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Intrarenal angiotensin II plays an important role in renal fibrosis in primary IgA nephropathy.

Objective: To investigate the relationship of intrarenal angiotensin II (Ang II) expression with clinicpathological injury index and intrarenal expression and regulation of RAS (renin-angiotensin system) components in IgAN (immunoglobulin A nephropathy) patients.

Material and methods: The expression of intrarenal renin, angiotensinogen (AGT), Ang II, Ang IIreceptor was examined by immunohistochemistry staining (IHCS). Clinic-pathological injury index included blood pressure, estimated glomerular filtration rate (eGFR), proteinuria and Katafuchi score.

Results: Positive IHCS area of intrarenal Ang II was 32.73 ± 14.74%. There was a negative correlation between intrarenal Ang II and eGFR (r=-0.61, P<0.01), index of glomerular hypercellularity (ρ=-0.35, P<0.05).Intrarenal Ang II correlated positively with pathological chronicity index (ρ=0.39, P<0.05), index of interstitial cell infiltration (ρ=0.52, P<0.01), index of tubular atrophy (ρ=0.51, P<0.01), index of vessel wall thickening (ρ=0.36, P<0.05) and index of arteriolar hyalinosis (ρ=0.36, P<0.05). Intrarenal Ang II positively correlated with intrarenal renin and AGT (r=0.43, P<0.01 and r=0.3, P<0.05, respectively). No other correlation was evidenced between intrarenal expression of explored RAS components.

Conclusions: Intrarenal Ang II plays an important role in renal fibrosis in IgAN, particularly at the tubulointerstitial level. Moreover, there is a tight regulation of the intrarenal RAS components in IgAN.

Author(s): Han Wen-lun, Zhu Yun-yun, Zhong Yu, Ding Hui-deng