Elevated pulmonary artery pressure among Amhara highlanders in Ethiopia

Hoit, Brian D.; Dalton, Nancy D.; Gebremedhin, Amha; Janocha, Allison J.; Zimmerman, Peter A.; Zimmerman, Allison M.; Erzurum, Serpil C.; Beall, Cynthia M.

doi:10.1002/ajhb.21130

Cited by 42 publications

(47 citation statements)

References 45 publications

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“…This is in contrast to histological findings in Andeans whose pulmonary artery structure is indicative of pulmonary hypertension (Arias-Stella and Saldana, 1963;Heath et al, 1981). In Ethiopians, the pulmonary vascular response to hypoxia includes a rise in pulmonary pressure but not resistance, which may be attributed to increased blood flow (Hoit et al, 2011).…”

Section: Oxygen Saturation Binding Affinities In Highland Groupscontrasting

confidence: 52%

Altitude Adaptation: A Glimpse Through Various Lenses

Simonson

2015

High Altitude Medicine & Biology

137

141

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Simonson, Tatum S. Altitude adaptation: A glimpse through various lenses. High Alt Med Biol 16:125-137, 2015.-Recent availability of genome-wide data from highland populations has enabled the identification of adaptive genomic signals. Some of the genomic signals reported thus far among Tibetan, Andean, and Ethiopian are the same, while others appear unique to each population. These genomic findings parallel observations conveyed by decades of physiological research: different continental populations, resident at high altitude for hundreds of generations, exhibit a distinct composite of traits at altitude. The most commonly reported signatures of selection emanate from genomic segments containing hypoxia-inducible factor (HIF) pathway genes. Corroborative evidence for adaptive significance stems from associations between putatively adaptive gene copies and sea-level ranges of hemoglobin concentration in Tibetan and Amhara Ethiopians, birth weights and metabolic factors in Andeans and Tibetans, maternal uterine artery diameter in Andeans, and protection from chronic mountain sickness in Andean males at altitude. While limited reports provide mechanistic insights thus far, efforts to identify and link precise genetic variants to molecular, physiological, and developmental functions are underway, and progress on the genomics front continues to provide unprecedented movement towards these goals. This combination of multiple perspectives is necessary to maximize our understanding of orchestrated biological and evolutionary processes in native highland populations, which will advance our understanding of both adaptive and non-adaptive responses to hypoxia.

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Section: Oxygen Saturation Binding Affinities In Highland Groupscontrasting

confidence: 52%

Altitude Adaptation: A Glimpse Through Various Lenses

Simonson

2015

High Altitude Medicine & Biology

137

141

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“…Supporting our catheterization data, recent echocardiographic studies show lower P pa values in Sherpa highlanders than in acclimatized lowland controls. 74 Higher values in Amhara highlanders than in sea-level controls have also been observed in Ethiopia, 15 suggesting that the Tibetans' low P pa at high altitude may be unique. The factors responsible for the Tibetans' relative protection from pulmonary hypertension at high altitude are unknown.…”

Section: Discussionmentioning

confidence: 99%

Neonatal Oxygenation, Pulmonary Hypertension, and Evolutionary Adaptation to High Altitude (2013 Grover Conference series)

Niermeyer

Andrade-M²,

Vargas

et al. 2015

Pulm. circ.

