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Rescue in vitro maturation (IVM) is currently not a routine procedure in association with in vitro fertilization (IVF). We compared in a prospectively cohort study of 10 patients with normal functional ovarian reserve (NFOR) and of 25 with low functional ovarian reserve (LFOR), defined by abnormally high FSH and/or abnormally low AMH levels), IVM dynamics of immature oocytes. Following controlled ovarian hyperstimulation in IVF cycles, only immature oocytes underwent rescue IVM (for up to 48 h). Oocyte maturation dynamics, fertilization rates, embryo development, and pregnancy rates were then compared between NFOR and LFOR patients. Though proportion of MI and GV oocytes reaching MII stages within 48 h and rate of maturation of MI oocytes did not differ, in women with LFOR significantly more GV oocytes reached MII stage within 24 h (30.4 vs. 66.9 %; P= 0.013), while fertilization rates and embryo generation numbers were similar between both groups. Rescue IVM, thus, produced 1.5 additional embryos for transfer in women with LFOR and 1.6 in patients with NFOR, a highly significant difference in relative improvement in available embryo numbers for LFOR (+60.0 %) and NFOR women (+16.5 %). Rescue IVM, thus, not only demonstrates different time dynamics between women with LFOR and NFOR but also disproportionate efficacy in improving available embryo numbers for transfer in favor of LFOR patients. 1/7 patients, who reached embryo transfer with only embryos produced via rescue IVF conceived and delivered, proving that rescue IVF in women with LFOR also improves pregnancy and delivery chances. Because of the small number of embryos LFOR patients produce, every additional embryo is of considerable potential clinical significance for them, suggesting that rescue IVM in women with LFOR should become routine practice.

Testosterone activity, via the androgen receptor, on granulosa cells is increasingly recognized as essential for the early stages of folliculogenesisDehydroepiandrosterone (DHEA) supplementation of women with low functional ovarian reserve (LFOR) is a popular treatment for infertility, as these women almost universally have lower levels of testosterone than healthy womenDHEA supplementation has remained controversial primarily due to a lack of adequately powered clinical trials demonstrating its efficacy, but also owing to considerable variability in the metabolism of DHEA to testosteroneApproximately 10–15% of women who respond poorly to DHEA supplementation have insufficiently increased levels of testosterone—a major product of DHEA metabolismAbnormally poor metabolism of DHEA to testosterone can be caused by a number of known genetic variants, as well as by endocrine and immune conditionsHormonal responses to DHEA supplementation in women with LFOR can indicate genetic variants associated with poor metabolism of DHEA to testosterone and, thereby, suggest new personalized treatment options for these patients

ABSTRACTThe integrity of mitosis is dependent upon strict regulation of microtubule stability and dynamics. Although much information has been accumulated on regulators of the microtubule cytoskeleton, our knowledge of the specific pathways involved is still limited. Here we designed genetic screens to identify regulators of microtubule stability that are dispensable in the wild type yet become essential under microtubule-disrupting conditions. We found that the transcriptional cofactor Swi6p and activator Swi4p, as well as the G2/M-specific cyclin Clb2p, are required in a microtubule-destabilizing environment. Swi6p and Swi4p can combine as a transcriptional complex, called the SBF complex (SBF for Swi4/6 cell cycle box [SCB]-binding factor) that is functionally homologous to the metazoan DP1/2-E2F complex and that controls the G1/S transition through the genes it regulates. We show that Swi6p's contribution to microtubule stability can be either dependent or independent of the SBF complex. The SBF-dependent pathway requires downregulation of SBF complex levels and may thereby reroute the transcriptional program in favor of greater microtubule stability. This pathway can be triggered by overexpression of Fcp1p, a phosphatase in the general transcription machinery, or by expression of an allele of SWI6that is associated with reduced transcription from SBF-controlled promoters. The SBF-independent pathway is activated by a constitutively nuclear allele of Swi6p. Our results introduce novel roles in microtubule stability for genes whose participation in the process may be masked under normal conditions yet nonetheless acquire a dominant role when microtubule stability is compromised.

The integrity of mitosis is dependent upon strict regulation of microtubule stability and dynamics. Although much information has been accumulated on regulators of the microtubule cytoskeleton, our knowledge of the specific pathways involved is still limited. Here we designed genetic screens to identify regulators of microtubule stability that are dispensable in the wild type yet become essential under microtubule-disrupting conditions. We found that the transcriptional cofactor Swi6p and activator Swi4p, as well as the G2/M-specific cyclin Clb2p, are required in a microtubule-destabilizing environment. Swi6p and Swi4p can combine as a transcriptional complex, called the SBF complex (SBF for Swi4/6 cell cycle box [SCB]-binding factor) that is functionally homologous to the metazoan DP1/2-E2F complex and that controls the G1/S transition through the genes it regulates. We show that Swi6p's contribution to microtubule stability can be either dependent or independent of the SBF complex. The SBF-dependent pathway requires downregulation of SBF complex levels and may thereby reroute the transcriptional program in favor of greater microtubule stability. This pathway can be triggered by overexpression of Fcp1p, a phosphatase in the general transcription machinery, or by expression of an allele of SWI6 that is associated with reduced transcription from SBF-controlled promoters. The SBF-independent pathway is activated by a constitutively nuclear allele of Swi6p. Our results introduce novel roles in microtubule stability for genes whose participation in the process may be masked under normal conditions yet nonetheless acquire a dominant role when microtubule stability is compromised.