用于测量马口腔至盲肠转运时间的乳糖13C-脲呼吸试验的体外验证
In vitro validation of the lactose 13C-ureide breath test for equine orocaecal transit time measurement.
作者信息
Sutton D G M, Preston T, Love S
机构信息
School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK.
出版信息
Equine Vet J Suppl. 2011 Aug(39):42-8. doi: 10.1111/j.2042-3306.2011.00406.x.
REASONS FOR PERFORMING STUDY
Validation of a reliable, noninvasive clinical test for quantification of equine orocaecal transit time (OCTT) is required. This would facilitate an evidence-based approach to investigation and treatment of equine small intestinal disorders.
OBJECTIVES
- Comparison of the lactose (13) C-ureide breath test (LUBT) with the hydrogen breath test (H(2) BT) for OCTT measurement. 2) Identification of the characteristics of gastrointestinal microbial glycosylureide hydrolase activity in vitro. 3) Production of an optimised protocol for the LUBT for in vivo measurement of equine OCTT.
HYPOTHESIS
Significant lactose (13) C-ureide ((13) C-LU) hydrolase activity is restricted to the large bowel. The rate of expiratory (13) CO(2) production after ingestion of the isotope will provide an indirect quantifiable measure of orocaecal transit rate. Requisite bacterial activity may be enhanced by a primer dose of unlabelled substrate as shown in Man.
METHODS
Combined LUBT and H(2) BT were performed in 8 healthy individuals. Analysis of sequential end expiratory breath samples was used to calculate OCTT and results compared. Digestion of (13) C-LU was investigated in vitro using fresh faecal material or intestinal aliquots collected post mortem. Isotopic fermentation rate was measured by rate of appearance of (13) CO(2) .
RESULTS
Peaks in expiratory (13) CO(2) occurred in all individuals after ingestion of the labelled test meal, whereas H(2) expiration was variable. Both faecal and intestinal microbial digestion of (13) C-LU were maximised by prior exposure to (12) C-LU. Induced bacterial glucoseureide hydrolase activity was significantly greater in the caecum than in the small intestine (n = 10, P<0.05).
CONCLUSIONS
Significant (13) C-LU digestion is restricted to the equine large intestine under normal conditions, and is enhanced by prior exposure to (12) C-LU, making (13) C-LU a suitable noninvasive marker of equine OCTT. The LUBT is more reliable than the H(2) BT for measurement of equine OCTT.
开展本研究的原因
需要验证一种可靠的、非侵入性的临床检测方法，用于定量马的口盲肠转运时间（OCTT）。这将有助于采用循证方法来研究和治疗马的小肠疾病。
目的
1）比较乳糖（13）C-脲呼气试验（LUBT）与氢呼气试验（H₂BT）用于测量OCTT。2）确定体外胃肠道微生物糖基脲水解酶活性的特征。3）制定优化的LUBT方案，用于体内测量马的OCTT。
假设
显著的乳糖（13）C-脲（（13）C-LU）水解酶活性局限于大肠。摄入同位素后呼气（13）CO₂ 的产生速率将提供口盲肠转运速率的间接可量化指标。如在人类研究中所示，未标记底物的引物剂量可增强所需的细菌活性。
方法
对8名健康个体进行联合LUBT和H₂BT。分析连续的终末呼气样本以计算OCTT并比较结果。使用新鲜粪便材料或死后收集的肠等分样本在体外研究（13）C-LU的消化。通过（13）CO₂ 的出现速率测量同位素发酵速率。
结果
摄入标记测试餐之后，所有个体呼气（13）CO₂ 均出现峰值，而H₂ 呼出情况则各不相同。通过预先接触（12）C-LU可使（13）C-LU在粪便和肠道中的微生物消化最大化。诱导的细菌葡萄糖脲水解酶活性在盲肠中显著高于小肠（n = 10，P<0.05）。
结论
在正常情况下，显著的（13）C-LU消化局限于马的大肠，并且预先接触（12）C-LU可增强这种消化，使得（13）C-LU成为马OCTT合适的非侵入性标记物。对于测量马的OCTT，LUBT比H₂BT更可靠。
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