An injectable and thermosensitive hydrogel: Promoting periodontal regeneration by controlled-release of aspirin and erythropoietin.

Periodontitis is an inflammatory disease induced by complex interactions between host immune system and plaque microorganism. Alveolar bone resorption caused by periodontitis is considered to be one of the main reasons for tooth loss in adults. To terminate the alveolar bone resorption, simultaneous anti-inflammation and periodontium regeneration is required, which has not appeared in the existing methods. In this study, chitosan (CS), ß-sodium glycerophosphate (ß-GP), and gelatin were used to prepare an injectable and thermosensitive hydrogel, which could continuously release aspirin and erythropoietin (EPO) to exert pharmacological effects of anti-inflammation and tissue regeneration, respectively. The releasing profile showed that aspirin and EPO could be continuously released from the hydrogels, which exhibited no toxicity both in vitro and in vivo, for at least 21 days. Immunohistochemistry staining and micro-CT analyses indicated that administration of CS/ß-GP/gelatin hydrogels loaded with aspirin/EPO could terminate the inflammation and recover the height of the alveolar bone, which is further confirmed by histological observations. Our results suggested that CS/ß-GP/gelatin hydrogels are easily prepared as drug-loading vectors with excellent biocompatibility, and the CS/ß-GP/gelatin hydrogels loaded with aspirin/EPO are quite effective in anti-inflammation and periodontium regeneration, which provides a great potential candidate for periodontitis treatment in the dental clinic. Statement of Significance To terminate the alveolar bone resorption caused by periodontitis, simultaneous anti-inflammation and periodontium regeneration is required, which has not appeared in the existing methods. Here, (1) the chitosan (CS)/ß-sodium glycerophosphate/gelatin hydrogels loaded with aspirin/erythropoietin (EPO) can form at body temperature in 5 min with excellent biocompatibility in vitro and in vivo; (2) The faster release of aspirin than EPO in the early stage is beneficial for anti-inflammation and provides a microenvironment for ensuring the regeneration function of EPO in the following step. In vivo experiments revealed that the hydrogels are effective in the control of inflammation and regeneration of the periodontium. These results indicate that our synthesized hydrogels have a great potential in the future clinical application.

N-Acetyl-l-leucine-polyethylenimine-mediated miR-34a delivery improves osteogenesis and bone formation in vitro and in vivo.

Oral bone defects are difficult to treat. Recently, endogenous miR-34a was shown to be involved in bone anabolism. Clinical application of such microRNAs requires the inherent instability of microRNAs to be overcome by an efficient delivery system. In this study, we employed N-acetyl-l-leucine-modified polyethylenimine (N-Ac-l-Leu-PEI) as an miR-34a carrier and evaluated its delivery ability, transfection efficiency, cytotoxicity and whether it enhanced osteogenic differentiation and bone formation in vitro and in vivo. Stable N-Ac-l-Leu-PEI/miR-34a nanocomplexes were synthesized at a mass ratio of 4 and had a small size (190.34 nm), a low zeta potential (21.1 mV), a high transfection efficiency (69.39%) and no cytotoxicity in MG63 cells. N-Ac-l-Leu-PEI-mediated miR-34a delivery in vitro promoted ALP activity and expression of osteogenic differentiation markers, Runx2, SP7 and ColI to higher levels than those produced by Lipofectamine 2000-mediated delivery. N-Ac-l-Leu-PEI also achieved delivery of miR-34a in vivo to a local cranial bone defect area with miR-34a retaining the ability to initiate significant new bone formation 12 weeks post-implantation. This demonstrates the potential for N-Ac-l-Leu-PEI as a gene therapy vehicle for the regeneration of bone defects.

Aspirin-Based Carbon Dots, a Good Biocompatibility of Material Applied for Bioimaging and Anti-Inflammation.

