Ralf Schubert

Goethe-Universität Frankfurt am Main, Frankfurt am Main, Hesse, Germany

Are you Ralf Schubert?

Claim your profile

Publications (48)162.32 Total impact

  • Article: Bronchial allergen provocation: A useful method to assess the efficacy of specific immunotherapy in children.
    [show abstract] [hide abstract]
    ABSTRACT: BACKGROUND: The clinical efficacy of subcutaneous allergen-specific immunotherapy (SCIT) varies between patients. New preparations are under development, and an objective tool with which to evaluate their efficacies in individual patients has become necessary. Our primary research question is whether bronchial allergen provocation (BAP) can be used to assess the efficacy of SCIT. METHODS: In 42 house dust mite (HDM) allergic children (average age: 8.6 yr) with asthma, we analysed the clinical and objective improvements of a standardised HDM allergoid. All patients underwent two BAPs, one before SCIT and another 1 yr after SCIT. Fourteen patients who were recommended but chose not to undergo SCIT represented the control group. The total and specific IgE were analysed before SCIT; in addition, after SCIT, specific IgG and IgG4 were analysed. RESULTS: After SCIT, the patients' allergen-specific bronchial hyper-reactivity (BHR) was significantly improved; specifically, their PD20 FEV1 was 34.4 AU before and 63.3 AU after SCIT (p < 0.01). The PD20 FEV1 of the control group remained unchanged. Although BHR improved significantly in the treatment group, we were able to differentiate between the responders (n = 17, 60.7%) and non-responders (n = 11, no improvement in BAP). The patients in both groups stated that SCIT had led to a subjective improvement in their symptoms, in contrast to the untreated control group, but only the responders required less medication after SCIT (p < 0.01). CONCLUSIONS: After 1 yr of SCIT against HDM, 60.7% of the patients observed in this study exhibited significant improvements, as defined by BAP. However, BAP was also able to identify the non-responders to treatment. Thus, BAP is a useful and objective method of estimating the effectiveness of SCIT and is not influenced by a placebo effect.
    Pediatric Allergy and Immunology 04/2013; · 2.46 Impact Factor
  • Article: Non-surgical periodontal therapy decreases serum elastase levels in aggressive but not in chronic periodontitis.
    [show abstract] [hide abstract]
    ABSTRACT: AIM: Assessment of the effect of non-surgical periodontal therapy (SRP) on serum inflammatory parameters in patients with untreated aggressive (AgP) and chronic (ChP) periodontitis. METHODS: Overall, 31 ChP and 29 AgP were examined clinically prior to and 12 weeks after SRP (subgingival scaling of all pockets within 2 days) with systemic antibiotics for patients positive for Aggregatibacter actinomycetemcomitans (14 AgP, 9 ChP). Blood was sampled prior to, one day, 6, and 12 weeks after the first SRP visit. Serum elastase, C-reactive protein (CRP), lipopolysaccharide-binding protein (LBP), interleukin (IL) 6, 8, and leukocyte counts were assessed. RESULTS: At baseline, serum elastase, CRP, and LBP were significantly (p < 0.01) higher in AgP than ChP. Serum elastase, CRP, LBP, and IL-6 were significantly (p < 0.001) elevated one day after scaling in both groups. Both groups showed significant clinical improvement (p < 0.001). A significant difference was observed regarding change of serum elastase 12 weeks after SRP between AgP and ChP (p = 0.015). Multiple regression analysis revealed AgP, African origin, and bleeding on probing to be associated with more pronounced elastase reduction. CRP reduction was associated with African origin, systemic antibiotics, and baseline probing pocket depth. CONCLUSION: SRP results in serum elastase reduction in AgP but not in ChP.
    Journal Of Clinical Periodontology 01/2013; · 3.00 Impact Factor
  • Article: Airway responses and inflammation in subjects with asthma after four days of repeated high-single-dose allergen challenge.
