angiotensinogen and Glomerulonephritis--IGA

To evaluate the association between angiotensinogen (AGT) gene polymorphism and the risk of Henoch-Schönlein purpura (HSP)/Henoch-Schönlein purpura nephritis (HSPN) we searched the eligible studies through Pub Med, Embase, Cochrane, and China National Knowledge Infrastructure (CNKI) databases according to predefined criteria. A random-effects model was used to calculate the combined odds ratios (ORs) and its corresponding 95% confidence interval (CI). Five studies were recruited for the analysis of the association between AGT M235T gene polymorphism and HSP/HSPN risk. M allele was associated with lower risk of HSP in adult (p = 0.050), TT genotype was associated with the susceptibility to HSP in adult (p = 0.039). AGT M235T gene polymorphism was not associated with HSP risk in children. No marked association was observed between AGT M235T gene polymorphism and HSPN risk. No evidence of publication bias was observed. In conclusion, M allele might be a protective factor against the HSP risk in adult, TT genotype might be a risk factor for the susceptibility to HSP in adult. However, further larger studies should be performed in the future.

Topics: Adult; Angiotensinogen; Genetic Predisposition to Disease; Glomerulonephritis, IGA; Humans; IgA Vasculitis; Polymorphism, Genetic; Protective Factors

The association between angiotensinogen (AGT) M235T gene polymorphism and IgA nephropathy (IgAN) risk remains elusive. Our aim was to evaluate the association between AGT M235T gene polymorphism and IgAN susceptibility by performing a meta-analysis. Eligible studies were searched according to predefined criteria using electronic databases. Eight studies were identified for the analysis of the association between AGT M235T gene polymorphism and IgAN risk. M allele/MM genotype were not associated with IgAN risk in overall populations, Caucasians and Asians (overall populations: p = 0.448 and 0.861, Caucasians: p = 0.618 and 0.886, Asians: p = 0.566 and 0.652). TT/MT genotype were not associated with IgAN risk in overall populations, Caucasians and Asians (overall populations: p = 0.703 and 0.454, Caucasians: p = 0.975 and 0.946, Asians: p = 0.697 and 0.353). No evidence of publication bias was observed. In conclusion, AGT M235T gene polymorphism may not be correlated with IgAN susceptibility in overall populations, Caucasians and Asians. However, more studies should be performed in the future.

Topics: Alleles; Angiotensinogen; Asian People; Genetic Association Studies; Genetic Predisposition to Disease; Glomerulonephritis, IGA; Humans; Methionine; Polymorphism, Genetic; Risk Factors; Threonine; White People

Immunoglobulin A (IgA) nephropathy is recognized worldwide as the most common primary glomerulopathy. Although the mechanisms underlying the development of IgA nephropathy are gradually being clarified, their details remain unclear, and a radical cure for this condition has not yet been established. It has been clinically demonstrated that the immunoreactivities of intrarenal heme oxygenase-1 (HO-1) and 4-hydroxy-2-nonenal (4-HNE) markers of reactive oxygen species (ROS) and those of intrarenal angiotensinogen (AGT) and angiotensin II (Ang II) markers of renin angiotensin system (RAS) in IgA nephropathy patients were significantly increased as compared to those of control subjects. In an animal study, high IgA of ddY (HIGA) mice were used as an IgA nephropathy model and compared with BALB/c mice, which served as the control. The levels of markers for ROS (urinary 8-isoprostane and intrarenal 4-HNE), RAS (intrarenal AGT and Ang II), and renal damage in the HIGA mice were significantly increased as compared to those in the BALB/c mice. Moreover, an interventional study using HIGA mice demonstrated that the expressions of 2 lines of intrarenal ROS markers (4-HNE and HO-1), 2 lines of intrarenal RAS markers (AGT and Ang II) and renal damage decreased significantly in HIGA mice receiving treatment with the Ang II receptor blocker olmesartan but not in HIGA mice receiving treatment with RAS-independent antihypertensive drugs (hydralazine, reserpine, and hydrochlorothiazide) when compared with HIGA mice that were not treated. These data suggest that intrarenal ROS and RAS activation plays a pivotal role in the development of IgA nephropathy.

Topics: Aldehydes; Angiotensin II; Angiotensinogen; Animals; Biomarkers; Cysteine Proteinase Inhibitors; Evidence-Based Medicine; Glomerulonephritis, IGA; Heme Oxygenase-1; Humans; Mice; Reactive Oxygen Species; Renin-Angiotensin System; Vasoconstrictor Agents

Blockade of the renin-angiotensin system (RAS), such as angiotensin-converting enzyme inhibitor and/or angiotensin receptor blocker, has been well appreciated as a renoprotective treatment in proteinuric glomerular diseases. However, not all patients with glomerular diseases respond well to this therapy. Single nucleotide polymorphisms (SNPs) in angiotensin-converting enzyme (ACE) and angiotensinogen may be involved in the inter-individual difference in the responsiveness to the renoprotective efficacy of the RAS blockade. This review focuses on the interface between genomics and therapeutics in the renin-angiotensin system in IgA nephropathy, the most prevalent form of primary glomerulonephritis and one of the major causes of end-stage renal disease in the world.

Topics: Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Angiotensinogen; Cytochrome P-450 CYP11B2; Glomerulonephritis, IGA; Humans; Peptidyl-Dipeptidase A; Polymorphism, Genetic; Renin-Angiotensin System

The genes of the renin-angiotensin system and their relation to renal diseases are of great interest. The number of studies examining the role of polymorphism in these genes in development or progression of renal diseases has increased nearly logarithmically, but results remain conflicting. Evidence is increasing that progression of renal disease is more rapid in DD-homozygotes of the angiotensin-converting enzyme gene polymorphism, but other relationships have not been solidly established.

