A1 Refereed original research article in a scientific journal
Insulin induced increase in coronary flow reserve is abolished by dexamethasone in young men with uncomplicated type 1 diabetes
Authors: Laine H, Sundell J, Nuutila P, Raitakari OT, Luotolahti M, Ronnemaa T, Elomaa T, Koskinen P, Knuuti J
Publisher: BMJ PUBLISHING GROUP
Publication year: 2004
Journal: Heart
Journal name in source: HEART
Journal acronym: HEART
Volume: 90
Issue: 3
First page : 270
Last page: 276
Number of pages: 7
ISSN: 1355-6037
DOI: https://doi.org/10.1136/hrt.2003.013722
Abstract
Objective: To examine the role of the sympathetic nervous system in regulating insulin's action on coronary perfusion in uncomplicated type 1 diabetes by blocking centrally mediated sympathetic activity with dexamethasone.Methods: Positron emission tomography and oxygen 15 labelled water were used to quantify myocardial blood flow basally and during adenosine infusion with or without simultaneous euglycaemic physiological hyperinsulinaemia in nine non-smoking men with type 1 diabetes and 12 healthy non-diabetic men. Each patient was studied both with and without previous dexamethasone treatment for two days ( 2 mg/day).Results: Insulin increased coronary flow reserve in diabetic (from 4.3 (0.7) to 5.1 (0.6), p< 0.05) and non-diabetic (from 4.3 (0.3) to 5.4 (0.4), p< 0.05) patients. In contrast to non- diabetic patients dexamethasone pretreatment abolished the insulin induced increase in coronary flow reserve in diabetic patients ( p, 0.05) leading to lower coronary flow reserve in diabetic than in non- diabetic patients (3.9 (0.6) v 7.1 (0.9), p< 0.05).Conclusions: These results show that insulin's ability to modulate coronary perfusion is sustained in young patients with type 1 diabetes without microvascular complications or autonomic neuropathy. Dexamethasone treatment abolished the insulin induced increase in coronary flow reserve in diabetic patients but not in healthy study participants, suggesting that sympathetic activation plays an important part in regulating insulin's effects on myocardial perfusion in patients with type 1 diabetes.
Objective: To examine the role of the sympathetic nervous system in regulating insulin's action on coronary perfusion in uncomplicated type 1 diabetes by blocking centrally mediated sympathetic activity with dexamethasone.Methods: Positron emission tomography and oxygen 15 labelled water were used to quantify myocardial blood flow basally and during adenosine infusion with or without simultaneous euglycaemic physiological hyperinsulinaemia in nine non-smoking men with type 1 diabetes and 12 healthy non-diabetic men. Each patient was studied both with and without previous dexamethasone treatment for two days ( 2 mg/day).Results: Insulin increased coronary flow reserve in diabetic (from 4.3 (0.7) to 5.1 (0.6), p< 0.05) and non-diabetic (from 4.3 (0.3) to 5.4 (0.4), p< 0.05) patients. In contrast to non- diabetic patients dexamethasone pretreatment abolished the insulin induced increase in coronary flow reserve in diabetic patients ( p, 0.05) leading to lower coronary flow reserve in diabetic than in non- diabetic patients (3.9 (0.6) v 7.1 (0.9), p< 0.05).Conclusions: These results show that insulin's ability to modulate coronary perfusion is sustained in young patients with type 1 diabetes without microvascular complications or autonomic neuropathy. Dexamethasone treatment abolished the insulin induced increase in coronary flow reserve in diabetic patients but not in healthy study participants, suggesting that sympathetic activation plays an important part in regulating insulin's effects on myocardial perfusion in patients with type 1 diabetes.
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