Deficiency of interleukin-9 inhibits osteogenic potential in mice / 中国组织工程研究

BACKGROUND:Mouse osteogenic potential is regulated by the JAK-STAT signaling pathway,and interleukin-9 can regulate multiple cellular functions through the JAK-STAT pathway,which has the potential to be a novel cytokine that regulates osteogenic potential. OBJECTIVE:To investigate the effect of interleukin-9 deficiency on osteogenic potential in mice METHODS:The femurs collected from 2-month-old wild-type and interleukin-9 knockout mice were subjected to Micro-CT scanning to analyze the changes in bone mass.Then,hematoxylin-eosin staining,Masson staining,and immunohistochemical staining of type Ⅰ collagen were performed on the slices of the femurs of mice.Bone marrow cells from 2-month-old wild-type and interleukin-9 knockout mice were extracted for colony-forming assay and detection of osteogenic gene expression in bone marrow mesenchymal stem cells.To further verify whether interleukin-9 worked through the JAK-STAT pathway,the expression of STAT3 protein was detected by western blot. RESULTS AND CONCLUSION:Micro-CT results showed the bone mass of interleukin-9 knockout mice decreased significantly compared with that of wild-type mice.In addition,the bone mineral density,bone volume fraction,trabecular number significantly decreased and trabecular separation markedly escalated in interleukin-9 knockout mice.The findings of hematoxylin-eosin staining were consistent with Micro-CT results.Interleukin-9 knockout mice had lower bone trabecular density.Type I collagen immunohistochemistry staining and Masson staining indicated the number of type Ⅰ collagen positive osteoblasts was significantly reduced and the capacity of collagen formation was damaged in interleukin-9 knockout mice.The results of colony-forming assay indicated that the mineralization capacity of osteoblast in interleukin-9 knockout mice were significantly lower than that in wild-type mice.Western blot results showed that osteogenesis induction activated STAT3 signaling,and the pSTAT3 level in wild-type mice with osteogenic induction was significantly higher than that in interleukin-9 knockout mice with osteogenic induction.These findings suggest that interleukin-9 regulates osteogenesis through the JAK-STAT3 pathway and interleukin-9 deficiency inhibits osteoblast differentiation and function,which may lead to reduced bone mass in interleukin-9 knockout mice.

Effects of different polymers on biomimetic mineralization of small intestine submu-cosal scaffolds / 北京大学学报(医学版)

Objective:To explore the effects of different polymers on in vitro biomimetic mineralization of small intestinal submucosa(SIS)scaffolds,and to evaluate the physicochemical properties and bio-compatibility of the SIS scaffolds.Methods:The SIS scaffolds prepared by freeze-drying method were im-mersed in simulated body fluid(SBF),mineralized liquid containing polyacrylic acid(PAA)and mine-ralized liquid containing PAA and polyaspartic acid(PASP).After two weeks in the mineralized solu-tion,the liquid was changed every other day.SBF@SIS,PAA@SIS,PAA/PASP@SIS scaffolds were ob-tained.The SIS scaffolds were used as control group to evaluate their physicochemical properties and bio-compatibility.We observed the bulk morphology of the scaffolds in each group,analyzed the microscopic morphology by environment scanning electron microscopy and determined the porosity and pore size.We also analyzed the surface elements by energy dispersive X-ray spectroscopy(EDX),analyzed the struc-ture of functional groups by Flourier transformed infrared spectroscopy(FTIR),detected the water ab-sorption rate by using specific gravity method,and evaluated the compression strength by universal me-chanical testing machine.The pro-cell proliferation effect of each group of scaffolds were evaluated by CCK-8 cell proliferation method.Results:Under scanning electron microscopy,the scaffolds of each group showed a three-dimensional porous structure with suitable pore size and porosity,and crystal was observed in all the mineralized scaffolds of each group,in which the crystal deposition of PAA/PASP@SIS scaffolds was more regular.At the same time,the collagen fibers could be seen to thicken.EDX analysis showed that the characteristic peaks of Ca and P were found in the three groups of mineralized scaffolds,and the highest peaks were found in the PAA/PASP@SIS scaffolds.FTIR analysis proved that all the three groups of mineralized scaffolds were able to combine hydroxyapatite with SIS.All the scaf-folds had good hydrophilicity.The compressive strength of the mineralized scaffold in the three groups was higher than that in the control group,and the best compressive strength was found in PAA/PASP@SIS scaffold.The scaffolds of all the groups could effectively adsorb proteins,and PAA/PASP@SIS group had the best adsorption capacity.In the CCK-8 cell proliferation experiment,the PAA/PASP@SIS scaffold showed the best ability to promote cell proliferation with the largest number of living cells observed.Con-clusion:Compared with other mineralized scaffolds,PAA/PASP@SIS scaffolds prepared by mineralized solution containing both PAA and PASP have better physicochemical properties and biocompatibility and have potential applications in bone tissue engineering.

Research progress on dental materials for preventing root caries / 口腔疾病防治

@#The high incidence and untreated rate of root caries, a common and frequently occurring oral disease with challenging treatment in elderly individuals, is the main cause of tooth loss among elderly people, as rapid development results in pulpitis and periapical periodontitis or residual crown and root, which has been regarded as one of the common chronic oral diseases seriously affecting the quality of life of elderly people. Thus, early intervention and prevention are important. Traditional dental materials for preventing root caries have been widely used in clinical practice; however, they have the disadvantages of tooth coloring, remineralization and low sterilization efficiency. A series of new dental materials for preventing root caries have gradually become a research hotspot recently, which have the advantages of promoting the mineralization of deep dental tissue, prolonging the action time and enhancing adhesion. Future caries prevention materials should be designed according to the characteristics of root surface caries and the application population and should be developed toward simplicity, high efficiency and low toxicity. This review describes current research regarding anti-caries prevention material application, serving as a theoretical underpinning for the research of root caries prevention materials, which is important for both promotion in the effective prevention of root caries and improvement in the status of oral health and the quality of life among old people.

