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Mimicking vaginal cells and microbiome interactions on chip microfluidic culture

Reporter and Curator: Dr. Sudipta Saha, Ph.D.

Scientists at Harvard University’s Wyss Institute for Biologically Inspired Engineering have developed the world’s first “vagina-on-a-chip,” which uses living cells and bacteria to mimic the microbial environment of the human vagina. It could help to test drugs against bacterial vaginosis, a common microbial imbalance that makes millions of people more susceptible to sexually transmitted diseases and puts them at risk of preterm delivery when pregnant. Vaginal health is difficult to study in a laboratory setting partly because laboratory animals have “totally different microbiomes” than humans. To address this, scientists have created an unique chip, which is an inch-long, rectangular polymer case containing live human vaginal tissue from a donor and a flow of estrogen-carrying material to simulate vaginal mucus.

The organs-on-a-chip mimic real bodily function, making it easier to study diseases and test drugs. Previous examples include models of the lungs and the intestines. In this case, the tissue acts like that of a real vagina in some important ways. It even responds to changes in estrogen by adjusting the expression of certain genes. And it can grow a humanlike microbiome dominated by “good” or “bad” bacteria. The researchers have demonstrated that Lactobacilli growing on the chip’s tissue help to maintain a low pH by producing lactic acid. Conversely, if the researchers introduce Gardnerella, the chip develops a higher pH, cell damage and increased inflammation: classic bacterial vaginosis signs. So, the chip can demonstrate how a healthy / unhealthy microbiome affects the vagina.

The next step is personalization or subject specific culture from individuals. The chip is a real leap forward, it has the prospect of testing how typical antibiotic treatments against bacterial vaginosis affect the different bacterial strains. Critics of organ-on-a-chip technology often raise the point that it models organs in isolation from the rest of the body. There are limitations such as many researchers are interested in vaginal microbiome changes that occur during pregnancy because of the link between bacterial vaginosis and labor complications. Although the chip’s tissue responds to estrogen, but it does not fully mimic pregnancy without feedback loops from other organs. The researchers are already working on connecting the vagina chip to a cervix chip, which could better represent the larger reproductive system.

All these information indicate that the human vagina chip offers a new model to study host-vaginal microbiome interactions in both optimal and non-optimal states, as well as providing a human relevant preclinical model for development and testing of reproductive therapeutics, including live bio-therapeutics products for bacterial vaginosis. This microfluidic human vagina chip that enables flow through an open epithelial lumen also offers a unique advantage for studies on the effect of cervicovaginal mucus on vaginal health as clinical mucus samples or commercially available mucins can be flowed through this channel. The role of resident and circulating immune cells in host-microbiome interactions also can be explored by incorporating these cells into the vagina chip in the future, as this has been successfully done in various other organ chip models.

References:

https://www.scientificamerican.com/article/first-vagina-on-a-chip-will-help-researchers-test-drugs/

https://www.webmd.com/infertility-and-reproduction/news/20230209/scientists-create-vagina-on-chip-what-to-know

https://www.livescience.com/vagina-on-a-chip

https://link.springer.com/article/10.1186/s40168-022-01400-1

https://www.nature.com/articles/s41585-022-00717-8