endothelin-1 and Sleep-Apnea-Syndromes

We investigated the effect of intermittent hypoxia, mimicking sleep apnea, on axonal integrity, blood-brain barrier permeability, and cognitive function of mice. Forty-seven C57BL mice were exposed to intermittent or sham hypoxia, alternating 30s of progressive hypoxia and 30s of reoxigenation, during 8h/day. The axonal integrity in cerebellum was evaluated by transmission electron microscopy. Short- and long-term memories were assessed by novel object recognition test. The levels of endothelin-1 were measured by ELISA. Blood-brain barrier permeability was quantified by Evans Blue dye. After 14 days, animals exposed to intermittent hypoxia showed hypomyelination in cerebellum white matter and higher serum levels of endothelin-1. The short and long-term memories in novel object recognition test was impaired in the group exposed to intermittent hypoxia as compared to controls. Blood-brain barrier permeability was similar between the groups. These results indicated that hypomyelination and impairment of short- and long-term working memories occurred in C57BL mice after 14 days of intermittent hypoxia mimicking sleep apnea.

Topics: Animals; Axons; Blood-Brain Barrier; Capillary Permeability; Cerebellum; Cerebrum; Disease Models, Animal; Endothelin-1; Enzyme-Linked Immunosorbent Assay; Evans Blue; Hypoxia; Male; Memory Disorders; Memory, Short-Term; Mice, Inbred C57BL; Myelin Sheath; Neuropsychological Tests; Recognition, Psychology; Sleep Apnea Syndromes; White Matter

Sleep apnea (SA), defined as intermittent respiratory arrest during sleep, is associated with increased incidence of hypertension, peripheral vascular disease, stroke, and sudden cardiac death. We have shown that intermittent hypoxia with CO2 supplementation (IH), a model for SA, increases blood pressure and circulating ET-1 levels, upregulates lung pre-pro ET-1 mRNA, increases vasoconstrictor reactivity to ET-1 in rat small mesenteric arteries (MA) and increases vascular reactive oxygen species (ROS). NFAT activity is increased in the aorta (AO) and MA of mice exposed to IH in an ET-1-dependent manner, and the genetic ablation of the isoform NFATc3 prevents IH-induced hypertension. We hypothesized that IH causes an increase in arterial ROS generation, which activates NFATc3 to increase vasoconstrictor reactivity to ET-1. In support of our hypothesis, we found that IH increases ROS in AO and MA. In vivo administration of the SOD mimetic tempol during IH exposure prevents IH-induced increases in NFAT activity in mouse MA and AO. We found that IH causes an NFATc3-dependent increase in vasoconstrictor reactivity to ET-1, accompanied by an increase in vessel wall [Ca²⁺]. Our results indicate that IH exposure causes an increase in arterial ROS to activate NFATc3, which then increases vasoconstrictor reactivity and Ca²⁺ response to ET-1. These studies highlight a novel regulatory pathway, and demonstrate the potential clinical relevance of NFAT inhibition to prevent hypertension in SA patients.

Topics: Animals; Calcium; Endothelin-1; Female; Hypoxia; Kv1.5 Potassium Channel; Male; Mice; Mice, Inbred BALB C; NFATC Transcription Factors; Protein Carbonylation; Rats; Reactive Oxygen Species; Sleep Apnea Syndromes; TRPC Cation Channels; TRPC6 Cation Channel; Vasoconstriction

