Di Stefano Michele, Mengoli Caterina, Bergonzi Manuela, Klersy Catherine, Pagani Elisabetta, Miceli Emanuela, Corazza Gino Roberto
1st Department of Medicine, University of Pavia Foundation IRCCS "S. Matteo" Hospital, Pavia, Italy.
Biometry and Clinical Epidemiology, Foundation IRCCS "S. Matteo" Hospital, Pavia, Italy.
Am J Gastroenterol. 2015 Jun;110(6):891-8. doi: 10.1038/ajg.2015.47. Epub 2015 Mar 24.
The role of colonic methane production in functional bowel disorders is still uncertain. In small samples of irritable bowel syndrome (IBS) patients, it was shown that methane breath excretion correlates with clinical presentation and delayed gastrointestinal transit time. The aim of this study was to evaluate the relationship between intestinal production and breath excretion of CH4 and to correlate CH4 production with the presence and the severity of symptoms, in a large cohort of IBS patients and in a group of healthy volunteers.
A group of 103 IBS patients and a group of 28 healthy volunteers were enrolled. The presence and severity of symptoms and gastrointestinal transit were evaluated in all subjects, who underwent breath H2/CH4 measurement for 7 h after lactulose to identify breath excretors of these gases; H2 and CH4 were also measured in rectal samples to identify colonic producers. Cumulative H2 and CH4 excretion and production were evaluated by the area under the time-concentration curve calculation (AUC).
In IBS patients, CH4 was detected in rectal samples in 48 patients (47%), but only 27 of them (26% of the 103 enrolled patients) excreted this gas with breath. In CH4 producers, the prevalence and severity of symptoms and gastrointestinal transit time were not significantly different with respect to non-producers. IBS subtypes were homogeneously represented in CH4 producers and in non-producers. Healthy volunteers, compared with IBS patients, showed a significantly lower prevalence of CH4 excretion, whereas no difference was found in the prevalence of colonic CH4 production; moreover, in healthy volunteers compared with IBS, CH4 breath excretion and CH4 production were not different in quantitative terms.
Our data show that colonic CH4 production is not associated with clinical presentation in IBS patients and does not correlate with symptom severity or with gastrointestinal transit time. Clinical inferences based on breath CH4 excretion should undergo an in-depth revision, as this method is not a good marker of CH4 colonic production.
结肠甲烷生成在功能性肠病中的作用仍不明确。在小样本的肠易激综合征（IBS）患者中，研究表明甲烷呼气排泄与临床表现及胃肠道转运时间延迟相关。本研究的目的是在一大群IBS患者和一组健康志愿者中，评估CH4的肠道生成与呼气排泄之间的关系，并将CH4生成与症状的存在及严重程度相关联。
招募了103名IBS患者和28名健康志愿者。对所有受试者评估症状的存在及严重程度和胃肠道转运情况，这些受试者在服用乳果糖后进行7小时的呼气H2/CH4测量，以确定这些气体的呼气排泄者；还对直肠样本进行H2和CH4测量，以确定结肠生成者。通过计算时间-浓度曲线下面积（AUC）评估累积H2和CH4排泄及生成情况。
在IBS患者中，48名患者（47%）的直肠样本中检测到CH4，但其中只有27名患者（占103名入组患者的26%）呼气排出这种气体。在CH4生成者中，与非生成者相比症状的患病率和严重程度以及胃肠道转运时间并无显著差异。CH4生成者和非生成者中IBS各亚型的分布均匀。与IBS患者相比，健康志愿者CH4排泄的患病率显著更低，而结肠CH4生成的患病率未发现差异；此外，与IBS患者相比，健康志愿者的CH4呼气排泄和CH4生成在数量上并无差异。
我们的数据表明，IBS患者结肠CH4生成与临床表现无关，且与症状严重程度或胃肠道转运时间无关。基于呼气CH4排泄的临床推断应进行深入修订，因为这种方法并非CH4结肠生成的良好标志物。
