title: Effect of aging on expression of angiogenesis-related factors in mouse skeletal muscle.
abstract: The molecular mechanisms by which capillary supply is maintained with advancing age remain to be elucidated. To help clarify these mechanisms, we investigated the gene expression levels of angiogenesis-related factors in young (2.5-month-old), adult (6-month-old), and old (22-month-old) mice. To assess the capillary supply, the capillary endothelium in frozen transverse sections was identified by staining for alkaline phosphatase. The mRNA levels for angiogenesis-related factors were analyzed using real-time RT-PCR. The capillary supply to individual muscle fibers, assessed as the number of capillaries around a muscle fiber, did not change with advancing age. Real-time RT-PCR analysis showed that (1) the level of mRNA for VEGF was lower in old animals than young animals; (2) the mRNA levels of Flt-1 and neuropilin-1 are lower in old animals than young animals, while that of KDR/Flk-1 remained unchanged with advancing age; and (3) the levels of mRNA for angiopoietin-1 and -2 remained unchanged, while the mRNA for Tie-2 was lower in old animals than young animals. These findings suggest that capillary supply is maintained irrespective of the down-regulation of several angiogenesis-related factors and that old animals possess the minimum levels of maintenance and reparative abilities needed to preserve the capillary supply.
authors.affiliation: Department of Biochemical Sciences, National Institute of Fitness and Sports, Shiromizu-cho 1, Kanoya, Kagoshima 891-2393, Japan. waga@nifs-k.ac.jp
authors.forename: A
authors.initials: A
authors.lastname: Wagatsuma
mesh_terms: D000375:Aging / Q000378:metabolism*; D042501:Angiogenic Proteins / Q000096:biosynthesis* / Q000235:genetics; D042682:Angiopoietins / Q000096:biosynthesis / Q000235:genetics; D000818:Animals; D001835:Body Weight; D002196:Capillaries / Q000033:anatomy & histology; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000098:blood supply / Q000378:metabolism*; D009929:Organ Size; D012333:RNA, Messenger / Q000235:genetics; D042787:Receptor, TIE-2 / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000235:genetics; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000096:biosynthesis / Q000235:genetics
chemical_list: D042501:Angiogenic Proteins; D042682:Angiopoietins; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D042787:Receptor, TIE-2; D040301:Vascular Endothelial Growth Factor Receptor-2