Serum erythropoietin in humans at high altitude and its relation to plasma renin

1985 ◽  
Vol 59 (2) ◽  
pp. 360-364 ◽  
Author(s):  
J. S. Milledge ◽  
P. M. Cotes
Keyword(s):  
Plasma Renin Activity ◽  
High Altitude ◽  
Sea Level ◽  
Plasma Renin ◽  
Western China ◽  
Level Control ◽  
Mount Everest ◽  
Altitude Exposure ◽  
Serum Erythropoietin ◽  
Secondary Polycythemia

Serum immunoreactive erythropoietin (siEp) was estimated in samples collected from members of two scientific and mountaineering expeditions, to Mount Kongur in Western China and to Mount Everest in Nepal. SiEp was increased above sea-level control values 1 and 2 days after arrival at 3,500 m and remained high on ascent to 4,500 m. Thereafter, while subjects remained at or above 4,500 m, siEp declined, and by 22 days after the ascent to 4,500 m was at control values but increased on ascent to higher altitude. Thus siEp was at a normal level during the maintenance of secondary polycythemia from high-altitude exposure. On descent, with removal of altitude hypoxia, siEp decreased, but despite secondary polycythemia levels remained measurable and in the range found in subjects normally resident at sea level. On Mount Everest, siEp was significantly (P less than 0.01) elevated above preexpedition sea-level controls after 2–4 wk at or above 6,300 m. There was no correlation between estimates of siEp and plasma renin activity in samples collected before and during both expeditions.

Global REACH 2018: Volume regulation in high-altitude Andeans with and without chronic mountain sickness

2021 ◽  
Author(s):  
Andrew R. Steele ◽  
Michael M. Tymko ◽  
Victoria L. Meah ◽  
Lydia L Simpson ◽  
Christopher Gasho ◽  
...  
Keyword(s):  
Glomerular Filtration Rate ◽  
Plasma Renin Activity ◽  
High Altitude ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Plasma Renin ◽  
Renin Activity ◽  
Chronic Mountain Sickness ◽  
Plasma Aldosterone Concentration ◽  
Mountain Sickness

The high-altitude maladaptation syndrome known as chronic mountain sickness (CMS) is characterized by polycythemia and is associated with proteinuria despite unaltered glomerular filtration rate. However, it remains unclear if indigenous highlanders with CMS have altered volume regulatory hormones. We assessed N-terminal pro-B-type natriuretic peptide (NT pro-BNP), plasma aldosterone concentration, plasma renin activity, kidney function (urinary microalbumin, glomerular filtration rate), blood volume, and estimated pulmonary artery systolic pressure (ePASP), in Andean males without (n=14; age=39±11) and with (n=10; age=40±12) CMS at 4330 meters (Cerro de Pasco, Peru). Plasma renin activity (non-CMS: 15.8±7.9 vs. CMS: 8.7±5.4 ng/ml; p=0.025) and plasma aldosterone concentration (non-CMS: 77.5±35.5 vs. CMS: 54.2±28.9 pg/ml; p=0.018) were lower in highlanders with CMS compared to non-CMS, while NT pro-BNP was not different between groups (non-CMS: 1394.9±214.3 vs. CMS: 1451.1±327.8 pg/ml; p=0.15). Highlanders had similar total blood volume (non-CMS: 90±15 vs. CMS: 103±18 ml • kg-1; p=0.071), but Andeans with CMS had greater total red blood cell volume (non-CMS: 46±10 vs. CMS 66±14 ml • kg-1; p<0.01) and smaller plasma volume (non-CMS 43±7 vs. CMS 35±5 ml • kg-1; p=0.03) compared to non-CMS. There were no differences in ePASP between groups (non-CMS 32±9 vs. CMS 31±8 mmHg; p=0.6). A negative correlation was found between plasma renin activity and glomerular filtration rate in both groups (group: r=-0.66; p<0.01; non-CMS: r=-0.60; p=0.022; CMS: r=-0.63; p=0.049). A smaller plasma volume in Andeans with CMS may indicate an additional CMS maladaptation to high-altitude, causing potentially greater polycythemia and clinical symptoms.

