science

Ovarian tissue cryopreservation

Ovarian tissue cryopreservation is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Ovarian tissue cryopreservation rather than just read about it. In short: Ovarian tissue cryopreservation is cryopreservation of tissue of the ovary of a female. Indications Cryopreservation of ovarian tissue is of interest to women who want fertility preservation beyond the natural limit, or whose reproductive potential is threatened by cancer therapy, for example in hematologic malignancies or breast cancer.

Key takeaways

Ovarian tissue cryopreservation belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Ovarian tissue cryopreservation to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Ovarian tissue cryopreservation from memory before moving on to harder problems.

Reference excerpt

Ovarian tissue cryopreservation is cryopreservation of tissue of the ovary of a female.

Indications Cryopreservation of ovarian tissue is of interest to women who want fertility preservation beyond the natural limit, or whose reproductive potential is threatened by cancer therapy, for example in hematologic malignancies or breast cancer. It can be performed on prepubertal girls at risk for premature ovarian failure, and this procedure is as feasible and safe as comparable operative procedures in children.

Procedure

The procedure is to take a part of the ovary and carry out slow freezing before storing it in liquid nitrogen whilst therapy is undertaken. Tissue can then be thawed and implanted near the fallopian, either orthotopic (on the natural location) or heterotopic (on the abdominal wall), where it starts to produce new eggs, allowing normal conception to take place. A study of 60 procedures concluded that ovarian tissue harvesting appears to be safe. A study has also concluded that culturing a thawed fetal ovarian tissue for a few days before transplanting can be beneficial to the development of follicles. Strips of cortical ovarian tissue can also be cryopreserved, but it must be re-implanted into the body to allow the encapsulated immature follicles to complete their maturation. In vitro maturation has been performed experimentally, but the technique is not yet clinically available. With this technique, cryopreserved ovarian tissue could possibly be used to make oocytes that can directly undergo in vitro fertilization.

Potential for Pregnancy Women with malignant diseases that undergo treatment utilizing irradiation or gonadotoxic drugs, have an increase probability of losing ovarian function resulting in infertility. The ovarian cortical tissue harbors majority of the ovarian pool of follicles. Once a patient is cured from their malignant disease, the tissue can be thawed and then transplanted for the possibility of restoring ovarian function. Following auto-transplantation, patients showed resumption of ovarian activity to include the first menstruation at 14 to 25 weeks, and follicular development 8 to 21 weeks.

Risk of cancer recurrence For autotransplantation of cryopreserved ovarian tissue in cancer survivors, metastases have been repeatedly detected in ovarian tissue obtained from patients with leukemia, as well as in one patient with Ewing sarcoma. Ovarian tissue autotransplantation may pose a risk of cancer recurrence in patients with colorectal, gastric and endometrial cancer. However, no metastases have been detected in ovarian tissue from lymphoma and breast cancer patients who have been undergoing ovarian tissue cryopreseration.

History The first transplant of cryopreserved ovarian tissue was performed in New York by Kutluk Oktay in 1999, but it did not restore menstrual cycles to the patient. In 2004 Jacques Donnez in Belgium reported the first successful birth from frozen tissue using a protocol developed in Roger Gosden’s laboratory, where Oktay had studied. In 1997 samples of ovarian cortex were taken from a woman with Hodgkin's lymphoma and cryopreserved by slow freezing (Planer, UK) for banking in liquid nitrogen. The patient had premature ovarian failure after chemotherapy. In 2003, after freeze-thawing, orthotopic autotransplantation of ovarian cortical tissue was done by laparoscopy and five months after reimplantation regular ovulatory cycles were reinitiated. Eleven months after re-implantation a viable intrauterine pregnancy was confirmed, which resulted in the delivery of a healthy baby. Donnez's claims have been challenged because there was no absolute proof if the mother was infertile before treatment. However, Sherman Silber in St. Louis, Missouri, and another of Gosden's collaborators, Dror Meirow at the Sheba Medical Center in Israel, and subsequently others have proven beyond doubt the technique is effective. Healthy babies of both genders have been born. The first birth following transplantation of ovarian tissue stored at a central cryo bank and transported overnight has been achieved by centers of the Fertiprotekt network in Germany 2011. This demonstrated that ovarian tissue can be stored centrally in specialized centers.

References

See also Tissue cryopreservation Cryopreservation of testicular tissue

Illustrations

Worked examples

Example 1 — a first encounter with Ovarian tissue cryopreservation

Start with the simplest possible case. Write down what Ovarian tissue cryopreservation claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Ovarian tissue cryopreservation before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Ovarian tissue cryopreservation ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Ovarian tissue cryopreservation

In research: Ovarian tissue cryopreservation appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Ovarian tissue cryopreservation in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Ovarian tissue cryopreservation is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cryogenics, Cryopreservation, Obstetrical procedures, so understanding it makes those chapters shorter.
In everyday life: Look for Ovarian tissue cryopreservation outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Ovarian tissue cryopreservation in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Ovarian tissue cryopreservation means in your own words.
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Frequently asked questions

What is Ovarian tissue cryopreservation in simple terms?

Ovarian tissue cryopreservation is cryopreservation of tissue of the ovary of a female. Indications Cryopreservation of ovarian tissue is of interest to women who want fertility preservation beyond the natural limit, or whose reproductive potential is threatened by cancer therapy, for example in he…

Why does Ovarian tissue cryopreservation matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Ovarian tissue cryopreservation?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Ovarian tissue cryopreservation.