Therapeutic Effects of Mesenchymal Stem Cell-Derived Extracellular Vesicles in sepsis: a Systematic Review and Meta-Analysis of Preclinical Studies.

BACKGROUND: Sepsis is a life-threatening disorder with no definitive cure. Preclinical studies suggest that extracellular vesicles derived from mesenchymal stromal cells (EV-MSCs) can mitigate inflammatory conditions, potentially leading to increased survival and reduced organ dysfunction during sepsis. Our aim to conduct this systematic review and meta-analysis is assessing the EV-MSCs therapeutic efficacy in sepsis. METHODS: PubMed, Embase, Scopus, WOS and ProQuest databases and also Google Scholar search engine were searched for published articles. We used hazard ratio (HR) and standardized mean difference (SMD) as effect sizes to evaluate the therapeutic effect of EV-MSCs on survival rate and determine their effect on reducing organ dysfunction, respectively. Finally, we employed GRADE tool for preclinical animal studies to evaluate certainty of the evidence. RESULTS: 30 studies met the inclusion criteria for our article. Our meta-analysis results demonstrate that animals treated with MSC-EVs have better survival rate than untreated animals (HR = 0.33; 95% CI: 0.27-0.41). Our meta-analysis suggests that EV-MSCs can reduce organ dysfunctions in sepsis, such as the lung, kidney, and liver. Additionally, EV-MSCs decrease pro-inflammatory mediators like TNF-α, IL-1ß, and IL-6. CONCLUSION: Our results indicate that EV-MSCs can be as promising therapy for sepsis management in animal models and leading to increased survival rate and reduced organ dysfunction. Furthermore, our study introduces a novel tool for risk of bias assessment and provides recommendations based on various analysis. Future studies with aiming to guide clinical translation can utilize the results of this article to establish stronger evidence for EV-MSC effectiveness.

Biological study of skin wound treated with Alginate/Carboxymethyl cellulose/chorion membrane, diopside nanoparticles, and Botox A.

A hydrogel-based wound dressing with desirable properties is necessary for achieving functional skin integrity post-injury. This study focuses on preparing a hydrogel using Alginate/Carboxymethyl cellulose (Alg/CMC) as a base material. To evaluate its regenerative effects on full-thickness wounds, diopside nanoparticles and Botulinum toxin A (BTX-A) were incorporated into the hydrogel along with chorion membrane. The diopside nanoparticles (DNPs) act as a proangiogenic factor, promoting proliferation and regulating inflammation, while the chorion membrane facilitates these processes. Additionally, BTX-A prevents scar formation and aids in wound closure. The nanoparticles and hydrogel were characterized using various techniques, and their cytocompatibility was assessed. In vivo studies and quantitative polymerase chain reaction analysis showed that wound area reduction was significant after two weeks of treatment with the Alg/CMC/ChNPs/DNPs/BTX-A hydrogel. Overall, this scaffold demonstrated potential for promoting tissue regeneration and new epithelization formation, making it a promising candidate for enhancing skin restoration in wound treatments.

Effects of Tumor Microenvironment on the Primo Vascular Pattern in the Mouse Model of Metastatic Breast Cancer.

Background: : Tumor survival, promotion, and metastatic functions are regulated by the tumor microenvironment (TME). The primo vascular system (PVS), the third circulatory system in animals, is currently thought to be a highly effective pathway for the spread of cancer cells. Objectives: : In the present study, we intend to determine the TME effects on the PVS pattern in breast cancer for the first time. Methods: : Heterotopic and orthotopic metastatic triple-negative breast cancer (TNBC) mice models were created. After 35 days, the skin was retracted, and a 2 cm skin incision was made up and down from the surface of the tumor tissue. In preparation for PVS staining, the dyes (trypan blue and alamarBlue) were injected throughout the tumor tissues. Under a stereomicroscope, PVS in heterotopic and orthotopic tumors was seen. Results: : According to our data, there are no appreciable variations in PVS patterns and density between heterotopic and orthotopic animal models. Furthermore, alamarBlue is a good option for tumor PVS staining, as demonstrated by our research. Conclusion: : For the first time, our data gave significant new information about the PVS in TNBC. Creating new anti-cancer treatments may be made possible by a better understanding of the biological characteristics of the TME and PVS.