The effect of injectable platelet-rich fibrin and platelet-rich fibrin in regenerative endodontics: a comparative in vitro study

Abstract Objective To explore the feasibility of injectable platelet-rich fibrin (i-PRF) in regenerative endodontics by comparing the effect of i-PRF and platelet-rich fibrin (PRF) on the biological behavior and angiogenesis of human stem cells from the apical papilla (SCAPs). Methodology i-PRF and PRF were obtained from venous blood by two different centrifugation methods, followed by hematoxylin-eosin (HE) staining and scanning electron microscopy (SEM). Enzyme-linked immunosorbent assay (ELISA) was conducted to quantify the growth factors. SCAPs were cultured with different concentrations of i-PRF extract (i-PRFe) and PRF extract (PRFe), and the optimal concentrations were selected using the Cell Counting Kit-8 (CCK-8) assay. The cell proliferation and migration potentials of SCAPs were then observed using the CCK-8 and Transwell assays. Mineralization ability was detected by alizarin red staining (ARS), and angiogenesis ability was detected by tube formation assay. Real-time quantitative polymerase chain reaction (RT-qPCR) was performed to evaluate the expression of genes related to mineralization and angiogenesis. The data were subjected to statistical analysis. Results i-PRF and PRF showed a similar three-dimensional fibrin structure, while i-PRF released a higher concentration of growth factors than PRF ( P <.05). 1/4× i-PRFe and 1/4× PRFe were selected as the optimal concentrations. The cell proliferation rate of the i-PRFe group was higher than that of the PRFe group ( P <.05), while no statistical difference was observed between them in terms of cell mitigation ( P >.05). More importantly, our results showed that i-PRFe had a stronger effect on SCAPs than PRFe in facilitating mineralization and angiogenesis, with the consistent result of RT-qPCR ( P <.05). Conclusion This study revealed that i-PRF released a higher concentration of growth factors and was superior to PRF in promoting proliferation, mineralization and angiogenesis of SCAPs, which indicates that i-PRF could be a promising biological scaffold for application in pulp regeneration.

Improvement of osteoblast adhesion, viability, and mineralization by restoring the cell cytoskeleton after bisphosphonate discontinuation in vitro

Abstract Bisphosphonates are prescribed to treat excessive bone resorption in patients with osteoporosis. However, its use is associated with potential adverse effects such as medication-related osteonecrosis of the jaw, prompting the introduction of the drug holiday concept in patients prior to dentoalveolar surgery. Furthermore, bisphosphonate discontinuation has been studied in vivo, in humans, and in animal models. However, it is not known whether this approach could affect bone cells in vitro. Therefore, the objective of this study was to investigate the potential effects of bisphosphonate discontinuation on pre-osteoblast and osteoblast activities in vitro. Methodology Pre-osteoblasts (MC3T3) and osteoblasts were treated with bisphosphonate (alendronate) at concentrations of 1, 5, and 10 µM. Alendronate was then withdrawn at different time points. The negative control consisted of untreated cells (0 µM), while the positive control consisted of cells incubated with alendronate throughout the experiment. Cell viability, cell adhesion, cell cytoskeleton, mineralization, and gene expressions were investigated. Results Pre-osteoblasts and osteoblasts showed a decrease in cell viability after treatment with 5-10 μM alendronate for 4 days or longer. Two days of alendronate discontinuation significantly increased cell viability compared with the positive control. However, these levels did not reach those of the negative control. Bone nodule formation was reduced by alendronate. Discontinuation of alendronate regained bone nodule formation. Longer periods of discontinuation were more effective in restoring nodule formation than shorter periods. Addition of alendronate resulted in an increase in the percentage of dead cells, which, in turn, decreased when alendronate was discontinued. Alendronate affected the cell cytoskeleton by disassembling actin stress fibers. Cell adhesion and cell morphological parameters were also affected by alendronate. Discontinuation of alendronate restored cell adhesion and these parameters. Overall, the highest improvement after alendronate discontinuation was seen at 10 µM. However, alendronate treatment and discontinuation did not affect osteoblast gene expression. Conclusion Discontinuation of alendronate helps to reverse the negative effects of the drug on cell viability, cell adhesion, and mineralization by restoring the cell cytoskeleton. Our data suggest the benefits of drug holiday and/or intermittent strategies for alendronate administration at the cellular level.

Age estimation through the development of third molars in a case of multiple dismemberment / Estimación de la edad mediante el desarrollo de terceros molares en un caso de desmembramiento múltiple

El crimen organizado se ha convertido en un flagelo a nivel internacional conformado por grupos al margen de la ley que realizan todo tipo de actividades que involucran desde tráfico de personas, secuestros, extorsiones, narcotráfico y muchos otros delitos. Producto de este fenómeno, la desaparición y ejecución de personas es cada día más frecuente, en muchos casos los cuerpos son quemados o desmembrados para impedir o hacer más difícil la identificación. La odontología forense se ha convertido en una disciplina transcendental en la identificación de cadáveres y restos óseos, además de contar con múltiples métodos para estimar la edad aproximada de una persona. Se presenta el caso de un descuartizamiento múltiple de tres individuos masculinos donde era indispensable identificar si alguno correspondía a una persona menor de 18 años.

Organized crime has become an international scourge made up of outlaw groups that carry out all kinds of activities ranging from human trafficking, kidnapping, extortion, drug trafficking and many more. As a result of this phenomenon, the disappearance and execution of people is becoming more frequent every day, in many cases the bodies are burned or dismembered to prevent or make identification more difficult. Forensic odontology has become a transcendental discipline in the identification of corpses and skeletal remains, in addition to having multiple methods to estimate the approximate age of a person. The case of a multiple dismemberment of three male individuals is presented, where it was essential to identify a person under 18 years of age.

