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Vascular and Neurogenic Rejuvenation of the Aging Mouse Brain by Young Systemic Factors

Help the Aged Muscle function declines with age, as does neurogenesis in certain brain regions. Two teams analyzed the effects of heterochronic parabiosis in mice. Sinha et al. (p. 649) found that when an aged mouse shares a circulatory system with a youthful mouse, the aged mouse sees improved muscle function, and Katsimpardi et al. (p. 630) observed increased generation of olfactory neurons. In both cases, Growth Differentiation Factor 11 appeared to be one of the key components of the young blood. A circulating growth factor promotes youthful muscles and brains in aged mice. In the adult central nervous system, the vasculature of the neurogenic niche regulates neural stem cell behavior by providing circulating and secreted factors. Age-related decline of neurogenesis and cognitive function is associated with reduced blood flow and decreased numbers of neural stem cells. Therefore, restoring the functionality of the niche should counteract some of the negative effects of aging. We show that factors found in young blood induce vascular remodeling, culminating in increased neurogenesis and improved olfactory discrimination in aging mice. Further, we show that GDF11 alone can improve the cerebral vasculature and enhance neurogenesis. The identification of factors that slow the age-dependent deterioration of the neurogenic niche in mice may constitute the basis for new methods of treating age-related neurodegenerative and neurovascular diseases.