Extreme altitude induces divergent mass reduction of right and left ventricle in mountain climbers

Udjus, Camilla; Sjaastad, Ivar; Hjørnholm, Ulla; Tunestveit, Torbjørn K; Hoffmann, Pavel; Hinojosa, Alexis; Espe, Emil Knut Stenersen; Christensen, Geir; Skjønsberg, Ole Henning; Larsen, Karl-Otto; Rostrup, Morten

doi:10.14814/phy2.15184

Cited by 3 publications

(1 citation statement)

References 44 publications

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“…Udjus C et al found that the knockdown of caspase-1 reduced SMC proliferation in pulmonary arteries and improved PAH in mice via the caspase-1/IL-18/IL-6/STAT3 pathway. [44] In addition, a study by Zaheer A et al suggested [3] that GMF𝛽 could induce the production of IL-6, and IL-6 could induce the expression of POSTN in fibroblasts through activation of the STAT3 pathway and ultimately promote the proliferation of fibroblasts.…”

Section: Gmf𝜷 Regulates the Expression Of Postn Through Il-6-stat3 Pa...mentioning

confidence: 99%

Preliminary Mechanism of Glial Maturation Factor β on Pulmonary Vascular Remodeling in Pulmonary Arterial Hypertension

Li,

Shi,

Yan

et al. 2024

Advanced Biology

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Recent evidence suggests that glia maturation factor β (GMFβ) is important in the pathogenesis of pulmonary arterial hpertension (PAH), but the underlying mechanism is unknown. To clarify whether GMFβ can be involved in pulmonary vascular remodeling and to explore the role of the IL‐6‐STAT3 pathway in this process, the expression of GMFβ in PAH rats is examined and the expression of downstream molecules including periostin (POSTN) and interleukin‐6 (IL‐6) is measured using real‐time quantitative polymerase chain reaction (RT‐qPCR) and western blot analysis. The location and expression of POSTN is also tested in PAH rats using immunofluorescence. It is proved that GMFβ is upregulated in the lungs of PAH rats. Knockout GMFβ alleviated the MCT‐PAH by reducing right ventricular systolic pressure (RVSP), mean pulmonary arterial pressure (mPAP), and pulmonary vascular remodeling. Moreover, the inflammation of the pulmonary vasculature is ameliorated in PAH rats with GMFβ absent. In addition, the IL‐6‐STAT3 signaling pathway is activated in PAH; knockout GMFβ reduced POSTN and IL‐6 production by inhibiting the IL‐6‐STAT3 signaling pathway. Taken together, these findings suggest that knockout GMFβ ameliorates PAH in rats by inhibiting the IL‐6‐STAT3 signaling pathway.

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Section: Gmf𝜷 Regulates the Expression Of Postn Through Il-6-stat3 Pa...mentioning

confidence: 99%

Preliminary Mechanism of Glial Maturation Factor β on Pulmonary Vascular Remodeling in Pulmonary Arterial Hypertension

Li,

Shi,

Yan

et al. 2024

Advanced Biology

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Association of attenuated leptin signaling pathways with impaired cardiac function under prolonged high-altitude hypoxia

Wang,

Liu,

Sun

et al. 2024

Sci Rep

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Cardiovascular function and adipose metabolism were markedly influenced under high altitudes. However, the interplay between adipokines and heart under hypoxia remains to be elucidated. We aim to explore alterations of adipokines and underlying mechanisms in regulating cardiac function under high altitudes. We investigated the cardiopulmonary function and five adipokines in Antarctic expeditioners at Kunlun Station (4,087 m) for 20 days and established rats exposed to hypobaric hypoxia (5,000 m), simulating Kunlun Station. Antarctic expeditioners exhibited elevated heart rate, blood pressure, systemic vascular resistance, and decreased cardiac pumping function. Plasma creatine phosphokinase-MB (CK-MB) and platelet-endothelial cell adhesion molecule-1 (sPecam-1) increased, and leptin, resistin, and lipocalin-2 decreased. Plasma leptin significantly correlated with altered cardiac function indicators. Additionally, hypoxic rats manifested impaired left ventricular systolic and diastolic function, elevated plasma CK-MB and sPecam-1, and decreased plasma leptin. Chronic hypoxia for 14 days led to increased myocyte hypertrophy, fibrosis, apoptosis, and mitochondrial dysfunction, coupled with reduced protein levels of leptin signaling pathways in myocardial tissues. Cardiac transcriptome analysis revealed leptin was associated with downregulated genes involved in rhythm, Na+/K+ transport, and cell skeleton. In conclusion, chronic hypoxia significantly reduced leptin signaling pathways in cardiac tissues along with significant pathological changes, thus highlighting the pivotal role of leptin in regulation of cardiac function under high altitudes.

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Extreme altitude induces divergent mass reduction of right and left ventricle in mountain climbers

Udjus

Sjaastad

Hjørnholm

et al. 2022

Physiological Reports

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Mountain climbing at high altitude implies exposure to low levels of oxygen, low temperature, wind, physical and psychological stress, and nutritional insufficiencies. We examined whether right ventricular (RV) and left ventricular (LV) myocardial masses were reversibly altered by exposure to extreme altitude. Magnetic resonance imaging and echocardiography of the heart, dual x‐ray absorptiometry scan of body composition, and blood samples were obtained from ten mountain climbers before departure to Mount Everest or Dhaulagiri (baseline), 13.5 ± 1.5 days after peaking the mountain (post‐hypoxia), and six weeks and six months after expeditions exceeding 8000 meters above sea level. RV mass was unaltered after extreme altitude, in contrast to a reduction in LV mass by 11.8 ± 3.4 g post‐hypoxia ( p = 0.001). The reduction in LV mass correlated with a reduction in skeletal muscle mass. After six weeks, LV myocardial mass was restored to baseline values. Extreme altitude induced a reduction in LV end‐diastolic volume (20.8 ± 7.7 ml, p = 0.011) and reduced E’, indicating diastolic dysfunction, which were restored after six weeks follow‐up. Elevated circulating interleukin‐18 after extreme altitude compared to follow‐up levels, might have contributed to reduced muscle mass and diastolic dysfunction. In conclusion, the mass of the RV, possibly exposed to elevated afterload, was not changed after extreme altitude, whereas LV mass was reduced. The reduction in LV mass correlated with reduced skeletal muscle mass, indicating a common denominator, and elevated circulating interleukin‐18 might be a mechanism for reduced muscle mass after extreme altitude.

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Extreme altitude induces divergent mass reduction of right and left ventricle in mountain climbers

Cited by 3 publications

References 44 publications

Preliminary Mechanism of Glial Maturation Factor β on Pulmonary Vascular Remodeling in Pulmonary Arterial Hypertension

Preliminary Mechanism of Glial Maturation Factor β on Pulmonary Vascular Remodeling in Pulmonary Arterial Hypertension

Association of attenuated leptin signaling pathways with impaired cardiac function under prolonged high-altitude hypoxia

Extreme altitude induces divergent mass reduction of right and left ventricle in mountain climbers

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