Low concentrations of grape seed extract maintain osteoblast morphology, cell adhesion, and mineralization

Abstract The increase in life expectancy has led to a higher incidence of osteoporosis, characterized by an imbalance in bone remodeling. Several drugs are used for its treatment, but most promote undesirable side effects. The present investigation evaluated the effects of two low concentrations of grape seed extract (GSE) rich in proanthocyanidins on MC3T3-E1 osteoblastic cells. The cells were cultured in an osteogenic medium and divided into control (C), 0.1 µg/mL GSE (GSE0.1), and 1.0 µg/mL GSE (GSE1.0) groups to evaluate cell morphology, adhesion, and proliferation, in situ alkaline phosphatase (ALP) detection, mineralization and immunolocalization of osteopontin (OPN). The data obtained were analyzed by statistical tests for a significance of 5%. Cell morphology was maintained with both GSE concentrations, whereas cell adhesion significantly increased within three days in all groups. Cell proliferation increased significantly at seven days of culture, followed by a significant decrease in all experimental periods, with no statistical difference among them. In situ detection of ALP and mineralization increased with time, but within each period, no statistical differences among groups were observed. The expression of osteopontin was distributed regularly with more intensity after 24 hours in the GSE0.1 group. After three days, OPN expression was more intense in the control group, followed by GSE0.1 and GSE1.0 groups. Data obtained suggest that low concentrations of GSE do not affect the morphology and may stimulate the functional activity of osteoblastic cells.

Resumo O aumento da expectativa de vida tem levado a uma maior incidência de osteoporose, caracterizada por um desequilíbrio na remodelação óssea. Vários medicamentos são utilizados para o seu tratamento, contudo, a maioria promove efeitos colaterais indesejáveis. A presente investigação avaliou os efeitos de duas baixas concentrações de extrato de semente de uva (GSE) rico em proantocianidinas em células osteoblásticas MC3T3-E1. As células foram cultivadas em meio osteogênico e divididas em grupos controle (C), 0,1 µg/mL de GSE (GSE0.1) e 1,0 µg/mL de GSE (GSE1.0) para avaliar morfologia, adesão e proliferação celular, detecção in situ de fosfatase alcalina (ALP), mineralização e imunolocalização da proteína osteopontina (OPN). Os dados obtidos foram analisados por testes estatísticos para um nível de significância de 5%. A proliferação celular aumentou significativamente aos sete dias de cultura, seguido de uma diminuição significativa em todos os períodos experimentais, sem diferença estatística entre eles. A detecção in situ de ALP e mineralização aumentou com o tempo, mas dentro de cada período não foram observadas diferenças estatísticas entre os grupos. A morfologia celular foi mantida com ambas as concentrações de GSE, enquanto a adesão celular aumentou significativamente aos três dias em todos os grupos. A expressão de osteopontina distribuiu-se regularmente com maior intensidade após 24 horas no grupo GSE0.1. Após três dias, a expressão de OPN foi mais intensa no grupo controle, seguida pelos grupos GSE0.1 e GSE1.0. Os dados obtidos sugerem que baixas concentrações de GSE não afetam a morfologia e podem estimular a atividade funcional das células osteoblásticas.

Effect of the chicken zp1 gene on osteoblast mineralization / 生物工程学报

The aim of this study was to clone the chicken zp1 gene encoding zona pellucida 1 (Zp1) and investigate its tissues expression profile and its effect on osteoblast mineralization. The expression level of zp1 was quantified in various tissues of laying hens and in the tibia of the pre- and post-sexual maturity by RT-qPCR. Zp1 overexpressed vector was transfected into chicken calvarial osteoblasts which were induced differentiation for 8 days, and the extracellular mineral and the expression of mineralization-related genes were detected. The full-length chicken zp1 gene is 3 045 bp, encoding 958 amino acids residuals, and has two N-glycosylation sites. The highest expression level of the zp1 gene was found in the liver, followed by the tibia and yolk membrane, while no expression was detected in the heart and eggshell gland. Compared with the pre-sexual maturity hens, the concentration of estrogen (E2) in plasma, the content of glycosaminoglycan (GAG) and the expression level of the zp1 gene in the tibia with post-sexual maturity were higher. The extracellular matrix and the level of osteoblast mineralization-related genes showed a significantly upregulated expression in chicken calvarial osteoblasts with Zp1 overexpressed and addition of estrogen. The expression of the zp1 gene is tissue-specific and positively regulated osteoblast mineralization under the action of estrogen, laying the foundation for elucidating the functional properties of Zp1 in chicken bones during the egg production period.

Er，Cr : YSGG laser accelerated dentin mineralization / 安徽医科大学学报

Objective @#To study the effect of Er，Cr : YSGG laser on the mineralization of dentin collagen fiber，accelerate the mineralization process and shorten the mineralization time．@*Methods@#Human health third molarswere selected to remove the teeth of the tooth enamel，degenerate the teeth，leave the dentin collagen fiber web，place the degenerative collagen fiber in the configured re-mineral fluid．Using Er，Cr : YSGG，the teeth before and after the test were used to analyze the surface morphology using SEM scanning electron microscopy，and the EDS X-ray energy spectrum was analyzed by the distribution of calcium phosphorus. @*Results@# Er，Cr : YSGG laser irradiation laser irradiated tooth in the teeth in the teeth，new minerals were generated，which covered the inner wall of the teeth，the calcium phosphorus element was enriched in the inner wall of the teeth．@*Conclusion @#YSGG laser can help dentin collagen fibers mineralized in mineralization fluid，form new minerals．This method can shorten the mineralization time of dentin collagen fibers in mineralization fluid，which is the re-ore.

