Personalized antiplatelet treatment after percutaneous coronary intervention: the MADONNA study.

BACKGROUND AND OBJECTIVES: Clopidogrel non-responsiveness is associated with adverse clinical outcome. We aimed to investigate whether individualized antiplatelet treatment in clopidogrel non-responders is an effective and safe strategy. METHODS: This was a prospective non-randomized non-blinded study comparing two cohorts (guided and non-guided treatment) with a follow-up of 1-month. Responsiveness to clopidogrel was assessed by multiple electrode aggregometry (MEA) in 798 patients with coronary artery disease undergoing percutaneous coronary intervention (PCI). In the guided group (n=403) clopidogrel non-responders received repeated loading doses of clopidogrel or prasugrel, in the non-guided group (n=395) clopidogrel non-responders did not undergo any change in treatment. RESULTS: Stent thrombosis occurred significantly less often in the guided group than in the non-guided group (0.2% vs. 1.9%; p=0.027). The multivariate Cox regression analysis showed that patients in the non-guided group were at a 7.9-fold higher risk to develop stent thrombosis compared to the guided group (OR: 7.9; 95% CI: 1.08-69.2; p=0.048). In line with this, acute coronary syndrome occurred significantly less often in the guided group than in the non-guided group (0% vs. 2.5%; p=0.001) whereas there was no difference in the event rates of cardiac death (2% vs. 1.3%; p=0.422) or major bleedings (1% vs. 0.3%; p=0.186). CONCLUSION: Personalized antiplatelet treatment according to the platelet function testing with MEA resulted in an improved efficacy with an equal safety compared to the standard treatment.

Rapid quantitation of cytomegalovirus DNA in whole blood by a new molecular assay based on automated sample preparation and real-time PCR.

Quantitation of cytomegalovirus (CMV) DNA in whole blood samples has gained significance in the routine diagnostic laboratory. In this study, the analytical performance of the artus™ CMV RG PCR kit in conjunction with automated sample preparation on the new QIAsymphony™ SP instrument was evaluated. Clinically referred samples were tested and results compared to those obtained with the routinely used molecular test system. Accuracy testing showed results to be within ±0.2 log(10) unit of the expected panel results. The assay was linear (R = 0.9972) from a lower quantification limit of 148 copies/ml to 1.3 × 10(7) copies/ml. The between-day imprecision CV was 8-63%, and the within-run imprecision CV was 16-61%. When 100 clinically referred samples were tested, results obtained with the new test system showed an acceptable concordance with those obtained with the routinely used easyMAG™ sample preparation and CMV HHV6,7,8 R-gene™ test system. Discrepant results were found with low-titer samples containing CMV DNA concentrations under the lower limit of quantification or within half a log unit above. The time to results was comparable for both test systems. The QIAsymphony™ sample preparation and artus™ CMV RG PCR test system allows for a rapid, sensitive, precise, and accurate high-throughput quantitation of CMV DNA in whole blood in the routine diagnostic laboratory.

Cell-free plasma DNA: a marker for apoptosis during hemodialysis.

BACKGROUND: We evaluated whether cell-free plasma DNA might be an appropriate marker for cell damage during hemodialysis (HD) and whether it correlated with annexin V expression and 7-amino-actinomycin D (7AAD) nuclear staining of blood leukocytes. METHODS: Circulating DNA, annexin V, and 7AAD were measured in HD patients before HD, 20 min after start of HD, and after HD had ended. Healthy volunteers provided control measurements. Necrosis and apoptosis were monitored by gel electrophoresis. RESULTS: Plasma DNA concentrations were not significantly different between controls and patients before HD. Circulating DNA increased significantly (P < 0.05) after 20 min of treatment with HD. Post-HD concentrations of DNA were significantly higher compared with pre-HD and controls (P < 0.005). Agarose gel electrophoresis showed ladders typical of apoptosis in post-HD samples. Two subpopulations of CD45+ leukocytes were defined by flow cytometry: annexin V+/7AAD+ population for apoptosis, and annexin V+/7AAD- for early apoptosis. Compared with healthy controls, mean fluorescence (MF) of 7AAD+ apoptotic cells in the annexin V+/7AAD+ subpopulation before HD was not significantly increased. HD increased MF of 7AAD+ cells in the annexin V+/7AAD+ subpopulation. In this subpopulation, MF of annexin V+ cells was significantly higher (P < 0.01). MF of annexin V+ cells in the annexin V+/7AAD+ subpopulation increased during HD. CONCLUSIONS: During HD, cell-free plasma DNA concentrations, annexin V expression, and 7AAD uptake in leukocytes increases. The increase in plasma DNA, appearing as ladders typical of apoptosis, and the 7AAD uptake in leukocytes demonstrate that the predominant portion of circulating DNA in HD patients originates from apoptotic leukocytes.

Differentiation of human umbilical cord blood CD133+ stem cells towards myelo-monocytic lineage.

