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Hadi Hajiali1, Shapour Shahgasempour1, M Reza Naimi-Jamal2, Habibullah Peirovi11Nanomedicine and Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences; 2Department of Chemistry, Iran University of Science and Technology, Tehran, IranBackground and methods: In this study, gelatin was blended with polyglycolic acid (PGA) at different ratios (0, 10, 30, and 50 wt%) and electrospun. The morphology and structure of the scaffolds were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and differential scanning calorimetry. The mechanical properties were also measured by the tensile test. Furthermore, for biocompatibility assessment, human umbilical vein endothelial cells and human umbilical artery smooth muscle cells were cultured on these scaffolds, and cell attachment and viability were evaluated.Results: PGA with 10 wt% gelatin enhanced the endothelial cells whilst PGA with 30 wt% gelatin increased smooth muscle cell adhesion, penetration, and viability compared with the other scaffold blends. Additionally, with the increase in gelatin content, the mechanical properties of the scaffolds were improved due to interaction between PGA and gelatin, as revealed by Fourier transform infrared spectroscopy and differential scanning calorimetry.Conclusion: Incorporation of gelatin improves the biological and mechanical properties of PGA, making promising scaffolds for vascular tissue engineering.Keywords: polyglycolic acid, gelatin, nanofiber, vascular tissue engineering, biocompatible scaffold

Background and Objectives: Recently, interest has increased in the potential employment of embryonic stem cells for the treatment of Parkinson's disease, which has been considered as an alternative therapeutic strategy. Due to their pluripotent differentiation potential, the finding that they do not induce carcinoma and the fact that they do not raise the ethical concerns connected with human embryonic stem cells, human amniotic epithelial cells are considered to be a very promising cell source. The aim of this study was to investigate the effects of FGF8 and Shh on the expression of dopaminergic markers from human amniotic epithelial cells.Methods: In this study, we examined the differentiation of dopaminergic neurons in vitro from AECs using the expression of several markers including TH, DAT and DβH. For dopaminergic differentiation, sonic hedgehog (Shh) and FGF8 were added to cultures and the cultures were allowed to differentiate for 21 days. Analysis of AECs derived dopaminergic neurons was performed at the TH, DAT, β-tubulin III and DβH expression levels by immunocitochemistry. The significance of the data was tested by Student's t-test (between two groups) and one-way analysis of variance (ANOVA) followed by Tukey post-test. (p

Liver transplantation program has been launched at Organ Transplant Center of Taleghani Hospital, Shahid Beheshti University of Medical Sciences, Tehran, since January 2009. Herein, we report on the results of 116 liver transplantations so far performed in this center. Complications occurred in 42 (36.2%; 95% CI: 27.4%-45.1%) of patients, mostly sepsis, post-operative hemorrhage and respiratory failure. 32 (27.6%) of recipients died after transplantation. [ABSTRACT FROM AUTHOR]

The study on the health effects of combined exposure to various contaminants has been recommended by many authors. The objective of the present study was to examine the effects of the co-exposure to hematite and amorphous silicon dioxide (A-SiO 2 ) nanoparticles on the human lung A 549 cell line. The A 549 cell line was exposed to 10, 50, 100, and 250 µg/ml concentrations of hematite and A-SiO 2 nanoparticles both independently and in combination. Their toxicity in both circumstances was investigated by MTT, intracellular reactive oxygen species, cell glutathione content, and mitochondrial membrane potential tests, and the type of interaction was investigated by statistical analysis using Statistical Package for Social Sciences (SPSS, v. 21). Results showed that the independent exposure to either hematite or A-SiO 2 compared with the control group produced more toxic effects on the A 549 cell line. The toxicity of combined exposure of the nanoparticles was lower compared with independent exposure, and antagonistic interactive effects were detected. The findings of this study could be useful in clarifying the present debate on the health effects of combined exposure of hematite and A-SiO 2 nanoparticles. Because of the complexities of combined exposures, further studies of this kind are recommended.

