Abstract: FR-PO410

Intrarenal Renin-Angiotensin System Activation in Nighttime Is Associated with Renal Arteriosclerosis in Normotensive IgA Nephropathy Patients

Session Information

Category: Chronic Kidney Disease (Non-Dialysis)

  • 301 CKD: Risk Factors for Incidence and Progression

Authors

  • Ohashi, Naro, Hamamatsu University School of Medicine, Hamamatsu, Japan
  • Isobe, Shinsuke, Hamamatsu University School of Medicine, Hamamatsu, Japan
  • Matsuyama, Takashi, Hamamatsu University School of Medicine, Hamamatsu, Japan
  • Ishigaki, Sayaka, Hamamatsu University School of Medicine, Hamamatsu, Japan
  • Tsuji, Naoko, Hamamatsu University School of Medicine , Hamamatsu, Japan
  • Fujikura, Tomoyuki, Hamamatsu University School of Medicine, Hamamatsu, Japan
  • Tsuji, Takayuki, Hamamatsu University School of Medicine, Hamamatsu, Japan
  • Kato, Akihiko, Hamamatsu University School of Medicine, Hamamatsu, Japan
  • Yasuda, Hideo, Hamamatsu University School of Medicine, Hamamatsu, Japan
Background

Intrarenal renin-angiotensin system (RAS) activation especially in nighttime plays an important role in the development of hypertension and renal damage. However, the association between intrarenal RAS activation in daytime and nighttime and renal structural damages has not been clearly investigated in IgA nephropathy patients without hypertension.

Methods

We investigated the urinary angiotensinogen (U-AGT) excretion in daytime and nighttime that reflects intrarenal RAS activity and renal structural damages in 27 normotensive IgA nephropathy patients (age 39.2 ± 13.6 years, 10 men and 17 women, blood pressure 112.0 ± 11.8 / 70.0 ± 9.5 mmHg, estimated glomerular filtration rate (eGFR) 74.0 ± 17.3 ml/min/1.73m2, urinary protein excretion 0.58 ± 0.50 g/day). Renal structural damages of renal biopsy tissues were scored as follows: the levels of arteriolar hyalinosis; the proportion of arterioles affected (0: absent, 1: 1-25%, 2: 26-50%, 3: 51-100%), the levels of arteriosclerosis in arcuate and interlobular arteries (0: normal, 1: intima thickness and less than media thickness, 2: intima thickness and more than media thickness), and percentages of global sclerosis (GS) and tubulointerstitial fibrosis, as described previously.

Results

The levels of arteriosclerosis were significantly and positively associated with U-AGT excretion levels in daytime and nighttime. On the other hand, the levels of arteriolar hyalinosis and percentages of GS and tubulointerstitial fibrosis were not correlated with the U-AGT excretion levels in daytime and nighttime. Multiple liner regression analysis revealed that the levels of arteriosclerosis tended to be associated with U-AGT excretion levels in daytime, when age, sex, body mass index (BMI), and eGFR were adjusted (β=0.33, p=0.079). Moreover, the levels of arteriosclerosis were significantly and positively associated with U-AGT excretion levels in nighttime after adjustment of age, sex, BMI, and eGFR (β= 0.39, p= 0.043).

Conclusion

In normotensive IgA nephropathy patients, the activation of intrarenal RAS especially in nighttime is associated with renal arteriosclerosis.

Funding

  • Government Support - Non-U.S.