Tissue-engineered Periosteum Research Articles

Elucidating Multiscale Periosteal Mechanobiology: A Key to Unlocking the Smart Properties and Regenerative Capacity of the Periosteum?

The periosteum, a thin, fibrous tissue layer covering most bones, resides in a dynamic, mechanically loaded environment. The periosteum also provides a niche for mesenchymal stem cells. The mechanics of periosteum vary greatly between species and anatomical locations, indicating the specialized role of periosteum as bone's bounding membrane. Furthermore, periosteum exhibits stress-state-dependent mechanical and material properties, hallmarks of a smart material. This review discusses what is known about the multiscale mechanical and material properties of the periosteum as well as their potential effect on the mechanosensitive progenitor cells within the tissue. Furthermore, this review addresses open questions and barriers to understanding periosteum's multiscale structure-function relationships. Knowledge of the smart material properties of the periosteum will maximize the translation of periosteum and substitute periosteum to regenerative medicine, facilitate the development of biomimetic tissue-engineered periosteum for use in instances where the native periosteum is lacking or damaged, and provide inspiration for a new class of smart, advanced materials.

Reconstruction of radial bone defects using the reinforced tissue-engineered periosteum

The objective of this study was to compare the osteogenic potential of reinforced and conventional tissue-engineered periosteum.Adipose-derived stromal cells of rabbits were induced into osteoblasts. Osteoinduced cells were seeded onto chitosan-tricalcium-phosphate-gelatin (Cs-TCP-Gel) and chitosan (Cs) scaffold, thus constructing the reinforced and conventional tissue-engineered periostea, respectively. Alkaline phosphatase (ALP) and von Kossa staining protocols were used to assess osteoblast phenotype.We surgically created a 15-mm-long bone defect in the right radii of New Zealand rabbits. The defects were treated with reinforced biomimetic periosteum in group A (n = 30) and treated with conventional tissue-engineered periosteum in group B (n = 30).Group C (n = 30) received CS-TCP-Gel scaffold alone, and group D (n = 30) served as untreated side (sham group). Radiologic,histologic, immunohistochemical, and histomorphometric studies were used to analyze healing pattern.ALP was remarkably expressed in the osteoinduced cells, indicating that osteoblastic differentiation was stable. Extracellular matrix calcification with dark nodule was detected by von Kossa staining. Compared with groups B and C, histologic results demonstrated that de novo osteogenesis proliferated in group A at 4 weeks. This was further confirmed by radiographic findings, which displayed the segmental gap completely healed by mature bone at 12 weeks. Robust expression of bone morphogenetic protein-2 in group A was also evident, whereas group D displayed poor osteogenic performance. Furthermore, histomorphometric and biomechanical results in group A demonstrated statistical significance over those in other groups (p 0.05).Our findings show that the reinforced tissue-engineered periosteum is superior to conventional one as a better biomimetic tissue,further indicating that it can repair the weight-bearing defects.

Enhancing bone formation by transplantation of a scaffold‐free tissue‐engineered periosteum in a rabbit model

The periosteum plays an important role in bone regeneration. However, the harvesting of autogenous periosteum is associated with disadvantages such as donor site morbidity and limited donor sources. This study uses an osteogenic predifferentiated cell sheet to fabricate a scaffold-free tissue-engineered periosteum (TEP). We generated an osteogenic predifferentiated cell sheet from rabbit bone marrow stromal cells (BMSCs) using a continuous culture system and harvested it using a scraping technique. Then, the in vitro characterization of the sheet was investigated using microscopy investigation, quantitative analysis of alkaline phosphatase (ALP) activity, and RT-PCR. Next, we demonstrated the in vivo osteogenic potential of the engineered sheet in ectopic sites together with a porous β-tricalcium phosphate ceramic. Finally, we evaluated its efficiency in treating delayed fracture healing after wrapping the cell sheet around the mandible in a rabbit model. The engineered periosteum showed sporadic mineralized nodules, elevated ALP activity, and up-regulated gene expression of osteogenic markers. After implantation in the subcutaneous pockets of the donor rabbits, the in vivo bone-forming capability of the engineered periosteum was confirmed by histological examinations. Additionally, when wrapping the engineered periosteum around a mandibular fracture gap, we observed improved bone healing and reduced amounts of fibrous tissue at the fracture site. The osteogenic predifferentiated BMSC sheet can act as a scaffold-free TEP to facilitate bone regeneration. Hence, our study provides a promising strategy for enhancing bone regeneration in clinical settings.

