The effect of thyme essential oil and endothelial progenitor stem cells on lipopolysaccharide-induced sepsis in C57BL/6 mice.

Sepsis is a potentially fatal syndrome related to severe systemic inflammation developed by infection. Despite different antimicrobial therapies, morbidity and mortality rates remain high. Herbs along with cell therapy have been introduced as a promising option to improve the symptoms of sepsis. The present study aimed to evaluate the therapeutic effect of simultaneous administration of thyme essential oil (TEO) and endothelial progenitor stem cells (EPCs) on lipopolysaccharide (LPS)-induced sepsis in C57BL/6 mice. Sepsis was induced in C57Bl/6J mice by intraperitoneal injection of LPS, followed 2 h later by an intravenous injection of EPCs or oral administration of TEO or simultaneous administration of TEO and EPCs. After 10 days, the complete blood cell, renal and liver factors, serum levels of inflammatory cytokines, and angiogenic factors were measured. Simultaneous treatment with EPCs and TEO significantly increased the survival of mice with sepsis and modulated the inflammatory response by reducing the serum levels of pro-inflammatory cytokines. Moreover, this treatment significantly reduced the level of white blood cells and neutrophils and increased the number of red blood cells, the percentage of hematocrit, and hemoglobin. The combination of TEO with EPCs decreased organ injuries and was assessed by lower levels of the liver enzymes alanine aminotransferase and aspartate aminotransferase compared to the sepsis group. Administration of EPCs and TEO also significantly improved angiogenic factors, lung function, and toll-like receptor 4 expression. EPCs in combination with TEO increase survival in the LPS-induced sepsis mice model by acting on several targets. Thus, the combination of TEO with EPCs can be a feasible approach for the future clinical treatment and control of sepsis.

Safety and potency of BIV1-CovIran inactivated vaccine candidate for SARS-CoV-2: A preclinical study.

The development of effective and safe COVID-19 vaccines is a major move forward in our global effort to control the SARS-CoV-2 pandemic. The aims of this study were (1) to develop an inactivated whole-virus SARS-CoV-2 candidate vaccine named BIV1-CovIran and (2) to determine the safety and potency of BIV1-CovIran inactivated vaccine candidate against SARS-CoV-2. Infectious virus was isolated from nasopharyngeal swab specimen and propagated in Vero cells with clear cytopathic effects in a biosafety level-3 facility using the World Health Organization's laboratory biosafety guidance related to COVID-19. After characterisation of viral seed stocks, the virus working seed was scaled-up in Vero cells. After chemical inactivation and purification, it was formulated with alum adjuvant. Finally, different animal species were used to determine the toxicity and immunogenicity of the vaccine candidate. The study showed the safety profile in studied animals including guinea pig, rabbit, mice and monkeys. Immunisation at two different doses (3 or 5 µg per dose) elicited a high level of SARS-CoV-2 specific and neutralising antibodies in mice, rabbits and nonhuman primates. Rhesus macaques were immunised with the two-dose schedule of 5 or 3 µg of the BIV1-CovIran vaccine and showed highly efficient protection against 104 TCID50 of SARS-CoV-2 intratracheal challenge compared with the control group. These results highlight the BIV1-CovIran vaccine as a potential candidate to induce a strong and potent immune response that may be a promising and feasible vaccine to protect against SARS-CoV-2 infection.

Development of a recombinant anti-VEGFR2-EPCAM bispecific antibody to improve antiangiogenic efficiency.