Obstructive sleep apnea (OSA) is associated with cardiovascular complications including hypertension. Previous findings from our laboratory indicate that exposure to intermittent hypoxia (IH), to mimic sleep apnea, increases blood pressure in rats. IH also increases endothelin-1 (ET-1) constrictor sensitivity in a protein kinase C (PKC) δ-dependent manner in mesenteric arteries. Because phosphoinositide-dependent kinase-1 (PDK-1) regulates PKCδ activity, we hypothesized that PDK-1 contributes to the augmented ET-1 constrictor sensitivity and elevated blood pressure following IH. Male Sprague-Dawley rats were exposed to either sham or IH (cycles between 21% O(2)/0% CO(2) and 5% O(2)/5% CO(2)) conditions for 7 h/day for 14 or 21 days. The contribution of PKCδ and PDK-1 to ET-1-mediated vasoconstriction was assessed in mesenteric arteries using pharmacological inhibitors. Constrictor sensitivity to ET-1 was enhanced in arteries from IH-exposed rats. Inhibition of PKCδ or PDK-1 blunted ET-1 constriction in arteries from IH but not sham group rats. Western analysis revealed similar levels of total and phosphorylated PDK-1 in arteries from sham and IH group rats but decreased protein-protein interaction between PKCδ and PDK-1 in arteries from IH- compared with sham-exposed rats. Blood pressure was increased in rats exposed to IH, and treatment with the PDK-1 inhibitor OSU-03012 [2-amino-N-{4-[5-(2-phenanthrenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]-phenyl}-acetamide] (33 mg/day) lowered blood pressure in IH but not sham group rats. Our results suggest that exposure to IH unmasks a role for PDK-1 in regulating ET-1 constrictor sensitivity and blood pressure that is not present under normal conditions. These novel findings suggest that PDK-1 may be a uniquely effective antihypertensive therapy for OSA patients.

Topics: 3-Phosphoinositide-Dependent Protein Kinases; Animals; Blood Pressure; Endothelin-1; Enzyme Inhibitors; Hypoxia; Immunoprecipitation; Male; Mesenteric Arteries; Phosphorylation; Protein Kinase C-delta; Protein Serine-Threonine Kinases; Pyrazoles; Rats; Rats, Sprague-Dawley; Sleep Apnea Syndromes; Sulfonamides; Vasoconstriction

Post-traumatic stress disorder (PTSD) is gaining increasing recognition as a risk factor for morbidity and mortality. The aim of this study was to examine the impact of PTSD and abnormal cardiovascular biomarkers on mortality in military veterans. Eight hundred ninety-one patients presenting for routine echocardiography were enrolled. Baseline clinical data and serum samples for biomarker measurement were obtained and echocardiography was performed at the time of enrollment. Patients were followed for up to 7.5 years for the end point of all-cause mortality. Ninety-one patients had PTSD at the time of enrollment. There were 33 deaths in patients with PTSD and 221 deaths in those without PTSD. Patients with PTSD had a trend toward worse survival on Kaplan-Meier analysis (p = 0.057). Among patients with elevated B-type natriuretic peptide (>60 pg/ml), those with PTSD had significantly increased mortality (p = 0.024). Among patients with PTSD, midregional proadrenomedullin (MR-proADM), creatinine, and C-terminal proendothelin-1 were significant univariate predictors of mortality (p = 0.006, p = 0.024, and p = 0.003, respectively). In a multivariate model, PTSD, B-type natriuretic peptide, and MR-proADM were independent predictors of mortality. In patients with PTSD, MR-proADM was a significant independent predictor of mortality after adjusting for B-type natriuretic peptide, cardiovascular risk factors, cancer, and sleep apnea. Adding MR-proADM to clinical predictors of mortality increased the C-statistic from 0.572 to 0.697 (p = 0.007). In conclusion, this study demonstrates an association among PTSD, abnormal cardiac biomarker levels, and increased mortality.

Topics: Adrenomedullin; Aged; Biomarkers; Creatinine; Echocardiography; Endothelin-1; Female; Follow-Up Studies; Humans; Kaplan-Meier Estimate; Male; Multivariate Analysis; Natriuretic Peptide, Brain; Peptide Fragments; Protein Precursors; Sleep Apnea Syndromes; Stress Disorders, Post-Traumatic; United States; Veterans

