LH prevents cisplatin-induced apoptosis in oocytes and preserves female fertility in mouse

Chemotherapy drug combinations induced maternal ovarian damage and long-term effect on fetal reproductive system in mice

With the postponement of female reproductive age and the higher incidence of cancer in young people, fertility preservation has become increasingly important in childbearing age. Chemotherapy during pregnancy is crucial for maternal cancer treatments and fetal outcomes. It is a need to further study ovarian damage caused by chemotherapy drug combinations and long-term effects on offspring development, and a detailed understanding of side effects of chemotherapy drugs. In this study, chemotherapy drug combinations significantly impacted on ovarian function, especially epirubicin/cyclophosphamide (EC) combination led to an unbalance in the development of the left and right ovary. Exposure to EC and cisplatin/paclitaxel (TP) increased the number of progenitor follicles while decreased the count of antral follicles and corpora luteum. As to the estrus cycle, EC exposure resulted in a longer estrus period and diestrus period, while TP exposure only extended the diestrus period. EC and TP affected steroid biosynthesis by reducing the expression of SF1 and P450arom.γ-H2AX was detected in both EC and TP exposure groups. As to the impact on the offspring from 4T1 tumor-bearing pregnant mice injected with EC, no significant difference was observed in the physical and neurological development compared to the control, but the ovarian weights, estrus cycles of the offspring were significantly different. Chemotherapy drug combinations exhibit ovarian toxicity, not only causing direct damage on the follicle cells but also disrupting steroid biosynthesis. The reproductive system of offspring from maternal tumor-bearing mice exposed to chemotherapy drugs was observed disorder, but the concrete mechanism still needs further exploration.

Discovery and evaluation of novel spiroheterocyclic protective agents via a SIRT1 upregulation mechanism in cisplatin-induced premature ovarian failure

Currently, no effective treatment exists for premature ovarian failure (POF). To obtain compounds with protective effects against POF, we aimed to design and synthesize a series of spiroheterocyclic protective agents with a focus on minimizing toxicity while enhancing their protective effect against cisplatin-induced POF. This was achieved through systematic modifications of Michael receptors and linkers within the molecular structure of 1,5-diphenylpenta-1,4-dien-3-one analogs. To assess the cytotoxicity and activity of these compounds, we constructed quantitative conformational relationship models using an artificial intelligence random forest algorithm, resulting in R2 values exceeding 0.87. Among these compounds, j2 exhibited optimal protective activity. It significantly increased the survival of cisplatin-injured ovarian granulosa KGN cells, improved post-injury cell morphology, reduced apoptosis, and enhanced cellular estradiol (E2) levels. Subsequent investigations revealed that j2 may exert its protective effect via a novel mechanism involving the activation of the SIRT1/AKT signal pathway. Furthermore, in cisplatin-injured POF in rats, j2 was effective in increasing body, ovarian, and uterine weights, elevating the number of follicles at all levels in the ovary, improving ovarian and uterine structures, and increasing serum E2 levels in rats with cisplatin-injured POF. In conclusion, this study introduces a promising compound j2 and a novel target SIRT1 with substantial protective activity against cisplatin-induced POF.

Advances in the role of resveratrol and its mechanism of action in common gynecological tumors

The incidence of common gynecological malignancies remains high, with current treatments facing multiple limitations and adverse effects. Thus, continuing the search for safe and effective oncologic treatment strategies continues. Resveratrol (RES), a natural non-flavonoid polyphenolic compound, is widely found in various plants and fruits, such as grapes, Reynoutria japonica Houtt., peanuts, and berries. RES possesses diverse biological properties, including neuroprotective, antitumor, anti-inflammatory, and osteoporosis inhibition effects. Notably, RES is broadly applicable in antitumor therapy, particularly for treating gynecological tumors (cervical, endometrial, and ovarian carcinomas). RES exerts antitumor effects by promoting tumor cell apoptosis, inhibiting cell proliferation, invasion, and metastasis, regulating tumor cell autophagy, and enhancing the efficacy of antitumor drugs while minimizing their toxic side effects. However, comprehensive reviews on the role of RES in combating gynecological tumors and its mechanisms of action are lacking. This review aims to fill this gap by examining the RES antitumor mechanisms of action in gynecological tumors, providing valuable insights for clinical treatment.

Gonadotropin Activity during Early Folliculogenesis and Implications for Polycystic Ovarian Syndrome and Premature Ovarian Insufficiency: A Narrative Review

Female fertility depends on the ovarian reserve of follicles, which is determined at birth. Primordial follicle development and oocyte maturation are regulated by multiple factors and pathways and classified into gonadotropin-independent and gonadotropin-dependent phases, according to the response to gonadotropins. Folliculogenesis has always been considered to be gonadotropin-dependent only from the antral stage, but evidence from the literature highlights the role of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) during early folliculogenesis with a potential role in the progression of the pool of primordial follicles. Hormonal and molecular pathway alterations during the very earliest stages of folliculogenesis may be the root cause of anovulation in polycystic ovary syndrome (PCOS) and in PCOS-like phenotypes related to antiepileptic treatment. Excessive induction of primordial follicle activation can also lead to premature ovarian insufficiency (POI), a condition characterized by menopause in women before 40 years of age. Future treatments aiming to suppress initial recruitment or prevent the growth of resting follicles could help in prolonging female fertility, especially in women with PCOS or POI. This review will briefly introduce the impact of gonadotropins on early folliculogenesis. We will discuss the influence of LH on ovarian reserve and its potential role in PCOS and POI infertility.

Gynotoxic Effects of Chemotherapy and Potential Protective Mechanisms

Chemotherapy is one of the leading cancer treatments. Unfortunately, its use can contribute to several side effects, including gynotoxic effects in women. Ovarian reserve suppression and estrogen deficiency result in reduced quality of life for cancer patients and are frequently the cause of infertility and early menopause. Classic alkylating cytostatics are among the most toxic chemotherapeutics in this regard. They cause DNA damage in ovarian follicles and the cells they contain, and they can also induce oxidative stress or affect numerous signaling pathways. In vitro tests, animal models, and a few studies among women have investigated the effects of various agents on the protection of the ovarian reserve during classic chemotherapy. In this review article, we focused on the possible beneficial effects of selected hormones (anti-Müllerian hormone, ghrelin, luteinizing hormone, melatonin), agents affecting the activity of apoptotic pathways and modulating gene expression (C1P, S1P, microRNA), and several natural (quercetin, rapamycin, resveratrol) and synthetic compounds (bortezomib, dexrazoxane, goserelin, gonadoliberin analogs, imatinib, metformin, tamoxifen) in preventing gynotoxic effects induced by commonly used cytostatics. The presented line of research appears to provide a promising strategy for protecting and/or improving the ovarian reserve in the studied group of cancer patients. However, well-designed clinical trials are needed to unequivocally assess the effects of these agents on improving hormonal function and fertility in women treated with ovotoxic anticancer drugs.

Association of platinum-based chemotherapy with live birth and infertility in female survivors of adolescent and young adult cancer

OBJECTIVE

To estimate the effect of platinum-based chemotherapy on live birth (LB) and infertility after cancer, in order to address a lack of treatment-specific fertility risks for female survivors of adolescent and young adult cancer, which limits counseling on fertility preservation decisions.

DESIGN

Retrospective cohort study.

SETTING

US administrative database.

PATIENTS

We identified incident breast, colorectal, and ovarian cancer cases in females aged 15-39 years who received platinum-based chemotherapy or no chemotherapy and matched them to females without cancer.

INTERVENTION

Platinum-based chemotherapy.

MAIN OUTCOME MEASURES

We estimated the effect of chemotherapy on the incidence of LB and infertility after cancer, overall, and after accounting for competing events (recurrence, death, and sterilizing surgeries).

RESULTS

There were 1,287 survivors in the chemotherapy group, 3,192 in the no chemotherapy group, and 34,147 women in the no cancer group, with a mean age of 33 years. Accounting for competing events, the overall 5-year LB incidence was lower in the chemotherapy group (3.9%) vs. the no chemotherapy group (6.4%). Adjusted relative risks vs. no chemotherapy and no cancer groups were 0.61 (95% confidence interval [CI] 0.42-0.82) and 0.70 (95% CI 0.51-0.93), respectively. The overall 5-year infertility incidence was similar in the chemotherapy group (21.8%) compared with the no chemotherapy group (20.7%). The adjusted relative risks vs. no chemotherapy and no cancer groups were 1.05 (95% CI 0.97-1.15) and 1.42 (95% CI 1.31-1.53), respectively.

CONCLUSIONS

Cancer survivors treated with platinum-based chemotherapy experienced modestly increased adverse fertility outcomes. The estimated effects of platinum-based chemotherapy were affected by competing events, suggesting the importance of this analytic approach for interpretations that ultimately inform clinical fertility preservation decisions.

