The Experts below are selected from a list of 375 Experts worldwide ranked by ideXlab platform
Richard L Whelan - One of the best experts on this subject based on the ideXlab platform.
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minimally invasive colorectal resection for cancer is associated with a short lived decrease in soluble tie 2 receptor levels which may transiently inhibit vegf mediated angiogenesis via altered blood levels of free ang 1 and ang 2
Surgical Endoscopy and Other Interventional Techniques, 2010Co-Authors: H Shantha M C Kumara, Michael J Grieco, Xiaohong Yan, Matthew F Kalady, Vincent Dimaggio, Donald G Kim, Neil Hyman, Daniel L Feingold, Richard L WhelanAbstract:Angiopoetin- (Ang-) 1 inhibits and Ang-2 promotes VEGF-mediated angiogenesis via binding to endothelial cell-bound Tie-2 receptor (Tie-2). After minimally invasive colorectal resection (MICR), Ang-1 levels decrease and Ang-2 levels increase, which may stimulate angiogenesis in wounds and residual tumor foci. Soluble Tie-2 (sTie-2) modulates the effects of free Ang-1 and Ang-2 by binding to them. This study assessed perioperative MICR plasma sTie-2 levels. Blood samples were taken preoperatively (PreOp) and on postoperative days (POD) 1 and 3 from 50 cancer and 53 benign disease MICR patients. In a subgroup, a fourth sample was taken between POD7 and POD13 and bundled as a single time point. sTie-2 levels (ng/ml) were determined via ELISA. The mean and SD were determined at each time point. The t test used for analysis. PreOp plasma sTie-2 levels were significantly higher in the benign group (27.6 ± 10.2) than in the cancer group (22.9 ± 7.9). A significant drop from PreOp occurred in sTie-2 levels in the cancer group on POD1 (20.0 ± 7.4) and POD3 (21.0 ± 6.6) and in the benign group on POD1 (24.8 ± 9.1). The benign group’s POD3 and the cancer group’s POD7-13 sTie-2 levels were statistically similar to the PreOp levels while the benign group’s POD7-13 level was significantly higher. PreOp sTie-2 levels were significantly lower in cancer patients. MICR is associated with a significant short-lived decrease in plasma sTie-2 levels in cancer patients on POD1 and 3, which may briefly inhibit VEGF-mediated angiogenesis. The benign group’s early results were similar.
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minimally invasive colorectal resection for cancer is associated with a short lived decrease in soluble tie 2 receptor levels which may transiently inhibit vegf mediated angiogenesis via altered blood levels of free ang 1 and ang 2
Surgical Endoscopy and Other Interventional Techniques, 2010Co-Authors: H Shantha M C Kumara, Michael J Grieco, Xiaohong Yan, Matthew F Kalady, Vincent Dimaggio, Donald G Kim, Neil Hyman, Daniel L Feingold, Richard L WhelanAbstract:Background Angiopoetin- (Ang-) 1 inhibits and Ang-2 promotes VEGF-mediated angiogenesis via binding to endothelial cell-bound Tie-2 receptor (Tie-2). After minimally invasive colorectal resection (MICR), Ang-1 levels decrease and Ang-2 levels increase, which may stimulate angiogenesis in wounds and residual tumor foci. Soluble Tie-2 (sTie-2) modulates the effects of free Ang-1 and Ang-2 by binding to them. This study assessed perioperative MICR plasma sTie-2 levels.
Rodney A Welch - One of the best experts on this subject based on the ideXlab platform.
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potentiation of c1 esterase inhibitor by stce a metalloprotease secreted by escherichia coli o157 h7
Journal of Experimental Medicine, 2004Co-Authors: Wyndham W Lathem, Tessa Bergsbaken, Rodney A WelchAbstract:The complement system is an essential component of host defense against pathogens. Previous research in our laboratory identified StcE, a metalloprotease secreted by Escherichia coli O157:H7 that cleaves the serpin C1 esterase inhibitor (C1-INH), a major regulator of the classical complement cascade. Analyses of StcE-treated C1-INH activity revealed that surprisingly, StcE enhanced the ability of C1-INH to inhibit the classical complement-mediated lysis of sheep erythrocytes. StcE directly interacts with both cells and C1-INH, thereby binding C1-INH to the cell surface. This suggests that the augmented activity of StcE-treated C1-INH is due to the increased concentration of C1-INH at the sites of potential lytic complex formation. Indeed, removal of StcE abolishes the ability of C1-INH to bind erythrocyte surfaces, whereas the proteolysis of C1-INH is unnecessary to potentiate its inhibitory activity. Physical analyses showed that StcE interacts with C1-INH within its aminoterminal domain, allowing the unaffected serpin domain to interact with its targets. In addition, StcE-treated C1-INH provides significantly increased serum resistance to E. coli K-12 over native C1-INH. These data suggest that by recruiting C1-INH to cell surfaces, StcE may protect both E. coli O157:H7 and the host cells to which the bacterium adheres from complement-mediated lysis and potentially damaging inflammatory events.
