Dose addition in mixtures of compounds with dissimilar endocrine modes of action in in vitro receptor activation assays and the zebrafish sexual development test

BACKGROUND

Human exposure to pesticides is being associated with feminisation for which a decrease of the anogenital distance (AGD) is a sensitive endpoint. Dose addition for the cumulative risk assessment of pesticides in food is considered sufficiently conservative for combinations of compounds with both similar and dissimilar modes of action (MoA).

OBJECTIVE

The present study was designed to test the dose addition hypothesis in a binary mixture of endocrine active compounds with a dissimilar mode of action for the endpoint feminisation.

METHODS

Compounds were selected from a list of chemicals of which exposure is related to a decrease of the AGD in rats and completed with reference compounds. These chemicals were characterised using specific in vitro transcriptional activation (TA) assays for estrogenic and androgenic properties, leading to a final selection of dienestrol as an ER-agonist and flutamide, linuron, and deltamethrin as AR-antagonists. These compounds were then tested in an in vivo model, i.e. in zebrafish (Danio rerio), using sex ratio in the population as an endpoint in order to confirm their feminising effect and MoA. Ultimately, the fish model was used to test a binary mixture of flutamide and dienestrol.

RESULTS

Statistical analysis of the binary mixture of flutamide and dienestrol in the fish sexual development tests (FSDT) with zebrafish supported dose addition.

Pillbug: A Toolbox for Feminisation

Wolbachia-induced feminisation is an extended phenotype that has been observed in only three models: isopods, butterflies and leafhoppers. Even among these, the process of feminisation differs markedly, especially since sexual differentiation is coordinated body-wide by a hormone in isopods, whereas in insects it is a chromosomally determined process and enforced cell by cell. For isopods, Armadillidium vulgare has contributed substantially to an understanding of Wolbachia-mediated feminisation, because a wide array of know-how and methods has been tailored to this model. Here, we describe establishment and maintenance of Wolbachia-infected laboratory lineages from animals collected in the field, the grafting of an androgenic gland to demonstrate the mode of action of Wolbachia (i.e. the disruption of the Androgenic Hormone pathway), and transinfection of naïve adults with Wolbachia. Finally, we describe selection of a ZZ genetic background in lineages created from transinfected WZ females, which is necessary to benefit from a property intrinsic to the naturally infected lineages: In a ZZ background, the vertical transmission rate of Wolbachia directly equates to the female ratio in the progeny. These protocols provide the essential framework for investigating molecular aspects of Wolbachia-induced feminisation.

Effects of dietary supplementation of estradiol-17β during fry stage on growth, physiological and immune parameters and gonadal gene expression in adult snakeskin gourami

In snakeskin gourami (Trichopodus pectoralis), females are generally larger than males, and estradiol-17β (E2)-sex reversal to produce female monosex has gained interest in this species. In this study, we aimed to investigate the effects of E2-induced sex reversal on growth, physiological and immune parameters, and gonadal gene expression in adult snakeskin gourami. Fry (7 days posthatching) were divided into different experimental groups based on the dose of E2: control (no E2 (0 mg kg-1) supplementation), E2-100 (100 mg kg-1), E2-200 (200 mg kg-1), and E2-300 (300 mg kg-1), fed with the E2 doses for 90 d and cultured for 11 months (adult stage). The findings revealed that E2 supplementation produced 88.89-100% of female population. After 11 months of culture, the effects of sexual dimorphism on the growth performance of the E2-100 group were not significant compared to that on the growth performance of the control male and female groups; however, it improved significantly in the E2-200 and E2-300 groups (P < 0.05). E2 elevated the CP and fat contents in body in E2-200 and E2-300 groups (P < 0.05) compared to that in the control group. No sex differences in blood metabolites, haematological values, or immune parameters were identified. Nevertheless, E2-200 and E2-300 groups showed increased blood glucose, triglyceride, haemoglobin, and total immunoglobulin (P < 0.05) compared to control male fish. In addition, all concentrations of E2 increased alternative complement 50 (P < 0.05). Several genes, including bHLH, cyp19a1, daz, deadend, esrb, esrrg, gnrhr, gpa, gsg1l, hsd17β, mospd1, nanos2, p53, piwi2, rerg, rps6ka, tgfb, and vgr, showed differential expression between testis and ovary in control female and E2-treated groups. The expression patterns of the genes were similar in the ovary of the control female and E2-200-treated fish. In conclusion, the findings demonstrate that a feminisation duration of 7-97 days and two doses of E2 at 200 or 300 mg kg-1 successfully produced all-female stocks in snakeskin gourami. Furthermore, the findings showed that E2-treated females were maintained throughout adulthood and exhibited several superior characteristics to male fish. Together with the information generated on differentially expressed sex-related genes, these findings could enable the culturing of faster-growing sex to increase productivity and contribute to the development of intensive snakeskin gourami farming.

Facial feminisation surgery in NHS Scotland

Facial feminisation surgery (FFS) is integral to the management of transgender adult females. Literature detailing the conduct and outcomes of FFS is lacking. The aim of this project was to review surgical practices in NHS Scotland. We identified Gender Identity Clinics throughout Scotland. These clinics were then contacted to discuss which services were available regarding FFS and to whom they refer patients. Retrospective review of electronic case notes between June 2014 and June 2019 was carried out and data was recorded on patient demographics, procedures employed, surgical complications, and postoperative outcome. FFS was carried out in two centres. Sixty patients received FFS during the study period, in 160 separate surgical procedures. Patients were all transitioning from natal biological male to female gender, with an average age of 36 years. The most common procedure was rhinoplasty (n = 36). Surgical complications occurred in eight procedures, and negative outcomes were recorded in 12/88 operating sessions. Increasing demand for surgery was noted throughout the study period. These results suggest that a wide variety of procedures are used, and that FFS is well accepted with relatively few surgical complications and negative outcomes. In depth understanding of patient's perceptions and views of their experiences, alongside objective measures, are essential to determine the impacts of FFS.

