Repair of critical-sized bone defects with anti-miR-31-expressing bone marrow stromal stem cells and poly(glycerol sebacate) scaffolds

The repair of critical-sized defects (CSDs) is a significant challenge in bone tissue engineering. Combining the use of progenitor cells with gene therapy represents a promising approach for bone regeneration. MicroRNAs play important roles in most gene regulatory networks, regulate the endogenous expression of multiple growth factors and simultaneously modulate stem cell differentiation. Our previous study showed that knocking down miR-31 promotes the osteogenesis of bone marrow stromal stem cells (BMSCs). To investigate the therapeutic potential of cells engineered to express anti-miR-31 for CSD repair, lentiviral vectors encoding negative control, miR-31 precursor and anti-sense sequences were constructed and transduced into osteo-inductive BMSCs. The expression of osteogenic-specific genes, alkaline phosphatase activity and Alizarin Red S staining were investigated to evaluate the effects of miR-31 on the cell fate of BMSCs over a 3-week period. In addition, miR-31-modified BMSCs seeded on poly(glycerol sebacate) (PGS) scaffolds were used to repair 8 mm critical-sized calvarial defects in rats. The results showed that miR-31 suppression significantly increased the expression of osteogenic-specific genes in vitro at the mRNA and protein levels, and that robust new bone formation with high local bone mineral density was observed in the anti-miR groups in vivo. Moreover, the PGS scaffolds carrying anti-miR-31-expressing BMSCs exhibited good biocompatibility and a high regeneration rate (~60%) within in vivo bone defects. Our results suggest that miR-31 gene delivery affects the potential of BMSCs for osteogenic differentiation and bone regeneration and that PGS is a potential substrate for genetically modified, tissue-engineered bone in the repair of large bone defects.

Efficacy and safety of long-term tadalafil 5 mg once daily combined with sildenafil 50 mg as needed at the early stage of treatment for patients with erectile dysfunction

This study aimed to evaluate the efficacy and safety of long-term and low-dose tadalafil combined with sildenafil as needed at the early stage of treatment for erectile dysfunction (ED). We enrolled 180 patients with ED 1 : 1 to tadalafil 5 mg once daily or once-a-day tadalafil 5 mg combined with sildenafil 50 mg as needed. The efficacy measures included the 5-item version of the International Index of Erectile Function (IIEF-5) and the Sexual Encounter Profile (SEP). The safety was assessed by observing drug tolerability and adverse events. Total IIEF-5 scores of patients with severe ED in combined medication group were significantly higher than in tadalafil alone group. Question 2 scores of IIEF-5 of patients with moderate and severe ED in combined medication group were significantly higher than in tadalafil alone group. The significant improvement in question 3 scores of IIEF-5 existed only in patients with severe ED receiving combined medication. The percentage of 'yes' responses to SEP4, SEP5 and partner's SEP3 were improved significantly in combined medication group. There was no difference between two groups in the incidence of adverse events. Our results suggest that combined medication can better improve erectile function, especially for patients with severe ED.

Synthesis and photovoltaic properties of new donor–acceptor (D–A) copolymers based on benzo[1,2-b:3,4-b′:6,5-b′′] trithiophene donor and different acceptor units (P1 and P2)

A power conversion efficiency of about 5.26% has been achieved for the device based onP1:PC71BM.

