Young V. Old (IMAGE) University of Pennsylvania School of Medicine Caption An enzyme called SIRT1 declines in the blood vessels with age and restoring it reverses the effects of vascular aging. After receiving a supplement called NMN, older mice showed increased capillary density, blood flow, mobility, and endurance. Credit Cell; Zolt Arany, Perelman School of Medicine, University of Pennsylvania Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.