Topics: Angiotensinogen; Diabetic Nephropathies; Disease Progression; Glomerulonephritis, IGA; Humans; Peptidyl-Dipeptidase A; Polymorphism, Genetic; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Receptors, Angiotensin; Renin-Angiotensin System

To explore the relationship between the degree of renal fibrosis in patients with immunoglobulin A nephropathy (IgAN) and their levels of Apelin-12, Average Optical Density of angiotensin II type 1 receptor (AODAT1R), and angiotensinogen (AGT).. A total of 156 patients with IgAN diagnosed by renal biopsy in our hospital were selected and divided into a T0 group (54 cases), T1 group (49 cases) and T2 group (53 cases). The levels of Apelin-12, AT1R, and AGT were compared among the three groups, and the relationship between the above three indicators and degree of renal fibrosis was analyzed among patients with IgAN.. The AODAT1R and AGT level in the T2 group and T1 groups were significantly higher than those of the T0 group, and the Apelin-12 level of patients in the T2 group and T1 groups were significantly lower than that in T0 group. Significances of the same trend were observed among all the above indicators between the T2 group and T1 group. ROC curves showed that when the cutoff value of Apelin-12 was 2.36 µg/L, the area under curve (AUC), sensitivity, and specificity of T0-T1T2 were 0.889, 92.00%, and 88.00%, respectively. When the cut-off value of AODAT1R was 0.065, the AUC, sensitivity, and specificity were 0.706, 76.00%, and 76.00%, respectively, and when the cut-off value of AGT was 47.26 ng/mL, the AUC, sensitivity, and specificity were 0.899, 84.00%, and 88.00%, respectively. When the cutoff value of Apelin-12 was 0.92 µg/L, the AUC, sensitivity, and specificity of T0T1-T2 were 0.819, 84.62%, and 87.50%, respectively, and when the cutoff value of AODAT1R was 0.079, the AUC, sensitivity, and specificity were 0.699, 76.92%, and 79.17%, respectively. When the cut-off value of AGT was 92.96 ng/mL, the AUC, sensitivity, and specificity were 0.893, 84.62%, and 91.67%, respectively.. Apelin-12 decreased with disease progression, while AT1R and AGT increased. The changes of levels of Apelin-12, AT1R, and AGT have certain significance in judging the degree of renal fibrosis in patients with IgA nephropathy, and the change of level of AGT has the highest correlation with the degree of renal fibrosis.

Topics: Angiotensinogen; Fibrosis; Glomerulonephritis, IGA; Humans; Intercellular Signaling Peptides and Proteins; Receptor, Angiotensin, Type 1

Recently, we demonstrated that urinary angiotensinogen (AGT) levels are increased and reflect intrarenal renin-angiotensin system (RAS) status in pediatric patients with chronic glomerulonephritis. Therefore, this study was performed to test the hypothesis that urinary AGT (UAGT) levels provide a specific index of intrarenal RAS status associated with RAS blockade treatment in pediatric IgA nephropathy (IgAN) patients.. We measured plasma and UAGT levels and urinary transforming growth factor beta (TGF-β) levels, after which we performed immunohistochemical analysis of AGT, angiotensin II (Ang II), and TGF-β in 24 pediatric IgAN patients treated with RAS blockades for 2 years. Paired tests were used to analyze the changes from baseline to study end.. Although there was no change in plasma AGT levels, UAGT and TGF-β levels were significantly decreased after RAS blockade, which was accompanied by the expression levels of AGT, Ang II, and TGF-β, as well as the magnitude of glomerular injury. Baseline UAGT levels positively correlated with diastolic blood pressure, urinary protein levels, scores for mesangial hypercellularity, and the expression levels of AGT, Ang II, and TGF-β in renal tissues.. These data indicate that UAGT is a useful biomarker of intrarenal RAS activation, which is associated with glomerular injury during RAS blockade in pediatric IgAN patients.

Topics: Adolescent; Angiotensin II; Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Angiotensinogen; Biomarkers; Biopsy; Child; Enzyme-Linked Immunosorbent Assay; Female; Glomerulonephritis, IGA; Humans; Immunohistochemistry; Kidney; Male; Predictive Value of Tests; Renin-Angiotensin System; Time Factors; Transforming Growth Factor beta; Treatment Outcome; Urinalysis

The mechanism of immunoglobulin A nephropathy (IgAN) remains unclear. Genetic factors may be associated with the risk of IgAN. This study aims to identify the possible association of M268T (rs699) in the Angiotensinogen (AGT) gene and A1166C (rs5186) in the Angiotensin II receptor type 1 (ATR1) gene with IgAN risk.. Study subjects included 351 patients with IgAN and 310 controls from the Chinese population. The tag SNPs (tSNPs) were genotyped by Sequenom MassARRAY RS1000. Statistical analysis of the association between tSNPs and IgAN was performed using the χ(2) test and SNPStats software.. The AGT (M268T) genotypes were distributed in IgAN as CC 61.9%, CT 34.8%, and TT 3.2%, while in controls CC 64.1%, CT 31.3%, and TT 4.6%. Distribution of ATR1 (A1166C) was AA 87.7%, CA 12.3%, and CC 0%, while in controls AA 87.2%, CA 12%, and CC 0.8%. We further analyzed tSNPs under different inheritance models and found that there were no significant differences in the genotypes and allele frequencies of rs699 and rs5186 between two groups (p > 0.05). We also analyzed tSNPs based on the rate of pressure, proteinuria and Lee's classification, and no significant differences were found in the models (p > 0.05).. rs699 in the AGT gene and rs5186 in the ATR1 gene were not associated with the risk and clinical outcomes of IgAN.

