Pain after inflammation or tissue damage usually disappears over time. But this does not happen in a significant proportion of patients with inflammatory diseases. They continue to suffer from pain, even after the inflammation has disappeared. In total, as many as one in five people have chronic pain. A large proportion of them have an inflammatory condition, such as joint rheumatism, osteoarthritis or an inflammatory disease of the intestines (such as Crohn's disease). To develop new treatments for this type of persistent pain, experts must first understand how inflammatory pain normally arises. And more importantly: how this kind of pain disappears again.
Delivering energy factories
The research group of dr. Niels Eijkelkamp from the Center for Translational Immunology (CTI) has been trying to understand how (chronic) pain works for some time. At the end of last year, his group, together with the group of prof. Linde Meyaard, een a scientific article about the role macrophages play in pain
Macrophages are immune cells that attack and eat pathogens. “We have known for some time that these cells have many more tasks,” says Eijkelkamp. “They also play a role in eliminating pain.” The researchers discovered that macrophages can deliver mitochondria (the 'energy factories' of the cell) to nerve cells. These nerve cells transmit pain signals from the inflamed tissue, which is why a person feels pain. “We discovered that releasing mitochondria helps stop the pain,” says Eijkelkamp.
How this works? Unfortunately, that is not yet clear. Eijkelkamp: “As you often see in scientific research, our study has also raised questions.” With the money that NWO is now making available, the pain expert can take the next step. He will do lab research with an immunologist dr. Michiel van der Vlist, who knows a lot about the immune system (and therefore about macrophages).
The two experts hope to better understand how the nervous system and immune system talk to each other. They will achieve this by answering a number of questions. Questions such as: how do nerve cells attract macrophages that can produce pain? What Causes Macrophages to Expand Pain? And what exactly changes in nerve cells when they receive mitochondria (the 'energy factories') from macrophages?
By answering these questions, the researchers ultimately hope to better understand how pain disappears after inflammation. “We can use that knowledge to develop new treatments for chronic pain,” says Van der Vlist. “How great would it be if we could one day help 1.5 billion people get rid of their chronic pain?”