Enhancement of chondrogenesis of human adipose derived stem cells in a hyaluronan-enriched microenvironment Shun-Cheng Wu a, b, c , Je-Ken Chang c, d, f , Chih-Kuang Wang c, e , Gwo-Jaw Wang c, d, f, g , Mei-Ling Ho a, b, c, * a Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan b Department of Physiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan c Orthopaedic Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan d Department of Orthopaedics, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan e Department of Medicinal and Applied Chemistry, College of Life Science, Kaohsiung Medical University, Kaohsiung, Taiwan f Department of Orthopaedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan g Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA, USA article info Article history: Received 17 July 2009 Accepted 24 September 2009 Available online 12 October 2009 Keywords: Human adipose derived stem cells (hADSCs) Hyaluronic acid/hyaluronan (HA)-enriched microenvironment Poly-(lactic-co-glycolic acid) (PLGA) scaffold Chondrogenesis Cell aggregation Articular cartilage tissue engineering abstract Microenvironment plays a critical role in guiding stem cell differentiation. We investigated the enhancing effect of a hyaluronan (HA)-enriched microenvironment on human adipose derived stem cell (hADSC) chondrogenesis for articular cartilage tissue engineering. The hADSCs were obtained from patients undergoing hip replacement. HA-coated wells and HA-modified poly-(lactic-co-glycolic acid) (HA/PLGA) scaffolds were used as the HA-enriched microenvironment. The mRNA expressions of chondrogenic (SOX-9, aggrecan and collagen type II), fibrocartilage (collagen type I), and hypertrophic (collagen type X) marker genes were quantified by real-time polymerase chain reaction. Sulfated glycosaminoglycan (sGAG) deposition was detected by Alcian blue, safranin-O staining, and dimethyl- methylene blue (DMMB) assays. Localized collagen type II was detected by immunohistochemistry. The hADSCs cultured in HA-coated wells (0.005–0.5 mg/cm 2 ) showed enhanced aggregation and mRNA expressions (SOX-9, collagen type II, and aggrecan) after 24 h, and sGAG content was also significantly increased after 9 days of culture. The HA-modified PLGA did not change the cell adherence and viability of hADSCs. The mRNA expressions of chondrogenic marker genes were significantly enhanced in hADSCs cultured in HA/PLGA rather than those cultured in the PLGA scaffold after 1, 3, and 5 days of culture. The hADSCs cultured in HA/PLGA produced higher levels of sGAG and collagen type II, compared to those in the PLGA scaffold after 4 weeks of cultures. Our results suggest that HA-enriched microenvironment induces chondrogenesis in hADSCs, which may be beneficial in articular cartilage tissue engineering. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction Articular cartilage has limited capacity to repair damage caused by trauma or disease because of its avascularity and low cellular mitotic activity [1]. The chondral lesions often result in progressive deterioration and eventual osteoarthritis [2]. Although total joint arthroplasty is one of the most common indications of a diffuse lesion, therapies for focal defect such as microfracture, multiple drilling, and cartilage gouging are also performed. However, current strategies are not able to restore the native structure of cartilage and may even increase the risk of further damage [3,4]. Accordingly, cell-based articular cartilage tissue engineering is a new emerging method that offers advantages over current treatment strategies [5]. In recent years, cell-based articular cartilage tissue engineering studies were focused on using either differentiated chondrocytes or bone marrow-derived mesenchymal stem cells (BMSCs) for trans- plantation [6]. However, limited proliferative capacity of differen- tiated chondrocytes and BMSCs possess a major challenge in providing adequate cell numbers for viable transplantations and cartilage repair. More importantly, the ex vivo expansion of chon- drocytes results in a loss of their phenotypes [7], and the prolifer- ative capacity of BMSCs are age dependent [8,9]. Adipose derived stem cells (ADSCs) have the following advantages over the afore- mentioned methods: (i) can be obtained with relatively little discomfort, (ii) causes lower donor site morbidity, and (iii) can be expanded to large numbers in vitro [10,11]. Therefore, ADSCs may * Corresponding author at: Department of Physiology, College of Medicine, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Kaohsiung 807, Taiwan. Tel.: þ(886) 7 3121101x2309/2553; fax: þ(886) 7 3234687/7 3219452. E-mail address: homelin@cc.kmu.edu.tw (M.-L. Ho). Contents lists available at ScienceDirect Biomaterials journal homepage: www.elsevier.com/locate/biomaterials 0142-9612/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.biomaterials.2009.09.089 Biomaterials 31 (2010) 631–640