SCIENCE PULSE  

Exciting Developments in the World of Pre-Implantation Genetic Screening

Figure 1. It is now possible to analyze all 23 chromosome pairs from a single embryo.

First and foremost is the error rate in determining whether there are 0, 1, 2 or more signals from any one chromosome—a problem which is compounded by the more chromosomes one wishes to count from that single cell. The error rates in some studies have been reported to be as high as 50%, making PGS by FISH essentially no better than guesswork. The second issue is mosaicism. This refers to the fact that not all cells in a Day 3 embryo are identical. Some cells may be abnormal whereas the rest are normal. The normal cells can grow preferentially and create a normal embryo by implantation. However, if the cell biopsied was abnormal, that embryo would not be transferred because of obvious concern that it may result in an abnormal early pregnancy. PGS using FISH has failed to show any benefit in improving implantation and pregnancy rates in IVF. All of these factors have seriously limited the patient population for whom we have recommended this diagnostic testing.

In the last 2-3 years, as the Human Genome Project has been completed and as more DNA-related biotechnologies have emerged to evaluate human genes, these methods are being utilized to analyze human embryos. The technology now available—the ability to analyze large numbers of genetic locations on each human chromosome, and quantify that genetic material, with the previously well-established techniques to amplify a single cell’s genetic material up to hundreds of thousands of copies—has allowed PGS to take a quantum leap forward. It is now possible to more accurately analyze all 23 chromosome pairs from a single embryo; not only to determine if the correct number of copies of each chromosome is present, but also to look at single gene mutations.

At the end of 2009, Pacific Fertility Center began working with a new biotech company called Gene Security Network, located in Redwood City (genesecurity.net). This company uses gene microarray technology to analyze amplified DNA from a single cell.

It then uses microchips to analyze 30,000 genetic loci in a quantitative manner. In addition, their unique technology allows us to compare the analysis of the embryos’ cells to the parent’s chromosomes to ensure that all the genes are being properly analyzed. It does appear that the error problems that plagued FISH technology have been overcome with this new, more sophisticated, method.

In October of 2009, Dr. Conaghan and I were invited to tour the GSN laboratory and see the technology in action. We met with David Johnson, the lead scientist at GSN, who explained the cell process; from the amplification of the DNA, to arranging the chromosomes on chips, to DNA analysis, to synthesizing the data generated with the parental genetic data to come up with a full analysis of that cell’s genome. In order to process the cells between the day of embryo biopsy (Day 3) and receive the results on the day of embryo transfer (Day 5), their technicians work around the clock in shifts. GSN has a very cold, clean room to replicate the single cells into multiple copies. They cannot allow any outside contamination, not even from a single cell. They videotape the cell duplicating process so if any errors subsequently arise, they have a video record of what the laboratory technician did. We found this to be very impressive. We also saw how the chips were coated with DNA and analyzed. We were shown the sophisticated software that generates the final report detailing the genetic makeup of each embryo from the cells in which they originated. All in all, the tour gave us great confidence in the quality control and scientific integrity at GSN.

Even with this 21st century technology, we continue to biopsy Day 3 embryos because it provides us with a 48 hours window to send the cells to the lab and complete the analysis in time for transfer. However, we have not yet found a way around the problem of mosa- icism. GSN and microarray technology appears to have largely solved the resolution error problem but it can only tell us what is in the chromosomal make-up of the single cell. It cannot tell us whether or not that cell represents what is truly going on with the rest of the embryo. We are currently looking at the possibility of biopsying Day 5 embryos. The set back would result in having to freeze these embryos due to the time constraint in analyzing the genetic material in time for fresh transfer. With all of the innovation occurring daily in the genetics field, we hope that this puzzle will be resolved.

— Carolyn Givens, M.D.

Carolyn Givens, M.D. was the first in San Francisco to successfully initiate a pregnancy using intracytoplasmic sperm injection (ICSI). She currently co-directs the Bay Area Pre-Implantation Genetic Diagnosis Program (PGD) and is director of PFC’s PGD program.

Previous Fertility Flash articles about PGS:
2 Methods of Gaining Info Prior to Implantation
PGD & PGS: Why Genetic Counseling is a Prerequisite
The Benefits and Pitfalls of PGS

Leave a Comment!

FROM US TO YOU Endometriosis and Infertility

Figure 1. A section of the ovary, including supportive cellular structures

Endometriosis was a puzzling disease when first described by pathologist Rokitansky in 1860. Though we now have a clearer understanding of some aspects of the biology of this disease, it still remains largely a mystery 150 years later.