Effect of beta-adrenoceptor blockade on renin-aldosterone and alpha-ANF during exercise at altitude

1989 ◽  
Vol 67 (1) ◽  
pp. 141-146 ◽  
Author(s):  
P. Bouissou ◽  
J. P. Richalet ◽  
F. X. Galen ◽  
M. Lartigue ◽  
P. Larmignat ◽  
...  
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Acute Mountain Sickness ◽  
Plasma Renin ◽  
Barometric Pressure ◽  
Suppressive Effect ◽  
Beta Blockade ◽  
Plasma Norepinephrine ◽  
Plasma Aldosterone Concentration ◽  
Ergometer Exercise

The renin-aldosterone system may be depressed in subjects exercising at high altitude, thereby preventing excessive angiotensin I (ANG I) and aldosterone levels, which could favor the onset of acute mountain sickness. The role of beta-adrenoceptors in hormonal responses to hypoxia was investigated in 12 subjects treated with a nonselective beta-blocker, pindolol. The subjects performed a standardized maximal bicycle ergometer exercise with (P) and without (C) acute pindolol treatment (15 mg/day) at sea level, as well as during a 5-day period at high altitude (4,350 m, barometric pressure 450 mmHg). During sea-level exercise, pindolol caused a reduction in plasma renin activity (PRA, 2.83 +/- 0.35 vs. 5.13 +/- 0.7 ng ANG I.ml-1.h-1, P less than 0.01), an increase in plasma alpha-atrial natriuretic factor (alpha-ANF) level (23.1 +/- 2.9 (P) vs. 10.4 +/- 1.5 (C) pmol/1, P less than 0.01), and no change in plasma aldosterone concentration [0.50 +/- 0.04 (P) vs. 0.53 +/- 0.03 (C) nmol/1]. Compared with sea-level values, PRA (3.45 +/- 0.7 ng ANG I.ml-1.h-1) and PA (0.39 +/- 0.03 nmol/1) were significantly lower (P less than 0.05) during exercise at high altitude. alpha-ANF was not affected by hypoxia. When beta-blockade was achieved at high altitude, exercise-induced elevation in PRA was completely abolished, but no additional decline in PA occurred. Plasma norepinephrine and epinephrine concentrations tended to be lower during maximal exercise at altitude; however, these differences were not statistically significant. Our results provide further evidence that hypoxia has a suppressive effect on the renin-aldosterone system. However, beta-adrenergic mechanisms do not appear to be responsible for inhibition of renin secretion at high altitude.

Altitude-induced erythrocytic 2,3-DPG and hemoglobin changes in rats of various ages

1975 ◽  
Vol 39 (2) ◽  
pp. 258-261 ◽  
Author(s):  
L. G. Martin ◽  
J. M. Connors ◽  
J. J. McGrath ◽  
J. Freeman
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Age Groups ◽  
Altitude Exposure ◽  
Simulated High Altitude ◽  
Erythropoietic Response ◽  
2,3 Dpg

Rats of various ages (2, 12, 24, and 40 mo of age) were exposed for 4 wk to either a simulated high altitude of 23,000 ft or to a Peoria, Ill., altitude of 650 ft above sea level. Hematocrit ratios, hemoglobin, and erythrocytic 2,3-diphospho-glycerate (2,3-DPG) concentrations were measured. Hematocrit and hemoglobin determinations revealed a decrease in erythrocytic content with increasing age, and the augmented erythropoietic response was seen in all age groups of animals as a result of altitude exposure. The maximal erythrocytic content of hemoglobin in the 40-mo-old animals was significantly lower than that of all other age groups. Erythrocytic 2,3-DPG levels were significantly changed by aging alone. In the 40-mo-old group there was a 35% increase over the next highest sea-level value. However, while erythrocytic 2,3-DPG content increased significantly in all other age groups following altitude exposure, it decreased 46% in the 40-mo-old group.

scholarly journals Effects of baseline heart rate at sea level on cardiac responses to high-altitude exposure

2020 ◽  
Vol 36 (5) ◽  
pp. 799-810
Author(s):  
Jingdu Tian ◽  
Chuan Liu ◽  
Yuanqi Yang ◽  
Shiyong Yu ◽  
Jie Yang ◽  
...  
Keyword(s):  
Heart Rate ◽  
High Altitude ◽  
Sea Level ◽  
Baseline Heart Rate ◽  
Altitude Exposure ◽  
Cardiac Responses

Effects of high altitude and water deprivation on arginine vasopressin release in men

2004 ◽  
Vol 286 (1) ◽  
pp. E20-E24 ◽  
Author(s):  
C. M. Maresh ◽  
W. J. Kraemer ◽  
D. A. Judelson ◽  
J. L. VanHeest ◽  
L. Trad ◽  
...  
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Arginine Vasopressin ◽  
Water Deprivation ◽  
Urine Volume ◽  
Plasma Osmolality ◽  
Vasopressin Release ◽  
Altitude Exposure ◽  
Blood Pressures ◽  
Healthy Males