This study aimed to evaluate the influence of adenotonsillectomy on the plasma concentration of endothelin-1 (ET-1) and C-reactive protein (CRP) in children with sleep-disordered breathing (SDB). The relationship between quality of life and ET-1 levels was also evaluated.. Tertiary referral center.. Before-and-after case series.. Fasting blood samples for ET-1 and high-sensitivity CRP were drawn preoperatively in all patients and at 3 to 4 months postoperatively. The Obstructive Sleep Apnea-18 (OSA-18) survey and Brouilette symptom score were completed by each child's parents during the same time periods.. The mean ET-1 level decreased from 3.51 ± 0.93 fmol/mL to 2.67 ± 0.69 fmol/mL postoperatively (P < .01). OSA-18 survey scores and Brouilette symptom scores also decreased in the postoperative period (P < .01). When comparing moderate and severe cases to mild cases according to Brouilette scores, ET-1 levels were significantly higher in moderate and severe cases (P < .01). There was a significant correlation between ET-1 and the OSA-18 survey scale (r = 0.442; P = .001). Although CRP levels decreased from 0.63 ± 1.19 mg/dL to 0.31 ± 0.23 mg/dL postoperatively, this was not statistically significant.. Adenotonsillectomy effectively lowered plasma ET-1 levels in children with SDB and thus may have reduced their related risk for cardiovascular disease. In addition, adenotonsillectomy improved quality of life in this group.

Topics: Adenoidectomy; Adolescent; Biomarkers; C-Reactive Protein; Child; Child, Preschool; Cohort Studies; Endothelin-1; Female; Follow-Up Studies; Humans; Male; Polysomnography; Postoperative Care; Preoperative Care; Quality of Life; Severity of Illness Index; Sleep Apnea Syndromes; Statistics, Nonparametric; Tonsillectomy; Treatment Outcome

The HIF-1alpha expression in the carotid body (CB) is central to the transcriptional regulation of the CB structural and functional changes in chronic hypoxia (CH). The CB plays pathogenic roles in cardiovascular morbidity in patients with sleep-disordered breathing; yet, the expression and role of HIF-alpha subtypes in intermittent hypoxia (IH), resembling recurrent episodic apnea, are unclear. We hypothesized a divergent role of HIF-alpha subtypes, regulated by differential expression in the CB response to IH. A time-course analysis of the CB volume, and expression profiles of the HIF-1alpha, -2alpha, -3alpha and HIF-regulated gene products, including vascular endothelial growth factor (VEGF), endothelin-1 (ET-1), and tyrosine hydroxylase (TH), showed a significant difference in the lack of increase in the rat CB volume, HIF-1alpha and VEGF expression during IH, despite an increase in the mRNA level of HIF-1alpha and the prominent increase of volume and expression in the CH group. In contrast, there were increased CB expressions of HIF-2alpha and -3alpha, and also ET-1 and TH in both IH and CH groups. Results demonstrated a significant role played by HIF-2alpha and -3alpha in the CB response to IH, which could be complementary to the expression and role of HIF-1alpha under hypoxic conditions. This differential regulation of the HIF-alpha subtypes and pathways could account for the morphological and neurochemical discrepancy in the CB responses to IH and CH.

Topics: Animals; Basic Helix-Loop-Helix Transcription Factors; Carotid Body; Chemoreceptor Cells; Disease Models, Animal; Endothelin-1; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Male; Random Allocation; Rats; Rats, Sprague-Dawley; RNA, Messenger; Sleep Apnea Syndromes; Time Factors; Transcription Factors; Tyrosine 3-Monooxygenase; Vascular Endothelial Growth Factor A

Sleep apnea, defined as intermittent respiratory arrest during sleep, is associated with increased incidence of hypertension and peripheral vascular disease. Exposure of rodents to brief periods of intermittent hypercarbia/hypoxia (H-IH) during sleep mimics the cyclical hypoxia-normoxia of sleep apnea. Endothelin-1, an upstream activator of nuclear factor of activated T cells (NFAT), is increased during H-IH. Therefore, we hypothesized that NFATc3 is activated by H-IH and is required for H-IH-induced hypertension. Consistent with this hypothesis, we found that H-IH (20 brief exposures per hour to 5% O(2)-5% CO(2) for 7 h/day) induces systemic hypertension in mice [mean arterial pressure (MAP) = 97 +/- 2 vs. 124 +/- 2 mmHg, P < 0.05, n = 5] and increases NFATc3 transcriptional activity in aorta and mesenteric arteries. Cyclosporin A, an NFAT inhibitor, and genetic ablation of NFATc3 [NFATc3 knockout (KO)] prevented NFAT activation. More importantly, H-IH-induced hypertension was attenuated in cyclosporin A-treated mice and prevented in NFATc3 KO mice. MAP was significantly elevated in wild-type mice (Delta = 23.5 +/- 6.1 mmHg), but not in KO mice (Delta = -3.9 +/- 5.7). These results indicate that H-IH-induced increases in MAP require NFATc3 and that NFATc3 may contribute to the vascular changes associated with H-IH-induced hypertension.

