Biomedical subjects

Lian Zhu

Publications and source records attributed to Lian Zhu.

10 recordsLinked to original sources

PubMed2006

Repair of experimental alveolar bone defects by tissue-engineered bone.

Alveolar bone resorption caused by periodontal diseases remains a difficult clinical problem to treat. Our purpose here was to develop protocols for repairing experimental horizontal alveolar bone defects. The procedure entailed isolating bone marrow stromal cells (BMSC). They were expanded and induced in vitro into osteogenic cells in a defined medium. Induced BMSCs were mixed with calcium alginate to form a gel form of cell-scaffold construct for developing engineered bone. A horizontal alveolar bone defect was created in 15 mongrel dogs, which was 5 mm high on each of two buccal sides at the location of mandibular premolar 3, 4, and molar 1. Without bias, the animals were separated into the following groups: (1) cell-scaffold construct as the experimental group; (2) calcium alginate alone as the control group A; (3) untreated as the control group B. Block sections of the defects were collected at 4, 12, and 24 weeks postsurgery, respectively, and processed for gross and histological observation as well as x-ray examination. The results showed that in vitro induced BMSCs exhibited an osteogenic phenotype. Histologically, bone nodule structure was observed in the tissue of the experimental group at 4 weeks postsurgery and the engineered bone became more mature after 12 weeks, which was similar to normal bone. At 12 weeks postsurgery, the height of repaired alveolar bone reached 2.43 +/- 0.93 mm, 0.98 +/- 0.87 mm, 0.78 +/- 0.75 mm for the experimental group, control groups A and B, respectively, with a significant difference between the experimental and control groups (p < 0.01). The average level of buccal alveolar ridge in experimental group, control groups A and B reached 48.59%, 19.74%, and 15.76% of the height of normal alveolus, respectively, with a significant difference between the experimental group and two control groups (p < 0.01). We thus conclude that BMSCs can be induced to become osteogenic and can be used as seed cells to engineer bone tissue and repair experimental alveolar bone defects.

Alginates↗

PubMed2006

Tissue-engineered bone repair of goat-femur defects with osteogenically induced bone marrow stromal cells.

Tissue engineering can generate bone tissue and has been shown to provide a better means of repairing weight-bearing bone defect. Previous studies, however, have heretofore been limited to the use of nonosteogenically induced bone marrow stromal cells (BMSCs) or the application of slow-degradation scaffolds. In this study, weight-bearing bone was engineered using osteogenically induced BMSCs. In addition, coral was used as a scaffold material, due to its proper degradation rate for the engineering and repair of a goat femur defect. A 25 mm long defect was created at the middle of the right femur in each of 10 goats. The rates of defect repair were compared in an experimental group of ten goats receiving implants containing osteogenically induced BMSCs and in the control group of goats (n = 10) receiving just coral cylinders. In the experimental group, bony union was observed by radiographic and gross view at 4 months, and engineered bone was further remodeled into newly formed cortexed bone at 8 months. There was increased gray density of radiographic rays in the repaired area, which was significantly different (p < 0.05) from that of the control group. H&E staining demonstrated that trabecular bone was formed at 4 months. Moreover, irregular osteon was observed at 8 months. Most importantly, the tissue-engineered bone segment revealed a similarity to the left-side normal femur in terms of bend load strength and bend rigidity, showing no significant difference (p > 0.05). In contrast, the coral cylinders of the control group showed no bone formation. Furthermore, almost complete resorption of the carrier had occurred, being evident at 2 months in the control group. H&E staining demonstrated that a small amount of residual coral particle was surrounded by fibrous tissue at 4 months whereas the residues disappeared at 8 months. Based on these results, we conclude that engineered bone from osteogenically induced BMSCs and coral can ideally heal critical-sized segmental bone defects in the weight-bearing area of goats.

Animals↗

PubMed2006

[Effect of adeno-BMP7 transfection on osteogenesis of BMSCs].