High-altitude exposure changes the distribution of body water and electrolytes. Arginine vasopressin (AVP) may influence these alterations. The purpose of this study was to examine the effect of a 24-h water deprivation trial (WDT) on AVP release after differing altitude exposures. Seven healthy males (age 22 ± 1 yr, height 176 ± 2 cm, mass 75.3 ± 1.8 kg) completed three WDTs: at sea level (SL), after acute altitude exposure (2 days) to 4,300 m (AA), and after prolonged altitude exposure (20 days) to 4,300 m (PA). Body mass, standing and supine blood pressures, plasma osmolality (Posm), and plasma AVP (PAVP) were measured at 0, 12, 16, and 24 h of each WDT. Urine volume was measured at each void throughout testing. Baseline Posm increased from SL to altitude (SL 291.7 ± 0.8 mosmol/kgH2O, AA 299.6 ± 2.2 mosmol/kgH2O, PA 302.3 ± 1.5 mosmol/kgH2O, P < 0.05); however, baseline PAVP measurements were similar. Despite similar Posm values, the maximal PAVP response during the WDT (at 16 h) was greater at altitude than at SL (SL 1.7 ± 0.5 pg/ml, AA 6.4 ± 0.7 pg/ml, PA 8.7 ± 0.9 pg/ml, P < 0.05). In conclusion, hypoxia appeared to alter AVP regulation by raising the osmotic threshold and increasing AVP responsiveness above that threshold.

scholarly journals Cognitive and psychomotor responses to high-altitude exposure in sea level and high-altitude residents of Ecuador

2015 ◽  
Vol 34 (1) ◽  
Author(s):  
John E Davis ◽  
Dale R Wagner ◽  
Nathan Garvin ◽  
David Moilanen ◽  
Jessica Thorington ◽  
...  
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Altitude Exposure

Interleukin-6 response to exercise and high-altitude exposure: influence of α-adrenergic blockade

2001 ◽  
Vol 91 (5) ◽  
pp. 2143-2149 ◽  
Author(s):  
Robert S. Mazzeo ◽  
Danielle Donovan ◽  
Monika Fleshner ◽  
Gail E. Butterfield ◽  
Stacy Zamudio ◽  
...  
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Interleukin 6 ◽  
Moderate Intensity ◽  
Adrenergic Blockade ◽  
Moderate Intensity Exercise ◽  
Exercise Tests ◽  
Altitude Exposure ◽  
Excretion Rates ◽  
Response To Exercise

Interleukin-6 (IL-6), an important cytokine involved in a number of biological processes, is consistently elevated during periods of stress. The mechanisms responsible for the induction of IL-6 under these conditions remain uncertain. This study examined the effect of α-adrenergic blockade on the IL-6 response to acute and chronic high-altitude exposure in women both at rest and during exercise. Sixteen healthy, eumenorrheic women (aged 23.2 ± 1.4 yr) participated in the study. Subjects received either α-adrenergic blockade (prazosin, 3 mg/day) or a placebo in a double-blinded, randomized fashion. Subjects participated in submaximal exercise tests at sea level and on days 1 and 12 at altitude (4,300 m). Resting plasma and 24-h urine samples were collected throughout the duration of the study. At sea level, no differences were found at rest for plasma IL-6 between groups (1.5 ± 0.2 and 1.2 ± 0.3 pg/ml for placebo and blocked groups, respectively). On acute ascent to altitude, IL-6 levels increased significantly in both groups compared with sea-level values (57 and 84% for placebo and blocked groups, respectively). After 12 days of acclimatization, IL-6 levels remained elevated for placebo subjects; however, they returned to sea-level values in the blocked group. α-Adrenergic blockade significantly lowered the IL-6 response to exercise both at sea level (46%) and at altitude (42%) compared with placebo. A significant correlation ( P = 0.004) between resting IL-6 and urinary norepinephrine excretion rates was found over the course of time while at altitude. In conclusion, the results indicate a role for α-adrenergic regulation of the IL-6 response to the stress of both short-term moderate-intensity exercise and hypoxia.

scholarly journals Pulmonary embolism, frostbite and high-altitude retinopathy – a combination of life- and sight-threatening vascular complications at high altitude

2018 ◽  
Vol 64 (1) ◽  
pp. 30-34
Author(s):  
Shahzaib Rehan ◽  
Harvey J Pynn ◽  
Ian Williams ◽  
Daniel S Morris
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Vascular System ◽  
Vascular Complications ◽  
Pleuritic Chest Pain ◽  
Mount Everest ◽  
Pulmonary Angiogram ◽  
Adverse Weather ◽  
Ct Pulmonary Angiogram ◽  
Retinal Haemorrhages