Mechanism of microRNA-30d-5p regulating osteogenic differentiation of bone marrow stromal cells through glucose-regulated 78 / 解剖学报

Objective To investigate the effect of microRNA(miR)-30d-5p on osteogenic differentiation and apoptosis of bone marrow stromal cells and its mechanism. Methods Bone marrow stromal cells were divided into miR-30d-5p overexpression negative control group, miR-30d-5p overexpression group, miR-30d-5p inhibition negative control group and miR-30d-5p inhibition group. Alkaline phosphatase (ALP) staining was used to identify osteogenesis, alizarin red staining was used to detect calcium nodules precipitation, and TUNEL was used to detect apoptosis. mRNA and protein expression levels were detected by Real-time PCR and Western blotting, and the potential binding sites of miR-30d-5p were predicted by the bioinformatics analysis website Targetscan 7.1. Results After miR-30d-5p overexpression, osteogenic differentiation ability, and mineralization ability of the cells decreased (P<0.05), while apoptosis level increased (P< 0.05). The expression of glucoregulatory protein 78 (GRP78) and osteogenic specific transcription factor Runt related transcription factor 2(RUNX2) decreased significantly (P<0.05). However, miR-30d-5p inhibitor-treated the cells with increased osteogenic differentiation and mineralization ability (P < 0.05), and apoptosis level decreased (P < 0.05). GRP78 and RUNX2 protein levels increased (P<0.05). The miR-30d-5p binding site was located at 142-148 bp of the 3'UTR of the GRP78 gene. Conclusion MiR-30d-5p inhibits osteogenic differentiation and promotes apoptosis of bone marrow stromal cells by down-regulating the expression of GRP78 protein.

Converting bacteria into autologous tumor vaccine via surface biomineralization of calcium carbonate for enhanced immunotherapy

Autologous cancer vaccine that stimulates tumor-specific immune responses for personalized immunotherapy holds great potential for tumor therapy. However, its efficacy is still suboptimal due to the immunosuppressive tumor microenvironment (ITM). Here, we report a new type of bacteria-based autologous cancer vaccine by employing calcium carbonate (CaCO3) biomineralized Salmonella (Sal) as an in-situ cancer vaccine producer and systematical ITM regulator. CaCO3 can be facilely coated on the Sal surface with calcium ionophore A23187 co-loading, and such biomineralization did not affect the bioactivities of the bacteria. Upon intratumoral accumulation, the CaCO3 shell was decomposed at an acidic microenvironment to attenuate tumor acidity, accompanied by the release of Sal and Ca2+/A23187. Specifically, Sal served as a cancer vaccine producer by inducing cancer cells' immunogenic cell death (ICD) and promoting the gap junction formation between tumor cells and dendritic cells (DCs) to promote antigen presentation. Ca2+, on the other hand, was internalized into various types of immune cells with the aid of A23187 and synergized with Sal to systematically regulate the immune system, including DCs maturation, macrophages polarization, and T cells activation. As a result, such bio-vaccine achieved remarkable efficacy against both primary and metastatic tumors by eliciting potent anti-tumor immunity with full biocompatibility. This work demonstrated the potential of bioengineered bacteria as bio-active vaccines for enhanced tumor immunotherapy.

Dose-dependent effects of neem crude extract on human dental pulp cell and murine osteoblast viability and mineralization

Abstract Neem has been used as a medicine due to its beneficial properties such as anti-microbial effects. Neem products for oral application are on the rise. Before recommendation for therapeutic use in human, its effects on cellular activities need to be examined. Therefore, the aim of this study was to test the effects of the ethanolic neem crude extract on dental pulp cells and osteoblasts in terms of cell viability, mineralization, and gene expressions. The ethanolic neem extract derived from dry neem leaves was subjected to chemical identification using GC-MS. Human dental pulp stem cells (hDPSCs) and pre-osteoblasts (MC3T3) were treated with various concentrations of the neem crude extract. Cell viability, mineralization, and gene expressions were investigated by MTT assay, real-time PCR, and alizarin red S assay, respectively. Statistical analysis was performed by one-way ANOVA followed by Dunnett test. GC-MS detected several substance groups such as sesquiterpene. Low to moderate doses of the neem crude extract (4 - 16 µg/ml) did not affect hDPSC and MC3T3 viability, while 62.5 µg/ml of the neem extract decreased MC3T3 viability. High doses of the neem crude extract (250 - 1,000 µg/ml) significantly reduced viability of both cells. The neem crude extract at 1,000 µg/ml also decreased viability of differentiated hDPSC and MC3T3 and their mineralization. Furthermore, 4 µg/ml of neem inhibited viability of differentiated hDPSC. There is no statistical difference in gene expressions related to cell differentiation. In conclusion, the neem crude extract affected cell viability and mineralization. Cell viability altered differently depending on the doses, cell types, and cell stages. The neem crude extract did not affect cell differentiation. Screening of its effect in various aspects should be examined before the application for human use.

Resumo O Neem tem sido utilizado como medicamento devido às suas propriedades benéficas, tais como os efeitos antimicrobianos. Os produtos Neem para aplicação oral estão a aumentar. Antes da recomendação para uso terapêutico no ser humano, os seus efeitos nas atividades celulares precisam ser examinados. Por conseguinte, o objectivo deste estudo era testar os efeitos do extracto bruto de neem etanólico nas células de polpa dentária e osteoblastos em termos de viabilidade celular, mineralização e expressões genéticas. O extracto de neem etanólico derivado de folhas secas de neem foi sujeito a identificação química utilizando GC-MS. As células estaminais de polpa dentária humana (hDPSCs) e os pré-osteoblastos (MC3T3) foram tratados com várias concentrações do extrato bruto de neem. A viabilidade celular, mineralização, e expressões genéticas foram investigadas pelo ensaio MTT, PCR em tempo real, e o ensaio S vermelho de alizarina, respectivamente. A análise estatística foi realizada por ANOVA unidirecional seguida pelo teste Dunnett. O GC-MS detectou vários grupos de substâncias como o esquisterpeno. Doses baixas a moderadas do extracto bruto de neem (4 - 16 µg/ml) não afetaram a viabilidade do hDPSC e MC3T3, enquanto 62,5 µg/ml do extracto de neem diminuiu a viabilidade do MC3T3. Doses elevadas do extrato bruto de neem (250 - 1.000 µg/ml) reduziram significativamente a viabilidade de ambas as células. O extrato bruto de neem a 1.000 µg/ml também diminuiu a viabilidade de hDPSC e MC3T3 diferenciados e a sua mineralização. Além disso, 4 µg/ml de neem inibiu a viabilidade do hDPSC diferenciado. Não há diferença estatística nas expressões genéticas relacionadas com a diferenciação celular. Em conclusão, o extrato bruto do neem afetou a viabilidade celular e a mineralização. A viabilidade celular alterou-se diferentemente dependendo das doses, tipos de células, e fases celulares. O extrato bruto do neem não afetou a diferenciação celular. O rastreio do seu efeito em vários aspectos deve ser examinado antes da aplicação para uso humano.

