Microparticles in Scuba Divers With Decompression Sickness

Decompression Sickness Clinical Trial

Official title:

Phase 1 Study Investigating Alterations of Circulating Microparticles in Scuba Divers With Decompression Sickness

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01587209
• Other study ID #: 814139
• Status: Completed
• Phase: N/A
• First received: April 23, 2012
• Last updated: August 18, 2016
• Start date: August 2011
• Est. completion date: September 2014

Study information

• Verified date: August 2016
• Source: University of Pennsylvania
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Federal Government
• Study type: Observational

Clinical Trial Summary

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).

Description:

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 1
• Est. completion date: September 2014
• Est. primary completion date: September 2014
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• Patients who are given the diagnosis of decompression sickness will be offered entry into this study

Exclusion Criteria:

• Inability to provide informed consent

Study Design

Observational Model: Case-Only, Time Perspective: Prospective

Related Conditions & MeSH terms

• Decompression Sickness
• Dysbarism

Locations

Country	Name	City	State
United States	University of Pennsylvania	Philadelphia	Pennsylvania

Sponsors (3)

Lead Sponsor	Collaborator
University of Pennsylvania	Office of Naval Research (ONR), University of Maryland

Country where clinical trial is conducted

United States, 

References & Publications (3)

Thom SR, Milovanova TN, Bogush M, Bhopale VM, Yang M, Bushmann K, Pollock NW, Ljubkovic M, Denoble P, Dujic Z. Microparticle production, neutrophil activation, and intravascular bubbles following open-water SCUBA diving. J Appl Physiol (1985). 2012 Apr;112(8):1268-78. doi: 10.1152/japplphysiol.01305.2011. Epub 2012 Feb 9. — View Citation

Thom SR, Yang M, Bhopale VM, Huang S, Milovanova TN. Microparticles initiate decompression-induced neutrophil activation and subsequent vascular injuries. J Appl Physiol (1985). 2011 Feb;110(2):340-51. doi: 10.1152/japplphysiol.00811.2010. Epub 2010 Oct 21. — View Citation

Yang M, Milovanova TN, Bogush M, Uzun G, Bhopale VM, Thom SR. Microparticle enlargement and altered surface proteins after air decompression are associated with inflammatory vascular injuries. J Appl Physiol (1985). 2012 Jan;112(1):204-11. doi: 10.1152/japplphysiol.00953.2011. Epub 2011 Sep 29. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Microparticle elevations in injured divers	We will quantify microparticles in plasma by standard flow cytometry techniques.	four years	No
Secondary	Microparticle sub-types in injured divers	We will evaluate sub-types of microparticles to determine their cells of origin.	four years	No
Secondary	Neutrophil activation in injured divers	We will evaluate presence of neutrophil activation in injured divers.	four years	No