The Involvement of Canonical NFκB Pathway in Megakaryocyte Differentiation Induction by Nanocurcumin.

Background: Megakaryopoiesis is characterized by progressive polyploidization and the expression of megakaryocytic markers. Numerous transcription factors and physiological signaling pathways regulate this phenomenon. Megakaryocyte differentiation induction in the K562 cell line and hematopoietic stem cells via nanocurcumin drug has been identified in our previous study. K562 cells are typical Chronic Myelogenous Leukemia (CML) cells that are resistant to apoptosis and express the bcr-abl fusion gene. These cells have the potential to differentiate into erythrocytes and megakaryocytes. Curcumin is well known as a component with strong potential to alter NFκB activity in various cells. NFκB pathway regulates various genes such as apoptotic and immune response genes. The current study attempted to evaluate the possible role of nanocurcumin in NFκB pathway regulation during the megakaryopoiesis process in the K562 cell line. Materials and Methods: Megakaryocyte markers expression and phenotype alteration of nanocurcumin-treated K562 cells have been detected by flow cytometry and microscopy imaging. The nuclear level of the RelA (p65) subunit of NFκB was determined by western blot test in K562 cells during megakaryopoiesis induction via nanocurcumin treatment at different times. The expression of NFκB target genes including c-MYC, BAX, and NQO1 was also analyzed in nanocurcumin-treated K562 cells by quantitative RT-PCR assay at different times. Results: The study has shown that nanocurcumin causes an increase in NFκB activity transiently during megakaryocyte differentiation, followed by a change in the expression of c-MYC, BAX, and NQO1 target genes. Conclusion: The NFκB pathway can be considered a new pathway for inducing megakaryocyte differentiation by nanocurcumin in vitro and in vivo megakaryopoiesis experiments.

CML derived exosomes promote tumor favorable functional performance in T cells.

BACKGROUND: Leukemic cells facilitate the creation of the tumor-favorable microenvironment in the bone marrow niche using their secreted factors. There are not comprehensive details about immunosuppressive properties of chronic myelogenous leukemia-derived exosomes in the bone marrow stromal and immune compartment. We explained here that K562-derived exosomes could affect the gene expression, cytokine secretion, nitric oxide (NO) production, and redox potential of human primary cord blood-derived T cells (CB T cells). METHODS: Human primary cord blood-derived T cells were treated with K562-derived exosomes. We evaluated the expression variation of some critical genes activated in suppressor T cells. The alterations of some inflammatory and anti-inflammatory cytokines levels were assessed using ELISA assay and real-time PCR. Finally, NO production and intracellular ROS level in CB T cells were evaluated using Greiss assay and flow cytometry, respectively. RESULTS: Our results showed the over-expression of the genes involved in inhibitory T cells, including NQO1, PD1, and FoxP3. In contrast, genes involved in T cell activation such as CD3d and NFATc3 have been reduced significantly. Also, the expression of interleukin 10 (IL-10) and interleukin 6 (IL-6) mRNAs were significantly up-regulated in these cells upon exosome treatment. In addition, secretion of the interleukin 10, interleukin 6, and interleukin 17 (IL-17) proteins increased in T cells exposed to K562-derived exosomes. Finally, K562-derived exosomes induce significant changes in the NO production and intracellular ROS levels in CB T cells. CONCLUSIONS: These results demonstrate that K562-derived exosomes stimulate the immunosuppressive properties in CB-derived T cells by inducing anti-inflammatory cytokines such as IL-10, reducting ROS levels, and arising of NO synthesis in these cells. Moreover, considering the elevation of FOXP3, IL-6, and IL-17 levels in these cells, exosomes secreted by CML cells may induce the fates of T cells toward tumor favorable T cells instead of conventional activated T cells.

Evaluation of the confidential unit exclusion on Iranian blood donors: An 11-year experience.

BACKGROUND: Confidential unit exclusion (CUE) was recommended by the Food and Drug Administration to permit blood donors confidentially exclude their donation for transfusion. However, its effectiveness as a safety measure to the blood supply is debated. AIMS: We, therefore, evaluated its benefit in identifying donors at risk of transmitting transfusion-transmissible infections (TTIs) and increasing blood safety in our population. SETTINGS AND DESIGN: This was a cross-sectional and retrospective study. The study was performed at the South Khorasan Blood Transfusion Center. MATERIALS AND METHODS: In this descriptive and retrospective study, data of CUE use and data of confirmed positive TTI markers were analyzed for the study period 2006-2016. STATISTICAL ANALYSIS: Data were analyzed using SPSS software version 16. RESULTS: Out of 165,267 donations, the CUE option was selected by 493 (0.3%) donors, most frequently by first-time blood donors, by men, by donors with <12 years schooling, and by 18-24-year-old donors. The data revealed that donations from CUE donors had no higher infection rates. Moreover, CUE showed low sensitivity (0.6%) and low positive predictive value (0.6%) in detecting TTI markers. CONCLUSION: The data do not provide any indication of a safety advantage from CUE; thus, we recommend that the procedure of CUE can be discontinued.