Topics: Adult; Angiotensinogen; Asian People; China; Female; Glomerulonephritis, IGA; Humans; Male; Middle Aged; Models, Genetic; Polymorphism, Single Nucleotide; Receptor, Angiotensin, Type 1; Risk Factors

The purpose of our study was to evaluate the correlation of polymorphisms in angiotensinogen (AGT), angiotensin-converting enzyme (ACE), and endothelial nitric oxide synthase (eNOS) genes and the development and prognostic implications for immunoglobulin A nephropathy (IgAN)/membranous nephropathy (MN). A polymerase chain reaction was performed for the AGT, ACE, and eNOS genes, followed by DNA sequencing and statistical analysis. There was a difference in ACE gene type II and type I between the IgAN and MN groups (P < .05) and in eNOS gene TT type and T type between the IgAN and MN groups (P < .05 and P < .01). In the IgAN group, significant differences were observed between ACE gene polymorphism and the age group of 20 years or less, male sex group, with/without hematuria, and high blood urea nitrogen (BUN; P < .05 or P < .01); between AGT gene polymorphism and with/without hematuria, high BUN, and pathologic classification (P < .05 or P < .01); and between eNOS gene polymorphism and high BUN and pathologic classification (P < .05 or P < .01). However, in the MN group, significant differences were observed between ACE gene polymorphism and the degree of proteinuria and high BUN (P < .001 and P < .05), between AGT gene polymorphism and with/without hematuria (P < .05), and between eNOS gene polymorphism and the degree of proteinuria and high BUN (P < .05 and P < .01). The ACE, AGT, and eNOS genes were correlated with the development of renal function failure in IgAN, whereas the ACE and eNOS genes were associated with the degree of proteinuria and the development of renal function failure in MN.

Topics: Adolescent; Adult; Angiotensinogen; Disease Progression; Female; Genetic Association Studies; Genetic Predisposition to Disease; Genotype; Glomerulonephritis, IGA; Glomerulonephritis, Membranous; Humans; Kidney; Male; Middle Aged; Nitric Oxide Synthase Type III; Peptidyl-Dipeptidase A; Polymorphism, Single Nucleotide; Proteinuria

Urinary angiotensinogen (AGT) was reported as a marker of renal injury in chronic kidney disease patients. However, the main source of urinary AGT is unknown in proteinuric patients because the disrupted filtration barrier might cause AGT filtration. We investigated the origin and the clinical importance of urinary AGT in proteinuric IgA nephropathy (IgAN) patients.. In patients with biopsy-proven IgAN, urinary and plasma AGT was measured using a sandwich ELISA and compared with intrarenal AGT expression. The patients were followed up for 3 years.. Natural logarithm of the urinary AGT/creatinine (ln (urinary AGT/Cr)) was positively correlated with intrarenal expression of AGT (ln (urinary AGT/Cr) versus AGT/β-actin, r = 0.620, P < 0.0001; ln (urinary AGT/Cr) versus AGT density, r = 0.452, P = 0.007). Ln (urinary AGT/Cr) showed a positive correlation with urinary protein/creatinine ratio (PCR) but a negative correlation with estimated glomerular filtration rate (eGFR). Regression analyses showed that ln (urinary AGT/Cr) was a significant determinant of urinary PCR and eGFR 3 years after biopsy.. Urinary AGT reflects intrarenal AGT expression and correlates with the extent of proteinuria and renal function. Our study indicates the intrarenal compartment as the main source of urinary AGT, suggesting its clinical implication as an important biomarker in proteinuric IgAN patients.

Topics: Adolescent; Adult; Angiotensinogen; Female; Follow-Up Studies; Glomerulonephritis, IGA; Humans; Male; Middle Aged; Proteinuria; Young Adult

A potential contribution of local activation of the renin-angiotensin system (RAS) to the pathogenesis of renal injury has been indicated by evidence for blood pressure-independent renoprotective effects of angiotensin II (AngII) receptor blockers (ARBs). The present study was performed to test the hypothesis that urinary angiotensinogen provides a specific index of intrarenal RAS status in patients with immunoglobulin A (IgA) nephropathy.. This paper is a survey of urine specimens from three groups: healthy volunteers, patients with IgA nephropathy and patients with minor glomerular abnormality (MGA). Patients with hypertension, diabetes, reduced glomerular filtration rate and/or who were under any medication were excluded from this study. Urinary angiotensinogen levels were measured by a sandwich enzyme-linked immunosorbent assay system.. Urinary angiotensinogen levels were not different between healthy volunteers and patients with MGA. However, urinary angiotensinogen levels, renal tissue angiotensinogen expression and AngII immunoreactivity were significantly higher in patients with IgA nephropathy than in patients with MGA. Baseline urinary angiotensinogen levels were positively correlated with renal angiotensinogen gene expression and AngII immunoreactivity but not with plasma renin activity or the urinary protein excretion rate. In patients with IgA nephropathy, treatment with an ARB, valsartan (40 mg/day), significantly increased renal plasma flow and decreased filtration fraction, which were associated with reductions in urinary angiotensinogen levels.. These data indicate that urinary angiotensinogen is a powerful tool for determining intrarenal RAS status and associated renal derangement in patients with IgA nephropathy.

