Chronic and Intermittent Hypoxia Induce Different Degrees of Myocardial Tolerance to Hypoxia-Induced Dysfunction

Milano, Giuseppina; Corno, Antonio F.; Lippa, Silvio; Segesser, Ludwig Karl von; Samaja, Michele

doi:10.1177/153537020222700604

Cited by 59 publications

(72 citation statements)

References 36 publications

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“…On the other hand, it is known that training in hypoxia and in normoxia reduced the circulating concentration of free fatty acids, total cholesterol and HDL cholesterol. However, it did not reduce the levels of homocysteine, an acidic molecule implicated in heart disease [98].…”

Section: Intermittent Hypoxic Training (Iht)mentioning

confidence: 84%

Usefulness of combining intermittent hypoxia and physical exercise in the treatment of obesity

Urdampilleta¹,

González‐Muniesa

Portillo³

et al. 2011

J Physiol Biochem

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SummaryObesity is an important public health problem worldwide and is a major risk factor for a number of chronic diseases such as type 2 diabetes, adverse cardiovascular events and metabolic syndrome related features. Different treatments have been applied to tackle body fat accumulation and its associated clinical manifestations. Often, relevant weight loss is achieved during the first six months under different dietary treatments. From this point, a plateau is reached, and a gradual recovery of the lost weight may occur.Therefore, new research approaches are being investigated to assure weight maintenance.Pioneering investigations have reported that oxygen variations in organic systems may produce changes in body composition. Possible applications of intermittent hypoxia to promote health and in various pathophysiological states have been reported.The hypoxic stimulus in addition to diet and exercise can be an interesting approach to lose weight, by inducing higher basal noradrenalin levels and other metabolic changes whose mechanisms are still unclear. Indeed, hypoxic situations increase the diameter of arterioles, produce peripheral vasodilatation and decrease arterial blood pressure. Furthermore, hypoxic training increases the activity of glycolytic enzymes, enhancing the number of mitochondria and glucose transporter GLUT-4 levels as well as improving insulin sensitivity. Moreover, hypoxia increases blood serotonin, decreases leptin levels while appetite is suppressed. These observations allow considering the hypothesis that intermittent hypoxia induces fat loss and may ameliorate cardiovascular health, which might be of interest for the treatment of obesity. This new strategy may be useful and practical for clinical applications in obese patients.Key Words: obesity, body weight loss, intermittent hypoxia, treatment. 1. Obesity: Prevalence, causes and complicationsObesity is an important public health problem in most countries [63], which is characterized by an excess of body fat, when amounting values higher than 20% in men and 30% in adult women [20,66].The World Health Organization (2009) warns that there are over 400 million obese adults, and that the situation will worsen in the future.The main etiological factors causing excess body weight for height are assigned to overeating and low physical activity, which lead to a positive energy balance, and result in a body fat increase [91]. Furthermore, there are other causes such as the genetic component, the distribution of energy intake throughout the day, the dietary composition of macronutrients, sleep rest, endocrine disruptions or the individual ability to oxidize energy substrates [26,70,93]. Thus, obesity is a chronic multifactorial disease resulting from the interaction between genotype, environment and physical activity patterns [14,91,95].Obesity is considered one of the major risk factors in the onset of associated chronic diseases, such as hypercholesterolemia, type II diabetes (T2D), cardiovascular disorders and metabolic syndrome features [1...

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Section: Intermittent Hypoxic Training (Iht)mentioning

confidence: 84%

Usefulness of combining intermittent hypoxia and physical exercise in the treatment of obesity

Urdampilleta¹,

González‐Muniesa

Portillo³

et al. 2011

J Physiol Biochem

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“…This issue is important because the half-life of HIF-1␣ in reoxygenated cell cultures is as short as few minutes (22,23). In addition, certain phenotypes produced by CH are profoundly affected by even short reoxygenation episodes (19,(24)(25)(26). The selected experimental protocol thus represents a model for CH that may arise either from physiological situations as high altitude and airline flights or pathological conditions as congenital heart disease, anemia, carbon monoxide poisoning, or chronic lung diseases.…”

Section: Discussionmentioning

confidence: 99%

“…In a model in which rats are exposed to normobaric CH for 15 days, we observed marked deterioration of myocardial protection (19) and sustained apoptosis in a number of organs (20). Although plasma Epo was not measured, an increase in blood Hb by Ͼ70% indicates a substantial Epo stimulation.…”

mentioning

confidence: 81%

Carbamylated erythropoietin ameliorates the metabolic stress induced in vivo by severe chronic hypoxia

