Combined intermittent and sustained hypoxia is a novel and deleterious cardio-metabolic phenotype

SLEEP ◽  
2021 ◽  
Author(s):  
Xin Zhen ◽  
Esteban A Moya ◽  
Mary Gautane ◽  
Huayi Zhao ◽  
Elijah S Lawrence ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Intermittent Hypoxia ◽  
Systolic Pressure ◽  
Metabolic Effects ◽  
Metabolic Phenotype ◽  
Glucose Disposal ◽  
Chronic Obstructive ◽  
Ventricular Systolic Pressure ◽  
Obstructive Sleep ◽  
Sustained Hypoxia

Abstract Study objectives Chronic obstructive pulmonary disease and obstructive sleep apnea overlap syndrome is associated with excess mortality, and outcomes are related to the degree of hypoxemia. People at high altitude are susceptible to periodic breathing, and hypoxia at altitude is associated with cardio-metabolic dysfunction. Hypoxemia in these scenarios may be described as superimposed sustained plus intermittent hypoxia, or overlap hypoxia (OH), the effects of which have not been investigated. We aimed to characterize the cardio-metabolic consequences of OH in mice. Methods C57BL/6J mice were subjected to either sustained hypoxia (SH, FiO2=0.10), intermittent hypoxia (IH, FiO2=0.21 for 12 hours, and FiO2 oscillating between 0.21 and 0.06, 60 times/hour, for 12 hours), OH (FiO2=0.13 for 12 hours, and FiO2 oscillating between 0.13 and 0.06, 60 times/hour, for 12 hours), or room air (RA), n=8/group. Blood pressure and intraperitoneal glucose tolerance test were measured serially, and right ventricular systolic pressure (RVSP) was assessed. Results Systolic blood pressure transiently increased in IH and OH relative to SH and RA. RVSP did not increase in IH, but increased in SH and OH by 52% (p<0.001) and 20% (p=0.001). Glucose disposal worsened in IH and improved in SH, with no change in OH. Serum LDL and VLDL increased in OH and SH, but not in IH. Hepatic oxidative stress increased in all hypoxic groups, with the highest increase in OH. Conclusions Overlap hypoxia may represent a unique and deleterious cardio-metabolic stimulus, causing systemic and pulmonary hypertension, and without protective metabolic effects characteristic of sustained hypoxia.

Short-term intermittent hypoxia enhances sympathetic responses to continuous hypoxia in humans

2007 ◽  
Vol 103 (3) ◽  
pp. 835-842 ◽  
Author(s):  
Urs A. Leuenberger ◽  
Cynthia S. Hogeman ◽  
Sadeq Quraishi ◽  
Latoya Linton-Frazier ◽  
Kristen S. Gray
Keyword(s):  
Blood Pressure ◽  
Sleep Apnea ◽  
Sympathetic Activity ◽  
Intermittent Hypoxia ◽  
Muscle Sympathetic Nerve Activity ◽  
Acute Hypoxia ◽  
Short Term ◽  
Healthy Humans ◽  
Obstructive Sleep ◽  
Normal Humans

