Bioreactor infrastructure for organoid culture in human models of reproductive diseases

Approximately 15% of all clinically recognised pregnancies end in miscarriage, mostly before 12 weeks of gestation.

Apart from physical trauma (pain, bleeding, and infection), each miscarriage compounds the risk of significant psychological morbidity (depression, post-traumatic stress disorder, and suicide) and obstetrical complications in a future ongoing pregnancy, foremost preterm birth.

Globally, preterm birth, affects 5-18% of live births, although the incidence varies dependent on ethnicity and socioeconomic factors.

Preterm birth is the single most important cause of neonatal morbidity and mortality, especially in "very preterm" infants (those born before 32 weeks' gestation).

The main roadblock in developing effective strategies for miscarriage and preterm birth prevention is the lack of suitable model systems that recapitulate human-specific reproductive traits.

Although animal models, which can vary from mild to severe are widely used, they do not approximate human pregnancy, and have not yielded effective treatments.

We have had success in pioneering an assembloid model of the human endometrium that recapitulates the peri implantation endometrium.

However, implantation in the human is deeply interstitial, and involves disruption of the inner myometrial layer, also termed the junctional zone (JZ). Successful placentation depends on trophoblast invasion of the JZ, which forms the placental bed.

Importantly, a spectrum of obstetrical disorders, including preterm birth, is caused by failure of invading trophoblast to sufficiently remodel the JZ and its vessels.

Through NC3Rs funding we have been working on a project that involves creating a JZ by the addition of myometrial cells to our lab grown assembloids, creating a superior model to parse the mechanisms of prevalent pregnancy disorders.

Importantly, when validated, a whole series of animal experiments in species including mice, rats, guinea pigs and non-human primates could be replaced when undertaking studies of human pregnancy and implantation.

Whilst developing this new system we have been working on techniques that not only generate novel models but also reduce and refine existing methods in terms of their impact on animal usage.

We have been using recently developed bioreactor technology that reduces the need for Matrigel by over 100-fold thereby reducing the high cost and animal wastage created by using this product.

In this proposal we will build on our recent innovations from our NC3Rs project grant by adding bioreactor capacity to our laboratories at Warwick, refining the techniques still further, whilst expanding protocols into other fields of reproductive medicine such as germ line differentiation in stem cells and endometriosis.