Osteoarthritis is a painful, sometimes disabling and irreversible condition that affects many people. A recent study by researchers from Lund, Sweden and Switzerland confirms that X-ray imaging is an important tool for developing indicators that could aid early detection to slow progression.
Many people will experience osteoarthritis at some point in their lives. It is a painful and, many times, disabling joint condition that affects, for example, the hands or knees. The WHO estimates that the number of people with osteoarthritis will increase as life expectancy rises. Once the tissue has deteriorated, treatment cannot rebuild it. Early detection to slow progression is therefore important, but osteoarthritis is complex and not yet fully understood by science.
“Osteoarthritis leads to changes to the cartilage in the joint over many different length scales,” says Hanna Isaksson, professor at Lund University and senior author of the study. “Our recent work provides a new way to visualise the tissue degeneration in three dimensions on a microscopic scale. Although the technique is primarily a research tool, it gives us a much better understanding of how the cartilage deteriorates. That knowledge is essential for developing better disease indicators that could be used in healthcare tests. It could improve how disease progression is evaluated, and ultimately support the development of treatments that can slow or prevent cartilage degeneration.”
The technique that the researchers used to image the cartilage, so-called three-dimensional X-ray phase-contrast microtomography, offers additional advantages over traditional tissue imaging methods. Traditional methods, such as histology, require destructive staining and slicing, which limits the ability to conduct additional studies of the same tissue using other methods. It could also potentially alter the tissue.
“With the new X-ray method, we can image human cartilage with a level of detail that approaches conventional methods, but preserves the tissue close to its native state. Until now, by studying only thin slices, much of the three-dimensional structure has been lost. With the new method, we can study the entire tissue and see more of how both the cells and the surrounding cartilage change as osteoarthritis develops,” says Hanna Isaksson.
The researchers did their main research at the Swiss Light Source, a facility similar to MAX IV in Switzerland, and complementary experiments at MAX IV’s ForMAX beamline.
“At Swiss Light Source, we could image many and relatively large cartilage samples while still capturing individual cartilage cells. To validate our image analysis, however, we also needed images with substantially higher resolution. That is why we performed complementary experiments at the ForMAX beamline at MAX IV,” says Hanna Isaksson. “MAX IV helped ensure that the quantitative measurements from our main dataset were reliable.”
The nondestructive X-ray imaging opens exciting possibilities for further research.
“The next step is to combine this imaging technique with experiments that investigate how cartilage behaves under mechanical loading. We will be able to study tissue while it is being compressed, allowing us to directly observe how healthy and osteoarthritic cartilage responds to loading,” says Hanna Isaksson.
The study was a collaboration between the Biomechanics group at LTH and the Clinical Epidemiology unit at Medical Faculty of Lund University, as well as the beamline scientists at SLS and MAX IV.
