Publications by authors named "Kai Kappert"

70 Publications

A Matter of Caution: Coagulation Parameters in COVID-19 Do Not Differ from Patients with Ruled-Out SARS-CoV-2 Infection in the Emergency Department.

TH Open 2021 Jan 6;5(1):e43-e55. Epub 2021 Feb 6.

Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.

COVID-19 (coronavirus disease 2019) patients often show excessive activation of coagulation, associated with increased risk of thrombosis. However, the diagnostic value of coagulation at initial clinical evaluation is not clear. We present an in-depth analysis of coagulation in patients presenting to the emergency department (ED) with suspected COVID-19.  = 58 patients with clinically suspected COVID-19 in the ED were enrolled.  = 17 subsequently tested positive using SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) polymerase chain reaction (PCR) swabs, while in  = 41 COVID-19 was ruled-out. We analyzed both standard and extended coagulation parameters, including thromboplastin time (INR), activated partial thromboplastin time (aPTT), antithrombin, plasminogen, plasminogen activator inhibitor-1 (PAI-1), D-dimers, and fibrinogen at admission, as well as α2-antiplasmin, activated protein C -resistance, factor V, lupus anticoagulant, protein C, protein S, and von Willebrand diagnostics. These data, as well as mortality and further laboratory parameters, were compared across groups based on COVID-19 diagnosis and severity of disease. In patients with COVID-19, we detected frequent clotting abnormalities, including D-dimers. The comparison cohort in the ED, however, showed similarly altered coagulation. Furthermore, parameters previously shown to distinguish between severe and moderate COVID-19 courses, such as platelets, plasminogen, fibrinogen, aPTT, INR, and antithrombin, as well as multiple nonroutine coagulation analytes showed no significant differences between patients with and without COVID-19 when presenting to the ED. At admission to the ED the prevalence of coagulopathy in patients with COVID-19 is high, yet comparable to the non-COVID-19 cohort presenting with respiratory symptoms. Nevertheless, coagulopathy might worsen during disease progression with the need of subsequent risk stratification.
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http://dx.doi.org/10.1055/s-0040-1722612DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7867413PMC
January 2021

Role of cell adhesion molecules for disease development of patients with and without COVID-19 in the emergency department.

J Infect Dis 2021 Jan 27. Epub 2021 Jan 27.

Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Berlin, Germany.

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http://dx.doi.org/10.1093/infdis/jiab042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7928779PMC
January 2021

Outcome prediction by serum calprotectin in patients with COVID-19 in the emergency department.

J Infect 2021 04 17;82(4):84-123. Epub 2020 Nov 17.

Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Berlin, Germany; Labor Berlin - Charité Vivantes GmbH, Berlin, Germany.

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http://dx.doi.org/10.1016/j.jinf.2020.11.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7670934PMC
April 2021

Severe COVID-19 Is Marked by a Dysregulated Myeloid Cell Compartment.

Cell 2020 09 5;182(6):1419-1440.e23. Epub 2020 Aug 5.

Department of Infectious Diseases and Respiratory Medicine, Charité, Universitätsmedizin Berlin, Berlin, Germany; German Center for Lung Research (DZL).

Coronavirus disease 2019 (COVID-19) is a mild to moderate respiratory tract infection, however, a subset of patients progress to severe disease and respiratory failure. The mechanism of protective immunity in mild forms and the pathogenesis of severe COVID-19 associated with increased neutrophil counts and dysregulated immune responses remain unclear. In a dual-center, two-cohort study, we combined single-cell RNA-sequencing and single-cell proteomics of whole-blood and peripheral-blood mononuclear cells to determine changes in immune cell composition and activation in mild versus severe COVID-19 (242 samples from 109 individuals) over time. HLA-DRCD11c inflammatory monocytes with an interferon-stimulated gene signature were elevated in mild COVID-19. Severe COVID-19 was marked by occurrence of neutrophil precursors, as evidence of emergency myelopoiesis, dysfunctional mature neutrophils, and HLA-DR monocytes. Our study provides detailed insights into the systemic immune response to SARS-CoV-2 infection and reveals profound alterations in the myeloid cell compartment associated with severe COVID-19.
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http://dx.doi.org/10.1016/j.cell.2020.08.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7405822PMC
September 2020

Assessment of serum ferritin as a biomarker in COVID-19: bystander or participant? Insights by comparison with other infectious and non-infectious diseases.

Biomarkers 2020 Dec 24;25(8):616-625. Epub 2020 Nov 24.

Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité - Universitätsmedizin Berlin, Berlin, Germany.

Background: The 2019 coronavirus disease (COVID-19) caused by the SARS-CoV-2 virus has an impact on all aspects of patient care. Serum ferritin generally represents a biomarker of choice when iron deficiency is suspected. However, ferritin is also an acute-phase-protein exhibiting elevated serum concentration in various inflammatory diseases. Here we focus on the role of serum ferritin for diagnostic and clinical management of patients with COVID-19 in comparison with other infectious and non-infectious diseases.

Methods: We examined scientific articles listed in PubMed reporting on ferritin in various infectious and non-infectious diseases. We then compared these results with nine current COVID-19 ferritin reports published in 2020.

Results: Several non-infectious, as well as non-COVID-19 infectious diseases, are characterised by a partly dramatic elevation of serum ferritin levels. All COVID-19 studies published between February and May 2020, which documented laboratory serum ferritin, indicate ferritin as a biomarker of COVID-19 severity in hospitalised patients.

Conclusions: Serum ferritin may be considered both a prognostic and stratifying biomarker that can also contribute to therapeutic decision-making concerning patients with COVID-19. It should be emphasised, however, that most scientific reports refer to cohorts in the Asian region. Further validation in other cohorts is urgently required.
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http://dx.doi.org/10.1080/1354750X.2020.1797880DOI Listing
December 2020

GPx3 dysregulation impacts adipose tissue insulin receptor expression and sensitivity.

JCI Insight 2020 06 4;5(11). Epub 2020 Jun 4.

Junior Research Group Central Regulation of Metabolism, German Institute of Human Nutrition, Nuthetal, Germany.

Insulin receptor signaling is crucial for white adipose tissue (WAT) function. Consequently, lack of insulin receptor (IR) in WAT results in a diabetes-like phenotype. Yet, causes for IR downregulation in WAT of patients with diabetes are not well understood. By using multiple mouse models of obesity and insulin resistance, we identify a common downregulation of IR with a reduction of mRNA expression of selenoproteins Txnrd3, Sephs2, and Gpx3 in gonadal adipose tissue. Consistently, GPX3 is also decreased in adipose tissue of insulin-resistant and obese patients. Inducing Gpx3 expression via selenite treatment enhances IR expression via activation of the transcription factor Sp1 in 3T3-L1 preadipocytes and improves adipocyte differentiation and function. Feeding mice a selenium-enriched high-fat diet alleviates diet-induced insulin resistance with increased insulin sensitivity, decreased tissue inflammation, and elevated IR expression in WAT. Again, IR expression correlated positively with Gpx3 expression, a phenotype that is also conserved in humans. Consequently, decreasing GPx3 using siRNA technique reduced IR expression and insulin sensitivity in 3T3-L1 preadipocytes. Overall, our data identify GPx3 as a potentially novel regulator of IR expression and insulin sensitivity in adipose tissue.
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http://dx.doi.org/10.1172/jci.insight.136283DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7308064PMC
June 2020

Sex-specific metabolic and functional differences in human umbilical vein endothelial cells from twin pairs.

