Bacteria, Bones and your Microbiota

Pondering bacteria? Well I am and why not after a chance visit to the wonderful Micropia in Amsterdam ( www.micropia.nl/en) and a nod to the BBC’s latest attempt to ‘wow’ you on the ‘superhero’ nature of bacteria (http://www.bbc.co.uk/programmes/articles/3k2dltDPlD8hGMNq6WSDWSd/seven-things-you-didn-t-know-about-bacteria).

Like everyone else, you have about 3 trillion bacteria in your gut and about…I don’t know… one thousand gazillion maybe….on our skin. These bacteria are collectively known as your microbiota and the mix of bacteria are fairly specific to you, your size, your diet, where you live, your pet – yes really! Your immune system runs surveillance on your microbiota continually; that’s why the bacteria live with you and don’t kill you. And many do indeed help you in more ways than you can imagine (see: https://www.the-scientist.com/?articles.view/articleNo/40228/title/Microbes-of-the-Skin/)

In general bacteria can cause two general types of disease – infection – the ‘right here/right now’ acute nasty illness - but also a more subtler and often chronic immune mediated disease, when the immune system reacts aberrantly to the bacteria or bacterial products and causes inflammatory processes harming bodily tissues…..all highly relevant to people with immune-mediated gut or skin disease particularly, like Crohn’s Disease or Psoriasis. This is where the microbiota may be relevant to contributing to disease.

As a bone disease sub-specialising Rheumatologist, my interest is on aspects of the gut microbiota and how it triggers the immune system to generate musculoskeletal pains and bone disease. People with Crohn’s disease, particularly those who have had surgery on their gut (which moves and changes their gut microbiota), can attest to the importance of such effects. Basically, there is a gap in current understanding. We know the gut microbiota is relevant and we are beginning to understand the associated changes in the skeleton, but we are missing some understanding in the steps between one thing and the other.

So now we should regard with increasing importance the work of Klara Sjögren and Claes Ohlssen in Gothenburg (https://www.ncbi.nlm.nih.gov/pubmed/29079994) who are beginning to define the steps in how the gut microbiota influences the skeleton (in rodents) and even how to modify the bad influences; and ‘yes’ in case you were wondering, probiotics may be relevant! More hypothesis-generating and experiments needed? Of course – and in time, studies in humans - but the new disciplines of Osteoimmunology and Osteomicrobiology, I think, are here to stay.

Perhaps we should encourage the folk at Micropia and the BBC too, to expand their teaching horizons accordingly! Though admittedly the interactive Kiss-O-Meter at Micropia can, at least, show you how your oral microbiota can change and merge with the microbiota of your ‘special friend’ – well that’s Amsterdam for you.