Upregulation of Matrix Metalloproteinases in the Metastatic Cascade of Breast Cancer to the Brain.

BACKGROUND: In patients with triple-negative breast cancer (TNBC), brain metastasis is a fatal consequence. Matrix metalloproteinases (MMPs), especially MMP-2 and MMP-9 as the major members of the MMP family, are involved in many different facets of breast cancer metastasis. AIMS: In this study, we sought the MMPs expression in the metastatic cascade of TNBC. METHODS AND RESULTS: Primary breast cancer cells known as 4T1T were extracted from the tumor mass following the creation of an animal model of TNBC. The brain metastasis lesions of malignant mice were used to extract highly brain metastatic tumor cells known as 4T1B. Gelatinase zymography and real-time polymerase chain reaction (RT-PCR) were used to examine the expression of MMPs at the proteomic and transcriptomic levels in 4T1T and 4T1B. Our results indicated; brain metastatic tumor cells greatly increased their expression of MMPs. In 4T1B, MMP-2 and MMP-9 gene expression were upregulated by 4 and 3.4 folds respectively. Zymographic analysis found MMP activity only in 4T1B. CONCLUSION: These results offer significant information about the massive alteration of MMPs expression in the brain metastasis of TNBC. By analyzing the molecular characteristics of brain metastatic tumor cells, we can understand the molecular and genetic features of brain metastasis and develop tailored therapeutic strategies to combat TNBC brain metastasis.

Recent advances on 3D-printed PCL-based composite scaffolds for bone tissue engineering.

Population ageing and various diseases have increased the demand for bone grafts in recent decades. Bone tissue engineering (BTE) using a three-dimensional (3D) scaffold helps to create a suitable microenvironment for cell proliferation and regeneration of damaged tissues or organs. The 3D printing technique is a beneficial tool in BTE scaffold fabrication with appropriate features such as spatial control of microarchitecture and scaffold composition, high efficiency, and high precision. Various biomaterials could be used in BTE applications. PCL, as a thermoplastic and linear aliphatic polyester, is one of the most widely used polymers in bone scaffold fabrication. High biocompatibility, low cost, easy processing, non-carcinogenicity, low immunogenicity, and a slow degradation rate make this semi-crystalline polymer suitable for use in load-bearing bones. Combining PCL with other biomaterials, drugs, growth factors, and cells has improved its properties and helped heal bone lesions. The integration of PCL composites with the new 3D printing method has made it a promising approach for the effective treatment of bone injuries. The purpose of this review is give a comprehensive overview of the role of printed PCL composite scaffolds in bone repair and the path ahead to enter the clinic. This study will investigate the types of 3D printing methods for making PCL composites and the optimal compounds for making PCL composites to accelerate bone healing.

Downregulation of circ-Foxo3 in breast cancer stem-like cells.

OBJECTIVE: Cancer cells having stem cell characteristics are linked to metastasis and relapse in breast cancer. Circ-Foxo3, as a circular RNA, has been linked to the breast cancer lethal traits. This study's objective was to assess circ-Foxo3 expression in breast cancer stem-like cells. After isolation from tumor mass, breast cancer cells were subjected to the reliable in vitro assay of spheroid formation to determine the presence cancer stem cells (CSCs). We used a quantitative real-time polymerase chain reaction to examine circ-Foxo3 expression in spheroids. RESULTS: Circ-Foxo3 expression was significantly downregulated in spheroid-forming tumor cells, according to our data. This study demonstrated that breast CSCs have downregulated circ-Foxo3 expression, which may allow these cells to evade apoptosis. A precise analysis of this circRNA's role could be exploited to develop focused therapeutic approaches to fight breast CSCs.

Expression analysis of genes involved in the expansion of hematopoietic stem cells (SCF, Flt3-L, TPO, IL-3, and IL-6) in unrestricted somatic stem cells cultured on fibrin.