The pivotal role of autophagy in bone cells:bone-related cell activity and bone metabolism / 中国组织工程研究

BACKGROUND:The importance of autophagy for maintaining cellular homeostasis and stress response has long been recognized.As a way for cells to selectively clear their damaged organelles to achieve the recycling of cellular components,autophagy has a pivotal role in bone metabolism.OBJECTIVE:To review the role and possible mechanisms of autophagy in regulating bone-related cell activity and function among bone marrow mesenchymal stem cells,osteoblasts,osteocytes,and osteoclasts.METHODS:PubMed was searched for studies related to autophagy using the keywords of "autophagy;bone marrow mesenchymal stem cells;osteoblasts;osteocytes;osteoclasts."RESULTS AND CONCLUSION:We finally included 84 papers.Autophagy plays an important role in bone metabolism.Autophagy is involved in maintaining the balance between mineralization and absorption,and then maintaining bone homeostasis.An appropriate autophagy inducer may also benefit bone remodeling.Abnormal autophagy can lead to disorders of bone balance,leading to diseases such as osteoporosis.We may prevent or treat bone-related diseases by regulating the level of autophagy as its function in maintaining the balance of mineralization and resorption in bone homeostasis.

Study on the inhibition and remineralization of enamel demineralization by polydopamine in vitro / 口腔疾病防治

Objective@#To investigate the inhibitory effect of polydopamine (PDA) on enamel demineralization in isolated teeth and the induction of hydroxyapatite (HA) production on the surface of demineralized enamel to provide a novel protocol for the prevention and treatment of enamel demineralization. @*Methods@#Twenty isolated bovine teeth were cut into 20 enamel slices and randomly divided into an experimental group and a control group, with 10 slices in each group. The enamel slices in the experimental group were immersed in 2 mg/mL freshly prepared dopamine solution and incubated for 24 hours at room temperature in the dark to prepare the PDA coating, while the control group was left untreated. Then, the isolated bovine teeth, with and without PDA coating, were immersed in artificial demineralization solution at 37 °C for 3 days, followed by 7 days in simulated body fluid (SBF), and the immersion solution was changed daily. The surface morphology of enamel was observed by scanning electron microscopy (SEM), the calcium/phosphorus ratio of the enamel surface was analyzed by energy dispersive spectroscopy (EDS), and the characteristic functional groups in enamel deposits were analyzed by Fourier transform infrared spectroscopy (FTIR).@* Results@#Compared with the control group, the number of demineralized pores produced after 3 d of enamel demineralization with polydopamine coating was less, and the diameter was smaller. EDS elemental analysis showed that the Ca/P ratio after enamel demineralization was 2.37 in the experimental group, which was smaller than the 2.53 ratio in the control group. In the remineralization experiment, after 7 days of remineralization of PDA coated enamel in the experimental group, lamellar grains were produced on the enamel surface, and the growth showed obvious directionality, growth regularity and uniform arrangement. In the control group, the surface of enamel was flocculent mineral deposit, and the crystallinity was poor. The FTIR results proved that the enamel surface deposit of PDA-coated enamel was HA after 7 d of remineralization. @*Conclusion @#PDA can affect the nucleation process of HA and promote the production of HA on the surface of demineralized enamel.

Biomechanical Environment Regulates Biomimetic Mineralization of Bone Matrix / 医用生物力学

Bone defects have always been an important cause of threat to human health, and artificial biomimetic bone repair replacement materials are currently one of the most effective and feasible solution approaches to treat bone damage. To develop artificial bone biomimetic materials, an in vitro biomimetic mineralization system must be constructed first to study in vitro biomimetic mineralization mechanism of natural bone matrix. Collagen is a template for mineralization, and its properties such as crosslinking degree, diameter, osmotic pressure, and surface charge can all directly affect mineralization progress. The biochemical and mechanical environments in which mineralization occurs are also quite distinct in their effects on mineralization process, particularly noncollagenous proteins and fluid shear stress (FSS). FSS is considered to be the main mechanical stimulation of bone tissues in micro-environment, which is of great significance to bone growth, repair and health maintenance. FSS at different levels and loading regimes has significant effects on transformation of amorphous calcium phosphate to bone apatite, self-assembly and directional alignment of collagen fibrils, and formation of hierarchical intrafibrillar mineralization. In this paper, the factors affecting collagen mineralization and their mechanism were summarized, with focus on regulation of FSS on collagen mineralization, and development direction in future was also prospected.

Particle size of oyster shell meal and calcium: phosphorus ratios in broiler diets / Efeito do tamanho de partícula da farinha de ostras e relações cálcio: fósforo em dietas para frangos de corte

The effects of Ca:P total ratio and particle size of oyster shell meal (OSM) were evaluated in broiler diets. In Experiment 1, 800 broilers (22-42 days old) were distributed in a 2×2 factorial design, with two Ca:P ratios (1.7 and 2.0:1) and two OSM particle sizes (coarse = 1,354 µm and fine = 428 µm), totaling four treatments with 10 repetitions with 20 broilers. Feed intake, weight gain, and feed conversion ratio were calculated. In Experiment 2, 1,280 broilers were distributed in a 2×2×2 factorial design (1.7 and 2.0:1 Ca:P ratios; coarse and fine OSM; male and female broilers), with eight treatments and 16 repetitions with 10 broilers. Apparent metabolizability of dry matter, Ca, P, and apparent metabolizable energy (AME), as well as bone resistance, bone weight, ash, Ca, and P content in the tibia were assessed. Growth performance was not affected (P > 0.05). Coarse OSM increased tibia Ca content in male broilers (P < 0.001), and higher Ca:P ratio improved bone ash and bone resistance in both sexes (P < 0.001), but reduced P content in male broilers (P < 0.05); male broilers displayed heavier bones with higher ash content than females (P < 0.05). Metabolizability of Ca was improved with coarse OSM (P < 0.05); whereas metabolizability of DM, P, and AME was not affected (P > 0.05). In conclusion, diets with a Ca:P total ratio of 2.0:1 containing coarser OSM improved bone mineral composition, particularly in male broilers, and coarse OSM improved the metabolizability of Ca in broilers regardless of the Ca:P total ratio or broiler sex.

