MSCs overexpressing GDNF restores brain structure and neurological function in rats with intracerebral hemorrhage.

Mesenchymal stem cells (MSCs) have been applied in transplantation to treat intracerebral hemorrhage (ICH) but with limited efficacy. Accumulated evidence has shown that glial cell-derived neurotrophic factor (GDNF) plays a crucial part in neuronal protection and functional recovery of the brain after ICH; however, GDNF has difficulty crossing the blood-brain barrier, which limits its application. In this study, we investigated the influences of MSCs overexpressing GDNF (MSCs/GDNF) on the brain structure as well as gait of rats after ICH and explored the possible mechanisms. We found that cell transplantation could reverse the neurological dysfunction and brain damage caused by ICH to a certain extent, and MSCs/GDNF transplantation was superior to MSCs transplantation. Moreover, Transplantation of MSCs overexpressing GDNF effectively reduced the volume of bleeding foci and increased the level of glucose uptake in rats with ICH, which could be related to improving mitochondrial quality. Furthermore, GDNF produced by transplanted MSCs/GDNF further inhibited neuroinflammation, improved mitochondrial quality and function, promoted angiogenesis and the survival of neurons and oligodendrocytes, and enhanced synaptic plasticity in ICH rats when compared with simple MSC transplantation. Overall, our data indicate that GDNF overexpression heightens the curative effect of MSC implantation in treating rats following ICH.

Evaluating the effects of policies on building construction waste management: a hybrid dynamic approach.

The construction industry, as a vital pillar of a country's economy, generates a significant amount of construction waste, which places a tremendous burden on the environment and society. Although previous studies have explored the impact of policies on construction waste management, there is a lack of a simulation model that can be easily used, taking into account the dynamic nature, generality, and practicability of the model. To fill this gap, a hybrid dynamics model of construction waste management system is developed using agent-based modeling, system dynamics, perceived value, and experienced weighted attraction. Based on relevant data from the construction waste industry in Shenzhen, China, the effect of five policies on contractor strategy selection and overall evolution is tested. The results indicate that industry rectification policy and combination policy can effectively promote the resource treatment of construction waste and reduce illegal dumping, pollution to the environment of waste and treatment process, and waste treatment cost. The findings of this research will help not only researchers better analyze the effect of construction waste policies but also policymakers and practitioners in proposing effective construction waste management policies.

Decreased Porphyromonas gingivalis adhesion and improved biocompatibility on tetracycline-loaded TiO2 nanotubes: an in vitro study.

BACKGROUND: Titanium dioxide (TiO2) nanotubes are often used as carriers for loading materials such as drugs, proteins, and growth factors. MATERIALS AND METHODS: In this study, we loaded tetracycline onto TiO2 nanotubes to demonstrate its antibacterial properties and biocompatibility. The two-layered anodic TiO2 nanotubes with a honeycomb-like porous structure were fabricated by using a two-step anodization, and they were loaded with tetracycline by using a simplified lyophilization method and vacuum drying. Their physical properties, such as chemical compositions, wettability, and surface morphologies of the different samples, were observed and measured by X-ray photoelectron spectroscopy (XPS), contact angle measurement, and scanning electron microscopy (SEM). The in vitro growth behaviors of mouse bone marrow stromal cells (BMSCs) on these substrates were investigated. RESULTS: The TiO2 nanotube (NT) substrates and the tetracycline-loaded TiO2 nanotube (NT-T) substrates revealed a crucial potential for promoting the adhesion, proliferation, and differentiation of BMSCs. Similarly, the NT-T substrates displayed a sudden release of tetracycline in the first 15 minutes of their administration, and the release tended to be stable 90 minutes later. The antibacterial performances of the prepared substrates were assessed with Porphyromonas gingivalis. The result showed that NT and NT-T substrates had antibacterial capacities. CONCLUSION: Overall, this research provides a promising method with potential for clinical translation by allowing local slow release of antimicrobial compounds by loading them onto constructed nanotubes.

[TiO2nanotubes functionalized with recombinant human bone morphogenetic protein-2 enhance biological activity in vitro].

OBJECTIVE: To investigate the effect of TiO2nanotube arrays covalently modified by recombinant human bone morphogenetic protein- 2(rhBMP- 2) on the early bioactivity of mesenchymal stem cells (MSC) in vitro and to provide experimental evidence for the biochemical modification of titanium implants. METHODS: In the experiment group, double titanium nanotube arrays were prepared by anodization, and were chemically grafted with rhBMP- 2. Mechanically polished pure titanium was used as blank control group, and titanium dioxide nanotubes was used as negative control A group, and titanium dioxide nanotubes + carbonyldiimidazole as negative control B group. Field emission scanning electron microscope (FE- SEM) and X- ray photoelectron spectroscopy (XPS) were used to detect the morphology and physicochemical properties of the experiment group, blank control group and the negative control group. Cell adhesion on the specimen surface of the experiment group, blank control group and negative control group on the 1st day was tested. Cell proliferation on the 1st, 3rd and 5th day and alkaline phosphatase activity on the 5th, 7th and 11th day was also tested. RESULTS: FE- SEM showed that the surface of titanium nanotubes loaded with rhBMP- 2 possessed visible miliary particulate matter. XPS showed that nitrogen peak in the group of titanium nanotubes loaded with rhBMP-2 was significantly greater that those in the other groups. FE- SEM showed that the cells on the surface of the experimental group on the 1st day spread well, better than those in the control group and negative control group. Cell proliferation activity on the 1st day in different groups was not obvious (P>0.05), the A value of the experimental group on the 3rd and 5th day (3.295 ± 0.153, 3.823 ± 0.059) were significantly higher than those in the control group (2.479 ± 0.064, 3.131 ± 0.096) and negative control A group (2.715 ± 0.075, 3.371 ± 0.047) and negative control B group (2.756 ± 0.132, 3.637 ± 0.047) (P<0.05). Alkaline phosphatase activity on the 5th, 7th and 11th day in the experimental group (0.0477 ± 0.0287, 0.0615 ± 0.0016, 0.0667 ± 0.0018) were better than those in the control group, negative control A group and negative control B group (P<0.05). CONCLUSIONS: Titanium nanotube arrays can be loaded with rhBMP-2 by biochemical methods and have good biocompatibility.