Topics: Angiotensinogen; Biomarkers; Blood Pressure; Case-Control Studies; Creatinine; Enzyme-Linked Immunosorbent Assay; Female; Glomerular Filtration Rate; Glomerulonephritis, IGA; Humans; Immunoenzyme Techniques; Male; Middle Aged; Renin-Angiotensin System

We demonstrated previously that the blood pressure of patients with IgA nephropathy becomes salt sensitive as renal damage progresses. We also showed that increased urinary angiotensinogen levels in such patients closely correlate with augmented renal tissue angiotensinogen gene expression and angiotensin II levels. Here, we investigated the relationship between urinary angiotensinogen and salt sensitivity of blood pressure in patients with IgA nephropathy. Forty-one patients with IgA nephropathy consumed an ordinary salt diet (12 g/d of NaCl) for 1 week and a low-salt diet (5 g/d of NaCl) for 1 week in random order. The salt-sensitivity index was calculated as the reciprocal of the slope of the pressure-natriuresis curve drawn by linking 2 data points obtained during consumption of each diet. The urinary angiotensinogen:creatinine ratio was significantly higher in patients who consumed the ordinary salt diet compared with the low-salt diet (17.5 μg/g [range: 7.3 to 35.6 μg/g] versus 7.9 μg/g [range: 3.1 to 14.2 μg/g] of creatinine, respectively; P<0.001). The sodium sensitivity index in our patients positively correlated with the glomerulosclerosis score (r=0.43; P=0.008) and changes in logarithmic urinary angiotensinogen:creatinine ratio (r=0.37; P=0.017) but not with changes in urinary protein excretion (r=0.18; P=0.49). In contrast, changes in sodium intake did not alter the urinary angiotensinogen:creatinine ratio in patients with Ménière disease and normal renal function (n=9). These data suggest that the inappropriate augmentation of intrarenal angiotensinogen induced by salt and associated renal damage contribute to the development of salt-sensitive hypertension in patients with IgA nephropathy.

Topics: Adult; Angiotensinogen; Blood Pressure; Female; Glomerulonephritis, IGA; Humans; Kidney; Male; Middle Aged; Renin-Angiotensin System; Retrospective Studies; Sodium Chloride, Dietary

The intrarenal renin-angiotensinogen system (RAS) plays a major role in the progression of chronic kidney disease. Urinary angiotensinogen (UAGT) provides a specific index of the intrarenal RAS status. This study was conducted to find the role of UAGT as a predictive marker in patients with immunoglobulin A nephropathy (IgAN).. Thirty-six patients with IgAN, 14 non-IgAN and 15 healthy controls were included. The UAGT concentration was measured using human ELISA kits and adjusted by urinary creatinine.. UAGT levels were significantly higher in patients with IgAN and non-IgAN than in healthy subjects (104.96 vs. 6.71 ng/mgCr, p < 0.01). Using univariate regression analysis, UAGT was found to correlate with the urine protein-to-creatinine ratio (UPCR), serum creatinine, and systolic and diastolic blood pressure in patients with IgAN. Multivariate regression analysis revealed that UAGT correlated positively with UPCR. Patients with levels of UAGT >100 ng/mgCr showed higher serum creatinine after treatment than patients with UAGT levels <100 ng/mgCr.. This study showed that UAGT levels are increased and correlate positively with the UPCR in IgAN. Patients with high levels of UAGT may have poor renal function following treatment.

Topics: Adult; Angiotensinogen; Biomarkers; Creatinine; Female; Glomerulonephritis; Glomerulonephritis, IGA; Humans; Male; Middle Aged; Proteinuria; Regression Analysis; Renin-Angiotensin System; Retrospective Studies

The intrarenal renin-angiotensin system (RAS) activation plays a pivotal role in immunoglobulin A nephropathy (IgAN) pathogenesis, which is still largely undefined. Recently, vasopressin (AVP) has been advocated to contribute to the genesis and progression of chronic kidney diseases (CKD) directly, and indirectly, via RAS activation. Our aim is to explore the intrarenal activity of AVP, its relationship with RAS activity, as well as its modulation by therapies in IgAN.. In this observational study, we measured plasma copeptin, a surrogate marker of AVP, the urine excretion of aquaporin 2 (AQP2), a protein reflecting renal AVP action, and angiotensinogen (AGT), a parameter of renal RAS activation, and their relationship with renal function in 44 IgAN patients at the time of renal biopsy, without any drug therapy, and after 6-month treatment with ACEi or steroid+ACEi. Twenty-one patients with other CKD and 40 healthy subjects were recruited as controls.. ELISAs were used to measure all variables of interest.. At baseline, IgAN patients showed higher urinary levels of AQP2, compared with controls and patients with other CKD. Urinary AQP2 and AGT levels strongly correlated with the presence of arterial hypertension. Steroids+ACEi caused the decrease of all the variables examined. The fall of urinary AQP2 and AGT following drug treatments was associated with the decrease of daily proteinuria.. Our findings would support the involvement of AVP-AQP2 axis, interacting with the RAS, in the progression of IgAN and candidate AQP2 as a possible novel marker of the disease.

Topics: Adult; Angiotensin-Converting Enzyme Inhibitors; Angiotensinogen; Anti-Inflammatory Agents; Aquaporin 2; Arginine Vasopressin; Biomarkers; Bradykinin; Female; Glomerulonephritis, IGA; Glycopeptides; Humans; Hypertension, Renal; Logistic Models; Male; Middle Aged; Osmolar Concentration; Proteinuria; Renin-Angiotensin System; Steroids

Genetic variability in the renin-angiotensin-aldosterone system may modify renal responses to injury and disease progression. The angiotensin I-converting enzyme (ACE) gene insertion/deletion (I/D), the angiotensinogen (AGT) gene, M235T, the aldosterone synthase (CYP11B2) gene, C-344T, and the angiotensin II type 1 receptor (AT1R) gene, A1166C, have been shown to be associated with IgA nephropathy (IgAN) and its progression. We determined the presence of these polymorphisms in 130 Chinese patients with IgAN, including 47 patients with end-stage renal disease (ESRD) and 120 healthy Chinese subjects, to assess their impact on the susceptibility to disease and the liability of progression to ESRD.. Genotyping was performed with DNA isolated from peripheral leucocytes using polymerase chain reaction amplification of the polymorphic sequence, restriction enzyme digestion, and separation and identification of DNA fragments. Clinical data from renal biopsies were collected.. ACE, AGT, CYP and AT1R genotype distributions were similar in patients with IgAN and in controls. Comparing patients with ESRD (IgAN-ESRD) and those without ESRD (IgAN-non ESRD), there was a significant increase only in the ACE DD genotype (P < 0.05) among the four gene polymorphisms. There was significant dominance of the male (P < 0.05), more marked hypertension (P < 0.01), proteinuria (P < 0.01) and increased serum creatinine during renal biopsy (P < 0.01) in the IgAN-ESRD group.. Among the ACE, AGT, AT1R and CYP gene polymorphisms, only the DD genotype may predispose the individual to increased risk of progression to ESRD in the Chinese population.

