肠道菌群失调与高血压相关

Yang etal. Hypertension (2015)

DOI 10.1161/HYPERTENSIONAHA.115.05315

肠道菌群失调与高血压相关

Gut Dysbiosis Is Linked to Hypertension

Abstract

Emerging evidence suggests that gutmicrobiota is critical in the maintenance of physiological homeostasis. Thisstudy was designed to test the hypothesis that dysbiosis in gut microbiota isassociated with hypertension because genetic, environmental, and dietaryfactors profoundly influence both gut microbiota and blood pressure. BacterialDNA from fecal samples of 2 rat models of hypertension and a small cohort ofpatients was used for bacterial genomic analysis. We observed a significantdecrease in microbial richness, diversity, and evenness in the spontaneouslyhypertensive rat, in addition to an increased Firmicutes/Bacteroidetes ratio.These changes were accompanied by decreases in acetate- and butyrate-producingbacteria. In addition, the microbiota of a small cohort of human hypertensivepatients was found to follow a similar dysbiotic pattern, as it was less richand diverse than that of control subjects. Similar changes in gut microbiotawere observed in the chronic angiotensin II infusion rat model, most notablydecreased microbial richness and an increased Firmicutes/Bacteroidetes ratio.In this model, we evaluated the efficacy of oral minocycline in restoring gutmicrobiota. In addition to attenuating high blood pressure, minocycline wasable to rebalance the dysbiotic hypertension gut microbiota by reducing theFirmicutes/Bacteroidetes ratio. These observations demonstrate that high bloodpressure is associated with gut microbiota dysbiosis, both in animal and humanhypertension. They suggest that dietary intervention to correct gut microbiotacould be an innovative nutritional therapeutic strategy for hypertension.

以往研究显示肠道微生物的变化与慢性炎症疾病有关，如哮喘、急性腹泻、炎症性肠病和感染性疾病。最新证据表明，肠道微生物也可能在心血管疾病和代谢紊乱(如肥胖、糖尿病和代谢综合征)的发展和维持中发挥作用。虽然对健康微生物组成的特征描述还处于初级研究阶段，但越来越多的证据表明，微生物群落厚壁菌门（Firmicutes, F）和拟杆菌门（Bacteroidetes, B）比值的变化，即F/B比值，可以作为某些病理条件的生物标志物。

已有临床研究评估使用益生菌对血压调节的影响。9项随机试验的荟萃分析显示，每天摄入大于109 cfu益生菌的患者的收缩压和舒张压均显著降低。这一证据间接表明，肠道微生物群可能在控制血压平衡中起到关键作用，微生物群组成或失衡的任何变化都可能导致高血压。本研究假设高血压的危险因素，如遗传易感和饮食，会引起肠道微生物群的变化，从而导致血压稳态失衡，控制这种影响可能是治疗这种疾病的一种替代疗法。

研究对象：大鼠模型和来自美国佛罗里达大学健康与心脏病诊所的高血压病人。

受试人群入组条件：

• 年龄大于18岁并已签署知情同意书；

• 排除目前怀孕或已经怀孕六个月的患者；

• 排除2个月内正在接受或接受过抗生素治疗的患者；

• 排除正在使用抗炎性因子、糖皮质激素或其他免疫调节药物的患者；

• 排除服用益生菌的患者；

• 排除有肠道手术史,炎症性肠病,乳糜泻,乳糖不耐症,慢性胰腺炎或其他吸收障碍疾病的患者。

研究方法：

1. 本研究采用两种HTN大鼠模型:一种是8 ~ 10周龄雄性自发性高血压大鼠(SHR)和对照Wistar Kyoto大鼠(WKY)；另一种是8周龄雄性SpragueDawley (SD)大鼠，使用0.9%生理盐水或200ng/kg/min血管紧张素II (Ang II)经皮下植入微型渗透泵(No. 2004 ALZET)慢性灌注 4周。

2. 研究米诺环素对于Ang II诱导的高血压的效果：在植入血管紧张素II (Ang II) 微型渗透泵前，对照组口服1ml无菌水；米诺环素组口服1ml米诺环素（50 mg/kg/day），连续服用4周，采集大鼠粪便样本，-80℃保存。。