BACKGROUND: Characterisation of stem cells by flow cytometry, their expansion and differentiation are presently of major interest for cell engineering as the basis of a therapeutic concept for transplantation. Haematopoietic stem cells (HSC) express CD34, the adhesion structure which binds 2L-selectin, CD117, a receptor for stem cell factor (SCF; c-kit ligand), and CD133, a transmembrane protein belonging to the family of mucoproteins. METHODS: The aim of the present investigation was the systematic investigation of proliferation and differentiation characteristics of umbilical cord blood stem cells (UCBSC) isolated by an immmunomagnetic separation system using CD133 antibody-coated microbeads and to evaluate the effects of different sera and various concentrations, as well as the effects of IL-3 and IL-6 on total cell expansion and differentiation of isolated CD133+ cells. Differentiation patterns were measured by flow cytometry. RESULTS: After the immmunomagnetic separation the yield of CD133+ cells was 0.45+/-0.17 x 10(6) cells/ml; the purity of isolated CD133+ cells was 95.79+/-1.86%. The majority of CD133+ cells coexpressed CD117. The most pronounced expansion during cultivation of 2 weeks was achieved in media supplemented with 12.5% horse serum plus 12.5% fetal calf serum (FCS) with stem cell factor and interleukine 3; the fold-expansion was 16.67+/-6.20. During the cultivation period, UCBSC were constantly loosing stem cell markers and differentiated towards myelo-monocyte lineage (granulocytes and/or monocytes). CONCLUSIONS: These in vitro results demonstrate that thorough investigation of various cultivation conditions is needed for successful expansion and differentiation of stem cells towards different lineages to be used therapeutically for replacement of damaged cells.

Cell cycle analysis of the CD133+ and CD133- cells isolated from umbilical cord blood.

BACKGROUND: Umbilical cord blood cells (stem/progenitor cells) exhibit high proliferative capacities leading to a large expansion of cells in appropriate cell culture conditions. The aim of this study was to evaluate by flow cytometry the cycling status of CD133+ and CD133- cells depending on various culture conditions, such as sera, stem cell factor (SCF), interleukin 3 (IL-3) and interleukin 6 (IL-6). METHODS: An immunomagnetic system was used for cell separation. CD133+ and CD133- cells were seeded in Iscove's Modified Dulbecco's Medium (IMDM) with different serum concentrations and were stimulated with SCF (100 ng/ml), IL-3 (50 ng/ml) and IL-6 (50 ng/ml). RESULTS: Our experiments demonstrated that immediately after separation, 96.75+/-0.58% of CD133+ cells and 97.04+/-1.76% of CD133- cells were in G0/G1-phase, while 2.02+/-0.38% and 0.88+/-0.52% were in the S-phase, respectively. Our data documented that CD133+ cells are more active than CD133- cells after the first week of cultivation (p<0.01). Statistically significant difference was found for CD133+ cells vs. CD133- cells after second week of cultivation in G0/G1- and S-phases under all tested conditions. A combination of 12.5% FCS+12.5% HS yielded the highest cell expansion for CD133+ cells; this was concomitant with highest percentage of S-phase and G2M-phase. Our data show that the medium with 25% HS was the best for cell expansion and cycling of the CD133- cells for the first week, followed by the 12.5% FCS+12.5% HS. After 2 weeks of cultivation, obviously 12.5% HS and 12.5% FCS+12.5% HS exhibited similar S-phase amounts in CD133- cells. A decrease of HS concentrations seemed to stimulate CD133- cells' S-phase after the second week. CONCLUSIONS: Our data indicate that the source and the concentration of the serum used for cultivation have an impact on both cell populations: CD133+ cells are most comfortable with a combination of FCS and HS; CD133- cells prefer media-containing HS. Cell cycle status may be an important factor for defining cultivation strategies for stem cell expansion.

Leptin induces endothelin-1 in endothelial cells in vitro.

Leptin, a protein encoded by the obese gene, is produced by adipocytes and released into the bloodstream. In obese humans, serum leptin levels are increased and correlate with the individual's body mass index and blood pressure. Elevated serum concentrations of endothelin-1 (ET-1), a potent vasoconstrictor and mitogen, were also observed in obese subjects. The pathomechanisms underlying this ET-1 increase in obesity are poorly understood. In the present study, we investigated the influence of the ob gene product leptin on the expression of ET-1 in human umbilical vein endothelial cells (HUVECs). Binding studies using (125)I-radiolabeled leptin revealed high- and low-affinity leptin binding sites on HUVECs (Kd1=13.1+/-3.1 nmol/L and Kd2=1390+/-198 nmol/L, respectively), mediating a time- and dose-dependent increase of ET-1 mRNA expression and protein secretion after incubation of HUVECs with leptin. This leptin-induced ET-1 expression was inhibited by preincubation of HUVECs with 0.75 micromol/L antisense phosphorothioate oligonucleotides directed against the leptin receptor Ob-Rb. Furthermore, after incubation with leptin, increased nuclear staining of c-fos and c-jun, the major components of the transcription factor AP-1, and increased AP-1 DNA binding were observed. Transient transfection studies with ET-1 promoter constructs showed that leptin-induced promoter activity was abolished in the absence of AP-1 binding sites or by cotransfection with a plasmid overexpressing a mutated jun, which is able to bind c-fos but not DNA. Thus, leptin upregulates ET-1 production in HUVECs via a mechanism potentially involving jun binding members of the bZIP family.