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Biomedical subjects

Peter Rieckmann

Publications and source records attributed to Peter Rieckmann.

At least 19 recordsLinked to original sources
PubMed2006

Interferon-beta is a potent inducer of interferon regulatory factor-1/2-dependent IP-10/CXCL10 expression in primary human endothelial cells.

Most virus-infected cells release interferon-beta (IFN-beta) as a powerful inducer of antiviral defense. Endothelial cells tightly regulate local immune cell recruitment by expression of adhesion molecules and chemokines. Here, we studied the transcriptional regulation of IFN-beta-induced chemokine expression in primary human endothelial cells. IFN-beta moderately increased monocyte chemoattractant protein-1/CCL2 and potently raised IFN-gamma-inducible protein-10/CXCL10 mRNA steady-state levels and protein release, while no effect was detected on various other chemokines. As shown by transient transfections, induction of CXCL10 expression depends on an IFN-stimulated response element (ISRE) within the CXCL10 promoter. A double point mutation of the putative IFN regulatory factor (IRF)-1/2 binding site within this ISRE motif abolished IFN-beta-induced promoter activity. In electrophoretic mobility shift assays, this ISRE motif showed a basal IRF-2 and an IFN-beta-inducible IRF-1 and augmented IRF-2 binding. Furthermore, stimulation with IFN-beta induced a rapid nuclear translocation of signal transducer and activator of transcription 1 (STAT1) and STAT2 and their transient binding to a gamma-activated site within the CCL2 promoter. The kinetics of transient STAT1 binding to this gamma-activated site element correlated with the amount of Y701-phosphorylated nuclear STAT1, while S727-phosphorylated nuclear STAT1 remained stable over 24 h after stimulation. Therefore, IFN-beta potently induces endothelial chemokine expression at the transcriptional level.

Active Transport, Cell Nucleus↗
PubMed2006

Glioblastoma multiforme with oligodendroglial component (GBMO): favorable outcome after post-operative radiotherapy and chemotherapy with nimustine (ACNU) and teniposide (VM26).

BACKGROUND: The presence of an oligodendroglial component within a glioblastoma multiforme (GBM) is considered a prognostically favorable factor, but the clinical outcome of patients with glioblastoma multiforme with oligodendroglial component (GBMO) after combined post-operative radiotherapy and chemotherapy has rarely been reported. METHODS: We analyzed overall and progression-free survival in a group of ten consecutive patients initially diagnosed with GBMO between 1996 and 2004 (4.2% of all GBM patients). Median (range) age was 54 (34-73) years, 90% were resected and median radiotherapy dose was 54 (45-60.6) Gy. 80% of patients received post-operative chemotherapy with nimustine (ACNU) and VM26 (teniposide) for a median of 3.5 (1-6) cycles, the remainder were treated with post-operative radiotherapy alone. All specimens were reviewed by an experienced neuropathologist. RESULTS: Neuropathological re-evaluation revealed GBM with an oligodendroglial component of 30% or less in five cases, predominant oligoastrocytic tumors with focal areas of GBM in four patients and WHO grade III oligoastrocytoma with questionable transition to GBM in one patient. Four of ten patients were alive at at 40, 41, 41 and 82 months. The median overall survival (Kaplan-Meier) was 26 months, the 2-year survival rate was 60% (progression-free survival: 9.8 months and 40%, respectively). CONCLUSION: In conclusion, patients with GBMO treated with post-operative radiotherapy and chemotherapy with ACNU/VM26 had a better prognosis than reported for GBM in modern chemoradiation series.

Adult↗
PubMed2006

Frequency analysis of HLA-B7-restricted Epstein-Barr virus-specific cytotoxic T lymphocytes in patients with multiple sclerosis and healthy controls.

The Epstein-Barr virus (EBV) has been implicated in the pathogenesis of multiple sclerosis (MS), however, the mechanisms by which EBV may be involved in MS are unknown. We here have investigated the frequency of EBV-specific cytotoxic T lymphocytes (CTL) in human leukocyte antigen (HLA)-B7(+) patients with MS and healthy controls using enzyme-linked immunospot assays and seven previously characterized HLA-B7-restricted immunogenic EBV peptides. Overall, there were no significant differences in the frequency of EBV-specific CTL between both groups. These data do not support the hypothesis that EBV could play a role in MS by inducing quantitatively altered EBV-specific CTL responses. Other pathogenic mechanisms for EBV in MS remain to be elucidated.

