Format

Send to

Choose Destination
Ann Nucl Med. 2017 May;31(4):295-303. doi: 10.1007/s12149-017-1157-4. Epub 2017 Mar 4.

11C-L-methyl methionine dynamic PET/CT of skeletal muscle: response to protein supplementation compared to L-[ring 13C6] phenylalanine infusion with serial muscle biopsy.

Author information

1
Department of Nutrition and Metabolism and Center for Recovery, Physical Activity and Nutrition (CeRPAN), University of Texas Medical Branch, Galveston, 77573, USA.
2
Department of Radiology and Biomedical Imaging, University of California, San Francisco, Box 0946, San Francisco, CA, 94143-0946, USA.
3
Department of Medicine, University of California, San Francisco, San Francisco, CA, 94143, USA.
4
Department of Radiology and Biomedical Imaging, University of California, San Francisco, Box 0946, San Francisco, CA, 94143-0946, USA. thomas.lang@ucsf.edu.

Abstract

OBJECTIVE:

The objective of this study was to determine if clinical dynamic PET/CT imaging with 11C-L-methyl-methionine (11C-MET) in healthy older women can provide an estimate of tissue-level post-absorptive and post-prandial skeletal muscle protein synthesis that is consistent with the more traditional method of calculating fractional synthesis rate (FSR) of muscle protein synthesis from skeletal muscle biopsies obtained during an infusion of L-[ring 13C6] phenylalanine (13C6-Phe).

METHODS:

Healthy older women (73 ± 5 years) completed both dynamic PET/CT imaging with 11C-MET and a stable isotope infusion of 13C6-Phe with biopsies to measure the skeletal muscle protein synthetic response to 25 g of a whey protein supplement. Graphical estimation of the Patlak coefficient Ki from analysis of the dynamic PET/CT images was employed as a measure of incorporation of 11 C-MET in the mid-thigh muscle bundle.

RESULTS:

Post-prandial values [mean ± standard error of the mean (SEM)] were higher than post-absorptive values for both Ki (0.0095 ± 0.001 vs. 0.00785 ± 0.001 min-1, p < 0.05) and FSR (0.083 ± 0.008 vs. 0.049 ± 0.006%/h, p < 0.001) in response to the whey protein supplement. The percent increase in Ki and FSR in response to the whey protein supplement was significantly correlated (r = 0.79, p = 0.015).

CONCLUSIONS:

Dynamic PET/CT imaging with 11C-MET provides an estimate of the post-prandial anabolic response that is consistent with a traditional, invasive stable isotope, and muscle biopsy approach. These results support the potential future use of 11C-MET imaging as a non-invasive method for assessing conditions affecting skeletal muscle protein synthesis.

KEYWORDS:

FSR; Human; Muscle protein synthesis; PET/CT

PMID:
28260185
PMCID:
PMC5397459
DOI:
10.1007/s12149-017-1157-4
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Springer Icon for PubMed Central
Loading ...
Support Center