Atherosclerosis 2019 12 10;291:99-106. Epub 2019 Oct 10.

Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Medizinische Klinik für Kardiologie und Angiologie, Campus Mitte, Berlin, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Germany. Electronic address:

Background And Aims: Gonadal hormones are mainly thought to account for sex and gender differences in the incidence, clinical manifestation and therapy of many cardiovascular diseases. However, intrinsic sex differences at the cellular level are mostly overlooked. Here, we assessed sex-specific metabolic and functional differences between male and female human umbilical vein endothelial cells (HUVECs).

Methods: Cellular metabolism was investigated by bioenergetic studies (Seahorse Analyser) and a metabolomic approach. Protein levels were determined by Western blots and proteome analysis. Vascular endothelial growth factor (VEGF)-stimulated cellular migration was assessed by gap closure. HUVECs from dizygotic twin pairs were used for most experiments.

Results: No sex differences were observed in untreated cells. However, sexual dimorphisms appeared after stressing the cells by serum starvation and treatment with VEGF. Under both conditions, female cells had higher intracellular ATP and metabolite levels. A significant decline in ATP levels was observed in male cells after serum starvation. After VEGF, the ratio of glycolysis/mitochondrial respiration was higher in female cells and migration was more pronounced.

Conclusions: These results point to an increased stress tolerance of female cells. We therefore propose that female cells have an energetic advantage over male cells under conditions of diminished nutrient supply. A more favourable energy balance of female HUVECs after serum starvation and VEGF could potentially explain their stronger migratory capacity.
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http://dx.doi.org/10.1016/j.atherosclerosis.2019.10.007DOI Listing
December 2019

Platelet-derived growth factor receptor β activation and regulation in murine myelofibrosis.

Haematologica 2020 08 31;105(8):2083-2094. Epub 2019 Oct 31.

Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Berlin, Germany

There is prevailing evidence to suggest a decisive role for platelet-derived growth factors (PDGF) and their receptors in primary myelofibrosis. While PDGF receptor β (PDGFRβ) expression is increased in bone marrow stromal cells of patients correlating with the grade of myelofibrosis, knowledge on the precise role of PDGFRβ signaling in myelofibrosis is sparse. Using the Gata-1 mouse model for myelofibrosis, we applied RNA sequencing, protein expression analyses, multispectral imaging and, as a novel approach in bone marrow tissue, an proximity ligation assay to provide a detailed characterization of PDGFRβ signaling and regulation during development of myelofibrosis. We observed an increase in PDGFRβ and PDGF-B protein expression in overt fibrotic bone marrow, along with an increase in PDGFRβ-PDGF-B interaction, analyzed by proximity ligation assay. However, PDGFRβ tyrosine phosphorylation levels were not increased. We therefore focused on regulation of PDGFRβ by protein tyrosine phosphatases as endogenous PDGFRβ antagonists. Gene expression analyses showed distinct expression dynamics among PDGFRβ-targeting phosphatases. In particular, we observed enhanced T-cell protein tyrosine phosphatase protein expression and PDGFRβ-T-cell protein tyrosine phosphatase interaction in early and overt fibrotic bone marrow of Gata-1 mice. , T-cell protein tyrosine phosphatase () knockdown increased PDGFRβ phosphorylation at Y and Y, leading to enhanced downstream signaling in fibroblasts. Furthermore, knockdown cells showed increased growth rates when exposed to low-serum growth medium. Taken together, PDGF signaling is differentially regulated during myelofibrosis. Protein tyrosine phosphatases, which have so far not been examined during disease progression, are novel and hitherto unrecognized components in myelofibrosis.
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http://dx.doi.org/10.3324/haematol.2019.226332DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7395273PMC
August 2020

Underfilling of vacuum blood collection tubes leads to increased lactate dehydrogenase activity in serum and heparin plasma samples.

Clin Chem Lab Med 2020 01;58(2):213-221

Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Berlin, Germany.

Background Lactate dehydrogenase (LD) activity is routinely monitored for therapeutic risk stratification of malignant diseases, but is also prone to preanalytical influences. Methods We systematically analyzed the impact of defined preanalytical conditions on the hemolysis-susceptible parameters LD, potassium (K) and hemolysis index in vacuum blood collection tubes (serum [SE], heparin plasma [HP]). Blood was collected by venipuncture from healthy volunteers. Tubes were either filled or underfilled to approximately 50%, then processed directly or stored at room temperature for 4 h. Potassium (K), sodium (Na), chloride (Cl), LD, creatine kinase (CK), total cholesterol, and indices for hemolysis, icterus, and lipemia were analyzed. Filling velocity was determined in a subset of tubes. Findings in healthy volunteers were reconfirmed in an in-patient cohort (n = 74,751) that was analyzed for plasma yield and LD data distribution. Results LD activity was higher in HP compared to SE. Underfilling led to higher LD values (SE: +21.6%; HP: +28.3%), K (SE: +4.2%; HP: +5.3%), and hemolysis index (SE: +260.8%; HP: +210.0%), while other analytes remained largely unchanged. Filling velocity of tubes was approximately 3-fold higher in the first half compared to the second half in both HP and SE collection tubes. Importantly, plasma yield also inversely correlated with LD in routine patients. By calculating reference limits, the lowest plasma yield quartile of the patient cohort displayed LD values clearly exceeding current reference recommendations. Conclusions Underfilling of tubes leads to a higher proportion of blood aspirated with high velocity and relevant elevations in LD. This finding should be considered in cases of clinically implausible elevated LD activities.
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http://dx.doi.org/10.1515/cclm-2019-0616DOI Listing
January 2020

High frequency of drug resistance mutations in the HBV genome in ART-experienced HIV-coinfected patients in southwestern Nigeria.

Antivir Ther 2019 ;24(7):521-528

Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany.

Background: HBV and HIV infections are highly endemic in sub-Saharan Africa and Nigeria while HBV-HIV coinfection is not uncommon. Antiretroviral (ART)-treatment for HIV can affect HBV whereby antiviral resistance mutations in the HBV genome can be selected. Here, we determined the prevalence of resistance mutations among ART-experienced and ART-naive HIV-HBV-coinfected patients in southwestern Nigeria.

