What is the optimal method through which to passage iPSCs/hESCs to minimize karyotypic anomalies from occurring?

Answer

There are a few recent articles which suggest that manual dissociation of PSCs rather than enzymatic treatment results in fewer karyotypic anomalies (Stem Cells and Development (2015) 24:653-662 & PLOS ONE (2015) 10(2)). However, in addition to the passaging method the following parameters can have a significant impact on the genomic stability of cultures, (1) growth medium, (2) matrix, (3) confluency at the time of passaging. One of the causes of genomic instability of cultures is the generation of reactive oxygen species associated with stressful events, such as passaging, which results in generation of double strand breaks.

Thermo Fisher Scientific recently launched a supplement which can be used in post-thaw recovery, as well as for support of cells during passaging conditions-RevitaCell™ Supplement (Cat #A26445-01). NOTE: It should only be added to the culture medium for the first 24 hours post-thaw or post-split followed by feeding with unsupplemented medium for the remainder of time in culture. RevitaCell™ Supplement contains a specific ROCK inhibitor coupled with compounds having antioxidant and free radical scavenger properties. In general, addition of antioxidants to the culture medium has been shown to improve genome stability by reducing the ROS within the PSC during a range of processes (Stem Cell Reports 2:44-51, Scientific Reports 4:3779).