Mesenchymal stem cells-derived extracellular vesicles protect against oxidative stress-induced xenogeneic biological root injury via adaptive regulation of the PI3K/Akt/NRF2 pathway.

Xenogeneic extracellular matrices (xECM) for cell support have emerged as a potential strategy for addressing the scarcity of donor matrices for allotransplantation. However, the poor survival rate or failure of xECM-based organ transplantation is due to the negative impacts of high-level oxidative stress and inflammation on seed cell viability and stemness. Herein, we constructed xenogeneic bioengineered tooth roots (bio-roots) and used extracellular vesicles from human adipose-derived mesenchymal stem cells (hASC-EVs) to shield bio-roots from oxidative damage. Pretreatment with hASC-EVs reduced cell apoptosis, reactive oxygen species generation, mitochondrial changes, and DNA damage. Furthermore, hASC-EV treatment improved cell proliferation, antioxidant capacity, and odontogenic and osteogenic differentiation, while significantly suppressing oxidative damage by activating the phosphatidylinositol 3-kinase (PI3K)/Akt pathway and nuclear factor erythroid 2 (NFE2)-related factor 2 (NRF2) nuclear translocation via p62-associated Kelch-like ECH-associated protein 1 (KEAP1) degradation. Inhibition of PI3K/Akt and Nrf2 knockdown reduced antioxidant capacity, indicating that the PI3K/Akt/NRF2 pathway partly mediates these effects. In subcutaneous grafting experiments using Sprague-Dawley rats, hASC-EV administration significantly enhanced the antioxidant effect of the bio-root, improved the regeneration efficiency of periodontal ligament-like tissue, and maximized xenograft function. Conclusively, therefore, hASC-EVs have the potential to be used as an immune modulator and antioxidant for treating oxidative stress-induced bio-root resorption and degradation, which may be utilized for the generation and restoration of other intricate tissues and organs.

Biomimetic, biodegradable and osteoinductive treated dentin matrix/α-calcium sulphate hemihydrate composite material for bone tissue engineering.

It is still a huge challenge for bone regenerative biomaterial to balance its mechanical, biological and biodegradable properties. In the present study, a new composite material including treated dentin matrix (TDM) and α-calcium sulphate hemihydrate (α-CSH) was prepared. The optimal composition ratio between TDM and α-CSH was explored. The results indicate that both components were physically mixed and structurally stable. Its compressive strength reaches up to 5.027 ± 0.035 MPa for 50%TDM/α-CSH group, similar to human cancellous bone tissues. Biological experiments results show that TDM/α-CSH composite exhibits excellent biocompatibility and the expression of osteogenic related genes and proteins (ALP, RUNX2, OPN) is significantly increased. In vivo experiments suggest that the addition of TDM for each group (10%, 30%, 50%) effectively promotes cell proliferation and osteomalacia. In addition, 50% of the TDM/α-CSH combination displays optimal osteoconductivity. The novel TDM/α-CSH composite is a good candidate for certain applications in bone tissue engineering.

TSF/FHA induces osteogenic differentiation of Mc3t3 cells via Pygo2 dependent Wnt/ß-catenin signaling pathway.

OBJECTIVES: This study aimed to investigate whether tussah silk fibroin (TSF)/fluoridated hydroxyapatite (FHA) can promote osteogenic differentiation of Mc3t3 cells and explore the role of Wnt/ß-catenin signaling in this process. METHODS: TSF/FHA was gained via freeze drying technique and cyclic phosphate immersion method. The relative expression levels of bone-related genes and proteins of Mc3t3 cells seeded on different materials were examined by RT-qPCR and Western blotting. Knockdown or overexpression of Pygo2 in Mc3t3 cells was achieved using lentiviral transfection. Cell proliferation, the expression of bone-related genes and proteins were subsequently examined. Animal experiment was also performed to observe the osteogenesis effect. RESULTS: Different ratios of fluorine of TSF/FHA accelerated the osteogenic differentiation of Mc3t3 cells and increased the Pygo2 expression. The Wnt/ß-catenin signaling pathway was activated after TSF/FHA induction, accompanied by the increased expression of related genes. In SD rats with skull defect, the newly formed bone increased significantly and the Pygo2 overexpressing Mc3t3 cells promoted osteogenesis. However, Pygo2 knockdown markedly compromised the osteogenesis of Mc3t3 cells after TSF/FHA induction. CONCLUSION: TSF/FHA facilitates osteogenic differentiation of Mc3t3 cells via upregulating Pygo2 and activating Wnt/ß-catenin signaling pathway.

Is there an epilepsy belt of high prevalence rate in China?

Background: Epilepsy is one of the leading neurological diseases. Our study is aimed to determine whether there is a focal region of high epilepsy prevalence in China. Methods: All studies published between 1981 and 2020 investigating the prevalence of epilepsy in China were systematically reviewed. The geographical location, sample size, number of cases, urbanization rate, gross domestic product (GDP) per capita, percentage of <15 years old, and medical insurance per capita were derived and analyzed. Criteria for a provincial region of high prevalence was defined as with higher epilepsy prevalence than the average prevalence of epilepsy in China. Results: A total of 60 studies provided data on the prevalence of epilepsy in 29 of 33 provincial regions of China. The average prevalence in China was 1.68 per 1,000, and 12 provincial regions met our criteria for a region of high epilepsy prevalence and constitute an epilepsy belt ranging along the division between the second step and the third step of China. The prevalence in the epilepsy belt was 331.9 per 100,000 population compared with 125.3 per 100,000 in regions outside the belt (P < 0.05). Surprisingly, there was no significant difference in sample size, number of cases, urbanization rate, GDP per capita, percentage of <15 years old, or medical insurance per capita between the regions in and outside the epilepsy belt. Conclusions: An epilepsy belt of high prevalence exists in 12 provincial regions locating along the division between the second step and the third step of China.