195 EFFECTS OF GSK3 INHIBITOR ON THE PLURIPOTENCY MAINTENANCE OF BUFFALO EMBRYONIC STEM-CELL-LIKE CELLS

In this study, to explore the effects and mechanism of Wnt/β-catenin signalling pathway on the maintenance of pluripotency of buffalo embryonic stem-cell-like cells (buffalo ESC-like cells), the GSK3 inhibitors BIO and CHIR99021 were added throughout the experiment – i.e. from buffalo inner cell mass (ICM) culture to ESC-like line generation. The buffalo ICM were respectively cultured in the medium containing 0.5 μg mL–1 BIO and 5 mmol L–1 CHIR99021. The percentage of ICMs attachment and primary colony formation were observed, and found that there was no significant difference in the ICMs attachment rate among of the BIO, CHIR99021, and the control groups (91.18% and 92.98% v. 94.59%; P > 0.05). Treating ICMs with CHIR99021 resulted in more primary colony formation rate compared with the control group (77.71% v. 55.41%; P < 0.05). The proliferation rate of primary colonies of buffalo ESC-like cells was detected by bromodeoxyuridine immunofluorescence techniques. The results show that the proliferation rate of primary colonies in the group of buffalo ESC-like cells treated with CHIR99021 was significantly higher than that of the control group on Day 1, Day 3, Day 4, and Day 5 (P < 0.05), and it was also evidently higher than that of control group only on Day 1 (P < 0.05) in the group of BIO, but there was no significant difference in other days (P > 0.05). The mRNA expression level of proliferation marker PCNA of ESC-like cells was significantly up-regulated in both CHIR99021 and BIO treatment groups (P < 0.05), however, treating buffalo ESC-like cells with CHIR99021 significantly up-regulated the expression of pluripotent gene Oct4 and Sox2 (P < 0.05), but had no effect on pluripotent gene Nanog expression (P > 0.05). Oct4 expression was significantly increased (P < 0.05), and the expression of Sox2 and Nanog were significantly decreased (P < 0.05) in the group of BIO treatment. Furthermore, the relative protein level of β-catenin (the downstream effector of Wnt/β-catenin signalling pathway) and the mRNA expression level of c-Myc (the downstream target gene of Wnt/β-catenin signalling pathway) were significantly increased when buffalo ESC-like cells respectively treated with CHIR99021 and BIO (P < 0.05). In conclusion, treating buffalo ESC-like cells with GSK3 inhibitors CHIR99021 can promote proliferation of buffalo ESC-like cells, maintain their undifferentiated state, and up-regulate the expression levels of β-Catenin and c-Myc in buffalo ESC-like cells. These results indicate that Wnt/β-catenin signalling pathway plays an important role in regulation of self-renewal of buffalo ESC-like cells. This work was funded by the China High Technology Development Program (2011AA100607), China Natural Science Foundation (31072033), and Guangxi Science Foundation (2012GXNSFFA060004).

ALDH1 is an independent prognostic factor for patients with stages II-III rectal cancer after receiving radiochemotherapy

Background:

About one in five patients with locally advanced rectal cancer (RC) suffers recurrence or distant metastasis after neoadjuvant therapy. We investigated how cancer stem cell markers change after neoadjuvant therapy and how these markers relate to recurrence.

Methods:

Pretreatment biopsies and postoperative specimens were taken from 64 patients with locally advanced rectal adenocarcinoma who received preoperative radiochemotherapy (RCT) between sampling. Samples were tested immunohistochemically for CD44, LGR5, ALDH1 and CD166; scores were dichotomised as high or low. The median follow-up period was 36 months.

Results:

High expression of CD44, LGR5, ALDH and CD166 was found in 38%, 5%, 48% and 10%, respectively, before RCT and 86%, 33%, 71% and 52%, respectively, after RCT. CD44 (P=0.001), LGR5 (P=0.049) and CD166 (P=0.003) were significantly upregulated after RCT. Whereas no recurrence was seen during the follow-up in the low ALDH group, 40% of the high ALDH group suffered recurrence. In multivariate COX analysis, postoperative ALDH1 independently predicted poor prognosis in patients with RC who received RCT (P=0.0095).

Conclusion:

Preoperative RCT upregulates expression of stem cell markers in patients with RC. High post-treatment ALDH1 expression predicts poor prognosis for these patients after neoadjuvant therapy.

Preparation and Characterization of Bamboo Fibers Coated with Titanium Urushiol and its Composite Materials with Polypropylene

Bamboo fibers (BFs) coated with titanium urushiol (BFTiU) was prepared by in situ reaction. Effects of activation time, urushiol concentration, reaction time and butyl titanate concentration etc on the coating ratio of BFTiU were investigated. On the other hand, the BFTiU was characterized by FTIR measurements, scanning electron microscope, thermo gravimetric analysis and differential scanning calorimetry. The results showed that titanium urushiol compound was coated on the BFs by coordination reaction and the coating ratio of BFTiU reached 35% at the optimal preparation condition. It also could be found that BFTiU possessed better heat resistant properties than BFs. Due to titanium urushiol coated on BFs, the elongation at break, the maximum deflection and the bending strength of BFTiU/PP composites were 33%, 30 % and 10% higher than those of BP/PP composites respectively. Particularly, the tensile strength of BFTiU/PP composites was better than that of BP/PP composites at the presence of 70% BFTiU.