Tumor progression and metastasis, especially in invasive cancers (such as triple-negative breast cancer [TNBC]), depend on angiogenesis, in which vascular epithelial growth factor (VEGF)/vascular epithelial growth factor receptor [1] has a decisive role, followed by the metastatic spread of cancer cells. Although some studies have shown that anti-VEGFR2/VEGF monoclonal antibodies demonstrated favorable results in the clinic, this approach is not efficient, and further investigations are needed to improve the quality of cancer treatment. Besides, the increased expression of epithelial cell adhesion molecule (EpCAM) in various cancers, for instance, invasive breast cancer, contributes to angiogenesis, facilitating the migration of tumor cells to other parts of the body. Thus, the main goal of our study was to target either VEGFR2 or EpCAM as pivotal players in the progression of angiogenesis in breast cancer. Regarding cancer therapy, the production of bispecific antibodies is easier and more cost-effective compared to monoclonal antibodies, targeting more than one antigen or receptor; for this reason, we produced a recombinant antibody to target cells expressing EpCAM and VEGFR2 via a bispecific antibody to decrease the proliferation and metastasis of tumor cells. Following the cloning and expression of our desired anti-VEGFR2/EPCAM sequence in E. coli, the accuracy of the expression was confirmed by Western blot analysis, and its binding activities to VEGFR2 and EPCAM on MDA-MB-231 and MCF-7 cell lines were respectively indicated by flow cytometry. Then, its anti-proliferative potential was indicated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and apoptosis assay to evaluate inhibitory effects of the antibody on tumor cells. Subsequently, the data indicated that migration, invasion, and angiogenesis were inhibited in breast cancer cell lines via the bispecific antibody. Furthermore, cytokine analysis indicated that the bispecific antibody could moderate interleukin 8 (IL-8) and IL-6 as key mediators in angiogenesis progression in breast cancer. Thus, our bispecific antibody could be considered as a promising candidate tool to decrease angiogenesis in TNBC.

Macrophage polarization by MSC-derived CXCL12 determines tumor growth.

BACKGROUND: Phenotypic and functional heterogeneity of macrophages is known to be the main reason for their ability to regulate inflammation and promote tumorigenesis. Mesenchymal stem cells (MSCs) are one of the principal cells commonly found in the tumor stromal niche, with capability of macrophage phenotypic switching. The objective of this study was to evaluate the role of C-X-C motif chemokine ligand 12 (CXCL12) produced by marrow-derived MSCs in the phenotypic and functional pattern of bone marrow-derived macrophages (BMDMs). METHODS: First, the CRISPR/Cas9 system was used for the CXCL12 gene knock-out in MSCs. Then, coculture systems were used to investigate the role of MSCsCXCL12-/- and MSCsCXCL12+/+ in determination of macrophage phenotype. To further analyze the role of the MSC-derived CXCL12 niche, cocultures of 4T1 mammary tumor cells and macrophages primed with MSCsCXCL12-/- or MSCsCXCL12+/+ as well as in-vivo limiting dilution assays were performed. RESULTS: Our results revealed that the expression of IL-4, IL-10, TGF-ß and CD206 as M2 markers was significantly increased in macrophages co-cultured with MSCsCXCL12+/+ , whereas the expression of IL-6, TNF-α and iNOS was conversely decreased. The number and size of multicellular tumor spheroids were remarkably higher when 4T1 cells were cocultured with MSCCXCL12+/+-induced M2 macrophages. We also found that the occurrence of tumors was significantly higher in coinjection of 4T1 cells with MSCCXCL12+/+-primed macrophages. Tumor initiating cells were significantly decreased after coinjection of 4T1 cells with macrophages pretreated with MSCsCXCL12-/-. CONCLUSIONS: In conclusion, our findings shed new light on the role of MSC-derived CXCL12 in macrophage phenotypic switching to M2, affecting their function in tumorigenesis.

Impairment of endothelial progenitor cells function in patient with mustard gas intoxication.

