Markus Roth

Publications of Markus Roth

• Inducible NOS inhibition reverses tobacco-smoke-induced emphysema and pulmonary hypertension in mice.

  Authors: Michael Seimetz, Nirmal Parajuli, Alexandra Pichl, Florian Veit, Grazyna Kwapiszewska, Friederike C Weisel, Katrin Milger, Bakytbek Egemnazarov, Agnieszka Turowska, Beate Fuchs [......] Peter Jaksch, Rio Dumitrascu, Holger Garn, Robert Voswinckel, Sawa Kostin, Werner Seeger, Ralph T Schermuly, Friedrich Grimminger, Hossein A Ghofrani, Norbert Weissmann

  Cell. 10/2011; 147(2):293-305.

  Chronic obstructive pulmonary disease (COPD) is one of the most common causes of death worldwide. We report in an emphysema model of mice chronically exposed to tobacco smoke that pulmonary vascularChronic obstructive pulmonary disease (COPD) is one of the most common causes of death worldwide. We report in an emphysema model of mice chronically exposed to tobacco smoke that pulmonary vascular dysfunction, vascular remodeling, and pulmonary hypertension (PH) precede development of alveolar destruction. We provide evidence for a causative role of inducible nitric oxide synthase (iNOS) and peroxynitrite in this context. Mice lacking iNOS were protected against emphysema and PH. Treatment of wild-type mice with the iNOS inhibitor N(6)-(1-iminoethyl)-L-lysine (L-NIL) prevented structural and functional alterations of both the lung vasculature and alveoli and also reversed established disease. In chimeric mice lacking iNOS in bone marrow (BM)-derived cells, PH was dependent on iNOS from BM-derived cells, whereas emphysema development was dependent on iNOS from non-BM-derived cells. Similar regulatory and structural alterations as seen in mouse lungs were found in lung tissue from humans with end-stage COPD.

• Heme Oxygenase-2 and Large-conductance Ca2+ activated K+ Channels: Lung Vascular Effects of Hypoxia.

  Authors: Markus Roth, Markus Rupp, Simone Hofmann, Manish Mittal, Beate Fuchs, Natascha Sommer, Nirmal Parajuli, Karin Quanz, Dominic Schubert, Eva Dony, Ralph Theo Schermuly, Hossein Ardeschir Ghofrani, Ulrike Sausbier, Katrin Rutschmann, Sarah Wilhelm, Werner Seeger, Peter Ruth, Friedrich Grimminger, Matthias Sausbier, Norbert Weissmann

  American journal of respiratory and critical care medicine. 07/2009;

  RATIONALE: Hypoxic pulmonary vasoconstriction (HPV) is an important mechanism by which pulmonary gas exchange is optimized by the adaptation of blood flow to alveolar ventilation. In chronic hypoxia,RATIONALE: Hypoxic pulmonary vasoconstriction (HPV) is an important mechanism by which pulmonary gas exchange is optimized by the adaptation of blood flow to alveolar ventilation. In chronic hypoxia, in addition to HPV a vascular remodeling process leads to pulmonary hypertension. Recently, a complex of heme oxygenase-2 (HO-2) and the BK channel has been suggested as a universal oxygen sensor system. OBJECTIVE: We investigated, whether this complex serves as an oxygen sensor for the vascular effects of alveolar hypoxia in the lung. METHODS and RESULTS: Immunohistochemical analysis of mouse lungs identified HO-2 mainly in pulmonary arteries, the bronchial epithelium and alveolar epithelial cells. BK channel alpha-subunit (BKalpha) immunoreactivity was found primarily in the bronchial and vascular smooth muscle layer. Immunofluorescence staining and co-immunoprecipitation suggested only a weak complexation of HO-2 and BKalpha in pulmonary arterial smooth muscle cells. The strength of acute and sustained HPV, determined in isolated perfused and ventilated lungs, was not different between the wild-type, HO-2- and BKalpha-deficient mice. Exposure of mice to three weeks of chronic hypoxia resulted in a slight downregulation of HO-2 and no alteration in BKalpha expression. The degree of pulmonary hypertension which developed, quantified from right ventricular pressure, right heart hypertrophy, and the degree of muscularization of precapillary pulmonary arteries, was not different between the wild-type, HO-2- or BKalpha-deficient mice. CONCLUSION: It is demonstrated that neither deletion of HO-2 nor BK channels affects the acute, sustained and chronic vascular responses to alveolar hypoxia in the lung.

• Hypoxia-induced pulmonary hypertension: different impact of iloprost, sildenafil, and nitric oxide.

  Authors: Norbert Weissmann, Boris Gerigk, Ozlem Kocer, Matthias Nollen, Sascha Hackemack, Hossein Ardeschir Ghofrani, Ralph Theo Schermuly, Ghazwan Butrous, Andreas Schulz, Markus Roth, Werner Seeger, Friedrich Grimminger

  Respiratory medicine. 11/2007; 101(10):2125-32.

