Therapeutic Potential of Anterior Cruciate Ligament-Derived Stem Cells for Anterior Cruciate Ligament Reconstruction

Abstract

We recently reported that the ruptured regions of the human anterior cruciate ligament (ACL) contained vascular-derived stem cells, which showed the potential for high expansion and multilineage differentiation. In this study, we performed experiments to test the hypothesis that ACL-derived CD34 + cells could contribute to tendon-bone healing. ACL-derived cells were isolated from the rupture site of human ACL by fluorescenceactivated cell sorting. Following ACL reconstruction, immunodeficient rats received intracapsular administration of either ACL-derived CD34 + cells, nonsorted (NS) cells, CD34 -cells, or phosphate-buffered saline (PBS). We also performed in vitro cell proliferation assays and enzyme-linked immunosorbent assays for vascular endothelial growth factor (VEGF) secretion. We confirmed the recruitment of the transplanted cells into the perigraft site after intracapuslar injection by immunohistochemical staining at week 1. Histological evaluation showed a greater area of collagen fiber formation and more collagen type II expression in the CD34 + group than the other groups at the week 2 time point. Immunostaining with isolectin B4 and rat osteocalcin demonstrated enhanced angiogenesis and osteogenesis in the CD34 + group at week 2. Moreover, double immunohistochemical staining for human-specific endothelial cell (EC) and osteoblast (OB) markers at week 2 demonstrated a greater ability of differentiation into ECs and OBs in the CD34 + group. Microcomputerized tomography showed the greatest healing of perigraft bone at week 4 in the CD34 + cell group, and the failure load of tensile test at week 8 demonstrated the greatest biomechanical strength in the CD34 + group. Furthermore, the in vitro studies indicated that the CD34 + group was superior to the other groups in their cell proliferation and VEGF secretion capacities. We demonstrated that ACL-derived CD34 + cells contributed to the tendon-bone healing after ACL reconstruction via the enhancement of angiogenesis and osteogenesis, which also contributed to an increase in biomechanical strength.

Combined effect of ligament stem cells and umbilical-cord-blood-derived CD34+ cells on ligament healing

“…Similar to previous studies (Tei et al 2008;Mifune et al 2012Mifune et al , 2013, the transplantation of CD34+ cells into the injury site also promotes neovascularization of the host tissue. Peripheral blood CD34+ cells have been reported to differentiate into endothelial cells in vivo (Tei et al 2008).…”

Ectopic tissue engineered ligament with silk collagen scaffold for ACL regeneration: A preliminary study

“…Besides MSCs, blood vessels also have a rich supply of stem/ progenitor cells that display characteristic expression of CD34 surface markers [71,72]. Human ACL-derived CD34+ cells have been demonstrated to contribute to tendon-bone healing after ACL reconstruction in a rat model [73]. In this study, high expression levels of the angiogenesis-associated factor VEGF coupled with the presence of multi-potential regenerative cells maybe the reasons for the enhanced formation of fibrocartilage and mineralized bone formation within the bone tunnel.…”

Human iPSC-Derived Neural Crest Stem Cells Promote Tendon Repair in a Rat Patellar Tendon Window Defect Model

“…Recently, the longstanding dogma that the mammalian tendon is a postmitotic organ with limited regenerative reserve had been challenged by the discovery of stem cells isolated from tendon. [14][15][16] Though tendon stem cells show healing promotion, [17][18][19][20] the application of tendon stem cells for tendon repair needs further investigation.…”