Adult↗
PubMed2006

[Escalating immunomodulatory therapy of multiple sclerosis. Update (September 2006)].

The updated recommendations presented here reflect new developments in the diagnostic work-up and immunotherapy of multiple sclerosis (MS) as well as optimization of medical care for MS patients. Monoclonal antibodies provide considerable improvement of treatment, but their use in basic therapy is restricted by their side effect profile. Thus, for the time being, natalizumab is only approved for monotherapy after basic treatment has failed or for rapidly progressive relapsing-remitting MS. In contrast, long-term data on recombinant beta-interferons and glatiramer acetate (Copaxone) show that even after several years no unexpected side effects occur and that a prolonged therapeutic effect can be assumed which correlates with the dose or frequency of treatment. Recently IFN-beta1b (Betaferon) was approved for prophylactic treatment after the first attack (clinically isolated syndrome, CIS). During treatment with beta-interferons, neutralizing antibodies can emerge with possible loss of effectivity. In contrast, antibodies play no role in treatment with glatiramer acetate. During or after therapy with mitoxantrone, serious side effects (cardiomyopathy, acute myeloid leukemia) appeared in 0.2-0.4% of cases. Plasmapheresis is limited to individual curative attempts in escalating therapy of a severe attack. According to the revised McDonald criteria, the diagnosis of MS can be made as early as the occurrence of the first attack (CIS). Recommendations for optimized care of MS patients are also new, thus implementing a resolution of the European Parliament.

Antibodies, Monoclonal↗
PubMed2006

Socio-economic aspects of neuroimmunological diseases.

Neuroimmunological diseases often have a chronic course and a high socio-economic impact, as most of them occur in younger patients and result in progressing disability and loss of work force. Although for many conditions different treatment strategies are available no sufficient data exist to give a reasonable account on the cost effectiveness of individual therapies. Treatment decision should primarily be guided by evidence from high quality clinical studies and-if available-from direct head-to-head trials and cost-effectiveness analysis.

Autoimmune Diseases of the Nervous System↗
PubMed2006

Isolation and culture of microvascular endothelial cells from gliomas of different WHO grades.

Gliomas are the most common intrinsic brain tumors. The degree of vascularization corresponds to malignancy and is related to prognosis. In order to retrieve information about tumor behavior in situ, the use of primary tissue material for experiments is advantageous. With increasing evidence for the importance of microenvironment and vascularization in tumor biology, we concentrated on the isolation of endothelial cells (EC) from primary tumor material to investigate the role of endothelium within tumor tissue. We developed a method for isolation and purification of tumor-derived endothelial cells. EC were isolated and cultivated from normal brain using tissue digestion and Percoll density gradient centrifugation resulting in a <95% of EC culture. For isolation of EC from gliomas of different malignancy grades a combination of tissue digestion, Percoll gradient centrifugation and magnetic bead sorting by anti-CD31, -VE-Cadherin and -CD 105 was employed. This approach provided a purity of <98%. Cells were classified and characterized by testing expression of CD105, CD31, VE-Cadherin, vWF, UEA-1 and measuring DiI-Ac-LDL-uptake. To exclude contamination, staining and negative selection with anti-SMA, -GFAP, and -CD68 was performed. Tumors were histopathologically diagnosed according to WHO classification. We isolated EC from normal brain (NBEC, n = 11), low-grade gliomas WHO II (LGEC, n = 22), and high-grade gliomas WHO III & IV (HGEC, n = 11). There were no clear differences in EC morphology between the different tumor grades. However, a significantly higher proliferation rate of HGEC compared to LGEC was observed as well as distinctive antigen expression. Already in early passages isolated EC showed a rapid change in antigen expression indicating a phenotypic shift under culture conditions. We could establish a protocol for reliable and reproducible isolation and culture of EC from gliomas with different WHO grading. In first phenotypical and functional analyses, NBEC, LGEC and HGEC show remarkable differences. EC from all tumors could be grown in culture. However, passage related changes of EC phenotype demand very early passages to work with.

Brain Neoplasms↗
PubMed2006

Regulation of human endogenous retrovirus W protein expression by herpes simplex virus type 1: implications for multiple sclerosis.

