Osteoinductivity of gelatin/β-tricalcium phosphate sponges loaded with different concentrations of mesenchymal stem cells and bone morphogenetic protein-2 in an equine bone defect model

Abstract

Fracture is one of the most life-threatening injuries in horses. Fracture repair is often associated with unsatisfactory outcomes and is associated with a high incidence of complications. This study aimed to evaluate the osteogenic effects of gelatin/β-tricalcium phosphate (GT) sponges loaded with different concentrations/ratios of mesenchymal stem cells (MSCs) and bone morphogenetic protein-2 (BMP-2) in an equine bone defect model. Seven thoroughbred horses were used in this study. Eight bone defects were created in the third metatarsal bones of each horse. Then, eight treatments, namely control, GT, GT/M-5, GT/M-6, GT/M-5/B-1, GT/M-5/B-3, GT/M-6/B-1, and GT/M-6/B-3 were applied to the eight different sites in a randomized manner (M-5: 2 × 10(5) MSCs; M-6: 2 × 10(6) MSCs; B-1: 1 μg of BMP-2; B-3: 3 μg of BMP-2). Repair of bone defects was assessed by radiography, quantitative computed tomography (QCT), and histopathological evaluation. Radiographic scores and CT values were significantly lower in the control group than in the other groups, while they were significantly higher in the GT/M-5/B-3 and GT/M-6/B-3 groups than in the other groups. The amount of mature compact bone filling the defects was greater in the GT/M-5/B-3 and GT/M-6/B-3 groups than in the other groups. The present study demonstrated that the GT sponge loaded with MSCs and BMP-2 promoted bone regeneration in an equine bone defect model. The GT/MSC/BMP-2 described here may be useful for treating horses with bone injuries.

Effect of recombinant human bone morphogenetic protein 2 (rhBMP-2) on equine bone formation: A preliminary in vitro and in vivo evaluation

“…Tsuzuki et al (2012) demonstrated that rhBMP-2/b-TCP sponges could significantly enhance bone regeneration as compared to either component alone. Moreover, significant improvements in the healing of surgically induced bone and osteochondral defects were demonstrated following treatment with rhBMP-2/b-TCP sponges in combination with MSCs (Seo et al 2014), or with MSCs and platelet rich plasma , Seo et al…”

“…Due to its osteoinductive effects (Devescovi et al 2008), it is approved as an alternative for cancellous bone grafts in humans in special indications (Govender et al 2002, Mont et al 2004. Previous studies demonstrated that recombinant human BMP-2 (rhBMP-2) loaded scaffolds accelerated bone regeneration in equine bone defect models (Perrier et al 2008, Seo et al 2014. Gelatin b-tricalcium phosphate (b-TCP) sponges loaded with rhBMP-2 also enhanced healing of osteochondral defects in horses , Seo et al 2015.…”

Use of a gelatin hydrogel membrane containing β-tricalcium phosphate for guided bone regeneration enhances rapid bone formation

“…Although the combination of gelatin and β-tricalcium phosphate has already been used as a biomaterial 8,9) , some issues, such as material safety and its properties remain to be solved. The G-TCP membranes were developed with the concept to apply not for big bone defects such as the critical-sized defects, but for smaller bone defects.…”

“…This technique is based on the concept that application of a membrane creates a protected space which facilitates the proliferation of angiogenic and osteogenic cells from the basal bone without interference from proliferating fibroblasts in the surrounding soft tissue 5) . To develop an ideal bioresorbable membrane for GBR, we chose gelatin because it has been used as a carrier of recombinant proteins, such as fibroblast growth factors (FGFs) and bone morphogenetic proteins (BMPs) [6][7][8][9] , and lacks antigenicity 10) . However, a membrane prepared from gelatin alone cannot function as a GBR membrane due to its mechanical weakness.…”

“…Although the combination of gelatin and β-tricalcium phosphate has already been applied as a biomaterial 8,9) , an ideal, thin, mechanically strong, safe, and effective membrane for GBR has not yet been developed. Since a GBR membrane is covered by the periosteum and mucosal tissue, it should be as thin as possible, and still maintain sufficient mechanical integrity to reduce complications, such as flap dehiscence and subsequent infection 12) .…”