Fertility preservation after gonadotoxic treatments for cancer and autoimmune diseases.

BACKGROUND: The indications for fertility preservation (FP) have expanded. A few patients who underwent gonadotoxic treatment did not have the opportunity to receive FP, leading to concerns that these patients may develop premature ovarian insufficiency. However, the usefulness of FP in women with reduced ovarian reserve has also been questioned. Progestin-primed ovarian stimulation can improve the controlled ovarian stimulation (COS) protocol, but there is limited data on the efficacy of FP with progestin-primed ovarian stimulation. METHODS: We conducted a prospective study of 43 women with cancer or autoimmune diseases before and after gonadotoxic treatment at the reproductive unit of Keio University Hospital, counselled between 1 January 2018 and 31 December 2021. After counselling, informed consent was obtained for FP from 43 patients, with those who underwent gonadotoxic treatment of the primary disease being prioritised. Gonadotropin-releasing hormone analogue or progestin was used to suppress luteinising hormone in COS before or after gonadotoxic treatment. The number of cryopreserved mature oocytes was the primary outcome. RESULTS: Forty-three patients and 67 assisted reproductive technology cycles were included in the analysis. The median age at entry was 32 [inter quartile range (IQR), 29-37] years. All patients in the post-gonadotoxic treatment group had their oocytes frozen. Gonadotoxic treatment resulted in fewer oocytes [median 3 (IQR 1-4); pre-gonadotoxic treatment group: five patients, 13 cycles] vs. median 9 (IQR 5-14; pre-gonadotoxic treatment group: 38 patients, 54 cycles; P < 0.001). Although anti-Müllerian hormone levels were lower in the post-gonadotoxic treatment group (n = 5, 13 cycles, median 0.29 (IQR 0.15-1.04) pg/mL) than in the pre-gonadotoxic treatment group (n = 38, 54 cycles, median 1.89 (IQR 1.15-4.08) pg/mL) (P = 0.004), oocyte maturation rates were higher in the post-gonadotoxic treatment group [median 100 (IQR 77.5-100) %] than in the pre-gonadotoxic group [median 90.3 (IQR 75.0-100) %; P = 0.039]. Five patients in the pre-gonadotoxic treatment group had their cryopreserved embryos thawed, of which three had live births. CONCLUSIONS: Oocytes obtained for FP from women with cancer or autoimmune disease for FP are of satisfactory quality, regardless of whether they are obtained post-gonadotoxic treatment or COS protocols.

Artificial oocyte activation using Ca2+ ionophores following intracytoplasmic sperm injection for low fertilization rate.

This large multi-center retrospective study examined whether artificial oocyte activation (AOA) using Ca2+ ionophore following ICSI improves the live birth rate for couples with previous ICSI cycles of unexplained low fertilization rate. In this large-scale multi-center retrospective study conducted in Japan, data were collected from Keio University and 17 collaborating institutions of the Japanese Institution for Standardizing Assisted Reproductive Technology. Between January 2015 and December 2019, 198 couples were included in this study. Oocytes for both the intervention and control groups were procured from the same pool of couples. Oocytes obtained from ICSI cycles with no or low fertilization rate (<50%) with unknown causes were included in the control (conventional ICSI) group while oocytes procured from ICSI cycles followed by performing AOA were assigned to the intervention (ICSI-AOA) group. Those fertilized with surgically retrieved sperm were excluded. ICSI-AOA efficacy and safety were evaluated by comparing these two groups. Live birth rate was the primary outcome. The ICSI-AOA group (2,920 oocytes) showed a significantly higher live birth per embryo transfer rate (18.0% [57/316]) compared to that of the conventional ICSI group with no or low fertilization rate (1,973 oocytes; 4.7% [4/85]) (odds ratio 4.5, 95% confidence interval 1.6-12.6; P<0.05). A higher live birth rate was observed in younger patients without a history of oocyte retrieval. Miscarriage, preterm delivery, and fetal congenital malformation rates were similar between the two groups. ICSI-AOA may reduce fertilization failure without increasing risks during the perinatal period. AOA may be offered to couples with an ICSI fertilization rate < 50%.

Morphometric assessment of blastocysts: relationship with the ongoing pregnancy rate.

