The reproductive lifespan in humans is regulated by a delicate cyclical balance between follicular recruitment and atresia in the ovary. The majority of the small antral follicles present in the... Show moreThe reproductive lifespan in humans is regulated by a delicate cyclical balance between follicular recruitment and atresia in the ovary. The majority of the small antral follicles present in the ovary are progressively lost through atresia without reaching dominance, but this process remains largely underexplored. In our study, we investigated the characteristics of atretic small antral follicles and proposed a classification system based on molecular changes observed in granulosa cells, theca cells, and extracellular matrix deposition. Our findings revealed that atresia spreads in the follicle with wave-like dynamics, initiating away from the cumulus granulosa cells. We also observed an enrichment of CD68+ macrophages in the antrum during the progression of follicular atresia. This work not only provides criteria for classifying three stages of follicular atresia in small antral follicles in the human ovary but also serves as a foundation for understanding follicular degeneration and ultimately preventing or treating premature ovarian failure. Understanding follicular remodeling in the ovary could provide a means to increase the number of usable follicles and delay the depletion of the follicular reserve, increasing the reproductive lifespan. Show less
Human ovarian folliculogenesis is a highly regulated and complex process. Characterization of follicular cell signatures during this dynamic process is important to understand follicle fate (to... Show moreHuman ovarian folliculogenesis is a highly regulated and complex process. Characterization of follicular cell signatures during this dynamic process is important to understand follicle fate (to grow, become dominant, or undergo atresia). The transcriptional signature of human oocytes and granulosa cells (GCs) in early-growing and ovulatory follicles have been previously described; however, that of oocytes with surrounding GCs in small antral follicles have not been studied yet. Here, we have generated a unique dataset of single-cell transcriptomics (SmartSeq2) consisting of the oocyte with surrounding GCs from several individual (non-dominant) small antral follicles isolated from adult human ovaries. We have identified two main types of (healthy) follicles, with a distinct oocyte and GC signature. Using the CellphoneDB algorithm, we then investigated the bi-directional ligand-receptor interactions regarding the transforming growth factor-beta (TGF beta)/bone morphogenetic protein (BMP), wingless-type (MMTV)-integration site (WNT), NOTCH, and receptor tyrosine kinases (RTK) signaling pathways between oocyte and GCs within each antral follicle type. Our work not only revealed the diversity of small antral follicles, but also contributes to fill the gap in mapping the molecular landscape of human folliculogenesis and oogenesis. Show less
Spaan, M.; Belt-Dusebout, A.W. van den; Lambalk, C.B.; H.H. van boven; Schats, R.; Kortman, M.; ... ; Leeuwen, F.E. van 2021
Background: Long-term effects of assisted reproductive technology (ART) on ovarian tumor risk are unknown. Methods: This nationwide cohort study comprises 30 625 women who received ovarian... Show moreBackground: Long-term effects of assisted reproductive technology (ART) on ovarian tumor risk are unknown. Methods: This nationwide cohort study comprises 30 625 women who received ovarian stimulation for ART in 1983-2000 and 9988 subfertile women not treated with ART. Incident invasive and borderline ovarian tumors were ascertained through linkage with the Netherlands Cancer Registry and the Dutch Pathology Registry until July 2018. Ovarian tumor risk in ART-treated women was compared with risks in the general population and the subfertile non-ART group. Statistical tests were 2-sided. Results: After a median follow-up of 24 years, 158 invasive and 100 borderline ovarian tumors were observed. Ovarian cancer risk in the ART group was increased compared with the general population (standardized incidence ratio [SIR] = 1.43, 95% confidence interval [CI] = 1.18 to 1.71) but not when compared with the non-ART group (age- and parity-adjusted hazard ratio [HR] = 1.02, 95% CI = 0.70 to 1.50). Risk decreased with higher parity and with a larger number of successful ART cycles (resulting in childbirth, Ptrend = .001) but was not associated with the number of unsuccessful ART cycles. Borderline ovarian tumor risk was increased in ART-treated women compared with the general population (SIR = 2.20, 95% CI = 1.66 to 2.86) and with non-ART women (HR = 1.84, 95% CI = 1.08 to 3.14). Risk did not increase with more ART cycles or longer follow-up time. Conclusions: Increased ovarian cancer risk in ART-treated women compared with the general population is likely explained by nulliparity rather than ART treatment. The increased risk of borderline ovarian tumors after ART must be interpreted with caution because no dose-response relationship was observed. Show less
Hoekman, E.J.; Louwe, L.A.; Rooijers, M.; Westerlaken, L.A.J. van der; Klijn, N.F.; Pilgram, G.S.K.; ... ; Hilders, C.G.J.M. 2020
