Mice Share Circulatory System to Examine Blood Age Effects

Scientists have studied the link between blood, age, and rejuvenation for years. Blood health, and the biological age of components in the blood, are widely considered to be predictive of overall health. A new study published in Rejuvenation Research attempts to directly study the connection between blood and health. Using heterochronic parabiosis, the study’s authors attempted to determine whether blood alone could contribute to biological aging. 

Parabiosis is a technique used by laboratory researchers to connect the circulatory system of two organisms. In this study, a series of laboratory mouse pairs had their circulatory systems connected, with blood being shared between the two mice. The researchers paired young mice with old mice and examined the mice for health changes. Theoretically, if the blood from the young mouse has protective effects, the older mouse’s health should improve. Similarly, if blood for the old mouse is harmful, the younger mouse’s health should deteriorate. 

The results of the study were mixed. The old mice in the mouse pairs did not demonstrate any statistically significant increase in their lifespan. However, young mice whose circulatory system was connected to old mice exhibited a substantial decrease in their lifespan. The researchers were not able to demonstrate that young blood offers protective effects, but they were able to bolster the theory that old blood can have harmful effects. 

Researchers continue to examine the links between blood age and age-related disorders. The results of the study are broadly consistent with other rejuvenation-centered experiments. A previous study by the same scientists found no benefit of young blood infusions in healthy mice. That study was performed using blood transfusion, not parabiosis. 

It is worth noting that there could be confounds in the research which obscure the possible health benefits the old mice may have received. The researchers point to the risks associated with parabiosis or preexisting age-related disorders as likely culprits.