Methods: A total of 81 serum samples from HBV-HIV-coinfected patients who were either ART-naive or received lamivudine (3TC)-containing ART-therapy and HBV-monoinfected patients were analysed. Hepatitis B surface antigen (HBsAg) was detected using ELISA. HBV-positive samples were confirmed by PCR amplification of the surface and polymerase regions. Mutations conferring drug resistance to HBV were analysed by direct sequencing. Phylogenetic analysis was performed to identify the HBV genotype.

Results: Of the 81 HBsAg-positive samples, 27 had detectable HBV DNA by real-time PCR with mean viral loads of 6.77 log IU/ml. Phylogenetic analyses showed a predominance of HBV genotype E. A high prevalence (22.2%; 6/27) of HBV resistance mutations among ART-experienced HBV-HIV-coinfected patients was detected. However, a relatively high selection rate of resistance mutations in drug-naive HIV-HBV-coinfected (3.7%; 1/27) and in HBV-monoinfected patients, potential drug resistance mutations (7.4%; 2/27) were also observed. HBV polymerase amino acid substitutions found included rtV173L, rtL180M, rtM204V, rtK212R, rtS213T, rtV214A, rtL229V and rtP237A/S.

Conclusions: Drug resistant mutations were detected frequently in ART-experienced HIV-HBV patients. Well-coordinated antiviral therapy for HIV patients coinfected with HBV should include proper HBV diagnosis and resistance testing to minimize the emergence and spread of antiviral drug resistance.
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http://dx.doi.org/10.3851/IMP3333DOI Listing
October 2020

Multiplex plasma protein profiling identifies novel markers to discriminate patients with adenocarcinoma of the lung.

BMC Cancer 2019 Jul 29;19(1):741. Epub 2019 Jul 29.

Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.

Background: The overall prognosis of non-small cell lung cancer (NSCLC) is poor, and currently only patients with localized disease are potentially curable. Therefore, preferably non-invasively determined biomarkers that detect NSCLC patients at early stages of the disease are of high clinical relevance. The aim of this study was to identify and validate novel protein markers in plasma using the highly sensitive DNA-assisted multiplex proximity extension assay (PEA) to discriminate NSCLC from other lung diseases.

Methods: Plasma samples were collected from a total of 343 patients who underwent surgical resection for different lung diseases, including 144 patients with lung adenocarcinoma (LAC), 68 patients with non-malignant lung disease, 83 patients with lung metastasis of colorectal cancers and 48 patients with typical carcinoid. One microliter of plasma was analyzed using PEA, allowing detection and quantification of 92 established cancer related proteins. The concentrations of the plasma proteins were compared between disease groups.

Results: The comparison between LAC and benign samples revealed significantly different plasma levels for four proteins; CXCL17, CEACAM5, VEGFR2 and ERBB3 (adjusted p-value < 0.05). A multi-parameter classifier was developed to discriminate between samples from LAC patients and from patients with non-malignant lung conditions. With a bootstrap aggregated decision tree algorithm (TreeBagger), a sensitivity of 93% and specificity of 64% was achieved to detect LAC in this risk population.

Conclusions: By applying the highly sensitive PEA, reliable protein profiles could be determined in microliter amounts of plasma. We further identified proteins that demonstrated different plasma concentration in defined disease groups and developed a signature that holds potential to be included in a screening assay for early lung cancer detection.
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http://dx.doi.org/10.1186/s12885-019-5943-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6664554PMC
July 2019

Pulmonary arterial remodelling by deficiency of peroxisome proliferator-activated receptor-γ in murine vascular smooth muscle cells occurs independently of obesity-related pulmonary hypertension.

Respir Res 2019 Feb 27;20(1):42. Epub 2019 Feb 27.

Berlin Institute of Health, Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Center for Cardiovascular Research (CCR), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany.

Background: Obesity is associated with cardiovascular complications, including pulmonary hypertension (PH). Reports suggest that peroxisome proliferator-activated receptor-γ (PPARγ) has direct action in preventing vascular remodelling in PH. Here we dissected the specific role of high-fat-diet (HFD)-induced obesity and vascular smooth muscle cell (VSMC)-PPARγ for remodelling of small pulmonary arteries.

Methods: Wild-type (WT) and VSMC-specific PPARγ-knockout (SmPparγ) mice were fed a low-fat-diet (LFD, 10% kcal from fat) or HFD (60% kcal from fat) for 24 weeks. Mice were metabolically phenotyped (e.g. weight development, insulin/glucose tolerance) at the beginning, and after 12 and 24 weeks, respectively. At 24 weeks additionally pulmonary pressure, heart structure, pulmonary vascular muscularization together with gene and protein expression in heart and lung tissues were determined.

Results: HFD increased right ventricular systolic pressure (RVSP) to a similar extent in WT and SmPparγ mice. HFD decreased glucose tolerance and insulin sensitivity in both WT and SmPparγ mice. Importantly, the increase in RVSP correlated with the degree of insulin resistance. However, VSMC-PPARγ deficiency increased pulmonary vascular muscularization independently of the diet-induced rise in RVSP. This increase was associated with elevated expression of early growth response protein 1 in heart and osteopontin in lung tissue.

Conclusions: Here we demonstrate a correlation of insulin resistance and pulmonary pressure. Further, deficiency of PPARγ in VSMCs diet-independently leads to increased pulmonary vascular muscularization.
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http://dx.doi.org/10.1186/s12931-019-1003-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6391752PMC
February 2019

The effect of blood sampling and preanalytical processing on human N-glycome.

PLoS One 2018 11;13(7):e0200507. Epub 2018 Jul 11.

Charité -Universitätsmedizin Berlin, Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Berlin, Germany.

Glycome modulations have been described in the onset and progression of many diseases. Thus, many studies have proposed glycans from blood glycoproteins as disease markers. Astonishingly, little effort has been given unraveling preanalytical conditions potentially influencing glycan analysis prior to blood biomarker studies. In this work, we evaluate for the first time the effect of hemolysis, storage and blood collection, but also influence of various times and temperatures between individual processing steps on the total N-glycome and on a glycan-biomarker score. Venous blood was collected from 10 healthy donors in 11 blood collection tubes with different additives, processed variously to obtain 16 preanalytical variables and N-glycans released from serum or plasma were analyzed by MALDI-TOF-MS and capillary electrophoresis coupled with fluorescence detection (CE-LIF) for the first time. Long time storage of deep frozen samples at -20°C or -80°C exerted only a minor influence on the glycome as demonstrated by CE-LIF. The N-glycome was very stable evidenced by MALDI-TOF when stored at 4°C for at least 48 hours and blood collected in tubes devoid of additives. The glycome was stable upon storage after centrifugation and aliquoting, which is an important information considering future diagnostic applications. Hemolysis, however, negatively correlated with an established glycan score for ovarian cancer, when evaluated by MALDI-TOF-MS measurement by affecting relative intensities of certain glycans, which could lead to false negative / positive results in glycan biomarker studies.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0200507PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6040761PMC
January 2019

The cytoskeleton in 'couch potato-ism': Insights from a murine model of impaired actin dynamics.

