Kidney Week

Abstract: TH-PO180

Fibroblast Growth Factor 23 (FGF23) and Cystic Liver Disease in Patients with Autosomal Dominant Polycystic Kidney Disease (ADPKD)

Session Information

• Bone and Mineral Metabolism: Clinical - I
  October 25, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Bone and Mineral Metabolism

• 402 Bone and Mineral Metabolism: Clinical

Authors

• Jovanovich, Anna Jeanette, Denver VA / University of Colorado, Denver, Colorado, United States

Anna Jeanette Jovanovich,

• You, Zhiying, UC Denver, Aurora, Colorado, United States

Zhiying You,

• Gitomer, Berenice Y., Div. Renal Diseases and Hypertension,, Aurora, Colorado, United States

Berenice Y. Gitomer,

• Wolf, Myles, Duke University, Durham, North Carolina, United States

Myles Wolf,

• Salusky, Isidro B., Mattel Children's Hospital, Los Angeles, California, United States

Isidro B. Salusky,

• Chonchol, Michel, University of Colorado, Aurora, Colorado, United States

Michel Chonchol,

• Nowak, Kristen L., University of Colorado Denver: Anschutz Medical Campus, Aurora, Colorado, United States

Kristen L. Nowak,

Background

Previous studies have demonstrated that the cystic liver from ADPKD patients markedly expresses FGF23 mRNA and protein. Epidemiological studies have reported an elevation in circulating FGF23 levels in adult ADPKD patients compared to non-ADPKD patients with similar kidney function. We hypothesize that elevated serum iFGF23 levels are associated with greater increases in cystic liver volume in early ADPKD.

Methods

440 participants with early ADPKD and normal kidney function (mean eGFR 92± 18mL/min/1.73m²) who participated in HALT Study A were included in this analysis. The cross-sectional and longitudinal (5-year) association of iFGF23 with liver volume, measured as baseline total liver volume and change in total liver volume by magnetic resonance imaging, respectively, were evaluated using linear regression models. iFGF23 levels were measured using stored serum samples obtained at baseline

Results

Participants had a mean (SD) age of 37 ± 8 years. Mean (SD) serum phosphate level and the median (IQR) iFGF23 level were 3.4 ± 0.5 mg/dL and 43 (33–56) pg/mL, respectively. The median (IQR) baseline liver volume was 1790 (1572-2088)ml. After adjustment for age, sex, body mass index, randomization group, systolic blood pressure, estimated glomerular filtration rate, urinary albumin excretion, serum calcium, phosphate, parathyroid hormone level and PKD genotype, higher circulating iFGF23 levels were not associated with liver volume at baseline (ß=35.39, [95% CI -86.75 to 157.53; p=0.60] per doubling in iFGF23). Similarly, higher circulating iFGF23 was not associated with greater percentage increase in liver volume (ß=-1.94, [95% CI -17.04 to 13.15; p=0.80])per doubling in iFGF23.

Conclusion

Our results indicate that circulating iFGF23 is not independently associated with liver volume in ADPKD patients. FGF23 does not appear to represent a valid therapeutic target or a pertinent biomarker for liver cysts progression in patents with early ADPKD.

Funding

• NIDDK Support