Very Low Density Lipoprotein Turnover in Young and Elderly Individuals

May 10, 2016 updated by: The University of Texas Medical Branch, Galveston
Intrahepatic and intramyocellular lipid concentrations are elevated in elderly individuals relative to young people, despite no significant difference in fasting plasma TAG concentrations. Our general hypothesis is that the increase in intrahepatic fat with age results from reduced VLDL turnover, and therefore elderly individuals in this study will display lower VLDL turnover rates than young individuals. The aims of this study are a) to compare VLDL turnover in young and elderly individuals, and b) to compare a bolus method and a constant infusion method of assessing VLDL turnover.

Study Overview

Status

Status

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

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

Several studies have shown an association between hypertriacylglycerolaemia and coronary artery disease. Additionally, ectopic fat distribution, in particular, deposition of excess lipid within the liver and skeletal muscle, has been shown to correlate negatively with insulin sensitivity, thus presenting a metabolic milieu in which risk of developing type 2 diabetes is elevated. Previous research from our group has shown that the triacylglycerol (TAG) concentration within the liver, and within skeletal muscle fibres IMCLs (intramyocellular lipids), is increased in elderly individuals compared with young people. The elevation of lipids in these particular tissues for the elderly group was observed despite no statistically significant difference in fasting plasma TAG concentration. As the plasma TAG concentration during the postabsorptive state is largely determined by the production and clearance rates of very low density lipoprotein triacylglycerol (VLDL-TAG), and increased liver fat content has been shown to drive production of large VLDL particles, it is important to gain an understanding of whether VLDL synthesis and breakdown differs between young and elderly individuals. Such new knowledge may offer an insight into why tissue lipids are elevated in the elderly. At present, no data exist in the literature describing VLDL turnover in elderly people. We hypothesise that very low density lipoprotein turnover will be reduced in elderly individuals compared with young people. The aims of this study are a) to determine whether fractional synthesis and breakdown rates of both the protein and lipid parts of the VLDL are different between young and elderly individuals, and b) to determine whether VLDL turnover values appear different when calculated using a constant infusion tracer method as compared with a bolus tracer method. Eight young men, eight young women, eight elderly men and eight elderly women will each participate in an 8-hour infusion study. Stable isotopes of glycerol, amino acids and fatty acids will be infused, and blood samples will be drawn in intervals during the study.

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.
Observational

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.
24

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

  • United States
    • Texas
      • Galveston, Texas, United States, 77550
        • University of Texas Medical Branch, Dept of Surgery

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

60 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Sampling Method

Probability Sample

Study Population

Healthy individuals from the Galveston area.

Description

Inclusion Criteria:

  • Age 18 to 35 years, or 60 to 75 years.
  • Body mass index ≤ 27 kg•m2
  • Ability to sign informed consent.
  • Score of ≥26 for Mini-Mental State Exam

Exclusion Criteria:

  • Diabetics (plasma glucose concentration >200 mg/dl at 2 hr after oral intake of 75 g glucose).
  • Fasting plasma triacylglycerol concentration above 500 mg/dl
  • Kidney disease.
  • Liver disease.
  • Bleeding disorders.
  • Anaemia (Hb < 13 g/dl in males or < 12 g/dl in females).
  • Endocrine disease (with the exception of well-regulated hypothyroidism).
  • Positive hepatitis or HIV screens.
  • Alcohol (CAGE questionnaire; abnormal liver enzyme values) or drug abuse (amphetamines, cocaine, opioids, marijuana).
  • Lipid altering agents.
  • Score of <26 for Mini-Mental State Exam

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

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
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.
Young Males
Males, age 18-35 years. 9-hour Stable isotope infusion
Procedure: Stable Isotope Infusion
9-hour infusion of stable isotope tracers
Young Females
Females, age 18-35 years. 9-hour Stable isotope infusion
Procedure: Stable Isotope Infusion
9-hour infusion of stable isotope tracers
Older Males
Males, age 60-75. 9-hour Stable isotope infusion
Procedure: Stable Isotope Infusion
9-hour infusion of stable isotope tracers
Older Females
Females, age 60-75. 9-hour Stable isotope infusion
Procedure: Stable Isotope Infusion
9-hour infusion of stable isotope tracers

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
Very Low Density Lipoprotein (VLDL) Turnover
Time Frame: 9-hours
Turnover rates of VLDL-triglycerides and VLDL-ApoB (apolipoprotein B)-100, including synthesis and breakdown rates, measured during a 9-hour infusion trial.
9-hours

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.
The University of Texas Medical Branch, Galveston

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.
National Institute on Aging (NIA)

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: Elisabet Borsheim, Ph.D., University of Texas

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

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.
December 1, 2011

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.
July 1, 2013

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.
July 1, 2013

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 10, 2014

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.
April 10, 2014

First Posted (Estimate)

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.
April 14, 2014

Study Record Updates

Last Update Posted (Estimate)

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.
May 12, 2016

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.
May 10, 2016

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.
May 1, 2016

More Information

Terms related to this study

Keywords

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.
  • 11-318
  • 1R01AG033761-01A1 (U.S. NIH Grant/Contract)

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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