Study provides hope of stimulating myelin sheaths around nerves.

Age-related effects of MS may prove reversible
Study provides hope of stimulating myelin sheaths around nerves

In a study, researchers report that defects in the regeneration of the myelin sheaths surrounding nerves, which are lost in diseases such as MS, may be at least partially corrected after exposing an old animal to the circulatory system of a young animal. The research was led by Associate Professor Amy Wagers (above) of Harvard’s Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute./ B. D. Colen/Harvard Staff

Harvard stem cell researchers and scientists at the University of Cambridge in the United Kingdom have found that the age-related degeneration in conditions such as multiple sclerosis (MS) may be reversible.

The researchers, co-led by Associate Professor Amy Wagers of Harvard’s Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, has found that impairment of the body’s ability to replaceprotective myelin sheaths, which surround nerve fibers and allow them to send signals properly, may be reversible, offering new hope that therapeutic strategies aimed at restoring efficient regeneration can be effective in the central nervous system throughout life.

In a proof-of-principle study published in the journal Cell Stem Cell, the researchers report that defects in the regeneration of the myelin sheaths surrounding nerves, which are lost in diseases such as MS, may be at least partially corrected after exposing an old animal to the circulatory system of a young animal. Myelin is a fatty substance that protects nerves and aids in the quick transmission of signals between nerve cells.

Using a surgical technique, the researchers introduced an experimental demyelinating injury in the spinal cord of an old mouse, creating small areas of myelin loss, and then exposed those areas to cells found in the blood of a young mouse. By doing so, they found that the influx of certain immune cells, called macrophages, from the young mouse helped resident stem cells restore effective remyelination in the old mouse’s spinal cord. This rejuvenating effect of young immune cells was aided in part by the greater efficiency of the young cells in clearing away myelin debris created by the demyelinating injury. Prior studies have shown that this debris impedes the regeneration of myelin.

“Aging impairs regenerative potential in the central nervous system,” said Wagers, who is based at the Joslin Diabetes Center, and who co-led the study with Professor Robin Franklin, director of the MS Society’s Cambridge Centre for Myelin Repair at the University of Cambridge. “This impairment can be reversed, however, suggesting that the eventual development of cell-based or drug-based interventions that mimic the rejuvenation signals found in our study could be used therapeutically.”

This could be particularly useful, she said, in treating MS, which typically spans many decades of life, and thus is likely to be influenced by age-dependent reductions in the ability of myelin to regenerate. In MS, the body’s own immune system attacks the myelin sheath and prevents nerve fibers in the brain from sending signals properly, which can cause mild symptoms such as limb numbness or more serious ones like losing the ability to walk or speak. As people with MS age, remyelination decreases significantly, eventually causing permanent loss of nerve fibers.

“For MS sufferers,” said Franklin, “this means that, in theory, regenerative therapies will work throughout the duration of the disease. Specifically, it means that remyelination therapies do not need to be based on stem cell transplantation, since the stem cells already present in the brain and spinal cord can be made to regenerate myelin, regardless of a person’s age.”

Other Harvard co-authors of the study were Tata Nageswara Rao and Jennifer L. Shadrach of Wagers’ lab.

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About Harvard Medical School (HMS)

Driving Change. Building Momentum. Making History. 

“Since 1872, Harvard Medical School has been the incubator of bold ideas—a place where extraordinary people advance education, science and health care with unrelenting passion.

Whether training tomorrow’s doctors and scientists, decoding the fundamental nature of life, advancing patient care or improving health delivery systems around the world, we are never at rest. Allied with some of the world’s best hospitals, research institutes and a University synonymous with excellence, the School’s mission remains as ambitious as it is honorable: to alleviate human suffering caused by disease.”

More at Harvard Medical School & Harvard Medical School. Generations of Leaders.

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About Harvard School of Public Health (HSPH)

Harvard School of Public Health is dedicated to advancing the public’s health through learning, discovery and communication. More than 400 faculty members are engaged in teaching and training the 1,000-plus student body in a broad spectrum of disciplines crucial to the health and well being of individuals and populations around the world. Programs and projects range from the molecular biology of AIDS vaccines to the epidemiology of cancer; from risk analysis to violence prevention; from maternal and children’s health to quality of care measurement; from health care management to international health and human rights.

More at Harvard School of Public Health (HSPH) & Harvard School of Public Health (HSPH). History.

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About Harvard University.

Established in 1636, Harvard is the oldest institution of higher education in the United States. The University, which is based in Cambridge and Boston, Massachusetts, has an enrollment of over 20,000 degree candidates, including undergraduate, graduate, and professional students. Harvard has more than 360,000 alumni around the world.

Harvard University is devoted to excellence in teaching, learning, and research, and to developing leaders in many disciplines who make a difference globally. Harvard faculty are engaged with teaching and research to push the boundaries of human knowledge. For students who are excited to investigate the biggest issues of the 21st century, Harvard offers an unparalleled student experience and a generous financial aid program, with over $160 million awarded to more than 60% of our undergraduate students. The University has twelve degree-granting Schools in addition to the Radcliffe Institute for Advanced Study, offering a truly global education.

‘Universities nurture the hopes of the world: in solving challenges that cross borders; in unlocking and harnessing new knowledge; in building cultural and political understanding; and in modeling environments that promote dialogue and debate… The ideal and breadth of liberal education that embraces the humanities and arts as well as the social and natural sciences is at the core of Harvard’s philosophy. ’/ Drew Gilpin Faust

More About Harvard University & About Harvard University. Information.

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*  The above story is adapted from materials provided by Harvard University

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