Introduction: Amorphous silicon dioxide (A-SiO2) is abundant in the Earth's crust, the A-SiO2 nano and microparticles are released into the air through industrial and manufacturing activities. Due to the limited available toxicological information, the objective of the present study was to evaluate the toxicity of different sizes of A-SiO2 particles on the A549 cell-lines in an in vitro study., Materials and Methods: The A-SiO2 particles in two categories of nano (10-100 nm) and micro (< 5um) were used in this study. The human lung A549 cell-line was exposed to either nano- or micro-sized A-SiO2 particles at 10, 50, 100, and 250 μg/ml, and the effects were investigated., Results: The cytotoxicity of A-SiO2 nano and microparticles in both 24- and 72-hour exposure times resulted in decreased cell survival, mitochondrial membrane potential, and increased ROS generation which was concentration-time dependent (P <0.05) but glutathione content was not affected in a time-dependent manner. Cytotoxicity of nanoparticles, contrary to the previous study, was not higher than microparticles in the comparable dose and exposure times., Conclusion: The rate of ROS generation in the A549 cell-line exposed to A-SiO2 nanoparticles was higher than microparticles. And at the same time, cell survival for exposed cells to A-SiO2 nano and microparticles were higher for nanoparticles in shorter exposure periods and was inversely concentration- and time-dependent. Further studies on exploring the effect of size and its possible toxic mechanism are recommended to achieve a more credible risk assessment.

Introduction: Magnetite as iron oxide is widely used in various industries, in the pharmaceutical industry in particular where it is used for its magnetic properties. The environmental and occupational exposure to airborne nanoparticles and microparticles of iron oxide compounds have been reported. Since authors have reported contradictory results, the objective of this study was to investigate the effect of particles' size in their toxicities., Methods: The human cell line A 549 was exposed with magnetite iron oxide in two size categories of micro (≥5 µm) and nano (<100 nm), with four concentrations of 10, 50, 100, and 250 µg/ml at two time periods of 24 and 72 h. The cell viability, reactive oxygen species (ROS), changes in mitochondrial membrane potential, and incidence of apoptosis were studied., Results: Nano and micro magnetite particles demonstrated diverse toxicity effects on the A 549 cell line at the 24- and 72-h exposure periods; however, the effects produced were time- and concentration-dependent. Nano magnetite particles produced greater cellular toxicities in forms of decreased viabilities at concentration exposures greater than 50 µg/ml ( p < 0.05), along with increased ROS ( p < 0.05), decreased cellular membrane potential ( p < 0.05), and reduced rate of apoptosis ( p < 0.05)., Discussion: The results of this study demonstrated that magnetite iron in nano-range sizes had a greater absorbability for the A 549 cell line compared to micro sizes, and at the same time, nanoparticles were more toxic than microparticles, demonstrating higher production of ROS and decreased viabilities. Considering the greater toxicity of nanoparticles of magnetite iron in this study, thorough precautionary control measures must be taken before they can be used in various industries.

The increasing trend of nanoparticle usage in science and technology has led to significant human exposure. Occupational exposure to iron oxides and silica dust has been reported in mining, manufacturing, construction, and pharmaceutical operations. The combined toxicological effects of nanoparticles and simultaneous exposure to other compounds have given rise to a new concern. Hence, the objective of this study was to investigate the toxicological effects of magnetite and polymorphous silicon dioxide nanoparticles in single and combined exposures. The polymorphous silicon dioxide nanoparticles were obtained from the milled quartz particles under 100 nm in diameter. The milled particles were purified through chloric and nitric acid wash processes. The toxic effects of the magnetite nanoparticles were investigated independently and in combination with quartz using the A 549 cell line for durations of 24 and 72 h, and using diverse concentrations of 10, 50, 100, and 250 μg/mL. MTT, ROS, mitochondrial membrane potential, and cell glutathione content assays were used to evaluate the amount of cell damage in this study. The statistical significance level in one-way ANOVA and independent t test was considered to be at the 5% confidence level. The size and purity of polymorphous silicon dioxide nanoparticles were measured by TEM and ICP-OES analysis, respectively. The particles' diameters were under 100 nm and demonstrated a purity of higher than 99%. The toxicity results of this study showed a dependency on concentration and exposure duration in reducing the cell viability, cellular glutathione content, and mitochondrial membrane potential, as well as increasing the ROS generation in single and combined exposures with magnetite and polymorphous silicon dioxide nanoparticles. The toxic effects of combined exposure to these nanoparticles were less than the single exposures, and statistically significant antagonistic interactions were detected. Combined exposure to polymorphous silicon dioxide and magnetite nanoparticles, in comparison with their single exposures, could affect health in an antagonistic manner. Since this study has been the first of its kind, further studies investigating the health effects of single and combined exposures to these compounds are needed to verify our findings. Generally, studies such as this one could contribute to the field of combined toxicity effects.

