Lasers in the IVF lab
IVF is one of modern medicine's dramatic success stories. After a considerable amount of experience, lasers have been successfully integrated into routine IVF practice, and are now found in most advanced and well-equipped IVF (In Vitro Fertilization) labs the world over.
Lasers in the IVF (In Vitro Fertilization) lab
IVF is one of modern medicine's dramatic success stories . This is especially because of the phenomenal advances which have occurred in the IVF laboratory , and infertility treatment today is largely based on our ability to manipulate gametes and embryos in vitro in the IVF laboratory. However, advances in IVF (In Vitro Fertilization) are now limited by technical proficiency, which emphasizes why we need to apply new technology which allows for greater precision in gamete handling.
Given the fact that eggs, sperms and embryos are all microscopic, it is hardly surprising that one of the successful advances in recent times has been the introduction of lasers in the IVF lab, since lasers allow the embryologist to deliver a controlled amount of energy at a specified spot with exquisite precision. After a considerable amount of experience, lasers have been successfully integrated into routine IVF practice, and are now found in most advanced and well-equipped IVF (In Vitro Fertilization) labs the world over. The advantages of a laser are multiple - it is precise; atraumatic, and non-contact , which means there is no need to touch the egg or embryo when using the laser. At Malpani Infertility Clinic, we use the Saturn IVF laser manufactured by Research-Instruments, UK, one of the pioneers in this field.
The initial concerns regarding the safety of the laser have now been put to rest after years of extensive experience with lasers in IVF (In Vitro Fertilization) labs the world over. Lasers now allow us to safely perform cellular microsurgery in the IVF lab, and are routinely used for assisted hatching in many labs. Assisted hatching involves using the laser to create a precise opening in the shell ( zona) of the embryo prior to transferring it. Such an opening helps the embryo to hatch more easily, thus increasing the chances of it implanting successfully in the uterus.
After so many years of using the laser, doctors are now exploring new frontiers with it in the IVF lab - what else can we do with this remarkable tool to help infertile patients ?
We use the laser routinely in our lab for performing embryo biopsies for preimplantation genetic diagnosis ( PGD). The laser allows to create a well-defined opening through the zona, through which it is possible to safely and atraumatically remove a single blastomere from the embryo. You can see what a laser assisted embryo biopsy at www.drmalpani.com/pgd/laserbiopsy.htm.
Researchers have also used the laser for ICSI ( intracytoplasmic sperm injection). The trickiest part of ICSI is the technical difficulty involved in capturing a single motile sperm and crushing its tail in order to immobilize it prior to injecting it into the egg. Using a laser beam , this can be performed with much greater ease and speed, thus dramatically reducing the time taken to perform ICSI.
ICSI can be especially difficult to perform when there are very few eggs, or the eggs are fragile, because these are easily damaged when the injection pipette is introduced through the zona into the cytoplasm of the embryo. Laser assisted ICSI allows us to create a very small opening in the zona, through which the injection pipette carrying the sperm can be easily carried into the egg. This technique has been shown to reduce damage to fragile eggs during ICSI, and increase fertilization rates as well.
The laser also allows us to perform cellular microsurgery on the embryo. For example, a study has shown that it's possible to achieve a dramatic increase in pregnancies from frozen embryos with laser-assisted removal of dead cells. Researchers at the European Hospital in Rome have shown that removing necrotic cells from frozen thawed embryos greatly enhances a patient's chances of becoming pregnant. Based on other researchers' work with mouse embryos, the doctors hypothesized that removing dead blastomeres from embryos damaged in the freezing and thawing process would prevent their release of toxic metabolites that are harmful to the survival and development of healthy cells and the embryo as a whole and would result in higher pregnancy rates for their patients. A pilot study was organized in which 235 couples who had frozen embryos from prior IVF cycles were randomly assigned to two treatment groups. Both groups had transfers utilizing their undamaged and partially damaged embryos that survived thawing. Three surviving embryos were selected for each couple from a maximum of ten thawed. Laser-assisted hatching was used to drill a small hole in the embryos' outer membranes. Undamaged embryos were then cultured without further manipulation. In the control group, partially damaged embryos were also cultured without any more treatment. In the study group, embryos that had undergone some freeze/thaw damage were treated by removing any dead cells they contained. Embryos were transferred to the patients after 18 to 20 hours of culture, during which the researchers observed that 74.3% of the partially damaged embryos in the treated group divided, while only 27.5% of the partially damaged control embryos divided. Monitoring their patients' progress, they found that 40% of the study group established an ongoing pregnancy compared to 11.4% of patients in the control group. It was clear that the removal of necrotic blastomeres greatly improved patients' chances of becoming pregnant from a frozen/thawed cycle. The randomized study ended and the treatment was made standard in the hospital's Centre for Reproductive Medicine. The researchers followed up with an observational clinical series confirming the improvement in pregnancy rates: 34.5% from frozen/thawed cycles in which dead cells were removed from their embryos. Prior studies, not using this technique, have shown that rates of pregnancy and implantation with frozen-thawed embryos range from 10% to 30% and 5% to 15% respectively. "It's very exciting to see this new technique significantly increase patients' chances of becoming pregnant using their frozen-thawed embryos. For many of them, it will reduce the number of IVF attempts they have to go through and could also reduce their risks of having higher order multiple pregnancies by giving them the confidence to transfer fewer embryos," commented William Keye, Jr., MD, President of the American Society for Reproductive Medicine. (Rienzi, et al, Laser-assisted removal of necrotic blastomeres from cryopreserved embryos that were partially damaged, Fertility and Sterility, Vol.77, No.6, June 2002).
What of the future ? It may be possible to use the laser to actually perform "surgery" on chromosomes in the egg and embryo, thus allowing us to correct and repair genetic defects (for example , it may be possible to remove an extra 21 chromosome found in embryos with trisomy 21). Science fiction ? perhaps, but fiction has a way of soon becoming reality in the IVF (In Vitro Fertilization) lab !