A cross talk study on sitagliptin mediated reclamation on TGF β signalling, DPP 4, miR-29a and miR-24 expression in PCOS rats fed with high fat-high fructose diet

Polycystic Ovary Syndrome (PCOS) is a multifactorial reproductive, endocrine and metabolic disturbance which is very commonly observed in females of reproductive age group. The disease is still incurable however the use of synthetic drugs in combination with lifestyle is recommended. Accordingly, the present study was conducted to investigate the possible beneficial effects of sitagliptin on PCOS induced rats on control diet (CD)/high fat- high fructose diet (HFFD). PCOS was induced by giving testosterone propionate (TP) for 28 days to both the CD/HFFD rats and treated with STG i.p. for last 15 days. At the end of the experiment lipid profile, inflammatory markers, expression of NF-κB-p65, miR-24 and miR-29a, fibrotic and apoptotic proteins from ovary tissue were examined. Moreover, lipid accumulation and fibrosis of ovary tissue was further confirmed using Sudan III and Masson's trichrome stain. STG treated rats exerted a significant decrease in levels of cholesterol, TG, LDL-C, VLDL-C, IL-6 and TNF-α and increased HDL-C level, miR-24 and miR-29a expression. STG treated groups expressed significantly decreased expression of NF-κB-p65, TGF-β1, p-Smad 2 and p-Smad 3 followed by no significant changes in the expression of BAX, caspase-9, caspase-3 and Bcl-2 in all the PCOS induced groups. Among all the CD/ HFFD fed groups, rats on HFFD showed more devastating effect which suggests that diet plays a major role in genesis of PCOS. In conclusion, current results reflect the potential impact of STG against dyslipidaemia, inflammation and fibrosis in PCOS rats via regulating dyslipidaemia and fibrosis via DPP 4 mediated miR-29a expression.

Comprehensive Analysis of Damage Associated SNPs of Luteinizing Hormone and Its Receptor: A Computational Approach

PROBLEM

The luteinizing hormone (LH), produced by gonadal and nongonadal cells in the anterior pituitary gland play a critical role in human sexual development and reproduction. It is required for the induction of ovulation in females and sex steroid hormone production in both males and females. It is also an important player in early pregnancy events in oviducts and in absence of LH signalling, the uterus cannot initiate pregnancy. LH works through its receptor LHCGR. Therefore, it is quite important to figure out those mutations that have the potential to affect the structure and function of both LH and LHR.

MATERIALS AND METHODS

Various in silico tools were employed in the study for the data mining of SNPs and predicting their possible impact on the structure and function of the protein. ConSurf analysis predicted V454I and I161K are exposed residues in the 2D structure of protein and highly conserved in protein structure. PSIPRED and Swiss Modeller were employed to predict the 2D and 3D structure of mutated receptor protein. FT site server predicted both substitutions were involved in the ligand-binding site RESULTS: By present analysis, we have found that R59G in LHα, Q74R and T78N in LHβ and V454I and I161K in LHCGR are the most deleterious nsSNPs affecting the structure and function of the protein.

CONCLUSION

These SNPs are still uncharacterised; hence providing a baseline for validation of their association with the susceptibility of diseases and develop personalised therapeutics.

Research progress on the prevention and treatment of chemotherapy-induced ovarian damage

Chemotherapy is a main treatment option for malignant tumors, but it may cause various adverse effects, including dysfunction of female endocrine system and fertility. Chemotherapy-induced ovarian damage has been concerned with ovarian preservation but also the prevention and treatment of ovarian dysfunction. In this article, the mechanisms of ovarian injury caused by chemotherapy, including apoptosis of the follicle and supporting cells, follicle "burn out", ovarian stromal and microvascular damage; and influencing factors, including age at diagnosis, initial low pre-treatment anti-Müllerian hormone levels, toxicity, dose and regimen of chemotherapy drugs are reviewed based on the latest research results and clinical practice. The article also discusses measures and frontier therapies for the prevention and treatment of ovarian injury, including the application of gonadotropin releasing hormone agonists or antagonists, tyrosine kinase inhibitors, antioxidants, sphingosine-1-phosphate, ceramide-1-phosphate, mammalian target of rapamycin inhibitors, granulocyte-colony stimulating factor, stem cell therapy and artificial ovaries.

Zishen Yutai pills restore fertility in premature ovarian failure through regulating arachidonic acid metabolism and the ATK pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The Zishen Yutai pills (ZYP), a Chinese medicinal formulation derived from the Qing Dynasty prescription "Shou Tai pills", have been documented to exhibit beneficial effects in clinical observations treating premature ovarian failure (POF). However, the anti-POF effects and its comprehensive systemic mechanism have not yet been clarified.

AIM OF THE REVIEW

Therapeutic effects and systemic mechanism of ZYP in POF were evaluated.

MATERIALS AND METHODS

After pulverization, sieving, and stirring, ZYP was administered intragastrically to cisplatin-induced POF mice at a dose of 1.95 mg/kg/d for 14 days. The anti-POF effects of ZYP were investigated by assessing the number of ovarian follicles at different developmental stages, as well as measuring serum estradiol (E2) levels and ovarian-expressed anti-Müllerian hormone (AMH). Reproductive performance and offspring health were evaluated to predict fertility restoration. Furthermore, a combination of proteomic and metabolomic profiling was employed to elucidate the underlying molecular mechanism of ZYP in treating POF. Western blot (WB) analyses and real-time quantitative polymerase chain reaction (RT-qPCR) were conducted to explore the mechanisms through which ZYP exerted its anti-POF effects.

RESULTS

We have demonstrated that oral administration of ZYP reversed the reduction in follicles at different developmental stages and stimulated the expressions of serum E2 and ovarian-expressed AMH in a cisplatin-induced POF model. Additionally, ZYP ameliorated follicle apoptosis in ovaries affected by cisplatin-induced POF. Furthermore, treatment with ZYP restored the quantity and quality of oocytes, as well as enhanced fertility. Our results revealed 62 differentially expressed proteins (DEPs) through proteomic analyses and identified 26 differentially expressed metabolites (DEMs) through metabolomic analyses. Both DEPs and DEMs were highly enriched in the arachidonic acid (AA) metabolism pathway. ZYP treatment effectively upregulated the protein and mRNA expression of critical targets in AA metabolism and the AKT pathway, including CYP17α1, HSD3β1, LHR, STAR, and AKT, in cisplatin-induced POF mice.

CONCLUSIONS

These results indicated that ZYP exerted protective effects against POF and restored fertility from cisplatin-induced apoptosis. ZYP could be a satisfying alternative treating POF.

Germline cell de novo mutations and potential effects of inflammation on germline cell genome stability

Uncontrolled pathogenic genome mutations in germline cells might impair adult fertility, lead to birth defects or even affect the adaptability of a species. Understanding the sources of DNA damage, as well as the features of damage response in germline cells are the overarching tasks to reduce the mutations in germline cells. With the accumulation of human genome data and genetic reports, genome variants formed in germline cells are being extensively explored. However, the sources of DNA damage, the damage repair mechanisms, and the effects of DNA damage or mutations on the development of germline cells are still unclear. Besides exogenous triggers of DNA damage such as irradiation and genotoxic chemicals, endogenous exposure to inflammation may also contribute to the genome instability of germline cells. In this review, we summarized the features of de novo mutations and the specific DNA damage responses in germline cells and explored the possible roles of inflammation on the genome stability of germline cells.

Protective effect of Moringa oleifera leaf ethanolic extract against uranyl acetate-induced testicular dysfunction in rats

Uranyl acetate (UA) is used in civilian and military applications, predisposing it to wide dispersion in ecosystems. Using high-performance liquid chromatography, gas chromatography-mass spectrometry, and 2,2-Diphenyl-1-picrylhydrazyl scavenging radical analysis, we confirmed that Moringa oleifera leaf ethanolic extract (MLEE) is rich in biologically active phytochemicals. Thus, this study aims to investigate the possible defensive effect of MLEE against UA-induced testicular dysfunction. To achieve this, rats were divided randomly and evenly into three groups for 14 days. The control group received no treatment, while the UA group received a single intraperitoneal injection of UA at a dose of 5 mg/kg BW dissolved in saline on the 12th day of the experiment, followed by no treatment the following day. The MLEE + UA group received daily oral administration of MLEE (300 mg/kg BW) dissolved in distilled water before exposure to UA intoxication. The disruption observed in the pituitary-gonadal axis of UA-intoxicated rats was characterized by a significant decrease in luteinizing hormone, follicle-stimulating hormone, testosterone, and estradiol 17beta levels. Additionally, there was a notable increase in malondialdehyde and a decrease in catalase, superoxide dismutase, reduced glutathione, and nitric oxide, accompanied by an up-regulation in the immuno-expression of nuclear factor-kappa B, indicating a disturbance in the redox balance. The TUNEL assay confirmed a substantial rise in apoptotic cell numbers in the UA group. Testicular histopathological changes, excessive collagen deposition, and reduced glycogen content were evident following UA exposure. However, supplementation with MLEE effectively countered these mentioned abnormalities. MLEE is proposed to combat the toxicological molecular targets in the UA-affected testis by restoring the balance between oxidants and antioxidants while obstructing the apoptotic cascade. MLEE contains an abundance of redox-stabilizing and cytoprotective phytochemicals that have the potential to counteract the mechanistic pathways associated with UA exposure. These findings encourage further research into other plausible protective aspects of Moringa oleifera against the UA challenge.

Paeoniflorin Alleviates Cisplatin-Induced Diminished Ovarian Reserve by Restoring the Function of Ovarian Granulosa Cells via Activating FSHR/cAMP/PKA/CREB Signaling Pathway

Paeoniflorin (PAE) is the main active compound of Radix Paeoniae Rubra (a valuable traditional Chinese medicine and a dietary supplement) and exerts beneficial effects on female reproductive function. However, the actions of PAE on diminished ovarian reserve (DOR, a very common ovarian function disorder) are still unclear. Herein, our study investigated the effect and potential mechanism of PAE on DOR by using cisplatin-induced DOR mice and functional impairment of estradiol (E2) synthesis of ovarian granulosa-like KGN cells. Our data show that PAE improved the estrous cycle, ovarian index, and serum hormones levels, including E2, and the number of antral follicles and corpora lutea in DOR mice. Further mechanism results reveal that PAE promoted aromatase expression (the key rate-limiting enzyme for E2 synthesis) and upregulated the FSHR/cAMP/PKA/CREB signaling pathway in the ovaries. Subsequently, PAE improved the levels of E2 and aromatase and activated the FSHR/cAMP/PKA/CREB signaling pathway in KGN cells, while these improving actions were inhibited by the siRNA-FSHR and FSHR antagonist treatments. In sum, PAE restored the function of E2 synthesis in ovarian granulosa cells to improve DOR by activating the FSHR/cAMP/PKA/CREB signaling pathway, which exhibited a new clue for the development of effective therapeutic agents for the treatment of DOR.

