RESUMEN
Hypoxia-inducible factor 1α (HIF1α) is a master regulator of numerous biological processes under low oxygen tensions. Yet, the mechanisms and biological consequences of aerobic HIF1α activation by intrinsic factors, particularly in primary cells remain elusive. Here, we show that HIF1α signaling is activated in several human primary vascular cells under ambient oxygen tensions, and in vascular smooth muscle cells (VSMCs) of normal human lung tissue, which contributed to a relative resistance to further enhancement of glycolytic activity in hypoxia. Mechanistically, aerobic HIFα activation is mediated by paracrine secretion of three branched chain α-ketoacids (BCKAs), which suppress prolyl hydroxylase domain-containing protein 2 (PHD2) activity via direct inhibition and via lactate dehydrogenase A (LDHA)-mediated generation of L-2-hydroxyglutarate (L2HG). Metabolic dysfunction induced by BCKAs was observed in the lungs of rats with pulmonary arterial hypertension (PAH) and in pulmonary artery smooth muscle cells (PASMCs) from idiopathic PAH patients. BCKA supplementation stimulated glycolytic activity and promoted a phenotypic switch to the synthetic phenotype in PASMCs of normal and PAH subjects. In summary, we identify BCKAs as novel signaling metabolites that activate HIF1α signaling in normoxia and that the BCKA-HIF1α pathway modulates VSMC function and may be relevant to pulmonary vascular pathobiology.
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BACKGROUND: Elevated mean pulmonary artery pressure (mPAP) is common in patients with hypertrophic cardiomyopathy (HCM) and heart failure symptoms. However, dynamic left ventricular (LV) outflow tract obstruction may confound interpretation of pulmonary hypertension (PH) pathophysiologic features in HCM when relying on resting invasive hemodynamic data alone. RESEARCH QUESTION: Do structural changes to the lung vasculature clarify PH pathophysiologic features in patients with HCM with progressive heart failure? STUDY DESIGN AND METHODS: Clinical data and ultrarare lung autopsy specimens were acquired retrospectively from the National Institutes of Health (1975-1992). Patients were included based on the availability of lung tissue and recorded mPAP. Discarded tissue from rejected lung donors served as control specimens. Histomorphology was performed on pulmonary arterioles and veins. Comparisons were calculated using the Student t test and Mann-Whitney U test; Pearson correlation was used to assess association between morphometric measurements and HCM cardiac and hemodynamic measurements. RESULTS: The HCM cohort (n = 7; mean ± SD age, 43 ± 18 years; 71% men) showed maximum mean ± SD LV wall thickness of 25 ± 2.8 mm, mean ± SD outflow tract gradient of 90 ± 30 mm Hg, median mPAP of 25 mm Hg (interquartile range [IQR], 6 mm Hg), median pulmonary artery wedge pressure (PAWP) of 16 mm Hg (IQR, 4 mm Hg), and median pulmonary vascular resistance of 1.8 Wood units (WU; IQR, 2.4 WU). Compared with control samples (n = 5), patients with HCM showed greater indexed pulmonary arterial hypertrophy (20.7 ± 7.2% vs 49.7 ± 12%; P < .001) and arterial wall fibrosis (11.5 ± 3.4 mm vs 21.0 ± 4.7 mm; P < .0001), which correlated with mPAP (r = 0.84; P = .018), PAWP (r = 0.74; P = .05), and LV outflow tract gradient (r = 0.78; P = .035). Compared with control samples, pulmonary vein thickness was increased by 2.9-fold (P = .008) in the HCM group, which correlated with mPAP (r = 0.81; P = .03) and LV outflow tract gradient (r = 0.83; P = .02). INTERPRETATION: To the best of our knowledge, these data demonstrate for the first time that in patients with obstructive HCM, heart failure is associated with pathogenic pulmonary vascular remodeling even when mPAP is elevated only mildly. These observations clarify PH pathophysiologic features in HCM, with future implications for clinical strategies that mitigate outflow tract obstruction.
