Research progress on the role of mitochondrial dysfunction in the occurrence, progression and treatment of periodontitis / 口腔疾病防治

@#Periodontitis is a widespread disease worldwide, with the primary cause of tissue loss being an immune inflammatory response mediated by bacteria. Increasing evidence has revealed a significant correlation between mitochondrial dysfunction and the occurrence and progression of periodontitis. This paper provides a review of current research on the role of mitochondrial dysfunction in the occurrence and development of periodontitis and related therapies from the perspectives of oxidative stress, inflammatory responses, and the regulation of mitochondrial homeostasis. Mitochondria are the main source and target of cellular reactive oxygen species. Mitochondrial dysfunction can generate large amounts of reactive oxygen species, exacerbating local oxidative stress in periodontal tissues and causing cell toxicity and tissue damage. Mitochondria are also the center of cellular inflammatory responses, and the positive feedback loop of inflammation induced by mitochondrial dysfunction may explain the persistent and unresolved nature of periodontitis. Biomaterials loaded with pharmacological agents show potential in restoring mitochondrial function, controlling the development of periodontitis, and promoting periodontal tissue regeneration. However, the key sites of mitochondrial dysfunction in the occurrence and development of periodontitis are not yet fully understood, and the improvement of mitochondrial function in periodontal therapy is still in the experimental stage. Future research efforts should focus on the effect of mitochondrial dysfunction on periodontal cells and explore its specific mechanism in the occurrence and progression of periodontitis in order to provide new insights into the treatment of periodontitis.

Antibacterial copper sulfide/graphene oxide nanosheets composite film promotes angiogenic and osteogenic differentiation in vitro / 中华创伤骨科杂志

Objective:To investigate whether the antibacterial copper sulfide (CuS)/graphene oxide (GO) nanosheets composite film can promote angiogenesis and osteogenesis in vitro. Methods:GO and CuS/GO nanosheets were synthesized and mixed into polyvinyl alcohol (PVA)/carboxymethyl cellulose (CMC) hydrogel films. The study was conducted in 4 groups: PVA/CMC/GO, PVA/CMC/CuS/GO, PVA/CMC (only PVA/CMC-based film) and blank control (no material). The PVA/CMC, PVA/CMC/GO and PVA/CMC/CuS/GO films were characterized by electron scanning microscopy and energy dispersive spectrometer. The biocompatibility of different films (PVA/CMC/CuS/GO films with concentrations of CuS/GO nanotablets of 0, 50, 100, 200, 400, and 800 μ g/mL) was evaluated by CCK-8, live/dead cell staining, and hemolysis test. The angiogenesis was evaluated by cell migration and tube forming test in vitro. Alkaline phosphatase and alizarin red staining were used to evaluate osteogenesis in vitro, and the expression of osteogenic genes was measured by immunofluorescence staining and RT-qPCR. In addition, the bacterial plate counting method and bacteriostatic circle method were used to evaluate the antibacterial activity of films. Results:In the PVA/CMC/GO and PVA/CMC/CuS/GO groups, the surface of the PVA/CMC-based film was smooth and flat whereas the nanosheets composite films were irregularly flaky and convex. The biosafety experiments showed that the PVA/CMC-based film composited with GO or CuS/GO nanosheets at the concentration of 100 μg/mL had good biocompatibility. The results of angiogenesis in vitro showed that the migration ratio of HUVEC cells in the PVA/CMC/CuS/GO group was significantly better than those in the PVA/CMC/GO, PVA/CMC and control groups ( P<0.001). In the experiment of tube forming area and length, the PVA/CMC/CuS/GO group was significantly better than the PVA/CMC/GO, PVA/CMC and control groups ( P<0.001). The osteogenic differentiation in vitro displayed that the alkaline phosphatase and alizarin red staining of MC3T3-E1 cells in the PVA/CMC/CuS/GO group were significantly better than those in the PVA/CMC/GO, PVA/CMC and control groups ( P<0.001). In addition, the fluorescence intensity of immunofluorescence staining in alkaline phosphatase and type Ⅰcollagen on MC3T3-E1 cells, and the mRNA expression levels of osteogenic related genes including alkaline phosphatase, bone morphogenetic protein 2, osteocalcin and osteopontin in the PVA/CMC/CuS/GO group were significantly higher than those in the PVA/CMC/GO, PVA/CMC and control groups ( P<0.001). The antibacterial assay showed that the PVA/CMC/CuS/GO group had a significantly greater antibacterial activity and a significantly larger inhibition zone against Gram-positive bacteria and Gram-negative bacteria than the PVA/CMC/GO, PVA/CMC and control groups ( P< 0.001). Conclusions:PVA/CMC films composited with GO or CuS/GO nanosheets demonstrate ideal biocompatibility and antibacterial properties which promote angiogenesis and osteogenic differentiation in vitro. In particular, antibacterial PVA/CMC/CuS/GO composite films with the coupling function of angiogenesis and osteogenesis are expected to provide a new strategy for infectious bone defects.

