Both are 'elderly' cells, but there are good and bad, some causing chaos in the body, while others silently protect health. How to accurately identify and distinguish between "good people" and "bad people" in the aging cell population? This has been a long-standing problem in the field of cellular aging. Late at night on October 4, Beijing time, Zhou Bin's research team from the Center for Excellence and Innovation in Molecular Cell Science of the Chinese Academy of Sciences published relevant research results online in the international academic journal Cell. The Zhou Bin research team systematically studied the "fate trajectory" and specific roles of different types of aging cells in the process of liver injury and repair by developing lineage tracing and functional research techniques for cellular aging in vivo. While gaining insight into the "true face" of aging cells, they achieved more accurate "punishing evil and promoting good". Researchers first developed a lineage tracing system for aging cells in the body, and then established corresponding functional research techniques. Researchers have found that after liver injury, cellular aging mainly involves macrophages and endothelial cells. Macrophages surge during liver damage, promoting liver fibrosis; Although endothelial cells also show signs of aging after liver damage, they still play an important role in the repair process, limiting damage and fibrosis. This research work provides important research techniques for the field of cellular aging and regenerative medicine, as well as new research directions and theoretical basis for the clinical treatment of liver related diseases. (New Society)