Muscle weakness during aging: a deficiency state involving declining angiogenesis

• There are 37 reports of reduced capillary density in aged people & animals.
• There are 11 reports of diminished levels of angiogenic factors in aged people & animals.
• Muscle weakness & cognitive impairment may result from these related conditions.
• Reduced levels of certain hormones & stem cells may act through angiogenesis, leading to sarcopenia.
• Recombinant angiogenic factors may be used in therapeutic angiogenesis.
• Therapeutic angiogenesis may delay onset of the lesser ailments & senile dementias.

This essay begins by proposing that muscle weakness of old age from sarcopenia is due in large part to reduced capillary density in the muscles, as documented in 9 reports of aged persons and animals. Capillary density (CD) is determined by local levels of various angiogenic factors, which also decline in muscles with aging, as reported in 7 studies of old persons and animals. There are also numerous reports of reduced CD in the aged brain and other studies showing reduced CD in the kidney and heart of aged animals. Thus a waning angiogenesis throughout the body may be a natural occurrence in later years and may account significantly for the lesser ailments (physical and cognitive) of elderly people. Old age is regarded here as a deficiency state which may be corrected by therapeutic angiogenesis, much as a hormonal deficiency can be relieved by the appropriate hormone therapy. Such therapy could employ recombinant angiogenic factors which are now commercially available.