Via EurekAlert!: "As a person ages, the ability of their beta cells to divide and make new beta cells declines. By the time children reach the age of 10 to 12 years, the ability of their insulin-producing cells to replicate greatly diminishes. If these cells, called beta cells, are destroyed - as they are in type 1 diabetes - treatment with the hormone insulin becomes essential to regulate blood glucose levels and get energy from food. Now, [researchers] have identified a pathway responsible for this age-related decline, and have shown that they can tweak it to get older beta cells to act young again - and start dividing. ... a protein called PDGF, or platelet derived growth factor, and its receptor send beta cells signals to start dividing via an intricate pathway that controls the levels of two proteins in the beta cell nucleus, where cell division occurs. Working with young mice, [researchers] found that PDGF binds to its receptor on the beta cell's surface and controls the level of these regulating proteins allowing cells to divide. However, in older mice, they discovered that beta cells lose PDGF receptors, and that this age-related change prevents beta cells from dividing. [Researchers] further found that by artificially increasing the number of PDGF receptors, they can restore the ability of the beta cell to divide and generate new cells. ... By understanding what genes are turned on and off in a young beta cell, we can try to recreate that genetic environment in older beta cells such that they divide in a desirable, controlled manner."