Effects of acidosis and alkalosis on hypoxic pulmonary vasoconstriction in dogs

Brimioulle, Serge; Lejeune, Philippe; Vachiéry, Jean‐Luc; Leeman, Marc; Mélot, Christian; Naeije, Robert

doi:10.1152/ajpheart.1990.258.2.h347

Cited by 61 publications

(58 citation statements)

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“…Supporting this hypothesis, manipulating pH i by inducing intracellular acidification inhibited, 61 while intracellular alkalinization enhanced, 61,84 HPV. However, these reports stand in contrast to other studies, in which HPV was attenuated by hypocapnic alkalosis [85][86][87][88][89] and enhanced by hypercapnic acidosis. [88][89][90] It should be noted, however, that the magnitude of the change in pH i under these conditions was not measured and could vary considerably from that in experiments where pH i was manipulated directly.…”

Section: Role Of Nhe1 In Acute Hypoxic Pulmonary Vasoconstriction (Hpv)contrasting

confidence: 95%

Na⁺/H⁺ Exchange and Hypoxic Pulmonary Hypertension

Huetsch

Shimoda

2015

Pulm. circ.

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Intracellular pH (pH i ) homeostasis is key to the functioning of vascular smooth muscle cells, including pulmonary artery smooth muscle cells (PASMCs). Sodium-hydrogen exchange (NHE) is an important contributor to pH i control in PASMCs. In this review, we examine the role of NHE in PASMC function, in both physiologic and pathologic conditions. In particular, we focus on the contribution of NHE to the PASMC response to hypoxia, considering both acute hypoxic pulmonary vasoconstriction and the development of pulmonary vascular remodeling and pulmonary hypertension in response to chronic hypoxia. Hypoxic pulmonary hypertension remains a disease with limited therapeutic options. Thus, this review explores past efforts at disrupting NHE signaling and discusses the therapeutic potential that such efforts may have in the field of pulmonary hypertension.

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Section: Role Of Nhe1 In Acute Hypoxic Pulmonary Vasoconstriction (Hpv)contrasting

confidence: 95%

Na⁺/H⁺ Exchange and Hypoxic Pulmonary Hypertension

Huetsch

Shimoda

2015

Pulm. circ.

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“…The rheological properties of dextran and a low haematocrit may explain the impairment of HPV in the dextran group. Metabolic situations, such as acidosis or alkalosis, could therefore modify the HPV response [22]. However, in the current study, no significant variation of pH and Pa,CO 2 were observed in the dextran group.…”

Section: Discussioncontrasting

confidence: 75%

The effect of hypertonic saline dextran solutions on hypoxic pulmonary vasoconstriction in anaesthetised piglets

Bellezza¹,

Kerbaul²,

Roussel³

et al. 2002

European Respiratory Journal

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The effect of hypertonic saline dextran solutions on hypoxic pulmonary vasoconstriction in anaesthetised piglets. M. Bellezza, F. Kerbaul, L. Roussel, M. Imbert, C. Guidon. #ERS Journals Ltd 2002. ABSTRACT: Hypoxic pulmonary vasoconstriction (HPV) is a regulatory mechanism by which blood is diverted from poorly ventilated to better ventilated areas of the lung. The aim of the present study was to assess the extent to which hypertonic saline dextran and dextran solutions modify the magnitude of HPV during isovolumic haemodilution in intact acutely instrumented piglets.Eighteen large white piglets were anesthetised and assigned to two groups. Mean pulmonary arterial pressure (PAP) and cardiac output (Q), systemic arterial pressure and left arterial pressure (LAP) were measured. A decrease in Q was obtained by reducing venous return. This enabled measurement of transpulmonary pressures (mean PAP minus LAP) at four levels of Q in hyperoxia (inspiratory oxygen fraction (Fi,O 2 )=0.4), then in hypoxia (Fi,O 2= 0.1) in the two groups before blood soustraction (10 mL?kg -1 ) and after loading with sodium chloride (NaCl) 7.5% and dextran 6% or with dextran 6% alone. Dextran alone led to a decrease in mean PAP-LAP/Q values, and NaCl with dextran was associated with a significant shift of mean PAP-LAP/Q plots to higher pressures in hypoxia.Hypertonic saline dextran solution, as replacement fluid in isovolaemic haemodilution increased the magnitude of hypoxic pulmonary vasoconstriction, whereas dextran solution reduced it. Fluid expanders are usually used for the resuscitation of intraoperative hypovolaemia or haemorragia. They act on different parts of the cardiovascular system, mainly the heart and vascular resistances. Therefore, the vascular resistance response differs with the solution used and the vascular bed of the organ studied [1,2].Hypertonic saline solution (sodium chloride (NaCl) 7.5%) with dextran 6% has been shown to increase volaemia ten-times more than dextran 6% by an osmotic effect (transfer of water from the interstitial to vascular space), this, in turn, increases cardiac output (Q) and decreases systemic vascular resistance [3,4]. However, the effect of this hypertonic saline and dextran solution on pulmonary circulation remains unknown. Dextran used alone can also reduce pulmonary vascular resistance (PVR) resulting in a reduction of blood viscosity.Therefore, the effect of these two different plasma expanders on pulmonary vascular circulation was studied, focusing on the hypoxic pulmonary vascular response using pressure (P)/Q relationships in intact anaesthetised piglets submitted to normovolaemic haemodilution. It was hypothesised that these two different plasma expanders would have different effects on hypoxic pulmonary vasoconstriction (HPV), and thereby modify gas exchange. Piglets were chosen because they exhibit the greatest pulmonary vasoconstriction response to hypoxia [5]. In this study, pulmonary haemodynamics were evaluated by multipoint P/Q (mean pulmonary arterial pressure (PAP)-LAP/Q) ...

