A cross-sectional study for prevalence and risk factors of peri-implant marginal bone loss.

STATEMENT OF PROBLEM: Progressive peri-implant marginal bone loss and peri-implantitis have become a growing problem, but cross-sectional studies on their prevalence and risk factors are sparse. PURPOSE: The purpose of this cross-sectional clinical study was to investigate the prevalence of peri-implant marginal bone loss (MBL) and to identify systemic and local risk factors. MATERIAL AND METHODS: All adult patients who had received dental implants at the National Taiwan University Hospital (NTUH) during 2009 or 2010 were included. Their medical records were collected from the NTUH-integrative Medical Database. Consecutive follow-up radiographs were accessed for severity of MBL. The influence of each factor on MBL was estimated by using generalized estimating equations (GEEs). RESULTS: A total of 732 participants with 1873 implants were analyzed (mean follow-up: 5.30 years). The prevalence of MBL was 59.15% at the individual level and 49.55% at the implant level. The risk indicators identified for the presence of MBL were follow-up period of more than 2 years, diagnosis of diabetes within 12 months, radiation therapy (2 years after implant placement), implant location at maxillary canine (compared with mandibular molar), and implants from the Nobel Biocare brands (Brånemark System and NobelActive). A second multivariate GEE model confirmed the association of progressive MBL with implant location at the maxillary canine and mandibular incisor and implant brand or design. CONCLUSIONS: The identified risk indicators for MBL were longer follow-up period, diagnosis of diabetes, radiation therapy, implant location at maxillary canine, and implant brand or design.

Cyclic mechanical stretch regulates the AMPK/Egr1 pathway in tenocytes via Ca2+-mediated mechanosensing.

PURPOSE: Mechanical stimuli are essential for the maintenance of tendon tissue homeostasis. The study aims to elucidate the mechanobiological mechanisms underlying the maintenance of tenocyte homeostasis by cyclic mechanical stretch under high-glucose (HG) condition. MATERIALS AND METHODS: Primary tenocytes were isolated from rat Achilles tendon and 2D-cultured under HG condition. The in vitro effects of a single bout, 2-h cyclic biaxial stretch session (1 Hz, 8%) on primary rat tenocytes were explored through Flexcell system. Cell viability, tenogenic gene expression, intracellular calcium concentration, focal adhesion kinase (FAK) expression, and signaling pathway activation were analyzed in tenocytes with or without mechanical stretch. RESULTS: Mechanical stretch increased tenocyte proliferation and upregulated early growth response protein 1 (Egr1) expression. An increase in intracellular calcium was observed after 30 min of stretching. Mechanical stretch phosphorylated FAK, calmodulin-dependent protein kinase kinase 2 (CaMKK2), and 5' adenosine monophosphate-activated protein kinase (AMPK) in a time-dependent manner, and these effects were abrogated after blocking intracellular calcium. Inhibition of FAK, CaMKK2, and AMPK downregulated the expression of Egr1. In addition, mechanical stretch reinforced cytoskeletal organization via calcium (Ca2+)/FAK signaling. CONCLUSIONS: Our study demonstrated that mechanical stretch-induced calcium influx activated CaMKK2/AMPK signaling and FAK-cytoskeleton reorganization, thereby promoting the expression of Egr1, which may help maintain tendon cell characteristics and homeostasis in the context of diabetic tendinopathy.

Restoration of a wide edentulous posterior site with two small-diameter implants: Biologically-driven alternative treatment.