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acquisition of stce a c1 esterase inhibitor specific metalloprotease during the evolution of escherichia coli o157 h7
The Journal of Infectious Diseases, 2003Co-Authors: Wyndham W Lathem, Sarah E Witowski, Tessa Bergsbaken, Nicole T Perna, Rodney A WelchAbstract:Escherichia coli O157:H7 is a source of foodborne illness, causing diarrhea, hemorrhagic colitis, and hemolytic-uremic syndrome. E. coli O157:H7 secretes, via the etp type II secretion system, a metalloprotease, StcE, that specifically cleaves the serpin C1 esterase inhibitor. We determined by hybridization techniques the prevalence of stcE and etpD, a type II secretion gene, among diarrheagenic E. coli strains. stcE and etpD are ubiquitous among the O157:H7 serotype and are found in some enteropathogenic E. coli O55:H7 strains but are absent from other diarrheagenic E. coli. stcE was acquired on a large plasmid early in the evolution of E. coli O157:H7, before the inheritance of the Shiga toxin prophage. Other plasmidborne virulence factors, such as ehxA, katP, and espP, were acquired later by the enterohemorrhagic E. coli 1 complex in a stepwise manner. These data refine the sequential model of E. coli O157:H7 evolution proposed elsewhere.
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stce a metalloprotease secreted by escherichia coli o157 h7 specifically cleaves c1 esterase inhibitor
Molecular Microbiology, 2002Co-Authors: Wyndham W Lathem, Thomas E Grys, Sarah E Witowski, Alfredo G Torres, James B Kaper, Phillip I Tarr, Rodney A WelchAbstract:Escherichia coli O157:H7 causes diarrhoea, haemorrhagic colitis, and the haemolytic uraemic syndrome. We have identified a protein of previously unknown function encoded on the pO157 virulence plasmid of E. coli O157:H7, which is the first described protease that specifically cleaves C1 esterase inhibitor (C1-INH), a member of the serine protease inhibitor family. The protein, named StcE for secreted protease of C1 esterase inhibitor from EHEC (formerly Tagn), cleaves C1-INH to produce (unique) approximately 60-65 kDa fragments. StcE does not digest other serine protease inhibitors, extracellular matrix proteins or universal protease targets. We also observed that StcE causes the aggregation of cultured human T cells but not macrophage-like cells or B cells. Substitution of aspartic acid for glutamic acid at StcE position 435 within the consensus metalloprotease active site ablates its abilities to digest C1-INH and to aggregate T cells. StcE is secreted by the etp type II secretion pathway encoded on pO157, and extracellular StcE levels are positively regulated by the LEE-encoded regulator, Ler. StcE antigen and activity were detected in the faeces of a child with an E. coli O157:H7 infection, demonstrating the expression of StcE during human disease. Cleavage of C1-INH by StcE could plausibly cause localized pro-inflammatory and coagulation responses resulting in tissue damage, intestinal oedema and thrombotic abnormalities.
Wolfgang Lieb - One of the best experts on this subject based on the ideXlab platform.
