Overexpression of receptor for advanced glycation end products induces monocyte chemoattractant protein-1 expression in rat vascular smooth muscle cell line.

AIM: The receptor for advanced glycation end-products (RAGE) has been suggested to play a pivotal role in the development of diabetic vasculopathy and atherosclerosis; however, due to its low expression, the physiological role of RAGE in vascular smooth muscle cells (VSMC) remains unknown. METHODS: Using VSMC lines stably expressing RAGE (RAGE-A10), we studied the molecular mechanism by which S100B, a RAGE ligand, induces proinflammatory gene expression. RESULTS: S100B induced NF-κB activation and the expression of several proinflammatory genes (MCP-1, IL-6, ICAM-1) at mRNA and protein levels in RAGE-A10, among which MCP-1 expression was the most robust. S100B-induced MCP-1 expression was dose-dependently blocked by inhibitors of JNK (SP600125), p38 (SB203580), MEK-1 (U0126) as well as NF-κB (Bay117085). In RAGE-A10, S100B activated JNK, MEK-1 and p38. S100B-induced MCP-1 promoter activity via NF-κB binding sites and nuclear translocation of NF-κB p65 subunit were blocked by SP600125, U0126, and SB203580 in RAGE-A10. CONCLUSION: Our study demonstrates that S100B increased MCP-1 expression via NF-κB and mitogen-activated protein kinase (JNK, ERK1/2, and p38) pathways in RAGE-overexpressed A10 cell lines. Thus, RAGE-A10 could be a useful cell model for studying the molecular mechanism(s) of up-regulated RAGE in the vasculature.

Transcriptome analysis of aldosterone-regulated genes in human vascular endothelial cell lines stably expressing mineralocorticoid receptor.

A series of studies have demonstrated that endothelial cell is one of the target tissues of aldosterone. Here, we have conducted a transcriptome analysis of aldosterone-inducible genes in human endothelial cell lines stably expressing human mineralocorticoid receptor (MR) by retroviral system (MR-EAhy). We found that aldosterone in physiologic concentrations robustly induced MR-dependent transcriptional response in MR-EAhy. By DNA microarray analysis, we validated 12 aldosterone-up-regulated genes among which at least seven were concomitantly associated with increased protein expression. We also found five aldosterone-down-regulated genes. Among 11 aldosterone-up-regulated genes tested, mRNA expressions of three (ESM1, SNF1LK, ANGPTL4) were significantly up-regulated in aortic tissue from aldosterone-induced hypertensive rats compared to those from control rats, suggesting their potential pathophysiologic significance in vivo. In conclusion, using MR stably expressed human endothelial cell lines, we identified a variety of aldosterone-inducible genes, suggesting their possible roles in the development and/or the protection for aldosterone-induced vascular injury.

Vasculoprotective effect of cilostazol in aldosterone-induced hypertensive rats.

Cilostazol (CILO), a selective inhibitor of phosphodiesterase 3 with potent antithrombotic property, has been shown to have a vasculoprotective effect in atherosclerosis animal models due to its potential anti-inflammatory and antioxidant actions. This study was undertaken to investigate whether CILO has in fact any vasculoprotective effects in aldosterone-induced hypertensive rats (Aldo-rats), and whether CILO affects Aldo-induced oxidative stress, nitric oxide (NO) production and pro-inflammatory gene expression. Treatment with CILO markedly ameliorated perivascular inflammatory changes in the coronary arterioles of Aldo-rats without affecting the systolic blood pressure and left ventricular weight. Treatment with CILO also prevented the increase in plasma levels of thiobarbituric acid-reactive substances, an oxidative stress marker, as well as decreased urinary NOx excretion in Aldo-rats. Furthermore, CILO almost completely inhibited a set of upregulated proinflammatory genes (ICAM-1, MCP-1, PDGF-A, osteopontin, MMP-2 and ACE), as well as NAD(P)H oxidase components (p22phox, gp91phox, p47phox) and Aldo-inducible genes (SGK-1 and NHE-1) in the aortic tissues from Aldo-rats. Taken together, this study showed for the first time that CILO prevented Aldo-induced vascular inflammation and injury without affecting the blood pressure, suggesting its vasculoprotective effect on Aldo-induced vascular injury independent of blood pressure.

Acromegaly associated with multiple tumors.

A 56-year-old man was admitted to our hospital for the surgical removal of renal cell carcinoma (RCC). He was diagnosed with acromegaly due to his characteristic clinical features, endocrine data, and the presence of pituitary tumor. He was found to have colon cancer and follicular thyroid tumor. Pathological examination of the pituitary tumor after transsphenoidal surgery was compatible with growth hormone (GH)-secreting pituitary adenoma. We also detected the transcripts and/or immunoreactivity of GH/insulin-like growth factor I components in the tumor specimen. This is a rare case of acromegaly associated with multiple tumors, including RCC, colon cancer and thyroid tumor.

Late-night salivary cortisol as a screening test for the diagnosis of Cushing's syndrome in Japan.

Measurement of late-night and/or midnight salivary cortisol currently used in US and European countries is a simple and convenient screening test for the initial diagnosis of Cushing's syndrome (CS). Unfortunately, this test has not been widely used in Japan. The purpose of this study was to evaluate the usefulness of the measurement of late-night salivary cortisol as a screening test for the diagnosis of CS in Japan. We studied 27 patients with various causes of CS, consisting of ACTH-dependent Cushing's disease [5] and ectopic ACTH syndrome [4] and ACTH-independent adrenal CS [11] and subclinical CS [7]. Eleven patients with type 2 diabetes and obesity and 16 normal subjects served as control group. Saliva samples were collected at late-night (23:00) in a commercially available device and assayed for cortisol by radioimmunoassay. There were highly significant correlations (P<0.0001) between late-night serum and salivary cortisol levels in normal subjects (r = 0.861) and in patients with CS (r = 0.788). Late-night salivary cortisol levels in CS patients (0.975 +/- 1.56 microg/dl) were significantly higher than those in normal subjects (0.124 +/- 0.031 microg/dl) and in obese diabetic patients (0.146 +/- 0.043 microg/dl), respectively. Twenty-five out of 27 CS patients had late-night salivary cortisol concentrations greater than 0.21 microg/dl, whereas those in control group were less than 0.2 microg/dl. Receiver operating characteristic curve (ROC) analysis showed that the cut-off point of 0.21 microg/dl provides a sensitivity of 93% and a specificity of 100%. Therefore, it is concluded that the measurement of late-night salivary cortisol is an easy and reliable noninvasive screening test for the initial diagnosis of CS, especially useful for large high-risk populations, such as diabetes and obesity.