Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0033687 (proteinuria)
 24,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Endotoxin E. Coli lipopolysaccharide (LPS)-treatment in conscious, restrained rats increased plasma and urinary prostaglandin (PG) and nitric oxide (NO) production. Inducible cyclo-oxygenase (COX-2) and nitric oxide synthase (iNOS) expression accounted for the LPS-induced PG and NO release since the glucocorticoid, dexamethasone inhibited both effects. Thus, LPS (4 mg kg-1) increased the plasma levels of nitrite/nitrate from 14 +/- 1 to 84 +/- 7 microM within 3 h and this rise was inhibited to 35 +/- 1 microM by dexamethasone. Levels of 6-keto PGF1 alpha in the plasma were below the detection limit of the assay (< 0.2 ng ml-1). However, 3 h after the injection of LPS these levels rose to 2.6 +/- 0.2 ng ml-1 and to 0.7 +/- 0.01 ng ml-1 after LPS in rats that received dexamethasone. 2. The induced enzymes were inhibited in vivo with selective COX and NOS inhibitors. Furthermore, NOS inhibitors, that did not affect COX activity in vitro markedly suppressed PG production in the LPS-treated animals. For instance, the LPS-induced increased in plasma nitrite/nitrate and 6-keto PGF1 alpha at 3 h was decreased to 18 +/- 2 microM and 0.5 +/- 0.02 ng ml-1, 23 +/- 1 microM and 0.7 +/- 0.01 ng ml-1, 29 +/- 2 microM and 1 +/- 0.01 ng ml-1 in rats treated with LPS in the presence of the NOS inhibitors NG-monomethyl-L-arginine, NG-nitro arginine methyl ester and aminoguanidine, respectively. 3. The intravenous infusion of the NO donors sodium nitroprusside (SNP) or glyceryl trinitrate (GTN)increased prostaglandin production in normal animals (for instance urinary PGE2 excretion was increased from 96 +/- 10 to 576 +/- 12 pg min-1 and 400 +/- 24 pg min-1 in the presence of GTN or SNP respectively).4. Proteinuria was measured in order to evaluate the roles of NO and PG in renal damage associated with the in vivo injection of LPS. Interestingly, dexamethasone and the NOS inhibitors attenuated proteinuria in the LPS-treated rats. The COX inhibitors had no effect. It therefore appears that NO and not PG contributes to the LPS-induced renal damage; these findings support the potential use of NOS inhibitors in the treatment of renal inflammation.5. This study demonstrates the regulatory contribution of NO on the in vivo production of prostanoids and suggests that in inflammatory diseases that are driven by both NO and the prostaglandins, NOS inhibitors may act to reduce inflammation by the dual inhibition of cytotoxic NO and pro-inflammatory PG.
 ...
PMID:Regulation of prostaglandin production by nitric oxide; an in vivo analysis. 754 31

The kidney vasculature is under tonic control by nitric oxide (NO) and in cortex, NO controls RA and Kf. Systemic NO inhibition leads to systemic hypertension, increases in RE, mediated by Ang II and ET, and direct effects on RA and Kf. The relationship between NO and other vasoconstrictor systems is variable. In the conscious relaxed animal, vasoconstrictor activity is low, yet acute NO inhibition leads to pressor and renal vasoconstrictor responses. At physiologic levels, ET unexpectedly is a renal vasodilator, possibly via NO generation at RA. When vasoconstrictor activity is high, NO is very important in maintenance of renal perfusion. Chronic L-NAME produces dose dependent systemic and glomerular capillary hypertension and eventual proteinuria and glomerular damage. NO deficiency is key in this process, although the hypertension becomes refractory to L-arginine administration and dependent on Ang II and the SNS, by mechanisms not yet defined. In contrast, the renal vasculature remains fully responsive to L-arginine, suggesting that pressor and renal vascular responses to chronic NO inhibition are separately regulated. NO generated from iNOS does not normally control BP or renal hemodynamics. The relative contributions of NO from bNOS and eNOS, and importance of NOS in different locations in the kidney, remain to be determined.
 ...
PMID:Importance of nitric oxide in the control of renal hemodynamics. 874 86

