I want to use Cryotop technique for embryo vitrification. Did you have any experience about this issue? I know that Kitazato has commercial kits for this aim. Have you used this product? Or can we prepare vitrification solutions or straws for this aim?
Thank you for your answers...
We have a good experience with using Cryotop straws and Kitazato medium since several years ago. The survival rate is about 90% with embryos frozen at day +3 and blastocyst. We buy directly the kit better than prepare yourself.
I send you attached the protocol in the case you need it.
Kind regards
Rocio
Hi Rocio,
Thank you for your answer and sharing. However, I have extra questions. How many embryo can I vitrify for each kit? And which kind of system or kit did you use (open or closed cryotop)?
I think I will not need to buy cooling rack and sealer from kitazato, If I prefer open Cryotop system. Is it true?
My best wishes,
Umut
Hello,
I use Cryotop of open-type. But I think that the use of chemically defined medium and closed system are desirable for the transfer of embryos in order to prevent the spreading of diseases. Therefore Kitazato medium was a good candidate for transfer of embryos. I hear that that a synthetic serum is used for the kit.
I think a vitrification up to 6 embryos is desirable. Dr.Ushijima vitrified 10 together. https://www.jstage.jst.go.jp/article/jrd/50/4/50_4_481/_pdf
Best regards,
Nobu
Hi Umut,
We use a intermediate system: semi-closed system, that is also from Kitazato. We have tested several media and systems, and Kitazato gets the best resaults.
Each kit could be used for 3 straws. We vitrified a maximum of 4 embryos for each straw for the best survival, but, however, you can use optimize the kit and use more than 3 straws (is depending of the embryologist skill).
And, finally, I agree with you. You do not need to buy the cooling rack and the sealer from Kitazato.
Best regards
Rocío
In our experience, Kitazato vitrification and warming solutions have been producing consistently excellent survival rates since 2007. It is not only the cryotop, the solutions and protocol plays important roles in survival. We have been using open system. In house prepared solutions are prone to more variation and quality control issues which I do not recommend when superior products are commercially available. You can economize the product by reducing the volume of vitrification drops. They are viscous solutions and do not evaporate rapidly. The number of embryos per cryotop should be decided based on the number of embryos for transfer. Vitrification of smaller number is better than freezing many per cryotop.
We are the same experience as Murid Javed. We have been working with open system until one year ago and works well.
Rocío
Hello
We used Cryotop of open-type. we prepared solutions ourselves but used Kitazato Cryotop. you can vitrified 5 embryos for each straw for animal embryos. your skill is very important and affected on viability and developmental rate of embryos.
Hello
we didn't use Kitazato kit but used Kitazato Cryotop. we prepared solution ourselves. you need skill and speed to loading 5 embryos for each straw.
Two steps are very time sensitive and critical for survival of embryos.
1) The second step of vitrification that has to be completed in 60-90 seconds and the media volume has to be controlled.
2) The first step of thawing in solution 1, in which embryos stay only for 1 minutes.
If for any reason, there is delay in any of the above steps, the survival will be affected. Loading more embryos on each cryotop poses risk of delays in any of the above steps unless some one develops super expertise in loading and finding more than 4 embryos on one cryotop.
Some times the embryos stick to the cryotop and it takes some effort to dislodge them.
I understand the cost of the cryotop will push in certain situations to load more embryos, however, it is then trade of between survival and economy.
In human clinical practice, survival is top priority, therefore, either one or maximum two blastocysts per cryotop are recommended. For cleavage stage embryos, 2-3 are recommended per cryotop.