{"id":988,"date":"2020-06-08T01:36:47","date_gmt":"2020-06-08T01:36:47","guid":{"rendered":"http:\/\/joshmitteldorf.peachpuff-wolverine-566518.hostingersite.com\/?p=988"},"modified":"2020-06-08T16:24:49","modified_gmt":"2020-06-08T16:24:49","slug":"out-with-the-old-blood","status":"publish","type":"post","link":"https:\/\/scienceblog.com\/joshmitteldorf\/2020\/06\/08\/out-with-the-old-blood\/","title":{"rendered":"Out With the Old Blood"},"content":{"rendered":"

There is great promise in 2020 that we might be able to make our bodies young without having to explicitly repair molecular damage, but just by changing the signaling environment.<\/p>\n

Do we need to add signals that say \u201cyoung\u201d or remove signals that say \u201cold\u201d?<\/p>\n

Does infusion of biochemical signals from young blood plasma rejuvenate tissues of an old animal? Or are there dissolved signal proteins in old animals that must be removed?<\/p>\n

For a decade, Irena and Mike Conboy have been telling us removal of bad actors is more important. But just last month, Harold Katcher reported spectacular success by infusing a plasma fraction while taking away nothing. Then, last week, the Conboys came back with a demonstration of the rejuvenating power of simple dilution. [Link to their new paper<\/a>]<\/p>\n

Dilution procedure<\/span><\/p>\n

They simply replaced half of the blood plasma in 2-year-old mice with a saline solution containing 5% albumin.\u00a0What is albumin?\u00a0<\/span>Blood plasma is chock full of dissolved proteins, about 10% by weight. About half of these are termed albumin. Albumin is the generic portion. It doesn\u2019t change through the lifetime. It doesn\u2019t carry information by itself. But albumin transports nutrients and minerals through the body.<\/p>\n

The Conboys took care to show that albumin has no rejuvenation power on its own, and had nothing to do with their experimental results. Rather, they had to replenish albumin in diluting blood, because the animals would be sickened if half their albumin were removed. Replacing the albumin in a transfusion is akin to replacing the volume of water or maintaining the salinity.<\/p>\n

In preparation for this experiment, the Conboys have invested years in miniaturizing the technology for blood transfusions, so that mice can be subjected to the same procedures that are commonplace in human hospitals.<\/p>\n

Dose-Response<\/span><\/p>\n

The Conboy lab replaced 50% of mouse blood plasma. They got spectacular results with a single treatment, based on a lucky guess. They have not yet experimented with 30% or 70%. They don\u2019t know yet how long the treatment will last and how often it needs to be repeated.<\/p>\n

Evidence of rejuvenation<\/span><\/p>\n

As with previous papers from the Conboy lab, the group focused on repair and stem cell activity as evidence of a more youthful state. Three separate tissue samples were taken from liver, muscle, and brain.<\/p>\n

\u201cMuscle repair was improved, fibrosis was attenuated, and inhibition of myogenic proliferation was switched to enhancement; liver adiposity and fibrosis were reduced; and hippocampal neurogenesis was increased.\u201d<\/p><\/blockquote>\n