Richert, Maile L. Ceridon

Objective To identify novel genes and pathways associated with acute mountain sickness (AMS). Background The uniform, rapid transfer of adults from McMurdo Station (sea level, SL) in Antarctica to the South Pole (SP, 2835m) provides a unique opportunity to study changes in gene expression related to the body's adaptation to hypobaric hypoxia. Methods Venous blood was drawn at SL and after 2 d at SP in 98 subjects (age 37±9 y, 70% male). Peripheral blood mononuclear cells (PBMCs) were isolated and microarray analysis of the mRNA isolated from these cells was performed (Affymetrix HG U133 Plus 2 microarray chip). Analysis and the computation of expression fold changes and phenotypic regression were performed using the Bioconductor package in R. Pathway analysis was performed using MetaCore™. Results ~3200 probe sets with sig. p‐values (p<0.05) and fold changes for each subject were used in a binary logistic regression with the presence or absence of AMS during the 2 d at altitude. Corresponding p‐values and z‐values were entered into MetaCore™ for pathways analysis. Identified pathways included smooth muscle contraction, calcium signaling, and acetylcholine regulation of nerve impulses. Conclusions Probe sets associated with the presence of AMS had a significant representation in pathways involving aspects of the autonomic nervous system including smooth muscle contraction and nerve signaling. NSF B‐179‐M.

Objective To identify novel genes that change expression in healthy adults exposed to hypobaric hypoxia. Background The uniform and rapid transfer of adults from McMurdo Station (sea level, SL) in Antarctica to the South Pole (2835m, SP) provides a unique opportunity to study the changes in gene expression related to the body's adaptation to high altitude. We hypothesized that a large number of genes would change expression and that many of these genes would be associated with inflammatory processes. Methods Peripheral venous blood was drawn at SL and after 2 d at SP in 98 subjects (age 37±9 y, 70% male). Peripheral blood mononuclear cells (PBMCs) were isolated and microarray analysis of the mRNA isolated from these cells was performed (Affymetrix HG U133 Plus 2 microarray chip). Analysis and the computation of expression fold changes was performed using the Bioconductor package in R. Pathway analysis was performed using MetaCore™. Results 1118 probe sets with significant p‐values (p<0.05) and fold changes were identified and entered into MetaCore™. Several pathways including oxidative phosphorylation, cytoskeletal remodeling, and platelet aggregation were identified as having significant representation in the restricted data set. Conclusion Several pathways indicating significantly increased activity in PBMCs were identified. This is indicative of an increased inflammatory response. NSF B‐179‐M.

AbstractThis study aimed to evaluate the influence of physical activity on incidence of acute mountain sickness (AMS) by continuous activity monitoring in a free-living sample of South Pole workers over the initial 72 h at altitude exposure of 2,840 m (9,318 ft). Body Media activity monitors were worn by 47 healthy participants. AMS was defined by the Lake Louise symptom questionnaire. Venous blood samples were taken at sea level and approximately 48 h after high altitude exposure. AMS incidence was 34% (n=16/47) over the first 48 h and 40% (n=19/47) over 72 h. On day 2 at high altitude, individuals with AMS demonstrated a significantly greater increase in the percent change in physical activity metrics from baseline: total energy expenditure 19±13 vs. 5±7%, total steps 65±51 vs. 10±18%, metabolic equivalent of tasks 21±13 vs. 7±13%, and time spent performing moderate to vigorous physical activity 114±79 vs. 26±27% for individuals with AMS vs. no AMS, respectively, p<0.05. In addition, erythropoietin and vascular endothelial growth factor were 1.69 and 1.75 times higher, respectively, in those with AMS. In conclusion, workers who engaged in increased physical activity and activity intensity during initial exposure to the South Pole were more susceptible to developing AMS.