Human eggs grown to maturity in the lab first time could unlock future fertility options

image credit: Prof David Albertini

In an extraordinary scientific feat, researchers were successful in growing human oocytes from the earliest follicular stage in the laboratory in just 20 days instead of 5 months in the body. The eggs fertility potential is unknown yet, and it remains to be seen whether they can produce healthy babies. 

The study was carried out in collaboration with the Royal Infirmary Edinburgh, The Center for Human Reproduction in New York and the Royal Hospital for Sick Children in Edinburgh, and published January 2018 in Journal of molecular human reproduction.

This process of oocytes maturation in lab could find potential applications in fertility preservation of cancer patients during the chemotherapy treatments. Immature eggs recovered from patients’ ovarian tissue could be matured in the lab and stored for later fertilization without the fear of reintroducing cancer.

Professor Evelyn Telfer from School of Biological Sciences said, “Being able to fully develop human eggs in the lab could widen the scope of available fertility treatments. We are now working on optimizing the conditions that support egg development in this way and studying how healthy they are. We also hope to find out, subject to regulatory approval, whether they can be fertilized.”

Till now researchers have successfully produced live offspring in mouse from in vitro grown (IVG) oocytes from primordial follicles. They have also grown human oocytes from secondary/multi-laminar stage to obtain fully grown oocytes capable of meiotic maturation.

However, this is the first report of in vitro complete human oocyte growth from immature primordial/unilaminar follicles using two-step culture system.

A series of magnified images show human eggs in development stages. Prof. Evelyn Telfer and Dr. Marie McLaughlin/University of Edinburgh/Handout via REUTERS

The scientist obtained fresh ovarian cortical pieces of approximate size 5 mm × 4 mm from women undergoing elective cesarean section. Fragments were cultured for 8 days according to the institute predetermined protocols.

Follicles ranging in diameter from 100–150 μm were dissected for further isolated culture. After about 8 days cumulus-oocyte complexes (COCs) were retrieved by gentle pressure on the cultured follicles. These COCs were further cultured for 4 more days when complexes containing oocytes >100 μm diameter were selected for in vitro maturation (IVM) in SAGE medium and subsequently fixed for analysis.

Confocal immuno-histochemical analysis of oocytes more than 100 μm diameter showed the presence of a Metaphase II spindle confirming that these IVG oocytes had resumed meiosis but their developmental potential is unknown.

Other scientists are looking at this process with great concern because of the shortened maturation process and lack of genetic analysis of the matured egg.

Telfer agrees that much work needed to be done and said, “We had no great expectations. To see at least one [egg reaching maturity], we thought, ‘Wow, that’s actually quite incredible.’”

The eggs fertility potential is unknown yet because of lack of regulatory approval, and even if they have can be fertilized much research is needed to see whether they can produce healthy babies.

But, the study has given new insights on human egg development that could be very useful in fertility treatment and regenerative therapies.

Her team is working on improving the process and getting an approval from the United Kingdom’s Human Fertilization and Embryology Authority—to try fertilizing the lab-matured eggs to create human embryos.

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University of Edinburgh press release

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Uterine transposition: A novel option to preserve fertility in patients requiring pelvic chemoradiation

Courtesy: University of Queensland.

Uterine transposition is an interesting and novel technique not ever reported in literature. This is the first case report of uterine transposition and technique published in August issue of Journal Fertility and Sterility.

All gynecologists are familiar with transposing ovaries to preserve fertility and avoid premature menopause in patients who require radiation treatment to the pelvis for cervical cancer.

Dr Reitan Ribeiro from Brazil reports the case of a 26-year-old woman diagnosed with rectal adenocarcinoma located 5 cm from the anal margin. The patient was young and did not have any children and wanted to preserve her fertility.

Dr Ribeiro offered the patient a repositioning of the uterus outside the pelvic cavity called along with the ovaries outside the pelvic cavity, to save them from harm due to pelvic radiation.