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Cardiomiopatía Hipertrófica , Insuficiencia Cardíaca , Hipertensión Pulmonar , Masculino , Humanos , Adulto , Persona de Mediana Edad , Femenino , Hipertensión Pulmonar/complicaciones , Estudios Retrospectivos , Remodelación Vascular , Cardiomiopatía Hipertrófica/complicaciones , Insuficiencia Cardíaca/complicacionesRESUMEN
Rationale: Data on the molecular mechanisms that regulate platelet-pulmonary endothelial adhesion under conditions of hypoxia are lacking, but may have important therapeutic implications. Objectives: To identify a hypoxia-sensitive, modifiable mediator of platelet-pulmonary artery endothelial cell adhesion and thrombotic remodeling. Methods: Network medicine was used to profile protein-protein interactions in hypoxia-treated human pulmonary artery endothelial cells. Data from liquid chromatography-mass spectrometry and microscale thermophoresis informed the development of a novel antibody (Ab) to inhibit platelet-endothelial adhesion, which was tested in cells from patients with chronic thromboembolic pulmonary hypertension (CTEPH) and three animal models in vivo. Measurements and Main Results: The protein NEDD9 was identified in the hypoxia thrombosome network in silico. Compared with normoxia, hypoxia (0.2% O2) for 24 hours increased HIF-1α (hypoxia-inducible factor-1α)-dependent NEDD9 upregulation in vitro. Increased NEDD9 was localized to the plasma-membrane surface of cells from control donors and patients with CTEPH. In endarterectomy specimens, NEDD9 colocalized with the platelet surface adhesion molecule P-selectin. Our custom-made anti-NEDD9 Ab targeted the NEDD9-P-selectin interaction and inhibited the adhesion of activated platelets to pulmonary artery endothelial cells from control donors in vitro and from patients with CTEPH ex vivo. Compared with control mice, platelet-pulmonary endothelial aggregates and pulmonary hypertension induced by ADP were decreased in NEDD9-/- mice or wild-type mice treated with the anti-NEDD9 Ab, which also decreased chronic pulmonary thromboembolic remodeling in vivo. Conclusions: The NEDD9-P-selectin protein-protein interaction is a modifiable target with which to inhibit platelet-pulmonary endothelial adhesion and thromboembolic vascular remodeling, with potential therapeutic implications for patients with disorders of increased hypoxia signaling pathways, including CTEPH.
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Proteínas Adaptadoras Transductoras de Señales/fisiología , Adhesión Celular/fisiología , Hipoxia/fisiopatología , Circulación Pulmonar/fisiología , Embolia Pulmonar/fisiopatología , Transducción de Señal/fisiología , Animales , Plaquetas/fisiología , Células Cultivadas/fisiología , Células Endoteliales/fisiología , Femenino , Humanos , Masculino , Ratones , Persona de Mediana Edad , Modelos AnimalesRESUMEN
Progress in precision medicine is limited by insufficient knowledge of transcriptomic or proteomic features in involved tissues that define pathobiological differences between patients. Here, myectomy tissue from patients with obstructive hypertrophic cardiomyopathy and heart failure is analyzed using RNA-Seq, and the results are used to develop individualized protein-protein interaction networks. From this approach, hypertrophic cardiomyopathy is distinguished from dilated cardiomyopathy based on the protein-protein interaction network pattern. Within the hypertrophic cardiomyopathy cohort, the patient-specific networks are variable in complexity, and enriched for 30 endophenotypes. The cardiac Janus kinase 2-Signal Transducer and Activator of Transcription 3-collagen 4A2 (JAK2-STAT3-COL4A2) expression profile informed by the networks was able to discriminate two hypertrophic cardiomyopathy patients with extreme fibrosis phenotypes. Patient-specific network features also associate with other important hypertrophic cardiomyopathy clinical phenotypes. These proof-of-concept findings introduce personalized protein-protein interaction networks (reticulotypes) for characterizing patient-specific pathobiology, thereby offering a direct strategy for advancing precision medicine.
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Cardiomiopatía Hipertrófica/patología , Redes Reguladoras de Genes , Medicina de Precisión , Estudios de Casos y Controles , Estudios de Cohortes , Endofenotipos , Fibrosis , Insuficiencia Cardíaca/genética , Humanos , Fenotipo , Mapas de Interacción de Proteínas/genética , Transducción de Señal , Transcriptoma/genéticaRESUMEN
Transcriptomic analysis of pulmonary microvascular endothelial cells from experimental models offers insight into pulmonary arterial hypertension (PAH) pathobiology. However, culturing may alter the molecular profile of endothelial cells prior to analysis, limiting the translational relevance of results. Here we present a novel and validated method for isolating RNA from pulmonary microvascular endothelial cells (PMVECs) ex vivo that does not require cell culturing. Initially, presumed rat PMVECs were isolated from rat peripheral lung tissue using tissue dissociation and enzymatic digestion, and cells were cultured until confluence to assess endothelial marker expression. Anti-CD31, anti-von Willebrand Factor, and anti-α-smooth muscle actin immunocytochemistry/immunofluorescence signal was detected in presumed rat PMVECs, but also in non-endothelial cell type controls. By contrast, flow cytometry using an anti-CD31 antibody and isolectin 1-B4 (from Griffonia simplicifolia) was highly specific for rat PMVECs. We next developed a strategy in which the addition of an immunomagnetic selection step for CD31+ cells permitted culture-free isolation of rat PMVECs ex vivo for RNA isolation and transcriptomic analysis using fluorescence-activated cell sorting. Heterogeneity in the validity and reproducibility of results using commercial antibodies against endothelial surface markers corresponded to a substantial burden on laboratory time, labor, and scientific budget. We demonstrate a novel protocol for the culture-free isolation and transcriptomic analysis of rat PMVECs with translational relevance to PAH. In doing so, we highlight wide variability in the quality of commonly used biological reagents, which emphasizes the importance of investigator-initiated validation of commercial biomaterials.
