Scientists have successfully tested a blood component capable of becoming a "youth serum"
Tiny extracellular bubbles from the blood plasma of the young can significantly extend life and reverse age-related degenerative changes in the old. In experiments on laboratory mice, Chinese scientists have shown this, thus moving closer to creating a universal way to fight aging and improve human health.
Researchers have long experimented with transfusion of blood, its components and other physiological fluids from young mice to old ones in search of methods to rejuvenate the body and increase life expectancy. In one of these experiments, scientists from the U.S. surgically connected the circulatory systems of young and elderly rodents, which allowed to slow down the aging of the latter. In order to rejuvenate the mice were also injected with platelets, injected with cerebrospinal fluid and transplanted fecal microbiota of the intestine.
In a recent study published in the journal Nature Aging, a large team of experts from Nanjing University (PRC) tested another technique using small extracellular vesicles, or vesicles (small extracellular vesicles, sEVs) - particles smaller than 200 nanometers from blood plasma. According to scientists, this blood component has a number of important advantages over others, which makes it possible to move more quickly to clinical application of the method.
Laboratory mice of the C57BL/6J line were used in the experiments. Once a week elderly males aged 20 months were injected intravenously with 200 microliters of pure phosphate-salt buffer solution (control group) or the same volume of solution with "young" extracellular vesicles at a concentration of 1.80 micrograms of total protein per microliter. The experimental preparation was previously made from purified blood plasma of young mice of two months of age, bringing it to the required concentration simulating the natural content of extracellular vesicles in the blood.
The subjects were monitored until their death. Survival analysis showed that the rodents receiving the drug lived on average almost 13% longer than the animals from the control group. The average life expectancy of the former amounted to 1031 days. This is 22.7% longer than the typical life span of 840 days for male mice of the C57BL/6J line. The longest-lived mouse in the experimental group died 1266 days after birth, which is equal to 120-130 years in human terms.
The rodents injected with the "serum of youth" generally retained a healthier appearance than the control mice. In particular, the drug helped prevent hair loss, counteracted aging at the molecular, mitochondrial, cellular and physiological levels, and mitigated age-related functional decline in various tissues, including the hippocampus, muscles, heart, testes, bones and others.
In a press release, the authors emphasized that the new method was one of the most effective in rejuvenating and prolonging the life of the mice. In previous studies, calorie-restriction therapy helped bring the subjects' average lifespan to 978 days (+16.4%), while taking metformin and nicotinamide increased it to 889 (+5.8%) and 875 days (+4.2%), respectively.
In addition, small extracellular vesicles are naturally occurring nanoparticles circulating in the bloodstream, which means they do not induce toxic or immunologic responses. Therefore, their administration could be a versatile tool to fight aging, treat age-related diseases and improve human health.
Despite the promising results of the experiment, the researchers recognized that it is necessary to confirm the efficacy and safety of such injections in clinical trials before talking about the application of the new method on humans.