Neonatal thymografts extend old-mouse lifespan

Researchers tested whether transplanting newborn thymus tissue could extend the lives of old mice using a gentler surgical site. The thymus is an immune organ that shrinks with age. Instead of placing grafts beneath the kidney capsule, they placed two newborn-mouse thymi in the axillary cavity, the space beneath the forelimb, of old male BALB/c and nude mice. Mortality was then compared with untreated controls using a survivorship model. The grafted mice showed a significant mortality difference, interpreted by the authors as longer lifespan. The study shows that the axillary site can deliver two neonatal thymus grafts through less invasive surgery while still associating the treatment with extended survival in old mice.