Exp Neurol 2018 08 21;306:34-44. Epub 2018 Apr 21.

Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Klinik für Psychiatrie und Psychotherapie, 10117 Berlin, Germany; Klinik und Poliklinik für Psychiatrie und Psychotherapie, Universitätsmedizin Rostock, 18147 Rostock, Germany.

Evidence for a critical pathophysiological role of aberrant cytoskeletal dynamics is being uncovered in a growing number of neuropsychiatric syndromes. A sedentary lifestyle as well as overt psychopathology is prevalent in patients with the metabolic syndrome. Using mice deficient in gelsolin (Gsn), a crucial actin-severing protein, we here investigated reduced actin turnover as a potential common driver of metabolic disturbances, sedentary behavior, and an anxious/depressive phenotype. Gelsolin deficiency resulted in reduced lifespan. As compared to wildtype controls, Gsn mice (~ 9 weeks) fed a high-fat diet (HFD) over a span of 12 weeks showed increased body weight gain, fat mass, hepatic steatosis, and adipocyte hypertrophy as well as a significantly reduced respiratory quotient. Moreover, increased rigidity of the actin cytoskeleton in mice on HFD induced mRNA expression of Acc1, Acc2, Fasn, and Lipe, key genes involved in fatty acid metabolism in the liver. Glucose tolerance and insulin sensitivity were worsened in Gsn HFD relative to Gsn HFD mice. Hypertension in Gsn mice was associated with reduced endothelial NO synthase (eNOS) mRNA expression and reduced eNOS protein trafficking to the plasma membrane. Furthermore, acetylcholine-induced cGMP production and relaxation of aortic rings were impaired by actin filament stabilization. Gsn mice on HFD displayed reduced corticosterone concentrations and reduced energy expenditure as compared to Gsn HFD mice. Moreover, Gsn HFD mice displayed an overall pattern of hypoactive and anxious/depressive-like behavior. In aggregate, our results demonstrate that impaired actin filament dynamics promote the development of key behavioral and physiological aspects of the metabolic syndrome.
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http://dx.doi.org/10.1016/j.expneurol.2018.04.004DOI Listing
August 2018

AT1-receptor blockade attenuates outward aortic remodeling associated with diet-induced obesity in mice.

Clin Sci (Lond) 2017 08 13;131(15):1989-2005. Epub 2017 Jul 13.

Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin; and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research (CCR), Germany

The renin-angiotensin system (RAS) and obesity have been implicated in vascular outward remodeling, including aneurysms, but the precise mechanisms are not yet understood. We investigated the effect of the angiotensin receptor type 1 (AT1-receptor) antagonist telmisartan on aortic outward remodeling in a diet-induced obesity model in mice. C57/Black6J mice were fed either a low-fat diet (LFD) or a high-fat diet (HFD) for 14 weeks. One group of HFD mice was additionally exposed to telmisartan (3 mg/kg per day) for the last 4 weeks. HFD led to aortic outward remodeling, characterized by increased proteolysis, along with structural changes, such as fragmentation of elastic fibers and decreased elastin content. Vascular damage was associated with up-regulation of matrix metalloproteinase (MMP)-2 (MMP-2), MMP-3, MMP-12, cathepsin D, and cathepsin B. HFD aortae exhibited an enhanced inflammatory status, characterized by tumor necrosis factor α (TNF-α) and interleukin-1β (IL-1β) colocalized with adipocytes in the adventitia. HFD resulted in a significant increase in aortic dimensions, evident by ultrasound measurements. Telmisartan abolished aortic dilatation and preserved elastin content. HFD induced enhanced expression of aortic MMP-2, MMP-9, and TNF-α was abrogated by telmisartan. Adventitial proteolytic and inflammatory factors were also examined in samples from human abdominal aneurysms. The expression of TNF-α, IL-1β, and MMP-9 was higher in the adventitial fat of diseased vessels compared with healthy tissues. Finally, adipocytes treated with TNF-α showed enhanced MMP-2, MMP-3, and cathepsin D, which was prevented by telmisartan. Taken together, HFD in mice induced aortic dilatation with up-regulation of matrix degrading and inflammatory pathways similar to those seen in human aortic aneurysmatic tissue. The HFD-induced vascular pathology was reduced by AT1-receptor antagonist telmisartan.
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http://dx.doi.org/10.1042/CS20170131DOI Listing
August 2017

High incidence of cardiac dysfunction and response to antiviral treatment in patients with chronic hepatitis C virus infection.

Clin Res Cardiol 2017 Jul 24;106(7):551-556. Epub 2017 Feb 24.

Department of Cardiology, Campus Benjamin Franklin, CC11, Charité-Universitätsmedizin Berlin, Hindenburgdamm 30, 12200, Berlin, Germany.

Aims: Hepatitis C virus (HCV) has been associated with cardiomyopathies. Former anti-HCV therapies employing interferon could have serious side effects in patients with advanced heart failure since interferon may adversely impact upon cardiac function. We, therefore, examined whether the novel, interferon-free and highly virus-selective anti-HCV combination therapy might be applicable even in advanced or end-stage heart failure.

Methods And Results: In a retrospective series of HCV-positive patients admitted to our institution with suspected cardiac disease, coronary, valvular or hypertensive heart disease was diagnosed in 70/146 (47.9%). Among the others, 36/76 (47.4%) had myocardial disease: LV (32.9%)/RV (13.2%) hypertrophy, RV dysfunction (13.2%)/dilation (6.6%), severe diastolic dysfunction (7.9%), pulmonary hypertension (22.4%). One critically ill patient listed for heart transplantation (HTX) had previously not tolerated an interferon-based protocol. To still improve her chance of enduring transplant survival, we attempted an interferon-free virus-selective antiviral combination drug protocol under careful monitoring of possible side effects. Regarding clinical status she tolerated this treatment well, with the exception of transient severe hyponatremia requiring substitution. Her NYHA functional class improved from II-IV before to class II immediately after successful complete HCV elimination.

Conclusions: Whereas prevalence of cardiac dysfunction and potential benefit from antiviral treatment was reported previously, there is lack of data regarding the response of patients with advanced heart failure. Since the highly HCV-selective drugs used above do not eliminate other cardiotropic viruses and have no direct effect on inflammation, massive improvement in such critically ill patients indicates a causal role of HCV in their cardiac failure, and of HCV elimination in their functional recovery.
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http://dx.doi.org/10.1007/s00392-017-1086-1DOI Listing
July 2017

PCSK9 regulates the chemokine receptor CCR2 on monocytes.

Biochem Biophys Res Commun 2017 04 20;485(2):312-318. Epub 2017 Feb 20.