In theenvironment, co-exposure to short-multiwalled carbon nanotubes (S-MWCNTs) and polycyclic aromatic compounds (PAHs) has been reported. In the co-exposure condition, the adsorption of PAHs onto MWCNTs may reduce PAHs toxic effect. The objective of this study was to investigate the cytotoxicity of S-MWCNTs and benzo[a]pyrene (B[a]P) individually, and in combination in human lung cell lines (A549). The adsorption of B[a]P onto MWCNTs was measured spectrometrically. In vitro toxicity was assessed through cell viability, reactive oxygen species (ROS) generation, apoptosis, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) generation experiments. The S-MWCNTs demonstrated cytotoxicity through the generation of ROS, apoptosis, and 8-OHdG in A549 cells. Co-exposure to S-MWCNTs and B[a]P demonstrated a significant reduction in ROS generation and apoptosis compared with the sum of their separate toxic effects at the same concentrations. Decreasing the bioavailability of B[a]P by MWCNT interaction is the probable reason for the antagonistic effects of the co-exposure condition. The findings of this study will contribute to a better understanding of the health effects of co-exposures to air pollutants and could be a starting point for modifying future health risk assessments.

Co-exposure to carboxylic acid functionalized multi-walled carbon nanotubes (F-MWCNTs) and polycyclic aromatic hydrocarbons (PAHs) such as benzo a pyrene (BaP) in ambient air have been reported. Adsorption of BaP to F-MWCNTs can influence combined toxicity. Studying individual toxicity of F-MWCNTs and BaP might give unrealistic data. Limited information is available on the combined toxicity of F-MWCNTs and BaP in human cells. The objective of the present work is to evaluate the toxicity of F-MWCNTs and BaP individually and combined in human lung adenocarcinoma (A549 cells). The in vitro toxicity is evaluated through cell viability, the production of reactive oxygen species (ROS), apoptosis, and the production of 8-OHdG assays. Adsorption of BaP to F-MWCNTs was confirmed using a spectrophotometer. The results indicated that the F-MWCNTs and BaP reduce cell viability individually and produce ROS, apoptosis, and 8-OHdG in exposed cells. Stress oxidative is found to be a mechanism of cytotoxicity for both F-MWCNTs and BaP. Combined exposure to F-MWCNTs and BaP decreases cytotoxicity compared to individual exposure, but the difference is not statistically significant in all toxicity assays; hence, the two-factorial analysis indicated an additive toxic interaction. Adsorption of BaP to F-MWCNTs could mitigate the bioavailability and toxicity of BaP in biological systems. Considering the mixture toxicity of MWCNTs and BaP is required for risk assessment of ambient air contaminants.

