Jornal de pesquisa e terapia com células-tronco

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Development of 3D Alginate Encapsulation for Better Chondrogenic Differentiation Potential than the 2D Pellet System

Tanya Debnath, Usha Shalini, Lakshmi K Kona, VidyaSagar JVS, Suguna Ratnakar Kamaraju, Sumanlatha Gaddam and Lakshmi Kiran Chelluri

Introduction: Articular cartilage damage has reduced potential to regenerate. This is due to lack of blood supply at the site of injury and widely spread chondrocytes in dense extracellular matrix. Alternate strategies to regenerate the damaged tissue require exogenous supply of several chondrocyte implants. There are inherent challenges to optimize an appropriate tissue culture methodology in the enrichment of chondrocytes, thus necessitating the use of alginate hydrogel. Furthermore, human derived adipose stem cells provide an ideal tissue source to treat large focal defects.
Objectives: We explored the differentiation potential, expansion and growth kinetics of the human adipose derived stem cells (hADSCs) in 3D alginate microspheres. The growth pattern of articular chondrocytes was also studied in pellet system.
Methods: Isolated hADSCs and cartilage derived chondrocytes were cultured and characterized by flow cytometry and scanning electron microscopy (SEM). Cell viability and compatibility was studied using MTT, Annexin V FITC assays. RT-PCR was used to study chondrogenic regulation.
Results: Uniformly distributed cells encapsulated in alginate microspheres were imaged by SEM and they expressed multi-potent stem cell phenotype from the third passage. hADSCs were metabolically active within the alginate microspheres. The chondrocyte pellet culture from cartilage demonstrated lower growth potential as compared to alginate encapsulation. Apoptotic assays provided safety profile for the alginate during cell growth. The up regulation of cartilage specific genes like transforming growth factor-beta (TGF-β), collagen type-X, cartilage oligomeric matrix protein (COMP) and collagen type II was observed during the entire period of culture in alginate spheres.
Conclusion: The chondrocyte phenotype was conserved in pellet system with rich glycosaminoglycan (GAG) polysaccharides. Moreover, hADSCs could proliferate and differentiate into chondrogenic lineage within alginate matrix. Thus, an enriched chondrocyte requirement in alginate as a scaffold design would aid in the treatment of large focal defects.