Acute promyelocytic leukemia derived extracellular vesicles conserve PML-RARα transcript from storage-inflicted degradation: a stable diagnosis tool in APL patients.

The early death, which is more common in acute promyelocytic leukemia (APL) patients rather than other types of acute myelocytic leukemia (AML) highlights the importance of appropriate diagnostic method for early detection of this disease. The low sensitivity of the conventional methods, low tumor burden in some patients, and the need for bone marrow sampling are some of the diagnostic challenges on the way of proper detection of APL. Given these, we aimed to compare the efficacy of extracellular vesicles (EVs), as a diagnostic tool, with the existing methods. RT-PCR, qPCR, and flow cytometry were applied on EVs and their corresponding associated cellular component collected from 18 APL new cases, 23 patients with minimal residual disease (MRD), and NB4 cell line. RT-PCR results were positive in both cellular and vesicular components of all new cases, NB4 cells, and EVs in contrary to MRD cases. Normalized copy numbers (NCN) of PML-RARα were 5100 and 3950 for cell and EVs, respectively (p < 0.05). There was a significant difference in the NCN of PML-RARα between cells and EVs in BM samples. Investigating the effect of storage at room temperature revealed that PML-RARα level was retained near to the baseline level in EVs, but there was a significant reduction in its copy number in the cellular component during 7 days. Taken together, given to the acceptable stability, EVs could be introduced as a non-invasive liquid biopsy that alongside existing methods could remarkably change the paradigm of APL diagnostic approaches.

The Relationship between Inflammatory Cytokines and Coagulopathy in Patients with COVID-19.

Coronavirus disease 2019 (COVID-19), with a broad range of clinical and laboratory findings, is currently the most prevalent medical challenge worldwide. In this disease, hypercoagulability and hyperinflammation, two common features, are accompanied by a higher rate of morbidity and mortality. We assessed the association between baseline inflammatory cytokine levels and coagulopathy and disease outcome in COVID-19. One hundred and thirty-seven consecutive patients hospitalized with COVID-19 were selected for the study. Baseline interleukin-1 (IL-1), IL-6, and tumor necrosis factor alpha (TNF-α) level were measured at time of admission. At the same time, baseline coagulation parameters were also assessed during the patient's hospitalization. Clinical findings, including development of thrombosis and clinical outcome, were recorded prospectively. Out of 136 patients, 87 (~64%) had increased cytokine levels (one or more cytokines) or abnormal coagulation parameters. Among them, 58 (~67%) had only increased inflammatory cytokines, 12 (~14%) had only coagulation abnormalities, and 17 (19.5%) had concomitant abnormalities in both systems. It seems that a high level of inflammatory cytokines at admission points to an increased risk of developing coagulopathy, thrombotic events, even death, over the course of COVID-19. Early measurement of these cytokines, and timely co-administration of anti-inflammatories with anticoagulants could decrease thrombotic events and related fatal consequences.

Serum Zinc Level in ß-Thalassemia Major: A Retrospective Study in Southwest Iran.

Thalassemia, which is associated with compound complications, is the most common hereditary anemia in the world. The zinc level is different in patients with thalassemias. This study aimed to determine the zinc status and its relationship with demographic factors and chelation therapy in ß-thalassemia major (ß-TM) patients. This cross-sectional study was conducted on 102 ß-thalassemia (ß-thal), patients. Zinc level was evaluated in subjects using the atomic absorption method. The results were analyzed through descriptive statistics, χ2 and Mann-Whitney U tests. Of 102 cases, 92 patients were eligible and evaluated. The mean age was 23 (minimum 11, maximum 43) years. Forty-six percent of cases were males and 54.0% were females. Of the 92 patients taking iron chelators, 29.3% used deferoxamine (DFO), 16.3% deferasirox (DFX), 20.6% DFO and deferiprone (DFP), and 33.8% DFO and DFP. All cases had zinc deficiency, 89.1% had zinc levels <40.0 mg/dL, and 10.9% with zinc levels >40.0 mg/dL. There was a significant relationship between gender and group with zinc levels greater than 40.0 mg/dL and those with less than 40.0 mg/dL. Zinc deficiency is highly prevalent among patients with thalassemia in the city of Yasuj, Iran. There was a significant relationship between zinc levels and gender although no significance was observed between zinc level and age, body mass index (BMI), ferritin, and chelation factors; it is recommended that these patients be periodically evaluated for zinc level. In case of a lack of laboratory evaluation, the use of prophylactic zinc supplementation should be considered for these patients.