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Materiales Biocompatibles/farmacología , Separación Celular , Células Endoteliales/metabolismo , Hipertensión Pulmonar/metabolismo , Pulmón/metabolismo , Microvasos/metabolismo , Animales , Antígenos de Diferenciación/biosíntesis , Células Endoteliales/patología , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Hipertensión Pulmonar/patología , Pulmón/irrigación sanguínea , Pulmón/patología , Microvasos/patología , RatasRESUMEN
Germline mutations involving small mothers against decapentaplegic-transforming growth factor-ß (SMAD-TGF-ß) signaling are an important but rare cause of pulmonary arterial hypertension (PAH), which is a disease characterized, in part, by vascular fibrosis and hyperaldosteronism (ALDO). We developed and analyzed a fibrosis protein-protein network (fibrosome) in silico, which predicted that the SMAD3 target neural precursor cell expressed developmentally down-regulated 9 (NEDD9) is a critical ALDO-regulated node underpinning pathogenic vascular fibrosis. Bioinformatics and microscale thermophoresis demonstrated that oxidation of Cys18 in the SMAD3 docking region of NEDD9 impairs SMAD3-NEDD9 protein-protein interactions in vitro. This effect was reproduced by ALDO-induced oxidant stress in cultured human pulmonary artery endothelial cells (HPAECs), resulting in impaired NEDD9 proteolytic degradation, increased NEDD9 complex formation with Nk2 homeobox 5 (NKX2-5), and increased NKX2-5 binding to COL3A1 Up-regulation of NEDD9-dependent collagen III expression corresponded to changes in cell stiffness measured by atomic force microscopy. HPAEC-derived exosomal signaling targeted NEDD9 to increase collagen I/III expression in human pulmonary artery smooth muscle cells, identifying a second endothelial mechanism regulating vascular fibrosis. ALDO-NEDD9 signaling was not affected by treatment with a TGF-ß ligand trap and, thus, was not contingent on TGF-ß signaling. Colocalization of NEDD9 with collagen III in HPAECs was observed in fibrotic pulmonary arterioles from PAH patients. Furthermore, NEDD9 ablation or inhibition prevented fibrotic vascular remodeling and pulmonary hypertension in animal models of PAH in vivo. These data identify a critical TGF-ß-independent posttranslational modification that impairs SMAD3-NEDD9 binding in HPAECs to modulate vascular fibrosis and promote PAH.
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Proteínas Adaptadoras Transductoras de Señales/metabolismo , Colágeno Tipo III/metabolismo , Fibrosis/metabolismo , Fibrosis/patología , Pulmón/metabolismo , Pulmón/patología , Fosfoproteínas/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Animales , Colágeno Tipo III/genética , Células Endoteliales/metabolismo , Células Endoteliales/patología , Femenino , Humanos , Hipertensión Pulmonar/metabolismo , Hipertensión Pulmonar/patología , Hipertensión Pulmonar/fisiopatología , Pulmón/fisiopatología , Masculino , Fosfoproteínas/genética , Unión Proteica , Arteria Pulmonar/patología , Ratas , Ratas Sprague-Dawley , Proteína smad3/genética , Proteína smad3/metabolismo , Biología de Sistemas/métodosRESUMEN
Activation of the mammalian target of rapamycin complex 1 (mTORC1) subunit Raptor induces cell growth and is a downstream target of Akt. Elevated levels of aldosterone activate Akt, and, in pulmonary arterial hypertension (PAH), correlate with pulmonary arteriole thickening, which suggests that mTORC1 regulation by aldosterone may mediate adverse pulmonary vascular remodeling. We hypothesized that aldosterone-Raptor signaling induces abnormal pulmonary artery smooth muscle cell (PASMC) survival patterns to promote PAH. Remodeled pulmonary arterioles from SU-5416/hypoxia-PAH rats and monocrotaline-PAH rats with hyperaldosteronism expressed increased levels of the Raptor target, p70S6K, which provided a basis for investigating aldosterone-Raptor signaling in human PASMCs. Aldosterone (10(-9) to 10(-7) M) increased Akt/mTOR/Raptor to activate p70S6K and increase proliferation, viability, and apoptosis resistance in PASMCs. In PASMCs transfected with Raptor-small interfering RNA or treated with spironolactone/eplerenone, aldosterone or pulmonary arterial plasma from patients with PAH failed to increase p70S6K activation or to induce cell survival in vitro Optimal inhibition of pulmonary arteriole Raptor was achieved by treatment with Staramine-monomethoxy polyethylene glycol that was formulated with Raptor-small interfering RNA plus spironolactone in vivo, which decreased arteriole muscularization and pulmonary hypertension in 2 experimental animal models of PAH in vivo Up-regulation of mTORC1 by aldosterone is a critical pathobiologic mechanism that controls PASMC survival to promote hypertrophic vascular remodeling and PAH.-Aghamohammadzadeh, R., Zhang, Y.-Y., Stephens, T. E., Arons, E., Zaman, P., Polach, K. J., Matar, M., Yung, L.-M., Yu, P. B., Bowman, F. P., Opotowsky, A. R., Waxman, A. B., Loscalzo, J., Leopold, J. A., Maron, B. A. Up-regulation of the mammalian target of rapamycin complex 1 subunit Raptor by aldosterone induces abnormal pulmonary artery smooth muscle cell survival patterns to promote pulmonary arterial hypertension.
