Occurrence of oral Candida colonization and its risk factors among patients with malignancies in China.

OBJECTIVES: Oral colonization of Candida could lead to later development of oropharyngeal candidiasis or candidemia among the immunocompromised patients. This study aims to describe the occurrence and risk factors of oral Candida colonization in patients with malignancies. MATERIALS AND METHODS: From October 2012 to March 2013, 78 patients with pulmonary cancer (group I), 101 patients with gastrointestinal tract tumor (group II), 79 patients with hematopoietic system malignant tumor (group III), and 101 healthy controls were consecutively recruited in a hospital in Beijing, China. The oral rinse samples were taken and Candida species were identified; the enzymes activities were tested. RESULTS: In total, 110 and 27 Candida strains were isolated from 91 patients and 26 controls, respectively. The oral colonization rate with Candida albicans in group III (12.7 %) was significant lower than that in group I (30.8 %), group II (33.7 %), and control group (25.7 %). The oral colonization rates with non-albicans Candida species in group I, group II, and group III were 15.4, 10.9, and 12.7 %, respectively, while only one non-albicans Candida strain was identified in control group. The non-albicans Candida species exhibited a lower virulence than C. albicans. Age was an independent risk factor for Candida colonization in patients with pulmonary cancer and digestive tract malignant tumor, "Teeth brush <1 time/day" was an independent risk factor for Candida colonization in patients with hematopoietic system tumor. CONCLUSIONS: The differences of risk factors for oral Candida colonization in patients with different cancers require different strategies for the prevention and control of Candida infection. CLINICAL RELEVANCE: Old aged patients with pulmonary cancer and digestive tract malignant tumor are high-risk population for Candida colonization. Increasing frequency of teeth brush might be helpful for preventing Candida colonization.

Regulation of OPG and RANKL expressed by human dental follicle cells in osteoclastogenesis.

We investigate whether the expression of the receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG) in human dental follicle cells (HDFCs) regulated by colony stimulating factor 1 (CSF-1), parathyroid hormone-related protein (PTHrP) and bone morphogenetic protein-2 (BMP-2) contributes to osteoclastogenesis. Adolescent human impacted third mandibular molars were used to separate HDFCs. These cells were incubated with PTHrP (10 ng/ml), CSF-1 (25 ng/ml), or BMP-2 (100 ng/ml) for 0.5, 1, 3, 6 and 12 h. The expression of OPG and RANKL was investigated by immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR). Two co-culture systems and tartrate-resistant acid phosphatase (TRAP) staining were used to examine osteoclast formation. Scanning electron microscopy was utilized for the resorption pit assay. RANKL and OPG were expressed innately in HDFCs. Exogenous PTHrP, CSF-1 and BMP-2 chronologically regulated the expression of RANKL and OPG in HDFCs. PTHrP and CSF-1 had similar regulative patterns leading to the up-regulated expression of RANKL and the down-regulated expression of OPG and opposite for BMP-2. The number of TRAP-positive peripheral blood mononuclear cells (PBMCs) slightly increased in contacted co-culture of HDFCs and PBMCs, whereas secreted OPG from HDFCs inhibited osteoclastogenesis in the transwell co-culture system. Contacted co-culture of HDFCs and PBMCs exhibited small and shallow resorption pits, whereas in the transwell co-culture system, secreted OPG from HDFCs reduced the resorption pits, reflecting the difference in osteoclast production. Collectively, we found a dual action of HDFCs in osteoclastogenesis; moreover, PTHrP, CSF-1 and BMP-2 might influence osteoclastogenesis by regulating the expression of RANKL and OPG in HDFCs.

Application of 3-Dimensional Printing Technology to Kirschner Wire Fixation of Adolescent Condyle Fracture.

Condyle fractures are common in children and are increasingly treated with open reduction. Three-dimensional printing has developed into an important method of assisting surgical treatment. This report describes the case of a 14-year-old patient treated for a right condyle fracture at the authors' hospital. Preoperatively, the authors designed a surgical guide using 3-dimensional printing and virtual surgery. The 3-dimensional surgical guide allowed accurate alignment of the fracture using Kirschner wire without additional dissection and tissue injury. Kirschner wire fixation augmented by 3-dimensional printing technology produced a good outcome in this adolescent condyle fracture.

