What old means to bone.
The adverse effects of aging of other organs (ovaries at menopause) on the skeleton are well known, but ironically little is known of skeletal aging itself. Evidence indicates that age-related changes, such as oxidative stress, are fundamental mechanisms of the decline of bone mass and strength. Unlike the short-lived osteoclasts and osteoblasts, osteocytes--former osteoblasts entombed in the mineralized matrix--live as long as 50 years, and their death is dependent on skeletal age. Osteocyte death is a major contributor to the decline of bone strength with age, and the likely mechanisms are oxidative stress, autophagy failure and nuclear pore "leakiness". Unraveling these mechanisms should improve understanding of the age-related increase in fractures and suggest novel targets for its prevention.
Manolagas
Stavros C
SC
Division of Endocrinology and Metabolism, Center for Osteoporosis and Metabolic Bone Diseases, University of Arkansas for Medical Sciences and the Central Arkansas Veterans Health Care System, Little Rock, AR 72205, USA. manolagasstavros@uams.edu
Parfitt
A Michael
AM
D000375:Aging / Q000502:physiology*; D000818:Animals; D001847:Bone Diseases / Q000503:physiopathology; D001842:Bone and Bones / Q000502:physiology*; D016923:Cell Death / Q000502:physiology; D006801:Humans; D008593:Menopause / Q000502:physiology*; D010011:Osteocytes / Q000502:physiology*