    [show abstract] [hide abstract]
    ABSTRACT: Both standard and low-dose allergen provocations are an established tool in asthma research to improve our understanding of the pathophysiological mechanism of allergic asthma. However, clinical symptoms are less likely to be induced. Therefore, we designed a protocol for repetitive high-dose bronchial allergen challenges to generate clinical symptoms and airway inflammation. A total of 27 patients aged 18 to 40 years with positive skin-prick tests and mild asthma underwent repetitive high-dose allergen challenges with household dust mites for four consecutive days. Pulmonary function and exhaled NO were measured at every visit. Induced sputum was analysed before and after the allergen challenges for cell counts, ECP, IL-5, INF-γ, IL-8, and the transcription factor Foxp3. We found a significant decrease in pulmonary function, an increased use of salbutamol and the development of a late asthmatic response and bronchial hyperresponsiveness, as well as a significant induction of eNO, eosinophils, and Th-2 cytokines. Repeated provocation was feasible in the majority of patients. Two subjects had severe adverse events requiring prednisolone to cope with nocturnal asthma symptoms. Repeated high-dose bronchial allergen challenges resulted in severe asthma symptoms and marked Th-2-mediated allergic airway inflammation. The high-dose challenge model is suitable only in an attenuated form in diseased volunteers for proof-of-concept studies and in clinical settings to reduce the risk of severe asthma exacerbations. ClinicalTrials.govNCT00677209.
    Respiratory research 09/2012; 13:78. · 3.36 Impact Factor
  • Article: Comprehensive Phenotypic Characterization of Human Adipose-Derived Stromal/Stem Cells and Their Subsets by a High Throughput Technology.
    [show abstract] [hide abstract]
    ABSTRACT: The characterization of adipose-derived stromal/stem cells (ASCs) remains difficult due to the lack of a definitive and unique cellular marker. Therefore, a combination of markers is necessary to identify the cells. No comprehensive analysis of the immunophenotype of expanded plastic adherent ASCs has been published. Therefore, the aim of this study was to characterize the general phenotype of cultured ASCs and to further analyze cellular subsets. ASCs were isolated from lipoaspirates from patients undergoing cosmetic liposuction and cultured in standard cell culture. A comprehensive phenotype characterization was done with the BD Lyoplate™ Human Cell Surface Marker Screening Panel containing 242 antibodies and isotype controls. Cultured ASCs not only showed the characteristic expression profile of mesenchymal stem cells (MSCs), but also revealed donor-specific variability in the expression of 49 other markers. We further detected markers with a scattering in the fluorescence intensity, indicating subpopulations with different expression profiles. Therefore, a multi-color flow cytometric analysis was done after staining the cells with direct-labeled antibodies against CD73, CD90, CD105, and either CD34, CD140b, CD200, CD201, or CD36 to verify the selected subpopulations of ASCs. We detected no CD34-CD36 double-positive population, but CD34(+)-CD36(-) and CD34(-)CD36(+) subpopulations, both of which are positive for the 3 main MSC markers, CD73, CD90, and CD105. All other detected subpopulations also co-expressed the 3 main MSC markers, and therefore fulfill the minimal phenotypic criteria for the definition of cultured MSCs. Our study demonstrates the first comprehensive phenotypic characterization of ASCs and clearly highlights donor-specific variability in ASC preparations.
    Stem cells and development 08/2012; · 4.15 Impact Factor
  • Source
    Article: Neurodegeneration in ataxia telangiectasia: what is new? What is evident?
    [show abstract] [hide abstract]
    ABSTRACT: This article summarizes evident and recent findings on the characteristics of the neurological phenotype in ataxia telangiectasia (AT), reviews neuropathological and neuroradiological findings, and outlines therapeutic treatment options. In addition, this review offers an overview of current hypotheses on mechanisms of neurodegeneration in AT and discusses their relevance in clinical neurology. The obvious features of neurodegeneration in AT-cerebellar ataxia and dysarthia-are accompanied by a variety of further disabling disease symptoms. Review of the literature outlines a complex pattern of central nervous degeneration in AT that might have been underestimated so far. Neurodegeneration in AT is closely related to the absence or partial lack of the ataxia telangiectasia-mutated (ATM) kinase. ATM is a central player in maintaining cellular homeostasis. Systemic review of the literature reveals a subset of cellular targets hypothesized to count responsible for degeneration in ATM-deficient neurons. Further systematic cliniconeurological, pathoanatomical, and neuroradiological studies are required to understand the structural basis of this neurodegenerative disease. This better understanding has implications for the treatment of AT patients. Second, biochemical and molecular biological studies aimed at deciphering the pathomechanisms of this progressive disorder are necessary for the development of promising future therapies.