Association of Tooth Loss and Diet Quality with Acceleration of Aging: Evidence from NHANES.

BACKGROUND: Although tooth loss is widely recognized as a typical sign of aging, whether it is associated with accelerated aging, and to what extent diet quality mediates this association are unknown. METHODS: Data were collected from the National Health and Nutrition Examination Survey. The missing tooth counts were recorded as the number of edentulous sites. Phenotypic accelerated aging was calculated using 9 routine clinical chemistry biomarkers and chronological age. Healthy Eating Index 2015 (HEI-2015) score was used to evaluate diet quality. Multivariate logistic regression and linear regression were used to analyze the association between tooth loss and accelerated aging. Mediation analyses were used to examine the mediation role of diet quality in the association. RESULTS: The association between tooth loss and accelerated aging was confirmed. The highest quartile of tooth loss showed a positive association with accelerated aging (ß=1.090; 95% confidence interval, 0.555 to 1.625; P < .001). Diet quality decreased with increase number of missing teeth and showed a negative association with accelerated aging. Mediation analysis suggested that the HEI-2015 score partially mediated the association between tooth loss and accelerated aging (proportion of mediation: 5.302%; 95% confidence interval, 3.422% to 7.182%; P < .001). Plant foods such as fruits and vegetables were considered the key mediating food. CONCLUSIONS: The association between tooth loss and accelerated aging, as well as the partially mediating role of dietary quality in this association was confirmed. These findings suggested that more attention should be paid to the population with severe tooth loss and the changes of their dietary quality.

Proteomic profile of human dental follicle stem cells and apical papilla stem cells.

Dental stem cells have great potential in clinical practice as an adult mesenchymal stem cell, such as dental follicle and the apical papilla, have strong proliferation and differentiation characteristics. The developmental relevance and discrimination of them in the niche is not clear, which limits their application scenarios. The aim of this study was to investigate the intrinsical differences in cellular contents of DFSCs and SCAP by Tandem mass tag (TMT) labeling quantitative proteomics. Cell lysates were labeled and tracked by the combined use of TMT and LC-MS/MS. A total of 1622 proteins were detected, of which 421 were different and 12 were significantly up-regulated and 4 were significantly down-regulated. The results of proteomics support the application of stem cells in the treatment of neurodegenerative diseases such as Huntington's disease, Alzheimer's disease, Parkinson's disease and so on. The difference is related to cell proliferation and protection of neurons from inflammation and autophagy damage. Highly expressed proteins predict the special ability of DFSCs to stably proliferate and differentiate through CD13, MARCKS, and PAST1. The strong immune stability of SCAP is supported by NPC1.This study expands our understanding on the molecular mechanisms of tooth development and regeneration, and provide basic support for dental stem cells in clinical applications such as neurological and immune diseases.

Comparison of therapeutic effects of different mesenchymal stem cells on rheumatoid arthritis in mice.

BACKGROUND: Rheumatoid arthritis (RA) is a chronic and nonspecific autoimmune disease, which leads to joint destruction and deformity. To investigate the potential of human mesenchymal stem cells (MSCs) as a new therapeutic strategy for patients with RA, we compared the therapeutic effects of bone marrow derived MSCs (BMSCs), umbilical cord derived MSCs (UCs), and stem cells derived from human exfoliated deciduous teeth (SHED) on collagen-induced arthritis (CIA) in mice. METHODS: A total of 24 DBA/1 mice were infused with type II collagen to induce RA in the experimental model. MSC-treated mice were infused with UCs, BMSCs, and SHED, respectively. Bone erosion and joint destruction were measured by micro-computed tomographic (micro-CT) analysis and hematoxylin and eosin staining. The levels of tumor necrosis factor α (TNF-α) and interleukin-1ß (IL-1ß) were measured by immunohistochemistry and Enzyme-Linked Immunosorbent Assay (ELISA). RESULTS: Systemic delivery of MSCs significantly improved the severity of the symptoms related to CIA to greater extent compared with the untreated control group. Micro-CT revealed reduced bone erosions in the metatarsophalangeal joints upon treatment with MSCs. Additionally, according to histologic evaluation, reduced synovitis and articular destruction were observed in MSC-treated groups. The levels of TNF-α and IL-1ß in the serum and joints decreased with treatment by MSCs. CONCLUSION: Our findings suggest that systemic infusion of UCs, BMSCs, and SHED may significantly alleviate the effects of RA. The therapeutic effect of BMSCs was greater than that of SHED, while the UCs were shown to have the best therapeutic effect on CIA mice. In conclusion, compared with BMSCs and SHED, UCs may be a more suitable source of MSCs for the treatment of patients with RA.

