Development of a new pre-vascularized tissue-engineered construct using pre-differentiated rADSCs, arteriovenous vascular bundle and porous nano-hydroxyapatide-polyamide 66 scaffold

Background: Development of a pre-vascularized tissue-engineered construct with intrinsic vascular system for cell growth and tissue formation still faces many difficulties due to the complexity of the vascular network of natural bone tissue. The present study was to design and form a new vascularized tissue-engineered construct using pre-differentiated rADSCs, arteriovenous vascular bundle and porous nHA-PA 66 scaffold. Methods: rADSCs were pre-differentiated to endothelial cells (rADSCs-Endo) and then incorporated in nHA-PA 66 scaffolds in vitro. Subsequently, in vivo experiments were carried out according to the following groups: Group A (rADSCs-Endo/nHA-PA 66 scaffold with arteriovenous vascular bundle), Group B (rADSCs/nHA-PA 66 scaffold with arteriovenous vascular bundle); Group C (nHA-PA66 scaffold with arteriovenous vascular bundle), Group D (nHA-PA 66 scaffold only). The vessel density and vessel diameter were measured based on histological and immunohistochemical evaluation, furthermore, the VEGF-C, FGF-2 and BMP-2 protein expressions were also evaluated by western blot analysis. Results: The results of in vivo experiments showed that the vessel density and vessel diameter in group A were significantly higher than the other three groups. Between Group B and C, no statistical difference was observed at each time point. In accordance with the results, there were dramatically higher expressions of VEGF-C and FGF-2 protein in Group A than that of Group B, C and D at 2 or 4 weeks. Statistical differences were not observed in VEGF-C and FGF-2 expression between Group B and C. BMP-2 was not expressed in any group at each time point. Conclusions: Compared with muscular wrapping method, arteriovenous vascular bundle implantation could promote vascularization of the scaffold; and the angiogenesis of the scaffold was significantly accelerated when pre-differentiated rADSCs (endothelial differentiation) were added. These positive results implicate the combination of pre-differentiated rADSCs (endothelial differentiation) and arteriovenous vascular bundle may achieve rapidly angiogenesis of biomaterial scaffold

Priming of jasmonate-mediated antiherbivore defense responses in rice by silicon

Although the function of silicon (Si) in plant physiology has long been debated, its beneficial effects on plant resistance against abiotic and biotic stresses, including insect herbivory, have been well documented. In addition, the jasmonate (JA) signaling pathway plays a crucial role in mediating antiherbivore defense responses in plants. However, potential interactions between JA and Si in response to insect attack have not been examined directly. To explore the role JA may play in Si-enhanced resistance, we silenced the expression of allene oxide synthase (OsAOS; active in JA biosynthesis) and CORONATINE INSENSITIVE1 (OsCOI1; active in JA perception) genes in transgenic rice plants via RNAi and examined resulting changes in Si accumulation and defense responses against caterpillar Cnaphalocrocis medinalis (rice leaffolder, LF) infestation. Si pretreatment increased rice resistance against LF larvae in wild-type plants but not in OsAOS and OsCOI1 RNAi lines. Upon LF attack, wild-type plants subjected to Si pretreatment exhibited enhanced defense responses relative to untreated controls, including higher levels of JA accumulation; increased levels of transcripts encoding defense marker genes; and elevated activities of peroxidase, polyphenol oxidase, and trypsin protease inhibitor. Additionally, reduced Si deposition and Si cell expansion were observed in leaves of OsAOS and OsCOI1 RNAi plants in comparison with wild-type plants, and reduced steady-state transcript levels of the Si transporters OsLsi1, OsLsi2, and OsLsi6 were observed in Si-pretreated plants after LF attack. These results suggest a strong interaction between Si and JA in defense against insect herbivores involving priming of JA-mediated defense responses by Si and the promotion of Si accumulation by JA

Comparison between Bipolar Hemiarthroplasty and Total Hip Arthroplasty for Unstable Intertrochanteric Fractures in Elderly Osteoporotic Patients

The present study was conducted to compare bipolar hemiarthroplasty (BA) with total hip arthroplasty (THA) in treatment of unstable intertrochanteric fractures in elderly osteoporotic patients. The THA group included 14 males and 26 females with a mean age of 73.4 years, and the BA group included 27 males and 45 females with a mean age of 76.5 years. Significant difference existed between the two groups in operation time, blood loss, transfusion volume and cost of hospitalization, while no remarkable difference was identified in hospitalization period, general complications, joint function, pain, rate of revision and mortality. No dislocation was observed in BA group while 3 occurred in THA group. The results indicated that for unstable intertrochanteric fractures in elderly osteoporotic patients, BA seems to be a better or more reasonable choice compared with THA for the reason of less blood loss, shorter operation time, lower cost and no dislocation

Role of Silica Nanoparticles in Abiotic and Biotic Stress Tolerance in Plants: A Review