Research progress on the premature ovarian failure caused by cisplatin therapy

Cisplatin is a common anticancer drug able to kill tumor cells, but it causes adverse reactions in the kidney, digestive tract, and other systems. The antitumor effects of cisplatin are mainly due to its ability to bind to the DNA in tumor cells to prevent replication, thereby reducing RNA and protein syntheses, leading to cell damage and death. Cisplatin has a wide range of applications; it can be used to treat cervical, thyroid, ovarian, and other cancers. Cisplatin has a beneficial therapeutic effect, but its therapeutic selectivity is poor. In addition to eliminating diseased target cells, cisplatin can damage normal cells; in women of reproductive age being treated for cancer, cisplatin can lead to ovarian function impairment, premature ovarian failure (POF), and/or infertility. Therefore, reducing the adverse effects of cisplatin on ovarian function is an important topic in clinical research. In this paper, we explore the research progress on the POF caused by cisplatin treatment.

Overactivation or Apoptosis: Which Mechanisms Affect Chemotherapy-Induced Ovarian Reserve Depletion?

Dormant primordial follicles (PMF), which constitute the ovarian reserve, are recruited continuously into the cohort of growing follicles in the ovary throughout female reproductive life. Gonadotoxic chemotherapy was shown to diminish the ovarian reserve pool, to destroy growing follicle population, and to cause premature ovarian insufficiency (POI). Three primary mechanisms have been proposed to account for this chemotherapy-induced PMF depletion: either indirectly via over-recruitment of PMF, by stromal damage, or through direct toxicity effects on PMF. Preventative pharmacological agents intervening in these ovotoxic mechanisms may be ideal candidates for fertility preservation (FP). This manuscript reviews the mechanisms that disrupt follicle dormancy causing depletion of the ovarian reserve. It describes the most widely studied experimental inhibitors that have been deployed in attempts to counteract these affects and prevent follicle depletion.

Optimisation of hormonal treatment to improve follicular development in one-day-old mice ovaries cultured under in vitro condition

CONTEXT

Base medium containing knock-out serum replacement (KSR) has been found to support formation and maintenance of follicles in one-day-old mice ovaries, but has not been shown to properly support activation and growth of primordial follicles.

AIMS

The present study was conducted to tailor the hormonal content of base medium containing KSR to enhance development of primordial follicles in neonatal ovaries.

METHODS

One-day-old mice ovaries were initially cultured with base medium for four days, and then, different hormonal treatments were added to the culture media and the culture was proceeded for four additional days until day eight. Ovaries were collected for histological and molecular assessments on days four and eight.

KEY RESULTS

In experiment I, the main and interactive effects of FSH and testosterone were investigated and FSH promoted activation of primordial follicles and development of primary and preantral follicles, and upregulated genes of phosphoinositide 3-kinase (Pi3k ), KIT ligand (Kitl ), growth differentiation factor 9 (Gdf9 ) and follicle stimulating hormone receptor (Fshr ) (P Bmp15 ), Connexin-43 (Cx43 ) and luteinising hormone and choriogonadotropin receptor (Lhcgr ) (P P Lhcgr (P P >0.05).

CONCLUSIONS

Supplementation of culture medium containing KSR with gonadotropins, particularly hMG, could improve follicular growth and expression of factors regulating follicular development.

IMPLICATIONS

This study was a step forward in formulating an optimal medium for development of follicles in cultured one-day-old mice ovaries.

CHEK2 signaling is the key regulator of oocyte survival after chemotherapy

Cancer treatments can damage the ovarian follicle reserve, leading to primary ovarian insufficiency and infertility among survivors. Checkpoint kinase 2 (CHEK2) deficiency prevents elimination of oocytes in primordial follicles in female mice exposed to radiation and preserves their ovarian function and fertility. Here, we demonstrate that CHEK2 also coordinates the elimination of oocytes after exposure to standard-of-care chemotherapy drugs. CHEK2 activates two downstream targets-TAp63 and p53-which direct oocyte elimination. CHEK2 knockout or pharmacological inhibition preserved ovarian follicle reserve after radiation and chemotherapy. However, the lack of specificity for CHEK2 among available inhibitors limits their potential for clinical development. These findings demonstrate that CHEK2 is a master regulator of the ovarian cellular response to damage caused by radiation and chemotherapy and warrant the development of selective inhibitors specific to CHEK2 as a potential avenue for ovario-protective treatments.

Inhibition of checkpoint kinase prevents human oocyte apoptosis induced by chemotherapy and allows enhanced tumour chemotherapeutic efficacy

STUDY QUESTION

Could inhibition of the checkpoint kinase (CHEK) pathway protect human oocytes and even enhance the anti-tumour effects, during chemotherapy?

SUMMARY ANSWER

CHEK inhibitors prevented apoptosis of human oocytes induced by chemotherapy and even enhanced the anti-tumour effects.

WHAT IS KNOWN ALREADY

CHEK inhibitors showed ovarian protective effects in mice during chemotherapy, while their role in human oocytes is unclear.

STUDY DESIGN, SIZE, DURATION

This experimental study evaluated the ovarian reserve of young patients (120 patients) with cancer, exposed or not exposed to taxane and platinum (TP)-combined chemotherapy. Single RNA-sequencing analysis of human primordial oocytes from 10 patients was performed to explore the mechanism of oocyte apoptosis induced by TP chemotherapy. The damaging effects of paclitaxel (PTX) and cisplatin on human oocytes were also evaluated by culturing human ovaries in vitro. A new mouse model that combines human ovarian xenotransplantation and patient-derived tumour xenografts was developed to explore adjuvant therapies for ovarian protection. The mice were randomly allocated to four groups (10 mice for each group): control, cisplatin, cisplatin + CK1 (CHEK1 inhibitor, SCH 900776), and cisplatin + CK2 (CHEK2 inhibitor, BML277).

PARTICIPANTS/MATERIALS, SETTING, METHODS

In the prospective cohort study, human ovarian follicles were counted and serum AMH levels were evaluated. RNA-sequencing analysis was conducted, and staining for follicular damage (phosphorylated H2AX histone; γH2AX), terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling (TUNEL) assays and assessments of apoptotic biomarkers (western blot and immunofluorescence) were conducted in human ovaries. After the treatments, histological analysis was performed on human ovarian samples to investigate follicular populations, and oocyte damage was measured by γH2AX staining, BAX staining, and TUNEL assays. At the same time, the tumours were evaluated for volume, weight, and apoptosis levels.

MAIN RESULTS AND THE ROLE OF CHANCE

Patients who received TP chemotherapy showed decreased ovarian reserves. Single RNA-sequencing analysis of human primordial oocytes indicated that TP chemotherapy induced apoptosis of human primordial oocytes by causing CHEK-mediated TAp63α phosphorylation. In vitro culture of human ovaries showed greater damaging effects on oocytes after cisplatin treatment compared with that after PTX treatment. Using the new animal model, CHEK1/2 inhibitors prevented the apoptosis of human oocytes induced by cisplatin and even enhanced its anti-tumour effects. This protective effect appeared to be mediated by inhibiting DNA damage via the CHEK-TAp63α pathway and by generation of anti-apoptotic signals in the oocytes.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

This was a preclinical study performed with human ovarian samples, and clinical research is required for validation.

WIDER IMPLICATIONS OF THE FINDINGS

These findings highlight the therapeutic potential of CHEK1/2 inhibitors as a complementary strategy for preserving fertility in female cancer patients.

STUDY FUNDING/COMPETING INTEREST(S)

This work was financially supported by the National Natural Science Foundation of China (nos. 82001514 and 81902669) and the Fundamental Research Funds for the Central Universities (2021yjsCXCY087). The authors declare no conflict of interest.

A minimal promoter region of Kit gene recapitulates mast cell differentiation in development, aging and inflammation

To follow mast cells (MCs) distribution during aging and inflammation, we characterized two transgenic mouse models in which the EGFP expression is controlled by 9kb or 12kb of Kit gene promoter, defined as p18 and p70, respectively. We detected EGFP-positive cells in the serosal surfaces of the peritoneum, pleuras and pericardium, mucosal cavities, and connective tissue of almost all organs including gonads of p70, but not of p18 mice. By FACS and immunofluorescence for FcεR1, Kit and β7-integrin, we found that these EGFP positive cells were MCs. In non-inflammatory conditions, a higher percentage of EGFP positive cells was found in juvenile with respect to adult serosal surfaces, but no differences between males and females at both developmental ages. We found, however, a striking difference in developing gonads, with low numbers of EGFP positive cells in foetal ovaries compared to age matched testes. Under inflammatory conditions caused by high fat diet (HFD), mice showed an increase in serosal EGFP positve cells. Altogether our results identify a regulatory region of the Kit gene, activated in MCs and that directing EGFP expression, can be employed to trace this immune cell type throughout the organism and in different animal conditions.