Background: Sulfur mustard (SM), also known as mustard gas, was first widely used in the Iraq-Iran. After SM exposure, the most prominent clinical signs are the development of extensive non-healing skin wounds and pulmonary signs, persisting over long time. Since the most frequent complications in SM-intoxicated patients are respiratory and dermatologic lesions, and with respect to the important role of endothelial progenitor cells (EPCs) in the pathophysiology of these lesion, we conducted this study to recognize the potential effects of SM on biological features of EPCs in patients exposed with this gas.Methods: In this study, 30 patients with the history of SM exposure during the Iran-Iraq war (1984-1988), 27 patients with pulmonary signs with no history of SM exposure and 20 healthy participants were included. Cell population and function of EPCs were assessed 4 years post-exposure. For this purpose, circulating EPCs (cEPCs) were harvested and cultivated, then the biological features of these cells, including migratory, proliferative, and tubulogenic activities were analyzed. We also measured serum antioxidants levels and mRNA levels of some proangiogenic factors in EPCs from SM-intoxicated patients.Results: Our results showed lesser number of cEPCs in patients exposed with SM, which was associated with decreased proliferative, migratory, and tubulogenic activity of these cells. Also, we found the lesser serum activity of SOD, GPX and MDA in the SM group than in the healthy control group.Conclusions: SM exposure resulted in decreased proliferation and migration of EPCs, which was associated with decreased tubule formation and angiogenic factors.

Distinct Tie2 tyrosine phosphorylation sites dictate phenotypic switching in endothelial progenitor cells.

Angiogenesis is a regulated process involving the proliferation, migration, and remodeling of different cell types particularly mature endothelial and their progenitor cells, nominated as endothelial progenitor cells (EPCs). Tie2/Tek is a tyrosine kinase receptor expressed by endothelial cells that induces signal transduction pathways involved in endothelial biology. To address the potential importance of the various tyrosine residues of Tie2 in EPC development, we generated a series of Tie2 tyrosine mutated (Y1106F, Y1100F, and Y1111F) EPCs and then assess the biological features of these cells. Clonogenic, tubulogenic, proliferative, migratory, and functional properties of these cells were analyzed. Next, GFP-positive EPCs containing Tie2 tyrosine mutations were systemically transplanted into sublethaly irradiated mice to analyze the potency of these cells for marrow reconstitution. We found that mutation in the Tie2 tyrosine 1106 residue directed EPCs toward a mature endothelial phenotype, which was associated with augmented tubulogenic and migratory properties, and increased phosphorylation of the active site (tyrosine 992) as well as increased vascular perfusion in the in vivo Matrigel plug assay. Moreover, transplantation of 1106 Tie2 mutant EPCs failed to reconstitute the bone marrow after myeloablation, whereas transplantation of EPCs with the 1100 or 1111 Tie2 tyrosine mutation resulted in bone marrow engraftment, leading to improved survival of recipient mice. Our findings demonstrate that the tyrosine 1106 residue in Tie2 plays a key role to maintain the stemness features of EPCs.

Human unrestricted somatic stem cells ameliorate sepsis-related acute lung injury in mice.

BACKGROUND AIMS: Sepsis and related disorders, especially acute lung injury (ALI), are the most challenging life-threatening diseases in the hospital intensive care unit. Complex pathophysiology, unbalanced immune condition, and high rate of mortality complicate the treatment of sepsis. Recently, cell therapy has been introduced as a promising option to recover the sepsis symptoms. The aim of this study was to investigate the therapeutic potential of human unrestricted somatic stem cells (USSCs) isolated from human umbilical cord blood in the mouse model of ALI. USSCs significantly enhanced the survival rate of mice suffering from ALI and suppressed concentrations of proinflammatory mediators TNF-α, and interleukin (IL)-6, and the level of anti-inflammatory cytokine IL-10. ALI mice injected by USSCs showed notable reduction in lung and liver injury, pulmonary edema, and hepatic enzymes, compared with the control group. These results determined the in vivo immunomodulatory effect of USSCs for recovery of immune balance and reduction of tissue injury in the mouse model of ALI. Therefore, USSCs can be a suitable therapeutic approach to manage sepsis disease through the anti-inflammatory potential.

Improved angiogenic activity of endothelial progenitor cell in diabetic patients treated with insulin plus metformin.

