Chondrogenic Differentiation of Mesenchymal Stem Cells from Human Umbilical Cord Blood / 대한정형외과학회잡지

PURPOSE: The aim of this study was to demonstrate the existence of circulating mesenchymal stem cells (MSC) in the human umbilical cord blood (hUCB) and to evaluate the chondrogenic differentiation potential of hUCB-derived MSC in vitro. MATERIALS AND METHODS: Fifty hUCB harvests were cultured in media supplemented with 10% fetal bovine serum. The adherent fibroblast-like cells were characterized by immunophenotyping and induced to differentiate into chondrocytes in the pellet culture with and without BMP-6. This study performed RTPCR of the chondrogenic markers, Safranin-O stain and type II collagen immunohistochemical stain. RESULTS: The mononuclear cells isolated from hUCB formed adherent colonies with an attached wellspread fibroblast-like morphology. The cells positively expressed the MSC-related antigens, but did not express the hematopoietic, HLA-DR, endothelial, or osteoclast antigens and could be induced to differentiate into chondrocytes under proper stimulation. BMP-6 increased the size of the pellet and the mRNA levels for aggrecan, type II collagen and type IX collagen and enhanced the levels of proteoglycan synthesis during chondrogenic differentiation. CONCLUSION: The homogenous fibroblast-like cells developed in cultures from hUCB with chondrogenic differentiation potential were considered to be MSC. Furthermore, it was found that BMP-6 enhanced chondrogenic differentiation of the hUCB-derived MSC in the pellet culture.

Treatment of Osteochondral Defects with Perichondrial Cells Embedded in Alginate Beads in Rabbit / 대한정형외과연구학회지

PURPOSE: The objective of this study was to investigate the use of cultured rib perichondrial cells embedded in alginate bead on healing in a rabbit osteochondral defect model. The degree of articular cartilage repair was evaluated histologically, histomorphometrically, and biochemical characteristics of the neocartilage. MATERIALS AND METHODS: A single defect, 3.5 mm wide by 3 mm deep, was created in the weight bearing area of the medial femoral chondyle in thirty New Zealand rabbits. The right defect filled with two alginate beads embedded with rabbit rib perichondrial cells, the left defect was empty as the control. The animals were killed at 1, 3, and 12 months, and the repair tissues were examined histologically, and histomorphometric differences were evaluated by an image analysis system. The defects also were examined biochemically for the glycosaminoglycan (GAG) and type II collagen to compare the results with normal articular cartilage. RESULTS: The attachment of repair tissue with the surrounding host tissue was incomplete, many specimens exhibited degenerative changes in adjacent tissue over a post transplant time period. Histomorphometric results showed that the repair groups (0.24+/-0.11 mm, -26.97 (25.62 mm) was decreased in surface roughness, and depression than controls (0.32+/-0.06 mm, -48.73 (32.59 mm) at 12 months. Repair area, repair area ratio, and repair thickness of the repair groups (6.89+/-2.1 mm2, 39.5+/-19.5%, 0.11 (0.01 mm) were increased than controls (2.65+/-2.35 mm2, 2.85+/-2%, 0.09+/-0.04 mm) at 12 months. After 12 months, the content of GAGs of neocartilage (36.45 microgram/mg) was similar to those of normal artilcular cartilage (36.74 microgram/mg), the percentage of type II collagen of the neocartilage increased up to 95%. CONCLUSION: Transplanted rib perichondrial cells were seen to proliferate to fill the osteochodral defect with neocartilage. Histomorphometric analysis should allow a more quantitative described the degree of articular cartilage repair.

Use of Polyurethane with Sustained Release Dexamethasone in Delayed Adjustable Strabismus Surgery

PURPOSE: To determine the effect of polyurethane with sustained release dexamethasone in delayed adjustable strabismus surgery in rabbits. METHODS: After recession of the superior rectus muscle(SRM), balanced salt solution or polyurethane film with/without sustained release dexamethasone was applied beneath and over the SRM in the control group(group C), polyurethane-steroid group(group P-S) and polyurethane group(group P), respectively. Delayed adjustment was performed once on each SRM at four and six weeks postoperatively by a masked observer. The possible length to adjust and the necessary force required for the adjustment, as well as the degree of any adhesions, were also evaluated. RESULTS: In the control group, adjustment was impossible in all of the eyes at four and six weeks postoperatively. In group P-S, adjustment was possible in 11 out of 11(11/11) eyes four weeks postoperatively and in 10/11 eyes six weeks postoperatively. In group P, adjustment was possible in 9/11 eyes four weeks postoperatively and in 10/12 eyes six weeks postoperatively. In addition, the degree of adhesion was significantly less in group P and in group P-S compared to the control group. The degree of adhesion between the SRM and the sclera was marginally better(p=0.051) in group P-S four weeks postoperatively than in group P. CONCLUSIONS: Use of polyurethane film could delay adjustment in most of the rabbit eyes for up to six weeks postoperatively. Sustained release dexamethasone is helpful for delaying adjustment in rabbit eyes until six week postoperatively without the need for frequent topical instillation of steroids.