α-Hemihydrate calcium sulfate/n-hydroxyapatite combined with metformin promotes osteogenesis in vitro and in vivo.

This study aimed to examine the effects of loading different concentrations of metformin onto an α-hemihydrate calcium sulfate/nano-hydroxyapatite (α-CSH/nHA) composite. The material characteristics, biocompatibility, and bone formation were compared as functions of the metformin concentration. X-ray diffraction results indicated that the metformin loading had little influence on the phase composition of the composite. The hemolytic potential of the composite was found to be low, and a CCK-8 assay revealed only weak cytotoxicity. However, the metformin-loaded composite was found to enhance the osteogenic ability of MC3T3-E1 cells, as revealed by alkaline phosphate and alizarin red staining, real-time PCR, and western blotting, and the optimal amount was 500 µM. RNA sequencing results also showed that the composite material increased the expression of osteogenic-related genes. Cranial bone lacks muscle tissue, and the low blood supply leads to poor bone regeneration. As most mammalian cranial and maxillofacial bones are membranous and of similar embryonic origin, the rat cranial defect model has become an ideal animal model for in vivo experiments in bone tissue engineering. Thus, we introduced a rat cranial defect with a diameter of 5 mm as an experimental defect model. Micro-computed tomography, hematoxylin and eosin staining, Masson staining, and immunohistochemical staining were used to determine the effectiveness of the composite as a scaffold in a rat skull defect model. The composite material loaded with 500 µM of metformin had the strongest osteoinduction ability under these conditions. These results are promising for the development of new methods for repairing craniofacial bone defects.

Treated dentin matrix induces odontogenic differentiation of dental pulp stem cells via regulation of Wnt/ß-catenin signaling.

Treated dentin matrix (TDM) is an ideal scaffold material containing multiple extracellular matrix factors. The canonical Wnt signaling pathway is necessary for tooth regeneration. Thus, this study investigated whether the TDM can promote the odontogenic differentiation of human dental pulp stem cells (hDPSCs) and determined the potential role of Wnt/ß-catenin signaling in this process. Different concentrations of TDM promoted the dental differentiation of the hDPSCs and meanwhile, the expression of GSK3ß was decreased. Of note, the expression of the Wnt/ß-catenin pathway-related genes changed significantly in the context of TDM induction, as per RNA sequencing (RNA seq) data. In addition, the experiment showed that new dentin was visible in rat mandible cultured with TDM, and the thickness was significantly thicker than that of the control group. In addition, immunohistochemical staining showed lower GSK3ß expression in new dentin. Consistently, the GSK3ß knockdown hDPSCs performed enhanced odotogenesis compared with the control groups. However, GSK3ß overexpressing could decrease odotogenesis of TDM-induced hDPSCs. These results were confirmed in immunodeficient mice and Wistar rats. These suggest that TDM promotes odontogenic differentiation of hDPSCs by directly targeting GSK3ß and activating the canonical Wnt/ß-catenin signaling pathway and provide a theoretical basis for tooth regeneration engineering.

[Study on the relation of transmission of Lyme disease and ecological protection from western regions in China].

OBJECTIVE: To find out the relationship of ecological environment protection and the transmission of Lyme disease under economic development of western regions in China. METHODS: Both scene molecular and traditional epidemiological methods were used to assess the effects of environmental protection on the transmission of Lyme disease. RESULTS: Among areas as protected natural forests, semi-protected nursery forests and farmland, the vector tick species and reservoir rodents from protected natural forests area had the highest quantity of population and diversity index and followed by semi-protected nursery forests. Vector competence of reservoir hosts and value of natural foci from protected natural forests area were also remarkably higher than those areas of semi-protected nursery forests and farmland. Staff working in the areas who were bitten by ticks from protected natural forests areas had higher serological positive rate (66.7%) than those from semi-protected nursery forests areas (2.5%), and both showed remarkable difference (P = 6.45, E-11 < 0.01, df = 1). The difference of genetic divergence among these subpopulations from different habitats being surveyed showed that the biggest genetic divergence index (F(st)) of 0.557 42 was between protected natural forests area and farmland area. The index between semi-protected nursery forests area and farmland area was also bigger than zero with statistical significance. The genetic divergence index of 0.108 02 between semi-protected nursery forests area and protected natural forests area was the lowest which showed that genetic divergence between the subpopulations of the two sampling areas was not obvious. The genetic distance among these subpopulations had similar change along with their habitats. CONCLUSION: Under economic development of western regions in China, when programs as natural forests protections, recovery prairie and grassland from farmland were actively performed, vectors insects and reservoir hosts of Lyme disease might also be protected to some degree but the risk and value of natural foci on Lyme disease might increase. Data suggested that people entering these areas should be told to strengthen their awareness on individual protection against the disease.