LET’S TALK ABOUT VITRIFICATION…

EGG AND EMBRYO FREEZING – VITRIFICATION
The techniques that are performed in an embryology laboratory are progressing with impressive rhythms. Everything new, adds either a larger and or a smaller step in achieving more impressive results in the field of Clinical Embryology. After the Intracytoplasmic sperm injection (ICSI), the next great advancement in embryological techniques is the oocyte and embryo Vitrification (fast freeze-Vitrification).
VITRIFICATION – WHAT IS IT ?

Vitrification is a cryopreservation protocol, in which high concentration of cryoprotectant is used for a short time period, while a temperature reduction is achieved at the same time by direct immersion of the oocytes or the fertilized oocytes  in liquid nitrogen surrounded by an extremely small amount of cryoprotectant. 

This leads in avoiding possible toxic effects from high concentrations of cryoprotectants on oocytes or embryos, while protecting the cytoplasm from intracellular crystal structures (ice crystals). During vitrification, the molecules move less and eventually create a stable structure to temperatures below -100 C, turning the biological material “glassy” avoiding its literally “freezing” and ice formation.
This technique is particularly fast, with great importance on details and requires high technical skills of the embryologist.
The replacement of slow freezing by Vitrification improves spectacularly the efficiency of cryopreservation, providing oocyte and embryo survival rates after thawing, which exceed the 95% -98%.
WHERE IT IS USED
Due to the high survival rate after thawing, oocyte-embryo vitrification is beneficially applied to:
EGGS

1. For oocyte cryopreservation of women who do not wish  to have a baby yet (social freezing). With this method the oocytes are “reserved” in the age of the woman during freezing, no matter how many years after will be thawed. This can avoid the negative effect of time on the quality of woman’s oocytes.

2. For oocyte cryopreservation of women that undergo treatment that might adversely affect the quality of their eggs, such as radiation, chemotherapy, etc.
1. To preserve oocytes in cases where finding husband’s/ partner’s sperm on the day of oocyte retrieval is not possible (azoospermia, sperm collection weakness etc.).
2. Egg Donation Bank founding.
2. To collect sufficient number of oocytes in cases of women with poor drug response (poor responder) before performing fertilization (ICSI) and embryo transfer. In this way, the couple benefits because it is charged the cost of ICSI only once.
EMBRYOS
1.For cryopreservation of super numerous embryos after embryo transfer, whose development and morphology  satisfy the cryopeservation criteria set by  the Embryology Laboratory.
2. For the cryopreservation of all embryos after IVF,  when the hormonal profile of the woman on the day of embryo transfer is not consistent with satisfactory success.
VITRIFICATION REQUIREMENTS 
As mentioned above, vitrification is a highly demanding technique. When applying Vitrification a strict Protocol is required to be followed, with absolute respect to the details, precise movements and high speed in its operation. The laboratory equipment required is neither complicated nor expensive. On the contrary, the reagents and the consumables used have a fairly high cost.
EGG AND EMBRYOS CRYOBANKING
After cryopreservation, oocytes and embryos, are kept in special  tanks (cryotankers), filled with liquid nitrogen. The cryotankers are particularly reliable and safe, since they are provided with external signs of the internal level of liquid nitrogen and the temperature. They also have audio and visual alarm if any of the parameters mentioned above (liquid-nitrogen temperature level) falls below certain limits. They can also be connected to a central control system that informs via sms the responsible Embryologist if any of the above has gone out of accepted limits.Last but not least, in our daily Embryology Laboratory quality control practice, the containers are checked by the responsible for this task embryologist.
Inside the cryopreservation containers, each couple’s embryos or oocytes are kept in a perfectly defined place, which is exclusive for each case during cryopreservation. The vitrified embryos or oocytes are additionally labeled with the name of the woman, the freezing date and the unique code supplied with the woman in our unit. Furthermore, each case’s place is written in the folder of the couple/ woman, in cryopreservation file in the Embryology Laboratory, and electronically in the Database of ASSISTING NATURE.
Oocytes and embryos are therefore extremely safe regarding keeping them intact and maintaining their identity.
Biological limit for cryopreservation time does not exist, vitrified oocytes and embryos can be cryopreserved for as long as it is necessary without any difference in survival or quality after thawing.
On the contrary there is Legal restriction and the couples / women should be informed prior to freezing and sign consents. It is the couple’s/woman’s responsibility to communicate every year with the Cryopreservation Bank, to inform the responsible Embryologist of their intentions about their cryopreserved biological material (continue to be maintained, to be destroyed, to be donated, used for research-therapeutic purposes).
ASSISTING NATURE RESULTS

The ASSISTING NATURE pregnancy rate , after thawing and transfer of cryopreserved embryos is particularly high. Specifically, according to the statistics of our Unit, we calculated/ and subsequently announced to EL.E.Y.I.A/ this amounts to 59% !! The survival rate of thawed  embryos,  calculated for the first half of 2015 reached  95% !!  Finally let me promise the continuation of providing  high quality services  in order to assisting couples making their dream come true.