Dois experimentos foram conduzidos para avaliar os efeitos do tamanho de partícula da farinha de ostras (FO) e relação Ca:P total em dietas para frangos de corte. No primeiro experimento, 800 frangos (22 a 42 dias) foram distribuídos em um delineamento fatorial 2x2: 2 relações Ca:P (1,7 e 2,0:1) e dois tamanhos de partícula da FO (grossa = 1354 µm e fina = 428 µm), totalizando quatro tratamentos com 10 repetições de 20 aves. O consumo de ração, o ganho de peso e a conversão alimentar foram calculados. No segundo experimento, 1.280 frangos foram distribuídos em um fatorial 2x2x2 (relações Ca:P 1,7 e 2,0:1; FO grossa e fina; aves machos e fêmeas) com oito tratamentos e 16 repetições de 10 aves. Foram avaliados: metabolizabilidade aparente da matéria seca, Ca e P, energia metabolizável aparente (EMA), peso e resistência óssea, conteúdo de cinzas, Ca e P na tíbia. As variáveis de desempenho não foram afetadas (P > 0,05). O uso de FO grossa aumentou o conteúdo de Ca na tíbia de frangos machos (P < 0,001), e a relação Ca:P de 2,0:1 aumentou o conteúdo de cinzas e aprimorou resistência óssea em ambos os sexos (P < 0,001), porém reduziu P na tíbia dos machos (P < 0,05); frangos machos também tiveram ossos mais pesados e maior conteúdo de cinzas do que fêmeas (P < 0,05). A metabolizabilidade de Ca foi melhorada com FO grossa, enquanto a metabolizabilidade da matéria seca, P, e EMA não foram afetadas (P > 0,05). Conclui-se que as dietas com relação Ca:P de 2,0:1 e com FO grossa resultaram em melhor composição mineral óssea - particularmente em frangos machos - e a FO grossa melhorou a metabolizabilidade de Ca independentemente da relação Ca:P ou do gênero das aves.

Ação antimicrobiana e antibiofilme de flavonóis isolados ou incorporados em hidrogéis termossensíveis e sua influência sobre marcadores de mineralização em células odontoblastóides para aplicação em endodontia / Antimicrobial/antibiofilm action of flavonols alone or incorporated in thermosensitive hydrogels and their influence on mineralization markers in odontoblast-like cells for endodontic applications

Ainda não foi encontrado um medicamento capaz de desinfetar os canais radiculares e permitir a recuperação celular e a regeneração tecidual em dentes permanentes jovens com comprometimento endodôntico. Dois importantes flavonóis detectados no vinho tinto, morina (MO) e miricetina (MY), são atualmente estudados por suas amplas propriedades biológicas, incluindo atividade antimicrobiana. No entanto, o desenvolvimento de sistemas de liberação controlada pode ser útil para a liberação desses flavonóis para fins de terapia endodôntica. Este estudo avaliou a citocompatibilidade e os efeitos antimicrobianos/antibiofilme de MO e MY, isolados ou incorporados em hidrogéis termorreversíveis de quitosana-poloxamer-ß-glicerofosfato de sódio (CPG), além dos efeitos de MO e MY, isolados e combinados sobre a viabilidade, atividade de ALP e produção de nódulos de mineralização em células MDPC-23. A atividade antimicrobiana dos compostos foi avaliada em Streptococcus mutans, Enterococcus faecalis, Actinomyces israelii e Fusobacterium nucleatum em condições planctônicas, em biofilmes dual-espécies e multiespécies e analisadas por contagem bacteriana e microscopia de varredura. Os hidrogéis CPG foram caracterizados por reometria de fluxo e oscilatória, temperatura de gelificação, perfil de textura e análise de bioadesão em espécimes de dentina. MO, MY e controles (hidróxido de cálcio ­ CH e clorexidina ­ CHX) foram incorporados em hidrogéis de CPG e o efeito do antibiofilme sobre biofilmes multiespécies formados em amostras de dentina radicular foi avaliado por microscopia confocal. O efeito de toxicidade dos compostos isolados ou incorporados em hidrogéis de CGP foi determinado em cultura de fibroblastos por ensaios de resazurina. Os dados foram analisados estatisticamente pelos testes ANOVA e Tukey considerando p < 0,05. A combinação de MO e MY foi sinérgica ou aditiva contra bactérias endodônticas testadas a partir de concentrações de 0,03 mg/mL MO + 0,06 mg/mL MY e não foram tóxicas para fibroblastos até 0,125mg/mL. MO + MY apresentou melhor efeito sobre biofilmes dual-espécies e multiespécies considerando suas menores concentrações quando comparados com os flavonóis isolados. Os hidrogéis CPG foram caracterizados como termorreversíveis e com propriedades mecânicas e bioadesivas adequadas. Hidrogéis de CPG carregados com MO+MY, CH e CHX apresentaram efeitos inibitórios semelhantes quando aplicados em biofilmes multiespécies formados no interior dos túbulos dentinários radiculares por 48h e seus extratos apresentaram citotoxicidade acima de 50% de diluição. As células semelhantes a odontoblastos (MDPC-23) foram expostas a diferentes concentrações de MO, MY, isoladamente ou em combinação e CH como controle positivo por 24h e 48h, e troca contínua de meio osteogênico por 8 dias e 14 dias. As combinações de MO+MY ou CH também foram incorporadas em hidrogéis de quitosana-poloxamer-ß-glicerofosfato e seus extratos em meio de cultura celular foram coletados após 48h e 7 dias. Viabilidade celular, atividade de fosfatase alcalina (ALP) e ensaios de deposição de nódulos mineralizados (MN) foram realizados pelo método de resazurina, ensaios de monofosfato de timolftaleína e coloração com vermelho de alizarina, respectivamente. Todos os compostos não causaram citotoxicidade nas concentrações testadas em 24h e 8 dias e 0,5 mg/mL MO e MY isolados reduziram a viabilidade celular em 48h. A atividade de ALP e a deposição de MN foram aumentadas para a combinação MO+MY e CH em células MDPC-23. Extratos de hidrogel de 7 dias contendo ou não MO+MY não foram citotóxicos até diluição de 25% em 48h e em baixas concentrações estimularam a atividade de ALP e deposição de MN aos 8 e 14 dias de avaliação. Em conclusão, a combinação de morina e miricetina incorporada ou não em hidrogéis de CPG apresentou efeito antibiofilme sobre patógenos orais e baixa toxicidade sobre fibroblastos. Morina e miricetina em baixas concentrações, isoladas, em combinação ou em hidrogéis CPG não foram citotóxicas e foram eficazes na indução de marcadores de mineralização em células semelhantes a odontoblastos(AU)

