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Haeme Oxidised Soluble Guanylate Cyclase: A Novel Target for Vasorelaxation
Abstracts
S163
however, show significantly greater TF activity than lean controls, and this is related to serum hs-CRP. Thus, inflammation could contribute to a higher risk of thrombosis in obesity. doi:10.1016/j.hlc.2007.06.406 402 Haeme Oxidised Soluble Guanylate Cyclase: A Novel Target for Vasorelaxation H. Schmidt 1,2 , J. Luk 1,2 , J. Favaloro 1,2,∗ , J. Stasch 1,2 , B. Kemp-Harper 1,2 1 Department of Pharmacology & Centre for Vascular Health, Monash University, Melbourne, Australia; 2 Bayer HealthCare, Wuppertal, Germany
Conclusion: Enoxaparin has a more stable and reproducible anticoagulant effect suggesting that it should be considered as the anticoagulant of choice for prolonged or complex coronary angiography. doi:10.1016/j.hlc.2007.06.405 Basic Science – Vascular – Posters 401 The Effect of Obesity on Monocyte Tissue Factor activity J. Ayer ∗ , C.J. Song, D.S. Celermajer, S.B. Freedman The Royal Prince Alfred Hospital and The Anzac Research Institute, University of Sydney, Sydney, Australia Introduction: Obesity has been linked with increased thrombotic risk. It is not known whether inflammatory mediation of thrombosis through induction of monocyte tissue factor (TF), the main cellular trigger of thrombosis, may play a role. Methods: From obese (BMI ¿ 30, mean BMI 48.8, n = 6) and lean (BMI 20–25, mean BMI 23.4, n = 6) volunteers, age and gender matched, mean age 25 years, peripheral blood mononuclear cells (PBMC) were isolated and cultured for 4 h unstimulated, or with serum amyloid A (SAA 1, 25, 250 ng/ml), or lipopolysaccharide (LPS, 100 ng/ml). Serum hs-CRP was measured and correlated with unstimulated and induced monocyte TF activity. TF activity was measured by a one-stage plasma recalcification assay. Results: Unstimulated TF from obese subjects was significantly greater than in lean subjects (110 ± 28 mU versus 41 ± 6 mU TF/106 PBMC, p = 0.03). There were no significant differences in induced TF between the two groups for any stimulant. Serum hs-CRP was significantly higher in the obese than the lean group (7.0 ± 1.5 mg/L versus 0.63 ± 0.28 mg/L, p = 0.002) and there was a significant overall correlation between hs-CRP and TF activity (r = 0.68, p = 0.02). Conclusions: Whilst SAA and LPS are rapid and potent inducers of TF, induction is identical in obese and lean subjects. Unstimulated monocytes from obese subjects,
The nitric oxide (NO) receptor, sGC exists in the NO-sensitive reduced (Fe2+ ) state and NO-insensitive oxidised (Fe3+ )/haeme-free form. We hypothesised that in the resistance vasculature the ratio of these redox forms of sGC is altered with oxidative stress. Rat small mesenteric arteries were mounted in myographs, precontracted (∼50%) with U46619 and concentration–response curves to sGC activators which selectively target sGC in its Fe2+ (DEA/NO), Fe3+ (BAY 58-2667) and haeme-free states (BAY 58-2667, PPIX) were examined. BAY 58-2667 was most potent (pEC50 = 12.82 ± 0.13, Rmax : 91.9 ± 1.9%, n = 6) and its potency increased 200-fold (P < 0.0001) upon oxidation of sGC by ODQ (10 M, n = 6) and in the presence of the NO synthase inhibitor, L-NAME (100 M, n = 4). ODQ also enhanced vasorelaxation to PPIX yet impaired vasorelaxation to DEA/NO (control pEC50 = 7.24 ± 0.11 versus ODQ pEC50 = 5.68 ± 0.08, n = 5–10, P < 0.0001). Zn-PPIX (3 and 10 M), an inhibitor of haeme-free sGC, shifted the response to BAY 582667 and decreased its potency 30- (P = 0.0001, n = 6) and 3000-fold (P < 0.0001, n = 6), respectively. Relaxation to PPIX (pEC50 = 5.31 ± 0.57, Rmax = 55.5 ± 5.8%) was abolished by 3 M Zn-PPIX (P < 0.0001) yet vasorelaxation to DEA/NO was unchanged. These data suggest that a pool of oxidised/haeme-free sGC exists in the resistance vasculature under physiological conditions and this pool may be increased during oxidative stress and with reduced endogenous NO. This establishes activation of selective redox forms of sGC as a novel pharmacological approach to vasodilator therapy. doi:10.1016/j.hlc.2007.06.407 403 Vasorelaxation by Hydrogen Sulphide in the Mouse Mesenteric Artery J. Favaloro ∗ , E. Fiske, R. King, H. Schmidt Department of Pharmacology & Centre for Vascular Health, Monash University, Melbourne, Australia Hydrogen sulphide (H2 S) is best known for its distinctive “rotten egg” smell and is generally regarded as
