Rokstad A M, Strand B, Rian K, Steinkjer B, Kulseng B, Skjåk-Braek G, Espevik T
Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
Cell Transplant. 2003;12(4):351-64. doi: 10.3727/000000003108746902.
The use of nonautologous cell lines producing a therapeutic substance encapsulated within alginate microcapsules could be an alternative way of treating different diseases in a cost-effective way. Malignant brain tumors have been proposed to be treated locally using engineered cells secreting proteins with therapeutic potential encapsulated within alginate microcapsules. Optimization of the alginate capsule bioreactors is needed before this treatment can be a reality. Recently, we have demonstrated that alginate-poly-L-lysine microcapsules made with high-G alginate and a gelled core disintegrated as cells proliferated. In this study we examined the growth and endostatin secretion of 293-EBNA (293 endo) cells encapsulated in six different alginate microcapsules made with native high-G alginate or enzymatically tailored alginate. Stability studies using an osmotic pressure test showed that alginate-poly-L-lysine-alginate microcapsules made with enzymatically tailored alginate was mechanically stronger than alginate capsules made with native high-G alginate. Growth studies showed that the proliferation of 293 endo cells was diminished in microcapsules made with enzymatically tailored alginate and gelled in a barium solution. Secretion of endostatin was detected in lower amounts from the enzymatically tailored alginate microcapsules compared with the native alginate microcapsules. The stability of the alginate microcapsules diminished as the 293 endo cells grew inside the capsules, while empty alginate microcapsules remained stable. By using microcapsules made of fluorescenamine-labeled alginate it was clearly visualized that cells perforated the alginate microcapsules as they grew, destroying the alginate network. Soluble fluorescence-labeled alginate was taken up by the 293 endo cells, while alginate was not detected in live spheroids within fluorescence-labeled alginate microcapsules. Despite that increased stability was achieved by using enzymatically tailored alginate, the cell proliferation destroyed the alginate microcapsules with time. It is therefore necessary to use cell lines that have properties more suited for alginate encapsulation before this technology can be used for therapy.
使用产生封装在藻酸盐微胶囊内治疗物质的非自体细胞系可能是以具有成本效益的方式治疗不同疾病的一种替代方法。有人提出使用分泌具有治疗潜力蛋白质的工程细胞封装在藻酸盐微胶囊内对恶性脑肿瘤进行局部治疗。在这种治疗成为现实之前，需要对藻酸盐胶囊生物反应器进行优化。最近，我们已经证明，用高G藻酸盐制成的藻酸盐-聚-L-赖氨酸微胶囊和凝胶化核心在细胞增殖时会解体。在本研究中，我们检测了封装在六种不同藻酸盐微胶囊中的293-EBNA（293内抑素）细胞的生长和内皮抑素分泌情况，这些微胶囊由天然高G藻酸盐或酶法定制藻酸盐制成。使用渗透压测试进行的稳定性研究表明，用酶法定制藻酸盐制成的藻酸盐-聚-L-赖氨酸-藻酸盐微胶囊在机械性能上比用天然高G藻酸盐制成的藻酸盐微胶囊更强。生长研究表明，在酶法定制藻酸盐制成并在钡溶液中凝胶化的微胶囊中，293内抑素细胞的增殖减少。与天然藻酸盐微胶囊相比，酶法定制藻酸盐微胶囊中检测到的内皮抑素分泌量较低。随着293内抑素细胞在胶囊内生长，藻酸盐微胶囊的稳定性降低，而空的藻酸盐微胶囊保持稳定。通过使用由荧光胺标记藻酸盐制成的微胶囊，可以清楚地看到细胞在生长时穿透了藻酸盐微胶囊，破坏了藻酸盐网络。可溶性荧光标记藻酸盐被293内抑素细胞摄取，而在荧光标记藻酸盐微胶囊内的活球体中未检测到藻酸盐。尽管使用酶法定制藻酸盐实现了稳定性的提高，但随着时间的推移，细胞增殖破坏了藻酸盐微胶囊。因此，在这项技术可用于治疗之前，有必要使用更适合藻酸盐封装的细胞系。
