Tehran University Medical Journal

Stem cells are undifferentiated biological cells that can differentiate into more specialized cells and divide (through mitosis) to produce more stem cells (self-renew). In mammals, there are two broad types of stem cells: embryonic stem cells, which are isolated from the inner cell mass of blastocysts, and adult stem cells, which are found in various tissues. Mesenchymal stem cells (MSCs) are multipotent cells that are called as one of the most adult stem cells. Due to their highly proliferative potential and their suitable self-renewal capacity, these cells have provided a powerful and promising source for use in the field of regenerative medicine. Also, mesenchymal stem cells are known for their important properties involving multilineage differentiation potential, trophic factor secretion and localization along various organs and tissues. So that MSCs can differentiate into a variety of cell lineages, including: Osteoblasts (bone cells), chondrocytes (cartilage cells), adipocytes (fat cells), myocytes (muscle cells), hepatocytes (liver cells) and endothelial cells. Efficacy of differentiated MSCs to regenerate cells in the injured tissues requires the ability to maintain the differentiation toward the desired cell fate. Since MSCs represent an attractive source for autologous transplantation, cellular and molecular signaling pathways and micro-environmental changes have been studied in order to understand the role of cytokines, chemokines, and transcription factors on the differentiation of MSCs. The differentiation of MSC into a mesenchymal lineage is genetically manipulated and promoted by specific transcription factors associated with a particular cell lineage. Recent studies have explored the integration of transcription factors, including Runx2, Sox9, PPARγ, MyoD, GATA4, and GATA6 in the differentiation of MSCs. Therefore, the overexpression of a single transcription factor in MSCs may promote trans-differentiation into specific cell lineage, which can be used for treatment of some diseases. In this review, we critically discussed and evaluated the role of transcription factors and related signaling pathways that affect the differentiation of MSCs toward adipocytes, chondrocytes, osteocytes, skeletal muscle cells, cardiomyocytes, and smooth muscle cells.
 

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.

Background: Thrombopoietin (TPO) is an important cytokine that has a critical role in regulating hematopoietic stem cells (HSCs) proliferation and megakaryocyte differentiation. Because of scares amount of this protein in human plasma, in many biotechnological centers around the world, recombinant production of this protein has been carried out. This study was aiming to gene cloning and expression of recombinant thrombopoietin.
Methods: This research is an experimental laboratory study carried out in Blood Transfusion Research Center, Tehran, Iran, from July 2016 to August 2017. At the beginning HepG2 cell line was cultured and RNA extraction was performed. Extracted RNA was used as template for cDNA synthesis and subsequently the synthesized cDNA was adopted to isolate TPO gene through polymerase chain reaction (PCR) reaction using designed primers. After isolating the TPO sequence from HepG2 cell line, the designated sequence was inserted into pET32 vectors. Recombinant plasmid was amplified by meriting from DH5α replicating system. The amplified plasmids were sequenced via chain termination method. Next step was transforming the recombinant plasmid into Rosetta-gami bacteria to express the recombinant protein. In order to induce protein expression, an appropriate amount of isopropyl β-D-1-thiogalactopyranoside (IPTG) was added to growth media, then bacterial lysate of expression host was prepared and assayed via polyacrylamide gel electrophoresis and western blotting test.
Results: After sequencing of recombinant plasmid, it was confirmed that TPO sequence has been successfully colonized in adopted vector. Subsequent to induction of recombinant protein, total cell protein analysis affirmed that recombinant protein has been expressed in its soluble form at cytoplasmic condition. Location of expected recombinant protein band on polyacrylamide gel and reaction of recombinant protein with His-tag monoclonal antibody at western blotting was asserting that expressed protein is the one of interest.
Conclusion: Rosetta-gami bacteria has capability of expressing recombinant thrombopoietin in its soluble form. By harnessing this method of recombinant protein expression, it would be possible to take advantage of high throughout bacterial expression system which would not produce inclusion body and its product doesn’t need further processing and refolding.

The mammalian cochlea is a highly complex structure which contains several cells, including sensory receptor or hair cells. The main function of the cochlear hair cells is to convert the mechanical vibrations of the sound into electrical signals, then these signals travel to the brain along the auditory nerve. Auditory hair cells in some amphibians, reptiles, fish, and birds can regenerate or replace by new cells, but irreversible damage to the mammalian hair cells are not being replaced through differentiation of the internal epithelial cells in the inner ear. Indeed, mammalian auditory hair cells do not spontaneously repair or regenerate after development. Sometimes, functions of damaged hair cells may be restored, but in most cases, there is no such possibility and permanent hearing loss occurs. Several factors such as chronic ear infections, genetic disorders, drug abuse, acoustic trauma and aging can damage the cochlea, resulting in permanent hearing loss. More than 250 million people in the world have disabling hearing impairment. Deafness is caused by damage to sensory hair cells or spiral ganglion neurons. Although hearing aids and cochlear implants were used for improvement of hearing loss, but they do not restore normal hearing. In addition, application of new biological approaches to induce auditory hair cell regeneration provides more comprehensive treatment for hearing loss. Cell therapy is considered a promising way in the treatment of several diseases such as Parkinson, diabetes and cardiac diseases. According to recent research, cell therapy can be useful in hair cell regeneration. Cell therapy is effective in hearing loss when stem cell differentiates into hair cells with appropriate morphology, electrical activity and capacity for suitable innervations with inner ear tissues. In fact, stem cell-derived neurons need to project neural processes toward the sensory hair cells and the cochlear nucleus neurons. In this regard, studies focus on methods in which hair cells can be provided from exogenous and endogenous stem cells. Here, we review cell therapy approaches in repair damaged cochlear hair cells, as well as imitations and problems of its clinical application.