Ovulatory signal-triggered chromatin remodeling in ovarian granulosa cells by HDAC2 phosphorylation activation-mediated histone deacetylation

BACKGROUND

Epigenetic reprogramming is involved in luteinizing hormone (LH)-induced ovulation; however, the underlying mechanisms are largely unknown.

RESULTS

We here observed a rapid histone deacetylation process between two waves of active transcription mediated by the follicle-stimulating hormone (FSH) and the LH congener human chorionic gonadotropin (hCG), respectively. Analysis of the genome-wide H3K27Ac distribution in hCG-treated granulosa cells revealed that a rapid wave of genome-wide histone deacetylation remodels the chromatin, followed by the establishment of specific histone acetylation for ovulation. HDAC2 phosphorylation activation coincides with histone deacetylation in mouse preovulatory follicles. When HDAC2 was silenced or inhibited, histone acetylation was retained, leading to reduced gene transcription, retarded cumulus expansion, and ovulation defect. HDAC2 phosphorylation was associated with CK2α nuclear translocation, and inhibition of CK2α attenuated HDAC2 phosphorylation, retarded H3K27 deacetylation, and inactivated the ERK1/2 signaling cascade.

CONCLUSIONS

This study demonstrates that the ovulatory signal erases histone acetylation through activation of CK2α-mediated HDAC2 phosphorylation in granulosa cells, which is an essential prerequisite for subsequent successful ovulation.

The future of fertility preservation for women treated with chemotherapy

Cytotoxic chemotherapies have been a mainstay of cancer treatment, but are associated with numerous systemic adverse effects, including impacts to fertility and endocrine health. Irreversible ovarian damage and follicle depletion are side-effects of chemotherapy that can lead to infertility and premature menopause, both being major concerns of young cancer patients. Notably, many women will proceed with fertility preservation, but unfortunately existing strategies don't entirely solve the problem. Most significantly, oocyte and embryo freezing do not prevent cancer treatment-induced ovarian damage from occurring, which may result in the impairment of long-term hormone production. Unfortunately, loss of endogenous endocrine function is not fully restored by hormone replacement therapy. Additionally, while GnRH agonists are standard care for patients receiving alkylating chemotherapy to lessen the risk of premature menopause, their efficacy is incomplete. The lack of more broadly effective options stems, in part, from our poor understanding of how different treatments damage the ovary. Here, we summarise the impacts of two commonly utilised chemotherapies - cyclophosphamide and cisplatin - on ovarian function and fertility, and discuss the mechanisms underpinning this damage. Additionally, we critically analyse current research avenues in the development of novel fertility preservation strategies, with a focus on fertoprotective agents.

Ovarian Reserve Disorders, Can We Prevent Them? A Review

The ovarian reserve is finite and begins declining from its peak at mid-gestation until only residual follicles remain as women approach menopause. Reduced ovarian reserve, or its extreme form, premature ovarian insufficiency, stems from multiple factors, including developmental, genetic, environmental exposures, autoimmune disease, or medical/surgical treatment. In many cases, the cause remains unknown and resulting infertility is not ultimately addressed by assisted reproductive technologies. Deciphering the mechanisms that underlie disorders of ovarian reserve could improve the outcomes for patients struggling with infertility, but these disorders are diverse and can be categorized in multiple ways. In this review, we will explore the topic from a perspective that emphasizes the prevention or mitigation of ovarian damage. The most desirable mode of fertoprotection is primary prevention (intervening before ablative influence occurs), as identifying toxic influences and deciphering the mechanisms by which they exert their effect can reduce or eliminate exposure and damage. Secondary prevention in the form of screening is not recommended broadly. Nevertheless, in some instances where a known genetic background exists in discrete families, screening is advised. As part of prenatal care, screening panels include some genetic diseases that can lead to infertility or subfertility. In these patients, early diagnosis could enable fertility preservation or changes in family-building plans. Finally, Tertiary Prevention (managing disease post-diagnosis) is critical. Reduced ovarian reserve has a major influence on physiology beyond fertility, including delayed/absent puberty or premature menopause. In these instances, proper diagnosis and medical therapy can reduce adverse effects. Here, we elaborate on these modes of prevention as well as proposed mechanisms that underlie ovarian reserve disorders.

Hormone supply to the pituitary gland: A comprehensive investigation of female‑related tumors (Review)

The hypothalamus acts on the pituitary gland after signal integration, thus regulating various physiological functions of the body. The pituitary gland includes the adenohypophysis and neurohypophysis, which differ in structure and function. The hypothalamus-hypophysis axis controls the secretion of adenohypophyseal hormones through the pituitary portal vein system. Thyroid-stimulating hormone, adrenocorticotropic hormone, gonadotropin, growth hormone (GH), and prolactin (PRL) are secreted by the adenohypophysis and regulate the functions of the body in physiological and pathological conditions. The aim of this review was to summarize the functions of female-associated hormones (GH, PRL, luteinizing hormone, and follicle-stimulating hormone) in tumors. Their pathophysiology was described and the mechanisms underlying female hormone-related diseases were investigated.

Development of protective agents against ovarian injury caused by chemotherapeutic drugs

BACKGROUND

Chemotherapy is one of the causes of ovarian injury and infertility. Although assisted reproductive technology helps young female patients with cancer become pregnant, preventing chemotherapy-induced ovarian injury will often possess even more significant benefits.

OBJECTIVE

We aimed at demonstrating the hazardous effects and mechanisms of ovarian injury by chemotherapeutic agents, as well as demonstrating agents that protect the ovary from chemotherapy-induced injury.

RESULTS

Chemotherapeutic agents cause death or accelerate activation of follicles and damage to the blood vessels in the ovary, resulting in inflammation. These often require drug development to protect the ovaries from injury.

CONCLUSIONS

Our findings provide a basis for the development of drugs to protect the ovaries from injury. Although there are many preclinical studies on potential protective drugs, there is still an urgent need for a large number of clinical experiments to verify their potential use.

Long-term antimüllerian hormone patterns differ by cancer treatment exposures in young breast cancer survivors

OBJECTIVE

To compare antimüllerian hormone (AMH) patterns by cancer status and treatment exposures across 6 years after incident breast cancer using administrative data.

DESIGN

In a cross-sectional design, AMH levels in patients who developed incident breast cancer between ages 15-39 years during 2005-2019 were matched 1:10 to levels in females without cancer in the OptumLabs Data Warehouse. Modeled AMH patterns were compared among cyclophosphamide-based chemotherapy, non-cyclophosphamide-based chemotherapy, no chemotherapy, and no breast cancer groups.

SETTING

Commercially insured females in the United States.

PATIENT(S)

Females with and without breast cancer.

EXPOSURE(S)

Breast cancer, cyclophosphamide- and non-cyclophosphamide-based chemotherapy.

MAIN OUTCOME MEASURE(S)

AMH levels.

RESULT(S)

A total of 233 patients with breast cancer (mean age, 34 years; standard deviation, 3.7 years) contributed 278 AMH levels over a median of 2 years (range, 0-6.7 years) after diagnosis; 52% received cyclophosphamide-based chemotherapy, 17% received non-cyclophosphamide-based chemotherapy (80% platinum-based), and 31% received no chemotherapy. A total of 2,777 matched females without cancer contributed 2,780 AMH levels. The pattern of AMH levels differed among the 4 groups. Among females without cancer and breast cancer survivors who did not undergo chemotherapy, AMH declined linearly over time. In contrast, among those who received cyclophosphamide-based and noncyclophosphamide-based chemotherapy, a nonlinear pattern of AMH level of initial fall during chemotherapy, followed by an increase over 2-4 years, and then by a plateau over 1-2 years before a decline was observed.

CONCLUSION(S)

In breast cancer survivors, AMH levels from administrative data supported ovarian toxicity of non-cyclophosphamide-based chemotherapy in breast cancer and efficiently depicted the timing and duration of changes in ovarian reserve to reflect the residual reproductive lifespan.

Analysis of Secreted Proteins from Prepubertal Ovarian Tissues Exposed In Vitro to Cisplatin and LH

It is well known that secreted and exosomal proteins are associated with a broad range of physiological processes involving tissue homeostasis and differentiation. In the present paper, our purpose was to characterize the proteome of the culture medium in which the oocytes within the primordial/primary follicles underwent apoptosis induced by cisplatin (CIS) or were, for the most part, protected by LH against the drug. To this aim, prepubertal ovarian tissues were cultured under control and in the presence of CIS, LH, and CIS + LH. The culture media were harvested after 2, 12, and 24 h from chemotherapeutic drug treatment and analyzed by liquid chromatography-mass spectrometry (LC-MS). We found that apoptotic conditions generated by CIS in the cultured ovarian tissues and/or oocytes are reflected in distinct changes in the extracellular microenvironment in which they were cultured. These changes became evident mainly from 12 h onwards and were characterized by the inhibition or decreased release of a variety of compounds, such as the proteases Htra1 and Prss23, the antioxidants Prdx2 and Hbat1, the metabolic regulators Ldha and Pkm, and regulators of apoptotic pathways such as Tmsb4x. Altogether, these results confirm the biological relevance of the LH action on prepuberal ovaries and provide novel information about the proteins released by the ovarian tissues exposed to CIS and LH in the surrounding microenvironment. These data might represent a valuable resource for future studies aimed to clarify the effects and identify biomarkers of these compounds' action on the developing ovary.