  OBJECTIVES: Chronic alveolar hypoxia induces pulmonary hypertension, evident from elevated pulmonary artery pressure (PAP), pulmonary vascular resistance, right ventricular hypertrophy (RVH), andOBJECTIVES: Chronic alveolar hypoxia induces pulmonary hypertension, evident from elevated pulmonary artery pressure (PAP), pulmonary vascular resistance, right ventricular hypertrophy (RVH), and increased muscularization of the pulmonary vasculature. Additionally, the vasoconstrictor response to acute hypoxia (HPV) may be reduced in the remodeled vasculature. However, no direct comparison of different treatments on the various parameters characterizing pulmonary hypertension has been performed yet. Against this background, we compared the effects of inhaled NO, infused iloprost, a stable prostacyclin analogue, and oral sildenafil, a phosphodiesterase 5 inhibitor, on hypoxia-induced pulmonary hypertension. METHODS: Exposure of rabbits to chronic hypoxia (FiO(2)=0.10) for 42 days. Treatment with infused iloprost, oral sildenafil, and inhaled nitric oxide. RESULTS: We quantified PAP, pulmonary vascular resistance, RVH, vascular remodeling, vasoreactivity, and the strength of HPV. Chronic hypoxia resulted in an increase in (a) the right ventricle/(left ventricle+septum) ratio from 0.26+/-0.01 to 0.44+/-0.01, (b) PAP, and (c) the degree of muscularization from 14.0+/-4.0% to 43.5+/-5.3%. Treatment with iloprost and sildenafil, but not with NO, prevented the increase in muscularization. In contrast, RVH was strongly inhibited by sildenafil, whereas NO had some minor, and iloprost had no effect. Only iloprost reduced PAP compared to NO and sildenafil. The downregulation of HPV was abrogated only by NO. CONCLUSION: We demonstrated (a) that the parameters characterizing hypoxia-induced pulmonary hypertension are not functionally linked, (b) that the downregulation of HPV under chronic hypoxia can be prevented by inhaled NO but not by sildenafil and iloprost, and (c) that iloprost is particularly effective in preventing vascular remodeling and sildenafil in preventing RVH.

• Hypoxia-dependent regulation of nonphagocytic NADPH oxidase subunit NOX4 in the pulmonary vasculature.

  Authors: Manish Mittal, Markus Roth, Peter König, Simone Hofmann, Eva Dony, Parag Goyal, Anne-Christin Selbitz, Ralph Theo Schermuly, Hossein Ardeschir Ghofrani, Grazyna Kwapiszewska, Wolfgang Kummer, Walter Klepetko, Mir Ali Reza Hoda, Ludger Fink, Jörg Hänze, Werner Seeger, Friedrich Grimminger, Harald H H W Schmidt, Norbert Weissmann

  Circulation research. 09/2007; 101(3):258-67.

  Nonphagocytic NADPH oxidases have recently been suggested to play a major role in the regulation of physiological and pathophysiological processes, in particular, hypertrophy, remodeling, andNonphagocytic NADPH oxidases have recently been suggested to play a major role in the regulation of physiological and pathophysiological processes, in particular, hypertrophy, remodeling, and angiogenesis in the systemic circulation. Moreover, NADPH oxidases have been suggested to serve as oxygen sensors in the lung. Chronic hypoxia induces vascular remodeling with medial hypertrophy leading to the development of pulmonary hypertension. We screened lung tissue for the expression of NADPH oxidase subunits. NOX1, NOXA1, NOXO1, p22phox, p47phox, p40phox, p67phox, NOX2, and NOX4 were present in mouse lung tissue. Comparing mice maintained for 21 days under hypoxic (10% O(2)) or normoxic (21% O(2)) conditions, an upregulation exclusively of NOX4 mRNA was observed under hypoxia in homogenized lung tissue, concomitant with increased levels in microdissected pulmonary arterial vessels. In situ hybridization and immunohistological staining for NOX4 in mouse lungs revealed a localization of NOX4 mRNA and protein predominantly in the media of small pulmonary arteries, with increased labeling intensities after chronic exposure to hypoxia. In isolated pulmonary arterial smooth muscle cells (PASMCs), NOX4 was localized primarily to the perinuclear space and its expression levels were increased after exposure to hypoxia. Treatment of PASMCs with siRNA directed against NOX4 decreased NOX4 mRNA levels and reduced PASMC proliferation as well as generation of reactive oxygen species. In lungs from patients with idiopathic pulmonary arterial hypertension (IPAH), expression levels of NOX4, which was localized in the vessel media, were 2.5-fold upregulated. These results support an important role for NOX4 in the vascular remodeling associated with development of pulmonary hypertension.

• Reversal of experimental pulmonary hypertension by PDGF inhibition.

  Authors: Ralph Theo Schermuly, Eva Dony, Hossein Ardeschir Ghofrani, Soni Pullamsetti, Rajkumar Savai, Markus Roth, Akylbek Sydykov, Ying-Ju Lai, Norbert Weissmann, Werner Seeger, Friedrich Grimminger

  The Journal of clinical investigation. 11/2005; 115(10):2811-21.

  Progression of pulmonary hypertension is associated with increased proliferation and migration of pulmonary vascular smooth muscle cells. PDGF is a potent mitogen and involved in this process. We nowProgression of pulmonary hypertension is associated with increased proliferation and migration of pulmonary vascular smooth muscle cells. PDGF is a potent mitogen and involved in this process. We now report that the PDGF receptor antagonist STI571 (imatinib) reversed advanced pulmonary vascular disease in 2 animal models of pulmonary hypertension. In rats with monocrotaline-induced pulmonary hypertension, therapy with daily administration of STI571 was started 28 days after induction of the disease. A 2-week treatment resulted in 100% survival, compared with only 50% in sham-treated rats. The changes in RV pressure, measured continuously by telemetry, and right heart hypertrophy were reversed to near-normal levels. STI571 prevented phosphorylation of the PDGF receptor and suppressed activation of downstream signaling pathways. Similar results were obtained in chronically hypoxic mice, which were treated with STI571 after full establishment of pulmonary hypertension. Moreover, expression of the PDGF receptor was found to be significantly increased in lung tissue from pulmonary arterial hypertension patients compared with healthy donor lung tissue. We conclude that STI571 reverses vascular remodeling and cor pulmonale in severe experimental pulmonary hypertension regardless of the initiating stimulus. This regimen offers a unique novel approach for antire-modeling therapy in progressed pulmonary hypertension.