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How EPA’s influence the chemicals of inflammation and repair

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The term ‘anti-inflammatory’ has been thrown around in therapy for years. The anti-inflammatory effect has long been described as one of the major benefits of therapy and I still see this term being used regularly. This week we will discuss how this term is outdated in relation to tissue repair and why in fact, being pro-inflammatory is actually the major benefit we should all be striving to achieve. We will also look at how electrophysical agents (EPA’s) can kick start the healing process.

Pain and swelling are signs of inflammation and it is true that we want to reduce any negative impact that inflammatory fluid has on the animal in the early stages of injury. I am not suggesting that we try to stir that up or augment acute inflammation. It is not a good idea, in the first few days of injury (or any other time for that matter), to ignore the pain and swelling and carry on regardless. However, oedema is just a consequence of inflammation and not inflammation itself (by the way it is actually there for good reason and has an important role to play but that’s for another Knowledge Nibble).

The healing process is VERY sophisticated and where the conditions for healing are absolutely optimal, it will follow a mapped out series of events which take the injury from acute to full repair. It is easy to lose sight of how awesome this process is, due to the fact that the patients we work with are most often in a compromised healing state. The reason we are seeing them is because something has gone wrong! But let’s be clear, if we are seeing patients with inflammation, at say 10, 12 weeks after the initial injury, this is not normal. In these cases the patient is stuck in the inflammatory phase and it is our job to push them through to the next phase of proliferation. It is not our job to ‘reduce’ the inflammation or use an intervention that produces an ‘anti-inflammatory’ effect.

What do chemicals have to do with all this?....

Inflammation should not be seen as the enemy. It is absolutely essential to the repair process. A very impressive cascade of events take the injured tissue on a journey through the inflammatory phase, doing its job of clearing away debris and providing a fibrin meshwork as a foundation on which migrating cells can settle. These events are controlled by chemical mediators; you can think of these mediators as little messengers which talk to blood vessels and cells. They effectively give the orders to switch on, ramp up and finally resolve inflammation, then trigger the signals to move to the next stage. It’s all driven by chemical mediators and these are released from cells (or at least they should be). These messages continue throughout the next stage of proliferation, where the material required for repair is produced and into the final stage of remodelling where this material is organised and strengthened.

What is the problem then?

Inflammation can get stuck for many reasons. For example, if the original irritant is still there (infection, foreign body, mechanical overload etc) then inflammation will persist; this irritant will need to be addressed. Other factors such as age, general health, nutrition and comorbidities can play a part. But to cut a long story short, the cells that are responsible for releasing these essential chemical messages are not working well. They are slow and lazy. As you can deduce from the above, no chemicals = no action. In non-healing injuries we have reached a stalemate!

Where can therapy help?

Somehow, we need to energise these cells and get them doing their job again. There are various ways that we can influence cellular activity which include manual techniques and exercise. But for the sake of this article we will consider the effect of EPA’s on the cell.

Electrophysical Agents (EPA’s) are modalities that we use in therapy (Laser/photobiomodulation, ultrasound etc). Essentially an EPA is a device which delivers energy to the tissues to bring about a physiological change. This energy may be in the form of a soundwave, electromagnetic wave or a muscle/nerve stimulating current. Although the different modalities have subtle differences in the physiological effects they bring about, fundamentally, they are all acting on the cell to produce a change.

The low energies produced by EPA’s gently stimulate the cell membrane and increase its permeability. This means a whole lot of calcium gets transported across the membrane which gets the cell very excited. The proper term is cellular up-regulation and what this means is that the cell starts functioning as it should and doing all of its jobs more quickly and more efficiently. In the context of what we have been looking at here, the cells up-regulate the release of the essential chemical mediators to jump start the process. How cool is that?!!!

I would like to finish up with giving you an example of how this works in practice. Let’s consider a chronic wound. The modality I would select for a chronic wound would be a photobiomodulation device (PBM). It is a relatively superficial treatment which is well supported in the literature for wound repair. Chronic wounds can go a long time without healing and will sometimes be addressed with a skin graft; this is not always successful.

In this scenario we will have lots of sleepy macrophages. One of the roles of a macrophage is to release chemicals which stimulate fibroblasts. Fibroblasts produce collagen and extracellular matrix which are the building blocks we need to make the final repair. So, if the macrophage doesn’t release the chemicals, the fibroblasts are not triggered and the repair material is not produced. And it doesn’t stop there!

Another job of the macrophage is to release the chemicals that stimulate angiogenesis (growth of blood vessels). Angiogenesis is essential for healing as it provides the path of oxygen delivery to the healing site. Fibroblasts need oxygen to produce the building materials; no oxygen = no materials. It all comes back to the sleepy macrophages! The use of our EPA’s can wake up the macrophages and get them excited to do their job, triggering the chemical cascade.

There is, of course, much more to this and I have deliberately provided a simplified account. There are also other physiological effects of EPA application with regard to tissue bioelectrics and pain mechanisms. But I hope that you can see how important it is that we don’t attempt to reduce inflammation during tissue healing and how exciting it is that we can actually influence the inflammatory process and provide the body with the jump start it needs for repair!

If this Knowledge Nibble has piqued your interest in learning more about how the various EPA’s interact with the body to bring about healing, then you might be interested in our new series of courses in EPA’s. The first course in the series, Photobiomodulation starts on 28th February 2022 and the early bird discount of 20% is currently available.


  1. If you use EPA’s in your practice, spend a little time completing some reading on the modalities you use. Use this as a refresh. It is probably a little while since you trained on the modality so review the settings and the protocols you use and ensure you know exactly how the treatment interacts with the body. We can get a bit stuck in a rut, favouring one piece of equipment and it is easy to forget the details about what it actually does!
  2. Review any literature you use in your practice and on your website and see where you might have used the term ‘anti-inflammatory’. Have a think about changing the wording a little to reflect anything that you have learnt today. 
  3. If you don’t use any EPA’s in your practice, then choose something you have an interest in and spend a little time reading manufacturers’ websites. What claims do they make about inflammation? Take a critical approach to what you read;)

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