Long-term self-renewal of human pluripotent stem cells on peptide-decorated poly(OEGMA-co-HEMA) brushes under fully defined conditions

Realization of the full potential of human induced pluripotent stem cells (hiPSC) in clinical applications requires the development of well-defined culture conditions for their long-term growth and directed differentiation. This paper describes a novel fully defined synthetic peptide-decorated substrate that supports self-renewal of hiPSC in commercially available xeno-free, chemically defined medium. The Au surface was deposited by a poly(OEGMA-co-HEMA) film, using the surface-initiated polymerization method (SIP) with the further step of carboxylation. The hiPSC generated from umbilical cord mesenchymal cells were successfully cultured for 10 passages on the peptide-tethered poly(OEGMA-co-HEMA) brushes for the first time. Cells maintained their characteristic morphology, proliferation and expressed high levels of markers of pluripotency, similar to the cells cultured on Matrigel™. Moreover, the cell adhesion could be tuned by the pattern and peptide concentration on the substrate. This well-defined, xeno-free and safe substrate, which supports long-term proliferation and self-renewal of hiPSC, will not only help to accelerate the translational perspectives of hiPSC, but also provide a platform to elucidate the underlying molecular mechanisms that regulate stem cell proliferation and differentiation via SIP technology.

Hedgehog signaling induces osteosarcoma development through Yap1 and H19 overexpression

Osteosarcoma is one of the most common bone tumors. However, the genetic basis for its pathogenesis remains elusive. Here, we investigated the roles of Hedgehog (Hh) signaling in osteosarcoma development. Genetically-engineered mice with ubiquitous upregulated Hh signaling specifically in mature osteoblasts develop focal bone overgrowth, which greatly resembles the early stage of osteosarcoma. However, these mice die within three months, which prohibits further analysis of tumor progression. We therefore generated a mouse model with partial upregulated Hh signaling in mature osteoblasts and crossed it into a p53 heterozygous background to potentiate tumor development. We found that these mutant mice developed malignant osteosarcoma with high penetrance. Isolated primary tumor cells were mainly osteoblastic and highly proliferative with many characteristics of human osteosarcomas. Allograft transplantation into immunocompromised mice displayed high tumorigenic potential. More importantly, both human and mouse tumor tissues express high level of yes-associated protein 1 (Yap1), a potent oncogene that is amplified in various cancers. We show that inhibition of Hh signaling reduces Yap1 expression and knockdown of Yap1 significantly inhibits tumor progression. Moreover, long non-coding RNA H19 is aberrantly expressed and induced by upregulated Hh signaling and Yap1 overexpression. Our results demonstrate that aberrant Hh signaling in mature osteoblasts is responsible for the pathogenesis of osteoblastic osteosarcoma through Yap1 and H19 overexpression.

Quercetin protects rat hepatocytes from oxidative damage induced by ethanol and iron by maintaining intercellular liable iron pool

Accumulating evidence has shown that ethanol-induced iron overload plays a crucial role in the development and progression of alcoholic liver disease. We designed the present study to investigate the potential protective effect of quercetin, a naturally occurring iron-chelating antioxidant on alcoholic iron overload and oxidative stress. Ethanol-incubated (100 mmol/L) rat primary hepatocytes were co-treated by quercetin (100 µmol/L) and different dose of ferric nitrilotriacetate (Fe-NTA) for 24 h. When the hepatic enzyme releases in the culture medium, redox status of hepatocytes and the intercellular labile iron pool (LIP) level were assayed. Our data showed that Fe-NTA dose dependently induced cellular leakage of aspartate transaminase and lactate dehydrogenase, glutathione depletion, superoxide dismutase inactivation, and overproduction of malondialdehyde) and reactive oxygen species (ROS) of intact and especially ethanol-incubated hepatocytes. The oxidative damage resulted from ethanol, Fe-NTA, and especially their combined treatment was substantially alleviated by quercetin, accompanying the corresponding normalization of intercellular LIP level. Iron in excess, thus, may aggravate ethanol hepatotoxicity through Fenton-active LIP, and quercetin attenuated ethanol-induced iron and oxidative stress. To maintain intercellular LIP contributes to the hepatoprotective effect of quercetin besides its direct ROS-quenching activity.

Decreased expression of p38 MAPK mediates protective effects of hydrogen sulfide on hepatic fibrosis

AIM

To investigate the in vitro and in vivo effects of hydrogen sulfide (H2S) on activated hepatic stellate cells (HSCs) and carbon tetrachloride (CCl4)-induced hepatic fibrosis rats. To explore the in vitro and in vivo expression of Phospho-p38, Phospho-Akt and NF-kB in HSCs treated with H2S.

