Hayflickhatárként

Hayflickhatárként refers to the phenomenon observed by Leonard Hayflick in the 1960s. He discovered that normal human cells, when cultured in vitro, have a finite number of times they can divide before they stop proliferating. This limit is known as the Hayflick limit. Hayflick demonstrated that these cells enter a state of senescence, a permanent growth arrest, rather than dying. Initially, it was thought that this limit was a universal constant for all cell types, but further research has shown variations. The Hayflick limit is closely linked to the shortening of telomeres, the protective caps at the ends of chromosomes. Each time a cell divides, telomeres shorten. When they become critically short, the cell triggers the senescence pathway. This cellular aging process is believed to play a role in organismal aging and the development of age-related diseases. However, some cells, such as germ cells and cancer cells, possess mechanisms like telomerase, an enzyme that can rebuild telomeres, allowing them to bypass the Hayflick limit and continue dividing indefinitely. Understanding the Hayflick limit has been crucial in fields like aging research, cancer biology, and regenerative medicine.