Muscle Mass During Space Exploration

Muscle Loss Clinical Trial

Official title:

An Integrated Low-Volume Nutritional Countermeasure to Maintain Muscle Mass and Function During Space Exploration

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00968344
• Other study ID #: 09-121
• Secondary ID: MA02001
• Status: Completed
• Phase: N/A
• Start date: August 2009
• Est. completion date: April 2015

Study information

• Verified date: December 2017
• Source: The University of Texas Medical Branch, Galveston
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

The investigators will test the following hypotheses:

1. Bedrest will blunt the anabolic response to a mixed nutrient meal, facilitating a loss of muscle mass and functional capacity that is only partially restored during rehabilitation.

2. Enriching daily meals with leucine will promote protein synthesis and maintain the anabolic response to mixed nutrient meal ingestion. This will preserve lean muscle mass and function during bedrest and facilitate the recovery of functional and metabolic capacity during rehabilitation.

Description:

Our long-term goal is to identify, prevent and remedy defects in the metabolic pathway that contribute to the loss of muscle mass and function during exposure to microgravity. Demographic data indicate that the average age of shuttle crew members has increased from 40.7 yrs in 1995 to 46.7 yrs in 2007 with an increasing number of astronauts over 50 yrs of age. We contend that the loss of muscle mass and function during spaceflight is facilitated by an age-associated, progressive impairment in the ability to mount an anabolic response to standard mixed nutrient meals. We propose that enriching daily meals with a low-volume leucine supplement will reduce the deleterious effects of microgravity on skeletal muscle and facilitate recovery during rehabilitation.

We will employ our established 14 day bed rest protocol to model the skeletal muscle unloading that occurs during microgravity. We will also examine recovery of muscle mass and functional capacity during a 7 day rehabilitation period. We will study 2 groups: CON (Bedrest/Recovery + Placebo; n=15), LEU (Bedrest/Recovery + Leucine; n=15). We will assess a) markers of translation initiation, b) muscle protein synthesis, c) muscle mass and body composition and d) strength and aerobic capacity.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 40
• Est. completion date: April 2015
• Est. primary completion date: April 2015
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 45 Years to 60 Years

Eligibility

Inclusion Criteria:

1. Age between 45-60

2. Ability to sign informed consent

Exclusion Criteria:

1. Subjects with cardiac abnormalities considered exclusionary by the study physicians

2. Subjects with uncontrolled metabolic disease

3. A GFR <65 mL/min/1.73m2 or evidence of kidney disease or failure

4. Subjects with vascular disease or risk factors of peripheral atherosclerosis

5. Any history of hypo- or hyper-coagulation disorders. (e.g., Coumadin use or history of DVT or PE)

6. Subjects with chronically elevated systolic pressure >150 or a diastolic blood pressure > 100

7. Subjects with implanted electronic devices (e.g., pacemakers, electronic infusion pumps, stimulators)

8. Subjects with recently (6 months) treated cancer other than basal cell carcinoma

9. Any subject currently on a weight-loss diet or a body mass index > 30 kg/m2

10. Inability to abstain from smoking for duration of study

11. A history of > 20 pack per year smoking

12. Any subject that is HIV-seropositive or has active hepatitis

13. Recent anabolic or corticosteroids use (within 3 months)

14. Subjects with hemoglobin or hematocrit lower than accepted lab values

15. Agitation/aggression disorder

16. History of stroke with motor disability

17. A recent history (<12 months) of GI bleed

18. Any other condition or event considered exclusionary by the PI and faculty physician

Related Conditions & MeSH terms

• Muscle Loss

Intervention

Dietary Supplement:
• Leucine
3-4g Leucine added to daily meals
• Alanine
Powered amino acid

Locations

Country	Name	City	State
United States	The University of Texas Medical Branch	Galveston	Texas

Sponsors (2)

Lead Sponsor	Collaborator
The University of Texas Medical Branch, Galveston	National Space Biomedical Research Institute

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Lean Leg Mass	DEXA scan of both legs pre/post bed rest	At baseline prior to beginning bed rest and after 14 days of bed rest