KEY POINTS:
- According to a 2024 review in PMC, young blood has been shown to rejuvenate multiple aging organs in mice through heterochronic parabiosis experiments
- Harvard Medical School reports that the protein GDF11 improved exercise capability and brain function in aging mice in studies published in Science
- Columbia University researchers found in 2023 that an anti-inflammatory drug can reverse age-related changes in blood stem cells
Scientific breakthroughs in the field of aging research have revealed that young blood contains rejuvenating properties that can reverse multiple aspects of aging in animal models, bringing humanity closer to understanding and potentially treating age-related diseases.
The Discovery of Blood’s Rejuvenating Effects
According to Stanford Magazine, the first evidence that young blood might mitigate aging effects emerged in the scientific community in 2005. Stanford Magazine reported that a team of Stanford researchers paired old mice with young mice, linking their circulatory systems, and within five weeks, the muscle and liver tissues of the old mice began to resemble those of the young mice.
The technique used in these experiments, called parabiosis, has a long history. According to the PMC ethics paper published in 2018, parabiosis was described by Paul Bert as early as 1864 and gained significant attention during the 1960s and 1970s. The PMC review from 2024 states that in 1980, Butenko and Gubriĭ developed the heterochronic parabiosis model by connecting the circulatory systems of young and old mice.
Widespread Effects on Multiple Organs
The 2024 PMC review documented that young blood rejuvenates multiple aging organs and revealed effects on key anti-aging signaling pathways. According to this comprehensive review, heterochronic parabiosis improves neurogenesis in aging brains, enhances regeneration of aging muscle stem cells, and promotes liver regeneration in aging animals.
Columbia University reported in 2023 that aging hearts beat stronger, muscles become stronger, and thinking becomes sharper when older bodies receive young blood infusions. The PMC review also noted that heterochronic parabiosis has been found to reverse age-related cardiac hypertrophy and improve bone repair in old mice.
Key Proteins Identified
Harvard Medical School reported that researchers at the Harvard Stem Cell Institute demonstrated that a protein called GDF11 can make failing hearts in aging mice appear more like those of young healthy mice. According to the Harvard Medical School article, injections of GDF11 improved the exercise capability of mice and improved function of the olfactory region of the brains in older mice.
Stanford Magazine reported that Tony Wyss-Coray, professor of neurology at Stanford, published a 2014 paper in Nature Medicine stating that exposure of an aged animal to young blood can counteract and reverse preexisting effects of brain aging. According to Columbia University’s 2023 report, researchers found that the aging bone marrow niche is overwhelmed with inflammation, and blocking the inflammatory signal IL-1B with the drug anakinra returned blood stem cells to a younger, healthier state.
The Nature news article from 2023 cited research showing that a protein called PF4, found in blood platelets, can rejuvenate older mouse brains. According to the PMC review, other circulating factors including TIMP-2, GM-CSF, and MANF have shown anti-aging effects when their levels are restored in aged animals.
Clinical Applications and Trials
The PMC review reported that a recent clinical study confirmed the beneficial effects of human umbilical cord blood plasma therapy on various aging indicators in elderly individuals. Stanford Magazine noted that Alkahest, a biotech company co-founded by Wyss-Coray, completed a six-month phase 2 trial in August 2019 where forty patients with mild to moderate Alzheimer’s who had been treated with a plasma fraction showed no significant decline in cognitive function.
According to the PMC ethics paper, the first blood rejuvenation studies on humans with Alzheimer’s disease have already started. Harvard Medical School reported that researchers expect to have GDF11 enter initial human clinical trials within three to five years, as stated by professors Amy Wagers and Lee Rubin.
Scientific Understanding and Mechanisms
Columbia University explained that all blood cells in the body are created by a small number of stem cells that reside in bone marrow, and over time, these hematopoietic stem cells start to change, producing fewer red blood cells and fewer immune cells. According to Columbia University’s research, young blood has the capability to enhance the proliferation of aging liver cells by suppressing the formation of certain protein complexes.
Stanford Magazine reported that Wyss-Coray’s lab showed that plasma could simply be injected without the need for parabiosis, and it didn’t even have to come from the same species. According to Stanford Magazine, when plasma from old people is put into young mice, it makes the brains of mice more inflamed and impairs cognitive function, while plasma from young people put in old mice improves memory function.
Ethical and Practical Considerations
The PMC ethics paper raised significant ethical concerns about blood rejuvenation, stating that using internal substances in some persons as means to rejuvenate others calls for ethical reflection. According to this paper, new types of “blood bonds” may result from the continuous demand for specific types of blood.
Stanford Magazine reported that the FDA issued a warning in February 2019, stating that some patients are being preyed upon by unscrupulous actors touting treatments of plasma from young donors as cures and remedies with no proven clinical benefits. The PMC ethics paper noted that even if rejuvenating substances from blood may be artificially and cheaply produced and justly distributed, problems arise as survival may have to be balanced against reproduction.
According to Stanford Magazine, Wyss-Coray expressed concerns about socioeconomic implications, stating that if something that prolongs life span to 120 in the average population is found suddenly, there aren’t enough resources to cope without massive problems.
Future Directions
Columbia University reported that researchers are now trying to learn if the same rejuvenation processes are active in humans and if rejuvenating the stem cell niche earlier in life, in middle age, would be a more effective strategy. Harvard Medical School noted that the two research groups at Harvard are in discussions with a venture capital group to obtain funding for additional preclinical work necessary before taking GDF11 into human trials.
Stanford Magazine reported that Alkahest is running trials investigating the impact of young plasma on Parkinson’s disease, severe Alzheimer’s, and recovery after surgery, though it is still years away from definitively knowing whether young blood can treat age-related cognitive diseases.
According to Columbia University’s dean of public health Linda Fried, research must be conducted to understand the mechanisms of normal aging and how to fully develop the opportunities to create healthy longevity for all.