    Neuropediatrics 05/2012; 43(3):119-29. · 0.94 Impact Factor
  • Article: Early impact of smoking on lung function, health, and well-being in adolescents.
    [show abstract] [hide abstract]
    ABSTRACT: Smoking is the single most important risk factor for the development of chronic obstructive pulmonary disease, and more than 80% of adult smokers started smoking before the age of 20. The aim of our study was to evaluate the early impact of smoking on lung function, health, and well-being in adolescents. Twenty-four non-smokers (10 male, 14 female, mean age 17.6 years) and 24 smokers (mean of 3.5 pack-years; 15 male, 9 female, mean age 17.8 years) were compared in terms of lung function, bronchial hyperreactivity (BHR), levels of exhaled carbon monoxide (eCO), exhaled nitric oxide (eNO), and blood counts. A questionnaire containing items from the ISAAC study was used to detect differences in health and well-being. There were no significant differences in lung function values between non-smokers and smokers (VC 95% vs. 103%, FEV(1) 106% vs. 116%, FEV(1) %/VC MAX 94.6% vs. 95.2%), whereas BHR significantly differed (P < 0.05). Furthermore, significant differences were found for eCO, eNO, Hb, leukocytes, and neutrophils. Health and well-being in terms of sleep and physical activity were significantly worse in smokers. Our results suggest an early impact of smoking on health after as few as 3.5 pack-years. Early signs of smoking are an increase in BHR, changes in blood count and a decrease of eNO even before changes in lung function become apparent.
    Pediatric Pulmonology 12/2011; 47(7):692-9. · 2.53 Impact Factor
  • Article: New insights into epithelial differentiation of human adipose-derived stem cells.
    [show abstract] [hide abstract]
    ABSTRACT: Although many studies using stem cells as therapeutic agents after renal failure have been published in recent years, our knowledge of the factors involved and the cellular mechanisms underlying their beneficial effect on organ regeneration is incomplete. A growing insight into these interactions would help to utilize the biological potential of stem cells for therapeutic approaches. It is here hypothesized that soluble factors released by tubular epithelial cells (TECs) induce epithelial differentiation in adipose-derived adult mesenchymal stem cells (ASCs). ASCs were therefore cultured in conditioned medium (CM) derived from TECs and the changes in expression genes towards an epithelial pattern were determined by microarray and qPCR analyses. The changes in gene expression were evaluated using Affymetrix HG-U133 Plus 2.0 arrays. Microarray-based screening revealed 117 genes differentially expressed in a significant manner after short-time incubation (3 days) of ASCs with CM, and four of these were solute carriers (SLCs). Changes in mRNA expression of these SLCs were verified by qPCR at several time points, additionally with four stem cell factors and five epithelial markers. qPCR analyses showed that expression of three of the SLCs rose significantly, whereas three of the four stem cell markers analysed decreased during 7 days of CM incubation. Moreover, a robust expression of three characteristic epithelial markers (cytokeratin 18, ZO-1 and ZO-2) was observed after 17 days. These changes in the expression patterns strongly indicate differentiation towards the epithelial lineage. The capability of ASCs to differentiate into epithelial cells may be important in organ repair mechanisms. Copyright © 2011 John Wiley & Sons, Ltd.
    Journal of Tissue Engineering and Regenerative Medicine 12/2011; · 3.28 Impact Factor
  • Article: Comparison of cytokine levels from undiluted vitreous of untreated patients with retinal vein occlusion.
