Figure 1: Gut microbes stimulate hormonal and immune signaling for healthful longevity. Healthful aging is generally associated with host ability to respond to tissue damage with efficient homeostatic balance and minimal pathology. Efficient injury repair and lifelong good health are regulated by hypothalamic hormones (e.g., oxytocin) integrated with peripheral endocrine glands (i.e., adrenal cortex, thyroid gland, and gonads) in conjunction with the systemic immune system. Beneficial gut microbes were recently found to stimulate oxytocin that up-regulates Interferon (IFN)-γ and CD25 expression for immune tolerance in a transplantable fashion. Together this prevents over-reactivity to self or environmental factors that otherwise lead to premature death.