Quantification of Rising the Osmotic Pressure in Diabetic Intraretinal Fluid Accumulation (Diabetic Macular Oedema)

September 18, 2012 updated by: Birgit Sander, Glostrup University Hospital, Copenhagen

Diabetic Macular Oedema: the Retinal Thickness as a Function of Changes in Plasma Osmolality Evaluated by OCT.

Diabetic macular oedema is characterized by fluid accumulation in the retinal tissue from leaking retinal vessels, the capillaries. This state can lead to severe visual loss and blindness. According to basic physiologic rules several factors influence the fluid transport between the capillaries and the surrounding tissue. One of these factors is the balance between the large molecules within the vessel lumen and the retinal tissue. Some drugs change this balance, the osmotic balance, by moving the fluid from the tissue to the vessel lumen. In relation to diabetic macular oedema, treatment with such a drug potentially would reduce the retinal thickness because it extracts fluid from the retinal tissue. Glycerol has this potential. If reduction of the thickness with glycerol is confirmed, then it proves the significance of the osmotic balance in the basic nature of diabetic macular oedema.

In this study we therefore examine the time dependent change in retinal thickness after glycerol intake by an instrument called optical coherence tomography (OCT). The participants drink glycerol and the thickness of the retina is then monitored closely by OCT during the following three hours. Since diabetic changes in the retina are focal pr. definition, the secondary purpose of the study is to find any regional differences in the response. The examinations are repeated at a second visit where the patient drink another dose of glycerol, because we also want to analyse for a dose dependent response. Which dose is given at each visit is randomised on beforehand. In addition to measuring the retinal thickness a variety of examinations are performed both before and during the study, e.g. blood samples and systemic blood pressure measurements.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

In general, when oedema is present, increasing the osmotic pressure in the retinal capillaries by an osmotic drug induces transcapillary fluid transport from the retinal tissue to the vascular lumen, according to the Starling equation. Theoretically, in diabetic macular oedema the event would lead to reduction of the retinal thickness, which could then be visualised by Optical Coherence Tomography. The main purpose of this trial is therefore to evaluate and quantify the changes in retinal thickness of the oedema after increasing the intracapillary osmotic pressure with glycerol ingestion. A reduction of the retinal thickness will confirm the application of the Starling osmotic forces on diabetic macular oedema. Secondly, we want to describe any regional differences in the retinal response and analyse for dose dependent variations.

Principles of material and methods: A prospective, randomized, clinical trial on 15 patients with diabetic significant macular oedema. At baseline the patients undergo a thorough ophthalmologic examination including ETDRS visual acuity, slit lamp biomicroscopy, Optical Coherence Tomography (Stratus-OCT), 7-field fundus photography followed by fluorescein angiography. In addition the systemic blood pressure is measured and blood samples are taken to rule out severe renal insufficiency and to estimate glycosylated haemoglobin.

The patients are all randomised to drink either 1.5 or 3 mL glycerol/kg body weight (max. 250 mL pr day) on the first of two visit dates. The last dose is given at the second visit. In the following three hours the retinal thickness is then monitored closely by Stratus-OCT after the glycerol ingestion.

The plasma osmolality and plasma triglyceride (an indirect indicator of glycerol) are confirmed by venous blood samples, also at predetermined times after the last swallow of glycerol. In addition the systemic blood pressure and the capillary blood glucose are monitored closely during the visit.

Study Type

Interventional

Enrollment (Actual)

15

Phase

  • Not Applicable

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

  • Denmark
      • Herlev, Denmark, DK-2730
        • Department of Ophthalmology, Herlev Hospital, University of Copenhagen, Herlev Ringvej 75

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

Description

Inclusion Criteria:

  • Diabetic significant macular oedema (by biomicroscopy or OCT)
  • Visual acuity of minimum 60 letters by the ETDRS chart (4 m distance)
  • ETDRS grade between 35 and 53, both stages included
  • baseline blood pressure of max. 160/90 mmHg
  • informed consent

Exclusion Criteria:

  • another macular disease than diabetic macular oedema to explain the symptoms, incl. prior laser photocoagulation
  • pregnancy
  • moderate to severe heart or lung disease (crural oedemas, dyspnoea during low activity, or basal crackles by lung stethoscopy
  • renal insufficiency with albumin excretion larger than 300 g/day

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

  • Primary Purpose: Basic Science
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Retinal thickness by fast retinal thickness mapping by optical coherence tomography at times 0, 2, 4, 8, 10, 15, 20, 30, 60, 90, 120 and 180 minutes after the last swallow of glycerol.

Secondary Outcome Measures

Outcome Measure
Regional differences in response by fast retinal thickness mapping by optical coherence tomography at times 0, 2, 4, 8, 10, 15, 20, 30, 60, 90, 120 and 180 minutes after the last swallow of glycerol
dose dependent differences in the same time spectrum.

Collaborators and Investigators

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

Sponsor

Glostrup University Hospital, Copenhagen

Investigators

  • Principal Investigator: Dorte Nellemann Thornit, MD, Department of Ophthalmology, Glostrup Hospital, University of Copenhagen, Nordre Ringvej 57, DK-2600 Glostrup, Denmark

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

December 1, 2004

Primary Completion (Actual)

February 1, 2006

Study Completion (Actual)

April 1, 2007

Study Registration Dates

First Submitted

June 2, 2006

First Submitted That Met QC Criteria

June 2, 2006

First Posted (Estimate)

June 6, 2006

Study Record Updates

Last Update Posted (Estimate)

September 19, 2012

Last Update Submitted That Met QC Criteria

September 18, 2012

Last Verified

September 1, 2012

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Dorte Nellemann, glycerol

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

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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