    [show abstract] [hide abstract]
    ABSTRACT: Purpose:  To compare cytokines in undiluted vitreous of treatment-naïve patients with macular oedema without vitreomacular traction secondary to branch (BRVO), central (CRVO) and hemi-central (H-CRVO) retinal vein occlusion. Methods:  Ninety-four patients (median age 72 years, 42 men) underwent an intravitreal combination therapy, including a single-site 23-gauge core vitrectomy and the application of bevacizumab and dexamethasone due to vision-decreasing macular oedema. Among these were 43 patients with BRVO, 35 with CRVO and 16 patients with hemi-CRVO, which were distributed in a fresh or old retinal vein occlusion type (seven or more months after onset). Undiluted vitreous samples were analysed for interleukin 6 (IL-6), monocyte chemoattractant protein-1 (MCP-1) and vascular endothelial growth factor (VEGF-A) with cytometric BEAD assay. Vitreous samples from patients with idiopathic epiretinal membrane served as controls (n = 14). Results:  The mean cytokine values were highest in the CRVO group with IL-6 = 64.7 pg/ml (SD ± 115.8), MCP-1 = 1015.8 pg/ml (±970.1) and VEGF-A = 278.4 pg/ml (±512.8), followed by the H-CRVO group with IL-6 = 59.9 pg/ml (SD ± 97.5), MCP-1 = 938.8 pg/ml (±561.1) and VEGF-A = 211.5 pg/ml (±232.4). The BRVO group had IL-6 = 23.2 pg/ml (SD ± 48.8), MCP-1 = 602.6 pg/ml (±490.3) and VEGF-A = 161.8 pg/ml (±314.4). The values of MCP-1 and VEGF-A were significantly different for CRVO or H-CRVO versus BRVO. All values were significantly higher than in the control samples, which had 6.2 ± 3.4 pg/ml (IL-6), 253 ± 74 pg/ml (MCP-1) and 7 ± 4.9 pg/ml (VEGF-A). Within the old RVO type, only MCP-1 was significantly different for CRVO or H-CRVO versus BRVO. Conclusions:  Both inflammatory markers and VEGF-A were higher in CRVO and H-CRVO than in BRVO undiluted vitreous samples. It seems that monocyte recruitment to the vessel wall, which might underlie the importance of eosinophils in tissue remodelling after RVO, is of special interest owing to the significant difference in MCP-1 in the older RVO types.
    Acta ophthalmologica 11/2011; 90(2):e98-e103. · 2.44 Impact Factor
  • Article: Increased systemic elastase and C-reactive protein in aggressive periodontitis (CLOI-D-00160R2).
    [show abstract] [hide abstract]
    ABSTRACT: The inflammatory mediators, serum elastase and C-reactive protein (CRP), are associated with an increased risk for coronary heart disease. Thus, the aim of this study is to compare systemic inflammatory mediators in periodontally healthy controls (C), patients with untreated aggressive (AgP) and chronic (ChP) periodontitis. C [periodontal pocket probing depth (PPD)  <3.6 or <5 mm without bleeding (BOP), BOP < 10%], ChP (PDD ≥ 3.6 mm and probing attachment loss ≥5 mm at >30% of sites; age >35 years), and AgP (clinically healthy; PDD ≥ 3.6 mm at >30% of sites, bone loss ≥50% at ≥2 teeth; age ≤35 years) were examined clinically, and the body mass index was assessed. Blood was sampled for assessment of serum levels of elastase, CRP, lipopolysaccharide binding protein (LBP), interleukin (IL) 6, 8, and leukocyte counts. Thirty C, 31 ChP, and 29 AgP were analyzed. Elastase, CRP, LBP, and IL-6 levels were elevated in AgP compared to C (p < 0.013), whereas leukocyte counts and IL-8 were similar. Multiple regression analysis identified AgP (p < 0.001) and education level (p < 0.001) to explain 47% of the variation of elastase. AgP (p = 0.003), African origin (p = 0.006), female sex (p = 0.002), and BMI (p < 0.001) explained 39% of the variation of CRP. Serum elastase and CRP are significantly elevated in AgP compared to C. AgP patients exhibit a stronger systemic inflammatory burden than C patients.
    Clinical Oral Investigations 10/2011; 16(4):1199-207. · 2.36 Impact Factor
  • Article: During epithelial differentiation of human adipose-derived stromal/stem cells, expression of zonula occludens protein-1 is induced by a combination of retinoic acid, activin-A and bone morphogenetic protein-7.
