ناصر اقدمی

The direct approach of cardiac tissue engineering is to mimic the natural tissue of heart, considering the significant role of scaffolding and mechanical simulation. 

To achieve this purpose, a composite Polycaprolactone (PCL)/Gelatin electrospun scaffold with a ratio of 70:30 and with the most similarities to the cardiac extracellular matrix was fabricated with aligned nanofibers. The scaffold was evaluated using scanning electron microscopy (SEM), mechanical strength analysis, and contact angle test. To simulate the cardiac contraction, a developed Mechanical Loading Device (Bioreactor) was designed to apply a mechanical load with a specific frequency and tensile rate values in the direction of aligned nanofibers due to simulating natural cardiac tissue.

Based on our results from the contact angle and mechanical strength tests, we concluded that our designed scaffold has appropriate adhesion and strength to use as cardiac scaffold and is suitable for imposing the frequency of 1Hz and 10% strain. The Bioreactor also worked properly in producing the required frequency, tensile rate and temperature. 

Since an essential difference between cardiomyocytes and other cells is their contraction, manufacturing a biomimetic bioreactor to simulate the normal cardiac contraction of cardiomyocytes and their required temperature to be survived in-vitro could be a promising approach in cardiac tissue engineering.

 This research, design and fabrication of a composite scaffold for growth, proliferation and differentiation of Cardiac Progenitor Cells (CPCs) has been considered.

 Polycaprolactone / Gelatin composite scaffolds with a ratio of 70:30 and with the most similarities to the cardiac extracellular matrix was fabricated with aligned nanofibers. Using scanning electron microscopy (SEM), mechanical strength analysisand also contact angel test, the scaffold was investigated due to have the most necessary characteristics to be proportional for cardiac scaffold. Finally, By Real time-PCR test, the expression of the specific genes related to the Cardiac Progenitor Cells differentiation (MYH-6, TTN and CX-43) has been analyzed.

 Based on our results from contact angle test and mechanical strength experiments, we concluded that our designed scaffold is suitable for the culture of Cardiac Progenitor Cells on it. The Real time-PCR analysis also showed the good expression of genes associated with contraction.

 What makes the cardiomyocytes different from other cells is their contraction related to specific cardiac genes being responsible for beating synchronization. The results of this study showed that aligned Polycaprolactone / Gelatin composite scaffold has the appropriate potential for induction of cardiac progenitor cells differentiation and application in heart tissue engineering.

Re-epithelialization has an important role in skin wound healing. Delays in re-epithelialization are more likely to create the chronic wound. Impaired wound healing leads to a large burden of morbidity and mortality. Current treatments based on the use of autografts, allografts and xenografts, suffer from limitations such as, quantity of donor skin available, donor-site infection, potential risk of disease transmission and rejection of the graft. Given this problems, nanomaterial such as copper nanoparticles has attracted considerable research interest because of their high surface area to volume ratio, high stability, clinical safety, and antibacterial effects. Epithelialization involves keratinocyte migration and proliferation to the wound site. Therefore, this study was conducted to investigate the effect of copper nanoparticles on keratinocyte cell migration and proliferation. This experimental study was performed in Royan Institute, Tehran in 2016. In this study we investigated the effect of copper nanoparticles on viability, migration and proliferation of keratinocyte cells. Cultured human foreskin Keratinocyte cells were exposed to various concentration (1, 10 and 100 µmol) and sizes (40 and 80 nm) of copper nanoparticles for 24, 48 and 72 hours. The copper nanoparticles toxicity was examined by MTS assay. Cell migration has also been investigated with the Scratch assay. The results showed that the 1, 10 and 100 µmol concentrations of 40 and 80 nm copper nanoparticles were not toxic for cultured human foreskin keratinocyte cells after 24h. It was also found keratinocyte cell proliferation was increased by 1 µmol concentration of 80 nm copper nanoparticles after 72h. The results of the Scratch assay showed that the 1 µmol concentration of 80 nm copper nanoparticles significantly (P<0.05) increased keratinocyte cell migration compared to deionized water as of control group after 24h. It seems the 1 µmol concentration of 80 nm copper nanoparticle could stimulate keratinocyte cell migration and proliferation. However, in vivo studies conducted on animal model wound healing subjects are needed for determining re-epithelialization.

