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ABSTRACT: Aim: Angiotensin-converting enzyme 2 (ACE2) is a type I membrane protein that antagonizes the action of angiotensin II. Because of the need for invasive kidney biopsy, little is known about the role of renal ACE2 in human kidney diseases. The authors studied if urinary ACE2 could provide a novel clue to renal ACE2 in chronic kidney disease (CKD). Methods: Subjects were 190 patients with CKD including 38 patients with diabetic nephropathy and 36 healthy subjects. Parameters were urinary ACE2 by enzyme-linked immunosorbent assay, blood pressure, casual plasma glucose, proteinuria, microalbuminuria, serum creatinine and estimated glomerular filtration rate. Urine and serum samples were also subjected to western blotting of ACE2. Results: Western blotting confirmed increased urinary ACE2 levels in patients with CKD. Urinary ACE2 was significantly higher in patients with CKD than healthy subjects (median 9.64 (interquartile range, 4.41-16.89) vs 1.50 (0.40-2.33) mg/g·creatinine, P < 0.001) and in patients with diabetic nephropathy than patients without diabetic nephropathy (median 13.16 (interquartile range 6.81-18.70) vs 8.90 (4.19-16.67) mg/g·creatinine, P < 0.05). No significant difference in urinary ACE2 was observed by the use of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker. Conclusion: Urinary ACE2 could be used as a non-invasive marker to understand the role of renal ACE2 in CKD. [ABSTRACT FROM AUTHOR]

Background: Angiotensin-converting enzyme (ACE)2 forms angiotensin-1-7 which may protect kidney in a counterregulatory manner to angiotensin II. Recent studies revealed increased ACE and decreased ACE2 expression in kidneys of patients with diabetic nephropathy. However, these changes may not be specific for diabetic nephropathy. We studied ACE and ACE2 expression in patients with IgA nephropathy. Methods: Renal ACE and ACE2 expression was assessed by immunohistochemistry and in situ hybridization in 30 patients with IgA nephropathy and 21 healthy controls. Correlation between ACE and ACE2 expression and levels of various biochemical parameters was also assessed. Gene expression was also assessed in minimal change nephrotic syndrome (MCNS) and membranous nephropathy (MN) as disease controls. Results: Reduced ACE2 expression (p < 0.01) and increased ACE expression in glomeruli (p < 0.001), and reduced ACE2 expression in tubulointerstitium (p < 0.001) were observed in patients with IgA nephropathy compared to healthy controls, although the changes in ACE2 mRNA were not statistically significant. Reduced renal ACE2 expression was also found in MN but not in MCNS. Correlation between renal ACE and ACE2 expression and proteinuria was not observed in IgA nephropathy. Conclusion: IgA nephropathy is associated with increased ACE and decreased ACE2 expression in kidneys, as in diabetic nephropathy. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Transforming growth factor β1 (TGF-β1) and vascular endothelial growth factor (VEGF) are involved in peritoneal deterioration in continuous ambulatory peritoneal dialysis. The present study was designed to determine whether new peritoneal dialysis solutions (PDS), pyridoxamine (advanced glycation end products (AGE) inhibitor) or AT1 receptor blocker (ARB), affect the expression of VEGF and TGF-β1 in rat peritoneal mesothelial cells (RPMC). Methods: RPMC were stimulated by phosphate-buffered saline (PBS) as control, Dianeal 1.5% (D 1.5%), Dianeal 2.5% (D 2.5%), Dianeal 4.25% (D 4.25%), Dianeal N 1.5% (N 1.5%), Dianeal N 2.5% (N 2.5%) or Extraneal (Ex). In co-incubation experiments, RPMC were stimulated with N 2.5% including pyridoxamine or olmesartan (ARB). VEGF and TGF-β1 protein and mRNA expression in RPMC were analyzed by ELISA and RT-PCR. Results: Glucose-containing PDS, even N 2.5% diluted twofold with M199 (which contains 1.25% glucose), increased VEGF and TGF-β1 expression in RPMC (p < 0.05). Ex did not inhibit VEGF expression and did not inhibit TGF- β1 expression after 24 h in RPMC. Pyridoxamine and ARB significantly reduced N 2.5%-induced VEGF and TGF-β1 protein and mRNA expression in RPMC (p < 0.01). Conclusions: Neither new pH-neutral, lactate-buffered, low-GDP, two-chamber bag PDS, nor 7.5% icodextrin PDS alone satisfactorily inhibited VEGF and TGF-β1 overproduction in RPMC, but ARB or pyridoxamine effectively inhibited glucose-containing PDS (N 2.5%)-induced overproduction. Copyright © 2009 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Inactivation of the DNA mismatch repair gene hMLH1 predisposes one to colorectal cancer. We have identified a C to G nucleotide substitution at position –107 relative to the hMLH1 gene translation initiation site in three of 163 colorectal cancer patients with an allele frequency of 0.0092 (3/326). One of the three −107G alleles occurred in one patient out of five with reduced hMLH1 expression in the tumor tissue. The −107G was not found in 63 healthy individuals. This substitution reduced transcriptional activity by 51% compared with −107C (P < 0.01) and impeded the promoter-binding capacity of nuclear proteins. Although the small number of identified −107G alleles is insufficient to evaluate the contribution to the carcinogenesis and clinicopathological properties of the tumors, the effects of −107G on hMLH1 gene transcription and nuclear protein binding to the promoter sequence implicate the site, including −107C, as a crucial element interacting with the activator that maintains hMLH1 gene expression. [ABSTRACT FROM AUTHOR]