Looking beyond the ovary for oncofertility care in women: uterine injury as a potential target for fertility-preserving treatments

Female reproductive health in pediatric, adolescent, and young adult cancer survivors

An estimated 500,000 cancer survivors of reproductive age in the United States will live to experience the long-term consequences of cancer treatment. Therefore, a focused aspect of cancer care has appropriately shifted to include quality of life in survivorship. Infertility is a late effect of therapy that affects 12% of female survivors of childhood cancer receiving any cancer treatment in large cohort studies and results in a 40% decreased likelihood of pregnancy in young adults of ages 18-39 years. Nonfertility gynecologic late effects such as hypoestrogenism, radiation-induced uterine and vaginal injury, genital graft-versus-host disease after hematopoietic stem cell transplant, and sexual dysfunction also significantly affect quality of life in survivorship but are underdiagnosed and require consideration. Several articles in the special edition "Reproductive Health in Adolescent and Young Adult Cancer Survivorship" address infertility, genital graft-versus-host disease, and psychosexual functioning in survivorship. This review article focuses on other adverse gynecologic outcomes of cancer therapies including hypogonadism and hormone replacement therapy, radiation-induced uterovaginal injury, vaccination and contraception, breast and cervical cancer screening, and pregnancy considerations in survivorship.

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.

Resveratrol alleviates doxorubicin-induced damage in mice ovary

While oocytes and embryos cryopreservation can favor some patients with cancer-induced infertility to achieve pregnancy, the development of effective therapeutic strategies to preserve ovarian function during chemotherapy would be a significant advantage. The aim of the present study is to analyze whether Resveratrol treatment (Res) can preserve ovarian function from doxorubicin (Doxo)-induced gonadotoxicity using a mice model of premature ovarian failure. Res (7 and 15 mg/kg) increased the percentage of primary and antral follicles whilst decreasing the percentage of atretic follicles compared to Doxo alone. Res preserved the number of primordial follicles compared with those in the Doxo group but they did not change from those in the control group. Res treatment increased the number of AMH positive follicles compared to Doxo alone. Res increased proliferation index in follicular cells and reduced the DNA damage and apoptosis in preantral and early antral follicles compared to Doxo alone. Additionally, Doxo administration caused a severe endothelial damage and affected microvasculature stability in the ovary. However, Res was able to increase the recruitment of pericytes and smooth muscle cells in the Doxo-treated group. We also found that Res increased the expression of VEGF compared to Doxo alone. By H&E staining, Doxo-treated mice demonstrated endometrial alterations compared to controls, affecting both epithelial and stromal compartments. Nonetheless, Res restored the architecture of uterine tissue. Moreover, we also showed that Res administration is able to maintain antioxidant defenses through the increase of SOD expression in the Doxo-induced POF model. In conclusion, Res administration prior to and during Doxo treatment might serve as a noninvasive and low-cost protocol to preserve ovarian function in female cancer survivors.

Protective effects of L-carnitine on X irradiation-induced uterus injury via antioxidant and anti-inflammatory pathways

PURPOSE

Ionizing radiation causes oxidative stress induced tissue damage as well as a decline in reproduction incidence. The purpose of our study was to evaluate the effects of L-carnitine on radiation-induced uterine injury.

MATERIALS AND METHODS

Thirty Wistar albino rats were classified into five groups. Physiological saline was administered intraperitoneally to the control group. A single dose of 8.3 Gy whole body X-irradiation was applied to the radiation-1 and radiation-2 groups. These groups were sacrificed on the 6th hour and 4th day, respectively, after irradiation. Radiation-1 + L-carnitine and radiation-2 + L-carnitine groups received a daily dose of 200 mg/kg L-carnitine in addition to the same dose of irradiation. L-carnitine was also applied one day before and four days after irradiation.

RESULTS

L-carnitine therapy partially blocks the depletion of the deep glands and radiation-induced flattening of the glandular epithelium and endometrial surface. Proinflammatory cytokines such as IL-1β, IL-6 and TNF-α were found to be significantly expressed in the uterus tissue of irradiated mice. In the radiation groups, NFκB and PARP-1 expressions in uterine tissue was significantly increased compared to L-carnitine treated and the control groups. It was observed that the oxidative stress index increased in the radiation groups, but decreased in the L-carnitine applied groups.

CONCLUSIONS

Our findings showed that L-carnitine has a positive effect on radiation-induced uterine damage. L-carnitine may be a potential safe radio protective agent during radiotherapy for pelvic cancer provided the tumor is not protected from radiation damage to the same extent as the normal tissue is. However, prospective clinical trial studies are necessary to understand its efficacy.

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.

Cyclophosphamide Exposure Causes Long-Term Detrimental Effect of Oocytes Developmental Competence Through Affecting the Epigenetic Modification and Maternal Factors' Transcription During Oocyte Growth

Cyclophosphamide (CTX) is widely used in various cancer therapies and in immunosuppression, and patients can still have babies after CTX chemotherapy. CTX directly causes primordial follicle loss with overactivation and DNA damage-induced apoptosis. Previous studies have shown that maternal exposure to CTX before conception increases the incidence of birth abnormalities and alters the methylation of genes in the oocytes of offspring. Mice were treated with a single dose of CTX (100 mg/kg) at post-natal day 21 and sacrificed 47 days later when primordial follicles surviving chemotherapy developed to the antral stage. Acute DNA damage and acceleration of the activation of primordial follicles after CTX treatment were repaired within several days, but the remaining follicle numbers remarkably decrease. Although partial surviving primordial follicle were developed to mature oocyte, oocyte quality hemostasis was impaired exhibiting aberrant meiosis progression, abnormal spindle and aneuploidy, mitochondrial dysfunction and increased endoplasmic reticulum stress. Thereafter, embryo development competency significantly decreased with fewer blastocyst formation after CTX exposure. CTX treatment resulted in alteration of DNA methylations and histone modifications in fully grown GV oocytes. Single-cell RNA-seq revealed CTX treatment suppressed multiple maternal genes’ transcription including many methyltransferases and maternal factor YAP1, which probably accounts for low quality of CTX-repaired oocyte. In vitro addition of lysophosphatidic acid (LPA) to embryo culture media to promote YAP1 nuclear localization improved CTX-repaired embryo developmental competence. This study provides evidence for the consistent toxic effect of CTX exposure during follicle development, and provide a new mechanism and new insights into future clinical interventions for fertility preservation.