To evaluate result of Corneal graft (PKP) after cultivated oral mucosal epithelial transplantation (COMET) in patients with chemical burn.
In this prospective interventional nonrandomized case series, optical PKP was performed after successful COMET for visual rehabilitation in patients with severe stromal opacity. Main outcome measures were clarity of the corneal graft, visual acuity improvement, and corneal graft survival.
Fourteen eyes of 14 patients with successful COMET were included. Overall, PKP was performed 7.6±1.3 months (6-9 months) after COMET. The mean follow-up period was 28.2±8 months (14-40 months, median 30 months). The time for complete epithelial healing was 7 days in all eyes. There was no epithelial defect in 13 eyes at the final examination. The corneal surface had been covered by a transparent epithelium without significant neovascularization. Bacterial keratitis developed in 1 eye due to persistent epithelial defect, which was healed with vascularization. Best-corrected visual acuity increased from 2.67±0.08 LogMAR preoperatively to 0.64±0.27 LogMAR after PKP (P PKP is a good choice for visual rehabilitation in chemical burn with bilateral total LSCD and severe stromal opacity that underwent successful COMET.

Copper nanoparticles (Cu NPs) induced angiogenesis, has been adapted to respond the most important challenging in wound healing. But due to the toxicity of nanoparticles, the nontoxic concentrations is important. The aim of this study was to determine the concentration and size of copper nanoparticles for investigating the effect of its cytotoxicity on the endothelial cell.
In this study, we exposed Cu NPs (40nm) with concentrations of 1, 10, 100 μM and 1 ,10 mM to endothelial cells and evaluate its viability effect after 24, 48 and 72 hours, according to the MTS) Methy Thiazol Tetrazolium (assay. Its optical density was determined using an ELISA reader and then was recorded.
The findings demonstrated that Cu NPs was significantly (p The results showed that different concentration of Cu NPs in the 48 and 72 hours didn’t cause any cytotoxicity effect, but it stimulated endothelial cell proliferation. Therefore, Cu NPs with dose and time dependent effect has been increased endothelial cell proliferation.

Scleroderma- one of the important autoimmune diseases- leads to death of endothelial cells as one of the early events of this disease. The lack of repair after the loss of endothelial cells is observed in these patients and although, its cause has remained unknown. The development of effective treatments for many rheumatoid diseases requires a better understanding of the pathophysiological mechanisms involved in the disease. Because of physiological and anatomical and developmental differences between human and other species, a proper scleroderma animal model which represent all aspects of the disease has not been generated yet. So, making a patient-based system to mimic a developmental defect and evaluating its probable repair mechanism is considered as a necessity. For this reason, the development of a model system which can be an evaluation of molecular and developmental defects and also explain the possible repair mechanism, would be considered as a requirement. Like other studies, using patient-specific cell as a limitless source, could provide new hope for development of novel therapeutic approaches for patient with scleroderma.

The production of a sufficient number of pancreatic endocrine cells that function similarly to primary islets is one of the methods in treatment of diabetes. The CD133+ cells derived from cord blood (UCB-CD133) express some embryo specific markers such as SSEA-4 and OCT4 and so it can be a candidate for differentiation into insulin secreting cells. Therefore, here we attempt to determine the differentiation potential of UCB-CD133+ cells into insulin secreting cells in vitro. UCB-CD133+ cells were isolated by MACS and differentiated into insulin secreting cells using the medium containing DMEM/F12, bFGF, Nicotinamid, and supplement B27 N2 for 9 days. The expression of insulin and c-peptide protein was detected by immonocytochemistry. The expression of insulin, Nkx6.1, Pdx1, and Glocagon genes was analyzed by RT-PCR; ELISA was performed to analysis the function of differentiated cells in different glucose concentrations (5 and 27 mM). Our results determined that UCB-CD133+ cells expressed insulin and c-peptide at protein level after 9 days of culture. However, the insulin, Nkx6.1, Pdx1, and Glocagon genes were not detected in differentiated cells and they could not respond to different concentrations of glucose. We suggested that UCB-CD133+ cells can differentiate into insulin secreting cells in vitro; however, they are not functional and need to receive more signals in vivo.