Type 2 diabetes (T2DM) is associated with an increased vascular disease. Moreover, endothelial progenitor cell (EPC) function is impaired in diabetic patients. Decreased EPC number plays a critical role in reduced endothelial repair and development of the vascular disorder. To determine the effect of metformin and insulin plus metformin on functional activity of EPCs, 130 participants were divided into three groups (group 1: healthy control; group 2: metformin; group 3: insulin plus metformin). The concentration of EPCs in the circulation was first quantified. Thereafter, circulating EPCs (cEPCs) were harvested and the biological features of these cells including proliferative, clonogenicity, tubulogenic, and migratory properties were analyzed after expansion. The serum protein levels of some proangiogenic factors were also measured. Our results showed greater numbers of cEPCs in control and in diabetic patients treated with insulin plus metformin than in metformin-treated patients. Insulin plus metformin therapy was associated with augmented proliferative, clonogenicity, migratory, and tubulogenic activity of cEPCs in patients with T2DM. Increased serum concentrations of angiogenic factors were also observed in patients treated with insulin plus metformin. Western blot analysis showed increased protein levels of pTie-2/Tie2 and Pakt/AKT in cEPCs harvested from T2DM, treated with insulin metformin plus. This study showed that treatment with insulin plus metformin in diabetic patients is associated with increased mobilization of EPCs into the circulation, with potential beneficial effect in vascular protection in diabetic patients.

Increased circulation mobilization of endothelial progenitor cells in preterm infants with retinopathy of prematurity.

Retinopathy of prematurity (ROP) is a result of increased pathological neoangiogenesis of the retina in preterm infants. Cells responsible for the pathogenesis of ROP are unclear, but some evidence indicates that bone marrow derived cells are involved in this disorder. Endothelial progenitor cells (EPCs), play a role in angiogenesis in response to tissue ischemia or endothelial damage. In this study, the number of cEPCs in preterm infants with ROP was determined to identify whether the circulation mobilization of EPCs is associated with ROP. We evaluated 99 participants in this study: 22 preterm infants with ROP, 35 preterm infants without ROP, and 42 full-term infants. The release of EPCs in the circulation was first quantified. Thereafter, cEPCs were harvested and cultivated, then the biological features of these cells including migratory, proliferative, and tubulogenic activities were analyzed. The mRNA levels of some proangiogenic factors were also measured in preterm infants. Our results showed greater numbers of cEPCs in infants with ROP, which was associated with increased serum concentrations of angiogenic factors and with augmented proliferative, migratory, and tubulogenic activity of these cells. Western blotting showed increased protein levels of VEGF and HIF-α in cEPCs harvested from ROP infants. This study showed that ROP in preterm infants is associated with increased mobilization of EPCs into the circulation. Therefore, increased cEPCs along with elevated levels of angiogenic factors and tubulogenesis suggest that these cells may play a role in the development and progression of ROP.

Hyperbilirubinemia-induced pro-angiogenic activity of infantile endothelial progenitor cells.

OBJECTIVES: Bilirubin, a by-product of heme degradation, is suggested to have a role for vascular protection. There is increasing evidence that bilirubin may directly affect the function and secretory activity of endothelial cells. In this study, potential effect of hyperbilirubinemia on biological features of circulation endothelial progenitor cells (cEPCs) isolated from infants was investigated. METHODS: Circulation concentration, differentiation and migratory activity of cEPCs isolated from infants with (n = 111) or without (n = 73) hyperbilirubinemia were analyzed. Then, the potential beneficial effect of conditioned medium of cEPCs from infants with or without hyperbilirubinemia was examined on experimental mouse wounds. RESULTS: Our results revealed significantly higher percentages of cEPCs in infants with hyperbilirubinemia. Cell proliferation, and migratory properties of cEPCs isolated and expanded from infants with hyperbilirubinemia were significantly improved. Also, the conditioned medium of cEPCs from hyperbilirubinemic infants possessed a superior beneficial effect on wound healing, which was associated with increased protein levels of VEGF, IL-10, and Pho-ERK/ERK, and decreased TNF-α in the wound tissues. CONCLUSIONS: Our results showed that hyperbilirubinemia can activate migration, proliferating and angiogenic properties of cEPCs. Hyperbilirubinemia can promote the proangiogenic secretory activity of cEPCs, thereby resulting in enhancement of their regenerative wound healing properties.