Nitric oxide (NO), an L-arginine derivative, is implicated in neuronal transmission, immune response and vasodilation, and acts as a modulator of platelet function. Recent studies in the experimental model of renal mass reduction (RMR) in rats have generated the hypothesis that abnormalities in the NO synthetic pathway could play a key role in mediating the complex hemodynamic and hemostatic disorders associated with the progression of renal disease. Thus, renal NO generation is lower than normal in rats with RMR 7 days after surgery and progressively worsens with time in close correlation with signs of renal injury. This abnormality is due to a major defect in inducible NO synthase (iNOS) content in the kidney. In the same model, administration of either the NO precursor, L-arginine, or a NO-releasing compound reduces proteinuria, slows renal disease progression, and prolongs survival. In contrast, in the systemic circulation of uremic rats, NO is formed in excessive amounts, possibly caused by higher release from systemic vessels due to the augmented expression of both iNOS and endothelial NOS. Up-regulation of systemic NO synthesis might be a defense mechanism against uremic hypertension. On the other hand, a greater availability of NO to circulating cells may sustain the bleeding tendency, a well-known complication of uremia.
 ...
PMID:Nitric oxide synthesis and L-arginine in uremia. 938 6

Nitric oxide (NO) is an endogenous vasodilator synthesized in the endothelium by constitutive NO synthase (cNOS). We have shown that upregulation of cNOS activity in hypertension may contribute to forestalling left ventricular and aortic hypertrophy (Hypertension. 29: 235, 1997). NO has been shown to inhibit growth-related responses affecting vascular smooth muscle, and mesangial cells, as well as reduce production of extracellular matrix in response to injury. Here, we investigated the relationship between renal cNOS activity (conversion of [14C] L-arginine to [14C] L-citrulline) and glomerular (GIS) and tubulointerstitial (TIS) injury scores and urinary protein excretion, indices of renal injury, in age and blood pressure matched spontaneously hypertensive rats (SHR, SBP 220+/-9 mm Hg) fed 0.5% NaCl diet and Dahl salt-sensitive (DS) rats fed 4% NaCl diet (DS-4%, SBP 228+/-8 mm Hg) as well as their normotensive counterparts Wistar Kyoto rats fed 0.5% NaCl diet (WKY, 137+/-3 mm Hg) and DS rats fed 0.5% NaCl diet (DS-0.5%, SBP 135+/-4 mm Hg). In SHR, renal medullary cNOS activity was 89% higher than in WKY (8.91+/-0.98 vs 4.71+/-0.37 nmol/min/g protein, P<0.05) whereas, in hypertensive DS-4% rats cNOS activity was 43% lower than in DS-0.5% rats (1.98+/-0.16 vs 3.48+/-0.29 nmol/min/g protein, P<0.05). Renal cortical cNOS was lower than in medulla but similar in all groups; inducible NOS activity was not detected. Despite hypertension of similar severity and duration, hypertensive DS-4% developed 9 fold more GIS (190+/-42 vs 21+/-11), 20 fold more TIS (4.0+/-0.7 vs 0.2+/-0.3), and 5 fold more proteinuria (54+/-11 vs 8.5+/-3.0 mg/day), all P<0.05. The current studies, in conjunction with our recent studies in heart and aorta, strongly suggest that in hypertension, increased cNOS activity may provide a protective homeostatic role in all the end-organs that are targets of hypertensive injury.
 ...
PMID:Nitric oxide synthase activity and renal injury in genetic hypertension. 945 14

During gestation endothelium induces decreases in vascular responses to vasopressor agents but endothelium disease is followed by hypertension and enhanced vascular reactivity during preeclampsia. In a rat model of preeclampsia induced by NO synthase inhibition we study here isolated aortic contractions. From day 13 of gestation 2 groups of Wistar female rats were fed control (C) or nitro-arginine enriched diets (0.063%, i.e. 30 mg/kg/d) (treated) (T). On gestational day 20 systolic blood pressure (SBP, mmHg) is measured by tail cuff method and isolated thoracic ring aorta contractions are studied after depolarisation (KCl 60 mM) or norepinephrine (cumulative concentrations 10-9 M-10-5 M). After chronic NOS inhibition, hypertension develops: SBP is 154 +/- 2.17 in T and 116 +/- 3.75 in C, p < 0.01 and significant proteinuria (mg/d) appears: T, 63.4 +/- 21.6 versus C 3.08 +/- 0.48, p < 0.01. NO synthase inhibition in treated rats impairs the depressed contractile response obtained in the presence of endothelium in control rats but addition of L-arginine suppresses the effect of nitroarginine. Taking in account our results and those described in literature it appears that L-arginine treatment could ameliorate some pathologic pregnancies.
 ...
PMID:[Nitric oxide and isolated aortic contraction in a pregnant hypertension model by the inhibition of nitric oxide synthase in pregnant Wistar rats]. 1079 54

