Aoki Takeshi, Umehara Yutaka, Ferraresso Chiara, Sugiyama Nozomu, Middleton Yvette, Avital Itzhak, Inderbitzin Daniel, Demetriou Achilles A, Rozga Jacek
Department of Surgery, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, CA 90048, USA.
Cell Transplant. 2002;11(6):553-61.
Cell therapy is likely to succeed clinically if cells survive at the transplantation site and are protected against immune rejection. We hypothesized that this could be achieved with intrasplenic transplantation of encapsulated cells because the cells would have instant access to oxygen and nutrients while being separated from the host immune system. In order to provide proof of the concept, primary rat hepatocytes and human hepatoblastoma-derived HepG2 cells were used as model cells. Rat hepatocytes were encapsulated in 100-kDa hollow fibers and cultured for up to 28 days. Rat spleens were implanted with hollow fibers that were either empty or contained I x 10(7) rat hepatocytes. Human HepG2 cells were encapsulated using alginate/ poly-L-lysine (ALP) and also transplanted into the spleen; control rats were transplanted with free HepG2 cells. Blood human albumin levels were measured using Western blotting and spleen sections were immunostained for albumin. Hepatocytes in monolayer cultures remained viable for only 6-10 days, whereas the cells cultured in hollow fibers remained viable and produced albumin throughout the study period. Allogeneic hepatocytes transplanted in hollow fibers remained viable for 4 weeks (end of study). Free HepG2 transplants lost viability and function after 7 days, whereas encapsulated HepG2 cells remained viable and secreted human albumin at all time points studied. ALP capsules, with or without xenogeneic HepG2 cells, produced no local fibrotic response. These data indicate that intrasplenic transplantation of encapsulated cells results in excellent survival and function of the transplanted cells and that the proposed technique has the potential to allow transplantation of allo- and xenogeneic cells (e.g., pancreatic islets) without immunosuppression.
如果细胞在移植部位存活并免受免疫排斥，细胞疗法在临床上就有可能取得成功。我们推测，通过脾内移植封装细胞可以实现这一点，因为这些细胞在与宿主免疫系统隔离的同时能够立即获取氧气和营养物质。为了提供概念验证，将原代大鼠肝细胞和人肝母细胞瘤来源的HepG2细胞用作模型细胞。将大鼠肝细胞封装在100 kDa的中空纤维中并培养长达28天。将中空纤维植入大鼠脾脏，中空纤维要么是空的，要么含有1×10⁷个大鼠肝细胞。使用藻酸盐/聚-L-赖氨酸（ALP）封装人HepG2细胞，并将其也移植到脾脏中；对照大鼠移植游离的HepG2细胞。使用蛋白质印迹法测量血液中人白蛋白水平，对脾脏切片进行白蛋白免疫染色。单层培养的肝细胞仅存活6 - 10天，而在中空纤维中培养的细胞在整个研究期间保持存活并产生白蛋白。移植在中空纤维中的同种异体肝细胞存活了4周（研究结束时）。游离的HepG2移植在7天后失去活力和功能，而封装的HepG2细胞在所有研究时间点都保持存活并分泌人白蛋白。含有或不含有异种HepG2细胞的ALP胶囊均未产生局部纤维化反应。这些数据表明，脾内移植封装细胞可使移植细胞具有出色的存活率和功能，并且所提出的技术有可能允许在不进行免疫抑制的情况下移植同种异体和异种细胞（例如胰岛）。