MATERIALS AND METHODS

HSC-T6 cells were incubated and activated with 500 µg/L ferric nitrilotriacetate (Fe-NTA), and then were incubated with NaHS, an H2S-releasing molecule for 6, 12, 24 and 48 h. MTT assay was performed to detect cell viability. Propidium iodide (PI) staining was used to determine cell cycle by flow cytometry. Apoptosis was detected with Annexin-V FITC (fluorescein isothiocyanate) and PI (propidium iodide) double staining. Western blotting was performed to detect protein expressions of Phospho-p38, Phospho-Akt and NF-kB. Hepatic fibrosis model was established by intraperitoneal injection of CCl4 in male Wistar rats, and rats were randomly divided into three groups, including healthy control, rats treated with CCl4 + saline, and rats treated with CCl4 + NaHS. Immunohistochemistry analysis was performed to measure protein expression of Phospho-p38 and Phospho-Akt in rat hepatic samples.

RESULTS

NaHS inhibited the proliferation of Fe-NTA (nitrilotriacetic acid)-induced HSC-T6 cells in a dose-dependent way at 6, 12, 24 and 48 h. NaHS (500 µmol/L) induced G1 phase cell cycle arrest and promoted survival in Fe-NTA-induced HSC-T6 cells. NaHS decreased Phospho-p38 and increased Phospho-Akt expressions in Fe-NTA-induced HSC-T6 cells and CCl4-induced liver fibrosis rats.

CONCLUSIONS

Exogenous H2S inhibits activated HSC-T6 cells and induces cell cycle arrest and apoptosis. Decreased Phospho-p38 and increased Phospho-Akt expressions may mediate the anti-fibrosis effect by exogenous H2S.

Influence of indoor formaldehyde pollution on respiratory system health in the urban area of Shenyang, China

BACKGROUND

The decoration of interior spaces can lead to dangerous levels of indoor formaldehyde pollution. Exposure to indoor air pollution may be responsible for nearly 2 million deaths per year in developing countries.

OBJECTIVES

To assess the prevalence of indoor formaldehyde pollution caused by decoration and resultant respiratory system symptoms exhibited in exposed adults and children, due to indoor formaldehyde pollution caused by decoration.

METHODS

Survey sites were chosen and indoor formaldehyde concentrations determined according to the standard of formaldehyde in GB50325-2001. Logistic regression models were used to derive odds ratios (ORs) and 95% confidence intervals (95% CIs) after adjusting for potential confounders for this survey.

RESULTS

Formaldehyde concentration was above the standard in 64% of Shenyang City. Some adults surveyed complained of common respiratory system disorders, including coughing (11.8%), nasal irritation (39.2%), Heterosmia (14.51%), and throat irritation (25.27%); 12% of children suffered from asthma. The analysis identified formaldehyde pollution and ventilation frequency as risk factors for respiratory system disorders in both adults (OR=2.603, [95% CI: 1.770-3.828], OR=1.604, [95% CI: 1.146-2.244], respectively) and children (OR=4.250, [2.064-8.753], OR=1.831, [1.006-3.333], respectively).

CONCLUSION

The prevalence of common respiratory system disorders was related both to formaldehyde pollution and insufficient ventilation after decorating.

Pharmacological reduction of NEFA restores the efficacy of incretin-based therapies through GLP-1 receptor signalling in the beta cell in mouse models of diabetes

AIMS/HYPOTHESIS

Type 2 diabetes mellitus is associated with reduced incretin effects. Although previous studies have shown that hyperglycaemia contributes to impaired incretin responses in beta cells, it is largely unknown how hyperlipidaemia, another feature of type 2 diabetes, contributes to impaired glucagon-like peptide 1 (GLP-1) response. Here, we investigated the effects of NEFA on incretin receptor signalling and examined the glucose-lowering efficacy of incretin-based drugs in combination with the lipid-lowering agent bezafibrate.

METHODS

We used db/db mice to examine the in vivo efficacy of the treatment. Beta cell lines and mouse islets were used to examine GLP-1 and glucose-dependent insulinotropic peptide receptor signalling.

RESULTS

Palmitate treatment decreased Glp1r expression in rodent insulinoma cell lines and isolated islets. This was associated with impairment of the following: GLP-1-stimulated cAMP production, phosphorylation of cAMP-responsive elements binding protein (CREB) and insulin secretion. In insulinoma cell lines, the expression of exogenous Glp1r restored cAMP production and the phosphorylation of CREB. Treatment with bezafibrate in combination with des-fluoro-sitagliptin or exendin-4 led to more robust glycaemic control, associated with improved islet morphology and beta cell mass in db/db mice.

CONCLUSIONS/INTERPRETATION

Elevated NEFA contributes to impaired responsiveness to GLP-1, partially through downregulation of GLP-1 receptor signalling. Improvements in lipid control in mouse models of obesity and diabetes increase the efficacy of incretin-based therapy.