Subject: What are the aging-mechanisms in a gut cell, that lives only 2 days?

In search for mechanisms of cell aging, I found only such articles and 
reviews that are related to cell aging in context of the 
aging-phenomen of the entire organism. So these texts are dealing with 
matters like telomer-shortening, (mito)DNA-deletion etc.
Instead of this I´m searching answers to questions like:
Why lives a gut epithelium cell shorter than a liver cell?
What is the mechanism of aging in one single liver (epidermal...)cell
in both the young child and the old man?

Re: What are the aging-mechanisms in a gut cell, that lives only 2 days?