Standardization of Prothrombin Time/International Normalized Ratio (PT/INR).

The prothrombin time (PT) represents the most commonly used coagulation test in clinical laboratories. The PT is mathematically converted to the international normalized ratio (INR) for use in monitoring anticoagulant therapy with vitamin K antagonists such as warfarin in order to provide test results that are adjusted for thromboplastin and instrument used. The INR is created using two major PT 'correction factors', namely the mean normal PT (MNPT) and the international sensitivity index (ISI). Manufacturers of reagents and coagulometers have made some efforts to harmonizing INRs, for example, by tailoring reagents to specific coagulometers and provide associated ISI values. Thus, two types of ISIs may be generated, with one being a 'general' or 'generic' ISI and others being reagent/coagulometer-specific ISI values. Although these play a crucial role in improving INR results between laboratories, these laboratories reported INR values are known to still differ, even when laboratories use the same thromboplastin reagent and coagulometer. Moreover, ISI values for a specific thromboplastin can vary among different models of coagulometers from a manufacturer using the same method for clot identification. All these factors can be sources of error for INR reporting, which in turn can significantly affect patient management. In this narrative review, we provide some guidance to appropriate ISI verification/validation, which may help decrease the variability in cross laboratory reporting of INRs.

COVID-19 and hematology findings based on the current evidences: A puzzle with many missing pieces.

In December 2019, a new type of coronavirus was detected for the first time in Wuhan, Hubei Province, China. According to the reported data, the emerging coronavirus has spread worldwide, infecting more than fifty-seven million individuals, leading to more than one million deaths. The current study aimed to review and discuss the hematological findings of COVID-19. Laboratory changes and hematologic abnormalities have been reported repeatedly in COVID-19 patients. WBC count and peripheral blood lymphocytes are normal or slightly reduced while these indicators may change with the progression of the disease. In addition, several studies demonstrated that decreased hemoglobin levels in COVID-19 patients were associated with the severity of the disease. Moreover, thrombocytopenia, which is reported in 5%-40% of patients, is known to be associated with poor prognosis of the disease. COVID-19 can present with various hematologic manifestations. In this regard, accurate evaluation of laboratory indicators at the beginning and during COVID-19 can help physicians to adjust appropriate treatment and provide special and prompt care for those in need.

Hb S (HBB: c.20A>T) and α- and ß-Thalassemia Coinheritance in Iranian Patients.

Hb S (HBB: c.20A>T) and α- and/or ß-thalassemia (α- and/or ß-thal) coinheritance is a common genetic disorder in regions with a high prevalence of thalassemia and sickle cell disease. The clinical manifestations of this coinheritance vary from mild to severe complications. Iran is a country with a high incidence of thalassemia and sickle cell disease. This study aimed to evaluate the coinheritance of sickle cell disease with α- and/or ß-thal in Iranian patients. In this cross-sectional study from 2018-2019, a total of 47 participants with the Hb S abnormality, who were referred to the Zafar Thalassemia Clinic (Tehran, Iran), were selected as a study group. Molecular analysis for the evaluation of α and ß gene mutations was performed in all participants. Hb SS, Hb S/ß-thal and Hb S/Hb D-Punjab (also known as Hb D-Los Angeles, Hb D-Chicago, Hb D-North Carolina, Hb D-Portugal and Hb Oak Ridge) (HBB: c.364G>C) were detected in 21 (44.7%), 23 (48.9%) and three (6.4%) patients, respectively. α Gene mutations were also detected in five patients with Hb S/ß-thal, four patients with sickle cell disease and one patient with Hb S/Hb D-Punjab. In the current study, -α3.7/αα with ß gene abnormalities was the most common genotype. Our study showed that the coinheritance of sickle cell disease with α- and ß-thal is common and evaluation of these disorders, especially in pre marriage screening is important for diagnosis and management strategies.

