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Retinal Blood Flow and Microthrombi in Type 1 Diabetes

This study has been completed.
Information provided by:
Massachusetts Eye and Ear Infirmary Identifier:
First received: November 30, 2006
Last updated: October 28, 2015
Last verified: March 2006

The project aims to find mechanisms for the abnormal retinal blood flow that in diabetic patients often precedes any evidence of clinical retinopathy and may contribute to the development of retinopathy.

Specifically, the projects tests the hypothesis that reduced retinal blood flow found in young patients with type 1 diabetes reflects increased resistance in the small vessels of the retina caused by the formation of small blood clots, called microthrombi; and that antiplatelet agents normalize the reduced retinal blood flow.

Condition Intervention Phase
Diabetic Retinopathy
Drug: aspirin
Drug: clopidogrel
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double-Blind
Primary Purpose: Diagnostic
Official Title: Retinal Blood Flow and Microthrombi in Type 1 Diabetes

Resource links provided by NLM:

Further study details as provided by Massachusetts Eye and Ear Infirmary:

Primary Outcome Measures:
  • Retinal blood flow

Secondary Outcome Measures:
  • Retinal arterial blood speed
  • Retinal arterial diameter

Estimated Enrollment: 100
Study Start Date: June 2003
Estimated Study Completion Date: March 2006
Detailed Description:

The ultimate goal of this research is to contribute to the development of strategies to prevent diabetic retinopathy. This project will test the hypothesis that antiplatelet agents normalize the reduced blood flow observed early in the course of type 1 diabetes. If the hypothesis is proven correct, the results will indicate that the formation of small blood clots (microthrombi) occurs early in diabetic retinal vessels. In turn, because microthrombosis could readily account for the occlusive microangiopathy that causes the sight-threatening stages of diabetic retinopathy, the results will propose the desirability of antiplatelet therapy for the prevention of diabetic retinopathy.

We have three specific aims:

  1. To confirm that, under basal conditions, retinal blood flow measured with the laser Doppler method in a group of type 1 diabetic patients with no or minimal retinopathy differs from the flow measured in age- and sex-matched nondiabetic control subjects;
  2. To determine whether the response of retinal blood flow to low-dose aspirin (81 mg/day) administered for 2 months versus placebo, differs between type 1 diabetic patients with no or minimal retinopathy and age- and sex-matched nondiabetic control subjects;
  3. To determine whether in type 1 diabetic patients with no or minimal retinopathy the response of retinal blood flow to low-dose aspirin differs from the response to clopidogrel, a drug that interferes with platelet function downstream of the site of aspirin action.

Ages Eligible for Study:   18 Years to 45 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Age 18-45 years,
  • type 1 diabetes duration 1-15 years,
  • absent or minimal retinopathy (EDTRS 20).
  • Age- and gender-matched healthy controls

Exclusion Criteria:

  • smoking,
  • systemic diseases other than diabetes,
  • retinal diseases other than diabetic retinopathy,
  • pregnancy,
  • bleeding disorders,
  • aspirin allergy,
  • use of anti-platelet agents,
  • non-steroidal anti-inflammatory agents,
  • angiotensin converting enzyme inhibitors,
  • angiotensin receptor antagonists,
  • Vitamin E in large doses.
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Please refer to this study by its identifier: NCT00406991

United States, Massachusetts
Schepens Eye Research Institute
Boston, Massachusetts, United States, 02114
Sponsors and Collaborators
Schepens Eye Research Institute
Principal Investigator: Mara Lorenzi, MD Schepens Eye Research Institute
  More Information Identifier: NCT00406991     History of Changes
Other Study ID Numbers: 2002-015
Study First Received: November 30, 2006
Last Updated: October 28, 2015

Keywords provided by Massachusetts Eye and Ear Infirmary:
retinal blood flow
diabetic retinopathy

Additional relevant MeSH terms:
Diabetes Mellitus
Retinal Diseases
Diabetic Retinopathy
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases
Eye Diseases
Diabetic Angiopathies
Vascular Diseases
Cardiovascular Diseases
Diabetes Complications
Platelet Aggregation Inhibitors
Purinergic P2Y Receptor Antagonists
Purinergic P2 Receptor Antagonists
Purinergic Antagonists
Purinergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs
Anti-Inflammatory Agents, Non-Steroidal
Analgesics, Non-Narcotic
Sensory System Agents
Peripheral Nervous System Agents
Anti-Inflammatory Agents
Antirheumatic Agents
Fibrinolytic Agents
Fibrin Modulating Agents processed this record on May 25, 2017