Ovarian dysfunction in women with Turner syndrome

Exosome's role in ovarian disease pathogenesis and therapy; Focus on ovarian cancer and failure

In the eukaryotic system, exosomes are categorized as unique extracellular vesicles with dimensions ranging from 30 to 150 nm. These vesicles contain a variety of endogenous molecules, such as proteins, DNA, mRNA, microRNA, and circular RNA. They are essential for a wide range of metabolic events and have the potential to be used as therapeutic or diagnostic targets for a number of diseases, including ovarian diseases. By inducing changes in the surrounding environment, the donor exosomes transfer their contents to the receiving cells, so demonstrating the biological implications of major interactions between cells. Mesenchymal stem cells (MSCs) have produced exosomes have shown promise as a treatment for premature organ failure (POF or POI). Furthermore, exosomal transport has many complexities, and contributes to the pathophysiology of ovarian cancer by affecting cell growth, migration, metastastsis and etc. Owing to these facts, in this paper, we present the progress developed in the understanding of exosomes as a viable therapeutic avenue and indisputable prognostic targets in ovarian disorders.

Karyotype and phenotype association in Turner syndrome with non-mosaic X chromosome structural rearrangements: Systematic review

Turner syndrome is a chromosomal disorder, characterized by the partial or total deletion of one X chromosome, resulting in various karyotypes that presumably lead to different phenotypes. However, most studies find it difficult to predict phenotypes from karyotypes due to the presence of mosaicism. The purpose of this study is to clarify the relationship between karyotype and phenotype in Turner syndrome with non-mosaic X chromosome structural rearrangements. A systematic literature search was conducted using Medline and Embase classics plus Embase between 1947 and September 2023. A total of 487 Turner women with non-mosaic X chromosome structural rearrangements were included from the 69 studies. The prevalence of short stature was 72.4% in Turner syndrome with non-mosaic X chromosome structural rearrangements, 80.1% in the short arm deletion group (del (Xp)), 75% in the del(X)(p22.3) group, 65.8% in the del(X)(p21) and del(X)(p22) group, and 37.5% (20%-66.7%) in the long arm deletion group (del(Xq)). The prevalence of ovarian dysfunction was 78.8% in Turner syndrome with non-mosaic X chromosome structural rearrangements, 72.5% in the del (Xp) group, 27.6% in the del (X)(p22.3) group, 33.3% in the del (X)(p21) and del(X)(p22) group, and 94.6% in the del (Xq) group. The recognition of X chromosome breakpoints is useful in the management of Turner syndrome complications, since some phenotypes are unique depending on the deletion region. Ovarian dysfunction is significantly related to karyotype, so the identification of karyotypes in Turner syndrome is important for managing ovarian dysfunction and predicting future fertility.

Turner Syndrome where are we?

Turner syndrome (TS) results from the loss of one X chromosome in phenotypic females, leading to a range of complications such as short stature, cardiovascular issues, autoimmune disorders, metabolic imbalances, osteoporosis, neurocognitive deficits, hearing loss, abnormalities in endocrine functions, infertility, disruptions in bone metabolism, and neurocognitive deficits. These diverse clinical manifestations necessitate a comprehensive and multidisciplinary approach to diagnosis and management. Growth hormone therapy stands out as a fundamental treatment for addressing the challenges associated with TS. Ongoing clinical and genomic advancements contribute to an evolving understanding of TS, shedding light on its complexities and potential therapeutic interventions. Despite progress, further research is crucial to identify candidate pathways and critical biomarkers that can alleviate the syndrome's burden. By uncovering these insights, we aim to empower individuals with TS, enhancing their overall functioning and quality of life. In this review, we have explored the prevalent co-morbidities associated with TS, drawing insights from the current literature.