Carvacrol promotes angiogenic paracrine potential and endothelial differentiation of human mesenchymal stem cells at low concentrations.

OBJECTIVES: Phenolic monoterpene compound, named Carvacrol, has been found to exert different biological outcomes. It has been accepted that the angiogenic activity of human mesenchymal stem cells was crucial in the pursuit of appropriate regeneration. In the current experiment, we investigated the contribution of Carvacrol on the angiogenic behavior of primary human mesenchymal stem cells. METHODS: Mesenchymal stem cells were exposed to Carvacrol in a dose ranging from 25 to 200µM for 48h. We measured cell survival rate by MTT assay and migration rate by a scratch test. The oxidative status was monitored by measuring SOD, GPx activity. The endothelial differentiation was studied by evaluating the level of VE-cadherin and vWF by real-time PCR and ELISA analyses. The content of VEGF and tubulogenesis behavior was monitored in vitro. We also conducted Matrigel plug in vivo CAM assay to assess the angiogenic potential of conditioned media from human mesenchymal stem cells after exposure to Carvacrol. RESULTS: Carvacrol was able to increase mesenchymal stem cell survival and migration rate (p<0.05). An increased activity of SOD was obtained while GPx activity unchanged or reduced. We confirmed the endothelial differentiation of stem cells by detecting vWF and VE-cadherin expression (p<0.05). The VEGF expression was increased and mesenchymal stem cells conditioned media improved angiogenesis tube formation in vitro (p<0.05). Moreover, histological analysis revealed an enhanced microvascular density at the site of Matrigel plug in CAM assay. CONCLUSIONS: Our data shed lights on the possibility of a Carvacrol to induce angiogenesis in human mesenchymal stem cells by modulating cell differentiation and paracrine angiogenic response.

Circulating endothelial progenitor cells in pregnant women with premature rupture of membranes: potential association with placental disorders.

The frequency of preterm labour has risen over the last few years. Plasma oestrogen concentrations differ between patients who deliver before term and those who deliver at term. Oestrogen can influence the kinetics of circulating endothelial progenitor cells (cEPCs). Here, we attempted to identify the potential association of cEPCs with the incidence of complications typical of prematurity. The study groups consisted of 60 pregnant women with premature rupture of membranes (PROM; less than 37 weeks) and 50 term pregnant women (more than 38 weeks). cEPCs were isolated from term pregnant women and pregnant women with PROM and then migratory, proliferative, tubulogenic and functional properties of these cells along with serum secretion of important EPC chemotactic cytokines were analysed. In addition, the effect of 17ß-oestradiol on biological features of cEPCs harvested from pregnant women was investigated. Our results showed that an increased concentration of oestrogen in women with PROM was associated with increased numbers of cEPCs, with these cells having increased oestrogen receptor α expression together with augmented proliferative, migratory and colony-formation properties. 17ß-oestradiol induced proliferation, migration and angiogenic secretory activity of cEPCs from pregnant women. Overall, circulation mobilisation of EPCs in pregnant women may be associated with placental disorders.

ß3-Adrenergic Regulation of EPC Features Through Manipulation of the Bone Marrow MSC Niche.

