非酒精性脂肪性肝病患者肠道菌群变化及其与禁食诱导脂肪因子、胰岛素抵抗的相关性研究

发布时间：2018-09-17 18:33

【摘要】：背景：非酒精性脂肪性肝病(non-alcoholic fatty liver disease, NAFLD)是指除乙醇和其他明确的肝损害因素所致的，以弥漫性肝细胞大泡性脂肪变为主要特征的临床病理综合征。根据肝内脂肪变、炎症和纤维化的程度，将NAFLD分为单纯性脂肪肝、脂肪性肝炎、脂肪性肝硬化。 NAFLD的发病机制目前尚未完全明确，目前研究认为NAFLD的发病与胰岛素抵抗、脂代谢异常、脂质过氧化等密切相关。而随着研究的不断深入，有学者认为肠道菌群的改变可以通过直接调控机体脂肪合成与储存相关基因的表达，影响能量吸收和储存，促进肥胖形成和胰岛素抵抗等机制影响能量代谢[1]，参与NAFLD的发生和发展。禁食诱导脂肪因子（fasting-induced adipose factor，Fiaf）基因主要负责编码脂蛋白脂肪酶（lipoprteinlipase，LPL）抑制因子，LPL可以水解在脂蛋白颗粒的甘油三酯，促进脂质沉积。Fiaf正是通过抑制LPL，从而抑制甘油三酯循环。有研究表明在动物体内，Fiaf可被肠道菌群调控，肠杆菌的增加可以抑制Fiaf的表达，使得LPL表达增多，导致脂质沉积，但其具体机制需进一步的研究[2,23]。也有研究表明2型糖尿病患者外周血中Fiaf减少，且与胰岛素抵抗相关[24]。因此，我们就NAFLD患者肠道菌群的变化，及其是否与Fiaf因子、胰岛素抵抗有关进行初步研究。目的：检测NAFLD患者肠道菌群的变化，测定血浆Fiaf因子的水平，分析肠道菌群与Fiaf因子、胰岛素抵抗的相关性，探讨肠道菌群在非NAFLD发生发展中的作用。方法：本研究共收集在我院门诊和体检部经临床、实验室、B超确诊为非酒精性脂肪型肝病患者30例（病例组），在我院门诊体检结果为健康并且愿意接受实验的成年人30例（对照组）。NAFLD诊断标准参照2010年中华医学会肝脏病学分会脂肪肝和酒精性肝病学组制定的非酒精性脂肪性肝病诊疗指南[3]。所有研究对象均除外近期使用肠道微生态制剂、酸奶、使用抗生素等可能影响肠道菌群的制剂。常规测量两组的身高、体重、腹围，计算BMI值。选择肠道菌群中5种具有代表性的细菌进行培养，分别计数病例组和对照组肠道菌群中这5种细菌的数量，用以评价肠道菌群的变化状况。收集所有研究对象清晨空腹抽取的静脉血血清，采用全自动生化分析仪测定血清谷丙转氨酶（ALT）、谷草转氨酶(AST)、总胆固醇（CHOL）、甘油三酯（TG）、低密度脂蛋白（LDL）、空腹血糖（FPG）以及空腹胰岛素（FINS）水平。使用平衡稳态模型的评价法，计算胰岛素抵抗指数（homeostatic model assessment-insulin resistance,HOMA-IR），评估胰岛素抵抗程度。通过RT-PCR方法检测两组血浆中Fiaf的mRNA的表达。根据检测结果，分析肠道菌群数量、Fiaf的含量、HOMA-IR的相关性。结果:1两组肠道菌群数量比较：与对照组相比，NAFLD组变形杆菌和肠球菌数量明显增加（9.20±0.20vs8.73±0.41，7.70±0.55vs7.18±0.36，P＜0.05），双歧杆菌、拟杆菌、乳杆菌数量明显减少（8.89±0.28vs9.16±0.22，7.29±0.36vs7.94±0.15，9.21±0.36vs9.76±0.22，P＜0.05）。2两组年龄、性别、BMI、腹围比较：两组在年龄、性别上差异无意义（P0.05），相比正常对照组，NAFLD组研究对象的腹围、BMI均明显升高（90.5±8.86vs81.67±8.89，27.42±3.14vs24.22±2.37，P＜0.05）。3两组血清学指标比较：与对照组相比，病例组ALT（37.75±29.93vs11.17±1.72）、AST（27.96±18.99vs10.83±1.47）、CHOL（5.17±0.80vs4.44±0.54）、TG（2.16±1.04vs0.94±0.41）水平明显升高，，均P＜0.05；病例组Fiaf水平明显降低（1.21±0.05vs1.26±0.03，P＜0.05），病例组HOMA-IR明显升高（4.91±1.21vs2.86±0.51，P＜0.05）。两组LDL差异无统计学意义。4相关性分析：5种肠道菌群中只有变形杆菌数量与血清FiafmRNA表达水平呈显著性负相关（r=-0.734，P0.01），血浆FiafmRNA表达水平和HOMA-IR呈显著性负相关（r=-0.819，P0.01），变形杆菌数量和HOMA-IR呈正相关（r=0.614，P0.01）。结论：1NAFLD患者存在肠道菌群的失调，表现为双歧杆菌、拟杆菌、乳杆菌减少，变形杆菌、肠球菌增加。2变形杆菌数量与Fiaf因子的表达水平呈显著性负相关，与HOMA-IR呈正相关，而Fiaf因子的表达水平与HOMA-IR呈显著性负相关。3表明在NAFLD的发病过程中，肠道菌群失调可能通过抑制Fiaf因子的表达引起IR，参与NAFLD的发生发展。
[Abstract]:BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a clinicopathological syndrome characterized by diffuse hepatocyte bullous steatosis, which is caused by the removal of ethanol and other definite liver damage factors. Steatohepatitis, fatty liver cirrhosis.
Nowadays, the pathogenesis of NAFLD has not been fully clarified. Current studies suggest that the pathogenesis of NAFLD is closely related to insulin resistance, abnormal lipid metabolism and lipid peroxidation. Receiving and storing, promoting the formation of obesity and insulin resistance and other mechanisms affect energy metabolism, participate in the occurrence and development of NAFLD.
Fasting-induced adipose factor (Fiaf) gene is mainly responsible for encoding lipoprotein lipase (LPL) inhibitors, LPL can hydrolyze triglyceride in lipoprotein particles, promote lipid deposition. Fiaf is by inhibiting LPL, thereby inhibiting the triglyceride cycle. Studies have shown that in animals, Fiaf Enterobacteriaceae can inhibit the expression of Fiaf, increase the expression of LPL and lead to lipid deposition, but the specific mechanism needs further study [2,23]. Some studies have shown that the decrease of Fiaf in peripheral blood of patients with type 2 diabetes mellitus is related to insulin resistance [24]. Whether it is related to Fiaf factor and insulin resistance is preliminarily studied.
