Kidney Week

Abstract: SA-PO369

Kidney Produces Fibroblast Growth Factor 23 in Rat CKD Model

Session Information

• CKD: Risk Factors for Incidence and Progression - III
  November 04, 2017 | Location: Hall H, Morial Convention Center
  Abstract Time: 10:00 AM - 10:00 AM

Category: Chronic Kidney Disease (Non-Dialysis)

• 301 CKD: Risk Factors for Incidence and Progression

Authors

• Sugiura, Hidekazu, Saiseikai Kurihashi Hospital, Saitama, Japan

Hidekazu Sugiura,

• Nagano, Nobuo, Hidaka-kai, Takasaki-shi, Japan

Nobuo Nagano,

• Nitta, Kosaku, Tokyo Women's Medical University, Shinjuku-ku, Japan

Kosaku Nitta,

• Tsuchiya, Ken, Tokyo Women's Medical University, Shinjuku-ku, Japan

Ken Tsuchiya,

Background

Fibroblast growth factor 23 (FGF23) is a hormone secreted from the bone, and involved in phosphorus metabolism. FGF23 mainly bounds to the fibroblast growth factor receptor, which is accompanied by αKlotho expressed in the kidney or parathyroid, and regulates the expression of phosphate co-transporter, production of 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), and secretion of parathyroid hormone (PTH). In chronic kidney disease (CKD), blood FGF23 level rises, which is believed to associated with cardiac hypertrophy and mortality.

Methods

In this study, we chose unilateral nephrectomy rat fed with high-phosphorus diet, 5/6 nephrectomy rat and doxorubicin renal failure rat as CKD model animals, and analyzed expression of renal FGF23 in each CKD model animal by real-time PCR and Western blot analysis.

Results

All model rats showed renal dysfunction and increased level of blood phosphorus. In both unilateral nephrectomy rat fed with high-phosphorus diet and 5/6 nephrectomy rat, blood FGF23 and PTH level were increased. However, level of 1,25(OH)₂D₃ was increased in unilateral nephrectomy rat fed with high-phosphorus diet and decreased in 5/6 nephrectomy rat. In all three model animals, mRNA expression of αKlotho, Na-dependent phosphate co-transporter type IIa and type IIc were decreased in kidneys. FGF23 mRNA was also measured in kidney. While FGF23 mRNA expression in kidney was barely detectable in control groups, it was detectable in CKD model groups. The difference between two groups was statistically significant. In unilateral nephrectomy rat fed with high-phosphorus diet and 5/6nephrectomy rat, Western blot showed the level of renal FGF23 protein was increased.

Conclusion

This result suggests that FGF23 is expressed in kidney of the CKD model rat. FGF23 produced in kidney is suggested to affect the phosphorus metabolism in the kidney.
We demonstrated in this study that FGF23 is produced in the kidney in CKD model rats.

Funding

• Government Support - Non-U.S.