Skin and Retina Microvascular Endothelial Function in Healthy, Insulin Resistant and Type 2 Diabetic Subjects

NCT ID: NCT01241370

Last Updated: 2010-11-16

Basic Information

• Recruitment Status: COMPLETED
• Total Enrollment: 78 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2009-05-31
• Study Completion Date: 2010-04-30

Brief Summary

The purpose of this study is to investigate microvascular endothelial function in the retina of lean, obese, and type 2 diabetic subjects and to compare microvascular endothelial function in the retina with several other established markers of endothelial and microvascular function.

Detailed Description

Insulin resistance is an early feature in obese patients lasting from hyperinsulinaemia with normal glycaemic control to impaired glucose tolerance and clinically manifest type 2 diabetes. Insulin resistance is closely associated to endothelial dysfunction and many other cardiovascular risk markers summarised under the definition of the metabolic syndrome. During the recent years, insulin resistance and the development of endothelial dysfunction were recognized as important pathogenetic drivers in the development of atherosclerosis and major predictors in the development of micro and macrovascular complications like retinopathy, nephropathy, myocardial infarction or stroke.

Several different technologies have been developed for the measurement of endothelial function in distinct vascular compartments like the flow mediated vasodilatation in the brachial artery, or numerous laser Doppler based technologies for the measurement of endothelial dependent microvascular blood flow responses in the skin. Even retinal vascular morphology could be easily visualized by direct fundoscopy, the investigation of retinal endothelial function had been a diagnostical challenge for decades. During the recent years, laser doppler scanning of the retina has become a widely used technology for the measurement of microvascular blood flow in the retina. Recently a new stimulation technology for the investigation of endothelial function in the retina has been developed and validated. Application of flickering light to the retina increases retinal blood flow by the stimulation of endothelial nitric oxide (NO) release, and laser Doppler scanning of the retina before and after the flicker light application could be used for the investigation of microvascular endothelial function in the eye. For assessing the stage of retinopathy a retinal image of 45° (papilla-centered) will be performed using a digital non-mydriatic fundus camera (Kowa Nonmyd 5). The image will be evaluated in respect to diabetic and hypertensive retinopathy in a standardized method. Also the equivalent arteriolar and venous diameter of the retinal vessels will be measured and the arterio-venous ratio will be calculated.

Conditions

Diabetes Mellitus, Type 2

Keywords

Retinal endothelia dysfunction; Type 2 diabetes mellitus; Insulin-resistance; micro-lightguide spectrophotometry; laserdopplerfluxmetry

Study Design

• Observational Model Type: CASE_CONTROL
• Study Time Perspective: PROSPECTIVE

Study Groups

Lean healthy subjects

Homeostasis Model Assessment score (HOMAs) ≤ 2, Body Mass Index (BMI) ≤ 28 kg/m2

No interventions assigned to this group

Insulin-resistnat subjects

HOMAs \> 2, BMI \> 28 kg/m2

No interventions assigned to this group

Type 2 diabetic patients

No interventions assigned to this group

Eligibility Criteria

Inclusion Criteria

• Age: 30 to 70 years
• Have given informed consent to participate in this study in accordance with local regulations
• Are reliable and willing to make themselves available for the duration of the study and will abide by the study restrictions

Exclusion Criteria

• Smoking within the last 6 months
• Pre-proliferative or proliferative diabetic retinopathy
• Have a history of drug or alcohol abuse within the last 5 years
• Pregnant or intend to become pregnant during the course of the study
• Have a condition (including known drug abuse, alcohol abuse, or psychiatric disorder) which, in the opinion of the investigator, precludes the patient from following and completing the protocol
• Epilepsy
• Lack of compliance or another, similar reason, that, in the judge of the investigator, precludes satisfactory participation in the study.
• Treatment with nitrates, angiotensin converting enzyme (ACE)-inhibitors, or angiotensin (AT) II blockers
• Treatment with glitazones

• Minimum Eligible Age: 30 Years
• Maximum Eligible Age: 70 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Institute for Clinical Research and Development (ikfe) GmbH

UNKNOWN

Sponsor Role: collaborator

Johannes Gutenberg University Mainz

OTHER

Sponsor Role: collaborator

University of Erlangen-Nürnberg Medical School

OTHER

Sponsor Role: collaborator

ELAB-Logistics

INDUSTRY

Sponsor Role: lead

Responsible Party

ikfe GmbH

Principal Investigators

Thomas Forst, MD

Role: PRINCIPAL_INVESTIGATOR

Ikfe GmbH

Locations

ikfe GmbH, clinic

Mainz, , Germany

Countries

Germany

Other Identifiers

IKFE-RET-001

Identifier Type: -

Identifier Source: org_study_id