Clinical trial NCT00690534: Insulin and Sarcopenia in the Elderly
Official title: Insulin and Sarcopenia in the Elderly
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE1
Conditions: Sarcopenia
Keywords: sarcopenia
aging
muscle metabolism
Lead sponsor: The University of Texas Medical Branch, Galveston
Sponsor class: OTHER
Collaborators: name: National Institute on Aging (NIA)
First posted: 2008-06-04
Enrollment: 88
Sex: ALL
Minimum age (years): 18
Maximum age (years): 85
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: BASIC_SCIENCE

Brief summary: Muscle loss with aging is a significant contributor to disability in older people. Our general hypothesis is that loss of muscle with aging, known as sarcopenia, may be due to inability of muscle to grow in response to insulin. Our goal is to determine the mechanisms underlying this age-related insulin resistance of muscle proteins, which will allow us to define in the future specific interventions to target this defect and provide the scientific basis for the prevention and treatment of sarcopenia.

Detailed description: Our general hypothesis is that a reduced response of muscle protein anabolism to insulin plays an important role in the loss of muscle mass with aging. Our goal is to determine the mechanisms underlying the age-related insulin resistance of muscle proteins, which will allow us to define specific interventions to target this defect and provide the scientific basis for the prevention and treatment of sarcopenia.

Our previous studies indicate that the response of muscle proteins to the anabolic action of insulin is impaired in healthy older adults as compared to younger controls, which hampers the anabolic effect of mixed feeding on muscle proteins. These changes are associated with an age-related reduction in the vasodilatory response to insulin, which, from our data, appears to be a potentially important mediator of the physiological anabolic effect of insulin on muscle proteins. Preliminary data from our laboratory also suggest that in older subjects a single bout of aerobic exercise may restore the normal response of blood flow, muscle protein synthesis and anabolism to insulin.

Therefore, we will test in healthy subjects the following specific hypotheses:

1. Insulin-induced increases in blood flow and muscle perfusion are necessary for the physiological stimulation of muscle protein synthesis and anabolism by insulin.
2. Aging reduces the vascular sensitivity to insulin, which prevents the physiological increase in blood flow and muscle perfusion in response to insulin, thereby decreasing the response of muscle protein synthesis and net balance to the anabolic action of insulin and mixed feeding.
3. Aerobic exercise can restore, in older subjects, the insulin-induced increase in blood flow and muscle perfusion to youthful levels, thus normalizing the anabolic effect of insulin and mixed feeding on muscle protein synthesis and net muscle protein balance.

We will use state-of the art stable isotope tracer techniques to measure muscle protein turnover, and a newly developed method to measure muscle perfusion in young and older subjects. The results of these studies will allow us to better define the physiological mechanisms of action of insulin on muscle protein anabolism, advance our knowledge on the pathophysiology of sarcopenia, and provide the scientific basis for the behavioral and/or pharmacological treatment of muscle loss with aging.

Eligibility criteria: Inclusion Criteria:

1. Age 18-40 yrs, and 65-85 yrs.
2. Ability to sign consent form (score \>23 on the 30-item Mini Mental State Examination, MMSE)
3. Stable body weight for at least 3 months

Exclusion Criteria:

1. Physical dependence or frailty (impairment in any of the Activities of Daily Living (ADL), history of falls (\>2/year) or significant weight loss in the past year)
2. Exercise training (\>2 weekly sessions of moderate to high intensity aerobic or resistance exercise)
3. Pregnancy or nursing women.
4. Significant heart, liver, kidney, blood or respiratory disease
5. Peripheral vascular disease
6. Diabetes mellitus or other untreated endocrine disease
7. Active cancer
8. Recent (within 6 months) treatment with anabolic steroids, or corticosteroids.
9. Alcohol or drug abuse
10. Severe depression (\>5 on the 15-item Geriatric Depression Scale, GDS)
11. Potential subjects who have recently donated blood in the past 60 days will be excluded from participating in the study.