Short-term intermittent hypoxia leads to sustained sympathetic activation and a small increase in blood pressure in healthy humans. Because obstructive sleep apnea, a condition associated with intermittent hypoxia, is accompanied by elevated sympathetic activity and enhanced sympathetic chemoreflex responses to acute hypoxia, we sought to determine whether intermittent hypoxia also enhances chemoreflex activity in healthy humans. To this end, we measured the responses of muscle sympathetic nerve activity (MSNA, peroneal microneurography) to arterial chemoreflex stimulation and deactivation before and following exposure to a paradigm of repetitive hypoxic apnea (20 s/min for 30 min; O2 saturation nadir 81.4 ± 0.9%). Compared with baseline, repetitive hypoxic apnea increased MSNA from 113 ± 11 to 159 ± 21 units/min ( P = 0.001) and mean blood pressure from 92.1 ± 2.9 to 95.5 ± 2.9 mmHg ( P = 0.01; n = 19). Furthermore, compared with before, following intermittent hypoxia the MSNA (units/min) responses to acute hypoxia [fraction of inspired O2 (FiO2) 0.1, for 5 min] were enhanced (pre- vs. post-intermittent hypoxia: +16 ± 4 vs. +49 ± 10%; P = 0.02; n = 11), whereas the responses to hyperoxia (FiO2 0.5, for 5 min) were not changed significantly ( P = NS; n = 8). Thus 30 min of intermittent hypoxia is capable of increasing sympathetic activity and sensitizing the sympathetic reflex responses to hypoxia in normal humans. Enhanced sympathetic chemoreflex activity induced by intermittent hypoxia may contribute to altered neurocirculatory control and adverse cardiovascular consequences in sleep apnea.

scholarly journals Superior hypertension control with betablockade in the European Sleep Apnea Database

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
S Svedmyr ◽  
J Hedner ◽  
D Zou ◽  
G Parati ◽  
S Ryan ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Sleep Apnea ◽  
Systolic Blood Pressure ◽  
Research Collaboration ◽  
Antihypertensive Drugs ◽  
Systolic Pressure ◽  
Apnea Hypopnea Index ◽  
Funding Source ◽  
Obstructive Sleep ◽  
Adjusted Model

Abstract Background Arterial hypertension is highly prevalent and frequently difficult to control in patients with obstructive sleep apnea (OSA). High sympathetic activity is a hallmark physiological phenomenon in OSA. We hypothesized that antihypertensive drugs with sympathetic inhibitory properties, in particular beta blockers (BB), may be particularly efficacious in OSA patients. Methods Hypertensive OSA patients receiving blood pressure lowing treatment in the European Sleep Apnea Database (ESADA) were analyzed (n=5818, 69% men, age 58±11 years, body mass index 33±7 kg/m2, apnea hypopnea index 34±26 events/h). Antihypertensive medications (BB, diuretic, renin-angiotensin blocker [RAB], calcium channel blocker [CCB], and centrally acting antihypertensive [CAH]) were classified according to ATC code. Office blood pressure was compared in patients with mono- or combination therapy controlling for confounders. Results Poorly controlled systolic blood pressure according to the ESC/ESH guidelines was found in 66% of patients. Patients receiving monotherapy with RAB, CCB or CAH had 2.2 [95% CI, 1.4–3.0], 3.0 [1.9–4.1] and 3.0 [1.7–4.7] mmHg higher systolic blood pressure compared with those on BB (adjusted model, p=0.007, 0.008 and 0.017, respectively). In those with a combination of two antihypertensive drugs, systolic blood pressure was 3.3 [2.4–4.3], 2.2 [1.3–4.3] and 2.3 [1.4–3.3] mmHg higher in those on CCB/RAB, diuretic/RAB or BB/RAB compared with those on BB/diuretic (adjusted model, p<0.001, 0.019 and 0.001, respectively). Conclusions Uncontrolled blood pressure was common in OSA patients with antihypertensive medication. Patients treated with BB alone or in combination with diuretic was associated with a lower systolic pressure in this large clinical cohort. Funding Acknowledgement Type of funding source: Other. Main funding source(s): European Respiratory Society funded Clinical Research Collaboration (2015-2020)

The effect of endogenous estrogen on Doppler-estimated right ventricular systolic pressure during exercise

2012 ◽  
Vol 90 (10) ◽  
pp. 1364-1371
Author(s):  
Vicki N. Wang ◽  
Mavra Ahmed ◽  
Amelia Ciofani ◽  
Zion Sasson ◽  
John T. Granton ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Menstrual Cycle ◽  
Right Ventricular ◽  
Systolic Pressure ◽  
Rate Pressure Product ◽  
Right Ventricular Systolic Pressure ◽  
Ventricular Systolic Pressure ◽  
Early Exercise ◽  
Endogenous Estrogen ◽  
Response To Exercise