Synthesis of extracellular matrix (ECM) is a key factor in wound healing. The predominant component of ECM is hyaluronic acid (HA). Recent studies have shown that adipose derived stem cell-conditioned medium (ADSC-CM) can increase the expression and synthesis of collagen I, III and fibronectin which are the components of ECM. The purpose of this study was to investigate the effects of ADSC-CM on the expression of HA synthase and degrading genes in human dermal fibroblasts (HDF). ADSCs were isolated from three liposuction samples and their conditioned medium was collected. Skin biopsies were isolated from six patients and their fibroblasts were isolated. These cells were cultured in 100% of ADSC-CM. Expression of three HA synthase and two hyaluronidase genes were assessed with the use of real time PCR, with ELISA and final amounts of secreted HA were measured in the treated and control groups. Gene expression of two HA synthase genes HAS1 and HAS2 were upregulated in treated samples compared to the control group. The expression of one hyaluronidase gene, HYAL2, was downregulated in them. Final amount of HA was increased in the treated samples. The expression and synthesis of HA can be increased by the stimulatory effect of growth factors present in ADSC-CM. Thus, secretomes of ADSCs could play a crucial role in wound healing by up-regulating the production of ECM’s components in HDFs.

Human embryonic stem cells (hESCs) are capable of self-renewal and large-scale expansion. They also have the capacity to differentiate into a variety of cell types including liver, cardiac and neuron cells. However, it is not yet clear whether hESCs can differentiate to hemangioblasts under in-vitro conditions. Hemangioblasts are bipotential progenitors that can generate hematopoietic lineages and endothelial cells. The aim of this study was to identify the potential of human Royan H5 embryonic stem cells in differentiating into hemangioblast cells. HESCs were cultured at suspension system in DMEM/F12 supplemented with bFGF. 7-day old cells differentiated into blast cells under defined condition consisting of hematopoietic cytokines including BMP4, VEGF, etc. Blast cell markers kinase insert domain receptor (KDR), CD31, and CD34 were evaluated by flow cytometry and blast gene expressions (TAL-1, Runx-1 and CD34) were detected by qRT-PCR. Clonogenic assays were performed in semisolid medium by colony forming unit-assays. The hESCs (Royan H5) had the capacity of differentiating into hemangioblast cells. We could detect colonies that expressed 79%±12.5 KDR+, 5.6%±2.8 CD31+-CD34+ and 6%±2.12 KDR+-CD31+ on day 8 in the hESCs. Up-regulation of TAL-1, Runx-1 and CD34 occurred during hemangioblast commitment (P≤0.05 and P≤0.01, respectively). Moreover, hemangioblast cells generated mixed-type and endothelial-like colonies in semi-solid media. Our results showed that hESCs (Royan H5) were able to differentiate into hemangioblasts under in-vitro conditions. The hemangioblasts had the potential to generate two non-adherent (Mixed-type) and adherent (endothelial-like) cell populations.

Skin injury caused by burns, surgery and other traumas may result in unpleasant psychological experiences and be reflected in behaviors. Extracellular matrix (ECM) is the largest component of natural skin which is gel-like and is produced by skin cells. ECM synthesis is a key factor for filling up skin wounds such as burns, leishmaniasis, chicken pox, acne, etc. ECM is composed of a variety of polysaccharides, water, and collagen proteins. Considering its weight, natural skin strength and its expandability are like steel, while it has high elasticity and compaction capacities. These characteristics are due to dual effects of main ECM molecules, which are secreted by fibroblasts and epidermal cells: 1) structural fiber proteins like: elastin, fibronectin and laminin which give strength and flexibility to ECM, and 2) proteoglycans such as dermatan sulfate and hyaluronic acid which are consisted of few glycosaminoglycan chains that branch out from a linear protein core. Proteoglycans are large and hydrated molecules which are resistant to external forces and protect underneath cells. In general, understanding the skin structure and wound healing phases can help us to design useful experiments and to conduct proper researches in this area.