Objective: To explore a morphometric grading system for blastocysts that is associated with ongoing pregnancy. Design: Cross-sectional study. Setting: None. Patientss: All consecutive vitrified blastocysts at our center from July 2018 to November 2021 that were transferred in single blastocyst transfer cycles until January 2022. Interventions: None. Main Outcome Measures: The ongoing pregnancy rate after a single vitrified-warmed blastocyst transfer. Interobserver agreement on morphometric values among embryologists. Results: Three morphometric variables (blastocyst diameter, area of inner cell mass [ICM], and the estimated trophectoderm cell count) were used to evaluate the expansion, ICM, and trophectoderm morphology. During the study period, 585 blastocysts were involved in this study. Of the 3 morphometric variables, ICM area (per 500 µm2, adjusted odds ratio, 1.19; 95% confidence interval, 1.09-1.30) and estimated trophectoderm cell count (per 10 cells, adjusted odds ratio, 1.25; 95% confidence interval, 1.12-1.39) were significantly associated with the ongoing pregnancy rate after adjustment for confounding factors. The ongoing pregnancy rate was 2.0% (1/49) with an ICM area of <2,500 µm2 and the estimated trophectoderm cell count <70. The ongoing pregnancy rate reached 47.8% (22/46) when the ICM area and the estimated trophectoderm cell count were >3,500 µm2 and >110, respectively. Interobserver agreement on the blastocyst diameter, ICM area, and the estimated trophectoderm cell count was excellent-to-good among 5 embryologists (intraclass correlation coefficients: 0.99, 0.87, and 0.91, respectively). Conclusions: Morphometric values of ICM and trophectoderm are promising predictors of pregnancy success. The high reproducibility suggests that the morphometric variables will contribute to identifying blastocysts with the highest developmental potential as well as those that will not result in a successful pregnancy.

Evaluation of sperm head shape at high magnification revealed correlation of sperm DNA fragmentation with aberrant head ellipticity and angularity.

OBJECTIVE: To test for an association between DNA fragmentation and head shape at high magnification in fresh motile spermatozoa. DESIGN: Observational study. SETTING: Academic tertiary care center. PATIENT(S): A total of 60 men in our assisted reproductive program. INTERVENTION(S): Quantifying sperm head shape using elliptic Fourier analysis, and detecting DNA fragmentation by use of a terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. MAIN OUTCOME MEASURE(S): Correlation between percentage of spermatozoa with abnormal head shape and percentage of DNA fragmentation. RESULT(S): Elliptic Fourier analysis decomposed sperm head shapes into four quantitative parameters: ellipticity, anteroposterior (AP) symmetry, lateral symmetry, and angularity. The DNA fragmentation was statistically significantly correlated with abnormal angularity, and moderately with abnormal ellipticity but not with abnormal AP symmetry or lateral symmetry. Forward stepwise multiple logistic regression analysis revealed a statistically significantly higher percentage of DNA fragmentation in spermatozoa with abnormal ellipticity and abnormal angularity than in spermatozoa with normal-shaped head (6.1% and 5.4% vs. 2.8%). Spermatozoa with large nuclear vacuoles also correlated with sperm DNA fragmentation, and had a statistically significantly higher percentage of DNA fragmentation (4.7%). CONCLUSION(S): Among the morphologic features of the sperm head, abnormal ellipticity, angularity, and large nuclear vacuoles are associated with DNA fragmentation.

Internal selection against the evolution of left-right reversal.

Among metazoan species, left-right reversals in primary asymmetry have rarely gone to fixation. This suggests that a general mechanism suppresses the evolution of polarity reversal. Most metazoans appear externally symmetric and reproduce by external fertilization or copulation with genitalia located in the midline. Thus, reversal should generate little exogenous disadvantage when interacting with the external environment or in mating with the common wild-type. Accordingly, an endogenously caused fitness reduction may be responsible for the general absence of reversed species. However, how this selection operates is little understood. Phenotypic changes associated with reversal are usually inseparable from zygotic pleiotropy. By exploiting hermaphroditism and the maternal inheritance of left-right polarity, we generated dextral and sinistral snails that share the same zygotic genotype. Before hatching, these sinistrals developed lethal morphological anomalies more frequently than dextrals. Their shell shape at maturity differed from the mirror image of the dextral shell. These interchiral differences demonstrate pleiotropy in maternal effects of the polarity or linked genes. Variation in interchiral differences between parental crosses suggests the presence of epistatic variation in relative performance of sinistrals. Our results show that internal selection operates against polarity reversal, and we suggest that this is due to changes in blastomere configuration.

