Viewpoint on the role of tissue maintenance in ageing: focus on biomarkers of bone, cartilage, muscle, and brain tissue maintenance

•Hypothesis: tissue maintenance are at the interface between specific hallmarks of ageing and disease.•Biomarkers of tissue maintenance might represent a novel category of biomarkers of ageing.•Established biomarkers are available for bone tissue maintenance.•Potential biomarkers for cartilage and muscle tissue maintenance are available.•No suitable biomarkers of brain tissue maintenance are currently available.