| 1. |
- Bongaerts, Eva, et al.
(author)
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Ambient black carbon particles in human ovarian tissue and follicular fluid
- 2023
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In: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 179
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Journal article (peer-reviewed)abstract
- Evidence indicates a link between exposure to ambient air pollution and decreased female fertility. The ability of air pollution particles to reach human ovarian tissue and follicles containing the oocytes in various maturation stages has not been studied before. Particulate translocation might be an essential step in explaining reproductive toxicity and assessing associated risks. Here, we analysed the presence of ambient black carbon particles in (i) follicular fluid samples collected during ovum pick-up from 20 women who underwent assisted reproductive technology treatment and (ii) adult human ovarian tissue from 5 individuals. Follicular fluid and ovarian tissue samples were screened for the presence of black carbon particles from ambient air pollution using white light generation by carbonaceous particles under femtosecond pulsed laser illumination. We detected black carbon particles in all follicular fluid (n = 20) and ovarian tissue (n = 5) samples. Black carbon particles from ambient air pollution can reach the ovaries and follicular fluid, directly exposing the ovarian reserve and maturing oocytes. Considering the known link between air pollution and decreased fertility, the impact of such exposure on oocyte quality, ovarian ageing and fertility needs to be clarified urgently.
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| 2. |
- Li, Tianyi, et al.
(author)
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Persistent organic pollutants dysregulate energy homeostasis in human ovaries in vitro
- 2024
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In: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 187
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Journal article (peer-reviewed)abstract
- Exposure to persistent organic pollutants (POPs), such as dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs), has historically been linked to population collapses in wildlife. Despite international regulations, these legacy chemicals are still currently detected in women of reproductive age, and their levels correlate with reduced ovarian reserve, longer time -to -pregnancy, and higher risk of infertility. However, the specific modes of action underlying these associations remain unclear. Here, we examined the effects of five commonly occurring POPs - hexachlorobenzene (HCB), p,p '-dichlorodiphenyldichloroethylene (DDE), 2,3,3 ' ,4,4 ' ,5-hexachlorobiphenyl (PCB156), 2,2 ' ,3,4,4 ' ,5,5 ' -heptachlorobiphenyl (PCB180), perfluorooctane sulfonate (PFOS) - and their mixture on human ovaries in vitro . We exposed human ovarian cancer cell lines COV434, KGN, and PA1 as well as primary ovarian cells for 24 h, and ovarian tissue containing unilaminar follicles for 6 days. RNA -sequencing of samples exposed to concentrations covering epidemiologically relevant levels revealed significant gene expression changes related to central energy metabolism in the exposed cells, indicating glycolysis, oxidative phosphorylation, fatty acid metabolism, and reactive oxygen species as potential shared targets of POP exposures in ovarian cells. Alpha-enolase ( ENO1 ), lactate dehydrogenase A ( LDHA ), cytochrome C oxidase subunit 4I1 ( COX4I1 ), ATP synthase F1 subunit alpha ( ATP5A ), and glutathione peroxidase 4 ( GPX4 ) were validated as targets through qPCR in additional cell culture experiments in KGN. In ovarian tissue cultures, we observed significant effects of exposure on follicle growth and atresia as well as protein expression. All POP exposures, except PCB180, decreased unilaminar follicle proportion and increased follicle atresia. Immunostaining confirmed altered expression of LDHA, ATP5A, and GPX4 in the exposed tissues. Moreover, POP exposures modified ATP production in KGN and tissue culture. In conclusion, our results demonstrate the disruption of cellular energy metabolism as a novel mode of action underlying POP -mediated interference of follicle growth in human ovaries.
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| 3. |
- Papaikonomou, Kiriaki
(author)
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The effect of a progesterone receptor modulator on the endometrium and breast in premenopausal women
- 2021
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Doctoral thesis (other academic/artistic)abstract
- Background: The levonorgestrel intrauterine system, LNG-IUS 52 mg, is a highly effective and costeffective contraceptive, entailing minimal patient effort. Irregular bleeding patterns are common during the first months of use and constitutes one of the main reasons for discontinuation. Up to date, no standard treatment approach has been proven to resolve this problem. Mifepristone is a synthetic steroid hormone, acting mainly as an inhibitor of the progesterone receptor (PR) thereby preventing the effect of progesterone. Administration of mifepristone has been proven beneficial in numerous fields in reproductive medicine and exerts various effects depending on the dosage and stage of the menstrual cycle at treatment. Administration of low daily doses of mifepristone results in anovulation and endometrial suppression with subsequent amenorrhea. Continuous treatment with PRMs cause endometrial alterations previously thought to be similar to unopposed estrogen exposure, given the PR antagonistic effects of PRMs. These alterations are today recognized as progesterone receptor modulator associated changes (PAEC). They are considered to be benign and dissolves with the cessation of treatment. The molecular alterations resulting in their development are still unknown. The mechanism of action of steroidal hormones on breast tissue remains largely unidentified. Epidemiological studies show a positive correlation between number of menstrual cycle exposure and hormone therapy to the risk of breast cancer. While this increased risk has been believed to be mainly caused by estrogen, a growing body of literature suggest progesterone and progestins to play a central role. PRMs can be used as a tool to study the effects of progesterone and holds