Umbilical cord blood (UCB) transplantation is a promising therapeutic approach for patients lacking HLA-matched donors. A main limitation to the use of UCB-derived HSCs (UCB-HSCs) is the low number of transplantable cells. Novel culture strategies are being developed to increase the number of HSCs. Unrestricted somatic stem cells (USSCs) have been identified as promising stromal cells for supporting HSC expansion. The current study aimed to explore the effect of fibrin on the expression of hematopoiesis-related genes (SCF, Flt3-L, TPO, IL-3, and IL-6) in USSCs. USSCs were isolated from UCB and characterized by flow cytometry and in vitro multilineage differentiation ability. DAPI staining and the MTT assay were used to assess the effect of fibrin on USSC viability. The cell attachment was evaluated using SEM. qRT-PCR was performed to evaluate the expression of SCF, Flt3-L, TPO, IL-3, and IL-6 in USSCs cultured on 3D fibrin scaffolds. USSCs were positive for CD73, CD105, and CD166 and negative for CD45. Alizarin red and Oil red O stains confirmed calcium deposition and lipid vacuoles in USSCs. Results obtained from DAPI and MTT assays revealed a positive effect of fibrin on USSC viability. Cells cultured on fibrin express significantly higher levels of SCF and TPO compared to those grown in a 2D environment. The positive effect of fibrin on IL-6 levels was reversed. Fibrin did not affect Flt3-L expression and IL-3 mRNA expression was not detected in either group. The results of this study provide the basis for developing further research on the ex vivo expansion of HSCs with USSCs.

Evaluation of Expansion and Maintenance of Umbilical Cord Blood CD34+ Cells in The Co-Culture with Umbilical Cord Blood-Derived Mesenchymal Stem Cells in The Presence of Microcarrier Beads.

OBJECTIVE: Umbilical cord blood (UCB) is an accessible and effective alternative source for hematopoietic stem cell (HSC) transplantation. Although the clinical application of UCB transplantation has been increased recently, quantitative limitation of HSCs within a single cord blood unit still remains a major hurdle for UCB transplantation. In this study we used microcarrier beads to evaluate the ex vivo expansion of UCB-derived HSCs in co-cultured with UCB-derived mesenchymal stem cells (MSC). MATERIALS AND METHODS: In this experimental study, we used microcarrier beads to expand UCB-derived MSCs. We investigated the simultaneous co-culture of UCB-derived CD34+ cells and MSCs with microcarrier beads to expand CD34+ cells. The colony forming capacity and stemness-related gene expression on the expanded CD34+ cells were assessed to determine the multipotency and self-renewal of expanded cells. RESULTS: Our results indicated that the microcarrier-based culture significantly increased the total number and viability of UCB-derived MSCs in comparison with the monolayer cultures during seven days. There was a significant increase in the UCB-derived CD34+ cells expanded in the presence of microcarrier beads in this co-culture system. The expanded UCB-derived CD34+ cells had improved clonogenic capacity, as evidenced by higher numbers of total colony counts, granulocyte, erythrocyte, monocyte, megakaryocyte colony forming units (CFU-GEMM), and granulocyte-monocyte colony forming units (CFU-GM). There were significantly increased expression levels of key regulatory genes (CXCR4, HOXB4, BMI1) during CD34+ cells self-renewal and quiescence in the microcarrier-based co-culture. CONCLUSION: Our results showed that the increase in the expansion and multipotency of CD34+ cells in the microcarrierbased co-culture can be attributed to the enhanced hematopoietic support of UCB-derived MSCs and improved cell-cell interactions. It seems that this co-culture system could have the potential to expand primitive CD34+ cells.

The effect of microvesicles derived from K562 cells on proliferation and apoptosis of human bone marrow mesenchymal stem cells.

