Fluorophores from aging human articular cartilage

Area of Science:

• Biochemistry
• Biomaterials Science
• Aging Research

Background:

• Collagen is a key structural protein in articular cartilage.
• Collagen undergoes cross-linking with age, affecting tissue properties.
• Identifying age-related changes in collagen cross-links is crucial for understanding cartilage aging.

Purpose of the Study:

• To investigate the age-dependent changes of specific collagen cross-links in human articular cartilage.
• To quantify and characterize pyridinoline and pentosidine in relation to age.

Main Methods:

• Human articular cartilage from various ages was digested using collagenase.
• Fluorescence spectroscopy was employed to measure and identify fluorophores.
• Isolation and structural elucidation of identified fluorophores were performed.
• Quantification of pyridinoline and pentosidine per collagen was correlated with age.

Main Results:

• Two main fluorophores, pyridinoline and pentosidine, were identified in collagenase digests.
• Pentosidine content per collagen increased linearly with age (r = 0.929, p < 0.005).
• Pyridinoline content per collagen remained constant and showed no correlation with age (r = 0.20).
• The ratio of pentosidine to pyridinoline increased exponentially with age (r^2 = 0.839, p < 0.05).

Conclusions:

• Pentosidine accumulation is a significant age-related modification in human articular cartilage collagen.
• Pyridinoline levels are stable and not indicative of cartilage aging.
• The exponential increase in the pentosidine/pyridinoline ratio highlights pentosidine's role in the aging process of articular cartilage.