3. 人群研究中，受试者被分为对照组(未服用降压药)和高血压组(目前正在接受降压药治疗)，采集粪便样本。

4. 本研究使用了3个常用的参数来研究肠道微生物: Chao丰富度、Pielou均匀度和Shannon多样性。

检测方法：16s rRNA基因V4-V5区测序等。

研究结果：

1.高血压动物模型中微生物丰富度降低，F/B比值显著升高，提示高血压患者存在肠道菌群失调。

2.这种失调与产生醋酸和丁酸盐的细菌数量减少，产生乳酸盐的细菌数量增加有关。

3.在一小群高血压患者中证实肠道菌群失调，提示本研究具有潜在的临床意义。

4.口服米诺环素可使高血压大鼠肠道微生物群再恢复平衡。

5.研究者认为，高血压前期信号(如饮食、遗传易感性、肥胖)影响肠道微生物组成，诱导机体失调，增加骨髓和血液中的炎症细胞以及造血干细胞。造血干细胞的增加与它们向大脑的外渗和神经炎症的建立有关。肠道菌群失调、外周炎症和神经炎症的联合作用导致高血压的发生、建立和维持。

Figure 2. Comparison of microbiotacomposition between Wistar Kyoto (WKY) rats and spontaneously hypertensive rats(SHRs). A, The Firmicutes/Bacteroidetes ratio (F/B ratio) was calculated as abiomarker of gut dysbiosis. B, Phylum breakdown of the 4 most abundantbacterial communities in the WKY rat (n=5) and SHR (n=6) fecal samples. Adecrease of Bacteroidetes along withan increase of Firmicutes resulted ina dysbiosis signature of gut microbiota in SHRs. A significant reduction of the Actinobacteria phylum correlated with alower diversity value. Results were compared by Student t test; **P<0.01 and***P<0.001.

图2. 雄性正常大鼠与自发性高血压大鼠微生物群组成的比较。A，硬杆菌/拟杆菌比率（F/B比率）,肠道发育不良的生物标志物。B，Wky大鼠（n=5）和SHR（n=6）粪便样品中4个最丰富细菌群落的门分解。随着类杆菌数量的减少和硬度的增加，SHR中的肠道微生物群出现了发育不良的特征。放线菌门的显著减少与较低的多样性值相关。结果通过学生t检验进行比较，**p<0.01，**p<0.001。

Figure 4. Reduced microbial richness anddiversity in hypertension patients. A. Lower microbial richness and diversityin hypertension patients. The hypertension patient demonstrated significantlyhigher ambient systolic blood pressure when compared with control. Fecalsamples from hypertension patient were collected and 16S rDNA library wasprepared and analyzed by illumina Miseq sequencer. Richness, evenness, anddiversity were used to evaluate general differences of microbial composition indifferent groups. B. Principal coordinate analysis of control and hypertensiongroups. Weighted uniFrac analyses were performed to calculate the distancesbetween fecal samples from control and hypertension patients. Each axispercentage describes how much variation that one dimension accounts for. Bycomparing the samples in a 3 dimensional PCoA figure, two separate clusterswere formed. Results were compared by student’s t-test; * p<0.05, ***p<0.001. Control=10, Hypertension=7.

图4. 降低高血压患者的微生物丰富度和多样性。a.高血压患者的微生物丰富度和多样性较低。与对照组相比，高血压患者的周围收缩压明显升高。收集高血压患者粪便标本，用Illumina miseq测序仪制作16S rDNA文库，并进行分析。采用丰富度、均匀度和多样性评价不同群体微生物组成的一般差异。b.对照组和高血压组的主坐标分析。采用加权unifrac分析计算对照组和高血压患者粪便样本之间的距离。每个轴百分比描述一个维度所占的变化量。通过比较三维PCOA图中的样品，形成两个独立的簇。结果通过学生t检验进行比较，*p<0.05，*p<0.001。对照组10例，高血压组7例。

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