Insulin Resistance and Central Nervous System (CNS) Function in Type 2 Diabetes

Type 2 Diabetes Mellitus Clinical Trial

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00212290
• Other study ID #: DK61606 (completed)
• Status: Completed
• Phase: Phase 4
• First received: September 20, 2005
• Last updated: February 12, 2010
• Start date: November 2002
• Est. completion date: December 2006

Study information

• Verified date: February 2010
• Source: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Federal Government
• Study type: Interventional

Clinical Trial Summary

The purpose of this study is to examine the effects of treating insulin resistance on memory and attention, brain glucose utilization, and proteins in spinal fluid.

Description:

Insulin resistant conditions such as impaired glucose tolerance, type 2 diabetes mellitus, and hyperinsulinemia have been associated with an increased risk for memory decline and for Alzheimer's disease. The main study will determine whether treatment with pioglitazone or nateglinide will improve verbal memory and selective attention for older adults with impaired glucose tolerance or mild type 2 diabetes. The main study will also characterize changes in blood concentrations of insulin, inflammatory markers, and the beta-amyloid peptides that are related to Alzheimer's disease. In one sub-study, participants will undergo brain positron emission tomography (PET) imaging before and after 16 weeks of treatment with pioglitazone, nateglinide, or placebo. The purpose of this sub-study is to determine the effects of treatment on brain glucose utilization. In a second sub-study, participants will undergo a lumbar puncture procedure before and after treatment. The purpose of this sub-study is to determine the effects of treatment on spinal fluid concentrations of insulin, inflammatory markers, and beta-amyloid peptides. Together these main and sub-studies should characterize the effects of insulin resistance on cognition and suggest a mechanism by which insulin resistant conditions increase risk for memory decline and for Alzheimer's disease.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 140
• Est. completion date: December 2006
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 55 Years and older

Eligibility

Inclusion Criteria:

• Impaired glucose tolerance OR mild type 2 diabetes mellitus OR normal blood sugar regulation

• Stable weight and activity level

Exclusion Criteria:

• Medications for diabetes

• Dementia

• Medications with known effects on memory

• Serious neurologic disease or head trauma

• Serious systemic illness (e.g., renal failure or uncontrolled hypertension)

• Serious psychiatric illness (e.g., schizophrenia or bipolar disorder)

• Allergy to pioglitazone or nateglinide

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double-Blind, Primary Purpose: Treatment

Related Conditions & MeSH terms

• Diabetes Mellitus, Type 2
• Insulin Resistance
• Type 2 Diabetes Mellitus

Intervention

Drug:
• pioglitazone

• nateglinide

• placebo

Locations

Country	Name	City	State
United States	VA Puget Sound Health Care System (Seattle Campus)	Seattle	Washington
United States	VA Puget Sound Health Care System (American Lake Campus)	Tacoma	Washington

Sponsors (1)

Lead Sponsor	Collaborator
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Verbal memory (main study)
Primary	Selective attention (main study)
Primary	Plasma beta-amyloid levels (main study)
Primary	Cerebral glucose metabolism (sub-study)
Primary	Inflammatory markers in spinal fluid (sub-study)
Primary	Beta-amyloid in spinal fluid (sub-study)
Secondary	Psychomotor speed
Secondary	Verbal fluency
Secondary	Blood levels of insulin, insulin degrading enzyme, cortisol and inflammatory markers