scholarly journals Fractional Excretion of Phosphorus Modifies the Association between Fibroblast Growth Factor-23 and Outcomes

2013 ◽  
Vol 24 (4) ◽  
pp. 647-654 ◽  
Author(s):  
Julie R. Dominguez ◽  
Michael G. Shlipak ◽  
Mary A. Whooley ◽  
Joachim H. Ix
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Fibroblast Growth Factor 23 ◽  
Fractional Excretion ◽  
Fibroblast Growth

scholarly journals Ubiquitin COOH-terminal hydrolase L1 deletion is associated with urinary α-klotho deficiency and perturbed phosphate homeostasis

2018 ◽  
Vol 315 (2) ◽  
pp. F353-F363 ◽  
Author(s):  
Naomi C. Boisvert ◽  
Chet E. Holterman ◽  
Alexey Gutsol ◽  
Josée Coulombe ◽  
Wanling Pan ◽  
...  
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Sodium Phosphate ◽  
Fibroblast Growth Factor 23 ◽  
Fractional Excretion ◽  
Mrna Levels ◽  
Fibroblast Growth ◽  
Wild Type ◽  
Phosphate Homeostasis ◽  
Renal Brush Border Membrane

Loss of ubiquitin COOH-terminal hydrolase L1 (UCHL1), a deubiquitinating enzyme required for neuronal function, led to hyperphosphatemia accompanied by phosphaturia in mice, while calcium homeostasis remained intact. We therefore investigated the mechanisms underlying the phosphate imbalance in Uchl1−/− mice. Interestingly, phosphaturia was not a result of lower renal brush border membrane sodium-phosphate cotransporter expression as sodium-phosphate cotransporter 2a and 2c expression levels was similar to wild-type levels. Plasma parathyroid hormone and fibroblast growth factor 23 levels were not different; however, fibroblast growth factor 23 mRNA levels were significantly increased in femur homogenates from Uchl1−/− mice. Full-length and soluble α-klotho levels were comparable in kidneys from wild-type and Uchl1−/− mice; however, soluble α-klotho was reduced in Uchl1−/− mice urine. Consistent with unchanged components of 1,25(OH)2D3 metabolism (i.e., CYP27B1 and CYP24A1), sodium-phosphate cotransporter 2b protein levels were not different in ileum brush borders from Uchl1−/− mice, suggesting that the intestine is not the source of hyperphosphatemia. Nonetheless, when Uchl1−/− mice were fed a low-phosphate diet, plasma phosphate, urinary phosphate, and fractional excretion of phosphate were significantly attenuated and comparable to levels of low-phosphate diet-fed wild-type mice. Our findings demonstrate that Uchl1-deleted mice exhibit perturbed phosphate homeostasis, likely consequent to decreased urinary soluble α-klotho, which can be rescued with a low-phosphate diet. Uchl1−/− mice may provide a useful mouse model to study mild perturbations in phosphate homeostasis.

scholarly journals Fibroblast Growth Factor-23 (FGF-23) Levels Differ Across Populations by Degree of Industrialization

2016 ◽  
Vol 101 (5) ◽  
pp. 2246-2253 ◽  
Author(s):  
Shennin N. Yuen ◽  
Holly Kramer ◽  
Amy Luke ◽  
Pascal Bovet ◽  
Jacob Plange-Rhule ◽  
...  
Keyword(s):  
United States ◽  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Fibroblast Growth Factor 23 ◽  
Fractional Excretion ◽  
The United States ◽  
Fibroblast Growth ◽  
Phosphate Intake ◽  
Dietary Phosphate ◽  
Fractional Excretion Of Phosphate

Abstract Context: Compensatory increases in fibroblast growth factor 23 (FGF23) with increasing phosphate intake may adversely impact health. However, population and clinical studies examining the link between phosphate intake and FGF23 levels have focused mainly on populations living in highly industrialized societies in which phosphate exposure may be homogenous. Objective: The objective of the study was to contrast dietary phosphate intake, urinary measures of phosphate excretion, and FGF23 levels across populations that differ by the level of industrialization. Design: This was a cross-sectional analysis of three populations. Setting: The study was conducted in Maywood, Illinois; Mahé Island, Seychelles; and Kumasi, Ghana. Participants: Adults with African ancestry aged 25–45 years participated in the study. Main Outcome: FGF23 levels were measured. Results: The mean age was 35.1 (6.3) years and 47.9% were male. Mean phosphate intake and fractional excretion of phosphate were significantly higher in the United States vs Ghana, whereas no significant difference in phosphate intake or fractional excretion of phosphate was noted between the United States and Seychelles for men or women. Overall, median FGF23 values were 57.41 RU/mL (interquartile range [IQR] 43.42, 75.09) in the United States, 42.49 RU/mL (IQR 33.06, 55.39) in Seychelles, and 33.32 RU/mL (IQR 24.83, 47.36) in Ghana. In the pooled sample, FGF23 levels were significantly and positively correlated with dietary phosphate intake (r = 0.11; P < .001) and the fractional excretion of phosphate (r = 0.13; P < .001) but not with plasma phosphate levels (r = −0.001; P = .8). Dietary phosphate intake was significantly and positively associated with the fractional excretion of phosphate (r = 0.23; P < .001). Conclusion: The distribution of FGF23 levels in a given population may be influenced by the level of industrialization, likely due to differences in access to foods preserved with phosphate additives.

Sex and iron modify fibroblast growth factor 23 concentrations in 1-year-old children

2017 ◽  
Author(s):  
Elisa Holmlund-Suila ◽  
Maria Enlund-Cerullo ◽  
Saara Valkama ◽  
Helena Hauta-alus ◽  
Jenni Rosendahl ◽  
...  
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Fibroblast Growth Factor 23 ◽  
Fibroblast Growth
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