AT1 receptor antagonism led to decreased expression of pro-fibrotic and pro-inflammatory factors in the kidney.

<p>Quantitative RT-PCR analysis of the expression of fibrogenic factors such as collagen type I chain a1 (A) and FSP-1 (B) in the renal cortex and urinary excretion of the pro-inflammatory factor MCP-1 (C) in wild type and RenTg mice before and after irbesartan treatment. Note the substantial decrease of these factors following AT1 receptor antagonism. Values are mean±SEM; n = 5, 9 and 13 for wild type and RenTg mice before and after irbesartan, respectively; * P<0,05 or ** P<0,01 vs WT; ^## P<0,01 vs RenTg.</p

Therapy with AT1 receptor antagonist led to reappearance of proteins characterizing normal function of proximal tubules.

<p>Representative examples of the expression of proteins typical of the structure and function of proximal tubules such as E-cadherin and megalin. E-cadherin immunostaining in wild type (A) and RenTg mice before (B) and after (C) irbesartan treatment. Quantification by morphometric analysis is presented in D. Megalin expression in wild type (E) and RenTg mice before (F) and after (G) irbesartan treatment. Quantification by morphometric analysis is presented in H. Note that the blunted expression of both proteins in RenTg mice was increased to normal levels following treatment with the AT1 receptor antagonist. Bar = 200 µm. Values are mean±SEM; n = 5, 9 and 13 for wild type and RenTg mice before and after irbesartan, respectively; ** P<0,01 vs WT; ^# P<0,05 or ^## P<0,001 vs RenTg.</p

Improvement of renal histology following AT1 receptor antagonism.

<p>Representative example of renal cortical histology revealed by Mason's trichrome in 12 month old wild type (A) and RenTg mice before (B) and after (C) 6 weeks of irbesartan administration. Note the substantial improvement of the renal histology following therapy with the AT1 receptor antagonist. Bar = 200 µm.</p

Reestablishment of normal podocyte phenotype after AT1 receptor antagonism.

<p>Quantitative RT-PCR analysis of the expression of genes involved in the podocyte structure such as podocin (A) and nephrin (B) in the renal cortex of wild type and RenTg mice before and after irbesartan treatment, and representative examples of podocin expression in glomeruli of wild type (C) and RenTg mice before (D) and after (E) irbesartan treatment. The expressions of podocin and nephrin in the RenTg mice returned to control values following irbesartan administration. Bar = 50 µm. Values are mean±SEM; n = 5, 9 and 13 for wild type and RenTg mice before and after irbesartan, respectively; ** P<0,01 vs WT; ^## P<0,001 vs RenTg.</p

Expression of BMPs and their endogenous inhibitors during progression and reversal of chronic kidney disease.

<p>Quantitative RT-PCR analysis of BMP6 (A) and BMP7 (B) and their endogenous inhibitors noggin (C) and USAG-1 (D) in the renal cortex of wild type and RenTg mice before and after irbesartan treatment. Note that while the expression of BMPs did not change, the expression of their endogenous antagonists noggin and USAG-1 was increased in RenTg and decreased to normal levels following treatment with the AT1 receptor antagonist. Values are mean±SEM; n = 5, 9 and 13 for wild type and RenTg mice before and after irbesartan, respectively; * P<0,05 or ** P<0,01 vs WT; ^# P<0,05 or ^## P<0,001 vs RenTg.</p

Expression of pro-fibrotic genes of the TGFβ family is substantially decreased following AT1 receptor antagonism.

<p>Quantitative RT-PCR analysis of the expression of the pro-fibrotic genes TGFβ (A), CTGF (B) and LTBP4 (C) in the renal cortex of wild type and RenTg mice before and after irbesartan treatment, and TGFβ immunostaining in wild type (D) and RenTg mice before (E) and after (G) irbesartan treatment. Note that the increased expression of pro-fibrotic genes in RenTg mice was decreased to normal levels following treatment with the AT1 receptor antagonist. Values are mean±SEM; n = 5, 9 and 13 for wild type and RenTg mice before and after irbesartan, respectively; * P<0,05 vs WT; ^# P<0,05 or ^## P<0,001 vs RenTg. Bar = 200 µm.</p

List of the primers used for the Real Time-PCR of the different genes as mentioned in the results section.

<p>List of the primers used for the Real Time-PCR of the different genes as mentioned in the results section.</p

Restoration of podocyte structure following AT1 receptor antagonism.

<p>Representative examples of ultrastructural analysis performed by electron microscopy in wild type (A) and RenTg mice before (B) and after (C) irbesartan treatment. The structural alterations of podocytes in RenTg mice such as loss of podocyte foot processes and abnormal thickness of the basal membrane (B) were substantially improved after antagonism of the AT1 receptor (C). Bar = 2 µm.</p

Decrease of renal fibrosis during AT1 receptor antagonism.

<p>Representative example of fibrillar collagen content in the renal interstitium revealed by Sirius red staining and polarized light in wild type (A) and RenTg mice before (B) and after (C) irbesartan treatment. Quantification by morphometric analysis is shown on the lower panel (D). Fibrillar collagen content was decreased to normal levels in RenTg mice after irbesartan administration. Values are are mean±SEM; n = 5, 9 and 13 for wild type and RenTg mice before and after irbesartan, respectively; ** P<0,01 vs WT; ^## P<0,01 vs RenTg. Bar = 200 µm.</p

Effect of AT1 receptor antagonism on blood pressure and albuminuria.

<p>Systolic blood pressure remained unchanged whereas albuminuria decreased to almost normal levels in 12 month old RenTg mice during administration of the AT1 receptor antagonist irbesartan; in triangles are shown the values for age-matched wild type controls. Values are mean±SEM; n = 5, 9 and 13 for wild type and RenTg mice before and after irbesartan, respectively; * P<0,05 or ** P<0,01 vs WT; ^## P<0,001 vs RenTg.</p