Are there any "immortal" cells in the human body?

[debit]

Dear Dr. Steve,

Are any of the original cells that we are born with still with us by the time we are 60? I didn't take biology so I don't know jack about this.




Thx

[Dr Steve]

Dear Dr. Steve,

Are any of the original cells that we are born with still with us by the time we are 60? I didn't take biology so I don't know jack about this.




Thx

sure! every single brain cell that you were born with. Brain cells don't divide and multiply. Synapse formation (the process of forging new circuits) goes on until death, but the cells themselves don't turn-over, like skin cells do. Most every other cell type dies and is replaced, and at different rates.

I found this summary of an article by Spaulding, et al in the journal "Cell":

They found the average age of intestinal tissue to be about 11 years, and after accounting for epithelial cells (which have short lifespans of only 5 days) found the average age of non-epithelial intestinal tissue to be 15.9 years. Skeletal muscle tissue was found to have an average age of 15.1 years. In the brain, tissues appear to be much older. The average age of the cerebellum's gray-matter was only 2.9 years younger than the person, and the average age of occipital-cortex gray matter was about 10 years younger than the person, but the age of occipital-cortex neurons was found to be the same as the age of the person.

So, even though we think of our bodies as being permanent structures, most of our tissues (outside of our brains) are continually being turned over, renewed in a balance between the constant death of old cells (likely through the process of apoptosis) and the constant birth of new cells. In last week's New York Times article about this paper, Dr. Frisen (the senior author) suggested that the average age of the cells in an adult human may be as low as seven to ten years. Remember, this is an average value. As shown by Spalding et al, the value varies by tissue.

hope this helps!



steve

[Bob Impact]

sure! every single brain cell that you were born with. Brain cells don't divide and multiply. Synapse formation (the process of forging new circuits) goes on until death, but the cells themselves don't turn-over, like skin cells do. Most every other cell type dies and is replaced, and at different rates.

FYI... my brain cells are not only capable of growth, they've also formed a small exploratory colony near my ear canal and are regularly sending very very small rocket ships into my nose.