    [show abstract] [hide abstract]
    ABSTRACT: Adipose-derived stromal/stem cells (ASC) possess a multilineage differentiation potential, can be used from an autologous origin, and are, therefore, attractive candidates for clinical applications to repair or regenerate damaged tissues and organs. Beside their well-known differentiation into cells of mesodermal origin, ASC are able to differentiate into cells of ecto- and endodermal origin. Previous studies have shown that all trans retinoic acid (ATRA) induces the expression of cytokeratin 18 (CK18), indicating the beginning of differentiation into the epithelial lineage. Nevertheless, ATRA does not induce the expression of other epithelial markers. Therefore, we tested the additional influence of two growth factors on the onset of epithelial differentiation of ASC. The cells were cultured with ATRA, Activin A (ActA) and bone morphogenetic protein-7 (BMP-7), either alone or in combination. Differentiation into the epithelial lineage was assessed by the expression of the characteristic epithelial markers CK18 and zonula occludens protein 1 (ZO-1) using Western blot, immunofluorescence staining and polymerase chain reaction (PCR) analysis. The mixture of all three factors induced epithelial differentiation of ASC without enhancing cell proliferation. Upon induction, the ASC showed phenotypic changes consistent with an epithelial phenotype. The addition of the growth factors ActA and BMP-7 enhanced the inductive effect of ATRA, as shown by the de novo expression of ZO-1 in addition to CK18 expression. Our study highlights the onset of the epithelial differentiation of ASC induced by culture with a combination of ATRA, ActA and BMP-7.
    Cytotherapy 09/2011; 14(1):61-9. · 3.63 Impact Factor
  • Article: Workshop report: European workshop on ataxia-telangiectasia, Frankfurt, 2011.
    Stefan Zielen, Ralf Schubert
    [show abstract] [hide abstract]
    ABSTRACT: Ataxia-telangiectasia (A-T) is a devastating human recessive disorder characterized by progressive cerebellar ataxia, immunodeficiency, chromosomal instability, and cancer susceptibility. The European Workshop on Ataxia-Telangiectasia 2011 in Frankfurt focused on status quo of patient care and future clinical research directions. In Europe, approximately 600 patients are registered and many national websites have been established. During the meeting, guidelines of patient care were discussed and all participants agreed to build up an European A-T research network in near future to bring basic research and new therapies into clinical applications.
    Journal of neurogenetics 07/2011; 25(3):78-81. · 0.73 Impact Factor
  • Source
    Article: Safety, tolerability, and impact on allergic inflammation of autologous E.coli autovaccine in the treatment of house dust mite asthma--a prospective open clinical trial.
    [show abstract] [hide abstract]
    ABSTRACT: Asthma is increasing worldwide and results from a complex immunological interaction between genetic susceptibility and environmental factors. Autovaccination with E. coli induces a strong TH-1 immune response, thus offering an option for the treatment of allergic diseases. Prospective open trial on safety, tolerability, and impact on allergic inflammation of an autologous E.coli autovaccine in intermittent or mild persistent house dust mite asthma. Determination of exhaled nitric monoxide (eNO) before and after bronchial mite challenge initially and after nine months of autovaccination. In nine subjects and a total of 306 injections, we observed 101 episodes of local erythema (33.3%; median of maximal diameter 2.5 cm), 95 episodes of local swelling (31.1%; median of maximal diameter 3 cm), and 27 episodes of local pain (8.8%). Four subjects reported itching at the injection site with a total of 30 episodes (9.8%). Median eNO increase after autovaccination was significantly smaller (from 27.3 to 33.8 ppb; p = 0.334) compared to initial values (from 32.6 to 42.2 ppb; p = 0.046) (p = 0.034). We observed no serious adverse events. All organ functions (inclusive electrocardiogramm) and laboratory testing of the blood (clinical chemistry, hematology) and the urine (screening test, Β-microglobuline) were within normal limits. Vital signs undulated within the physiological variability. The administration of autologous autovacine for the treatment of house dust mite asthma resulted in a reduction of the eNO increase upon bronchial mite challenge. In nine subjects and 306 injections, only a few mild local reactions and no systemic severe adverse events were observed. EudraCT Nr. 2005-005534-12ClinicalTrials.gov ID NCT00677209.
    BMC Complementary and Alternative Medicine 06/2011; 11:45. · 2.24 Impact Factor
  • Source
    Article: Revaccination of children after completion of standard chemotherapy for acute lymphoblastic leukaemia: a pilot study comparing different schedules.
    [show abstract] [hide abstract]
    ABSTRACT: Given that a significant proportion of children with acute lymphoblastic leukaemia (ALL) lose immune protection to tetanus, diphtheria, and poliomyelitis, revaccination is indicated after chemotherapy. Our randomized pilot study comparing different revaccination schedules suggests that children with ALL might be revaccinated with non-live vaccines as early as 3 months after chemotherapy.
