Dynamic hydrogel-metal-organic framework system promotes bone regeneration in periodontitis through controlled drug delivery.

Periodontitis is a prevalent chronic inflammatory disease, which leads to gradual degradation of alveolar bone. The challenges persist in achieving effective alveolar bone repair due to the unique bacterial microenvironment's impact on immune responses. This study explores a novel approach utilizing Metal-Organic Frameworks (MOFs) (comprising magnesium and gallic acid) for promoting bone regeneration in periodontitis, which focuses on the physiological roles of magnesium ions in bone repair and gallic acid's antioxidant and immunomodulatory properties. However, the dynamic oral environment and irregular periodontal pockets pose challenges for sustained drug delivery. A smart responsive hydrogel system, integrating Carboxymethyl Chitosan (CMCS), Dextran (DEX) and 4-formylphenylboronic acid (4-FPBA) was designed to address this problem. The injectable self-healing hydrogel forms a dual-crosslinked network, incorporating the MOF and rendering its on-demand release sensitive to reactive oxygen species (ROS) levels and pH levels of periodontitis. We seek to analyze the hydrogel's synergistic effects with MOFs in antibacterial functions, immunomodulation and promotion of bone regeneration in periodontitis. In vivo and in vitro experiment validated the system's efficacy in inhibiting inflammation-related genes and proteins expression to foster periodontal bone regeneration. This dynamic hydrogel system with MOFs, shows promise as a potential therapeutic avenue for addressing the challenges in bone regeneration in periodontitis.

High-Frequency Ultrasound for Long-term Safety Assessment of Poly-L-Lactic Acid Facial Filler.

BACKGROUND: Injectable poly- l -lactic acid (PLLA) is a new type of biodegradable dermal filler that has been utilized for soft tissue filling. However, there is no convenient and reliable method to assess the long-term safety of PLLA filler. OBJECTIVE: To assess the long-term safety of PLLA injection into nasolabial folds by high-frequency ultrasound and to select the ultrasonic probes with the most appropriate frequency. MATERIALS AND METHODS: After a 30-month PLLA injection into the deep dermis of the nasolabial fold, subjects were examined by high-frequency ultrasound with the 20 MHz and 50 MHz probes. RESULTS: Twenty subjects with nasolabial fold contour deficiency were enrolled in this study. After a 30-month PLLA injection in nasolabial folds, PLLA degraded entirely in 16 subjects (16/20, 80%), and abnormal echo in the skin was observed in 4 subjects (4/20, 20%) caused by undegraded PLLA microparticles, PLLA microparticles deposition, fibrous nodules, and granuloma. The 20-MHz probe is more appropriate than the 50-MHz probe for evaluating the adverse effects of PLLA injection. CONCLUSION: High-frequency ultrasound is a rapid, reliable, and noninvasive method to monitor the degradation condition of PLLA and the formation of papules and nodules associated with PLLA injection.

Glycoprotein A repetitions predominant (GARP) positively regulates transforming growth factor (TGF) ß3 and is essential for mouse palatogenesis.

Glycoprotein A repetitions predominant (GARP) (encoded by the Lrrc32 gene) plays important roles in cell-surface docking and activation of TGFß. However, GARP's role in organ development in mammalian systems is unclear. To determine the function of GARP in vivo, we generated a GARP KO mouse model. Unexpectedly, the GARP KO mice died within 24 h after birth and exhibited defective palatogenesis without apparent abnormalities in other major organs. Furthermore, we observed decreased apoptosis and SMAD2 phosphorylation in the medial edge epithelial cells of the palatal shelf of GARP KO embryos at embryonic day 14.5 (E14.5), indicating a defect in the TGFß signaling pathway in the GARP-null developing palates. Of note, the failure to develop the secondary palate and concurrent reduction of SMAD phosphorylation without other defects in GARP KO mice phenocopied TGFß3 KO mice, although GARP has not been suggested previously to interact with TGFß3. We found that GARP and TGFß3 co-localize in medial edge epithelial cells at E14.5. In vitro studies confirmed that GARP and TGFß3 directly interact and that GARP is indispensable for the surface expression of membrane-associated latent TGFß3. Our findings indicate that GARP is essential for normal morphogenesis of the palate and demonstrate that GARP plays a crucial role in regulating TGFß3 signaling during embryogenesis. In conclusion, we have uncovered a novel function of GARP in positively regulating TGFß3 activation and function.

