Winter2016AlertDiver

the creation of proteins that build body structures and

control body functions — the individual’s observable

traits, called the phenotype.

This expression involves transcription of the code

from genes to messenger molecules that leave the

cell nuclei and enter the cell body, where they direct

synthesis of a specific protein. Gene expression is

affected by another layer of molecules (the epigenome),

which varies from cell to cell. The relationship between

genotype and phenotype is complicated further by

gene interaction with the environment. Thus, studying

genetics is complex and requires a lot of resources.

So far, genetic studies in diving have just scratched

the surface.

Changes in gene expression and transcription have

been found in animals exposed to breath-hold and

compressed-gas diving. Underwater diving exposes

divers to hyperoxia and increased production of

reactive oxygen species, which are involved with

nearly every physiological process in cells, including

programmed cell death (apoptosis). Response to this

stress alone can alter gene expression and transcription.

Similar stress may be caused by exercise in nondivers

and by many other factors.

Some studies found that experienced divers, as

compared with nondivers, showed persistent changes

in pathways of apoptosis, inflammation and immune

responses in blood transcriptomes, indicating a

cellular state of sustained alertness toward exogenous

stress. There were no measurable physiological

differences, however, between the divers and nondivers.

Changes found after scuba diving were typical of

sublethal oxidative stress; they included suppression

of lymphocyte activity and activation of the innate

immune system. It was not possible to distinguish the

effects of oxidative stress and of gas microbubbles.

Changes were similar after additional dives, and they

returned to normal in between the dives.

Whether there will be a dive analog of BRCA1 and

BRCA2 is impossible to predict at this stage. But

these are just the first steps in a long journey, and

accelerating development in medicine and technology

leaves little doubt that precision medicine for divers will

be achieved.

RESEARCH, EDUCATION & MEDICINE

EXPERT OPINIONS

WINTER 2016