Scientific and industrial status of tissue engineering

Tissue engineering is a newly emerging field targeting many unresolved health problems. So far, the achievements of this technology in the production of different tissue engineered substitutes were promising. This review is intended to describe, briefly and in a simple language, what tissueengineering is, what the achievements of this technology are, what the market volume for its products is, what knowledge is needed for practice of this science, how different countries approached this field, and the effects of tissue engineering on national development. This report is primarily written to raise awareness of health authorities and policy makers in developing countries to this technology and help them to approach this multidisciplinary field in a proper way

Scientific and industrial status of tissue engineering

Tissue engineering is a newly emerging field targeting many unresolved health problems. So far, the achievements of this technology in the production of different tissue engineered substitutes were promising. This review is intended to describe, briefly and in a simple language, what tissue engineering is, what the achievements of this technology are, what the market volume for its products is, what knowledge is needed for practice of this science, how different countries approached this field, and the effects of tissue engineering on national development. This report is primarily written to raise awareness of health authorities and policy makers in developing countries to this technology and help them to approach this multidisciplinary field in a proper way. © 2007 Academic Journals

Effects of growth factors on the differentiation of murine ESC into type II pneumocytes

We have previously shown that embryonic stem cells (ESC) can be directed to differentiate into alveolar type II cells by provision of a serum-free medium designed for in vitro maintenance of mature alveolar epithelial cells (small airway growth medium: SAGM), although the target cell yield was low. SAGM comprises a basal serum-free medium (SABM) plus a series of defined supplements. In order to try increase the proportion of pneumocytes in differentiated cultures, we aimed in this study to determine the effects on murine ESC of each of the individual growth factors in SAGM. In accordance with our previous reports, expression of surfactant protein C (SPC) and its mRNA was used to monitor differentiation of type II pneumocytes. Surprisingly, we found that addition of each factor separately to SABM decreased the expression of SPC mRNA when compared with the effect of SABM alone. Thus, it seems that the observed enhancement by SAGM of pneumocyte differentiation from murine ESC can, in fact, be attributed to the provision of a serum-free environment. © Mary Ann Liebert, Inc. 2007

Tuning the conformation and mechanical properties of silk fibroin hydrogels

Mechanical properties of biomaterials play an important role in their biological performance. Among the most important parameters in designing of biomaterials, their structure and conformation strongly affect their mechanical properties as well as cell adhesion, proliferation, and differentiation. Silk fibroin (SF), extracted from Bombyx mori cocoons, has attracted a lot of scientific interest in the past years as a natural biomaterial due to its exceptional host tissues response, appropriate mechanical properties, tunable degradation, simple processing method and low cost. The formation of β-sheets in the structure of SF enhances its mechanical properties. In recent years, several studies have focused on tuning the mechanical properties of SF for biomedical applications by inducing the formation of β-sheets. Some treatment methods have been introduced to alter SF structure and improve its mechanical properties. Chemical, physical and enzymatic crosslinking, water and alcoholic treatments and irradiations have been recommended as methods to inducing β-sheets conformation in SF structure. Several studies have developed these methods by adding suitable components and changing the concentration, temperature, humidity, pH, and various other parameters. In this review, we focus on the treatment methods, which result in the conformational transition of SF and tuning its mechanical properties. © 2020 The Author

Characterization of lung fibroblasts more than two decades after mustard gas exposure

Purpose: In patients with short-term exposure to the sulfur mustard gas, the delayed cellular effects on lungs have not been well understood yet. The lung pathology shows a dominant feature consistent with obliterative bronchiolitis, in which fibroblasts play a central role. This study aims to characterize alterations to lung fibroblasts, at the cellular level, in patients with delayed respiratory complications after short-term exposure to the sulfur mustard gas. Methods: Fibroblasts were isolated from the transbronchial biopsies of patients with documented history of exposure to single high-dose sulfur mustard during 1985-7 and compared with the fibroblasts of control subjects. Results: Compared with controls, patients' fibroblasts were thinner and shorter, and showed a higher population doubling level, migration capacity and number of filopodia. Sulfur mustard decreased the in vitro viability of fibroblasts and increased their sensitivity to induction of apoptosis, but did not change the rate of spontaneous apoptosis. In addition, higher expression of alpha smooth muscle actin showed that the lung's microenvironment in these patients is permissive for myofibroblastic differentiation. Conclusions: These findings suggest that in patients under the study, the delayed pulmonary complications of sulfur mustard should be considered as a unique pathology, which might need a specific management by manipulation of cellular components. © 2015 Pirzad Jahromi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Matrix metalloproteinase-9 and paraoxonase 1 Q/R192 gene polymorphisms and the risk of coronary artery stenosis in Iranian subjects

Purpose: To investigate the association of matrix metalloproteinase-9 (MMP-9) and paraoxonase 1 (PON1) 192 polymorphisms with susceptibility to coronary artery stenosis (CAS) and the number of diseased vessels in patients with CAS. Methods: The study population comprised 302 unrelated Iranian individuals, including 145 patients with CAS and 157 control subjects. Genotypes for MMP-9 and PON1 192 polymorphisms were determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). Results: In our study, distributions of the TT genotype of MMP-9 and the RR genotype of PON1 192 were significantly higher in patients compared with healthy control subjects (P0.05). Conclusions: The observation indicates that the polymorphisms in the MMP-9 and PON1 192 genes potentially play a role in the manifestation of coronary atherosclerosis but does not have any effect on the number of diseased vessels in Iran. © 2010 Wiley-Liss, Inc

PLGA/TiO2 nanocomposite scaffolds for biomedical applications: Fabrication, photocatalytic, and antibacterial properties

