3Rs-Centre Utrecht Life Sciences

Faculteit Dierengeneeskunde

February 2018
Development of a human uterine model for research on female reproduction

In developmental and reproductive toxicology studies in which potentially harmful substances must be tested, many laboratory animals are still being used. There is much to be gained in this field regarding the reduction, refinement and replacement of animal studies. There is also a great demand for more human relevant models in reproductive toxicology as the (rodent) animal and human reproductive cycle differ in many aspects. At the Institute for Risk Assessment Sciences (IRAS) at Utrecht University, Annick van den Brand and her colleagues therefore have developed an endometrial model made of human uterine cells, in order to better test the effects of potentially harmful substances on the uterus.
Epidemiological studies have found a link between the occurrence of uterine diseases like endometriosis, and uterine or endometrial cancer, and the exposure to substances in the environment, like hormone-disrupting substances, dioxins, and drugs. However, research on female reproduction is an underexplored field in science and in the regulatory test strategies, which currently lack good predictive (in vitro) models for humans. After all, animal studies are difficult to translate to the human situation because the uterine physiology and hormone regulation of the reproductive cycle in (rodent) animals is significantly different.
Endometrium model
Together with dr. Majorie van Duursen, Annick van den Brand has developed a 3D in vitro endometrial model using endometrial cells from the human uterus. In collaboration with the St. Antonius hospital, they have gained access to healthy uterine tissue that is normally thrown away after a hysterectomy. From this, two types of cells from the endometrium (the inner wall of the uterus) are isolated and can be further cultured in the laboratory. Subsequently, these cells are combined again into a 3D model so that the cells can communicate with each other as they would do in vivo. The cells are exposed to relevant hormone concentrations to mimic the different phases of the female reproductive cycle. The model has been shown to react to hormones as endometrial cells in the in vivo uterus do. By also exposing this in vitro model to potentially harmful substances, it is possible to check whether these substances can disrupt this mimicked hormone balance in the uterus.
Van den Brand: “Once this model is validated, we hope that the results from this model can be used to establish new guidelines to test the effect of substances on female reproduction without the use of laboratory animals. For example, the endometrium model can be used in the preclinical phase of drug development, but can also prevent new, hard-to-translate animal studies from being implemented in regulatory test strategies.” Reducing the number of test substances by pre-selection with new test methods, like this endometrium model, can save the hundreds of experimental animals that are currently used for the testing of each substance. In addition, the model can be used to improve insights into the pathology of uterine diseases and to determine biomarkers that can be used to test the effect of harmful substances on female reproduction.

Primary tissue of the human uterine wall                   Annick van den Brand

Future research
The development of the uterine model was originally funded by a pharmaceutical company that wished to test the effect of a newly developed drug on the endometrium. However, after the first test results being successful, Van den Brand and her colleagues are looking for additional funding to expand the use of the model to other purposes. For example, fertility disorders are increasingly linked to the exposure to harmful substances from the environment. Therefore, Van den Brand would like to extend this uterus model in such a way that the implantation of embryos in the endometrium can be investigated. “In addition to detecting substances that have a negative influence on the implantation of an embryo, we could also use this model to study possibilities for optimizing fertility treatments, for example,” explains Van den Brand.

The Institute for Risk Assessment Sciences (IRAS) is a department within the faculty of Veterinary Medicine of Utrecht University (UU). Annick van den Brand works at the Toxicology division of IRAS with a focus on endocrine disruption of the female reproductive system.