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Proteínas Adaptadoras Transductoras de Señales/metabolismo , Aldosterona/farmacología , Regulación de la Expresión Génica/fisiología , Complejos Multiproteicos/metabolismo , Serina-Treonina Quinasas TOR/metabolismo , Regulación hacia Arriba , Proteínas Adaptadoras Transductoras de Señales/genética , Aldosterona/metabolismo , Animales , Apoptosis/fisiología , Proliferación Celular , Supervivencia Celular , Células Cultivadas , Humanos , Hipertensión Pulmonar , Masculino , Diana Mecanicista del Complejo 1 de la Rapamicina , Complejos Multiproteicos/genética , Ratas , Ratas Sprague-Dawley , Proteína Reguladora Asociada a mTOR , Proteínas Quinasas S6 Ribosómicas 70-kDa/genética , Proteínas Quinasas S6 Ribosómicas 70-kDa/metabolismo , Transducción de Señal , Serina-Treonina Quinasas TOR/genéticaRESUMEN
BACKGROUND: The molecular mechanism(s) regulating hypoxia-induced vascular fibrosis are unresolved. Hyperaldosteronism correlates positively with vascular remodeling in pulmonary arterial hypertension, suggesting that aldosterone may contribute to the pulmonary vasculopathy of hypoxia. The hypoxia-sensitive transcription factors c-Fos/c-Jun regulate steroidogenic acute regulatory protein (StAR), which facilitates the rate-limiting step of aldosterone steroidogenesis. We hypothesized that c-Fos/c-Jun upregulation by hypoxia activates StAR-dependent aldosterone synthesis in human pulmonary artery endothelial cells (HPAECs) to promote vascular fibrosis in pulmonary arterial hypertension. METHODS AND RESULTS: Patients with pulmonary arterial hypertension, rats with Sugen/hypoxia-pulmonary arterial hypertension, and mice exposed to chronic hypoxia expressed increased StAR in remodeled pulmonary arterioles, providing a basis for investigating hypoxia-StAR signaling in HPAECs. Hypoxia (2.0% FiO2) increased aldosterone levels selectively in HPAECs, which was confirmed by liquid chromatography-mass spectrometry. Increased aldosterone by hypoxia resulted from enhanced c-Fos/c-Jun binding to the proximal activator protein-1 site of the StAR promoter in HPAECs, which increased StAR expression and activity. In HPAECs transfected with StAR-small interfering RNA or treated with the activator protein-1 inhibitor SR-11302 [3-methyl-7-(4-methylphenyl)-9-(2,6,6-trimethylcyclohexen-1-yl)nona-2,4,6,8-tetraenoic acid], hypoxia failed to increase aldosterone, confirming that aldosterone biosynthesis required StAR activation by c-Fos/c-Jun. The functional consequences of aldosterone were confirmed by pharmacological inhibition of the mineralocorticoid receptor with spironolactone or eplerenone, which attenuated hypoxia-induced upregulation of the fibrogenic protein connective tissue growth factor and collagen III in vitro and decreased pulmonary vascular fibrosis to improve pulmonary hypertension in vivo. CONCLUSION: Our findings identify autonomous aldosterone synthesis in HPAECs attributable to hypoxia-mediated upregulation of StAR as a novel molecular mechanism that promotes pulmonary vascular remodeling and fibrosis.