How hypoxia regulate exosomes in ischemic diseases and cancer microenvironment?

Exosomes, as natural occurring vesicles, play highly important roles in the behavior and fate of ischemic diseases and different tumors. Secretion, composition, and function of exosomes are remarkably influenced by hypoxia in ischemic diseases and tumor microenvironment. Exosomes secreted from hypoxic cells affect development, growth, angiogenesis, and progression in ischemic diseases and tumors through a variety of signaling pathways. In this review article, we discuss how hypoxia affects the quantity and quality of exosomes, and review the mechanisms by which hypoxic cell-derived exosomes regulate ischemic cell behaviors in both cancerous and noncancerous cells.

First-time Blood Donors Are Double-edged Swords for Blood Transfusion Centers: A Retrospective Study in Southwest Iran

Objective: First-time blood donors are the most common group of blood donors. They usually have different motivations for blood donation, some of which provoke the donors to hide risk factors of transfusion-transmissible infections (TTIs). Therefore, detection of TTIs among first-time donors is crucial and can decrease the rate of TTIs among blood recipients. This study aimed to evaluate the prevalence of TTIs among first-time donors in the transfusion center of Kohgiluyeh and Boyer-Ahmad Province (KBTC), Iran. Materials and Methods: This retrospective study was conducted with volunteer blood donors in 2004-2014 in the KBTC. Various data, including sex, confidential unit exclusion (CUE), previous donation history, and the laboratory findings of confirmatory tests, were extracted from blood donor software. Data were analyzed by SPSS using the chi-square test. Results: Among 198,501 blood donors, 52,527 (26.46%) were first-time donors, while 145,974 donors (73.54%) were repeat and regular donors. Most of the donors (94.5%) were male, while a minority (5.5%) were female. The CUE option was chosen by 2,237 (1.13%) donors. The incidence of hepatitis B surface antigen (HBsAg) and hepatitis C virus (HCV) was 247 (0.13%) and 134 (0.07%) among the entire study population, respectively. Three donors (0.002%) had confirmed human immunodeficiency virus (HIV), while none of the blood donors were positive for syphilis. Most of the donors with positive HBsAg (95.8%), HCV (86.6%), and HIV (100%) infection were first-time donors. Conclusion: Since TTIs are more common among first-time blood donors than regular and repeat donors, special considerations should be taken into account for this common group of blood donors.

Confidential unit exclusion (CUE): Double edged sword for blood transfusion center: A ten-year study on volunteer blood donors in Kohgiluyeh and Boyer Ahmad province, Iran.

BACKGROUND: Confidential unit exclusion (CUE) is a mechanism developed in the1980s to increase blood safety by allowing donors to indicate confidentially if they think their blood is not safe for transfusion. While it has been used widely around the world, the efficacy of this strategy is still unclear. The present study evaluated the efficacy of the CUE system at the Blood Transfusion Center of Kohgiluyeh and Boyer Ahmad Province (KBTC), Iran by comparing the prevalence of transfusion-transmitted infectious (TTIs) in CUE and non-CUE groups. METHODS: This descriptive study used data from all volunteer blood donors over a ten-year period. Donors were classified in two groups: CUE and non-CUE. Screening tests were performed for hepatitis B surface antigens (HBs-Ag), hepatitis C virus antibody (HCV-Ab), and Human immunodeficiency virus antibody (HIV-Ab) and any repeatedly reactive results were confirmed by standard methods. Significant differences were determined by Chi2 test. The sensitivity, specificity and PPV of the CUE system were also calculated. RESULTS: In the present study, the non-CUE and CUE groups consisted of 98.94% and 1.06% of volunteer blood donors, respectively. First-time donors selected the CUE option more often than repeated and regular donors. The prevalence of TTIs was significantly higher in the CUE group and CUE sensitivity, specificity, and PPV were 5.5%, 98.95%, and 0.96%, respectively. CONCLUSION: We recommend the CUE system be pursued for further enhancement of blood safety. However, further studies are needed to establish the overall usefulness of this procedure throughout the whole country.

The Effect of Demographic Factors and VKORC1 1639 G>A Genotypes on Estimated Warfarin Maintenance Dose in Iranian Patients Under Warfarin Therapy.