We evaluated the effect of endogenous estrogen levels on exercise-related changes in right ventricular systolic pressure (RVSP) of healthy, eumenorrheic, sedentary women. Volunteers were studied at two separates phases of the menstrual cycle (LO and HI estrogen phases), exercised on a semi-supine ergometer with escalating workload and monitored continuously by 12-lead ECG and automated blood pressure cuff. At each exercise stage, Doppler echocardiography measurements were obtained and analyzed to determine RVSP. Fourteen subjects (age 24 ± 5) were studied. Exercise duration was significantly higher on the HI estrogen day, but no significant differences in hemodynamic response to exercise were found between the two study days. There were also no significant differences with respect to heart rate (HR) acceleration during early exercise, as well as resting and peak RVSP, HR, blood pressure, and rate pressure product. Doppler-estimated RVSP demonstrated a linear relationship to HR at a ratio of 1 mm Hg (1 mm Hg = 133.3224 Pa) for every 5 bpm (beats per minute) increase in HR. There were no differences in the slope of this relationship between HI and LO estrogen phases of the menstrual cycle. Our findings did not demonstrate any effect of endogenous estrogen levels on the modulation of the pulmonary vascular response to exercise in healthy women.

scholarly journals Chylothorax: complication attributed to dasatinib use

2019 ◽  
Vol 12 (12) ◽  
pp. e231653 ◽  
Author(s):  
Abdullah Al-abcha ◽  
Mian Harris Iftikhar ◽  
Fawzi Abu Rous ◽  
Heather Laird-Fick
Keyword(s):  
Ejection Fraction ◽  
Pleural Fluid ◽  
Systolic Pressure ◽  
Symptomatic Improvement ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Ventricular Systolic Pressure ◽  
Fluid Analysis ◽  
Ct Angiogram ◽  
History Of

A 63-year-old woman with a medical history of chronic myelogenous leukaemia treated with dasatinib, chronic obstructive pulmonary disease and heart failure with preserved ejection fraction presented with difficulty in breathing. Chest X-ray showed large right-sided pleural effusion, which was confirmed on a CT angiogram of the chest. Echocardiogram showed an ejection fraction of 61% with moderate to severely dilated right ventricle and right ventricular systolic pressure of 60 mm Hg. Diagnostic and therapeutic thoracentesis was performed, and 2.2 L of pleural fluid was removed. Pleural fluid analysis was consistent with chylothorax. Significant symptomatic improvement was noted after thoracentesis. In the absence of an alternate explanation, chylothorax was attributed to dasatinib, which was switched to nilotinib. This resulted in resolution of her pleural effusions.

The effect of milrinone on hemodynamic and gas exchange parameters in children

2019 ◽  
Vol 30 (1) ◽  
pp. 55-61
Author(s):  
Rohit S. Loomba ◽  
Vincent Dorsey ◽  
Enrique G. Villarreal ◽  
Saul Flores
Keyword(s):  
Blood Pressure ◽  
Critical Illness ◽  
Systolic Pressure ◽  
Serum Lactate ◽  
Arterial Oxygen ◽  
Hemodynamic Effects ◽  
Gas Exchange Parameters ◽  
Ventricular Systolic Pressure ◽  
Hemodynamic Support ◽  
Arterial Blood