Introduction: Porous 3D scaffolds synthesized using biocompatible and biodegradable materials could provide suitable microenvironment and mechanical support for optimal cell growth and function. The effect of the scaffold porosity on the mechanical properties, as well as the TiO2 nanoparticles addition on the bioactivity, antimicrobial, photocatalytic, and cytotoxicity properties of scaffolds were investigated. Methods: In the present study, porous scaffolds consisting poly (lactide-co-glycolide) (PLGA) containing TiO2 nanoparticles were fabricated via air-liquid foaming technique, which is a novel method and has more advantages due to not using additives for nucleation compared to former ways. Results: Adjustment of the foaming process parameters was demonstrated to allow for textural control of the resulting scaffolds and their pore size tuning in the range of 200-600 μm. Mechanical properties of the scaffolds, in particular, their compressive strength, revealed an inverse relationship with the pore size, and varied in the range of 0.97-0.75 MPa. The scaffold with the pore size 270 μm, compressive strength 0.97 MPa, and porosity level 90, was chosen as the optimum case for the bone tissue engineering (BTE) application. Furthermore, 99 antibacterial effect of the PLGA/10 wt. TiO2 nanocomposite scaffolds against the strain was achieved using Escherichia coli. Besides, no negative effect of the new method was observed on the bioactivity behavior and apatite forming ability of scaffolds in the simulated body fluid (SBF). This nanocomposite also displayed a good cytocompatibility when assayed with MG 63 cells. Lastly, the nanocomposite scaffolds revealed the capability to degrade methylene blue (MB) dye by nearly 90 under the UV irradiation for 3 hours. Conclusion: Based on the results, nanocomposite new scaffolds are proposed as a promising candidate for the BTE applications as a replacement for the previous ones. © 2020 Tabriz University of Medical Sciences. All rights reserved

Epigallocatechin gallate/layered double hydroxide nanohybrids: Preparation, characterization, and in vitro anti-tumor study

In recent years, nanotechnology in merging with biotechnology has been employed in the area of cancer management to overcome the challenges of chemopreventive strategies in order to gain promising results. Since most biological processes occur in nano scale, nanoparticles can act as carriers of certain drugs or agents to deliver it to specific cells or targets. In this study, we intercalated Epigallocatechin-3-Gallate (EGCG), the most abundant polyphenol in green tea, into Ca/Al-NO3 Layered double hydroxide (LDH) nanoparticles, and evaluated its efficacy compared to EGCG alone on PC3 cell line. The EGCG loaded LDH nanohybrids were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM) and nanosizer analyses. The anticancer activity of the EGCG-loaded LDH was investigated in prostate cancer cell line (PC3) while the release behavior of EGCG from LDH was observed at pH 7.45 and 4.25. Besides enhancing of apoptotic activity of EGCG, the results showed that intercalation of EGCG into LDH can improve the anti-tumor activity of EGCG over 5-fold dose advantages in in-vitro system. Subsequently, the in-vitro release data showed that EGCG-loaded LDH had longer release duration compared to physical mixture, and the mechanism of diffusion through the particle was rate-limiting step. Acidic attack was responsible for faster release of EGCG molecules from LDH at pH of 4.25 compared to pH of 7.4. The results showed that Ca/Al-LDH nanoparticles could be considered as an effective inorganic host matrix for the delivery of EGCG to PC3 cells with controlled release properties. © 2015 Shafiei et al.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

A pure population of lung alveolar epithelial type II cells derived from human embryonic stem cells.

Alveolar epithelial type II (ATII) cells are small, cuboidal cells that constitute approximately 60% of the pulmonary alveolar epithelium. These cells are crucial for repair of the injured alveolus by differentiating into alveolar epithelial type I cells. ATII cells derived from human ES (hES) cells are a promising source of cells that could be used therapeutically to treat distal lung diseases. We have developed a reliable transfection and culture procedure, which facilitates, via genetic selection, the differentiation of hES cells into an essentially pure (\u3e99%) population of ATII cells (hES-ATII). Purity, as well as biological features and morphological characteristics of normal ATII cells, was demonstrated for the hES-ATII cells, including lamellar body formation, expression of surfactant proteins A, B, and C, alpha-1-antitrypsin, and the cystic fibrosis transmembrane conductance receptor, as well as the synthesis and secretion of complement proteins C3 and C5. Collectively, these data document the successful generation of a pure population of ATII cells derived from hES cells, providing a practical source of ATII cells to explore in disease models their potential in the regeneration and repair of the injured alveolus and in the therapeutic treatment of genetic diseases affecting the lung

The effect of intrathecal delivery of bone marrow stromal cells on hippocampal neurons in rat model of Alzheimer�s disease

Objective(s): Intracerebral injection of bone marrow stromal cells (BMSCs) is being investigated as a therapeutic tool to prevent Alzheimer's disease (AD). Our aim was to investigate the effects of BMSCs by intrathecal injection in AD rat model. Materials and Methods: BMSCs were obtained from the bone marrow of Wistar rat and transplanted into AD rat model via intrathecal injection. The rat model had received an injection of � amyloid into the hippocampus for histological and immunohistochemical studies. Results: Histological examination of the brains in transplanted rats compared to controls demonstrated the migration of BrdU-labeled BMSCs from the site of delivery, confirmed the differentiation of BMSCs transplanted cells into the cholinergic neurons, and increased number of healthy and decreased number of dark neurons. Conclusion: Our results showed that BMSCs intratechal administration could be a promising method for treatment of Alzheimer�s disease in rat model. © 2015, Iranian Journal of Basic Medical Sciences. All rights reserved