The multiple sclerosis-associated retrovirus (MSRV), originally identified in cell cultures from patients with multiple sclerosis (MS), is closely related to the human endogenous retrovirus family W (HERV-W). Recently, HERV-W gag and env protein expression was demonstrated in MS lesions in situ. Here, the authors show that HERV-W gag and env proteins are induced by herpes simplex virus type 1 (HSV-1) in neuronal and brain endothelial cells in vitro. The transactivation of HERV-W proteins by HSV-1 could enhance their potential oligodendrotoxic and immunopathogenic effects, representing a mechanism by which HSV-1, and possibly also other herpesviruses associated with MS, may be linked to the pathogenesis of this disease.

Endogenous Retroviruses↗
PubMed2005

Subcutaneous interferon-beta injections in patients with multiple sclerosis initiate inflammatory skin reactions by local chemokine induction.

Subcutaneous Interferon-beta (IFN-beta) injections for the treatment of multiple sclerosis (MS) frequently cause inflammatory injection site reactions. To study the role of chemokines we obtained skin biopsies from 7 MS patients 24 h after injection. At the IFN-beta but not at the contralateral placebo injection sites, we observed strong IP-10/CXCL10 and moderate MCP-1/CCL2 expression associated with extensive perivascular, highly CXCR3-positive T cell and macrophage infiltrates. Primary human skin cells displayed a comparable pattern of chemokine induction after stimulation with IFN-beta in vitro. IFN-beta may therefore trigger inflammatory skin reactions through local chemokine induction followed by rapid immune cell extravasation.

Antigens, CD↗
PubMed2005

Association of a common polymorphism in the promoter of UCP2 with susceptibility to multiple sclerosis.

Uncoupling protein 2 (UCP2) is a member of the mitochondrial proton transport family that uncouples proton entry to the mitochondria from ATP synthesis. UCP2 expression levels have been linked to predisposition to diabetes and obesity. In addition, UCP2 prevents neuronal death and injury. Here we show that the common -866G/A promoter polymorphism is associated with susceptibility to multiple sclerosis (MS) in the German population. We analysed altogether 1,097 MS patients and 462 control subjects from two cohorts and found that the common G allele is associated with disease susceptibility (p = 0.0015). The UCP2 -866G allele is correlated with lower levels of UCP2 expression as shown here in vitro and in vivo. Thus, UCP2 promoter polymorphism may contribute to MS susceptibility by regulating the level of UCP2 protein in the central nervous and/or the immune systems.

Adolescent↗
PubMed2005

A PD-1 polymorphism is associated with disease progression in multiple sclerosis.

T cells are considered to play a pivotal role in orchestrating the self-reactive immune responses in multiple sclerosis (MS). Programmed death 1 (PD-1) is a member of the B7/CD28 superfamily of costimulatory molecules exerting inhibitory functions on T cells. Recently, an intronic 7146G/A polymorphism within the PD-1 gene was described and suggested to be associated with autoimmunity. We investigated whether this genetic polymorphism is a genetic modifier for risk and progression of MS. Blood samples from 939 German MS patients (mean age, 39 years; range, 13-71; 566 patients [60%] with relapsing-remitting MS, 279 (30%) with secondary, and 94 (10%) with primary progressive MS) and 272 healthy white controls were tested. Genotyping was performed by polymerase chain reaction and restriction enzyme digestion; results were confirmed by automatic sequencing. A significant association of the mutated allele with a progressive disease course was detected (44% 7146G vs 56% 7146A, chi(2) p = 0.002). Consequences of the PD-1 mutation for T-cell function were assessed ex vivo in some patients using microsphere-stimulated peripheral blood lymphocytes and purified CD4 cells. Importantly, PD-1-mediated inhibition of T-cell cytokine secretion (interferon-gamma) is impaired in patients carrying the PD-1 polymorphism. In conclusion, our data suggest that PD-1 polymorphism is a genetic modifier of the progression of MS, possibly through inducing a partial defect in PD-1-mediated inhibition of T-cell activation.

Adolescent↗
PubMed2005

Soluble vascular cell adhesion molecule (VCAM) is associated with treatment effects of interferon beta-1b in patients with secondary progressive multiple sclerosis.