Topics: Animals; Aorta; Blood Pressure; Calcineurin; Calcineurin Inhibitors; Cyclosporine; Disease Models, Animal; Endothelin-1; Hypertension; Hypoxia; Lung; Male; Mesenteric Arteries; Mice; Mice, Inbred BALB C; Mice, Knockout; NFATC Transcription Factors; RNA, Messenger; Sleep Apnea Syndromes; Time Factors; Transcription, Genetic; Up-Regulation

To explore the role of sympathetic nerve activity and vessel endothelial function in the pathogenesis of hypertension in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS).. Based on polysomnography (PSG), blood pressure (BP) and disease history, 93 subjects were divided into four groups: OSAHS with hypertension (OH), OSAHS without hypertension (O), hypertension without OSAHS (H), normal control (N). In addition to the blood pressure measurement, blood samples were collected before and after sleep during the PSG testing night to measure norepinephrine, endothelin, and NO levels. Urine samples were also collected during this time to test the level of vanillyl mandalic acid (VMA).. Patients in OH group and O group had significantly increased plasma NE value (P < 0.05) in the next morning compared with those before sleep and the change was more significant in OH group compared to O group (P < 0.01). Pre-and after-sleep urine VMA levels in all groups showed no significant differences. Plasma NE and ET levels in OSAHS with and without hypertension after sleep were positively correlated with mean arterial pressure (MAP), apnea-hypopnea index (AHI), number of oxygen desaturation >or= 4% per hour (ODI(4)), percentage of time of oxygen saturation lower than 90% (T90) and correlated negatively with minimum arterial oxygen saturation (minSaO(2)) and mean arterial oxygen saturation (MSaO(2)). Moreover, plasma ET also correlated positively with MAP, AHI, maximum apnea time, total apnea time. Compared with other groups plasma ET value increased significantly and serum NO value decreased in the next morning in both O and OH group. Serum NO value after one night sleep in both hypertensive and norhypertensive OSAHS patients was negatively correlated with MAP, AHI, maximum apnea time, total apnea time, ODI(4), T90, and positively with minSaO(2) and MSaO(2).. Sympathetic nerve activation and endothelial dysfuntion characterized by an imbalance of endothelium-derived systolic and diastolic factors may play an important role in the development of transient and sustained increase of blood pressure in patients with OSAHS.

Topics: Adult; Endothelin-1; Endothelium, Vascular; Female; Humans; Hypertension; Male; Middle Aged; Nitric Oxide; Norepinephrine; Polysomnography; Sleep Apnea Syndromes; Sleep Apnea, Obstructive; Sympathetic Nervous System

