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Irreversible renal damage after transient renin-angiotensin system stimulation: involvement of an AT1-receptor mediated immune response.

Heijnen BF, Nelissen J, van Essen H, Fazzi GE, Cohen Tervaert JW, Peutz-Kootstra CJ, Mullins JJ, Schalkwijk CG, Janssen BJ, Struijker-Boudier HA - PLoS ONE (2013)

Bottom Line: Additional groups received losartan (20 mg/kg/day) or hydralazine (100 mg/kg/day) treatment between 4-8 weeks.At these ages, subsets of animals were sacrificed and the presence of kidney T-cell subpopulations was investigated by immunohistochemistry and molecular marker analysis.Losartan prevented these effects completely, whereas hydralazine was unable to affect these changes.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands. bart.heijnen@maastrichtuniversity.nl

ABSTRACT
Transient activation of the renin-angiotensin system (RAS) induces irreversible renal damage causing sustained elevation in blood pressure (BP) in Cyp1a1-Ren2 transgenic rats. In our current study we hypothesized that activation of the AT1-receptor (AT1R) leads to a T-cell response causing irreversible impairment of renal function and hypertension. Cyp1a1-Ren2 rats harbor a construct for activation of the RAS by indole-3-carbinol (I3C). Rats were fed a I3C diet between 4-8 weeks of age to induce hypertension. Next, I3C was withdrawn and rats were followed-up for another 12 weeks. Additional groups received losartan (20 mg/kg/day) or hydralazine (100 mg/kg/day) treatment between 4-8 weeks. Rats were placed for 24h in metabolic cages before determining BP at week 8, 12 and 20. At these ages, subsets of animals were sacrificed and the presence of kidney T-cell subpopulations was investigated by immunohistochemistry and molecular marker analysis. The development of sustained hypertension was completely prevented by losartan, whereas hydralazine only caused a partial decrease in BP. Markers of renal damage: KIM-1 and osteopontin were highly expressed in urine and kidney samples of I3C-treated rats, even until 20 weeks of age. Additionally, renal expression of regulatory-T cells (Tregs) was highly increased in I3C-treated rats, whereas the expression of T-helper 1 (Th1) cells demonstrated a strong decrease. Losartan prevented these effects completely, whereas hydralazine was unable to affect these changes. In young Cyp1a1-Ren2 rats AT1R activation leads to induction of an immune response, causing a shift from Th1-cells to Tregs, contributing to the development of irreversible renal damage and hypertension.

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T-cell infiltration as determined by CD3 immunohistochemistry.CD3 staining of kidneys revealed a time-dependent increase of T-cells after stopping the 4 weeks of RAS-stimulation in I3C-treated animals. Losartan completely prevented this rise in T-cells. These results are in line with the data on renal gene expression. The n for each group is presented in the bars of the GSI. GSI, glomerulosclerosis index; I3C, Indole-3-Carbinol; TIS, tubulointerstitial score.
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pone-0057815-g012: T-cell infiltration as determined by CD3 immunohistochemistry.CD3 staining of kidneys revealed a time-dependent increase of T-cells after stopping the 4 weeks of RAS-stimulation in I3C-treated animals. Losartan completely prevented this rise in T-cells. These results are in line with the data on renal gene expression. The n for each group is presented in the bars of the GSI. GSI, glomerulosclerosis index; I3C, Indole-3-Carbinol; TIS, tubulointerstitial score.

Mentions: Renal gene expression of the general T-cell marker CD3 increased gradually and reached statistical significance at 20 weeks of age in the RAS-stimulated rats. At 8 weeks of age losartan-treatment in this group caused a decrease in CD3 expression and completely prevented the rise over time (Fig. 11A). This same pattern was confirmed by immunohistochemical staining (Fig 12). Additionally, Forkhead box protein 3 (FoxP3) expression, a marker of Tregs, was significantly elevated at 8 and 12 weeks but not anymore at 20 weeks of age. Treg function can be addressed by analysis of transforming growth factor β (TGFβ) expression. In RAS-stimulated rats the increase in Tregs did not result in an increased TGFβ expression (8 weeks: 1.13±0.08 versus 1.00±0.03 in the control group; and 12 weeks: 1.00±0.05 versus 1.00±0.08). Besides, RAS-stimulated rats demonstrated a significant decrease in T-box expressed on T-cells (T-bet) expression, a marker of T helper (Th) 1-cells. This decrease was still present 4 weeks later, but disappeared at 20 weeks of age. Losartan treatment completely prevented the effects on Treg- and T-bet expression (Fig. 11B+C). Finally, a marker of Th2-cells, GATA binding protein 3 (GATA3), was only increased in the RAS-stimulated rats which received losartan treatment. After stopping stimulation and treatment GATA3 expression returned back to normal (Fig. 11D). Finally, no differences were observed in renal interleukin (IL)17 expression (Fig. 11E). Despite the decrease in BP, renal expression of CD3, FoxP3 and T-bet was completely unaffected by hydralazine treatment when compared with untreated RAS-stimulated rats (Fig 13).