Department of Medicine/Cardiology, Deutsches Herzzentrum Berlin, Germany. Electronic address:

Monocyte migration is a key element in atherosclerosis. LDL-C facilitates monocyte migration via induction of CCR2. PCSK9 regulates cell surface expression of the LDL-R and is expressed in vascular smooth muscle cells (VSMCs). The present study was done to investigate the regulation of PCSK9 in VSMCs and its impact on monocyte function.

Methods And Results: PCSK9 mRNA and protein levels were upregulated in VSMCs by the TLR-4 ligand LPS, whereas TGF-β or angiotensin II had no effect. Induction of PCSK9 was selectively inhibited by TLR-4 blockade and further downstream by the SAPK/JNK-inhibitor SP600125, whereas inhibitors of ERK1/2, p38 or PI3-kinase pathways had no effect. Incubation of monocytes in conditioned media from LPS-stimulated VSMCs resulted in a significant reduction of LDL-R levels on monocytes, comparable to the effects of recombinant PCSK9. LDL-C increased monocyte CCR2 expression, which augmented monocyte migration towards MCP-1. This LDL-C dependent monocyte chemotaxis was inhibited by supernatants from LPS-stimulated VSMCs, similar to recombinant PCSK9 and a specific LDL-R blocking antibody.

Conclusion: PCSK9 is regulated in VSMCs by TLR-4 - SAPK/JNK signaling, a pathway important in inflammation and metabolism. VSMC-derived PCSK9 reduces monocyte LDL-R expression, affecting LDL-C/LDL-R-mediated CCR2-expression on monocytes, which is crucial to cell motility and atherogenesis.
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http://dx.doi.org/10.1016/j.bbrc.2017.02.085DOI Listing
April 2017

Transcriptome analysis of periodontitis-associated fibroblasts by CAGE sequencing identified DLX5 and RUNX2 long variant as novel regulators involved in periodontitis.

Sci Rep 2016 09 20;6:33666. Epub 2016 Sep 20.

Department of Biochemistry, Ohu University School of Pharmaceutical Sciences, Misumido 31-1, Tomitamachi, Koriyama, Fukushima 963-8611, Japan.

Periodontitis is affecting over half of the adult population, and represents a major public health problem. Previously, we isolated a subset of gingival fibroblasts (GFs) from periodontitis patients, designated as periodontitis-associated fibroblasts (PAFs), which were highly capable of collagen degradation. To elucidate their molecular profiles, GFs isolated form healthy and periodontitis-affected gingival tissues were analyzed by CAGE-seq and integrated with the FANTOM5 atlas. GFs from healthy gingival tissues displayed distinctive patterns of CAGE profiles as compared to fibroblasts from other organ sites and characterized by specific expression of developmentally important transcription factors such as BARX1, PAX9, LHX8, and DLX5. In addition, a novel long non-coding RNA associated with LHX8 was described. Furthermore, we identified DLX5 regulating expression of the long variant of RUNX2 transcript, which was specifically active in GFs but not in their periodontitis-affected counterparts. Knockdown of these factors in GFs resulted in altered expression of extracellular matrix (ECM) components. These results indicate activation of DLX5 and RUNX2 via its distal promoter represents a unique feature of GFs, and is important for ECM regulation. Down-regulation of these transcription factors in PAFs could be associated with their property to degrade collagen, which may impact on the process of periodontitis.
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http://dx.doi.org/10.1038/srep33666DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5028883PMC
September 2016

Activation of Peroxisome Proliferator-Activated Receptor-δ as Novel Therapeutic Strategy to Prevent In-Stent Restenosis and Stent Thrombosis.

Arterioscler Thromb Vasc Biol 2016 08 9;36(8):1534-48. Epub 2016 Jun 9.

From the Department of Molecular Medicine, A.I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland (J.H., S.Y.-H.); Centre for R&D, Uppsala University/County Council of Gaevleborg, Gaevle, Sweden (O.L.); Institute for Pathology, University Clinic of Schleswig-Holstein, Campus Kiel, Kiel, Germany (J.H.B.); Max-Delbrück Center for Molecular Medicine, Berlin, Germany (W.-H.S., D.M., A.H., J.-D.D., L.T., F.B.); Department of Cardiology (B.P., F.B.) and Center for Cardiovascular Research/CCR, Institute of Laboratory Medicine Clinical Chemistry and Pathobiochemistry (K.K.), Charité-Universitaetsmedizin Berlin, Berlin, Germany; Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Teltow, Germany (F.J., C.M.); Institute for Diabetes and Obesity, Helmholtz Zentrum Muenchen, Munich, German Research Center for Environmental Health, Germany (M.J.); and Cologne Interventional Immunology, University Hospital of Cologne, Cologne, Germany (M.v.B.-B.).

Objective: Drug-eluting coronary stents reduce restenosis rate and late lumen loss compared with bare-metal stents; however, drug-eluting coronary stents may delay vascular healing and increase late stent thrombosis. The peroxisome proliferator-activated receptor-delta (PPARδ) exhibits actions that could favorably influence outcomes after drug-eluting coronary stents placement.

Approach And Results: Here, we report that PPARδ ligand-coated stents strongly reduce the development of neointima and luminal narrowing in a rabbit model of experimental atherosclerosis. Inhibition of inflammatory gene expression and vascular smooth muscle cell (VSMC) proliferation and migration, prevention of thrombocyte activation and aggregation, and proproliferative effects on endothelial cells were identified as key mechanisms for the prevention of restenosis. Using normal and PPARδ-depleted VSMCs, we show that the observed effects of PPARδ ligand GW0742 on VSMCs and thrombocytes are PPARδ receptor dependent. PPARδ ligand treatment induces expression of pyruvate dehydrogenase kinase isozyme 4 and downregulates the glucose transporter 1 in VSMCs, thus impairing the ability of VSMCs to provide the increased energy demands required for growth factor-stimulated proliferation and migration.

Conclusions: In contrast to commonly used drugs for stent coating, PPARδ ligands not only inhibit inflammatory response and proliferation of VSMCs but also prevent thrombocyte activation and support vessel re-endothelialization. Thus, pharmacological PPARδ activation could be a promising novel strategy to improve drug-eluting coronary stents outcomes.
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http://dx.doi.org/10.1161/ATVBAHA.115.306962DOI Listing
August 2016

Inhibition of Src homology 2 domain-containing phosphatase 1 increases insulin sensitivity in high-fat diet-induced insulin-resistant mice.

FEBS Open Bio 2016 Mar 4;6(3):179-89. Epub 2016 Jan 4.

Center for Cardiovascular Research/CCR Institute of Laboratory Medicine Clinical Chemistry and Pathobiochemistry Charité - Universitätsmedizin Germany.