Chick embryos are a great historical research model in basic and applied sciences. Along with other animal models, avian and specifically chicken embryo has been attended, as well. Avian fertilized eggs as a natural bioreactor are an efficient tool for producing recombinant proteins and vaccines manufacturing. Due to the limitations of birds' eggs for viral replication, avian stem cells culture technologies access to safe methods as well as large-scale production of a variety of human and animal vaccines. Chicken pluripotent stem cells present the unique property of self-renewal and the ability to generate differentiated progeny in all embryonic lineages such as ectoderm, mesoderm, and endoderm in vitro. For the first time, chicken embryonic stem cells (cESCs) derived from the blastodermal cells of stage X embryos in vitro. Chicken ESC provides a great model of early embryo and they are useful for gene manipulation, virus proliferation, and the generation of transgenic birds. In addition to blastodermal cells, pluripotent cell lines can be produced by reprogramming of chicken fibroblasts into induced pluripotent stem cells (iPSCs) with transcription factors such as OCT4, NANOG, SOX2, KLF4, LIN28, and C-MYC that are well known to contribute to the reprogramming of somatic cells into an iPSCs. Similar to chicken ESCs, iPSCs have properties of unlimited self-renewal in vitro and the capacity for differentiation to all three embryonic germ layers. Chicken iPSCs have been a useful tool for the production of transgenic birds and viral vaccines. Despite the benefits and multiple applications of chicken pluripotent stem cells, the propagation of these cells is limited and some important challenges should be eliminated before their use in vaccine manufacturing. It is necessary to define the appropriate culture conditions for chicken pluripotent stem cells. For example, the presence of endogenous viruses in the avian species should be evaluated for human vaccine production. Currently, primary chicken fibroblast cells are still mainly used for vaccine production. This review covers the resources to achieve chicken derived cell lines for vaccine manufacturing.

Background: The application of mesenchymal stem cells in the healing of chronic wounds is one of the most challenging issues in cell therapy. The present study investigated the efficacy of intradermal injection of umbilical cord Wharton's Jelly-derived mesenchymal stem cells in diabetic wound healing using ultrasound imaging in an animal model.
Methods: During this experimental laboratory study that was performed in the Skin and Stem Cell Research Center, Tehran University of Medical Sciences between October 2017 and October 2016, mesenchymal stem cells were isolated from umbilical cord Wharton's jelly of 10 neonates. The cells were passage. The differentiation potential of cells to osteocyte and adipose cells was evaluated. The expression of specific markers of mesenchymal stem cells was evaluated using flow cytometry. The viability and quality of cells were evaluated before transplantation. The diabetes model was developed by intraperitoneal injection of streptozotocin in 42 male Wistar rats. The animals were randomly divided into two groups: normal saline injection (control) and cell injection. Cell transplantation was performed intradermally. Skin thickness and density were assessed using ultrasound imaging on days 7, 14 and 21. Finally, the data were analyzed using a t-test and analysis of variance.

Background: Low-level lasers are used for various medical applications including wound healing and hair loss treatment. Cell Therapy using skin stem cells could be a novel approach to hair transplantation. However, there is no study on the effect of low-level laser on the hair follicle stem cells. So, in this study, we investigated the effect of low level laser irradiation on viability and ROS production in the hair follicle stem cells.
Methods: This study was performed in the cell culture laboratory of Medical Laser Research Center, Yara Institute in 2020 (June 2020 to February 2020). The hair follicle was isolated from the Safe Donor Area (SDA) using the 4mm punch method. In the laboratory, after separating the follicular units, the bulb region of each follicle was isolated via mechanical and enzymatic methods and cultured in FBS+F12-DMEM. Afterward, the stem cells were characterized via flow cytometry. The effect of low-level laser (685 nm) with different doses (1-20 J/cm²) was investigated on cell proliferation, viability and ROS production.

Background: Cerebral palsy is a movement disorder syndrome in early childhood. Signs and symptoms vary among people and over time but include poor coordination, stiff muscles, and weak muscles. Some affected children can achieve near-normal adult lives with appropriate treatment. In recent years, transplantation of human mesenchymal stem cells (hMSC) has become a promising therapeutic strategy for CP. Every year, a lot of costs are spent on the treatment and management of this disease. The purpose of this study is to investigate the safety and effectiveness of this method on CP.