Primary outcomes:
measure: muscle protein synthesis
timeFrame: 5 and 8 hours
Secondary outcomes:
measure: blood flow
timeFrame: 5 and 8 hours
Other outcomes:
Locations:
city: Galveston
country: United States
facility: Sealy Center on Aging, University of Texas Medical Branch
state: Texas
Study officials:
affiliation: The University of Texas Medical Branch at Galveston
name: Elena Volpi, MD, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Rasmussen BB, Fujita S, Wolfe RR, Mittendorfer B, Roy M, Rowe VL, Volpi E. Insulin resistance of muscle protein metabolism in aging. FASEB J. 2006 Apr;20(6):768-9. doi: 10.1096/fj.05-4607fje. Epub 2006 Feb 7.
citation: Bell JA, Volpi E, Fujita S, Cadenas JG, Sheffield-Moore M, Rasmussen BB. Skeletal muscle protein anabolic response to increased energy and insulin is preserved in poorly controlled type 2 diabetes. J Nutr. 2006 May;136(5):1249-55. doi: 10.1093/jn/136.5.1249.
citation: Bell JA, Volpi E, Fujita S, Cadenas JG, Rasmussen BB. Dysregulation of muscle fatty acid metabolism in type 2 diabetes is independent of malonyl-CoA. Diabetologia. 2006 Sep;49(9):2144-52. doi: 10.1007/s00125-006-0362-9. Epub 2006 Jul 26.
citation: Timmerman KL, Volpi E. Amino acid metabolism and regulatory effects in aging. Curr Opin Clin Nutr Metab Care. 2008 Jan;11(1):45-9. doi: 10.1097/MCO.0b013e3282f2a592.
citation: Fujita S, Volpi E. Amino acids and muscle loss with aging. J Nutr. 2006 Jan;136(1 Suppl):277S-80S. doi: 10.1093/jn/136.1.277S.
citation: Dreyer HC, Volpi E. Role of protein and amino acids in the pathophysiology and treatment of sarcopenia. J Am Coll Nutr. 2005 Apr;24(2):140S-145S. doi: 10.1080/07315724.2005.10719455.
citation: Drummond MJ, Bell JA, Fujita S, Dreyer HC, Glynn EL, Volpi E, Rasmussen BB. Amino acids are necessary for the insulin-induced activation of mTOR/S6K1 signaling and protein synthesis in healthy and insulin resistant human skeletal muscle. Clin Nutr. 2008 Jun;27(3):447-56. doi: 10.1016/j.clnu.2008.01.012. Epub 2008 Mar 14.
citation: Drummond MJ, Dreyer HC, Pennings B, Fry CS, Dhanani S, Dillon EL, Sheffield-Moore M, Volpi E, Rasmussen BB. Skeletal muscle protein anabolic response to resistance exercise and essential amino acids is delayed with aging. J Appl Physiol (1985). 2008 May;104(5):1452-61. doi: 10.1152/japplphysiol.00021.2008. Epub 2008 Mar 6.
citation: Fujita S, Rasmussen BB, Cadenas JG, Drummond MJ, Glynn EL, Sattler FR, Volpi E. Aerobic exercise overcomes the age-related insulin resistance of muscle protein metabolism by improving endothelial function and Akt/mammalian target of rapamycin signaling. Diabetes. 2007 Jun;56(6):1615-22. doi: 10.2337/db06-1566. Epub 2007 Mar 9.
citation: Fujita S, Rasmussen BB, Bell JA, Cadenas JG, Volpi E. Basal muscle intracellular amino acid kinetics in women and men. Am J Physiol Endocrinol Metab. 2007 Jan;292(1):E77-83. doi: 10.1152/ajpendo.00173.2006. Epub 2006 Aug 8.
citation: Fujita S, Rasmussen BB, Cadenas JG, Grady JJ, Volpi E. Effect of insulin on human skeletal muscle protein synthesis is modulated by insulin-induced changes in muscle blood flow and amino acid availability. Am J Physiol Endocrinol Metab. 2006 Oct;291(4):E745-54. doi: 10.1152/ajpendo.00271.2005. Epub 2006 May 16.
