losartan-potassium and Pulmonary-Edema

Topics: Adaptation, Physiological; Altitude Sickness; Calcium; Chronic Disease; Endothelium, Vascular; Erythropoietin; Heart Failure; Hemodynamics; Humans; Hypertension, Pulmonary; Hypoxia; Muscle, Smooth; Pulmonary Edema; Vascular Diseases; Vascular Remodeling; Vasoconstriction

High-altitude pulmonary oedema (HAPE) is a potentially fatal condition affecting fit and previously well individuals at altitudes in excess of 3000 m. This article discusses the mechanisms of HAPE, considers the contribution of hypoxic pulmonary vasoconstriction and alterations in sodium transport to the pathological process. It discusses the various biochemical mediators such as nitric oxide (NO), endothelin-1 (ET-1), and the renin-angiotensin-aldosterone system (RAS) that may be involved and considers possible oxygen-sensing mechanisms involved in hypoxic adaptation such as hypoxia-inducible factor-1 (HIF-1). Those who have had HAPE once run an unpredictable but significant risk of recurrence; therefore, there may be a constitutional or genetic component in its aetiology. This paper considers the possible involvement of genes that may be involved in physiological adaptation to hypoxia (e.g., angiotensin-1 [AT(1)]-converting enzyme [ACE], tyrosine hydroxylase, serotonin transporter [5-HTT], and endothelial NO synthase [eNOS] genes). As yet, no formal association has been identified between an identified genetic polymorphism and HAPE, but genetic variation provides a possible mechanism to explain interindividual variation in response to hypoxia and enhanced or reduced performance at altitude.

Topics: Altitude Sickness; Animals; DNA-Binding Proteins; Erythropoietin; Humans; Hypoxia-Inducible Factor 1; Hypoxia-Inducible Factor 1, alpha Subunit; Nitric Oxide; Nitric Oxide Synthase; Nuclear Proteins; Polymorphism, Genetic; Pulmonary Edema; Renin-Angiotensin System; Transcription Factors

Anemia is common in patients with chronic heart failure and an independent predictor of poor prognosis. Chronic anemia leads to left ventricular (LV) hypertrophy and heart failure, but its molecular mechanisms remain largely unknown. We investigated the mechanisms, including the molecular signaling pathway, of cardiac remodeling induced by iron deficiency anemia (IDA). Weanling Sprague-Dawley rats were fed an iron-deficient diet for 20 wk to induce IDA, and the molecular mechanisms of cardiac remodeling were evaluated. The iron-deficient diet initially induced severe anemia, which resulted in LV hypertrophy and dilation with preserved systolic function associated with increased serum erythropoietin (Epo) concentration. Cardiac STAT3 phosphorylation and VEGF gene expression increased by 12 wk of IDA, causing angiogenesis in the heart. Thereafter, sustained IDA induced upregulation of cardiac hypoxia inducible factor-1alpha gene expression and maintained upregulation of cardiac VEGF gene expression and cardiac angiogenesis; however, sustained IDA promoted cardiac fibrosis and lung congestion, with decreased serum Epo concentration and cardiac STAT3 phosphorylation after 20 wk of IDA compared with 12 wk. Upregulation of serum Epo concentration and cardiac STAT3 phosphorylation is associated with a beneficial adaptive mechanism of anemia-induced cardiac hypertrophy, and later decreased levels of these molecules may be critical for the transition from adaptive cardiac hypertrophy to cardiac dysfunction in long-term anemia. Understanding the mechanism of cardiac maladaptation to anemia may lead to a new strategy for treatment of chronic heart failure with anemia.

