{"id":283,"date":"2014-09-02T20:20:38","date_gmt":"2014-09-02T20:20:38","guid":{"rendered":"http:\/\/joshmitteldorf.peachpuff-wolverine-566518.hostingersite.com\/?p=283"},"modified":"2014-09-02T20:20:38","modified_gmt":"2014-09-02T20:20:38","slug":"transfusing-youth-the-epigenetic-aging-clock-hypothesis-is-about-to-be-tested","status":"publish","type":"post","link":"https:\/\/scienceblog.com\/joshmitteldorf\/2014\/09\/02\/transfusing-youth-the-epigenetic-aging-clock-hypothesis-is-about-to-be-tested\/","title":{"rendered":"Transfusing Youth: the epigenetic aging clock hypothesis is about to be tested"},"content":{"rendered":"

Just this past Spring, Tony Wyss-Coray of Stanford <\/i>demonstrated<\/i><\/a> that infusions of blood plasma from young mice can make old mice grow new brain tissue. \u00a0Others have demonstrated benefits for muscle and liver health. The old mice are healthier, smarter, better healers for the infusion of hormones and dissolved factors (<\/i>not blood cells) from the younger mice. \u00a0Leapfrogging over years of animal tests and investigations, Wyss-Coray is about to test plasma infusions in people. \u00a0<\/i><\/p>\n

(I\u2019m grateful to Adrian Crisan and a reader who identifies himself only as \u201cQuandry\u201d for alerting me to this story. \u00a0This is not what I had planned to write about today, but I\u2019m pumped.)<\/p>\n

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I have argued that much of our age-state may be coded in gene expression\u2014the choice of which genes are active and which are idle. \u00a0We go through life with the same 46 chromosomes we got from our parents, the same DNA, the same genes. \u00a0But different genes are turned on and off \u00a0in different tissues, at different ages. \u00a0This is \u201cepigenetics\u201d, and it determines everything about a cell\u2019s behaviors and activities.<\/p>\n

The epigenetic state of a chromosome is programmed by several different kinds of decorations to the DNA. \u00a0The decorations include methylation, acetylation, and states of tight-winding and unwinding of DNA about molecular spindles called histones<\/a>.<\/p>\n

Does epigentics also determine age? \u00a0In other words, would a young person whose DNA state was epigenetically re-programmed to look like an old person\u2019s actually become old? \u00a0Could the body of an old person fix itself up to look like that of a young person if its DNA was reprogrammed? \u00a0I think it\u2019s a good bet that this will work.<\/p>\n

A separate question is whether it works by a local or a whole-body mechanism. \u00a0Does changing the epigenetic programming of a single cell make that one cell younger, or does it contribute to a hormone environment that makes the whole body a tiny bit younger? \u00a0DNA expression creates proteins that do the cell\u2019s work at home within the cell, and others that circulate through the body as signals, commonly known as \u201chormones\u201d. \u00a0Hormones can affect the decoration of DNA, changing the epigenetics. \u00a0But hormones are also a product of epigenetics. \u00a0Cause, effect, and cause and effect. \u00a0Perhaps this is the basis of a clock, a biological clock that can time development, maturity, puberty and aging. \u00a0It\u2019s an idea I find intriguing<\/a>.<\/p>\n

Up until Sunday, I thought that this idea would be explored at a leisurely pace, indirectly as a result of research with a different conceptual basis. \u00a0I was delighted to learn from this New Scientist<\/i> article<\/a> of trials soon to begin that will test to what extent young hormones can make a person young. \u00a0Here is an interview with Wyss-Coray<\/a> that contains more details.<\/p>\n

History of Parabiosis and Plasma Transfusions<\/b><\/p>\n

About ten years ago, Tom Rando and several students at Stanford picked up and rejuvenated an experimental paradigm that had been used and abandoned in the past. \u00a0They sewed together a young mouse and an old mouse so that they shared a common blood supply. \u00a0[See my previous blog<\/a>, and another<\/a>]. \u00a0Of course, the arrangement was hard on both mice, and they didn\u2019t live long. \u00a0But they lived long enough to determine that the older mouse was receiving benefits from the younger blood: \u00a0faster healing, tissues that looked younger under the microscope, enhanced growth of new nerve and muscle cells.<\/p>\n

There were many directions to take this research:<\/p>\n