Using genetic engineering to design a human that does not age is a complex and still-researched area. Here are some possible pathways and considerations: 1. **Telomere maintenance**: Telomeres are protective caps at the ends of chromosomes. As the number of cell divisions increases, telomeres gradually shorten, leading to cell aging and loss of function. By genetically engineering the activity of telomerase (TERT), telomere length can be extended, thereby delaying cell aging. However, this also needs to be carefully managed to avoid cancer risks, as over-activation of telomerase may cause cells to proliferate indefinitely. 2. **DNA damage repair**: Accumulation of DNA damage with age is a key factor leading to aging. Cell repair capacity can be improved by enhancing gene expression of DNA repair mechanisms or editing and introducing or improving proteins related to DNA repair (such as genes in PARP1, ATM, and NAD+ pathways). 3. **Regulation of apoptosis and senescence**: Apoptosis (programmed cell death) and cellular senescence (cell cessation of division) are important mechanisms for controlling cell quality and quantity, but their dysregulation can also lead to aging and related diseases. Regulating the expression of key genes in these processes (e.g., p53, p16INK4a) may affect the aging process. 4. **Improvement of mitochondrial function**: Mitochondria are the energy factories of cells, and their damage is associated with a variety of aging-related diseases. Improving the stability of mitochondrial DNA or enhancing mitochondrial function through genetic engineering can slow down the aging process to a certain extent. 5. **Antioxidant defense pathway**: Excessive oxidative stress can cause cell damage and aging. Oxidative damage can be reduced by increasing the levels of endogenous antioxidants (e.g., superoxide dismutase, glutathione system). 6. **Systemic regulation**: Systemic changes in the whole body, such as by regulating genes related to metabolism and inflammation (e.g., SIRT family genes, AMPK, mTOR pathway), may lead to overall health improvements and life extension. It should be noted that designing humans who will not age involves multidisciplinary collaboration, including bioethics, as this may bring complex social and ethical challenges. In addition, due to the complexity and interconnectedness of biological systems, there is still no simple way to completely stop or reverse human aging. Current research focuses mainly on extending the length of healthy life rather than achieving true non-aging.