Objectives: Microvesicles (MVs) are small membrane-bound particles that act as a vehicle to transfer their contents, such as proteins, RNAs, and miRNAs, to the target cells, making them undergo several changes. Depending on the origin and the target cell, MVs may cause cell survival or apoptosis. This study investigated the effects of MVs released from the leukemic K562 cell line on the human bone marrow mesenchymal stem cells (hBM-MSCs) to evaluate changes in the survival or apoptosis of the cells in an in vitro system. Materials and Methods: In this experimental study, we added the isolated MVs from the K562 cell line to hBM-MSCs, and after three and then seven days, subsequently cell count, cell viability, transmission electron microscopy, tracing MVs by carboxyfluorescein diacetate, succinimidyl ester (CFSE) solution, flow cytometry analysis for Annexin-V/PI staining and qPCR for the evaluation of BCL-2, KI67, and BAX expression were carried out. On the 10th day of the culture, hBM-MSCs were examined by Oil red O and Alizarin Red staining to evaluate their differentiation into adipocytes and osteoblasts. Results: There was a significant decrease in cell viability and KI67 and BCL-2 expression; however, BAX was significantly upregulated in the hBM-MSCs compared to control groups. Annexin-V/PI staining results also showed the apoptotic effects of K562-MVs on hBM-MSCs. Moreover, the differentiation of hBM-MSCs into adipocytes and osteoblasts was not observed. Conclusion: MVs from the leukemic cell line could affect the viability of normal hBM-MSCs and induce cell apoptosis.

Evaluation of anticancer effects of frankincense on breast cancer stem-like cells.

BACKGROUND: Relapse and metastasis in breast cancer are linked to cancer stem cells (CSCs) resistant to anticancer therapies. The presence of cancer stem-like cells (CSLCs) and their ability to self-renew is determined by in vitro spheroid formation. AIMS: Many studies have found that frankincense has anticancer impacts, although these effects on breast CSLCs have never been evaluated. METHODS AND RESULTS: A population of heterogeneous breast tumor cells was extracted from the tumor mass after generating an animal model of triple-negative breast cancer (TNBC). Spheroid formation was used as an in vitro assay to determine the existence of CSLCs in these cells. MTT assay was used to determine frankincense's cytotoxic activity. An annexin V- propidium iodide (PI) staining and scratch test were used to assess the induction of apoptosis and antimetastatic effects of frankincense. The frankincense extract has significant cytotoxic and apoptotic effects on breast CSLCs. Although, the breast CSLCs are more resistant to these impacts than other breast cancer cells. CONCLUSION: Our study is the first report that indicates that frankincense extract has anticancer properties in breast CSLCs. Compared to many anticancer chemicals, which have limited potential to battle cancer stem cells, frankincense is an appropriate option to combat breast CSCs.

The Effect of Exosomes Derived from Unrestricted Somatic Stem Cells on Murine Model of Sepsis.

Sepsis is a systemic infection mainly caused by bacterial infections. Despite all efforts and advances in the treatment of sepsis, it is still considered one of the leading causes of death in hospitalized patients. Today, we have to use novel therapies and one of the most important is cell-free therapy. Exosomes have been shown to contain the contents of their parent cells and that they do not generate an immune response between different individuals which makes them a good candidate for transplantation. Unrestricted somatic stem cells (USSC), also known as mesenchymal stem cell progenitors due to their high proliferative capacity and low immune response, may be a novel therapy for sepsis. In this study, the effect of USSC-derived exosomes on sepsis was investigated using a mouse model. USSCs were isolated from human cord blood and characterized by flow cytometry and multi-lineage differentiation. The exosomes were then harvested from USSCs and characterized by transmission electron microscopy, Western blotting, and dynamic light scattering. The harvested exosomes were injected into the mouse model of sepsis. Biochemical, histological, molecular, and survival studies were performed in different groups. Our observations showed that USSC-derived exosomes can reduce inflammation in septic mice. Histopathologic and biochemical findings in the sham group showed multiorgan involvement, but these changes disappeared after 7 days of exosome administration. Moreover, the expression of IRAK-1 and TRAF-6 (main adapter molecules in signaling pathways of inflammation) was decreased through negative regulation by miR-146a after 72 h of exosome administration. A 2-fold increase in the level of IL-10 and a 2-fold decrease in the levels of IL-6 and TNF-α was observed. In conclusion, we showed that direct injection of USSC-derived exosomes can be one of the important methods for the treatment of various aspects of sepsis due to their immunomodulatory properties.