The effects of high altitude on the human vascular system are well described. This case demonstrates an interesting combination of vascular complications at high altitude which were both life- and sight-threatening. In May 2017, during an attempt on Mount Everest, a 58-year-old man was forced to descend from 8000 m because of adverse weather. He suffered significant frostbite of his right hand, later requiring termination of the distal phalanx of one of the affected digits. He also experienced increasing breathlessness and went on to develop pleuritic chest pain. A CT pulmonary angiogram performed upon return to sea level revealed multiple small sub-segmental pulmonary emboli. He was anticoagulated for three months and made a full recovery. The patient also reported visual loss in the left eye and on ophthalmic examination was found to have multiple retinal haemorrhages including a left macular haemorrhage, consistent with high altitude retinopathy. The retinal haemorrhages settled with conservative management. The vascular complications suffered by this patient demonstrate the potentially fatal changes that can occur at altitude. They also serve to act as a reminder for physicians, even at sea level of the potential complications in patients returning from high altitude.

Arterial catecholamine responses during exercise with acute and chronic high-altitude exposure

1991 ◽  
Vol 261 (4) ◽  
pp. E419-E424 ◽  
Author(s):  
R. S. Mazzeo ◽  
P. R. Bender ◽  
G. A. Brooks ◽  
G. E. Butterfield ◽  
B. M. Groves ◽  
...  
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Neural Activity ◽  
Chronic Exposure ◽  
Physiological Responses ◽  
Submaximal Exercise ◽  
Altitude Exposure ◽  
Acute And Chronic Exposure ◽  
Over Time ◽  
Catecholamine Levels

Exercise at high altitude is a stress that activates the sympathoadrenal systems, which could affect responses to acute altitude exposure and promote adaptations during chronic altitude exposure. However, catecholamine levels are not clearly described over time at high altitude. In seven male volunteers (23 yr, 72 kg), resting arterial norepinephrine concentrations (ng/ml) on arrival at Pikes Peak (0.338 +/- 0.041) decreased compared with sea-level values (0.525 +/- 0.034) but increased to above sea-level values after 21 days at 4,300 m (0.798 +/- 0.052). Furthermore, during 45 min of constant submaximal exercise, values were similar at sea level (1.670 +/- 0.221) and on acute exposure to 4,300 m (2.123 +/- 0.086) but increased after 21 days of chronic exposure (2.693 +/- 0.216). By contrast, resting arterial epinephrine values (ng/ml) during acute and chronic exposure (0.708 +/- 0.033 vs. 0.448 +/- 0.026) both exceeded those of sea level (0.356 +/- 0.020). During exercise values on arrival were greater than at sea level (0.921 +/- 0.024 vs. 0.397 +/- 0.035) but fell to 0.612 +/- 0.025 ng/ml after 21 days. Exercise norepinephrine levels were related to systemic vascular resistance measurements (r = 0.93), whereas epinephrine levels were related to circulating lactate (r = 0.95). We conclude that during exercise at altitude there is a dissociation between norepinephrine, an indicator of sympathetic neural activity, and epinephrine, an indicator of adrenal medullary response. These actions may account for different metabolic and physiological responses to acute vs. chronic altitude exposure.

Aldosterone dynamics during graded exercise at sea level and high altitude

1975 ◽  
Vol 39 (1) ◽  
pp. 18-22 ◽  
Author(s):  
J. T. Maher ◽  
L. G. Jones ◽  
L. H. Hartley ◽  
G. H. Williams ◽  
L. I. Rose
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Renin Angiotensin System ◽  
O2 Uptake ◽  
Bicycle Exercise ◽  
Hormonal Responses ◽  
Angiotensin System ◽  
Altitude Exposure ◽  
Graded Exercise ◽  
Low Altitude

Hormonal responses to graded exercise of eight low altitude residents were examined at sea level (SL) and after 1 (acute) and 11 (chronic) days at 4,300 m (HA). Caloric, water, and electrolyte intakes were controlled, as were temperature and humidity. Blood was sampled at rest and during light and moderate upright bicycle exercise (20 min at 40% and 75% of maximal O2 uptake, respectively). Mean VO2 max at HA was 27% lower than at SL. Resting plasma levels of aldosterone (Aldo), renin, and angiotensin II (A II) were significantly lower (P smaller than 0.05) on day 1 at HA compared to SL, but returned to SL values by day 11. Plasma cortisol values at rest were similar at SL and HA and were not significantly altered by light or moderate exercise. Renin, A II, and Aldo rose progressively with increasing workload in each environment. With acute HA, renin and Aldo were lower than at either SL or chronic HA. The chronic HA levels tended to approximate SL findings, implying adaptation. The data suggest that aldosterone is predominantly under the control of the renin-angiotensin system during graded exercise at sea level and that the response of this system is altered on acute high-altitude exposure.

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