1
|
Toney BM, Fisher AJ, Albrecht M, Lockett AD, Presson RG, Petrache I, Lahm T. Selective endothelin-A receptor blockade attenuates endotoxin-induced pulmonary hypertension and pulmonary vascular dysfunction. Pulm Circ 2014; 4:300-10. [PMID: 25006449 DOI: 10.1086/675993] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 01/16/2014] [Indexed: 01/07/2023] Open
Abstract
Endothelin-1 is a potent mediator of sepsis-induced pulmonary hypertension (PH). The pulmonary vascular effects of selective blockade of endothelin receptor subtype A (ETAR) during endotoxemia remain unknown. We hypothesized that selective ETAR antagonism attenuates endotoxin-induced PH and improves pulmonary artery (PA) vasoreactivity. Adult male Sprague-Dawley rats (250-450 g) received lipopolysaccharide (LPS; Salmonella typhimurium; 20 mg/kg intraperitoneally) or vehicle 6 hours before hemodynamic assessment and tissue harvest. The selective ETAR antagonist sitaxsentan (10 or 20 mg/kg) or vehicle was injected intravenously 3 hours after receipt of LPS. Right ventricular systolic pressure, mean arterial pressure (MAP), cardiac output (CO), oxygenation (P/F ratio), and serum bicarbonate were measured. Bronchoalveolar lavage (BAL) cell differential and lung wet-to-dry ratios were obtained. Endothelium-dependent and endothelium-independent vasorelaxations were determined in isolated PA rings. PA interleukin (IL)-1β, IL-6, tumor necrosis factor α (TNF-α), and inducible nitric oxide synthase (iNOS) messenger RNA (mRNA) were measured. LPS caused PH, decreased MAP, CO, and serum bicarbonate, and increased PA IL-1β, IL-6, TNF-α, and iNOS mRNA. Sitaxsentan attenuated sepsis-induced PH and increased MAP. The P/F ratio, CO, serum bicarbonate, and BAL neutrophilia were not affected by sitaxsentan. In isolated PA rings, while not affecting phenylephrine-induced vasocontraction or endothelium-dependent relaxation, sitaxsentan dose-dependently attenuated LPS-induced alterations in endothelium-independent relaxation. PA cytokine mRNA levels were not significantly attenuated by ETAR blockade. We conclude that ETAR blockade attenuates endotoxin-induced alterations in systemic and PA pressures without negatively affecting oxygenation. This protective effect appears to be mediated not by attenuation of sepsis-induced cardiac dysfunction, acidosis, or alveolar inflammation but rather by improved endothelium-independent vasorelaxation.
Collapse
Affiliation(s)
- Brent M Toney
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care, Occupational and Sleep Medicine, Indiana University, Indianapolis, Indiana, USA
| | - Amanda J Fisher
- Department of Anesthesiology, Indiana University, Indianapolis, Indiana, USA
| | - Marjorie Albrecht
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care, Occupational and Sleep Medicine, Indiana University, Indianapolis, Indiana, USA
| | - Angelia D Lockett
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care, Occupational and Sleep Medicine, Indiana University, Indianapolis, Indiana, USA
| | - Robert G Presson
- Department of Anesthesiology, Indiana University, Indianapolis, Indiana, USA ; Center for Immunobiology, Indiana University, Indianapolis, Indiana, USA
| | - Irina Petrache
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care, Occupational and Sleep Medicine, Indiana University, Indianapolis, Indiana, USA ; Center for Immunobiology, Indiana University, Indianapolis, Indiana, USA ; Roudebush Veterans Affairs Medical Center, Indianapolis, Indiana, USA
| | - Tim Lahm
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care, Occupational and Sleep Medicine, Indiana University, Indianapolis, Indiana, USA ; Center for Immunobiology, Indiana University, Indianapolis, Indiana, USA ; Roudebush Veterans Affairs Medical Center, Indianapolis, Indiana, USA
| |
Collapse
|
2
|
