Microparticles in Scuba Divers With Decompression Sickness

August 18, 2016 updated by: University of Pennsylvania

Phase 1 Study Investigating Alterations of Circulating 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 Overview

Status

Completed

Conditions

Detailed 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.

Study Type

Observational

Enrollment (Actual)

1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19104-6068
        • University of Pennsylvania

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

SCUBA divers over age 21 that present for evaluation of suspected decompression sickness

Description

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 Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Case-Only
  • Time Perspectives: Prospective

Cohorts and Interventions

Group / Cohort
Divers with decompression sickness
The sole group under study is SCUBA divers who have sustained decompression sickness

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Microparticle elevations in injured divers
Time Frame: four years
We will quantify microparticles in plasma by standard flow cytometry techniques.
four years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Microparticle sub-types in injured divers
Time Frame: four years
We will evaluate sub-types of microparticles to determine their cells of origin.
four years
Neutrophil activation in injured divers
Time Frame: four years
We will evaluate presence of neutrophil activation in injured divers.
four years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Pennsylvania

Collaborators

University of Maryland
Office of Naval Research (ONR)

Investigators

  • Principal Investigator: Stephen R Thom, MD,PhD, University of Pennsylvania

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

August 1, 2011

Primary Completion (Actual)

September 1, 2014

Study Completion (Actual)

September 1, 2014

Study Registration Dates

First Submitted

April 23, 2012

First Submitted That Met QC Criteria

April 27, 2012

First Posted (Estimate)

April 30, 2012

Study Record Updates

Last Update Posted (Estimate)

August 22, 2016

Last Update Submitted That Met QC Criteria

August 18, 2016

Last Verified

August 1, 2016

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 814139

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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