One reason for waning capabilities with advancing age is a
progressive decline in organ function. Heterochronic parabiosis rejuvenates the performance of old
tissues' stem cells at some expense to the young, but whether this is through shared circulatory
factors or shared organ systems is unclear; and parabiosis is not a clinically adaptable approach. The old heterochronic partners have access to young organs, environmental enrichment and youthful
hormones/pheromones, while the young parabiont maintains an additional aged body with deteriorating organs.
In contrast to the permanent anastomosis of parabiosis, UC Berkeley researchers have used a small animal blood exchange where animals are connected and disconnected at will, removing the influence of shared organs, adaptation to being joined, etc. The effects of heterochronic blood exchange were examined with respect to all three germ layer derivatives: injured-regenerating muscle, ongoing liver cell proliferation and brain - hippocampal neurogenesis, and in the presence and absence of muscle injury. The influence of heterochronic blood exchange on myogenesis, neurogenesis and hepatogenesis was fast, within a few days. These findngs suggest a rapid translation of blood apheresis (FDA approved for other diseases, but not for the degenerative pathologies) for therapy to attenuate and reverse liver fibrosis and adiposity, muscle wasting and neuro-degeneration.