Vitenskapelig sammendrag
Individual risk of cardiovascular injury after diving depends on the diver’s biological capacity to react to the environmental changes he or she is exposed to without loss of physiological balances. Such capacity is likely to involve intrinsic as well as acquired traits. In previous studies of arteries and heart ventricles from rats, we have observed induction of pathways of innate immunity and sensing of altered oxygen levels shortly after simulated diving (data not yet published). This resulted in elevated expression of risk markers for vascular disease (pro-thrombotic PAI1) and heart failure (natriuretic peptides ANP and BNP) both in cardiovascular tissue and blood plasma. In blood from experienced human divers we have found small but persistent increases in expression of genes involved in coagulation and platelet activation. These changes are unconnected to decompression sickness, and indicate that diving may generate long-term subclinical effects in the circulation of healthy individuals (data not yet published). Based on these observations, we hypothesise that prior cardiovascular health is involved in determining risk of injury after diving. We plan to study cardiovascular tissue- and time-dependent expression and activity of genes and proteins involved in innate immunity and altered oxygen bioavailability in rats after hyperbaric exposure, and compare these data to observable physiological responses, i.e. blood gas composition, heart- and respiratory rates and vascular gas bubble formation. Rats with low aerobic capacity and defined pro-atherosclerotic development will be used to simulate reduced cardiovascular fitness. Nutritional status may affect circulatory health, and on exposure to high oxygen levels antioxidant status in particular may be of importance. We plan to examine the effect of pre-dive administration of antioxidants on markers of cardiovascular health. Finally, we will use blood samples and physiological measurements from healthy human divers to study whether inducible rat biomarkers for risk of heart failure and vascular disease may serve as markers of diving-induced cardiovascular stress in settings of real-life diving.
Vis fullstendig beskrivelse