The maximum tolerated radiation dose for the ovaries is 15 Gy; for uterus and cervix it is 20 Gy to 30 Gy. But, the radiation dose for curing rectal cancer is significantly higher and is approximately 50 Gy, at which all the pelvic organs will be certainly damaged.

After the radiation treatment was complete the uterus was repositioned back into the pelvic cavity.

The entire procedure was carried out laparoscopically (key hole surgery) without a big abdominal incision. The basis for this procedure is that the blood vessels to the ovaries provide also good blood supply for the uterus at the same time.

The uterus and ovarian functions were preserved as evident by 2 menstrual period that began after 2 weeks of repositioning the uterus back and the cyclic ovarian hormonal variation was maintained at the time of neoadjuvant therapy.

At per speculum examination at 6 weeks the cervix was entirely normal looking and at 18 months follow up the uterus appeared to be normal.

The paper was also presented by Dr. Ribeiro at Society of Gynecologic Oncology 2017Annual Meeting from 10 to 14 March in Washington D.C.

He did acknowledge that further studies are warranted to establish the safety and efficacy of the procedure. The spread of tumor to a location not easily amenable to treatment was a major concern.

Dr Riberio and colleagues have launched a Uterine Transposition: Feasibility Study  and will shortly start recruiting patients.

This prospective nonrandomized multicenter phase I study, will evaluate the feasibility of performing uterine transposition before chemoradiation for rectal cancer and uterine reimplantation after the treatment. 

The authors concluded that, “Uterine transposition might represent a valid option for fertility preservation in women who require pelvic radiotherapy and want to bear children.” 

Related link: Ovarian Transposition: A novel laparoscopic surgical method video by Cleveland Clinics.

https://obgynupdated.blogspot.com/2017/03/ovarian-transposition-novel_17.html

Ovarian Transposition: A novel laparoscopic surgical method video by Cleveland Clinics.

First described in 1958, ovarian transposition is a great way to move ovaries away from the radiation field to preserve fertility and prevent early menopause in reproductive age women undergoing pelvic or low abdominal radiation therapy. These women may also be scheduled to receive chemotherapy, which has low gonadotoxicity after the radiation therapy.

The vascular pedicle remains intact in transposition vs. transplantation. Ovarian stimulation and oocyte retrieval can be easily performed later when the patient desires fertility.  

Oocytes are highly sensitive to radiation and 16 gray (Gy) of radiation will deplete the entire oocyte pool in a 20-year-old.

The most common cancers which require low abdominal radiations are rectal and anal cancers.

A recent article published in forthcoming issue of Fertility and Sterility describes and demonstrate novel surgical method of laparoscopic ovarian transposition. This is a minimal invasive approach in which the ovary is tunneled through a peritoneum.

A 29-year-old female was diagnosed with rectal cancer, the patient underwent laparoscopic ovarian transposition of one ovary followed by ovarian decortication for ovarian tissue freezing of the contralateral ovary, both performed in one laparoscopic surgery, before further chemotherapy and radiation.

The procedure was performed to maintain the ovarian blood supply retroperitoneally and prevent the ovarian vessels taking a sharp turn in pelvic cavity.  

The laparoscopic ovarian transposition has a success rate of 88.6% for preservation of ovarian function as seen from the levels of gonadotropin levels after cancer treatment.

A systematic review and meta-analysis of published in Journal of Ovarian Research concluded that it significantly preserves ovarian function with minimum risk of metastasis to the ovary even in gynecological malignancies.

Here is the video presentation of the surgical procedure by Cleveland Clinics. 

Is it possible to protect the gonads during chemotherapy?

 It is estimated that in  USA about 843,820 new cases of cancer all site would be diagnosed in women in the year 2016 out of which 89,140 will be younger than 45 years of age.

As a result of improved knowledge and increased health awareness combined with increased availability of screening tests and healthcare resources many cancers are now diagnosed at a younger age than before.

According to WHO the 5 most common sites of cancer in women are breast, colorectal, lung, cervix, and stomach cancer.