AbstractMilrinone is a drug frequently used for hemodynamic support in children during critical illness. Although the hemodynamic changes induced by milrinone in children may appear similar to those of adults, the physiologic contributors of these changes remain vastly unknown. A systematic review was conducted to identify studies characterising the hemodynamic effects of milrinone in children during critical illness for hemodynamic support for various medical conditions. Studies were assessed for quality and those of satisfactory quality with pre- and post-operative hemodynamics for each patient were included in the final analyses. Those not limited to children and those not limited to patients with critical illness were excluded from the final analyses. A total of six studies with 791 patients were included in the final analyses. Milrinone infusion doses ranged from 0.3 to 0.75 mcg/kg/minute with the mean infusion dose being 0.5 mcg/kg/minute. Patients whom received milrinone infusion had greater cardiac output, greater left ventricle shortening fraction, lower right ventricular systolic pressure, and lower serum lactate levels. Systolic blood pressure mean arterial blood pressure and arterial oxygen concentration did not significantly change with administration of milrinone. These results were irrespective of milrinone infusion dose, infusion duration, and study size. Milrinone was found to have several beneficial hemodynamic effects in children during critical illness when used at usual clinical doses.

Modulation of cardiovascular response to dynamic exercise by fastigial nucleus

1984 ◽  
Vol 56 (5) ◽  
pp. 1369-1377 ◽  
Author(s):  
K. J. Dormer
Keyword(s):  
Blood Pressure ◽  
Repeated Measures ◽  
Cardiovascular Response ◽  
Systolic Pressure ◽  
Cardiovascular Responses ◽  
Left Ventricular ◽  
Dynamic Exercise ◽  
Fastigial Nucleus ◽  
Ventricular Systolic Pressure ◽  
Arterial Blood

Mongrel dogs (n = 34) were used to record the cardiovascular responses during submaximal exercise-tolerance tests (ETT) before and after the placement of lesions in rostral portions of the cerebellar fastigial nucleus (FN). Sterile surgical procedures were used to implant solid-state pressure transducers into the left ventricle or descending aorta (anesthesia 1% halothane in O2) and multipolar stainless steel electrodes into FN (anesthesia alpha-chloralose 115 mg/kg iv). Heart rate (HR), maximal left ventricular systolic pressure ( LVPmax ) and its first derivative ( dLVP /dt), and mean arterial blood pressure (MAP) were recorded during a motorized treadmill ETT. Electrolytic direct-current or radio-frequency lesions were made through the indwelling FN electrodes, and the ETT was repeated following 10–14 days recovery. Two-way analysis of variance (ANOVA), with repeated measures on one, and one-way ANOVA for simple effects indicated a significant reduction in HR and MAP (P less than 0.01) but not LVPmax and dLVP /dt occurred during exercise as a result of rostral FN lesions. Although the trend for reduced LVPmax and dLVP /dt was also evident, a relatively greater decrease in blood pressure occurred in the peripheral vasculature during exercise. It was concluded that FN acts as a modulator of HR and MAP during dynamic exercise because of the observed deficits, and because FN is known to both send efferent projections to medullary vasomotor areas and receive projections from motor cortex and muscle and joint afferents.

Increased cardiac contractility in acute uremia: interrelationships with hypertension

1975 ◽  
Vol 229 (2) ◽  
pp. 501-505 ◽  
Author(s):  
T Nivatpumin ◽  
T Yipintsoi ◽  
S Penpargkul ◽  
J Scheuer
Keyword(s):  
Blood Pressure ◽  
Systolic Hypertension ◽  
Diastolic Pressure ◽  
Cardiac Contractility ◽  
Systolic Pressure ◽  
Pressure Rise ◽  
Left Ventricular ◽  
Ventricular Systolic Pressure ◽  
Inotropic State ◽  
Left Ventricular Systolic Pressure

To study the effects of acute uremia on the inotropic state of the rat heart, we subjected rats to bilateral nephrectomy and studied their hearts in the open chest 24 h later. Uremic rats had significantly higher systolic blood pressure than sham-operated animals. Left ventricular systolic pressure and maximum dP/dt, both during ejection and isovolumic contrations, were higher for any given end-diastolic pressure in hearts of uremic rats than in sham-operated animals. This difference in performance charcteristics was not abolished by doses of propranolol that blocked the heart rate response to isoproterenol. The administration of phenoxybenzamine during the 24 h of uremia abolished the blood pressure rise in uremic rats, but the increased contractile state persisted. Treatment of sham-operated animals with methoxamine to produce the same course of blood pressure as observed in uremic rats was also associated with an increased inotropic state. These results indicate that in the rat, acute uremia is associated with an increased inotropic state that is not mediated by beta-adrenergic mechanisms. The systolic hypertension of acute uremia is not the major cause of the increased contractility, although systolic hypertension without uremia can mimic the performance characteristics found in hearts of uremic rats.

