Production of Free Fatty Acids From Blood Triglycerides

November 6, 2012 updated by: Mayo Clinic

FFA Production From Triglyceride-Rich Lipoproteins

The overall hypothesis of these studies is that circulating triglycerides, coming primarily from fat in the diet, are an important source of free fatty acids. Free fatty acids are the major fat fuel in the body, and when they are elevated in the blood they are thought to raise the risk of cardiovascular disease by causing insulin resistance (in some cases leading to diabetes), raising blood pressure, and other effects. The investigator will use sophisticated methods for tracing triglycerides and free fatty acids in the blood. These methods involve the administration of low doses of radioactive and stable isotopes of naturally occurring fats. The studies will determine the contribution of triglycerides to free fatty acids in normal people and also in people with diabetes.

Study Overview

Detailed Description

Lipid energy is transported in the blood in several forms, including chylomicrons and free fatty acids (FFA). Chylomicrons are key elements in the absorption and storage of dietary fat, and also play a role in the pathogenesis of atherosclerosis via the production of remnant particles, but their role as a direct fuel source has not been explored. FFA are the major lipid fuel in the body, and increases in their concentration have been shown to cause insulin resistance, endothelial dysfunction and increases in the production of very low density lipoproteins. FFA are released into the blood through the action of hormone sensitive lipase on triglyceride stores in fat cells. Very little is known about the role of chylomicrons in FFA metabolism, but the potential contribution of chylomicrons to FFA is considerable, especially in people who consume high fat diets. Initial studies indicate that in addition to the role of chylomicrons in fat storage, a portion of chylomicron fatty acids are released as FFA in a process called "spillover". These studies indicate that the contribution of chylomicrons to FFA is increased in type 2 diabetes. A study of spillover in the splanchnic bed found very high rates of splanchnic spillover in overweight and obese individuals with hypertriglyceridemia. Extremely accurate and precise methods have been developed by the investigator for the measurement of the concentration and specific activity of FFA and chylomicron triglyceride fatty acids in plasma. In addition, a tracer method for accurately determining the kinetics of chylomicrons has been developed. In the proposed studies, the tracer technique will be used to systematically investigate the contribution of chylomicrons to total FFA availability. The technique will be applied to normal subjects at rest and after exercise, as well as subjects with type 2 diabetes mellitus and hypertriglyceridemia. Specifically, these studies will: 1) determine whether weight loss in people with type 2 diabetes reduces spillover from chylomicrons; 2) determine whether acute lowering of FFA with insulin infusion reduces spillover in nondiabetic individuals with dyslipidemia; 3) determine whether noninsulin-mediated lowering of FFA reduces spillover in diabetic individuals with dyslipidemia, and 4) determine whether obese, insulin-resistant individuals have increased spillover in the splanchnic bed.

Study Type

Observational

Enrollment (Actual)

16

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Minnesota
      • Rochester, Minnesota, United States, 55905
        • Mayo Clinic

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

35 years to 60 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Probability Sample

Study Population

Volunteers from the region around Rochester, Minnesota who meet the inclusion criteria will be recruited.

Description

Inclusion Criteria:

  • Type 2 diabetes
  • Atherogenic dyslipidemia
  • Obesity

Exclusion Criteria:

  • Kidney disease
  • Liver disease
  • Coronary artery disease
  • Retinopathy
  • Neuropathy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Time Perspectives: Cross-Sectional

Cohorts and Interventions

Group / Cohort
Diabetes/weight loss
12 individuals with type 2 diabetes and hypertriglyceridemia
Nondiabetic/hypertriglyceridemic
10 insulin resistant nondiabetic individuals with dyslipidemia
Normotensive/nondiabetic
10 insulin resistant, normotensive, nondiabetic individuals
Insulin resistant/dyslipidemic
14 insulin resistant nondiabetic individuals with dyslipidemia

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Spillover of free fatty acids from chylomicrons
Time Frame: Measured at 1 to 6 days
Measured at 1 to 6 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Investigators

  • Principal Investigator: John M. Miles, MD, Mayo Clinic

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

June 1, 2008

Primary Completion (Actual)

January 1, 2012

Study Completion (Actual)

January 1, 2012

Study Registration Dates

First Submitted

May 29, 2009

First Submitted That Met QC Criteria

June 1, 2009

First Posted (Estimate)

June 2, 2009

Study Record Updates

Last Update Posted (Estimate)

November 7, 2012

Last Update Submitted That Met QC Criteria

November 6, 2012

Last Verified

November 1, 2012

More Information

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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