They’re called “organoids,” miniature functioning models of organs grown in vitro that are complete with realistic and working micro-anatomies. As the techniques for creating them have become more sophisticated, their value to the scientific community – and to your future health – has grown appreciably.

In fact, scientists at the University of Cambridge in the UK just created an organoid lining of the uterus and our understanding of events that occur during the menstrual cycle and events during early pregnancy when the placenta is established has already benefited considerably. Up until now, these events were impossible to capture in a woman, and researchers have had to rely upon animal studies.

The endometrium – that mucosal lining inside the uterus – changes over the course of the menstrual cycle. Its composition becomes thicker and rich with blood vessels in preparation for pregnancy, but if the woman does not conceive, the uterus discards this tissue, causing the woman's period.

The British researchers were able to grow the organoids in culture from cells derived from endometrial tissue and maintain the organoids in culture for several months, faithfully reproducing the pattern of activity of genes in the lining of the uterus. The lab-grown womb also responded to female sex hormones and early pregnancy signals, actually secreting the “uterine milk” proteins that nourish the embryo during the first months of pregnancy.

"Events in early pregnancy lay the foundations for a successful birth, and our new technique should provide a window into these events," noted Professor Graham Burton joint senior author of the study. "There's increasing evidence that complications of pregnancy, such as restricted growth of the fetus, stillbirth and pre-eclampsia – which appear later in pregnancy – have their origins around the time of implantation, when the placenta begins to develop."

The scientists are using their organoid uterus to help them more completely understand how a developing fertilized egg – known as the 'conceptus' – gets implanted into the wall of the uterus. They have learned that the conceptus seems to send signals to the endometrial glands that then stimulate the development of the placenta. In this way, the conceptus is able to stimulate its own development through a 'dialogue' with the mother; if it fails, the result is loss of the pregnancy or severe growth restriction of the fetus.

Next steps? The researchers are looking to grow organoids from endometrial cancer cells. They hope this will allow them to model and understand diseases of the endometrium, including cancer of the uterus and endometriosis.

The research has been published in the journal Nature Cell Biology.