Background: The aim of this study was to investigate the neurotoxic effects of Fe 3 O 4 magnetic- CurNPs on isolated schizophrenia mitochondria of rats as an in vivo model., Methods: We designed CMN loaded superparamagnetic iron oxide nanoparticles (SPIONs) (Fe 3 O 4 magnetic- CurNPs) to achieve an enhanced therapeutic effect. The physicochemical properties of Fe 3 O 4 magnetic- CurNPs were characterized using X-ray diffraction (XRD), and dynamic laser light scattering (DLS) and zeta potential. Further, to prove Fe 3 O 4 magnetic- CurNPs results in superior therapeutic effects, and also, the mitochondrial membrane potential collapse, mitochondrial complex II activity, reactive oxygen species generation, ATP level, cytochrome c release and histopathology of cerebellums were determined in brains of schizophrenic rats., Results: We showed that effective treatment with CMN reduced or prevented Fe 3 O 4 magnetic-induced oxidative stress and mitochondrial dysfunction in the rat brain probably, as well as mitochondrial complex II activity, MMP, and ATP level were remarkably reduced in the cerebellum mitochondria of treated group toward control (p < 0.05). Therewith, ROS generation, and cytochrome c release were notably (p < 0.05) increased in the cerebellum mitochondria of treated group compared with control group., Conclusion: Taken together, Fe 3 O 4 magnetic- CurNPs exhibits potent antineurotoxicity activity in cerebellums of schizophrenic rats. This approach can be extended to preclinical and clinical use and may have importance in schizophernia treatment in the future. To our knowledge this is the first report that provides the Fe 3 O 4 magnetic- CurNPs could enhance the neuroprotective effects of CMN in the Schizophrenia., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Placenta-derived amniotic epithelial cells (AECs), a great cell source for tissue engineering and stem cell therapy, are immunologically inert in their native state; however, immunological changes in these cells after culture and differentiation have challenged their applications. The aim of this study was to investigate the effect of 2D and 3D scaffolds on human lymphocyte antigens (HLA) expression by AECs. The effect of different preparation parameters including pre-freezing time and temperature was evaluated on 3D chitosan-gelatine scaffolds properties. Evaluation of MHC class I, HLA-DR and HLA-G expression in AECs after 7 d culture on 2D bed and 3D scaffold of chitosan-gelatine showed that culture of AECs on the 2D substrate up-regulated MHC class I and HLA-DR protein markers on AECs surface and down-regulated HLA-G protein. In contrast, 3D scaffold did not increase protein expression of MHC class I and HLA-DR. Moreover, HLA-G protein expression remained unchanged in 3D culture. These results confirm that 3D scaffold can remain AECs in their native immunological state and modification of physical properties of the scaffold is a key regulator of immunological markers at the gene and protein expression levels; a strategy which circumvents rejection challenge of amniotic stem cells to be translated into the clinic.

Human mesenchymal stem cells (hMSCs) are multipotent cells appropriate for a variety of tissue engineering and cell therapy applications. Mechanical properties of hMSCs during differentiation are associated with their particular metabolic activity and regulate cell function due to alternations in cytoskeleton and structural elements. The objective of this study is to evaluate elastic and viscoelastic properties of hMSCs during long term cultivation in control and transforming growth factor-β1 treatment groups using micropipette aspiration technique. The mean Young's modulus (E) of the control samples remained nearly unchanged during 6 days of cultivation, but that of the test samples showed an initial reduction compared to its relevant control sample after 2 days of treatment by biological growth factor, followed by a significant rise after 4 and 6 days. The viscoelastic creep tests showed that both instantaneous and equilibrium moduli significantly increased with the treatment time and reached to maximum values of 622.9 ± 114.2 and 144.3 ± 11.6 Pa at the sixth day, respectively, while increase in apparent viscosity was not statistically significant. Such change of mechanical properties of hMSCs during specific lineage commitment contributes to regenerative medicine as well as stem-cell-based therapy in which biophysical signals regulate stem cell fate.

