Based on transversely isotropic theory, a finite element model for three-dimensional solid-liquid coupling defect repair of articular cartilage was established. By studying stress state of host cartilage near the restoration interface, we identified deformation type of cartilage and discussed the cause of restoration interface cracking. The results showed that the host cartilage surface node near the restoration interface underwent compression deformation in the condition of surface layer defect repair. When the middle layer, deep layer or full-thickness defect were repaired, the node underwent tensile deformation. At this point, the radial dimension of cartilage increased, which might cause restoration interface cracking. If elastic modulus of the tissue engineered cartilage (TEC) was lower (0.1 MPa, 0.3 MPa), the host cartilage surface layer and middle layer mainly underwent tensile deformation. While elastic modulus of TEC was higher (0.6 MPa, 0.9 MPa), each layer of host cartilage underwent compression deformation. Therefore, the elastic modulus of TEC could be increased properly for full-thickness defect repair. This article provides a new idea for evaluating the effect of cartilage tissue engineering repair, and has a certain guiding significance for clinical practice.
Objective To investigate the effect of simvastatin on inducing endothel ial progenitor cells (EPCs) homing and promoting bone defect repair, and to explore the mechanism of local implanting simvastatin in promoting bone formation. Methods Simvastatin (50 mg) compounded with polylactic acid (PLA, 200 mg) or only PLA (200 mg) was dissolved in acetone (1 mL) to prepare implanted materials (Simvastatin-PLA material, PLA material). EPCs were harvested from bone marrow of 2 male rabbits and cultured with M199; after identified by immunohistochemistry, the cell suspension of EPCs at the 3rd generation (2 × 106 cells/mL) was prepared and transplanted into 12 female rabbits through auricular veins(2 mL). After 3 days, the models of cranial defect with 15 cm diameter were made in the 12 female rabbits. And the defects were repaired with Simvastatin-PLA materials (experimental group, n=6) and PLA materials (control group, n=6), respectively. The bone repair was observed after 8 weeks of operation by gross appearance, X-ray film, and histology; gelatin-ink perfusion and HE staining were used to show the new vessels formation in the defect. Fluorescence in situ hybridization (FISH) was performed to show the EPCs homing at the defect site. Results All experimental animals of 2 groups survived to the end of the experiment. After 8 weeks in experimental group, new bone formation was observed in the bone defect by gross and histology, and an irregular, hyperdense shadow by X-ray film; no similar changes were observed in control group. FISH showed that the male EPC containing Y chromosome was found in the wall of new vessels in the defect of experimental group, while no male EPC containing Y chromosome was found in control group. The percentage of new bone formation in defect area was 91.63% ± 4.07% in experimental group and 59.45% ± 5.43% in control group, showing significant difference (P lt; 0.05). Conclusion Simvastatin can promote bone defect repair, and its mechanism is probably associated with inducing EPCs homing and enhancing vasculogenesis.
ObjectiveTo explore the application of three-dimensional (3-D) printing technique in repair and reconstruction of maxillofacial bone defect. MethodsThe related literature on the recent advance in the application of 3-D printing technique for repair and reconstructing maxillofacial bone defect was reviewed and summarized in the following aspects:3-D models for teaching, preoperative planning, and practicing; surgical templates for accurate positioning during operation; individual implantable prosthetics for repair and reconstructing the maxillofacial bone defect. Results3-D printing technique is profoundly affecting the treatment level in repair and reconstruction of maxillofacial bone defect. Conclusion3-D printing technique will promote the development of the repair and reconstructing maxillofacial bone defect toward more accurate, personalized, and safer surgery.