Endometriosis affects about 5 million women in the U.S. Of women with infertility, approximately 25% are diagnosed with endometriosis. The symptoms fall into two categories:
1) pelvic pain, most significantly with menses, and 2) infertility. The definitive method to diagnose this disease is surgery. A laparoscopy is performed to obtain tissue biopsies of typical peritoneal lesions (peritoneum is the internal layer overlaying pelvic organs including the uterus, fallopian tubes and ovaries); and confirm the presence of endometrial glands in those biopsies. The American Fertility Society has created a classification scheme which grades the disease (Grade I-IV). It is important to understand that there is not necessarily a correlation between pelvic pain and the severity (or grade) of the disease. Another method for presumptively diagnosing endometriosis is with ultrasound, if the patient has endometriosis ovarian cysts (endometriomas), or with MRI if one there is endometriosis growth in the
uterine muscle layer (adenomyosis).

A diagnosis of even minimal to mild endometriosis (stage I and II) can have significant consequences on fertility success rates. A fertile 30 year old woman has about a 25% chance of pregnancy per month (fecundity rate). A patient diagnosed with minimal to mild endometriosis has about a 3% monthly fecundity rate (1, 2, 3). If surgery is performed to dissect and remove the visible endometriosis lesions, the fecundity rate improves to 6%; but this is still much lower than the 25% afforded a fertile 30 year old. If that same patient undergoes ovarian stimulation and insemination cycles, her monthly fecundity rate increases to 11% (4). If the combination of ovarian stimulation/IUI treatment is going to increase chances of pregnancy, results are usually seen within the first 3-4 treatment cycles. Undergoing additional IUI cycles is not typically beneficial, and proceeding to in-vitro fertilization (IVF) treatment would be the next step. For patients with severe endometriosis, gonadotropin/IUI therapy is of minimal assistance. Most patients with moderate to severe endometriosis (stage III and IV) will need to pursue IVF therapy (5).

Figure 2. Biopsies can determine the presence of endometrial glands in the uterus, fallopian tubes and ovaries

IVF studies from the 80s and 90s indicate that patients with endometriosis have a slightly lower chance of achieving a pregnancy than patients with other infertility diagnoses (6). With current IVF laboratory techniques and current ovarian stimulation strategies, this difference will probably disappear—but up-to-date studies are needed as proof. When assessing if the lower pregnancy rate is because of a uterine or ovarian issue, it appears that the uterus of endometriosis patients is effective in providing a supportive environment for the embryo to attach (7). However, the oocytes (eggs) from endometriosis patients, particularly those with endometriomas, seem to have some compromised quality (8). This lower egg quality seems to lead to less healthy and effective embryos, and therefore overall lower pregnancy rates.

We clearly understand that strategies of suppressing endometriosis growth by using medications such as birth control pills, Danazol, Lupron or others, does not lead to improved pregnancy rates (9). The concept of a fertility “rebound” post-medical suppression has been proven false over-and-over again. These strategies only lose potentially precious time for the patient. Similar strategies of using medical suppression post surgical removal of endometriosis also fail to improve fecundity rates. The best approach is to move forward with an appropriate form of fertility treatment as soon as the patient desires fertility.

How to treat endometriomas has been debated, but we now have some studies to guide us. Collectively these studies indicate that patients who have undergone surgery for their endmetrioma(s) have the same IVF outcomes as those where the endometrioma(s) was left alone (10). We feel that the patient’s current clinical situation should be scrutinized carefully before recommending ovarian surgery for a patient who is seeking fertility. With surgical removal of an endometioma (ovarian cystectomy), we know that the ovary where surgery is performed will have fewer eggs and less normal ovarian tissue post surgery (11). This implies that we will have a lower chance of gathering eggs in an IVF cycle. Additionally, the patient will have a greater chance of having an elevated FSH after a cystectomy procedure, especially if she undergoes cystectomies of both ovaries (11). The risk of premature ovarian failure (POF or premature menopause) for a patient undergoing cystectomies of both ovaries for endometriomas is about 2% (12).

Historically the strategy for treating endometriosis has been to surgically remove or hormonally suppress its growth with various medications. As we better understand the biology of this disease, we can use more targeted therapies which interrupt the biochemical pathways that promote the growth of endometriosis
lesions: aromatase inhibitors, estrogen and progesterone receptor blockers, angiogenesis inhibitors, etc. All of these types of medications are being studied in endometriosis patients. The future may hold some promising new medical options.