The p53 network: cellular and systemic DNA damage responses in cancer and aging

The tumor protein TP53 gene, encoding the cellular tumor antigen p53, is the single most frequently mutated gene in human cancers. p53 plays a central role in responding to DNA damage and determines the outcome of the DNA damage checkpoint response by regulating cell cycle arrest and apoptosis. As a consequence of this function, dysfunctional p53 results in cells that, despite a damaged genome, continue to proliferate thus fueling malignant transformation. New insights have recently been gained into the complexity of the p53 regulation of the DNA damage response (DDR) and how it impacts a wide variety of cellular processes. In addition to cell-autonomous signaling mechanisms, non-cell-autonomous regulatory inputs influence p53 activity, which in turn can have systemic consequences on the organism. New inroads have also been made toward therapeutic targeting of p53 that for a long time has been anticipated.

Enhanced pro-apoptosis gene signature following the activation of TAp63α in oocytes upon γ irradiation

Specialized surveillance mechanisms are essential to maintain the genetic integrity of germ cells, which are not only the source of all somatic cells but also of the germ cells of the next generation. DNA damage and chromosomal aberrations are, therefore, not only detrimental for the individual but affect the entire species. In oocytes, the surveillance of the structural integrity of the DNA is maintained by the p53 family member TAp63α. The TAp63α protein is highly expressed in a closed and inactive state and gets activated to the open conformation upon the detection of DNA damage, in particular DNA double-strand breaks. To understand the cellular response to DNA damage that leads to the TAp63α triggered oocyte death we have investigated the RNA transcriptome of oocytes following irradiation at different time points. The analysis shows enhanced expression of pro-apoptotic and typical p53 target genes such as CDKn1a or Mdm2, concomitant with the activation of TAp63α. While DNA repair genes are not upregulated, inflammation-related genes become transcribed when apoptosis is initiated by activation of STAT transcription factors. Furthermore, comparison with the transcriptional profile of the ΔNp63α isoform from other studies shows only a minimal overlap, suggesting distinct regulatory programs of different p63 isoforms.

Whole Genome Transcriptomic Analysis of Ovary Granulosa Cells Revealed an Anti-Apoptosis Regulatory Gene DLGAP5 in Polycystic Ovary Syndrome

The mechanisms underlining pathogenesis of polycystic ovary syndrome (PCOS) remain largely unknown. Dysfunction of ovarian granulosa cells plays an important role. The present study performed the lncRNA and mRNA profiling by whole genome transcriptomic sequencing of ovary granulosa cells from women with PCOS and investigated the potential role of differentially expressed gens (DEGs) in the pathomechanism of PCOS. In total, 1,936 DEGs (30 upregulated and 1,906 downregulated mRNAs and lncRNAs) were identified in the ovary granulosa cells between control and PCOS group. Functional enrichment analysis showed that DEGs were mainly associated with cytokine-cytokine receptor interaction, neuroactive ligand-receptor interaction, and olfactory transduction. qRT-PCR validated the upregulation of DLGAP5 mRNA in ovary from PCOS group when compared to control group. Immunostaining and TUNEL assays showed that DLGAP5 protein level was increased while apoptosis was decreased in follicles of ovary in PCOS group. In vitro functional assays showed that DLGPA5 knockdown repressed viability and proliferation, but enhanced apoptosis and disrupted cell cycle in granulosa cells; while DLGAP5 overexpression had the opposite effects in granulosa cells. In conclusion, the study showed differentially expressed lncRNA and mRNA profile in the granulosa cells in ovaries of PCOS. Functional results demonstrated that DLGAP5 is a dysregulated candidate gene in the pathogenesis of PCOS, especially granulosa cell apoptosis and proliferation.

Female Oncofertility: Current Understandings, Therapeutic Approaches, Controversies, and Future Perspectives

Recent advances in early detection and oncological therapies have ameliorated the survival rate of young cancer patients. Yet, ovarian impairment induced by chemotherapy and radiotherapy is still a challenging issue. This review, based on clinical and lab-based studies, summarizes the evidence of gonadotoxicity of chemoradiotherapy, the recent approaches, ongoing controversies, and future perspectives of fertility preservation (FP) in female patients who have experienced chemo- or radio-therapy. Existing data indicate that chemotherapeutic agents induce DNA alterations and massive follicle activation via the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway. Meanwhile, the radiation causes ionizing damage, leading to germ cell loss. In addition to the well-established methods, numerous therapeutic approaches have been suggested, including minimizing the follicle loss in cryopreserved ovarian grafts after transplantation, in vitro activation or in vitro growing of follicles, artificial ovarian development, or fertoprotective adjuvant to prevent ovarian damage from chemotherapy. Some reports have revealed positive outcomes from these therapies, whereas others have demonstrated conflictions. Future perspectives are improving the live birth rate of FP, especially in patients with adverse ovarian reserve, eliminating the risk of malignancy reintroducing, and increasing society’s awareness of FP importance.

Human adipose-derived stromal cells transplantation prolongs reproductive lifespan on mouse models of mild and severe premature ovarian insufficiency

Background

Although recent studies have investigated the ability of Mesenchymal Stromal Cells (MSCs) to alleviate short-term ovarian damage in animal models of chemotherapy-induced Premature Ovarian Insufficiency (POI), no data are available on reproductive lifespan recovery, especially in a severe POI condition. For this reason, we investigated the potential of MSCs isolated from human adipose tissue (hASCs), since they are easy to harvest and abundant, in ameliorating the length and performance of reproductive life in both mild and severe chemotherapy-induced murine POI models.

Methods

Mild and severe POI models were established by intraperitoneally administering a light (12 mg/kg busulfan + 120 mg/kg cyclophosphamide) or heavy (30 mg/kg busulfan + 120 mg/kg cyclophosphamide) dose of chemotherapy, respectively, in CD1 mice. In both cases, a week later, 1 × 10⁶ hASCs were transplanted systemically through the tail vein. After four additional weeks, some females were sacrificed to collect ovaries for morphological evaluation. H&E staining was performed to assess stroma alteration and to count follicle numbers; immunofluorescence staining for αSMA was used to analyse vascularization. Of the remaining females, some were mated after superovulation to collect 2-cell embryos in order to evaluate their pre-implantation developmental capacity in vitro, while others were naturally mated to monitor litters and reproductive lifespan length. F1 litters’ weight, ovaries and reproductive lifespan were also analysed.

Results

hASC transplantation alleviated ovarian weight loss and size decrease and reduced alterations on ovarian stroma and vasculature, concurrently preventing the progressive follicle stockpile depletion caused by chemotherapy. These effects were associated with the preservation of the oocyte competence to develop into blastocyst in vitro and, more interestingly, with a significant decrease of chemotherapy-induced POI features, like shortness of reproductive lifespan, reduced number of litters and longer time to plug (the latter only presented in the severe POI model).

Conclusion

Human ASC transplantation was able to significantly reduce all the alterations induced by the chemotherapeutic treatment, while improving oocyte quality and prolonging reproductive functions, thus counteracting infertility. These results, strengthened by the use of an outbred model, support the potential applications of hASCs in women with POI, nowadays mainly induced by anticancer therapies.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02590-5.

Protective Mechanism of Luteinizing Hormone and Follicle-Stimulating Hormone Against Nicotine-Induced Damage of Mouse Early Folliculogenesis

Previous studies have shown that nicotine could impair the germ cell cyst breakdown and the primordial follicle assembly by autophagy. In this paper, we discovered that luteinizing hormone (LH) and follicle-stimulating hormone (FSH) could counteract the damage caused by nicotine of mouse germ cell cyst breakdown. The neonatal mice were separately intraperitoneally injected with nicotine, nicotine plus LH, nicotine plus FSH, and saline (control) for 4 days. Compared with the nicotine group, the quality of oocytes and the number of follicles were remarkably increased in the nicotine plus LH group or nicotine plus FSH group. LH and FSH could alleviate nicotine-induced oocyte autophagy by different pathways. LH reduced the nicotine-induced autophagy by restoring the phosphorylation level of adenosine 5′-monophosphate-activated protein kinase α-1, while FSH by downregulating the phosphorylation level of Forkhead box class O 1. In addition, in a subsequent study of 6-week mice in different treated groups, we found that LH and FSH supplementation significantly improved normal maturation rates, fertilization rates, and embryo’s developmental potential of oocytes in oocytes exposed to nicotine. Taken together, these results suggested that LH and FSH could counteract the damage caused by nicotine and finally ensure normal germ cell cyst breakdown and early embryo development.

PI3K/PTEN/AKT Signaling Pathways in Germ Cell Development and Their Involvement in Germ Cell Tumors and Ovarian Dysfunctions

Several studies indicate that the PI3K/PTEN/AKT signaling pathways are critical regulators of ovarian function including the formation of the germ cell precursors, termed primordial germ cells, and the follicular pool maintenance. This article reviews the current state of knowledge of the functional role of the PI3K/PTEN/AKT pathways during primordial germ cell development and the dynamics of the ovarian primordial follicle reserve and how dysregulation of these signaling pathways may contribute to the development of some types of germ cell tumors and ovarian dysfunctions.