Experimental Study on Puncture Mechanical Properties of Biomimetic Materials / 医用生物力学

Objective To obtain a more suitable puncture method for venipuncture robot through experiments.Methods By using different puncture speeds and angles for biomimetic materials, the force-time curves by various puncture methods were obtained. Results During puncture process, with the increase of the puncture angle, a smaller puncture force was required. The faster puncture speed would lead to a larger puncture force. Conclusions The 40°-45° puncture angleand the 120-300 mm/min puncture speed should be used for designing the puncture method of venipuncture robot. The results provide references for selecting the puncture angle and speed of the venipuncture robot.

Research progress in the application of polydopamine multifunctional nanocontrast agents in molecular imaging of tumors / 国际生物医学工程杂志

The development of multifunctional nanocontrast agents with high sensitivity, high specificity, and low toxicity so that they can precisely localize tumors and reflect tumor biological information in real time is the core of promoting the development of tumor molecular imaging technology and realizing early and precise tumor diagnosis. Polydopamine (PDA) nanomaterials are bionanomaterials with a structure extremely similar to that of natural melanin. They can be easily fabricated and functionalized, and can achieve controlled assembly of functional molecules such as contrast components and targeting ligands via metal coordination, π-π stacking, electrostatic adsorption, and other methods. They have good biocompatibility and biodegradability, show great potential for clinical translation, and have been widely used in molecular imaging of tumors. In this review paper, the preclinical studies of PDA nanoparticles are reviewed as well as the synthesis methods, functionalized modification, and assembly strategies of PDA nanoparticles and their applications in tumor molecular imaging. The development trends of PDA are also presented to promote their application in the field of tumor molecular imaging.

Effects of biomimetic network membrane prepared by chitosan/gelatin/pectin on proliferation and mineralization of mesenehymal stem cells / 吉林大学学报(医学版)

Objective::To explore the effects of the biomimetic network membrane prepared by chitosan/gelatin/pectin on the proliferation and mineralization of mesenchymal stem cells (MSCs) , and to evaluate its feasibility of constructing tissue engineering bone.Methods:Chitosan, gelatin and pectin were made into a new biomimetic network membrane in a certain ratio by biomimetics.The experiment was divided into control group (MSCs+conventional medium) , material group (MSCs+network membrane+conventional medium) and material+OS group (MSCs+network membrane+OS medium) .The cell morphology was observed by inverted phase contrast microscope;the growth and secretion of extracellular matrix of the MSCs were observed under scanning electron microscope (SEM) .The proliferation of cells was determined by MTT assay (The MSCs were divided into negative control group and material group, and they were cultivated with blank medium and medium including materials) .The expression of calcium in MSCs was detected by Alizarin Red staining.Real-time polymerase chain reaction (RT-PCR) was used to determine the expression levels of osteocalcin (OC) mRNA and osteopontin (OPN) mRNA in the MSCs.Results:The network membrane was semitransparent thin film.The MSCs were short shuttle and clustered under inverted phase contrast microscope.After cultured for 7d, the MSCs were shuttle;after cultured for 14d, the number of MSCs was increased, with pseudo feet on the membrane;after cultured for21d, the MSCs clustered with a lot of neo-formed extracellular matrix.The MTT results showed that there was no significant difference in the proliferation level of MSCs between material group and negative control group (P＞0.05) .The Alizarin Red staining results showed that the MSCs in the network membrane were dyed orange red.The RT-PCR results showed that the expression levels of OC mRNA in the MSCs in material group and material+OS group were lower on the 7th and 14th days, but on the 21th day, the expression levels were significantly increased and reached the peak;the expression level of OC mRNA in the MSCs in material group was significantly increased on the 7th day, and the expression level reached the peak on the 14th day, then fell slightly on the 21th day;compared with control group, the expression levels of OC mRNA and OPN mRNA in the cells in material group and material+OS group at different time points were significantly increased (P＜0.01) , but there were no significant differences between material group and material+OS group (P＞0.05) .Conclusion:Chitosan/gelatin/pectin biomimetic network membrane has good biocompatibility, and MSCs can grow and proliferate well on the membrane.The membrane can induce the MSCs to express mineralization-related genes and proteins without inducers.

Regulation of dentin remineralization progress by non-collagenous protein analogues / 中华口腔医学杂志

The use of various biomimetic methods to achieve remineralization of demineralized dentin and the formation of an organic matrix-inorganic mineral complex with a certain mechanical strength has been a research hotspot in recent years in the field of stomatology, and it also provides a new idea for the restoration of dentin defect. Dentin biomineralization is a process that simulates the mineralization of biological tissue in nature in which the remineralization of dentin collagen is induced and regulated by organic macromolecules. This review summarizes the process of remineralization of decalcified dentin regulated by non-collagenous protein analogues in vitro.

