Hypoxia and the Heart

Moret, Pierre

doi:10.1016/b978-0-12-119402-4.50013-0

Cited by 9 publications

(7 citation statements)

References 154 publications

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“…No change was recorded in the LV part of the heart. These data confirm (15,28) and extend previous results by reporting a specific effect of chronic hypoxia on the RV and no age-related effect of chronic hypoxia on the RV NE content decrease and on the cardiac adrenergic response to hypoxia. The role of NE in cardiovascular hypertrophic remodeling has been reported (16).…”

Section: Changes In Whole Cell Potassium Current Densitysupporting

confidence: 93%

Effects of aging on the cardiac remodeling induced by chronic high-altitude hypoxia in rat

Chouabe¹,

Ricci²,

Amsellem³

et al. 2004

American Journal of Physiology-Heart and Circulatory Physiology

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Effects of chronic high-altitude hypoxia on the remodeling of right ventricle were examined in three age groups of rats: 2, 6, and 18 mo. The extent of right ventricular (RV) hypertrophy (RVH) showed an age-associated diminution. RV cell size and pericellular fibrosis showed a significant increase in the 2- and 6-mo-old exposed rats but not in the 18-mo-old exposed rats compared with control. A hyperplasic response was underscored in the three exposed age groups but appeared less pronounced in the 18-mo-old rats. A significant decrease in the transient outward potassium current (Ito) density was observed in RV cell only in the 2-mo-old exposed group compared with the control group. In the control group, there was a clear tendency for Ito density to decrease as a function of age. The sustained outward current density was modified neither by the hypoxia condition nor by the age. Neither the cytochrome c oxidase activity nor the heat shock protein 72 content in the RV was altered after hypoxic exposure regardless of age. The norepinephrine content in the RV was significantly decreased in each age group exposed to hypoxia when compared with their age-matched control group. Our findings indicate that the remodeling (at morphological and electrophysiological levels) induced by chronic hypoxia in the RV can be decreased by the natural aging process.

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Section: Changes In Whole Cell Potassium Current Densitysupporting

confidence: 93%

Effects of aging on the cardiac remodeling induced by chronic high-altitude hypoxia in rat

Chouabe¹,

Ricci²,

Amsellem³

et al. 2004

American Journal of Physiology-Heart and Circulatory Physiology

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“…In two cases, however, systemic hypoxia can be qualified as physiological: 1) the fetal myocardium that is adapted to hypoxia corresponding to an altitude of 8,000 m ("Mount Everest in utero") (202) and 2) the myocardium of subjects living permanently at high altitudes. In both situations, the myocardium is significantly more resistant to acute oxygen deficiency, but in populations living in lowlands, this property is lost soon after birth (72,137).…”

Section: A Definitionmentioning

confidence: 99%

“…In addition to such protective effects, adaptation to chronic hypoxia may also exert adverse influences on the cardiopulmonary system, including the development of pulmonary hypertension and right ventricular hypertrophy, which may result in congestive heart failure (for review, see Refs. 26,100,137,154,165).…”

Section: A Adaptation To Chronic Hypoxiamentioning

confidence: 99%

Development of Cardiac Sensitivity to Oxygen Deficiency: Comparative and Ontogenetic Aspects

