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Updated: Mar 22, 2026
Orthotopic Aortic Transplantation in Mice for the Study of Vascular Disease
Published on: November 28, 2012
AKT2 Promotes Bone Marrow Cell-Mediated Aortic Protection in Mice
Sili Zou1, Pingping Ren2, Lin Zhang2
1Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas; Department of Cardiovascular Surgery, Texas Heart Institute, Houston, Texas; Department of Vascular Surgery, Changzheng Hospital, Second Military Medical University, Shanghai, China.
Background:
Insufficient aortic protection and repair may contribute to the development of aortic aneurysms and dissections (AAD). However, mechanisms of aortic protection and repair are poorly understood. We have shown that the multifunctional kinase AKT2 plays an important role in protecting the aortic wall. Here, we examined whether AKT2 protects against AAD by promoting bone marrow cell (BMC)-mediated aortic protection.
Methods:
Irradiated wild-type mice received green fluorescent protein-expressing BMCs from wild-type mice or Akt2(-/-) mice, followed by challenge with angiotensin II (1000 ng/kg/min) infusion for 4 weeks. We compared BMC recruitment, aortic destruction, and AAD development between groups. The direct effects of wild-type and Akt2(-/-) BMCs on smooth muscle cell survival were examined in coculture experiments.
Results:
After angiotensin II infusion, no (0 of 14) wild-type BMC recipients had AAD; in contrast, 64% (9 of 14) of Akt2(-/-) BMC recipients had AAD (p = 0.002) with severe aortic destruction. Compared with aortas from challenged wild-type BMC recipients, aortas from challenged Akt2(-/-) BMC recipients showed significantly less BMC recruitment, NG2 (neuron-glial antigen 2) progenitor activation, and FSP1 (fibroblast-specific protein 1) fibroblast activation. In addition, aortas from challenged Akt2(-/-) BMC recipients showed increased apoptosis and inflammation. In coculture experiments, wild-type but not Akt2(-/-) BMCs prevented smooth muscle cells from undergoing oxidative stress-induced apoptosis.
Conclusions:
After aortic challenge, BMCs are recruited to the aortic wall and provide protection by activating progenitors and fibroblasts and by promoting aortic cell survival. Our findings indicate that AKT2 is involved in these processes and that defects in this pathway may promote progressive degeneration during AAD development.