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Aldosterona/biosíntesis , Células Endoteliales/metabolismo , Hipoxia/metabolismo , Fosfoproteínas/biosíntesis , Arteria Pulmonar/metabolismo , Fibrosis Pulmonar/metabolismo , Regulación hacia Arriba/fisiología , Animales , Células Cultivadas , Humanos , Hipoxia/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Arteria Pulmonar/citología , Arteria Pulmonar/patología , Fibrosis Pulmonar/patología , Distribución Aleatoria , Ratas , Ratas Sprague-DawleyRESUMEN
Pulmonary hypertension (PH) is characterized by pulmonary arteriolar remodeling with excessive pulmonary vascular smooth muscle cell (VSMC) proliferation. This results in decreased responsiveness of pulmonary circulation to vasodilator therapies. We have shown that extracellular acidosis inhibits VSMC proliferation and migration in vitro. Here we tested whether induction of nonhypercapnic acidosis in vivo ameliorates PH and the underlying pulmonary vascular remodeling and dysfunction. Adult male Sprague-Dawley rats were exposed to hypoxia (8.5% O(2)) for 2 wk, or injected subcutaneously with monocrotaline (MCT, 60 mg/kg) to develop PH. Acidosis was induced with NH(4)Cl (1.5%) in the drinking water 5 days prior to and during the 2 wk of hypoxic exposure (prevention protocol), or after MCT injection from day 21 to 28 (reversal protocol). Right ventricular systolic pressure (RVSP) and Fulton's index were measured, and pulmonary arteriolar remodeling was analyzed. Pulmonary and mesenteric artery contraction to phenylephrine (Phe) and high KCl, and relaxation to acetylcholine (ACh) and sodium nitroprusside (SNP) were examined ex vivo. Hypoxic and MCT-treated rats demonstrated increased RVSP, Fulton's index, and pulmonary arteriolar thickening. In pulmonary arteries of hypoxic and MCT rats there was reduced contraction to Phe and KCl and reduced vasodilation to ACh and SNP. Acidosis prevented hypoxia-induced PH, reversed MCT-induced PH, and resulted in reduction in all indexes of PH including RVSP, Fulton's index, and pulmonary arteriolar remodeling. Pulmonary artery contraction to Phe and KCl was preserved or improved, and relaxation to ACh and SNP was enhanced in NH(4)Cl-treated PH animals. Acidosis alone did not affect the hemodynamics or pulmonary vascular function. Phe and KCl contraction and ACh and SNP relaxation were not different in mesenteric arteries of all groups. Thus nonhypercapnic acidosis ameliorates experimental PH, attenuates pulmonary arteriolar thickening, and enhances pulmonary vascular responsiveness to vasoconstrictor and vasodilator stimuli. Together with our finding that acidosis decreases VSMC proliferation, the results are consistent with the possibility that nonhypercapnic acidosis promotes differentiation of pulmonary VSMCs to a more contractile phenotype, which may enhance the effectiveness of vasodilator therapies in PH.
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Acidosis Respiratoria/fisiopatología , Remodelación de las Vías Aéreas (Respiratorias) , Hipertensión Pulmonar/fisiopatología , Hipoxia/fisiopatología , Pulmón/irrigación sanguínea , Acetilcolina/farmacología , Acidosis Respiratoria/inducido químicamente , Cloruro de Amonio , Animales , Antihipertensivos/farmacología , Presión Sanguínea , Dióxido de Carbono/sangre , Agonistas Colinérgicos/farmacología , Ventrículos Cardíacos/patología , Ventrículos Cardíacos/fisiopatología , Hipertensión Pulmonar/inducido químicamente , Hipertrofia , Técnicas In Vitro , Pulmón/patología , Pulmón/fisiopatología , Masculino , Monocrotalina , Nitroprusiato/farmacología , Tamaño de los Órganos , Fenilefrina/farmacología , Arteria Pulmonar/efectos de los fármacos , Arteria Pulmonar/fisiopatología , Ratas , Ratas Sprague-Dawley , Transducción de Señal/efectos de los fármacos , Vasoconstricción/efectos de los fármacos , Vasoconstrictores/farmacologíaRESUMEN
BACKGROUND: Unbalanced vascular smooth muscle cell (VSMC) proliferation, migration, and apoptosis contribute to vascular disorders such as atherosclerosis, restenosis, and pulmonary hypertension. The effect of extracellular acidosis (EA) on VSMC homeostasis is incompletely understood but we previously reported that EA increases heme oxygenase-1 (HO-1) expression in VSMCs. Since HO-1 regulates VSMC proliferation and apoptosis we sought to define the role of HO-1 in VSMC responses to EA. METHODS: Mouse aortic smooth muscle cells (MASMCs) were isolated from wild-type and HO-1-null mice. Cell proliferation and migration assays were done in a physiologic pH (7.4) or EA (pH 6.8). VSMC apoptosis in response to hydrogen peroxide was assessed by JC-1 staining, caspase-3 cleavage, annexin V, and Hoechst staining. RESULTS: Wild-type MASMCs showed decreased proliferation and migration at pH 6.8 compared to pH 7.4. This observation was also true in HO-1-null MASMCs. Although wild-type and HO-1-null cells showed differences in the mode and kinetics of cell death, both genotypes exhibited increased susceptibility to hydrogen peroxide-induced apoptosis at pH 6.8 compared to 7.4. CONCLUSIONS: EA inhibits VSMC proliferation and migration and increases susceptibility to oxidant-induced apoptosis. These effects of acidosis on VSMC homeostasis are independent of HO-1.
