Advanced glycation end products (AGE) are known to serve as ligands for the scavenger receptors such as SR-A, CD36 and SR-BI. In the current study, we examined whether AGE is recognized by lectin-like oxidized low density lipoprotein receptor-1 (LOX-1). Cellular binding experiments revealed that AGE-bovine serum albumin (AGE-BSA) showed the specific binding to CHO cells overexpressing bovine LOX-1 (BLOX-1), which was effectively suppressed by an anti-BLOX-1 antibody. Cultured bovine aortic endothelial cells also showed the specific binding for AGE-BSA, which was suppressed by 67% by the anti-BLOX-1 antibody. Thus, LOX-1 is identified as a novel endothelial receptor for AGE. ß

To assess a role for oxidative stress in the pathogenesis of amyotrophic lateral sclerosis (ALS), we analyzed the immunohistochemical localization of 8-hydroxy2'-deoxyguanosine (OHdG) as a nucleic acid oxidation product, acrolein-protein adduct and 4-hydroxy-2-nonenal (HNE)-protein adduct as lipid peroxidation products, Nepsiloncarboxymethyl-lysine (CML) as a lipid peroxidation or protein glycoxidation product, pentosidine as a protein glycoxidation product, and imidazolone and pyrraline as nonoxidative protein glycation products in the spinal cord of three familial ALS patients with superoxide dismutase(SOD 1) A4V mutation, six sporadic ALS patients, and six age-matched control individuals. The spinal cord sections of the control cases did not show any distinct immunoreactivities for these examined products. In the familial ALS cases, intense immunoreactivities for pyrraline and CML were confined to the characteristic Lewy body-like hyaline inclusions, and imidazolone immunoreactivity was located in the cytoplasm of the residual motor neurons. No significant immunoreactivities for other examined products were detected in the familial ALS spinal cords. In the sporadic ALS cases, intense immunoreactivities for pentosidine, CML and HNE-protein adduct were seen in the cytoplasm of the degenerated motor neurons, and OHdG immunoreactivity was located in the cell nuclei of the residual neurons and glial cells. The present results indicate that oxidative reactions are involved in the disease processes of sporadic ALS, while there is no evidence for increased oxidative damage except for CML deposition in the familial ALS spinal cords. Furthermore, it is likely that the accumulation of pyrraline and imidazolone supports a nonoxidative mechanism in SOD1-related motor neuron degeneration.

Objective: The purpose of this study was to clarify the role of glycoxidation and lipid peroxidation of low-density lipoprotein (LDL) in e atherogenesis. Methods and results: We examined the formation of N -(carboxymethyl) lysine (CML), a glycoxidation product, and malondialdehyde (MDA), a lipid peroxidation product, in vitro and their co-localization in human atherosclerotic lesions. Immunochemical analysis revealed that CML was formed in a time-dependent manner by human LDL incubated with copper ions and glucose, i.e. an in vitro model of glycoxidation of LDL. When LDL was exposed to copper ions alone, a small amount of CML was formed, however this was significantly less in oxidized LDL than glycoxidative LDL. In contrast, MDA formation was observed in both oxidation and glycoxidation of LDL, but not in glycation of LDL. Hexitol-lysine (HL), an Amadori product, was formed by both glycation and glycoxidation of LDL, but not by oxidation of LDL. Immunohistochemical analysis showed that CML and MDA accumulated mainly in macrophage / foam cells, while pyrraline, a non-oxidative product of glycation, and apolipoprotein B were localized in the extracellular matrix in atherosclerotic lesions. Atheromas were positive for CML and MDA, but negative for pyrraline. Macrophage / foam cells in atherosclerotic lesions exhibited co-localization of macrophage scavenger receptor-A with CML and MDA, but not with pyrraline. Conclusion: Our results suggest that glycoxidation and lipid peroxidation of LDL synergistically promote the development of atherosclerotic lesions through interaction with macrophage scavenger receptor-A.

Previous studies from our laboratory demonstrated that N(epsilon)-(carboxymethyl)lysine (CML), one of the major advanced glycation end products (AGE), was accumulated in human pyramidal neurons in the hippocampus in an age-dependent manner. This suggests a potential link between AGE-accumulation and the aging process in neurons. The purpose of the present study was to examine whether this notion could be extended to other AGE structures, such as imidazolone and pentosidine. This was done using 19 human brains that were not affected by dementia. The immunohistochemical survey on distribution in brain tissues of imidazolone and pentosidine was carried out with monoclonal antibodies specific for imidazolone and pentosidine. A parallel control experiment was carried out with anti-CML antibody. The results showed that pentosidine and imidazolone were localized in neurons in different areas of human brain tissue, especially in neurons of CA4 in the hippocampus. The characteristic distribution of pentosidine and imidazolone is very similar to that of CML. Furthermore, when the accumulation of these AGE structures was compared with the age of individual brains it was found that accumulation of imidazolone, pentosidine and CML in the CA4 region increased with age. These findings taken together support the notion that the accumulation of AGE structures in the CA4 region might be closely related to the aging process in neurons.

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