Niacin, N-3 Fatty Acids and Insulin Resistance
|ClinicalTrials.gov Identifier: NCT00286234|
Recruitment Status : Completed
First Posted : February 3, 2006
Last Update Posted : May 1, 2013
|Condition or disease||Intervention/treatment||Phase|
|Metabolic Syndrome Hypertriglyceridemia||Drug: omega-3 acid ethyl esters Drug: extended release niacin Drug: placebo Drug: combined treatment||Phase 4|
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The insulin resistance syndrome (IRS) afflicts approximately 25% of the US adult population. Its principal components include some or all of the following: central obesity, elevated triglyceride levels, decreased high density lipoprotein cholesterol (HDL-C) levels, a preponderance of small, dense low density lipoprotein (LDL) particles, hyperglycemia, hypertension, and increased thrombotic tendency. Subjects with the IRS are at increased risk for type 2 diabetes and/or coronary heart disease (CHD). While lifestyle changes (diet and exercise) often improve many of the manifestations of the IRS, pharmacotherapy is often needed to normalize individual components.
In recent studies from our laboratory, niacin and fish oil (n-3 fatty acids, FA) used in combination in insulin resistant individuals led to an expected improved the lipid phenotype (reduced triglycerides, increased HDL-C, and fewer, small, dense LDL particles). What was not expected, however, was that an important marker of adipose tissue insulin resistance - meal-induced suppression of free fatty acid (FFA) flux - would be improved as well. Further, knowing that these agents (given as monotherapy) have been reported to worsen glycemia in diabetic subjects, we were surprised to find no significant deterioration in glycemic control. Further preliminary studies in patients with poorly-controlled type 2 diabetes confirmed the ability of this combination of over-the-counter natural agents to significantly improve the lipid profile without adverse effects on glycemia.
Our working hypothesis is that excessive FFA flux from adipose tissue raises serum triglyceride concentrations and leads to other manifestations of the IRS. FFA flux is chronically elevated in insulin resistant subjects due to the insensitivity (i.e., resistance) of their adipocytes to the anti-lipolytic effects of insulin. Released FFA (especially from visceral adipose depots) stimulate hepatic triglyceride synthesis, leading to elevated serum triglyceride levels which subsequently contribute to reduced HDL-C and increased small, dense LDL concentrations. In addition, a high FFA flux can interfere with whole body glucose disposal. If this hypothesis is true, then interventions that improve adipocyte insulin sensitivity may be expected to improve a spectrum of risk factors associated with the insulin resistant state.
Since our preliminary studies support this hypothesis, we propose the following four specific aims which will be tested in a 4-arm, randomized, placebo-controlled, double blind trial:
Specific Aim 1. To test the hypothesis that n-3 FA and niacin (given singly and in combination) will enhance insulin-mediated suppression of FFA rate of appearance (Ra; a surrogate for adipose tissue insulin sensitivity) in insulin resistant subjects.
Specific Aim 2. To test the hypothesis that n-3 FA and niacin (given singly and in combination) will improve insulin sensitivity in insulin resistant subjects.
Specific Aim 3. To test the hypothesis that n-3 FA and niacin (given singly and in combination) will reduce VLDL-triglyceride production rates in insulin resistant subjects.
Specific Aim 4. To test the hypothesis that n-3 FA and niacin (given singly and in combination) will improve the dyslipidemic profile (i.e., reduce serum triglyceride and small, dense LDL concentrations and elevate HDL-C concentrations) in insulin resistant subjects.
At the completion of these studies, we expect to have detailed information on the potential therapeutic efficacy and the kinetic mechanism of action of combined treatment with n-3 FA and niacin. A better understanding of the action of these agents should lead to a clearer appreciation of the relationship between FFA flux and insulin resistance, to more effective therapy for the dyslipidemia of insulin resistance and ultimately to reduced risk for CAD in this burgeoning patient population.
|Study Type :||Interventional (Clinical Trial)|
|Actual Enrollment :||10 participants|
|Intervention Model:||Parallel Assignment|
|Masking:||Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)|
|Official Title:||Niacin, N-3 Fatty Acids and Insulin Resistance|
|Study Start Date :||October 2007|
|Actual Primary Completion Date :||August 2008|
|Actual Study Completion Date :||December 2008|
Placebo Comparator: 1
omacor placebo plus niaspan placebo
Drug: extended release niacin
2 g qpm
Other Name: niaspan
Drug: omega-3 acid ethyl esters
4 q qd
Other Name: lovaza omacorDrug: omega-3 acid ethyl esters
4 g qd
Other Name: lovaza omacor
Drug: combined treatment
omega-3 acid ethyl esters 4 g qd and extended release niacin, titrate up to 2 g Qpm
- Serum TG and HDL-C [ Time Frame: baseline and 4 months ]
- Insulin sensitivity, postprandial triglyceridemia, peripheral arterial tonometry [ Time Frame: baseline and 4 months ]
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00286234
|United States, South Dakota|
|Sanford Clinic Clinical Research Services|
|Sioux Falls, South Dakota, United States, 57105|
|Principal Investigator:||William S Harris, PhD||Sanford Research/USD|