    British Journal of Haematology 01/2011; 152(6):754-7. · 4.94 Impact Factor
  • Article: Omega-3 polyunsaturated fatty acids and bronchial inflammation in grass pollen allergy after allergen challenge.
    [show abstract] [hide abstract]
    ABSTRACT: RATIO: Asthma is a major public health problem, with bronchial inflammation as the therapeutic target. The role of dietary fish oil derived polyunsaturated fatty acids (PUFAs) in allergic inflammation is controversial. Most asthmatics suffer from mild disease and non-pharmacologic interventions are attractive. This study investigates the anti-inflammatory potential of nutritional PUFAs in an experimentally induced bronchial inflammation. We examined 38 grass pollen allergic asthmatics and 19 controls. History of dietary PUFA intake was compared with levels of PUFAs in erythrocyte membranes, and stratified according to low (25th quartile; Q25) and high (75th quartile; Q75) ratios of omega-3 (n-3) to omega-6 (n-6) PUFAs as a surrogate for anti-inflammatory (Q75) or proinflammatory (Q25) effects. Bronchial inflammation was simulated with one-step inhalation of grass pollen. Bronchial response (exhaled nitric monoxide, eNO as surrogate for inflammation, decrease of FEV(1)) was correlated with levels of PUFAs in erythrocyte membranes. Ratios of n-3/n-6 PUFA were significantly lower in asthmatics than in healthy controls. Levels of eNO were significantly higher in Q25 asthmatics than in Q75 asthmatics (p = 0.040). There was a trend of higher bronchial hyperreactivity in Q25 asthmatics (median PD(20) 0.27 vs. 0.14; n.s.), induced by specific bronchial challenge with grass pollen (FEV(1) decrease 16.7 vs. 23.1%; n.s.). When stratifying for erythrocyte membrane PUFA content as a surrogate for alimentary intake, we found mild effects on bronchial allergic inflammation. Future intervention studies with pharmacological PUFA doses appear suitable to clarify dietary PUFA role as an adjunctive intervention to the established treatment of asthma. ClinicalTrials.gov No. NCT00519740.
    Respiratory medicine 12/2010; 104(12):1793-8. · 2.33 Impact Factor
  • Article: Sputum biomarker profiles in cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) and association between pulmonary function.
    [show abstract] [hide abstract]
    ABSTRACT: Lung diseases like cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) are associated with chronic airway inflammation. The aim of our study was to compare a complex biomarker profile in order to characterize specific inflammatory patterns in sputum of patients with CF and COPD. Induced sputum samples of 19 CF-, 26 COPD patients and 21 healthy controls were analyzed for concentrations of IL-1beta, IL-2, IL-6, IL-8, IL-13, IP-10, MCP-1, IFN-gamma and TNF-alpha using the new cytometric bead array (CBA) technology. Significant differences in airway biomarker profiles of CF and COPD were detected. Patients with CF showed a significant increase in IL-1beta, IL-6, IL-8, IL-13, TNF-alpha, IFN-gamma and MCP-1. COPD patients showed an increase in IL-6, IL-8, IL-13 and MCP-1 compared to healthy controls. CF and COPD compared to each other exhibited differences in IL-1beta, IL-2, IL-8, TNF-alpha, IFN-gamma and MCP-1 levels. Significant correlations between the parameters of lung function and sputum biomarker levels were found. Analyzing induced sputum allows characterization of specific airway biomarker profiles in CF and COPD and can be related to the clinical status of the patient. CBA of induced sputum seems to be a pivotal tool to characterize pulmonary inflammation.
    Cytokine 02/2010; 50(2):152-7. · 3.02 Impact Factor
  • Article: Reactive oxygen species abrogate the anticarcinogenic effect of eicosapentaenoic acid in Atm-deficient mice.
