Acute and potentially persistent effects of scuba diving on the blood transcriptome of experienced divers

Abstract

During scuba diving, the circulatory system is stressed by an elevated partial pressure of oxygen while the diver is submerged and by decompression-induced gas bubbles on ascent to the surface. This diving-induced stress may trigger decompression illness, but the majority of dives are asymptomatic. In this study we have mapped divers' blood transcriptomes with the aim of identifying genes, biological pathways, and cell types perturbed by the physiological stress in asymptomatic scuba diving. Ten experienced divers abstained from diving for >2 wk before performing a 3-day series of daily dives to 18 m depth for 47 min while breathing compressed air. Blood for microarray analysis was collected before and immediately after the first and last dives, and 10 matched nondivers provided controls for predive stationary transcriptomes. MetaCore GeneGo analysis of the predive samples identified stationary upregulation of genes associated with apoptosis, inflammation, and innate immune responses in the divers, most significantly involving genes in the TNFR1 pathway of caspase-dependent apoptosis, HSP60/HSP70 signaling via TLR4, and NF-κB-mediated transcription. Diving caused pronounced shifts in transcription patterns characteristic of specific leukocytes, with downregulation of genes expressed by CD8+ T lymphocytes and NK cells and upregulation of genes expressed by neutrophils, monocytes, and macrophages. Antioxidant genes were upregulated. Similar transient responses were observed after the first and last dive. The results indicate that sublethal oxidative stress elicits the myeloid innate immune system in scuba diving and that extensive diving may cause persistent change in pathways controlling apoptosis, inflammation, and innate immune responses.

Ascorbic acid supplementation diminishes microparticle elevations and neutrophil activation following SCUBA diving

“…There is substantial evidence that oxidative stress occurs with SCUBA diving (3,5,17,(21)(22)(23). We found that prophylactic ingestion of ascorbic acid was effective for inhibiting MP elevations and neutrophil activation due to diving.…”

“…SCUBA diving causes upregulation of antioxidant genes and elevations of plasma and intracellular antioxidant enzyme levels (3,5,17,(21)(22)(23). These changes are assumed to occur due to elevations of O 2 partial pressure associated with breathing air at depth.…”

Dynamic gene expression response to altered gravity in human T cells

“…To further assess the degree of expression alteration, we compared our results to other studies, which investigated differential gene expression in non-activated lymphocytic cells under “stress conditions” other than gravitational changes: Scuba diving influenced the blood transcriptome with differential gene expression alterations between 1.5 up to 2-fold 34 . Another study described gene expression profiles of CD4 + lymphocytes at low and very low doses of ionizing radiation showing fold changes from 1.5 up to 2-fold in most cases, and in exceptional cases of up to more than 20-fold 35 .…”

Diving into the rat plasma proteome to get to the bottom of decompression sickness

“…Recent studies suggest an inflammatory component, with activation of antioxidant genes and innate immune cells, and increased amounts of circulating extracellular vesicles (microparticles) [6,7]. However, studies of human pathophysiology are limited by obvious ethical and technical limitations to human experimentation.…”