Restoration of Retinal Vascular Responses in Type 1 Diabetic Patients
| Status: | Completed |
|---|---|
| Conditions: | Ocular, Diabetes |
| Therapuetic Areas: | Endocrinology, Ophthalmology |
| Healthy: | No |
| Age Range: | 18 - 65 |
| Updated: | 1/20/2018 |
| Start Date: | July 2016 |
| End Date: | December 2017 |
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.
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.
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.
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.
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
We found this trial at
1
site
2450 Riverside Ave
Minneapolis, Minnesota 55454
Minneapolis, Minnesota 55454
(612) 273-3000
Principal Investigator: Elizabeth Seaquist, MD
University of Minnesota Medical Center, Fairview Improving patients' lives drives the innovation that makes University...
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