Exploring the Physicochemical, Electroactive, and Biodelivery Properties of Metal Nanoparticles on Peripheral Nerve Regeneration.

Despite the advances in the regeneration/rehabilitation field of damaged tissues, the functional recovery of peripheral nerves (PNs), especially in a long gap injury, is considered a great medical challenge. Recent progress in nanomedicine has provided great hope for PN regeneration through the strategy of controlling cell behavior by metal nanoparticles individually or loaded on scaffolds/conduits. Despite the confirmed toxicity of metal nanoparticles due to long-term accumulation in nontarget tissues, they play a role in the damaged PN regeneration based on the topography modification of scaffolds/conduits, enhancing neurotrophic factor secretion, the ion flow improvement, and the regulation of electrical signals. Determining the fate of neural progenitor cells would be a major achievement in PN regeneration, which seems to be achievable by metal nanoparticles through altering cell vital approaches and controlling their functions. Therefore, in this literature, an attempt was made to provide an overview of the effective activities of metal nanoparticles on the PN regeneration, until the vital clues of the PN regeneration and how they are changed by metal nanoparticles are revealed to the researcher.

High percentage of Cancer Stem cells in metastatic locations: Upregulation of cicBIRC6 in highly metastatic breast Cancer Subline.

BACKGROUND: Metastasis is a devastating complication of breast cancer. Cancer relapse and metastasis are associated with cancer stem cells. CicBIRC6 is a circular RNA that is proposed to be involved in the stemness of stem cells. In breast cancer, metastatic tumor cells have higher stem cell properties. In the present study, we evaluate the expression of cicBIRC6 in these cells. METHODS: After the development of a syngeneic animal model of TNBC, primary breast cancer cells named 4T1T were isolated from the tumor mass. Highly metastatic tumor cells named 4T1B and 4T1L were isolated and expanded from brain metastasis lesions and lungs of cancerous mice respectively. Sphere formation ability in metastatic and primary tumor cells was evaluated separately. The quantitative real-time polymerase chain reaction was performed to analyze the expression of cicBIRC6 in primary and metastatic tumor cells. RESULTS: Our data revealed that, sphere formation ability among metastatic tumor cells was significantly higher. Surprisingly expression of cicBIRC6 was significantly upregulated in these metastatic tumor cells. In comparison with 4T1T, cicBIRC6 was upregulated 5.7 and 3.5 times in 4T1B and 4T1L respectively. CONCLUSION: These findings provided important insights regarding the molecular properties of metastatic tumor cells and can be used for designing a targeted therapeutic strategy in combat with these cells.

Down-Regulation of CXCR4 in Mesenchymal Stem Cells by Septic Serum.

Background: Sepsis is one of the main concerns of health and one of the leading causes of death in hospitals. It is essential to manage sepsis in hospitalized patients. In recent years, cell therapy has been considered as a new approach to treat sepsis. This study evaluated the effect of CXCR4 as one of the main proteins involved in the homing of mesenchymal stem cells in the sepsis serum in mice model. Methods: Mouse sepsis model was induced by injection of E.coli and biochemical analyses was done to confirm the organ failure. Mesenchymal stem cells (MSCs) derived from bone marrow were separated into sepsis and control groups. In the sepsis serum group, MSCs were treated with sepsis serum at two time points: 24 and 48 h. Quantitative RT-PCR and flow cytometry were performed to determine the mRNA expression of CXCR4 in sepsis serum group compared to control group. Also, a migration assay was done to assess the migration capacity of bone marrow MSCs during inflammation and treatment in sepsis. Results: Our result showed that treatment with sepsis serum can control migration by decrease in CXCR4 level (P ≤ 0.05) compared to control group. Moreover it was also reported that sepsis serum decreased mRNA expression of CXCR4 in MScs. Conclusions: In our study, MSCs treated with septic serum were no longer able to migrate . Probably many variables such as source, dose, injection time, and injection route of MSCs after sepsis induction in the animal models are key factors for successful cell therapy.