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genome wide association study for endothelial growth factors
Circulation-cardiovascular Genetics, 2015Co-Authors: Wolfgang Lieb, Radwan Safa, Holly M Smith, Roberto Lorbeer, Alexander Teumer, Manja Koch, Minghuei Chen, Sebastian E Baumeister, Martin G Larson, Uwe VölkerAbstract:Background— Endothelial growth factors including angiopoietin-2 (Ang-2), its soluble receptor Tie-2 (sTie-2), and hepatocyte growth factor play important roles in angiogenesis, vascular remodeling, local tumor growth, and metastatic potential of various cancers. Circulating levels of these biomarkers have a heritable component (between 13% and 56%), but the underlying genetic variation influencing these biomarker levels is largely unknown. Methods and Results— We performed a genome-wide association study for circulating Ang-2, sTie-2, and hepatocyte growth factor in 3571 Framingham Heart Study participants and assessed replication of the top hits for Ang-2 and sTie-2 in 3184 participants of the Study of Health in Pomerania. In multivariable-adjusted models, sTie-2 and hepatocyte growth factor concentrations were associated with single-nucleotide polymorphisms in the genes encoding the respective biomarkers (top P =2.40×10−65 [rs2273720] and 3.64×10−19 [rs5745687], respectively). Likewise, rs2442517 in the MCPH1 gene (in which the Ang-2 gene is embedded) was associated with Ang-2 levels ( P =5.05×10−8 in Framingham Heart Study and 8.39×10−5 in Study of Health in Pomerania). Furthermore, single-nucleotide polymorphisms in the AB0 gene were associated with sTie-2 (top single-nucleotide polymorphism rs8176693 with P =1.84×10−33 in Framingham Heart Study; P =2.53×10−30 in Study of Health in Pomerania) and Ang-2 (rs8176746 with P =2.07×10−8 in Framingham Heart Study; P =0.001 in Study of Health in Pomerania) levels on a genome-wide significant level. The top genetic loci were explained between 1.7% (Ang-2) and 11.2% (sTie-2) of the interindividual variation in biomarker levels. Conclusions— Genetic variation contributes to the interindividual variation in growth factor levels and explains a modest proportion of circulating hepatocyte growth factor, Ang-2, and Tie-2. This may potentially contribute to the familial susceptibility to cancer, a premise that warrants further studies.
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genome wide association study for endothelial growth factors
Circulation-cardiovascular Genetics, 2015Co-Authors: Wolfgang Lieb, Radwan Safa, Holly M Smith, Roberto Lorbeer, Alexander Teumer, Manja Koch, Minghuei Chen, Sebastian E Baumeister, Martin G Larson, Uwe VölkerAbstract:Background— Endothelial growth factors including angiopoietin-2 (Ang-2), its soluble receptor Tie-2 (sTie-2), and hepatocyte growth factor play important roles in angiogenesis, vascular remodeling, local tumor growth, and metastatic potential of various cancers. Circulating levels of these biomarkers have a heritable component (between 13% and 56%), but the underlying genetic variation influencing these biomarker levels is largely unknown. Methods and Results— We performed a genome-wide association study for circulating Ang-2, sTie-2, and hepatocyte growth factor in 3571 Framingham Heart Study participants and assessed replication of the top hits for Ang-2 and sTie-2 in 3184 participants of the Study of Health in Pomerania. In multivariable-adjusted models, sTie-2 and hepatocyte growth factor concentrations were associated with single-nucleotide polymorphisms in the genes encoding the respective biomarkers (top P =2.40×10−65 [rs2273720] and 3.64×10−19 [rs5745687], respectively). Likewise, rs2442517 in the MCPH1 gene (in which the Ang-2 gene is embedded) was associated with Ang-2 levels ( P =5.05×10−8 in Framingham Heart Study and 8.39×10−5 in Study of Health in Pomerania). Furthermore, single-nucleotide polymorphisms in the AB0 gene were associated with sTie-2 (top single-nucleotide polymorphism rs8176693 with P =1.84×10−33 in Framingham Heart Study; P =2.53×10−30 in Study of Health in Pomerania) and Ang-2 (rs8176746 with P =2.07×10−8 in Framingham Heart Study; P =0.001 in Study of Health in Pomerania) levels on a genome-wide significant level. The top genetic loci were explained between 1.7% (Ang-2) and 11.2% (sTie-2) of the interindividual variation in biomarker levels. Conclusions— Genetic variation contributes to the interindividual variation in growth factor levels and explains a modest proportion of circulating hepatocyte growth factor, Ang-2, and Tie-2. This may potentially contribute to the familial susceptibility to cancer, a premise that warrants further studies.
