Method for in vitro production of cartilage microtissues from scaffold-free spheroids composed of human adipose-derived stem cells

Abstract

Introduction: Cartilage damage is one of the injuries that is difficult for the human body to self-repair due to the avascular and completely mature tissue with only few stem or progenitor cells present. Recently, some studies showed that engineered cartilage tissues could be used to treat or improve this injury. This study aimed to produce the cartilage microtissues from the differentiation of scaffold-free spheroids composed of human adipose-derived stem cells.

Methods: Human adipose-derived stem cells (ADSCs) were isolated and expanded following the previously published study. They were then cultured in the non-adherent condition to produce spheroids. The spheroids of the ADSCs were collected and induced into cartilage microtissues in the inducible medium for 21 days. The cartilage microtissue was characterized by some cartilage phenotype markers, including the accumulation of extracellular matrix proteins (aggrecan, glycosaminoglycan, and type II collagen), and the expression of certain genes specific to chondrocytes (Sox9, Col2, Col1, and Acan).

Results: The results showed that the expression of chondrocyte-specific genes gradually increased during the 21 days of culture for differentiation. On day 21, the microtissues expressed aggrecan, glycosaminoglycan, and type II collagen proteins.

Conclusion: This study demonstrated that cartilage microtissues could easily be produced from scaffold-free spheroids from ADSCs. Thus, cartilage microtissues can be produced in this manner for in vivo transplantation to promote cartilage regeneration, or to produce cartilage tissues for in vitro studies.