Continuing Education Column Cartilage Repair Using Mesenchymal Stem Cells Byoung -Hyun Min, MD Department of Orthopedic Surgery, Ajou University College of Medicine E - mail : bhmin@ajou.ac.kr Hyun Jung Lee, PhD Cell Therapy Center, Ajou University Medical Center Young Jick Kim, PhD Cell Therapy Center, Ajou University Medical Center J Korean Med Assoc 2009; 52(11): 1077-1089 Abstract Articular cartilage defect rarely heals spontaneously due to its avascularity and low cellularity. Even small articular cartilage defects can develop into osteoarthritis, and subsequently, its management has been a major clinical concern. Although there are several treatment options for cartilage defect, no treatment has been established as a gold standard procedure. Bone marrow stimulation techniques which is equivalent to microfracture these days has been adapted as first line treatment, attributed to their technical easiness and minimal invasiveness to patients. However, this procedure has limitation in reproducing hyaline cartilage, so recent cell-based therapies using autologous chondrocytes or mesenchymal stem cells have drawn particular attention. MSCs regardless of its origin have shown significant potential for chondrogenesis. Novel approaches using MSCs as an alternative cell source for patient derived chondrocytes are currently on trial. In this review, stem cells from various origins considered as cell sources and potential application of mesenchymal stem cells to promote cartilage repair will be discussed. While differentiation of stem cell can be well controlled in vitro, it is not easy to predict the course of differentiation when the stem cell is transplanted. Some novel methods using physical stimulation and material based techniques for differentiation control are introduced in this context. Such differentiation control will be beneficial when it is adapted before transplantation. We call it preconditioning. Keywords: Articular cartilage defect; Cell therapy; Stem cell; Differentiation; Precondition 1077
Min BH Lee HJ Kim YJ Figure 1. Schematic diagram of autologous chondrocytes implantation: 200~300 miligrams cartilage is sampled from a less loaded area and then chondrocytes are isolated enzymatically. Chondrocytes are grown in vitro until there are enough cells to implant on the defect area of the articular cartilage. Cultured chondrocytes are injected into the cavity constructed by damaged area and sutured periosteum. 1078
Cartilage Repair Using Mesenchymal Stem Cells A B Figure 2. Arthroscopic finding: (A) Before operation, cartilage was detached from underlying subchondral bone (1.52 cm), (B) 1 year after autologous chondrocytes implantation, regenerated cartilage tissue showed normal appearance and was integrated well with neighboring normal cartilage. Figure 3. Arthroscopic view of microfracture procedure: Several holes were made on the subchondral bone with awl and each hole was apart from neighbor hole with regular distance. Blood clot drained from bone marrow includes mesenchymal stem cells and cytokine. Currently, microfracture has been accepted primary surgical option for full thickness articular cartilage defect. 1079
Min BH Lee HJ Kim YJ 4 months 12 months A B C Figure 4. Gross and histological findings (H&E) of the defects at 4 and 12 months: untreated group in the first row (A), microfracture-treated group in the second row (B), unseeded matrix combined with microfracture in the third row (C), and microfracture with chon-drocyte-augmented matrix in the fourth row (D). The defects in group 4 had the largest quantity of reparative tissue, achieving the level of the adjacent cartilage in some instances. D 1080
Cartilage Repair Using Mesenchymal Stem Cells Figure 5. Methods to regenerate cartilage using various kinds of cell sources: Cartilage defect could be treated using inflow of endogenous stem cells into the defect area by the bone marrow stimulating technique or implantation of exogenous cells from various origins. 1081
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Min BH Lee HJ Kim YJ <2W> <4W> Gross Safranin-O Gross Gross Figure 6. Artificial cartilage made by in vitro culture of chondrocytes seeded ECM scaffolds: Artificial cartilage looks grossly like hyaline cartilage since 2 weeks of culture. ECM distributed evenly over the scaffold at 2 weeks of culture in vitro. ECM of artificial cartilage was more increased and scaffold was degraded naturally at 4 weeks of culture. Figure 7. A novel cell stimulator based on the biological microelectromechanical system (BioMEMS) was manufactured to produce a cyclic compressive load (CCL) and applied to chondrogenic differentiation of MSCs. We could confirm the chondrogenesis of MSCs by mechanical stimulation with this system. 1084
Cartilage Repair Using Mesenchymal Stem Cells Control LIUS TGF LIUS/TGF Chondrocyles 0W 1W 2W 4W 6W Figure 8. Effects low intensity ultrasound stimulation on the chondrogenic differentiation of MSCs: Low intensity ultrasound stimulator (LIUS) could maintain the phnotype of chondrocytes longer than control and TGF treated group under the 3 -D cultural environment using PGA scaffold. 1085
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