Adrenomedullin enhances angiogenic potency of bone marrow transplantation in a rat model of hindlimb ischemia.
BACKGROUND
Previous studies have shown that adrenomedullin (AM) inhibits vascular endothelial cell apoptosis and induces angiogenesis. We investigated whether AM enhances bone marrow cell-induced angiogenesis.


RESULTS
Immediately after hindlimb ischemia was created, rats were randomized to receive AM infusion plus bone marrow-derived mononuclear cell (MNC) transplantation (AM+MNC group), AM infusion alone (AM group), MNC transplantation alone (MNC group), or vehicle infusion (control group). The laser Doppler perfusion index was significantly higher in the AM and MNC groups than in the control group (0.74+/-0.11 and 0.69+/-0.07 versus 0.59+/-0.07, respectively, P<0.01), which suggests the angiogenic potency of AM and MNC. Importantly, improvement in blood perfusion was marked in the AM+MNC group (0.84+/-0.08). Capillary density was highest in the AM+MNC group, followed by the AM and MNC groups. In vitro, AM inhibited MNC apoptosis, promoted MNC adhesiveness to a human umbilical vein endothelial cell monolayer, and increased the number of MNC-derived endothelial progenitor cells. In vivo, AM administration not only enhanced the differentiation of MNC into endothelial cells but also produced mature vessels that included smooth muscle cells.


CONCLUSIONS
A combination of AM infusion and MNC transplantation caused significantly greater improvement in hindlimb ischemia than MNC transplantation alone. This effect may be mediated in part by the angiogenic potency of AM itself and the beneficial effects of AM on the survival, adhesion, and differentiation of transplanted MNCs.
Iwase
Takashi
T
Department of Regenerative Medicine and Tissue Engineering, National Cardiovascular Center Research Institute, Suita, Osaka, Japan.
Nagaya
Noritoshi
N
Fujii
Takafumi
T
Itoh
Takefumi
T
Ishibashi-Ueda
Hatsue
H
Yamagishi
Masakazu
M
Miyatake
Kunio
K
Matsumoto
Toshio
T
Kitamura
Soichiro
S
Kangawa
Kenji
K
D053607:Adrenomedullin; D043925:Angiogenesis Inducing Agents / Q000627:therapeutic use*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D016026:Bone Marrow Transplantation; D002448:Cell Adhesion; D002454:Cell Differentiation; D002465:Cell Movement; D002478:Cells, Cultured; D003131:Combined Modality Therapy; D042783:Endothelial Cells / Q000473:pathology / Q000502:physiology; D006614:Hindlimb / Q000098:blood supply*; D006801:Humans; D007511:Ischemia / Q000628:therapy*; D008297:Male; D032389:Myocytes, Smooth Muscle / Q000502:physiology; D018919:Neovascularization, Physiologic / Q000187:drug effects; D010455:Peptides / Q000627:therapeutic use*; D016491:Peripheral Vascular Diseases / Q000628:therapy*; D011897:Random Allocation; D051381:Rats; D011917:Rats, Inbred Lew; D013234:Stem Cells / Q000473:pathology / Q000502:physiology; D014471:Umbilical Veins / Q000166:cytology; D014665:Vasodilator Agents / Q000627:therapeutic use*
D043925:Angiogenesis Inducing Agents; D010455:Peptides; D014665:Vasodilator Agents; D053607:Adrenomedullin