Effects of Insulin Sensitizers in Subjects With Impaired Glucose Tolerance

Diabetes Clinical Trial

Official title:

Effects of Insulin Sensitizers in Subjects With Impaired Glucose Tolerance

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00108615
• Other study ID #: CLIN-013-0S3
• Status: Completed
• Phase: Phase 4
• First received: April 15, 2005
• Last updated: April 23, 2008
• Start date: January 2004
• Est. completion date: December 2007

Study information

• Verified date: April 2008
• Source: VA Office of Research and Development
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Federal Government
• Study type: Interventional

Clinical Trial Summary

Subjects with impaired glucose tolerance will be randomized to receive pioglitazone or metformin for 10 weeks. Measurements of insulin sensitivity, body composition, glucose tolerance, and muscle lipid accumulation will be performed. Adipose tissue and muscle biopsies are performed. The goal of the study is to determine whether the lipotoxiciy of impaired glucose tolerance is ameliorated by pioglitazone.

Description:

The progression to type 2 diabetes represents an evolution, which results from a vicious cycle where both glucotoxicity and lipotoxicity act to reduce insulin secretion and insulin action. Lipotoxicity is a new concept, which refers to overaccumulation of lipids in non-adipose tissue reflecting increased free fatty acid delivery. Increased fat content of skeletal muscle and islet cell is associated with insulin resistance and impaired pancreatic -cell function respectively in animal models. Whether lipotoxicity is the link between obesity and diabetes, in humans, and whether reducing intracellular fat content will improve insulin secretion and sensitivity in humans is not known. In this study, we will focus on obese subjects with impaired glucose tolerance (IGT) who have not yet developed glucose toxicity. We will examine insulin secretion, insulin action, hepatic glucose production, and muscle lipid metabolism in response to two insulin sensitizers with two different modes of action. We propose that thiazolidinediones will improve cell function by reversing lipotoxicity as reflective in reduced muscle lipid accumulation.

Hypothesis 1. In subjects with impaired glucose tolerance, who are insulin resistant and also have an insulin secretory defect, thiazolidinediones, but not biguanides, improve cell function.

Hypothesis 2. In subjects with impaired glucose tolerance, thiazolidinediones, but not biguanides, decrease the accumulation of fat in non-adipose tissues including muscle, pancreas, liver and myocardium.

Specific Aim 1. Fifty subjects with impaired glucose tolerance will be recruited and randomized to pioglitazone or metformin treatment

Specific Aim 2. cell function will be evaluated by measuring changes in acute insulin response to glucose and non-glucose secretagogues in subjects with IGT and it will be compared in response to treatment with pioglitazone versus metformin.

Specific Aim 3. The muscle fat content will be evaluated as the surrogate measure for lipotoxicity and overaccumulation of fat in non-adipose tissue. From the muscle biopsy specimens, we will measure the amount of intramyocellular triglyceride before and after treatment with pioglitazone versus metformin.

Specific Aim 4. Adipose tissue cytokine expression is associated with changes in muscle lipid accumulation.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 48
• Est. completion date: December 2007
• Est. primary completion date: April 2007
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 35 Years to 65 Years

Eligibility

Inclusion Criteria:

• Impaired glucose tolerance

• Body mass index (BMI) of 28-38

Exclusion Criteria:

• Heart disease

• Renal disease

• Liver disease

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Open Label, Primary Purpose: Basic Science

Related Conditions & MeSH terms

• Diabetes
• Glucose Intolerance
• Glucose Metabolism Disorders
• Metabolic Diseases

Intervention

Drug:
• Metformin

• Pioglitazone

• Metformin

• Pioglitazone

Radiation:
• CT scans
To measure changes in adipose tissue volumes

Procedure:
• Oral glucose tolerance test
To detect a change in glucose tolerance

Locations

Country	Name	City	State
United States	Central Arkansas Veterans HCS	Little Rock	Arkansas

Sponsors (1)

Lead Sponsor	Collaborator
VA Office of Research and Development

Country where clinical trial is conducted

United States, 

References & Publications (13)

Bodles AM, Banga A, Rasouli N, Ono F, Kern PA, Owens RJ. Pioglitazone increases secretion of high-molecular-weight adiponectin from adipocytes. Am J Physiol Endocrinol Metab. 2006 Nov;291(5):E1100-5. Epub 2006 Jun 27. — View Citation

