Duality of Lipids: the Athlete's Paradox (LIDDIA)

June 10, 2023 updated by: German Diabetes Center

The Dual Role of Intramyocellular Lipids in Mediating Insulin Resistance: Assessing the Mechanisms of the Athlete's Paradox

Accumulation of intramyocellular lipids (IMCLs) due to increased supply of fatty acids can induce defects in the insulin signaling cascade, causing skeletal muscle insulin resistance. However, the causes for muscle insulin resistance are not well understood. The association of elevated IMCLs and insulin resistance has been shown in obese humans and individuals with type 2 diabetes as well as several animal models of insulin resistance. Despite the strong relationship between IMCLs and insulin resistance, this suggested relationship disappears when well-trained endurance athletes are included into this consideration as this group is highly insulin sensitive. This metabolic enigma has been termed the 'athlete's paradox'. The aim of this project is to resolve the mechanisms contributing to the athlete's paradox.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Type 2 diabetes (T2D) is characterized by an increasing insensitivity of muscle, fat and liver cells to the hormone insulin. About 9% of the global population is affected by this condition and mortality risk is twice as high in individuals with diabetes compared to similar-aged people without diabetes.

Muscle is of particular importance for glucose homeostasis, since in healthy subjects it accounts for 80-90% of postprandial insulin-stimulated glucose disposal. After cellular uptake of glucose by the specialized glucose transporter 4 (GLUT4), glucose is phosphorylated and stored as glycogen. In individuals with obesity or T2D, the capacity for insulin to facilitate glucose uptake and glycogen synthesis is impaired. This reduced response of a given insulin concentration to exert its biological effect is termed insulin resistance. Subsequent diminished insulin secretion due to β-cell failure results in fasting hyperglycemia and overt diabetes. Importantly, muscle insulin resistance is the initial defect occurring in the development of T2D and precedes the clinical development of the disease by up to 20 years. Intracellular defects in glucose transport have been identified as the limiting step for insulin-mediated glucose uptake into skeletal muscle. Impaired muscle glucose transport activity is likely a consequence of ectopic lipid accumulation and subsequent dysregulation of intramyocellular fatty acid metabolism. Indeed, results from normal weight, nondiabetic adults suggest that intramyocellular triglyceride content is a strong predictor for muscle insulin resistance. Of note, the development of insulin resistance occurred without changes in intramyocellular triglyceride content, thus dissociating the amount of these neutral storage lipids from insulin resistance. Instead, the bioactive lipid species diacylglycerols (DAG) and ceramides have been implicated in interfering with insulin signaling and glucose homeostasis in obese and insulin resistant individuals and individuals with T2D by activating members of the protein kinase C (PKC) family while ceramides mediate an increase in protein phosphatase 2A (PP2A) and an association of PKCζ and protein kinase B (PKB)/Akt2. To add another layer of complexity, DAGs seem to exert their detrimental intracellular effects in a subspecies- (mostly C18:0, C18:1, or C18:2 DAGs) and stereo-selective manner (sn-1,2 stereoisomer DAG). Taken together, excessive amounts of bioactive intramyocellular lipids (IMCLs) contribute to defective insulin signaling in obese individuals and patients with T2D. Surprisingly, endurance athletes have comparable amounts of IMCLs, but remain highly insulin sensitive. This metabolic conundrum has been termed "athlete's paradox".

This study therefore aims at resolving this conundrum with mass-spectrometry based state-of-the-art methodology by analysing lipid subspecies in endurance-trained athletes, untrained healthy individuals and insulin-resistant individuals.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
100

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

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

  • Germany
    • NRW
      • Düsseldorf, NRW, Germany, 40225
        • German Diabetes Center
  • Netherlands
      • Maastricht, Netherlands, 6200
        • Maastricht University

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

14 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion criteria

  • Insulin-resistant, non-athletic persons with a comparable content of IMCLs as the athletes
  • Healthy, insulin-sensitive, normal-weight, non-athletic (BMI 18-25 kg / m2) individuals
  • Endurance trained individuals (VO2max≥60 mL / kg / min ♂ and 45 mL / kg / min ♀)
  • Male and female, age between ≥ 18 and ≤ 69 years

Exclusion criteria

  • Acute infections / fever
  • Immunosuppressive therapy
  • Serious heart, kidney or liver disease: - New York Heart Association-Classification (NYHA) stage ≥ II - creatinine ≥ 1.6 mg / dl - Aspartate Aminotransferase (AST) or Alanine Aminotransferase (ALT) ≥ two-fold upper reference value - severe peripheral artery disease (PAD) (stage IV)
  • autoimmune diseases
  • Anemia (Hb <12g / l)
  • Severe psychiatric illness or addiction
  • Malignant cancer
  • Participation in another intervention study
  • Blood clotting disorders or increased risk of thrombosis
  • Pregnancy, lactation
  • Cigarettes (or non-smokers <1 year)
  • alcohol consumption (men> 30g / d, women> 20g / d)
  • ECG changes (ST reductions or - elevations, high-grade rhythm disorders (salvage or polytope extrasystoles, ventricular tachycardia)
  • Heart diseases (angina pectoris at rest or under light load, myocardial infarction, thromboembolic processes / pulmonary embolism or severe arteriosclerosis, acute myocarditis or pericarditis, cardiac wall aneurysms, cor pulmonale, aortic stenosis)
  • Hypertension (> 220/120 mmHg)
  • Pacemaker
  • Metallic and magnetic implants (for example, mechanical heart valves, joint prostheses, clip after vascular surgery, middle and inner ear implants or fresh dental implants, penis implants)
  • Waist circumference> 135cm
  • Claustrophobia

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

  • Primary Purpose: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Acute bout of endurance exercise
Intramyocellular lipid metabolism will be assessed in insulin resistant and healthy, sedentary individuals after an acute bout of endurance exercise.
Procedure: Acute bout of endurance exercise
Individuals will undergo an acute bout of endurance exercise for 90 min at 75% of maximal oxygen uptake.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Assessment of intramyocellular lipid content via magnetic resonance spectroscopy
Time Frame: 2 years
Intramyocellular lipid content assessed via magnetic resonance spectroscopy (%lipid) in endurance-trained athletes and sedentary individuals
2 years
Assessment of intramyocellular lipid composition via mass spectrometry
Time Frame: 2 years
Detailed composition of intramyocellular lipids assessed via mass spectrometry (concentration of bioactive lipids) in endurance-trained athletes and sedentary individuals
2 years

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
German Diabetes Center

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Maastricht University

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Michael Roden, Prof., MD, German Diabetes Center

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
April 3, 2017

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 1, 2023

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 1, 2023

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 3, 2017

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 18, 2017

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 19, 2017

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 13, 2023

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 10, 2023

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2023

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • DDZ-LIDDIA01

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

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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