Procollagen type III N-terminal peptide (P3NP) and lean mass: a cross-sectional study.
BACKGROUND
Procollagen type III N-terminal peptide (P3NP) is released during collagen synthesis in muscle. Increased circulating P3NP is a marker not only of muscle growth, but also of muscle repair and fibrosis. Thus, P3NP may be a potential biomarker for sarcopenia.


OBJECTIVE
To determine the association between plasma P3NP and lean mass and strength.


METHODS
A cross-sectional study of men and women from the Framingham Offspring Study. Participants included a convenience sample of 687 members with a measure of plasma P3NP and lean mass, and 806 members with P3NP and quadriceps strength assessment.


METHODS
Linear regression was used to estimate the association between total and appendicular lean mass and plasma P3NP, and quadriceps strength and P3NP.


RESULTS
Mean age was 58 years. Median plasma P3NP was similar in men (3.4 mg/L), premenopausal women (3.1 mg/L), and postmenopausal women (3.0 mg/L). In adjusted models, higher P3NP was associated with a modest decrease in total and appendicular lean mass in postmenopausal women [β= -0.13 unit P3NP/kg total lean mass; p=0.003]. A similar trend was found among premenopausal women, although results were not statistically significant [β=-0.10 unit P3NP/kg total lean mass; p=0.41]. No association between P3NP and lean mass was observed in men. P3NP was not associated with strength in men or women.


CONCLUSIONS
Our results suggest that plasma P3NP might be a useful biomarker of muscle mass in postmenopausal women if longitudinal studies demonstrate that it has adequate sensitivity and specificity to predict muscle loss.
Hebrew SeniorLife, Institute for Aging Research & Harvard Medical School, 1200 Centre Street, Boston, MA 02131. (SDB, RRM, DPK); Boston University School of Medicine, 671 Harrison Avenue, Harrison Court B06, Boston, MA 02118. (RSV, LAC); Boston University, Department of Mathematics and Statistics, 111 Cummington St., Boston, MA 02115 (PG); NHLBI Framingham Heart Study (PG); California Pacific Medical Center Research Institute, Suite 5700, 185 Berry Street, San Francisco, CA 94107. (PC).
Sarah D
SD
Berry
Vasan S
VS
Ramachandran
Peggy M
PM
Cawthon
Philimon
P
Gona
Robert R
RR
McLean
L Adrienne
LA
Cupples
Douglas P
DP
Kiel
P3NP; lean mass; procollagen type III N-telopeptide