A drug capable of disinfecting the root canals and allow cell recovery and tissue regeneration in permanent young teeth with endodontic problems has not been found yet. Two important flavonols detected in red wine, morin (MO) and myricetin (MY), are currently studied for their wide biological properties including antimicrobial activity. However, the development of controlled release systems could be useful for the delivery of these flavonols for endodontic therapies. This study evaluated the cytocompatibility and antimicrobial/antibiofilm effects of MO and MY, alone or incorporated in thermoreversible chitosanpoloxamer hydrogels containing sodium ß-glycerophosphate (CPG), in addition to the effects of isolated and combined morin and myricetin flavonols on viability, ALP activity and production of mineralization nodules in MDPC-23 cells. Antimicrobial activity of the compounds was evaluated on Streptococcus mutans, Enterococcus faecalis, Actinomyces israelii, and Fusobacterium nucleatum under planktonic conditions, on dual-species and multispecies biofilms and analyzed by bacterial counts and scanning microscopy. CPG hydrogels were characterized by flow and oscillatory rheometry, gelation temperature, texture profile and bioadhesion analysis in dentin specimens. MO, MY and controls (calcium hydroxide ­ CH and chlorhexidine ­ CHX) were incorporated in CPG hydrogels and antibiofilm effect on multispecies biofilms formed in radicular dentin samples were evaluated by confocal microscopy. Cytotoxicity of the compounds alone or incorporated in CGP hydrogels was determined on fibroblasts culture by resazurin assays. Data were statistically analyzed by ANOVA and Tukey considering p < 0.05. The combination of MO and MY had synergistic or additive against oral bacteria tested starting at concentrations of 0.03 mg/mL MO + 0.06 mg/mL MY and they were not toxic to fibroblasts up to 0.125mg/mL. MO + MY had better effect on dual-species and multispecies biofilms considering their lower concentrations when compared with the flavonols alone. CPG hydrogels were characterized as thermoreversible and with adequate mechanical and bioadhesive properties. CPG hydrogels loaded with MO+MY, CH and CHX have similar inhibitory effects when applied on multispecies biofilms formed inside root dentin tubules for 48h and their extracts were cytotoxicity above 50% dilution. Furthermore, the effects of morin, myricetin, alone or in combination or incorporated in chitosan-based hydrogels on cytotoxicity and expression of mineralization markers in odontoblast-like cells. The MDPC-23 cells were exposed to different concentrations of morin (MO), myricetin (MY), alone or in combination and calcium hydroxide (CH) as a positive control for 24h and 48h, and continuous osteogenic medium changing for 8 days and 14 days. The combinations of MO+MY or CH were also incorporated in chitosan-poloxamer-ß- glycerophosphate hydrogels and their extracts in cell culture media were collected after 48h and 7 days. Cell viability, alkaline phosphatase (ALP) activity and assays mineralized nodules (MN) deposition were performed using resazurin method, thymolphthalein monophosphate assays and alizarin red staining, respectively. Data were statistically analyzed considering p< 0.05. All compounds were non-toxic at the concentrations tested at 24h and 8 days and 0.5 mg/mL MO and MY alone reduced cell viability at 48h. ALP activity and deposition of MN were increased for MO+MY combination and CH in MDPC-23 cells. 7 days hydrogel extracts containing or not MO+MY were not cytotoxic up to 25% dilution at 48h and at low concentrations stimulated ALP activity and MN deposition at 8 and 14 days of evaluation. In conclusion, the combination of morin and myricetin incorporated or not in CPG hydrogels presented antibiofilm effect on oral pathogens and low cytotoxicity on fibroblasts. Morin myricetin at low concentrations, alone, in combination or in CPG hydrogels were not cytotoxic and were effective in inducing mineralization markers in odontoblast-like cells(AU)

Histomorphometry evaluation of bone anabolism promoted by prostaglandin E1 and its relation to hypercalcemia / Evaluación histomorfométrica del anabolismo óseo en la reparación promovida por la prostaglandina E1 y su relación con la hipercalcemia

Abstract Background: At present, parathyroid hormone is the only existing anabolic bone therapy but produces hypercalcemia. Prostaglandin E1 (PGE1) has been suggested as a bone anabolic agent that allows bone modeling formation without producing hypercalcemia. This study aimed to corroborate these PGE1 properties. Methods: For 22 days, rabbits (n = 30) were divided into three groups (n = 10 each group) and received intravenous solutions: vehicle (control group), palate disjunction + vehicle (sham group), and palate disjunction + 50 mg of PGE1 (PGE1 group). On days 1, 3, and 22, palatine suture X-rays were taken. On day 22, bone formation markers were analyzed, and the rabbits were sacrificed. Bone palate undecalcified samples were processed. Histomorphometry software was used to analyze bone parameters, and the mineralization front was stained with toluidine blue. Scalloped lines reflect remodeling-based bone formation (RBF), and smooth lines reflect modeling-based formation (MBF). Results: X-rays showed more significant palatal disjunction in the PGE1 group; this group exhibited significant calcitriol serum increments. Hypercalciuria was observed in the PGE1 group, and resorption markers (N-telopeptides) remained stable. Sutural bones in the PGE1 group exhibited significant anabolism in structural parameters. RBF was 20%, and MBF was 6% in the sham group; in the PGE1 group, RBF was 8.6%, and MBF was 17%. In the PGE1 group, mineralization was significantly accelerated, but resorption remained stable. Conclusions: This model suggests that PGE1 favors palate disjunction, calcitriol synthesis, and shortens the mineralization. Therefore, PGE1 is an important bone anabolic molecule predominantly of modeling-based form and no hypercalcemia.

