Microparticles in Scuba Divers With Decompression Sickness
The investigators hypothesize that membrane microparticles (MPs) are liberated into the blood stream in response to decompression stress and that certain MPs characteristics initiate inflammatory responses that contribute to the clinical syndrome the investigators call decompression sickness. The research goal is to evaluate the number, type and time-course for elevations in MPs in sport SCUBA divers who present for treatment of decompression sickness. Blood samples are to be taken from consenting patients before and after they undergo treatment for decompression sickness and at a follow-up clinic visit from 1 to 3 weeks later (three samples total).
|Study Design:||Observational Model: Case-Only
Time Perspective: Prospective
|Official Title:||Phase 1 Study Investigating Alterations of Circulating Microparticles in Scuba Divers With Decompression Sickness|
- Microparticle elevations in injured divers [ Time Frame: four years ] [ Designated as safety issue: No ]We will quantify microparticles in plasma by standard flow cytometry techniques.
- Microparticle sub-types in injured divers [ Time Frame: four years ] [ Designated as safety issue: No ]We will evaluate sub-types of microparticles to determine their cells of origin.
- Neutrophil activation in injured divers [ Time Frame: four years ] [ Designated as safety issue: No ]We will evaluate presence of neutrophil activation in injured divers.
|Study Start Date:||August 2011|
|Estimated Study Completion Date:||April 2015|
|Estimated Primary Completion Date:||April 2015 (Final data collection date for primary outcome measure)|
Divers with decompression sickness
The sole group under study is SCUBA divers who have sustained decompression sickness
Microparticles (MPs) are small membrane bound vesicles shed from the surface of a variety of cells by what appear to be well regulated processes. They are elevated in many physiological and disease states and in some instances have been associated with organ injury. Shear stress - as can be caused by intravascular bubbles - is one of the stimuli known to cause cells to release microparticles. Most sport SCUBA dives have been shown to generate intravascular bubbles - even safe dives well within limits established by the US Navy and sports authorities. The investigators have reported elevations in several sub-types of MPs in a group of individuals undergoing a well monitored series of open-water SCUBA dives. There is no information of the occurrence of MPs in injured divers. The investigators have published results using a murine model which demonstrated that mice subjected to varying decompression stresses exhibit progressive elevations in circulating MPs derived from leukocytes, erythrocytes, platelets and endothelial cells. Using novel interventions the investigators demonstrated that MPs cause intravascular neutrophil activation and inflammatory perivascular injuries. Therefore, there is pathophysiological information to suggest that one or more element of MPs (number and/or pro-inflammatory subtype) may be proximal elements that precipitate the clinical syndrome the investigators call decompression sickness.
|Contact: Stephen R Thom, MD, PhDfirstname.lastname@example.org|
|Contact: Kevin R Hardy, MD||215-898-9095||Kevin.Hardy@uphs.upenn.edu|
|United States, Pennsylvania|
|University of Pennsylvania||Recruiting|
|Philadelphia, Pennsylvania, United States, 19104-6068|
|Contact: Stephen R Thom, MD,PhD 215-898-9102 email@example.com|
|Contact: Kevin R Hardy, MD 215-898-9095 "Hardy, Kevin" <Kevin.Hardy@uphs.upenn.edu>|
|Principal Investigator: Stephen R Thom, MD,PhD|
|Principal Investigator:||Stephen R Thom, MD,PhD||University of Pennsylvania|