Degradation in vitro and in vivo of ß-TCP/MCPM-based premixed calcium phosphate cement.

Premixed calcium phosphate cements (CPCs) have been developed to shorten the surgical time of conventional CPCs. However, there is lack of investigation on degradation behavior of premixed CPCs in vitro and in vivo. In this study, the premixed CPCs are prepared by mixing glycerol or polyethylene glycol (PEG) with the CPC power (ß-tricalcium phosphate (ß-TCP) and monocalcium phosphate monohydrate (MCPM)), and their degradation performances including the microstructure, chemical composition and mechanical properties are systematically evaluated both in vitro and in vivo (subcutaneous implantations in rabbits). When the premixed CPCs aged in PBS or FBS, results show weight loss of the specimens, decreased pH value and increased calcium ion concentration of aging media. Meanwhile, the setting products convert from dicalcium phosphate dihydrate (DCPD) to dicalcium phosphate anhydrous (DCPA), and no hydroxyapatite deposit. The specimen size and the molecular weight of non-aqueous solvent can modulate the setting product of premixed CPCs. For the larger specimens, DCPA is the main setting product, for the smaller ones, the composite contained DCPD and DCPA. With the decrease of the molecular weight of the non-aqueous solvent PEG, the setting product change from both DCPD and DCPA to DCPA due to the quicker exchange rate of PEG with water. After a period of subcutaneous implantation, the surface of the grafts obviously disintegrated with the formation of porous structures, but their internal morphology do not obviously change.

Salivary Secretory Immunoglobulin (SIgA) and Lysozyme in Malignant Tumor Patients.

Background. The purpose of this study is to understand the oral mucosal immune status of cancer patients and to make clear whether antibacterial proteins such as salivary secretory immunoglobulin (SIgA) and lysozyme in saliva were influenced by patients' health status and certain medical treatment therapy. Materials and Methods. This study included 221 patients with malignant tumor receiving antineoplastic treatment and 171 age- and gender-matched healthy controls. Results. The results showed that patients suffering malignant tumor had lower level of SIgA and higher level of lysozyme than healthy subjects (P < 0.05). The SIgA level was significantly different among different cancer tumors, while the lysozyme level showed significant difference only between patients with digestive tract malignant tumor and hematopoietic system tumor. Pretreatment before transplantation for hematopoietic system tumor patients significantly affected the lysozyme level other than SIgA. SIgA level was affected by many factors such as age, therapy factors, and oral hygiene. Conclusion. Malignant tumor and the antineoplaston may weaken the patients' oral mucosal immunity, influence levels of some salivary proteins, and decrease the level of SIgA, resulting in aggregation of oral bacteria and failure of clearing them from the oral cavity.

One size does not fit all: developing a cell-specific niche for in vitro study of cell behavior.