Ošťádal

Ošťádalová

Dhalla

1999

Physiological Reviews

152

103

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Hypoxic states of the cardiovascular system are undoubtedly associated with the most frequent diseases of modern times. They originate as a result of disproportion between the amount of oxygen supplied to the cardiac cell and the amount actually required by the cell. The degree of hypoxic injury depends not only on the intensity and duration of the hypoxic stimulus, but also on the level of cardiac tolerance to oxygen deprivation. This variable changes significantly during phylogenetic and ontogenetic development. The heart of an adult poikilotherm is significantly more resistant as compared with that of the homeotherms. Similarly, the immature homeothermic heart is more resistant than the adult, possibly as a consequence of its greater capability for anaerobic glycolysis. Tolerance of the adult myocardium to oxygen deprivation may be increased by pharmacological intervention, adaptation to chronic hypoxia, or preconditioning. Because the immature heart is significantly more dependent on transsarcolemmal calcium entry to support contraction, the pharmacological protection achieved with drugs that interfere with calcium handling is markedly altered. Developing hearts demonstrated a greater sensitivity to calcium channel antagonists; a dose that induces only a small negative inotropic effect in adult rats stops the neonatal heart completely. Adaptation to chronic hypoxia results in similarly enhanced cardiac resistance in animals exposed to hypoxia either immediately after birth or in adulthood. Moreover, decreasing tolerance to ischemia during early postnatal life is counteracted by the development of endogenous protection; preconditioning failed to improve ischemic tolerance just after birth, but it developed during the early postnatal period. Basic knowledge of the possible improvements of immature heart tolerance to oxygen deprivation may contribute to the design of therapeutic strategies for both pediatric cardiology and cardiac surgery.

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“…The possible mechanisms involve, for example, an increased capacity for blood and tissue oxygen transport, neurohumoral regulations, and changes in cardiac metabolism. 14,15 According to Moret, 16 the protective effect includes an increased capacity of cardiac anaerobic metabolism, increased energy utilization capacity, and possibly selection of metabolic pathways or substrates with a higher energy efficiency that would decrease the oxygen requirements. This view is supported by our previous findings in chronically hypoxic rats, 17 in which both ventricles had a significantly increased capacity for glucose utilization (hexokinase), as well as for the synthesis and degradation of lactate (lactate dehydrogenase).…”

Section: Introductionmentioning

confidence: 99%

Activity of Cytochrome c Oxidase in the Right and Left Ventricular Myocardium of Male and Female Rats Exposed To Intermittent High Altitude Hypoxia^a

Stieglerová

Drahota

Houštěk

et al. 1999

Annals of the New York Academy of Sciences

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The aim of the present study was to compare the capacity of the oxidative metabolism (total activity of cytochrome c oxidase, COX) in the right and left ventricular myocardium of adult rats exposed to intermittent high altitude (IHA) hypoxia simulated in a barochamber (5,000 m, 8 h/day, 5 days/wk, for a total of 32 exposures). In male and female rats, IHA induced significant increases of the right ventricular (RV) weight and protein content, whereas left ventricular (LV) weight and protein content remained unaffected. Consequently, the RV/LV ratio in both sexes markedly increased. Similarly, IHA induced an increase of the total activity of COX in RV in both sexes. The specific activities of COX in homogenate as well as in isolated mitochondria were not changed in IHA-exposed animals, which indicates that the increase of total activity of COX is proportional to the increase of total protein content and RV weight.

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Hypoxia and the Heart

Cited by 9 publications

References 154 publications

Effects of aging on the cardiac remodeling induced by chronic high-altitude hypoxia in rat

Effects of aging on the cardiac remodeling induced by chronic high-altitude hypoxia in rat

Development of Cardiac Sensitivity to Oxygen Deficiency: Comparative and Ontogenetic Aspects

Activity of Cytochrome c Oxidase in the Right and Left Ventricular Myocardium of Male and Female Rats Exposed To Intermittent High Altitude Hypoxia^a

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Hypoxia and the Heart

Cited by 9 publications

References 154 publications

Effects of aging on the cardiac remodeling induced by chronic high-altitude hypoxia in rat

Effects of aging on the cardiac remodeling induced by chronic high-altitude hypoxia in rat

Development of Cardiac Sensitivity to Oxygen Deficiency: Comparative and Ontogenetic Aspects

Activity of Cytochrome c Oxidase in the Right and Left Ventricular Myocardium of Male and Female Rats Exposed To Intermittent High Altitude Hypoxiaa

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Activity of Cytochrome c Oxidase in the Right and Left Ventricular Myocardium of Male and Female Rats Exposed To Intermittent High Altitude Hypoxia^a