BACKGROUND/PURPOSE: Crestal bone stability, implant rigidity and occlusal loading are issues with small-diameter implants. This article demonstrates the use of two small-diameter implants replacing a missing wide edentulous site and discusses factors that may affect bone changes. METHODS: Patients who wanted to restore an edentulous space measuring from 12 to 14 mm wide in the posterior region were offered an alternative treatment option, using two narrow or regular-diameter implants instead of one wide implant. In the study, the crestal bone stability of 12 implants in 6 edentulous sites was assessed by cone beam CTs and periapical radiographs in follow-up visits for up to 4 years. RESULTS: The bone level of all the implants was stable at buccal, lingual, mesial and distal sites, with mean values < 1 mm. The average buccal bone thickness was 1.15 ± 1.07 mm and lingual was 1.86 ± 0.89 mm, meaning that implants were surrounded by a sufficient amount of bone. The good treatment outcome may be attributed to the capability of fabricating better emergence profiles, angles (Mean: 20.67 ± 7.82° at the mesial and 20.25 ± 8.23° at the distal site) and cleansable embrasures of prostheses which are key to maintaining good oral hygiene and implant health. CONCLUSION: Using two narrow or regular-diameter implants to replace a single edentulous site measured around 12-14 mm wide in posterior region seemed to be a feasible treatment option. It is especially suitable for sites with ridge atrophy and/or patients suffering from systemic diseases.

Metformin-Incorporated Gelatin/Nano-Hydroxyapatite Scaffolds Promotes Bone Regeneration in Critical Size Rat Alveolar Bone Defect Model.

In this study, we fabricated gelatin/nano-hydroxyapatite/metformin scaffold (GHMS) and compared its effectiveness in bone regeneration with extraction-only, Sinbone, and Bio-Oss Collagen® groups in a critical size rat alveolar bone defect model. GHMS was synthesized by co-precipitating calcium hydroxide and orthophosphoric acid within gelatin solution, incorporating metformin, and cross-linked by microbial transglutaminase. The morphology, characterization, and biocompatibility of scaffold were examined. The in vitro effects of GHMS on osteogenic gene and protein expressions were evaluated. In vivo bone formation was assessed in a critical size rat alveolar bone defect model with micro-computed tomography and histological examination by comparing GHMS with extraction-only, Sinbone, and Bio-Oss Collagen®. The synthesized GHMS had a highly interconnected porous structure with a mean pore size of 81.85 ± 13.8 µm. GHMS exhibited good biocompatibility; promoted ALPL, RUNX2, SP7, BGLAP, SPARC and Col1a1 gene expressions; and upregulated the synthesis of osteogenic proteins, including osteonectin, osteocalcin, and collagen type I. In critical size rat alveolar bone defects, GHMS showed superior bone regeneration compared to extraction-only, Sinbone, and Bio-Oss Collagen® groups as manifested by greater alveolar ridge preservation, while more bone formation with a lower percentage of connective tissue and residual scaffold at the defect sites grafted with GHMS in histological staining. The GHMS presented in this study may be used as a potential bone substitute to regenerate alveolar bone. The good biocompatibility, relatively fast degradation, interconnected pores allowing vascularization, and higher bioactivity properties of the components of the GHMS (gelatin, nHA, and metformin) may contribute to direct osteogenesis.

Biocompatibility and Biological Performance of Additive-Manufactured Bioabsorbable Iron-Based Porous Interference Screws in a Rabbit Model: A 1-Year Observational Study.

This study evaluated the mid-term (12-month) biomechanical, biocompatibility, and biological performance of additive-manufactured bioabsorbable iron-based interference screws (ISs). Two bioabsorbable iron IS types-manufactured using pure iron powder (iron_IS) and using pure iron powder with 0.2 wt% tricalcium phosphate (TCP_IS)-were compared with conventional metallic IS (control) using in vitro biocompatibility and degradation analyses and an in vivo animal study. The in vitro ultimate failure strength was significantly higher for iron_IS and TCP_IS than for control ISs at 3 months post-operatively; however, the difference between groups were nonsignificant thereafter. Moreover, at 3 months after implantation, iron_IS and TCP_IS increased bone volume fraction, bone surface area fraction, and percent intersection surface; the changes thereafter were nonsignificant. Iron_IS and TCP_IS demonstrated degradation over time with increased implant surface, decreased implant volume, and structure thickness; nevertheless, the analyses of visceral organs and biochemistry demonstrated normal results, except for time-dependent iron deposition in the spleen. Therefore, compared with conventional ISs, bioabsorbable iron-based ISs exhibit higher initial mechanical strength. Although iron-based ISs demonstrate high biocompatibility 12 months after implantation, their corrosive iron products may accumulate in the spleen. Because they demonstrate mechanical superiority along with considerable absorption capability after implantation, iron-based ISs may have potential applications in implantable medical-device development in the future.