BACKGROUND: Subcutaneous IFNbeta-1b (Betaferon) is an established immunomodulatory treatment for relapsing remitting MS and active secondary progressive multiple sclerosis (SPMS). It modulates cytokine and adhesion molecule expression but long term in vivo effects of IFNbeta-1b on the immune system are not known in multiple sclerosis. OBJECTIVE: To address the effects of IFNbeta-1b on serum levels for soluble adhesion molecules and cytokine receptors from MS patients. METHODS: Serial blood samples were obtained from 40 patients of the frequent MRI subgroup (20 patients each from the placebo and the IFNbeta-1b treatment group), participating in the European multi-center clinical trial with IFNbeta-1b for secondary progressive MS, at regular intervals for up to 36 months. Soluble adhesion molecules (sVCAM, sICAM-1, sL-Selectin) as well as TNF-receptor I and II were analysed in the serum of patients by enzyme linked immunosorbent assays (ELISAs). Monthly brain MRI was performed in 34 of these patients (16 patients from the placebo and 18 from the IFNbeta-1b group) during months 1-6 and 19-24 to monitor disease activity as assessed by newly occurring gadolinium (Gd) enhancing lesions. RESULTS: An early and significant increase in sVCAM and sTNF-RII serum levels was detected in 16 out of 20 patients (80 %) treated with subcutaneous IFNbeta-1b already at month 1 but was absent in all but one patient during placebo treatment (p < 0.01). Raised sVCAM and TNF RII serum levels during months 1-6 inversely correlated with less MRI activity in the 19-24 months treatment interval in the IFNa-1b treatment group ( p = 0.0093 for TNF-RII; p = 0.047 for VCAM). CONCLUSIONS: sVCAM and sTNF RII levels in the serum of SPMS patients are increased during IFNbeta-1b therapy and may at least in part explain some of the treatment effects, like reduced immune cell transmigration.

Adult↗
PubMed2005

Human endogenous retrovirus (HERV)-W ENV and GAG proteins: physiological expression in human brain and pathophysiological modulation in multiple sclerosis lesions.

Antigen expression of a human endogenous retrovirus family, HERV-W, in normal human brain and multiple sclerosis lesions was studied by immunohistochemistry by three independent groups. The HERV-W multicopy family was identified in human DNA from the previously characterized multiple sclerosis-associated retroviral element (MSRV). A panel of antibodies against envelope (ENV) and capsid (GAG) antigens was tested. A physiological expression of GAG proteins in neuronal cells was observed in normal brain, whereas there was a striking accumulation of GAG antigen in axonal structures in demyelinated white matter from patients with MS. Prominent HERV-W GAG expression was also detected in endothelial cells of MS lesions from acute or actively demyelinating cases, a pattern not found in any control. A physiological expression of ENV proteins was detected in microglia in normal brain; however,a specific expression in macrophages was apparently restricted to early MS lesions. Thus, converging results from three groups confirm that GAG and ENV proteins encoded by the HERV-W multicopy gene family are expressed in cells of the central nervous system under normal conditions. Similar to HERV-W7q ENV (Syncitin), which is expressed in placenta and has been shown to have a physiological function in syncytio-trophoblast fusion, HERV-W GAG may thus also have a physiological function in human brain. This expression differs in MS lesions, which may either reflect differential regulation of inherited HERV-W copies, or expression of "infectious" MSRV copies. This is compatible with a pathophysiological role in MS, but also illustrates the ambivalence of such HERV antigens, which can be expressed in cell-specific patterns, under physiological or pathological conditions.

Adult↗
PubMed2005

Neurodegeneration and clinical relevance for early treatment in multiple sclerosis.

The treatment of MS with immunomodulatory agents such as interferon beta and glatiramer acetate, early in the disease course, is increasingly recognized as benefiting patient outcome. MS is a chronic inflammatory disease of the central nervous system with morphological hallmarks of inflammation, demyelination, axonal loss and gliosis. While inflammation and demyelination induce neurological deficit, which is at least partly reversible, axonal loss beyond the threshold of compensation is always accompanied by irreversible clinical disease progression. These neuropathological findings suggest that, in addition to reducing the impact of inflammation, the ability to prevent axonal degeneration is a vital component of MS treatment. Approved immunomodulatory therapies shift immunological status from a pro-inflammatory response toward more beneficial anti-inflammatory conditions. Clinical studies also suggest that beta interferon helps to prevent, and may at least partially reverse, axonal injury. Future work in this area will be aided by using magnetic resonance imaging (MRI) to follow hypointense lesions and quantification of N-acetyl aspartate by MR spectroscopy, both of which are potential markers of structural damage. The urgent need to identify definitive markers of neuroprotection in humans remains. Such markers explain more about the underlying mechanisms of early MS pathophysiology.

