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.
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 compared the clinical characteristics, histological findings, and genotypes of the angiotensin-converting enzyme (ACE) gene and plasminogen activator inhibitor-1 gene between IgAN and N-IgAN patients.
Human proximal tubular epithelial cells (PTEC) were pretreated with PPAR-gamma agonist, rosiglitazone, and/or angiotensin II (AngII) type 1 receptor (ATR1) blocker (ARB), losartan, followed by activation with the conditioned medium collected from human mesangial cells incubated with pIgA1 (IgA-HMC) from patients with IgAN.
Our experimental data together with the meta-analysis suggest TGFB1 as an important candidate gene for further biological studies of IgA nephropathy and as a possible target for therapy.
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.
The investigated polymorphisms were not associated with the progression of the IgA nephropathy, as shown by the similar genotype distribution in group A and group B (slow progressors: TGF-beta1, 92.3%; TNFalpha, 25.6%; IL-6, 74.4%; fast progressors: TGF-beta1, 85.7%; TNFalpha, 22.4%; IL-6: 81.6%, ns).
The investigated polymorphisms were not associated with the progression of the IgA nephropathy, as shown by the similar genotype distribution in group A and group B (slow progressors: TGF-beta1, 92.3%; TNFalpha, 25.6%; IL-6, 74.4%; fast progressors: TGF-beta1, 85.7%; TNFalpha, 22.4%; IL-6: 81.6%, ns).
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.
Given that IgAN is usually characterized by mesangioproliferative glomerulonephritis and that PDGF-B is of central pathophysiological relevance in this process, we analyzed four single-nucleotide polymorphisms (SNPs) of the PDGF-B gene to evaluate a possible association of these SNPs with disease onset and progression, histological grading and responses to ACE inhibitor (ACEi) therapy.
To clarify whether TGF-beta1 contributes to the progression of IgA nephropathy by activating apoptosis in glomerular cells, we examined the expression of TGF-beta1 gene and apoptotic changes in kidney biopsy samples, and assessed those relations to the severity of nephropathy.
Our study suggests that the haplotype reconstruction of TGF-beta1 gene polymorphisms could be more informative than the investigation of single nucleotide polymorphisms for defining the associated risk of developing IgAN.
Although a close relationship between increased renal tissue levels of TGF-beta1 and fibronectin has been reported in IgA nephropathy, no data are available on renal tissue expression of Rho proteins.
The current approach to suppress the effects of angiotensin II, by angiotensin-converting enzyme inhibitors, angiotensin II receptor type 1 blockers, or both, as a cornerstone of the therapy of IgA nephropathy has been strengthened by recent studies.