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circulating angiopoietin 2 its soluble receptor tie 2 and mortality in the general population
Atherosclerosis, 2014Co-Authors: Roberto Lorbeer, Sebastian E Baumeister, Marcus Dorr, Matthias Nauck, Anne Grotevendt, Henry Volzke, Henri Wallaschofski, Ramachandran S Vasan, Wolfgang LiebAbstract:Aims To assess the association of circulating concentrations of angiopoietin-2 (Ang-2) and its soluble receptor Tie-2 (sTie-2) with all-cause, cardiovascular, and cancer mortality in a population-based sample. Methods and results Angiopoietin-2 and sTie-2 were measured in 3220 participants (1665 women; mean age 54.4 years) in the Study of Health in Pomerania (SHIP). Multivariable adjusted hazard ratios (HRs) for mortality were estimated using Cox proportional hazard models. During a median follow-up of 6.2 years, 217 participants died. Ang-2 levels were positively associated with all-cause mortality [HR 1.29; 95% confidence interval (CI) 1.19–1.39 per 1 SD increment; P < 0.001] and cardiovascular mortality (HR 1.32; 95% CI 1.18–1.49; P < 0.001), but not with cancer mortality (HR 1.08; 95% CI 0.89–1.32; P = 0.416). Levels of sTie-2 were not significantly related to all-cause mortality (HR 1.12; 95% CI 0.98–1.27; P = 0.102). Adding Ang-2 to a prediction model for all-cause mortality with standard risk factors slightly improved discrimination (Δ Harrell's C, 0.008; P < 0.001) but not risk reclassification (continuous net reclassification improvement, −0.015; P = 0.571). Conclusion In our community-based sample, higher serum Ang-2 concentrations were associated with greater risk for all-cause and cardiovascular mortality, suggesting that subtle increases in Ang-2 levels might reflect processes such as vascular remodelling that are associated with higher mortality risk. Adding Ang-2 to a mortality prediction model only modestly improved discrimination.
H Shantha M C Kumara - One of the best experts on this subject based on the ideXlab platform.
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minimally invasive colorectal resection for cancer is associated with a short lived decrease in soluble tie 2 receptor levels which may transiently inhibit vegf mediated angiogenesis via altered blood levels of free ang 1 and ang 2
Surgical Endoscopy and Other Interventional Techniques, 2010Co-Authors: H Shantha M C Kumara, Michael J Grieco, Xiaohong Yan, Matthew F Kalady, Vincent Dimaggio, Donald G Kim, Neil Hyman, Daniel L Feingold, Richard L WhelanAbstract:Angiopoetin- (Ang-) 1 inhibits and Ang-2 promotes VEGF-mediated angiogenesis via binding to endothelial cell-bound Tie-2 receptor (Tie-2). After minimally invasive colorectal resection (MICR), Ang-1 levels decrease and Ang-2 levels increase, which may stimulate angiogenesis in wounds and residual tumor foci. Soluble Tie-2 (sTie-2) modulates the effects of free Ang-1 and Ang-2 by binding to them. This study assessed perioperative MICR plasma sTie-2 levels. Blood samples were taken preoperatively (PreOp) and on postoperative days (POD) 1 and 3 from 50 cancer and 53 benign disease MICR patients. In a subgroup, a fourth sample was taken between POD7 and POD13 and bundled as a single time point. sTie-2 levels (ng/ml) were determined via ELISA. The mean and SD were determined at each time point. The t test used for analysis. PreOp plasma sTie-2 levels were significantly higher in the benign group (27.6 ± 10.2) than in the cancer group (22.9 ± 7.9). A significant drop from PreOp occurred in sTie-2 levels in the cancer group on POD1 (20.0 ± 7.4) and POD3 (21.0 ± 6.6) and in the benign group on POD1 (24.8 ± 9.1). The benign group’s POD3 and the cancer group’s POD7-13 sTie-2 levels were statistically similar to the PreOp levels while the benign group’s POD7-13 level was significantly higher. PreOp sTie-2 levels were significantly lower in cancer patients. MICR is associated with a significant short-lived decrease in plasma sTie-2 levels in cancer patients on POD1 and 3, which may briefly inhibit VEGF-mediated angiogenesis. The benign group’s early results were similar.
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minimally invasive colorectal resection for cancer is associated with a short lived decrease in soluble tie 2 receptor levels which may transiently inhibit vegf mediated angiogenesis via altered blood levels of free ang 1 and ang 2
Surgical Endoscopy and Other Interventional Techniques, 2010Co-Authors: H Shantha M C Kumara, Michael J Grieco, Xiaohong Yan, Matthew F Kalady, Vincent Dimaggio, Donald G Kim, Neil Hyman, Daniel L Feingold, Richard L WhelanAbstract:Background Angiopoetin- (Ang-) 1 inhibits and Ang-2 promotes VEGF-mediated angiogenesis via binding to endothelial cell-bound Tie-2 receptor (Tie-2). After minimally invasive colorectal resection (MICR), Ang-1 levels decrease and Ang-2 levels increase, which may stimulate angiogenesis in wounds and residual tumor foci. Soluble Tie-2 (sTie-2) modulates the effects of free Ang-1 and Ang-2 by binding to them. This study assessed perioperative MICR plasma sTie-2 levels.
Uwe Völker - One of the best experts on this subject based on the ideXlab platform.