Introduction The likelihood of survival after cancer treatment among young women with cancer has increased considerably, quality of life after treatment has drawn more attention. However, in young... Show moreIntroduction The likelihood of survival after cancer treatment among young women with cancer has increased considerably, quality of life after treatment has drawn more attention. However, in young fertile women, fertility preservation is an important issue with regard to quality of life. One of the options of fertility preservation is ovarian tissue cryopreservation. The purpose of this follow-up study is to present our clinical experiences and evaluate the long-term follow up of ovarian cryopreservation to improve future patient selection. Material and methods From July 2002 to December 2015 at the Leiden University Hospital, the Netherlands, 69 young women underwent ovarian tissue cryopreservation when they were at risk of iatrogenic premature ovarian insufficiency. Follow-up data with regard to ovarian function were obtained until October 2018, from medical records and questionnaires. Results Of the 69 women in whom ovarian tissue cryopreservation was performed, 12 died (15.9%), 57 were approached to participate, of which 6 were lost to follow up. The indications for ovarian tissue cryopreservation were malignant (81.1%) and benign (18.9%) diseases in which gonadotoxic treatment was scheduled. In total, twenty women (39.2%) are known to have premature ovarian insufficiency due to gonadotoxic treatment. Fifteen women conceived spontaneously, and delivered 25 babies. In this cohort, the usage rate of autotransplantation is 8.7% (7/69). In total, nine autotransplantations of cryopreserved ovarian tissue were performed in seven patients (of which 1 ovarian tissue cryopreservation was performed in another hospital) after which 6 babies were born to four women, giving a live-birth rate of 57%. Conclusions Ovarian tissue cryopreservation followed by autotransplantation is an effective method to restore fertility (live-birth rate of 57%). The usage rate of 8.7% (6/69) indicates that more knowledge about the risk of premature ovarian insufficiency after gonadotoxic treatment is needed to be able to offer ovarian tissue cryopreservation more selectively. Show less
Tweel, M.M. van den; Klijn, N.F.; Pool, J.D.N.D. de; Westerlaken, L.A.J. van der; Louwe, L.A. 2019
This retrospective cohort study examines the association between previous mode of delivery and subsequent live birth rate in women who become pregnant after in vitro fertilization (IVF) or intra... Show moreThis retrospective cohort study examines the association between previous mode of delivery and subsequent live birth rate in women who become pregnant after in vitro fertilization (IVF) or intra cytoplasmic sperm injection (ICSI) after their first delivery. The study included 112 women with a previous caesarean section and 418 women with a previous vaginal delivery, and a total of 1588 embryo transfers between January 2005 and June 2016 (Leiden University Medical Centre, the Netherlands). The mean age was 35 years and mean number of embryos transferred per attempt, 1.18. The study population included a total of 429 pregnancies resulting in 296 live births. The crude odds ratio for a subsequent live birth per embryo transfer was 0.60 (CI; 0.44 to 0.83, p = 0.002) in women with a previous caesarean section compared to women with a previous vaginal delivery. After adjustment for age, fresh/frozen-thawed embryo transfer and quality of the embryo, the odds ratio was 0.64 (CI; 0.46 to 0.89, p = 0.01). It was concluded that in subfertile women trying to achieve a subsequent pregnancy with IVF or ICSI, a history of caesarean section was associated with a reduced live birth rate per embryo transfer compared to women with a history of one previous vaginal delivery. Show less
Pool, J.D.N.D. de; Berg, S.A.A. van den; Pilgram, G.S.K.; Ballieux, B.E.P.B.; Westerlaken, L.A.J. van der 2018
Genetic mouse model (39,XO) for human Turner Syndrome (45,XO) harboring either a single maternally inherited (Xm) or paternally inherited (Xp) chromosome show a pronounced difference in survival... Show moreGenetic mouse model (39,XO) for human Turner Syndrome (45,XO) harboring either a single maternally inherited (Xm) or paternally inherited (Xp) chromosome show a pronounced difference in survival rate at term. However, a detailed comparison of XmO and XpO placentas to explain this difference is lacking. We aimed to investigate the morphological and molecular differences between XmO and XpO term mouse placentas. We observed that XpO placentas at term contained a significantly larger area of glycogen cells (GCs) in their outer zone, compared to XmO, XX and XY placentas. In addition, the outer zone of XpO placentas showed higher expression levels of lactate dehydrogenase (Ldha) than XmO, XX and XY placentas, suggestive of increased anaerobic glycolysis. In the labyrinth, we detected significantly lower expression level of trophectoderm (TE)-marker keratin 19 (Krt19) in XpO placentas than in XX placentas. The expression of other TE-markers was comparable as well as the area of TE-derived cells between XO and wild-type labyrinths. XpO placentas exhibited specific defects in the amount of GCs and glucose metabolism in the outer zone, suggestive of increased anaerobic glycolysis, as a consequence of having inherited a single Xp chromosome. In conclusion, the XpO genotype results in a more severe placental phenotype at term, with distinct abnormalities regarding glucose metabolism in the outer zone. Show less
He, N.N.; Iperen, L. van; Jong, D. de; Szuhai, K.; Helmerhorst, F.M.; Westerlaken, L.A.J. van der; Lopes, S.M.C.D. 2017