Resumen Introducción: La hormona paratiroidea es la única molécula anabólica ósea, pero ocasiona hipercalcemia. La prostaglandina E1 (PGE1) sugiere ser un anabólico óseo con formación por modelación predominante y generalmente no ocasiona hipercalcemia. El objetivo de este estudio fue corroborar estas propiedades de la PGE1. Métodos: Por 22 días, 30 conejos divididos en tres grupos (n = 10 cada grupo) recibieron una solución por vía intravenosa: vehículo (grupo control), disyunción palatina más vehículo (grupo sham) y disyunción palatina más 50 mg de PGE1 (grupo PGE1). A los días 1, 3 y 22 se obtuvieron radiografías de la sutura palatina. En el día 22 se analizaron los marcadores bioquímicos de formación ósea y se sacrificó a los conejos. Las suturas y los huesos suturales se procesaron sin descalcificar. La evaluación histomorfométrica fue digitalizada y el frente de mineralización ósea se tiñó con azul de toluidina. Las líneas irregulares reflejan resorción (remodelación) y las líneas rectas no resorción (modelación). Resultados: Radiográficamente, la disyunción palatina fue mayor en el grupo PGE1. Este grupo mostró una hipercalcitonemia significativa, pero la calcemia y los marcadores resortivos (N-telopéptidos) se mantuvieron estables. Por histomorfometría, los huesos suturales del grupo PGE1 mostraron anabolismo significativo en parámetros estructurales. En el grupo sham, la remodelación ósea fue del 20% y la modelación fue del 6%; en el grupo PGE1, la remodelación fue del 8.6% y la modelación fue del 17%. En este mismo grupo, la mineralización fue significativamente acelerada, pero la resorción se mantuvo igual. Conclusiones: Este modelo sugiere que la PGE1 favorece la disyunción palatina y el aumento del calcitriol, y acelera la mineralización y el anabolismo óseo por modelación predominante sin hipercalcemia.

Study of rrPDGF-BB gene modified BMSCs in promoting distraction osteogenesis of rat femur / 中华显微外科杂志

Objective:To investigate the therapeutic effect of rat bone marrow mesenchymal stem cells (BMSCs) transfected with recombinant rat platelet-derived growth factor BB (rrPDGF-BB) gene on the distraction osteogenesis.Methods:From October, 2019 to June, 2020, 48 batches of BMSCs were cultured from 48 young SD rats, 24 of which were transfected with rrPDGF-BB gene by lentivirus. Meanwhile, other 72 male adult SD rats were randomly selected to establish the right femoral distraction osteogenesis model. The rats were equally divided into 3 groups. PBS, BMSCs without intervention and BMSCs transfected with rrPDGF-BB gene were injected into the distraction space of each group of rats assigned as Blank group, Negative group and Experimental group, respectively. Results of the experiment were evaluated by means of imaging and immunohistochemistry. P<0.05 indicated a statistically significant difference. Results:The cultured BMSCs grew well. The expression of CD34(0.1%) and CD45(2.8%) in the third generation of BMSCs was low, and that of CD29 (95.1%) was high, which was consistent with the phenotype of BMSCs described in literatures. After transfection, the expression of green fluorescence gradually increased with the extension of transfection time, confirming the success of transfection. After 14 days, all rats reached the expected distance of distraction. The rats were observed at assigned time points in 2, 4 and 8 weeks. The photos of femur specimen showed that continuous callus could be seen in the experimental group, the hardness and colour were close to the normal bone tissue, and the activity of the distraction space was poor, which was lower than that of the blank group. X-ray examination showed that there were more new callus in the experimental group, and the bone marrow cavity was re-canalized earlier than that of the blank group; Micro-CT examination, in sagittal plane, showed that the distraction space of the experimental group healed well, the broken end was connected, and the recanalization of bone marrow cavity was earlier than that of the blank group; Micro-CT parameters of each group showed that trabecular thickness[(0.297±0.005) mm], trabecular number [(1.663±0.032) mm], bone volume fraction[(59.832±2.187)%] and bone mineral density[(0.586±0.014) g/cm 3] of the experimental group were the greatest, while trabecular separation[(0.399±0.051) mm] of the experimental group was the smallest. There was statistical difference between each group( P < 0.05); HE staining and VEGF immunohistochemistry showed that the vessels and chondrocytes formed earlier and were more in the experimental group than that in the blank group. In 8 weeks, the new callus joined into one piece under the microscope in the experimental group, and the bone marrow cavity was re-canalized with a large number of red blood cells. Conclusion:Studies have shown that BMSCs transfected with rrPDGF-BB gene can promote the formation of callus in the distraction area of rats, shorten the mineralisation time of new callus, and promote the maturation of new bone in the area of distraction osteogenesis.

Expert consensus on clinical management of metabolic bone disease of prematurity (2021) / 中国当代儿科杂志

Metabolic bone disease of prematurity (MBDP) is a systemic bone disease with a reduction in bone mineral content due to disorder of calcium and phosphorus metabolism. There is still a lack of in-depth research and systematic understanding of MBDP in China, and there are many irregularities in clinical management of this disease. Based on relevant studies in China and overseas, Grading of Recommendations Assessment, Development and Evaluation was used to develop the expert consensus on the clinical management of MBDP, which provides recommendations from the following five aspects: high-risk factors, screening/diagnosis, prevention, treatment, and post-discharge follow-up of MBDP, so as to provide relevant practitioners with recommendations on the clinical management of MBDP to reduce the incidence rate of MBDP and improve its short- and long-term prognosis.