stem cell question, Dr. Young

[Birde]

Dr. Young, isn't it true that embrionic stem cells are so minute that in reality it would take thousands/millions for the use in one human adult spinal cord in order to see if there was any benefit...not nearly so many needed in a rats spinal cord.

[Wise Young]

Interesting question. Nobody really has addressed the question of optimal dose of stem cells, i.e. the number of cells injected. The question is complicated by several issues. First, the stem cells themselves proliferate (divide to produce more cells). The proliferation of stem cells after injury depend on many factors. Embryonic stem cells tend to divide faster and may respond differently to the environment to produce more or less cells under different circumstances, i.e. how long after injury. Second, the injection site and environment is important. This is seldom controlled.

Wise.

[pecla]

In Dmitriy's case they injected 11 million(!) stem cells.

[Wise Young]

In a rat, we often inject 50,000 to 100,000 cells. Wise.