Bodles AM, Varma V, Yao-Borengasser A, Phanavanh B, Peterson CA, McGehee RE Jr, Rasouli N, Wabitsch M, Kern PA. Pioglitazone induces apoptosis of macrophages in human adipose tissue. J Lipid Res. 2006 Sep;47(9):2080-8. Epub 2006 Jun 23. — View Citation

Di Gregorio GB, Yao-Borengasser A, Rasouli N, Varma V, Lu T, Miles LM, Ranganathan G, Peterson CA, McGehee RE, Kern PA. Expression of CD68 and macrophage chemoattractant protein-1 genes in human adipose and muscle tissues: association with cytokine expres — View Citation

Ranganathan G, Unal R, Pokrovskaya I, Yao-Borengasser A, Phanavanh B, Lecka-Czernik B, Rasouli N, Kern PA. The lipogenic enzymes DGAT1, FAS, and LPL in adipose tissue: effects of obesity, insulin resistance, and TZD treatment. J Lipid Res. 2006 Nov;47(11) — View Citation

Rasouli N, Kern PA, Reece EA, Elbein SC. Effects of pioglitazone and metformin on beta-cell function in nondiabetic subjects at high risk for type 2 diabetes. Am J Physiol Endocrinol Metab. 2007 Jan;292(1):E359-65. Epub 2006 Sep 12. — View Citation

Rasouli N, Raue U, Miles LM, Lu T, Di Gregorio GB, Elbein SC, Kern PA. Pioglitazone improves insulin sensitivity through reduction in muscle lipid and redistribution of lipid into adipose tissue. Am J Physiol Endocrinol Metab. 2005 May;288(5):E930-4. Epub — View Citation

Rasouli N, Yao-Borengasser A, Miles LM, Elbein SC, Kern PA. Increased plasma adiponectin in response to pioglitazone does not result from increased gene expression. Am J Physiol Endocrinol Metab. 2006 Jan;290(1):E42-E46. Epub 2005 Aug 23. — View Citation

Varma V, Yao-Borengasser A, Bodles AM, Rasouli N, Phanavanh B, Nolen GT, Kern EM, Nagarajan R, Spencer HJ 3rd, Lee MJ, Fried SK, McGehee RE Jr, Peterson CA, Kern PA. Thrombospondin-1 is an adipokine associated with obesity, adipose inflammation, and insul — View Citation

Varma V, Yao-Borengasser A, Rasouli N, Bodles AM, Phanavanh B, Lee MJ, Starks T, Kern LM, Spencer HJ 3rd, McGehee RE Jr, Fried SK, Kern PA. Human visfatin expression: relationship to insulin sensitivity, intramyocellular lipids, and inflammation. J Clin E — View Citation

Wolins NE, Quaynor BK, Skinner JR, Tzekov A, Croce MA, Gropler MC, Varma V, Yao-Borengasser A, Rasouli N, Kern PA, Finck BN, Bickel PE. OXPAT/PAT-1 is a PPAR-induced lipid droplet protein that promotes fatty acid utilization. Diabetes. 2006 Dec;55(12):341 — View Citation

Yao-Borengasser A, Rasouli N, Varma V, Miles LM, Phanavanh B, Starks TN, Phan J, Spencer HJ 3rd, McGehee RE Jr, Reue K, Kern PA. Lipin expression is attenuated in adipose tissue of insulin-resistant human subjects and increases with peroxisome proliferato — View Citation

Yao-Borengasser A, Varma V, Bodles AM, Rasouli N, Phanavanh B, Lee MJ, Starks T, Kern LM, Spencer HJ 3rd, Rashidi AA, McGehee RE Jr, Fried SK, Kern PA. Retinol binding protein 4 expression in humans: relationship to insulin resistance, inflammation, and r — View Citation

Yue L, Rasouli N, Ranganathan G, Kern PA, Mazzone T. Divergent effects of peroxisome proliferator-activated receptor gamma agonists and tumor necrosis factor alpha on adipocyte ApoE expression. J Biol Chem. 2004 Nov 12;279(46):47626-32. Epub 2004 Aug 31. — View Citation

* Note: There are 13 references in all — Click here to view all references

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Effects of pioglitazone and metformin on ectopic lipid accumulation		4 yr	No
Secondary	Effects of pioglitazone and metformin on beta cell responsiveness		4 yr	No