[ipaddr]

I was under the impression all cells in the body will be regenerated in 7 years.

[laplacesdemon48]

Loss of neurons and cardiac muscle cells is permanent. Emergency medical personnel are usually taught "time is brain" and "time is heart" for this reason.

Some body cells can bounce back after serious trauma, liver cells being a prime example: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2701258/