Imatinib mesylate does not counteract ovarian tissue fibrosis in postnatal rat ovary

Chemotherapy may result in ovarian atrophy, a depletion of the primordial follicle pool, diminished ovarian weight, cortical and stromal fibrosis. Imatinib mesylate is an anticancer agent that inhibits competitively several receptor tyrosine kinases (RTKs). RTKs play important roles in cell metabolism, proliferation, and apoptosis. In clinic, imatinib mesylate is also known as an anti-fibrotic medicine. In the present study, the impact of imatinib on the ovarian tissue was investigated by assessing ovarian tissue fibrosis in postnatal rat administered with or without imatinib for three days. Fibrosis in the ovarian tissue was determined by histology (Picrosirius and Masson's trichrome staining) and the protein expression of vimentin and alpha-smooth muscle actin (alpha-SMA). Furthermore, mRNA expression of Forkhead box transcription factor O1 and O3 (FOXO1 and FOXO3), which are markers of cell proliferation was quantified. A short-term exposure to imatinib showed to increase tissue fibrosis in ovaries. This was observed by Masson's trichrome staining. Exposure to imatinib led also to a down-regulation of vimentin protein expression and up-regulation mRNA expression of FOXO3. This may indicate a role of FOXO3 in ovarian tissue fibrosis in postnatal rat ovaries.Peer reviewe

Effect of Previous Alkylating Agent Exposure on Follicle Numbers in Cryopreserved Prepubertal and Young Adult Ovarian Tissue after Long-Term Xenografting

Simple Summary Cryopreservation of ovarian tissue is a promising technique for fertility preservation in cancer patients at increased risk for subfertility. The International Guideline Harmonization Group recommends ovarian tissue cryopreservation for children and young adults before therapy with cumulative doses of alkylating agent at or above 6000-8000 mg/m(2). A therapy that poses a high risk of subfertility is rarely the first-line therapy and many of the patients have already undergone several regimens of chemotherapy. The aim of our study was to assess the effects of chemotherapy exposures on the quality of cryopreserved ovarian tissue. We confirmed the harmful effects of alkylating agents on xenografted ovarian tissue and suggest that cumulative doses which are not regarded as an indication for fertility preservation in children and young adult may decrease the quality of cryopreserved follicles. Purpose and methods: To elucidate whether previous cancer treatment affects graft recovery and follicle numbers, morphology, and development in grafts, cryopreserved ovarian biopsies obtained from 18 cancer patients aged 1-24 years with and without exposure to chemotherapy were xenografted as 1 mm(3) fragments to immunodeficient mice for 22 weeks with exogenous stimulation. Results: Graft recovery showed no association with chemotherapy exposure, pubertal stage, or leukemia contamination. Total follicle number per recovered graft varied between 0 and 1031 in the chemotherapy-exposed and between 0 and 502 in the non-chemotherapy-exposed group. Atretic follicles formed the largest proportion of the follicle pool in chemotherapy-exposed grafts. Increased atresia correlated with exposure to alkylating agents (mean +/- SD 8866.2 +/- 9316.3 mg/m(2)) but not with anthracyclines, pubertal stage, or leukemia contamination. Conclusion: The observation confirms the harmful effects of alkylating agents on ovarian tissue. Therapy at the median cumulative dose of 8866 mg/m(2) leads to the decreased quality of cryopreserved ovarian follicles in children and young adults.Peer reviewe

Effect of Previous Alkylating Agent Exposure on Follicle Numbers in Cryopreserved Prepubertal and Young Adult Ovarian Tissue after Long-Term Xenografting

Simple Summary Cryopreservation of ovarian tissue is a promising technique for fertility preservation in cancer patients at increased risk for subfertility. The International Guideline Harmonization Group recommends ovarian tissue cryopreservation for children and young adults before therapy with cumulative doses of alkylating agent at or above 6000-8000 mg/m(2). A therapy that poses a high risk of subfertility is rarely the first-line therapy and many of the patients have already undergone several regimens of chemotherapy. The aim of our study was to assess the effects of chemotherapy exposures on the quality of cryopreserved ovarian tissue. We confirmed the harmful effects of alkylating agents on xenografted ovarian tissue and suggest that cumulative doses which are not regarded as an indication for fertility preservation in children and young adult may decrease the quality of cryopreserved follicles. AbstractPurpose and methods: To elucidate whether previous cancer treatment affects graft recovery and follicle numbers, morphology, and development in grafts, cryopreserved ovarian biopsies obtained from 18 cancer patients aged 1-24 years with and without exposure to chemotherapy were xenografted as 1 mm(3) fragments to immunodeficient mice for 22 weeks with exogenous stimulation. Results: Graft recovery showed no association with chemotherapy exposure, pubertal stage, or leukemia contamination. Total follicle number per recovered graft varied between 0 and 1031 in the chemotherapy-exposed and between 0 and 502 in the non-chemotherapy-exposed group. Atretic follicles formed the largest proportion of the follicle pool in chemotherapy-exposed grafts. Increased atresia correlated with exposure to alkylating agents (mean +/- SD 8866.2 +/- 9316.3 mg/m(2)) but not with anthracyclines, pubertal stage, or leukemia contamination. Conclusion: The observation confirms the harmful effects of alkylating agents on ovarian tissue. Therapy at the median cumulative dose of 8866 mg/m(2) leads to the decreased quality of cryopreserved ovarian follicles in children and young adults.</p

