So following on from the ISTS 2014 conference on tendons in Oxford a few weeks ago, there was lots of talk and debate during and afterwards about the role inflammation does or doesn't have in tendinopathy. One of these debaters was/is Ben Dean. Now regular readers to The Sports Physio will know Ben very well as he has written two other excellent blogs on the placebo effect here and another on pain here. Today Ben writes about the controversial topic on does inflammation exist in tendinopathy and if so, do we need to consider it, so with out further ado I will hand over to Ben…
Inflammation: a subject of great controversy but it shouldn’t be…
Many of the great controversies in science, and in this case tendon research, see a debate polarised into a ‘you’re either with us or against us’ type bun fight. I shall not be making this mistake, inflammation is neither the sole most important factor in tendinopathy, nor is it of no relevance to understanding and better treating what is this complex and multifactorial disease.
Too many people see things through their spectacles of vested interests; it is therefore no surprise that surgeons like surgery, injecting doctors like injections, physiotherapists like loading and quacktitioners like quackery.
Inflammation has a role in tendinopathy, the evidence is overwhelming and rather clear, to deny this is pretty much tantamount to flat earthing in my opinion.
Do I need to define inflammation for you first I hear you say? No. Why not? Well, definitions are never perfect and we will never agree on a definition, hence it is a totally pointless and futile exercise. Define tendon – do you get my point? There are numerous greys in every specific definition, forcing any definition by consensus is politics and not science, I shall simple demonstrate where the evidence lies and leave you to make up your minds.
Firstly to inflammatory cells, again this is another entity that is hard and almost impossible to define, so I shall not bother, I shall just describe several studies that have shown that cells which many would see as of an inflammatory phenotype are important in tendinopathy. Neil Millar has shown that numerous inflammatory cell types are increased in rotator cuff tendinopathy here. This excellent recent piece here shows similar findings that are linked with the resolution of symptoms in Achilles tendinopathy.
Some of our lab’s recent work has shown specific inflammatory cell markers are increased in painful versus pain free rotator cuff tendons here. Alex Scott et al have shown that increased mast cell numbers are present in patellar tendinopathy here. Plus what exactly are those round cells we see in early tendinopathy as seen here? I would suggest they may well be inflammatory in phenotype.
Secondly to inflammatory cytokines, Stephanie Dakin’s excellent review here also summarises much of strong evidence relating to the role of inflammation cytokines in tendon homeostasis, healing and tendinopathy, while Jonathan Rees’ excellent review here summarises much of the above better than I possibly could and is well worth a read, and its open access to all, and our recent review here showed that several of these are increased significantly in rotator cuff tendinopathy.
Johan Bagge’s excellent thesis here has demonstrated the presence of TNFalpha receptors and TNFalpha mRNA in Achilles tendon cells. While variations in the Interleukin genes have been linked to Achilles tendinopathy here.
The evidence goes on, on and on.
I’m damned if I know exactly what inflammation is, but there is undoubtedly a rapidly enlarging mass of evidence out there which shows that various strands of the inflammatory package are involved in tendon homeostasis, tendon healing and tendon disease.
The inflammatory process is incredible, these cells can notice and respond to tiny changes in microstructure, in a quite remarkable way that has come about as a result of thousands of year of evolution here.
We should not be arguing about silly definitions and semantics; we should be putting our effort into defining the role of inflammation in tendinopathy, as if we do this there is a very real chance that by developing a better understanding of disease, we will develop the effective treatments that we so badly want and need.
I would compare the current split in the tendon world to having two camps of people, one group are awake at night and protest that the sky is always black, while the other group is only awake in the day and refuse to accept that the sky is not always lit. Please wake up to inflammation being an undoubted factor of importance in the complex and multifactorial disease that is tendinopathy.
Note from Adam: I have turned back on the comments section for this blog as I think it would be a good discussion to have on this topic, and I'm hoping the trolls have returned back into their caves for a while… We shall see