Open AccessIsotopic decay of urinary or plasma 3‐methylhistidine as a potential biomarker of pathologic skeletal muscle loss
Author(s) -
Sheffield-Moore M.,
Dillon E. L.,
Randolph K. M.,
Casperson S. L.,
White G. R.,
Jennings K.,
Rathmacher J.,
Schuette S.,
Janghorbani M.,
Urban R. J.,
Hoang V.,
Willis M.,
Durham W. J.
Publication year - 2014
Publication title -
journal of cachexia, sarcopenia and muscle
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.803
H-Index - 66
eISSN - 2190-6009
pISSN - 2190-5991
DOI - 10.1007/s13539-013-0117-7
Subject(s) - urine , isotope , chemistry , biomarker , skeletal muscle , urinary system , blood sampling , tracer , endocrinology , medicine , biochemistry , physics , quantum mechanics , nuclear physics
Background Skeletal muscle loss accompanying aging or cancer is associated with reduced physical function and predicts morbidity and mortality. 3‐Methylhistidine (3MH) has been proposed as a biomarker of myofibrillar proteolysis, which may contribute to skeletal muscle loss. Methods We hypothesized that the terminal portion of the isotope decay curve following an oral dose of isotopically labeled 3MH can be measured non‐invasively from timed spot urine samples. We investigated the feasibility of this approach by determining isotope enrichment in spot urine samples and corresponding plasma samples and whether meat intake up to the time of dosing influences the isotope decay. Results Isotope decay constants ( k ) were similar in plasma and urine, regardless of diet. Post hoc comparison of hourly sampling over 10 h with three samples distributed over 10 or fewer hours suggests that three distributed samples over 5–6 h of plasma or urine sampling yield decay constants similar to those obtained over 10 h of hourly sampling. Conclusion The findings from this study suggest that an index of 3MH production can be obtained from an easily administered test involving oral administration of a stable isotope tracer of 3MH followed by three plasma or urine samples collected over 5–6 h the next day.