Invited Review: Physiological consequences of intermittent hypoxia: systemic blood pressure

2001 ◽  
Vol 90 (4) ◽  
pp. 1600-1605 ◽  
Author(s):  
Eugene C. Fletcher
Keyword(s):  
Blood Pressure ◽  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Intermittent Hypoxia ◽  
Cardiovascular Response ◽  
Acute Hypoxia ◽  
Renin Angiotensin System ◽  
Systemic Blood Pressure ◽  
Angiotensin Ii Receptor ◽  
Obstructive Sleep

One of the major manifestations of obstructive sleep apnea is profound and repeated hypoxia during sleep. Acute hypoxia leads to stimulation of the peripheral chemoreceptors, which in turn increases sympathetic outflow, acutely increasing blood pressure. The chronic effect of these repeated episodic or intermittent periods of hypoxia in humans is difficult to study because chronic cardiovascular changes may take many years to manifest. Rodents have been a tremendous source of information in short- and long-term studies of hypertension and other cardiovascular diseases. Recurrent short cycles of normoxia-hypoxia, when administered to rats for 35 days, allows examination of the chronic cardiovascular response to intermittent hypoxia patterned after the episodic desaturation seen in humans with sleep apnea. The result of this type of intermittent hypoxia in rats is a 10- to 14-mmHg increase in resting (unstimulated) mean blood pressure that lasts for several weeks after cessation of the daily cyclic hypoxia. Carotid body denervation, sympathetic nerve ablation, renal sympathectomy, adrenal medullectomy, and angiotensin II receptor blockade block the blood pressure increase. It appears that adrenergic and renin-angiotensin system overactivity contributes to the early chronic elevated blood pressure in rat intermittent hypoxia and perhaps to human hypertension associated with obstructive sleep apnea.

Mild sustained and intermittent hypoxia induce apoptosis in PC-12 cells via different mechanisms

2005 ◽  
Vol 288 (3) ◽  
pp. C535-C542 ◽  
Author(s):  
Evelyne Gozal ◽  
L. R. Sachleben ◽  
M. J. Rane ◽  
C. Vega ◽  
D. Gozal
Keyword(s):  
Intermittent Hypoxia ◽  
Cell Injury ◽  
Neuronal Damage ◽  
Brain Regions ◽  
Similar Degree ◽  
Caspase Inhibition ◽  
Obstructive Sleep ◽  
General Caspase Inhibitor ◽  
Induced Apoptosis ◽  
Sustained Hypoxia

Episodic hypoxia, a characteristic feature of obstructive sleep apnea, induces cellular changes and apoptosis in brain regions associated with neurocognitive function. To investigate whether mild, intermittent hypoxia would induce more extensive neuronal damage than would a similar degree of sustained hypoxia, rat pheochromocytoma PC-12 neuronal cells were subjected to either sustained (5% O2) or intermittent (alternating 5% O2 35 min, 21% O2 25 min) hypoxia for 2 or 4 days. Quantitative assessment of apoptosis showed that while mild sustained hypoxia did not significantly increase cell apoptosis at 2 days (1.31 ± 0.29-fold, n = 8; P = NS), a significant increase in apoptosis occurred after 4 days (2.25 ± 0.4-fold, n = 8; P < 0.002), without increased caspase activation. Furthermore, caspase inhibition with the general caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (Z-VAD-FMK) did not modify sustained hypoxia-induced apoptosis. In contrast, mild, intermittent hypoxia induced significant increases in apoptosis at 2 days (3.72 ± 1.43-fold, n = 8; P < 0.03) and at 4 days (4.57 ± 0.82-fold, n = 8; P < 0.001) that was associated with enhanced caspase activity and attenuated by Z-VAD-FMK pretreatment. We conclude that intermittent hypoxia induces an earlier and more extensive apoptotic response than sustained hypoxia and that this response is at least partially dependent on caspase-mediated pathways. In contrast, caspases do not seem to play a role in sustained hypoxia-induced apoptosis. These findings suggest that different signaling pathways are involved in sustained and intermittent hypoxia-induced cell injury and may contribute to the understanding of differential brain susceptibility to sustained and intermittent hypoxia.