Mir-122 upregulation and let-7f downregulation combination: The effects on hepatic differentiation of hiPSCs on the PCL-Gel-HA nanofibrous scaffold.

Cell therapy and tissue engineering as promising candidates for the liver transplantation dilemma are of special interest. Induced pluripotent stem cells (iPSCs) are one of the best sources in this field, but their differentiation methods to hepatocytes have remained challenging. We transduced human iPSCs (hiPSCs) with miR-122 and off-let-7f (hiPSCsmiR-122 + off-let-7f ) to evaluate how they can differentiate hiPSCs to hepatocyte-like cells (HLCs) without any extrinsic growth factor. Additionally, we studied the effect of Poly ɛ-caprolactone-gelatin-hyaluronic acid (PCL-Gel-HA) nanofibrous scaffold as an extracellular matrix (ECM) simulator on differentiation improvement. Definitive endoderm markers (FOXA2 and SOX17), as well as hepatic markers (AFP, Albumin, CK18, HNF4α) expression, were significantly higher in hiPSCsmiR-122 + off-let-7f derived HLCs (hiPSCs-HLCs) compared to the control group (miR-scramble transduced hiPSCs: hiPSCsscramble ). hiPSCs-HLCs indicated hepatocyte morphological characteristics and positive immunostaining for AFP, Albumin and HNF4α. Albumin and urea secretion were significantly higher in hiPSCs-HLCs than hiPSCsscramble . Comparing these markers in the PCL-Gel-HA group with the tissue culture plate (TCP) group revealed that PCL-Gel-HA could improve differentiation towards HLCs significantly. Regarding our results, these microRNAs can be used to differentiate hiPSCs to the functional hepatocytes for disease modelling, drug screening and cell-based therapy in future studies.

Expression of osteopontin-5 splice variant in the mouse primary and metastatic breast cancer cells.

OBJECTIVE: Osteopontin (OPN) is a well-known glycoprotein involved in numerous pathobiological processes, including cancer. Despite having five splice variants for osteopontin in mice, the main focus of most studies has been on total OPN (tOPN). There are some studies on other splice variants, but the expression of osteopontin-5 (OPN5) has not been addressed in mouse cancer cells. Therefore, this study sought to evaluate OPN5 expression in mouse breast cancer cells. RESULTS: The expression of OPN5 in primary and metastatic breast cancer cells of mice was confirmed in our study. These findings provided important insights regarding the OPN alternative splicing in mice for the first time. It is concluded that, like other OPN-SVs, OPN5 probably plays an essential role in tumor progression, which requires further investigation in different tumor models.

Synergistic Anti-Cancer Activity of the Combination of 1,25-Dihydroxyvitamin D3 and Retinoic Acid in U937 Cell Line.

Background: MicroRNA is a form of non-coding RNAs that able to regulate gene expression. miR-424 is one of the members of the regulatory family, which plays an important role in the proliferation and differentiation of myeloid cells. Epigenetic changes can change the level of miR-424 under environmental factors. Therefore, the level of expression of miR-424 in U937 cells of the myeloid line was evaluated in this research under the influence of vitamin D3 (VitD3) and retinoic acid (RA). Methods: In this study, U937 cells were cultured in the presence of VitD3, and RA to evaluate cell proliferation, viability via the trypan blue exclusion test, and expression level of miR-424 by real-time PCR at specific times. Results: Cell proliferation has shown a significant decrease in the RA group versus other groups during incubation times (P < 0.05). In VitD3 group, there was a significant increase in cell proliferation after 24- and 48-hours incubation periods versus other groups. In the VitD3 and RA groups, the increase of cell proliferation caused the downregulation of miR-424. In addition, the upregulation of VitD3 group and downregulation of the RA group were significant versus the control group (P < 0.05). Discussion: We concluded that the expression level of miR-424 was critically affected in the dose- and time-dependent of RA and VitD3 treatment in the U937 cell line. Treatment with VitD3 decreased the expression of miR-424 and RA treatment increase miR-424 expression level in physiological doses.

Thrombosis in COVID-19 infection: Role of platelet activation-mediated immunity.

