Tomasz Dawiskiba, Jan Skóra, Piotr Barć, Krzysztof Korta, Kornel Pormańczuk, Przemyslaw Szyber, Department of Vascular, General and Transplantation Surgery, Wroclaw Medical University, 50-556 Wroclaw, Poland.
World J Gastroenterol. 2014 Jan 7;20(1):163-74. doi: 10.3748/wjg.v20.i1.163.
To evaluate the utility of serum and urine metabolomic analysis in diagnosing and monitoring of inflammatory bowel diseases (IBD).
Serum and urine samples were collected from 24 patients with ulcerative colitis (UC), 19 patients with the Crohn's disease (CD) and 17 healthy controls. The activity of UC was assessed with the Simple Clinical Colitis Activity Index, while the activity of CD was determined using the Harvey-Bradshaw Index. The analysis of serum and urine samples was performed using proton nuclear magnetic resonance (NMR) spectroscopy. All spectra were exported to Matlab for preprocessing which resulted in two data matrixes for serum and urine. Prior to the chemometric analysis, both data sets were unit variance scaled. The differences in metabolite fingerprints were assessed using partial least-squares-discriminant analysis (PLS-DA). Receiver operating characteristic curves and area under curves were used to evaluate the quality and prediction performance of the obtained PLS-DA models. Metabolites responsible for separation in models were tested using STATISTICA 10 with the Mann-Whitney-Wilcoxon test and the Student's t test (α = 0.05).
The comparison between the group of patients with active IBD and the group with IBD in remission provided good PLS-DA models (P value 0.002 for serum and 0.003 for urine). The metabolites that allowed to distinguish these groups were: N-acetylated compounds and phenylalanine (up-regulated in serum), low-density lipoproteins and very low-density lipoproteins (decreased in serum) as well as glycine (increased in urine) and acetoacetate (decreased in urine). The significant differences in metabolomic profiles were also found between the group of patients with active IBD and healthy control subjects providing the PLS-DA models with a very good separation (P value < 0.001 for serum and 0.003 for urine). The metabolites that were found to be the strongest biomarkers included in this case: leucine, isoleucine, 3-hydroxybutyric acid, N-acetylated compounds, acetoacetate, glycine, phenylalanine and lactate (increased in serum), creatine, dimethyl sulfone, histidine, choline and its derivatives (decreased in serum), as well as citrate, hippurate, trigonelline, taurine, succinate and 2-hydroxyisobutyrate (decreased in urine). No clear separation in PLS-DA models was found between CD and UC patients based on the analysis of serum and urine samples, although one metabolite (formate) in univariate statistical analysis was significantly lower in serum of patients with active CD, and two metabolites (alanine and N-acetylated compounds) were significantly higher in serum of patients with CD when comparing jointly patients in the remission and active phase of the diseases. Contrary to the results obtained from the serum samples, the analysis of urine samples allowed to distinguish patients with IBD in remission from healthy control subjects. The metabolites of importance included in this case up-regulated acetoacetate and down-regulated citrate, hippurate, taurine, succinate, glycine, alanine and formate.
NMR-based metabolomic fingerprinting of serum and urine has the potential to be a useful tool in distinguishing patients with active IBD from those in remission.
评估血清和尿液代谢组学分析在炎症性肠病（IBD）诊断和监测中的应用。
收集 24 例溃疡性结肠炎（UC）患者、19 例克罗恩病（CD）患者和 17 例健康对照者的血清和尿液样本。使用简单临床结肠炎活动指数评估 UC 活动度，使用 Harvey-Bradshaw 指数评估 CD 活动度。采用质子核磁共振（NMR）光谱法分析血清和尿液样本。将所有光谱导出到 Matlab 中进行预处理，得到两个血清和尿液的数据矩阵。在进行化学计量学分析之前，对两个数据集均进行单位方差缩放。采用偏最小二乘判别分析（PLS-DA）评估代谢物指纹图谱的差异。采用接收者操作特征曲线和曲线下面积评估获得的 PLS-DA 模型的质量和预测性能。使用 STATISTICA 10 软件，采用曼-惠特尼-威尔科克森检验和学生 t 检验（α=0.05）检验模型中分离的代谢物。
活动期 IBD 患者与缓解期 IBD 患者之间的比较提供了良好的 PLS-DA 模型（血清 P 值为 0.002，尿液 P 值为 0.003）。能够区分这些组的代谢物为：N-乙酰化化合物和苯丙氨酸（血清中上调）、低密度脂蛋白和极低密度脂蛋白（血清中下调）以及甘氨酸（尿液中上调）和乙酰乙酸（尿液中下调）。在活动期 IBD 患者与健康对照组之间也发现了代谢组学特征的显著差异，为 PLS-DA 模型提供了非常好的分离（血清 P 值<0.001，尿液 P 值<0.001）。在这种情况下，包括的最强生物标志物代谢物为亮氨酸、异亮氨酸、3-羟基丁酸、N-乙酰化化合物、乙酰乙酸、甘氨酸、苯丙氨酸和乳酸（血清中上调）、肌酸、二甲亚砜、组氨酸、胆碱及其衍生物（血清中下调）以及柠檬酸、马尿酸、瓜氨酸、牛磺酸、琥珀酸和 2-羟丁酸（尿液中下调）。尽管在单变量统计分析中有一种代谢物（甲酸盐）在活动期 CD 患者血清中显著降低，两种代谢物（丙氨酸和 N-乙酰化化合物）在比较疾病缓解期和活动期患者时在 CD 患者血清中显著升高，但基于血清样本分析，CD 和 UC 患者之间的 PLS-DA 模型未发现明显分离。与血清样本的结果相反，尿液样本分析能够区分缓解期和健康对照组的 IBD 患者。在此情况下，重要的代谢物包括上调的乙酰乙酸和下调的柠檬酸、马尿酸、牛磺酸、琥珀酸、甘氨酸、丙氨酸和甲酸盐。
基于 NMR 的血清和尿液代谢组学指纹图谱具有区分活动期 IBD 患者与缓解期患者的潜力。