ABSTRACTS
Heart, Lung and Circulation 2007;16:S1–S201
S163
however, show significantly greater TF activity than lean controls, and this is related to serum hs-CRP. Thus, inflammation could contribute to a higher risk of thrombosis in obesity. doi:10.1016/j.hlc.2007.06.406 402 Haeme Oxidised Soluble Guanylate Cyclase: A Novel Target for Vasorelaxation H. Schmidt 1,2 , J. Luk 1,2 , J. Favaloro 1,2,∗ , J. Stasch 1,2 , B. Kemp-Harper 1,2 1 Department of Pharmacology & Centre for Vascular Health, Monash University, Melbourne, Australia; 2 Bayer HealthCare, Wuppertal, Germany
Conclusion: Enoxaparin has a more stable and reproducible anticoagulant effect suggesting that it should be considered as the anticoagulant of choice for prolonged or complex coronary angiography. doi:10.1016/j.hlc.2007.06.405 Basic Science – Vascular – Posters 401 The Effect of Obesity on Monocyte Tissue Factor activity J. Ayer ∗ , C.J. Song, D.S. Celermajer, S.B. Freedman The Royal Prince Alfred Hospital and The Anzac Research Institute, University of Sydney, Sydney, Australia Introduction: Obesity has been linked with increased thrombotic risk. It is not known whether inflammatory mediation of thrombosis through induction of monocyte tissue factor (TF), the main cellular trigger of thrombosis, may play a role. Methods: From obese (BMI ¿ 30, mean BMI 48.8, n = 6) and lean (BMI 20–25, mean BMI 23.4, n = 6) volunteers, age and gender matched, mean age 25 years, peripheral blood mononuclear cells (PBMC) were isolated and cultured for 4 h unstimulated, or with serum amyloid A (SAA 1, 25, 250 ng/ml), or lipopolysaccharide (LPS, 100 ng/ml). Serum hs-CRP was measured and correlated with unstimulated and induced monocyte TF activity. TF activity was measured by a one-stage plasma recalcification assay. Results: Unstimulated TF from obese subjects was significantly greater than in lean subjects (110 ± 28 mU versus 41 ± 6 mU TF/106 PBMC, p = 0.03). There were no significant differences in induced TF between the two groups for any stimulant. Serum hs-CRP was significantly higher in the obese than the lean group (7.0 ± 1.5 mg/L versus 0.63 ± 0.28 mg/L, p = 0.002) and there was a significant overall correlation between hs-CRP and TF activity (r = 0.68, p = 0.02). Conclusions: Whilst SAA and LPS are rapid and potent inducers of TF, induction is identical in obese and lean subjects. Unstimulated monocytes from obese subjects,
The nitric oxide (NO) receptor, sGC exists in the NO-sensitive reduced (Fe2+ ) state and NO-insensitive oxidised (Fe3+ )/haeme-free form. We hypothesised that in the resistance vasculature the ratio of these redox forms of sGC is altered with oxidative stress. Rat small mesenteric arteries were mounted in myographs, precontracted (∼50%) with U46619 and concentration–response curves to sGC activators which selectively target sGC in its Fe2+ (DEA/NO), Fe3+ (BAY 58-2667) and haeme-free states (BAY 58-2667, PPIX) were examined. BAY 58-2667 was most potent (pEC50 = 12.82 ± 0.13, Rmax : 91.9 ± 1.9%, n = 6) and its potency increased 200-fold (P < 0.0001) upon oxidation of sGC by ODQ (10 M, n = 6) and in the presence of the NO synthase inhibitor, L-NAME (100 M, n = 4). ODQ also enhanced vasorelaxation to PPIX yet impaired vasorelaxation to DEA/NO (control pEC50 = 7.24 ± 0.11 versus ODQ pEC50 = 5.68 ± 0.08, n = 5–10, P < 0.0001). Zn-PPIX (3 and 10 M), an inhibitor of haeme-free sGC, shifted the response to BAY 582667 and decreased its potency 30- (P = 0.0001, n = 6) and 3000-fold (P < 0.0001, n = 6), respectively. Relaxation to PPIX (pEC50 = 5.31 ± 0.57, Rmax = 55.5 ± 5.8%) was abolished by 3 M Zn-PPIX (P < 0.0001) yet vasorelaxation to DEA/NO was unchanged. These data suggest that a pool of oxidised/haeme-free sGC exists in the resistance vasculature under physiological conditions and this pool may be increased during oxidative stress and with reduced endogenous NO. This establishes activation of selective redox forms of sGC as a novel pharmacological approach to vasodilator therapy. doi:10.1016/j.hlc.2007.06.407 403 Vasorelaxation by Hydrogen Sulphide in the Mouse Mesenteric Artery J. Favaloro ∗ , E. Fiske, R. King, H. Schmidt Department of Pharmacology & Centre for Vascular Health, Monash University, Melbourne, Australia Hydrogen sulphide (H2 S) is best known for its distinctive “rotten egg” smell and is generally regarded as
ABSTRACTS
Heart, Lung and Circulation 2007;16:S1–S201