For more than 100years, cells and tissues have been studied in vitro using glass and plastic surfaces. Over the last 10-20years, a great body of research has shown that cells are acutely sensitive to their local environment (extracellular matrix, ECM) which contains both chemical and physical cues that influence cell behavior. These observations suggest that modern cell culture systems, using tissue culture polystyrene (TCP) surfaces, may fail to reproduce authentic cell behavior in vitro, resulting in "artificial outcomes." In the current study, we use bone marrow (BM)- and adipose (AD)-derived stromal cells to prepare BM-ECM and AD-ECM, which are decellularized after synthesis by the cells, to mimic the cellular niche for each of these tissues. Each ECM was characterized for its ability to affect BM- and AD-mesenchymal stem cell (MSC) proliferation, as well as proliferation of three cancer cell lines (HeLa, MCF-7, and MDA-MB-231), modulate cell spreading, and direct differentiation relative to standard TCP surfaces. We found that both ECMs promoted the proliferation of MSCs, but that this effect was enhanced when the tissue-origin of the cells matched that of the ECM (i.e. BM-ECM promoted the proliferation of BM-MSCs over AD-MSCs, and vice versa). Moreover, BM- and AD-ECM were shown to preferentially direct MSC differentiation towards either osteogenic or adipogenic lineage, respectively, suggesting that the effects of the ECM were tissue-specific. Further, each ECM influenced cell morphology (i.e. circularity), irrespective of the origin of the MSCs, lending more support to the idea that effects were tissue specific. Interestingly, unlike MSCs, these ECMs did not promote the proliferation of the cancer cells. In an effort to further understand how these three culture substrates influence cell behavior, we evaluated the chemical (protein composition) and physical properties (architecture and mechanical) of the two ECMs. While many structural proteins (e.g. collagen and fibronectin) were found at equivalent levels in both BM- and AD-ECM, the architecture (i.e. fiber orientation; surface roughness) and physical properties (storage modulus, surface energy) of each were unique. These results, demonstrating differences in cell behavior when cultured on the three different substrates (BM- and AD-ECM and TCP) with differences in chemical and physical properties, provide evidence that the two ECMs may recapitulate specific elements of the native stem cell niche for bone marrow and adipose tissues. More broadly, it could be argued that ECMs, elaborated by cells ex vivo, serve as an ideal starting point for developing tissue-specific culture environments. In contrast to TCP, which relies on the "one size fits all" paradigm, native tissue-specific ECM may be a more rational model to approach engineering 3D tissue-specific culture systems to replicate the in vivo niche. We suggest that this approach will provide more meaningful information for basic research studies of cell behavior as well as cell-based therapeutics.

The Effects of Diamond-Like Carbon Films on Fretting Wear Behavior of Orthodontic Archwire-Bracket Contacts.

This study aims to assess the effects of diamond-like carbon (DLC) films on fretting wear behavior of orthodontic archwire-bracket contacts. 'Mirror-confinement-type electron cyclotron resonance (MCECR) plasma sputtering' was utilized to deposit carbon films on stainless steel archwires and brackets. Nanostructure of carbon films such as the bonding structure, cross-sectional thickness and surface roughness were studied. The fretting wear behavior of various archwire-bracket contacts were investigated by using a self-developed tester in ambient air and artificial saliva. The results indicated that DLC-coated wires showed significantly low friction coefficient than the uncoated wires independently of the applied environments. Nevertheless, the DLC-coated and uncoated brackets showed no significant differences in the friction coefficient. Microscopic analysis showed that low wear took place for the DLC-coated surfaces. It is proposed that the application of DLC coating on archwires can decrease the orthodontic fretting wear and coefficient of friction. Unfortunately it does not affect the frictional properties for brackets at present.

ß2-Adrenergic signal transduction plays a detrimental role in subchondral bone loss of temporomandibular joint in osteoarthritis.

The present study tested whether activation of the sympathetic tone by aberrant joint loading elicits abnormal subchondral bone remodeling in temporomandibular joint (TMJ) osteoarthritis. Abnormal dental occlusion was created in experimental rats, which were then intraperitoneally injected by saline, propranolol or isoproterenol. The norepinephrine contents, distribution of sympathetic nerve fibers, expression of ß-adrenergic receptors (ß-ARs) and remodeling parameters in the condylar subchondral bone were investigated. Mesenchymal stem cells (MSCs) from condylar subchondral bones were harvested for comparison of their ß-ARs, pro-osteoclastic gene expressions and pro-osteoclastic function. Increases in norepinephrine level, sympathetic nerve fiber distribution and ß2-AR expression were observed in the condylar subchondral bone of experimental rats, together with subchondral bone loss and increased osteoclast activity. ß-antagonist (propranolol) suppressed subchondral bone loss and osteoclast hyperfunction while ß-agonist (isoproterenol) exacerbated those responses. MSCs from experimental condylar subchondral bone expressed higher levels of ß2-AR and RANKL; norepinephrine stimulation further increased their RANKL expression and pro-osteoclastic function. These effects were blocked by inhibition of ß2-AR or the PKA pathway. RANKL expression by MSCs decreased after propranolol administration and increased after isoproterenol administration. It is concluded that ß2-AR signal-mediated subchondral bone loss in TMJ osteoarthritisis associated with increased RANKL secretion by MSCs.

