Uncultured Autogenous Adipose-derived Regenerative Cells Promote Bone Formation During Distraction Osteogenesis in Rats

Abstract

Background Adipose-derived stem cells have recently shown differentiation potential in multiple mesenchymal lineages in vitro and in vivo. These cells can be easily isolated in large amounts from autologous adipose tissue and used without culturing or differentiation induction, which may make them relatively easy to use for clinical purposes; however, their use has not been tested in a distraction osteogenesis model. Question/purposes The question of this animal study in a rodent model of distraction osteogenesis was whether uncultured adipose-derived regenerative cells (ADRCs), which can easily be isolated in large amounts from autologous adipose tissue and contain several types of stem and regenerative cells, promote bone formation in distraction osteogenesis. We evaluated this using several tools: (1) radiographic analysis of bone density; (2) histological analysis of the callus that formed; (3) biomechanical testing; (4) DiI labeling (a method of membrane staining for postimplant celltracing); and (5) real-time polymerase chain reaction. Methods Sixty rats were randomly assigned to three groups. Physiological saline (control group), Type I collagen gel (collagen group), or a mixture of ADRC and Type I collagen gel (ADRC group) was injected into the distracted callus immediately after distraction termination. To a rat femur an external fixator was applied at a rate of 0.8 mm/day for 8 days.Results The bone density of the distracted callus in the ADRC group increased by 46% (p = 0.003, Cohen's d = 10.2, 95% confidence interval [CI] ± 0.180) compared with the control group at 6 weeks after injection. The fracture strength in the ADRC group increased by 66% (p = 0.006, Cohen's d = 1.32, 95% CI ± 0.180) compared with the control group at 6 weeks after injection. Real-time reverse transcription-polymerase chain reaction of the distracted callus from the ADRC group had higher levels of bone morphogenetic protein-2 (7.4 times higher), vascular endothelial growth factor A (6.8 times higher), and stromal cell-derived factor-1 (4.3 times higher). Cell labeling in the newly formed bone showed the ADRCs differentiated into osseous tissue at 3 weeks after injection. Conclusions The injection of ADRCs promoted bone formation in the distracted callus and this mechanism involves both osteogenic differentiation and secretion of humoral factors such as bone morphogenetic protein-2 or vascular endothelial growth factor A that promotes osteogenesis or angiogenesis.

Transplantation of Noncultured Stromal Vascular Fraction Cells of Adipose Tissue Ameliorates Osteonecrosis of the Jaw–Like Lesions in Mice

“…Hence, we investigated the effects of transplantation of noncultured SVF cells on both osseous and soft tissue wound healing of tooth extraction sockets. A recent study reported that transplantation of rat SVF cells with type I collagen gel promoted osteogenic ability in rat femoral distraction sites . Another study has showed that implantation of human SVF cells into bone fracture sites of nude rats enhances osteogenic ability.…”

“…A recent study reported that transplantation of rat SVF cells with type I collagen gel promoted osteogenic ability in rat femoral distraction sites. (31) Another study has showed that implantation of human SVF cells into bone fracture sites of nude rats enhances osteogenic ability. This study also showed spontaneous bone tissue and vessel formation within a fracture microenvironment with SVF.…”

Recent Advances in Stem Cell and Tissue Engineering

“…The parenchyma houses the hematopoietic stem cells, and the stoma part consists of the bone marrow stromal cells (MSCs) that have the capability to differentiate into several cell lines like osteoblasts, chondrocytes, adipocytes, etc. The clinical use of both bone-derived mesenchymal stem cells and adipose stem cells in bone tissue engineering has been reported using various models of bone regeneration such as osteogenesis [12,13], long bone defects [14,15], and calvarial defects [16,17]. Furthermore, co-administration of stem cells with cytokines has been reported to be efficient in bone repair as cytokines and growth factors like stromal derived factor-1 (SDF-1) can lead to increased migration and homing of stem cells to the defected site [18].…”

Impact of surgical innovation on tissue repair in the surgical patient

“…So too, injection of ASCs into the distracted callus has been shown to increase the bone density of osseous regenerate significantly compared with control. This is thought to be secondary to both accelerated osteogenic differentiation and secretion of humoral factors such as BMP‐2 and VEGF that can promote osteogenesis or angiogenesis. Interestingly, Sun et al reported that gene therapy using Runt‐related gene 2 (a master switch regulating the number of genes involved in osteoblast activation)‐modified ASCs promoted new bone formation during osteoporotic mandibular DO.…”