Accelerated fracture healing in the geriatric, osteoporotic rat with recombinant human platelet‐derived growth factor‐bb and an injectable beta‐tricalcium phosphate/collagen matrix

Abstract

Aging and osteoporosis contribute to decreased bone mass and bone mineral density as well as compromised fracture healing rates and bone repair quality. Consequently, the purpose of this study was to determine if recombinant human platelet-derived growth factor-BB (rhPDGF-BB) delivered in an injectable beta-tricalcium phosphate/collagen matrix would enhance tibial fracture healing in geriatric (>2 years of age), osteoporotic rats. A total of 80 rats were divided equally among four groups: Fracture alone; Fracture plus matrix; Fracture plus matrix and either 0.3 mg/mL or 1.0 mg/mL rhPDGF-BB. At 3 and 5 weeks, rats were euthanized and treatment outcome was assessed histologically, radiographically, biomechanically, and by micro-CT. Results indicated rhPDGF-BB-treated fractures in osteoporotic, geriatric rats caused a statistically significant time-dependent increase in torsional strength 5 weeks after treatment. The healed fractures were equivalent in torsional strength to the contralateral, unoperated tibiae. Data from the study are the first, to our knowledge, to underscore rhPDGF-BB efficacy in an injectable betatricalcium phosphate/collagen matrix accelerated fracture repair in a geriatric, osteoporotic rat model. ß

Recombinant human platelet‐derived growth factor BB (rhPDGF‐BB) and beta‐tricalcium phosphate/collagen matrix enhance fracture healing in a diabetic rat model

“…These findings support the hypothesis that rhPDGF-BB induced fracture callus cell proliferation and led to a subsequent increase in the structural properties of the callus in the diabetic rat. The findings of this study are supported by those reported by Hollinger et al, 40 in which rhPDGF-BB was found to accelerate fracture healing in geriatric, osteoporotic rats.…”

“…[37][38][39] In addition, rhPDGF-BB treatment at doses used in this study significantly enhanced fracture healing in aged, osteopenic rats. 40 Fracture callus cell proliferation was significantly higher in the diabetic rats treated with rhPDGF-BB, indicating that rhPDGF-BB treatment can ameliorate the deficit in callus cell proliferation observed in diabetic animals ( Figs. 1 and 2).…”

Repair of segmental bone defects in rabbit tibia promoted by a complex of β-tricalcium phosphate and hepatocyte growth factor

“…A representative photograph for determination of these areas is shown in Fig. 2 Effects of HGF on bone healing b-TCP and collagen promotes healing of bone fractures after a tibial osteotomy, compared with the material without PDGF-BB [6]. In rabbits, FGF-2 in a mixture of b-TCP and collagen facilitates healing of segmental bone defects [17].…”

“…It is highly likely that a combination of osteoinductive growth factors and scaffolds provides an appropriate osteoinductive environment for osteogenic cells. Promoting bone formation by applying polypeptide growth factors has been reported, including bone morphogenetic protein (BMP) [4], fibroblast growth factor-2 (FGF-2) [5], platelet-derived growth factor (PDGF) [6], and vascular endothelial cell growth factor (VEGF) [7].…”

“…It has excellent osteoconduction and resorbability when filling bone defects [15]. b-TCP is also a potential carrier for local delivery of polypeptide growth factors, including BMP-2 [16], FGF-2 [17], and PDGF [6], to promote bone healing. However, the effects of a complex of b-TCP and HGF on bone healing have yet to be addressed.…”