In vitro and in vivo study of the application of volvox spheres to co-culture vehicles in liver tissue engineering

Publication date: Available online 21 September 2017
Source:Acta Biomaterialia
Author(s): Siou Han Chang, Han Hsiang Huang, Pei Leun Kang, Yu Chian Wu, Ming-Huang Chang, Shyh Ming Kuo
Volvox sphere is a biomimetic concept of a natural Volvox, wherein a large outer sphere contains smaller inner spheres, which can encapsulate cells and provide a double-layer three-dimensional environment for culturing cells. This study simultaneously encapsulated rat mesenchymal stem cells (MSCs) and AML12 hepatocytes in volvox spheres and extensively evaluated the effects of various culturing modes on cell functions and fates. The results showed that compared with a static flask culture, MSCs encapsulated in volvox spheres differentiated into hepatocyte-like cells with a 2-fold increase in albumin (ALB) expression and a 2.5-fold increase in cytokeratin 18 expression in a dynamic bioreactor. Moreover, the restorative effects of volvox spheres encapsulating cells on retrorsine-exposed CCl4-induced liver injuries in rats were evaluated. The data presented significant reductions in AST and ALT levels after the implantation of volvox spheres encapsulating both MSCs and AML12 hepatocytes in vivo. In contrast to the negative control group, histopathological analysis demonstrated liver repair and formation of the new liver tissue in groups implanted with volvox spheres containing cells. These results demonstrate that liver cells implanted with volvox spheres encapsulating both MSCs and AML12 hepatocytes promote liver repair and liver tissue regeneration in liver failure caused by necrotizing agents such as retrorsine and CCl4. Hence, volvox spheres encapsulating MSCs and liver cells can be a promising and clinically effective therapy for liver injury.Statement of SignificanceIn this study, we have utilized used a Vvolvox sphere, which is a unique design to thatmimics the natural vVolvox,that consists of a large outer-sphere that contains smaller inner-spheres, which provide a three-dimensional environment to culture cells. The purpose of this study is to co-culture mesenchymal stem cells(MSCs) and AML12 liver cells in Vvolvox spheres and to evaluate the two different culture methods, dynamic bioreactor and static culture flask,on the cultured cells.AndalsoIn addition, we aimed to evaluate the restorative effects of volvoxspheres encapsulated withingMSCs and/or AML12 liver cellscellsonratswith the retrorsine-exposed CCl4-induced liver injuriesrats. The results showed that MSCs encapsulated in volvoxspheres differentiated into hepatocyte-like cells with a 2-fold increase in albumin expression and a 2.5-fold increasein cytokeratin 18 expression ina dynamic bioreactor. Moreover, thedatapresented significant reductions in AST and ALT levels after the implantationofvolvox spheres encapsulateding with both MSCs and AML12 hepatocytes in vivo. In contrast to the negative control group, histopathological analysis demonstratedliver repair and formation of the new liver tissue in groups implanted with volvox spheres containing cells. These results demonstrate that liver cells implanted withvolvox spheres encapsulated withing both MSCs and AML12 hepatocytes promote liver repair and liver tissue regenerationin liver failure caused by necrotizing agentssuch as retrorsine and CCl4. Hence, volvoxspheresencapsulated with ing MSCs and liver cells can be a promising and clinically effective therapy for liver injury.

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