Reduced acute vascular injury and atherosclerosis in hyperlipidemic mice transgenic for lysozyme

Hyperlipidemia promotes oxidant stress, inflammation, and atherogenesis in apolipoprotein E-deficient (ApoE^(-/-)) mice. Mice transgenic for lysozyme (LZ-Tg) are resistant to acute and chronic oxidative stress and have decreased circulating levels of pro-oxidant advanced glycation end-products (AGEs). Herein we report that TIB-186 macrophages transduced with adenovirus-expressing human LZ (AdV-LZ) containing the AGE-binding domain facilitated AGE uptake and degradation and that AdV-LZ-transduced macrophages and peritoneal macrophages from LZ-Tg mice suppressed the AGE-triggered tumor necrosis factor-α response. We assessed atherosclerosis in LZ-Tg mice crossed with ApoE^(-/-) mice (LZ/ApoE^(-/-)) and found increased serum LZ levels and decreased AGE and 8-isoprostanes levels, although hyperlipidemia remained similar to ApoE^(-/-) controls. Atherosclerotic plaques and neointimal lesions at the aortic root and descending aorta were markedly decreased (by 40% and 80%, respectively) in LZ/ApoE ^(-/-) versus ApoE^(-/-) mice, as were inflammatory infiltrates. The arterial lesions following femoral artery injury in LZ/ApoE^(-/-) mice were suppressed (intimal to media ratio decreased by 50%), as were AGE deposits and vascular smooth muscle cell activation, compared to ApoE^(-/-) mice. Despite hyperlipidemia, development of atheroma and occlusive, inflammatory arterial neointimal lesions in response to injury was suppressed in LZ/ApoE^(-/-) mice. This effect may be due to the antioxidant properties of LZ, which is possibly linked to the AGE-binding domain region of the molecule.