Topics: Adult; Angiotensinogen; Asian People; Cytochrome P-450 CYP11B2; Female; Genetic Predisposition to Disease; Genotype; Glomerulonephritis, IGA; Humans; Kidney Failure, Chronic; Male; Middle Aged; Peptidyl-Dipeptidase A; Polymorphism, Genetic; Receptor, Angiotensin, Type 1; Renin-Angiotensin System

We recently reported that urinary excretion rates of angiotensinogen provide a specific index of the intrarenal renin-angiotensin system status in angiotensin II-dependent hypertensive rats. Angiotensinogen concentrations in mouse plasma are thought to be much lower than those in rat plasma; however, detailed information is deficient due to lack of direct quantitative measurements of rodent angiotensinogen. To elucidate this issue, we have developed a quantitative method for measurement of rodent angiotensinogen using a sandwich-type ELISA. The standard curve for mouse and rat angiotensinogen exhibited a high linearity at 0.16-10 and 0.08-5 ng/ml, respectively, with correlation coefficients >0.99. While plasma angiotensinogen concentrations of male high serum IgA (HIGA) mice (IgA nephritis model animals, 1,308 +/- 47 ng/ml; n = 10) were lower than those of control BALB/c mice (1,620 +/- 384; n = 12), urinary angiotensinogen concentrations of HIGA mice (14.6 +/- 1.5 ng/ml; n = 34) were higher than those of BALB/c mice (4.6 +/- 0.1; n = 2). In a similar manner, while plasma angiotensinogen concentrations of Zucker diabetic fatty (ZDF) obese rats (type 2 diabetic model animals, 1,789 +/- 50 ng/ml; n = 5) were lower than those of control ZDF lean rats (2,296 +/- 47; n = 5), urinary angiotensinogen concentrations of ZDF obese rats (88.2 +/- 11.4 ng/ml; n = 15) were higher than those of ZDF lean rats (31.3 +/- 1.9; n = 15). These data indicate that plasma and urinary angiotensinogen concentrations are less in mice than rats. However, these data suggest that urinary angiotensinogen levels are different from plasma angiotensinogen levels in rodents. The development of rodent angiotensinogen ELISA allows quantitative comparisons in mouse and rat angiotensinogen levels in models of hypertension and cardiovascular and kidney diseases.

Topics: Angiotensinogen; Animals; Antibody Specificity; Blotting, Western; Diabetes Mellitus, Type 2; Enzyme-Linked Immunosorbent Assay; Genetic Vectors; Glomerulonephritis, IGA; Immunohistochemistry; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Obesity; Rats; Rats, Wistar; Rats, Zucker; Recombinant Proteins; Renin; Reproducibility of Results

Enhanced intrarenal renin-angiotensin system (RAS) is implicated in the development and progression of renal injury. To investigate whether angiotensinogen (AGT) expression is involved in glomerular RAS activity and glomerular injury, we examined glomerular AGT expression and its correlation with expression of other RAS components, and levels of glomerular injury in samples from patients with immunoglobulin A nephropathy (IgAN) (23) and minor glomerular abnormalities (MGA) (8). Immunohistochemistry showed that AGT protein was highly expressed by glomerular endothelial cells (GEC) and mesangial cells in nephritic glomeruli of IgAN compared with glomeruli of MGA. Levels of glomerular AGT protein were well correlated with levels of glomerular angiotensin II (ang II), transforming growth factor-beta (TGF-beta), alpha-smooth-muscle actin, glomerular cell number, and glomerulosclerosis score but not with those of glomerular angiotensin-converting enzyme and ang II type 1 receptor. Real-time polymerase chain reaction (RT-PCR) and Western blot analyses using cultured human GEC indicated that ang II upregulated AGT messenger ribonucleic acid (mRNA) and protein expression in a dose- and time-dependent manner. These data suggest that activated glomerular AGT expression is likely involved in elevated local ang II production and, thereby, may contribute to increased TGF-beta production and development of glomerular injury in IgAN. Augmentation of GEC-AGT production with ang II stimulation might drive further glomerular injury in a positive-feedback loop.

Topics: Adolescent; Aldehydes; Angiotensin II; Angiotensinogen; Cell Count; Cells, Cultured; Child; Endothelial Cells; Gene Expression; Glomerulonephritis, IGA; Humans; Immunohistochemistry; Kidney Glomerulus; Mesangial Cells; Renin-Angiotensin System; Transforming Growth Factor beta; Vasoconstrictor Agents

This study was performed to determine whether immunoreactivity of intrarenal hemeoxygenase-1 and angiotensinogen are increased in IgA nephropathy (IgAN) patients. Hemeoxygenase-1 and angiotensinogen immunoreactivity were determined by immunohistochemistry robot system in renal specimens from 39 patients with IgAN. Normal portions of surgically resected kidney served as controls. IgAN patients showed moderate proteinuria (1.1+/-0.2 g/day); however, the control group did not show any proteinuria. Immunoreactivity of intrarenal hemeoxygenase-1 and angiotensinogen in IgAN were significantly increased compared to normal kidneys (2.42+/-0.42 vs 1.00+/-0.26 for hemeoxygenase-1 and 4.05+/-0.40 vs 1.00+/-0.21 for angiotensinogen, arbitrary unit). Even though these IgAN patients did not show massive renal damage, hemeoxygenase-1 and angiotensinogen immunoreactivity were increased in these patients at this time point. These data suggest that activated intrarenal reactive oxygen species-angiotensinogen axis plays some roles in development of IgAN at the early stage and will provide supportive foundation of effectiveness of the renin-angiotensin system blockade in IgAN.