Chronic nitric oxide (NO) synthase (NOS) inhibition results in renal injury. Hypertension is an important risk factor for renal injury. We studied the influence of preexistent hypertension on the sensitivity for renal injury induced by chronic NOS inhibition in rats. Spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats were treated with 3, 10, 30 and 100 mg/l Nomega-nitro-L-arginine (L-NNA) until death. Systolic blood pressure and proteinuria were measured regularly and compared with time-control measurements in untreated SHR and WKY. In WKY, 3 and 10 mg/l L-NNA did not affect systolic blood pressure, while 30 and 100 mg/l L-NNA resulted in an increase in systolic blood pressure after 12 and 4 weeks, respectively. In contrast in SHR, every dose of L-NNA resulted in an increase in systolic blood pressure after 2 weeks. In WKY, 3 and 10 mg/l L-NNA did not affect proteinuria or survival, while 30 and 100 mg/l L-NNA resulted in an increase in proteinuria after 30 and 9 weeks, and a median survival of 36 and 12 weeks, respectively. In SHR, 3, 10, 30 and 100 mg/l L-NNA resulted in an increase in proteinuria after 30, 12, 3 and 3 weeks, and a median survival of 41, 20, 5 and 3 weeks, respectively. Thus, at every dose of the inhibitor, chronic NOS inhibition resulted in far earlier increases in systolic blood pressure and proteinuria and a marked increase in mortality in SHR as compared to WKY. Indeed, a very low dosage of L-NNA that caused no harm in WKY was followed by marked increases in proteinuria and blood pressure and decreased survival in SHR. Hypertension strongly increases the vulnerability to cardiovascular risk factors that compromise the NO-system.
 ...
PMID:Predisposition of spontaneously hypertensive rats to develop renal injury during nitric oxide synthase inhibition. 1113 73

Nitric oxide (NO) regulates inflammatory responses partly by cell-specific inhibition of the transcription factor nuclear factor kappaB (NF-kappaB). This study investigated the effect of continuous oral administration of an NO donor (molsidomine [Mol]), NO precursor (L-arginine [L-arg]), or selective inhibitors of inducible NO synthase (iNOS; aminoguanidine [AG], L-N(6)-(1-iminoethyl)lysine [L-NIL]) on the progression of tubulointerstitial inflammation and NF-kappaB activation in a non-immune model of chronic glomerular disease (Adriamycin nephropathy [AN]), from day 8 until day 30 after disease induction. On day 30, rats with AN had heavy proteinuria, reduced creatinine clearance, and tubulointerstitial disease. Treatment with both AG and L-NIL exacerbated the progression of AN as evidenced by (1) increased renal cortical malondialdehyde; (2) reduced creatinine clearance; and (3) increased tubular atrophy, interstitial volume, and monocyte infiltration. Unexpectedly, Mol also increased renal malondialdehyde and worsened tubular injury, whereas L-arg had no effect. The increase in renal cortical NF-kappaB activation in AN was not altered by AG, L-NIL, or Mol, but the mRNA expression of monocyte chemoattractant protein-1, interleukin-10, and osteopontin were elevated in these groups. Nitrite release from kidney slices reduced in AN. Treatment with Mol restored renal nitrite release to normal, whereas neither L-arg nor the NOS inhibitors had an effect. It is concluded that endogenous iNOS-derived NO has a protective role against tubulointerstitial injury and cytokine production in AN. However, the pro-oxidant activity of NO donors may limit their potential benefit in proteinuric renal disease.
 ...
PMID:Pharmacologic modulators of nitric oxide exacerbate tubulointerstitial inflammation in proteinuric rats. 1146 42

