Well sorry I have to say this but how long is a piece of string! Specifically, it is dependent on the cell type you want to make, fpr example if you require hepatocytes then 15 to 17 days for iPS or ES. While if you want to make say motor neurons or glia this takes months. In addition are there specific differentiation procedures in place? So need you really first to address what you want to make in the first place. Cheers

Gareth

Thks gareth, it was rather a general question. I was curious to know how close we are to use these models into standardised models for example in safety testing. let's reduce the possibilities of answers: Which of these cell types could be ready for standardisation/validation? if not, how far are we aiming before it is possible?

Hi Francois,

I think some cell types are already fairly standardized and available for drug/toxicity screenings, such as cardiomyocytes or neurons from pluripotent stem cells (see Cellular dynamics products for examples...)

thanks Julien. In order to push my luck, do you know any reference for test guidelines? US, european, OECD?

best

fr

Sorry, I have no idea about it...Good luck

Hi Francois,

there is the validated embryonic stem cell test (EST) published in nature protocols (http://www.nature.com/nprot/journal/v6/n7/full/nprot.2011.348.html). This test is validated for P19 ECC (differentiation in cardiomyocytes) and 3T3L-1 preadipocytes. I worked with both and especially the 3T3L-1 preadipocytes are really easy to handle. The P19 ECC protocol is more time consuming and needs at least some experience in stem cell work, I would say.

Good luck!

many thanks Kristina! i will look at it.

Hi Again, well there is one other factor to take into account that has been noted by a number of research groups aswell as our own. But basically each hES or hiPSC line is fundamentally different not massively but in terms of its ability to go down a particular

lineage. Doug melons group published a little paper stating this see:

http://www.nature.com/nbt/journal/v26/n3/full/nbt1383.html

So some lines are better for making neurons other for cardiomyoctyes etc. This is why we tend to see small studies because of this. But with time we will be able to cherry pick our iPS clones based on the profiles and predict lineage commitment.

cheers

gareth