for fetal cells.


posted by Canadian Myelin Research Initiative at 11:56 AM