Morphology of Peri-Implant Tissues Around Permanent Prostheses With Various Emergence Angles Following Free Gingival Grafting.

PURPOSE: To analyze the tissue morphology around implant-supported prostheses by digital technology and to evaluate the effect of prosthetic contours on the changes in tissues following the free gingiva graft procedure. MATERIAL AND METHODS: A total of 53 implants in 32 patients receiving free gingiva grafts were selected. These had previously presented insufficient keratinized mucosa width (KMW). At the follow-up visits (mean: 16.66 ± 9.97 months), the implant position and tissue condition were documented with an oral scanner. Vertical soft tissue thickness (VT), measured from the implant-abutment connection to the marginal tissues, and horizontal soft tissue thickness (HT), at the level of the platform, were calculated. The VT, HT, and emergence angle (EA) of prostheses were assessed by 3Shape analyzing software. The final KMW was measured by clinical assessment. Marginal bone loss (MBL) was calculated in the follow-up bitewing radiographs. RESULTS: The mean VT in the study was 2.65 ± 0.75 mm at the mid-buccal sites, 3.74 ± 1.22 mm at the mesial, 3.16 ± 1.08 mm at the distal, and 2.53 ± 0.92 at the mid-lingual aspects. The mid-buccal HT was 1.45 ± 0.53 mm while the mid-lingual was 1.05 ± 0.43 mm (p = 0.008). Interestingly, prostheses with mid-buccal EA > $\; > \;$ 30° exhibited slightly lower VT, but higher HT, than the ones with EA ≤ $\; \le \;$ 30°. Prostheses with proximal EA > 30° displayed slightly more MBL, compared to prostheses with EA ≤ $\; \le \;$ 30°. The mean KMW was 4.08 ± 1.10 mm. CONCLUSIONS: Free gingival grafting is a predictable treatment approach to augmenting soft tissue 3-dimensionally. Prostheses with EA ≤ $\; \le \;$ 30° were preferable for preserving the maximal VT and maintaining crestal bone stability.

Biocompatibility and Biological Performance Evaluation of Additive-Manufactured Bioabsorbable Iron-Based Porous Suture Anchor in a Rabbit Model.

This study evaluated the biocompatibility and biological performance of novel additive-manufactured bioabsorbable iron-based porous suture anchors (iron_SAs). Two types of bioabsorbable iron_SAs, with double- and triple-helical structures (iron_SA_2_helix and iron_SA_3_helix, respectively), were compared with the synthetic polymer-based bioabsorbable suture anchor (polymer_SAs). An in vitro mechanical test, MTT assay, and scanning electron microscope (SEM) analysis were performed. An in vivo animal study was also performed. The three types of suture anchors were randomly implanted in the outer cortex of the lateral femoral condyle. The ultimate in vitro pullout strength of the iron_SA_3_helix group was significantly higher than the iron_SA_2_helix and polymer_SA groups. The MTT assay findings demonstrated no significant cytotoxicity, and the SEM analysis showed cells attachment on implant surface. The ultimate failure load of the iron_SA_3_helix group was significantly higher than that of the polymer_SA group. The micro-CT analysis indicated the iron_SA_3_helix group showed a higher bone volume fraction (BV/TV) after surgery. Moreover, both iron SAs underwent degradation with time. Iron_SAs with triple-helical threads and a porous structure demonstrated better mechanical strength and high biocompatibility after short-term implantation. The combined advantages of the mechanical superiority of the iron metal and the possibility of absorption after implantation make the iron_SA a suitable candidate for further development.

