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- Title
Coronary vasomotor abnormalities in insulin-resistant individuals.
- Authors
Qui&numl;ones, Manuel J.; Hemandez-Pampaloni, Miguel; Schelbert, Heinrich; Bulnes-Enriquez, Isabel; Jimenez, Xochitl; Hemandez, Gustavo; De La Rosa, Roxana; Yun Chon; Huiying Yang; Nicholas, Susanne B.; Modilevsky, Tamara; Yu, Katherine; Van Herle, Katja; Castellani, Lawrence W.; Elashoff, Robert; Hsueh, Willa A.; Quiñones, Manuel J; Hernandez-Pampaloni, Miguel; Hernandez, Gustavo; Chon, Yun
- Abstract
<bold>Background: </bold>Insulin resistance is a metabolic spectrum that progresses from hyperinsulinemia to the metabolic syndrome, impaired glucose tolerance, and finally type 2 diabetes mellitus. It is unclear when vascular abnormalities begin in this spectrum of metabolic effects.<bold>Objective: </bold>To evaluate the association of insulin resistance with the presence and reversibility of coronary vasomotor abnormalities in young adults at low cardiovascular risk.<bold>Design: </bold>Cross-sectional study followed by prospective, open-label treatment study.<bold>Setting: </bold>University hospital.<bold>Patients: </bold>50 insulin-resistant and 22 insulin-sensitive, age-matched Mexican-American participants without glucose intolerance or traditional risk factors for or evidence of coronary artery disease.<bold>Intervention: </bold>3 months of thiazolidinedione therapy for 25 insulin-resistant patients.<bold>Measurements: </bold>Glucose infusion rate in response to insulin infusion was used to define insulin resistance (glucose infusion rate < or = 4.00 mg/kg of body weight per minute [range, 0.90 to 3.96 mg/kg per minute]) and insulin sensitivity (glucose infusion rate > or = 7.50 mg/kg per minute [range, 7.52 to 13.92 mg/kg per minute]). Myocardial blood flow was measured by using positron emission tomography at rest, during cold pressor test (largely endothelium-dependent), and after dipyridamole administration (largely vascular smooth muscle-dependent).<bold>Results: </bold>Myocardial blood flow responses to dipyridamole were similar in the insulin-sensitive and insulin-resistant groups. However, myocardial blood flow response to cold pressor test increased by 47.6% from resting values in insulin-sensitive patients and by 14.4% in insulin-resistant patients. During thiazolidinedione therapy in a subgroup of insulin-resistant patients, insulin sensitivity improved, fasting plasma insulin levels decreased, and myocardial blood flow responses to cold pressor test normalized.<bold>Limitations: </bold>The study was not randomized, and it included only 1 ethnic group.<bold>Conclusions: </bold>Insulin-resistant patients who do not have hypercholesterolemia or hypertension and do not smoke manifest coronary vasomotor abnormalities. Insulin-sensitizing thiazolidinedione therapy normalized these abnormalities. These results suggest an association between insulin resistance and abnormal coronary vasomotor function, a relationship that requires confirmation in larger studies.
- Subjects
VASOMOTOR system; CARDIOVASCULAR system; INSULIN; DIABETES; PATIENTS; MEDICAL care
- Publication
Annals of Internal Medicine, 2004, Vol 140, Issue 9, p700
- ISSN
0003-4819
- Publication type
journal article
- DOI
10.7326/0003-4819-140-9-200405040-00009