Fatty Acid Oxidation Defects and Insulin Sensitivity

Normal Volunteers Clinical Trial

Official title:

Role of Fatty Acid Oxidation Defects in Insulin Sensitivity

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02517307
• Other study ID #: OHSU11258
• Status: Completed
• Phase: N/A
• Start date: February 2016
• Est. completion date: March 2021

Study information

• Verified date: December 2023
• Source: Oregon Health and Science University
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

The purpose of this study is to learn more about what causes insulin resistance. It has been suggested that proper breakdown of fat into energy (oxidation) in the body is important to allow insulin to keep blood sugar in the normal range. The investigators want to know if having one of the fatty acid oxidation disorders could have an influence on insulin action. Fatty acid oxidation disorders are genetic disorders that inhibit one of the enzymes that converts fat into energy. The investigators will study both normal healthy people and people with a long-chain fatty acid oxidation disorder.

Description:

The overall goal of this proposal is to investigate the effects of disordered mitochondrial fatty acid oxidation on insulin resistance in humans. Mitochondrial dysfunction has been implicated in the development of insulin resistance and type 2 diabetes during excess dietary fat intake and from increased release of endogenous free fatty acids , such as occurs in obesity. Controversy exists, however, as to whether this insulin resistance results from intrinsic defects in mitochondrial energy utilization or from abnormalities resulting from excess free fatty acid flux, as well as the role that subsequent accumulation of cellular metabolic intermediates play in impaired insulin signaling.

To address these controversies, the investigators will study a unique population of patients with inherited defects in each of the three mitochondrial enzymes in the fatty acid oxidation pathway: 1) very long-chain acyl-CoA dehydrogenase (VLCAD); 2) trifunctional protein (TFP, which includes long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD)); and 3) medium-chain acyl-CoA dehydrogenase (MCAD). These proteins are required for the oxidation of sequentially shorter fatty acids . The investigators will test the hypothesis that intrinsic defects in mitochondrial function involving oxidation of long-chain, but not medium-chain, fatty acids are sufficient to prevent intralipid-induced insulin resistance.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 41
• Est. completion date: March 2021
• Est. primary completion date: January 2021
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• confirmed diagnosis of VLCAD, LCHAD, TFP or MCAD deficiency or same gender, age and BMI as a subject with a fatty acid oxidation disorder

• ability to travel to Oregon Health & Science University, Portland, Oregon

• ability and willingness to complete the protocol

Exclusion Criteria:

• hemoglobin <10g/dl, international normalized ratio (INR) >1.2 Prothrombin time (PTT) >36 sec, Platelets <150K/mm3

• pregnant or lactating females

• endocrine disorder such as diabetes or untreated thyroid disease

• cardiovascular disease or elevated plasma lipids

• regularly taking meds that strongly affect bleeding, bruising or platelets

Related Conditions & MeSH terms

• Carnitine Palmitoyltransferase II Deficiency, Myopathic
• Insulin Resistance
• Long-chain 3-hydroxyacyl-CoA Dehydrogenase Deficiency
• Medium-chain Acyl-CoA Dehydrogenase Deficiency
• Normal Volunteers
• Protein Deficiency
• Trifunctional Protein Deficiency
• Very Long-chain Acyl-CoA Dehydrogenase Deficiency

Intervention

Drug:
• Intralipid/Heparin
Co-infusion of intralipid and heparin solutions during a hyperinsulinemic euglycemic clamp
• Glycerol/Saline
Co-infusion of a glycerol/saline solutions during a hyperinsulinemic euglycemic clamp
• Hyperinsulinemic euglycemic clamp
Infusion of insulin at at 40 mU/m2/min for 5 hours. Blood glucose will be monitored every 5 min during the insulin infusion and euglycemia will be maintained throughout the clamp by infusing 20% dextrose at a variable rate.

Locations

Country	Name	City	State
United States	Oregon Health & Science University	Portland	Oregon

Sponsors (1)

Lead Sponsor	Collaborator
Oregon Health and Science University

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Glucose Disposal Rate (Rd)- the Rate of Glucose Infusion to Maintain Euglycemia During Steady State Insulin Infusion in mg/Min	Insulin infusion induces glucose disposal into muscle and adipose tissue in insulin sensitive participants. During the glycerol co-infusion, glucose disposal will be high. Intralipid co-infusion can induce a temporary insulin resistant state. During the intralipid co-infusion, glucose disposal will be decreased. We are comparing how intralipid dampens glucose disposal between participants with a FAOD and matched control participants. Glucose disposal is measured by measuring the ratio of deuterated glucose to unlabeled glucose at the beginning and end of the clamp. The calculated glucose disposal rate or RD is mg of glucose taken into muscle and adipose tissue per minute.	Calculated during the last 30 minutes of a 300 minute clamp.
Secondary	Endogenous Glucose Production (Ra) - Calculated by the Equations of Steele During Steady State in mg/Min	Infusion of insulin will suppress endogenous glucose production from the liver in insulin sensitive people. Insulin infusion with glycerol should suppress the endogenous glucose production in the liver but intralipid induces a temporary state of insulin resistance and the decrease in endogenous glucose production or Ra will be blunted with intralipid co-infusion. We are looking at the difference in Ra with intralipid between participants with a FAOD and matched control participants. Ra or endogenous glucose production during high insulin is measured in mg new glucose synthesized per minute.	Calculated during the last 30 minutes of a 300 minute clamp.