The results obtained by Prof. Antonin Bukovsky and coworkers are exciting but, as was mentioned by Prof. Tilly from Harvard Medical School,one has not succeeded as of yet to fertilize eggs that have been generated in vitro. My question therefore is: why can't this estrogenic stimulus be given locally, directly to the ovaries? When given peripherally, the amount of estrogen needed might be very elevated and, I assume, might enhance the risks of cancer. The natural gradient of estrogen would be from the ovaries out to the periphery, and not the way fertility drugs are usually administered. Can anyone enlighten me as of why this could not be done and this way avoid the problem of the in vitro development of the oocytes?
Competing interests
None declared
The article is not well documented
Pavel Travnik, REPROMEDA Center of Assisted Reproduction
16 May 2005
In my opinion the article shows absolutely no evidence of the oocyte development in the culture of ovarian surface epithelium. The quality of the microphotographs is mostly poor but it allows to refuse the assertion that the cells demonstrated are „of oocyte phenotype“. The statement „ZP+ intermediated filaments“ is not acceptable. The concept of intermediate filamentous form of ZP proteins in the cytoplasm may originate of the confusion of slides (cytokeratin has the form of intermediate filaments) etc. etc.
Competing interests
None declared
RE: Oogenesis by direct stimulation of ovaries
Antonin Bukovsky, The University of Tennessee Graduate School of Medicine
20 May 2005
The suggestion to give estrogenic stimulus locally, directly to the ovaries, is interesting, but one has to consider that conditions in vivo are distinct from those in vitro. The concentration of estrogen utilized in vitro was relevant to the systemic estrogen levels during preovulatory period. The preovulatory levels of estradiol continue to be produced by cycling ovaries of women after 40 years of age, which show no follicular renewal resulting in gradual depletion of persisting primary follicles.
Competing interests
None declared
RE: The article is not well documented
Antonin Bukovsky, The University of Tennessee Graduate School of Medicine
20 May 2005
The manuscript passed two rounds of peer review, which was managed by Deputy Editor. The observation of ZP expression in intermediate filaments of some oocyte phenotype cells is correct, since the less developed cell shown in Fig. 3a was immunostained in the same culture chamber as a more developed cell shown in Fig. 3e with surface ZP expression and no staining of intermediate filaments. Hence, there was no confusion of "slides." The studies of human eggs in vitro usually utilize mature eggs collected for IVF purposes, which exhibit surface ZP staining. Our observations indicate that during oocyte development, the ZP glycoproteins can temporarily be expressed in the intermediate filaments.
Oogenesis by direct stimulation of ovaries
11 May 2005
The results obtained by Prof. Antonin Bukovsky and coworkers are exciting but, as was mentioned by Prof. Tilly from Harvard Medical School,one has not succeeded as of yet to fertilize eggs that have been generated in vitro. My question therefore is: why can't this estrogenic stimulus be given locally, directly to the ovaries? When given peripherally, the amount of estrogen needed might be very elevated and, I assume, might enhance the risks of cancer. The natural gradient of estrogen would be from the ovaries out to the periphery, and not the way fertility drugs are usually administered. Can anyone enlighten me as of why this could not be done and this way avoid the problem of the in vitro development of the oocytes?
Competing interests
None declared
The article is not well documented
16 May 2005
In my opinion the article shows absolutely no evidence of the oocyte development in the culture of ovarian surface epithelium. The quality of the microphotographs is mostly poor but it allows to refuse the assertion that the cells demonstrated are „of oocyte phenotype“. The statement „ZP+ intermediated filaments“ is not acceptable. The concept of intermediate filamentous form of ZP proteins in the cytoplasm may originate of the confusion of slides (cytokeratin has the form of intermediate filaments) etc. etc.
Competing interests
None declared
RE: Oogenesis by direct stimulation of ovaries
20 May 2005
The suggestion to give estrogenic stimulus locally, directly to the ovaries, is interesting, but one has to consider that conditions in vivo are distinct from those in vitro. The concentration of estrogen utilized in vitro was relevant to the systemic estrogen levels during preovulatory period. The preovulatory levels of estradiol continue to be produced by cycling ovaries of women after 40 years of age, which show no follicular renewal resulting in gradual depletion of persisting primary follicles.
Competing interests
None declared
RE: The article is not well documented
20 May 2005
The manuscript passed two rounds of peer review, which was managed by Deputy Editor. The observation of ZP expression in intermediate filaments of some oocyte phenotype cells is correct, since the less developed cell shown in Fig. 3a was immunostained in the same culture chamber as a more developed cell shown in Fig. 3e with surface ZP expression and no staining of intermediate filaments. Hence, there was no confusion of "slides." The studies of human eggs in vitro usually utilize mature eggs collected for IVF purposes, which exhibit surface ZP staining. Our observations indicate that during oocyte development, the ZP glycoproteins can temporarily be expressed in the intermediate filaments.
Competing interests
None declared