Efecto de agentes blanqueadores libres de peróxido sobre el color dental. Revisión sistemática / Effect of Peroxide-Free Dental Bleaching Agents on Dental Color. Systematic Review

Antecedentes: Los agentes blanqueadores oxidantes tales como los peróxidos generan daños irreversibles en el esmalte dental y afectan químicamente el componente orgánico e inorgánico del esmalte. Se reportan en la literatura sustancias alternativas que pueden mejorar el color del esmalte, sin causarle daño. Objetivo: Identificar las sustancias blanqueadoras tipo remineralizante reportadas en la literatura y su efecto en el color del esmalte dental. Métodos: Se consultaron las bases de datos PubMed, ScienceDirect, Embase, Scielo, Lilacs y Scopus, las palabras clave empleadas para la búsqueda fueron dental enamel, tooth bleaching, bleaching, calcium phosphate, hidroxyapatite, apatite, biomimetic, biomimetics, conectadas por el operador booleano AND y OR de diferentes maneras. Los criterios de elegibilidad de los artículos que harían parte de la revisión fueron que no incluyeran peróxidos de hidrógeno y carbamida con adición fluoruros y fosfatos de calcio y adicionalmente que emplearan un método de medición de color. Resultados: El resultado de la búsqueda arrojó 7 artículos, las sustancias encontradas de tipo remineralizante fueron hidroxiapatita sintética, fosfatos de calcio y el hexametafosfato de sodio. Según los criterios de evaluación definidos solo 4 de ellos tuvieron un nivel de evidencia alto, uno nivel medio y dos bajos. Todos los estudios reportan con los tratamientos probados, la capacidad de generar cambios en el color del esmalte dental. Conclusión: Las sustancias blanqueadoras remineralizantes encontradas, tienen la capacidad de producir cambios en el color del esmalte dental, lo cual se evidencia con modificación en las diferentes escalas de medición empleadas.

Background: Oxidizing bleaching agents such as peroxides generate irreversible damage to dental enamel and chemically affect the organic and inorganic component of the enamel. Alternative substances that can improve the color of the enamel without damaging it are reported in the literature. Purpose: To identify the remineralizing bleaching substances reported in the literature and their effect on the color of the dental enamel. Methods: The databases PubMed, ScienceDirect, Embase, SciELO, Lilacs and Scopus were consulted, the keywords used for the search were dental enamel, tooth bleaching, bleaching, calcium phosphate, hydroxyapatite, apatite, biomimetic, biomimetics, connected by the Boolean operator AND and OR in different ways. The eligibility criteria of the articles that would be part of the review were not to include hydrogen peroxide and carbamide peroxides with addition of fluorides and calcium phosphates and additionally using a color measurement method. Results: The result of the search yielded 7 articles, the substances found of remineralizing type were synthetic hydroxyapatite, calcium phosphates and sodium hexametaphosphate. According to the evaluation criteria defined, only 4 of them had a high level of evidence, one medium level and two low. All studies report with proven treatments the ability to generate changes in tooth enamel color. Conclusions: The remineralizing whitening substances found have the ability to produce changes in the color of the dental enamel, which is evidenced with modification in the different measurement scales used.

Effect of rewetting solutions on micropush-out dentin bond strength of new bioceramic endodontic material

Abstract To evaluate the influence of rewetting solutions on bond strength to root dentin of conventional gutta-percha (GP) or niobium phosphate glass-based gutta-percha (GNb) associated with a bioceramic sealer. The root canals of 80 human mandibular premolars were prepared using nickel-titanium instruments and irrigation with sodium hypochlorite and EDTA. The teeth were randomly divided into four groups according to the gutta-percha used: GNb or GP associated with EndoSequence BC Sealer (BC) and the solution for rewetting dentin before filling (distilled water; phosphate buffer saline solution - PBS; simulated body fluid - SBF; or no solution). The root canals were filled with a single cone using warm vertical condensation. Micropush-out bond strengths associated with the filling materials in slices from middle root thirds was determined 30 days after root filling. The failure mode was analyzed with stereoscopic lens. The data were statistically analyzed by two-way ANOVA and Holm-Sidak test (p < 0.05). There was significant difference in the types of gutta-percha (p < 0.001) and in the different rewetting solutions (p = 0.003). The interaction between gutta-percha and rewetting solutions was not significant (p = 0.53). The SBF solution provided an increase in bond strength for both gutta-percha solutions. The GNb+BC (3.42 MPa) association increased bond strength when compared with GP+BC (2.0 MPa). The use of SBF as a dentin rewetting solution increased bond strength in the groups studied. Association of GNb with bioceramic sealer was beneficial, increasing the bond strength to dentin when compared with the association with GP.