Downregulation of miR-23b by transcription factor c-Myc alleviates ischemic brain injury by upregulating Nrf2

Ischemic brain injury (IBI) is a common acute cerebral vessel disease that occurs secondary to blockage in arteries, mainly characterized by insufficient blood supply to the brain. The transcription factor c-Myc in IBI continues to be implicated in numerous studies. This study was conducted with emphasis placed on the underlying mechanism of c-Myc in IBI. Clinical samples were collected from IBI patients. Middle cerebral artery occlusion (MCAO) was induced in mice by inserting a suture from the external carotid artery to the anterior cerebral artery through the internal carotid artery to mechanically block the blood supply at the origin of the middle cerebral artery, and cortical neurons from mice were exposed to oxygen glucose deprivation (OGD) conditions for IBI model in vitro construction. RT-qPCR was performed to determine microRNA-23b (miR-23b) expression. TUNEL staining and Western blot analysis was conducted to detect apoptosis. The regulatory relationship was analyzed by dual-luciferase reporter gene assay. After loss- and gain-of-function assays, triphenyltetrazolium chloride staining was carried out to detect the area of cerebral infarction, after which the spatial memory in mice was evaluated with Morris water maze test. As per our findings, miR-23b was upregulated in the serum of IBI patients and OGD-treated murine primary neurons. Silencing of miR-23b resulted in reduced OGD-induced neuronal apoptosis. miR-23b inversely targeted nuclear factor erythroid 2-related factor 2 (Nrf2) and c-Myc negatively regulated miR-23b expression. Overexpression of c-Myc and inhibition of miR-23b led to reduced neurological scores of infarction area, neuronal apoptosis, shortened platform arrival time and significantly increased the time spent on the platform quadrant and the times of crossing the platform in vivo. Collectively, downregulated miR-23b by c-Myc might alleviate IBI by upregulating Nrf2.

Protective effects of human umbilical cord mesenchymal stem cell-derived conditioned medium on ovarian damage

Chemotherapeutic agents are extensively used to treat malignancies. However, chemotherapy-induced ovarian damage and reduced fertility are severe side effects. Recently, stem cell transplantation has been reported to be an effective strategy for premature ovarian insufficiency (POI) treatment, but safety can still be an issue in stem cell-based therapy. Here, we show the protective effects of human umbilical cord mesenchymal stem cell-derived conditioned medium (hUCMSC-CM) on a cisplatin (Cs)-induced ovarian injury model. hUCMSC-CM can relieve Cs-induced depletion of follicles and preserve fertility. In addition, hUCMSC-CM can decrease apoptosis of oocytes and granulosa cells induced by Cs. RNA sequencing analysis reveals the differentially expressed genes of ovaries after Cs and hUCMSC-CM treatments, including genes involved in cell apoptosis. Furthermore, we show that the granulocyte colony-stimulating factor (G-CSF)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway plays an important role in protecting granulosa cells from Cs-induced apoptosis. Together, we confirm the protective effects of hUCMSC-CM on ovarian reserve and fertility in mice treated with Cs, highlighting the remarkable therapeutic effects of hUCMSC-CM.

Unraveling the mechanisms of chemotherapy-induced damage to human primordial follicle reserve: road to developing therapeutics for fertility preservation and reversing ovarian aging

Among the investigated mechanisms of chemotherapy-induced damage to human primordial follicle reserve are induction of DNA double-strand breaks (DSBs) and resultant apoptotic death, stromal-microvascular damage and follicle activation. Accumulating basic and translational evidence suggests that acute exposure to gonadotoxic chemotherapeutics, such as cyclophosphamide or doxorubicin, induces DNA DSBs and triggers apoptotic death of primordial follicle oocytes within 12-24 h, resulting in the massive loss of ovarian reserve. Evidence also indicates that chemotherapeutic agents can cause microvascular and stromal damage, induce hypoxia and indirectly affect ovarian reserve. While it is possible that the acute reduction of the primordial follicle reserve by massive apoptotic losses may result in delayed activation of some primordial follicles, this is unlikely to be a predominant mechanism of loss in humans. Here, we review these mechanisms of chemotherapy-induced ovarian reserve depletion and the potential reasons for the discrepancies among the studies. Based on the current literature, we propose an integrated hypothesis that explains both the acute and delayed chemotherapy-induced loss of primordial follicle reserve in the human ovary.

Benefits of Nigella sativa Extract Protecting Ovary Due to Cisplatin Chemotherapy

BACKGROUND: Cisplatin (CIS) is an important chemotherapy agent which is widely used for the treatment of many types of solid tumors, which can cause decreased ovarian function. Nigella sativa has been shown to have an anti-inflammatory and anti-oxidant activity that might protect the ovaries from damage due to CIS. AIM: This study aims to understand the benefits of N. sativa protecting the ovaries due to CIS chemotherapy. METHODS: Thirty-two female Rattus norvegicus aged 8 weeks weighing 160–200 g were divided into four groups: Negative control, Positive control, Treatment-1 (CIS 6 mg/KgBW and NS 500 mg/KgBW/day), and Treatment-2 (CIS 6 mg/KgBW and NS 1000 mg/kgBW/day) for 2 weeks. On the 14th day the rats were sacrificed, blood was drawn from the heart, followed by taking ovaries. RESULTS: There was lower mortality and morbidity in CIS + NS 1000 and CIS + NS 500 mg group (p = 0.01 and 0.001). The mean estradiol levels, follicle-stimulating hormone levels, and anti-mullerian hormone levels were not statistically significant among the four groups. The highest number of primary, secondary, tertiary follicles are seen at the CIS + NS 500 mg and CIS + NS 1000 mg groups (p = 0.05). The lowest number of atretic follicles is seen at the CIS + NS 1000 mg group, and the highest number of atretic follicles was in CIS only. CONCLUSION: There is a trend that N. sativa is beneficial in protecting the ovaries from damage caused by CIS.

The cyto-protective effects of LH on ovarian reserve and female fertility during exposure to gonadotoxic alkylating agents in an adult mouse model

STUDY QUESTION

Does LH protect mouse oocytes and female fertility from alkylating chemotherapy?

SUMMARY ANSWER

LH treatment before and during chemotherapy prevents detrimental effects on follicles and reproductive lifespan.

WHAT IS KNOWN ALREADY

Chemotherapies can damage the ovary, resulting in premature ovarian failure and reduced fertility in cancer survivors. LH was recently suggested to protect prepubertal mouse follicles from chemotoxic effects of cisplatin treatment.

STUDY DESIGN, SIZE, DURATION

This experimental study investigated LH effects on primordial follicles exposed to chemotherapy. Seven-week-old CD-1 female mice were randomly allocated to four experimental groups: Control (n = 13), chemotherapy (ChT, n = 15), ChT+LH-1x (n = 15), and ChT+LH-5x (n = 8). To induce primary ovarian insufficiency (POI), animals in the ChT and ChT+LH groups were intraperitoneally injected with 120 mg/kg of cyclophosphamide and 12 mg/kg of busulfan, while control mice received vehicle. For LH treatment, the ChT+LH-1x and ChT+LH-5x animals received a 1 or 5 IU LH dose, respectively, before chemotherapy, then a second LH injection administered with chemotherapy 24 h later. Then, two animals/group were euthanized at 12 and 24 h to investigate the early ovarian response to LH, while remaining mice were housed for 30 days to evaluate short- and long-term reproductive outcomes. The effects of LH and chemotherapy on growing-stage follicles were analyzed in a parallel experiment. Seven-week-old NOD-SCID female mice were allocated to control (n = 5), ChT (n = 5), and ChT+LH-1x (n = 6) groups. Animals were treated as described above, but maintained for 7 days before reproductive assessment.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In the first experiment, follicular damage (phosphorylated H2AX histone (γH2AX) staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay), apoptotic biomarkers (western blot), and DNA repair pathways (western blot and RT-qPCR) were assessed in ovaries collected at 12 and 24 h to determine early ovarian responses to LH. Thirty days after treatments, remaining mice were stimulated (10 IU of pregnant mare serum gonadotropin (PMSG) and 10 IU of hCG) and mated to collect ovaries, oocytes, and embryos. Histological analysis was performed on ovarian samples to investigate follicular populations and stromal status, and meiotic spindle and chromosome alignment was measured in oocytes by confocal microscopy. Long-term effects were monitored by assessing pregnancy rate and litter size during six consecutive breeding attempts. In the second experiment, mice were stimulated and mated 7 days after treatments and ovaries, oocytes, and embryos were collected. Follicular numbers, follicular protection (DNA damage and apoptosis by H2AX staining and TUNEL assay, respectively), and ovarian stroma were assessed. Oocyte quality was determined by confocal analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

LH treatment was sufficient to preserve ovarian reserve and follicular development, avoid atresia, and restore ovulation and meiotic spindle configuration in mature oocytes exposed at the primordial stage. LH improved the cumulative pregnancy rate and litter size in six consecutive breeding rounds, confirming the potential of LH treatment to preserve fertility. This protective effect appeared to be mediated by an enhanced early DNA repair response, via homologous recombination, and generation of anti-apoptotic signals in the ovary a few hours after injury with chemotherapy. This response ameliorated the chemotherapy-induced increase in DNA-damaged oocytes and apoptotic granulosa cells. LH treatment also protected growing follicles from chemotherapy. LH reversed the chemotherapy-induced depletion of primordial and primary follicular subpopulations, reduced oocyte DNA damage and granulosa cell apoptosis, restored mature oocyte cohort size, and improved meiotic spindle properties.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

This was a preliminary study performed with mouse ovarian samples. Therefore, preclinical research with human samples is required for validation.

WIDER IMPLICATIONS OF THE FINDINGS

The current study tested if LH could protect the adult mouse ovarian reserve and reproductive lifespan from alkylating chemotherapy. These findings highlight the therapeutic potential of LH as a complementary non-surgical strategy for preserving fertility in female cancer patients.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the Regional Valencian Ministry of Education (PROMETEO/2018/137), the Spanish Ministry of Science and Innovation (CP19/00141), and the Spanish Ministry of Education, Culture and Sports (FPU16/05264). The authors declare no conflict of interest.

Cisplatin decreases HOXA13 and alphaVBeta3 integrin levels in the uterus

OBJECTIVE

To examine the effects of cisplatin on uterine histology and implantation molecules and the possible protective role of recombinant Klotho administration on uterine histology and uterine receptivity in mice exposed to cisplatin.

