Although atherosclerotic cardiovascular disease (CVD) is 10-20-fold higher in patients with chronic kidney damage (CKD) than in the general population, our understanding of the underlying mechanisms remains very limited. Notably, CKD is an angiotensin II (AII)-responsive state where targeting AII actions constitutes the cornerstone of medical therapy for a whole range of progressive renal injuries. Atherosclerotic CVD has also been found to be AII responsive in epidemiological studies and experimental models. The proposed studies will evaluate the pathophysiologic and therapeutic implications of interactions between renal dysfunction and AII in promoting atherosclerosis, testing the hypothesis that the macrophage AII type 1 receptor (AT1R) channels proatherogenic mechanisms in this setting. We will use atherosclerosis-prone mice and induce early or moderate CKD. We will use mice deficient in AT1R as bone marrow donors to create chimeric mice with AT1R-deficient infiltrating cells, but intact AT1R on resident vascular cells. We can then evaluate mechanisms of AII effects on macrophages, vascular cells and matrix interactions in the setting of CKD. Our central hypothesis will be tested by the following Specific Aims: I. Define the contribution and mechanisms by which the macrophage AT1R modulates cellular processes involved in CKD-induced acceleration of atherosclerosis. We hypothesize that macrophage AT1R promotes CKD-induced atherogenesis by increasing macrophage infiltration, inflammation, foam cell formation and proteolysis of extracellular matrix. II. Determine the role of modulators of the proatherogenic effects of macrophage AT1R in CKD-induced acceleration of atherosclerosis. We hypothesize that macrophage AT1R activates not only proatherogenic processes but also counterbalancing factors, including macrophage PPAR, which moderate the net vasculopathy.
These studies will further our understanding of the leading cause of death and illness in patients with kidney disease, namely, atherosclerosis. The magnitude of the problem, especially in early kidney damage, has only recently been appreciated and is currently understudied. The proposed experiments will examine how the macrophage, a key inflammatory blood cell, makes the atherosclerosis worse in this setting and may give ideas for better treatment.
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