Comparative study between tissue‐engineered periosteum and structural allograft in rabbit critical‐sized radial defect model

The purpose of this study was to compare the efficacy of tissue-engineered periosteum (TEP) to allgeneic bone in repairing segmental bone defect. TEP was fabricated with osteoinduced rabbit bone marrow mesenchymal stem cells (MSCs) and porcine small intestinal submucosa (SIS). Allogrfats were cryopreserved radial segments of New Zealand Rabbits. Forty-eight radial critical-sized defects (CSD) were bilaterally produced in 24 rabbits. The defects were divided into three groups, group A, TEP implantation, group B, SIS implantation, and group C allograft. Bone defect reconstruction was kinetically analyzed at 4, 8, and 12 weeks by radiographic and histological scoring system. In group A, bone defects were radiographically and histologically healed with mature cortex and marrow cavity by 12 weeks, while none of the defects healed in group B. Group C showed a slow process of creeping substitution with lymphocyte infiltration. Statistical comparison confirmed that group A had a more efficient and rapid bone defect reparation as well as remodelling than Group B and C. In conclusion, TEP is superior to structural allograft in reconstruction of allogenic segmental bone defect. Pure SIS cannot guide bone regeneration in this rabbit model.

Evaluation of immunocompatibility of tissue-engineered periosteum

Tissue-engineered periosteum (TEP) and ‘intramembranous ossification’ may be an alternative approach to bone tissue engineering. In the previous study we attained successful bone defect reparation with homemade TEP in an allogenic rabbit model. But its allogenic immunocompatibility remained unknown. In this study TEP was constructed by seeding osteogenically induced mesenchymal stem cells of rabbit onto porcine small intestinal submucosa (SIS). A mixed lymphocyte reaction (MLR) was applied to evaluate the in vitro immunogenicity. The ratio of CD4+/CD8+ T-lymphocytes was tested kinetically to evaluate the systematic reaction of the TEP allograft, and a histological examination was performed to investigate local inflammation and ectopic osteogenesis. MLR indicated that TEP had a higher in vitro immunostimulation than SIS (p < 0.05). The ratios of CD4+/CD8+ lymphocytes increased in both TEP and SIS implanted groups in 2 weeks, followed by a decrease to a normal level from 2 to 4 weeks. Histological examination revealed modest lymphocyte infiltration for no more than 2 weeks. Moreover, subcutaneous ectopic ossification was observed in TEP allograft animals (8/12). Our findings imply that TEP has a certain immune reaction for the allograft, but it is not severe enough to impact osteogenesis in the allogenic rabbit model.

Synthesis of a Tissue-Engineered Periosteum with Acellular Dermal Matrix and Cultured Mesenchymal Stem Cells

Periosteal grafts can aid in bone repair by providing bone progenitor cells and acting as a barrier to scar tissue. Unfortunately, these grafts have many of the same disadvantages as bone grafts (donor site morbidity and limited donor sites). In this article, we describe a method of synthesizing a periosteum-like material using acellular human dermis and osteoblasts or mesenchymal stem cells (MSC). We show that osteoblasts readily attach to and proliferate on the acellular human dermis in vitro. In addition, osteoblasts retained the potential for differentiation in response to bone morphogenetic protein stimulation. Cells grown on the acellular human dermis were efficiently transfected with adenoviruses with no evidence of cellular toxicity. To assess for in vivo cell delivery and bone-forming potential, the acellular human dermis was seeded with green fluorescent protein (GFP)-positive MSCs, transfected with bone morphogenetic protein 2, wrapped around the adductor muscle in syngeneic mice, and used to treat critical-sized mandibular defects in nude rats. After 3 weeks, GFP-positive cells were still present, and bone had replaced the interface between the muscle and the constructs. After 6 weeks, critical-sized bone defects had been successfully healed. In conclusion, we show that an acellular human dermis can be used to synthesize a tissue-engineered periosteum capable of delivering cells and osteoinductive proteins.