NEDD9 Is a Novel and Modifiable Mediator of Platelet-Endothelial Adhesion in the Pulmonary Circulation.

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.

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.

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.

Upregulation of steroidogenic acute regulatory protein by hypoxia stimulates aldosterone synthesis in pulmonary artery endothelial cells to promote pulmonary vascular fibrosis.

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.

Branched chain α-ketoacids aerobically activate HIF1α signaling in vascular cells.

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.

Evidence of Advanced Pulmonary Vascular Remodeling in Obstructive Hypertrophic Cardiomyopathy With Pulmonary Hypertension.

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.

Improved pulmonary vascular reactivity and decreased hypertrophic remodeling during nonhypercapnic acidosis in experimental pulmonary hypertension.

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.

Heme oxygenase-1 does not mediate the effects of extracellular acidosis on vascular smooth muscle cell proliferation, migration, and susceptibility to apoptosis.

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.

Individualized interactomes for network-based precision medicine in hypertrophic cardiomyopathy with implications for other clinical pathophenotypes.

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.

Impaired vasoconstriction and nitric oxide-mediated relaxation in pulmonary arteries of hypoxia- and monocrotaline-induced pulmonary hypertensive rats.

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.

[The significance of body posture on breathing abnormalities during sleep: data analysis of 2077 obstructive sleep apnea patients].

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.

Isolating pulmonary microvascular endothelial cells ex vivo: Implications for pulmonary arterial hypertension, and a caution on the use of commercial biomaterials.

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.

The p38 mitogen-activated protein kinase pathway is involved in the regulation of heme oxygenase-1 by acidic extracellular pH in aortic smooth muscle cells.

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.

NEDD9 targets COL3A1 to promote endothelial fibrosis and pulmonary arterial hypertension.

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.

Does the severity of obstructive sleep apnea predict patients requiring high continuous positive airway pressure?

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.

Positional therapy for obstructive sleep apnea patients: A 6-month follow-up study.

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.

Sleep bruxism related to obstructive sleep apnea: the effect of continuous positive airway pressure.

Several studies have reported that sleep bruxism rarely occurs in isolation. Recently, in an epidemiological study of sleep bruxism and risk factors in the general population, it was found that among the associated sleep symptoms and disorders obstructive sleep apnea (OSA) was the highest risk factor for tooth grinding during sleep. The purpose of this report was to evaluate the effect of continuous positive airway pressure (CPAP) on sleep bruxism in a patient with both severe OSA and sleep tooth grinding. Two polysomnographic (PSG) recordings were carried out. The first showed 67 events of sounded tooth grinding, most of them appearing as an arousal response at the end of apnea/hypopnea events in both the supine and lateral postures. During the CPAP titration night most breathing abnormalities were eliminated and a complete eradication of the tooth grinding events was observed. The results of this study suggest that when sleep bruxism is related to apnea/hypopneas, the successful treatment of these breathing abnormalities may eliminate bruxism during sleep.

Rapid Eye Movement (REM) sleep behavior disorder: a sleep disturbance affecting mainly older men.

Rapid Eye Movement (REM) sleep behavior disorder is characterized by the intermittent loss of REM-related muscle atonia and the appearance of elaborated motor behaviors (sometimes violent behavior) and vocalizations associated with dream mentation. Nine patients were diagnosed in our Sleep Disorders Unit with this syndrome during the period August 1997-April 2000. All were male, average age 67.9 +/- 6.9 years. The complaint of all our patients was the occurrence of violent or injurious sleep behavior mainly during the dream stage. Jumping or falling out of bed and slapping or beating their wives were more common. None had history or showed signs of dementia, Parkinson or other neurodegenerative diseases. A relative high amount of SWS (20.9%) was found. Seven showed an intermittent increase in chin EMG tonus while the other two had an almost continuous high chin EMG tonus during REM sleep. We did not observe any violent motor behavior during the polysomnographic recordings. Phasic activities during REM sleep were high but density quantification was not performed. Six patients had also Periodic Limb Movement (PLM) Disorders, four had also Obstructive Sleep Apnea (OSA) Syndrome. The treatment recommended to all patients was Clonazepam beginning with a 0.5-mg dose. Four patients reported a decrease or disappearance of sleep agitation and nightmares and were very happy with the treatment and without side effects. The others decided not to try Clonazepam or stopped after a few days of using it. RBD appears to be a sleep disturbance affecting mainly aged men. Its violent expression may frighten the patients and their bed-partners and may cause injury to both. In some cases this sleep disorder seems to be an early manifestation of a neurodegenerative disorder while in others it may represent only an idiopathic form. Clonazepam at lower doses is a good agent for the treatment of this condition.

REM-related obstructive sleep apnea: the effect of body position.

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.