Adjuvants, Immunologic↗
PubMed2004

Evaluation of diagnostic relevance of mRNA levels in peripheral blood: predictive value for mortality in hemodialysis patients.

In clinical practice, diagnosis and risk prediction are usually based on the analysis of serum or plasma proteins whereas gene expression analysis is not used on a routine basis. In order to compare the diagnostic and predictive relevance of serum protein and peripheral blood mRNA levels, we determined cytokine levels of end-stage renal failure patients undergoing hemodialysis. These patients face a high mortality mainly due to acceleration of atherosclerosis and subsequent severe vascular events. mRNA expression of the pro-inflammatory cytokine TNF alpha was significantly elevated in hemodialysis patients and further increased after 2 h of dialysis treatment. In contrast, gene expression of the anti-inflammatory cytokine TGF beta was significantly decreased. Patients who died during the observation period of 36 months had significantly increased mRNA levels of TNF alpha and decreased TGF beta mRNA expression at baseline. Survival analysis indicated that increased TNF alpha mRNA levels (P < 0.02) and TNF alpha/TGF beta mRNA ratios (P < 0.001) predict mortality. The corresponding cytokines in serum showed some association with disease, but serum concentrations neither changed during hemodialysis nor predicted mortality. This study shows that gene expression patterns of circulating leukocytes may present an important new diagnostic tool to predict clinical outcome in patients with inflammatory vascular diseases.

Adult↗
PubMed2004

Selective loss of regulatory T cells in thymomas.

Myasthenia gravis (MG) is the prime autoimmune manifestation of thymomas. We investigated the generation of T cells with a regulatory phenotype (T(R)) in thymomas with and without associated MG. In patients with MG(+) thymomas, maturation and export of T(R) cells but not of other T-cell subsets was significantly reduced. We conclude that imbalance between effector and regulatory T cells in thymomas may be involved in modulation of onset and/or severity of MG.

Adolescent↗
PubMed2004

Determination of ventricular diameters in multiple sclerosis patients with transcranial sonography (TCS)--a two year follow-up study.

CONTEXT: Brain atrophy is an indicator of diffuse brain pathology that appears even in the early stages of multiple sclerosis (MS). Magnetic resonance imaging (MRI) techniques used in clinical trials suggest a correlation between ventricular enlargement and axonal pathology and clinical disability in MS. OBJECTIVE: To evaluate by transcranial sonography (TCS) and MRI ventricular diameters in order to assess prospectively the development of brain atrophy in MS. SETTING: MS outpatient clinic of a university hospital. PATIENTS AND METHODS: 38 MS patients (27 females, 11 males) were followed up for 2 years. Ventricular diameters (third ventricle, right and left lateral ventricle) were determined by TCS at baseline, 12 and 24 months and correlated with clinical disability (Expanded Disability Status Scale, EDSS), and the Multiple Sclerosis Functional Composite Score (MSFC). MRI was performed at study entry and after two years. MAIN OUTCOME MEASURE: Correlation of ventricular diameters measured by TCS and MRI with assessment of clinical disability in MS patients at baseline and after two years. RESULTS: TCS and MRI measurements especially of third ventricle diameter matched closely at study entry and after two years (r = 0.9; p < 0.0001). At all time points the width of the third ventricle was significantly correlated with clinical disability (EDSS: r = 0.6, p < 0.01; MSFC: r = -0.6, p < 0.02). In the follow-up over 2 years there was an increase of the width of the third ventricle in comparison with study entry (p < 0.002). Increase of third ventricular width at study entry was associated with higher EDSS levels after 2 years (p = 0.01). CONCLUSION: Assessment of ventricular diameters by TCS is a reliable tool with which to monitor brain atrophy in the longitudinal follow-up of MS patients. Because TCS is a simple, inexpensive, non-invasive and generally available bedside-test it may be used in clinical practice as well as in therapeutic trials to assess brain atrophy.

Adolescent↗
PubMed2004

Improving MS patient care.

Multiple sclerosis (MS) is a multidimensional, chronic, neurological disease affecting young people that often interferes with their life and career plans. Patient care begins at the time of diagnosis, and particular emphasis should be placed on proper education about the variable disease course and treatment options. Clinical assessment at regular intervals using quantitative measures is recommended in order to obtain important information on the effects of disease-modifying and/or symptomatic treatment. In addition to optimising therapy, it is imperative to develop effective and properly resourced care services for MS patients that will address their complex and lifelong requirements.

Activities of Daily Living↗