Effects of Fish Oils on Inflammation and Insulin Resistance

• ClinicalTrials.gov Identifier: NCT00579436
• Recruitment Status: Completed
• First Posted: December 24, 2007
• Results First Posted: May 16, 2018
• Last Update Posted: May 16, 2018
• Sponsor: Philip Kern
• Collaborators: GlaxoSmithKline; National Institutes of Health (NIH); National Center for Research Resources (NCRR)
• Information provided by (Responsible Party): Philip Kern, University of Kentucky

Study Description

Brief Summary:

The purpose of this study is to determine whether improvement in fat and muscle metabolism after the treatment with Omacor (fish oils) provides insight into the link between obesity, fat and muscle function leading to metabolic syndrome, which is a risk factor for heart disease and diabetes.

Condition or disease	Intervention/treatment	Phase
Metabolic Syndrome; Insulin Resistance	Drug: omega-3 fatty acid; Drug: placebo	Not Applicable

Detailed Description:

The development of type 2 diabetes (T2DM) represents a complex series of events, involving abnormalities in adipose tissue lipid distribution and insulin action. Along with an increase in adipose tissue mass is an increase in inflammation brought about by macrophages that infiltrate adipose tissue. These macrophages express inflammatory cytokines such as tumor necrosis factor (TNF) and Interleukin -6 (IL-6) which are correlated with insulin resistance and metabolic syndrome, and suggest that metabolic syndrome and diabetes are conditions characterized by a state of chronic, low-grade inflammation. Thiazolidinediones (TZDs) improve insulin sensitivity via activation of peroxisome proliferator-activated receptor (PPAR) , and there is much evidence that PPAR agonists also have anti-inflammatory properties.

Fish oils are rich sources of Omega-3 fatty acids and there is a large literature on the potential benefits of fish oils on lowering serum triglycerides, cardiovascular protection, and immune modulation, and there is evidence that fish oils also activate PPAR . Hence, the focus of this study will be on subjects with insulin resistance and metabolic syndrome, but who do not yet have diabetes. We plan to treat insulin resistant subjects with fish oils and ask the following questions.

Hypothesis 1. The treatment of insulin resistant subjects with fish oils will reduce adipose tissue inflammation.

Aim 1. From blood samples drawn before and after treatment, we will measure levels of circulating inflammatory cytokines.

Aim 2. Adipose tissue biopsies will be performed before and after fish oil treatment. From the adipose biopsies, we will quantitate cytokine expression, macrophage number, and we will look for evidence of macrophage apoptosis.

Aim 3. We will determine whether fish oil treatment increases the adipose tissue secretion and serum level of the high molecular weight form of adiponectin.

Hypothesis 2. The reduction in inflammatory markers occurs through an activation of PPAR by the fish oils.

Aim 4. Adipose tissue and macrophages will be treated in vitro with fish oils in the presence and absence of a PPAR inhibitor. We will determine whether fish oils stimulate the secretion of the high molecular weight adiponectin isoform from adipose tissue and whether they induce apoptosis from macrophages, and whether this process is inhibited by the PPAR inhibitor.

Hypothesis 3. Fish oils improve peripheral insulin sensitivity through a reduction in intramyocellular lipid, and an improvement in muscle insulin signal transduction.

Aim 5. Before and after treatment with fish oils, insulin sensitivity will be measured, along with intramyocellular lipid and genes involved in insulin action and muscle lipid oxidation.

Study Design

• Study Type: Interventional (Clinical Trial)
• Actual Enrollment: 33 participants
• Allocation: Randomized
• Intervention Model: Parallel Assignment
• Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
• Primary Purpose: Basic Science
• Official Title: Effects of Fish Oils on Inflammation and Insulin Resistance
• Study Start Date: January 2007
• Actual Primary Completion Date: March 27, 2013
• Actual Study Completion Date: January 15, 2015

Arms and Interventions

Arm	Intervention/treatment
Active Comparator: Fish oil group; 4g Lovaza (omega-3 fatty acid) daily.	Drug: omega-3 fatty acid; 4g of omega-3 fatty acid daily by mouth for 12 weeks.; Other Name: Lovaza
Placebo Comparator: Control group; placebo (4 non-active capsules daily)	Drug: placebo; 4 inert capsules daily by mouth for 12 weeks.