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genome wide association study for endothelial growth factors
Circulation-cardiovascular Genetics, 2015Co-Authors: Wolfgang Lieb, Radwan Safa, Holly M Smith, Roberto Lorbeer, Alexander Teumer, Manja Koch, Minghuei Chen, Sebastian E Baumeister, Martin G Larson, Uwe VölkerAbstract:Background— Endothelial growth factors including angiopoietin-2 (Ang-2), its soluble receptor Tie-2 (sTie-2), and hepatocyte growth factor play important roles in angiogenesis, vascular remodeling, local tumor growth, and metastatic potential of various cancers. Circulating levels of these biomarkers have a heritable component (between 13% and 56%), but the underlying genetic variation influencing these biomarker levels is largely unknown. Methods and Results— We performed a genome-wide association study for circulating Ang-2, sTie-2, and hepatocyte growth factor in 3571 Framingham Heart Study participants and assessed replication of the top hits for Ang-2 and sTie-2 in 3184 participants of the Study of Health in Pomerania. In multivariable-adjusted models, sTie-2 and hepatocyte growth factor concentrations were associated with single-nucleotide polymorphisms in the genes encoding the respective biomarkers (top P =2.40×10−65 [rs2273720] and 3.64×10−19 [rs5745687], respectively). Likewise, rs2442517 in the MCPH1 gene (in which the Ang-2 gene is embedded) was associated with Ang-2 levels ( P =5.05×10−8 in Framingham Heart Study and 8.39×10−5 in Study of Health in Pomerania). Furthermore, single-nucleotide polymorphisms in the AB0 gene were associated with sTie-2 (top single-nucleotide polymorphism rs8176693 with P =1.84×10−33 in Framingham Heart Study; P =2.53×10−30 in Study of Health in Pomerania) and Ang-2 (rs8176746 with P =2.07×10−8 in Framingham Heart Study; P =0.001 in Study of Health in Pomerania) levels on a genome-wide significant level. The top genetic loci were explained between 1.7% (Ang-2) and 11.2% (sTie-2) of the interindividual variation in biomarker levels. Conclusions— Genetic variation contributes to the interindividual variation in growth factor levels and explains a modest proportion of circulating hepatocyte growth factor, Ang-2, and Tie-2. This may potentially contribute to the familial susceptibility to cancer, a premise that warrants further studies.
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genome wide association study for endothelial growth factors
Circulation-cardiovascular Genetics, 2015Co-Authors: Wolfgang Lieb, Radwan Safa, Holly M Smith, Roberto Lorbeer, Alexander Teumer, Manja Koch, Minghuei Chen, Sebastian E Baumeister, Martin G Larson, Uwe VölkerAbstract:Background— Endothelial growth factors including angiopoietin-2 (Ang-2), its soluble receptor Tie-2 (sTie-2), and hepatocyte growth factor play important roles in angiogenesis, vascular remodeling, local tumor growth, and metastatic potential of various cancers. Circulating levels of these biomarkers have a heritable component (between 13% and 56%), but the underlying genetic variation influencing these biomarker levels is largely unknown. Methods and Results— We performed a genome-wide association study for circulating Ang-2, sTie-2, and hepatocyte growth factor in 3571 Framingham Heart Study participants and assessed replication of the top hits for Ang-2 and sTie-2 in 3184 participants of the Study of Health in Pomerania. In multivariable-adjusted models, sTie-2 and hepatocyte growth factor concentrations were associated with single-nucleotide polymorphisms in the genes encoding the respective biomarkers (top P =2.40×10−65 [rs2273720] and 3.64×10−19 [rs5745687], respectively). Likewise, rs2442517 in the MCPH1 gene (in which the Ang-2 gene is embedded) was associated with Ang-2 levels ( P =5.05×10−8 in Framingham Heart Study and 8.39×10−5 in Study of Health in Pomerania). Furthermore, single-nucleotide polymorphisms in the AB0 gene were associated with sTie-2 (top single-nucleotide polymorphism rs8176693 with P =1.84×10−33 in Framingham Heart Study; P =2.53×10−30 in Study of Health in Pomerania) and Ang-2 (rs8176746 with P =2.07×10−8 in Framingham Heart Study; P =0.001 in Study of Health in Pomerania) levels on a genome-wide significant level. The top genetic loci were explained between 1.7% (Ang-2) and 11.2% (sTie-2) of the interindividual variation in biomarker levels. Conclusions— Genetic variation contributes to the interindividual variation in growth factor levels and explains a modest proportion of circulating hepatocyte growth factor, Ang-2, and Tie-2. This may potentially contribute to the familial susceptibility to cancer, a premise that warrants further studies.
