O'Keefe Stephen J D, Ou Junhai, Delany James P, Curry Scott, Zoetendal Erwin, Gaskins H Rex, Gunn Scott
Division of Gastroenterology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA.
World J Gastrointest Pathophysiol. 2011 Dec 15;2(6):138-45. doi: 10.4291/wjgp.v2.i6.138.
To determine tolerance to fiber supplementation of semi-elemental tube feeds in critically ill patients and measure its effect on colonic microbiota and fermentation.
Thirteen intensive care unit patients receiving jejunal feeding with a semi-elemental diet for predominantly necrotizing pancreatitis were studied. The study was divided into 2 parts: first, short-term (3-9 d) clinical tolerance and colonic fermentation as assessed by fecal short chain fatty acid (SCFA) concentrations and breath hydrogen and methane was measured in response to progressive fiber supplementation increasing from 4 g tid up to normal requirement levels of 8 g tid; second, 4 patients with diarrhea were studied for 2-5 wk with maximal supplementation to additionally assess its influence on fecal microbiota quantitated by quantitative polymerase chain reaction (qPCR) of microbial 16S rRNA genes and Human Intestinal Tract Chip (HITChip) microarray analysis. Nearly all patients were receiving antibiotics (10/13) and acid suppressants (11/13) at some stage during the studies.
In group 1, tolerance to progressive fiber supplementation was good with breath hydrogen and methane evidence (P = 0.008 and P < 0.0001, respectively) of increased fermentation with no exacerbation of abdominal symptoms and resolution of diarrhea in 2 of 4 patients. In group 2 before supplementation, fecal microbiota mass and their metabolites, SCFA, were dramatically lower in patients compared to healthy volunteers. From qPCR and HITChip analyses we calculated that there was a 97% reduction in the predominant potential butyrate producers and starch degraders. Following 2-5 wk of fiber supplementation there was a significant increase in fecal SCFA (acetate 28.4 ± 4.1 μmol/g to 42.5 ± 3.1 μmol/g dry weight, P = 0.01; propionate 1.6 ± 0.5 vs 6.22 ± 1.1, P = 0.006 and butyrate 2.5 ± 0.6 vs 5.9 ± 1.1, P = 0.04) and microbial counts of specific butyrate producers, with resolution of diarrhea in 3 of 4 patients.
Conventional management of critically ill patients, which includes the use of elemental diets and broad-spectrum antibiotics, was associated with gross suppression of the colonic microbiota and their production of essential colonic fuels, i.e., SCFA. Our investigations show that fiber supplementation of the feeds has the potential to improve microbiota mass and function, thereby reducing the risks of diarrhea due to dysbiosis.
确定重症患者对半要素管饲补充纤维的耐受性，并测量其对结肠微生物群和发酵的影响。
对13例因坏死性胰腺炎主要接受空肠半要素饮食喂养的重症监护病房患者进行研究。该研究分为两部分：第一，短期（3 - 9天）临床耐受性及结肠发酵情况，通过粪便短链脂肪酸（SCFA）浓度、呼气氢气和甲烷来评估，以响应纤维补充量从每日三次每次4克逐渐增加至每日三次每次8克的正常需求水平；第二，对4例腹泻患者进行2 - 5周的最大量补充研究，以额外评估其对通过微生物16S rRNA基因定量聚合酶链反应（qPCR）和人类肠道芯片（HITChip）微阵列分析定量的粪便微生物群的影响。在研究的某些阶段，几乎所有患者（10/13）都在接受抗生素治疗，11/13的患者在接受抑酸剂治疗。
在第一组中，对半要素管饲逐渐增加纤维补充的耐受性良好，呼气氢气和甲烷显示发酵增加（分别为P = 0.008和P < 0.0001），4例患者中有2例腹部症状未加重且腹泻缓解。在第二组补充前，与健康志愿者相比，患者粪便微生物群数量及其代谢产物SCFA显著降低。通过qPCR和HITChip分析，我们计算出主要的潜在丁酸盐产生菌和淀粉降解菌减少了97%。在补充纤维2 - 5周后，粪便SCFA显著增加（乙酸盐从28.4 ± 4.1 μmol/g干重增加至42.5 ± 3.1 μmol/g干重，P = 0.01；丙酸盐从1.6 ± 0.5增加至6.22 ± 1.1，P = 0.006；丁酸盐从2.5 ± 0.6增加至5.9 ± 1.1，P = 0.04），特定丁酸盐产生菌的微生物数量增加，4例患者中有3例腹泻缓解。
重症患者的传统管理方法，包括使用要素饮食和广谱抗生素，与结肠微生物群及其必需的结肠燃料即SCFA的产生受到严重抑制有关。我们的研究表明，在管饲中补充纤维有可能改善微生物群数量和功能，从而降低因生态失调导致腹泻的风险。
