UMLS:C0011881 - FACTA Search

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Query: UMLS:C0011881 (diabetic nephropathy)
10,836 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypertension and proteinuria are risk factors for renal disease progression. There is clear evidence that pharmacological blockade of the RAS with angiotensin converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) reduces proteinuria and slows down the progression of renal disease in diabetic and non diabetic nephropathies, a beneficial effect not related to blood pressure control. However, not all patients respond similarly to these treatments. Some patients exhibit a significant beneficial response while others do not. The absence of response may be explained by the incomplete blockade of the RAS obtained with ACEI, which are unable to block completely the formation of AII, some generation of AII is produced via other non ACE pathways. In the search of new alternatives that could improve the antiproteinuric and nephroprotective effects of RAS blockers, the association of ACEI and ARB might prove to be useful. ARB produces a complete blockade of the RAS and stimulates the vasodilating and non-proliferative actions of AII via the AT-2 receptor. Furthermore, ACE inhibitors but not ARB; inhibit the metabolism of kinins, which increases the level of bradykinin, a potent vasodilator. Recently, several authors have shown a more marked antiproteinuric effect of the dual blockade of the RAS versus ACEI or ARB alone in spite of a similar effect on blood pressure. A recent study also has demonstrated that this more marked antiproteinuric effect is associated with a less progression of renal disease in primary, non diabetic nephropathies. Furthermore, at least two studies have shown that, treatment with ARB postpones end-stage renal disease and reduces the rate of decline in renal function in patients with type 2 diabetes and nephropathy, but until now, there is not any clear evidence of a superior beneficial effect of dual blockade versus maximal recommended dose of ARB regarding renal progression in type 2 diabetic nephropathy, which is the most frequent cause of end stage renal disease. Long-term clinical trials are needed and encouraged to further establish the significant role of dual blockade in renal protection particularly in diabetic nephropathy.
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PMID:The reno-protective effect of the dual blockade of the renin angiotensin system (RAS). 1585 85

Diabetic nephropathy is the leading cause of chronic renal failure in westernized countries. The polymorphism in angiotensin-converting enzyme (ACE), which leads to higher than normal levels of this enzyme, is a predictor of nephropathy in patients with diabetes. As increasing the levels of ACE by approximately 50% in this polymorphism is only calculated to increase the levels of angiotensin II by < 5%, whereas the levels of bradykinin will decrease by 20%, bradykinin may be nephroprotective. In diabetic mice without bradykinin B2 receptors, the only parameter that is altered compared with the diabetic mouse, is that the nephropathy is worse. Thus, in diabetic mice without a bradykinin receptor (Bdrb2(-/-)Ins2(+/C96Y)), compared with diabetic mice (Bdrb2(+/+)/Ins2(+/C96Y)), there is a greater kidney weight, increased urinary albumin output, and glomeruli mesangial sclerosis. In addition to reducing the levels of angiotensin II, vasopeptidase inhibitors increase the level of bradykinin. A vasopeptidase inhibitor (AVE7688) has been shown to prevent nephropathy developing and to ameliorate it once it has developed in Zucker diabetic rats. The nephroprotective effects (reduced albumin secretion and reduced kidney damage) of AVE7688 in Zucker diabetic rats were partially prevented by the bradykinin B2 receptor antagonist icatibant. These data establish that stimulation of bradykinin B2 receptors is a target in diabetic nephropathy.
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PMID:Bradykinin B2 receptors--a target in diabetic nephropathy. 1593 24

Diabetic nephropathy is the leading cause of chronic renal failure in countries in the western world. Human polymorphism studies have suggested a nephroprotective effect that is mediated by bradykinin B2 receptors. Angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers have an additive nephroprotective effect in patients with diabetes, which may be due to ACE-inhibitor-mediated increases in the levels of bradykinin. There is also evidence from studies conducted in genetically altered mice to suggest that bradykinin is nephroprotective. Finally, evidence from animal models of nephropathy indicates that some of the beneficial effects of ACE inhibitors and vasopeptidase inhibitors are due to the action of bradykinin at B2 receptors. These data establish that stimulation of bradykinin B2 receptors is a target in diabetic nephropathy, and should provide impetus for the development of non-peptide, selective bradykinin B2 agonists.
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PMID:Bradykinin B2 receptors as a target in diabetic nephropathy. 1655 85

Angiotensin converting enzyme (ACE) plays an essential role in two physiological systems, one leading to the production of angiotensin II and the other to the degradation of bradykinin. The wide distribution and multifunctional properties of these peptides suggest that ACE could be involved in various pathophysiological conditions. The discovery that ACE levels are under genetic control ushered in a new era of investigation; most studies focused on an insertion/deletion (I/D) polymorphism in intron 16 of the ACE gene as a marker for a functional polymorphism. Recently, many single nucleotide polymorphisms were detected in the gene and the search for the locations of functional polymorphisms became a topic of extensive investigation. Nevertheless, association studies on the I/D polymorphism and clinical outcomes continued, mostly with conflicting results. This article reviews the current state of knowledge regarding ACE polymorphisms and suggests that a functional polymorphism is most likely located between intron 18 and the 3' UTR. The potential existence of another functional polymorphism in the 5' UTR, however, cannot be excluded. This review also presents an overview of ACE function in different pathophysiological systems, and summarizes previous reports on ACE and clinical outcomes. Although findings on the I/D polymorphism and disorders like diabetic nephropathy and Alzheimer disease can be considered conclusive, reports on most of the cardiovascular phenotypes are still controversial. Genotypic and phenotypic misclassifications, insufficient power in some studies, and the presence of interaction with other genes or environmental factors are possible explanations for the contradictory findings.
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PMID:ACE polymorphisms. 1669 Aug 93

