Russelli Giovanna, Pizzillo Paola, Iannolo Gioacchin, Barbera Floriana, Tuzzolino Fabio, Liotta Rosa, Traina Mario, Vizzini Giovanni, Gridelli Bruno, Badami Ester, Conaldi Pier Giulio
Department of Laboratory Medicine and Advanced Biotechnologies, IRCCS-ISMETT (Istituto Mediterraneo per i Trapianti e Terapie ad alta specializzazione), Palermo, Italy.
Vita-Salute San Raffaele University, Milan, Italy.
PLoS One. 2017 Jul 27;12(7):e0181683. doi: 10.1371/journal.pone.0181683. eCollection 2017.
Hepatitis C virus (HCV) predominantly infects hepatocytes, although it is known that receptors for viral entry are distributed on a wide array of target cells. Chronic HCV infection is indeed characterized by multiple non-liver manifestations, suggesting a more complex HCV tropism extended to extrahepatic tissues and remains to be fully elucidated. In this study, we investigated the gastrointestinal mucosa (GIM) as a potential extrahepatic viral replication site and its contribution to HCV recurrence.
We analyzed GIM biopsies from a cohort of 76 patients, 11 of which were HCV-negative and 65 HCV-positive. Of these, 54 biopsies were from liver-transplanted patients. In 29 cases, we were able to investigate gastrointestinal biopsies from the same patient before and after transplant. To evaluate the presence of HCV, we looked for viral antigens and genome RNA, whilst to assess viral replicative activity, we searched for the replicative intermediate minus-strand RNA. We studied the genetic diversity and the phylogenetic relationship of HCV quasispecies from plasma, liver and gastrointestinal mucosa of HCV-liver-transplanted patients in order to assess HCV compartmentalization and possible contribution of gastrointestinal variants to liver re-infection after transplantation.
Here we show that HCV infects and replicates in the cells of the GIM and that the favorite hosts were mostly enteroendocrine cells. Interestingly, we observed compartmentalization of the HCV quasispecies present in the gastrointestinal mucosa compared to other tissues of the same patient. Moreover, the phylogenetic analysis revealed a high similarity between HCV variants detected in gastrointestinal mucosa and those present in the re-infected graft.
Our results demonstrated that the gastrointestinal mucosa might be considered as an extrahepatic reservoir of HCV and that could contribute to viral recurrence. Moreover, the finding that HCV infects and replicates in neuroendocrine cells opens new perspectives on the role of these cells in the natural history of HCV infection.
丙型肝炎病毒（HCV）主要感染肝细胞，尽管已知病毒进入受体分布在多种靶细胞上。慢性HCV感染的确以多种肝外表现为特征，这表明HCV嗜性更复杂，可扩展到肝外组织，仍有待充分阐明。在本研究中，我们调查了胃肠道黏膜（GIM）作为潜在的肝外病毒复制位点及其对HCV复发的作用。
我们分析了76例患者的GIM活检样本，其中11例HCV阴性，65例HCV阳性。其中，54例活检样本来自肝移植患者。在29例病例中，我们能够调查同一患者移植前后的胃肠道活检样本。为了评估HCV的存在，我们寻找病毒抗原和基因组RNA，同时为了评估病毒复制活性，我们寻找复制中间体负链RNA。我们研究了HCV肝移植患者血浆、肝脏和胃肠道黏膜中HCV准种的遗传多样性和系统发育关系，以评估HCV的区室化以及胃肠道变异体对移植后肝脏再感染的可能作用。
我们在此表明，HCV在GIM细胞中感染并复制，最常见的宿主大多是肠内分泌细胞。有趣的是，与同一患者的其他组织相比，我们观察到胃肠道黏膜中存在的HCV准种存在区室化。此外，系统发育分析显示，在胃肠道黏膜中检测到的HCV变异体与再感染移植物中存在的变异体高度相似。
我们的结果表明，胃肠道黏膜可能被视为HCV的肝外储存库，并且可能导致病毒复发。此外，HCV在神经内分泌细胞中感染并复制这一发现为这些细胞在HCV感染自然史中的作用开辟了新的视角。
