How to track cellular aging in vitro?
There is a growing perception that culture-expansion, just like aging of the organism, is associated with very specific DNA-methylation changes. However, senescence-associated DNA-methylation changes are not identical with age-associated DNA-methylation changes. Using a broad range of DNA-methylation profiles we elaborated an Epigenetic-Senescence-Signature based on six CpG sites which are combined in a mathematical model to estimate the number of passages and population doublings of cells during culture expansion – thereby supporting a better definition of your cell preparations.
Why is replicative senescence relevant?
All primary cells can only be culture-expanded for a limited number of passages. In the course of culture expansion the proliferation rate decays until the cells enter a senescent state with unequivocal growth arrest after about 40 to 70 population doublings. Culture expansion is also associated with strong morphological changes, impact on the growth pattern, and loss of differentiation potential. Particularly for cellular therapy high quality cells of early passage are favorable. It is therefore of high importance to keep track of replicative senescence. Alternative methods available to estimate the state of cellular aging are not precise - they cannot discern from changes induced by aging of the organism and do not provide estimates of population doublings during culture expansion.
Cygenia provides this service to all scientists working with cells in culture - particularly to those generating therapeutic cell products which necessitate very high quality standards. The Epigenetic-Senescence-Signature has so far been validated for human fibroblasts, mesenchymal stem cells, and human umbilical endothelial cells (HUVECS). The method was trained on various different culture methods to provide robust predictions of cumulative population doublings (cPDs). This approach is also of interest for scientists who want to test the impact of specific growth factors, irradiation, hypoxia etc. on the epigenetic state of cellular aging.
Patent application: 2011; EP 11176593.9