Hypoxic pulmonary vascular response can screen subclinical lifestyle disease in healthy population.

OBJECTIVE: Subclinical life style disease can cause endothelial dysfunction associated with perfusion abnormalities and reduced vascular compliance. Subclinical elevated beta type natriuretic peptide (BNP) has been associated with altered fluid shift from extra to intracellular space during acute hypoxia. Therefore we measured vascular response and BNP levels during acute hypoxia to study endothelial functions among healthy individuals. METHODS: Individuals were exposed to acute normobaric hypoxia of FiO2 = 0.15 for one hour in supine position and their pulmonary and systemic vascular response to hypoxia was compared. Individuals were divided into two groups based on either no response (Group 1) or rise in systolic pulmonary artery pressure to hypoxia (Group 2) and their BNP levels were compared. RESULTS: BNP was raised after hypoxia exposure in group 2 only from 18.52 ± 7 to 21.56 ± 10.82 picogram/ml, p < 0.05. Group 2 also showed an increase in mean arterial pressure and no fall in total body water in response to acute hypoxia indicating decreased endothelial function compared to Group 1. CONCLUSION: Rise in pulmonary artery pressure and BNP level in response to acute normobaric hypoxia indicates reduced endothelial function and can be used to screen subclinical lifestyle disease among healthy population.

Subclinical elevated B-type Natriuretic Peptide (BNP) indicates endothelial dysfunction contributing to hypoxia susceptibility in healthy individuals.

AIMS: Baseline elevated B-type Natriuretic Peptide (BNP) has been found in high altitude pulmonary edema susceptible population. Exaggerated pulmonary vascular response to hypoxia may be related to endothelial dysfunction in hypoxia susceptible. We hypothesize that baseline BNP levels can predict hypoxia susceptibility in healthy individuals. MAIN METHODS: The pulmonary vascular response to hypoxia was compared in 35 male healthy individuals divided into two groups based on BNP levels (Group 1 ≤ 15 and Group 2 > 15 pg/ml). Acute normobaric hypoxia was administered to both the groups, to confirm hypoxia susceptibility in Group 2. KEY FINDINGS: Unlike Group 1, Group 2 had elevated post hypoxia BNP levels (26 vs 33.5 pg/ml, p = 0.002) while pulmonary artery pressure was comparable. A negative correlation with tissue oxygen consumption (delta pO2) and compartmental fluid shift was seen in Group 1 only. Endothelial dysfunction in Group 2 resulted in reduced vascular compliance leading to elevation of mean blood pressure on acute hypoxia exposure. BNP showed a positive correlation with endothelial dysfunction in Group 2 and has been linked to pre-diabetic disorder (HbA1c 6 ± 0.44%) and may additionally represent a lower cross-sectional area of vascular bed related to vascular remodeling mediated by chronic hypoxia. SIGNIFICANCE: Hypoxia susceptibility in healthy individuals may be related to endothelial dysfunction that limits vascular compliance during hypoxic stress. BNP level showed positive correlation with HbA1c (r = 0.49, p = 0.04) and negative correlation with delta pO2 (r = -0.52, p = 0.04) can predict reduced microvascular compliance due to endothelial dysfunction contributing to hypoxia susceptibility in healthy individuals. BNP levels≤15 pg/ml at sea level is indicative of hypoxia resistance.