The emerging photoluminescent carbon-based nanomaterials are promising in various fields besides cell imaging and carrier transport. Carbon nanomaterials with specific biological functions, however, are rarely investigated. Aspirin is a very common anti-inflammatory medication to relieve aches and pains. In this study, we have tried to create a carbon nanoparticle with aspirin, and we expect that this new carbon nanoparticle will have both anti-inflammatory and fluorescent biomarker functions. Fluorescent aspirin-based carbon dots (FACDs) were synthesized by condensing aspirin and hydrazine through a one-step microwave-assisted method. Imaging data demonstrated that FACDs efficiently entered into human cervical carcinoma and mouse monocyte macrophage cells in vitro with low cell toxicity. Results from quantitative polymerase chain reaction and histological analysis indicated that FACDs possessed effective anti-inflammatory effects in vitro and in vivo compared to aspirin only. Hematology, serum biochemistry, and histology results suggested that FACDs also had no significant toxicity in vivo. Our results clearly demonstrate that FACDs have dual functions, cellular imaging/bioimaging and anti-inflammation, and suggest that FACDs have great potential in future clinical applications.

An oligodeoxynucleotide that induces differentiation of bone marrow mesenchymal stem cells to osteoblasts in vitro and reduces alveolar bone loss in rats with periodontitis.

To investigate the effect of oligodeoxynucleotides (ODNs) on the differentiation of rat bone marrow mesenchymal stem cells (BMSCs) to osteoblasts, in order to find a candidate ODN with potential for the treatment of periodontitis, a series of ODNs were designed and selected to test their effect on the promotion of the differentiation of BMSCs to osteoblasts in vitro and on the repair of periodontal tissue in rats with periodontitis. It was found that MT01, one of the ODNs with the sequences of human mitochondrial DNA, stimulated the proliferation of BMSCs, the differentiation of BMSCs to osteoblasts and mRNA expression of bone-associated factors including Runx2, Osterix, OPG, RANKL and collagen I in vitro. In vivo study showed that MT01 prevented the loss of alveolar bone in the rats with periodontitis and induced the production of proteins of OPG and Osterix in the bone tissue. These results indicated that MT01 could induce differentiation of BMSCs to osteoblasts and inhibit the alveolar bone absorption in rats with periodontitis.

[The effect of basic fibroblast growth factor on the gene expression of syndecan-4 by human periodontal ligament cell in culture].

OBJECTIVE: To study the effect of basic fibroblast growth factor (bFGF) on the gene expression of syndecan-4 by human periodontal ligament cell (PDLC) in culture, and discuss the effect of bFGF on human PDLC proliferation and migration. METHODS: 68 adolescent (12-18 years old) health premolar were collected, which were extracted for orthodontic reason. Human PDLC were cultured and stimulated by exogenous bFGF. After cultured 24, 48, 72h, gene expression of syndecan-4 was detected by SYBR green quantitative real time polymerase chain reaction. RESULTS: The mRNA expression of syndecan-4 in 24 h group increased markedly than that in control group (P < 0.01), expecially in 1.0 ng x mL(-1) group. 1.0 ng x mL(-1) group in 48 h higher than that control group (P < 0.05). 1.0 ng x mL(-1) group in 72h compared with control group was lower (P < 0.05). CONCLUSION: The mRNA expression of syndecan-4 was increased by bFGF at the beginning, but the expression was decreased with the time. The expression of such changes may be one of the important factors which participate in the migration process of PDLC.

[The effect of basic fibroblast growth factor on the mRNA expression of beta1 integrin subunit by periodontal ligament fibroblasts in culture].