OBJECTIVE: To study the effect of adeno-BMP7 transfection on the biology of bone marrow stromal cells (BMSCs). METHODS: Bone marrow was obtained from the goat. The BMSCs were isolated and cultured at the second passage. Once the cells attached and formed a monolayer with 70%-80% confluency, adeno-BMP7 (M.O.I. = 100) was added to the cells. After three days, calcium node was examined with staining; cell-coral compound was replanted subcutaneously. RESULTS: With adeno-BMP7 transfection, BMP7 expression was detected with Western-blot; big calcium nodes were observed with staining. New bone formation was enhanced, which was evaluated by X-ray and histological examinations. CONCLUSIONS: BMSCs transfected with adeno-BMP7 show much stronger osteogenic ability.

Adenoviridae↗

PubMed2006

[Repair of canine segmental mandibular defects using autogenous bone marrow stromal cells and coralline hydroxyapatite].

OBJECTIVE: To repair segmental mandibular defects with autogenous bone marrow stromal cells (BMSCs) and coralline hydroxyapatite. METHODS: Isolated BMSCs were in vitro expanded and osteogenically induced. In 11 canines, a 3 cm segmental mandibular defect in right mandible was created. Five canine's defects were repaired with cell-scaffold constructs made from induced BMSCs and coralline hydroxyapatite (CHA); Others were repaired with CHA as control. The engineered bone was evaluated by X-ray, CT, gross and histological examination, biomechanical test 12, 26, 32 weeks post-operation respectively. RESULTS: BMSCs grew well on the CHA. X-ray and CT images showed better callus formation at connection sites in experimental group over time while worse formation at connection sites eventually in control group. At 32 weeks post-operation in experimental group, the defects were well repaired grossly. Histologically, there were bony healing and lamellar bone formation, in experimental group fibrous healing and woven bone formation in control group. Biomechanical test revealed no significant difference between experimental group and normal control group. CONCLUSIONS: Canine segmental mandibular defects can be ultimately repaired with the tissue-engineered bone generated by autogenous osteogenic BMSCs and CHA scaffold.

Animals↗

PubMed2005

Effect of exercise on the expression of adiponectin mRNA and GLUT4 mRNA in type 2 diabetic rats.

To investigate the impact of exercise on the expression of adiponectin and GLUT4 mRNA in type 2 diabetic rats, type 2 diabetic rat model was made. The diabetic rats were treated with swimming training for 8 weeks. The expression of adiponectin mRNA in perirenal fat and GLUT4 mRNA in skeletal muscles were assessed by reverse transcription polymerase chain reaction (RT-PCR) and the levels of blood glucose, serum insulin, and blood lipid were measured. Our results showed that the expression of adiponectin mRNA and GLUT4 mRNA in diabetic model group was decreased by 45% (P < 0.01), 43% (P < 0.01) respectively. The gene expression of adiponectin and GLUT4 was increased significantly in swimming group (P < 0.05 and P < 0.01, respectively). Compared with the model group, fasting insulin, TG, TC and FFA were decreased significantly in the training group (P < 0.05 or P < 0.01) as compared with model group. It is concluded that exercise can promote the expression of adiponectin mRNA and GLUT4 mRNA in type 2 diabetic rats, which may be one of the mechanisms responsible for the amelioration of insulin resistance in the rats.

Adiponectin↗

PubMed2005

Compressing different anatomical data types for the virtual soldier.

The Virtual Soldier Project endeavors to represent the baseline physiology and anatomy of a soldier using disparate but linked digital data types. Processing these data for storage, transmission and encryption requires different capabilities than are typical in a single codec. These representation and coding issues are illustrated and future directions are indicated.

Human Body↗

PubMed2004

[Repairing porcine knee joint osteochondral defects at non-weight bearing area by autologous BMSC].

