Blood Gene Expression and Vascular Function Biomarkers in Professional Saturation Diving

Abstract

Saturation diving is an established way to conduct subsea operations with human intervention. While working, the divers must acclimatize to the hyperbaric environments. In this study, genome-wide gene expression and selected plasma biomarkers for vascular function were investigated. We also examined whether antioxidant vitamin supplements affected the outcome. The study included 20 male professional divers, 13 of whom took vitamin C and E supplements in doses of 1,000 and 30 mg daily during saturation periods that lasted 7–14 days. The dives were done in a heliox atmosphere with 40 kPa oxygen partial pressure (ppO2) to a depth of 100–115 m of sea-water (msw), from which the divers performed in-water work excursions to a maximum depth of 125 msw with 60 kPa ppO2. Venous blood was collected immediately before and after saturation. Following gene expression profiling, post-saturation gene activity changes were analyzed. Protein biomarkers for inflammation, endothelial function, and fibrinolysis: Il-6, CRP, ICAM-1, fibrinogen, and PAI-1, were measured in plasma. Post-saturation gene expression changes indicated acclimatization to elevated ppO2 by extensive downregulation of factors involved in oxygen transport, including heme, hemoglobin, and erythrocytes. Primary endogenous antioxidants; superoxide dismutase 1, catalase, and glutathione synthetase, were upregulated, and there was increased expression of genes involved in immune activity and inflammatory signaling pathways. The antioxidant vitamin supplements had no effect on post-saturation gene expression profiles or vascular function biomarkers, implying that the divers preserved their homeostasis through endogenous antioxidant defenses.

Change in Oxidative Stress Biomarkers During 30 Days in Saturation Dive: A Pilot Study

“…ROS are usually associated with damages and negative consequences exerted on cells but are also involved in several protective mechanisms, such as immune defense, antibacterial action, vascular tone regulation, and signal transduction [ 29 ]. Moreover, a recent research study [ 17 ] demonstrated that differential gene expression indicated reduced blood O 2 transport and increased endogenous antioxidant activity after saturation diving. During prolonged exposure to a confined, hyperbaric, hyperoxic environment, antioxidant supplementation is recommended for saturation divers to reduce oxidized molecules [ 30 ].…”

“…Antioxidant defenses are known to increase when the production of ROS is enhanced [ 7 , 15 , 16 ]. Additionally, the administration of antioxidant and vitamin supplements is an intuitive measure to boost antioxidant defenses against ROS [ 17 ]. Recent literature has demonstrated that differential gene expression indicated reduced blood O 2 transport and increased endogenous antioxidant activity after saturation diving.…”

Hyperoxia Alters Ultrastructure and Induces Apoptosis in Leukemia Cell Lines

“…In our setting, it is very complicated to set direct links between pulmonary and neurological oxygen toxicity from a clinical point-of-view. Nevertheless, we indirectly relied on actual data showing that the cellular reactions in healthy subjects undergoing a prolonged higher oxygen inspired fraction recover faster (in the first 24 h) and show no permanent damage, as shown from saturation studies (particularly on the decompression phase where the FiO2 is higher for several days) through the erythropoietin rebound reaction [58,59]. Furthermore, intermittent oxygen exposure in laboratory animals has been shown to be beneficial on tumor suppression with or without adjuvant chemotherapy [4,26,60].…”

Hemoglobin and Erythropoietin After Commercial Saturation Diving

“…Indeed, the difference in conditions between dry and wet dives ( Weathersby et al, 1990 ), including the use of hot-water suits ( Hope et al, 2005 ) and the activity level during the dive; contribute to the stress levels faced during the dives ( Møllerløkken et al, 2011 ). In a previous study of commercial saturation divers on the Norwegian Continental Shelf, the divers’ hematocrit levels were measured ( Kiboub et al, 2018 ). Data showed they were reduced post-surfacing, a possible sign of physiological acclimatization to an elevated partial pressure of oxygen (ppO 2 ) during saturation.…”