Lahm T, Crisostomo PR, Markel TA, Wang M, Wang Y, Tan J, Meldrum DR. Selective estrogen receptor-alpha and estrogen receptor-beta agonists rapidly decrease pulmonary artery vasoconstriction by a nitric oxide-dependent mechanism. Am J Physiol Regul Integr Comp Physiol 2008; 295:R1486-93. [PMID: 18832085 DOI: 10.1152/ajpregu.90667.2008] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Both endogenous and exogenous estrogen decrease pulmonary artery (PA) vasoconstriction. Whether these effects are mediated via estrogen receptor (ER)-alpha or ER-beta, and whether the contribution of ERs is stimulus-dependent, remains unknown. We hypothesized that administration of the selective ER-alpha agonist propylpyrazole triol (PPT) and/or the selective ER-beta agonist diarylpropiolnitrile (DPN) rapidly decreases PA vasoconstriction induced by pharmacologic and hypoxic stimuli via a nitric oxide (NO)-dependent mechanism. PA rings (n = 3-10/group) from adult male Sprague-Dawley rats were suspended in physiologic organ baths. Force displacement was measured. Vasoconstrictor responses to phenylephrine (10(-8)M - 10(-5)M) and hypoxia (Po(2) 35-45 mmHg) were determined. Endothelium-dependent and -independent vasorelaxation were measured by generating dose-response curves to acetylcholine (10(-8)M - 10(-4)M) and sodium nitroprusside (10(-9)M - 10(-5)M). PPT or DPN (10(-9)M - 5 x 10(-5)M) were added to the organ bath in the presence and absence of the NO-synthase inhibitor N(omega)-nitro-l-arginine methyl ester (l-NAME) (10(-4)M). Selective ER-alpha activation (PPT, 5 x 10(-5)M) rapidly (<20 min) decreased phenylephrine-induced vasoconstriction. This effect, as well as PPT's effects on endothelium-dependent vasorelaxation, were neutralized by l-NAME. In contrast, selective ER-beta activation (DPN, 5 x 10(-5)M) rapidly decreased phase II of hypoxic pulmonary vasoconstriction (HPV). l-NAME eliminated this phenomenon. Lower PPT or DPN concentrations were less effective. We conclude that both ER-alpha and ER-beta decrease PA vasoconstriction. The immediate onset of effect suggests a nongenomic mechanism. The contribution of specific ERs appears to be stimulus specific, with ER-alpha primarily modulating phenylephrine-induced vasoconstriction, and ER-beta inhibiting HPV. NO inhibition eliminates these effects, suggesting a central role for NO in mediating the pulmonary vascular effects of both ER-alpha and ER-beta.
Collapse
Affiliation(s)
- Tim Lahm
- Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | | | | | | | | | | | | |
Collapse
|
4
|
Lu A, Frink M, Choudhry MA, Schwacha MG, Hubbard WJ, Rue LW, Bland KI, Chaudry IH. Mitochondria play an important role in 17beta-estradiol attenuation of H(2)O(2)-induced rat endothelial cell apoptosis. Am J Physiol Endocrinol Metab 2007; 292:E585-93. [PMID: 17018771 DOI: 10.1152/ajpendo.00413.2006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Studies have shown salutary effects of 17beta-estradiol following trauma-hemorrhage on different cell types. 17beta-Estradiol also induces improved circulation via relaxation of the aorta and has an anti-apoptotic effect on endothelial cells. Because mitochondria play a pivotal role in apoptosis, we hypothesized that 17beta-estradiol will maintain mitochondrial function and will have protective effects against H(2)O(2)-induced apoptosis in endothelial cells. Endothelial cells were isolated from rats' aorta and cultured in the presence or absence of H(2)O(2), a potent inducer of apoptosis. In additional studies, endothelial cells were pretreated with 17beta-estradiol. Flow cytometry analysis revealed H(2)O(2)-induced apoptosis in 80.9% of endothelial cells; however, prior treatment of endothelial cells with 17beta-estradiol resulted in an approximately 40% reduction in apoptosis. This protective effect of 17beta-estradiol was abrogated when endothelial cells were cultured in the presence ICI-182780, indicating the involvement of estrogen receptor (ER). Fluorescence microscopy revealed a 17beta-estradiol-mediated attenuation of H(2)O(2)-induced mitochondrial condensation. Western blot analysis demonstrated that H(2)O(2)-induced cytochrome c release from mitochondrion to cytosol and the activation of caspase-9 and -3 were decreased by 17beta-estradiol. These findings suggest that 17beta-estradiol attenuated H(2)O(2)-induced apoptosis via ER-dependent activation of caspase-9 and -3 in rat endothelial cells through mitochondria.
Collapse
Affiliation(s)
- Ailing Lu
- Center for Surgical Research, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | | | | | | | | | | | | | | |
Collapse
|