The disclosure is directed to the use of nonviable pluripotent stem cells to improve age-related declines in tissue and organ function. In one aspect, nonviable pluripotent stem cells are used to improve cognition in a subject in need thereof. In another aspect, nonviable pluripotent stem cells are used to improve age-related cardiac dysfunction in a subject in need thereof. Administration of nonviable pluripotent stem cells provides a transient and safe form of heterochronic cellular transbiosis.
