By the end of the year we will have started a new and very exciting research project in our lab. We have partnered with a company called Incept Biosystems (www.inceptbio.com) to do a clinical trial of a new embryo culture system called microfluidics.
The traditional culture dish with medium droplets under oil as described by Brinster, R.L., 1963, Exp. Cell Res., Vol. 32
This involves culturing embryos in very small volumes of culture media inside a chip specifically designed for this purpose. Tiny pumps regulate the flow of culture medium in and out of the chip without causing the embryos to move around.
The traditional vessel for embryo culture is the petri dish, where small droplets of culture medium are overlain with a highly purified mineral oil. The culture medium, regulated in much the same way as pharmaceuticals, is one of the most highly tested and expensive components of the IVF laboratory operation. We typically make droplets of medium that are in the 50-200µl size range, and the oocytes or embryos are placed in the droplets for 24-48 hours at a time. This is a static culture system where nutrients are depleted by the developing embryos and waste products (e.g. ammonia from amino acid breakdown) accumulate over time. The droplets are large enough to make sure that the supply of nutrients is more than adequate and that waste is diluted to the point of not harming the embryo in any way. The embryos are changed into fresh medium at least every 48 hours.
This system for embryo culture has been in use since human IVF began in the late 1970’s and early 1980’s. It was actually developed in the early 1960’s by a pioneer of mouse embryo culture, Dr Ralph Brinster, at the University of Pennsylvania. Some early human embryologists cultured embryos in small test tubes without the mineral oil, but nowadays, despite the age of this technique, it is very unusual to find a facility that does not use the droplets under oil method. After 45 years, perhaps it is time for a change?
A microfluidic system for embryo culture has been in development for over 5 years at the University of Michigan in Ann Arbor. Professor Gary Smith combined the talents of his graduate students in physiology with those of engineering students and came up with a device that has had outstanding results with growing mouse embryos. Professor Smith is no stranger to IVF, as he was the director of the University’s IVF Laboratory for many years and he was instrumental in designing and testing the vitrification system that we now use to preserve oocytes and embryos. He solicited venture capital to start Incept Biosystems with the intent to bring microfluidics into human IVF labs. Incept Biosystems were onsite at PFC during the last week of October to train our embryologists on the use of the system. We did several trials with mouse embryos to achieve proficiency with the system and then we will actively recruit patients to enroll in a clinical trial using the system.
The clinical trials are being run at 3 centers in the US. In addition to PFC, patients will participate at the Fertility Center of San Antonio and at Southeastern Fertility Center in Charleston, South Carolina.
A schematic of a microfluidic embryo culture device with fresh medium in blue and spent medium in red. The embryo is contained at the base of the chamber, where the blue medium ends.
Patients that are asked to participate will have to consent to the study, where their embryos will be divided into 2 groups for culture in the microfluidic device and in the traditional petri dish. The culture media will be the same for all the embryos, but half will be in a replenishing media current (microfluidics) and half will be in our traditional static culture.
Microfluidics has had impressive results with mouse embryos where it significantly increased rates of development and implantation over those for embryos grown in static culture. Cell numbers for the microfluidic embryos were almost twice as high as for traditional culture (110 vs. 65), and pregnancy rates from transferred embryos were increased by 22%. Incept Biosystems have tested the new technology extensively and have been able to obtain surplus IVF embryos donated for research for human trials. There are some nice videos on their website that showcase the equipment and procedure, and detail the mouse embryo results. Professor Smith presented the results and won the prize paper at the 2008 American Society for Reproductive Medicine (ASRM) meeting (Smith et al., 2008, Fertility and Sterility, Vol 90, pages S1-S2), and these results will soon be published in a peer reviewed journal.
We will be asking for participants to join the study, beginning in November and continuing for 2-3 months. This is a short study requiring enrollment of only 20 patients, but a larger study is planned for next year subject to favorable outcomes here. If you are interested in the study and would like more information, please ask your physician at your next visit.
–Joe Conaghan, Ph.D, HCLD
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.
