scholarly journals Blood Pressure Response in Miners Exposed to Chronic Intermittent Hypoxia in Chile

2021 ◽  
Vol 8 ◽  
Author(s):  
Morin Lang ◽  
Valeria Paéz ◽  
Giacomo Maj ◽  
Juan Silva-Urra ◽  
Cristián Labarca-Valenzuela ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Intermittent Hypoxia ◽  
Blood Pressure Response ◽  
Current Therapy ◽  
Chronic Intermittent Hypoxia ◽  
Limited Information ◽  
Altitude Sickness ◽  
Shift Pattern ◽  
History Of ◽  
Cardiovascular Variables

Introduction: Limited information is available on blood pressure (BP) behavior in workers exposed to chronic intermittent hypoxia (CIH), and even less is known regarding effects of CIH on 24-h ambulatory BP in those affected by arterial hypertension at sea level (SL). The aims of this study were to assess clinic and 24-h ambulatory BP at SL and at high altitude (HA; 3,870 m above SL) in workers exposed to CIH, and to compare BP response to HA exposure between normotensive and hypertensive workers.Methods: Nineteen normotensive and 18 pharmacologically treated hypertensive miners acclimatized to CIH were included, whose work was organized according to a “7 days-on−7 days-off” shift pattern between SL and HA. All measurements were performed on the second and seventh day of their HA shift and after the second day of SL sojourn.Results: Compared to SL, 24-h systolic BP (SBP) and diastolic BP (DBP) increased at HA [+14.7 ± 12.6 mmHg (p < 0.001) and +8.7 ± 7.2 mmHg (p < 0.001), respectively], and SBP nocturnal fall decreased consistently (−4.1 ± 9.8%; p < 0.05) in all participants, with hypertensives showing higher nocturnal DBP than normotensives (p < 0.05) despite the current therapy. Also, heart rate (HR) nocturnal fall tended to be reduced at HA. In addition, the 24-h SBP/DBP hypertension threshold of ≥130/80 mmHg was exceeded by 39% of workers at SL and by 89% at HA. Clinic HR, SBP, and DBP were significantly higher on the second day of work at HA compared with SL, the increase being more pronounced for SBP in hypertensives (p < 0.05) and accompanied by, on average, mild altitude sickness in both groups. These symptoms and the values of all cardiovascular variables decreased on the seventh day at HA (p < 0.05) regardless of CIH exposure duration.Conclusion: Long history of work at HA according to scheduled CIH did not prevent the occurrence of acute cardiovascular changes at HA during the first days of exposure. The BP response to HA tended to be more pronounced in hypertensive than in normotensive workers despite being already treated; the BP changes were more evident for 24-h ambulatory BP. Twenty-four-hour ABP monitoring is a useful tool for an appropriate evaluation of BP in CIH workers.

scholarly journals Chronic intermittent hypoxia in humans during 28 nights results in blood pressure elevation and increased muscle sympathetic nerve activity

2010 ◽  
Vol 299 (3) ◽  
pp. H925-H931 ◽  
Author(s):  
G. S. Gilmartin ◽  
M. Lynch ◽  
R. Tamisier ◽  
J. W. Weiss
Keyword(s):  
Blood Pressure ◽  
Sympathetic Nerve ◽  
Intermittent Hypoxia ◽  
Sympathetic Nerve Activity ◽  
Muscle Sympathetic Nerve Activity ◽  
Chronic Intermittent Hypoxia ◽  
Sympathetic Activation ◽  
Nerve Activity ◽  
Blood Pressure Elevation ◽  
Healthy Humans

Chronic intermittent hypoxia (CIH) is thought to be responsible for the cardiovascular disease associated with obstructive sleep apnea (OSA). Increased sympathetic activation, altered vascular function, and inflammation are all putative mechanisms. We recently reported (Tamisier R, Gilmartin GS, Launois SH, Pepin JL, Nespoulet H, Thomas RJ, Levy P, Weiss JW. J Appl Physiol 107: 17–24, 2009) a new model of CIH in healthy humans that is associated with both increases in blood pressure and augmented peripheral chemosensitivity. We tested the hypothesis that exposure to CIH would also result in augmented muscle sympathetic nerve activity (MSNA) and altered vascular reactivity contributing to blood pressure elevation. We therefore exposed healthy subjects between the ages of 20 and 34 yr ( n = 7) to 9 h of nocturnal intermittent hypoxia for 28 consecutive nights. Cardiovascular and hemodynamic variables were recorded at three time points; MSNA was collected before and after exposure. Diastolic blood pressure (71 ± 1.3 vs. 74 ± 1.7 mmHg, P < 0.01), MSNA [9.94 ± 2.0 to 14.63 ± 1.5 bursts/min ( P < 0.05); 16.89 ± 3.2 to 26.97 ± 3.3 bursts/100 heartbeats (hb) ( P = 0.01)], and forearm vascular resistance (FVR) (35.3 ± 5.8 vs. 55.3 ± 6.5 mmHg·ml−1·min·100 g tissue, P = 0.01) all increased significantly after 4 wk of exposure. Forearm blood flow response following ischemia of 15 min (reactive hyperemia) fell below baseline values after 4 wk, following an initial increase after 2 wk of exposure. From these results we conclude that the increased blood pressure following prolonged exposure to CIH in healthy humans is associated with sympathetic activation and augmented FVR.

scholarly journals Maternal History of Hypertension and Blood Pressure Response to Potassium Intake: The GenSalt Study

2012 ◽  
Vol 176 (suppl 7) ◽  
pp. S55-S63 ◽  
Author(s):  
T. N. Kelly ◽  
D. Gu ◽  
D. C. Rao ◽  
J. Chen ◽  
J. Chen ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Pressure Response ◽  
Pressure Response ◽  
Maternal History ◽  
Potassium Intake ◽  
History Of

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.

Attenuation of Electroconvulsive Therapy Induced Hypertension with Sublingual Nifedipine

1989 ◽  
Vol 17 (1) ◽  
pp. 31-33 ◽  
Author(s):  
D. G. Wells ◽  
G. G. Davies ◽  
F. Rosewarne
Keyword(s):  
Blood Pressure ◽  
Electroconvulsive Therapy ◽  
Blood Pressure Response ◽  
Pressor Response ◽  
Systolic Pressure ◽  
Response To Therapy ◽  
Induced Hypertension ◽  
Sublingual Nifedipine ◽  
History Of ◽  
Significant Attenuation

Five patients known to be previously hypertensive but not currently receiving anti-hypertensive medications were studied for a total of twenty-six administrations of electroconvulsive therapy Patients randomly received sublingual nifedipine 10 mg, 20 minutes prior to half of their treatments, and for the remaining treatments acted as their own controls. The use of nifedipine resulted in significant attenuation of the blood pressure response to therapy. Systolic pressure increase was 24 mmHg (SD 14) versus 62 mmHg (SD 24) (P< 0.01). There was no difference in heart rate between the two groups. It is concluded that nifedipine reduces the pressor response to electroconvulsive therapy in individuals with a history of hypertension.

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