Outcome Measures

Primary Outcome Measures :

1. Baseline Adipocyte Size [ Time Frame: baseline ]
   Prior to starting the fish oil regiment, participants will undergo an incisional abdominal biopsy to remove approximately 4g of adipose tissue to determine adipocyte size
2. Adipocyte Size After Fish Oil Treatment [ Time Frame: week 12 ]
   After completing the fish oil regiment, participant will undergo an incisional abdominal biopsy to remove approximately 4g of adipose tissue to determine individual adipocyte size

Secondary Outcome Measures :

1. Baseline Insulin Resistance [ Time Frame: baseline ]
   Insulin sensitivity (Si) was measured with a frequently sampled intravenous glucose tolerance test. Participants received a bolus of glucose at Time Zero, then a bolus of insulin 20 minutes later. Blood was collected through an IV catheter at multiple time points over the course of 4 hours. Glucose levels were plotted on a time course curve and analyzed using the MIDMOD algorithm.
2. Insulin Resistance After Fish Oil Regiment [ Time Frame: week 12 ]
   Insulin sensitivity (Si) was measured with a frequently sampled intravenous glucose tolerance test. Participants received a bolus of glucose at Time Zero, then a bolus of insulin 20 minutes later. Blood was collected through an IV catheter at multiple time points over the course of 4 hours. Glucose and Insulin levels will be plotted on a time course curve and analyzed using the MINMOD algorithm.

Eligibility Criteria

• Ages Eligible for Study: 35 Years to 65 Years (Adult, Older Adult)
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: Yes

Criteria

Inclusion Criteria:

• BMI 27-45 kg/m2
• age 35-65 years
• abnormal carbohydrate metabolism

Exclusion Criteria:

• triglycerides over 700 mg/dl
• renal disease
• liver disease
• congestive heart failure
• history of heart disease or stroke
• chronic aspirin or NSAID use (anti-coagulant)
• history of a bleeding disorder
• use of statins, fibrates, ACE inhibitors, angiotensin II receptor blockers and glucocorticoids
• diet heavy in omega-3 fatty acids (salmon, sardines, flaxseeds)

Contacts and Locations

Locations

United States, Kentucky

University of Kentucky Medical Cener

Lexington, Kentucky, United States, 40475

Sponsors and Collaborators

Philip Kern

GlaxoSmithKline

National Institutes of Health (NIH)

National Center for Research Resources (NCRR)

Investigators

• Principal Investigator: Philip A. Kern, M.D.; University of Kentucky

More Information

Publications of Results:

Spencer M, Finlin BS, Unal R, Zhu B, Morris AJ, Shipp LR, Lee J, Walton RG, Adu A, Erfani R, Campbell M, McGehee RE Jr, Peterson CA, Kern PA. Omega-3 fatty acids reduce adipose tissue macrophages in human subjects with insulin resistance. Diabetes. 2013 May;62(5):1709-17. doi: 10.2337/db12-1042. Epub 2013 Jan 17.

• Responsible Party: Philip Kern, Professor of Medicine, University of Kentucky
• ClinicalTrials.gov Identifier: NCT00579436
• Other Study ID Numbers: 74457; P20RR021954 ( U.S. NIH Grant/Contract )
• First Posted: December 24, 2007
• Results First Posted: May 16, 2018
• Last Update Posted: May 16, 2018
• Last Verified: April 2018

Keywords provided by Philip Kern, University of Kentucky:

inflammation; obesity; diabetes

Additional relevant MeSH terms:

Metabolic Syndrome; Insulin Resistance; Inflammation; Pathologic Processes; Hyperinsulinism; Glucose Metabolism Disorders; Metabolic Diseases