Fantacci

Bianciardi

Caretti

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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Ischemia and chronic hypoxia (CH) trigger a variety of adverse effects arising from metabolic stress that injures cells. In response to reduced O 2, hypoxia-inducible factor 1␣ (HIF-1␣) activates erythropoietin (Epo) as well as many other target genes that counteract the effects of O 2 deficiency. Epo produced by the kidney stimulates erythrocyte production, leading to decreased HIF-1␣ production by improved tissue O 2 delivery. However, Epo is produced by many other tissues, and it is currently unclear to what extent, if any, locally produced Epo modulates HIF-1␣ expression. Derivatives of Epo that possess tissue-protective activities but do not stimulate erythropoiesis [e.g., carbamylated Epo (CEpo)] are useful tools with which to determine whether exogenous Epo modulates HIF-1␣ in the absence of changes in hemoglobin concentration. We compared the effects of CH (6.5% O 2 for 10 days) with or without CEpo administered by daily s.c. injection (10 g͞kg of body weight). CEpo administration did not alter the survival rate, weight loss, or increased hemoglobin concentration associated with CH. Therefore, CEpo does not directly suppress HIF-mediated erythropoiesis. CEpo does, however, prevent CH-induced neuronal increases of HIF-1␣ and Epo receptor-associated immunoreactivity (a measure of stress) while reducing the apoptotic index. In contrast, the myocardium did not exhibit increased HIF-1␣ expression during CH, although CEpo did reduce the apoptotic index. These observations therefore demonstrate that CEpo administration reduces the metabolic stress caused by severe CH, resulting in improved cellular survival independent of erythrocyte production.apoptosis ͉ brain ͉ hypoxia-inducible factor 1␣ ͉ heart ͉ Epo receptor

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“…Twenty-seven 5-week-old male rats were divided into three different groups (Milano et al 2002). Normoxic rats (n=8) breathed room air (FiO 2 =0.21), whereas 19 rats were exposed for 2 weeks to a normobaric hypoxic atmosphere (FiO 2 =0.10).…”

Section: Animals and Experimental Proceduresmentioning

confidence: 99%

Cellular distribution of Hsp70 expression in rat skeletal muscles. Effects of moderate exercise training and chronic hypoxia

Tarricone¹,

Scapin²,

Vitadello³

et al. 2008

Cell Stress and Chaperones

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Rat hindlimb muscles constitutively express the inducible heat shock protein 72 (Hsp70), apparently in proportion to the slow myosin content. Since it remains controversial whether chronic Hsp70 expression reflects the overimposed stress, we investigated Hsp70 cellular distribution in fast muscles of the posterior rat hindlimb after (1) mild exercise training (up to 30 m/min treadmill run for 1 h/day), which induces a remodeling in fast fiber composition, or (2) prolonged exposure to normobaric hypoxia (10%O 2 ), which does not affect fiber-type composition. Both conditions increased significantly protein Hsp70 levels in the skeletal muscle. Immunohistochemistry showed the labeling for Hsp70 in subsets of both slow/ type 1 and fast/type 2A myofibers of control, sedentary, and normoxic rats. Endurance training increased about threefold the percentage of Hsp70-positive myofibers (P<0.001), and changed the distribution of Hsp70 immunoreactivity, which involved a larger subset of both type 2A and intermediate type 2A/2X myofibers (P<0.001) and vascular smooth muscle cells. Hypoxia induced Hsp70 immunoreactivity in smooth muscle cells of veins and did not increase the percentage of Hsp70-positive myofibers; however, sustained exposure to hypoxia affected the distribution of Hsp70 immunoreactivity, which appeared detectable in a very small subset of type 2A fibers, whereas it concentrated in type 1 myofibers (P<0.05) together with the labeling for heme-oxygenase isoform 1, a marker of oxidative stress. Therefore, the chronic induction of Hsp70 expression in rat skeletal muscles is not obligatory related to the slow fiber phenotype but reveals the occurrence of a stress response.

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Chronic and Intermittent Hypoxia Induce Different Degrees of Myocardial Tolerance to Hypoxia-Induced Dysfunction

Cited by 59 publications

References 36 publications

Usefulness of combining intermittent hypoxia and physical exercise in the treatment of obesity

Usefulness of combining intermittent hypoxia and physical exercise in the treatment of obesity

Carbamylated erythropoietin ameliorates the metabolic stress induced in vivo by severe chronic hypoxia

Cellular distribution of Hsp70 expression in rat skeletal muscles. Effects of moderate exercise training and chronic hypoxia

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