Deficiency or pharmacological blockade of the angiotensin II type 1a receptor significantly impaired ischemia-induced angiogenesis and blood flow recovery in a mouse model of hindlimb ischemia.
Does the ATII-AT1 receptor pathway promote ischemia-induced angiogenesis in a mouse model of hindlimb ischemia?
The ATII-AT1 receptor pathway promotes early ischemia-induced angiogenesis by supporting inflammatory cell infiltration and angiogenic cytokine expression.
p-value: p=<0.05
The role of the renin-angiotensin system (RAS) in angiogenesis is little known. Here, we show that the angiotensin II (ATII) type 1 (AT1) receptor plays an important role in ischemia-induced angiogenesis. Well-developed collateral vessels and angiogenesis were observed in wild-type (WT) mice in response to hindlimb ischemia, whereas these responses were reduced in ATII type 1a receptor knockout (AT1a(-/-)) mice. Ischemia-induced angiogenesis was also impaired in WT mice treated with the AT1 receptor blocker TCV-116. These effects were not due to reduced systemic blood pressure (SBP), because hydralazine treatment preserved angiogenesis in WT mice although it reduced SBP to a level similar to that of AT1a(-/-) mice. Infiltration of inflammatory mononuclear cells (MNCs), including macrophages and T lymphocytes, was suppressed in the ischemic tissues of AT1a(-/-) mice compared with WT mice. Double immunofluorescence staining revealed that infiltrated macrophages and T lymphocytes expressed VEGF, and the expression of VEGF and monocyte chemoattractant protein-1 was also decreased in AT1a(-/-). Finally, the impaired angiogenesis in AT1a(-/-) mice was rescued by intramuscular transplantation of MNCs obtained from WT mice, further indicating the importance of MNC infiltration in ischemia-induced angiogenesis. Thus, the ATII--AT1 receptor pathway promotes early angiogenesis by supporting inflammatory cell infiltration and angiogenic cytokine expression.
Sasaki et al. (Fri,) conducted a other in Ischemia-induced angiogenesis (Hindlimb ischemia). AT1a receptor deficiency or TCV-116 (AT1 receptor blocker) vs. Wild-type mice / no treatment was evaluated on Ischemic/normal hindlimb blood flow ratio (LDBF ratio) (p=<0.05). Deficiency or pharmacological blockade of the angiotensin II type 1a receptor significantly impaired ischemia-induced angiogenesis and blood flow recovery in a mouse model of hindlimb ischemia.