The demand for agricultural crops continues to escalate with the rapid growth of the population. However, extreme climates, pests and diseases, and environmental pollution pose a huge threat to agricultural food production. Silica nanoparticles (SNPs) are beneficial for plant growth and production and can be used as nanopesticides, nanoherbicides, and nanofertilizers in agriculture. This article provides a review of the absorption and transportation of SNPs in plants, as well as their role and mechanisms in promoting plant growth and enhancing plant resistance against biotic and abiotic stresses. In general, SNPs induce plant resistance against stress factors by strengthening the physical barrier, improving plant photosynthesis, activating defensive enzyme activity, increasing anti-stress compounds, and activating the expression of defense-related genes. The effect of SNPs on plants stress is related to the physical and chemical properties (e.g., particle size and surface charge) of SNPs, soil, and stress type. Future research needs to focus on the “SNPs–plant–soil–microorganism” system by using omics and the in-depth study of the molecular mechanisms of SNPs-mediated plant resistance

PAPSS2 promotes alkaline phosphates activity and mineralization of osteoblastic MC3T3-E1 cells by crosstalk and Smads signal pathways.

Several studies have indicated that PAPSS2 (3'-phosphoadenosine-5'-phosphosulfate synthetase 2) activity is important to normal skeletal development. Mouse PAPSS2 is predominantly expressed during the formation of the skeleton and cartilaginous elements of the mouse embryo and in newborn mice. However, the role and mechanism of PAPSS2 in bone formation remains largely unidentified. By analyzing the expression pattern of the PAPSS2 gene, we have found that PAPSS2 is expressed in bone tissue and bone formation. PAPSS2 transcripts increase during osteoblast differentiation and are in less level in RANKL-induced osteoclast like cells. By using lentivirus-mediated RNA interference (RNAi) technology, we knocked down PAPSS2 expression in MC3T3-E1 osteoblast. Silencing of PAPSS2 expression significantly decreases ALP activity and cell mineralization, inhibits expression of osteoblast marker osteopontin (OPN) and collagen I. Conversely, overexpression of PAPSS2 promotes the MC3T3-E1 to differentiate into osteoblast and mineralization. Moreover, compared to that in the control cells, the mRNA level and protein expression of phosphorylated Smad 2/3, which is a key transcriptional factor in the Smad osteoblast differentiation pathway, showed significant decreases in PAPSS2-silenced cells and increases in PAPSS2-overexpression cells. These results suggest that PAPSS2 might regulate osteoblast ALP activity and cell mineralization, probably through Smads signal pathways

The Proosteogenic and Proangiogenic Effects of Small Extracellular Vesicles Derived from Bone Marrow Mesenchymal Stem Cells Are Attenuated in Steroid-Induced Osteonecrosis of the Femoral Head

Small extracellular vesicles (sEVs) derived from bone marrow mesenchymal stem cells (BMMSCs) from individuals with steroid-induced osteonecrosis of the femoral head (ONFH) have not been studied. The objective of the present study was to compare the proosteogenic and proangiogenic effects of sEVs derived from BMMSCs from rats with steroid-induced ONFH (oBMMSCs-sEVs) and sEVs derived from BMMSCs from normal rats (nBMMSCs-sEVs). BMMSCs were isolated from steroid-induced ONFH rats and healthy rats. sEVs were isolated and characterized by Western blotting analysis of exosomal surface biomarkers and by transmission electron microscopy. The impacts of nBMMSCs-sEVs and oBMMSCs-sEVs on the proliferation and osteogenic differentiation of BMMSCs were determined via cell proliferation assay, alizarin red staining, and alkaline phosphatase activity assay. Enzyme-linked immunosorbent assay and tube formation assay were conducted to investigate the effect of nBMMSCs-sEVs and oBMMSCs-sEVs on the angiogenic potential of human umbilical vein endothelial cells (HUVECs). The expression of relevant genes was detected by quantitative real-time polymerase chain reaction analysis, and the expression of β-catenin was detected by immunofluorescence. Both nBMMSCs-sEVs and oBMMSCs-sEVs promoted proliferation, osteogenic differentiation, and β-catenin expression of BMMSCs and enhanced angiogenesis of HUVECs. However, compared with nBMMSCs-sEVs, oBMMSCs-sEVs exhibited attenuated effects. Our findings indicated that the proosteogenic and proangiogenic effects of sEVs were partially attenuated in steroid-induced ONFH. Therefore, this study might offer guidance for the selection of source cells for sEV therapy in the future

Outcome at the end of follow-up.

<p>THA: total hip arthroplasty; BA: Bipolar hemiarthroplasty; The total modified Harris Hip score (HHS) was converted to a maximum of 100 points; HHS, VAS: students t-test; mortality: chi-squared test; revision operation, dislocation: Fisher’s exact test.</p