How do applicants, students and physicians think about the feminisation of medicine? - a questionnaire-survey

BACKGROUND

The implications of the feminisation of medicine, which is characterised by a growing proportion of female doctors, is a topic currently being debated worldwide. To date, however, there has been no systematic survey of the viewpoint of present and future doctors on this subject. The aim of the present study is to determine how future and present doctors view this trend in terms of its relevance to the medical profession and its present impacts.

METHODS

Of a total sample of 3813 people, 181 applicants for the winter term 2014, 590 medical students and 225 doctors of the UMG participated in this cross-sectional electronic questionnaire. The answers were analysed by means of the statistics program IBM SPSS Statistics 22. Open answers were qualitatively evaluated and categorised using the "Basiswissengeleitete offene Kategorienfindung" (Werner Früh) and coded for statistical analysis.

RESULTS

The majority of our participants favoured a balanced gender-ratio among doctors: 77% of applicants, 68% of students and 61% of doctors rated this as important or very important. The results from the student and applicant groups differed concerning female gender. When answering in the role of a patient, the doctor's gender was found to be more relevant than when the participants were answering in the role of the doctor. The majority of the respondents opined that feminisation had had an impact on their workplace: particular factors included part-time work, work-related organisation and the diversity of the medical profession. Commentaries were mostly categorised as negative.

CONCLUSIONS

The feminisation of medicine was viewed largely critically by the participants of this study. The respondents evaluated gender as being relevant for the medical profession and favoured a diverse workforce; however, the significance of one's own gender in medical practice was underrated in comparison, implying a need for more awareness of the effect of a doctor's gender on the patient-doctor-relationship. The mainly negative comments concerning the impact of feminisiation on work organisation, work satisfaction and patient care show the need for further research and action to adapt current medical work practices to the changing demographics in order to improve work satisfaction and quality of care.

Environmental chemicals active as human antiandrogens do not activate a stickleback androgen receptor but enhance a feminising effect of oestrogen in roach

Sexual disruption is reported in wild fish populations living in freshwaters receiving discharges of wastewater treatment works (WwTW) effluents and is associated primarily with the feminisation of males by exposure to oestrogenic chemicals. Antiandrogens could also contribute to the feminisation of male fish, but there are far less data supporting this hypothesis and almost nothing is known for the effects of oestrogens in combination with antiandrogens in fish. We conducted a series of in vivo exposures in two fish species to investigate the potency on reproductive-relevant endpoints of the antiandrogenic antimicrobials triclosan (TCS), chlorophene (CP) and dichlorophene (DCP) and the resin, abietic acid (AbA), all found widely in WwTW effluents. We also undertook exposures with a mixture of antiandrogens and a mixture of antiandrogens in combination with the oestrogen 17α-ethinyloestradiol (EE2). In stickleback (Gasterosteus aculeatus), DCP showed a tendency to reduce spiggin induction in females androgenised by dihydrotestosterone (DHT), but these findings were not conclusive. In roach (Rutilus rutilus), exposures to DCP (178 days), or a mixture of TCS, CP and AbA (185 days), or to the model antiandrogen flutamide (FL, 178 days) had no effect on gonadal sex ratio or on the development of the reproductive ducts. Exposure to EE2 (1.5ng/L, 185 days) induced feminisation of the ducts in 17% of the males and in the mixture of antiandrogens (TCS, CP, AbA) in combination with EE2, almost all (96%) of the males had a feminised reproductive ducts. In stickleback androgen receptor (ARα and ARβ) transactivation assays, the model antiandrogens, FL and procymidone inhibited 11-ketotestosterone (11-KT) induced receptor activation, but none of the human antiandrogens, TCS, CP, DCP and AbA had an effect. These data indicate that antimicrobial antiandrogens in combination can contribute to the feminisation process in exposed males, but they do not appear to act through the androgen receptor in fish.

Microsporidian parasites feminise hosts without paramyxean co-infection: support for convergent evolution of parasitic feminisation

Feminisation of amphipod crustaceans is associated with the presence of at least three microsporidian parasites and one paramyxean parasite, suggesting that the ability to feminise has evolved multiple times in parasites of amphipods. Co-infection by a paramyxean with one of the putative microsporidian feminisers, Dictyocoela duebenum, has inspired the alternative hypothesis that all feminisation of amphipods is caused by paramyxea and that all microsporidian associations with feminisation are due to co-infection with paramyxea (Short et al., 2012). In a population of the amphipod Gammarus duebeni, breeding experiments demonstrate that the microsporidia D. duebenum and Nosema granulosis are associated with feminisation in the absence of paramyxea. Co-infection of the two microsporidia is no more frequent than expected at random and each parasite is associated with feminisation in the absence of the other. These findings support the original hypothesis that the ability to feminise amphipods has evolved in microsporidia on multiple occasions. Additionally, the occurrence of a non-feminising strain of D. duebenum in Gammarus pulex suggests that different strains vary in their feminising ability, even within microsporidian species. The presence or absence of feminising ability in a particular microsporidian strain should not therefore be generalised to the species as a whole.