MATERIALS AND METHODS

This study was conducted using thirty-two adult female mice assigned to four groups with 8 mice in each group. Saline was given to the 1st group, cisplatin to the 2nd group, recombinant mouse Klotho to the 3rd group and recombinant mouse Klotho plus cisplatin to the 4th group. Uterine tissues were examined for damage histologically and immunobiologically for the uterine receptivity markers HOXA13 and alphaVBeta3 integrin.

RESULTS

Apoptosis, degeneration, decrease in uterine thickness and uterine absence of gland scores were higher in the cisplatin group (3rd group) compared to the saline group (1st group) (cisplatin vs. saline p < 0.0001 for all parameters). In the recombinant Klotho plus cisplatin group (4th group), scores of apoptosis, degeneration, reduction in uterine thickness and uterine absence of gland were lower than the group receiving only cisplatin (cisplatin plus recombinant Klotho vs cisplatin, p = 0.006 for apoptosis; p = 0.017 for degeneration; p = 0.011 for the reduction in uterine thickness; p = 0.002 for the absence of gland). However, HOXA13 and alphaVBeta3 integrin staining levels were not different between the cisplatin group (group 3) and the cisplatin plus recombinant Klotho group (group 4) (p = 0.980 and p = 0.762, respectively.) CONCLUSION: Cisplatin has adverse effects on the uterus. Administration of recombinant Klotho was found to attenuate the cisplatin-induced damage but failed to preserve levels of the implantation molecules HOXA13 and alphaVbeta3. Further studies examining the effect of cisplatin toxicity using other implantation markers along with functional studies are needed.

Evaluation of mitochondria in mouse oocytes following cisplatin exposure

BACKGROUND

Cisplatin is a platinum-based chemotherapeutic that damages genomic DNA leading to cell death. It also damages mitochondrial DNA and induces high levels of mitochondrial reactive oxygen species (mtROS), further sensitising cells to apoptosis. Notably, immature oocytes are particularly vulnerable to cisplatin treatment, a common side effect of which is depletion of the primordial follicle reserve, leading to infertility and early menopause. Cisplatin is known to damage the DNA of oocytes, but the possibility that cisplatin also compromises oocyte survival and quality by damaging mitochondria, has not been investigated. To begin to address this question, neonatal mice were treated with saline or cisplatin (2 mg/kg or 4 mg/kg) and the short and long-term impacts on mitochondria in oocytes were characterised.

RESULTS

At 6 and 24 h after treatment, mitochondrial localisation, mass and ATP content in immature oocytes were similar between groups. However, TMRM staining intensity, a marker of mitochondrial membrane potential, was decreased in immature oocytes from cisplatin treated mice compared to saline treated controls, consistent with the induction of apoptosis. When mice were super ovulated 5 weeks after exposure, the number of mature oocytes harvested from cisplatin treated mice was significantly lower than controls. Mitochondrial localisation, mass, membrane potential and ATP levels showed no differences between groups.

CONCLUSIONS

These findings suggest that mitochondrial dysfunction may contribute to the depletion of the ovarian reserve caused by cisplatin, but long-term impacts on mitochondria may be minimal as those immature oocytes that survive cisplatin treatment develop into mature oocytes with normal mitochondrial parameters.

Experimental study for the establishment of a chemotherapy-induced ovarian insufficiency model in rats by using cyclophosphamide combined with busulfan

With an improvement in the survival rate of cancer patients, chemotherapy-induced premature ovarian insufficiency (POI) is increasingly affecting the quality of life of female patients. Currently, there are many relevant studies using mice as an animal model. However, a large coefficient of variation for weight in mice is not appropriate for endocrine-related studies, compared with rats; therefore, it is necessary to identify an appropriate experimental model in rats. In this study, cyclophosphamide combined with busulfan was used to establish an animal model. We compared several common modeling methods using chemotherapeutic drugs, cisplatin, cyclophosphamide, and 4-vinylcyclohexene diepoxide (VCD), and we found that the combination of cyclophosphamide and busulfan was more effective in establishing a POI model in rats with few side effects by analyzing general physical conditions, pathological tissue sections of heart, liver, lung, spleen, kidney, uterus, and ovary, serum hormone levels, and follicle counts; thus, providing a more reliable model basis for subsequent studies.

Melatonin provides protection against cisplatin-induced ovarian damage and loss of fertility in mice

RESEARCH QUESTION

Can melatonin provide non-invasive ovarian protection against damage caused by cis-diamminedichloroplatinum (cisplatin) and preserve fertility in female cancer patients? And if so, what is the possible mechanism?

DESIGN

Athymic BALB/c nude tumour-bearing female mice were used to demonstrate whether melatonin affects the antineoplastic effect when co-administrated with cisplatin. Sexually mature and newborn C57BL/6 female mice were used to evaluate the potential effects of melatonin on the ovarian follicle pool, pregnancy rate and litter number in cisplatin-treated mice. The ovaries underwent immunohistochemical, TdT (terminal deoxynucleotidyl transferase)-mediated dUTP nick-end labelling (TUNEL) and gene array analysis to explore the underlying mechanism. In addition, granulosa cells were isolated to investigate the potential protective mechanism of melatonin.

RESULTS

Melatonin not only enhanced the anti-cancer effect of cisplatin in tumour-bearing nude mice, but also reduced ovarian toxicity and preserved long-term fertility in cisplatin-treated C57BL/6 female mice. When co-administrated, melatonin was able to reduce the DNA damage and toxic effects on lipid peroxidation in the ovaries caused by cisplatin. Specifically, melatonin was able to largely restore lipid peroxidation in granulosa cells and thus prevent ovarian follicles from being depleted.

CONCLUSIONS

Melatonin has the potential to be used as a chemotherapeutic adjuvant to simultaneously improve the outcome of anti-cancer treatment and preserve ovarian function during cisplatin chemotherapy. Notably, its properties of DNA protection and antioxidant effects on follicles may benefit female cancer survivors and prevent premature ovarian failure as well as fertility loss caused by chemotherapy.

The effects of recombinant klotho in cisplatin-induced ovarian failure in mice

AIM

To investigate whether recombinant klotho given concomitantly with cisplatin is effective in preventing cisplatin-induced ovarian damage.

METHODS

Thirty-two adult female mice were divided into four groups. Saline was given to the first group, cisplatin to the second group, recombinant mouse klotho to the third group, and recombinant mouse klotho + cisplatin to the fourth group. The removed ovarian tissues were examined and groups were compared histologically and immunohistochemical examination for antimullerian hormone (AMH), superoxide dismutase (SOD) and catalase expression were done. Glutathione peroxidase (GPx) and glutathione reductase (GR) activities were measured by ELISA.

RESULTS

Ovarian tissue weight, primary and secondary follicle counts were higher in cisplatin + recombinant klotho group compared to cisplatin group in our study (respectively p < 0.0001, p < 0.0001, and p = 0.010). Injury scores (stromal congestion, edema and infiltration, follicular degeneration scores and edema in corpus luteum scores) were similar between cisplatin and cisplatin + recombinant klotho groups (all p > 0.05). AMH staining intensities were similar between cisplatin and cisplatin + recombinant klotho groups (p = 0.925). There was no difference between the groups in terms of SOD, GPx, and GR (p > 0.05).

CONCLUSIONS

The recombinant klotho administered before cisplatin could partially protect the ovarian tissue from cisplatin-induced ovarian damage considering that there was no difference in histologic injury score parameters, AMH staining intensity and oxidative stress markers between cisplatin and cisplatin plus klotho groups except that klotho preserved follicules to some extent. The antioxidant mechanism of action of klotho may not be the primary protection mechanism in cisplatin induced ovarian injury.

Di (2-ethylhexyl) phthalate impairs primordial follicle assembly by increasing PDE3A expression in oocytes

It is known that Di (2-ethylhexyl) phthalate (DEHP) may impact mammalian reproduction and that in females one target of the drug's action is follicle assembly. Here we revisited the phthalate's action on the ovary and from bioinformatics analyses of the transcriptome performed on newborn mouse ovaries exposed in vitro to DEHP, up-regulation of PDE3A, as one of the most important alterations caused by DEHP on early folliculogenesis, was identified. We obtained some evidence suggesting that the decrease of cAMP level in oocytes and the parallel decrease of PKA expression, consequent on the PDE3A increase, were a major cause of the reduction of follicle assembly in the DEHP-exposed ovaries. In fact, Pde3a RNAi on cultured ovaries reducing cAMP and PKA decrease counteracted the primordial follicle assembly impairment caused by the compound. Moreover, RNAi normalized the level of Kit, Nobox, Figla mRNA and GDF9, BMP15, CX37, γH2AX proteins in oocytes, and KitL transcripts in granulosa cells as well as their proliferation rate altered by DEHP exposure. Taken together, these results identify PDE3A as a new critical target of the deleterious effects of DEHP on early oogenesis in mammals and highlight cAMP-dependent pathways as major regulators of oocyte and granulosa cell activities crucial for follicle assembly. Moreover, we suggest that the level of intracellular cAMP in the oocytes may be an important determinant for their capability to repair DNA lesions caused by DNA damaging compounds including DEHP.