BACKGROUND: Thrombosis plays an important role in the Coronavrus Disease 2019 (COVID-19) infection-related complications such as acute respiratory distress syndrome and myocardial infarction. Multiple factors such as oxygen demand injuries, endothelial cells injury related to infection, and plaque formation. MAIN BODY: Platelets obtained from the patients may have severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA, showing that the increased activation potential recommends platelet can be hyper-activated in severely ill SARS-CoV-2 cases. Platelets contain multiple receptors that interact with specific ligands. Pathogen's receptors such as Toll-like receptors (TLRs), NOD-like receptor, C-type lectin receptor family, glycoprotein (GP) such as GPαIIbß3 and GPIbα which allow pathogens to interact with platelets. Platelet TLRs and NOD2 are involved in platelet activation and thrombosis. Accordingly, TLRs are critical receptors that could recognize various endogenous damage-associated molecular patterns and exogenous pathogen-associated molecular patterns (PAMPs). TLRs are considered as important components in the activation of innate immunity response against pathogenic and non-pathogenic components like damaged tissues. TLRs-1,-2,-4,-6,-7 expression on or within platelets has been reported previously. Various PAMPs were indicated to be capable of binding to platelet-TLRs and inducing both the activation and promotion of downstream proinflammatory signaling cascade. CONCLUSION: It is possible that the increased TLRs expression and TLR-mediated platelets activation during COVID-19 may enhance vascular and coronary thrombosis. It may be hypothesized using TLRs antagonist and monoclonal antibody against P-selectin, as the marker of leukocyte recruitment and platelet activation, besides viral therapy provide therapeutic advances in fighting against the thrombosis related complications in COVID-19.

Evaluation of Acellular Dermal Matrix (ADM) as a Scaffold for Adipose-Derived Stem Cell Transfer in the Rat Model.

BACKGROUND: This study was designed for the evaluation of Acellular Dermal Matrix (ADM) as a scaffold for adipose-derived stem cell transferring in the rat model. METHODS: This experimental study was done in the Burn Research Center of Iran University of Medical Sciences and Bonyakhteh Research Center, Tehran, Iran according to the standards of laboratory animals. Overall, 26 healthy Sprague-Dawley rats were used. Two of them were used to prepare ADM. In group one, the first wound on each, rat was spread with the mixture of fibrin gel and autologous stem cell. Only the stem cells combined with fibrinogen were spread on the other wound. In group two, the first wound on each rat was covered only with ADM, and the second wound was covered with gauze Vaseline. To perform sampling we used observation and photography at 7-30 days. Overall, 48 samples were taken of all the rats using skin punch biopsy on the 30th day for histopathology evaluation. RESULTS: There were significant differences in each group; however, the difference between different groups on days was not significant. In pathology, epithelialization, vascularization, the amount of collagen, collagen arrangement, the number of fibroblasts, and inflammation indices were investigated. The total score in each group was used for analysis. In statistical analysis, there was no pathology score difference among groups. CONCLUSION: Using stem cells with or without ADM could not enhance the process of wound healing or improve pathology indices.

Induced pluripotent stem cell technology: trends in molecular biology, from genetics to epigenetics.

Induced pluripotent stem cell (iPSC) technology, based on autologous cells' reprogramming to the embryonic state, is a new approach in regenerative medicine. Current advances in iPSC technology have opened up new avenues for multiple applications, from basic research to clinical therapy. Thus, conducting iPSC trials have attracted increasing attention and requires an extensive understanding of the molecular basis of iPSCs. Since iPSC reprogramming is based on the methods inducing the expression of specific genes involved in pluripotency states, it can be concluded that iPSC reprogramming is strongly influenced by epigenetics. In this study, we reviewed the molecular basis of reprogramming, including the reprogramming factors (OCT4, SOX2, KLF4, c-MYC, NANOG, ESRRB, LIN28 as well as their regulatory networks), applied vectors (retroviral vectors, adenoviral vectors, Sendaiviral vectors, episomal plasmids, piggyBac, simple vectors, etc.) and epigenetic modifications (miRNAs, histones and DNA methylation states) to provide a comprehensive guide for reprogramming studies.