OBJECTIVE: To test the possibility of using bone marrow stromal cells (BMSC) and biodegradable polymers to repair articular osteochondral defects at non-weight bearing area of porcine knee joints. METHODS: Bone marrows were harvested from 18 hybrid pigs. BMSC were cultured and in vitro expanded and induced with dexamethasone (group A) or with dexamethasone and transforming growth factor-beta1 (TGF-beta1) (group B) respectively. Immunohistochemistry and RT-PCR were used to evaluate chondrogenic differentiation of induced cells. Part of BMSC of 2 animals were retrovirally-labeled with green fluorescent protein (GFP). After induction and label, cells were seeded on a construct of polyglycolic acid (PGA) and polylactic acid (PLA) and co-cultured for 1 week before implantation. Total 4 osteochondral defects (8 mm in diameter, 5 mm in depth) in each animal were created at the non-weight bearing areas of knee joints on both sides. The defects were repaired with dexamethasone induced BMSC-PGA/PLA construct in group A, with dexamethasone and TGF-beta1 induced BMSC-PGA/PLA construct in group B, with PGA/PLA construct alone (group C) or left untreated (group D) as controls. Animals were sacrificed at 3 months (n = 6) or 6 months (n = 10) post-repair. Gross observation, histology, glycosaminoglycan (GAG) quantification and biomechanical test were applied to analyze the results. The two animals with GFP-labeled cells were sacrificed at 7 months post-repair to observe with confocal microscope the distribution of GFP-labeled cells in repaired tissue. RESULTS: Stronger expression of type II collagen and aggrecan were observed in BMSCs induced with both dexamethasone and TGF-beta1. At both time points, Gross observation and histology showed that the defects in most of group A were repaired by engineered fibrocartilage and cancellous bone with an irregular surface, minority defects were repaired by engineered hyaline cartilage and cancellous bone. However, in most of group B, the defects were completely repaired by engineered hyaline cartilage and cancellous bone. No repair or only fibrous tissue were observed in groups C and D. Besides, the compressive moduli of repaired cartilage in groups A and B reached 30.37% and 43.82% of normal amount at 3 months and 62.69% and 80.27% at 6 months respectively, which was further supported by the high levels of GAG contents in engineered cartilage of group A (78.03% of normal contents) and group B (no statistical difference from normal contents). More importantly, confocal microscope revealed the presence of GFP-labeled cells in engineered cartilage lacuna and repaired underlying cancellous bone. CONCLUSION: The results demonstrated that implanted BMSC can differentiate into either chondrocytes or osteoblasts at different local environments and repair a complex articular defect with both engineered cartilage and bone. TGF-beta1 and dexamethasone in vitro induction can promote chondrogenic differentiation of BMSC and thus improve the results of repairing articular defects.

Animals↗

PubMed2004

[Experimental study of porous TCP to generate tissue-engineered long bone].

To study bone-forming of a new kind of porous beta-TCP as the scaffold for tissue-engineering, defects at the mid-portion of the left and right ulna were created in dog, the defects were repaired with beta-TCP cylinder coated with BMSCs, and beta-TCP cylinders alone as control. X-rays showed the defects were better bridged by the replant with obscure edge and new bone formed in the canal and at the interface in experimental group after three month of operation, whereas in control group, the replants were obviously deformed into dissociated granule with unequal density with only little new bone formed at the interface. After six month, the defects were bridged by new bone with osteodermatous cavum medullare ossium, but in control group, the defects were bridged by high density in radiography without osteodermatous cavum medullare ossium, the diameter of the ular was obviously less than experimental group. There were significant differences between both groups at month one and two in the development pattern through radionuclide observation. By gross, the diameter of ular was smaller in control group than in experimental at month three, and the replants in control group was difficult to detach from the fibroid tissue around it, but in experimental group, there was much more new bone formation, and the surface was rough for the compound of new bone and beta-TCP undegraded completely. The new bone in experiment had been obviously remodeled at month six, but at this moment, the new bone was of infirmity in volume and form. HE staining of three months demonstrated new bone adhered to the surface on the core of beta-TCP in experimental group, but in control group, at the same place, osteoid was observed with much megacayocytes and capillaries. At month six, beta-TCP disappeared completely with new bone formed in both groups, but the volume and structure of the bone was better in experimental group than in control group. From this study it is concluded that the porous beta-TCP can be combined with BMSCs, and the combination could generate new bone to repair long bone defect.