Advances in pH-Sensitive Polymers for Smart Insulin Delivery.

Since diabetes mellitus has become one of the most serious threats to human health, researchers have been designing new drugs and developing new technologies to control the blood glucose level (BGL) while improving patient compliance. In addition to the traditional subcutaneous injection method, alternative routes of insulin delivery have been investigated and tested, including oral, pulmonary, transdermal, and nasal. The final goal of all these technologies is to develop a system that releases insulin in a controlled manner depending on the BGL. pH-Sensitive polymers appear to be good candidates to achieve this goal because they exhibit a conformational transition when the pH in the surrounding medium fluctuates, which changes the solubility of the polymers and leads to the swelling of hydrogels. Many pH-sensitive polymers, such as poly(2-dimethylamino)ethylmethacrylate) and natural biopolymers such as chitosan, have been used in different delivery systems. This review focuses on the most commonly used pH-sensitive polymers and their applications in insulin delivery systems. In particular, the relationship between the chemical structure of the polymeric systems and their insulin delivery performance is discussed.

A novel bi-layered asymmetric membrane incorporating demineralized dentin matrix accelerates tissue healing and bone regeneration in a rat skull defect model.

Objectives: The technique of guided bone regeneration (GBR) has been widely used in the field of reconstructive dentistry to address hard tissue deficiency. The objective of this research was to manufacture a novel bi-layered asymmetric membrane that incorporates demineralized dentin matrix (DDM), a bioactive bone replacement derived from dentin, in order to achieve both soft tissue isolation and hard tissue regeneration simultaneously. Methods: DDM particles were harvested from healthy, caries-free permanent teeth. The electrospinning technique was utilized to synthesize bi-layered DDM-loaded PLGA/PLA (DPP) membranes. We analyzed the DPP bilayer membranes' surface topography, physicochemical properties and degradation ability. Rat skull critical size defects (CSDs) were constructed to investigate in vivo bone regeneration. Results: The synthesized DPP bilayer membranes possessed suitable surface characteristics, acceptable mechanical properties, good hydrophilicity, favorable apatite forming ability and suitable degradability. Micro-computed tomography (CT) showed significantly more new bone formation in the rat skull defects implanted with the DPP bilayer membranes. Histological evaluation further revealed that the bone was more mature with denser bone trabeculae. In addition, the DPP bilayer membrane significantly promoted the expression of the OCN matrix protein in vivo. Conclusions: The DPP bilayer membranes exhibited remarkable biological safety and osteogenic activity in vivo and showed potential as a prospective candidate for GBR applications in the future.

Efficient Treatment of Pulpitis via Transplantation of Human Pluripotent Stem Cell-Derived Pericytes Partially through LTBP1-Mediated T Cell Suppression.

