pharmacogenomics of thiazolidinediones

Conditions: Type 2 Diabetes

Summary: the purpose of this study is to determine predictors of response to pioglitazone, an anti-diabetic medication. the investigators know from randomized clinical trials that some 30% of patients do not respond to this type of medication. there is presently no way to identify this group of patients leading to unnecessary drug exposure and medication costs.

in phase i, subjects who are eligible based on height and weight and general health information will sign informed consent. in phase ii, subjects will be screened to ensure that they fit the inclusion/exclusion criteria, including an oral glucose tolerance test. other blood tests will be performed to check complete blood count, lipids, liver functions and electrolytes. qualifying volunteers will enter phase iii, which will consist of outpatient radioimaging and body composition, metabolic testing (intravenous glucose tolerance test), and tissue biopsies. blood will also be drawn for genetic testing and for microarray studies of leukocytes. written medication information and instructions for pioglitazone, discharge instructions and satisfaction surveys following the tissue biopsy procedures will be given to subjects during the study. during phase iv, subjects will begin pioglitazone therapy. every 4 weeks throughout the drug intervention, glycemic control, lipoprotein profile, and weight will be monitored. after 12 weeks of pioglitazone therapy, the x-ray and magnetic resonance (mr) measurements of body composition, the biopsies and the metabolic tests performed during phase iii will be repeated (phase v), and blood will be drawn for microarray studies of leukocytes. thereafter, subjects will have the option to be enrolled in a 10 week, behavioral weight loss program (phase vi). following the 10-week weight loss program, a few outcome measurements will be repeated (phase vii). throughout the study, women of child bearing potential (wcbp) will have human human chorionic gonadotrophin (hcg) urine pregnancy tests. pregnancy tests will only be performed on women of childbearing potential, meaning women who are pre-menopausal and who have not had surgical sterilization. women who have not had a hysterectomy or tubal ligation at least six months prior to signing informed consent or have been postmenopausal for at least one year, will be instructed to practice one of the following methods of birth control throughout the study: oral, transdermal, or implantable hormonal contraceptives, intrauterine device, diaphragm plus spermicide, condom plus spermicide, or abstinence. pioglitazone may reduce the effectiveness of some hormonal types of contraceptives. women using hormonal methods of birth control will be advised to use a barrier method as well. female subjects are informed to notify the investigators immediately if they think they might have become pregnant during the study. participants who are eligible have 10 visits over an approximate 15-week period. participants can choose to participate in an optional weight management program for an additional 10 weeks after treatment and before their final visit.

Eligibility criteria:
inclusion criteria: * age 35-64 * bmi: ≥ 25 and ≤ 40 exclusion criteria: * pregnancy as determined by urine pregnancy test breast-feeding, or planning to become pregnant during the study * physical dimensions exceeding the limits of any equipment used * stage iii or greater congestive heart failure * symptomatic peripheral vascular disease * stroke * severe hypertension (\>170/100 mmhg) * anemia (hgb and hct \< normal reference range) * receiving treatment for thyroid, pituitary, kidney or liver disease (except controlled thyroid hormone replacement) * history of diabetes (as told by doctor, or taking diabetic medications fasting glucose value diagnostic for diabetes 2-h oral glucose tolerance test diagnostic for diabetes * rheumatoid arthritis * history of wrist, hip or leg fracture after the age of 45 * history of kidney stones * medications that the investigator judges will make interpretation of the results difficult or increase the risk of participation (e.g. anticoagulants) * any disease or condition that the investigator judges will affect bone metabolism or make interpretation of the results difficult or increase the risk of participation (e.g. anemia, cardiac decompensation, intolerance to pioglitazone, lidocaine, or other agents used)

Keywords: pioglitazone type 2 diabetes insulin sensitivity healthy adults thiazolidinediones pharmacogenetics