Serum levels of C-terminal agrin fragment (CAF) are associated with sarcopenia in older multimorbid community-dwellers: Results from the ilSIRENTE study

Abstract

Background: The C-terminal agrin fragment (CAF), a circulating byproduct of neuromuscular junction disassembly, has been proposed as a possible biomarker for sarcopenia. However, its validity in "real-world", multimorbid older persons is currently unknown. The present study was undertaken to verify if serum CAF levels were associated with sarcopenia in a population of old and very old persons living in the community.

Methods: Data were from the ilSIRENTE Aging and Longevity Study, a prospective cohort study conducted in all persons aged 80years and older residing in the Sirente geographic area (Italy; n=332). The identification of sarcopenia was based on the criteria elaborated by the European Working Group on Sarcopenia in Older People (EWGSOP). Serum levels of CAF were determined using a commercial ELISA kit.

Results: Sarcopenia was identified in 101 participants (30.8%). Serum levels of CAF were significantly higher in older adults with sarcopenia compared with non-sarcopenic participants (96.99±5.40pmol/L vs. 76.54±2.15pmol/L; p<0.001). The association remained significant in both genders after adjustment for several possible confounding factors, including age, cognition, disability status, body mass index, congestive heart failure, lung diseases, diabetes, renal failure, and plasma levels of C-reactive protein and interleukin 6.

Conclusions: Our results obtained from a fairly large sample of old and very old, multimorbid community-dwellers show that elevated serum CAF levels are associated with sarcopenia, independent of age, gender and several clinical, functional, anthropometric, and biochemical variables. The determination of serum CAF concentration may therefore be proposed as a simple screening test for sarcopenia in the community.

Keywords: Aging; Anthropometry; Biomarkers; Co-morbidity; Frailty; Functional impairment; Gait speed; Handgrip; Mid-arm muscle circumference; Muscle wasting; Neuromuscular junction; Physical performance; Renal failure; Skeletal muscle.