In summary, endometriosis clearly affects fecundity rates, even with minimal and mild disease. Using hormonal medications to suppress endometriosis provides no improvement in pregnancy rates, and surgical intervention provides minimal improvement. Most patients will need to pursue fertility treatment. For patients with moderate to severe disease, they most often will need to pursue IVF. For patients with endometriomas, careful consideration has to be given to all factors (age, assessment of egg quality, prior fertility treatment, etc.). The patient needs to be fully counseled prior to surgery, including risk of diminished ovarian quality (DOR) and premature menopause (POF). Patients with adenomyosis seem to have impaired implantation rates, and those with severe adenomyosis may need to consider a gestational carrier. Having a clear understanding of endometriosis as it impacts fertility, and having realistic expectations with each treatment type is most important when choosing fertility treatment options.

-- Isabelle Ryan, M.D.

Isabelle Ryan, M.D. is recognized by prestigious medical associations for her pioneering research leading to new insight into the important clinical problem of endometriosis related infertility. Dr. Ryan is medical director of PFC’s Third Party Parenting Program and Egg Donor Agency.

References

1. Jansen RP, Fertil Steril 1986; 46:141-3
2. Marcoux et al, NEJM 1997; Jul 24; 337(4):269-70
3. Parazzini, Hum Reprod 1999; 14(5):1332-4
4. Tummon et al, Fertil Streil 1997; 68(1):8-12
5. Dmowsky et al, Fertil Steril 78:750 2002
6. Barnhart et al, Fertil Steril 2002; 77:1148-1155
7. Diaz et al, Fertil Steril 2000; 74:31-34
8. Simon et al, Hum Reprod 1994; 9, 725-9
9. Hughes et al, Cochrane Database Syst Rev 2007; 3:CD000155
10. Tsoumpou et al, Fertil Steril 2009; 92, 75-87
11. Li et al, Fertil Steril 2009; 92(4):1428-35
12. Busacca et al, Obstet Gynecol 2006; (195), 4

Leave a Comment!

BOOK REVIEW The Fertile Kitchen Cookbook

Title: The Fertile Kitchen Cookbook
Subtitle: Simple Recipes for Optimizing Your Fertility
3L Publishing, 2009
By: Cindy Bailey & Pierre Giauque, Ph.D.
Online: fertilekitchen.com

Can diet influence fertility? Can altering your diet help you conceive? Is it true that you are what you eat (and so is your baby)?

At age 40 and after trying to conceive for over a year, Cindy Bailey and her husband Pierre Giauque were told that they were unlikely to conceive. With disconcerting medical test results and failure in conven tional treatment, alternative therapies seemed the best option. After trying a fertility-friendly diet, to their surprise, their son was conceived four months later.

The Fertile Kitchen is one couple’s story of overcoming the odds against conception while using common sense and easily executed measures to optimize health. Using fresh, high quality, organic ingredients, and reducing wheat and dairy; the couple developed a nutritional plan that they feel contributed to their success. These authors found that optimizing the basic ingredients for life, adjusting calories, carbohydrates, fats, and proteins into a regimen that has the potential to optimize pregnancy rates, should be considered in a given fertility plan.

Science is still catching up to medical concerns about fertility and diet. As an example of this emerging science, it is known that women with abnormal body fat levels, either high or low, suffer from lower pregnancy rates, and that improvement in body weight and body fat levels improves fertility rates…Certain types of animal protein are potentially problematic for fertility, whereas vegetable protein sources seem to carry less risk. Calorie source, simple sugar versus protein, makes a difference in treating anovulatory women. Irregular menstrual cycles can be optimized by changing diet. Omega-3 fatty acids are related to uterine artery perfusion pressures, and supplementation seems to provide some clinical improvement in these parameters. Studies are showing a role for B-complex vitamins, folic acid, and dietary fat in regulating ovulation.

It is unfortunate that some people have serious challenges to fertility that cannot be addressed with a change in diet. Diminished ovarian reserve, male factor, and tubal occlusion are problems that go beyond what can be remedied with diet alone. With that said, fertility treatment programs, regardless of the health issues, should include a healthy diet, as a good preventative measure for already healthy women wishing to conceive. The recipes in this book are easy to follow and the ingredients are amply available at most grocery stores.

Fertile Kitchen Media Kit (pdf)

— Philip Chenette, M.D.

Philip Chenette, M.D. has spent over a decade specializing in the treatment of patients with complex infertility diagnoses, especially in women with decreased ovarian reserve and women over 40.

Leave a Comment!

Thank you for your interest in subscribing to Pacific Fertility Center’s free monthly newsletter. In order to better protect your privacy, we have a new secure subscription/log in form. We respect your privacy: Your email remains confidential and will not be shared or sold.
Please click here to change your subscription preferences.

-- Best regards from all of us at Pacific Fertility Center.