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Acidosis/patología , Apoptosis , Proliferación Celular , Hemo-Oxigenasa 1/fisiología , Proteínas de la Membrana/fisiología , Músculo Liso Vascular/citología , Miocitos del Músculo Liso/fisiología , Acidosis/enzimología , Animales , Movimiento Celular , Células Cultivadas , Peróxido de Hidrógeno/toxicidad , RatonesRESUMEN
STUDY OBJECTIVES: To evaluate the effect of body position on REM-related obstructive sleep apnea (OSA) patients. DESIGN: Retrospective analysis. PATIENTS: 100 consecutive adult OSA patients (apnea-hypopnea index [AHI] > or = 5) who had > or = 10 min of REM sleep in both supine and lateral postures. REM-related OSA was defined by previously used criteria (REM AHI/Non-REM (NREM) AHI > or = 2) and was compared with data from Not-REM-related OSA (REM AHI/NREM AHI < 2). MEASUREMENTS AND RESULTS: Most (93%) of the REM-related OSA patients (n = 45) had a mild-moderate syndrome, compared to 50.9% in the Not-REM-related OSA patients (n = 55). REM-related OSA patients had a lower apnea index (AL), AHI, supine and lateral AHI, and NREM AHI, but similar REM AHI compared to the Not-REM-related OSA group. For the entire group, the following sequence was observed: AHI REM supine > AHI NREM supine > AHI REM lateral > AHI NREM lateral. Also, for the REM-related and Not-REM-related OSA patients, the interaction between supine posture and REM sleep led to the highest AHI. However, the average length of apnea and hypopneas during REM sleep was similar in the supine and lateral postures. CONCLUSIONS: During REM sleep, the supine position is associated with increased frequency but not increased duration of apneas and hypopneas. These body position effects prevail over the differences between REM-related and Not-REM-related OSA patients.
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Polisomnografía , Postura , Apnea Obstructiva del Sueño/diagnóstico , Fases del Sueño , Sueño REM , Posición Supina , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo , Apnea Obstructiva del Sueño/etiologíaRESUMEN
Pulmonary hypertension (PH) is a life-threatening disease with unclear vascular mechanisms. We tested whether PH involves abnormal pulmonary vasoconstriction and impaired vasodilation. Male Sprague-Dawley rats were exposed to hypoxia (9% O(2)) for 2 weeks or injected with single dose of monocrotaline (MCT, 60 mg/kg s.c.). Control rats were normoxic or injected with saline. After the hemodynamic measurements were performed, pulmonary and mesenteric arteries were isolated for measurement of vascular function. Hematocrit was elevated in hypoxic rats. Right ventricular systolic pressure and Fulton's Index [right/(left + septum) ventricular weight] were greater in hypoxic and MCT-treated rats than in normoxic rats. Pulmonary artery contraction by phenylephrine and 96 mM KCl was less in hypoxic and MCT-treated rats than in normoxic rats. Acetylcholine-induced relaxation was less in the pulmonary arteries of hypoxic and MCT-treated rats than of normoxic rats, suggesting reduced effects of endothelium-derived vasodilators. The nitric oxide synthase inhibitor, N(omega)-nitro-l-arginine methyl ester, and the guanylate cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, inhibited acetylcholine relaxation, suggesting that it was mediated by nitric oxide (NO)-cGMP. The NO donor sodium nitroprusside caused less relaxation in the pulmonary arteries of hypoxic and MCT-treated than of normoxic rats, suggesting decreased responsiveness of vascular smooth muscle cells (VSMCs) to vasodilators. Phenylephrine and KCl contraction and acetylcholine and sodium nitroprusside relaxation were not different in the mesenteric arteries from all groups. In lung tissue sections, the wall thickness of pulmonary arterioles was greater in hypoxic and MCT-treated rats than in normoxic rats. The specific reductions in pulmonary, but not systemic, arterial vasoconstriction and vasodilation in hypoxia- and MCT-induced PH are consistent with the possibility of de-differentiation of pulmonary VSMCs to a more proliferative/synthetic and less contractile phenotype in PH.
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Hipertensión Pulmonar/fisiopatología , Óxido Nítrico/fisiología , Arteria Pulmonar/fisiopatología , Vasoconstricción/fisiología , Vasodilatación/fisiología , Animales , Modelos Animales de Enfermedad , Hipertensión Pulmonar/inducido químicamente , Hipertensión Pulmonar/patología , Hipoxia/fisiopatología , Pulmón/patología , Masculino , Arterias Mesentéricas/efectos de los fármacos , Arterias Mesentéricas/fisiopatología , Monocrotalina , Miocardio/patología , Arteria Pulmonar/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Vasoconstricción/efectos de los fármacos , Vasoconstrictores/farmacología , Vasodilatación/efectos de los fármacos , Vasodilatadores/farmacologíaRESUMEN
OBJECTIVES/HYPOTHESIS: To compare demographic and polysomnographic data of sleepy versus nonsleepy severe obstructive sleep apnea (OSA) patients according to the Epworth Sleepiness Scale (ESS). STUDY DESIGN: Retrospective cohort. METHODS: Six hundred forty-four consecutive severe (apnea-hypopnea index [AHI] >or= 30) adult OSA patients who underwent a polysomnographic evaluation in our sleep disorders unit. ESS data were available in 569 (88.3%). Three hundred twenty-seven (57.5%) patients had ESS > 10. RESULTS: Sleepy severe OSA patients are slightly younger and more obese than nonsleepy patients. These sleepy patients have shorter sleep latency and lower percentage of slow wave sleep. They consistently show a higher AHI, both supine and lateral AHI, have a higher number of short arousals, and a higher arousal index. They also have higher snoring loudness in the supine and both lateral positions and a lower minimal SaO(2) in rapid eye movement and non-rapid eye movement sleep. After adjusting for confounders, a logistic regression model points to apnea index as a significant prognostic factor for excessive daytime sleepiness. CONCLUSIONS: Severe OSA sleepy patients have a syndrome that is significantly more severe than nonsleepy patients. Sleepy patients have worse sleep-related breathing parameters, and their sleep patterns are lighter and more fragmented than nonsleepy patients. Apnea index appears as an important prognostic factor for excessive daytime sleepiness.
