In January, Dr. Carolyn Givens and I attended a meeting in Hawaii organized by the American Board of Bioanalysts (ABB). This organization board certifies and licenses embryologists, andrologists, and a number of other laboratory specialists in the United States. Our meeting was under the direction of the College of Reproductive Biology, a special interest group within the ABB and for which I am the immediate past Chair.
The meeting was small and intimate, a situation always welcomed among reproductive biology professionals. The location allowed for good interaction with embryologists from Japan who have always been a great source of ideas and innovation within our specialty.
In fact, the highlight of the meeting was a series of videos shown by Dr. Yasuyuki Mio from the Mio Fertility Clinic in Yonago, Japan. He was able to take time-lapse cinematography of human embryos in culture, and as a result reported some novel observations on how oocytes fertilize and how embryos develop. The actual moment of sperm entry into the oocyte was recorded and it was possible to see that human oocytes form a fertilization cone (a membrane that helps bring the sperm into the oocyte), shortly after sperm entry. The events that follow (2nd polar body extrusion, which is the egg extruding a set of chromosomes, and pronuclear formation, alignment of the nuclei from the egg and sperm) occurred as expected, but for the first time the male and the female nuclei could be distinguished from each other.
After fertilization, the embryos were seen to change dramatically as they developed. In particular, they appeared more disorganized and untidy immediately after a cell division event and more symmetrical and organized several hours later. This discovery has implications for those embryos that sometimes may appear poorly. It suggests that they may look better later in the day when they are clear of the cell division process. Another important observation regarding blastocysts, is that those that develop 2 inner cell masses (ICM: the precursor cells of the fetus) do so in a predictable way. At PFC, we avoid using embryos with two ICMs whenever possible, as they are likely to lead to the formation of identical twins. A normal embryo should have only a single ICM. Currently, it is possible that one of the ICMs may be small enough to avoid detection. The observation was made that the fine cellular bridges within the embryo cavity appear to correlate to the presence of an extra ICM.
Another notable presentation was that of Dr. Tetsunori Mukaida, of Hiroshima HART Clinic, on sperm morphology. He demonstrated that observing sperm under ultra-high magnification can show structural defects that are not always visible when using standard microscopes. While magnifying sperm thousands of times has its difficulties, Dr. Mukaida reported that sperm with subtle physical defects have a much lower chance of making an embryo that can become a baby. Sperm that are close to perfect in size, shape and structure are difficult to find in any sperm sample and it can take hours just to find a few ideal sperm. However, the extra effort may be worthwhile, especially in patients that have had a previous IVF cycle where the embryos did not develop well or implant after transfer. PFC is currently looking into this technology and we will report more details in a future issue of Fertility Flash.
Attending meetings like this and keeping up with the latest developments in our field is an important part of the culture at PFC. We share the load of traveling to educational events and are always excited to bring home ideas and thoughts to share with our colleagues. PFC is committed to implementing the latest technology and innovations to maximize pregnancy rates for our patients. We will continue to stay updated with all of the research and development in our specialty.
Both Dr. Givens and Dr. Conaghan contributed to this article.
|Joe Conaghan, Ph.D., HCLD is PFC’s laboratory director. Dr. Conaghan is internationally recognized for his work on improving embryo culture conditions. His interests include developing programs for the treatment of severe male factor infertility; diagnosis of genetic disease in embryos; and improved embryo culture.|
|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.|