Linkage studies have mapped loci for diabetic nephropathy and associated phenotypes on chromosome 3q. We studied 14 plausible candidate genes in the linkage region because of their potential role in vascular complications. In a large-scale study of patients from Denmark, Finland, and France who have type 1 diabetes, 1,057 case and 1,127 control subjects, as well as 532 trios, were investigated for association with diabetic nephropathy. We analyzed 69 haplotype-tagging single nucleotide polymorphisms and nonsynonymous variants that were identified by sequencing. Polymorphisms in three genes, glucose transporter 2 (SLC2A2), kininogen (KNG1), and adiponectin (ADIPOQ), showed nominal association with diabetic nephropathy in single-point analysis. The T-allele of SLC2A2_16459CT was associated with a decreased risk of diabetic nephropathy (odds ratio 0.79 [95% CI 0.66-0.96], P = 0.016), whereas the T-allele of KNG_7965CT and the A-allele of ADIPOQ_prom2GA were associated with increased risk of nephropathy (1.17 [1.03-1.32], P = 0.016; 1.46 [1.11-1.93], P = 0.006, respectively). Analyses of the transmission disequilibrium test showed similar trends only for ADIPOQ_prom2GA with the overtransmission of the A-allele to patients with diabetic nephropathy (1.52 [0.86-2.66], P = NS) and of the G-allele to patients without diabetic nephropathy (0.50 [0.27-0.92], P = 0.026). The overall significance for this variant (nominal P = 0.011) suggests that ADIPOQ might be involved in the development of diabetic nephropathy.
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PMID:Analysis of 14 candidate genes for diabetic nephropathy on chromosome 3q in European populations: strongest evidence for association with a variant in the promoter region of the adiponectin gene. 1706 57

Diabetic nephropathy (DN) is associated with increased oxidative stress, overexpression and activation of growth factor receptors, including those for transforming growth factor-beta1 (TGF-beta-RII), platelet-derived growth factor (PDGF-R), and insulin-like growth factor (IGF1-R). These pathways are believed to represent pathophysiological determinants of DN. Beyond perfect glycemic control, angiotensin-converting enzyme inhibitors (ACEI) are the most efficient treatment to delay glomerulosclerosis. Since their mechanisms of action remain uncertain, we investigated the effect of ACEI on the glomerular expression of these growth factor pathways in a model of streptozotocin-induced diabetes in rats. The early phase of diabetes was found to be associated with an increase in glomerular expression of IGF1-R, PDGF-R, and TGF-beta-RII and activation of IRS1, Erk 1/2, and Smad 2/3. These changes were significantly reduced by ACEI treatment. Furthermore, ACEI stimulated glutathione peroxidase activity, suggesting a protective role against oxidative stress. ACEI decreased ANG II production but also increased bradykinin bioavailability by reducing its degradation. Thus the involvement of the bradykinin pathway was investigated using coadministration of HOE-140, a highly specific nonpeptidic B2-kinin receptor antagonist. Almost all the previously described effects of ACEI were abolished by HOE-140, as was the increase in glutathione peroxidase activity. Moreover, the well-established ability of ACEI to reduce albuminuria was also prevented by HOE-140. Taken together, these data demonstrate that, in the early phase of diabetes, ACEI reverse glomerular overexpression and activation of some critical growth factor pathways and increase protection against oxidative stress and that these effects involve B2-kinin receptor activation.
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PMID:ACE inhibitor reduces growth factor receptor expression and signaling but also albuminuria through B2-kinin glomerular receptor activation in diabetic rats. 1759 23

Diabetic nephropathy (DN), the leading cause of end-stage renal failure, is clinically manifested by albuminuria and a progressive decline in glomerular filtration rate. The factors and mechanisms that contribute to progression of DN are still undefined. To address the contribution of B(2)-kinin receptors (B2KR) to the development of DN, we studied B2KR knockout mice (B2KR(-/-)) and their wild-type littermates (B2KR(+/+)). Diabetes was induced by daily injections of streptozotocin (50 mg/kg body wt) for 3-5 days. A total of 48 mice divided into 4 groups were used: group 1, wild-type control (B2KR(+/+) C); group 2, wild-type diabetic (B2KR(+/+) D); group 3, B2KR knockout control (B2KR(-/-) C); and group 4, B2KR knockout diabetic (B2KR(-/-) D). Glucose levels and albumin excretion rate (AER) were measured at predetermined intervals. Half of the mice were killed at 3 mo, and the remaining half, at 6 mo. Plasma glucose levels were markedly elevated in both B2KR(+/+) D and B2KR(-/-) D groups of mice compared with their controls. Diabetic B2KR(-/-) mice displayed reduced AER as well as reduced glomerular and tubular injury compared with diabetic B2KR(+/+) mice. The renoprotection conferred by deletion of B2KR was associated with increased renal expression of B(1)-kinin and angiotensin II AT(2) receptors and decreased expression of connective tissue growth factor. At a cellular level, our findings demonstrate that bradykinin downregulates the expression of AT(2) receptors in mesangial cells. These findings provide the first evidence that targeted deletion of B2KR protects against the development of DN.
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PMID:Targeted deletion of B2-kinin receptors protects against the development of diabetic nephropathy. 1759 25

