Effect of cyclic three-dimensional strain on cell proliferation and collagen synthesis of fibroblast-seeded chitosan-hyaluronan hybrid polymer fiber.

Background: Tissue engineering techniques using biodegradable three-dimensional (3D) scaffolds with cultured cells offer more potential alternatives for the treatment of severe ligament and tendon injuries. In tissue engineering, one of the crucial roles of 3D scaffolds is to provide a temporary template with the biomechanical characteristics of the native extracellular matrix (ECM) until the regenerated tissue matures. The purpose of the present study was to assess the effect of various cyclic mechanical stresses on cell proliferation and ECM production in a 3D scaffold made from chitosan and hyaluronan for ligament and tendon tissue engineering.

Local upregulation of stromal cell-derived factor-1 after ligament injuries enhances homing rate of bone marrow stromal cells in rats.

In the present study the local expression of stromal cell-derived factor-1 (SDF-1) after ligament injury and correlated change in the homing rate of systemically induced bone marrow stromal cells (BMSCs) to the injured site were clarified using a rat medial collateral ligament (MCL) injury model. SDF-1 was temporarily upregulated peaking at 2 weeks after injury. Correlated with the alteration in SDF-1 expression, the homing rate of systemically induced BMSCs was temporarily upregulated peaking at 2-4 weeks after injury.

Bone marrow stromal cells act as feeder cells for tendon fibroblasts through soluble factors.

Feeder effects of bone marrow stromal cells (BMSCs) on tendon fibroblasts were investigated using a co-culture method for the application of ligament or tendon tissue engineering and cell therapy. BMSCs had significant effects on enhancing cell proliferation, the ability of cells to migrate, and cell adhesivity but little effect on the extracellular matrix (ECM) synthesis of tendon fibroblasts without cell-cell contact. Furthermore, the conditioned medium from BMSCs, despite the existence of fibroblasts, significantly increased the number of fibroblasts.

Application of tissue engineering techniques for rotator cuff regeneration using a chitosan-based hyaluronan hybrid fiber scaffold.

Background: The current surgical procedures for irreparable rotator cuff tears have considerable limitations. Tissue engineering techniques using novel scaffold materials offer potential alternatives for managing these conditions.

Hypothesis: A chitosan-based hyaluronan hybrid scaffold could enhance type I collagen products with seeded fibroblasts and thereby increase the mechanical strength of regenerated tendon in vivo.

Limb length and girth discrepancy of unilateral congenital clubfeet.

There have been few reports about hypoplasia of the femur and tibia in congenital clubfeet. The subjects of this study were 38 patients with unilateral congenital clubfoot. All the measurements were significantly less in the affected side than in the normal side.

Juvenile Blount's disease: bilateral case with asynchronous onset.

We encountered a rare case of bilateral juvenile Blount's disease diagnosed as unilateral at the onset. The patient was a 9-year-old girl who visited our outpatient clinic with pain and deformity in the left knee. Examination of the left knee showed severe varus deformity.