Hum. Reprod. Advance Access originally published online on March 30, 2007
Human Reproduction 2007 22(6):1795-1796; doi:10.1093/humrep/dem047
Letters to the Editor |
Cryopreservation of intact human ovary with its vascular pedicle—or cryopreservation of hemiovaries?
Department of Gynecology, Université Catholique de Louvain, Brussels, Belgium
1 Correspondence address. Department of Gynecology, Université Catholique de Louvain, Brussels, Belgium. E-mail: donnez{at}gyne.ucl.ac.be
We read with interest the manuscript of Bedaiwy et al. (2006)
entitled ‘Cryopreservation of intact human ovary with its vascular pedicle’, but feel there are some important details that the authors need to address for a clearer understanding of their work.
First, we do not agree with the title, which suggests that ‘intact human ovary has been cryopreserved with its vascular pedicle’. Indeed, in both the title and the manuscript, the authors defined the ovaries as intact ovaries for all the steps of the cryopreservation protocol. However, after perfusion with cryoprotective agent prior to freezing, the ovaries were bisected and therefore, from this moment on, they should be called hemiovaries. Hence, the first aim of their study was not achieved as they described a protocol that allows preservation of a hemiovary, not a whole ovary, and so the title should be ‘Cryopreservation of human hemiovaries’. The present title causes confusion and falsely implies that the ovary was cryopreserved with its vascular pedicle with a view to future transplantation by vascular anastomosis, which is simply not true! Moreover, in each case, one ovary was cryopreserved in the form of cortical strips and not as a whole ovary. We would also like to have more information on the methodology used to bisect the ovary, mainly regarding the vascular pedicle, as the ovary only has one ovarian artery.
Second, we would like to know the size of the two intact human ovaries that were used in the study. Indeed, even though they came from older patients (44 and 46 years of age), and were cut into two parts, it seems hardly likely that they could fit into cryovials of 1.27 cm diameter. It also means that if this protocol were used for younger patients, whose ovaries have a mean size of 2.5–3 x 2 x 2 cm (Motta and Balboni, 1994), the ovaries would have to be cut into more than two pieces. The cryovial used in Bedaiwy's study had a volume capacity of 5 ml but, according to Kupesic et al. (2003), the mean human ovarian volume is 10 ml in women < 30 years of age, 8.30 ml from 31 to 35 years and 6.85 ml from 36 to 40 years. Therefore, regardless of the age of patients, an intact human ovary could never fit into a 5-ml cryovial. Thus, cryopreservation of intact human ovaries cannot be performed with a standard programmable Planer freezer, as used by Bedaiwy et al. (2004, 2006), because cryovials with a diameter greater than 1.27 cm do not fit into its cryochamber.
Third, we do not understand why Bedaiwy used fetal calf serum (FCS) in the freezing and thawing medium as, for transplantation purposes, animal-free media must be used to avoid the risk of contamination.
Fourth, as mentioned by the authors, their work was presented at the ESHRE annual meeting in Berlin, 2004 (Bedaiwy et al., 2004). We, however, note discrepancies in the described protocols between the paper submitted to ESHRE and the present paper, although they apparently concern the same patients aged 44 and 46 y. Indeed, in the 44-year-old patient, one ovary was cryopreserved as an intact ovary without bisection and the other as cortical pieces, whereas in the 46-year-old, both ovaries were frozen in the form of cortical strips (Bedaiwy et al., 2004).
Fifth, the authors described a thawing protocol where the ovaries were perfused in order to remove the cryoprotectant, but how could adequate perfusion be performed if the vascular network, as well as the rest of the ovary, were cut into two parts? Indeed, areas of the hemiovary previously served by a vessel that has been bisected cannot be perfused, and thus the cryoprotectant cannot be removed by perfusion. In these areas, the only way of removing the cryoprotectant would be by diffusion from the deepest parts to the surface. However, 20 min seems insufficient to achieve complete diffusion through a thick tissue fragment like a hemiovary. Moreover, the composition of the thawing medium differed between the ESHRE abstract and the present paper.
Sixth, in the discussion, the authors compared their results on follicular viability (using 1.5 M DMSO) with those of Martinez-Madrid et al. (2004) (using 10% DMSO), stating that ‘this could probably mean that ovarian tissue could tolerate adequately varying concentrations of DMSO with comparable post-thaw survival’, as follicular viability in both studies was similar. We do not understand what they mean by varying concentrations, as 1.5 M DMSO is almost the same as 10% DMSO (1.4 M).
In effect, Bedaiwy's study described a protocol for cryopreservation of hemiovaries and, moreover, in older patients. The clinical interest of this study is questionable since vascular anastomosis cannot be performed with a hemiovary, and thus the goal of avoiding ischemic damage after transplantation cannot be achieved. We were very surprised that these comments were not made before publication.
We would finally like to point out that cryopreservation of a whole ovary, using the vascular pedicle for perfusion of cryoprotectant and with a view to transplantation by vascular anastomosis, has been successfully carried out in nine patients in our group so far according to our previously described protocol (Martinez-Madrid et al., 2004; Donnez et al., 2006).
References
Bedaiwy MA, Falcone T, Biscotti C, et al. (2004) Cryopreservation of intact human ovary with its vascular pedicle. Hum Reprod 19:i77 (O-220).
Bedaiwy MA, Hussein MR, Biscotti C, Falcone T. (2006) Cryopreservation of intact human ovary with its vascular pedicle. Hum Reprod 21:3258–9.
Donnez J, Martinez-Madrid B, Jadou Pl, et al. (2006) Ovarian tissue cryopreservation and transplantation: a review. Hum Reprod Update 12:519–35.
Kupesic S, Kurjak A, Bjelos D, et al. (2003) Three-dimensional ultrasonographic ovarian measurements and in vitro fertilization outcome are related to age. Fertil Steril 79:190–7.[CrossRef][Web of Science][Medline]
Martinez-Madrid B, Dolmans MM, Van Langendonckt A, et al. (2004) Freeze-thawing intact human ovary with its vascular pedicle with a passive cooling device. Fertil Steril 82:1390–94.[CrossRef][Web of Science][Medline]
Motta PM and Balboni GC. (1994) Apparato genitale femminile. In Ermes (Ed.). Anatomia Umana 3rd edn (Milano, Italy) Ed. Ermes.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  I. Demeestere, P. Simon, S. Emiliani, A. Delbaere, and Y. Englert Orthotopic and heterotopic ovarian tissue transplantation Hum. Reprod. Update, November 1, 2009; 15(6): 649 - 665. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||