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The latest news in Science: May 2021

The latest news in Science: May 2021

In this section we attempt to draw attention to science papers we perceive as potentially important for the basic understanding of reproductive biology and, therefore, may have translational relevance to infertility practice at some future point.

We already discussed in CHR’s recent publication list the study in Nature Cell Biology in collaboration with the Brivanlou laboratory at Rockefeller University which clearly was one of the most important basic science papers published in April[1]. We also addressed in this month’s ethics article in this issue of The VOICE the recently published paper by Tan et al in Cell,[2] which attracted so much critical attention because it involved creation of chimera between human and monkey cells. Both of these publications would, otherwise, have appeared in this listing.

Bioelectrical signaling between cells

We this month also recommend a review article in Cell[3] by Michael Levine, PhD, who is a Distinguished Professor and the Vannevar Bush Chair in the Biology Department at Tuft University’s Allen Discovery Center and was the first to characterize the molecular and genetic mechanisms that allow embryos to consistently form left-right asymmetric body structures in a universe that macroscopically does not make such a distinction. He in this paper describes in very interesting detail how individual cell behaviors are coordinated toward invariant-large -scale anatomical outcomes in development as well as regeneration despite unpredictable perturbations. He explains that in all tissues processed information is endogenously distributed through membrane potentials, produced by ion channels and gap junctions. These bioelectrical networks process morphogenetic information that controls gene expression which, in turn, allows cell collectives to direct large-scale growth and generation of final forms of tissues. Pointing toward the future, he predicts that such bioelectrical signaling can potentially be exploited to treat developmental disorders, further progress in regenerative medicine, allow for cancer reprogramming and enhance synthetic bioengineering efforts.

Glucocorticoids affect follicle competency in primates

In a fascinating paper from the Oregon Health & Science University School of Medicine, in Portland, OR (and its National Primate Research Center), investigators explored metabolomics of follicular fluid in 74 rhesus macaque and correlated the findings with oocyte quality from these follicles and their ability to lead to generation of blastocysts. Reported in Scientific Reports Open,4 in the process, the investigators identified 60 metabolites that significantly differed between embryo classifications. One, however stood out in defining oocytes that reached blastocyst-stage: a notable increase in intrafollicular ratio of cortisol to cortisone. In further defining the underlying physiology of this finding, they discovered evidence for an important role of the glucocorticoid receptor NR3C1 in regulation of the follicular processes via paracrine signaling. Knockdown of NR3C1 prevented expansion of cumulus granulosa cells.

Considering that glucocorticoids are widely used in association with IVF, these findings have potential clinical significance and demand further exploration in humans. Moreover, as the investigators in addition identified many additional metabolites that statistically associated with varying IVF outcomes, this study suggests that similar studies in human might help in oocyte selection during IVF. These data also reemphasized a point CHR investigators have repeatedly made in many publications and was expressed before on several occasions in the pages of this newsletter: To select embryos at cleavage or blastocyst-stage may be too far downstream to offer significant clinical benefits. Embryo selection may be more precise if based on more upstream oocyte quality. A paper from CHR investigators further proving this point is currently in press in Fertility & Sterility and should be appearing electronically in May.

Cytokine profile in the peri-implantation period: Further evidence that inflammation is bad for pregnancy success

Zhao et al from the Chinese University in Hong Kong, China, reported an interesting study on cytokine profiles of women around the implantation period. We found the study of interest for what it did not demonstrate:[5] 47 women who underwent IVF with selective single embryo transfer (eSET) at blastocyst-stage, surprisingly (at least for us here at CHR), demonstrated on day of eSET similar cytokine profiles, whether they conceived or not.

Considering implantation being an immune system-dependent process, one would expect that women with, for example, hyperactive immune systems (autoimmunity, inflammation, severe allergies) would demonstrate differences. Considering the study’s exclusion criteria such women, however, were likely mostly excluded. This study, moreover, also excluded poorer prognosis patients by mandating at least one transferrable blastocyst-stage embryo. As previously discussed in The VOICE, such selection biases are, unfortunately, frequently overlooked in peer review, even if, as in this study, authors do not even point out that their patient selection bias allows only for conclusions in good-prognosis patients. Exporting such findings to all IVF cycles is statistically inappropriate and, likely, always misleading. One, therefore, can as of this point only conclude that good-prognosis patients with negative medical histories, apparently, have an immune system that does not contribute to pregnancy success/failure in IVF with blastocyst-stage transfer.

The authors, however, then in addition claim that, among women who did conceive, they found a “modest” (i.e., clinically likely insignificant) increase in pro-inflammatory cytokines (IFN-gamma, IL-1) 3 days after embryo transfer (i.e., ca. 24 hours after implantation), followed 3 further days later (days after transfer) by a surge in anti-inflammatory cytokines (IL-10, TGF-ß1) which was maintained till day-9 when pregnancy tests were obtained).

