Circulating Very Small Embryonic-Like Stem Cells in Cardiovascular Disease

Very small embryonic-like cells (VSELs) are a population of stem cells residing in the bone marrow (BM) and several organs, which undergo mobilization into peripheral blood (PB) following acute myocardial infarction and stroke. These cells express markers of pluripotent stem cells (PSCs), such as Oct-4, Nanog, and SSEA-1, as well as early cardiac, endothelial, and neural tissue developmental markers. VSELs can be effectively isolated from the BM, umbilical cord blood, and PB. Peripheral blood and BM-derived VSELs can be expanded in co-culture with C2C12 myoblast feeder layer and undergo differentiation into cells from all three germ layers, including cardiomyocytes and vascular endothelial cells. Isolation of VSLEs using fluorescence-activated cell sorting multiparameter live cell sorting system is dependent on gating strategy based on their small size and expression of PSC and absence of hematopoietic lineage markers. VSELs express early cardiac and endothelial lineages markers (GATA-4, Nkx2.5/Csx, VE-cadherin, and von Willebrand factor), SDF-1 chemokine receptor CXCR4, and undergo rapid mobilization in acute MI and ischemic stroke. Experiments in mice showed differentiation of BM-derived VSELs into cardiac myocytes and effectiveness of expanded and pre-differentiated VSLEs in improvement of left ventricular ejection fraction after myocardial infarction

Transcriptional landscape of bone marrow-derived very small embryonic-like stem cells during hypoxia

<p>Abstract</p> <p>Background</p> <p>Hypoxia is a ubiquitous feature of many lung diseases and elicits cell-specific responses. While the effects of hypoxia on stem cells have been examined under <it>in vitro </it>conditions, the consequences of <it>in vivo </it>oxygen deprivation have not been studied.</p> <p>Methods</p> <p>We investigated the effects of <it>in vivo </it>hypoxia on a recently characterized population of pluripotent stem cells known as very small embryonic-like stem cells (VSELs) by whole-genome expression profiling and measuring peripheral blood stem cell chemokine levels.</p> <p>Results</p> <p>We found that exposure to hypoxia in mice mobilized VSELs from the bone marrow to peripheral blood, and induced a distinct genome-wide transcriptional signature. Applying a computationally-intensive methodology, we identified a hypoxia-induced gene interaction network that was functionally enriched in a diverse array of programs including organ-specific development, stress response, and wound repair. Topographic analysis of the network highlighted a number of densely connected hubs that may represent key controllers of stem cell response during hypoxia and, therefore, serve as putative targets for altering the pathophysiologic consequences of hypoxic burden.</p> <p>Conclusions</p> <p>A brief exposure to hypoxia recruits pluripotent stem cells to the peripheral circulation and actives diverse transcriptional programs that are orchestrated by a selective number of key genes.</p

Sphingosine-1-Phosphate-Mediated Mobilization of Hematopoietic Stem/Progenitor Cells During Intravascular Hemolysis Requires Attenuation of SDF-1-CXCR4 Retention Signaling in Bone Marrow

Sphingosine-1-phosphate (S1P) is a crucial chemotactic factor in peripheral blood (PB) involved in the mobilization process and egress of hematopoietic stem/progenitor cells (HSPCs) from bone marrow (BM). Since S1P is present at high levels in erythrocytes, one might assume that, by increasing the plasma S1P level, the hemolysis of red blood cells would induce mobilization of HSPCs. To test this assumption, we induced hemolysis in mice by employing phenylhydrazine (PHZ). We observed that doubling the S1P level in PB from damaged erythrocytes induced only a marginally increased level of mobilization. However, if mice were exposed to PHZ together with the CXCR4 blocking agent, AMD3100, a robust synergistic increase in the number of mobilized HSPCs occurred. We conclude that hemolysis, even if it significantly elevates the S1P level in PB, also requires attenuation of the CXCR4-SDF-1 axis-mediated retention in BM niches for HSPC mobilization to occur. Our data also further confirm that S1P is a major chemottractant present in plasma and chemoattracts HSPCs into PB under steady-state conditions. However, to egress from BM, HSPCs first have to be released from BM niches by blocking the SDF-1-CXCR4 retention signal

Spinal Cord Injury Repair by Intrathecal Infusion of Stromal Cell-Derived Factor-1/CXC Chemokine Receptor 4 in a Rat Model

Background: Stromal cell-derived factor-1 (SDF-1)/CXC Chemokine receptor 4 (CXCR4) is an important cytokine, with multiple functions, which plays a crucial role in the recruitment of multiple stem cell types in the defect sites of central nervous system (CNS). Various strategies have been managed to improve functional recovery after spinal cord injury (SCI). One of these strategies is the use of factors to limit damage and increase recovery. Objectives: In this study we investigated the effect of SDF-1 in spinal cord injury repair in a rat model. Materials andMethods: Adult male Wistar rats were randomly divided to four groups (n = 5) as follows: Sham, SCI, SDF-1 and Vehicle. Spinal cord injury model was created by contusion of T8-T9 by clips and SDF-1 infusion pump implanted in the neck region. One week after injury, 5-Bromo-20-Deoxyuridine (BrdU) was injected to trace the proliferative cells. Basso-Beattie-Bresnahan (BBB) test was performed to evaluate locomotor activity following SCI. Immunohistochemistry test was performed to determine proliferating cells, and real time polymerase chain reaction (PCR) was performed to detect the CXCR4 cells in tissue. Results: Significant improvements in locomotor function were detected in the SDF-1 group compared with the SCI and vehicle groups (P < 0.05). The results showed that SDF-1 treatment increased proliferative cells at the spinal cord injury site. Real time PCR revealed that these proliferative cells are CXCR4 positive that intake Bromodeoxyuridine (Brdu). Conclusions: These results showed that the administration of SDF-1a increases the number of proliferating cells in the injured area in the spinal cord and improves functional recovery

