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Background: S100A12, also known as EN-RAGE (extracellular newly identified receptor for advanced glycation end products binding protein) is a ligand for RAGE, and has been proposed to contribute to the development of atherosclerosis. In this study, we examined the plasma S100A12 concentration in patients with ESRD and undergoing hemodialysis (HD) and evaluated the relation between S100A12 level and carotid intimal media thickness (IMT) by ultrasound. Methods: We measured plasma S100A12 concentration in 72 HD patients and 42 control subjects. IMT of the carotid artery was measured by high-resolution B-mode ultrasonography in 46 HD patients. Results: The mean plasma S100A12 level was 2.3-fold higher in HD patients than in control subjects (25.0 ± 2.32 vs. 10.7 ± 0.97 ng/ml, p < 0.001). Stepwise multiple regression analysis identified circulating white blood cell count as a positive independent determinant and total cholesterol and serum albumin levels as negative independent determinants of plasma S100A12 concentration. The maximum IMT was positively correlated with plasma S100A12 level. Stepwise multiple regression analysis also identified plasma S100A12 as a significant independent determinant of the maximum IMT. Conclusion: These findings suggest that S100A12 protein is involved in the acceleration of atherosclerosis in HD patients.

The present study demonstrated that HB-EGF processed and released via PC-PLC-PKC signaling is an intermediate molecule for TGF-beta-mediated EGFR transactivation, and subsequent activation of ERK and p38MAPK is involved in FN expression via transcriptional regulation without requiring new protein synthesis.

Sodium restriction is important in the treatment of chronic kidney disease; however, it is sometimes difficult to achieve. Decreased taste sensitivity may be a factor influencing inadequate control of oral salt intake and subsequent high blood pressure. To measure this, the gustatory threshold (recognition and detection) for salty taste was determined in 29 patients with chronic kidney disease using a sodium-impregnated test strip and relevant factors determining taste sensitivity were analyzed. Compared with 11 healthy volunteers, recognition and detection thresholds were increased in the patients with chronic kidney disease. Oral sodium intake correlated positively but serum zinc correlated negatively with the recognition threshold. Patients with diabetic nephropathy had a higher detection threshold than non-diabetic patients. Both recognition and detection thresholds were increased in patients with diuretic administration. After 1 week of sodium restriction, the average recognition threshold decreased significantly. Our study verified that latent taste dysfunction and zinc deficiency are common in patients with chronic kidney disease. Further, the recognition threshold for salty taste improved even after a short period of salt restriction.

SummaryBackground and objectives S100A12 is an endogenous receptor ligand for advanced glycation end products. Cardiovascular disease remains a major cause of morbidity and mortality in patients with chronic kidney disease. In this study, we report cross-sectional data on 550 hemodialysis patients and assess the relationship between plasma S100A12 level and cardiovascular disease.Design, setting, participants, & measurements A cross-sectional study of 550 maintenance hemodialysis patients was conducted. We investigated the past history of cardiovascular disease and quantified the plasma level of S100A12 protein in all participants.Results Plasma S100A12 level was higher in hemodialysis patients with cardiovascular disease (n ϭ 197; 33.8 Ϯ 28.1 ng/ml) than in those without it (n ϭ 353; 20.2 Ϯ 16.1 ng/ml; P Ͻ 0.001). In multivariate logistic regression analysis, the plasma S100A12 level (odds ratio [OR], 1.28; 95% confidence interval [CI], 1.13 to 1.44; P Ͻ 0.001) was identified as an independent factor associated with the prevalence of cardiovascular disease. The other factors associated with the prevalence of cardiovascular diseases were the presence of diabetes mellitus (OR, 2.81; 95% CI, 1.79 to 4.41; P Ͻ 0.001) and high-sensitivity CRP level (OR, 1.02; 95% CI, 1.00 to 1.05; P ϭ 0.046). Furthermore, the plasma S100A12 level (OR, 1.30; 95% CI, 1.09 to 1.54; P ϭ 0.004) was significantly associated with cardiovascular disease even in hemodialysis patients without diabetes mellitus (n ϭ 348). ConclusionsThese results suggest that the plasma S100A12 protein level is strongly associated with the prevalence of cardiovascular disease in hemodialysis patients.

