Answer to Controversy: miR-10a Replacement Approaches Do Not Offer Protection against Chemotherapy-Induced Gonadotoxicity in Mouse Model.

It is well known that chemotherapeutic agents may lead to premature ovarian failure and infertility. Therefore, fertility preservation is highly recommended for female cancer survivors. Despite the currently available techniques, new, non-invasive methods need to be developed to protect the ovarian follicles during oncological treatments. MicroRNAs can be effective tools in this field, as they alter their expression during chemotherapy exposure, and hence they can be useful to minimize the off-target toxicity. Previously, we identified several miRNAs with an important role in newborn mouse ovaries exposed to chemotherapy; among them, the miR-10a was one of the most downregulated miRNAs. Given the controversial role of miR-10a in the ovarian function, we decided to investigate its implication in chemotherapy-induced gonadotoxicity. The downregulated levels of miR-10a were restored by a liposome system conjugated with a mimic miR-10a, and the overexpressed miR-10a prevented the upregulation of the targeted gene, phosphatase and tensin homolog (Pten). The apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) Assay and Bax expression quantification, while histological studies were also performed to evaluate the follicle count and development. Our results showed that the miR-10a replacement could not protect the ovaries from chemotherapy-induced apoptosis, whereas the targeting of Pten may affect the follicle activation via the phosphoinositide 3-kinase (PI3K)/PTEN/protein kinase B (AKT) pathway. Consequently, the application of miR-10a in fertility preservation is not recommended, and the role of miR-10a needs to be further elucidated.

GAPO syndrome: a new syndromic cause of premature ovarian insufficiency.

Premature ovarian insufficiency has the following causes: genetic, autoimmune, metabolic, infectious, and iatrogenic dysfunctions (including radiotherapy, chemotherapy and surgery). However, premature ovarian insufficiency remains without a definite cause in a substantial number of cases. This article describes GAPO syndrome in association with premature ovarian insufficiency, as well as a novel ANTXR1 gene mutation. Histopathological study of the ovaries of a woman with hypergonadotropic hypogonadism revealed extensive deposition of hyaline extracellular material, with bilateral parenchymal atrophy and follicular depletion. Molecular study revealed a novel ANTXR1 gene mutation. The homozygous c.378 + 3A > G transition at the consensus donor splice site of intron 4 was identified. Our results support the involvement of ANTRX1 gene mutations in deregulated extracellular matrix. In addition, our study identified a novel ANTXR1 mutation causing GAPO syndrome, indicating it as a new cause of early loss of ovarian function.

A girl with Hajdu-Cheney syndrome and premature ovarian failure.

Hajdu-Cheney syndrome is an autosomal dominant disorder characterized by acroosteolysis of the distal phalanges associated with digit abnormalities, distinctive craniofacial changes, dental anomalies, and a proportionate short stature. The pubertal development of children with Hajdu-Cheney syndrome is usually normal in the literature, although we here first describe a girl who was found to have Hajdu-Cheney syndrome accompanied with premature ovarian failure. She showed a follicle-stimulating hormone-dominant response on luteinizing hormone-releasing hormone test and did not show any sex differentiation abnormality or adrenal steroid hormone deficiency. On the basis of the findings in our patient, premature ovarian failure may be a complication of Hajdu-Cheney syndrome and thus an early endocrinological evaluation of patients is important.

Selected enquiries into the causation of premature ovarian failure.

In most species, reproductive senescence can be explained in the same general terms as physiological senescence. In fact, in some species rapid physiological senescence occurs on the completion of reproduction. The programme in women is unusual in that ovarian function comes to a relatively abrupt halt at 45-50 years of age, when the impact of somatic senescence on most other functions is minimal. Early reproductive senescence has been reported in other species (chimpanzees, macaques and toothed whales) but it is more attenuated and less abrupt. The proximate cause of physiological menopause seems to be oocyte depletion, but less obvious neuroendocrine changes precede or result from the gradual loss of oocytes. This is not surprising as many age-specific processes are controlled by hormones. Hormones provide a way for an animal to co-ordinate the ageing of different tissues. The failure to comprehend completely the reasons for the biological uniqueness of women makes the study of the more extreme examples of premature ovarian failure an important exercise. The premature loss of ovarian function in certain eukaryotic women highlights the role of those special maintenance and repair systems that must be functional in the selection process for healthy germ cells. The purpose of this article is to indicate selected areas of clinical and basic investigation that may provide clues to the mechanisms of untimely ageing of the human ovary. Studies of those human extremes with premature loss, or extended ovarian function, may provide critical insights into the unique discordance between somatic and reproductive senescence that is characteristic of normal women.