The p63 C-terminus is essential for murine oocyte integrity

The transcription factor p63 mediates distinct cellular responses, primarily regulating epithelial and oocyte biology. In addition to the two amino terminal isoforms, TAp63 and ΔNp63, the 3’-end of p63 mRNA undergoes tissue-specific alternative splicing that leads to several isoforms, including p63α, p63β and p63γ. To investigate in vivo how the different isoforms fulfil distinct functions at the cellular and developmental levels, we developed a mouse model replacing the p63α with p63β by deletion of exon 13 in the Trp63 gene. Here, we report that whereas in two organs physiologically expressing p63α, such as thymus and skin, no abnormalities are detected, total infertility is evident in heterozygous female mice. A sharp reduction in the number of primary oocytes during the first week after birth occurs as a consequence of the enhanced expression of the pro-apoptotic transcriptional targets Puma and Noxa by the tetrameric, constitutively active, TAp63β isoform. Hence, these mice show a condition of ovary dysfunction, resembling human primary ovary insufficiency. Our results show that the p63 C-terminus is essential in TAp63α-expressing primary oocytes to control cell death in vivo, expanding the current understanding of human primary ovarian insufficiency.

The transcription factor p63 mediates different cellular responses affecting epithelial and oocyte biology. Here, the authors generate a mouse model (HET Δ13p63 mice) expressing the p63β isoform and show this affects ovary development, phenocopying a human syndrome, primary ovary insufficiency.

DNA Damaged Induced Cell Death in Oocytes

The production of haploid gametes through meiosis is central to the principle of sexual reproduction. The genetic diversity is further enhanced by exchange of genetic material between homologous chromosomes by the crossover mechanism. This mechanism not only requires correct pairing of homologous chromosomes but also efficient repair of the induced DNA double-strand breaks. Oocytes have evolved a unique quality control system that eliminates cells if chromosomes do not correctly align or if DNA repair is not possible. Central to this monitoring system that is conserved from nematodes and fruit fly to humans is the p53 protein family, and in vertebrates in particular p63. In mammals, oocytes are stored for a long time in the prophase of meiosis I which, in humans, can last more than 50 years. During the entire time of this arrest phase, the DNA damage checkpoint remains active. The treatment of female cancer patients with DNA damaging irradiation or chemotherapeutics activates this checkpoint and results in elimination of the oocyte pool causing premature menopause and infertility. Here, we review the molecular mechanisms of this quality control system and discuss potential therapeutic intervention for the preservation of the oocyte pool during chemotherapy.

Chemoprotective effects of plasma derived from mice of different ages and genders on ovarian failure after cyclophosphamide treatment

Background

Premature ovarian failure is one of the major side effects of chemotherapy drugs. Blood plasma contains several factors that might lead to the repair of different tissues.

Objective

The chemoprotective effects of plasma derived from mice with different ages and genders were assessed on ovarian tissue in cyclophosphamide-treated mice.

Methods

Forty-two adult female mice were divided into six groups as follows: (A) control; (B) 0.9% sodium chloride as vehicle; (C) cyclophosphamide; (D) cyclophosphamide + young male blood plasma; (E) cyclophosphamide + old male blood plasma; (F) cyclophosphamide + young female blood plasma. Ovarian failure was induced by injecting cyclophosphamide. On the 1st day, three groups received simultaneous injections of 150 μL intraperitoneal and 70 μL intravenous plasma derived from mice of different ages and genders. Each plasma type (150 μL) was then injected intraperitoneally every other 3 days for 19 days. On day 21, the dissected ovaries were stained for stereological analysis. Also, estrogen and progesterone levels were measured.

Results

Cyclophosphamide had damaging effects on ovarian parameters and led to reduced hormone levels in comparison with the control group. However, treating with young female and, old male blood plasma, to a lesser degree, showed beneficial effects on the number of primordial follicles, pre-antral follicles, and granulosa cells. Also, these two treatments had protective effects on the volume of ovarian parameters as well as estrogen and progesterone levels in comparison with the cyclophosphamide group (P < 0.05).

Conclusion

Plasma derived from mice of different ages and genders can ameliorate premature ovarian failure against the adverse effects of cyclophosphamide.

Membrane Estrogen Receptor (GPER) and Follicle-Stimulating Hormone Receptor (FSHR) Heteromeric Complexes Promote Human Ovarian Follicle Survival

Classically, follicle-stimulating hormone receptor (FSHR)-driven cAMP-mediated signaling boosts human ovarian follicle growth and oocyte maturation. However, contradicting in vitro data suggest a different view on physiological significance of FSHR-mediated cAMP signaling. We found that the G-protein-coupled estrogen receptor (GPER) heteromerizes with FSHR, reprogramming cAMP/death signals into proliferative stimuli fundamental for sustaining oocyte survival. In human granulosa cells, survival signals are missing at high FSHR:GPER ratio, which negatively impacts follicle maturation and strongly correlates with preferential Gαs protein/cAMP-pathway coupling and FSH responsiveness of patients undergoing controlled ovarian stimulation. In contrast, FSHR/GPER heteromers triggered anti-apoptotic/proliferative FSH signaling delivered via the Gβγ dimer, whereas impairment of heteromer formation or GPER knockdown enhanced the FSH-dependent cell death and steroidogenesis. Therefore, our findings indicate how oocyte maturation depends on the capability of GPER to shape FSHR selective signals, indicating hormone receptor heteromers may be a marker of cell proliferation.

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G-protein-coupled estrogen receptor (GPER) interacts with FSH receptor (FSHR)

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FSHR/GPER heteromers reprogram FSH-induced death signals to proliferative stimuli

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Anti-apoptotic signaling of heteromers is via a GPER-Gαs inhibitory complex and Gβγ

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Heteromer formation impacts follicle maturation and FSH responses of IVF patients

Advances in the Treatment and Prevention of Chemotherapy-Induced Ovarian Toxicity

Due to improvements in chemotherapeutic agents, cancer treatment efficacy and cancer patient survival rates have greatly improved, but unfortunately gonadal damage remains a major complication. Gonadotoxic chemotherapy, including alkylating agents during reproductive age, can lead to iatrogenic premature ovarian insufficiency (POI), and loss of fertility. In recent years, the demand for fertility preservation has increased dramatically among female cancer patients. Currently, embryo and oocyte cryopreservation are the only established options for fertility preservation in women. However, there is growing evidence for other experimental techniques including ovarian tissue cryopreservation, oocyte in vitro maturation, artificial ovaries, stem cell technologies, and ovarian suppression. To prevent fertility loss in women with cancer, individualized fertility preservation options including established and experimental techniques that take into consideration the patient's age, marital status, chemotherapy regimen, and the possibility of treatment delay should be provided. In addition, effective multidisciplinary oncofertility strategies that involve a highly skilled and experienced oncofertility team consisting of medical oncologists, gynecologists, reproductive biologists, surgical oncologists, patient care coordinators, and research scientists are necessary to provide cancer patients with high-quality care.

Impact of first-line cancer treatment on the follicle quality in cryopreserved ovarian samples from girls and young women

STUDY QUESTION

Does first-line chemotherapy affect the quality of ovarian pre-antral follicles and stromal tissue in a population of young patients?

SUMMARY ANSWER

Exposure to first-line chemotherapy significantly impacts follicle viability, size of residual intact follicles, steroid secretion in culture and quality of the stromal compartment.

WHAT IS KNOWN ALREADY

First-line chemotherapy is considered to have a low gonadotoxic potential, and as such, does not represent an indication for fertility preservation. Studies investigating the effects of chemotherapy on the quality of ovarian tissue stored for fertility preservation in young patients are limited and the results sometimes contradictory.

STUDY DESIGN, SIZE, DURATION

We conducted a retrospective cohort study including young patients referred to three centers (Helsinki, Oslo and Tampere) to perform ovarian tissue cryopreservation for fertility preservation between 2003 and 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 43 patients (age 1-24 years) were included in the study. A total of 25 were exposed to first-line chemotherapy before cryopreservation, whereas 18 patients were not. Density and size of follicles divided by developmental stages, prevalence of atretic follicles, health of the stromal compartment and functionality of the tissue in culture were evaluated and related to age and chemotherapy exposure. Activation of dormant follicles and DNA damage were also assessed.

MAIN RESULTS AND THE ROLE OF CHANCE

Patients exposed to first-line chemotherapy showed a significantly higher density of atretic primordial and intermediary follicles than untreated patients. The intact primordial and intermediary follicles were significantly smaller in size in patients exposed to chemotherapy. Production of steroids in culture was also significantly impaired and a higher content of collagen and DNA damage was observed in the stromal compartment of treated patients. Collectively, these observations may indicate reduced quality and developmental capacity of follicles as a consequence of first-line chemotherapy exposure. Neither increased activation of dormant follicles nor elevated levels of DNA damage in oocyte nuclei were found in patients exposed to chemotherapy.

LIMITATIONS, REASONS FOR CAUTION

The two groups were not homogeneous in terms of age and the patients were exposed to different treatments, which did not allow us to distinguish the effect of specific agents. The limited material availability did not allow us to perform all the analyses on the entire set of patients.

WIDER IMPLICATION OF THE FINDINGS

This study provides for the first time a comprehensive analysis of the effects of first-line chemotherapy on the health, density and functionality of follicles categorized according to the developmental stage in patients under 24 years of age. When exposed to these treatments, patients were considered at low/medium risk of infertility. Our data suggest a profound impact of these relatively safe therapies on ovarian health and encourages further exploration of this effect in follow-up studies in order to optimize fertility preservation for young cancer patients.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the Swedish Childhood Cancer Foundation, the Finnish Cancer Society, the Finnish Pediatric Research Foundation, the Väre Foundation for Pediatric Cancer Research, The Swedish Research Council, the Stockholm County Council (ALF project) and Karolinska Institutet. The authors have no conflict of interest to declare.