In the development of diabetic nephropathy, angiotensin (Ang) II is thought to exert numerous actions on the glomerulus, and especially on the mesangium. However, the role(s) played by Ang II in the glucose metabolism per se in mesangial cells remains unclear. Ang II, at least via its type 1 receptor (AT1-R)-mediated effect, phosphorylates extracellular signal regulated kinase (ERK) by transactivation of epidermal growth factor receptors (EGF-Rs) via the Ca2+ or protein kinase C (PKC) pathways. Our objective in the present study was to assess the effect of Ang II on glucose transporter 1 (GLUT1) gene expression and to clarify the involvement of EGF-R in Ang II-mediated GLUT1 mRNA expression in glomerular mesangial cells. The results showed that Ang II upregulated GLUT1 mRNA accumulation in a time- and dose-dependent manner (peaking at 12 h; approximately 3.8-fold vs. control), and this upregulation was completely inhibited by the PKC inhibitor calphostin-C. The Ang Il-induced GLUT1 expression was significantly inhibited by the EGF-R inhibitor AG1478 (approximately 80% inhibition), by inactivation of ERK by PD98059, and by pretreatment with heparin and the metalloproteinase (MMP) inhibitor batimastat. On the other hand, phorbol ester markedly upregulated GLUT1 mRNA (approximately 8.6-fold). Batimostat and AG1478 significantly reduced the phorbol ester-induced GLUT1 mRNA expression (approximately 72 and approximately 69% inhibition, respectively). In conclusion, PKC-mediated heparin-binding (HB)-EGF/EGF transactivation followed by ERK activation plays a predominant role in the induction of GLUT1 expression by Ang II.

In most cases of systemic lupus erythematosus (SLE), glomerular lesions are the main renal complication. Although tubulointerstitial lesions are often associated with severe glomerular lesions, predominant or isolated tubulointerstitial injury in the presence of minimal glomerular abnormalities with SLE, so-called predominant tubulointerstitial lupus nephritis, is rare. Only ten cases are reported in the English literature. Herein, we describe the case of a 64-year-old man with SLE who presented with acute renal deterioration attributable to acute tubulointerstitial nephritis. Renal biopsy showed diffuse infiltration of inflammatory mononuclear cells in the interstitium and tubulitis without significant glomerular lesions. Immunofluorescence study revealed positive staining for IgG, C3, and C1q along the renal tubular basement membrane (TBM). Electron microscopy also showed electron-dense deposits in the TBM. Other causes of tubulointerstitial injury, such as drug use and infection, were ruled out. Taking these findings together with the presence of antitubular basement membrane antibody, predominant tubulointerstitial lupus nephritis was diagnosed. Treatment with oral corticosteroids for 6 weeks improved renal function. Even after tapering of the corticosteroid, renal function and serological markers of SLE activity have remained stable in this patient for more than 12 months.

Background/Aims: Glomerular basement membranes (GBM) and tubular basement membranes (TBM) consist of a fine meshwork composed mainly of type IV collagen. Each segment of tubules has specialized physiologic functions, and thus we investigated the ultrastructure of various basement membranes in rat kidneys. Methods: Since purifying basement membranes from different tubule segments is technically challenging, we employed tissue negative staining rather than conventional negative staining to compare the ultrastructures of proximal and distal TBM and GBM in normal rats. We also assessed the distribution of extracellular matrix components including type IV collagen, laminin, heparan sulfate proteoglycan, and fibronectin in the basement membranes by immunohistochemistry. Results: TBM and GBM of normal rats showed a fine meshwork structure consisting of fibrils forming small round to oval pores. Short- and long-pore diameters in proximal tubules were 3.3 ± 0.5 and 3.9 ± 0.6 nm, respectively, and in distal tubules 3.5 ± 0.7 and 4.3 ± 0.8 nm, respectively. For GBM the respective diameters were 2.5 ± 0.5 and 3.0 ± 0.5 nm. Immunohistochemical analysis showed no significant difference in distribution of extracellular matrix components between proximal and distal TBM. However, immunofluorescence scores of α1 chain of type IV collagen, fibronectin, and laminin were higher in the TBM than in the GBM. On the other hand, heparan sulfate proteoglycan was higher in the GBM. Conclusion: Ultrastructural differences in renal basement membranes may be related to differences in physiologic function in each segment.