Warfarin is an anticoagulant that inhibits vitamin K-dependent clotting factors including factor (F) II, FVII, FIX and FX. Different factors can change the effect of this anticoagulant in clinic. Therefore we assessed impact of VKORC1 -1639 G>A polymorphism and demographic factors on required maintenance dose in Iranian patients under warfarin therapy. The study population included 95 patients with a mean age of 61.3 ± 12.6 years. Target INR range of 2-3 was considered for these patients. The frequency of VKORC1 -1639 G>A polymorphism was assessed by polymerase chain reaction-restriction length polymorphism (PCR-RFLP). Finally the obtain data were analyzed by SPSS software. Our study revealed that 30.5%, 49.5%, and 20% of the patients had VKORC1 (G/G), (G/A), and (A/A) genotypes, respectively. Carriers of VKORC1 G/G genotype required a higher warfarin dose as compared to A/A carriers (4.48 ± 1.32 and 2.7 ± 1.16 mg/day, respectively; P < 0.01). In addition, patients with higher age required lower warfarin therapeutic dose (r = - 0.3, P < 0.01). It seems that -1639 G>A polymorphism and demographic variables had significant effects on warfarin maintenance dose in Iranian patients under warfarin therapy.

Microvesicles of osteoblasts modulate bone marrow mesenchymal stem cell-induced apoptosis to curcumin in myeloid leukemia cells.

Microvesicles (MVs) derived from bone marrow niche components have an important role in genetic reprogramming and subsequent drugs induce apoptosis in leukemic cells. Here, we have found that undertreatment of curcumin or daunorubicin, the cross-talk through MVs of KG-1-bone marrow mesenchymal stem cells (BMSCs), significantly downregulates the expression of the survival gene osteopontin (OPN), CXCL-12, IL-6 (interleukin-6), STAT-3, and VCAM-1 (vascular cell adhesion molecule 1) in treated-KG-1 cells as well as exclusively upregulates CXCL-12 in BMSCs. Drug treated-cell populations' MVs of both single cultured osteoblasts (OBs) and cocultured KG-1 + BMSCs + OBs similarly upregulate survival mediators' OPN, CXCL-12, IL-6, STAT-3, and VCAM-1 in treated-KG-1 cells. Likewise, isolated MVs from KG-1 cells or communication between KG-1, BMSCs, and OBs treated by drugs increase the expression of genes OPN, CXCL-12, IL-6, STAT3, and VCAM-1 by OBs. MVs derived from KG-1 + BMSCs + OBs reduce drug-induced apoptosis in KG-1 cells. This suggests MVs-mediated information transfer is a procedure whereby OBs could overcome BMSCs-induced apoptosis in drug-treated-KG-1 cells.

Mesenchymal stem cell-based therapy for autoimmune diseases: emerging roles of extracellular vesicles.

In autoimmune disease body's own immune system knows healthy cells as undesired and foreign cells. Over 80 types of autoimmune diseases have been recognized. Currently, at clinical practice, treatment strategies for autoimmune disorders are based on relieving symptoms and preventing difficulties. In other words, there is no effective and useful therapy up to now. It has been well-known that mesenchymal stem cells (MSCs) possess immunomodulatory effects. This strongly suggests that MSCs might be as a novel modality for treatment of autoimmune diseases. Supporting this notion a few preclinical and clinical studies indicate that MSCs ameliorate autoimmune disorders. Interestingly, it has been found that the beneficial effects of MSCs in autoimmune disorders are not relying only on direct cell-to-cell communication but on their capability to produce a broad range of paracrine factors including growth factors, cytokines and extracellular vehicles (EVs). EVs are multi-signal messengers that play a serious role in intercellular signaling through carrying cargo such as mRNA, miRNA, and proteins. Numerous studies have shown that MSC-derived EVs are able to mimic the effects of the cell of origin on immune cells. In this review, we discuss the current studies dealing with MSC-based therapies in autoimmune diseases and provide a vision and highlight in order to introduce MSC-derived EVs as an alternative and emerging modality for autoimmune disorders.

The Prevalence and Trends of Hepatitis B, Hepatitis C, and HIV among Voluntary Blood Donors in Kohgiluyeh and Boyer-Ahmad Transfusion Center, Southwestern Iran.

