Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

<jats:title>Abstract</jats:title> <jats:sec> <jats:title>Background</jats:title> <jats:p>Due to common evolutionary origins, mitochondrial DNA (mtDNA) shares many similarities with immunogenic bacterial DNA. MtDNA is recognized as a pro-inflammatory damage-associated molecular pattern (DAMP) with a pathogenic role in several inflammatory diseases. We hypothesised that mtDNA is released during active disease, serving as a key pro-inflammatory factor in inflammatory bowel disease (IBD).</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>Between 2014 and 2015, we collected plasma separated within 2 hours of sampling from 97 prospectively recruited IBD patients (67 ulcerative colitis [UC] and 30 Crohn’s disease [CD]) and 40 non-IBD controls. We measured circulating mtDNA using quantitative polymerase chain reaction (amplifying mitochondria COXIII/ND2 genes) and also in mouse colitis induced by dextran sulfate-sodium (DSS). We used a mass spectometry approach to detect free plasma mitochondrial formylated peptides. Furthermore, we examined for mitochondrial damage using electron microscopy (EM) and TLR9 expression, the target for mtDNA, in human intestinal IBD mucosa.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Plasma mtDNA levels were increased in UC and CD (both P &amp;lt; 0.0001) compared with non-IBD controls. These levels were significantly correlated to blood (C-reactive protein, albumin, white cell count), clinical and endoscopic markers of severity, and disease activity. In active UC, we identified 5 mitochondrial formylated peptides (the most abundant being fMMYALF with known chemoattractant function) in plasma. We observed mitochondrial damage in inflamed UC mucosa and significantly higher fecal MtDNA levels (vs non-IBD controls [P &amp;lt; 0.0001]), which supports gut mucosal mitochondrial DAMP release as the primary source. In parallel, plasma mtDNA levels increased during induction of acute DSS colitis and were associated with more severe colitis (P &amp;lt; 0.05). In active IBD, TLR9+ lamina propria inflammatory cells were significantly higher in UC and CD compared with controls (P &amp;lt; 0.05).</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>We present the first evidence to show that mtDNA is released during active IBD. MtDNA is a potential mechanistic biomarker, and our data point to mtDNA-TLR9 as a therapeutic target in IBD.</jats:p> </jats:sec>

Original publication

DOI

10.1093/ibd/izy095

Type

Journal article

Journal

Inflammatory Bowel Diseases

Publisher

Oxford University Press (OUP)

Publication Date

15/09/2018

Volume

24

Pages

2113 - 2122