Uncovering clues to the sex disparity in tissue in osteoarthritis cases

Thanks to the popularity of the Star Trek television series and movies, you’ve probably heard the quote“Space: The final frontier.” But for one medical researcher at the University of Alberta, space actually represents the beginning of opportunities to uncover the secret to ailments affecting people here on Earth.

Adetola Adesida’s research team works on rebuilding cartilage and meniscus tissue using adult stem cells. This is important work, says the professor in the Faculty of Medicine & Dentistry’s Department of Surgery, because while our bones get a lot of credit for keeping us upright, cartilage is found extensively throughout the human body and is especially important for healthy joints. “I've been looking at how to make cartilage for those who need it from their own bodies,” says Adesida.

His recent work takes a step beyond building replacement tissue, focusing on using microgravity to unlock the mystery of osteoarthritis — the breakdown of cartilage tissue in joints. Specifically, he wants to understand why this often-debilitating condition affects females twice as often as, and earlier than, it affects males. 

Adesida and the research team took a cue from the NASA Twins Study, a study involving identical twin astronauts. Because of their identical genetic structure, twins offer a perfect basis for comparison of how genes behave in different environments. The Twins Study demonstrated, among other things, that aging occurs more rapidly in space. For researchers, this offers the advantage of being able to observe changes in human tissue that take many years to occur, but in a more abbreviated time frame than is possible on Earth. 

 “We know that the microgravity environment of space does accelerate certain things that have an impact on our health on earth,” he explains. “So we're using that microgravity platform to look at a variety of things.” In a paper recently published in Nature, “Transcriptomic response of bioengineered human cartilage to parabolic flight microgravity is sex-dependent,” Adesida shares the team’s findings from their own study done via parabolic flight — a stomach-churning airplane ride that mimics the weightlessness environment of space.

In their study, the team sent cartilage from the adult stem cells of bone marrow collected from three males and three females on a parabolic flight, which allowed them to isolate the RNA sequence in tissue samples in a weightless environment. “We found genes that were associated with the development of osteoarthritis only in the tissue samples from females,” says Adesida, “which tells us our study was able to mimic, to some extent, the early incidence of osteoarthritis in females. We know that females tend to develop osteoarthritis about 10 years earlier than males. Males usually get it around the age of 50, but females tend to develop the condition around age 40.” 

Identifying these genes offers the potential to look for the proteins they express, and subsequently look for early signs of osteoarthritis so action can be taken to keep joints healthy. Understanding what triggers osteoarthritis could also help researchers find ways to prevent it.

“Maybe we need to be incorporating deliberate or intentional protocols of exercise every day, especially when we know that we're reaching that age, right? These are some of the types of things that we can do,” says Adesida.

Finding out how and why osteoarthritis affects people and taking steps to prevent it is important.  It’s a condition that affects about seven per cent of the global population, impacting people’s ability to work and enjoy an active and pain-free quality of life as we age. It’s also a significant financial burden on the Canadian health-care system; an estimated total direct cost per year of $3 billion is spent on treating the condition.

For now, Adesida plans to continue his out-of-this-world research, thanks to support from the Women and Children's Health Research Institute (WCHRI), of which he is a member, and the Canadian Space Agency. “I'm very much involved in space health. It's a wonderful platform to look at things that really affect health on Earth.”

This research was supported by the following agencies: the National Research Council of Canada (NRC), NRC’s Aerospace Flight Research Laboratory, Students for the Exploration and Development of Space -Canada, University of Alberta Engineering Students’ Society, University of Alberta Faculty of Engineering, Canadian Institutes of Health Research, Cliff Lede Family Charitable Foundation through the University Hospital Foundation, Alberta Women’s Health Foundation through WCHRI and the University of Alberta Pilot Seed Grant Program.