Objective: To evaluate in vitro maturation (IVM) efficacy and oocyte retrieval rates after ovarian tissue cryopreservation in young premenarche girls facing chemo-and radiotherapy. Design: A retrospective cohort study. Setting: University-affiliated tertiary medical center. Patient(s): A total of 84 chemotherapy-naïve patients ages 0-18 years referred for fertility preservation between 2004 and 2017: 33 premenarche and 51 postmenarche patients. Intervention(s): None. Main Outcome Measure(s): IVM in the pre-and postmenarche groups and in the subgroups of very young (up to age 5 years) and older (5-10 years) premenarche girls. Results: The number of oocytes retrieved did not significantly differ between the postmenarche and premenarche groups (10.8 AE 8.5 and 8.1 AE 6.8, respectively). However, the overall IVM rate was significantly higher in the postmenarche group (28.2% vs. 15.5%, respectively; odds ratio ¼ 0.47). A separate analysis for patients up to 5 years of age demonstrated significantly lower oocyte yield compared with the older (5-10 years) premenarche girls (4.7 AE 5.2 vs.10.3 AE 7.0 oocytes, respectively) and much lower IVM rates (4.9% and 18.2%, respectively). Correlation of age with number of retrieved and matured oocytes showed a positive significant correlation (r ¼ 0.45 and r ¼ 0.64, respectively). Conclusions: IVM performed after ovarian tissue cryopreservation in premenarche girls and specifically in very young girls (4 years and younger) yields substantially decreased maturation rates compared with postmenarche patients, raising a question as to the utility of current IVM technique in this age group. Further studies are required to assess modification of the IVM technique for young girls. (Fertil Steril Ò 2019;112:315-22. Ó2019 by American Society for Reproductive Medicine.) El resumen está disponible en Español al final del artículo.

Iron chelating agents, which permeate through erythrocytic and parasite membranes, are effective against Plasmodium falciparum in vitro. However, the protective effect in humans is transient. We examined the antiplasmodial capacity of several iron chelators in vitro and in vivo. The chelators 3/3hb/2m and 3/2hb/b (together, MoB) were more effective against P. falciparum in vitro than desferrioxamine (DFO) and Salicylaldehyde isonicotinoyl hydrazone (SIH) (together, DoS). Despite similar pharmacokinetics of all iron chelators, mice infected with Plasmodium vinckei and treated with MoB succumbed to malaria, whereas DoS-treated mice survived. However, even in the surviving mice, peak parasitemias were above 30%. These results indicate that the direct effects of the drugs on the parasites were not responsible alone for the complete recovery of the mice. We suggest that the recovery is related to differential effects of the drugs on various immune functions. We concentrated on the effect of the iron chelators on B cell and T cell proliferation and on allogeneic stimulation (MLR), interleukin-10 (IL-10), gamma-interferon (gamma-IFN), tumor necrosis factor-alpha (TNF-alpha), and radical production. All the iron chelators examined inhibited the in vitro proliferation of B cells and T cells, and MLR. This may explain why iron chelators are only slightly efficient in treating human malaria. However, the inhibitory effects of MoB on B cell and T cell proliferation and on MLR were more pronounced than those of DoS. In addition, the release of free radicals by effector cells was inhibited to a greater extent by MoB than by DoS. These results may explain why MoB, which was more efficient in vitro, was not effective in vivo. The DoS effects on the in vitro secretion of cytokines correlate with their in vivo effect; there was a decrease of IL-10 and a parallel increase in gamma-IFN and TNF-alpha production by human mononuclear cells. MoB, which could not rescue the animals from malaria, did not affect IL-10 and TNF-alpha, but reduced gamma-IFN levels. Identical results were obtained when using monocytes instead of mononuclear cells (except for gamma-IFN, which is not produced by monocytes). Our results indicate that an iron chelator, or any antiparasitic drug that kills the parasites in vitro, should also be selected for further evaluation on the basis of its reaction with immune components; it should not interfere with crucial protective immunological processes, but it may still alleviate parasitemia by positive immune modulation.

In vitro maturation of oocytes from antral follicles seen during tissue harvesting is a fertility preservation technique with potential advantages over ovarian tissue cryopreservation (OTC), as mature frozen and later thawed oocyte used for fertilization poses decreased risk of malignant cells re-seeding, as compared to ovarian tissue implantation. We previously demonstrated that in vitro maturation (IVM) performed following OTC in fertility preservation patients, even in pre-menarche girls, yields a fair amount of oocytes available for IVM and freezing for future use. We conducted a retrospective cohort study, evaluating IVM outcomes in chemotherapy naïve patients referred for fertility preservation by OTC that had oocyte collected from the medium with attempted IVM. A total of 133 chemotherapy naïve patients aged 1–35 years were included in the study. The primary outcome was IVM rate in the different age groups – pre-menarche (1–5 and ≥6 years), post-menarche (menarche-17 years), young adults (18–24 years) and adults (25–29 and 30–35 years). We demonstrate a gradual increase in mean IVM rate in the age groups from 1 to 25 years [4.6% (1–5 years), 23.8% (6 years to menarche), and 28.4% (menarche to 17 years)], with a peak of 38.3% in the 18–24 years group, followed by a decrease in the 25–29 years group (19.3%), down to a very low IVM rate (8.9%) in the 30–35 years group. A significant difference in IVM rates was noted between the age extremes – the very young (1–5 years) and the oldest (30–35 years) groups, as compared with the 18–24-year group (p < 0.001). Importantly, number of oocytes matured, percent of patients with matured oocytes, and overall maturation rate differed significantly (p < 0.001). Our finding of extremely low success rates in those very young (under 6 years) and older (≥30 years) patients suggests that oocytes retrieved during OTC prior to chemotherapy have an optimal window of age that shows higher success rates, suggesting that oocytes may have an inherent tendency toward better maturation in those age groups.

Pre-pubertal oocytes are still dormant. They are arrested in a GV state and do not undergo meiotic divisions naturally. A multitude of molecular pathways are changed and triggered upon initiation of puberty. It is not yet clear which epigenetic events occur in oocytes upon pubertal transition, and how significant these epigenetic events may be. We evaluated epigenetic marker levels in mouse pre-pubertal and post-pubertal female oocytes. In addition, we evaluated H3K9me2 levels in human oocytes collected from fertility preservation patients, comparing the levels between pre-pubertal patients and post-pubertal patients. The chromatin structure shows a lower number of chromocenters in mouse post-pubertal oocytes in comparison to pre-pubertal oocytes. All heterochromatin marker levels checked (H3K9me2, H3K27me3, H4K20me1) significantly rise across the pubertal transition. Euchromatin markers vary in their behavior. While H3K4me3 levels rise with the pubertal transition, H3K27Ac levels decrease with the pubertal transition. Treatment with SRT1720 [histone deacetylase (HDAC) activator] or overexpression of heterochromatin factors does not lead to increased heterochromatin in pre-pubertal oocytes. However, treatment of pre-pubertal oocytes with follicle-stimulating hormone (FSH) for 24 h - changes their chromatin structure to a post-pubertal configuration, lowers the number of chromocenters and elevates their histone methylation levels, showing that hormones play a key role in chromatin regulation of pubertal transition. Our work shows that pubertal transition leads to reorganization of oocyte chromatin and elevation of histone methylation levels, thus advancing oocyte developmental phenotype. These results provide the basis for finding conditions for in-vitro maturation of pre-pubertal oocytes, mainly needed to artificially mature oocytes of young cancer survivors for fertility preservation purposes.

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