Red Blood Cell Contamination of the Final Cell Product Impairs the Efficacy of Autologous Bone Marrow Mononuclear Cell Therapy

ObjectivesThe aim of this study was to identify an association between the quality and functional activity of bone marrow-derived progenitor cells (BMCs) used for cardiovascular regenerative therapies and contractile recovery in patients with acute myocardial infarction included in the placebo-controlled REPAIR-AMI (Reinfusion of Enriched Progenitor cells And Infarct Remodeling in Acute Myocardial Infarction) trial.BackgroundIsolation procedures of autologous BMCs might affect cell functionality and therapeutic efficacy.MethodsQuality of cell isolation was assessed by measuring the total number of isolated BMCs, CD34+ and CD133+ cells, their colony-forming unit (CFU) and invasion capacity, cell viability, and contamination of the final BMC preparation with thrombocytes and red blood cells (RBCs).ResultsThe number of RBCs contaminating the final cell product significantly correlated with reduced recovery of left ventricular ejection fraction 4 months after BMC therapy (p = 0.007). Higher numbers of RBCs in the BMC preparation were associated with reduced BMC viability (r = −0.23, p = 0.001), CFU capacity (r = −0.16, p = 0.03), and invasion capacity (r = −0.27, p < 0.001). To assess a causal role for RBC contamination, we coincubated isolated BMCs with RBCs for 24 h in vitro. The addition of RBCs dose-dependently abrogated migratory capacity (p = 0.003) and reduced CFU capacity (p < 0.05) of isolated BMCs. Neovascularization capacity was significantly impaired after infusion of BMCs contaminated with RBCs, compared with BMCs alone (p < 0.05). Mechanistically, the addition of RBCs was associated with a profound reduction in mitochondrial membrane potential of BMCs.ConclusionsContaminating RBCs affects the functionality of isolated BMCs and determines the extent of left ventricular ejection fraction recovery after intracoronary BMC infusion in patients with acute myocardial infarction. These results suggest a bioactivity response relationship very much like a dose–response relationship in drug trials. (Reinfusion of Enriched Progenitor cells and Infarct Remodeling in Acute Myocardial Infarction [REPAIR-AMI]; NCT00279175

Streptococcus pneumoniae Serotype 1 Capsular Polysaccharide Induces CD8+CD28− Regulatory T Lymphocytes by TCR Crosslinking

Zwitterionic capsular polysaccharides (ZPS) of commensal bacteria are characterized by having both positive and negative charged substituents on each repeating unit of a highly repetitive structure that has an α-helix configuration. In this paper we look at the immune response of CD8+ T cells to ZPSs. Intraperitoneal application of the ZPS Sp1 from Streptococcus pneumoniae serotype 1 induces CD8+CD28− T cells in the spleen and peritoneal cavity of WT mice. However, chemically modified Sp1 (mSp1) without the positive charge and resembling common negatively charged polysaccharides fails to induce CD8+CD28− T lymphocytes. The Sp1-induced CD8+CD28− T lymphocytes are CD122lowCTLA-4+CD39+. They synthesize IL-10 and TGF-β. The Sp1-induced CD8+CD28− T cells exhibit immunosuppressive properties on CD4+ T cells in vivo and in vitro. Experimental approaches to elucidate the mechanism of CD8+ T cell activation by Sp1 demonstrate in a dimeric MHC class I-Ig model that Sp1 induces CD8+ T cell activation by enhancing crosslinking of TCR. The expansion of CD8+CD28− T cells is independent, of direct antigen-presenting cell/T cell contact and, to the specificity of the T cell receptor (TCR). In CD8+CD28− T cells, Sp1 enhances Zap-70 phosphorylation and increasingly involves NF-κB which ultimately results in protection versus apoptosis and cell death and promotes survival and accumulation of the CD8+CD28− population. This is the first description of a naturally occurring bacterial antigen that is able to induce suppressive CD8+CD28− T lymphocytes in vivo and in vitro. The underlying mechanism of CD8+ T cell activation appears to rely on enhanced TCR crosslinking. The data provides evidence that ZPS of commensal bacteria play an important role in peripheral tolerance mechanisms and the maintenance of the homeostasis of the immune system

Associations between depressive symptoms and disease progression in older patients with chronic kidney disease: results of the EQUAL study

Background Depressive symptoms are associated with adverse clinical outcomes in patients with end-stage kidney disease; however, few small studies have examined this association in patients with earlier phases of chronic kidney disease (CKD). We studied associations between baseline depressive symptoms and clinical outcomes in older patients with advanced CKD and examined whether these associations differed depending on sex. Methods CKD patients (&gt;= 65 years; estimated glomerular filtration rate &lt;= 20 mL/min/1.73 m(2)) were included from a European multicentre prospective cohort between 2012 and 2019. Depressive symptoms were measured by the five-item Mental Health Inventory (cut-off &lt;= 70; 0-100 scale). Cox proportional hazard analysis was used to study associations between depressive symptoms and time to dialysis initiation, all-cause mortality and these outcomes combined. A joint model was used to study the association between depressive symptoms and kidney function over time. Analyses were adjusted for potential baseline confounders. Results Overall kidney function decline in 1326 patients was -0.12 mL/min/1.73 m(2)/month. A total of 515 patients showed depressive symptoms. No significant association was found between depressive symptoms and kidney function over time (P = 0.08). Unlike women, men with depressive symptoms had an increased mortality rate compared with those without symptoms [adjusted hazard ratio 1.41 (95% confidence interval 1.03-1.93)]. Depressive symptoms were not significantly associated with a higher hazard of dialysis initiation, or with the combined outcome (i.e. dialysis initiation and all-cause mortality). Conclusions There was no significant association between depressive symptoms at baseline and decline in kidney function over time in older patients with advanced CKD. Depressive symptoms at baseline were associated with a higher mortality rate in men