Insulin resistance plays a crucial role in the development of type 2 diabetes. Insulin receptor signalling is antagonized and tightly controlled by protein tyrosine phosphatases (PTPs). However, the precise role of the PTP src homology 2 domain-containing phosphatase 1 (SHP-1) in insulin resistance has not been explored. Male C57BL/6J mice were fed a high-fat diet (HFD, 60% kcal from fat), to induce insulin resistance, or a low-fat diet (LFD, 10% kcal from fat) for 10 weeks. Afterwards, HFD-fed mice were pharmacologically treated with the SHP-1 (Ptpn6) inhibitor sodium stibogluconate and the broad spectrum pan-PTP inhibitor bis(maltolato)oxovanadium(IV) (BMOV). Both inhibitors ameliorated the metabolic phenotype, as evidenced by reduced body weight, improved insulin sensitivity and glucose tolerance, which was not due to altered PTP gene expression. In parallel, phosphorylation of the insulin receptor and of the insulin signalling key intermediate Akt was enhanced, and both PTP inhibitors and siRNA-mediated SHP-1 downregulation resulted in an increased glucose uptake in vitro. Finally, recombinant SHP-1 was capable of dephosphorylating the ligand-induced tyrosine-phosphorylated insulin receptor. These results indicate a central role of SHP-1 in insulin signalling during obesity, and SHP-1 inhibition as a potential therapeutic approach in metabolic diseases.
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http://dx.doi.org/10.1002/2211-5463.12000DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4794785PMC
March 2016

Fibroblast VEGF-receptor 1 expression as molecular target in periodontitis.

J Clin Periodontol 2016 Feb 23;43(2):128-37. Epub 2016 Feb 23.

Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Center for Cardiovascular Research (CCR), Charité-University Medicine Berlin, Berlin, Germany.

Aim: Degradation of extracellular matrices is an integral part in periodontitis. For antagonizing this pathophysiological mechanism, we aimed at identifying gene expression profiles in disease progression contributing periodontitis-associated fibroblasts (PAFs) versus normal gingival fibroblasts to determine their molecular repertoire, and exploit it for therapeutic intervention.

Materials And Methods: Applying an exploratory analysis using a small number of microarrays in combination with a three dimensional (3D) in vitro culture model that incorporates some aspects of periodontitis, PAFs were initially characterized by gene-expression analyses, followed by targeted gene down-regulation and pharmacological intervention in vitro. Further, immunohistochemistry was applied for phosphorylation analyses in tissue specimens.

Results: PAFs were characterized by 42 genes being commonly up-regulated >1.5-fold, and by five genes that were concordantly down-regulated (<0.7-fold). Expression of vascular endothelial growth factor (VEGF)-receptor 1 (Flt-1) was highly enhanced, and was thus further explored in in vitro culture models of periodontal fibroblasts without accounting for the microbiome. Phosphorylation of the VEGF-receptor 1 was enhanced in PAFs. Receptor inhibition by a specific VEGF-receptor inhibitor or intrinsic down-regulation by RNAi of the VEGF-receptor kinase in 3D gel cultures resulted in significant reduction in collagen degradation associated with increased tissue inhibitor of metalloproteinase expression, suggesting that Flt-1 may contribute to periodontitis.

Conclusion: Based on the finding that VEGF-receptor kinase inhibition impaired collagen degradation pathways, Flt-1 may represent a candidate for therapeutic approaches in periodontitis.
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http://dx.doi.org/10.1111/jcpe.12495DOI Listing
February 2016

Pioglitazone alleviates cardiac and vascular remodelling and improves survival in monocrotaline induced pulmonary arterial hypertension.

Naunyn Schmiedebergs Arch Pharmacol 2016 Apr 7;389(4):369-79. Epub 2016 Jan 7.

Department of Internal Medicine III; Heart Center, University of Cologne, Cologne, Germany.

Pulmonary arterial hypertension (PAH) is a fatal disease with limited therapeutic options. Pathophysiological changes comprise obliterative vascular remodelling of small pulmonary arteries, elevated mean pulmonary arterial systolic pressure (PASP) due to elevated resistance of pulmonary vasculature, adverse right ventricular remodelling, and heart failure. Recent findings also indicate a role of increased inflammation and insulin resistance underlying the development of PAH. We hypothesized that treatment of this condition with the peroxisome proliferator-activated receptor-γ (PPARγ) activator pioglitazone, known to regulate the expression of different genes addressing insulin resistance, inflammatory changes, and vascular remodelling, could be a beneficial approach. PAH was induced in adult rats by a single subcutaneous injection of monocrotaline (MCT). Pioglitazone was administered for 2 weeks starting 3 weeks after MCT-injection. At day 35, hemodynamics, organ weights, and -indices were measured. We performed morphological and molecular characterization of the pulmonary vasculature, including analysis of the degree of muscularization, proliferation rates, and medial wall thickness of the small pulmonary arteries. Furthermore, markers of cardiac injury, collagen content, and cardiomyocyte size were analyzed. Survival rates were monitored throughout the experimental period. Pioglitazone treatment improved survival, reduced PASP, muscularization of small pulmonary arteries, and medial wall thickness. Further, MCT-induced right ventricular hypertrophy and fibrosis were attenuated. This was accompanied with reduced cardiac expression of brain natriuretic peptide, as well as decreased cardiomyocyte size. Finally, pulmonary macrophage content and osteopontin gene expression were attenuated. Based on the beneficial impact of pioglitazone, activation of PPARγ might be a promising treatment option in PAH.
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http://dx.doi.org/10.1007/s00210-015-1205-3DOI Listing
April 2016

Enhanced insulin signaling in density-enhanced phosphatase-1 (DEP-1) knockout mice.

Mol Metab 2015 Apr 12;4(4):325-36. Epub 2015 Feb 12.

Center for Cardiovascular Research/CCR, Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Hessische Str. 3-4, 10115 Berlin, Charité - Universitätsmedizin Berlin, Germany.

Objective: Insulin resistance can be triggered by enhanced dephosphorylation of the insulin receptor or downstream components in the insulin signaling cascade through protein tyrosine phosphatases (PTPs). Downregulating density-enhanced phosphatase-1 (DEP-1) resulted in an improved metabolic status in previous analyses. This phenotype was primarily caused by hepatic DEP-1 reduction.

Methods: Here we further elucidated the role of DEP-1 in glucose homeostasis by employing a conventional knockout model to explore the specific contribution of DEP-1 in metabolic tissues. Ptprj (-/-) (DEP-1 deficient) and wild-type C57BL/6 mice were fed a low-fat or high-fat diet. Metabolic phenotyping was combined with analyses of phosphorylation patterns of insulin signaling components. Additionally, experiments with skeletal muscle cells and muscle tissue were performed to assess the role of DEP-1 for glucose uptake.

Results: High-fat diet fed-Ptprj (-/-) mice displayed enhanced insulin sensitivity and improved glucose tolerance. Furthermore, leptin levels and blood pressure were reduced in Ptprj (-/-) mice. DEP-1 deficiency resulted in increased phosphorylation of components of the insulin signaling cascade in liver, skeletal muscle and adipose tissue after insulin challenge. The beneficial effect on glucose homeostasis in vivo was corroborated by increased glucose uptake in skeletal muscle cells in which DEP-1 was downregulated, and in skeletal muscle of Ptprj (-/-) mice.