BACKGROUND: Transfusion transmissible infections (TTIs) are a common complication of blood transfusion. Evaluation and monitoring the prevalence rate of TTIs in blood donors is a valuable indicator of donor selection and blood safety. We analyzed the trends of these infections among blood donors at Kohgiluyeh and Boyer-Ahmad transfusion service (KBTC) during 10 years. METHODS: Viral screening and confirmatory tests were carried out on 180304 voluntary donations from 2005-2014. The annual prevalence rates of hepatitis B virus (HBV), hepatitis C virus (HCV) and HIV infections per 100000 donations and 95% confidence interval were calculated. Chi-square test was applied to obtain the P-value. RESULTS: The overall prevalence was 0.13% for HBV and 0.06% for HCV while there were only three positive cases for HIV. The annual trend fluctuated during the time period studied. Compared to first-time donors, regular and repeat donors were significantly less likely to be positive for these infections. Outstandingly, this study provides first data in TTIs seropositivity rates among blood donors in our region; surprisingly were lower compared to other reports of Iran. CONCLUSION: The trends of TTIs prevalence in this study provide additional evidence that safety measures employed by the KBTC have been effective in maintaining a safe blood supply. The lower prevalence of TTIs in our study compared with other Iranian studies and also the general population reflects the efficacy of donor selection and education procedures in KBTC.

Reciprocal Interactions of Leukemic Cells with Bone Marrow Stromal Cells Promote Enrichment of Leukemic Stem Cell Compartments in Response to Curcumin and Daunorubicin

A predominant challenge in developing curative leukemia therapy is interactions of leukemic cells with the bone marrow stromal microenvironment. We aimed to investigate the role of stromal cells, such as bone marrow mesenchymal stromal cells (BMSCs) and osteoblasts (OBs), in curcumin (CUR) and daunorubicin (DNR) induced apoptosis of acute myeloid leukemia (AML) cells. We used KG1 and U937 as leukemia cell line models and treated them with CUR and DNR. The cells were then co-cultured with BMSCs or a combination of BMSCs and OBs as feeders. After 24 hours of co-culture, BMSCs or OBs were sorted and separated from the leukemia cells and apoptosis levels were analyzed by annexin/propidium iodide (PI) staining on flow cytometry. Potentially involved molecular pathways were analyzed at gene and protein levels by Real time PCR and western blotting, respectively. The results showed AML cells cocultured with BMSCs plus OBs to be more resistant to drug induced-apoptosis compared to co-culture with BMSCs alone or without co-culture. Expression levels of OPN, CXCL-12, IL-6, STAT-3 and VCAM-1 were also significantly up-regulated in OBs and AML cells, at both mRNA and protein levels after co-culture, with concurrent enrichment of CD34+ AML cells. Our data showed, in a stromal cell niche-based model, that OBs revoke the influence of BMSCs on leukemic cells and promote enrichment of both CD34+ and CD34- leukemic stem cell (LSC) compartments in response to CUR and DNR. Up-regulation of OPN, CXCL-12, IL-6, STAT-3 and VCAM-1 in OBs and AML cells in co-culture might be part of molecular mechanisms that block CUR or CUR+DNR-induced apoptosis and promote enrichment of CD34+ and CD34- LSCs.

Microvesicles preparation from mesenchymal stem cells.

BACKGROUND: Extracellular vesicles are particles ranged from 30 nm to 5µm and subcategorized into three groups; exosomes, microvesicles and apoptotic bodies, each of which have different biological impact. Lack of a standard method for the detection and isolation of MVs has led to a challenging issue that is a worth considering. In this study, we isolated MVs from the conditioned medium of UC-MSCs by four different schemes of ultracentrifugation. METHODS: We examined the efficacy of differential centrifugation ranging from 10,000×g to 60,000×g on UCMSCs- derived microvesicles yield and purity. The fractions were evaluated by Dynamic Light Scattering (DLS) method, total protein quantification and flow cytometry. RESULTS: UC-MSCs were spindle cells that adhered to plastic culture flasks. These cells expressed MSC markers such as CD44 and CD73, whereas were negative for hematopoietic markers CD45 and CD34. UC-MSCparticles were successfully isolated. Particles were heterogeneous vesicles of approximately 50 to 1250 nm in diameter that bear the surface-expressed molecules UC-MSCs such as; CD90, CD106, CD166 and CD44, and negative for CD34, CD63, and CD9. According to the results of DLS method, centrifugation at 10,000, 20,000, 40,000 and 60,000 ×g, all gave MVs of less than 1000 nm. It is of notion that only at the centrifugation rates of 40,000 and 60,000×g, particles of less than 100 nm in diameter were also obtained. CONCLUSION: The choice of exact speed greatly influences the purity of MVs and their yield. Our findings indicate that centrifugation at 20,000×g is appropriate for the purification of UC-MSC-MVs.