Vascular complications are an important cause of morbidity and mortality in patients with diabetes. The extent of vascular complications has been linked statistically to enhanced adherence ofdiabetic erythrocytes to endothelial cells (ECs) and to the accumulation of a class of glycated proteins termed advanced glycation end products (AGEs). We Nonenzymatic glycation ofproteins, such as hemoglobin, has been shown to provide a useful index for management of patients with diabetes (1). The ultimate result of the nonenzymatic glycation and oxidation of proteins is formation of advanced glycation end products (AGEs), whose presence in plasma and tissues has been linked to the development of complications in diabetics (2-5). The cellular interactions of AGEs are mediated by receptors/cell surface binding proteins identified on endothelial cells (ECs) and mononuclear phagocytes (MPs), engagement of which leads to perturbation of cellular functions (3,(6)(7)(8). Our studies have characterized an integral membrane protein, receptor for AGE (RAGE), a newly discovered member of the immunoglobulin superfamily, which has a central role in mediating the interactions of AGEs with cellular surfaces (7-9).We previously showed that erythrocytes from diabetic patients exhibited enhanced binding to cultured endothelium (10). We hypothesized that, dependent on the duration of exposure of erythrocytes to plasma hyperglycemia, AGE modification oferythrocyte surface membrane proteins could occur, allowing them to bind and thereby to modulate properties of RAGE-expressing vessel wall cells. Our studies demonstrate that the molecular basis of the increased adherence of diabetic erythrocytes results largely from AGEs on the erythrocyte surface interacting with EC RAGE. This results in the induction of oxidant stress in the endothelium, potentially modulating expression of a spectrum ofgenes that could contribute to the pathogenesis of vascular complications.MATERIALS AND METHODS Subjects. The group of patients (n = 18 each for the normal and diabetic subjects) was comparable in age, duration of diabetes, fasting blood glucose, and hemoglobin Alc levels.Erythrocytes from two patients homozygous for sickle cell disease were also studied.Erythrocyte Adhesion Assay. Cultured human umbilical vein ECs were prepared and assayed as described (10-12).The specific activity of 51Cr-labeled erythrocytes for normal and diabetic erythrocytes was 3750 ± 260 and 3820 ± 253 cpm per mg of hemoglobin, respectively. The adhesion ratio (AR) was calculated as follows: AR = (cpm of diabetic erythrocytes)/(cpm of normal erythrocytes). An AR value of 1 represents the adhesion observed with normal erythrocytes. Where indicated, either erythrocytes or ECs were preincubated with soluble RAGE (sRAGE) or antibodies and EC nuclear extracts were prepared (13).Preparation of AGE-Modified Proteins, AGE Binding Proteins, and Antisera. AGE albumin was prepared and characterized as described (3,7,8). AGE binding proteins were purified from bovine lung (7) and cons...

Paradoxical reactions are frequent in the course of extrapulmonary TB treatment in HIV-negative patients but their outcome is excellent, except in some cases with central nervous system involvement.

Extracellular nucleotides, particularly ATP, are involved in the modulation of arterial vasomotricity via P2 purinoceptors present on smooth muscle and endothelial cells. These nucleotides could also be implicated in the smooth muscle cell hyperplasia observed in intimal lesions. In this study, we tried to define the potential role of the P2Y2 (P2u) purinoceptor by studying its expression in normal and balloon-injured rat aortas. The cloning of a rat P2Y2 cDNA from a rat smooth muscle cell cDNA library made it possible to study P2Y2 expression both by Northern blot and in situ hybridization. Northern blot experiments indicated that P2Y2 mRNA was present in rat medial aortic smooth muscle and in cultured rat aortic smooth muscle cells. In situ hybridization indicated that P2Y2 mRNA was present in endothelial cells of the intima and in some smooth muscle cells scattered throughout the media of adult rat aortas, while almost all medial smooth muscle cells of rat embryo aorta expressed this receptor. In contrast with adult aortic media, the majority of neointimal smooth muscle cells found in aortic intimal lesions either 8 or 20 days after balloon injury were positive for P2Y2 mRNA. Moreover, a subpopulation of neointimal cells localized at the luminal surface could be identified by a higher P2Y2 expression than the underlying neointimal smooth muscle cells. These data showing a strong expression of the P2Y2 purinoceptor in the neointima of injured arteries suggest that extracellular nucleotides may be involved, via this receptor, in the intimal hyperplasia and/or chronic constriction observed at the lesion site, and consequently in the restenotic process.