Conclusion: Together, these data establish DEP-1 as novel negative regulator of insulin signaling.
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http://dx.doi.org/10.1016/j.molmet.2015.02.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4354926PMC
April 2015

CT-proET1 predicts pulmonary hemodynamics in Scleroderma-associated pulmonary hypertension.

Clin Res Cardiol 2015 Jun 24;104(6):525-9. Epub 2015 Feb 24.

Klinik III für Innere Medizin, Herzzentrum der Universität zu Köln, Kerpener Str. 62, 50937, Cologne, Germany.

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http://dx.doi.org/10.1007/s00392-015-0825-4DOI Listing
June 2015

Inhibition of protein tyrosine phosphatases enhances cerebral collateral growth in rats.

J Mol Med (Berl) 2014 Sep 27;92(9):983-94. Epub 2014 May 27.

Center for Cardiovascular Research (CCR), Department of Internal Medicine/Cardiology, Richard-Thoma-Laboratories for Arteriogenesis, Charité-University Medicine Berlin, Hessische Str. 3-4, 10115, Berlin, Germany.

Unlabelled: Arteriogenesis involves the rapid proliferation of preexisting arterioles to fully functional arteries as a compensatory mechanism to overcome circulatory deficits. Stimulation of arteriogenesis has therefore been considered a treatment concept in arterial occlusive disease. Here, we investigated the impact of inhibition of protein tyrosine phosphatases (PTPs) on cerebral arteriogenesis in rats. Arteriogenesis was induced by occlusion of one carotid and both vertebral arteries (three-vessel occlusion (3-VO)). Collateral growth and functional vessel perfusion was assessed 3-35 days following 3-VO. Furthermore, animals underwent 3-VO surgery and were treated with the pan-PTP inhibitor BMOV, the SHP-1 inhibitor sodium stibogluconate (SSG), or the PTP1B inhibitor AS279. Cerebral vessel diameters and cerebrovascular reserve capacity (CVRC) were determined, together with immunohistochemistry analyses and proximity ligation assays (PLA) for determination of tissue proliferation and phosphorylation patterns after 7 days. The most significant changes in vessel diameter increase were present in the ipsilateral posterior cerebral artery (PCA), with proliferative markers (PCNA) being time-dependently increased. The CVRC was lost in the early phase after 3-VO and partially recovered after 21 days. PTP inhibition resulted in a significant increase in the ipsilateral PCA diameter in BMOV-treated animals and rats subjected to PTP1B inhibition. Furthermore, CVRC was significantly elevated in AS279-treated rats compared to control animals, along with hyperphosphorylation of the platelet-derived growth factor-β receptor in the vascular wall in vivo. In summary, our data indicate PTPs as hitherto unrecognized negative regulators in cerebral arteriogenesis. Further, PTP inhibition leading to enhanced collateral growth and blood perfusion suggests PTPs as novel targets in anti-ischemic treatment.

Key Messages: PTPs exhibit negative regulatory function in cerebral collateral growth in rats. Inhibition of pan-PTP/PTP1B increases vessel PDGF-β receptor phosphorylation. PTP1B inhibition enhances arteriogenesis and cerebrovascular reserve capacity.
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http://dx.doi.org/10.1007/s00109-014-1164-zDOI Listing
September 2014

Knockout of Density-Enhanced Phosphatase-1 impairs cerebrovascular reserve capacity in an arteriogenesis model in mice.

Biomed Res Int 2013 20;2013:802149. Epub 2013 Aug 20.

Center for Cardiovascular Research (CCR), Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité-University Medicine Berlin, Hessische Straße 3-4, 10115 Berlin, Germany.

Collateral growth, arteriogenesis, represents a proliferative mechanism involving endothelial cells, smooth muscle cells, and monocytes/macrophages. Here we investigated the role of Density-Enhanced Phosphatase-1 (DEP-1) in arteriogenesis in vivo, a protein-tyrosine-phosphatase that has controversially been discussed with regard to vascular cell biology. Wild-type C57BL/6 mice subjected to permanent left common carotid artery occlusion (CCAO) developed a significant diameter increase in distinct arteries of the circle of Willis, especially in the anterior cerebral artery. Analyzing the impact of loss of DEP-1 function, induction of collateralization was quantified after CCAO and hindlimb femoral artery ligation comparing wild-type and DEP-1(-/-) mice. Both cerebral collateralization assessed by latex perfusion and peripheral vessel growth in the femoral artery determined by microsphere perfusion and micro-CT analysis were not altered in DEP-1(-/-) compared to wild-type mice. Cerebrovascular reserve capacity, however, was significantly impaired in DEP-1(-/-) mice. Cerebrovascular transcriptional analysis of proarteriogenic growth factors and receptors showed specifically reduced transcripts of PDGF-B. SiRNA knockdown of DEP-1 in endothelial cells in vitro also resulted in significant PDGF-B downregulation, providing further evidence for DEP-1 in PDGF-B gene regulation. In summary, our data support the notion of DEP-1 as positive functional regulator in vascular cerebral arteriogenesis, involving differential PDGF-B gene expression.
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http://dx.doi.org/10.1155/2013/802149DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3763586PMC
April 2014

Proprotein convertase subtilisin/kexin type 3 promotes adipose tissue-driven macrophage chemotaxis and is increased in obesity.

PLoS One 2013 6;8(8):e70542. Epub 2013 Aug 6.

Department of Medicine/Cardiology, Deutsches Herzzentrum Berlin, Berlin, Germany.

Background: Matrix metalloproteinase (MMP)-dependent extracellular matrix (ECM) remodeling is a key feature in cardiometabolic syndrome-associated adipogenesis and atherosclerosis. Activation of membrane-tethered (MT) 1-MMP depends on furin (PCSK3). However, the regulation and function of the natural furin-inhibitor serpinB8 and thus furin/MT1-MMP-activity in obesity-related tissue inflammation/remodeling is unknown. Here we aimed to determine the role of serpinB8/furin in obesity-associated chronic inflammation.

Methods And Results: Monocyte → macrophage transformation was characterized by decreases in serpinB8 and increases in furin/MT1-MMP. Rescue of serpinB8 by protein overexpression inhibited furin-dependent pro-MT1-MMP activation in macrophages, supporting its role as a furin-inhibitor. Obese white adipose tissue-facilitated macrophage migration was inhibited by furin- and MMP-inhibition, stressing the importance of the furin-MMP axis in fat tissue inflammation/remodeling. Monocytes from obese patients (body mass index (BMI) >30kg/m(2)) had higher furin, MT1-MMP, and resistin gene expression compared to normal weight individuals (BMI<25kg/m(2)) with significant correlations of BMI/furin and furin/MT1-MMP. In vitro, the adipocytokine resistin induced furin and MT1-MMP in mononuclear cells (MNCs), while MCP-1 had no effect.