Effect of Previous Chemotherapy on the Quality of Cryopreserved Human Ovarian Tissue In Vitro

Background Cryopreservation of ovarian tissue has been widely accepted as an option for fertility preservation among cancer patients. Some patients are exposed to chemotherapy prior to ovarian tissue cryopreservation. Consequently, assessment of the developmental capacity of human ovarian tissue after chemotherapy is of primary importance. Materials In order to study the impact of previous chemotherapy on in vitro development and viability of ovarian follicles, quality control samples from 34 female cancer patients at median age of 15 years (range 1-35), cryopreserved for fertility preservation before (n = 14) or after (n = 20) initiation of chemotherapy, were thawed and cultured for 7 days. The morphology and developmental stages of ovarian follicles were studied by light microscopy before and after culture. Possible associations between follicular densities, age and exposure to alkylating agents, expressed as cyclophosphamide equivalent dose (CED) were tested. Results Exposure to chemotherapy significantly impaired the survival and development of ovarian follicles in culture. After seven days, significantly higher densities of intermediary, primary and secondary follicles and lower densities of atretic follicles was detected in the samples collected before chemotherapy. Increasing dose of alkylating agents was identified by multivariate linear regression analysis as an independent predictor of a higher density of atretic follicles, whereas increasing age of the patient predicted a better outcome with less follicle atresia and a higher density of maturing follicles. Conclusion This study provides quantitative in vitro evidence of the impact of chemotherapy on developmental capacity of cryopreserved human ovarian tissue. The results indicate that fertility preservation should be carried out, if possible, before initiation of alkylating agents in order to guarantee better in vitro survival of ovarian follicles. In addition, ovarian samples from younger girls show lower viability and fewer developing follicles in culture.Peer reviewe

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.Peer reviewe

Trolox enhances follicular survival after ovarian tissue autograft in squirrel monkey (Saimiri collinsi)

The aim of this study was to evaluate ovarian tissue pre-treatment with 50 µM Trolox followed by heterotopic transplantation in squirrel monkeys (Saimiri collinsi) and to assess tissue functionality via immunohistochemical analysis of the stroma and ovarian follicles. Five healthy and sexually mature squirrel monkey (Saimiri collinsi) females were used. Heterotopic autografting of fresh ovarian tissue with or without previous exposure to the antioxidant Trolox was performed and grafts were recovered for analysis 7 days later. Tissue vascularisation was confirmed by both macroscopic inspection and cluster of differentiation 31 (CD31) staining. Trolox prevented massive follicular activation and kept the percentages of morphologically normal follicles higher than in untreated grafts. Expression of anti-Müllerian hormone in developing follicles was observed only in controls and Trolox-treated grafts. Also, immunostaining for growth differentiation factor-9 was positive only in primordial follicles from controls and from Trolox-treated grafts. Although Trolox improved follicular quality and avoided apoptosis in stromal cells, ovarian tissue fibrosis was increased in Trolox-treated grafts, mainly due to an increase in collagen Type I synthesis

Effect of Previous Alkylating Agent Exposure on Follicle Numbers in Cryopreserved Prepubertal and Young Adult Ovarian Tissue after Long-Term Xenografting

Purpose and methods: To elucidate whether previous cancer treatment affects graft recovery and follicle numbers, morphology, and development in grafts, cryopreserved ovarian biopsies obtained from 18 cancer patients aged 1–24 years with and without exposure to chemotherapy were xenografted as 1 mm3 fragments to immunodeficient mice for 22 weeks with exogenous stimulation. Results: Graft recovery showed no association with chemotherapy exposure, pubertal stage, or leukemia contamination. Total follicle number per recovered graft varied between 0 and 1031 in the chemotherapy-exposed and between 0 and 502 in the non-chemotherapy-exposed group. Atretic follicles formed the largest proportion of the follicle pool in chemotherapy-exposed grafts. Increased atresia correlated with exposure to alkylating agents (mean ± SD 8866.2 ± 9316.3 mg/m2) but not with anthracyclines, pubertal stage, or leukemia contamination. Conclusion: The observation confirms the harmful effects of alkylating agents on ovarian tissue. Therapy at the median cumulative dose of 8866 mg/m2 leads to the decreased quality of cryopreserved ovarian follicles in children and young adults

Developmental effects of imatinib mesylate on follicle assembly and early activation of primordial follicle pool in postnatal rat ovary

Imatinib mesylate is an anti-cancer agent that competitively inhibits several receptor tyrosine kinases (RTKs). RTKs play important roles in the regulation of primordial follicle formation, the recruitment of primordial follicles into the pool of growing follicles and maturation of the follicles. In the present study, we investigated the effects of the tyrosine kinase inhibitor imatinib on primordial follicle assembly and early folliculogenesis in postnatal rats. Female Sprague-Dawley rats were treated with either imatinib (150mg/kg) or placebo (water) on postnatal days 2-4. Bilateral ovariectomy was performed on postnatal day 2 and 5. Histology, immunohistochemistry, and mRNA analysis were performed. Imatinib treatment was associated with increased density of the multi-oocyte follicles (P<0.01), oogonia (p<0.01) and germline clusters (P<0.05), decreased activation of primordial follicles, increased expression of c-Kit and AMH, and decreased protein expression of Kit-ligand and GDF9 when compared to age-matched controls. In conclusion, imatinib affects folliculogenesis in postnatal rat ovaries by delaying the cluster breakdown, follicular assembly and early activation of the primordial follicle pool