Biphasic silica/apatite co-mineralized collagen scaffolds stimulate osteogenesis and inhibit RANKL-mediated osteoclastogenesis.

The effects of a biphasic mineralized collagen scaffold (BCS) containing intrafibrillar silica and apatite on osteogenesis of mouse mesenchymal stem cells (mMSCs) and inhibition of receptor activator of nuclear factor κB ligand (RANKL)-mediated osteoclastogenesis were investigated in the present study. mMSCs were cultured by exposing to BCS for 7 days for cell proliferation/viability examination, and stimulated to differentiate in osteogenic medium for 7-21 days for evaluation of alkaline phosphatase activity, secretion of osteogenic deposits and expression of osteoblast lineage-specific phenotypic markers. The effect of BCS-conditioned mMSCs on osteoclastogenesis of RAW 264.7 cells was evaluated by tartrate-resistant acid phosphatase staining and resorption pit analysis. The contributions of mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3 kinase (PI3K) signal transduction pathways to osteogenesis of mMSCs and their osteoprotegerin (OPG) and RANKL expressions were also evaluated. Compared with unmineralized, intrafibrillarly-silicified or intrafibrillarly-calcified collagen scaffolds, BCS enhanced osteogenic differentiation of mMSCs by activation of the extracellular signal regulated kinases (ERK)/MAPK and p38/MAPK signaling pathways. After mMSCs were exposed to BCS, they up-regulated OPG expression and down-regulated RANKL expression through activation of the p38/MAPK and PI3K/protein kinase B (Akt) pathways, resulting in inhibition of the differentiation of RAW 264.7 cells into multinucleated osteoclasts and reduction in osteoclast function. These observations collectively suggest that BCS has the potential to be used in bone tissue engineering when the demand for anabolic activities is higher than catabolic metabolism during the initial stage of wound rehabilitation.

Repair of flexor tendon defects of rabbit with tissue engineering method.

OBJECTIVE: To repair rabbit tendon defects with tissue engineering method. METHODS: The third passage of fetal skin fibroblast cells was labeled with 5-bromo-2' deoxyuridine (Brdu) and then seeded on human amnion extracellular matrix (HA-ECM). Using 1 cm-long-Achilles tendon defects as repairing models in the experimental group, tendon defects were core bridged with polydioxanone (PDS) and then capsulated with the complex of fibroblasts-HA-ECM. In the control group I, defective tendons were sutured with PDS following the former procedure and capsulated with HA-ECM (without fibroblasts). In the control group II, only PDS was applied to connect the defective tendons. Gross examination, light microscopy, scanning electronmicroscopy and biomechanical measurement of the repaired tendons were respectively performed at postoperative 1, 2, 3 month as well as immunohistochemical examination. RESULTS: The optimal cell concentration for seeding fibroblasts was 3.5 x 10(6) cells/ml. Cells grew well and radiated or paralleled on HA-ECM. Immunohistochemistry showed that the labeled seed fibroblasts played an important role in tendonization. The results of light microscopy, electron microscopy, and biomechanical assessment suggested that the rate and quality of tendonization in the experimental group was superior to those of the control group I and II. The tensile strength in the experimental group was the greatest, the next was in the control group I, and the worst in the control group II (P<0.05). CONCLUSIONS: HA-ECM is the excellent carrier for fibroblasts. Fibroblasts-HA-ECM complex has the capability to repair tendon defect and to tendonize with rapid rate and good performance three months after operation. Its tensile strength is 81.8% of that of normal tendon.

Effect of jaw opening on the stress pattern in a normal human articular disc: finite element analysis based on MRI images.