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Andeans and Tibetans have less altitude reduction in birth weight than do shorter-resident groups, but only Tibetans are protected from pulmonary hypertension and chronic mountain sickness (CMS). We hypothesized that differences in neonatal oxygenation were involved, with arterial O 2 saturation (SaO 2 ) being highest in Tibetans, intermediate in Andeans, and lowest in Han or Europeans, and that improved oxygenation in Andeans relative to Europeans was accompanied by a greater postnatal decline in systolic pulmonary arterial pressures (P pa sys ). We studied 41 healthy (36 Andeans, 5 Europeans) and 9 sick infants at 3,600 m in Bolivia. The SaO 2 in healthy babies was highest at 6-24 hours of postnatal age and then declined, whereas sick babies showed the opposite pattern. Compared to that of 30 Tibetan or Han infants studied previously at 3,600 m, SaO 2 was higher in Tibetans than in Han or Andeans during wakefulness and active or quiet sleep. Tibetans, as well as Andeans, had higher values than Han while feeding. The SaO 2 's of healthy Andeans and Europeans were similar and, like those of Tibetans, remained at 85% or above, whereas Han values dipped below 70%. Andean and European P pa sys values were above sea-level norms and higher in sick than in healthy babies, but right heart pressure decreased across 4-6 months in all groups. We concluded that Tibetans had better neonatal oxygenation than Andeans at 3,600 m but that, counter to our hypothesis, neither was SaO 2 higher nor P pa lower in Andean than in European infants. Further, longitudinal studies in these 4 groups are warranted to determine whether neonatal oxygenation influences susceptibility to high-altitude pulmonary hypertension and CMS later in life.Keywords: Andean, cardiopulmonary transition, Ethiopian, European, genetic adaptation, Han, hypoxia, Tibet. Studies at high altitude have long provided a useful model for persons interested in the pulmonary circulation. [1][2][3][4] While pulmonary arterial pressures (P pa 's) are generally elevated at high altitude, there is considerable population variation in both P pa and pulmonary circulation-related disorders such as chronic mountain sickness (CMS; Fig. 1A) 11,36 and subacute infantile mountain sickness. 37 Specifically, directly measured P pa and hypoxic pulmonary vasoconstrictor responses are lowest in Tibetans, intermediate in Andeans, and highest in European-derived residents of Colorado (Fig. 1B). Recent estimates using echocardiography also suggest intermediate values in Ethiopians. 15 While multiple factors contribute to the etiology of CMS and no well-controlled comparative epidemiological studies exist, a reduced prevalence among Tibetans is consistent with the lower hemoglobin levels seen in Tibetans, relative to Andeans, in multiple reports. [38][39][40] Tibetans are also protected, relative to Han, from subacute infantile mountain sickness, a syndrome characterized by severe pulmonary hypertension in 4-6-month-old infants that has also been reported in European-derived popul...

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“…9.2 ), but without elevated pulmonary vascular resistance, as a consequence of high pulmonary blood fl ow [ 41 ].…”

Section: Adult Ha Nativesmentioning

confidence: 98%

Right Ventricle and High Altitude

Richalet

Pichon

2014

The Right Heart

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At high altitude, as hypoxia induces pulmonary vasoconstriction and increases ipulmonary arterial pressure, right ventricular (RV) function will be affected. The right ventricular function may be affected directly by the hypoxaemic challenge or indirectly through a pressure overload due, in turn to changes in the pulmonary circulation. Both animal and human studies show that moderate or transient hypoxia results in adaptive changes in right ventricle that are reversible with re-exposure to normoxic conditions and RV dysfunction is mainly due to mechanical overload from the pulmonary circulation. When hypoxia is more severe or more prolonged, it may directly impact ventricular diastolic or systolic function through mechanisms that remain to be unraveled. Chronic exposure to hypoxia in high-altitude natives suffering from Monge's disease may lead to RV hypertrophy, RV failure and overall cardiac failure. The adrenergic system may be involved, as well as HIF, PKC or phospholamban. More studies using the latest imaging technology should give us a better understanding of RV systolic and diastolic function in humans exposed to altitude hypoxia including acute, chronic or chronic intermittent hypoxia.

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Elevated pulmonary artery pressure among Amhara highlanders in Ethiopia

Cited by 42 publications

References 45 publications

Altitude Adaptation: A Glimpse Through Various Lenses

Altitude Adaptation: A Glimpse Through Various Lenses

Neonatal Oxygenation, Pulmonary Hypertension, and Evolutionary Adaptation to High Altitude (2013 Grover Conference series)

Right Ventricle and High Altitude

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