The Autonomic Nervous System and the Metabolic Syndrome
The overall goal of this proposal is to determine the role of the autonomic nervous system in the insulin resistant state associated with obesity and the metabolic syndrome. Obesity results from an accumulation of excessive fat deposit due to increase caloric intake or decrease energy expenditure, this condition is usually associated with diseases such as hypertension or diabetes, a cluster known as the metabolic syndrome. The first step in the development of the metabolic syndrome is a resistance to the action of insulin. The mechanism underlying insulin resistance in obesity is still unknown, however some investigators have proposed that the autonomic nervous system, particularly the increase sympathetic activation in obesity may play an important role. We have extensive experience studying the role of the autonomic nervous system in the cardiovascular alterations associated with obesity by producing complete autonomic withdrawal with a drug named trimethaphan. We propose to use the same approach to study the role of the autonomic nervous system in the development of insulin resistance in obesity.
|Study Design:||Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single Blind (Subject)
|Official Title:||The Autonomic Nervous System and the Metabolic Syndrome|
- Insulin resistance [ Time Frame: Duration of the intervention ] [ Designated as safety issue: No ]
- Muscle sympathetic nerve activity [ Time Frame: Duration of the intervention ] [ Designated as safety issue: No ]
|Study Start Date:||August 2008|
|Estimated Study Completion Date:||December 2014|
|Estimated Primary Completion Date:||December 2014 (Final data collection date for primary outcome measure)|
Active treatment arm. Transient autonomic blockade with Trimethaphan and blood pressure restoration with L-NMMA will be used during insulin clamp
Drug: Trimethaphan L-NMMA Insulin clamp
Trimethaphan 4 mg/min IV will be infused for the duration of the study. L-NMMA 125-500 mcg/k/min IV will be titrated to restore blood pressure to pre-trimethaphan levels Insulin clamp will be used to determine insulin resistance
Placebo Comparator: 2
Saline will be used instead of trimethaphan during insulin clamp
Drug: Saline, Insulin clamp
Saline IV infusion to simulate trimethaphan infusion in active arm Insulin clamp will be done to determine insulin resistance
The purpose of this study is to look at the role of the autonomic nervous system, an involuntary nervous system that controls your blood pressure, in insulin resistance and the metabolic syndrome. Insulin is a substance that helps your body use the sugar in the food that you eat. Some people's tissues stop reacting in a normal way to insulin, a condition known as insulin resistance. A person with insulin resistance can have other health problems, such as obesity, high cholesterol, and high blood pressure. These problems together are called the metabolic syndrome. We think that the autonomic or involuntary nervous system controls the way your body responds to insulin. This system is changed in obese people, and we think that it may cause the insulin resistance. We plan to study this with two drugs -trimethaphan and L-NMMA. Neither of these drugs are approved by the Food and Drug Administration (FDA), and they will be used for research purposes only.
Fifty people will take part in this study.
|United States, Tennessee|
|Vanderbilt University Medical Center|
|Nashville, Tennessee, United States, 37232|
|Principal Investigator:||Italo Biaggioni, M.D.||Vanderbilt University|