INTRODUCTION: Excessive compressive and shear stresses are likely related to condylar resorption and disc perforation. Few studies have reported the disc displacement and deformation during jaw opening. The aim of this study was to analyze stress distribution in a normal articular disc during the jaw opening movement. METHODS: Bilateral MRI images were obtained from the temporomandibular joint of a healthy subject for the jaw opening displacement from 6 to 24 mm with 1 mm increments. The disc contour for the jaw opening at 6 mm was defined as the reference state, and was used to establish a two dimensional finite element model of the disc. The contours of the disc at other degrees of jaw opening were used as the displacement loading. Hyperelastic material models were applied to the anterior, intermediate and posterior parts of the disc. Stress and strain trajectories were calculated to characterize the stress/strain patterns in the disc. RESULTS: Both the maximum and minimum principal stresses were negative in the intermediate zone, therefore, the intermediate zone withstood mainly compressive stress. On the contrary, the maximum and minimum principal stresses were most positive in the anterior and posterior zones, which meant that the anterior and posterior bands suffered higher tensile stresses. The different patterns of stress trajectories between the intermediate zone and the anterior and posterior bands might be attributed to the effect of fiber orientation. The compression of the intermediate zone and stretching of the anterior and posterior bands caused high shear deformation in the transition region, especially at the disc surfaces. CONCLUSIONS: The stress and strain remained at a reasonable level during jaw opening, indicating that the disc experiences no injury during functional opening movements in a healthy temporomandibular joint.

Investigation of dental pulp stem cells isolated from discarded human teeth extracted due to aggressive periodontitis.

Recently, human dental pulp stem cells (DPSCs) isolated from inflamed dental pulp tissue have been demonstrated to retain some of their pluripotency and regenerative potential. However, the effects of periodontal inflammation due to periodontitis and its progression on the properties of DPSCs within periodontally compromised teeth remain unknown. In this study, DPSCs were isolated from discarded human teeth that were extracted due to aggressive periodontitis (AgP) and divided into three experimental groups (Groups A, B and C) based on the degree of inflammation-induced bone resorption approaching the apex of the tooth root before tooth extraction. DPSCs derived from impacted or non-functional third molars of matched patients were used as a control. Mesenchymal stem cell (MSC)-like characteristics, including colony-forming ability, proliferation, cell cycle, cell surface antigens, multi-lineage differentiation capability and in vivo tissue regeneration potential, were all evaluated in a patient-matched comparison. It was found that STRO-1- and CD146-positive DPSCs can be isolated from human teeth, even in very severe cases of AgP. Periodontal inflammation and its progression had an obvious impact on the characteristics of DPSCs isolated from periodontally affected teeth. Although all the isolated DPSCs in Groups A, B and C showed decreased colony-forming ability and proliferation rate (P < 0.05), the decreases were not consistent with the degree of periodontitis. Furthermore, the cells did not necessarily show significantly diminished in vitro multi-differentiation potential. Only DPSCs from Group A and the Control group formed dentin-like matrix in vivo when cell-seeded biomaterials were transplanted directly into an ectopic transplantation model. However, when cell-seeded scaffolds were placed in the root fragments of human teeth, all the cells formed significant dentin- and pulp-like tissues. The ability of DPSCs to generate dental tissues decreased when the cells were isolated from periodontally compromised teeth (P < 0.05). Again, increased periodontal destruction was not necessarily followed by a decrease in the amount of dentin- and pulp-like tissue formed. These findings provide preliminary evidence that periodontally compromised teeth might contain putative stem cells with certain MSC properties, as long as the vitality of the pulp has not been totally damaged. Whether these cells can serve as a source of autologous multipotent MSCs for clinical regenerative therapies warrants further investigation with larger sample sizes and various types of periodontitis.

Intrafibrillar-silicified collagen scaffolds enhance the osteogenic capacity of human dental pulp stem cells.

OBJECTIVES: The present study investigated the effects of intrafibrillar-silicified collagen scaffolds (ISCS) on the osteogenic differentiation of human dental pulp stem cells (hDPSCs) in vitro and in vivo. METHODS: The hDPSCs were co-cultured with ISCS or nonsilicified collagen scaffolds (NCS) in control medium (CM) or osteogenic differentiation medium (ODM). Cell cycle and cell apoptosis were analyzed with flow cytometry to measure the viability of hDPSCs. Reverse transcription-polymerase chain reaction (RT-PCR) and western blotting were used to evaluate the expression levels of osteogenic marker genes and proteins of hDPSCs. Alkaline phosphatase (ALP) staining and alizarin red S assay were used to evaluate the ALP activity of hDPSCs and their calcium deposition potential. In addition, hDPSCs and scaffolds were implanted subcutaneously in nude mice for 8 weeks. Harvested tissues were immunohistochemically stained for osteocalcin (OCN) expression from hDPSCs, and stained with alizarin red S for examination of their calcium deposition in vivo. RESULTS: The ISCS had no adverse effect on hDPSCs, promoted their proliferation, and significantly up-regulated the expression of osteogenesis-related genes and proteins. The hDPSCs co-cultured with ISCS in ODM exhibited the highest ALP activity and calcium deposition in vitro. The ISCS promoted the OCN expression and calcium deposition of hDPSCs after ectopic transplantation in vivo. CONCLUSIONS: Intrafibrillar-silicified collagen scaffolds significantly promoted the proliferation, osteogenic differentiation and mineralization of hDPSCs, when compared with NCS. This study demonstrates combining the use of hDPSCs and ISCS to promote bone-like tissue formation is a promising approach for clinical bone repair and regeneration.