Hyaluronic acid (HA), the main and most important constituent of extracellular matrix, is a glycosaminologycan with water-absorbing capacity found in large amount in growing and repairing tissues. One of the main causes of skin problems, particulary in aging skin, is HA deficiency. More than half of the body HA is in the skin and is necessary for the maintenance of internal matrix and several cellular functions. Filler gels containing HA are used to repair skin defects. As these substances are derived from animals and bacteria, not the human, may cause skin reactions and have short half-life. So efforts to maintain and/or increase HA secretion from skin fibroblasts are important in the prevention and treatment of skin aging.

Mesenchymal stem cells (MSCs) derived from bone marrow are multi potent cells that have the capacity to trans-differentiate into a variety of cell types including insulin islet cells. However the efficiency is low. The aim of this study is to explore the potential of Marrow and Umbilical cord vein MSC to differentiate into functional islet like cells in vitro.

BM-MSCs and UC-MSCs were obtained from healthy donors and were cultured. MSCs with high CD90, CD73, CD105, CD44 and very low CD34 and CD45 expression were differentiated into Islet-like cells, under defined conditions. Insulin and c-peptide positive cells were evaluated with immune-florescence and insulin release after glucose challenge was tested by ELISA. QRT-PCR was done to detect expression of insulin, Glut2, Nkx6.1 and Nkx2.2 at mRNA level.

Our results showed that only BM-MSC can be differentiated to insulin secreting cells. About 15.8%±2.6 and 13.5%±5.5 of cells were positive for insulin and c-peptide, respectively. Our results revealed that expression of Insulin and Glut2 upregulated 20 fold changes at mRNA level. However they were not functional when treated by different concentration of glucose.

Our results showed that only Human BM-MSCs, compared to umbilical cord vein MSCs, are able to differentiate into insulin producing cells in vitro.

Systemic scleroderma (SSc) is a generalized connective tissue disorder of unknown origin which most notably is characterized by skin thickening and organ damage. Endothelin-1 (ET-1) antibody plays a role in skin fibrosis. The aim of this study was to determine the prevalence and correlation of different manifestations of SSc with ET-1 plasma levels. This cross-sectional analytical study was conducted on 95 patients (91 women and four men) with scleroderma in 2006.

Tracking cells after transplantation is always one the main concerns of researchers in the field of regenerative medicine. Finding a tracer with long stability and low cytotoxicity can be considered as a solution for this issue. Semiconductor nanocrystals, also called quantum dots (QDs), have unique photophysical properties which make them as suitable candidate in this setting. Broad-range excitation, size-tunable narrow emission spectrum, high brightness and their exceptional resistance against photobleaching are among characteristics which enable the researchers to use these nanoparticles in long-term, multi-target and high sensitive in vivo imaging of live animals. However, due to the toxic components found in QDs core caution must be exercised in their clinical usage. This review summarizes the role of QDs in cellular tracking and is concerned about theirpotential cytotoxicity.

Insulin dependent diabetes is an autoimmune disease characterized as a T cell-mediated destruction of insulin-producing β cells. Dendritic cells (DCs) can either induce stimulating or regulatory functions of T cells depending on cytokines microenvironments. In this study DCs were generated from mouse bone marrow progenitors through culturing in the presence of granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin-4 (IL-4) for 7 days followed by two other day treatments with IL-10 or LPS. The DCs were then pulsed with insulin peptide B9-23 and their maturation markers and their ability to induce T cell responses and cytokine profiles were studied. IL-10 treated DCs had an immature phenotype compared to LPS-treated DCs and expression of MHC-II in LPS-matured DCs was significantly higher than whom were treated with IL-10 (93% and 72% respectively, P<0.04). Although IL-10 like LPS-treated DCs were able to stimulate T cell proliferation, but the IFN-γ production was lower in IL-10 treated DCs (P<0.02). Using IL-10 treated DCs seems to be useful in prevention and treatment of autoimmune diabetes. However to clarify this hypothesis it needs to study these effects in animal models of insulin dependent diabetes.