3D laser-printed porous Ti6Al4V dental implants for compromised bone support.

BACKGROUND/PURPOSE: Alveolar bone loss following peri-implantitis remains a clinical challenge. We aimed to design a novel bioactive dental implant to accommodate the large bone defect caused by removal of previously failed implant. METHODS: Bio-ActiveITRI dental implant was manufactured with laser-sintered additive 3D printing technique. A 7.5 mm diameter × 7.0 mm depth osteotomy defect was created at the lateral aspect of distal femur of 20 New Zealand white rabbits to simulate the bony defect after removal of failed dental implant. One side of distal femurs was randomly selected for the commercially pure titanium NobelActive™ implant (control group) and the other side with Bio-ActiveITRI Ti6Al4V porous dental implant (ITRI group). Animals were sacrificed at 4, 8 and 12 weeks after the implants' insertion. The samples were processed for gross morphological analysis, radiographic examination, micro-CT evaluation, and mechanical testing. RESULTS: In histomorphometrical evaluation and micro-CT analysis, active new bone formation and good osseointegration within the ITRI implants were observed at the bone gap surrounding the dental implants. The biomechanical parameters in the Bio-ActiveITRI dental implants were significantly higher than those of the commercially control samples. For the Bio-ActiveITRI dental implants, the trabecular thickness decreased, while the trabecular separation and total porosity increased from the prescribed 1-month to 3-month time points; reflecting the natural remodeling of surrounding bony tissue in the Bio-ActiveITRI dental implants. CONCLUSION: The novel porous structured Bio-ActiveITRI dental implants may have a great potential for the prosthetic reconstruction where bone support is compromised after removal of a previously failed implant.

A Dynamic Hanging-Drop System for Mesenchymal Stem Cell Culture.

There have been many microfluid technologies combined with hanging-drop for cell culture gotten developed in the past decade. A common problem within these devices is that the cell suspension introduced at the central inlet could cause a number of cells in each microwell to not regularize. Also, the instability of droplets during the spheroid formation remains an unsolved ordeal. In this study, we designed a microfluidic-based hanging-drop culture system with the design of taper-tube that can increase the stability of droplets while enhancing the rate of liquid exchange. A ring is surrounding the taper-tube. The ring can hold the cells to enable us to seed an adequate amount of cells before perfusion. Moreover, during the period of cell culture, the mechanical force around the cell is relatively low to prevent stem cells from differentiate and maintain the phenotype. As a result of our hanging system design, cells are designed to accumulate at the bottom of the droplet. This method enhances convenience for observation activities and analysis of experiments. Thus, this microfluid chip can be used as an in vitro platform representing in vivo physiological conditions, and can be useful in regenerative therapy.

Biomimetic Synthesis of Nanocrystalline Hydroxyapatite Composites: Therapeutic Potential and Effects on Bone Regeneration.

The development of a novel alloplastic graft with both osteoinductive and osteoconductive properties is still necessary. In this study, we tried to synthesize a biomimetic hydroxyapatite microspheres (gelatin/nano-hydroxyapatite microsphere embedded with stromal cell-derived factor-1: GHM-S) from nanocrystalline hydroxyapatites and to investigate their therapeutic potential and effects on bone regeneration. In this study, hydroxyapatite was synthesized by co-precipitation of calcium hydroxide and orthophosphoric acid to gelatin solution. The microbial transglutaminase was used as the agent to crosslink the microspheres. The morphology, characterization, and thermal gravimetric analysis of microspheres were performed. SDF-1 release profile and in vitro biocompatibility and relative osteogenic gene expression were analyzed, followed by in vivo micro-computed tomography study and histological analysis. The synthesized hydroxyapatite was found to be similar to hydroxyapatite of natural bone tissue. The stromal cell-derived factor-1 was embedded into gelatin/hydroxyapatite microsphere to form the biomimetic hydroxyapatite microsphere. The stromal cell-derived factor-1 protein could be released in a controlled manner from the biomimetic hydroxyapatite microsphere and form a concentration gradient in the culture environment to attract the migration of stem cells. Gene expression and protein expression indicated that stem cells could differentiate or develop into pre-osteoblasts. The effect of bone formation by the biomimetic hydroxyapatite microsphere was assessed by an in vivo rats' alveolar bone defects model and confirmed by micro-CT imaging and histological examination. Our findings demonstrated that the biomimetic hydroxyapatite microsphere can enhance the alveolar bone regeneration. This design has potential be applied to other bone defects.