The treatment for cancers diagnosed at early stage is more specific, less destructive and results in more Disease-free survival (DFS) and progression-free survival (PFS) resulting in improved quality of life.

When the rapidly dividing cancer cells are targeted with chemotherapy/ radiotherapy, the germ cells in gonads are also affected and are destroyed.

As a result older women with decreased ovarian reserve may end up in ovarian failure, losing the capacity to reproduce while younger women become hypoestrogenic.

According to the International guidelines on fertility preservation it is recommended that the physicians address the issue of fertility preservation with all patients of reproductive age as early as possible before initiating the treatment and keeping them informed about all the options.

As recommended by the American Society of Clinical Oncology and the European Society for Medical Oncology, sperm cryopreservation and embryo/oocyte cryopreservation are standard strategies for fertility preservations in male and female patients, respectively.

Other strategies (e.g. pharmacological protection of the gonads and gonadal tissue cryopreservation) are still at experimental stage due to lack of large data and guidelines..

This Systematic Review and Meta-analysis by Elgindy E et al published in the December issue of Journal of Obstetrics and Gynecology aims to estimate whether gonadotropin-releasing hormone (GnRH) analog administration during chemotherapy can protect against development of ovarian toxicity.

Many studies have earlier evaluated the use of GnRH to preserve the endocrinological and biological function of the gonads in cancer chemotherapy/Radiotherapy with conflicting results.

Meta-analysis by Shen YW et al published in Journal of Oncotargets and Therapy (2015 Nov 13;8:3349-59) did show that  GnRH agonists cotreatment with chemotherapy in premenopausal women with breast cancer plays a beneficial role in resumption of ovarian function, with a higher rate of resumption of menses. However, treatment with GnRH agonists does not appear to exhibit its protective effects in fertility.

Another Meta-analysis Wang C et al in PloS One(2013 Jun 21;8(6):e66360. Print 2013) also concluded a potential benefit of GnRH cotreatment with chemotherapy in premenopausal women, producing higher rates of spontaneous resumption of menses.

Both the trials reported an increased pregnancy rate, however both these meta-analysis included trials with patients having breast cancer only.

A total of 10 RCTs with 907 women were included in the analysis comparing resumption of ovarian function between use of GnRH analogs plus chemotherapy with chemotherapy without GnRH the analogs.

The primary outcomes were resumed ovarian function at the longest follow-up after the end of chemotherapy. Secondary outcomes were evaluating ovarian reserve parameters and pregnancy.

Resumption of menstrual cycles was observed in 320 of 468 in in GnRH analog arm and 263 of 439 in the chemotherapy alone arm, which did not reach statistical significance.

No significant difference was observed when the data was analyzed according to different type of cancer, age below 40 vs above 40 years.

Other parameters of   ovarian capacity (baseline follicle-stimulating hormone level, anti-Müllerian hormone level, or antral follicle count) and pregnancy rates upon completion of chemotherapy also did not show a significantly difference between the two arms.

On the basis of this meta-analysis, it was seen that GnRHa co-treatment had no significant impact on rates of resumption of ovarian function among reproductive-age women undergoing chemotherapy.

National Comprehensive Cancer Network (NCCN) guidelines have been updated to acknowledge the use of LHRHa in preventing chemotherapy-induced ovarian failure of hormone receptor negative breast cancer patients.

However, ovarian suppression with GnRH during chemotherapy is still considered an experimental strategy to preserve fertility by some international guidelines due to both the uncertainty regarding the efficacy of this strategy and the absence of data on pregnancies and long-term ovarian function.

References:

http://www.who.int/mediacentre/factsheets/fs297/en/

http://www.cancer.gov/about-cancer/what-is-cancer/statistics

http://www.cancer.org/acs/groups/content/@research/documents/document/acspc-047068.pdf

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4700580/

http://www.ncbi.nlm.nih.gov/pubmed/26728489

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4700580/

http://www.ncbi.nlm.nih.gov/pubmed/26622183

http://www.ncbi.nlm.nih.gov/pubmed/26241272