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

Phase 2

Completed

Conditions: Type 2 Diabetes
Insulin Resistance
Metabolic Syndrome

Interventions: Drug: Placebo
Drug: metformin
Drug: pioglitazone

Registration Number: NCT00443755

Lead Sponsor: Mayo Clinic

Brief Summary: The objective of this study is to determine whether targeted pharmacological improvement of insulin sensitivity will normalize the associated elevations of thrombotic and inflammatory cardiovascular disease (CVD) biomarkers in individuals with insulin resistance.

Detailed Description: 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).

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 28

Inclusion Criteria

Not provided

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.

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Placebo	Placebo	Placebo tablets were used to match the active comparator drugs and dosing regimen.
Insulin Sensitizer Therapy	metformin	Two insulin sensitizing drugs will be taken together for 3 months; metformin 1000 mg twice daily plus pioglitazone 45 mg daily.
Insulin Sensitizer Therapy	pioglitazone	Two insulin sensitizing drugs will be taken together for 3 months; metformin 1000 mg twice daily plus pioglitazone 45 mg daily.

Primary Outcome Measures

Name	Time	Method
Change From Baseline in Insulin Sensitivity as Measured by Glucose Infusion Rate (GIR)	Baseline, 3 months	Insulin sensitivity was measured the morning after an overnight fast during an in-patient stay in the Clinical Research Unit \& was determined by the mean GIR necessary to maintain euglycemia during a hyperinsulinemic (1.5 mcIU/kg of FFM per minute)-euglycemic (85-95 mg/dL) clamp. The clamp is an 8 hour process where a hand vein is catheterized to collect blood samples and intravenous lines are used to infuse glucose, saline, insulin, phenylalanine and amino acid solutions at at pre-specified times/rates. The mean GIR was calculated as the rate per kilograms of fat-free mass (FFM) during 4 hours of steady-state (hours 4-8 of the 8 hour clamp) reported as micromols/kilogram of FFM per minute. The FFM was measured by dual-energy x-ray absorptiometry (DEXA) scan. Insulin was infused with 5% essential amino acid solution (3mL/kg of FFM/hour) to prevent the insulin-dependent decrease of amino acids during insulin infusion.

Secondary Outcome Measures

Name	Time	Method
Change From Baseline in Fasting Blood Glucose Level	Baseline, 3 months	Glucose (sugar) was measured in the blood and reported in milligrams per deciliter (mg/dL).
Change From Baseline in Glycosylated Hemoglobin (HbA1c)	Baseline, 3 months	HbA1c is a measure of average blood sugar levels over the preceding 3 month period. HbA1c was measured by ion-exchange chromatography and reported as a percentage.
Change From Baseline in Insulin Levels	Baseline, 3 months	Insulin levels in the blood were measured by immunoenzymatic assay and reported in micro International Units per milliliter (mcIU/mL).
Change From Baseline in Lipid Profile	Baseline, 3 months	Change in lipids were measured by the change from baseline to 3 months of triglycerides, high-density lipoprotein cholesterol (HDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C). All were reported in milligrams/deciliter (mg/dL).
Change From Baseline in the Thrombotic Biomarker Fibrinogen	Baseline, 3 months	Fibrinogen was measured by thrombin clotting rate assay (Beckman Coulter, Inc. Brea, California) and reported in milligrams/deciliter (mg/dL).
Change From Baseline in the Thrombotic Biomarker Plasminogen Activator Inhibitor-1 (PAI-1)	Baseline, 3 months	PAI-1 was measured by enzyme-linked immunosorbent assay (Diagnostica Stago Inc., Parsippany, New Jersey) and reported in nanograms per milliliter (ng/mL).
Change From Baseline in the Inflammatory Biomarker Interleukin 6 (IL-6)	Baseline, 3 months	IL-6 is an inflammatory cytokine and reported in picograms per deciliter (pg/dL).
Change From Baseline in the Inflammatory Biomarker C-Reactive Protein (CRP)	Baseline, 3 months	CRP is an inflammatory cytokine and is reported in milligrams per deciliter (mg/dL).
Change From Baseline in Inflammatory Biomarker Tumor Necrosis Factor-alpha (TNF-α)	Baseline, 3 month	TNF-α is an inflammatory cytokine and is reported in picograms/milliliter (pg/mL).
Change From Baseline in the Inflammatory Biomarker Adiponectin	Baseline, 3 months	Adiponectin is an anti-inflammatory cytokine and is reported in milligrams per milliliter (mg/mL).