# Very interesting



## eric (Jul 8, 1999)

From UNC "Digest" with permission.Emeran Mayer, MD, visited the UNCCenter for Functional GI & MotilityDisorders on August 30-31, 2004. Heis Professor of Medicine and Directorof the Center for NeurovisceralSciences & Womenï¿½s Health, DavidGeffen School of Medicine at UCLA,and the following is his report on hisvisit to UNC."During my recent visit at the GI Division at UNC, I had theopportunity to talk with several key investigators at the Centerand to discuss possible research collaborations, in particularin the area of brain imaging. I was impressed by the depthand breadth of research performed at the Center and greatlyenjoyed the interactions with investigators and staff. My visitincluded a presentation to the Division on Gastroenterologyand Hepatology titled ï¿½Progress in IBS Biology: One Diseaseor Many Mechanisms Leading to Similar Symptoms.ï¿½Functional GI disorders, including IBS, are currently defined byGI symptom-based criteria, yet every experienced clinicianis aware of the multiplicity of symptoms and complaints thatmost IBS patients report when asked appropriately. Someof these symptoms may be attributed to other parts of theGI tract (such as heartburn or chest pain) while others mayattributed to other organs (urinary urgency, pelvic pain) orthe skeletomotor system (headaches, muscle and joint pain).To explain such ï¿½co-morbidities,ï¿½ several theories have beenproposed: (1) IBS as defined by the Rome criteria is a diseaseof the intestine, but can co-occur with other syndromes.( 2) The GI tract related symptoms are just one of severalpossible somatic manifestations of disorders that primarilyimpact affect and mood (anxiety and depression). ( 3) IBS isa reflection of an altered perception of so-called homeostaticafferent signals from the GI tract and resulting alteredautonomic responses. In my presentation, I briefly addressedthe following two hypotheses:Is IBS a disease related to inappropriate immune activationof the intestine?Is IBS a somatic manifestation of psychiatric disease?Evidence was reviewed showing that currently availabledata does not support the immune activation hypothesis. Inthe absence of altered perceptual responses to a chronically,mildly inflamed intestine, typical IBS symptoms would be quiteunlikely. Similarly, current evidence does not support that IBSsymptoms only occur in patients with depression or anxiety,and that IBS symptoms in the normal population are generallynot associated with DSM-4 diagnoses. As an alternative, thefollowing hypothesis was proposed:IBS reflects an alteration in the perception of and responseto homeostatic feelings.Recent evidence was reviewed from brain imaging studiessuggesting that IBS patients (similar to fibromyalgia patients)may either fail to activate endogenous pain inhibition systemsor inappropriately activate pain facilitation systems, whichwill result in a central amplification of homeostatic afferentsignals either arising from the GI tract, other viscera, orthe musculoskeletal system. It was speculated that such aninappropriate amplification of homeostatic afferent signalsmight be related symptom-driven fears and to the DSM 4construct of ï¿½somatizationï¿½. Future studies are requiredspecifically test this novel hypothesis."UNC's "Digest" online in PDF format http://www.med.unc.edu/medicine/fgidc/coll...t_winter_04.pdf


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