Dear stem cell biologists and bioinformaticians: I’ve got a pretty serious question for you. How would you define and quantify the native (endogeneous, in-built) regenerative potential of a tissue/organ or more generally of a specially localized functional cell population in the human body? In the literature the term “regenerative potential” of a tissue is often used concerning the response to damage and repair due to the contribution of the tissue-specific resident stem cell niche or from the circulation, but I haven’t found any strict and quantitative concept and definition yet. If you do please inform me. A working operational definition (update: of a regenerative potential of a tissue/organ) designed to model a conceptual definition could be the basic building block of a whole body regeneration model, which is needed for any attempt to launch systemic regenerative medicine.
So here is my initial offer:
Let us assume that we calculated the following cell numbers of a tissue/organ with some method (stereology, fluorescence activated cell sorter, theorethical calculation based on other measurements and data):
- number of differentiated functional cells
- number of tissue, organ and lineage specific endogenous stem cells
- number of tissue, organ specific progenitor (or transit amplifying cells TACs) cells.
Based on the estimated proportion of stem cell/differentiated cells or TACs/differentiated cells in a defined tissue or organ I’d like to introduce the tissue and organ specific theoretical and practical Regenerative Potential.
I define the Theorethical Regenerative Potential of a tissue or organ as follows: the ratio of quiscent self-renewing stem cells in a stem cell niche/differentiated cells in a tissue or organ. (Or we can use all cells= differentiated+stem+TACs as a denominator.) Continue reading