Vaping while pregnant: USask researchers develop vital tool to study risks

Dr. Tat Chuan Cham (DVM) is a University of Saskatchewan (USask) PhD student who recently developed an in vitro (petri dish-grown) artificial pig testis — a vital tool that’s helping him to answer important questions about the effects of many toxicants including those produced from vapes.

The research team’s most recent findings were published this month in Reproductive Toxicology, while other related work was previously published in the open-access journal Cells.   

Since pigs and humans share many similarities in anatomy and physiology, the pig is an excellent animal model that offers an opportunity for researchers to gain insight into human biological processes while answering a multitude of questions involving human health.

Cham is especially interested in studying the effects of vaping on a developing fetus — his response to a concerning trend among some pregnant women who view vaping as a safer alternative to smoking although its effects are still largely unknown.

While statistics on vaping during pregnancy are limited, the U.S. Centers for Disease Control states that seven per cent of women report using e-cigarettes around the time of pregnancy — 1.4 per cent report vaping during the last three months of their term.

“[Many toxicants have] been reported to pass through the placental barrier [and] their effect on the fetuses’ developing testis is unknown,” says Cham, whose supervisor is Dr. Ali Honaramooz (DVM, PhD), a professor at the Western College of Veterinary Medicine (WCVM).

“[By] using our system, we will be able to test this by mimicking what happens in those exposed fetuses.”

Cham adds that most vaping liquids contain nicotine, a drug that is known to pass through the placental barrier. In addition, the liquids also contain unnatural flavours and additives that are largely untested in terms of their effects on a growing fetus.

Using a process called testis organogenesis, Cham created a three-dimensional structure known as a testis organoid that replicates the cellular composition and the functional capability of an actual testis – the male reproductive organ which produces spermatozoa.

Cham initiated the process of testis organogenesis by taking the testis of a one-week-old piglet and breaking down its structure into individual cells.

“If you directly use the testis tissue [rather than first starting with single cells] the structure is already formed so you don’t see that process of testis organogenesis,” says Cham.

Like members of a dance troupe, these individual cells know the routine. Once they’re placed on the proper stage with the right environmental factors, they start the orchestrated performance that unites them with their neighbouring testicular cells.

Although each individual cell appears to be functioning with no purpose or intention, a step back to see the big picture makes the goal evident. Each cell plays an essential part in the group as it moves to create a testis formation.

Two essential types of cells play very different yet irreplaceable roles in this performance. Germ cells are the reproductive cells — once settled and mature in their final destination, they become the precursor for a lifetime production of sperm.

The other cells are mostly somatic cells, and they fulfil their final role by supporting the germ cells and producing hormones such as testosterone.

Within 24 hours the cells come together in a rough, round formation known as a cell spheroid, and once exposed to a supplement rich growing media, they return to their original cord structure as if nothing had happened. With no needed direction or assistance, these cells making up the developing artificial testis organoid continue to move, grow and proliferate.

The end goal for the cells is a structural cord formation that houses the germ cells and supporting somatic cells. Once this formation is surrounded by hormone-producing somatic cells intertwined with blood vessels and connective tissue, the cells will have reached their final position. However, their role there will never stop as the organoid continues to mature.

This artificial testis system so closely mimics that of a fetus and opens many doors for research that would be impossible otherwise — given the obvious ethical concerns involved with testing on pregnant women.

Although Cham’s investigation of the effects of vaping is still in its very early stages, the list of unknowns with how testicular cells are affected is alarming. Scientists have confirmed that any damage to the cells in the testis during development can lead to lifelong problems for an individual, including infertility or testicular cancer.

“Damage to a cell that results in mutated DNA gives the cells a chance to become cancerous.” says Cham.

The Natural Sciences and Engineering Council of Canada (NSERC) is providing financial support for this research project.

Lauren Letham of Kamloops, B.C., is a third-year veterinary student at the WCVM who worked as a summer research student in 2023. Her story is part of a series of articles written by WCVM summer research students.