Objective To discuss the role of heparan sulfate (HS) in bone formation and bone remodeling and summarize the research progress in the osteogenic mechanism of HS. Methods The domestic and abroad related literature about HS acting on osteoblast cell line in vitro, HS and HS composite scaffold materials acting on the ani-mal bone defect models, and the effect of HS proteoglycans on bone development were summarized and analyzed. Results Many growth factors involved in fracture healing especially heparin-binding growth factors, such as fibroblast growth factors, bone morphogenetic protein, and transforming growth factor β, are connected noncovalently with long HS chains. HS proteoglycans protect these proteins from protease degradation and are directly involved in the regulation of growth factors signaling and bone cell function. HS can promote the differentiation of stem cells into osteoblasts and enhance the differentiation of osteoblasts. In bone matrix, HS plays a significant role in promoting the formation, maintaining the stability, and accelerating the mineralization. Conclusion The osteogenesis of HS is pronounced. HS is likely to become the clinical treatment measures of fracture nonunion or delayed union, and is expected to provide more choices for bone tissue engineering with identification of its long-term safety.
Objective To construct a new type of self-assembling peptide nanofiber scaffolds—RGDmx, and to study the cell compatibility of the new scaffolds and the proliferation and chondrogenic differentiation of precartilaginous stem cells(PSCs) in scaffolds. Methods PSCs were separated and purified from newborn Sprague Dawley rats by magnetic activated cell sorting and indentified by immunohistochemistry and immunofluorescent staining. The RGDmx were constructed by mixing KLD-12 and KLD-12-PRG at volume ratio of 1 ∶ 1. PSCs at passage 3 were seeded into the KLD-12 scaffold (control group) and RGDmx scaffold (experimental group). The proliferation of PSCs in 2 groups were observed with the method of cell counting kit (CCK) -8 after 1, 3, 7, and 14 days after culture. The RGDmx were constructed by mixing KLD-12-PRG and KLD-12 at different volume ratios of 0, 20%, 40%, 60%, 80%, and 100% and the prol iferation of PSCs was also observed. The complete chondrogenic medium (CCM) was used to induce chondrogenic differentiation of PSCs in different scaffolds. The differentiation of PSCs was observed by toluidine blue staining and RT-PCR assay. Results PSCs were separated and purified successfully, which were identified by immunohistochemistry and immunofluorescent staining methods. The results of CCK-8 showed that the absorbance (A) value in the experimental group increased gradually and reached the highest at 7 days; the A value in the experimental group was significantly higher than that in the control group at 7 days and 14 days (P lt; 0.05). Meanwhile, the A value in the RGDmx scaffold with a volume ratio of 40% was significantly higher than those in others (P lt; 0.05). After 14 days of induction culture with CCM, the toluidine blue staining results were positive in 2 groups; the results of RT-PCR showedthat the expression levels of collagen type II and the aggrecan in the experimental group were significantly higher than those in the control group (P lt; 0.05). Conclusion The self-assembling peptide nanofiber scaffold—RGDmx is an ideal scaffold for tissue engineer because it has good cell compatibility and more effective properties of promoting the differentiation of PSCs to chondrocytes.
Objective To explore the reliability and effectiveness of prediction of the pedicle length of the proximally-based anterolateral thigh (pALT) flap which was used to repair the defects following the resection of various malignant tumors using computed tomographic angiography (CTA). Methods The clinical data of 12 patients who met the selection criteria by using pALT flap to repair wounds left after malignant tumor resection between June 2015 and December 2020 were retrospectively analyzed. There were 5 males and 7 females; the age ranged from 16 to 80 years, with an average age of 54.4 years. After tumor resection, the soft tissue defect ranged from 15 cm×5 cm to 30 cm×12 cm; defect sites included 4 cases of lower abdomen, 3 cases of groin, 2 cases of thigh, and 3 cases of buttocks. Preoperative CTA was used to obtain the location information of the descending branch of the lateral femoral circumflex artery and its perforators by maximum density projection, and the length of the pedicle of pALT flap was estimated. Fasciocutaneous flap (5 cases) or myocutaneous flap (7 cases) were cut during operation to repair the defect, and the size of flap ranged from 20 cm×7 cm to 30 cm×12 cm. The donor site of thigh was directly sutured (11 cases) or repaired with skin graft (1 case). Bland-Altman analysis was used