Mesenchymal stem cells (MSCs) reside in a specific niche in the bone marrow, however, biological features of this niche are still not fully understood. Given the interactions of MSCs with endothelial cells in different tissues, bone marrow MSC niche may influence the biological features of endothelial progenitor cells (EPCs). To understand the role of the sympathetic nervous system in regulation of the MSC niche, we examined whether the manipulation of the MSC niche via ß3-adrenergic signals will affect EPC features. A selective ß3 agonist (BRL37344) or a ß3 antagonist (SR59230A) was administered in mice for 2 weeks to determine the potential effects of these regimens on the population of CD133+ stem cells in the bone marrow. Then, bone marrow-derived MSCs and EPCs were harvested and expanded from the mice to examine the effect of changes in the MSC niche on EPC features. Improved MSC colony forming potency with increased bone marrow stromal cell-derived factor 1 (SDF-1) (also known as C-X-C motif chemokine 12 [CXCL12]) expression was shown as a result of intensification of the bone marrow adrenergic signals through BRL37344 injection. On the other hand, the blockage of these signals limited the expression level of SDF-1 and resulted in bone marrow enrichment of CD133+ cells. Manipulation of the MSC niche and decreased SDF-1 expression via SR59230A injection also prompted EPCs to form more colonies with augmented proliferation and differentiation capacity. Overall, our results indicate that the ß3-adrenergic signals regulate the MSC niche, thereby resulting in modulation of EPC biological features. J. Cell. Biochem. 118: 4753-4761, 2017. © 2017 Wiley Periodicals, Inc.

The Improvement of Respiratory Performance After Phototherapy-Induced EPC Mobilization in Preterm Infants With RDS.

Many infants who develop bronchopulmonary dysplasia (BPD) are born with serious respiratory distress syndrome (RDS), which is associated with impaired vascular and alveolar growth. RDS is a breathing disorder that mostly affects preterm infants and occurs in infants whose lungs have not yet been fully developed. The use of surfactant in RDS treatment does not necessarily prevent BPD. Endothelial progenitor cells (EPCs) may contribute to lung angiogenesis for the prevention and treatment of BPD. The aim of this study was to evaluate the therapeutic efficacy of phototherapy for EPC release in preterm infants born with RDS. Seventy-five RDS preterm infants were divided into two groups: RDS with phototherapy and RDS without phototherapy. Respiratory indices were recorded for each patient. Circulating EPCs were isolated before and after phototherapy and colony forming efficiency, chemotactic, tubulogenic, proliferative, and functional properties of these cells were analyzed. Our results showed that phototherapy increased the release of EPCs into the circulation in RDS preterm infants, with augmentation of cell proliferation, tubulogenic, chemotactic, and proliferative properties of EPCs. Phototherapy-induced EPC release was associated with improved lung function as was recorded by significantly decrease in continuous positive airway pressure (CPAP) days, CPAP plus ventilator days, and PCO2 along with a significant increase in PO2 and PaO2 /FiO2 , resulting in markedly decreased rate of BPD occurrence in preterm infants with RDS. Overall, phototherapy is touted as a promising modality for the amelioration of respiratory performance and prohibition of BPD occurrence in RDS preterm infants. J. Cell. Biochem. 118: 594-604, 2017. © 2016 Wiley Periodicals, Inc.

Circulation Enrichment of Functional Endothelial Progenitor Cells by Infantile Phototherapy.

Phototherapy is the most common therapy used for severe jaundice. There is increasing evidence that phototherapy can directly affect the expression and function of cell surface receptors including adhesion molecules, cytokines, and growth factor receptors. In this study, the effect of two infantile phototherapy regimens, including single and intensive phototherapy was investigated on biological features of circulation endothelial progenitor cells (cEPCs), as well as on serum secretion of two important chemotactic cytokines, SDF-1 and VEGF. Sixty infants diagnosed with severe hyperbilirubinemia and exposed to phototherapy were enrolled in this study. cEPCs were isolated before and after phototherapy and then migratory, proliferative, tubulogenic, and functional properties of these cells were analyzed. Our results revealed that intensive phototherapy markedly increased the release of EPCs into the circulation, and augmented the serum concentrations of both SDF-1 and VEGF cytokines. Cell proliferation, tubulogenic, and migratory properties of cEPCs isolated and expanded from infants with intensive phototherapy were significantly improved. cEPCs from infants with intensive phototherapy also showed greater levels of acetylated low-density lipoprotein and lectin binding. Overall, our results showed that the intensive phototherapy regimen can mobilize functional EPCs into the circulation through up-regulation of serum levels of VEGF and SDF-1, indicating phototherapy as an effective modality for improvement of stem cell mobilization in the therapeutic regenerative medicine. J. Cell. Biochem. 118: 330-340, 2017. © 2016 Wiley Periodicals, Inc.

