Customer Success Stories
Oosight: SCNT
Issue: Find a non-invasive replacement to the "Hoechst plus UV illumination" method to more safely identify the location of the nucleus during enucleation of oocytes.
Solution: Employ the use of Oosight to effectively and efficiently identify the position of the spindle apparatus thereby increasing yields.
A team of researchers at Oregon National Primate Research Center of OHSU, led by Dr. Shoukhrat Mitalipov, have been at the forefront of their field in performing and developing procedures related to somatic cell nuclear transfer for the advancement of stem cell research. Previous attempts to develop stem cells from cloned monkey embryos were unsuccessful, leading Dr. Mitalipov to seek alternate methods to improve the SCNT process.
Dr. Mitalipov believed that the traditional method of using Hoechst staining + UV illumination to visualize the genetic material during enucleation was part of the issue in potentially damaging the egg thereby resulting in low yields, so he turned to CRi and the Oosight system. The system allowed Mitalipov to overcome the invasive issues related to traditional methods. It also enabled them to visualize the genetic material throughout the process of enucleation in order to ensure complete removal of the nuclear complex, and also to minimize the extraction of vital cytoplasmic DNA. The scientists found that the use of the system resulted in a much improved survival rate for developing clones.
Click on image to enlarge
Figure: enucleated rhesus monkey, imaged with Oosight. Arrowhead indicates the spindle. Note that the entire spindle apparatus has been removed, ensuring that the host oocyte is capable of accepting the somatic cell. (also include link to time-lapse movie of enucleation)
In November of 2007 Mitalipov's team made international headlines following the publication in the November edition of the scientific journal Nature, citing the production of dozens of cloned embryos from a 10-year-old macaque. Dr. Mitalipov's team was then able to extract stem cells from some of the cloned monkey embryos, persuading them to develop into mature heart and nerve cells in the laboratory.
Reference:
- Byrne JA, Pedersen DA, Clepper LL, Nelson M, Sanger WG, Gokhale S, Wolf DP, Mitalipov SM. Nature. 2007 Nov 22;450(7169):497-502. Epub 2007 Nov 14.
Oosight: In Vitro Fertilization
Issue: How to improve the likelihood of pregnancy in frozen egg cycles.
Solution: The Oosight™ imaging system enables the visualization and measurement of the meiotic spindle post-thaw to help detect cryodamage, thereby improving results through better selection.
The NYU Fertility Center in New York City is one of the largest and well-known clinics worldwide. The program began offering an egg freezing program a few years ago to help combat infertility associated with sterilization through medical treatment and also due to the growing population of woman who are delaying childbearing until later in life.
In the past few years, the clinical application of egg freezing in the field of assisted reproductive technologies (ART) has advanced considerably as protocols are refined and egg-specific cryoprotectants are made available. Despite this progress, egg freezing success rates remain low and egg viability continues to be compromised primarily because the ultrastructure of eggs remains highly susceptible to cryodamage. The IVF group at NYU turned to the Oosight system as a tool to assess viability in order to ensure that these ultrastructures are in fact healthy and structurally sound. By being able to identify spindle presence using the system, the group at NYU employed an assay that selected for those that were spindle positive following thawing (Fig 1). NYU boasts some of the best success with egg freezing, attributing some of that success to this screening method.
Figure 1. Human MII oocyte with a strongly birefringent, barrel-shaped spindle (A), and one without (B).
Dr. Nicole Noyes, Associate Professor and the Director of Reproductive Surgery and Quality Assurance in the Department of Obstetrics and Gynecology at NYU, adds that "because spindle screening can improve efficiency of gamete selection, it should be considered when choosing eggs for freezing or fertilization by ICSI. Improved selection should bring us closer to the universal goal of a single embryo transfer. As egg freezing success progresses, we should move away from creating and freezing "extra" embryos in favor of extra eggs" (Noyes 2007).
Reference:
- Noyes N, Chang HC, Labella P, McCaffrey C, Fino E, Grifo JA. Fert Steril. 2007 Sep;88(Suppl 1):S335.
