Interview with Professor Jo Nijs


Active Member
Jo Nijs is a Professor of Physiotherapy at the Vrije University of Brussels, Belgum and a manual therapist at the University Hospital Brussels. He is holder of the Chair, ‘Exercise Immunology and Chronic Fatigue in Health and Disease’ at the Vrije University of Brussels created by the research group Pain In Motion and the European College for Decongestive Lymphatic Therapy. His clinical and scientific research focuses on the treatment of “inexplicable’’ chronic pain and ME.

How did you get involved in the field of ME research?

In 1999 I started working for professor Kenny De Meirleir, and I did my PhD with him, studying fatigue and pain in patients with ME.

Can you tell us about some of your current research into ME?

Our work in ME is currently focused on epigenetics. With our research on epigenetics, we hope to unravel the increased sensitivity of the central nervous system (‘central sensitization’) as commonly seen in patients with ME. You can check out our latest study report here:
In addition, our work on nutrition and central nervous system sensitization is of relevance to ME as well, you can check it out at

Many people with ME experience a variety of problems with regard to pain. These pain issues range from muscle pain to headaches. There are some doctors who argue that the cause of muscle pain may be polymyalgia rheumatica when muscles become allergic to gut microbes. Other suggested causes of pain in people with ME are poor energy delivery mechanisms and magnesium deficiencies.

What do you think may be causing these pain issues for people with ME?

RE: These are all interesting ideas, some of which have been examined in scientific studies. Our current understanding of pain in patients with ME suggests that central nervous system sensitization is the underlying mechanism. This fits well within the idea of neuroinflammation in ME: neuroinflammation can trigger and sustain central nervous system sensitization (

At the moment people with ME who have pain issues may be prescribed painkillers by their GP. Based on your research and knowledge of this field what you think is the best approach to dealing with pain issues facing people with ME?

RE: Our work on epigenetic mechanisms in relation to central sensitization holds the potential to identify new therapeutic drug targets, but right now there is no effective drug that can take away the pain. However, poor sleep, lack of physical activity, and stress intolerance are all key factors that contribute to central nervous system sensitization. Conservative ways of improving sleep, increasing levels of physical activity and improving stress tolerance are the best-evidence options for reducing pain.

If a person has chronic pain issues caused by persistent muscle stiffness or spasm some doctors suggest that it may be a learned response whereby the body increases the pain signal to try to elicit a response that will heal the pain.

Is there a neuro-psychological element to the chronic pain that many people with ME experience?

RE: Cognitive-emotional factors are known to increase the sensitivity of the central nervous system, that’s why interventions that target those cognitive-emotional factors result in decreased sensitivity of the central nervous system. Of course, they cannot explain the full clinical picture, but they are an important piece of the puzzle.

Pain is essential for the survival of all animals including human beings. It makes us protect the affected part of the body so that healing and repair can take place. However, if pain is persistent it can produce other reactions in the body that are detrimental to our health.

RE: Exactly! Acute pain protects us, persistent pain is typically maladaptive. In any situation, pain is an output product of the brain (i.e. a message from the brain to alert us that something might be wrong or that you are in a dangerous situation). In persistent pain states, the brain keeps on producing danger messages (=pain), even though tissues have healed long time ago. Persistent pain often reflects increased sensitivity of the central nervous system. Therefore, the question is: what causes / sustains this increased sensitivity of the central nervous system? Targeting those factors is the way to go if you want pain relief.

Can persistent pain exacerbate the fatigue someone may be experiencing?

RE: Pain in itself can be fatiguing, but I feel it’s more important to address the factors sustaining symptoms such as fatigue and pain.


(definition taken from me-pedia)

"is a term used to describe activation of the resident immune cells in the

central nervous system (CNS) Neuroinflammation is a symptom of many diseases and thought to be a part of ME. Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis are illnesses in which the brain experiences decline in structure and function, and also where it shows clear signs of neuroinflammation. Inflammation of the brain is linked to activated microglia, cytokine presence in the brain,[6] and changes in the neurochemicals produced by the brain.[7] These effects also occur in ME which is why researchers are searching to more strongly show neuroinflammation in these patients.”

(definition taken from CDC website)

‘’Your genes play an important role in your health, but so do your behaviors and environment, such as what you eat and how physically active you are. Epigenetics is the study of how your behaviors and environment can cause changes that affect the way your genes work. Unlike genetic changes, epigenetic changes are reversible and do not change your DNA sequence, but they can change how your body reads a DNA sequence.

Gene expression refers to how often or when proteins are created from the instructions within your genes. While genetic changes can alter which protein is made, epigenetic changes affect gene expression to turn genes “on” and “off.” Since your environment and behaviors, such as diet and exercise, can result in epigenetic changes, it is easy to see the connection between your genes and your behaviors and environment.’’and is characterized by a host of cellular and molecular changes within the brain.''

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