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TGF-b downregulation by RNAi technique in ex vivo-expanded HSCs on 3D DBM scaffold 
Hashemi Zs, Forouzandeh Moghadam M, Soleimani M, Hafizi M, Amirizadeh N,
Volume 70, Issue 2 (5-2012)
Abstract

Background: Bone Marrow Transplantations (BMT) are limited by low CD34+ cell counts in umbilical cord blood (UCB) and these cells need to be expanded for success in such procedures. To achieve this goal, ex vivo expansion of hematopoietic stem cells (HSCs) by enhancing their self-renewal activity on demineralized bone matrix (DBM) scaffold coated with mesenchymal progenitor cells (MPCs) and unrestricted somatic stem cells (USSCs) was recommended. TGF-b pathway is a key inhibitory factor for HSCs self-renewal. In this study ex vivo expansion and downregulation of TGF-b pathway were simultaneously performed.

Methods: USSC cells were isolated from UCB and then coated on DBM scaffold as a feeder layer. UCB CD34+ cells were isolated from UCB by magnetic activated cell sorting (MACS) method and were transfected by siRNA against TGFbR2 in two-dimensional (2D) and three-dimensional (3D) cultures by co-cultivation with USSC. TGFbR2 expression levels were evaluated by quantitative real-time PCR. Cell count and flow cytometry were performed and clonogenic activity was evaluated.

Results: Ex vivo expansion of CD34+ cells was significantly enhanced (41±0.7 folds) by TGFbR2 downregulation, especially in 2D than 3D cultures. Finally, 2D culture showed less TGFbR2 expression levels and higher increase in the percentage of CD34 markers by flow cytometry assay.

Conclusion: The 3D siRNA delivery system would be of lower efficiency in contrast to 2D settings where the cells have less freedom and are in more contact with the feeder layer.


Nanofiber poly ether sulfone as adipose derived stem cell holding scaffold with or without growth factor on wound healing in rat
Mohammd Javad Fatemi , Shirin Chehroudi , Tooran Bagheri , Sahar Saleh , Amir Atashi , Mohsen Saberi , Seyed Aboozar Hoseini , Shirin Araghi ,
Volume 74, Issue 12 (3-2017)
Abstract

Background: Acute and chronic wound healing has always been problematic. Stem cells with or without the scaffold carrying these cells have been proposed as new methods in the treatment of wounds. In this case study we have tried to examine the effect of scaffold made of polyether sulfone (PES) alone, with stem cells and along with stem cell and growth factor on wound healing in rats.

Methods: This experimental study was conducted in Animal Laboratory of Hazrat Fatemeh Hospital in 2012. In this study, 48 rats were randomly divided into four groups. A wound created on the back of each rat at the size of 3×3 cm. The surface of the wound in the first group is covered with PES seeded with adipose-derived stem cell (ASC) and growth factor (GF), in the second group with polyether Sulfone seeded with ASC, in the third group only with PEWS, and in the fourth group (control) with Vaseline gauze. On 20th and 35th days, the surface of the wound was assessed by photography in order to understand the process of healing. In addition, on days 20 and 45, the histopathology characteristics of the samples were studied with a biopsy of the wounds.

Results: The Results of wound healing in the control group was better than the other groups and its statistical difference between others was meaningful. (P=0.008, P=0.013, P=0.001) On day 20, by examining histopathological characteristics including epithelialization, the number of inflammatory cells, the amount of angiogenesis and collagen synthesis in control group, we gained better results. (P=0.000), But on day 45, the results in different parameters were not equal.

Conclusion: polyether sulfone scaffold alone or with adipose-derived stem cells couldn’t improve the process of wound healing. Also adding vascular endothelial growth factor (VEGF) did not change the results significantly.