Reproductive health in Turner's syndrome: from puberty to pregnancy

Turner syndrome (TS) is a genetic pathology that affects about 1/2500 newborn females. Turner's syndrome is characterized by highly variable genetic anomalies that consist in a partial or complete deletion of the X sexual chromosome; it can be present as a monosomy or as a mosaicism with two o three different cellular lines. 50% of the patients with Turner's syndrome has a 45 XO karyotype while the remaining cases have karyotypes with mosaicism or X isochromosome or with partial or whole Y chromosome. This pathology is characterized by multiple anomalies that involve physical and cognitive development and in particular endocrine, cardiovascular, reproductive, auditive and visual systems. Integrity of the X chromosome in essential for fertility. In TS is accelerated germ cells apoptosis. About 30% of TS girls have some pubertal development, 10-20% undergo menarche and 2-8% go through spontaneous pregnancy. Women with TS should be informed about the risk of premature menopause and should be referred, if possible, to a specialist evaluation with a doctor expert in assisted reproductive techniques. In adolescents and in adults, Premature Ovarian Insufficiency (POI) can be evaluated clinically and biochemically with the classic combination of amenorrhea and elevated FSH concentrations (hypergonadotropic hypogonadism). However, in postpubertal adolescents and adult women, reproductive hormones may remain within the normal range before POI is clinically evident, despite significant depletion of the ovarian reserve. Today, reproductive medicine offers the opportunity of fertility preservation in women with premature ovarian insufficiency (POI). Two techniques have been suggested such as ovarian cortex cryopreservation and oocytes cryopreservation.

Should we perform oocyte accumulation to preserve fertility in women with Turner syndrome? A multicenter study and systematic review of the literature

STUDY QUESTION

Should we perform oocyte accumulation to preserve fertility in women with Turner syndrome (TS)?

SUMMARY ANSWER

The oocyte cryopreservation strategy is not well adapted for all TS women as their combination of high basal FSH with low basal AMH and low percentage of 46,XX cells in the karyotype significantly reduces the chances of freezing sufficient mature oocytes for fertility preservation.

WHAT IS KNOWN ALREADY

An oocyte cryopreservation strategy requiring numerous stimulation cycles is needed to preserve fertility in TS women, to compensate for the low ovarian response, the possible oocyte genetic alterations, the reduced endometrial receptivity, and the increased rate of miscarriage, observed in this specific population. The validation of reliable predictive biomarkers of ovarian response to hormonal stimulation in TS patients is necessary to help practitioners and patients choose the best-personalized fertility preservation strategy.

STUDY DESIGN, SIZE, DURATION

A retrospective bicentric study was performed from 1 January 2011 to 1 January 2023. Clinical and biological data from all TS women who have received from ovarian stimulation for fertility preservation were collected. A systematic review of the current literature on oocyte retrieval outcomes after ovarian stimulation in TS women was also performed (PROSPERO registration number: CRD42022362352).

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 14 TS women who had undergone ovarian stimulation for fertility preservation were included, representing the largest cohort of TS patients published to date (n = 14 patients, 24 cycles). The systematic review of the literature identified 34 additional TS patients with 47 oocyte retrieval outcomes after ovarian stimulation in 14 publications (n = 48 patients, n = 71 cycles in total).

MAIN RESULTS AND THE ROLE OF CHANCE

The number of cryopreserved mature oocytes on the first cycle for TS patients was low (4.0 ± 3.7). Oocyte accumulation was systematically proposed to increase fertility potential and was accepted by 50% (7/14) of patients (2.4 ± 0.5 cycles), leading to an improved total number of 10.9 ± 7.2 cryopreserved mature oocytes per patient. In the group who refused the oocyte accumulation strategy, only one patient exceeded the threshold of 10 mature cryopreserved oocytes. In contrast, 57.1% (4/7) and 42.9% (3/7) of patients who have underwent the oocyte accumulation strategy reached the threshold of 10 and 15 mature cryopreserved oocytes, respectively (OR = 8 (0.6; 107.0), P = 0.12; OR= 11 (0.5; 282.1), P = 0.13). By analyzing all the data published to date and combining it with our data (n = 48 patients, n = 71 cycles), low basal FSH and high AMH concentrations as well as a higher percentage of 46,XX cells in the karyotype were significantly associated with a higher number of cryopreserved oocytes after the first cycle. Moreover, the combination of low basal FSH concentration (<5.9 IU/l), high AMH concentration (>1.13 ng/ml), and the presence of 46,XX cells (>1%) was significantly predictive of obtaining at least six cryopreserved oocytes in the first cycle, representing objective criteria for identifying patients with real chances of preserving an adequate fertility potential by oocyte cryopreservation.

LIMITATIONS, REASONS FOR CAUTION

Our results should be analyzed with caution, as the optimal oocyte number needed for successful live birth in TS patients is still unknown due to the low number of reports their oocyte use in the literature to date.

WIDER IMPLICATIONS OF THE FINDINGS

TS patients should benefit from relevant clinical evaluation, genetic counseling and psychological support to make an informed choice regarding their fertility preservation technique, as numerous stimulation cycles would be necessary to preserve a high number of oocytes.

STUDY FUNDING/COMPETING INTEREST(S)

This research received no external funding. The authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.