Characterising IBS subtypes and their response to Stress using MRI

肠易激综合征（IBS）是一种非常常见的疾病，会导致反复腹痛和不稳定的排便习惯。虽然不是致命的，但它可以显着降低患者的生活质量。IBS患者报告了一系列令人困惑的肠道习惯紊乱，包括腹泻和便秘，有时在同一个病人身上。患者报告的症状是主观的，其意义是不确定的，没有一个可靠的方法来测量肠功能。超过一半的IBS患者异常焦虑，三分之二的人认为他们的症状与压力有关，这可能解释了排便习惯的日常变化。然而，很难客观地确定压力对任何个体患者的影响。我们最近开发并验证了一种新的非侵入性磁共振成像（MRI）技术，用于对小肠和结肠功能进行成像。我们相信，这可能是一个方便的测试，成本低于许多目前使用的测试，客观地评估IBS患者和量化他们对压力的反应。我们认为，压力通过释放一种叫做CRF的化学物质作用于胃肠道系统，CRF通过神经系统和肠道中称为肥大细胞的特殊细胞起作用。这会刺激收缩并加速肠道运动。我们最近表明，MRI可以检测CRF对小肠的影响，其水含量在注射后30分钟内减少了1/3。以前的研究表明，CRF也刺激结肠收缩。我们的目标是开发经济有效地分析结肠图像的新方法，以补充我们研究小肠含水量和肠道运动速率的方法。我们将检测不同亚型IBS患者的小肠和结肠水含量和转运率，并评估结肠粘膜中的肥大细胞。然后，我们将通过检查MRI参数、肥大细胞活化和应激心理标志物之间的相关性来验证我们的假设，即IBS患者的肠道及其肥大细胞对应激更敏感。我们的研究将有助于更好地了解肠易激综合征患者的肠道功能异常和应激的影响。它们还可能提供预测个体对不同治疗的反应的新方法。

Irritable Bowel Syndrome (IBS) is an extremely common condition which causes recurrent abdominal pain and erratic bowel habits. Although not fatal it can markedly reduce the sufferer‘s quality of life. IBS sufferers report a confusing range of disturbances of bowel habit including both diarrhoea and constipation, sometimes in the same patient. Patients reported symptoms are subjective and their significance is uncertain without a reliable way of measuring bowel function. More than half the IBS patients are abnormally anxious and two thirds believe their symptoms are stress related, which may explain the day to day variability in bowel habit. However it is difficult to objectively determine the effect of stress in any individual patient. We have recently developed and validated a new, non-invasive, Magnetic Resonance Imaging (MRI) technique to image small bowel and colon function. We believe that this could be a convenient test, costing less than many currently used tests, to objectively assess IBS patients and quantify their responsiveness to stress. We believe that stress acts on the gastrointestinal system by releasing a chemical, called CRF which acts via the nervous system and special cells in the gut called mast cells. This stimulates contractions and accelerate movements through the bowel. We have recently shown that MRI can detect the effect of CRF on the small bowel whose water content is reduced by 1/3rd within 30 minutes of injection. Previous studies show that CRF also stimulates colonic contractions. We aim to develop new methods of economically and effectively analysing colon images to compliment our method of studying small bowel water content and rates of movement through the gut. We will characterise the small and colonic water content and transit rates in various subtypes of IBS patients in whom we will also assess mast cells in the colonic mucosa. We will then test our hypothesis that the bowel and its mast cells in IBS patients are more sensitive to the stress by examining the correlation between MRI parameters, mast cell activation and psychological markers of stress. Our studies will lead to a better understanding of abnormalities of gut function and the effect of stress in IBS patients. They may also provide novel ways of predicting the response of individuals to different treatments.