citation: Bell JA, Fujita S, Volpi E, Cadenas JG, Rasmussen BB. Short-term insulin and nutritional energy provision do not stimulate muscle protein synthesis if blood amino acid availability decreases. Am J Physiol Endocrinol Metab. 2005 Dec;289(6):E999-1006. doi: 10.1152/ajpendo.00170.2005. Epub 2005 Jul 19.
citation: Volpi E, Chinkes DL, Rasmussen BB. Sequential muscle biopsies during a 6-h tracer infusion do not affect human mixed muscle protein synthesis and muscle phenylalanine kinetics. Am J Physiol Endocrinol Metab. 2008 Oct;295(4):E959-63. doi: 10.1152/ajpendo.00671.2007. Epub 2008 Aug 19.
citation: Drummond MJ, Miyazaki M, Dreyer HC, Pennings B, Dhanani S, Volpi E, Esser KA, Rasmussen BB. Expression of growth-related genes in young and older human skeletal muscle following an acute stimulation of protein synthesis. J Appl Physiol (1985). 2009 Apr;106(4):1403-11. doi: 10.1152/japplphysiol.90842.2008. Epub 2008 Sep 11.
citation: Fujita S, Glynn EL, Timmerman KL, Rasmussen BB, Volpi E. Supraphysiological hyperinsulinaemia is necessary to stimulate skeletal muscle protein anabolism in older adults: evidence of a true age-related insulin resistance of muscle protein metabolism. Diabetologia. 2009 Sep;52(9):1889-98. doi: 10.1007/s00125-009-1430-8. Epub 2009 Jul 9.
citation: Timmerman KL, Lee JL, Dreyer HC, Dhanani S, Glynn EL, Fry CS, Drummond MJ, Sheffield-Moore M, Rasmussen BB, Volpi E. Insulin stimulates human skeletal muscle protein synthesis via an indirect mechanism involving endothelial-dependent vasodilation and mammalian target of rapamycin complex 1 signaling. J Clin Endocrinol Metab. 2010 Aug;95(8):3848-57. doi: 10.1210/jc.2009-2696. Epub 2010 May 19.
citation: Timmerman KL, Lee JL, Fujita S, Dhanani S, Dreyer HC, Fry CS, Drummond MJ, Sheffield-Moore M, Rasmussen BB, Volpi E. Pharmacological vasodilation improves insulin-stimulated muscle protein anabolism but not glucose utilization in older adults. Diabetes. 2010 Nov;59(11):2764-71. doi: 10.2337/db10-0415. Epub 2010 Aug 19.
citation: Drummond MJ, McCarthy JJ, Sinha M, Spratt HM, Volpi E, Esser KA, Rasmussen BB. Aging and microRNA expression in human skeletal muscle: a microarray and bioinformatics analysis. Physiol Genomics. 2011 May 1;43(10):595-603. doi: 10.1152/physiolgenomics.00148.2010. Epub 2010 Sep 28.
citation: Timmerman KL, Dhanani S, Glynn EL, Fry CS, Drummond MJ, Jennings K, Rasmussen BB, Volpi E. A moderate acute increase in physical activity enhances nutritive flow and the muscle protein anabolic response to mixed nutrient intake in older adults. Am J Clin Nutr. 2012 Jun;95(6):1403-12. doi: 10.3945/ajcn.111.020800. Epub 2012 May 9.
citation: Drummond MJ, Dickinson JM, Fry CS, Walker DK, Gundermann DM, Reidy PT, Timmerman KL, Markofski MM, Paddon-Jones D, Rasmussen BB, Volpi E. Bed rest impairs skeletal muscle amino acid transporter expression, mTORC1 signaling, and protein synthesis in response to essential amino acids in older adults. Am J Physiol Endocrinol Metab. 2012 May 15;302(9):E1113-22. doi: 10.1152/ajpendo.00603.2011. Epub 2012 Feb 14.
citation: Drummond MJ, Timmerman KL, Markofski MM, Walker DK, Dickinson JM, Jamaluddin M, Brasier AR, Rasmussen BB, Volpi E. Short-term bed rest increases TLR4 and IL-6 expression in skeletal muscle of older adults. Am J Physiol Regul Integr Comp Physiol. 2013 Aug 1;305(3):R216-23. doi: 10.1152/ajpregu.00072.2013. Epub 2013 Jun 12.