Aims: Renal osteodystrophy occurs in the early stages of chronic kidney disease (CKD) and progresses during loss of kidney function. Fibroblast growth factor (FGF)-23 and sclerostin, both produced by osteocytes, are increased in blood of patients with CKD. The aim of this study was to analyze the impact of decline in kidney function on FGF-23 and sclerostin protein expression in bone and to study their relationship with their serum levels and bone histomorphometry. Materials and methods: 108 patients aged 25 - 81 years (mean ± SD: 56 ± 13 years) underwent anterior iliac crest biopsies after double-tetracycline labeling. Eleven patients were CKD-2, 16 were CKD-3, 9 were CKD-4 - 5, and 64 CKD-5D. Patients were on hemodialysis for 49 ± 117 months. 18 age-matched patients without CKD were included as controls. Immunostaining was performed on undecalcified bone sections to quantify FGF-23 and sclerostin expression. Bone sections were also evaluated by histomorphometry for bone turnover, mineralization, and volume. Results: FGF-23 expression in bone correlated positively with CKD stages (p < 0.001) increasing from 5.3-to 7.1-fold starting at CKD-2. No difference in FGF-23 expression was seen between trabecular and cortical bone. Sclerostin expression in bone correlated positively with CKD stages (p < 0.001) with an increase from 3.8-to 5.1-fold starting at CKD-2. This increase was progressive and significantly greater in cortical than cancellous bone. FGF-23 and sclerostin in blood and bone were strongly associated with bone turnover parameters. Expression of FGF-23 in cortical bone correlated positively with activation frequency (Ac.f) and bone formation rate (BFR/BS) (p < 0.05), while sclerostin correlated negatively with Ac.f, BFR/BS, and osteoblast and osteoclast numbers (p < 0.05). FGF-23 trabecular and cortical expressions correlated positively with cortical thickness (p < 0.001). Sclerostin bone expression correlated negatively with parameters of trabecular thickness and osteoid surface (p < 0.05). Conclusion: These data show a progressive increase in FGF-23 and sclerostin in blood and bone associated with decrease in kidney function. The observed relationships between bone turnover and sclerostin or FGF-23 should be considered when treatment modalities are developed for management of turnover abnormalities in CKD patients.
|Number of pages||10|
|State||Published - May 2023|
Bibliographical noteFunding Information:
Research reported in this publication was supported by National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health Award R01080770 and the Kentucky Nephrology Research Trust. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
© 2023 Dustri-Verlag Dr. K. Feistle.
- bone histomorphometry
- renal osteodystrophy
ASJC Scopus subject areas