Synthesis and characterisation of moel-composites based on multiwalled carbon nanotubes and SiO2

Der große Elastizitätsmodul und die große Biegedehnung von CNTs führt zu großem Interesse an ihrer Verwendung als Verstärkungsfasern in nanostrukturierten Verbunden. Dieses Interesse gab den Anlaß zu dieser Arbeit. Es wurden Methoden zur Modifizierung der chemisch wenig reaktiven Oberfläche von MWNTs entwickelt. Brom stellte sich dabei als besonders effektiv heraus: TGA sowie HRTEM lassen auf eine Veränderung der CNT-Mantelflächen schließen. Durch Anwendung von Polyelektrolyten wie Polyethylemin (PEI) und Polyacrylsäure (PAA) konnte die Dispergierbarkeit von MWNTs in Wasser wesentlich verbessert werden. Zetapotentialmessungen zeigten, daß die polymerbehandelten CNTs eine erhöhtes Oberflächenpotential aufweisen. Die mit PEI vorbehandelten CNTs ließen sich bei Raumtemperatur mit SiOx-Gel beschichten. Ein anderes Verfahren zur SiOx-Beschichtung basiert auf der Adsorption von Tetraethylorthosilicat (TEOS) auf der CNT-Oberfläche und dessen nachfolgender Zersetzung bei erhöhter Temperatur. Die geringe Benetzbarkeit von MWNTs wurde durch Anwendung der Sol-Gel Technik zur Herstellung eines CNT/SiO2-Volumenverbundes überwunden. In Preß- und Sinterschritten bei 1150 °C entstanden dann Volumenverbunde. Hier ist ein Teil der MWNTs von der SiO2-Matrix umschlossen. Eine Bindung von MWNTs an die Matrix im Verbund konnte gefunden werden. Auf dieser Grundlage und anhand theoretischer Rechnungen wird eine Bindung über Si-C Brücken vorgeschlagen. Durch Einbettung in der SiO2-Matrix bleiben 16 des Kohlenstoffes bis zu 1220 °C an Luft stabil. Diese Temperatur liegt deutlich oberhalb der Oxidationstemperatur reinen MWNT-Materials (ca. 800 °C). Nach der TGA bis 1220 °C konnten MWNTs im Volumenverbund nachgewiesen werden. Es gelang, durch Verdampfung von Fe/Si-gefüllten Graphitelektroden im Lichbogen, SiC Nanowhisker herzustellen. Für das Wachstum wurde der VLS-Mechanismus (vapour-liquid-solid: VLS) für den Lichbogen weiterentwickelt.The high stiffness and flexibility of carbon nanotubes (CNT) lead to growing interest in the use of CNT as reinforcing fibers in nanostructured composites. Therefore, the synthesis of CNT-model-composites is the main issue of this thesis. Methods for the modification of the chemically inert CNT-surface have been developed. Bromine in combination with ultrasonic treatment has been found to be efficient: TGA and HRTEM show consistantly the modification of the CNT-sidewalls. The stability of aqueous CNT suspensions was substantially improved by polyethyemine (PEI) and polyacrylic acid (PAA). Zetapotential measurements showed that these CNT exhibit an enhanced negative or positive surface-potential. A room-temperature coating technique of CNT has been developed involving a silica-sol and PEI-pretreated CNT. An other technique involves adsorption of TEOS on the CNT-surface and subsequent decomposition at 1000 °C. No chemical bonding has been observed between the coating and the CNT for either technique. The poor wetting of CNT has been surmounted using a sol-gel technique for the production of a CNT/SiO2-bulk-composite. The final composite has been achieved by uniaxial pressing and sintering at 1150 °C. TEM characterisation showed that some of the CNT were incorporated within the matrix. A CNT-matrix bonding was shown for the first time in an inorganic matrix. Together with theoretical calculations a Si-C bonding between the CNT and the SiO2-matrix is proposed. Due to the incorporation of CNT in the SiO2-matrix 16 of the carbon remains stable up to 1220 °C in air. This temperature is much higher than the oxidation temperature of pure arc-discharge CNT (ca. 800 °C). CNT can be found easily in the composite after the TGA. The production of SiC-nanowhiskers has been achieved by evaporation of Fe/Si-filled graphite-electrodes. A mechanism for the whisker growth in the arc-discharge has been developed on the basis of the VLS (vapour-liquid-solid)-mechanism