VSHimeras – fantastical creatures composed of different animal parts – have appeared across cultures representing the marvelous, the grotesque and the inherent complexity of identity. In ancient Greece, the chimera was part lion, part goat, part snake. In classic Japanese history, it consisted of a monkey, a tiger and a dog. However, modern biology maintains that humans can also to be chimerasharboring cells of different genetic origins.
Kristine Chua, a postdoctoral researcher in biology at the University of California, Santa Barbra, studies a form of chimerism – microchimerism – that occurs when cells are exchanged between the mother and fetus during pregnancy. Her work has the potential to help reinvent how scientists define the human body and open new avenues for understanding and improving maternal health.
As part of a group of researchers developing more sophisticated tools to study microchimerism, Chua is also advancing the practice of biological anthropology, a science that has grappled with diversity and ethical approaches to studying humans .
“(Microchimerism) is still such a small field that it presents challenges in terms of workflow, data collection and recruitment,” said Chua, who was recently named one of the STAT’s 2023 child prodigies. On the other hand, she said, “it’s very exciting because there is an opportunity to ask questions that haven’t been answered or to open up spaces for others to evolve our thinking. »
For decades, scientists have suspected that cells from developing offspring can escape the uterus and travel through the bloodstream to the mother’s body, eventually settling in her brain, heart, lungs and other organs. However, researchers have only recently begun to explore how these fetal cells might affect maternal health, in terms of potential benefits: faster wound healing And greater resistance to cancer – disadvantages, such as increased susceptibility to autoimmune diseases.
One of the difficulties of this growing science is the scarcity of fetal cells in the mother’s body, which ranges from 1 in 100,000 during pregnancy before declining to 1 in a million after birth.
According to Sing Sing Way, a professor and researcher at Cincinnati Children’s Medical Center, the lack of tools and laboratories to study microchimerism has prevented the field from getting the appreciation it deserves. “It’s fundamental to how we define what cells are in our body,” he said. “We are taught in high school that all the cells in our body are coded by our DNA…and (with a few exceptions) would fundamentally change the way our bodies function. »
HHistorically, scientists have studied microchimerism in mothers bearing sons, using the Y sex chromosome, found only in males, to distinguish maternal from fetal cells. In a 2015 study, for example, pathologists examining the bodies of 26 women who died during or just after pregnancy found cells with Y chromosomes in every organ studied, including the heart, brain, and kidneys.
Chua, who is a key part of an international research team – known as the Microchimerism, Human Health and Evolution project – is using more precise genetic markers that can detect differences in immune-related genes, which vary widely between mothers and fetuses. of both sexes.
Working with local hospitals and pregnant women who donate blood samples, Chua is exploring how microchimerism varies among pregnant people and the impact of this variation on the health of mother and baby. One hypothesis is that the maternal immune system, which can be triggered by and in turn attack fetal cells, plays a role in determining the degree of microchimerism in the parent. Going further, Chua also plans to study the role of stress and sociocultural factors that can modulate immune activity and thus alter the balance of maternal and fetal cells in the mother’s body.
“Kristine takes a pretty complex project and even adds another very important layer to it by putting it in the context of human social work,” said Amy Boddy, an associate professor of anthropology at the University of California, Santa Barbara, who directs the laboratory that Chua works.
According to Boddy, it is crucial to consider how sociocultural circumstances affect biology because humans are social animals. This type of effect cannot be observed in a petri dish or database and is an important piece of research that is now gaining attention.
“There aren’t a lot of people who can really talk both sides, when it comes to biology and cultural determinants of certain factors,” Boddy said. “Kristine is at the forefront of the field because she has expertise in both.
VSHua began navigating cultural and social dynamics long before he became a scientist. As a second-generation Chinese Filipino-American, she grew up in Los Angeles and nearby Rancho Cucamonga. In elementary school, Chua’s teachers asked her parents to stop speaking Filipino at home, so she could learn English faster.
“It was good at the time,” she said, “but by not speaking Filipino at home and only speaking pure English, the language was lost.”
With her mixed heritage, Chua remembers sometimes feeling culturally adrift among friends who claimed her way of doing things wasn’t uniquely Filipino or Chinese. “I don’t know if it was an identity crisis,” Chua said, “but I would think, ‘Uh, that’s really strange.'”
When Chua began studying anthropology at the University of California, Los Angeles, the field was grappling with questions of identity and power dynamics that resonated with his own personal experiences. In particular, anthropologists recognized the ethical complexity of extracting data from communities that were often less wealthy and more vulnerable than the Western countries from which most studies originated.
“I’m not saying that only people who are part of this community should do (anthropological) research, because then we wouldn’t get anywhere,” Chua said. “But it’s more important to recognize your background, your position, where you come from and how that can influence the questions you ask and certain interpretations.”
For Chua, who launched a pilot study in 2018 in the Philippines on how the stress of an authoritarian political regime could be transmitted from pregnant women to their unborn children, this meant rethinking her relationship with being Filipina as well as thinking about the best way to connect with her. local hospital staff and study participants.
A key step in this process was the relearning of language and cultural norms, as well as the personal engagement of study participants. For example, by collecting hair samples to measure long-term cortisol levels during pregnancy, Chua found that some women, who thought cutting their hair during pregnancy would cause the rest of their hair to fall out, were reluctant to give samples. This finding “was important to keep in mind when designing future studies requiring hair samples,” she said.
Chua also bonded with a woman who had been in labor for four days and kept coming back to the hospital. “By the second or third day, we were basically friends,” Chua said. “She would ask me where I was from and compare the cultural differences between the United States and the Philippines.”
Chua’s fieldwork changed his perception of his multicultural heritage. “Growing up, it wasn’t cool to be Asian… so I really tried to be more American,” she said. “But it was important to realize that I stand for much more than just being American.”
VSHua hopes this type of approach will inform new scientific standards.
“In terms of biological anthropology, there hasn’t traditionally been a lot of community engagement,” said Chua, who co-founded a DEI group as a graduate student at UCLA. “But there is pressure now to have better ethical practices, to do more than just come, get your education, leave and never return to the community you work with.”
For Chua, community engagement has included advising her Filipino research collaborators on how to install new laboratory equipment for their own studies, as well as working with pregnant women to improve studies on maternal mental health .
Talking to pregnant women in the Philippines about their experiences “made me think a lot about how there is no universal definition of stress” and the complexity of addressing mental health issues in populations that don’t don’t really talk about it, Chua said. Addressing mental health disparities in the United States, she explained, may require using different language that helps people from diverse backgrounds better express how they feel. “I think we need to ask questions about mental health, but the way they ask the question in hospitals and in the American medical system, they’re probably not asking questions in a way that would make people feel feel comfortable talking about it.”
According to Abigail Bigham, Chua’s graduate advisor and associate professor of anthropology at UCLA, listening to communities and helping them express their research needs and interests is an essential part of human studies. “Kristine is a perfect example of someone who thinks about people’s lives. the communities she works with and how she can contribute to how they conceptualize how they would like their well-being to improve.
In Bigham’s experience, anthropologists and biologists are slowly changing their attitudes toward the study of humans. Instead of viewing people as passive study subjects, researchers view them as active participants who can help shape the project and contribute key insights.
It’s an approach that Chua continues to refine in his current explorations of microchimerism and plans to incorporate into his future studies. “We’re not there yet. We’re still at that stage where we’re trying to make changes,” Chua said, “But it’s starting, and it’s really exciting.”