OBJECTIVE: To study the effect of basic fibroblast growth factor on the mRNA expression of beta1 integrin subunit by periodontal ligament fibroblasts in culture; to discuss the effect of basic fibroblast growth factor in periodontal regeneration. METHODS: Human periodontal ligament fibroblasts were cultured and stimulated by basic fibroblast growth factor (0.1, 1.0, 10.0 ng x mL(-1)) for 24, 48, 72 h respectively, and then mRNA expression of beta1 integrin subunit was assessed by fluorescent quantitative real-time reverse transcription polymerase chain reaction. RESULTS: Basic fibroblast growth factor enhanced the mRNA expression of beta1 integrin subunit, and there was optimal effect when the concentration of basic fibroblast growth factor was 1.0 ng x mL(-1) at 24, 48, 72 h respectively; the mRNA expression of beta1 integrin subunit at 72 h was higher than that at 24, 48 h. CONCLUSION: Basic fibroblast growth factor can strengthen human periodontal ligament fibroblasts' adhesion and may be one of important factors which participate in the periodontal regeneration.

[Heterotopic complex membrane induces bone formation].

OBJECTIVE: The composite membrane was made by recombinant human bone morphogenetic protein-2 (rhBMP-2), collagen (Co), polylactic-co-glycolic acid (PLGA). To observe the ectopic bone formation and evaluate the capability of rhBMP-2/Co/PLGA complex membrane. METHODS: 48 male Kunming adult mice were divided into two groups randomly: Co/PLGA complex membrane group and rhBMP-2/Co/PLGA complex membrane group. After etherized, an incision was made on the outer muscle and two groups of complex membranes were implanted into the right side hind limb muscle pouch. 8 mice from each group were sacrificed at 7, 14, 28 d. The hind limbs were removed, examined by soft X-ray, HE staining and light microscope examination. RESULTS: Wounds healed well, no infections and rejections were observed. In the Co/PLGA group, partial implanted membrane degradated and absorbed at 7 d. The membrane collagen fiber appeared loose at 14 d. The membrane lost its intact to disrupted at 28 d. No ectopic bone formation was found. In the rhBMP-2/Co/PLGA group, ectopic bone formation was found by eye, soft X-ray and histological examinations. The rhBMP-2/Co/PLGA complex membrane degraded slower than Co/PLGA complex membrane. CONCLUSION: Co/PLGA can provide a carrier for rhBMP-2 to have stronger effect of biological activity.

[Effect of basic fibroblast growth factor on the gene expression of epidermal growth factor receptor by periodontal ligament cells in culture].

OBJECTIVE: To study the effect of basic fibroblast growth factor (bFGF) on the gene expression of epidermal growth factor receptor (EGFR) by periodontal ligament cells (PDLC) in culture and discuss the effect of bFGF in cell differentiation and periodontal regeneration. METHODS: Human PDLC were cultured in vitro and cell clone was obtained by the method of limiting dilution. PDLC were stimulated by bFGF, and then gene expression of EGFR was assessed by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The mRNA expression of EGFR was promoted by bFGF and the effect was dose-dependent. CONCLUSION: The promotion effect of the mRNA expression of EGFR in PDLC may be one of important factors which participate in the healing process of periodontitis and provide partly theoretical basis of cell differentiation and periodontal regeneration.

[The effect of basic fibroblast growth factor on the gene expression of decorin by periodontal ligament fibroblasts in culture].

OBJECTIVE: To study the effect of basic fibroblast growth factor (bFGF) on the gene expression of decorin by periodontal ligament fibroblasts (PLFs) in culture, and discuss the effect of bFGF in periodontal regeneration. METHODS: Human PLFs were cultured and stimulated by exogenous bFGF. Gene expression of decorin was assessed by semi-quantitive RT-PCR. RESULTS: The mRNA expression of decorin was suppressed by bFGF and the effect was dose-dependent. When the dose of bFGF increased, the inhibitive effect decreased. CONCLUSION: Decorin has many biological effects. The inhibitive effect may be one of important factors which participate in the healing process of periodontitis, and provide partly theoretical basis of bFGF in periodontal regeneration.

[Papillon-Lefevre syndrome: a case report].

Papillon-Lefevre syndrome (PLS) is an extremely rare inherited disease as an autosomal recessive trait. The disorder is characterized by diffuse palmoplantar keratoderma and premature loss of both deciduous and permanent teeth. This paper described a case of PLS with classic clinical features and briefly reviewed the relevant literature.