scholarly journals Caspase lesions of PVN-projecting MnPO neurons block the sustained component of CIH-induced hypertension in adult male rats

2020 ◽  
Vol 318 (1) ◽  
pp. H34-H48
Author(s):  
Alexandria B. Marciante ◽  
Lei A. Wang ◽  
Joel T. Little ◽  
J. Thomas Cunningham
Keyword(s):  
Blood Pressure ◽  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Intermittent Hypoxia ◽  
Chronic Intermittent Hypoxia ◽  
Chronic Hypertension ◽  
Pressure Regulation ◽  
Neurogenic Hypertension ◽  
Obstructive Sleep ◽  
Induced Hypertension

Obstructive sleep apnea is characterized by interrupted breathing that leads to cardiovascular sequelae including chronic hypertension that can persist into the waking hours. Chronic intermittent hypoxia (CIH), which models the hypoxemia associated with sleep apnea, is sufficient to cause a sustained increase in blood pressure that involves the central nervous system. The median preoptic nucleus (MnPO) is an integrative forebrain region that contributes to blood pressure regulation and neurogenic hypertension. The MnPO projects to the paraventricular nucleus (PVN), a preautonomic region. We hypothesized that pathway-specific lesions of the projection from the MnPO to the PVN would attenuate the sustained component of chronic intermittent hypoxia-induced hypertension. Adult male Sprague-Dawley rats (250–300 g) were anesthetized with isoflurane and stereotaxically injected bilaterally in the PVN with a retrograde Cre-containing adeno-associated virus (AAV; AAV9.CMV.HI.eGFP-Cre.WPRE.SV40) and injected in the MnPO with caspase-3 (AAV5-flex-taCasp3-TEVp) or control virus (AAV5-hSyn-DIO-mCherry). Three weeks after the injections the rats were exposed to a 7-day intermittent hypoxia protocol. During chronic intermittent hypoxia, controls developed a diurnal hypertension that was blunted in rats with caspase lesions. Brain tissue processed for FosB immunohistochemistry showed decreased staining with caspase-induced lesions of MnPO and downstream autonomic-regulating nuclei. Chronic intermittent hypoxia significantly increased plasma levels of advanced oxidative protein products in controls, but this increase was blocked in caspase-lesioned rats. The results indicate that PVN-projecting MnPO neurons play a significant role in blood pressure regulation in the development of persistent chronic intermittent hypoxia hypertension. NEW & NOTEWORTHY Chronic intermittent hypoxia associated with obstructive sleep apnea increases oxidative stress and leads to chronic hypertension. Sustained hypertension may be mediated by angiotensin II-induced neural plasticity of excitatory median preoptic neurons in the forebrain that project to the paraventricular nucleus of the hypothalamus. Selective caspase lesions of these neurons interrupt the drive for sustained hypertension and cause a reduction in circulating oxidative protein products. This indicates that a functional connection between the forebrain and hypothalamus is necessary to drive diurnal hypertension associated with intermittent hypoxia. These results provide new information about central mechanisms that may contribute to neurogenic hypertension.

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