Background Aims: Amniotic membrane (AM), the innermost layer of human placenta, is composed of a single layer of epithelial cells, a basement membrane and an avascular stroma. The AM has many functions and properties, among which angiogenic modulatory and immunoregulatory effects are applicable in cancer therapy. Because these functions belong to amniotic epithelial cells, in this study we compared the anti-cancer effect of amniotic epithelial cells and the whole AM., Methods: The effect of the AM and the amniotic epithelial cells on cancer cell apoptosis was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium assay, terminal deoxynucleotidyl transferase dUTP nick end labeling assay and immunocytochemistry. The effect of the AM on angiogenesis in conditions both with and without epithelial cells was also evaluated using rat aortic ring assay., Results: There was a decrease in cancer cell viability after adding either AM or amniotic epithelial cell supernatant to cancer cells. A significant increase in caspase-3 and caspase-8 expression in cancer cells treated with amniotic epithelial cell supernatant was observed. The recorded media also demonstrated the possible induction of apoptosis in cancer cells treated with the amniotic epithelial cell supernatant. In the aorta ring assay, the AM showed an anti-angiogenic effect in the presence of its epithelial cells; however, this effect was altered to initiate angiogenesis when amniotic epithelial cells were removed from the AM., Conclusions: These results suggest that amniotic epithelial cells, with their anti-angiogenic effect and induction of apoptosis, are candidates for cancer therapeutic agents in the near future., (Copyright © 2014 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Background: In recent years, some studies have tried to improve Phase Contrast Microscopy (PCM) for counting asbestos fibers. Due to the lack of a universally accepted alternative method, this study aimed to improve PCM for better counting of asbestos fibers., Materials and Methods: Confirmed asbestos standards were applied using a dust generator for sampling. Sampling from the dust generator was carried out according to the Occupational Safety and Health Administration (OSHA) ID-160 method and 95 samples with diverse densities were prepared to be counted using conventional and modern PCM. All samples were counted single blindly by a co-author of this study and the obtained data were analyzed by paired t-test, correlation coefficient and Bland-Altman analysis. Duplicate samples were prepared for qualitative analysis by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X ray., Results: Asbestos densities on filters were in the range of less than 100 to 600 fibers/mm(2). Statistically, significant differences were observed for the count density of the 95 samples counted by the two phase contrast microscopes (P<0.001). Nikon microscope demonstrated higher counts compared to conventional microscope and had a lower coefficient of variation. Samples were analyzed qualitatively using FT-IR and SEM, and the presence of asbestos fibers was confirmed., Conclusion: The improved PCM and FT-IR methods presented in this study demonstrated more precise and accurate determination of personal exposure to airborne asbestos fibers and subsequent risk assessment.

