磁吻合肝脏快速植入对肝移植围手术期肠道免疫微生态的影响

Patients with liver cirrhosis often appear intestinal mucosal barrier damage and intestinal dysbiosis, due to accompanied portal hypertension. It could be aggravated significantly by blocking of the portal vein during liver transplantation, which result in perioperative bacterial translocation and infection. But so far, the effects of the anhepatic phase on the intestinal microflora and immune and their quantitative relationship is unclear. Our group has developed a series of magnetic technologies during past ten years' research work, which could let us implant the donor liver in the acceptor' body rapidly and perform liver transplantation with extremely short anhepatic phase. Based on these finding, we proposed that this technology can achieve "damage control" by implanting the donor liver in acceptor' body rapidly, and thereby alleviate the damage of intestinal mucosa caused the anhepatic phase during liver transplantation, which could improve the perioperative intestinal microecological and systemic immune and inflammation. Therefore, this study will generate a rat model of liver cirrhosis, and explore the impact of the portal vein blocking time on the intestinal immune system and microbial ecosystem during the perioperation, by examining the the changes of intestinal barrier, intestinal immune system and intestinal flora. What' more, we will further study the influence of extremely short anhepatic phase on the intestinal immune system, microbial ecosystem and systemic immune and inflammation by implanting the donor liver into acceptor' body rapidly.

肝硬化患者常因伴随门静脉高压使得肠道粘膜屏障受损及肠道免疫微生态失衡，而行肝移植治疗时无肝期的存在势必将进一步加剧肠粘膜屏障损伤和肠免疫微生态失衡,从而导致围术期细菌移位及感染的发生。但目前无肝期时间对肠免疫微生态的影响及二者的量效关系尚不明确。我们经过近10年的努力，研制出了一系列磁吻合器械，可进行肝脏附属管道的无缝线快速重建，实现超短无肝期的肝移植术。基于此，我们提出：利用该技术可通过供肝快速植入实现肝移植术中的"损伤控制"，有望减轻无肝期造成的肠粘膜屏障损伤，达到改善围术期肠道微生态和全身免疫炎症平衡的目的。为此，本课题拟利用肝硬化大鼠模型，通过检测肠粘膜机械屏障和免疫屏障损伤、肠菌群结构变化、细菌移位等研究肝硬化状态下门脉阻断时间与围术期肠粘膜屏障损伤及肠道免疫微生态失衡之间的量效关系；进一步通过磁吻合快速肝脏植入，研究超短无肝期肝移植改善肠道免疫微生态和全身免疫炎症状态的作用。

肝移植是终末期肝病唯一有效的治疗手段。肝移植术后并发症是影响手术成败和患者预后的重要因素。对肝移植受体而言，由于术前终末期肝病状态、术中无肝期血流阻断、免疫状态改变、术后免疫抑制剂应用等多重因素的存在，使得肠屏障功能较一般患者损伤更重，细菌移位或过度生长的几率更高，而这种错综复杂的菌群改变或又可直接导致机体免疫功能紊乱和全身炎症扩散，诱发或加重移植术后各种并发症的发生。.本研究中通过研制一种磁吻合环，采用磁压榨吻合技术代替缝合法重建肝上下腔静脉，构建标准化磁吻合重建肝上下腔静脉大鼠肝移植模型，实现超短无肝期的肝移植术。并且，通过控制无肝期时间，研究无肝期对于大鼠OLT术后肠道屏障功能及肠道缺血-再灌注损伤的影响。结果显示，大鼠OLT术后肠道屏障功能严重受损，但随着时间推移有恢复的趋势。通过磁吻合技术缩短无肝期，可在一定程度上减轻肠道的缺血再灌注损伤和肠道屏障功能受损程度，减少细菌移位的发生率，抑制肠道紧密连接蛋白的减少，降低肠道屏障通透性的增加程度，降低OLT术后大鼠体内的炎症反应，改善OLT受体的生存情况。.本研究中行 70%肝脏缺血-再灌注胆道损伤造模后的大鼠，对肝脏缺血-再灌注胆道损伤大鼠肠道菌群结构进行研究。动物实验证实， 胆道缺血-再灌注损伤过程伴有肠道菌群多样性下降以及菌群结构改变， 伴随细菌菌群移位率增加，以及 LPS 及相关炎症因子表达升高，说明菌群失调相关炎症反应可能参与或加重了胆道缺血-再灌注损伤。.基于上面研究，通过益生菌干预，研究益生菌对大鼠胆道缺血-再灌注损伤保护作用。结果显示，益生菌预处理能抑制缺血-再灌注过程中致病菌的生长，增强肠屏障功能，降低菌群移位和血清 LPS 水平，并能有效减轻胆道炎症损伤。说明益生菌可能通过抑制缺血-再灌注过程中肠道细菌移位、抑制促炎因子的表达发挥胆道缺血性损伤保护作用。