Methods: This article is a systematic review. At first, a search strategy was written and performed in Scopus, PubMed, and Google Scholar databases(The search was conducted from March 14 to March 28, 2021), and the inclusion and exclusion criteria were determined. Study inclusion criteria: review studies, cohort studies, clinical trial studies (randomized and non-randomized), control case, and retrospective , exclusion criteria: non-English articles and studying on animals. After removing duplicate articles, two authors independently reviewed the studies according to the inclusion and exclusion criteria. Disagreements among the authors were resolved through discussion.
Findings: In total, 9236 articles were found in the initial search, after reading the titles, of 37 articles, 21 articles were selected in the abstract stage and 18 articles remained in the full-text stage. We finally found 18 articles that showed that using stem cell technology as a scientific method could improve sick patients’ quality of life and movement defects.
Conclusion: According to the available evidence and limited studies, stem cell technology can be safeand cost-effective in improving CP patients, but there is insufficient evidence. On the other hand, there are many studies confirming the effectiveness of these cells in the treatment of movement impairment. In conclusion, stem cells may have a very promising future. Finally, stem cell technology combined with innovative biotechnologies may soon bring promising results to patients.

Background: Stem cells play an important role in tissue regeneration and treatment of diseases. This study aimed to investigate the awareness, knowledge and attitudes regarding stem cell donation among different people in the community.
Methods: In this systematic review study, Persian keywords and English keywords such as awareness, knowledge, stem cells, embryonic stem cells, adult stem cells, cord blood stem cells and donation were selected according to MeSH database and then these selected keywords have been searched in the academic databases such as PubMed, Scopus, OVID, Science Direct, Iran Medex and SID. In addition, these selected keywords have been searched in the search engines such as Google Scholar, between January 2010 to December 2021.

Results: The results of this study found a total of twenty-five articles related to the awareness, knowledge and attitudes regarding stem cell donation among different people in the community. They were selected. In this study there were 10 cross-sectional studies, 2 descriptive-cross-sectional studies, 5 descriptive studies, 1 mixed method study, 1 semi-experimental study, 1 intervention study, 1 survey study, 1 review study, and the study type was not mentioned in three studies. Most of the studies were conducted in countries such as India, Saudi Arabia, and then United States (USA) and Turkey. Only one article was found in Iran. The results of studies have shown that the level of awareness and attitude of the majority of different people in the community towards the donation and use of stem cells is medium and low. However, most people have a good and positive attitude towards the donation and use of stem cells and mention the use of stem cells as an effective way to treat diseases. Conclusion: Considering the importance and application of stem cells, it is suggested that managers and planners provide the necessary conditions to implement educational programs to raise the level of awareness and attitude of different people in the community towards stem cell donation.

Background: Mesenchymal stem cell (MSC) transplantation is a promising therapy for kidney repair. This study compared the regenerative effects of feline MSCs (fMSCs) and telmisartan, a renin-angiotensin blocker (RAB), in a feline model of chronic kidney disease (CKD).
Methods: The fMSCs were obtained from 35 Persian cats with CKD and characterized by CD44, CD90, and CD105 markers by using real-time RT-qPCR. The cats were randomly allocated to four groups, fMSCs injection (first group), telmisartan administration (second group), no treatment (third group), and healthy controls (fourth group). The study was conducted in Kerman province from December 2018 to December 2019. The factors that may affect the risk of CKD, such as age, weight, and history of kidney diseases, were considered as independent variables. The presence or absence of CKD was the dependent variable. The cats were followed up for 120 days and evaluated by physical examination, glomerular filtration rate (GFR), blood urea nitrogen (BUN), serum creatinine (SCr), serum urea, alanine transaminase (ALT), urine specific gravity (SG), and kidney histopathology. Statistical analysis was performed using SPSS software (version 20) with two-way ANOVA and Tukey test. P<0.05 was considered statistically significant.

Results: The fMSCs group showed significant improvement in GFR, BUN, SCr, serum urea, SG, and kidney histology compared to the other groups. The fMSCs group also showed increased expression of CD44, CD90, and CD105 genes in the kidney tissue, indicating enhanced stem cell activity. The telmisartan group showed modest improvement in blood pressure and proteinuria, but no significant effect on other parameters. fMSCs transplantation can restore the kidney function and structure in cats with CKD by modulating the apoptosis and proliferation of renal cells. The telmisartan  patients benefited from the anti-hypertensive and anti-proteinuric effects of the drug, but not from its anti-fibrotic or anti-inflammatory effects. Conclusion: fMSCs transplantation was more effective than telmisartan in improving kidney function and reducing kidney damage in cats with CKD. fMSCs may be a potential therapeutic option for CKD patients.