Joseph J M, Goddard M B, Mills J, Padrun V, Zurn A, Zielinski B, Favre J, Gardaz J P, Mosimann F, Sagen J
Division Autonome de Recherche Chirurgicale, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne University, Medical School, Switzerland.
Cell Transplant. 1994 Sep-Oct;3(5):355-64. doi: 10.1177/096368979400300502.
Chromaffin cells have been shown to release a combination of pain-reducing neuroactive compounds including catecholamines and opioid peptides. The allogeneic transplantation of chromaffin cells in the subarachnoid space has been shown to alleviate pain in various rodent models and possibly in terminal cancer patients. Because of the shortage of human cadaver donor tissue, we are investigating the possibility of transplanting xenogeneic cells in polymer capsules. In this technique, cells are surrounded by a permselective synthetic membrane whose pores are suitably sized to allow diffusion of nutrients, neurotransmitters and growth factors, but restrict the diffusion of the large molecules of the immune system and prevent contact with immunocompetent cells. The encapsulation technique therefore allows transplantation of xenogeneic tissue between species as well as retrieval of transplanted cells. Previously we have reported that encapsulated bovine chromaffin cells survive and alleviate pain in various rodent models. The purpose of the present study was to assess the feasibility of implanting a human sized device in a large animal model. Adrenals from 5 calves were surgically removed; chromaffin cells were isolated from these glands using a collagenase-based digestion-filtration technique. Cells were loaded into acrylic-based tubular (5 cm long, 920 microns wide) permselective capsules attached to silicone tethers. The capsules were maintained in vitro for at least 7 days following the encapsulation procedure. Nicotine evoked release was analyzed in a defined subgroup from each batch. One capsule was then implanted using a guiding cannula system in the lumbar subarachnoid space of each sheep for 4 (n = 5) and 8 (n = 1) wk. All capsules were retrieved intact by gentle pulling on the silicone tether. Except for one capsule, the evoked catecholamine release of the retrieved capsules was in the same range as that of other capsules from the same cohort that had been maintained in vitro. All retrieved capsules were devoid of host cell reaction. Clusters of viable cells dispersed in an alginate immobilizing matrix were observed throughout all the implanted capsules. This study demonstrates the feasibility of transplanting functional encapsulated xenogeneic chromaffin cells into the cerebrospinal fluid of a large animal model using a capsule of appropriate dimensions for human implants. We believe that these results suggest the appropriateness of human clinical trials in patients suffering from refractory terminal cancer pain.
嗜铬细胞已被证明能释放多种具有止痛作用的神经活性化合物，包括儿茶酚胺和阿片肽。蛛网膜下腔同种异体移植嗜铬细胞已被证明可缓解多种啮齿动物模型的疼痛，在晚期癌症患者中可能也有此效果。由于人类尸体供体组织短缺，我们正在研究将异种细胞移植到聚合物胶囊中的可能性。在这项技术中，细胞被一种具有选择透过性的合成膜包围，该膜的孔径大小合适，能允许营养物质、神经递质和生长因子扩散，但会限制免疫系统大分子的扩散，并防止与免疫活性细胞接触。因此，这种封装技术允许在不同物种间移植异种组织，也能回收移植的细胞。此前我们报道过，封装的牛嗜铬细胞在多种啮齿动物模型中能存活并缓解疼痛。本研究的目的是评估在大型动物模型中植入人类尺寸装置的可行性。通过手术切除5头小牛的肾上腺；使用基于胶原酶的消化过滤技术从这些腺体中分离出嗜铬细胞。将细胞装入附着有硅胶系带的丙烯酸基管状（长5厘米，宽920微米）选择透过性胶囊中。封装后，胶囊在体外至少维持7天。对每批中的一个特定亚组分析尼古丁诱发的释放情况。然后，使用导向套管系统将一个胶囊植入每只绵羊的腰蛛网膜下腔，分别植入4周（n = 5）和8周（n = 1）。通过轻轻拉动硅胶系带，所有胶囊均完整回收。除了一个胶囊外，回收胶囊诱发的儿茶酚胺释放与同一批次中在体外保存的其他胶囊处于相同范围。所有回收的胶囊均无宿主细胞反应。在所有植入的胶囊中均观察到分散在藻酸盐固定基质中的活细胞簇。这项研究证明了使用适合人类植入的尺寸的胶囊，将功能性封装的异种嗜铬细胞移植到大型动物模型的脑脊液中的可行性。我们认为，这些结果表明对患有难治性晚期癌症疼痛的患者进行人体临床试验是合适的。
