Ze-jian Li

Antigen-extracted xenogeneic cancellous bone graft with recombinant human bone morphogenetic protein-2 enhances bone regeneration in repair of mandibular defect in rabbits

The effects of a large‐piece of xenogeneic bone that was separated from healthy pigs as a scaffold for the repair of a mandibular defect was investigated, and the applicability of antigen‐extracted xenogeneic cancellous bone (AXCB) soaked with recombinant human bone morphogenetic protein‐2 (rhBMP‐2) in bone defect repair was assessed. Mandibular defects were created in 48 New Zealand rabbits, and the animals were randomly divided into four groups, in which the mandibular defects were grafted with AXCB, AXCB soaked with rhBMP‐2, and autograft bone, or left blank. An equal number of animals from each group were classified into three time points (4, 8, and 12 weeks) after surgery for gross pathological observation, hematoxylin and eosin (H and E) staining, radiographic examination, and bone density measurement. H and E staining revealed that the area percentage of bone regeneration in the group of the AXCB/rhBMP‐2 graft was 27.72 ± 4.68, 53.90 ± 21.92, and 77.35 ± 9.83 at 4 weeks, 8 weeks, and 12 weeks, respectively. These results were better than those of the autogenous bone graft, suggesting that the group of the AXCB/rhBMP‐2 graft achieved a good osteogenic effect. With regard to the AXCB graft without rhBMP‐2, the area percentage of bone regeneration was only 14.03 ± 5.02, 28.49 ± 11.35, and 53.90 ± 21.92. Therefore, the osteogenic effect of the AXCB/rhBMP‐2 graft was demonstrated to have the best effect. In the group of the AXCB/rhBMP‐2 graft, the area percentage of bone regeneration increased, and the implanted materials were gradually degraded and replaced by autogenous bone regeneration over time. We conclude that the AXCB graft soaked with rhBMP‐2 showed good osteogenic effect in the repair of bone defects and good biocompatibility. AXCB serves as a good carrier of rhBMP‐2, which promotes bone formation.

Study of a new bone-targeting titanium implant–bone interface

New strategies involving bone-targeting titanium (Ti) implant–bone interface are required to enhance bone regeneration and osseointegration for orthopedic and dental implants, especially in osteoporotic subjects. In this study, a new dual-controlled, local, bone-targeting delivery system was successfully constructed by loading tetracycline-grafted simvastatin (SV)-loaded polymeric micelles in titania nanotube (TNT) arrays, and a bone-targeting Ti implant–bone interface was also successfully constructed by implanting the delivery system in vivo. The biological effects were evaluated both in vitro and in vivo. The results showed that Ti surfaces with TNT–bone-targeting micelles could promote cytoskeletal spreading, early adhesion, alkaline phosphatase activity, and extracellular osteocalcin concentrations of rat osteoblasts, with concomitant enhanced protein expression of bone morphogenetic protein (BMP)-2. A single-wall bone-defect implant model was established in normal and ovariectomized rats as postmenopausal osteoporosis models. Microcomputed tomography imaging and BMP-2 expression in vivo demonstrated that the implant with a TNT-targeting micelle surface was able to promote bone regeneration and osseointegration in both animal models. Therefore, beneficial biological effects were demonstrated both in vitro and in vivo, which indicated that the bone-targeting effects of micelles greatly enhance the bioavailability of SV on the implant–bone interface, and the provision of SV-loaded targeting micelles alone exhibits the potential for extensive application in improving local bone regeneration and osseointegration, especially in osteoporotic subjects.

Blood glucose and insulin and correlation of SLC25A13 mutations with biochemical changes in NICCD patients

Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) is a hereditary metabolic disease arising from biallelic mutations of SLC25A13. This study aimed to explore the characteristics of fasting blood glucose (FBG), fasting insulin (FINS) and C-peptide (C-P) levels in NICCD infants, analyze their SLC25A13 genetic mutations and further discuss the correlation between SLC25A13 genetic mutations and biochemical changes. Seventy-two cases of infants with cholestasis disease were gathered. Among them, 36 cases with NICCD diagnosis were case group. Meanwhile, 36 cases with unknown etiology but excluded NICCD were control group. FBG, FINS, C-P, ALT, AST, GGT, ALP, TG, HDL-C, LDL-C and Non-HDL-C were collected from all subjects, and DNA was extracted from venous blood for SLC25A13 mutations detection. The incidence of hypoglycemia was 3% in NICCD group. There were no significant statistical difference of FBG, FINS and C-P between NICCD and INC groups (P > 0.05). ALT, LDL-C and Non-HDL-C levels in NICCD group were lower than the INC group, while SLC25A13 mutations were associated with the level of GGT (P < 0.05). Ten different SLC25A13 genetic mutations were detected, among which, 851del4, IVS16ins3kb, IVS6+5 G > A and 1638ins23 mutations made up 82% of all mutations. The incidence of hypoglycemia may be higher in small gestational age infants with NICCD. Low LDL-C may be one of the characteristics of dyslipidemia in NICCD infants. There was a correlation between SLC25A13 gene mutations distribution and the GGT level, but the meaning of this finding remains to be further in-depth study. Impact statement This study aims to compare FBG, FINS, C-P, other biochemical and clinical manifestations between NICCD and non-NICCD infants, and discuss differential diagnosis of NICCD and INC beyond the genetic analysis. And investigate the correlation between SLC25A13 genetic mutations and biochemical changes. This work presented that incidence of hypoglycemia may be higher in small gestational age infants with NICCD. Low LDL-C may be one of the characteristics of dyslipidemia in NICCD infants. There was a correlation between SLC25A13 gene mutations distribution and the GGT level.

Case History Report: Cone Beam Computed Tomography for Implant Insertion Guidance in the Presence of a Dense Bone Island.

This article describes the use of cone beam computed tomography (CBCT) to diagnose a dense bone island (DBI) to facilitate implant insertion guidance in a patient followed up for 4 years. Suitable image-directed preplanning and periodic review by CBCT scanning is recommended when a jaw DBI is encountered in treatment planning for implant placement.

Ectopic osteogenesis effect of antigen-extracted xenogeneic cancellous bone graft with chitosan/rhBMP-2/bFGF sequential sustained-release nanocapsules:

To explore the ectopic osteogenesis effect of sequential sustained release application of recombinant human bone morphogenic protein-2 (rhBMP-2) and basic fibroblast growth factor (bFGF). Antigen-extracted xenogeneic cancellous bone coupled with growth factor-loaded chitosan nanocapsules were implanted in rats in intramuscular site in accordance with the following experimental pattern: group A: simultaneous burst release of rhBMP-2 and bFGF; group B: simultaneous sustained release of rhBMP-2 and bFGF; group C: preferential burst release of rhBMP-2, then sustained release of bFGF; group D: preferential burst release of bFGF, then sustained release of rhBMP-2; group E: sustained release of rhBMP-2 alone; group F: sustained release of bFGF alone, blank control group G: antigen-extracted xenogeneic cancellous bone graft only; negative control group H: not filled with anything. Specimens were obtained after executing the animals at 2 and 4 weeks for general observation and weighing, calcium content detection, micro-CT scanning and bone parameter measurement analysis, H&E staining, ALP staining and CD34 staining. The materials weight of A-2, B-2, C-2, A-4, B-4, C-4, D-4 and E-4 were significantly higher than that of preoperative materials (P < 0.05). The concentration of calcium of group B-4 was the highest (414.7 ± 12.03 mg/dl). Micro-CT scanning and bone parameter measurement analysis showed that the values of bone mineral density and trabecular thickness of group A, B, D, E at 4 weeks were both higher than the ones at 2 weeks (P < 0.05), and both the bone mineral density (367.52 ± 11.64 mg/cc) and the trabecular thickness (126.17 ± 11.36 μm) of group B-4 were the highest. H&E staining showed that a large region of calcified cartilage and haemopoietic tissues were newly formed, especially in group B-4. ALP staining and CD34 staining showed the most positive expression region in group B-4. Therefore, we conclude that simultaneous sustained release of rhBMP-2 and bFGF is the ideal way to release drug, and has better inducement of antigen-extracted xenogeneic cancellous bone graft.

