Background: 

Cell based medicinal products involve risks, therefore, it is extremely important to prove the safety of these innovative treatments. We have developed procedure to determine the viability of human mesenchymal stem cells (hMSCs) by analyzing mitochondrial function thus ensure the safety of hMSCs in future cell therapy treatments.

Methods and results: 

FACS-based method to monitor the inner membrane potential of mitochondria was established. The fluorescent membrane-permeant cation, rhodamine123, was used in quench mode. Mesenchymal stem cells were exposed to 2.6 mM Rhodamine123 and 7AAD was used to detect dead cells. Mitochondrial DNA (mtDNA) from hMSCs of different aged patients was analyzed by expand PCR to determine the amount of deletions. Results have shown that there are variations in viability between hMSC lines. The proliferation capacity of analyzed cells has correlated to the rhodamine123 intensity. Analyzed cells can be categorized into three groups based on the proliferation capacity and rhodamine123 intensity. Cells that proliferate rapidly have rhodamine123 intensity about 2–3 times lower than cells that do not proliferate so actively. mtDNA deletions have been found from three different patients, some were heteroplasmic small deletions and others homoplasmic larger deletions.

Conclusions: 

It is possible to distinguish cell populations with different proliferation capacities by this FACS-based method. In future, the idea is to improve the sensitivity of this test. mtDNA analysis have revealed interesting results (3 deletions from 17 patients) and needs more investigations in future.