Neither authors nor an accompanying editorial,6 however, recognized the real significance of these findings which defined what in normal patients happens: With implantation, the immune system turns “anti-inflammatory” because implantation is, of course, an “inflammatory” process that must be contained. In other words, this study confirms what we at CHR have been preaching for many years: Inflammation is “bad” for pregnancy success. We, therefore, check our patients routinely for inflammatory markers and aggressively pursue anti-inflammatory treatments when indicated.

Authors and commentators in their irrelevant concern about whether embryos had undergone PGT-A,[6] however, also completely missed that this study now also demands a follow-up study of abnormal patients with known medical problems, including evidence of a hyperactive immune system, which then should reveal the really interesting findings how cytokine profiles in so-affected women differ from normal good-prognosis patients.

More on Inositols and PCOS

We previously in these pages pointed out that hypo-androgenic infertile women should not be on myoinositol because it further lowers androgens [LINK]. Especially in PCOS patients myoinositol is widely, and in most cases appropriately, used because most PCOS patient, especially those with “classical” phenotype-A PCOS, will benefit from lower androgen levels.

Women with so-called hypo-androgenic PCOS-like phenotype (H-PCOS), the clinical presentation of the “lean” phenotype-D PCOS above age 35 years, will, however, not benefit from supplementation with myoinositol (or other inositols) because these patients already are hypo-androgenic. They, indeed, may be harmed because the inositol may counteract the testosterone-raising effects of DHEA supplementation, CHR usually recommends to women above age 40 and women with low functional ovarian reserve.

Now comes a timely review paper from mostly Italian colleagues addressing the interplay between PCOS and inositol in much detail[7]. Though the authors do not address H-PCOS, the paper is worth the read to better understand how the two principal inositols potentially affect ovaries in different ways.

Does DHEA exert a beneficial effect on the female heart?

A recent paper in the medical endocrinology literature caught our attention because it involved the hormone DHEA (and its sibling DHEA-S), and CHR, of course, has a special interest in this hormone since we feel responsible for its worldwide use in female infertility. Two Australian investigators in this manuscript discuss effects of androgens on the heart in males and females[8]. Not surprisingly there are quite significant differences: They note that conversion of adrenal androgens to testosterone contributes to males only a minor degree of total peripheral androgens; in women the contribution is, however, substantial. CHR investigators have written about the importance of adrenal androgen production in women for years, most recently in a paper just published and discussed elsewhere in this newsletter[9].

Adrenal androgen production is defined by DHEA-S, the only androgen hormone almost exclusively only produced in adrenal glands. The authors, therefore, point out that the reported association of lower DHEA-S with higher incidence of heart failure and heart failure with reduced ejection fraction in postmenopausal women suggests (but does not prove) a possible benefit of androgens on the female heart. Interestingly, SHBG did not demonstrate any association. As we at CHR probably know better than anybody else, low DHEA-S is a very frequent finding in infertile women even before menopause, especially, however, in women with H-PCOS. Clearly something to have an eye out for!

More bad news for preimplantation genetic testing for aneuploidy (PGT-A)

We elsewhere in this newsletter already presented recent studies and opinions offering more evidence for the clinical futility of PGT-A and reasons why the procedure, simply for biological reasons, cannot achieve its promised goals of improving IVF outcomes. Now come investigators from various U.S. IVF centers, including the Eunice Kennedy Shriver National Institute of Child health and Human Development, Reproductive Endocrinology and Infertility fellowship at the National Institutes of Health, Bethesda, MA, reporting on outcomes in donor oocyte recipient cycles who underwent PGT-A[10] Not surprisingly, the procedure did not improve IVF outcomes in donor-recipient cycles.

This is, of course, not the first study to reach this conclusion; the study is, however worth a short shout-out nevertheless because utilization of PGT-A in donor-recipient cycles, where egg donors usually are in their 20s and where pregnancy rates are the highest of all IVF cycle categories, even believing in the utility of PGT-A with IVF, simply never made sense. CHR always perceived the routine utilization of PGT-A in donor recipient cycles as the ultimate abusive utilization of PGT-A.

PGT-A was also again a major subject in the annual “Best of ASRM & ESHRE Meeting” (this year only virtual). Following a standard format of a pro- vs. a con-speaker, in reality, two pro-speakers, however, debated each other: Richard Paulson, MD, from Los Angeles, U.S., as the alleged con-voice, is actually a proponent of PGT-A who believes that, once PGT-A can be performed in non-invasive fashion, it will finally show its clinical effectiveness. He also believes that the confusion regarding mosaic embryos can be resolved by simply no-longer calling them “mosaic”[10] As noted elsewhere in this newsletter in discussion of our last month published paper in Nature Cellular Biology,[1] neither of these two arguments makes sense. How removed from biological realities Paulson’s opinions really are is well demonstrated by him recommending in the debate egg donation cycles as one of the indications for PGT-A.