Conclusions: Acquisition of the inflammatory macrophage phenotype is characterized by an imbalance in serpinB8/furin, leading to MT1-MMP activation, thereby enhancing migration. Increases in MT1-MMP and furin are present in MNCs from obese patients. Dissecting the regulation of furin and its inhibitor serpinB8 should facilitate targeting inflammation/remodeling in cardiometabolic diseases.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0070542PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3735592PMC
April 2014

Targeting density-enhanced phosphatase-1 (DEP-1) with antisense oligonucleotides improves the metabolic phenotype in high-fat diet-fed mice.

Cell Commun Signal 2013 Jul 26;11:49. Epub 2013 Jul 26.

Background: Insulin signaling is tightly controlled by tyrosine dephosphorylation of the insulin receptor through protein-tyrosine-phosphatases (PTPs). DEP-1 is a PTP dephosphorylating tyrosine residues in a variety of receptor tyrosine kinases. Here, we analyzed whether DEP-1 activity is differentially regulated in liver, skeletal muscle and adipose tissue under high-fat diet (HFD), examined the role of DEP-1 in insulin resistance in vivo, and its function in insulin signaling.

Results: Mice were fed an HFD for 10 weeks to induce obesity-associated insulin resistance. Thereafter, HFD mice were subjected to systemic administration of specific antisense oligonucleotides (ASOs), highly accumulating in hepatic tissue, against DEP-1 or control ASOs. Targeting DEP-1 led to improvement of insulin sensitivity, reduced basal glucose level, and significant reduction of body weight. This was accompanied by lower insulin and leptin serum levels. Suppression of DEP-1 in vivo also induced hyperphosphorylation in the insulin signaling cascade of the liver. Moreover, DEP-1 physically associated with the insulin receptor in situ, and recombinant DEP-1 dephosphorylated the insulin receptor in vitro.

Conclusions: These results indicate that DEP-1 acts as an endogenous antagonist of the insulin receptor, and downregulation of DEP-1 results in an improvement of insulin sensitivity. DEP-1 may therefore represent a novel target for attenuation of metabolic diseases.
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http://dx.doi.org/10.1186/1478-811X-11-49DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3734182PMC
July 2013

Cannabinoid receptor 1 inhibition improves cardiac function and remodelling after myocardial infarction and in experimental metabolic syndrome.

J Mol Med (Berl) 2013 Jul 1;91(7):811-23. Epub 2013 May 1.

Center for Cardiovascular Research (CCR) and Institute of Pharmacology, Charité-Universitätsmedizin, Hessische Strasse 3-4, 10115 Berlin, Germany.

The cannabinoid receptors, CB1 and CB2, are expressed in the heart, but their role under pathological conditions remains controversial. This study examined the effect of CB1 receptor blockade on cardiovascular functions after experimental MI and in experimental metabolic syndrome. MI was induced in Wistar rats by permanent ligation of the left coronary artery. Treatment with the CB1 receptor antagonist rimonabant (10 mg/kg i.p. daily) started 7 days before or 6 h after MI and continued for 6 weeks. Haemodynamic parameters were measured via echocardiography and intracardiac Samba catheter. CB1 blockade improved systolic and diastolic heart function, decreased cardiac collagen and hydroxyproline content and down-regulated TGF-β1. Additionally, rimonabant decreased arterial stiffness, normalised QRS complex duration and reduced brain natriuretic peptide levels in serum. In primary cardiac fibroblasts, rimonabant decreased MMP-9 activity and TGF-β1 expression. Furthermore, rimonabant improved depressed systolic function of spontaneously hypertensive obese rats and reduced weight gain. Blocking of CB1 receptor with rimonabant improves cardiac functions in the early and late stages after MI, decreases arterial stiffness and reduces cardiac remodelling. Rimonabant also has cardioprotective actions in rats characterised by the metabolic syndrome. Inhibition of proteolysis and TGF-β1 expression and reduced collagen content by rimonabant may attenuate destruction of the extracellular matrix and decrease fibrosis after MI.
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http://dx.doi.org/10.1007/s00109-013-1034-0DOI Listing
July 2013

Soluble P-selectin level correlates with acetylsalicylic acid but not with clopidogrel response in patients with stable coronary artery disease after a percutaneous coronary intervention.

Coron Artery Dis 2013 Jun;24(4):312-20

Department of Internal Medicine/Cardiology, German Heart Institute Berlin, 13353 Berlin, Germany.

Background: Impaired response to dual antiplatelet therapy is associated with worse cardiovascular outcome. Besides antiplatelet effects, there is evidence that both clopidogrel and acetylsalicylic acid (ASA) have anti-inflammatory properties. However, little is known about the relationship between platelet function and inflammation under dual antiplatelet therapy in patients with stable coronary artery disease.

Purpose: The purpose of the study was to investigate the correlation of platelet function with soluble (s)P-selectin and soluble (s)CD40L in patients undergoing elective percutaneous coronary intervention. Poor response to ASA and clopidogrel could lead to increased levels of inflammatory markers.

Methods: A total of 148 patients were included. Eighty percent of the patients were on 100 mg ASA and all patients were clopidogrel naive. They underwent percutaneous coronary intervention and received a loading dose of 600 mg clopidogrel. Platelet function was assessed by light transmittance aggregometry (LTA) and vasodilator-stimulated phosphoprotein analysis at baseline, 24 h after loading, and after 1 month of maintenance therapy, respectively. Plasma levels of sP-selectin and sCD40L were measured. To classify low responders to clopidogrel, patients were screened for genetic variants determining clopidogrel absorption and metabolization.

Results: sP-selectin levels correlated with LTA findings after stimulation with arachidonic acid (P=0.012). Further, in addition to decreased platelet reactivity observed on LTA, lower sP-selectin levels were seen in patients under ASA therapy (P=0.004). CYP2C19*2 allele carriers had a higher platelet reactivity after clopidogrel loading measured by adenosine diphosphate-induced aggregation in LTA (P=0.008) and vasodilator-stimulated phosphoprotein phosphorylation (P=0.035); however, there was no difference in the inflammatory markers. Multiple regression analysis showed that variables significantly related to sP-selectin plasma levels were sCD40L (P<0.001), LTA after stimulation with arachidonic acid (P<0.001), adenosine diphosphate (20 µmol/l, P=0.009), collagen (P<0.001), and ejection fraction (P=0.001).

Conclusion: sP-selectin was decreased in patients receiving ASA but did not reflect a CYP2C19*2-defined clopidogrel response. This underlines that sP-selectin is a useful marker for ASA, but not for clopidogrel response, in stable coronary artery disease.
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http://dx.doi.org/10.1097/MCA.0b013e328360efd3DOI Listing
June 2013