potential to prevent breast epithelial cell proliferation. Aim: The overall aim of this thesis is to explore the effects of the PRM mifepristone on the endometrium and on human breast tissue in premenopausal women. The specific objectives were to assess whether inducing amenorrhea with mifepristone, prior to placement of the LNG-IUS, could reduce the bleeding irregularities during the first months of use. Another objective was to evaluate the endometrial morphology after continuous treatment with mifepristone following insertion of the LNG-IUS, without prior endometrial shedding. Furthermore, we sought to explore how mifepristone alters the transcriptomic landscape in human beast in vivo and the epigenetic alterations observed in the breast tissue following PRM treatment. Materials, methods and results: Study I was a prospective, randomized, placebo controlled, double-blind trial including healthy women with regular menstrual cycles opting for the LNG-IUS 52 mg for contraceptive purposes. Fifty-eight women were randomized whereof 29 to the mifepristone and 29 to the comparator group. Study participants received mifepristone, 50 mg every other day or a comparator. The pretreatment period with mifepristone was 2 months, followed by the LNG-IUS insertion. Women kept bleeding diaries as per instruction for the pretreatment period and until 6 months after placement of the device. After removing drop outs and exclusions, 19 women in the mifepristone and 19 in the comparator arm contributed to the final analysis. Bleeding diary data were analyzed as rates of bleeding and spotting days (B/S%) per treatment cycle. The results showed a significant reduction of B/S% during the pretreatment period in the mifepristone arm compared to placebo. Following insertion of the device, no statistical difference could be seen between the two groups. Women in Study II originated from Study I. Endometrial biopsies were retrieved at baseline, prior to the pretreatment period with mifepristone or the comparator. A second biopsy was retrieved at 3 months following LNG-IUS placement, with the IUS in situ. Nine paired biopsies from the mifepristone and 8 from the comparator group, contributed to the final analysis. The specimens were analyzed by an expert pathologist who was blinded to the treatment. All baseline biopsies where benign. The second biopsies were all benign and showed, as expected, changes due to progestin effect on the endometrium. There was no presence of PAEC. Participants in Study III originated from Study I. Core needle breast biopsies were collected at baseline and after 2 months treatment with mifepristone or the comparator. Paired biopsies from 16 women in the mifepristone group contributed to the analysis. The changes on mRNA expression level at baseline compared to after mifepristone treatment were screened using RNA sequencing. Functional annotation and pathway enrichment analysis of the differentially expressed genes (DEGs) revealed genes mainly involved in extracellular matrix (ECM) remodeling. In Study IV, patient cohorts and databases were used to generate and validate a breast tissue specific epigenetic index. That index was subsequently used to assess breast tissue samples from three clinical trials, including Study I. Based on the results from this specific epigenetic index, PRM treatment could exhibit favorable results in the mammary gland from healthy women as well as women with increased risk for developing breast cancer. Conclusion: The applied mifepristone treatment regimen could not demonstrate any significant improvement in bleeding disturbances following placement of the LNG-IUS compared to placebo. Continuous treatment with mifepristone and subsequent LNG-IUS insertion without prior endometrial shedding, could represent a safe alternative regarding PAEC endometrial safety. Transcriptomic alterations in the breast after treatment with mifepristone revealed pathways mainly involved in ECM remodeling. Furthermore, epigenetic and genetic alterations in the breast following PRM treatment seem promising and suggestive of further investigations regarding the potential beneficial effects of these compounds in the prevention of breast cancer.
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| 4. |
- Tarvainen, Ilari, et al.
(author)
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Identification of phthalate mixture exposure targets in the human and mouse ovary in vitro
- 2023
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In: Reproductive Toxicology. - : Elsevier. - 0890-6238 .- 1873-1708. ; 119
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Journal article (peer-reviewed)abstract
- Chemical health risk assessment is based on single chemicals, but humans and wildlife are exposed to extensive mixtures of industrial substances and pharmaceuticals. Such exposures are life-long and correlate with multiple morbidities, including infertility. How combinatorial effects of chemicals should be handled in hazard charac-terization and risk assessment are open questions. Further, test systems are missing for several relevant health outcomes including reproductive health and fertility in women. Here, our aim was to screen multiple ovarian cell models for phthalate induced effects to identify biomarkers of exposure. We used an epidemiological cohort study to define different phthalate mixtures for in vitro testing. The mixtures were then tested in five cell models representing ovarian granulosa or stromal cells, namely COV434, KGN, primary human granulosa cells, primary mouse granulosa cells, and primary human ovarian stromal cells. Exposures at epidemiologically relevant levels did not markedly elicit cytotoxicity or affect steroidogenesis in short 24-hour exposure. However, significant effects on gene expression were identified by RNA-sequencing. Altogether, the exposures changed the expression of 124 genes on the average (9-479 genes per exposure) in human cell models, without obvious concentration or mixture-dependent effects on gene numbers. The mixtures stimulated distinct changes in different cell models. Despite differences, our analyses suggest commonalities in responses towards phthalates, which forms a starting point for follow-up studies on identification and validation of candidate biomarkers that could be developed to novel assays for regulatory testing or even into clinical tests.
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