Prof Luca Gianaroli, MD from Italy was selected as the con-speaker because, together with Yuri Verlinsky, PhD, from Chicago, IL, the two must be viewed as the fathers of what now is called PGT-A. Both were also founding members of the Preimplantation Genetic Diagnosis International Society (PGDIS), the organization primarily responsible for how PGT-A is clinically utilized, performed, and reported.

Even the question, addressed by the alleged debate of opposing opinions was already rather absurd: PGT-A for all?, - as if there is any medical treatment that ever should be performed for everybody? The poll taken after the debate was 85% of participants were in favor of selective use of PGT-A and 15% argued in favor of universal use. One wonders who those 15% are; but we, here at CHR, wonder even more when ASRM and/or ESHRE, finally, include the options of not using PGT-A at all into one of their debates? We assume that this will only happen once their budgets are no longer dependent on the support of the genetic testing industry.

Further reinforcement that “fresh” is better than “frozen”

Our final subject addresses again a contested position CHR has maintained for years against an onslaught of poorly designed and highly biased studies, - what gives us better pregnancy chances in IVF fresh or frozen-thawed cycles? The question is, of course, best answered in donor-recipient cycles because co-variables in young egg donors are relatively minimal. CHR previously reported, based on national data, that fresh donor recipient cycles produced significantly higher pregnancy and live birth rates than frozen donor egg cycles[11]. Some colleagues claimed that initial differences were only due to inexperience with egg-freezing in early days of frozen donor egg banks;[12] but CHR investigators then demonstrated that the difference with time had even expanded to over 10% in absolute pregnancy chances[13].

Now colleagues from the University of Colorado looked at the same question even a few years later with even larger national numbers and reported that a “good obstetrical outcome” was 27% more likely with fresh compared to frozen embryo transfer. Moreover, live births were 55.7% vs. 39.5%, a 16.2% absolute difference[14]. In other words, differences between fresh and frozen oocytes have even further grown. Fresh is clearly better than frozen!


  1. Yang M, Rito T, Metzger J, Naftaly J, Soman R, Hu J, Albertini DF, Barad DH, Brivanlou AH, Gleicher N. Depletion of aneuploid cells in human embryos and gastruloids. Nat Cell Biol 2021;23:314-321
  2. Tan et al., Chimeric contribution of human extended pluripotent stem cells to monkey embryos ex vivo. Cell 2021;184(8):2020-2032
  3. Levine M Bioelectrical signaling: Reprogrammable circuits underlying embryogenesis, regeneration, and cancer. Cell 2021;184(8):1971-1989
  4. Ravisankar S et al., Metabolomics analysis of follicular fluid coupled wit oocyte aspiration reveals importance of glucocorticoids in primate periovulatory follicle competence. Sci Rep Open 2021;11:6506
  5. Zhao et al. Successful implantation is associated with a transient increase in serum pro-inflammtory ctokine profile followed by a switch to ant-inflammatory cytokine profile prior to confirmation of pregnancy. Fertil Steril 2021;115(4)1044-1052
  6. De los Santos MJ, Alecsandru D. Circulating cytokines during the blastocyst peri-implantation period. Fertil Steril 2021;115(4):905-906
  7. Monastra et al., PCOS an inositols: Controversial results and necessary clarifications, basic differences between D-chiro and myo-inositol. Front Endocrinol 2021;12:660381
  8. Yeap BB, Dwivedi G. Androgens and heart failure: New observations illuminating and aging conundruma. J Clin Endocrinol Metab 2021;106(3):e1476-e1478
  9. Gleicher N, Darmon S, Molinari E, Zhang L, Hu J, Albertini DF, Barad DH. A form of secondary ovarian insufficiency (SOI) due to adrenal hypoandrogenism as a new fertility diagnosis. Endocrine 2021;72:260-267
  10. Paulson RJ, Treff NR. Isn’t it time to stop calling preimplantation embryos “mosaic”? Fertil Steril Rep 2020;1(3):164-165
  11. Kushnir VA. .... Gleicher N. Outcomes of fresh and cryopreserved oocyte donations. JAMA 314(6):623-624
  12. Grifo JA et al., Fresg vs cryopreserved donor oocytes. JAMA 2015;314(23):2569-2570
  13. Kushnir VA . .... Gleicher N. New national outcome data on fresh versus cryopreserved donor oocytes. J Ovarian Res 2018;11(1):2
  14. Roeca C, et al.. Birth outcomes are superior after transfer of fresh versus frozen embryos for donor oocyte recipients. Hum reprod 2020;35(12):2850-2859

Norbert Gleicher, MD

Norbert Gleicher, MD, FACOG, FACS

Norbert Gleicher, MD, leads CHR’s clinical and research efforts as Medical Director and Chief Scientist. A world-renowned specialist in reproductive endocrinology, Dr. Gleicher has published hundreds of peer-reviewed papers and lectured globally while keeping an active clinical career focused on ovarian aging, immunological issues and other difficult cases of infertility.

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