Topics: Adult; Angiotensinogen; Female; Glomerulonephritis, IGA; Heme Oxygenase-1; Humans; Kidney; Male; Middle Aged; Oxidative Stress; Proteinuria; Reactive Oxygen Species

We have previously reported that the TT genotype of the angiotensinogen gene and the ID/DD genotype of the angiotensin-converting enzyme gene are associated with increased severity of proteinuria in IgA nephropathy in Japanese children. Recently it was reported that polymorphism at -20 from adenine to cytosine in the angiotensinogen gene, increasing the level of this transcript, was associated with the progression of renal dysfunction in adult IgA nephropathy. We therefore investigated whether this polymorphism is involved in IgA nephropathy in Japanese children. We identified this polymorphism in 105 children with IgA nephropathy and 119 healthy adults using polymerase chain reaction/restriction fragment length polymorphism analysis. At the time of biopsy, all patients had normal blood pressure and renal function. There were no differences in the genotypes and allele frequencies of this polymorphism between patients with IgA nephropathy and controls. The number of patients with the AC/CC genotype showing heavy proteinuria (>or=1.0 g/day per m(2) body surface area) at biopsy was significantly higher than that with the AA genotype ( P=0.039, chi-squared test). The AC/CC genotype of this polymorphism may be associated with an increased severity of proteinuria, suggesting that this polymorphism may play a significant role in the progression of IgA nephropathy in Japanese children.

Topics: Adenine; Adolescent; Angiotensinogen; Asian People; Case-Control Studies; Child; Cytosine; Female; Genotype; Glomerulonephritis, IGA; Humans; Male; Polymorphism, Genetic; Polymorphism, Restriction Fragment Length; Proteinuria

Gene polymorphisms in angiotensin-converting enzyme (ACE), angiotensinogen (AGT) and angiotensin II type 1 receptor (ATR) had been associated with IgA nephropathy (IgAN) and its progression. Several studies on Caucasian and Japanese had reported contradicting results. We determined these polymorphisms in 118 Chinese patients with IgAN and 94 healthy Chinese to assess their clinical impact.. Genotyping was performed with DNA from peripheral leukocytes, PCR amplification of the polymorphic sequence, restriction enzymes digestion, separation and identification of DNA fragments. Clinical data at renal biopsy and final status on renal function were determined from patients' records.. Among controls, genotype distributions were in Hardy-Weinberg equilibrium. Comparing all IgAN patients with controls, AGT and ATR genotype distributions were similar whereas there was significant increase in the ACE DD genotype (p < 0.05). Comparing patients with end-stage renal failure (IgAN-ESRF) and without (IgAN-nonESRF), there was no difference in any of the three gene polymorphisms. But in contrast, there were significant differences in higher male prevalence (p < 0.05), increased serum creatinine at presentation (p < 0.05), more sclerosis (p < 0.01) and higher tubulointerstitial lesion score (p < 0.001) in the IgAN-ESRF group.. Among the ACE, AGT and ATR gene polymorphisms, only the DD genotype may predispose the individual to IgAN in our Chinese population. In contrast to clinical and histological risk factors, these genetic variations showed no impact on disease progression to ESRF. It is unlikely that genotyping more patients will prove these genes useful. Nevertheless, preclinically determined genetic markers are very useful as risk factors for disease occurrence and as prognostic indices for disease progression. Therefore, continuing efforts should be made to look at other genes to find those with significance.

Topics: Adult; Angiotensinogen; China; Disease Progression; Female; Genetic Predisposition to Disease; Glomerulonephritis, IGA; Humans; Kidney Failure, Chronic; Male; Middle Aged; Peptidyl-Dipeptidase A; Polymorphism, Genetic; Receptor, Angiotensin, Type 1; Renin-Angiotensin System; Singapore

The renin-angiotensin system (RAS) seems to play a pivotal role in progression of immunoglobulin A (IgA) nephropathy (IgAN). Accordingly, in patients with IgAN a relationship between the RAS and the fibrogenic cascade triggered by transforming growth factor-beta1 (TGF-beta1) should be observed. This study was carried out to obtain deeper insight into the regulation of RAS and the interaction with TGF-beta1 in the diseased kidney.. Twenty renal biopsies from IgAN patients and five from renal cancer patients (controls) were analyzed in both microdissected glomerular and tubulointerstitial compartments by reverse transcription-polymerase chain reaction (RT-PCR). All patients had normal renal function. The expression of the following genes was determined: angiotensinogen (Agtg), renin, angiotensin-converting enzyme (ACE), angiotensin II (Ang II) type 1 and type II (AT1 and AT2 receptors), TGF-beta1, collagen IV (Coll IV), alpha-smooth muscle actin (alpha-SMA). Quantitative data were confirmed for TGF-beta1 and ACE genes by real-time PCR. Results. RAS genes were overexpressed in IgAN patients vs. control subjects. There was no difference between glomerular and tubulointerstitial RAS gene expression levels. On the contrary, the overactivation of fibrogenic cascade genes (TGF-beta1, Coll IV, alpha-SMA) in the tubulointerstitium was observed (TGF-beta1, glomerular 0.14 +/- 0.10 SD; tubulointerstial 0.34 +/- 0.20; P = 0.000) (alpha-SMA, glomerular 0.08 +/- 0.07; tubulointerstitial 0.35 +/- 0.19; P = 0.000) (Coll IV, glomerular 0.12 +/- 0.11; tubulointerstitial 0.22 +/- 0.10; P = 0.03). This fibrogenic cascade seems to be triggered by RAS as indicated by statistically significant correlations between the expression of their respective genes. A direct relationship between the putative Ang II activity and the expression of AT receptor genes was found in the tubulointerstitium, whereas in the glomeruli this relationship was negative. In the interstitium, statistically significant positive relationships emerged between interstitial infiltrates and the gene expression of Agtg, AT1 receptor, Coll IV, and TGF-beta1.. This study demonstrates that a tight regulation of the intrarenal RAS exists in IgAN and that it follows the general rules disclosed in animal models. Moreover, the RAS seems to be activated early in the diseased kidney and it appears that such activation drives inflammation and a parallel stimulation of the TGF-beta fibrogenic loop, particularly at the tubulointerstitial level.