Comparison of complaints to the intensive care units and those to the general wards: an analysis using the Healthcare Complaint Analysis Tool in an academic medical center in Taiwan.

BACKGROUND: The management of complaints in the setting of intensive care may provide opportunities to understand patient and family experiences and needs. However, there are limited reports on the structured application of complaint analysis tools and comparisons between healthcare complaints in the critical care setting and other settings. METHODS: From the complaint management database of a university-affiliated medical center in Taiwan, we retrospectively identified the records of healthcare complaints to the intensive care units (ICUs) from 2008 to 2016. Complaints to the general wards in the same period were randomly selected from the database with twice the number of that of the ICU complaints. We coded, typed, and compared the complaints from the two settings according to the Healthcare Complaint Analysis Tool. RESULTS: We identified 343 complaints to the ICUs and randomly selected 686 complaints to the general wards during the 9-year study period. Most (94.7%) of the complaints to the ICUs came from the family members, whereas more complaints to the general wards came from the patients (44.2%). A total of 1529 problems (441 from ICU and 818 from general wards) were identified. Compared with the general ward complaints, in the ICU there were more complaints with multiple problems (25.1% vs. 16.9%, p = 0.002), complaints were referred more frequently to the nurses (28.1% vs. 17.5%, p < 0.001), and they focused more commonly on the care on the ICU/ward (60.5% vs. 54.2%, p = 0.029). The proportions of the three domains (clinical, management, and relationship) of complaints were similar between the ICU and general ward complaints (p = 0.121). However, in the management domain, the problems from ICU complaints focused more on the environment than on the institutional processes (90.9% vs. 74.5%, p < 0.001), whereas in the relationship domain, the problems focused more on communication (17.9% vs. 8.0%) and less on listening (34.6% vs. 46.5%) (p = 0.002) than the general ward complaints. CONCLUSIONS: A structured typing and systematic analysis of the healthcare complaints to the ICUs may provide valuable insights into the improvement of care quality, especially to the perceptions of the ICU environment and communications of the patients and their families.

Magnetic hyperthermia enhance the treatment efficacy of peri-implant osteomyelitis.

BACKGROUND: When bacteria colony persist within a biofilm, suitable drugs are not yet available for the eradication of biofilm-producing bacteria. The aim of this study is to study the effect of magnetic nano-particles-induced hyperthermia on destroying biofilm and promoting bactericidal effects of antibiotics in the treatment of osteomyelitis. METHODS: Sixty 12-weeks-old male Wistar rats were used. A metallic 18G needle was implanted into the bone marrow cavity of distal femur after the injection of Methicillin-sensitive Staphylococcus aureus (MSSA). All animals were divided into 5 different treatment modalities. The microbiological evaluation, scanning electron microscope examination, radiographic examination and then micro-CT evaluation of peri-implant bone resorption were analyzed. RESULTS: The pathomorphological characteristics of biofilm formation were completed after 40-days induction of osteomyelitis. The inserted implants can be heated upto 75 °C by magnetic heating without any significant thermal damage on the surrounding tissue. We also demonstrated that systemic administration of vancomycin [VC (i.m.)] could not eradicate the bacteria; but, local administration of vancomycin into the femoral canal and the presence of magnetic nanoparticles hyperthermia did enhance the eradication of bacteria in a biofilm-based colony. In these two groups, the percent bone volume (BV/TV: %) was significantly higher than that of the positive control. CONCLUSIONS: For the treatment of chronic osteomyelitis, we developed a new modality to improve antibiotic efficacy; the protection effect of biofilms on bacteria could be destroyed by magnetic nanoparticles-induced hyperthermia and therapeutic effect of systemic antibiotics could be enhanced.