Objective: To detect the changes of intestinal flora in patients with NAFLD, determine the level of plasma Fiaf factor, analyze the correlation between intestinal flora and Fiaf factor, insulin resistance, and explore the role of intestinal flora in the development of non-NAFLD.
Methods: A total of 30 cases of non-alcoholic fatty liver disease (case group) diagnosed by clinical, laboratory and B-mode ultrasound were collected in the outpatient and physical examination department of our hospital. 30 healthy adults (control group) were willing to accept the experiment. The diagnostic criteria of NAFLD were referred to fatty liver disease of Chinese Medical Association in 2010. All subjects except those who had recently used intestinal microbial agents, yoghurt, antibiotics and other agents that may affect intestinal flora. The height, weight, abdominal circumference of the two groups were routinely measured and BMI values were calculated. Five representative bacteria were selected from the intestinal flora. The bacteria were cultured and counted to evaluate the changes of intestinal flora in the case group and the control group. The venous blood serum was collected from all the subjects on an empty stomach in the morning. The serum ALT, AST, CHOL, glycerol were measured by automatic biochemical analyzer. Levels of triglyceride (TG), low density lipoprotein (LDL), fasting blood glucose (FPG) and fasting insulin (FINS) were measured. Home ostatic model assessment-insulin resistance (HOMA-IR) was used to evaluate insulin resistance. The expression of Fiaf mRNA in plasma was detected by RT-PCR. According to the test results, the number of intestinal flora, the content of Fiaf and the correlation of HOMA-IR were analyzed.
Results: 1. The number of intestinal flora in NAFLD group was significantly higher than that in control group (9.20.20 vs 8.73.41, 7.70.55 vs 7.18.36, P < 0.05). The number of bifidobacteria, Bacteroides and Lactobacillus decreased significantly (8.89.28 vs 9.16.22, 7.29.36 vs 7.94.15, 9.21.36 vs 9.76.22, P < 0.05). Age, sex, BMI, abdominal circumference: There was no significant difference in age and sex between the two groups (P 0.05). Compared with the normal control group, the abdominal circumference and BMI of the NAFLD group were significantly higher (90.5 The levels of AST, AST, AST, AST, CHOL, CHOL, CHOL, CHOL, CHOL, CHOL, CHOL (5.17 (5.17 (0.80 vs 4.44 (0.44 (0.54), TG (2.16 (1.16 (1.04vs 0.94 (.94 (0.41) 41) were significantly increased (P < 0.05), Fiaflevels in case group were significantly decreased (1.21 ((1.21 (0.0.05vs 1.26 (.03), P < 0.03) and HOMA-IR was significantly increased (4.91 (4.91 (1.91 (1.21 1.21 1.21 1.21 vs 2.21 21.21.21 vs 2.21.86 In the meantime, it is necessary to study the relationship between the two. Analysis: Among the five intestinal flora, only Proteus was negatively correlated with serum Fiaf mRNA expression (r = - 0.734, P 0.01), plasma Fiaf mRNA expression was negatively correlated with HOMA-IR (r = - 0.819, P 0.01), and the number of Proteus was positively correlated with HOMA-IR (r = 0.614, P 0.01).
CONCLUSION: 1. The intestinal flora of NAFLD patients is imbalance, showing bifidobacterium, bacteroides, Lactobacillus decrease, Proteus and Enterococcus increase. 2. The number of Proteus is negatively correlated with the expression level of Fiaf factor, and positively correlated with HOMA-IR, while the expression level of Fiaf factor is negatively correlated with HOMA-IR. During the course of disease, intestinal flora disorder may induce IR by inhibiting the expression of Fiaf factor and participate in the occurrence and development of NAFLD.
【学位授予单位】：河北医科大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R575.5

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