Topics: Adult; Angiotensin II; Angiotensinogen; Case-Control Studies; Collagen Type IV; Fibrosis; Gene Expression; Gene Expression Regulation; Glomerulonephritis, IGA; Humans; Kidney; Kidney Glomerulus; Kidney Tubules; Male; Middle Aged; Receptor, Angiotensin, Type 1; Receptors, Angiotensin; Renin-Angiotensin System; Transforming Growth Factor beta; Transforming Growth Factor beta1

Blockade of the renin-angiotensin system (RAS) is well documented to be renoprotective; however, not all patients with glomerulonephritis respond well to this therapy. The interindividual variation in response to the RAS blockade may be in part genetically determined, whereas the results have been controversial.. We investigated whether the therapeutic efficacy of angiotensin-converting enzyme (ACE) inhibitors and/or angiotensin receptor blocker on renal prognosis is modified by the angiotensinogen gene (AGT) polymorphism in immunoglobulin A nephropathy (IgAN). In total, 259 patients with histologically proven IgAN were analyzed for clinical manifestations, renal survival, and their associations with AGT A(-20)C and M235T.. The renal prognosis of 110 patients, who received ACE inhibitors/angiotensin receptor blocker during their clinical course, was significantly better than those without ACE inhibitors/angiotensin receptor blockers despite higher blood pressures and heavier proteinuria. The Cox proportional hazards regression model showed an increased hazard ratio (HR) for urinary protein (more than 1.0 g/day) of 3.346 (P = 0.0001), hypertension of 1.949 (P = 0.01), deteriorated renal function of 3.040 (P < 0.0001), no ACE inhibitor/angiotensin receptor blocker administration of 2.725 (P = 0.0004), and the T235 and C(-20) haplotype of 1.608 (P = 0.0322). Only in patients carrying at least one M235 and A(-20) haplotype did the administration of ACE inhibitors/angiotensin receptor blockers have no significant effect on the prognosis of renal function (Kaplan-Meier, log rank test, chi2 = 0.700; P = 0.4028), whereas it was significant in patients who had other haplotypes of AGT (chi2 = 11.805; P = 0.0006).. This study provides evidence that the M235T and A(-20)C genotype of AGT can influence the therapeutic efficacy of a RAS blockade on the renal survival in IgAN.

Topics: Adenine; Adult; Alleles; Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Angiotensinogen; Cytoprotection; Female; Gene Frequency; Genetic Variation; Genotype; Glomerulonephritis, IGA; Guanine; Haplotypes; Humans; Kidney; Kidney Diseases; Male; Methionine; Middle Aged; Polymorphism, Genetic; Renin-Angiotensin System; Risk Factors; Threonine

The M235T polymorphism of the angiotensinogen gene (AGT) is associated with an increased risk of primary hypertension, which may then lead to progressive renal disease. Recent studies showed that nucleotide substitution in the 5' upstream core promoter region of AGT affects the basal transcription rate of the gene.. To evaluate the role of AGT polymorphisms in the progression of IgA nephropathy (IgAN), we analyzed the association of A(-20)C and M235T polymorphisms with renal prognosis in histologically-proven IgAN patients using the Kaplan-Meier method and Cox proportional hazards regression model.. The incidence of hypertension during the course was associated with T235, but not with C(-20). The renal survival rate for 137 patients with creatinine clearance (C(Cr)) of 70 mL/min or greater at the time of renal biopsy, and follow-up time of two years or more was significantly lower in the patients with C(-20) (P = 0.008). The Cox proportional hazards regression model showed an increased hazard ratio (HR) for urinary protein (more than 2 g/day) of 28.3 (95% CI, 7.3 to 109.8; P < 0.001), hypertension at the time of renal biopsy of 4.6 (95% CI, 1.8 to 11.9; P = 0.002), and C(-20) of 3.6 (95% CI, 1.5 to 8.7; P = 0.004).. This work provides evidence that the C(-20) polymorphism of AGT, a subset of T235 alleles, is associated with progression of renal dysfunction in IgAN.

Topics: Adult; Angiotensinogen; Disease Progression; Female; Gene Frequency; Genotype; Glomerulonephritis, IGA; Humans; Male; Middle Aged; Polymorphism, Single Nucleotide; Prognosis; Promoter Regions, Genetic; Proportional Hazards Models

We investigated whether polymorphisms of the renin-angiotensin system genes are involved in IgA nephropathy in Japanese children. We identified the M235T polymorphism of the angiotensinogen (AGT) gene, the I/D polymorphisms of the angiotensin-converting enzyme (ACE) gene, and the A1166C polymorphism of the angiotensin II type 1 receptor gene in 95 Japanese children with IgA nephropathy and 99 healthy Japanese adults. There were no differences in the genotype and allele frequencies of these genes between patients with IgA nephropathy and controls. Urinary protein excretion at the time of biopsy was significantly greater in patients with the TT genotype of the AGT gene than in those with the MM/MT genotypes of the AGT gene (1.32 +/- 1.42 versus 0.75 +/- 0.78 g/day; P = 0.01) and in patients with the ID/DD genotypes of the ACE gene than in those with the II genotype of the ACE gene (1.45 +/- 1.50 versus 0.63 +/- 0.56 g/day; P = 0.001). Thus, the TT genotype of the AGT gene and the ID/DD genotype of the ACE gene are associated with increased severity of proteinuria, suggesting that AGT and ACE gene polymorphisms may play a significant role in the progression of IgA nephropathy in Japanese children.

