Parthenogenesis in human oocytes that were collected from resected ovarian tissue and matured in vitro

Currently, a major hurdle in the progress of human embryonic stem (hES) cell research is the lack of human oocytes with which to perform experiments. The collection process is a logistical and ethical challenge and usually involves the use of excess oocytes donated after assisted reproduction procedures. We collected resected human ovarian tissue after routine surgical procedures. Oocytes were isolated from the tissue and matured in vitro to the meiosis II (MII) stage, when the first polar body is extruded. With the large antral and smaller preantral follicles, the efficiencies of the maturation were nearly 50% and 25%, respectively. The quality of the matured oocytes was assessed by inducing parthenogenesis and >50% of the in vitro matured oocytes were competent enough to develop pronuclei and 33% developed at least to the two-cell stage 48 h after activation. Parthenotes continued to develop by 72 h but with significant blastomere fragmentation. These results provide evidence that resected ovarian tissue, which is normally discarded, may be a suitable alternative source for oocytes in hES cell research.