EVATAR – a box of reproductive tissues
Researchers have made a hand-sized device with all the tissues of the female reproductive system (1). They call it EVATAR (Eve + Avatar – a digital human).
EVATAR can be used to test if a new medicine is likely to cause hormonal problems or affect fertility in women.
Up until now, such tests could only be performed on human beings.
The device itself is like a box with many compartments. Each compartment contains tissues from the female reproductive organs. These include the ovaries, fallopian tube, uterus, and cervix.
The compartments are connected – allowing them to share nutrients and talk to each other using chemical signals (1).
Special electromagnetic valves control the flow of nutrients between compartments and a computer program controls the amount of nutrient in each compartment (1,2).
Photo credit : Northwestern University, Woodruff Lab
Why do we need this device?
Animals are not the best models for human disease or for studying how people will respond to a new medicine (3,4).
So what do we do when a study/ trial cannot ethically be performed in a human?
Traditionally, a scientist would take out some bits of a tissue from the human body and keep it alive in the lab (5).
They would then use these for further tests and studies.
Many human tissues, however, die or loose their function outside the body.
In the EVATAR device, researchers have succeeded in keeping all the tissues from the female reproductive system alive and functional for the 28-day menstrual cycle (1,6).
Testing for the behavior of tissues
During the menstrual cycle, the ovary in a woman’s body produces a mature egg. This mature egg is either fertilized or removed from the body(6)
The reproductive system, brain, and pituitary gland work together to make this happen(6).
The pituitary gland secretes gonadotrophins (namely Follicle Stimulating Hormone and Luteinizing Hormone).
The ovaries in the device responded to an external supply of these hormones by making their own chemical signals/ hormones – oestradiol, progesterone, Inhibin A and B.
The ovaries also produced a mature egg within the device.
Other tissues of the reproductive tract responded to the ovarian hormones.
The lining of the uterus – the endometrium, made more receptors to the hormones progesterone and estrogen at end of the 28-day cycle. The cells of the endometrium also multiplied, as expected during the menstrual cycle.
The ectocervix is the bit of the cervix that is externally exposed. It maintained it’s skin-like appearance and structure through the cycle.
This tissue also made receptors for the hormone progesterone only on day 0 and not on day 14 of the cycle, possibly controlled by the secretions of the ovary.
In the fallopian tube, the hair-like projections or cilia, that nudge the egg from the ovary into the uterus, were beating and functional even after 21 days in the device (7).
Researchers can now use this device to study infections and hormonal problems, as well as the reproductive system itself.
Inclusion of liver tissue in the EVATAR device
Tissue from the liver was included in the EVATAR model in one of the compartments.
The liver is not directly a part of the female reproductive system or cycle. However, it breaks down a new medicine in the body( 8).
After 28 days, the liver tissue looked normal and made a healthy amount of the protein, albumin, within the EVATAR device.
Researchers can now test a new medicine on the reproductive system and the liver simultaneously.
Want to know more about EVATAR and things mentioned in this article? Here are some links:
1. The study describing the construction of the EVATAR device – “A microfluidic culture model of the human reproductive tract and 28-day menstrual cycle” (https://www.nature.com/articles/ncomms14584)
2. Draper Labs on the technology behind EVATAR – http://www.draper.com/news/fighting-cancer-boosting-fertility-promise-first-female-reproductive-system-chip
3. “Man or mouse? Why drug research has taken the wrong turning”, October 2016, NewScientist. (https://www.newscientist.com/article/mg23230973-700-man-or-mouse/)
4. Why do we need animal models? https://speakingofresearch.com/facts/the-animal-model/
6. Dr. Woodruff explains the menstrual cycle https://www.coursera.org/learn/reproductive-health (Lecture 2.2)
7. Video of the cilia of the fallopian tube beating – https://www.nature.com/article-assets/npg/ncomms/2017/170328/ncomms14584/extref/ncomms14584-s2.mov
8. How does the liver work? (https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072577/)
Thank you, Kelly McKinnon, Hunter Rogers (Dr. Woodruff’s lab) and Bernadette Sztojka for your feedback.