Amniotic membrane (AM), the innermost layer of the fetal membrane, is considered as a suitable candidate for cancer therapy. In order to develop the AM as a new cancer therapeutic approach, it is essential to understand the molecular mechanism of the AM anti-cancer properties. Previous studies demonstrated that anti-proliferative effects of the AM on tumor cells were associated with induction of cell cycle arrest. Moreover, it has been shown that unknown substances in the AM induce apoptosis in cancer cells and inhibit angiogenesis in tumors. In contrast to the effects of the AM, heat shock proteins (HSPs), in particular HSP90, play a crucial role in development of tumorgenesis. HSP90 inhibits apoptosis in cancer cells and enhances angiogenesis and cell cycle progression. Based on the opposite effects of the amniotic membrane ingredients and HSP90, we hypothesized here that possible mechanism of the AM anti-cancer effects is through inhibition of HSP90., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Amniotic epithelial cells are a promising source for stem cell-based therapy through their potential capacity to differentiate into the cell lineages of all three germ layers. Long-term preservation is necessary to have a ready-to-use source of stem cells, when required. Reduced differentiation capability, decrease of viability and use of fetal bovine serum (FBS) are three drawbacks of clinical application of cryopreserved stem cells. In this study, we used human amniotic fluid instead of animal serum, and evaluated viability and multipotency of amniotic epithelial cells after cryopreservation in suspension and compared with those cryopreserved on their natural scaffold (in situ cryopreservation). There was no significant difference in viability of the cells cryopreserved in amniotic fluid and FBS. Also, the same results were achieved for expression of pluripotency marker OCT-4 when FBS was replaced by amniotic fluid in the samples with the same cryoprotectant. The cells cryopreserved in presence of scaffold had a higher level of viability compared to the cells cryopreserved in suspension. Although, the number of the cells expressed OCT-4 significantly decreased within cryopreservation in suspension, no decrease in expression of OCT-4 was observed when the cells cryopreserved with their natural scaffold. Upon culturing of post-thawed cells in specific lineage differentiating mediums, the markers of neuronal, hepatic, cardiomyocytic and pancreatic were found in differentiated cells. These results show that replacement of FBS by amniotic fluid and in situ cryopreservation of amniotic epithelial cells is an effective approach to overcome limitations related to long-term preservation including differentiation during cryopreservation and decrease of viability., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Objective: Amniotic membrane, as a natural biomaterial, has many advantages, such as low immunogenicity, anti-inflammation, antifibrosis, and rich extracellular matrix components, which make it a promising source for vascular tissue engineering. This study assessed the feasibility of constructing a vein conduit from the amniotic membrane and implanting it in the external jugular vein of juvenile sheep., Methods: Human amniotic membrane was prepared using fresh human placenta. For construction of a tube such as a vein, the membrane was rolled around a tube and amniotic membrane-constructed conduits were interposed to the external jugular vein by end-to-end anastomosis. Grafts were assessed for patency at weeks 5 and 48 and explanted for evaluation with histologic and microscopic techniques., Results: At 5 weeks after implantation, the grafts were completely patent and displayed no signs of dilation. The internal surface was smooth and shiny, without any evidence of thrombus formation. After 48 weeks, grafts were still completely patent and displayed no signs of intimal thickening, dilation, or stenosis. No inflammation or fibrosis was evident. Histologic evaluation of the explanted grafts demonstrated a monolayer of endothelial cells. Scanning electron microscopy revealed a confluent layer of cells with normal endothelial cell morphology. A monolayer of cells positive for von Willebrand factor was detected in histology sections., Conclusions: The findings of this study confirm that the amniotic membrane can be a proper substitute for vascular tissue engineering., (Copyright © 2012 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.)

Background: Type 1 diabetes mellitus is one of the metabolic diseases that cause insulin-producing pancreatic ß cells be destroyed by immune system self-reactive T cells. Recent-ly, new treatment methods have been developed including use of the stem cells, ß islet cells transplantation and gene therapy by viral and non-viral gene constructs., Objectives: The aim of this project was preparing the non-viral vector containing the glucose inducible insulin gene and using it in the NIH3T3 cell line., Materials and Methods: Cloning was carried out by standard methods. Total RNA was extracted from pancreatic tissue, RNA was converted to cDNA using RT-PCR reaction and preproinsulin gene was amplified using specific primers. PNMTCH plasmid was extract-ed and digested by NotI, HindIII, and MTIIA and ChoRE genes were purified and cloned into pcDNA3.1 (-) plasmid and named pcDNAMTCh. Finally, the preproinsulin genes were cloned into pcDNA3.1 (-) plasmid and pcDNAMTChIns was built., Results: The cloned gene constructs were evaluated by restriction enzyme digestion and RT-PCR. The NIH3T3 cells were transfected by plasmid naked DNA containing preproinsu-lin gene and expression was confirmed by Reverse Transcriptase PCR and Western Blot-ting Techniques., Conclusions: Gel electrophoresis of PCR products confirmed that cloning was per-formed correctly. The expression of preproinsulin gene in recombinant plasmid in NI-H3T3 cell line was observed for the first time. The findings in this study can be the basis of further research on diabetes mellitus type 1 gene therapy on animals.