Rhabdomyosarcoma cells show an energy producing anabolic metabolic phenotype compared with primary myocytes

<p>Abstract</p> <p>Background</p> <p>The functional status of a cell is expressed in its metabolic activity. We have applied stable isotope tracing methods to determine the differences in metabolic pathways in proliferating Rhabdomysarcoma cells (Rh30) and human primary myocytes in culture. Uniformly ¹³C-labeled glucose was used as a source molecule to follow the incorporation of ¹³C into more than 40 marker metabolites using NMR and GC-MS. These include metabolites that report on the activity of glycolysis, Krebs' cycle, pentose phosphate pathway and pyrimidine biosynthesis.</p> <p>Results</p> <p>The Rh30 cells proliferated faster than the myocytes. Major differences in flux through glycolysis were evident from incorporation of label into secreted lactate, which accounts for a substantial fraction of the glucose carbon utilized by the cells. Krebs' cycle activity as determined by ¹³C isotopomer distributions in glutamate, aspartate, malate and pyrimidine rings was considerably higher in the cancer cells than in the primary myocytes. Large differences were also evident in de novo biosynthesis of riboses in the free nucleotide pools, as well as entry of glucose carbon into the pyrimidine rings in the free nucleotide pool. Specific labeling patterns in these metabolites show the increased importance of anaplerotic reactions in the cancer cells to maintain the high demand for anabolic and energy metabolism compared with the slower growing primary myocytes. Serum-stimulated Rh30 cells showed higher degrees of labeling than serum starved cells, but they retained their characteristic anabolic metabolism profile. The myocytes showed evidence of de novo synthesis of glycogen, which was absent in the Rh30 cells.</p> <p>Conclusion</p> <p>The specific ¹³C isotopomer patterns showed that the major difference between the transformed and the primary cells is the shift from energy and maintenance metabolism in the myocytes toward increased energy and anabolic metabolism for proliferation in the Rh30 cells. The data further show that the mitochondria remain functional in Krebs' cycle activity and respiratory electron transfer that enables continued accelerated glycolysis. This may be a common adaptive strategy in cancer cells.</p

Validation of a Thin-Layer Chromatography for the Determination of Hydrocortisone Acetate and Lidocaine in a Pharmaceutical Preparation

A new specific, precise, accurate, and robust TLC-densitometry has been developed for the simultaneous determination of hydrocortisone acetate and lidocaine hydrochloride in combined pharmaceutical formulation. The chromatographic analysis was carried out using a mobile phase consisting of chloroform + acetone + ammonia (25%) in volume composition 8 : 2 : 0.1 and silica gel 60F 254 plates. Densitometric detection was performed in UV at wavelengths 200 nm and 250 nm, respectively, for lidocaine hydrochloride and hydrocortisone acetate. The validation of the proposed method was performed in terms of specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, and robustness. The applied TLC procedure is linear in hydrocortisone acetate concentration range of 3.75 ÷ 12.50 g⋅spot −1 , and from 1.00 ÷ 2.50 g⋅spot −1 for lidocaine hydrochloride. The developed method was found to be accurate (the value of the coefficient of variation CV [%] is less than 3%), precise (CV [%] is less than 2%), specific, and robust. LOQ of hydrocortisone acetate is 0.198 g⋅spot −1 and LOD is 0.066 g⋅spot −1 . LOQ and LOD values for lidocaine hydrochloride are 0.270 and 0.090 g⋅spot −1 , respectively. The assay value of both bioactive substances is consistent with the limits recommended by Pharmacopoeia

Very small embryonic-like stem cells (VSELs) represent a real challenge in stem cell biology : recent pros and cons in the midst of a lively debate

The concept that adult tissue, including bone marrow (BM), contains early-development cells with broader differentiation potential has again been recently challenged. In response, we would like to review the accumulated evidence from several independent laboratories that adult tissues, including BM, harbor a population of very rare stem cells that may cross germ layers in their differentiation potential. Thus, the BM stem cell compartment hierarchy needs to be revisited. These dormant, early-development cells that our group described as very small embryonic-like stem cells (VSELs) most likely overlap with similar populations of stem cells that have been identified in adult tissues by other investigators as the result of various experimental strategies and have been given various names. As reported, murine VSELs have some pluripotent stem cell characteristics. Moreover, they display several epiblast/germline markers that suggest their embryonic origin and developmental deposition in adult BM. Moreover, at the molecular level, changes in expression of parentally imprinted genes (for example, Igf2–H19) and resistance to insulin/insulin-like growth factor signaling (IIS) regulates their quiescent state in adult tissues. In several emergency situations related to organ damage, VSELs can be activated and mobilized into peripheral blood, and in appropriate animal models they contribute to tissue organ/regeneration. Interestingly, their number correlates with lifespan in mice, and they may also be involved in some malignancies. VSELs have been successfully isolated in several laboratories; however, some investigators experience problems with their isolation