Enhancement of Tendon–Bone Healing for Anterior Cruciate Ligament (ACL) Reconstruction Using Bone Marrow-Derived Mesenchymal Stem Cells Infected with BMP-2

Abstract

At present, due to the growing attention focused on the issue of tendon–bone healing, we carried out an animal study of the use of genetic intervention combined with cell transplantation for the promotion of this process. Here, the efficacy of bone marrow stromal cells infected with bone morphogenetic protein-2 (BMP-2) on tendon–bone healing was determined. A eukaryotic expression vector containing the BMP-2 gene was constructed and bone marrow-derived mesenchymal stem cells (bMSCs) were infected with a lentivirus. Next, we examined the viability of the infected cells and the mRNA and protein levels of BMP-2-infected bMSCs. Gastrocnemius tendons, gastrocnemius tendons wrapped by bMSCs infected with the control virus (bMSCs+Lv-Control), and gastrocnemius tendons wrapped by bMSCs infected with the recombinant BMP-2 virus (bMSCs+Lv-BMP-2) were used to reconstruct the anterior cruciate ligament (ACL) in New Zealand white rabbits. Specimens from each group were harvested four and eight weeks postoperatively and evaluated using biomechanical and histological methods. The bMSCs were infected with the lentivirus at an efficiency close to 100%. The BMP-2 mRNA and protein levels in bMSCs were significantly increased after lentiviral infection. The bMSCs and BMP-2-infected bMSCs on the gastrocnemius tendon improved the biomechanical properties of the graft in the bone tunnel; specifically, bMSCs infected with BMP-2 had a positive effect on tendon–bone healing. In the four-week and eight-week groups, bMSCs+Lv-BMP-2 group exhibited significantly higher maximum loads of 29.3 ± 7.4 N and 45.5 ± 11.9 N, respectively, compared with the control group (19.9 ± 6.4 N and 21.9 ± 4.9 N) (P = 0.041 and P = 0.001, respectively). In the eight-week groups, the stiffness of the bMSCs+Lv-BMP-2 group (32.5 ± 7.3) was significantly higher than that of the bMSCs+Lv-Control group (22.8 ± 7.4) or control groups (12.4 ± 6.0) (p = 0.036 and 0.001, respectively). Based on the histological findings, there was an increased amount of perpendicular collagen fibers formed between the tendon and bone in the bMSCs+Lv-Control and bMSCs+Lv-BMP-2 group, compared with the gastrocnemius tendons. The proliferation of cartilage-like cells and the formation of fibrocartilage-like tissue were highest within the bone tunnels in the bMSCs+Lv-BMP-2 group. These results suggest that this lentivirus can be used to efficiently infect bMSCs with BMP-2. Furthermore, tendons wrapped by bMSCs+Lv-BMP-2 improved tendon–bone healing.

Up-Regulation of TGF-β Promotes Tendon-to-Bone Healing after Anterior Cruciate Ligament Reconstruction using Bone Marrow-Derived Mesenchymal Stem Cells through the TGF-β/MAPK Signaling Pathway in a New Zealand White Rabbit Model

“…To the best of our knowledge, bone formation and tendon-to-bone healing are important factors in ACL reconstruction, and the healing of the tendon-to-bone interface is crucial to some orthopedic procedures and essential for the long-term survival of patients undergoing ACL reconstruction [27,28]. BMSCs are considered to be multipotent cells that can differentiate into mesenchymal-lineage cell types both in vivo and in vitro and have long been identified as promising molecules for engineered tissue repair and cell therapy [6,25]. Lim et al noted that MSCs promote better ACL reconstruction by biologically changing the normal healing process of the hamstring tendon grafts to their ambient bone tunnels, and the application of MSCs to the tendon grafts enhances graft osteointegration and healing through the formation of an intervening chondroid layer resembling the chondral enthesis of normal ACL insertions [29].…”

“…Approximately a quarter of patients have dissatisfactory long-term results, with clinical outcomes indicative of osteoarthritic changes in the knee joint [1]. Since the success and failure of surgery are largely dependent on the biological healing between the bone tunnel and graft, and the early connection of tendon-bone interface has been shown to be the weakest link [6], it is pivotal to investigate better strategies to improve the healing of tendon-to-bone interface.…”

Adenovirus-Mediated Expression of BMP-2 and BFGF in Bone Marrow Mesenchymal Stem Cells Combined with Demineralized Bone Matrix For Repair of Femoral Head Osteonecrosis in Beagle Dogs

“…BMP is the most useful growth factor with osteoinductive ability [32]. Among the known BMPs, BMP-2 has the most pronounced effect on promoting defect repair and in healing fractures [33]. bFGF, a potent angiogenic factor and bone regeneration factor, induces specialization of MSCs in vitro and bone repair in vivo [17].…”

TOB1 Deficiency Enhances the Effect of Bone Marrow-Derived Mesenchymal Stem Cells on Tendon-Bone Healing in a Rat Rotator Cuff Repair Model

“…Mesenchymal stem cells genetically modified to overexpress the developmental gene membrane type 1-matrix metalloproteinase also augmented rotator cuff healing at 4 weeks as shown by the presence of more fibrocartilage at the insertion site and improved biomechanical strength. Dong et al [23] found that MSCs genetically modified to overexpress BMP-2 improved tendon-bone healing in anterior cruciate ligament reconstructions. Tian et al [25] reported that MSCs significantly elevated the levels of ultimate load to failure, stiffness and stress in the Achilles tendons of rats, the effects of which were enhanced by chemokine (C-X-C motif) ligand 13.…”

“…Cell proliferation was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetra-zolium bromide (MTT) assays as described previously [23]. In brief, 72 h after infection, cells were trypsinized and resuspended in DMEM (1 × 10 6 cells/mL).…”