Irreversible renal damage after transient renin-angiotensin system stimulation: involvement of an AT1-receptor mediated immune response.

Heijnen BF, Nelissen J, van Essen H, Fazzi GE, Cohen Tervaert JW, Peutz-Kootstra CJ, Mullins JJ, Schalkwijk CG, Janssen BJ, Struijker-Boudier HA - PLoS ONE (2013)

T-cell infiltration as determined by CD3 immunohistochemistry.CD3 staining of kidneys revealed a time-dependent increase of T-cells after stopping the 4 weeks of RAS-stimulation in I3C-treated animals. Losartan completely prevented this rise in T-cells. These results are in line with the data on renal gene expression. The n for each group is presented in the bars of the GSI. GSI, glomerulosclerosis index; I3C, Indole-3-Carbinol; TIS, tubulointerstitial score.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585138&req=5

pone-0057815-g012: T-cell infiltration as determined by CD3 immunohistochemistry.CD3 staining of kidneys revealed a time-dependent increase of T-cells after stopping the 4 weeks of RAS-stimulation in I3C-treated animals. Losartan completely prevented this rise in T-cells. These results are in line with the data on renal gene expression. The n for each group is presented in the bars of the GSI. GSI, glomerulosclerosis index; I3C, Indole-3-Carbinol; TIS, tubulointerstitial score.
Mentions: Renal gene expression of the general T-cell marker CD3 increased gradually and reached statistical significance at 20 weeks of age in the RAS-stimulated rats. At 8 weeks of age losartan-treatment in this group caused a decrease in CD3 expression and completely prevented the rise over time (Fig. 11A). This same pattern was confirmed by immunohistochemical staining (Fig 12). Additionally, Forkhead box protein 3 (FoxP3) expression, a marker of Tregs, was significantly elevated at 8 and 12 weeks but not anymore at 20 weeks of age. Treg function can be addressed by analysis of transforming growth factor β (TGFβ) expression. In RAS-stimulated rats the increase in Tregs did not result in an increased TGFβ expression (8 weeks: 1.13±0.08 versus 1.00±0.03 in the control group; and 12 weeks: 1.00±0.05 versus 1.00±0.08). Besides, RAS-stimulated rats demonstrated a significant decrease in T-box expressed on T-cells (T-bet) expression, a marker of T helper (Th) 1-cells. This decrease was still present 4 weeks later, but disappeared at 20 weeks of age. Losartan treatment completely prevented the effects on Treg- and T-bet expression (Fig. 11B+C). Finally, a marker of Th2-cells, GATA binding protein 3 (GATA3), was only increased in the RAS-stimulated rats which received losartan treatment. After stopping stimulation and treatment GATA3 expression returned back to normal (Fig. 11D). Finally, no differences were observed in renal interleukin (IL)17 expression (Fig. 11E). Despite the decrease in BP, renal expression of CD3, FoxP3 and T-bet was completely unaffected by hydralazine treatment when compared with untreated RAS-stimulated rats (Fig 13).

Bottom Line: Additional groups received losartan (20 mg/kg/day) or hydralazine (100 mg/kg/day) treatment between 4-8 weeks.At these ages, subsets of animals were sacrificed and the presence of kidney T-cell subpopulations was investigated by immunohistochemistry and molecular marker analysis.Losartan prevented these effects completely, whereas hydralazine was unable to affect these changes.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands. bart.heijnen@maastrichtuniversity.nl

ABSTRACT
Transient activation of the renin-angiotensin system (RAS) induces irreversible renal damage causing sustained elevation in blood pressure (BP) in Cyp1a1-Ren2 transgenic rats. In our current study we hypothesized that activation of the AT1-receptor (AT1R) leads to a T-cell response causing irreversible impairment of renal function and hypertension. Cyp1a1-Ren2 rats harbor a construct for activation of the RAS by indole-3-carbinol (I3C). Rats were fed a I3C diet between 4-8 weeks of age to induce hypertension. Next, I3C was withdrawn and rats were followed-up for another 12 weeks. Additional groups received losartan (20 mg/kg/day) or hydralazine (100 mg/kg/day) treatment between 4-8 weeks. Rats were placed for 24h in metabolic cages before determining BP at week 8, 12 and 20. At these ages, subsets of animals were sacrificed and the presence of kidney T-cell subpopulations was investigated by immunohistochemistry and molecular marker analysis. The development of sustained hypertension was completely prevented by losartan, whereas hydralazine only caused a partial decrease in BP. Markers of renal damage: KIM-1 and osteopontin were highly expressed in urine and kidney samples of I3C-treated rats, even until 20 weeks of age. Additionally, renal expression of regulatory-T cells (Tregs) was highly increased in I3C-treated rats, whereas the expression of T-helper 1 (Th1) cells demonstrated a strong decrease. Losartan prevented these effects completely, whereas hydralazine was unable to affect these changes. In young Cyp1a1-Ren2 rats AT1R activation leads to induction of an immune response, causing a shift from Th1-cells to Tregs, contributing to the development of irreversible renal damage and hypertension.

Show MeSH
Related in: MedlinePlus