Scientists are one step closer to healing tendon disease in people and animals

Researchers at Queen Mary University of London are now closer to understanding tendinopathy, a common condition that can cause persistent pain and impaired movement in people and many animals.  

In recent research, published in Advanced Science, scientists identified a population of tendon cells that is particularly sensitive to changes in the physical environment around them, providing new insight into how tendon tissue may respond to the changes associated with ageing or injury. 

Tendons are not made up of one uniform population of cells, instead they contain different regions with distinct physical environments. The researchers focused on cells within the interfascicular matrix (IFM) – the softer tissue that connects the collagen bundles, or fascicles, that make up a tendon. 

The team successfully isolated and maintained populations of IFM cells and fascicular matrix (FM) cells, allowing them to compare how the two cell populations respond to changes in mechanical stiffness. While the prior were highly sensitive to their surroundings, the latter remained largely unchanged.  

When exposed to stiff substrates, the IFM cells changed their internal structure, rapidly altered the expression of genes associated with tendon function and the extracellular matrix production, and showed a decline in their ability to proliferate. Importantly, when IFM cells were returned to softer, IFM-like substrates, their morphology and ability to proliferate recovered, while some of the changes in gene expression were also restored. 

“Our findings show that different tendon cells can respond very differently to changes in their mechanical environment. This is important because tendons can undergo changes in their structure and stiffness during disease, and we need to understand how individual cell populations respond to those changes.” says Dr Simon Grossemy, the lead researcher from Queen Mary University of London. 

The Principal Investigator, Professor Hazel Screen added “The recovery we observed when IFM cells were returned to a softer environment was particularly interesting. It highlights how the physical environment is an important factor in maintaining the behaviour and characteristics of these cells.” 

For people living with tendon conditions, the research provides a new perspective on how tissue changes may affect the resident cells and maintain tissue health or drive disease. Tendinopathy can be difficult to treat, partly because the biological processes underlying tendon degeneration are still not fully understood. By identifying a highly mechanosensitive cell population, the research gives scientists a new way to investigate how changes in the tendon environment could influence cellular behaviour. 

They could also support research into tendon health in animals. Tendon injuries are an important concern in horses, whose tendons experience substantial mechanical forces during movement and athletic activity. A better understanding of how tendon cells respond to their physical surroundings could help researchers investigate the biological processes involved in tendon injury and recovery across species. 

Even though the study does not establish that IFM cells directly cause tendinopathy or provide a new treatment, it provides an exciting new experimental framework that enables researchers to investigate these questions. 

The team has also developed a defined laboratory culture framework that helps maintain important characteristics of IFM cells in vitro. This is significant because cells can change their behaviour when removed from their natural tissue environment. 

The researchers hope that their findings will contribute to a more detailed understanding of tendon biology and support future work towards more targeted approaches to preventing, managing and repairing tendon damage in people and animals. 

You can read the full research via the following link.