Anew model of thrombotic microangiopathy (TMA) was previously developed, and it was demonstrated that endothelial nitric oxide (NO) synthase (NOS) is upregulated in glomeruli in this model. It was hypothesized that the synthesis of NO, a potent vasodilator and platelet inhibitory factor, is induced as a defense mechanism. The goal of this study was to clarify the role of NO in this model. Ex vivo experiments using Western blotting and functional assays demonstrated upregulation of endothelial NOS in isolated glomeruli from TMA rats. In in vivo experiments, five groups of rats were studied, including rats with TMA treated with vehicle, N(G)-nitro-L-arginine methyl ester (L-NAME) (a NOS inhibitor), or L-N(6)-(1-iminoethyl)lysine (L-NIL) (a specific inducible NOS inhibitor) and normal control rats treated with vehicle or L-NAME. Blood urea nitrogen levels, BP, urinary nitrate/nitrite excretion, and proteinuria were measured. Histologic assessments using periodic acid-Schiff staining and immunohistologic studies with markers for endothelium, platelets, fibrin, cell proliferation, and apoptosis were also performed. L-NAME inhibition of NO synthesis in rats with TMA resulted in more severe glomerular and tubulointerstitial injury, which was accompanied by thrombus formation and a marked loss of endothelial cells, with more apoptotic cells. These changes were associated with severe renal function deterioration. In contrast, these features were less pronounced in the vehicle- or L-NIL-treated rats with TMA and were absent in the control animals. In conclusion, inhibition of NO production in this model of TMA markedly exacerbated renal injury. The absence of effects with L-NIL treatment suggests a minor role for inducible NOS in this model. These results suggest that production of NO, most likely by endothelial cells, is an important protective mechanism in TMA.
 ...
PMID:Protective role of nitric oxide in a model of thrombotic microangiopathy in rats. 1156 7

An imbalance between production of reactive oxygen species (ROS) and antioxidant defense is involved in the pathogenesis of diverse chronic parenchymatous diseases. To identify the primary site of such increased oxidative stress, a lipophilic ROS-sensitive probe (C11-Bodipy 581/591) is introduced, which allows the visualization and quantification of oxidative injury using confocal fluorescence microscopy in living cells. The properties of this probe are such that its emission wavelength irreversibly shifts from red to green upon oxidation. This probe was used to identify the spatiotemporal distribution of lipid peroxidation in the rat kidney during chronic NOS inhibition, a model associated with hypertension and proteinuria. Chronic NOS inhibition resulted in increased lipid peroxidation in renal tubules but hardly any in glomeruli or blood vessels. This peroxidation preceded the loss of renal function characteristic of the model and was accompanied by parallel changes in thiobarbituric acid reactive substances in the renal cortex. Furthermore, the increase in oxidation was dependent on angiotensin II and NADPH oxidase and prevented by vitamin E. Induction of cytoprotective heat-shock protein 70 preceded lipid peroxidation, rise in BP, or proteinuria. These findings challenge the paradigm that the vascular wall is the source and target of oxidative stress in chronic parenchymatous renal disease associated with hypertension.
 ...
PMID:Visualizing tubular lipid peroxidation in intact renal tissue in hypertensive rats. 1244 19

Diabetic nephropathy is the leading cause of end-stage renal disease in the Western hemisphere. Endothelial dysfunction is the central pathophysiologic denominator for all cardiovascular complications of diabetes including nephropathy. Abnormalities of nitric oxide (NO) production modulate renal structure and function in diabetes but, despite the vast literature, major gaps exist in our understanding in this field because the published studies mostly are confusing and contradictory. In this review, we attempt to review the existing literature, discuss the controversies, and reach some general conclusions as to the role of NO production in the diabetic kidney. The complex metabolic milieu in diabetes triggers several pathophysiologic mechanisms that simultaneously stimulate and suppress NO production. The net effect on renal NO production depends on the mechanisms that prevail in a given stage of the disease. Based on the current evidence, it is reasonable to conclude that early nephropathy in diabetes is associated with increased intrarenal NO production mediated primarily by constitutively released NO (endothelial nitric oxide synthase [eNOS] and neuronal nitric oxide synthase [nNOS]). The enhanced NO production may contribute to hyperfiltration and microalbuminuria that characterizes early diabetic nephropathy. On the other hand, a majority of the studies indicate that advanced nephropathy leading to severe proteinuria, declining renal function, and hypertension is associated with a state of progressive NO deficiency. Several factors including hyperglycemia, advanced glycosylation end products, increased oxidant stress, as well as activation of protein kinase C and transforming growth factor (TGF)-beta contribute to decreased NO production and/or availability. These effects are mediated through multiple mechanisms such as glucose quenching, and inhibition and/or posttranslational modification of NOS activity of both endothelial and inducible isoforms. Finally, genetic polymorphisms of the NOS enzyme also may play a role in the NO abnormalities that contribute to the development and progression of diabetic nephropathy.
 ...
PMID:Role of nitric oxide in diabetic nephropathy. 1525 73


1 2 3 Next >>