Dental pulp pericytes are reported to have the capacity to generate odontoblasts and express multiple cytokines and chemokines that regulate the local immune microenvironment, thus participating in the repair of dental pulp injury in vivo. However, it has not yet been reported whether the transplantation of exogenous pericytes can effectively treat pulpitis, and the underlying molecular mechanism remains unknown. In this study, using a lineage-tracing mouse model, we showed that most dental pulp pericytes are derived from cranial neural crest. Then, we demonstrated that the ablation of pericytes could induce a pulpitis-like phenotype in uninfected dental pulp in mice, and we showed that the significant loss of pericytes occurs during pupal inflammation, implying that the transplantation of pericytes may help to restore dental pulp homeostasis during pulpitis. Subsequently, we successfully generated pericytes with immunomodulatory activity from human pluripotent stem cells through the intermediate stage of the cranial neural crest with a high level of efficiency. Most strikingly, for the first time we showed that, compared with the untreated pulpitis group, the transplantation of hPSC-derived pericytes could substantially inhibit vascular permeability (the extravascular deposition of fibrinogen, ** p < 0.01), alleviate pulpal inflammation (TCR+ cell infiltration, * p < 0.05), and promote the regeneration of dentin (** p < 0.01) in the mouse model of pulpitis. In addition, we discovered that the knockdown of latent transforming growth factor beta binding protein 1 (LTBP1) remarkably suppressed the immunoregulation ability of pericytes in vitro and compromised their in vivo regenerative potential in pulpitis. These results indicate that the transplantation of pericytes could efficiently rescue the aberrant phenotype of pulpal inflammation, which may be partially due to LTBP1-mediated T cell suppression.

Generation of a MSX1 knockout human embryonic stem cell line using CRISPR/Cas9 technology.

The MSX1 gene encodes a transcriptional repressor and plays important roles in limb-pattern formation, craniofacial development, and odontogenesis during vertebrate embryogenesis. Previous studies demonstrated that human MSX1 mutations are associated with tooth agenesis, orofacial clefting, and nail dysplasia. Here, we generated a MSX1 knockout cell line from human embryonic stem cell (hESC) line (H9) by CRISPR/cas9-mediated gene targeting. This cell line may serve as a valuable in vitro cell model for MSX1 mutation-related diseases and help to gain more insight into the biological function of MSX1.

Comparison of the osteogenic effectiveness of an autogenous demineralised dentin matrix and Bio-Oss® in bone augmentation: a systematic review and meta-analysis.

This study aimed to evaluate the clinical efficacy and histological outcomes of autogenous demineralised dentin matrix (ADDM) as bone graft material compared with Bio-Oss® in bone augmentation for the treatment of patients with oral bone deficits. Eight databases (PubMed, EMBASE, Cochrane Library, Science Direct, Scopus, Web of Science, CNKI, and WFPD) were searched for randomised controlled trials (RCT) performed from the date of inception of each database to July 2021. The Cochrane Collaboration's risk assessment tool was used to conduct the methodological quality assessment. Stata 15.0 software was used to perform data analysis. Seven RCTs including 220 patients were considered eligible for this study. No significant difference was found in the percentage of new bone formation (NBF) and implant stability quotient (ISQ). Patients who received ADDM grafting showed a significantly lower sinus height (SH) and percentage of residual graft material (RGM) compared with Bio-Oss® grafting. ADDM is as effective as Bio-Oss® in bone augmentation for oral bone defects.

High abundance of microplastics in groundwater in Jiaodong Peninsula, China.

The occurrence of microplastics (MPs, <5 mm) in drinking water has aroused extensive concerns, whereas our understanding of their presence in groundwater, a major source of drinking water, is still limited. The present study investigated the occurrence of microplastics in groundwater sampled from five sites in Jiaodong Peninsula, China. The abundance, type, and size of MPs in the groundwater samples were determined by Laser Direct Infrared following a well-established and quality-controlled analytical route. Notably, MPs were detected in groundwater across all five sampling sites, with high abundances ranging from 87 to 6832 particles/L and an average abundance of 2103 particles/L. The variation of the abundance of MPs was correlated to the distances between sampling sites and anthropogenic activities, which suggested significant impacts of aboveground industry and agriculture on the abundance of MPs in groundwater. Polyethylene terephthalate (PET) and polyurethane (PU) were the dominant polymer types detected in all groundwater samples. The MPs with a size smaller than 100 µm were found to account for >90% of the total MPs detected in four sampling sites, which was likely associated with their migratory routes through surface water runoff and infiltration into the groundwater settings. The results of this study suggest the importance of counting small MPs when determining their abundances in groundwater or their abundances would be considerably underestimated. The present study for the first time demonstrated the occurrence of MPs in groundwater in China, which improves our understanding of the MPs distribution and raises concerns about groundwater safety in terms of MPs pollution.