Advances in adipose-derived stem cells and cartilage regeneration: review article
Mohsen Sheykhhasan , Mahdieh Sadat Ghiasi ,
Volume 76, Issue 5 (8-2018)
Abstract
The cartilage is a connective tissue that, due to the strength of its extracellular matrix, allows the tissue to tolerate mechanical stress without undergoing permanent deformation. It is responsible for the support of soft tissues and due to its smooth surface and elasticity, gives the joints the ability to slip and bend. excessive weight, excessive activity, or trauma can all cause cartilage to injury. The injury can lead to swelling, pain and varying degrees of mobility loss. The process of repairing musculoskeletal (orthopedic) injuries has led to problems in the medical field, which can be attributed to the inherent weakness of adult cartilage tissue. Therefore, this necessitates research focused on the development of a new restructuring strategy by combining chondrocytes or stem cells with scaffolds and growth factors to address these problems. Correspondingly, the recent tissue engineering strategies strongly support the simultaneous use of stem cells, scaffolds and growth factors. It has also been observed that due to the relatively low proliferation of transplanted chondrocytes, new cartilage models construction have examined the use of adipose-derived stem cells. Mature adipose tissue is produced as an important source of multi-functional stem cells that can be easily separated from the stromal vascular fraction (SVF) by adipose liposuction digestion. The adipose-derived stem cells are easily accessible without any serious complications and have the power to differentiate into several cell lines, including chondrocytes as well as, they evidence self-renewal when trapped in gel scaffolds such as collagen. Also, recent studies demonstrate some of the mechanisms involved in the process of making cartilage of adipose-derived stem cells in vitro and their restorative ability in bio-engineered scaffolds in the presence of growth factors. In addition, the important role of non-encoding mRNA molecules (miRNAs) has been identified in the process of chondrogenic differentiation of adipose-derived stem cells. Furthermore, in several studies, the effect of several miRNAs has been confirmed on the regulation of the cartilage differentiation of the adipose-derived stem cells and has also been associated with effective results. In this article, we will present an overview of the advance in adipose-derived stem cells application in cartilage regeneration.

Preparation of acellular sciatic nerve scaffold and it’s mechanical and histological properties for use in peripheral nerve regeneration
Arash Abdolmaleki, Mohammad-Bagher Ghayour, Saber Zahri, Asadollah Asadi , Morteza Behnam-Rassouli ,
Volume 77, Issue 2 (5-2019)
Abstract
Background: Tissue engineering is a developing multidisciplinary and interdisciplinary field involving the use of bioartificial implants for tissue remodeling with the target for repair and enhancing tissue or organ function. Acellular nerve has been used in experimental models as a peripheral nerve substitute. The purpose of the present study was to evaluate the mechanical and histological characteristics of acellular nerve scaffolds compared to the fresh nerve for application in environmental nerve repair.
Methods: This experimental study was conducted in Ferdowsi University of Mashhad Regeneration Research Laboratory, Mashhad, Iran, from May 2017 to October 2018. In this study for preparing the scaffold. The rats were sacrificed by intraperitoneal anesthesia with 10 % Chloral Hydrate solution. Then sciatic nerve fragments of the rats were removed above the nerve branching site and after cleansing of the tissues were decellularized by Sondell method, briefly nerves were treated with a series of detergent baths consisting of distilled water for 8 h, Triton X-100 for 12 h, and sodium deoxycholate for 24 hours according to the Sondell protocol. All acellularization steps were performed at room temperature. Then decellularized scaffolds were evaluated histologically and mechanically.
Results: The results of tissue evaluations showed that decellularization of scaffolds were done completely, this was demonstrated by hematoxylin and eosin staining and DAPI staining. Also the specialized tissue evaluations by picro-fuchsin staining and evaluation the scaffolds by scanning electron microscopy (SEM) micrographs showed that the collagen and elastin strands are relatively preserved in the extracellular matrix in comparison with control groups. As well as mechanical examination of scaffolds in tensile test showed that extracellular matrix of scaffolds was relatively preserved the main components of tissue compared to control group and scaffolds have good mechanical resistance quality for use in tissue engineering.
Conclusion: The results of the present study showed that decellularized scaffolds that prepared with Sondell decellularization method by preserving the main components of the tissue can be a good platform for investigating cellular behaviors.

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