angiotensinogen and Nephritis--Interstitial

Genes of the renin-angiotensin system (RAS) are involved in the progression of renal failure. Among them, the angiotensin-converting enzyme (ACE), angiotensinogen (AGT) and angiotensin II type 1 receptor (AT1R) genes are of particular interest. We examined polymorphisms of these three genes for association with the development of interstitial nephritis and progression to end-stage renal failure. The allele frequency and genotype distribution were compared in 90 patients with interstitial nephritis and 200 healthy controls. DNA samples were genotyped by polymerase chain reaction (PCR). We did not find statistically significant differences between groups in the insertion/deletion polymorphism of the ACE gene. An involvement of M235T polymorphism of the AGT gene in renal disease was observed in our study. The frequency of the T allele was higher in patients than in controls (32% vs. 24%). In the A1166C AT1R polymorphism the homozygous CC genotype was also more frequent in interstitial nephritis patients (7% vs. 3.5%). In patients carrying the C allele, an average time to ESRD was significantly shorter than in subjects with the AA genotype. Our study shows the association of the AGT and AT1R gene polymorphisms with the development and progression of interstitial nephritis. The C allele of the A1166C polymorphism appears to be a risk factor for faster disease progression.

Topics: Adult; Angiotensin I; Angiotensinogen; Disease Progression; Female; Gene Expression Regulation; Genetic Predisposition to Disease; Genetic Variation; Humans; Kidney Failure, Chronic; Male; Middle Aged; Nephritis, Interstitial; Polymorphism, Genetic; Receptor, Angiotensin, Type 1; Renin-Angiotensin System; Risk Assessment; Statistics as Topic

Chronic renal failure (CRF) is a complex phenotype that results from an underlying kidney disease and superimposing environmental and genetic factors. The aim of our study was to evaluate the role of polymorphisms in the genes encoding for components of the renin-angiotensin system (RAS) in the development and/or progression of CRF.. Two hundred forty-seven family trios (patients with CRF and both parents; 120 with primary chronic glomerulonephritis, 80 with interstitial nephritis, and 47 with type 1 diabetes with nephropathy) were examined, and transmission/disequilibrium test (TDT) was used to evaluate allele transmission from heterozygous parents to affected offspring.. The D allele of the angiotensin I-converting enzyme (ACE) gene insertion/deletion polymorphism was transmitted significantly more frequently than expected for no association among all examined trios and in the subgroup of patients with interstitial nephritis. The angiotensinogen 235T allele was transmitted significantly more frequently to patients with CRF than expected for no association, but the effect was seen only in patients with interstitial nephritis. The presence of the DD or ID genotype was associated with a faster rate of decline of renal function, which was not observed for the angiotensinogen M235T polymorphism. For chymase gene and angiotensin II receptor type 1 gene, allele transmission did not deviate significantly from a random proportion of 50:50%.. The results of this study suggest that ACE gene insertion/deletion and angiotensinogen M235T polymorphisms contribute to the increased risk for the development of CRF, but the magnitude of the effect within subsets of patients with specific etiologies of CRF must be evaluated further.

Topics: Adolescent; Adult; Alleles; Angiotensinogen; Creatinine; Family Health; Female; Gene Deletion; Genetic Predisposition to Disease; Genotype; Humans; Kidney Failure, Chronic; Male; Nephritis, Interstitial; Peptidyl-Dipeptidase A; Polymorphism, Single Nucleotide; Risk Factors

Enhanced intrarenal angiotensin II (Ang II) activity may contribute to diabetic nephropathy. The proximal tubule is a proposed site of significant intrarenal Ang II production. We determined the effect of early diabetes on mRNA expression of components of the proximal tubule renin-angiotensin system.. Three groups of male Sprague-Dawley rats were studied after two weeks: (1) control (C), (2) streptozotocin-induced diabetes (STZ), and (3) STZ-induced diabetes, with normoglycemia maintained by insulin implants (STZ-I). Competitive reverse transcription-polymerase chain reaction was used to assay mRNA for renin, angiotensinogen, and angiotensin-converting enzyme in suspensions of proximal tubules; plasma and kidney levels of Ang II were measured by radioimmunoassay, and Western analysis of Ang II subtype 1 (AT1) receptors was performed.. STZ rats tended to have increased plasma and intrarenal levels of Ang II compared with C and STZ-I rats. In proximal tubules, mRNA for renin was significantly increased in STZ rats, with reversal to control values in STZ-I rats (C, 2432 +/- 437 vs. STZ, 5688 +/- 890 fg/0.25 microg RNA, P < 0.05 vs. C, N = 9, vs. STZ-I, 1676 +/- 376 fg/0.25 microg RNA, P = NS vs. C). In STZ rats, the AT1 receptor antagonist losartan caused a further fivefold increase in proximal tubule renin mRNA, associated with proximal tubular renin immunostaining. STZ had no significant effect on mRNA expression for angiotensinogen or angiotensin-converting enzyme in proximal tubules. By Western blot analysis, cortical and proximal tubule AT1 receptor protein expression was significantly decreased in STZ rats.. These data suggest activation of the proximal tubule renin-angiotensin system in early STZ diabetes, mediated at least partly by enhanced expression of renin mRNA. Increased local production of Ang II could contribute to tubulointerstitial injury in this model.

Topics: Angiotensin II; Angiotensin Receptor Antagonists; Angiotensinogen; Animals; Antihypertensive Agents; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Gene Expression; Hypertrophy; Hypoglycemic Agents; Insulin; Kidney Tubules, Proximal; Losartan; Male; Nephritis, Interstitial; Rats; Rats, Sprague-Dawley; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Receptors, Angiotensin; Renin; Renin-Angiotensin System; RNA, Messenger