Hyperglycemia Augments the Adipogenic Transdifferentiation Potential of Tenocytes and Is Alleviated by Cyclic Mechanical Stretch.

Diabetes mellitus is associated with damage to tendons, which may result from cellular dysfunction in response to a hyperglycemic environment. Tenocytes express diminished levels of tendon-associated genes under hyperglycemic conditions. In contrast, mechanical stretch enhances tenogenic differentiation. However, whether hyperglycemia increases the non-tenogenic differentiation potential of tenocytes and whether this can be mitigated by mechanical stretch remains elusive. We explored the in vitro effects of high glucose and mechanical stretch on rat primary tenocytes. Specifically, non-tenogenic gene expression, adipogenic potential, cell migration rate, filamentous actin expression, and the activation of signaling pathways were analyzed in tenocytes treated with high glucose, followed by the presence or absence of mechanical stretch. We analyzed tenocyte phenotype in vivo by immunohistochemistry using an STZ (streptozotocin)-induced long-term diabetic mouse model. High glucose-treated tenocytes expressed higher levels of the adipogenic transcription factors PPARγ and C/EBPs. PPARγ was also highly expressed in diabetic tendons. In addition, increased adipogenic differentiation and decreased cell migration induced by high glucose implicated a fibroblast-to-adipocyte phenotypic change. By applying mechanical stretch to tenocytes in high-glucose conditions, adipogenic differentiation was repressed, while cell motility was enhanced, and fibroblastic morphology and gene expression profiles were strengthened. In part, these effects resulted from a stretch-induced activation of ERK (extracellular signal-regulated kinases) and a concomitant inactivation of Akt. Our results show that mechanical stretch alleviates the augmented adipogenic transdifferentiation potential of high glucose-treated tenocytes and helps maintain their fibroblastic characteristics. The alterations induced by high glucose highlight possible pathological mechanisms for diabetic tendinopathy. Furthermore, the beneficial effects of mechanical stretch on tenocytes suggest that an appropriate physical load possesses therapeutic potential for diabetic tendinopathy.

Tissue transglutaminase is involved in mechanical load-induced osteogenic differentiation of human ligamentum flavum cells.

Mechanical load-induced osteogenic differentiation might be the key cellular event in the calcification and ossification of ligamentum flavum. The aim of this study was to investigate the influence of tissue transglutaminase (TGM2) on mechanical load-induced osteogenesis of ligamentum flavum cells. Human ligamentum flavum cells were obtained from 12 patients undergoing lumbar spine surgery. Osteogenic phenotypes of ligamentum flavum cells, such as alkaline phosphatase (ALP), Alizarin red-S stain, and gene expression of osteogenic makers were evaluated following the administration of mechanical load and BMP-2 treatment. The expression of TGM2 was evaluated by real-time PCR, Western blotting, and enzyme-linked immunosorbent assay (ELISA) analysis. Our results showed that mechanical load in combination with BMP-2 enhanced calcium deposition and ALP activity. Mechanical load significantly increased ALP and OC gene expression on day 3, whereas BMP-2 significantly increased ALP, OPN, and Runx2 on day 7. Mechanical load significantly induced TGM2 gene expression and enzyme activity in human ligamentum flavum cells. Exogenous TGM2 increased ALP and OC gene expression; while, inhibited TG activity significantly attenuated mechanical load-induced and TGM2-induced ALP activity. In summary, mechanical load-induced TGM2 expression and enzyme activity is involved in the progression of the calcification of ligamentum flavum.

Low-intensity pulsed ultrasound stimulates matrix metabolism of human annulus fibrosus cells mediated by transforming growth factor ß1 and extracellular signal-regulated kinase pathway.

