EXPERT OPINION
Meet the Expert : IBD Julian Panés
Julian Panés MD is Professor of Medicine and the former Chief of the Department of Gastroenterology at Hospital Clinic de Barcelona and Head of the inflammatory bowel disease unit at the hospital . He spoke to Hospital Pharmacy Europe about inflammatory bowel disease and its impact , its management , and the findings of the recent VEGA study .
Q Please tell us about your institution and its work
A Dr Panés described how he has devoted his career to gastroenterology and that his department aims to provide holistic care to patients with inflammatory bowel disease ( IBD ). The hospital is also an academic centre and together with a scientific team , he is active in translational research studies , focusing on both molecular targets and biomarkers to improve disease monitoring and to develop predictors of response to therapies in IBD .
Q Can you explain what is meant by IBD ?
A As Dr Panés explained , IBD comprises two main conditions : Crohn ’ s disease ; and ulcerative colitis . He added that ‘ both have a genetic predisposition , which has contributed to our understanding of the disease .’ The disease itself is polygenic and there have been over 200 genes already identified as predisposing to IBD . While most of us carry some of these genes , ‘ the median number of genes carried by those with IBD is around 50 compared with 42 in the general population .’ Monogenic forms that manifest as very early onset and severe disease have also been identified .
This genetic predisposition , coupled with exposure to environmental factors , interact with the gut microbiome to orchestrate ‘ an aberrant immune response that leads to the development of inflammation in the intestine .’ The underlying cause of IBD remains unclear and unravelling the nature of the genetic – environmental – microbiome interaction is both challenging and puzzling . For instance , as he explained : ‘ we know that smoking is clearly a predisposing factor in Crohn ’ s disease but it is a protective factor for ulcerative colitis .’ This difference , he said , has been revealed in studies of genetically identical twins , noting how if one sibling is a smoker , they develop Crohn ’ s whereas the non-smoker succumbs to ulcerative colitis .
Once the disease is initiated it becomes chronic and is characterised by periods of exacerbation or flares and periods of
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The prevalence of IBD appears to be on the increase at both ends of the age spectrum
remission . However , as Dr Panés continued , ‘ there is a broad spectrum of disease course over time ; some patients have few flares but at the other extreme , some patients have continuous inflammation .’
Q What are the main clinical differences between ulcerative colitis and Crohn ’ s disease ?
A Dr Panés explained how ulcerative colitis is restricted to the colon , affecting the mucosal layer but disease only extending to the submucosa in severe cases . In contrast , Crohn ’ s disease can occur along any part of the gastrointestinal tract , although it typically affects the ileum and the colon . In addition , Crohn ’ s disease is transmural ; in other words , it is present in all layers of the gut , which probably explains how it is also associated with deep ulceration that completely extends through the colon , forming fistulas or channels between other areas of the intestine or even the skin .
Q What is the role of diet in IBD ?
A Much of the epidemiological evidence points to a role for diet and lifestyle factors as important and potential triggers for the development of IBD . For some unknown reason , IBD is much more prevalent in developed countries . Moreover , this higher prevalence is not simply due to poor reporting or under-diagnosing within less welldeveloped countries because , as such countries become more advanced , there is a commensurate increase in the risk of developing IBD . Dr Panés mentioned how the Mediterranean diet appeared to be protective against the development of IBD and that specific dietary factors , such as a high fat content and intake of emulsifiers , have become recognised risk factors for the disease , as has exposure to antibiotics during the early stages of life . Although a Mediterranean diet appears protective , Dr Panés described how the value of adopting of such a diet once the disease becomes established is less clear and the current evidence is equivocal . Nevertheless , he explained that any potential benefits to following a Mediterranean diet are really only