Fgf23 expression increases atherosclerotic plaque burden in male ApoE deficient mice.

Introduction: Components of both the innate and adaptive immune system impact on arterial walls in atherosclerosis. Fibroblast growth factor-23 (FGF23) is a phosphate regulating hormone linked to cardiovascular disease (CVD) in patients with and without chronic renal disease. However, it remains controversial whether FGF23 is merely a biomarker or contributes to CVD. Here, we overexpressed Fgf23 in ApoEmice to delineate the role of FGF23 in atherogenesis.

Methods And Results: 10-week old ApoE mice received a hydrodynamic tail vein with a plasmid encoding for Fgf23, and were sacrificed 10 weeks later. FGF23 concentrations increased more than 400-fold in the Fgf23 treated group, remaining high throughout the experiment. Mice in the Fgf23 group developed hypophosphatemia, secondary hyperparathyroidism and a moderate increase in plasma creatinine concentrations. Male ApoE mice exposed to high Fgf23 developed larger atherosclerotic lesions compared to controls, in two different locations of aorta, whereas no differences in plaque burden were seen between female ApoE mice and controls. Serum IL-6 concentrations were increased in the Fgf23 group, associated with a vascular inflammatory response of recruited macrophages and neutrophils, and with a shift of CD4 T effector cells from Th1 to Th17 and migration of lymphocytes to the spleen.

Conclusion: Fgf23 overexpression increases the atherosclerotic burden in male ApoE mice and alters both the innate immune system and T cell subpopulations, generating an inflammatory environment that may promote adverse clinical outcomes associated with FGF23 excess.