Cryopreservation of ovarian tissueThe highest success rates in Europe
Our life is very unpredictable and sometimes it brings unpleasant surprises, such as a variety of diseases, including cancer. The rapid development of oncology became the impetus for the development of various methods of preserving genetic material of women. Increasingly, there are people who at a young age have undergone cancer, recovered and now lead normal everyday life. They are all healthy people tend to have a complete family, kids. However, an obstacle often occurs as a result of the treatment. All the irradiation and chemotherapy primarily affect different organs most of all the reproductive ones. Until recently, medicine often faced with the problem when a young girl of 25 years who recovered after oncological disease, had exhausted all her follicular potential, bringing inability to have her own genetically relative children.
Cryopreservation of ovarian tissue process
The risks of premature menopause and infertility reach 53-89% depending on the age of patients, type of disease and methods of treatment that has been used.
There are several ways to preserve reproductive function of women with malignant diseases, including cryopreservation (freezing) of oocytes, embryos, and ovarian tissue.
Cryopreservation is the process of freezing of gametes (sperm and eggs) and embryos of good quality storage indefinitely.
Methods of cryopreservation of eggs, sperm and embryos consist in a deep freezing (up to -196 ° C) of the material in liquid nitrogen. During freezing from cells by using special solutions (cryoprotectants) is taken up water, which is detrimental to embryo and germ cells. Frozen material is stored in special containers – Dewar containers. Every piece of material is individually labeled. Embryos are stored in special straws with 1-2 embryos and sperm - in special micro tubes.
Cryopreservation (freezing) of eggs is one of the most advanced reproductive technologies worldwide. Until recently, the effectiveness of this method was being questioned because of the destruction of oocytes with ice crystals as a result of slow freezing. About 50% of oocytes were able to turn back "to life". Masahishe Kuvayamy, a Japanese scholar, Professor of Medicine, invented a new method of rapid freezing of oocytes - a method of vitrification. This method helped to achieve the 98% rate of successful thawings. According to statistics through vitrification method in the world were born more than 400 children.
If a woman who’s suffering from cancer, is worried that the results of the treatment may affect her reproductive organs, she may, unless her condition allows, due to the period at least one month during the time between the diagnosis of the disease and /or surgery and the start of exposure and/or chemotherapy, resort to ovarian stimulation, in the result of which it would be gotten 10-15 oocytes that could be frozen for the time being. Typically, 5 years after the treatment of cancer, a woman can use them. If the patient is married, on her request her oocytes can be immediately fertilized and then frozen already fertilized embryos.
Compared with women with infertility ovarian stimulation in women with cancer is quite different. The reason for this is the high level of estrogen that occurs during stimulation, which can damage the tumors that are sensitive to hormones. In order to neutralize the negative impact on tumor cells is being used additional drugs that provide blocking estrogen receptors or inhibit the formation of these hormones. Usually the cancer patient has a very little time for stimulation, that’s why protocols are being used. They allow you to start the stimulation from any day of menstrual cycle.
In case of inability to delay the start of treatment or as a consequence of the existence of a fear that ovarian stimulation could cause a worsening of cancer, there is a possibility of freezing and storage of ovarian tissue. With laparoscopy part of the ovary or one whole ovary is being removed, and the resulting tissue is being cut into thin strips and frozen.
Ovarian tissue cryopreservation is in most cases not recommended to women who:
- are >41 years old;
- have a large ovarian cyst on the ovary that is going to be cryopreserved;
- have received prior chemotherapy that has meaningfully impaired ovarian function.
Ovaries are female sex glands (paired organ). They are situated in a separate recess peritoneum and attached to the rear of peritoneal broad ligament. The size of the ovary is 3 x 2 x 1 inches and weighs about 7 grams. The main layer of the ovary is called cortical substance, which covers the inner layer - the medulla. The cortical layer contains follicles that contain eggs. In the medulla, which consists of softer connective tissue, there are numerous of blood and lymph vessels and nerves.
By dissecting the thin cortex layer away from the medulla, follicles inside the ovarian tissue can be cryopreserved for future use. Rather than cryopreservation of individual oocytes or embryos, cryopreservation of the ovarian tissue represents a more efficient way of preservation thousands of early-stage (primordial) follicles simultaneously. Moreover, primordial follicles may be less disposed to any toxic effects of cryoprotectants and the freezing process than mature oocytes. This relative antiperistasis to cryoinjury exposed by primordial follicles is likely in consequence of their smaller size, slower metabolic rates, and zona pellucida absence.
A few years after recovery those ovarian bits will be transplanted back. Transplantation can occur in several ways: transplantation of ovarian cells to the other accessible areas of the body such as the skin of the anterior abdominal wall (heterotopic transplantation) and also transplantation near the place where those pieces were taken (orthotopic transplantation).
Heterotopic transplantation provides hormones of ovarian tissue, but as for the pregnancy there should be used the assisted reproductive technologies.
Orthotopic transplantation of an ovarian autograft can allow natural pregnancy if the fallopian tubes are unscathed. Autologous orthotopic transplantation of previously frozen cortical tissue has already led to set of births of new lives and is presently the most effective from among all transplantations.
Sometimes is being used both methods. Firstly holding ovarian stimulation, through which could be received oocytes and/or embryos, then they could be frozen for storage, and secondly the next day with laparoscopy is being removed one ovary for cryopreservation. After a certain period of time using specific technologies cryopreserved egg could be "thawed", fertilized by sperm, that she wants to have a baby from, and then using IVF technology implanted in the uterus of a woman. If pregnancy occurs, a woman can bear and give birth to a baby. If for some reason a woman is not able to bear a child, then she can resort to surrogacy program, which are officially allowed in Ukraine.