During the ONR-NAVSEA Progress Review Meeting that took place in Durham from July 15-17 this summer, Stephen Thom summarized the current status of his research on circulating microparticles (MPs), which are small fragments shed by various cells that have been exposed to stress. These MPs can be found in subjects with inflammation or injury and in divers after diving.
Two studies presented by Steven Thom, one with divers and the other with isolated cells, indicate a role of inert gas under pressure in nitric oxide dependent oxidative stress response which results with microparticles (MP) and inflammation. Microparticles are linked to intravascular bubbles and the cell study seems to indicate that MPs come first and bubbles after (chicken or the egg). The human study provided less obvious answers. While this represents significant progress in elucidating cellular mechanisms involved in decompression sickness, it is far from a straight forward answer. DAN contributed to this study in collaboration with University of Split, Croatia. Sixteen divers volunteered in four dives each and provided blood samples before and after their dives. DAN specialists monitored their heart rate during the dive using an underwater ecg monitor and the presence of venous gas emboli postdive using echocardiography. Additional blood samples have been collected during field studies at Innerspace, a technical diving event in Grand Cayman. Analysis of this data is pending.
The full paper “Microparticle production, neutrophil activation, and intravascular bubbles following open-water SCUBA diving” is available online.
Post written by: Petar Denoble, MD, D.Sc.
The Dive Lab 