title: Polar body transfer restores the developmental potential of oocytes to blastocyst stage in a case of repeated embryo fragmentation.
abstract: OBJECTIVE
  We aimed to determine the developmental potential of human reconstructed oocytes after polar body genome transfer (PBT) and to report the case of a woman with multiple cycles of severe embryo fragmentation.
  
  
  METHODS
  Fresh and cryopreserved first polar bodies (PB1s) were transferred to enucleated metaphase II oocytes (PB1T), while fresh PB2s were removed from fertilized oocytes and used instead of the female pronucleus in donor zygotes. Reconstructed oocytes underwent intracytoplasmic sperm injection (ICSI) and were cultured to blastocyst. Biopsied trophectoderm cells of PBT-derived blastocysts were screened for chromosomes by next-generation sequencing (NGS). Then, cryopreserved PB1T was carried out in one woman with a history of several cycles of extensive embryo fragmentation, and the blastocysts derived from PB1T were screened for aneuploidy but not transferred to the patient.
  
  
  RESULTS
  There were no significant differences in the rates of normal fertilization and blastocyst formation between fresh and cryopreserved PB1T and control oocytes. Of the three fresh and three cryopreserved PB1T-derived blastocysts, two and one blastocysts exhibited normal diploidy respectively. In contrast, 17 PB2 transfers yielded 16 two pronuclei (2PN) zygotes with one normal and one small-sized pronucleus each and no blastocyst formation. In the female patient, 18 oocytes were inseminated by ICSI in the fourth cycle and the PB1s were biopsied. Although the embryos developed from the patient's own oocytes showed severe fragmentation, the oocytes reconstructed after PB1T produced three chromosomally normal blastocysts.
  
  
  CONCLUSIONS
  Normal blastocysts can develop from human reconstructed oocytes after PB1T. The application of the first PB transfers may be beneficial to patients with a history of poor embryo development and excessive fragmentation.
authors.affiliation: Institute of Reproductive and Stem Cell Engineering, Central South University, Xiangya Road 88#, 410078, Changsha, People's Republic of China.|Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.
authors.forename: Shuo-Ping
authors.initials: SP
authors.lastname: Zhang
authors.affiliation: Institute of Reproductive and Stem Cell Engineering, Central South University, Xiangya Road 88#, 410078, Changsha, People's Republic of China.|Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.|Key laboratory of Reproductive and Stem Cell Engineering, Ministry of Health, Changsha, China.
authors.forename: Chang-Fu
authors.initials: CF
authors.lastname: Lu
authors.affiliation: Institute of Reproductive and Stem Cell Engineering, Central South University, Xiangya Road 88#, 410078, Changsha, People's Republic of China.|Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.|Key laboratory of Reproductive and Stem Cell Engineering, Ministry of Health, Changsha, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Gong
authors.affiliation: Institute of Reproductive and Stem Cell Engineering, Central South University, Xiangya Road 88#, 410078, Changsha, People's Republic of China.|National Engineering and Research Center of Human Stem Cell, Changsha, China.
authors.forename: Ping-Yuan
authors.initials: PY
authors.lastname: Xie
authors.affiliation: Institute of Reproductive and Stem Cell Engineering, Central South University, Xiangya Road 88#, 410078, Changsha, People's Republic of China.|Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.|Key laboratory of Reproductive and Stem Cell Engineering, Ministry of Health, Changsha, China.|National Engineering and Research Center of Human Stem Cell, Changsha, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Hu
authors.affiliation: Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.
authors.forename: Shun-Ji
authors.initials: SJ
authors.lastname: Zhang
authors.affiliation: Institute of Reproductive and Stem Cell Engineering, Central South University, Xiangya Road 88#, 410078, Changsha, People's Republic of China.|Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China.|Key laboratory of Reproductive and Stem Cell Engineering, Ministry of Health, Changsha, China.|National Engineering and Research Center of Human Stem Cell, Changsha, China.
authors.forename: Guang-Xiu
authors.initials: GX
authors.lastname: Lu
authors.affiliation: Institute of Reproductive and Stem Cell Engineering, Central South University, Xiangya Road 88#, 410078, Changsha, People's Republic of China. linggf@hotmail.com.|Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China. linggf@hotmail.com.|Key laboratory of Reproductive and Stem Cell Engineering, Ministry of Health, Changsha, China. linggf@hotmail.com.|National Engineering and Research Center of Human Stem Cell, Changsha, China. linggf@hotmail.com.
authors.forename: Ge
authors.initials: G
authors.lastname: Lin
mesh_terms: D000328:Adult; D001755:Blastocyst / Q000378:metabolism / Q000473:pathology; D015925:Cryopreservation; D004624:Embryo Transfer; D004622:Embryo, Mammalian / Q000503:physiopathology*; D047108:Embryonic Development / Q000235:genetics*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D008677:Metaphase; D009865:Oocytes / Q000254:growth & development* / Q000473:pathology; D059705:Polar Bodies / Q000473:pathology / Q000637:transplantation*; D020554:Sperm Injections, Intracytoplasmic
keywords: Assisted reproductive technique; Blastocyst; Embryo fragmentation; Polar body transfer