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Apnea Obstructiva del Sueño/fisiopatología , Sueño/fisiología , Factores de Edad , Distribución de Chi-Cuadrado , Demografía , Femenino , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Obesidad/complicaciones , Polisomnografía , Pronóstico , Curva ROC , Estudios Retrospectivos , Factores de Riesgo , Fases del Sueño/fisiología , Sueño REM/fisiologíaRESUMEN
The aim of this study was to evaluate demographic and polysomnographic characteristics of positional (PPJ) and non-positional obstructive (NPP) sleep apnea (OSA) patients in 2077 OSA patients diagnosed in our Sleep Disorders Unit during a period of 10 years. An OSA patient is defined as positional if he has twice as many or more breathing abnormalities (apnea and hypopneas) while he sleeps in his supine posture compared to the lateral ones. Of the 2077 OSA patients, 1118 (53.8%) were positional and 959 (46.2%) were non-positional. No age differences were found between these two groups of patients. However, NPP were heavier and thus had a higher BMI than PP. PP had fewer and Less severe breathing abnormalities during sleep compared to NPP and thus, they enjoyed better sleep quality expressed by higher percentages of stage 2, 4 and 3+4 as well as a lower amount of short arousals than NPP. Also, PP patients are less sleepy during daytime hours than NPP. During the Multiple Sleep Latency Test (MSLT), NPP fall asleep faster in every nap than PP patients. No differences between these two patient groups were found for any parameter of Periodic Limb Movement Disorders. AHI and BMI are independently but inversely related to positional dependency. As AHI and BMI increase, the Likelihood to be a positional patient decreases. NPP have breathing abnormalities in the supine and lateral postures, thus, for them without question, CPAP is the treatment of choice. Since avoiding the supine posture during sleep may significantly improve the sleep quality and daytime alertness of many positional patients, it is imperative to carry out a high-quality study to evaluate if this is a real therapeutic alternative for many positional patients.
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Fenómenos Fisiológicos Respiratorios , Apnea Obstructiva del Sueño/fisiopatología , Sueño/fisiología , Posición Supina/fisiología , Adulto , Nivel de Alerta , Índice de Masa Corporal , Humanos , Persona de Mediana Edad , Postura/fisiología , Índice de Severidad de la Enfermedad , Síndromes de la Apnea del Sueño/fisiopatología , Sueño REMRESUMEN
Extracellular acidosis (EA) regulates Heme Oxygenase-1 (HO-1) expression in vascular smooth muscle cells via transcriptional and posttranscriptional mechanisms but the signaling pathways involved are not known. We examined the role of Mitogen-Activated Protein Kinase (MAPK) pathways in HO-1 regulation by EA. Primary rat aortic smooth muscle cells were exposed to EA or physiologic pH. Levels of the total and phosphorylated forms of p38, extracellular signal-regulated protein kinases1/2 (ERK1/2), c-Jun N-terminal kinases/stress-activated protein kinases (JNK1/2), and HO-1 protein were assessed by Western analysis and HO-1 mRNA levels were assessed by quantitative PCR. Inhibition of p38 MAPK was achieved with the chemical inhibitor SB203580, or adenoviral infection of a dominant-negative form of p38alpha. Phospho p38 MAPK activity was evaluated with an in vitro kinase activity assay. Binding of Activator Protein-1 (AP-1), a known target of MAPK pathways, was assessed by Electromobility shift assay (EMSA). EA induced phosphorylation of p38 MAPK in a biphasic manner while total p38 was unchanged. EA did not alter levels of phospho ERK 1/2 and phospho JNK 1/2. There was increased phospho p38 MAPK activity in the setting of EA which preceded the induction of HO-1. Inhibition of phospho p38 activity with either SB20358 or a dominant negative p38alpha oligonucleotide abrogated the induction of HO-1 by EA. Increased specific binding of AP-1 in the setting of EA was shown by EMSA. Increased phospho p38 activity precedes and likely mediates HO-1 induction by EA. Increased AP-1 binding may underlie the transcriptional regulation of HO-1 by EA.