The Combination of Paraformaldehyde and Glutaraldehyde Is a Potential Fixative for Mitochondria.

Mitochondria are highly dynamic organelles, constantly undergoing shape changes, which are controlled by mitochondrial movement, fusion, and fission. Mitochondria play a pivotal role in various cellular processes under physiological and pathological conditions, including metabolism, superoxide generation, calcium homeostasis, and apoptosis. Abnormal mitochondrial morphology and mitochondrial protein expression are always closely related to the health status of cells. Analysis of mitochondrial morphology and mitochondrial protein expression in situ is widely used to reflect the abnormality of cell function in the chemical fixed sample. Paraformaldehyde (PFA), the most commonly used fixative in cellular immunostaining, still has disadvantages, including loss of antigenicity and disruption of morphology during fixation. We tested the effect of ethanol (ETHO), PFA, and glutaraldehyde (GA) fixation on cellular mitochondria. The results showed that 3% PFA and 1.5% GA (PFA-GA) combination reserved mitochondrial morphology better than them alone in situ in cells. Mitochondrial network and protein antigenicity were well maintained, indicated by preserved MitoTracker and mitochondrial immunostaining after PFA-GA fixation. Our results suggest that the PFA-GA combination is a valuable fixative for the study of mitochondria in situ.

Recent advances in functional nanostructured materials for bone-related diseases.

Bone-related diseases seriously threaten people's health and research studies have been dedicated towards searching for new and effective treatment methods. Nanotechnologies have opened up a new field in recent decades and nanostructured materials, which exist in a variety of forms, are considered to be promising materials in this field. This article reviews the most recent progress in the development of nanostructured materials for bone-related diseases, including osteoporosis, osteoarthritis, bone metastasis, osteomyelitis, myeloma, and bone defects. We highlight the advantages and functions of nanostructured materials, including sustained release, bone targeting, scaffolding in bone tissue engineering, etc., in bone-related diseases. We also include the remaining challenges of these emerging materials.

The relationship of PTH Bst BI polymorphism, calciotropic hormone levels, and dental fluorosis of children in China.

The aim of this study was to explore the association of parathyroid hormone (PTH) gene Bst BI polymorphism, calciotropic hormone levels, and dental fluorosis of children. A case-control study was conducted in two counties (Kaifeng and Tongxu) in Henan Province, China in 2005-2006. Two hundred and twenty-five children were recruited and divided into three groups including dental fluorosis group (DFG), non-dental fluorosis group (NDFG) from high fluoride areas, and control group (CG). Urine fluoride content was determined using fluoride ion selective electrode; PTH Bst BI were genotyped using PCR-RFLP; osteocalcin (OC) and calcitonin (CT) levels in serum were detected using radioimmunoassay. Genotype distributions were BB 85.3% (58/68), Bb 14.7% (10/68) for DFG; BB 77.6% (52/67), Bb 22.4% (15/67) for NDFG; and BB 73.3% (66/90), Bb 27.7% (24/90) for CG. No significant difference of Bst BI genotypes was observed among three groups (P > 0.05). Serum OC and urine fluoride of children were both significantly higher in DFG and NDFG than in CG (P < 0.05, respectively), while a similar situation was not observed between DFG and NDFG in high fluoride areas (P > 0.05). Serum OC level of children with BB genotype was significantly higher compared to those with Bb genotype in high fluoride areas (P < 0.05). However, no significant difference of serum CT or calcium (Ca) was observed. In conclusion, there is no correlation between dental fluorosis and PTH Bst BI polymorphism. Serum OC might be a more sensitive biomarker for detecting early stages of dental fluorosis, and further studies are needed.