to detect the consistency between the pALT flap vascular pedicle length estimated by CTA and the pALT flap vascular pedicle length actually obtained during operation. ResultsOne case had distal blood supply disturbance of the flap and was repaired with skin graft after debridement; the remaining 11 flaps survived. All donor and recipient incisions healed by first intention. All 12 cases were followed up 1-12 months, with an average of 4.3 months. One patient died of pelvic tumor recurrence at 6 months after operation, and no tumor recurrence was found in the other patients. Preoperative CTA estimated that the length of pALT flap vascular pedicle was 9.3-24.7 cm, with an average of 14.7 cm; the actual length of pALT flap vascular pedicle was 9.5-25.0 cm, with an average of 14.8 cm. Bland-Altman analysis showed that there was no significant difference between the pALT flap vascular pedicle length estimated by CTA before operation and the pALT flap vascular pedicle length actually obtained during operation, and the average difference was 0.1 (95% consistency limit: –0.89, 0.74), indicating that they had good consistency. ConclusionCTA can be accurately used to localize the perforator and predict the possible pedicle length of the pALT flap. When performing a pALT flap surgery, preoperative CTA is helpful for surgeons to make a preliminary assessment of the difficult of the operation. The time for exploration of perforators and dissection of the vascular pedicle, and complications can be reduced, and the safety of the operation can be improved.
Objective To compare the effect between vascularization osteogenesis and membrane guided osteogenesis in the bone repair by the tissue engineered bone with pedicled fascial flap packing autologous red bone marrow (ARBM), so as to provide a reference for the bone defect repair in cl inic. Methods The tissue engineered bone was constructed with ARBM and the osteoinductive absorbing recombinant human materials with recombinant human bone morphogenetic protein 2. Sixty New Zealand rabbits (aged 4-5 months, weighing 2.0-2.5 kg) were randomly divided into group A (n=16), group B (n=22), and group C (n=22). The complete periosteum defect model of 1.5 cm in length was prepared in right ulnar bone, then the tissue engineered bone was implanted in the bone defect area in group A, the tissue engineered bonewith free fascial flap in group B, and the tissue engineered bone with pedicled fascial flap in group C. At 4, 8, 12, and 16 weeks, the tissue of bone defect area was harvested from 4 rabbits of each group for the general, histological, and immunohistochemical staining observations; at 8, 12, and 16 weeks, 2 rabbits of groups B and C, respectively were selected to perform ink perfusion experiment by axillary artery. Results The general observation showed that the periosteum-l ike tissues formed in the fascial flap of groups B and C, chondroid tissues formed in group B, new bone formed in group C, and the fibrous and connective tissues in group A at 4 and 8 weeks; a few porosis was seen in group A, more new bone in group B, and bone stump formation in group C at 12 and 16 weeks. Histological observation showed that there were few new blood vessels and new bone trabeculae in groups A and B, while there were large amounts of new blood vessels and mature bone trabeculae in group C at 4 and 8 weeks. There were a few new blood vessels and new bone trabeculae in group A; more blood vessels, significantly increased mature trabeculae, and the medullary cavity formation in group B; and gradually decreased blood vessels, the mature bone structure formation, and the re-opened medullary cavity in group C at 12 and 16 weeks. The immunohistochemical staining observation showed that the levels of CD105, CD34, and factor VIII were higher in group C than in groups A and B at different time points.The bone morphometry analysis showed that the trabecular volume increased gradually with time in 3 groups after operation; the trabecular volume in group C was significantly more than those in groups A and B at different time points (P lt; 0.05); and there was significant difference between groups A and B (P lt; 0.05) except the volume at 4 weeks (P gt; 0.05). The vascular image analysis showed that the vascular regenerative area ratio in group C was significantly higher than those in groups A and B at different time points (P lt; 0.05). The ink perfusion experiment showed that the osteogenic zone had sparse ink area with no obvious change in group B, while the osteogenic zone had more intensive ink area and reached the peak at 8 weeks, then decreased in group C. Conclusion The tissue engineered bone with pedicled fascial flap packing ARBM has the vascularization osteogenesis effect at early stage, but the effect disappears at late stage gradually when the membrane guided osteogenesis is main.