Topics: Adolescent; Alleles; Angiotensinogen; Child; Female; Gene Frequency; Genotype; Glomerulonephritis, IGA; Humans; Kidney; Male; Peptidyl-Dipeptidase A; Polymorphism, Genetic; Proteinuria; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Receptors, Angiotensin; Renin-Angiotensin System

The impact of renin-angiotensin system (RAS) gene polymorphism on the prognosis of IgA nephropathy (IgAN) is still debated. A longitudinal study of renal prognosis in patients with IgAN was conducted to search retrospectively for a genotype-phenotype association between RAS polymorphisms and end-stage renal failure (ESRF). A classification based on serum creatinine (S(cr)) and 24-h proteinuria (24-P) measured at the time of renal biopsy was used to estimate the risk of ESRF in IgAN: stage 1 (S(cr) 150 micromol/L and 24-P < 1 g or S(cr) < or = 150 micromol/L and 24-P > or = 1 g), stage 3 (S(cr) > 150 micromol/L and 24-P > or = 1 g). Deletion/insertion polymorphism (D/I) of the angiotensin I converting enzyme gene, M235T polymorphism (T/M) of the angiotensinogen gene and A1166C polymorphism (C/A) of the angiotensin II type 1 receptor gene were determined in 274 Caucasian men with biopsy-proven IgAN (n = 86, 112, and 76 in stages 1, 2, and 3, respectively). Mean global follow-up was 6 +/- 5 yr after renal biopsy. For stages 1, 2, and 3, ESRF developed in 7 (8. 1%), 39 (34.8%), and 49 (64.4%) cases (P: < 0.0001), 11.7 +/- 4, 5.4 +/- 4, and 2 +/- 2 yr, respectively, after renal biopsy (P: < 0.001). The distributions of the three genotypes into the three stages were similar. Different distributions were observed when patients were grouped by stage and genotype: ID+DD: 72% in stage 1 versus 84.6% in stages 2 + 3 (P: = 0.02; kappa = 0.14); MT+TT: 66.2% in stages 1 + 2 versus 78.9% in stage 3 (P: = 0.04; kappa = 0.09); and AA+AC: 89.9% in stages 1 + 2 versus 97.4% in stage 3 (P: = 0.04; kappa = -0.1). However, with the use of the Cox proportional hazard model, none of the three genotypes was found to have predictive value for renal survival. Compared with S(cr) and 24-P, genotypes DD, TT, and AA are unlikely to serve as clinically useful predictors of ESRF in IgAN.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Angiotensinogen; Child; Genotype; Glomerulonephritis, IGA; Humans; Kidney Failure, Chronic; Longitudinal Studies; Male; Middle Aged; Peptidyl-Dipeptidase A; Polymorphism, Genetic; Predictive Value of Tests; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Receptors, Angiotensin; Retrospective Studies; Survival Analysis

Genetic variability in the renin-angiotensin system may modify renal responses to injury and disease progression. We examined whether the M235T polymorphism of the angiotensinogen (AGT) gene, the insertion/deletion polymorphism of the angiotensin-converting enzyme (ACE) gene, and the A1166--> C polymorphism of the angiotensin II type 1 receptor gene may be associated with disease progression in 168 Caucasian patients with IgA nephropathy. All patients had serial measurements of their creatinine clearance, proteinuria, and blood pressure (mean+/-SD) with a follow-up of 6.1+/-4.7 yr. The genotype frequencies for each gene were consistent with Hardy-Weinberg equilibrium, and were similar to those of 100 Caucasian control subjects. We examined two primary outcomes: (a) the rate of deterioration of Ccr, and (b) the maximal level of proteinuria. We found that patients with the AGT MT (n = 79) and TT (n = 29) genotypes had a faster rate of deterioration of Ccr than those with the MM (n = 60) genotype (i.e., median values, -6.6 and -6.2 vs. -3. 0 ml/min/yr, respectively; P = 0.01 by Kruskal-Wallis test). Similarly, patients with AGT MT and TT genotypes had higher maximal values of proteinuria than those with the MM genotype (i.e., median values, 2.5 and 3.5 vs. 2.0 g/d, respectively; P < 0.02 by Kruskal-Wallis test). Neither the ACE insertion/deletion nor angiotensin II type I A1166--> C gene polymorphism was associated with disease progression or proteinuria in univariate analysis. Multivariant analysis, however, detected an interaction between the AGT and ACE gene polymorphisms with the presence of ACE/DD polymorphism adversely affecting disease progression only in patients with the AGT/MM genotype (P = 0.008). Neither of these gene polymorphisms was associated with systemic hypertension. Our results suggest that polymorphisms at the AGT and ACE gene loci are important markers for predicting progression to chronic renal failure in Caucasian patients with IgA nephropathy.

Topics: Adult; Aged; Angiotensinogen; Blood Pressure; Creatinine; Disease Progression; Female; Genotype; Glomerulonephritis, IGA; Humans; Kidney Function Tests; Male; Middle Aged; Multivariate Analysis; Peptidyl-Dipeptidase A; Polymorphism, Genetic; Proteinuria; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Receptors, Angiotensin; Risk Factors; White People