Effect of Insulin Sensitizer Therapy on Atherothrombotic and Inflammatory Profiles Associated With Insulin Resistance

Individuals with diabetes mellitus (DM) are disproportionately affected by atherothrombotic disorders, including cardiovascular, cerebrovascular, and peripheral vascular diseases. Atherothrombotic disease risk and mortality are also increased with metabolic syndrome, a constellation of risk factors present in more than 34% of adults, even in absence of diabetes. Yet, large clinical trials of diabetes therapies have shown that conventional cardiovascular disease (CVD) risk factors, specifically hyperglycemia and hypertension, do not fully account for increased CVD risk associated with DM.

There may be an etiologic link among insulin resistance, inflammation and thrombotic events. This study seeks to determine if certain two diabetes medications (the insulin sensitizing medications) will affect certain biomarkers (or laboratory tests) for CVD in individuals with untreated DM or impaired fasting glucose.

Patients will be screened for inclusion into this this double-blinded, randomized), placebo-controlled study. If inclusion criteria are met and exclusion criteria not met, patients will be enrolled in the the study. Half of the subjects will be randomized (like the flip of a coin) to take two insulin sensitizing, anti-diabetic drugs pioglitazone (Actos) and metformin (Glucophage) taken together for three months and the other half of the subjects will take corresponding placebo (dummy) tablets.

Laboratory measurements will be obtained on the morning(s) following the two in-patient overnight stays in the Mayo Clinic Clinical Research Unit. The first stay will be at baseline and the second stay will be 3 months after baseline. Insulin sensitivity will be measured in the morning following a standardized meal the preceding night, and after an overnight fast.

The changes (from baseline to 3 months) in insulin sensitivity, glycemic control, the lipid profile, thrombotic markers and inflammatory markers will be determined and compared between the two arms of the study (placebo versus insulin sensitizing drugs).

Inclusion criteria

• We will study 30 patients with Type 2 Diabetes or impaired fasting glucose (15 men & 15 women) who are > 20 years old.
• Only patients who use lifestyle modification to manage their diabetes and are not on any oral hypoglycemic agents or insulin will be included.
• We will enroll subjects who have fasting glucose concentration greater than 100 mg/dl on two consecutive occasions and have a Body Mass Index between 27-36 kg/m^2.

Exclusion criteria

• We will exclude patients whose blood glucose is above 180 mg/dl. This will avoid the need to perform home glucose monitoring and the potential of unblinding the study by the volunteers.
• Patients taking oral hypoglycemic agents or insulin would be excluded.
• Any diseases such as active cardiovascular disease, liver diseases, kidney failure (males with serum creatinine >= 1.5mg/dl, females >=1.4 mg/dl), active endocrinopathies, debilitating chronic disease, anemia, symptoms of undiagnosed illness, history of alcoholism (alcohol use > 4oz/day) or substance abuse, chronic neurological diseases including Alzheimer's disease, stroke, etc, myopathies or any other active disease that may potentially affect the outcome measures.
• Patients on medicines such as beta blockers, corticosteroids, tricyclics, benzodiazepines, opiates, barbiturates, anticoagulants and any other drugs or preparations that may affect mitochondrial function will be excluded.
• People allergic to any of the class of drug such as lidocaine will also be excluded.
• People with pacemakers, certain aneurysm clips and claustrophobia will also be excluded as they cannot undergo magnetic resonance imaging.