Maternal Inheritance of racemism in the terrestrial snail Bradybaena similaris.

In metazoan animals, almost every known mutation of visceral asymmetry, which presents the polarity of primary asymmetry established in early development, reverses development in only about half or fewer of homozygotes. However, in pulmonate snails, the dextral and sinistral alleles are traditionally known to determine the polarity of offspring with complete dominance, and thus, each parent should produce either dextral or sinistral progeny. Contrary to this expectation, we found a mutant that produces both chiral morphs (enantiomorphs) within the same clutches in Bradybaena similaris. This study demonstrates that the consistent production of both enantiomorphs is determined by a maternal effect of a recessive allele, which probably randomizes the polarity. In snails that copulate simultaneously and reciprocally, a left-right reversed strain cannot usually be established or rescued from inbreeding depression by ad hoc outbreeding because a rarely found single mutant cannot reproduce due to great difficulties of mating with the wild type and selfing. Moreover, the rare recessive homozygote cannot easily be detected because it often exhibits the wild-type phenotype in maternal inheritance and breeding difficulty hampers genotyping it by phenotyping its progeny. The present strain established by virtue of rare advantages will, therefore, provide unique opportunities to investigate whole-body enantiomorphs.

Fitness consequences of reciprocally asymmetric hybridization between simultaneous hermaphrodites.

Depending on fitness consequences, hybridization may rescue Inbred populations; generate premating barriers, reproductive Interference, or hybrid species; or extinguish a species. However, the fitness of hybrids is unpredictable without direct quantification of their performance in fitness components across multiple generations. The land snails Bradybaena pellucida and B. similaris, which are Indigenous and non-Indigenous in Japan, respectively, copulate with each other simultaneously and reciprocally. However, only B. pellucida produces hybrids, because it ends mating by removing the penis before transferring a spermatophore, while B. similaris Inseminates B. pellucida. To evaluate the strength of an Intrinsic postzygotic barrier against the hybrids produced by B. pellucida, we conducted breeding experiments in the laboratory and measured six life-history traits: (1) growth rate, (2) body weight at maturity, (3) number of days to first oviposition after being permitted to mate, (4) clutch size, (5) fecundity, and (6) hatchability. We also calculated the relative intrinsic fitness based on five of these trait values (excluding clutch size). F(1) hybrids exhibited heterosis in growth rate, body weight at maturity and relative intrinsic fitness. F(2) hybrids also showed heterosis in body weight at maturity. Nevertheless, the F(2) hybrids produced significantly fewer progeny than the mid-point value of the parental species. Thus, the F(2) hybrids exhibited weak out-breeding depression in reproduction, offsetting their vigor in body size. These results indicate that only a weak postzygotic barrier, contrasting with strong F(1) heterosis, has evolved during genetic divergence of the two sibling species in allopatry.

The development and evolution of left-right asymmetry in invertebrates: lessons from Drosophila and snails.

The unique nature of body handedness, which is distinct from the anteroposterior and dorsoventral polarities, has been attracting growing interest in diverse biological disciplines. Recent research progress on the left-right asymmetry of animal development has focused new attention on the mechanisms underlying the development and evolution of invertebrate handedness. This exploratory review of currently available information illuminates the prospective value of Drosophila and pulmonate snails for innovative new research aimed at elucidating these mechanisms. For example, findings in Drosophila and snails suggest that an actin filament-dependent mechanism may be evolutionarily conserved in protostomes. The polarity conservation of primary asymmetry across most metazoan phyla, which visceral handedness represents, indicates developmental constraint and purifying selection as possible but unexplored mechanisms. Comparative studies using Drosophila and snails, which have the great advantages of using genetic and evolutionary approaches, will accelerate our understanding of the mechanisms governing the conservation and diversity of animal handedness.