[Effect of experimentally created occlusal disorders on the expression of estrogen in rat condylar cartilage].

OBJECTIVE: To investigate the effect of experimentally created occlusal disorders (ECOD) on the expression of estrogen in rat condylar cartilage. METHODS: The model of ECOD was created by moving right upper and left lower first molars anteriorly. The animals in ECOD were sacrificed at 2, 4, 6, 8 weeks later. In removed occlusal disorders group, the moved first molars were extracted at 6 weeks later, and the animals were sacrificed 2 weeks later. The expression of estrogen was detected by SABC technique of immunocytochemistry, and then was analyzed by the density of estrogen-positive chondrocytes. RESULTS: 1) Estrogen was abundant in mature layer and hypertrophic layer of rat mandibular condylar cartilage. 2) In control group, the expression of estrogen decreased gradually from 6-week-old to 16-week-old. 3) In both childhood and puberty rats, the expression of estrogen in experiment group was significantly higher at 2 weeks after treatment, while no difference was found at 4, 6, 8 weeks after treatment. However, the expression in removed occlusal disorder group was higher than that in control group and 8 weeks of ECOD group. CONCLUSION: In rat condylar cartilage, the expression of estrogen de-creases with age. Induced by ECOD, the expression of estrogen increases in early stage of remodelling activity.

[Spinal fusion of lumbar intertransverse process by using tissue engineered bone with xenogeneic deproteinized cancellous bone as scaffold].

OBJECTIVE: To study the properties of the xenogeneic deproteinized cancellous bone used as a scaffold in the bone tissue engineering and its application to the spinal fusion of the lumbar intertransverse process in a goat. METHODS: The deproteinized bone was derived from an adult pig's femoral cancellous bone through the physical and chemical treatments. Its morphological features, constituting components, and biomechanical properties were examined by the scanning electron microscopy, X-ray diffraction analysis, and mechanical experimental instrument. The cell-material complex was observed under the inverted phase contrast microscope to evaluate the adhesion and the growth of the osteoblasts. The experimental model of the spinal fusion of the lumbar intertransverse process was produced in 12 male goats aged 6-8 months, which were divided into two groups. In Group A, the tissue engineered bone constructed by the xenogeneic deproteinized cancellous bone, the recombinant human bone morphogenetic protein 2, and the mesenchymal stem cells was used for the spinal fusion; however, in Group B the auto-ilium was used. The samples were harvested at 4, 8 and 12 weeks postoperatively, and a series of examinations were performed, including the radiography and the histomorphological assay. RESULTS: The deproteinized cancellous bone had a natural pore network system, with an aperture ranging in size from 200 to 500 microm, containing a main organic material of collagen and the inorganic material of hydroxyapatite. So, the deproteinized cancellous bone had a good mechanical strength and a good histocompatibility. In Group A, the X-ray examination at different timepoints postoperatively showed that at 4 weeks, the bridging areas of all the fusion sites were not clear, especially on the internal side; at 8 weeks, the upper and lower bridged parts had a narrowed gap, with formation of much continuous bony callus; at 12 weeks, a complete fusion occurred. In the early stage, the material density was slightly lower in Group A than in Group B, but at 12 weeks the density was almost the same in both the groups. Histological examination in the transplant area showed that at 4 weeks in Group A there was a new bone formation in a multipoint way; at 8 weeks, a "sandwich-shaped" new bone was crossed with the transplanting materials; and at 12 weeks, a medullary cavity was remodeled and a new cancellous bone was formed. The osteogenic process of the tissue engineered bone constructed by the xenogeneic deproteinized cancellous bone scaffold was almost the same as the auto-ilium osteogenesis. CONCLUSION: The xenogeneic deproteinized cancellous bone is a good material in the bone tissue engineering, which can be used as an osteogenesis scaffold and provide a stable environment for revascularization and osteoblastic differentiation.

