Rosiglitazone to Reverse Metabolic Defects in Diabetes

Summary

This study will examine whether the anti-diabetes medicine rosiglitazone can safely and effectively reverse the early problems of type 2 diabetes and delay the onset of disease in people with pre-diabetes. The underlying problem in people with diabetes or pre-diabetes is insulin resistance (lowered sensitivity to insulin) resulting in poor glucose (sugar) regulation. Rosiglitazone improves the body's sensitivity to insulin.

Patients 21 years of age and older who have type 2 diabetes or who are pre-diabetic (glucose intolerant/insulin resistant) may be eligible for this study. Candidates are screened with a medical history, physical examination, blood tests, echocardiography (heart ultrasound), exercise test, brachial artery reactivity test (see below), and possibly a muscle biopsy.

Participants take one rosiglitazone tablet daily by mouth for 2 weeks. The dose is then increased to two tablets daily for another 2 weeks and then to 4 tablets daily for the remainder of the 12-week treatment period. In addition to treatment, patients undergo the following tests and procedures:

* Resting and exercise metabolic testing: The amount of oxygen taken in and carbon dioxide exhaled during breathing is measured while the patient rests in a chair and then while he or she exercises on a stationary bicycle or treadmill. Both at rest and during exercise, the patient wears a facemask that measures the amount of oxygen used. During exercise, heart rate is monitored with electrodes on the chest, arms, and thighs. The exercise test is repeated three times, once to become familiar with the test, again the next day to measure exercise capacity, and again 3 days later. The third test is less strenuous and is optional.
* Muscle biopsy (optional): A small area of skin over a calf muscle is numbed with a local anesthetic and a 1-inch incision is made over the muscle. A small amount of muscle tissue is taken and the incision is closed with stitches.
* Brachial reactivity study: This ultrasound study tests how well the patient's arteries widen. The subject rests on a bed for 30 minutes. An ultrasound measuring device is placed over the artery just above the elbow. The size of the artery and blood flow through it are measured before and after inflating a pressure cuff around the forearm. The pressure cuff stops the flow of blood to the arm for a few minutes. After a 15-minute rest, a nitroglycerin tablet (medicine that causes blood vessels to relax) is placed under the patient's tongue. Before and 3 minutes after the nitroglycerin is given, the size of the artery and blood flow through it are measured again.
* Blood samples: Blood samples are collected at the beginning and end of the study and at study visits in between.
* Study visits: Patients come to the Clinical Center biweekly or monthly for a follow-up history, physical examination, and blood tests. At the end of the3-month treatment period, they receive recommendations about possible treatment modifications to best maintain glucose tolerance. Their physicians are informed of how their blood sugar was controlled. Six months after completing the study, patients undergo a final study evaluation and blood tests, and are then invited to return for yearly checkups after that.

Conditions

• Diabetes Mellitus, Type II
• Insulin Resistance

Interventions

PROCEDURE

Exercise cardiopulmonary metabolic testing

PROCEDURE

Skeletal muscle biopsy

PROCEDURE

Brachial artery reactivity testing

Sponsors & Collaborators

• National Heart, Lung, and Blood Institute (NHLBI)

  lead NIH

Study Design

Purpose

TREATMENT

Eligibility

Min Age

22 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2004-10-20

Completion

2008-09-03

Countries

• United States

Study Locations