Association between ACTN3 and acute mountain sickness

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.

Downregulation of lung miR-203a-3p expression by high-altitude hypoxia enhances VEGF/Notch signaling

“…In non-acclimatized individuals, this reduction in PaO2 can cause arterial desaturation or hypoxemia, which restricts the diffusion of oxygen into alveolar capillaries and lung tissue and may lead to lifethreatening conditions, i.e. high-altitude pulmonary edema (HAPE) and high-altitude cerebral edema (HACE) [3,5]. Normally, the alveolar capillary barrier maintains the balance of fluid exchange in the alveoli.…”

Association of Gene Variants for Mechanical and Metabolic Muscle Quality with Cardiorespiratory and Muscular Variables Related to Performance in Skiing Athletes

“…For example, the sectional area (CSA) of m. vastus lateralis and the mean CSA of slow-type fibres, which correlated with peak power output after endurance training interacted with the ACTN3 genotype [ 4 ]. Intriguingly, the rs1815739-TT genotype is also related to a better tolerance of prolonged altitude exposure which the studied elite athletes typically encounter(ed) during their adolescence and training [ 57 ].…”

“…To summarize, as classic evidence pinpointed that muscles of alpine skiers do not possess a distinct fibre type composition, but that skiers tend to have a preponderance of slow-twitch fibres, our findings of an overrepresentation of the rs1815739-TT genotype for the nonsense mutation of ACTN3 support the potential superiority of a slow fibre type distribution in high level alpine skiers. The extent to which this relates to the reportedly better coping with effects of prolonged altitude exposure for rs1815739-TT genotypes, which is typically encountered for most for the studied individuals during their adolescence and as part of their training regimes, remains to be explored [ 57 ]. We suggest that one competitive advantage that results from a slow fibre type distribution might be during intense training days, whereby simply a higher technical training volume can be performed.…”

<I>ACTN3</I> R577X Polymorphism Impacts Glucose Consumption at Simulated High Altitude

“…The study protocol was approved by the ethics committee of the Universidade Federal de São Paulo, Brazil (protocol number 2.001.055) and each subject provided informed written consent before participation. The sampling methodology has been defined previously [4].…”