Cultivation of periodontal tissue cell sheet by a new way for cell sheet engineering

We incorporate the idea by Akashi et al. which utilize disulfide bonds in forming the porous hydrogel. We further develop a system using γ-PGA as scaffold and disulfide bonds cleavage as the critical point of cell sheet detach system. Cytotoxicity tests showed good biocompatibility of the matrix PVDF membranes. Finally, the cell sheet detachment was successfully performed by adding cysteine after DPSC (Dental Pulp Stem Cell) or PDLSC (Periodontal Ligament Stem Cell) cultured for one week.

Activation of FAK promotes ERK-mediated osteogenesis for tensile force-subjected periodontal ligament cell

The exact mechanism of translate mechanical signals of the focal adhesion kinase (FAK) into osteoblast differentiation power. PDL cells and MG63 cells were under-100 kPa for different periods. The tension force of focal adhesion kinase (FAK) phosphorylation increases rapidly and upregulation of osteogenic protein expression in periodontal ligament cells, but not in MG63 cells with FAK antisense oligonucleotides decreased ALP and Osteocalcin (OC) secretion in cells transfected with PDL. These findings suggest that the tension of the activation of the FAK pathway in periodontal ligament cells, and regulate immune cytokines and regulation of bone morphogenetic protein.

Hepatic cirrhosis in a citrin-deficient infant

A 10-month-old female infant was referred to our hospital due to prolonged jaundice over 9 months and fever of 4 days. Physical examination revealed enlargement of the liver and spleen, as well as ascites. Liver ultrasound indicated multiple firm nodules. Laboratory tests showed hyperbilirubinemia, hypoglycemia, hypoalbuminemia and coagulopathy. Increased citrulline and methionine were detected by MS-MS analysis of serum amino acids, while large quantity of 4-hydroxyphenylpyruvic and 4-hydroxyphenyllactic acid were detected by GC-MS analysis of urine sample. The diagnosis was hepatic cirrhosis, and Citrin Deficiency was suspected to be the initial etiology. The diagnosis was confirmed by High-frequency mutation screening and direct sequencing of SLC25A13 gene that revealed a compound heterozygote of IVS16ins3kb and c.495delA mutation. This study provided additional clinical evidence to challenge the traditionally-assumed benign prognosis of patients with Neonatal Intrahepatic Cholestatic Caused by Citrin Deficiency (NICCD).

Advances in application of CBCT in diagnosis and guidance of operation designing of mandible fracture

The purpose was to illustrate and discuss the importance of cone beam computed tomography (CBCT) for accurate diagnosis of mandible fracture and designing of surgery. Two cases of mandible fracture were selected in this report. The history of patients revealed traumatic injuries on their faces because of accidents. The patients were primarily examined with 2D panoramic radiography which did not provide adequate information. Both cases were thereafter investigated preoperatively with CBCT. As the results, CBCT showed the displacement of fracture ends clearly which were useful for diagnosis and designing of surgery. We concluded that CBCT allowed accurate diagnosis of mandible fractures and also provided guidance for operational design.

Clinical study of Cone Beam CT imaging and 3D reconstruction aided detection accuracy of impacted tooth

The objective is to explore the efficiency and accuracy of the KODAK 9000C Dental Cone Beam CT imaging and 3D reconstruction to detect the impacted tooth and help decide the orthodontic-surgical treatment. 30 patients who were diagnosed to suffer an impacted tooth were selected to have a Cone Beam CT scan. After scanning, we used the technique of image processing and sharpening to make a clear three-dimensional reconstruction model of the impacted tooth. The three-dimensional reconstruction model had collected these medical information including site, extent, shape, and other characteristic features of the impacted tooth. Then we applied the processing technique which could adjust the color of the impacted tooth and the surrounding bone tissue so as to separate them, as the result, we could get a 3D reconstructed visualization image of the impacted tooth. A clinician could study the precise radiographic information about the segmented impacted tooth which helped to decide the orthodontics treatment to pull the impacted tooth back to its anatomical position. All the patients had accepted the orthodontics treatment aided by processed Cone Beam CT 3D reconstruction image and received a satisfying treatment outcome. It was concluded that the digital image processing technique could separate out the impacted tooth successfully and provide the accurate radiographic information to help the clinician decide an optimal orthodontics treatment plan.