Ageing decelerates a person’s metabolism and makes the person more sluggish. It leads to several debilitating conditions like cancer, dementia etc. that can be attributed to several causal factors. In the current scenarios, each of these diseases are treated separately, however some researchers attempt to treat ageing itself instead of treating separate diseases. Imagine what would happen if the process of ageing could be negated or decelerated by injecting young blood into a person’s body. This might seem like a farfetched idea that could make a good script for a science fiction film.
Saul Villeda proved his hypothesis that ageing could indeed be decelerated by injecting young blood in old mice. Villeda surgically conjoined a pair of mice in which one was a young mouse and the other was aged. The young mouse received blood and other nutrients from the older mouse and the aged mouse received its blood from the young mouse.
At the end of the experiment, Villeda sliced the brains of the mice used in the experiment and counted the number of neurons. He observed that the number of new neurons in the brains of the aged mice used in the experiment was three to four times higher than their counterpart mice who did not receive blood from younger mice. Conversely, the young mice that received blood from the old mice, exhibited signs of ageing.
Villeda is not the first to experiment on the process of ageing by surgically conjoining mice. Scientists attempted an experiment by conjoining old and young mice and studied muscle repair. As expected the old rats fared better than their non-conjoined counterparts.
Villeda observed that old mice, like old humans had high levels of a protein named C11 in their blood. This protein when injected into the blood stream of young mice caused undesirable effects. Sluggishness, decreased brain activity and the inability to adapt to surroundings were some of the effects exhibited. Villeda also performed plasma transfusions from young mice to the old mice and observed that the old mice had the mental capability of mice half their age.
It was observed that genes that controlled synaptic plasticity become less active once an animal begins to age. By injecting plasma, this gene was activated again.
Wyss Coray, Villeda’s supervisor conducted a study to compare the blood of the young and old among humans. He inferred that the levels of certain proteins in humans considerably reduced as the person aged. Some protein levels dropped at the age of twenty, while some increased considerably. However the effects of increase and decrease of specific proteins have not been looked into.
Wyss Coray was not the first person to experiment on the transfusion of blood between people of different ages. In the 17th Century, Andreas Libavius, a German Doctor hypothesized that an aged person would become younger by fusing his blood vessels with that of a younger person. However the results of his work are unknown. During the same period, transfusion experiments were deadly as coagulation factors and compatibility was unheard of. Hence there was a ban on transfusions for a century, until the processes involved in blood interactions was better understood.
Tom Rando, a colleague of Wyss Coray, supervised a series of experiments in which mice were surgically sewn together through a process known as ‘Parabiosis’. It was initially believed that parabiosis was detrimental as incompatible animals killed each other. However with the advent of genetic compatibility matching and careful supervision, parabiosis is not as gruesome as it was.
Rando believed that the stem cells in older mice could be turned on using chemical cues from the blood of the younger mice. His experiment was successful and it was observed that the older of the conjoined mice had developed the ability to repair muscle tears. Also, he observed changes in the number of neurons.
Currently Alkahest, a company founded by Wyss Coray and his colleagues, is attempting to transfuse young blood plasma into patients suffering from moderate to severe Alzheimer’s. Whether the patients benefit from the trial or not can be observed only at the end of the trial. The patients received plasma from donors below 30 and there is a possibility that the plasma is not sufficiently potent.
The results of these studies are remarkable and could help in treating patients with dementia and other neuronal disorders but the study also has downsides. Injecting pro-youthful proteins in old people could result in cancer. Also the requirement for young blood could result in a black market.
Source: The Guardian.