研究背景 目前，慢性乙型病毒性肝炎仍为一个影响广泛的全球难题。据世界卫生组织报道，超过2.4亿人生活在乙型肝炎病毒慢性感染的阴影之下，而中国，是乙肝表面抗原检出阳性人口数量最多的国家之一。慢性病毒感染引起的反复或持续性肝脏炎症，可导致严重的并发症如肝硬化、肝功能衰竭及肝细胞癌。 针对慢性乙型病毒性肝炎患者，目前推荐的治疗方式包括口服核苷(酸)类似物及干扰素疗法.目前已有多项研究表明，在接受口服核苷(酸)类药物的慢性乙型肝炎患者中，谷丙转氨酶、干扰素诱导蛋白-10、乙肝表面抗原、乙肝核心抗体都对这种疗法的治疗效果有一定的预测作用。然而，病毒感染后的临床结局，由病毒因素及宿主自身免疫共同介导，而目前已知的大部分预测因子为病毒相关的影响因子，并且，这其中更少有针对高病毒载量的患者的研究。 微小核糖核酸是一类长约22个核苷酸的非编码RNA，在转录后水平调控人体内约三分之一的基因的表达。而微小核糖核酸-122(microRNA-122，miR-122)是哺乳动物肝脏中含量最丰富的一种，并且在其他组织中极少表达。miR-122参与了多项肝脏生理病理活动，在嗜肝病毒感染以及肝细胞癌的发生发展过程都有一定作用。近年来，循环血液中的这类小RNA因其稳定性及方便检测、非侵袭性指标，而被作为潜在生物标志物被广泛研究。血液中的miR-122更是被发现在乙肝相关的肝病中起到生物标志物的作用.而在尚没有肝纤维化证据、也没有发展到肝细胞癌的慢性乙型肝炎患者中，循环血液中的miR-122水平可否预测核苷类药物治疗的治疗应答，还尚不清楚。 研究目的 本研究的目的为探讨血清中的miR-122是否可以作为一个血清学标志物来预测核苷类药物治疗的高病毒载量慢性乙型肝炎患者的治疗应答，并探讨血清miR-122在抗病毒治疗过程中的动态变化。 研究方法 本研究我们共纳入了80例治疗前乙型肝炎e抗原阳性、高病毒载量的、愿意接受核苷(酸)类似物治疗的初治慢性乙型肝炎患者。我们使用了患者在治疗伊始、治疗12周、治疗24周时留存的血清标本，提取了血清中的总RNA，并使用实时荧光定量PCR获得了血清中miR-122的相对定量水平。组间差异分析使用Mann-Whimey U检验或卡方检验。我们使用了受试者工作特征曲线(ROC曲线)以及logistic回归分析来判断血清miR-122对核苷类药物治疗应答的预测价值。血清miR-122的动态变化由重复测量分析进行检验。 研究结果 我们发现，对于治疗96周时能产生病毒学应答的患者，在治疗开始后的早期，即12周及24周，这些患者均表现出较低的血清miR-122水平。而这两个时间点的血清miR-122水平，均能预测患者96周的病毒学应答，曲线下面积分别为0.812和0.749。并且，治疗12周时的低水平血清miR-122，在多因素回归分析中，仍是一个独立的保护因素.另外，我们首次发现了血清miR-122水平在核苷(酸)类药物抗病毒治疗过程中的动态变化，血清miR-122水平呈现出稳定的下降趋势，但在出现病毒学应答的患者群体中，该下降趋势更大。 结论 我们首次定义了核苷(酸)类药物治疗12周时的血清miR-122水平，可以作为独立的预测因子，去预测高病毒载量的慢性乙型肝炎患者的96周病毒学应答。并首次展现了血清miR-122在核苷(酸)类药物抗病毒治疗过程中的动态变化。 关键词：微小核糖核酸-122 慢性乙型病毒性肝炎 病毒学应答 高病毒载量 核苷(酸)类似物

 Background At present, chronic hepatitis B infection still remains an imperative worldwide health problem. According to World Health Organization, over 240 million people worldwide are living with chronic hepatitis B virus (HBV) infection, and China is one of the countries with the highest population of HBsAg-positive individuals. Chronic HBV infection can lead to fatal complications including liver cirrhosis, liver failure, and hepatocellular carcinoma, resulted from repeated flares and continuous inflammation. Currently, antiviral treatment options for chronic hepatitis B (CHB) patients include nucleos(t)ide analogues (NAs) and interferon. Multiple previous studies have identified several predictors for treatment response to NA therapy, such as alanine aminotransferase (ALT) , interferon-inducible protein 10 (IP-10), hepatitis B surface antigen (HBsAg) and hepatitis B core antibody (HBcAb) levels. However, as is known to all that the clinical outcome of virus infection is dependent on a complex interaction between viral factors and host immune response. And yet, most of the current predictors are virus-dependent, moreover, only a handful are performed in CHB patients with high viral load at baseline. MicroRNAs (miRNAs) are a large class of small non-coding RNAs. These approximately 22-nucleotides long RNAs post-transcriptionally regulate one third of human genes. In mammals, microRNA-122 (miR-122) is the most abundant liver-specific miRNA, almost undetectable in other tissues. This miRNA has been identified involved in multiple liver physiology and pathology process. It also plays a role in hepatotropic virus infection as well as occurrence and development of hepatocellular carcinoma. Currently, these small RNAs are increasingly studied in circulating system and are widely identified as potential biomarker because of their stability, easy access to measurement and noninvasive measuring. And miR-122 is also identified to have the ability to serve as a biomarker in HBV-related liver diseases. However, whether the circulating miR-122 has the prognostic value of treatment response to NA therapy in non-neoplastic and non-fibrotic CHB patients remains unknown. Aims The aim of this study was to identify the role of serum miR-122 levels as predictors for treatment response in CHB patients with pre-treatment high viral load treated with NAs. Secondary, we aim to explore the dynamic changes of miR-122 during antiviral treatment. Methods A total of 80 naive CHB patients with pretreatment high viral load and positive hepatitis B e antigen (HBeAg), willing to receive NA therapy, were enrolled in this study. The serum of every patient collected at baseline, week 12 and week 24 were used. The total RNA was isolated and real-time quantitative PCR was performed to obtain relative miR-122 level. Differences between subgroups were analyzed by Mann-Whitney U-test and Chi-squared test. Receiver operating characteristic (ROC) curve and logistic regression were performed to determine the prognostic value of serum miR-122 levels for treatment response to NAs. Dynamic changes in serum miR-122 level were evaluated by repeated measures analysis. Results We found that serum miR-122 levels at the early phase of treatment, like week 12 and week 24, were significantly lower in patients who developed a virological response at week 96, compared with those who did not achieve a virological response. Levels of miR-122 at week 12 and week 24 were determined to be effective prognostic indicators for a VR with satisfactory AUROC values at 0.812 and 0.749 respectively. Moreover, the multivariate analysis also showed that serum miR-122 level at week 12 is still an independent protective factor for virological response. Then we firstly identified the dynamic change of serum miR-122 level during the antiviral treatment with NAs. During the antiviral therapy, serum miR-122 level deceased steadily and an earlier reduction was observed in patients with a virological response. Conclusion We firstly identified serum miR-122 level at week 12 of NA treatment as an independent predictor for the virological response in CHB patients with high viral load. We also firstly identified the dynamic change of serum miR-122 level during the antiviral treatment with NAs. KEYWORDS: MicroRNA-122; Chronic hepatitis B; Virological response; High viral load; Nucleos(t)ide analogues