Aiming at the problem of scaffold degradation in bone tissue engineering, we studied the feasibility that controlls bone defect repair effect with the inhomogeneous structure of scaffold. The prediction model of bone defect repair which contains governing equations for bone formation and scaffold degradation was constructed on the basis of analyzing the process and main influence factors of bone repair in bone tissue engineering. The process of bone defect repair and bone structure after repairing can be predicted by combining the model with finite element method (FEM). Bone defect repair effects with homogenous and inhomogeneous scaffold were simulated respectively by using the above method. The simulation results illustrated that repair effect could be impacted by scaffold structure obviously and it can also be controlled via the inhomogeneous structure of scaffold with some feasibility.
Objective To evaluate the effectiveness of the submental island flap for repair of oral defects after radical resection of early-stage oral squamous cell carcinoma (OSCC). Methods Between February 2010 and August 2011, 15 cases of early-stage OSCC were treated. Of 15 cases, 9 were male and 6 were female, aged from 48 to 71 years (mean, 63 years). The disease duration was 28-73 days (mean, 35 days). Primary lesions included tongue (3 cases), buccal mucosa (8 cases), retromolar area (2 cases), and floor of mouth mucosa (2 cases). According to TNM classification of International Union Against Cancer (UICC, 2002) of oral cancer and oropharyngeal cancer, 2 cases were classified as T1N0M0 and 13 cases as T2N0M0. The results of the pathologic type were high differentiated squamous cell carcinoma in 11 cases and moderately differentiated squamous cell carcinoma in 4 cases. The defect after resection of the lesion ranged from 5 cm × 3 cm to 8 cm × 6 cm. All the cases underwent radical resection of the primary lesion and immediate reconstruction with submental island flap except 1 case with radial forearm free flap because of no definite venous drainage. The sizes of the submental island flap varied from 6 cm × 4 cm to 9 cm × 6 cm. Results Operation time ranged from 4 hours and 30 minutes to 7 hours and 10 minutes (mean, 5 hours and 53 minutes) in 14 cases undergoing repair with submental island flap. All the flaps survived completely in 13 cases except 1 case having superficial necrosis of the flap, which was cured after conservative treatment. Temporary marginal mandibular nerve palsy occurred in 1 case, and was cured after 3 months; submandibular effusion was observed in 3 cases, and was cured after expectant treatment. The follow-up period ranged from 8 to 15 months (mean, 10.5 months) in 14 cases undergoing repair with submental island flap. Hair growth was seen on the flap and became sparse after 3 months in 2 male cases. The appearance of the face, opening mouth, swallowing, and speech were recovered well in 14 cases, and the donor site had no obvious scar. The follow-up period was 13 months in 1 case undergoing repair with radical free forearm flap, and the appearance and function were recovered well. No local recurrence was found during follow-up. Conclusion The submental island flap has reliable blood supply, and could be harvested simply and rapidly. It can be used to repair oral defects in patients with early-stage OSCC after radical resection.
Icariin（ICA） is one of the main active ingredients in the Berberidaceae family Epimedium. It makes a variety of biological activities, such as promoting bone formation, antibacterial and anti-inflammatory, and regulating immunity. Periodontitis is a chronic inflammatory disease that is present in the soft and hard tissues of the periodontium. The ultimate goals of its treatment are the reconstruction of periodontal tissues and bone defect repairing. At present, conventional treatment of periodontitis fails to achieve the ideal periodontal tissue regeneration. In recent years, the rapid development of tissue engineering technology has brought new ideas for the treatment of periodontal disease and bone defect repairing. Because of its anti-inflammatory and osteogenic effects, ICA has great potential for the treatments of periodontitis and bone defect repairing. This paper summarizes the effect and the molecular mechanism of ICA in the treatment of periodontitis and bone defect repairing, and discusses its application prospect as a drug for periodontal adjuvant therapy. This paper aims to provide a theoretical basis for the research and application of ICA in periodontitis treatment and bone defect repairing.