Topics: Adaptation, Physiological; Anemia, Iron-Deficiency; Animals; Blood Pressure; Body Weight; Disease Models, Animal; Erythropoietin; Heart; Heart Failure; Heart Rate; Hypertrophy, Left Ventricular; Hypoxia-Inducible Factor 1, alpha Subunit; Iron; Kidney; Male; Myocardial Contraction; Myocardium; Neovascularization, Physiologic; Phosphorylation; Pulmonary Edema; Rats; Rats, Sprague-Dawley; Receptors, Erythropoietin; STAT3 Transcription Factor; Time Factors; Tumor Necrosis Factor-alpha; Vascular Endothelial Growth Factor A; Ventricular Function, Left; Ventricular Pressure; Ventricular Remodeling

Topics: Acclimatization; Adult; Altitude; Erythropoietin; Hematocrit; Humans; Hypoxia; Male; Pulmonary Edema; Time Factors

In order to investigate whether vascular endothelial growth factor (VEGF) and inflammatory pathways are activated during acute hypobaric hypoxia in subjects who are susceptible to high-altitude pulmonary oedema (HAPE-S), seven HAPE-S and five control subjects were exposed to simulated altitude corresponding to 4000 m in a hypobaric chamber for 1 day. Peripheral venous blood was taken at 450 m (Zürich level) and at 4000 m, and levels of erythropoietin (EPO), VEGF, interleukin-6 (IL-6) and the acute-phase proteins complement C3 (C3), alpha1-antitrypsin (alpha1AT), transferrin (Tf) and C-reactive protein (CRP) were measured. Peripheral arterial oxygen saturation (SaO2) was recorded. Chest radiography was performed before and immediately after the experiment. EPO increased during altitude exposure, correlating with SaO2, in both groups (r = -0.86, P < 0.001). Venous serum VEGF did not show any elevation despite a marked decrease in SaO2 in the HAPE-S subjects [mean (SD) HAPE-S: 69.6 (9.1)%; controls: 78.7 (5.2)%]. C3 and alpha1AT levels increased in HAPE-S during hypobaric hypoxia [from 0.94 (0.11) g/l to 1.07 (0.13) g/l, and from 1.16 (0.08) g/l to 1.49 (0.27) g/l, respectively; P < 0.05], but remained within the clinical reference ranges. No significant elevations of IL-6, Tf or CRP were observed in either group. The post-exposure chest radiography revealed no signs of oedema. We conclude that VEGF is not up-regulated in HAPE-S and thus does not seem to increase critically pulmonary vascular permeability during the 1st day at high altitude. Furthermore, our data provide evidence against a clinically relevant inflammation in the initial phase of exposure to hypoxia in HAPE-S, although C3 and alpha1AT are mildly induced.

Topics: Acute-Phase Proteins; Acute-Phase Reaction; Adult; Altitude; Atmospheric Pressure; Disease Susceptibility; Endothelial Growth Factors; Erythropoietin; Humans; Hypoxia; Lymphokines; Male; Middle Aged; Pulmonary Edema; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Reduced oxygen tension is regarded as the primary physiologic signal for the production of erythropoietin (EPO). There is little information available about early changes of EPO production in man due to severe hypoxia. The purpose of the present study was to examine the time course of EPO in serum of patients with acute cardiogenic pulmonary edema (ACPE). In 29 patients (seventy-five +/- six years, mean age +/- SEM) who were hospitalized within two hours after onset of symptoms of ACPE, serum EPO concentrations were monitored for up to seventy-two hours. At the moment of admission all patients showed significantly increased EPO concentrations of 121 +/- 64 mU/mL (mean +/- SEM) compared with a healthy population (15-35 mU/mL). Twenty-three patients who recovered within thirty minutes (group A) exhibited a quick return of their EPO serum levels to normal. The remaining 6 patients (group B) had a protracted clinical course and their EPO concentration showed a further increase up to the end of the observation period. The comparative monitoring of concentrations of alpha-1-proteinase inhibitor, antithrombin III, C-reactive protein, fibronectin, hapotoglobin, and transerrin in serum and plasma revealed no significant changes. Thus a major contribution of fluid shifts into or from the intravascular compartment to the observed changes in EPO concentration seems to be unlikely. The data suggest that the production and release of EPO in the kidneys due to altered oxygen delivery is a fast-responding mechanism.

Topics: Acute Disease; Aged; Aged, 80 and over; Blood Proteins; Cardiovascular Diseases; Erythropoietin; Female; Humans; Hypoxia; Kidney; Male; Pulmonary Edema