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Fibroblast growth factor 23 in hypophosphataemic HIV ‐positive adults on tenofovir
Author(s) -
Bech A,
Bentum P,
Nabbe K,
Gisolf J,
Richter C,
Boer H
Publication year - 2012
Publication title -
hiv medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.53
H-Index - 79
eISSN - 1468-1293
pISSN - 1464-2662
DOI - 10.1111/j.1468-1293.2012.01015.x
Subject(s) - fibroblast growth factor 23 , medicine , tenofovir , hypophosphatemia , parathyroid hormone , endocrinology , pathogenesis , renal function , phosphate , reabsorption , creatinine , fibroblast growth factor , hormone , human immunodeficiency virus (hiv) , calcium , kidney , biochemistry , receptor , immunology , chemistry
Objectives Hypophosphataemia is common in HIV ‐positive patients, in particular in those using tenofovir disoproxil fumarate ( TDF ). Its pathogenesis is not well understood. The importance of fibroblast growth factor 23 ( FGF ‐23), the most potent phosphaturic hormone known today, has not been studied in these patients. The aim of the study was to investigate whether FGF ‐23 might be involved in the aetiology of hypophosphataemia in HIV ‐positive patients on tenofovir. Methods Calcium and phosphate metabolism was studied in 36 HIV ‐positive patients on TDF . Hypophosphataemia was defined as a serum phosphate level < 0.75 mmol/L . Results Fifteen patients (42%) had hypophosphataemia (group 1), and 21 had a normal serum phosphate level (group 2). The renal phosphate reabsorption threshold [tubular maximum phosphate reabsorption per glomerular filtration rate (TmP/gfr)] was significantly lower in group 1 than in group 2 (0.58 ± 0.04 vs. 0.91 ± 0.03 mmol/L , respectively; P < 0.0001). The serum phosphate concentration was strongly correlated with TmP /gfr ( R = 0.71; P < 0.0001). Both groups had normal serum FGF ‐23 levels, and serum phosphate and TmP /gfr were not related to serum parathyroid hormone ( PTH ) or FGF ‐23 levels. Conclusion FGF ‐23 is not involved in the pathogenesis of hypophosphataemia in HIV ‐positive patients on TDF . The data suggest that a PTH ‐like factor may be involved.