Muscle Protein Synthesis Rates After Protein Consumption in Lean, Overweight, and Obese Adults

October 24, 2016 updated by: Nicholas Burd, University of Illinois at Urbana-Champaign
There are an increasing number of individuals in the United States with obesity, and this is a major health concern with links to many chronic diseases. Impairments in protein metabolism with obesity may disrupt muscle function and modify the dietary protein requirements in obese individuals. Further, overweight and obese type 2 diabetics exhibit dramatically reduced skeletal muscle mass compared with lean, healthy controls. Surprisingly, the influence of being overweight or obese on this decline in muscle mass remains understudied, despite clear evidence that similar metabolic impairments typically exist in these populations prior to the development of overt diabetes. Protein ingestion provides the amino acid building blocks to synthesize and repair muscle proteins in adults. Previous research has shown that the muscle protein synthetic response to food ingestion may be reduced in overweight/obese adults. However, this research provided the 'free' amino acids in small portions every 15 min during the postprandial period. In free living conditions, however, it is more common to consume protein dense foods in single portions. Currently, there is no information available on how eating protein rich foods affects muscle protein synthesis in overweight and obese adults. This proposed research will fill this research gap by being the first study to compare the muscle protein synthetic response to the ingestion of a meal-like amount of high quality protein in lean, overweight and obese adults. The objective of this study is to determine the muscle protein synthetic response after the consumption of 35g pork protein in lean, overweight and obese adults. In order to assess this objective the researchers propose to use primed continuous infusion of L-[ring-13C6] phenylalanine to measure muscle protein synthesis rates after the consumption of dietary protein. In a parallel design the researchers will study 13 obese (BMI 30-39.9 kg/m2) participants, 13 overweight (BMI 25-29.9 kg/m2), and 13 age-matched lean controls (BMI 18-24.9 kg/m2) between the ages of 20 and 45 years. All subjects will be sedentary and weight stable for the previous 6 months. On the test day, subjects will remain sedentary for the determination of muscle protein synthesis in both the fasted state and after consumption of the protein meal. Blood and muscle sampling will occur on the test day.

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

Participants will be asked to report to the laboratory at 7:00 am following an overnight fast. Upon arrival, a Teflon catheter will be inserted in an antecubital vein of one arm for arterialized blood sampling and a baseline blood sample will be drawn. Arterialized blood samples will be obtained by wrapping the subjects' forearm in a heating blanket (45 °C) for 10 min prior to each blood collection time point. A second Teflon catheter will be inserted in an antecubital vein of the opposite arm, and participants will receive a priming dose of L-[ring- 13C6]phenylalanine (2.0 µmol∙kg) prior to initiating a continuous infusion of L-[ring-13C6]phenylalanine (0.05 µmol∙kg∙min) (t=-240). The prime and continuous tracer infusion will be passed through a 0.2 μm filter. Blood will be collected every 1 hour and biopsies of the vastus lateralis will be collected at t=-180 and t=-15 min using a 5 mm Bergström needle (modified for manual suction) under 2% xylocaine local anesthesia for the measurement of postabsorptive muscle protein synthesis rates. The second biopsy (t=-15 min) will be used to determine baseline levels of phosphorylated and total proteins involved in nutrient sensing and muscle anabolic signaling. Subsequently, the participants will ingest 6 oz of fresh ground center cut pork loin. This cut of meat was selected due to its low lipid content (2.5-3%) and it is uniform in shape, size and composition. Along with the ingested pork, the participants will consume 300 mL of water. The water will be enriched to 5% with tracer according to the phenylalanine content of ~4% in the pork. This approach is required to minimize disturbances in isotopic steady state and provide appropriate conditions for the calculation of postprandial muscle protein synthesis rates. The time required to consume the pork will be recorded. The completion of the pork meal and water will mark the start of the postprandial phase (t=0). During this period, arterialized blood samples will be collected into evacuated chilled heparinized tubes at t=30, 60, 90, 120, 180, 240, and 300 min. Additional muscle biopsies will be collected at t=120 and 300 min of the experimental infusion for the measurement of postprandial muscle protein synthetic and muscle anabolic signaling protein responses. The muscle biopsy samples will be freed from any visible blood, fat, and connective tissue, rapidly frozen in liquid nitrogen and stored at -80˚C until analysis. Blood samples will be centrifuged at 1,000×g at 4˚C for 10 min and separated plasma will be transferred to 2.0 ml cryovials. The plasma samples will be stored at -20˚C until further analysis.

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.
32

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

20 years to 45 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

We recruited 32 healthy, sedentary adult subjects (20-45 y) for this investigation. There are three groups being studied, which will be stratified by body mass index. Because randomization is not possible, groups were balanced by age and sex. No races or ethnic groups will be specifically recruited or excluded.

Description

Inclusion Criteria:

  • Males and Females
  • Aged between 20-45 years
  • Healthy, sedentary
  • Three groups, age and sex matched
  • Healthy weight group: BMI 18-24.9 kg/m2
  • Overweight group: BMI 25-29.9 kg/m2
  • Obese group: BMI 30-39.9 kg/m2

Exclusion Criteria:

  • Smoking
  • Allergies to pork consumption
  • Unusually high protein consumption
  • Vegetarians
  • Phenylketonuria (PKU)
  • Diagnosed GI tract diseases
  • Arthritic conditions
  • A history of neuromuscular problems
  • Previous participation in amino acid tracer studies
  • Predisposition to hypertrophic scarring or keloid formation
  • Individuals on any medications known to affect protein metabolism (i.e. corticosteroids, non-steroidal anti-inflammatories, or prescription strength acne medications).
  • Irregular menstrual cycles during the previous year
  • Pregnancy
  • High BMI that is not representative of being overweight or obese (e.g. resistance trained individuals, football players)

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

  • Observational Models: Cohort
  • Time Perspectives: Prospective

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.
Obese

BMI >30 kg/m2, Protein meal,

L-[ring 13C6]Phenylalanine infusion
Other: Protein meal
Ingestion of protein
Other: L-[ring 13C6]Phenylalanine infusion
experimental method for determining protein synthesis rates
Overweight

BMI >25 and < 30 kg/m2, Protein meal,

L-[ring 13C6]Phenylalanine infusion
Other: Protein meal
Ingestion of protein
Other: L-[ring 13C6]Phenylalanine infusion
experimental method for determining protein synthesis rates
Healthy-Weight

BMI >18 and < 25 kg/m2, Protein meal,

L-[ring 13C6]Phenylalanine infusion
Other: Protein meal
Ingestion of protein
Other: L-[ring 13C6]Phenylalanine infusion
experimental method for determining protein synthesis rates

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
Time Frame
Fractional synthetic rate of myofibrillar proteins
Time Frame: 7 hours
7 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.
University of Illinois at Urbana-Champaign

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: Nicholas A Burd, Ph.D, Assistant Professor

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

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, 2014

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.
September 1, 2015

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.
August 1, 2016

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).
November 5, 2015

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.
November 20, 2015

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.
November 24, 2015

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.
October 26, 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.
October 24, 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.
October 1, 2016

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.
  • 15161 (Other Identifier: City of Hope Medical Center)

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