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Restoration of Retinal Vascular Responses in Type 1 Diabetic Patients

Sponsor
University of Minnesota (Other)
Overall Status
Completed
CT.gov ID
NCT02099981
Collaborator
(none)
34
Enrollment
1
Location
2
Arms
17
Actual Duration (Months)
2
Patients Per Site Per Month

Study Details

Study Description

Brief Summary

Diabetic retinopathy is the leading cause of blindness in the developed world. The causes of the disease are poorly understood. One of the earliest changes that occur in the retinas of diabetic patients, well before overt retinopathy is observed, is a reduction in light-evoked increases in blood flow in retinal vessels. The loss of this vascular response may lead to retinal hypoxia and it has been suggested that hypoxia could be a principal cause of diabetic retinopathy.

The long-term goals of this project are to determine whether decreased blood flow in diabetic patients and the resulting retinal hypoxia contributes to the development of diabetic retinopathy and whether restoration of normal blood flow in diabetic patients slows or prevents the development of retinopathy.

Condition or Disease Intervention/Treatment Phase
Phase 1

Detailed Description

The immediate goal of the proposed project is to determine whether administration of aminoguanidine (AG) restores light--evoked vasodilations in the retinas of patients without advanced retinopathy. We will also determine whether AG improves contrast sensitivity in diabetic patients. The proposed experiments are as a first step in developing new therapies to prevent diabetic retinopathy.

Study participants will be asked to come to the University of Minnesota on three (3) occasions (the visits will last for up to 2, 5 and 3 hours respectively).

Visit 1. During the screening visit (first and shortest visit), consent will be obtained and baseline labs collected (Hemoglobin A1c and Creatinine). Demographic information (date of birth, gender, race), subjects characteristics (weight, height, blood pressure and pulse) and relevant medical history will be recorded.

Visit 2. Vessel dilation testing: Control and diabetic subjects will present to the Ophthalmology Research Unit at the University of Minnesota. Prior to the imaging examination, each subject will receive dilating eye drops (1% Tropicamide) to prevent accommodation of the pupil and brief eye exam will be performed. Measurement of resting vessel diameter and light--evoked vessel dilation will be made using the Imedos Systems "Dynamic Vessel Analyzer". Subjects will be instructed to look at a fixation spot and a 350 s sequence of fundus images will be acquired during baseline and stimulation period. After completion of the initial vasodilation measurements, both control and diabetic subjects will be given 150 mg AG orally and measurement of resting vessel diameter and light--evoked vasodilation will be repeated 90 minutes later.

Visit 3. Contrast sensitivity testing: Contrast sensitivity will be assessed in un-dilated control and diabetic subjects. Contrast sensitivity will be determined both before and after AG administration using a CSV-100 test chart (VectorVision) and will be measured at 3, 6, 12, and 18 cycles per degree.

Study Design

Study Type:
Interventional
Actual Enrollment :
34 participants
Allocation:
Non-Randomized
Intervention Model:
Parallel Assignment
Masking:
None (Open Label)
Primary Purpose:
Basic Science
Official Title:
Restoration of Retinal Vascular Responses in Type 1 Diabetic Patients
Actual Study Start Date :
Jul 1, 2016
Actual Primary Completion Date :
Dec 1, 2017
Actual Study Completion Date :
Dec 1, 2017

Arms and Interventions

Arm Intervention/Treatment
Experimental: Control Group

Control subjects will receive AG.

Drug: Aminoguanidine
Other Names:
  • AG

    		•
    Experimental: Type 1 diabetes

    Type 1 diabetic subjects will receive AG.

    Drug: Aminoguanidine
    Other Names:
  • AG

    		•

    Outcome Measures

    Primary Outcome Measures

    1. The vascular response to flicker [90 minutes]

      The vascular response will be defined as the ratio of the maximal vessel diameter observed during the stimulation period, compared to the mean diameter during the control period

    Secondary Outcome Measures

    1. Contrast sensitivity [90 minutes]

    Eligibility Criteria

    Criteria

    Ages Eligible for Study:
    18 Years to 65 Years
    Sexes Eligible for Study:
    All
    Accepts Healthy Volunteers:
    Yes
    Inclusion Criteria:

    • Type 1 diabetes between 18 and 65 years of age

    • Diabetes duration between 5 to 20 years.

    • Normal report or minor findings on a dilated eye exam

    • Healthy subjects on no medications

    Exclusion Criteria:
    Current diagnosis or history of:

    • hypertension

    • dyslipidemia

    • epilepsy

    • glaucoma or other ocular disease

    • renal insufficiency/failure (creatinine >1.5 mg/dL)

    • pregnancy or breastfeeding.

    • smoker

    Contacts and Locations

    Locations

    Site City State Country Postal Code
    1 University of Minnesota Medical Center Fairview Minneapolis Minnesota United States 55455

    Sponsors and Collaborators

    • University of Minnesota

    Investigators

    • Principal Investigator: Elizabeth Seaquist, MD, University of Minnesota

    Study Documents (Full-Text)

    None provided.

    More Information

    Publications

    None provided.
    Responsible Party:
    University of Minnesota
    ClinicalTrials.gov Identifier:
    NCT02099981
    Other Study ID Numbers:
    • Protocol 22503
    First Posted:
    Mar 31, 2014
    Last Update Posted:
    Jan 18, 2018
    Last Verified:
    Jan 1, 2018
    Keywords provided by University of Minnesota
    Diabetes
    Diabetic
    Retinopathy
    Ophthalmology
    Eye
    Eyes
    Additional relevant MeSH terms:
    Retinal Diseases
    Diabetic Retinopathy
    Pimagedine

    Study Results

    No Results Posted as of Jan 18, 2018