    [show abstract] [hide abstract]
    ABSTRACT: Recent studies have demonstrated that n-3 polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) are able to suppress cell proliferation and inhibit tumor growth. The objective of our study was to investigate the influence of a high dose EPA on the development of the tumor phenotype in ataxia-telangiectasia mutated (Atm)-deficient mice, a genetic cancer model that is associated with increased levels of oxidative stress. We analyzed toxicity, proliferation, cell-cycle progression, and apoptosis of EPA in vitro and latency to tumorigenesis in vivo. Because of the impact of reactive oxygen species (ROS) on the tumor incidence in ataxia telangiectasia (AT), we further analyzed the effect of EPA on the generation of ROS and oxidative DNA damage (ODD). EPA effectively inhibited proliferation, altered cell-cycle progression, and induced apoptosis of tumor cells (AT-4). EPA showed no effect on the latency to tumorigenesis in Atm-deficient mice. EPA treatment was accompanied by a significant increase of ROS and ODD. Our results demonstrate the antiproliferative effect of EPA on tumor cells by alteration of cell-cycle progression and induction of apoptosis in vitro. On the other hand, EPA treatment of Atm-deficient mice led to the formation of ROS and accumulation of ODD that might have abrogated the anticarcinogenic effect caused by EPA.
    Nutrition and Cancer 01/2010; 62(5):584-92. · 2.78 Impact Factor
  • Article: Predicting short term response to anti-inflammatory therapy in young children with asthma.
    [show abstract] [hide abstract]
    ABSTRACT: Currently available anti-inflammatory treatment for young children with asthma includes inhaled corticosteroids (ICS) and the leukotriene receptor antagonist (LTRA) montelukast. To evaluate potential biomarkers of predicting short-term (6-week) response to ICS and LTRAs in children with asthma. A total of 102 children aged 4 to 7 years with episodic asthma were enrolled in an open labelled single-centre study. Biomarkers and asthma characteristics were evaluated as predictors of treatment. Of 102 patients 45 became symptomatic during observation and were randomised to treatment either to montelukast or fluticasone for 6 weeks. Forced Expiratory Volume in one second (FEV1) increased with both treatments: FEV1 at randomisation was 90.2% and after therapy 106.8% with fluticasone vs. 90.8% and 103.7% for montelukast, respectively, showing that montelukast and fluticasone were equally effective in this age group (p = 0.44). Strong correlations to a favourable treatment response were pre-bronchodilatory FEV1 (p < 0.001) and airway reversibility (p = 0.04) at time of randomisation. None of the other biomarkers (methacholine testing, exhaled nitric oxide [eNO], presence of allergy, total Immunoglobulin E [IgE], cumulative specific IgE, eosinophils and parental smoking) were predictive. Despite the small sample size and the open-label design, the study suggests that the use of pre-bronchodilatory FEV1 and airway reversibility appears to be a good indicator of short-term anti-inflammatory therapy in young children with asthma.
    Current Medical Research and Opinion 12/2009; 26(2):483-92. · 2.38 Impact Factor
  • Article: Human adipose-derived mesenchymal stem cells in vitro: evaluation of an optimal expansion medium preserving stemness.
    [show abstract] [hide abstract]
    ABSTRACT: The potential of cultured adipose-derived stem cells (ASC) in regenerative medicine and new cell therapeutic concepts has been shown recently by many investigations. However, while the method of isolation of ASC from liposuction aspirates depending on plastic adhesion is well established, a standard expansion medium optimally maintaining the undifferentiated state has not been described. We cultured ASC in five commonly used culture media (two laboratory-made media and three commercially available media) and compared them with a standard medium. We analyzed the effects on cell morphology, proliferation, hepatocyte growth factor (HGF) expression, stem cell marker profile and differentiation potential. Proliferation was measured with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and a fluorescent assay. Release of HGF was assessed by an immunoassay. Expression of characteristic stem cell-related transcription factors and markers was evaluated by quantitative polymerase chain reaction (qPCR) (Nanog, Sox-2, Rex-1, nestin and Oct-4) and flow cytometry (CD44, CD73, CD90, CD105 and CD166), and differentiation was shown by adipogenic medium. The morphology and expansion of ASC were significantly affected by the media used, whereas none of the media influenced the ASC potential to differentiate into adipocytes. Furthermore, two of the media induced an increase in expression of transcription factors, an increased secretion of HGF and a decrease in CD105 expression. Culture of ASC in one of these two media before using the cells in cell therapeutic approaches may have a benefit on their regenerative potential.
    Cytotherapy 11/2009; 12(1):96-106. · 3.63 Impact Factor
  • Article: Extracerebellar MRI-lesions in ataxia telangiectasia go along with deficiency of the GH/IGF-1 axis, markedly reduced body weight, high ataxia scores and advanced age.