In vitro constructing artificial biomimetic periosteum / 中国组织工程研究

BACKGROUND:The smal intestinal submucosa has good biocompatibility and biodegradability, and also contains a variety of growth factors that can significantly promote celladhesion, proliferation and differentiation. Currently, the smal intestinal submucosa has been widely used in bone and cartilage, blood vessels, skin, bladder, smooth muscle and pancreatic tissue repair, showing good performance as a tissue-engineered cellscaffold. OBJECTIVE:To investigate the in vitro feasibility of tissue engineered periosteum constructed by porcine smal intestinal submucosa and osteoblasts differentiated from bone marrow mesenchymal stem cells. METHODS:Bone marrow mesenchymal stem cells were harvested from 2-week-old healthy New Zealand rabbits by using adherent method, and then cells were cultured, induced, differentiated and identified in vitro. Fol owing induced differentiation and identification, the bone marrow mesenchymal stem cells were compounded with porcine smal intestinal submucosa to fabricate tissue engineered periosteum. The adhesion, growth, and proliferation of cells on the materials were observed. RESULTS AND CONCLUSION:At 5 days after inoculation, the cells receiving osteogenic induction could quickly adhere and proliferate on the surface of porcine smal intestinal submucosa and be interconnected;at 10 days, the desmosomes formed among the cells, cellprocesses from osteoblasts were visible and attached to the smal intestine submucosa;at 15 days, cellproliferation and secretion of matrix appeared, and multi-layer membrane-like structure formed on the surface of the smal intestine submucosa. These findings indicate that after osteogenic induction, the bone marrow mesenchymal stem cells can be combined with porcine smal intestinal submucosa to construct a tissue engineered periosteum, which is hoped to be an ideal scaffold for tissue engineering.

Biopsy guided by ultrasound intellectual position technique: a phantom study / 中华超声影像学杂志

Objective To demonstrate the feasibility and accuracy of the intellectual position(IP)technique used in ultrasound-guided biopsy.Methods Several red spheres,which were 10 mm in diameter and visible in ultrasound,randomly placed in the tissue mimicking gel phantom.The biopsy was performed by two operators respectively.Each operator chose 25 spheres,each of which were performed biopsy guided by IP technique,free-hand ultrasound and ultrasound with guide bracket.The red dye in the biopsied sample meant successful performance.The time spend in per biopsy target,the success rate of biopsy and the length of the red dyed sample of the three methods were recorded,and comparison was made among them.Results The median time took in biopsy guided by IP technique was 95(rang,80-110)s,which was longer than that of free-hand ultrasound-guide[30 (rang,22-42) s,P ＜0.001] and ultrasound-guide with bracket [20(rang,15-28)s,P ＜0.001].The success rate of biopsy guided by IP technique was 98.0％ (49/50)which was as well as that guided by ultrasound-guide with bracket(96.0％,48/50,P =0.558),better than free-hand ultrasound-guide(78.0％,39/50,P =0.002).The median length of red dyed sample biopsied guided by IP technique was 8.0 (rang,7.0-8.5)mm,which was longer than that of free-hand ultrasoundguide[6.0(rang,4.0-8.0)mm,P =0.003] and ultrasound-guide with bracket[7.0(rang,6.0-8.0)mm,P =0.003].There was no statistically difference between the two operators in length of red dyed sample and success rate of biopsy guided by IP technique(P ＞0.05).Conclusions Biopsy guided by IP technique is a feasible and accuracy method,which will become an effectively supplement of the ultrasound-guide with bracket.

Biomimetics of crystal texture in dental enamel prism by self-assembly oligopeptide / 北京大学学报(医学版)

Objective: To evaluate the possibility of self-assembly oligopeptide(T2) for dental enamel biomimetics, especially for the prism’s crystal texture since it could prompt calcium phosphate precipitated in gel carrier. Methods:SEM (Scaning electron microscope) and TEM (Transmission electron microscope) were used to observe the morphologic presentation and ED(Electron diffraction) to crystal texture comparing with the human molar enamel powder. Results: (a) Flake-like and needle-like octacalcium phosphate precipitated in the gel carrier with self-assemble oligopeptide(T2). They transformed into rod-like hydroxyapatite crystals gradually in the following 2-4 weeks. (b) The rod-like hydroxyapatite may arrange or grow into bundles which are similar to the human enamel prisms in both appearance and size. (c) The rod-like hydroxyapatite showed polycrystal while the enamel prisms showed monocrystal under examination of ED. Conclusion:The self-assemble oligopeptide(T2) could regulate the speed of nucleation and crystallization of hydroxyapatite in morphology and crystalline size. Thus, the self-assembly oligopeptide and the gel carrier mineralization system could be primarily applied in biomimetic use for the crystallization of hydroxyaptite in dental prism in vitro.