PDGF has a growth-increasing effect on the both regions (Fig. Since Platelet-derived growth factor (PDGF) is known to facilitate ACL graft remodelling and ligamentization, PDGF was given in a dose-dependent manner to assess proliferation and collagen analysis of both middle and distal third regions. Remnant cells of the middle third region showed significantly higher expression of basal ligamentous differentiation-related genes (e.g., collagen type 1 and tenasin C) than those from the distal third region (pвЂ‰=вЂ‰0.013 and pвЂ‰=вЂ‰0.044, respectively) (Fig. Based on these latter findings, we performed experiments to test the hypothesis that human ACL remnant cells acquired from the site of ACL rupture have different potentials in cell differentiation based on their location.ДЇull size image Ligamentous differentiation Therefore, with remnant cells having the potential for expansion and multilineage differentiation, ruptured human ACL remnant tissue where the ACL contains numerous vascular-derived stem cells may show different characteristics in cell differentiation by their location. Histological observations of the uninjured human ACL have shown a different composition of cells in different ACL regions: chondrocyte-like cells were predominantly found in the more distal area (approximately 10 mm proximal to the tibial ligament insertion), while fibroblasts were predominantly found in the more proximal region (approximately 25 mm proximal of the tibial ligament insertion) 18.

However, with regard to their clinical application, potential advantages of remnant-derived stem cells are still questionable. 16 found that incorporation of ruptured ACL tissues in autologous grafts reduced tunnel enlargement in ACLR 16, 17. 14 demonstrated that ACL-derived CD34 + cells contributed to tendon-bone healing after ACLR via angiogenesis and osteogenesis enhancements 15. Recently, reports have shown that ruptured human ACL tissues can possess numerous vascular-derived stem cells and that ACL-derived CD34 + cells can promote healing and have high expansion and multilineage differentiation potential 7, 11, 12, 13. To overcome these issues, tissue engineering using stem cells has been widely explored as a means to achieve early graft healing, tendon regeneration, and bone integration. Indeed, the lack of vascularity within the tendon graft induces degeneration or micro ruptures during the early postoperative period 10. In most cases, non-augmented primary repair has been unsuccessful, and therefore ACL reconstruction is required 1, 4, 5.ДЇor surgical success, ACLR requires tendon graft healing in a surgically created bone tunnel and maturation (i.e., ligamentization) of the graft substance 4, 6, 7, 8, 9. Given the importance of its biomechanical function, surgical treatment is generally accepted as the standard procedure for restoring knee stability. It has been well documented that a completely ruptured ACL does not spontaneously heal because of poor vascular supply and an unfavourable intra-articular environment 3. Characteristics of the ACL remnant tissues should be considered when performing remnant-preserving or harvesting ACL remnants for tissue engineering.ДЄnterior cruciate ligament reconstruction (ACLR) is one of the most common surgical procedures in the field of orthopaedic sports medicine, with more than 130,000 procedures performed annually in the United States alone 1, 2.

On the other hand, the middle third region of ACL remnant had a strong tendency for osteogenic and ligamentous differentiation. The distal third region of the ACL remnant had a tendency for chondrogenic differentiation with higher expression of CD34 + cells. Cell proliferation rate did not differ in both middle and distal third regions of ACL remnant, but they showed different characteristics in cell differentiation depending on their location.

Both the middle and distal third regions of ACL remnant were analyzed using CD34 + cell counting. To determine and compare proliferation and differentiation potential of cells derived from distal and middle thirds of the ACL remnant, ACL remnant was initially marked at the distal third (within 10 mm from the tibial insertion) and middle third (between 10вЂ“20 mm from the tibial insertion) and then dissected. Histological and cytological observations of the human anterior cruciate ligament (ACL) had been described, but the differentiation potency based on their location is still unknown.

Acl ligament