异基因造血干细胞移植对白血病患儿肠道菌群代谢产物的影响的初步研究

Effect of allogeneic hematopoietic stem cell transplantation on intestinal microflora metabolism in children with leukemia

目的测定异基因造血干细胞移植(allo-HSCT)的白血病患儿粪便中肠道菌群的代谢产物短链脂肪酸(SCFA)水平并研究其意义。方法选取2017年1月—2017年12月在苏州大学附属儿童医院血液科行allo-HSCT的15例白血病患儿,收集并处理四个时期的粪便标本,预处理前期(T1期)、移植后粒细胞缺乏期(T2期)、粒细胞植入期(T3期)和发生肠道急性移植物抗宿主病(GI-aGVHD,简称肠排)期(T4期)。对照组为12例健康儿童。标本接种于含有4种低聚糖培养基(低聚甘露糖MOS、低聚果糖FOS、菊粉INU、木糖醇XYI)和不含任何碳水化合物的对照培养基(YCFA)中发酵24h,通过气相色谱仪检测粪便中以及寡糖发酵后的短链脂肪酸(SCFA)含量。结果未发酵的粪便中主要SCFA在HSCT患儿T1期与正常儿童之间差异无显著性(P>0.05),在HSCT患儿4个时期之间差异无显著性(P>0.05)。经MOS、INU培养基发酵后,T1期总酸、乙酸、丙酸含量明显高于T2期(P<0.05)。经FOS培养基发酵后,T1期乙酸低于正常儿童(P<0.05)。在4个时期,XYI培养基中乙酸、丙酸、丁酸的含量与YCFA培养基比较,差异均无显著性(P>0.05)。结论HSCT患儿肠道菌群可利用不同的低聚糖产生更多的SCFA,提示粪便中的菌群存在活性。测定粪便及低聚糖体外发酵模型中的SCFA可能有助于评估HSCT患儿肠道菌群的紊乱程度,指导临床通过调整膳食结构产生更多有益的SCFA。

Objective To determine the level of fecal short-chain fatty acids(SCFA)of intestinal flora associated metabolites in children with leukemia after allogeneic hematopoietic stem cell transplantation(allo-HSCT)and study its clinical significance.Methods We conducted a study in 15 patients with leukemia who undergoing allo-HSCT in hematology department,Children′s Hospital of Suzhou University from June 2017 to December 2017.Fresh stool specimens were collected at 4 time points from 15 individuals:before pretreatment(T1),during agranulocytosis after transplant(T2),granulocyte engraftment after transplant(T3)and experiencing GI-aGVHD(T4).The control group included 12 healthy children.The concentration of main SCFA in feces was detected.The fresh stool specimens were inoculated into a medium containing 4 oligosaccharides(MOS oligosaccharides,FOS oligosaccharides,inulin INU and xylitol XYI)and a control medium without any carbohydrates(YCFA),the SCFA concentration were detected by gas chromatograph after 24h fermentation.Results The difference in the level of SCFA in unfermented feces at T1 between patients undergoing allo-HSCT and healthy children was not statistically significant(P>0.05).And the differences were not statistically significant in the level of SCFA in feces at T1,T2,T3 and T4(P>0.05).Fermentation of MOS and INU,total acid,acetic acid and propionic acid in T1 were all significantly higher than those in T2(P<0.05);Fermentation of FOS,the level of acetic acid in T1 of patients was significantly lower than that of healthy children(P<0.05).There was no significant difference in acetic acid,propionic acid and butyric acid production among the 4 periods between fermentation of XYI and YCFA(P>0.05);Conclusions The intestinal microbiota of children with leukemia undergoing allo-HSCT can use oligosaccharides to produce more SCFA,suggesting that the bacteria in the feces were alive.The determination of SCFA level in the feces and in vitro fermentation model of oligosaccharides may be helpful to evaluate the degree of intestinal microbiota disturbance in children with leukemia undergoing allo-HSCT,and may enable pediatrician to intelligently adjust the dietary structure of children with leukemia undergoing allo-HSCT to produce more beneficial SCFA.