PURPOSE: There are limited strategies to restore the damaged annulus fibrosus (AF) of the intervertebral disc. Low-intensity pulsed ultrasound (LIPUS) has positive effects on the proliferation of several types of cells and the repair of damage tissue in vivo. However, scientific evidence of therapeutic effects of LIPUS on AF cells remains limited. The purpose of this study is to evaluate the feasibility of applying LIPUS to the repair of the AF. MATERIALS AND METHODS: We used an in vitro model of human AF cells subjected to LIPUS stimulation to examine its effects on cell proliferation and matrix metabolism. Cell viability, synthesis of collagen and glycosaminoglycan (GAG), expression of matrix metalloproteinases (MMPs) and transforming growth factor ß1 and pathways involving mitogen-activated protein kinases (MAPKs) were investigated. RESULTS: LIPUS significantly enhanced proliferation of AF cells after 5 days of treatment. LIPUS with an intensity of 0.5 W/cm(2) increased the collagen and GAG synthesis and decreased the expressions of MMP-1 and -3 of human AF cells. Real-time polymerase chain reactions and western blotting analysis revealed that LIPUS could increase transforming growth factor ß1 (TGF-ß1) and activate extracellular signal-regulated kinase (ERK) pathway. In addition, TGF-ß receptor kinase inhibitor could suppress the ultrasound-induced alterations in cell viability and matrix metabolism. CONCLUSIONS: The findings suggested that LIPUS could be useful as a physical stimulation of cell metabolism for the repair of the AF.

In situ forming hydrogel composed of hyaluronate and polygalacturonic acid for prevention of peridural fibrosis.

Hyaluronic acid-based hydrogels can reduce postoperative adhesion. However, the long-term application of hyaluronic acid is limited by tissue mediated enzymatic degradation. To overcome this limitation, we developed a polygalacturonic acid and hyaluronate composite hydrogel by Schiff's base crosslinking reaction. The polygalacturonic acid and hyaluronate composite hydrogels had short gelation time (less than 15 s) and degraded by less than 50 % in the presence of hyaluronidase for 7 days. Cell adhesion and migration assays showed polygalacturonic acid and hyaluronate composite hydrogels prevented fibroblasts from adhesion and infiltration into the hydrogels. Compared to hyaluronate hydrogels and commercial Medishield™ gels, polygalacturonic acid and hyaluronate composite hydrogel was not totally degraded in vivo after 4 weeks. In the rat laminectomy model, polygalacturonic acid and hyaluronate composite hydrogel also had better adhesion grade and smaller mean area of fibrous tissue formation over the saline control and hyaluronate hydrogel groups. Polygalacturonic acid and hyaluronate composite hydrogel is a system that can be easy to use due to its in situ cross-linkable property and potentially promising for adhesion prevention in spine surgeries.

Radix Scrophulariae extracts (harpagoside) suppresses hypoxia-induced microglial activation and neurotoxicity.

BACKGROUND: Hypoxia could lead to microglia activation and inflammatory mediators' overproduction. These inflammatory molecules could amplify the neuroinflammatory process and exacerbate neuronal injury. The aim of this study is to find out whether harpagoside could reduce hypoxia-induced microglia activation. METHODS: In this study, primary microglia cells harvested from neonatal ICR mice were activated by exposure to hypoxia (1 % O2 for 3 h). Harpagoside had been shown to be no cytotoxicity on microglia cells by MTT assay. The scavenger effect of harpagoside on hypoxia-enhanced microglial cells proliferation, associated inflammatory genes expression (COX-II, IL-1ß and IL-6 genes) and NO synthesis were also examined. RESULTS: Hypoxia enhances active proliferation of microglial cells, while harpagoside can scavenge this effect. We find that harpagoside could scavenge hypoxia-enhanced inflammatory genes expression (COX-2, IL-1ß and IL-6 genes) and NO synthesis of microglial cells. Under 3 h' hypoxic stimulation, the nuclear contents of p65 and hypoxia inducible factor-1α (HIF-1α) significantly increase, while the cytosol IκB-α content decreases; these effects can be reversed by 1 h's pre-incubation of 10(-8) M harpagoside. Harpagoside could decrease IκB-α protein phosphorylation and inhibit p65 protein translocation from the cytosol to the nucleus, thus suppress NF-κB activation and reduce the HIF-1α generation. CONCLUSION: These results suggested that the anti-inflammatory mechanism of harpagoside might be associated with the NF-κB signaling pathway. Harpagoside protect against hypoxia-induced toxicity on microglial cells through HIF-α pathway.

