Association between ACTN3 and acute mountain sickness

Ricardo Muller Bottura,Giscard Humberto Oliveira Lima,Debora Cristina Hipolide,João Bosco Pesquero

doi:10.1186/s41021-019-0133-8

Abstract

BackgroundDuring the process of acclimatization, when our organism needs to adjust several metabolic processes in the attempt of establishing a better oxygenation, it is normal that individuals present some symptoms that can lead to the disease of the mountain. However, not everyone presents such symptoms and individuals native of high altitudes regions present genetic differences compared to natives of low altitudes which can generate a better acute adaptation. One of these differences is the higher proportion of type I muscle fibers, which may originate from the R577X polymorphism of the ACTN3 gene. The aim of this study was to compare the response of individuals with different ACTN3 genotypes at simulated 4500 m altitude on the presence of Acute Mountain Sickness (AMS) symptoms. Twenty-three volunteers (RR = 7, RX = 8, XX = 8) spent 4 hours exposed to a simulated altitude of 4500 m inside a normobaric hypoxia chamber. Lactate and glucose concentrations, SpO2, heart rate and the symptoms of AMS were analyzed immediately before entering the chamber and at each hour of exposure. Statistical analysis was performed using IBM SPSS Statistics 21 software.ResultsOur results point to an association between AMS symptoms and the presence of R allele from R577X polymorphism.ConclusionWe conclude that individuals with at least one R allele of the R577X polymorphism seems to be more susceptible to the effects of hypoxia during the acclimatization process and may develop AMS symptoms.

Highlights

While we ascend high altitudes, the pressure of oxygen present in the air descends
Acute mountain sickness During the 4 h of exposure to low oxygen pressure mimicking high altitude, three volunteers presented scores related to Acute Mountain Sickness (AMS)
In order to verify which physiological variables could explain the presence of AMS symptoms, we performed a Generalized Estimating Eqs (GEE) in which we used the heart rate (HR), glucose, lactate and Peripherical Oxygen Saturation (SpO2) variables analyzed during the whole time of exposure to hypoxia (N = 114) and we found only SpO2 association [X2 (1, N = 114) = 3.58, p = 0.05] with the AMS (n = 2)

Summary

Introduction

While we ascend high altitudes, the pressure of oxygen present in the air descends This phenomenon is known as hypobaric hypoxia and results in decreased pressure of oxygen in arterial blood, which is called hypoxemia [1]. Not everyone presents such symptoms and individuals native of high altitudes regions present genetic differences compared to natives of low altitudes which can generate a better acute adaptation. One of these differences is the higher proportion of type I muscle fibers, which may originate from the R577X polymorphism of the ACTN3 gene. Statistical analysis was performed using IBM SPSS Statistics 21 software

Objectives

Methods

Results

Conclusion