Amniotic epithelial cells (AECs) have been the subject of interest due to their stem cells characteristics. Pluripotency, lack of teratoma formation, low immunogenicity and no ethical issues make them an alternative source of stem cells for generation of dopaminergic neurons in vitro. AECs may differentiate into midbrain dopaminergic neurons in the presence of induction factors which trigger pathway naturally occurring in the mesencephalon during embryogenesis. In this study, we examined whether FGF8 and Sonic hedgehog (Shh) can induce AECs to express permanently midbrain dopaminergic neurons traits. We found that fresh isolated AECs temporarily expressed some neural markers which decreased 7 days after culture. Co-treatment of cells with FGF8 and Shh had synergistic effect on expression of TH, DAT, Pax2, Lmx1b and En1. Shh ceased differentiation in dopaminergic state and decreased DβH. HPLC analysis revealed that dopamine was released into the medium upon depolarization, indicating that functional dopaminergic neurons were present in the culture. These results demonstrate that AECs have capability to differentiate into dopaminergic neurons and can be a candidate for cell replacement therapy of Parkinson's disease., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Amniotic membrane (AM) has been used as a scaffold for the ex vivo expansion of different types of cells and a cell delivery matrix in regenerative medicine. Since the preservation procedures can influence the AM properties for experimental and clinical purposes, this study was established to investigate the feasibility of using the AM after different preservation methods to serve as substrates for endothelial cell expansion ex vivo. The effects of cryopreservation and lyophilization were evaluated on mechanical and histological characteristics of the AM, and the results were compared with the fresh AM. The ECM components of the basement membrane were well conserved in all groups. Although lyophilization resulted in more histological changes and lower level of physical variables including thickness, F(max), elongation at break and suture retention than the fresh and cryopreserved AM, endothelial cells grown on the lyophilized AM were better attached to the basement membrane. Cytotoxicity assay by MTT showed that the lyophilized AM is a compatible substrate for endothelial cells cultivation. The findings of this study suggest that the lyophilized AM is a suitable matrix for cultivation of endothelial cells due to this fact that lyophilization led to exposure of basement membrane of the AM., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Postoperative neurologic deficit due to spinal cord ischemia-reperfusion (I/R) injury is the most devastating complication following thoracoabdominal aortic aneurysm repairs. The protective potential for 17β-Estradiol has not been yet studied in such injury. In this study, ischemia induction for 18 min in male New Zealand White rabbits resulted in the highest percentage (80%) of biphasic paraplegic outcome assessed by Tarlov's score. Acute Estradiol pretreatment (1 mg/kg, i.p., 30 min before I/R induction) altered this outcome and significantly prevented the worsening pattern of neurologic deficits over 48 h of observation. Histopathologic and oxidative stress evaluations of lumbar spinal cords taken in delayed permanent paraplegic phase (48 h after ischemia induction), further confirmed protective efficacy of Estradiol in such context. In western blot analysis, the expression of cleaved caspase-3 and heat shock protein 70 declined in Estradiol pretreated group compared to ischemic control group. TUNEL assay also showed the efficacy of Estradiol to abate motor neuron apoptosis. Interestingly, Estradiol respectively increased and decreased the expression of Cyclooxygenase (COX)-1 and COX-2, to a significant extent. Estradiol, exerting its protection through affecting one or a combination of involved biochemical factors can constitute a potential candidate to protect against thoracoabdominal aortic aneurysm repairs induced spinal cord I/R injury.

Background and Methods: In this study, gelatin was blended with polyglycolic acid (PGA) at different ratios (0, 10, 30, and 50 wt%) and electrospun. The morphology and structure of the scaffolds were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and differential scanning calorimetry. The mechanical properties were also measured by the tensile test. Furthermore, for biocompatibility assessment, human umbilical vein endothelial cells and human umbilical artery smooth muscle cells were cultured on these scaffolds, and cell attachment and viability were evaluated., Results: PGA with 10 wt% gelatin enhanced the endothelial cells whilst PGA with 30 wt% gelatin increased smooth muscle cell adhesion, penetration, and viability compared with the other scaffold blends. Additionally, with the increase in gelatin content, the mechanical properties of the scaffolds were improved due to interaction between PGA and gelatin, as revealed by Fourier transform infrared spectroscopy and differential scanning calorimetry., Conclusion: Incorporation of gelatin improves the biological and mechanical properties of PGA, making promising scaffolds for vascular tissue engineering.