Arthropod steroid hormone (20-Hydroxyecdysone) suppresses IL-1ß-induced catabolic gene expression in cartilage.

BACKGROUND: In osteoarthritis (OA), the imbalance of chondrocytes' anabolic and catabolic factors can induce cartilage destruction. Interleukin-1 beta (IL-1ß) is a potent pro-inflammatory cytokine that is capable of inducing chondrocytes and synovial cells to synthesize MMPs. The hypoxia-inducible factor-2alpha (HIF-2alpha, encoded by Epas1) is the catabolic transcription factor in the osteoarthritic process. The purpose of this study is to validate the effects of ecdysteroids (Ecd) on IL-1ß-induced cartilage catabolism and the possible role of Ecd in treatment or prevention of early OA. METHODS: Chondrocytes and articular cartilage was harvested from newborn ICR mice. Ecd effect on chondrocytes viability was tested and the optimal concentration was determined by MTT assay. The effect of HIF-2α (EPAS1) in cartilage catabolism simulated by IL-1ß (5 ng/ml) was evaluated by articular cartilage explants culture. The effects of Ecd on IL-1ß-induced inflammatory conditions and their related catabolic genes expression were analyzed. RESULTS: Interleukin-1ß (IL-1ß) treatment on primary mouse articular cartilage explants enhanced their Epas1, matrix metalloproteinases (MMP-3, MMP-13) and ADAMTS-5 genes expression and down-regulated collagen type II (Col2a1) gene expression. With the pre-treatment of 10(-8) M Ecd, the catabolic effects of IL-1ß on articular cartilage were scavenged. CONCLUSION: In conclusions, Ecd can reduce the IL-1ß-induced inflammatory effect of the cartilage. Ecd may suppress IL-1ß-induced cartilage catabolism via HIF-2α pathway.

Second messengers mediating the proliferation and collagen synthesis of tenocytes induced by low-level laser irradiation.

For decades, low-level laser therapy (LLLT) has widespread applications in tendon-related injuries. Although the therapeutic effect of LLLT could be explained by photostimulation of target tissue and cells, how tenocytes sense photonic energy and convert them into cascades of cellular and molecular events is still not well understood. This study was designed to elucidate the effects of LLLT on cell proliferation and collagen synthesis by examining the associated second messengers including ATP, Ca(2+), and nitric oxide using rat Achilles tenocytes. Moreover, proliferating cell nuclear antigen (PCNA) and transforming growth factor-ß1 (TGF-ß1) related to cell proliferation and matrix metabolism were also studied. The results showed that 904 nm GaAs laser of 1 J/cm(2) could significantly increase the MTT activity and collagen synthesis of tenocytes. Second messengers including ATP and intracellular Ca2+ were increased after laser treatment. Quantitative PCR analysis of tenocytes treated with laser revealed up-regulated expression of PCNA, type I collagen, and TGF-ß1. Besides, laser-induced TGF-ß1 expression was significantly inhibited by extracellular signal-regulated kinase (ERK) specific inhibitor (PD98059). The findings suggested that LLLT stimulated ATP production and increased intracellular calcium concentration. Directly or indirectly via production of TGF-ß1, these second messengers mediated the proliferation of tenocytes and synthesis of collagen.