We reported previously that intermittent hypoxia with CO(2) to maintain eucapnia (IH-C) elevates plasma endothelin-1 (ET-1) and arterial pressure. In small mesenteric arteries (sMA; inner diameter = 150 microm), IH-C augments ET-1 constrictor sensitivity but diminishes ET-1-induced increases in intracellular Ca(2+) concentration, suggesting IH-C exposure increases both ET-1 levels and ET-1-stimulated Ca(2+) sensitization. Because Rho-associated kinase (ROK) can mediate Ca(2+) sensitization, we hypothesized that augmented vasoconstrictor sensitivity to ET-1 in arteries from IH-C-exposed rats is dependent on ROK activation. In thoracic aortic rings, ET-1 contraction was not different between groups, but ROK inhibition (Y-27632, 3 and 10 microM) attenuated ET-1 contraction more in IH-C than in sham arteries (50 +/- 11 and 78 +/- 7% vs. 41 +/- 12 and 48 +/- 9% inhibition, respectively). Therefore, ROK appears to contribute more to ET-1 contraction in IH-C than in sham aorta. In sMA, ROK inhibitors did not affect ET-1-mediated constriction in sham arteries and only modestly inhibited it in IH-C arteries. In ionomycin-permeabilized sMA with intracellular Ca(2+) concentration held at basal levels, Y-27632 did not affect ET-1-mediated constriction in either IH-C or sham sMA and ET-1 did not stimulate ROK translocation. In contrast, inhibition of myosin light-chain kinase (ML-9, 100 microM) prevented ET-1-mediated constriction in sMA from both groups. Therefore, IH-C exposure increases ET-1 vasoconstrictor sensitivity in sMA but not in aorta. Furthermore, ET-1 constriction is myosin light-chain kinase dependent and mediated by Ca(2+) sensitization that is independent of ROK activation in sMA but not aorta. Thus ET-1-mediated signaling in aorta and sMA is altered by IH-C but is dependent on different second messenger systems in small vs. large arteries.

Topics: Animals; Aorta; Dose-Response Relationship, Drug; Endothelin-1; Enzyme Activation; Hypercapnia; Hypoxia; Male; Mesenteric Arteries; Rats; Rats, Sprague-Dawley; rho-Associated Kinases; Sleep Apnea Syndromes; Vasoconstriction

In clinical studies, sleep apnea is associated with hypertension, oxidative stress, and increased circulating endothelin-1 (ET-1). We previously developed a model of sleep apnea by exposing rats to eucapnic intermittent hypoxia (IH-C) during sleep, which increases both blood pressure and plasma levels of ET-1. Because similar protocols in mice increase tissue and plasma markers of oxidative stress, we hypothesized that IH-C generation of reactive oxygen species (ROS) contributes to the development of ET-1-dependent hypertension in IH-C rats. To test this, male Sprague-Dawley rats were instrumented with indwelling blood pressure telemeters and drank either plain water or water containing the superoxide dismutase mimetic, Tempol (4-hydroxy-2,2,6,6-tetramethyl-piperidine-1-oxyl, 1 mM). Mean arterial pressure (MAP) and heart rate (HR) were recorded for 3 control days and 14 treatment days with rats exposed 7 h/day to IH-C or air/air cycling (Sham). On day 14, MAP in IH-C rats treated with Tempol (107 +/- 2.29 mmHg) was significantly lower than in untreated IH-C rats (118 +/- 9 mmHg, P < 0.05). Tempol did not affect blood pressure in sham-operated rats (Tempol = 101 +/- 3, water = 101 +/- 2 mmHg). Immunoreactive ET-1 was greater in plasma from IH-C rats compared with plasma from sham-operated rats but was not different from Sham in Tempol-treated IH-C rats. Small mesenteric arteries from IH-C rats but not Tempol-treated IH-C rats had increased superoxide levels as measured by ferric cytochrome c reduction, lucigenin signaling, and dihydroethidium fluorescence. The data show that IH-C increases ET-1 production and vascular ROS levels and that scavenging superoxide prevents both. Thus oxidative stress appears to contribute to increases in ET-1 production and elevated arterial pressure in this rat model of sleep apnea-induced hypertension.

Topics: Animals; Endothelin-1; Hypertension; Male; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Sleep Apnea Syndromes; Superoxide Dismutase