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“…Many investigators have attempted to assess the effects of HA or IA on vasoconstriction in the pulmonary circulation, mainly based on measurements of Ppa changes [16][17][18][19]. In the present study, however, a real-time confocal laser scanning luminescence optical microscope, which allows clear discrimination of individual microvessels from their neighbours, was applied [8].…”

Section: Critique Of Methodsmentioning

confidence: 99%

NOS and COX isoforms and abnormal microvessel responses to CO2 and H+ in hyperoxia-injured lungs

Naoki¹,

Kudo²,

Suzuki³

et al. 2002

European Respiratory Journal

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The aim of the present study was to compare microvessel responses to hypercapnic and isocapnic acidosis in hyperoxia-injured lungs and to assess the role of constitutive and inducible forms of nitric oxide synthase (NOS) and cyclo-oxygenase (COX).Real-time confocal luminescence microscopy was used to measure changes in the diameter of acinar arterioles, venules and capillaries in response to stimulation with hypercapnic and isocapnic acidosis in isolated rat lungs injured by 90% oxygen exposure for 48 h. Observations were made with and without inhibition of constitutive (endothelial constitutive NOS (ecNOS) and COX-1) and inducible isoforms (iNOS and COX-2) of NOS and COX. Upregulation of NOS was assessed by measuring enzyme levels in lung homogenates by Western blot analysis and enhancement of the COX-related pathway was judged from perfusate concentrations of 6-ketoprostaglandin F 1a .ecNOS and COX-1, but not iNOS and COX-2, were upregulated in hyperoxiainjured lungs. The nitric oxide produced by ecNOS attenuated COX-1 activity in injured arterioles and venules, but carbon dioxide enhanced it, leading to paradoxical dilatation of these microvessels under hypercapnic conditions with ecNOS inhibition. Although a high hydrogen ion concentration was unnecessary for excitation of COX-1, venule constriction in response to H z was enhanced by COX-1 inhibition. Constitutive, but not inducible, isoforms of cyclo-oxygenase and nitric oxide synthase play an important role in abnormal microvessel responses to carbon dioxide and hydrogen ions in hyperoxia-injured lungs. Eur Respir J 2002; 20: 43-51.

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Effects of acidosis and alkalosis on hypoxic pulmonary vasoconstriction in dogs

Cited by 61 publications

References 0 publications

Na⁺/H⁺ Exchange and Hypoxic Pulmonary Hypertension

Na⁺/H⁺ Exchange and Hypoxic Pulmonary Hypertension

The effect of hypertonic saline dextran solutions on hypoxic pulmonary vasoconstriction in anaesthetised piglets

NOS and COX isoforms and abnormal microvessel responses to CO2 and H+ in hyperoxia-injured lungs

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Effects of acidosis and alkalosis on hypoxic pulmonary vasoconstriction in dogs

Cited by 61 publications

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Na+/H+ Exchange and Hypoxic Pulmonary Hypertension

Na+/H+ Exchange and Hypoxic Pulmonary Hypertension

The effect of hypertonic saline dextran solutions on hypoxic pulmonary vasoconstriction in anaesthetised piglets

NOS and COX isoforms and abnormal microvessel responses to CO2 and H+ in hyperoxia-injured lungs

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Na⁺/H⁺ Exchange and Hypoxic Pulmonary Hypertension

Na⁺/H⁺ Exchange and Hypoxic Pulmonary Hypertension