Yes, we can regrow some cells, but the extent of this ability varies significantly depending on the cell type and the organism.
The Body's Natural Regeneration
All living organisms possess some capacity for cell regeneration as a natural part of tissue and organ maintenance. This is a fundamental process for repairing minor damage and replacing worn-out cells. For example, skin cells are regularly replaced, and the liver has a remarkable ability to regenerate itself after significant damage, even regrowing to a normal size after up to 90% loss. Source: NIH, Cells that maintain and repair the liver identified
However, this regenerative capacity is limited in mammals, including humans. We don't form blastemas (the mass of cells that forms during limb regeneration in some animals), and our regenerative abilities primarily rely on adult stem cells that differentiate into various cell types. Source: NIH, Regeneration
Cell Regeneration Differences
The rate at which cells regenerate varies widely. Skin cells regenerate roughly every 7-10 years, but this is an average; other cell types have different turnover rates. Some cells, like hair cells in the inner ear of mammals, cannot regenerate once they're damaged. Source: Quest Diagnostics, Do my cells really change every 7 years?; Source: Harvard, Scientists Regenerate Hair Cells that Enable Hearing](https://hms.harvard.edu/news/scientists-regenerate-hair-cells-enable-hearing)
Conversely, research shows promise in regrowing certain cells. Scientists are actively investigating ways to stimulate regeneration, such as using bioelectricity to regrow limbs and organs and reprogramming cells to regenerate hair cells in the inner ear. Source: University of Chicago, How bioelectricity could regrow limbs and organs; Source: Mass Eye and Ear, Reprogramming the Inner Ear to Regrow Hair Cells Shows Promise](https://masseyeandear.org/news/press-releases/2019/12/reprogramming-the-inner-ear-to-regrow-hair-cells-shows-promise-to-be-an-effective-target-for-hearing-loss-treatments)
Examples of Regenerative Research:
- Liver Regeneration: The liver demonstrates significant regenerative capacity after injury.
- Neural Regeneration: Research is exploring methods to regenerate neural connections, particularly in the eye. Source: NIH, Lab-grown eye cells form new neural connections
- Hair Cell Regeneration: Studies are investigating ways to regenerate hair cells in the inner ear to potentially treat hearing loss.