We reported previously that simulating sleep apnea in rats by exposing them 7 hours per day to intermittent hypoxia/hypercapnia (IH) elevates plasma endothelin-1 and causes hypertension, which is reversed by an endothelin-1 antagonist. We hypothesized that in this model of sleep apnea-induced hypertension, vascular sensitivity to endothelin-1 is increased in combination with the elevated plasma endothelin-1 to cause the endothelin-1-dependent hypertension. In small mesenteric arteries with endothelial function disabled by passing air through the lumen, diameter and vessel wall [Ca2+] were recorded simultaneously. IH arteries demonstrated increased constrictor sensitivity to endothelin-1 (percentage max constriction 100+/-0% IH versus 80+/-10% Sham; P<0.05). This was accompanied by increased calcium sensitivity of IH arteries. In contrast, constrictor sensitivity and increases in vessel wall [Ca2+] to KCl and phenylephrine were not different between IH and Sham arteries. We have shown previously that endothelin-1 constriction in mesenteric arteries is mediated by endothelin A receptors. In the current study, the selective increase in endothelin-1 constriction in IH resistance arteries was accompanied by increased expression of endothelin A receptor expression (densitometry units 271+/-23 IH versus 158+/-25 Sham; P<0.05). Thus, IH hypertension appears to cause alterations in signaling components unique to endothelin-1 at the receptor level and in postreceptor signaling that increases calcium sensitivity during endothelin A activation. Future studies will determine the specific changes in vascular smooth muscle signaling in IH hypertension causing this augmented contractile phenotype.

Topics: Animals; Blood Pressure; Calcium; Endothelin-1; Hypertension; Hypoxia; In Vitro Techniques; Male; Mesenteric Arteries; Phenylephrine; Potassium Chloride; Rats; Rats, Sprague-Dawley; Receptor, Endothelin A; Sleep Apnea Syndromes; Vasoconstriction; Vasoconstrictor Agents

Topics: Adult; Arrhythmias, Cardiac; Cardiovascular Diseases; Child; Comorbidity; Coronary Artery Disease; Endothelin-1; Endothelium, Vascular; Epidemiologic Studies; Genetic Predisposition to Disease; Heart Failure; Humans; Hypertension; Male; Obesity; Risk Factors; Sleep Apnea Syndromes; Sleep Apnea, Obstructive; Thrombophilia

Recurrent episodic hypoxia (EH) is a feature of sleep apnea that may be responsible for some chronic cardiovascular sequelae such as systemic hypertension. Chronic EH (8 h/day for 35 days) causes elevation of diurnal resting (unstimulated) mean arterial blood pressure (MAP) in the rat. We used in vivo video microscopy to examine arteriolar reactivity in the cremaster muscle of male Sprague-Dawley rats subjected to 35 days of EH. Cremaster muscles of EH (n = 6) and control (n = 6) rats were exposed to varying doses of norepinephrine (NE) (10(-10) to 10(-5) M), ACh (10(-9) to 10(-5) M), and endothelin-1 (10(-12) to 10(-8) M). In a separate experiment, EH (n = 5) and control (n = 6) rats were given one dose of a nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME; 10(-5) M). We also examined endothelial NOS mRNA from the kidneys of EH-stimulated and control (unstimulated) rats. Telemetry-monitored EH rats showed a 16-mmHg increase in MAP over 35 days, whereas control rats showed no change. The response to NE and endothelin-1 were similar for EH and control rats. ACh vasodilatation of arterioles in EH rats was significantly attenuated compared with that of controls. The degree of vasoconstriction in response to blockade of the nitric oxide system by L-NAME was significantly less (83% of baseline diameter with L-NAME) for arterioles of EH rats compared with that for controls (61% of baseline diameter), implying lower basal resting nitric oxide release in the EH rats. Whole kidney mRNA endothelial NOS levels were not different between groups. These data support the hypothesis that chronic elevation of blood pressure associated with EH involves increased peripheral resistance from decreased basal release or production of nitric oxide after 35 days of EH.

Topics: Acetylcholine; Animals; Arterioles; Blood Pressure; Chronic Disease; Circadian Rhythm; Disease Models, Animal; Endothelin-1; Gene Expression Regulation, Enzymologic; Hypoxia; Kidney; Male; NG-Nitroarginine Methyl Ester; Nitric Oxide Synthase; Nitric Oxide Synthase Type III; Norepinephrine; Rats; Rats, Sprague-Dawley; Sleep Apnea Syndromes; Telemetry; Transcription, Genetic; Vasodilation

