Cryopreservation of intact ovaries—size is a variable?
2005; Elsevier BV; Volume: 83; Issue: 5 Linguagem: Inglês
10.1016/j.fertnstert.2005.02.005
ISSN1556-5653
AutoresTommaso Falcone, Mohamed A. Bedaiwy,
Tópico(s)Ovarian function and disorders
ResumoWe read with interest the recent report by Revel et al. (1Revel A. Elami A. Bor A. Yavin S. Natan Y. Arav A. Whole sheep ovary cryopreservation and transplantation.Fertil Steril. 2004; 82: 1714-1715Abstract Full Text Full Text PDF PubMed Scopus (63) Google Scholar), and we have some observations. First, they claimed that their report is the first of its kind, which is not accurate. We reported the cryopreservation and autotransplantation of intact sheep ovary in an article published in Fertility and Sterility several years ago (2Bedaiwy M.A. Jeremias E. Gurunluoglu R. Hussein M. Biscotti C. Siemionow M. Restoration of ovarian function after autotransplantation of intact frozen-thawed sheep ovaries with microvascular anastomosis.Fertil Steril. 2003; 79: 594-602Abstract Full Text Full Text PDF PubMed Scopus (124) Google Scholar). Second, there is a high failure rate of the procedure (5 of 8 sheep) used in their experiment. This can be due to surgical technique, because they were unable to successfully perform the microvascular anastomosis in one third of the sheep. This might be because of the end-to-end vascular anastomosis technique reported. We have shown in the sheep model that an end-to-side vascular anastomosis has better results if there is vessel size discrepancy (2Bedaiwy M.A. Jeremias E. Gurunluoglu R. Hussein M. Biscotti C. Siemionow M. Restoration of ovarian function after autotransplantation of intact frozen-thawed sheep ovaries with microvascular anastomosis.Fertil Steril. 2003; 79: 594-602Abstract Full Text Full Text PDF PubMed Scopus (124) Google Scholar, 3Jeremias E. Bedaiwy M.A. Gurunluoglu R. Biscotti C.V. Siemionow Falcone T. Heterotopic autotransplantation and vascular anastomosis: a novel surgical technique.Fert Steril. 2002; 77: 1278-1282Abstract Full Text Full Text PDF PubMed Scopus (74) Google Scholar), and we were able to achieve 100% immediate patency in the grafts. Although vascular endothelial damage does occur from cryopreservation, we did not find it responsible for an unsuccessful vascular anastomosis. However, it might explain a postoperative thrombosis of a successfully anastomosed vessel. The recent literature has highlighted the importance of preservation of fertility in the cancer patient (4Falcone T. Attaran M. Bedaiwy M.A. Goldberg J.M. Ovarian function preservation in the cancer patient.Fertil Steril. 2004; 81: 243-257Abstract Full Text Full Text PDF PubMed Scopus (114) Google Scholar). Cryopreservation of ovarian tissue is one experimental approach. Different methods have been proposed for transplanting the tissue back into the patient. Most clinically used methods have focused on transplanting small ovarian tissue fragments in different clinically accessible anatomic sites. Ischemic necrosis of the tissue after transplantation results in loss of a large fraction of follicles. This might limit the long-term use of small ovarian tissue fragments. For this reason, we suggested that whole organ cryopreservation and transplantation might be an option (2Bedaiwy M.A. Jeremias E. Gurunluoglu R. Hussein M. Biscotti C. Siemionow M. Restoration of ovarian function after autotransplantation of intact frozen-thawed sheep ovaries with microvascular anastomosis.Fertil Steril. 2003; 79: 594-602Abstract Full Text Full Text PDF PubMed Scopus (124) Google Scholar). In this first report of successful cryopreservation and transplantation of an intact ovary in a large animal, we defined several areas that might limit this approach. These include the cryopreservation protocol, the surgical technique for vascular anastomosis, and the vascular endothelial tissue response to cryopreservation. A novel cryopreservation protocol that is designed for whole organ cryopreservation has the potential to improve the success rate of this technique. This is an extremely complex undertaking because of the lack of basic knowledge of the physical chemistry of an entire organ. Successful cryopreservation of an intact large-sized ovary is challenging owing to heat and mass transfer limitations, ischemia reperfusion injury, and intravascular ice formation problems. The report by Revel et al. has not addressed these issues. Furthermore, the results of this novel cryopreservation device do not seem to be successful when only 3 of 8 transplanted sheep resumed hormonal cyclicity. Can the authors suggest how this can be improved? The lack of data on follicular viability, histology, apoptotic signals, or any other data in the transplanted tissue limits the interpretation of this report. Was there any attempt, successful or otherwise, at achieving a pregnancy in these or previous experiments? Cryopreservation of intact ovaries—size is a variable? Reply of the AuthorsFertility and SterilityVol. 83Issue 5PreviewWe would like to thank Drs. Falcone and Bedaiwy for their thoughtful comments on our article (1). In what was defined as long-term patency in Bedaiwy's publication (2), only 3 of 11 grafts were still viable 8–10 days after autotransplantation. We performed the autotransplantation into the pedicle of the contralateral ovary, hoping to achieve natural pregnancy. There was no discrepancy in the vessel size, but because of the depth of these sites, this is far more challenging technically than transplantation to the superficial abdominal wall. Full-Text PDF
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