[Repair of upper tibial epiphyseal defect with engineered epiphyseal cartilage in rabbits].

OBJECTIVE: To observe the effect of engineered epiphyseal cartilage regenerated in vitro with 3-D scaffold by chondrocytes from epiphyseal plate in repairing the tibial epiphyseal defect, and to explore the methods to promote the confluence between engineered cartilage and epiphyseal plate. METHODS: Chondrocytes were isolated enzymatically from the epiphyseal plates of immature rabbits, and then planted into the tissue culture flasks and cultivated. The first passage chondrocytes were collected and mixed fully with the self-made liquid biological gel at approximately 2.5 x 10(7) cells/ml to form cell-gel fluid. The cell-gel fluid was dropped into the porous calcium polyphosphate fiber/poly-L-lactic acid(CPPf/PLLA)scaffold, and a cell-gel-scaffold complex formed after being solidified. The defect models of 40% upper tibial epiphyseal plate were made in 72 immature rabbits; they were divided into 4 groups: group A(the cell-gel-scaffold complex was transplanted into the defect and the gap filled with chondrocyte-gel fluid), group B (with noncell CPPf/PLLA scaffold), group C(with fat) and group D(with nothing). The changes of roentgenograph, gross and histology were investigated after 2, 4, 6, 8, 12 and 16 weeks of operation. RESULTS: In group A, the typical histological structure of epiphyseal plate derived from the engineered cartilage with a fine integration between host and donor tissues after 2 weeks. The repaired epiphyseal plate had normal histological structure without deformation of tibia after 4 weeks. The early histological change of epiphyseal closure appeared in the repaired area with varus and shortening deformation of the tibia after 8 weeks. The epiphyseal plate was closed in the repaired area with more evident deformation of tibia; the growth function of repaired epiphyseal plate was 43.6% of the normal one. In groups B, C and D, deformation of tibia occurred after 2 weeks; the defect area of epiphyseal plate was completely closed after 4 weeks. The deformation was very severe without growth of the injured epiphyseal plate after 16 weeks, and no significant difference was observed between the three groups. CONCLUSION: Engineered epiphyseal cartilage can repair the epiphyseal defect in the histological structure with partial recovery of the epiphyseal growth capability. Injecting the suspension of fluid chondrocyte-gel into the defects induces a fine integration of host and donor tissues.

[Chondrogenesis in vitro by epiphyseal chondrocytes seeding into three-dimensional scaffolds].

OBJECTIVE: To observe the efficiency and biological characteristics in regenerating in vitro tissue-engineered cartilage from epiphyseal chondrocyte-scaffold complex. METHODS: The first passage epiphyseal chondrocytes were collected and mixed with the biological gel-matrix, the chondrocyte-gel fluid was dropped into the scaffold to form a complex. The complexes were in vitro cultivated. The changes of complexes in morphology and synthesis of collagens type II and type I and aggrecan were observed under the gross and the inverted and light microscopes. The sulfate GAG content in complexes was measured by the the modified dimethylmethylene blue method. RESULTS: During cultivation, the complexes could keep its original shape with the stable homogeneous three-dimensional distribution of chondrocytes, gradually became milk white and translucence with their rigidity increasing. In the 1st week, the chondrocytic lacunae formed in the complexes. After 2 weeks, the complex was gradually reorganized into the mature engineered cartilage with rich collagen type II and aggrecan and typical cartilage histological structure, but with negative immunological staining of collagen type I. In the 4th week, the engineered cartilage resembled the nature epiphyseal plate in the characteristic of histological structure, and had over 34% of the sulfate GAG content of the natural epiphyseal plate. CONCLUSION: The epiphyseal chondrocyte-scaffold complex can be reorganized into typical cartilage with the epiphyseal-like histological structure, and be fit for repairing the epiphyseal defect. The tissue engineered cartilage cultivated for 1-2 weeks may be a good choice for repairing epiphyseal defect.