Endothelial Progenitor Cell Mobilization in Preterm Infants With Sepsis Is Associated With Improved Survival.

Microvascular dysfunction plays a key role in the pathology of sepsis, leading to multi-organ failure, and death. Circulating endothelial progenitor cells (cEPCs) are critically involved in the maintenance of the vascular homeostasis in both physiological and pathological contexts. In this study, concentration of cEPCs in preterm infants with sepsis was determined to recognize whether the EPC mobilization would affect the clinical outcome of infantile sepsis. One hundred and thirty-three preterm infants (81 with sepsis and 52 without sepsis) were enrolled in this study. The release of EPCs in circulation was first quantified. Thereafter, these cells were cultivated and biological features of these cells such as, proliferation and colony forming efficiency were analyzed. The levels of chemoattractant cytokines were also measured in infants. In mouse models of sepsis, effects of VEGF and SDF-1 as well as anti-VEGF and anti-SDF-1 were evaluated in order to shed light upon the role which the EPC mobilization plays in the overall survival of septic animals. Circulating EPCs were significantly higher in preterm infants with sepsis than in the non-sepsis group. Serum levels of VEGF, SDF-1, and Angiopoietin-2 were also higher in preterm infants with sepsis than in control non-sepsis. In the animal experiments, injection of VEGF and SDF-1 prompted the mobilization of EPCs, leading to an improvement in survival whereas injection of anti-VEGF and anti-SDF-1 was associated with significant deterioration of survival. Overall, our results demonstrated the beneficial effects of EPC release in preterm infants with sepsis, with increased mobilization of these cells was associated with improved survival. J. Cell. Biochem. 118: 3299-3307, 2017. © 2017 Wiley Periodicals, Inc.

ECM-Dependence of Endothelial Progenitor Cell Features.

Preserving self-renewal, multipotent capacity, and large-scale expansion of highly functional progenitor cells, including endothelial progenitor cells (EPCs), is a controversial issue. These current limitations, therefore, raise the need of developing promising in vitro conditions for prolonged expansion of EPCs without loss of their stemness feature. In the current study, the possible role of three different natural extracellular substrates, including collagen, gelatin, and fibronectin, on multiple parameters of EPCs such as cell morphology, phenotype, clonogenic, and vasculogenic properties was scrutinized. Next, EPCs from GFP-positive mice were pre-expanded on each of these ECM substrates and then systemically transplanted into sublethaly irradiated mice to analyze the potency of these cells for marrow reconstitution. Our results revealed considerable promise for fibronectin for EPC expansion with maintenance of stemness characteristics, whereas gelatin and collagen matrices directed the cells toward a mature endothelial phenotype. Transplantation of EPCs pre-expanded on fibronectin resulted in widespread distribution and appropriate engraftment to various tissues with habitation in close association with the microvasculature. In addition, fibronectin pre-expanded cells were gradually enriched in the bone marrow after transplantation, resulting in marrow repopulation and hematologic recovery, leading to improved survival of recipient mice whereas gelatin- and collagen-expanded cells failed to reconstitute the bone marrow. This study demonstrated that, cell characteristics of in vitro expanded EPCs are determined by the subjacent matrix. Fibronectin-expanded EPCs are heralded as a source of great promise for bone marrow reconstitution and neo-angiogenesis in therapeutic bone marrow transplantation. J. Cell. Biochem. 117: 1934-1946, 2016. © 2016 Wiley Periodicals, Inc.

