Tehran University Medical Journal

Background: Nowadays, Human adipocyte-derived stem cells (hADSCs) has been widely used in tissue engineering because of its unique features such as extraction from more sources, more easily and non-invasive extraction methods. In order to increase cell-cell interactions, similar to embryonic pre-cartilage condensation, the use of three dimensional (3D) high-density cell culture systems such as Pellet and Micromass that simulates optimal condensation in chondrogenesis in vivo is necessary. Also, these culture systems provide the proper diffusion of nutrients. Aggrecan is a proteoglycan and one of the important components of extracellular matrix of cartilage tissue that plays an important role in the organization of the extracellular matrix. The high concentrations of aggrecan produces the osmotic properties that is necessary to normal tissue function of cartilage. In current study, Aggrecan gene expression was investigated during chondrogenesis of hADSCs in two Pellet and Micromass culture systems.
Methods: This experimental study was done in Department of Anatomical Sciences Department of Faculty Medical in Isfahan University of Medical Sciences, Iran, from April 2013 to January 2015. First, the abdominal adipose tissue was obtained from three patients after obtaining written consent during their liposuction surgeries. ADSCs were extracted by mechanical and enzymatic methods and were cultured in monolayer culture. Then, in order to induction of chondrogenic differentiation, 5×105 cells of third passage (P3) were transferred to three-dimensional culture systems Pellet and Micromass containing chondrogenic mediums in experimental groups of 7 and 14 days. The evaluation of aggrecan gene expression was performed by real-time PCR technique.
Results: Gene expression analysis revealed that aggrecan was significantly increased in micromass culture at day 14 compared to Pellet culture at days 14 and 7 (P≤0.01). Also, aggrecan was significantly increased in Micromass culture at day 7 compared to Pellet culture at day 7 (P≤0.05).
Conclusion: Due to higher expression of aggrecan gene in Micromass culture compared to Pellet culture, this system may be more efficient than Pellet culture in synthesis of aggrecan in chondrogenic differentiation of ADSCs.

The cartilage is a connective tissue that, due to the strength of its extracellular matrix, allows the tissue to tolerate mechanical stress without undergoing permanent deformation. It is responsible for the support of soft tissues and due to its smooth surface and elasticity, gives the joints the ability to slip and bend. excessive weight, excessive activity, or trauma can all cause cartilage to injury. The injury can lead to swelling, pain and varying degrees of mobility loss. The process of repairing musculoskeletal (orthopedic) injuries has led to problems in the medical field, which can be attributed to the inherent weakness of adult cartilage tissue. Therefore, this necessitates research focused on the development of a new restructuring strategy by combining chondrocytes or stem cells with scaffolds and growth factors to address these problems. Correspondingly, the recent tissue engineering strategies strongly support the simultaneous use of stem cells, scaffolds and growth factors. It has also been observed that due to the relatively low proliferation of transplanted chondrocytes, new cartilage models construction have examined the use of adipose-derived stem cells. Mature adipose tissue is produced as an important source of multi-functional stem cells that can be easily separated from the stromal vascular fraction (SVF) by adipose liposuction digestion. The adipose-derived stem cells are easily accessible without any serious complications and have the power to differentiate into several cell lines, including chondrocytes as well as, they evidence self-renewal when trapped in gel scaffolds such as collagen. Also, recent studies demonstrate some of the mechanisms involved in the process of making cartilage of adipose-derived stem cells in vitro and their restorative ability in bio-engineered scaffolds in the presence of growth factors. In addition, the important role of non-encoding mRNA molecules (miRNAs) has been identified in the process of chondrogenic differentiation of adipose-derived stem cells. Furthermore, in several studies, the effect of several miRNAs has been confirmed on the regulation of the cartilage differentiation of the adipose-derived stem cells and has also been associated with effective results. In this article, we will present an overview of the advance in adipose-derived stem cells application in cartilage regeneration.