Ohashi Kazuo, Kay Mark A, Yokoyama Takashi, Kuge Hiroyuki, Kanehiro Hiromichi, Hisanaga Michiyoshi, Ko Saiho, Nakajima Yoshiyuki
Department of Surgery, Nara Medical University, Kashihara, Japan.
Cell Transplant. 2005;14(9):621-7. doi: 10.3727/000000005783982620.
Liver tissue engineering using hepatocyte transplantation has been proposed as a therapeutic alternative to liver transplantation toward several liver diseases. We have previously reported that stable liver tissue with the potential for liver regeneration can be engineered at extrahepatic sites by transplanting mature hepatocytes into an extracellular matrix. The present study was aimed at assessing the liver tissue persistence after induced regeneration by hepatectomy and repeat regeneration potential induced by repeat hepatectomy. Mouse isolated hepatocytes mixed in EHS extracellular matrix gel were transplanted under both kidney capsules of isogenic mice. The hepatocyte survival persisted for over 25 weeks. In some of the mice, we confirmed that the grafted hepatocytes developed a thin layer of liver tissues under the kidney capsule, determined by specific characteristics of differentiated hepatocytes in cord structures between the capillaries. We then assessed the regenerative potential and persistence of the exogenous liver tissue. To induce liver regeneration, we performed a two-thirds hepatectomy at 70 days after hepatocyte transplantation. Three weeks after this procedure, the engineered liver tissues showed active regeneration, reaching serum marker protein levels of 261 +/- 42% of the prehepatectomy level. We found that the regenerated liver tissue was stably maintained for 100 days (length of the experiment). Repeat regeneration potential was established by performing a repeat hepatectomy (that had been two-thirds hepatectomized at day 70) 60 days after the initial hepatectomy. Again, the regenerated engineered liver tissues showed active regeneration as there was an approximately twofold increase in the serum marker protein levels. The present studies demonstrate that liver tissue, which was recognized as a part of the host naive liver in terms of the regeneration profile, could be engineered at a heterologous site that does not have access to the portal circulation.
利用肝细胞移植的肝脏组织工程已被提议作为肝移植治疗多种肝脏疾病的替代疗法。我们之前曾报道，通过将成熟肝细胞移植到细胞外基质中，可在肝外部位构建具有肝脏再生潜力的稳定肝脏组织。本研究旨在评估肝切除诱导再生后肝脏组织的持久性以及重复肝切除诱导的重复再生潜力。将混合在EHS细胞外基质凝胶中的小鼠分离肝细胞移植到同基因小鼠的双侧肾包膜下。肝细胞存活持续超过25周。在一些小鼠中，我们通过毛细血管间索状结构中分化肝细胞的特定特征确定，移植的肝细胞在肾包膜下形成了一层薄的肝脏组织。然后我们评估了外源肝脏组织的再生潜力和持久性。为诱导肝脏再生，我们在肝细胞移植后70天进行了三分之二肝切除术。该手术后三周，工程化肝脏组织显示出活跃的再生，血清标志物蛋白水平达到肝切除术前水平的261±42%。我们发现再生的肝脏组织稳定维持了100天（实验时长）。通过在初次肝切除术后60天对（在第70天已进行三分之二肝切除的）小鼠进行重复肝切除术来确定重复再生潜力。同样，再生的工程化肝脏组织再次显示出活跃的再生，血清标志物蛋白水平增加了约两倍。本研究表明，就再生情况而言被视为宿主天然肝脏一部分的肝脏组织，可在无法进入门静脉循环的异源部位构建。
