Young Blood May Hold Key to Reversing Aging

Gabriella Ricciardone
May 18, 2014

Author:  Carl Zimmer
Published:  May 4, 2014

Summary:
This past Sunday, studies were published that show that blood from young mice can effectively rejuvenate the muscles and brains of old mice.  Continuing this research could lead to the discovery of treatment for diseases such as Alzheimer’s and heart disease.  These studies build on the centuries-old idea that the blood of young people contains substances that might revitalize older people.  A few decades ago, it became clear that stem cells are essential for keeping tissues alive.  Stem cells produce new cells to replace dying ones when tissues are damaged.  As people age, their stem cells weaken.  In the early 2000s, scientists came to the realization that stem cells were not dying off in aging tissues; rather, they just were not getting the correct signals.  There were still plenty of stem cells there.  So, researchers joined old and young mice together, in a procedure known as parabiosis, just as Dr. Clive McCay did back in the 1950s to try to find the answer to the same question.  The experiment proved that there were certain compounds in the blood of young mice that could awaken stem cells and rejuvenate aging tissues.  Similarly, the blood of old mice had compounds that weakened the resilience of the young mice, and made the young mice grow prematurely old, with slower muscle healing ability and slower stem cell productivity.  One scientist, Dr. Amy J. Wagers, screened the blood of the mice and found that protein GDF11 was abundant in young mice but scarce in old mice.  She and her team also found that GDF11, even on its own, could effectively rejuvenate the hearts and stem cells in old muscles of the mice.  A study at Stanford in 2011 reported that the blood of younger mice gave bursts of new neurons in the hippocampus of older mice when injected, and allowed for better memory formation.  The same team from Stanford decided to remove the cells and platelets from the blood of young mice and inject them into the old mice through the remaining plasma, which ended up causing the old mice to perform better on memory tests.  Scientists hope to one day use this technique and data to help reverse aging in humans as well.

Connection:
During our studies of Chapter 30, we discussed the functions of blood, platelets, and plasma in the body.  This article is mainly about the role of young blood and platelets in the rejuvenation of old blood and platelets.  We also studied brain functions and neurons during our discussions of Chapter 28, and part of the studies shown above included the improvements in the functions of the hippocampus in older mice when injected with blood of younger mice.  We also briefly covered Alzheimer's disease in class, and this research will hopefully be, one day, used to help reverse the effects of Alzheimer's in human beings.  During Chapter 30 we also discussed the heart and heart disease and these studies are being done to help reverse the effects of heart disease as well.  Stem cells, tissues, and muscles were also discussed during our learning in class.