Endothelial juxtaposition of distinct adult stem cells activates angiogenesis signaling molecules in endothelial cells.

Efficacy of therapeutic angiogenesis needs a comprehensive understanding of endothelial cell (EC) function and biological factors and cells that interplay with ECs. Stem cells are considered the key components of pro- and anti-angiogenic milieu in a wide variety of physiopathological states, and interactions of EC-stem cells have been the subject of controversy in recent years. In this study, the potential effects of three tissue-specific adult stem cells, namely rat marrow-derived mesenchymal stem cells (rBMSCs), rat adipose-derived stem cells (rADSCs) and rat muscle-derived satellite cells (rSCs), on the endothelial activation of key angiogenic signaling molecules, including VEGF, Ang-2, VEGFR-2, Tie-2, and Tie2-pho, were investigated. Human umbilical vein endothelial cells (HUVECs) and rat lung microvascular endothelial cells (RLMECs) were cocultured with the stem cells or incubated with the stem cell-derived conditioned media on Matrigel. Following HUVEC-stem cell coculture, CD31-positive ECs were flow sorted and subjected to western blotting to analyze potential changes in the expression of the pro-angiogenic signaling molecules. Elongation and co-alignment of the stem cells were seen along the EC tubes in the EC-stem cell cocultures on Matrigel, with cell-to-cell dye communication in the EC-rBMSC cocultures. Moreover, rBMSCs and rADSCs significantly improved endothelial tubulogenesis in both juxtacrine and paracrine manners. These two latter stem cells dynamically up-regulated VEGF, Ang-2, VREGR-2, and Tie-2 but down-regulated Tie2-pho and the Tie2-pho/Tie-2 ratio in HUVECs. Induction of pro-angiogenic signaling in ECs by marrow- and adipose-derived MSCs further indicates the significance of stem cell milieu in angiogenesis dynamics.

Cell therapy in patients with COVID-19 using Wharton's jelly mesenchymal stem cells: a phase 1 clinical trial.

BACKGROUND: Mesenchymal stem cells (MSCs) have received particular attention because of their ability to modulate the immune system and inhibit inflammation caused by cytokine storms due to SARS-CoV-2. New alternative therapies may reduce mortality rates in patients with COVID19. This study aimed to assess the safety and efficacy of injecting intravenous Wharton's jelly-derived MSCs in patients with COVID-19 as a treatment. METHODS: In this study, five patients with severe COVID-19 were treated with Wharton's jelly-derived mesenchymal stem cells (150 × 106 cells per injection). These patients were subject to three intravenous injections 3 days apart, and monitoring was done on days 0, 3, 6, and 14 in routine tests, inflammatory cytokines, and flow cytometry of CD4 and CD8 markers. A lung CT scan was performed on base and days 14 and 28. In addition, IgM and IgG antibodies against SARS-CoV-2 were measured before and after treatment. RESULTS: The results showed that IL-10 and SDF-1 increased after cell therapy, but VEGF, TGF-ß, IFN-γ, IL-6, and TNFα decreased. Routine hematology tests, myocardial enzyme tests, biochemical tests, and inflammation tests were performed for all patients before and after cell therapy on base and days 3, 6, and 14, which indicated the improvement of test results over time. COVID-19 antibody tests rose in 14 days after WJ-MSC injection. The total score of zonal involvement in both lungs was improved. CONCLUSIONS: In patients, the trend of tests was generally improving, and we experienced a reduction in inflammation. No serious complications were observed in patients except the headache in one of them, which was resolved without medication. In this study, we found that patients with severe COVID-19 in the inflammatory phase respond better to cell therapy. More extensive clinical trials should be performed in this regard. TRIAL REGISTRATION: IRCT, IRCT20190717044241N2 . Registered April 22, 2020.