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Hemo-Oxigenasa 1/metabolismo , Sistema de Señalización de MAP Quinasas/fisiología , Músculo Liso Vascular/enzimología , Miocitos del Músculo Liso/enzimología , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Animales , Aorta/citología , Sitios de Unión , Movimiento Celular , Proliferación Celular , Concentración de Iones de Hidrógeno , Imidazoles/farmacología , Músculo Liso Vascular/citología , Piridinas/farmacología , Ratas , Factor de Transcripción AP-1/metabolismoRESUMEN
OBJECTIVE: The aim of this study was to validate a small electronic electromyographic device (BiteStrip) designed to screen masseter electromyographic events that indicate sleep bruxism (SB) against traditional masseter electromyographic events (MEMG). STUDY DESIGN: Six SB treatment-seeking patients, 4 obstructive sleep apnea (OSA) patients and 8 symptom-free controls, underwent overnight polysomnography, including MEMG and BiteStrip recordings. Total BiteStrip and MEMG scores and indices (events per hour) based on total recording time (TRT) and total sleep time (TST) were computed. Measures of accuracy, Spearman's rho correlations, and nonparametric group comparisons were performed. RESULTS: BiteStrip average sensitivity was 0.72, average positive predictive value was 0.75. Correlations between left BiteStrip and MEMG total scores, TRT, and TST indices were r = 0.81, r = 0.79, and r = 0.79, respectively. Bland-Altman plots showed good agreement between indices. Significant group differences were observed for total scores and indices. CONCLUSIONS: BiteStrip and MEMG scores showed strong relationships. Sensitivity and positive predictive value were acceptable. The BiteStrip is a viable screener for identifying masseter electromyographic events that indicate SB.
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Electromiografía/instrumentación , Músculo Masetero/fisiopatología , Bruxismo del Sueño/diagnóstico , Adulto , Métodos Epidemiológicos , Femenino , Humanos , Masculino , Polisomnografía/instrumentación , Apnea Obstructiva del Sueño/diagnósticoRESUMEN
BACKGROUND: Approximately half of obstructive sleep apnea (OSA) patients are positional (i.e., the majority of their breathing abnormalities during sleep appear in the supine posture). Little information exists as to whether avoiding the supine posture during sleep (positional therapy) is a valuable form of therapy for these patients. AIM: To assess the use of positional therapy (by the tennis ball technique [TBT]) during a 6 month period in 78 consecutive positional OSA patients. METHODS: Demographic, polysomnographic, and self-reported questionnaire data on the use of the TBT were analyzed. RESULTS: Of the 50 patients who returned the questionnaire, 19 (38%) (group A) said they were still using the TBT, and 12 (24%) (group B) said they used it initially and stopped using it within a few months but were still avoiding the supine position during sleep. Nineteen patients (38%) (group C) stopped using the TBT within a few months but did not learn how to avoid the sleep supine posture. Patients still using the TBT showed a significant improvement in their self-reported sleep quality (P < .005) and daytime alertness (P < .046) and a decrease in snoring loudness (P < .001). Patients of groups A and B were older than patients who did not comply with this therapy (P < .001). The main reason for patients stopping the use of the TBT in group C was that using it was uncomfortable. CONCLUSIONS: Positional therapy appears to be a valuable form of therapy mainly for some older aged positional OSA patients.
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Postura , Apnea Obstructiva del Sueño/terapia , Anciano , Atención , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Proyectos Piloto , Resultado del TratamientoRESUMEN
STUDY OBJECTIVES: To investigate polysomnographic and anthropomorphic factors predicting need of high optimal continuous positive airway pressure (CPAP). DESIGN: Retrospective data analysis. PATIENTS: Three hundred fifty-three consecutive obstructive sleep apnea (OSA) patients who had a successful manual CPAP titration in our sleep disorders unit. MEASUREMENTS AND RESULTS: The mean optimal CPAP was 9.5 +/- 2.4 cm H2O. The optimal CPAP pressure increases with an increase in OSA severity from 7.79 +/- 2.2 in the mild, to 8.7 +/- 1.8 in the moderate, and to 10.1 +/- 2.3 cm H2O in the severe OSA group. A high CPAP was defined as the mean + 1 standard deviation (SD; > or =12 cm H2O). The predictor variables included apnea-hypopnea index (AHI), age, sex, body mass index (BMI), Epworth Sleepiness Scale (ESS), and the Multiple Sleep Latency Test (MSLT). High CPAP was required in 2 (6.9%), 6 (5.8%), and 63 (28.6%) patients with mild, moderate, and severe OSA, respectively. On univariate analysis, AHI, BMI, ESS score, and the proportion of males were significantly higher in those needing high CPAP. They also have a lower MSLT mean. On logistic regression, the use of high CPAP was 5.90 times more frequent (95% confidence interval 2.67-13.1) in severe OSA patients after adjustment for the other variables. The area under the receiver operator curve was 72.4%, showing that the model was adequate. CONCLUSIONS: Severe OSA patients are much more likely to need high CPAP levels. However, because of the low positive predictive value (only 28.6%), the clinical value of such information is limited. ESS and MSLT did not increase the predictive value for the need for high CPAP.