Endothelin-1 (ET-1), a potent vasoconstrictor, is released mainly by vascular endothelial cells under the influence of hypoxia and other stimuli. ET-1 is related to endothelial dysfunction, as well as arterial and pulmonary hypertension, all of which are thought to be associated with obstructive sleep apnoea (OSA). This study evaluated venous plasma concentrations of ET-1 and noradrenaline and 24-h systemic blood pressure in 29 patients with OSA (age=56.9+/-1.6 yrs; body mass index=29.5+/-0.7 kg x m2 (mean+/-SEM)). Blood samples were taken in the morning, evening and during sleep. In the same way, the patients were assessed during a night of continuous positive airway pressure (CPAP) and after 13.9+/-1.4 months while still on CPAP. ET-1 levels were compared to those of control subjects, who were selected from in- and outpatients and were matched to patients for age, sex, presence of arterial hypertension and coronary artery disease. ET-1 plasma levels were not elevated in the patients compared to the controls (41.6+/-2.2 and 44.9+/-1.3 pg x mL(-1), respectively, p=0.20). The ET-1 concentration did not change significantly, neither during sleep nor in the first night on CPAP therapy, nor under long-term treatment with CPAP. ET-1 neither correlated to the severity of OSA nor to that of systemic hypertension. The results suggest that endothelin-1 does not play a crucial role in the pathophysiology of obstructive sleep apnoea.

Topics: Blood Pressure Monitoring, Ambulatory; Case-Control Studies; Endothelin-1; Female; Humans; Male; Middle Aged; Norepinephrine; Polysomnography; Positive-Pressure Respiration; Sleep Apnea Syndromes; Time Factors

Topics: Cardiovascular Diseases; Endothelin-1; Humans; Sleep Apnea Syndromes

To evaluate blood pressure and humoral vasoconstrictor responses to recurrent episodes of obstructive sleep apnea and the effects of therapy by means of continuous positive airway pressure.. We prospectively evaluated overnight changes in hemodynamics, oxygen saturation, the apnea-hypopnea index, circulating endothelin-1, norepinephrine and plasma renin activity in 22 patients with severe obstructive sleep apnea before and after successful therapy using continuous positive airway pressure therapy (three measurements). Measurements of endothelin-1 and blood pressure were also obtained on three occasions, at similar times, in 12 healthy control subjects without sleep disturbances.. Mean arterial pressure and endothelin-1 concentrations increased significantly after 4 h of untreated obstructive sleep apnea, and decreased after 5 h of continuous positive airway pressure. Changes in endothelin-1 levels were correlated with changes in mean arterial pressure (r = 0.44, P < 0.02) and with changes in oxygen saturation (r = 0.37, P < 0.05). Norepinephrine levels and plasma renin activity did not change significantly in patients with obstructive sleep apnea, and were not correlated with changes in blood pressure or oxygen saturation. In controls, blood pressure measurements at similar times during the night showed changes directionally opposite to that seen in obstructive sleep apnea, while endothelin-1 levels remained unchanged.. Sleep apnea elicits increases in blood pressure and endothelin-1, with reductions in both after treatment. Vasoconstrictor and mitogenic effects of endothelin-1 may be implicated in increased cardiovascular risk in patients with obstructive sleep apnea.

Topics: Angiotensin I; Biomarkers; Blood Gas Analysis; Blood Pressure; Catecholamines; Endothelin-1; Female; Follow-Up Studies; Humans; Male; Middle Aged; Positive-Pressure Respiration; Prospective Studies; Radioimmunoassay; Recurrence; Renin; Sleep Apnea Syndromes

Endothelin (ET)-1 is a potent vasoconstrictive and mitogenic peptide produced by endothelial cells and degraded predominantly in pulmonary vasculature. We measured ET-1 in 9-normotensive and 14 hypertensive men with obstructive sleep apnea. The ET-1 levels were higher in both normotensive (mean +/- SD, 6.3 +/- 2.8 pg/ml) and hypertensive (7.8 +/- 3.0 pg/ml) groups than in 66 healthy controls (2.9 +/- 1.2 pg/ml). Ten patients were restudied after three months of nCPAP treatment. No decrease in ET-1 was observed.

Topics: Adult; Airway Obstruction; Endothelin-1; Endothelium, Vascular; Humans; Hypertension; Male; Middle Aged; Obesity; Polysomnography; Positive-Pressure Respiration; Sleep Apnea Syndromes