The differentiation of neural cells from embryonic stem cells is influenced by several growth factors. Amniotic epithelial cells (AECs) share many of the same characteristics as embryonic stem cells, and therefore those factors may similarly affect the derivation of neural cells from AECs. In this study, we examined the differentiation of neural cells in vitro from AECs following AECs treatment with retinoic acid (RA), basic fibroblast growth factor (bFGF) as well as investigation of bFGF withdrawal on neuronal differentiation. We also studied whether blocking bone morphogenetic protein (BMP) signaling using its antagonist, noggin, affects the derivation of neuronal cells from AECs. The effects of serum on the rate of neural markers expression were also examined. Analysis of AECs derived neurons was performed at some neural markers expression level by immunocytochemistry. All cultures treated with noggin showed the higher levels of neural markers expression than noggin free cultures. Combined treatment with bFGF and RA showed the highest level of neural markers in all treatment groups with or without noggin. bFGF withdrawal did not promote expression of neural markers, while its maintenance increased the expression of these markers. Serum-free condition decreased the viability of cells but increased the rate of neural markers expression. These results show the capability of AECs to express neural cell markers and this ability is affected by some factors including serum, noggin, bFGF and RA.

An important component of tissue engineering (TE) is the supporting matrix upon which cells and tissues grow, also known as the scaffold. Scaffolds must easily integrate with host tissue and provide an excellent environment for cell growth and differentiation. Most scaffold materials are naturally derived from mammalian tissues. The amniotic membrane (AM) is considered an important potential source for scaffolding material. The AM represents the innermost layer of the placenta and is composed of a single epithelial layer, a thick basement membrane and an avascular stroma. The special structure and biological viability of the AM allows it to be an ideal candidate for creating scaffolds used in TE. Epithelial cells derived from the AM have the advantages of stem cells, yet are a more suitable source of cells for TE than stem cells. The extracellular matrix components of the basement membrane of the AM create an almost native scaffold for cell seeding in TE. In addition, the AM has other biological properties important for TE, including anti-inflammatory, anti-microbial, anti-fibrosis, anti-scarring, as well as reasonable mechanical property and low immunogenicity. In this review, the various properties of the AM are discussed in light of their potential use for TE.

Background: Silicone implants are being used increasingly worldwide, especially in breast augmentation procedures. The most common morbidity observed is capsular contracture, which occurs in 15 percent of cases. To overcome this problem, the authors have developed a novel nanocomposite based on polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane (POSS-PCU) for use as tissue implants., Methods: These polymers were implanted in six healthy sheep (n = 6) for 36 months and a siloxane served as the positive control. After explantation, these polymers were extracted, as was the surrounding capsule, if any. Attenuated total reflectance Fourier transform infrared spectroscopy analysis was performed to look for signs of surface degradation on the polymers and histopathologic and electron microscopic examinations were performed to study the interaction between the biomaterial and the host environment in greater detail., Results: After implantation, the authors observed minimal inflammation of the nanocomposite within the sheep model as compared with the siloxane control. Contact angle measurements and fibrinogen enzyme-linked immunosorbent assay tests were then conducted on the POSS-PCU nanocomposite to determine the reason for this behavior. The increased fibrinogen adsorption on POSS-PCU, its amphilicity, and large contact-angle hysteresis indicated that POSS-PCU inhibits inflammation by adsorbing and inactivating fibrinogen on its surface. In complete contrast, the control siloxane in the same setting demonstrated very significant inflammation and degradation, resulting in capsular formation. Naturally, there was no evidence of degradation of the nanocomposite compared with the siloxane control., Conclusions: POSS-PCU nanocomposites have enhanced interfacial biocompatibility and better biological stability as compared with conventional silicone biomaterials, thus making them safer as tissue implants.