Age-related Delays in Osteochondral Remodeling of Fracture Healing Illustrated by Mass Spectrometry Imaging

ABSTRACT: Age-related delays in fracture healing are prevalent and contribute to morbidity and mortality in elderly populations. Clinical and preclinical studies demonstrate that aging is associated with slower and less complete fracture repair characterized by delayed cartilage and bone formation, impaired matrix resorption, and an increased risk of delayed union or nonunion. Matrix Assisted Laser Desorption Ionization Mass Spectrometry Imaging (MALDI MSI) enables spatially resolved, in situ molecular analysis of proteins directly from murine fracture tissue sections. We applied collagenase type III (MMP 13) mediated proteolytic digestion to formalin fixed, paraffin embedded (FFPE) tibia fracture callus sections harvested 10 days post tibial fracture from young (3 month old) and aged (18 month old) mice to perform spatially resolved proteomic profiling. MALDI MSI revealed pronounced age dependent differences in extracellular matrix protein composition and remodeling within the fracture callus. We identified up regulation of canonical bone and matrix proteins, including Col1a1 and Col1a2 specifically in the young fracture callus demonstrating advancement into harden callus formation. Conversely, Col2a1 and other soft callus proteins were only seen in the aged callus tissues. Further, protein indicators of tissue state, such as fibronectin (up regulated) and calreticulin (down regulated) were selectively regulated aged tissues, demonstrating a failure for aged tissues to fully progress into harden calluses. Spatial proteomic patterns demonstrated a marked delay in progression from cartilaginous to osseous callus in aged mice, consistent with impaired matrix remodeling during fracture repair. Together, these findings establish MALDI MSI based spatial proteomics as a powerful approach to elucidate age related alterations in fracture healing and to identify molecular regulators of impaired skeletal regeneration.

INSTRUMENT(S): timsTOF fleX

ORGANISM(S): Mus Musculus (ncbitaxon:10090)

SUBMITTER: Birgit Schilling  

PROVIDER: MSV000100309 | MassIVE | Mon Dec 22 13:51:00 GMT 2025

SECONDARY ACCESSION(S): PXD072311

REPOSITORIES: MassIVE