    [show abstract] [hide abstract]
    ABSTRACT: Ataxia telangiectasia (AT) is a rare autosomal recessive disorder characterized by progressive ataxia, neurodegeneration, immunodeficiency, and cancer predisposition. Pathoanatomical studies reported a degeneration of cerebellar Purkinje cells as the striking feature of the disease. Although recent studies suggested the involvement of extracerebellar structures such as the brainstem and basal ganglia, this has rarely been studied in human AT. Thus, we performed a detailed cliniconeuroradiological investigation of 11 AT patients, aged 8 to 26 years by collecting clinical neurological data, ataxia scores, growth status, body mass index (BMI), growth hormone (GH), and insulin-like-growth factor 1 (IGF-1) and correlated them to extracerebellar neuroimaging findings in human AT. Neuroimaging was done by cranial and spine magnetic resonance imaging (MRI) with T1- and T2-weighted spin-echo and fluid attenuated inversion recovery sequences. We compared clinical and neuroradiological findings of six patients with IGF-1 levels and BMI below the third percentile to five patients with normal IGF-1 serum levels and BMI above the third percentile. Three of the six first mentioned patients older than 20 years and two patients older than 12 years showed noticeable high Klockgether ataxia scores above 25 points. Three of these patients presented with marked hyperintense lesions in the cerebral white matter of T2-weighted MR images. Interestingly, all six patients suffered from marked spinal atrophy. Two of the patients presented with severe extra-pyramidal symptoms, but only one patient showed associated MRI abnormalities of the basal ganglia. MRI in patients with normal IGF-1 levels showed the expected cerebellar lesions in four patients, whereas spinal atrophy was found only in two patients. There was no affection of the cerebral white matter or basal ganglia in this group. We conclude that central cerebral white matter affection, spinal atrophy, and extrapyramidal symptoms are more often present in patients with pronounced deficiency of the GH/IGF-1 axis accompanied by markedly reduced body weight and high ataxia scores. This may point to a major role of IGF-1 and nutritional status in neuroprotective signaling.
    The Cerebellum 11/2009; 9(2):190-7. · 3.21 Impact Factor
  • Source
    Article: Simultaneous detection of ERK-, p38-, and JNK-MAPK phosphorylation in human adipose-derived stem cells using the Cytometric Bead Array technology.
    [show abstract] [hide abstract]
    ABSTRACT: Despite expanded research in stem cell biology, little is known about the mechanisms underlying migration, growth, and differentiation of adipose-derived adult mesenchymal stem cells (ASC). The simultaneous measurement of intracellular pathways opens new avenues to gain further insights in these processes. We used the Cytometric Bead Array (CBA) Flex Set technology to simultaneously analyze protein phosphorylation after stimulation of ASC and compared the results with data generated by corresponding Western blots. Signal transduction of ASC was stimulated by epidermal growth factor (EGF) and analyzed by determining phosphorylation of mitogen-activated protein kinases (MAPKs) ERK, p38, and JNK by Western blotting and CBA. After incubation with EGF, all MAPKs were significantly but differentially phosphorylated depending on time and dose. Furthermore, the ERK-response was abolished by EGF-R antagonist AG 1478 and kinase inhibitor PD98059, whereas p38 and JNK were only inhibited by AG1478. The stimulation and inhibition profiles between the two assays were highly comparable and the data were significantly correlated. In the present study we demonstrated that the CBA technology offers a reliable and convenient method for multiplexing of phospho-proteins in the evaluation of signal transduction pathways of adipose-derived mesenchymal stem cells.
    Journal of immunological methods 10/2009; 350(1-2):200-4. · 2.35 Impact Factor

Institutions

  • 2002–2013
    • Goethe-Universität Frankfurt am Main
      • • Klinik für Dermatologie, Venerologie und Allergologie
      • • Zentrum der Inneren Medizin
      Frankfurt am Main, Hesse, Germany
  • 2010
    • Sydney Children's Hospital
      Sydney, New South Wales, Australia
  • 2006
    • Georg-August-Universität Göttingen
      Göttingen, Lower Saxony, Germany
  • 2002–2005
    • Rheinische Friedrich-Wilhelms-Universität Bonn
      • Zentrum für Innere Medizin
      Bonn, North Rhine-Westphalia, Germany
  • 2004
    • Comprehensive Cancer Centers of Nevada
      Las Vegas, NV, USA