Meprin metalloproteinases have been implicated in the susceptibility to and progression of diabetic nephropathy and inflammatory bowel diseases. Our studies with experimental models of these diseases in mice are congruent with the conclusion that meprins modulate the inflammatory responses and tissue damage. To determine whether the mouse and human enzymes differ, recombinant forms of meprin A from the two species were compared with respect to structure, substrates and inhibitors. Human homo-oligomeric meprin A formed oligomers ranging from 950,000 to 1,500,000 Da vs. 900,000 Da for mouse meprin A. Human and mouse meprin A exhibited similar activity against azocasein, fibronectin, collagen IV, and peptides such as parathyroid hormone, ghrelin, and gastrin-releasing peptide. The human enzyme had lower activity against gelatin, bradykinin, alpha-melanocyte-stimulating hormone and neurotensin, and higher activity against secretin and orcokinin. Human meprin A showed a preference for acidic residues in the P1' position of the substrate, unlike mouse meprin A. Several metalloproteinase inhibitors had IC(50) values in the nanomolar range, but potency ranged from similar values to a difference of several orders of magnitude for meprins from the two species. This work provides valuable data to improve predictability for human systems based on meprin functions in mouse models.
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PMID:Human and mouse homo-oligomeric meprin A metalloendopeptidase: substrate and inhibitor specificities. 1797 9

Diabetic retinopathy and diabetic nephropathy are common microvascular complications of diabetes. The kallikrein-kinin system (KKS) has been implicated in the development of both conditions, and, in particular, bradykinin and its receptors have been shown to exert angiogenic and proinflammatory actions. Several of the key processes that underlie the development of diabetic retinopathy, such as increased vascular permeability, edema, neovascularization, and inflammatory changes, have been associated with the KKS, and recent work has shown that components of the KKS, including plasma kallikrein, factor XIIa, and high-molecular-weight kininogen, are present in the vitreous of people with diabetic retinopathy. The role of the KKS in the development of diabetic nephropathy is controversial, with both adverse and protective effects of bradykinin and its receptors reported. The review examines the role of the KKS in pathways central to the development of diabetic retinopathy and compares this with reported actions of this system in diabetic nephropathy. The possibility of therapeutic intervention targeting bradykinin and its receptors as treatment for diabetic microvascular conditions is considered.
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PMID:The kallikrein-kinin system in diabetic retinopathy: lessons for the kidney. 1827 58

Diabetic nephropathy (DN) can be delayed by the use of angiotensin-converting enzyme inhibitors (ACEi). The mechanisms of ACEi renal protection are not univocal. To investigate the impact of bradykinin B(2) receptor (B2R) activation during ACE inhibition, type II diabetic mice (C57BLKS db/db) received for 20 wk: 1) ACEi (ramipril) alone, 2) ACEi + HOE-140 (a specific B2R antagonist), 3) HOE-140 alone, or 4) no treatment. The development of DN, defined by an increase in albuminuria and glomerulosclerosis, was largely prevented by ACEi treatment (albuminuria: 980 +/- 130 vs. 2,160 +/- 330 mg/g creatinine; mesangial area: 22.5 +/- 0.5 vs. 27.6 +/- 0.3%). The protective effect of ramipril was markedly attenuated by B2R blockade (albuminuria: 2,790 +/- 680 mg/g creatinine; mesangial area: 30.4 +/- 1.1%), whereas HOE-140 alone significantly increased albuminuria. Despite such benefits, glomerular filtration rate remained unchanged, probably because of the combination of the hypotensive effect of diabetes in this model and the renal hemodynamic action of ramipril. Finally, the renal protective effect of ACEi was associated with a marked decrease in glomerular overexpression of insulin-like growth factor-1 (IGF-1) and transforming growth factor-beta pathways, but also in advanced glycation end product receptors and lipid peroxidation assessed by 4-hydroxy-2-nonenal (4-HNE) adducts. Concomitant blockade of B2R partly restored glomerular overexpression of IGF-1 receptor beta and 4-HNE complexes. These results support the critical role of B2R activation in the mediation of ACEi renal protection against DN and provide the rationale to examine the benefit of B2R activation by itself as a new therapeutic approach for DN.
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PMID:Pharmacological blockade of B2-kinin receptor reduces renal protective effect of angiotensin-converting enzyme inhibition in db/db mice model. 1836 57

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