Animals↗

PubMed2003

[Repair of alveolar bone defect with tissue engineered bone: an experimental study of dogs].

OBJECTIVE: To study the feasibility of repairing experimental horizontal alveolar bone defects by tissue engineering based on bone marrow stromal cells (BMSC). METHODS: Dog bone marrow mononuclear cells were isolated from the bone marrow by gradient centrifugation and then cultured in conditional medium to be induced to become osteogenic. Immunohistochemistry was used to examine the expression of core-binding factor alpha subunit 1 (Cbfa1), osteocalcin (OCN), and type I collagen in the cultured BMSCs. Histochemical technique was used to examine the expression of alkaline phosphatase (AKP) in the BMSCs. Inversed phase-contrast microscopy and electron microscopy were used to observe the morphology and proliferation of the BMSCs. Induced BMSCs at passage 3 were harvested and mixed with calcium alginate to form a gelatin form cell-scaffold construct. A horizontal alveolar bone defect (5 mm high) was created surgically in each buccal side of the mandibular premolars 3 and 4 and molar 1 of 11 dogs. The defects was randomly repaired with a cell-scaffold construct (experimental group, 20 teeth), calcium alginate alone (control group A, 15 teeth), or left untreated (control group B, 12 teeth). At four, twelve, and twenty-four weeks after operation, 2, 7, 2 dogs were killed respectively and block sections of mandibular bones at the defects were collected and processed for gross and histological observation as well as X-ray examination. The status of bone repair 12 weeks after operation in the 3 groups was compared. RESULT: In vitro induced BMSCs exhibited an osteogenic phenotype. Since the passage 3 calcium salt sedimentation could be seen in the extracellular stroma of BMSCs. Cbfa1, type I collagen, and AKP were expressed in the BMSCs in every passage. OCN was expressed since the second passage. Histologically, bone nodule structure was observed in the experimental group 4 weeks after operation. The engineered bone became more mature, similar to the normal bone, 12 weeks after operation. Twelve weeks after operation, the alveolar ridge regeneration amounted to a repair height of 2.43 +/- 0.93 mm, 0.98 +/- 0.87 mm, and 0.78 +/- 0.75 mm and reached 48.59%, 19.74%, and 15.76% of the original height in the experimental group, control group A, and control group B respectively, with a significant difference between the experimental and control groups A and B (all P < 0.01). CONCLUSION: BMSCs can be induced to become osteogenic and be used as seed cells to engineer bone tissue and repair experimental alveolar bone defect.

Alkaline Phosphatase↗

PubMed2003

[Construction and expression of retroviral vector containing bone morphogenetic protein-7].

AIM: To achieve stable and long-term expression of BMP-7 gene in bone marrow stem cells (BMSCs). METHODS: Retrovirus expression vector containing BMP-7 gene was constructed and transfected into packaging cells PT67. After puromycin selection and cells cloning, cell clones producing high level of recombinant virus were obtained. The viruses were used to infect directly BMSCs and the expression of BMP-7 gene in BMSCs was analyzed by immunohistochemical staining. RESULTS: Retrovirus vector containing BMP-7 gene was successfully reconstructed and BMP-7 was expressed in the BMSCs.The transfection rates was about 30%-40%. CONCLUSION: The construction of recombinant retrovirus vector containing BMP-7 gene can provide a reliable tool for the formation of bone or cartilage seed cells in the research of tissue engineering.

Bone Marrow Cells↗