The receptor for advanced glycation end products (RAGE)

SummaryFactor XIII when activated by thrombin, crosslinks fibrin, however its role in thrombotic disorders is unknown. A common point mutation (G T) in exon 2 of the A-subunit gene which codes for an amino acid change three amino acids from the thrombin activation site (Factor XIIIVal34Leu) is a candidate for a role in the pathogenesis of acute myocardial infarction. Factor XIII genotype frequencies were determined in a case-control study of 398 caucasian patients and 196 healthy controls. Patients had undergone angiography for investigation of coronary artery disease and were evaluated for a history of myocardial infarction. The prevalence of the mutation was lower in patients with myocardial infarction than without (32% vs. 50%), p = 0.0009 and than in controls (32% vs. 48%), p = 0.005. Patients possessing the mutation with a history of myocardial infarction had higher PAI-1 concentrations (mean, 27.9 vs. 16.7 ng/ml, p = 0.004) and the PAI-1 4G/4G genotype was commoner (43% vs. 26%, p = 0.03). There was no difference in PAI-1 4G/4G genotype (33% vs. 32%) and PAI-1 levels (mean, 21.0 vs. 20.9 ng/ml) in patients possessing wild type with MI compared to those without MI. These results indicate that the G T mutation coding for factor XIIIVal34Leu is protective against myocardial infarction and suggest a mechanism whereby elevated levels of PAI-1 may contribute to vascular risk.

Interactions between advanced glycation end products (AGEs) and the receptor for AGE (RAGE) are implicated in the vascular complications in diabetes. We have identified eight novel polymorphisms, of which the ؊1420 (GGT)n, ؊1393 G/T, ؊1390 G/T, and ؊1202 G/A were in the overlapping PBX2 3 untranslated region (UTR), and the ؊429 T/C (66.5% TT, 33.5% TC/CC), ؊407 to -345 deletion (99% I, 1% I/D, 0% D), ؊374 T/A (66.4% TT, 33.6% TA/AA), and ؉20 T/A were in the RAGE promoter. To evaluate the effects on transcriptional activity, we measured chloramphenicol acetyl transferase (CAT) reporter gene expression, driven by variants of the -738 to ؉49 RAGE gene fragment containing the four polymorphisms identified close to the transcriptional start site. The -429 C, ؊374 A, and 63-bp deletion alleles resulted in a mean increase of CAT expression of twofold (P < 0.0001), threefold (P < 0.001), and fourfold (P < 0.05), respectively, with the -374 T and A alleles yielding highly differential binding of nuclear protein extract from both monocyte-and hepatocyte-derived cell lines. The prevalence of the functional polymorphisms were investigated in subjects with type 2 diabetes (106 with and 109 without retinopathy), with the -429 C allele showing an increase in the retinopathy group (P < 0.05). These data suggest that the polymorphisms involved in differences in RAGE gene regulation may influence the pathogenesis of diabetic vascular complications. Diabetes 50:1505-1511, 2001

SummaryTo investigate the interaction of metabolic and genetic factors in relation to PAI-1, genotype was determined at a 4G/5G polymorphism in the PAI-1 gene promoter and at a Hind III RFLP of the PAI-1 gene in 189 Caucasian NIDDM patients. PAI-1 levels were equivalent in each genotype group and PAI-1 activity correlated with fasting insulin (r = 0.45), triglyceride (r = 0.39) body mass index (r = 0.44), cholesterol (r = 0.17) and glucose (r = 0.15). The regression slope (B) of PAI-1 activity on triglycerides was steeper in the 4G/4G group than the other two groups: 4G/4G B = 0.91, r = 0.62; 4G/5G B = 0.36, r = 0.27; 5G/5G B = 0.31, r = 0.29 (difference between slopes p = 0.02) and the association between PAI-1 activity and glucose remained only in the 4G/4G group (r = 0.35). These results confirm the association of PAI-1 levels with the features of insulin resistance and indicate that the association between PAI-1 levels and both triglyceride and glucose is influenced by genotype in the region of the PAI-1 gene promoter.