Primary osteoblast-like cells from patients with end-stage kidney disease reflect gene expression, proliferation, and mineralization characteristics ex vivo

Kidney Int. 2015 Mar;87(3):593-601. doi: 10.1038/ki.2014.347. Epub 2014 Oct 29.

Abstract

Osteocytes regulate bone turnover and mineralization in chronic kidney disease. As osteocytes are derived from osteoblasts, alterations in osteoblast function may regulate osteoblast maturation, osteocytic transition, bone turnover, and skeletal mineralization. Thus, primary osteoblast-like cells were cultured from bone chips obtained from 24 pediatric ESKD patients. RNA expression in cultured cells was compared with RNA expression in cells from healthy individuals, to RNA expression in the bone core itself, and to parameters of bone histomorphometry. Proliferation and mineralization rates of patient cells were compared with rates in healthy control cells. Associations were observed between bone osteoid accumulation, as assessed by bone histomorphometry, and bone core RNA expression of osterix, matrix gla protein, parathyroid hormone receptor 1, and RANKL. Gene expression of osteoblast markers was increased in cells from ESKD patients and signaling genes including Cyp24A1, Cyp27B1, VDR, and NHERF1 correlated between cells and bone cores. Cells from patients with high turnover renal osteodystrophy proliferated more rapidly and mineralized more slowly than did cells from healthy controls. Thus, primary osteoblasts obtained from patients with ESKD retain changes in gene expression ex vivo that are also observed in bone core specimens. Evaluation of these cells in vitro may provide further insights into the abnormal bone biology that persists, despite current therapies, in patients with ESKD.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 25-Hydroxyvitamin D3 1-alpha-Hydroxylase / genetics
  • Adolescent
  • Bone and Bones / pathology
  • Bone and Bones / physiopathology*
  • Calcification, Physiologic*
  • Calcium-Binding Proteins / genetics
  • Cell Proliferation*
  • Cells, Cultured
  • Chronic Kidney Disease-Mineral and Bone Disorder / genetics
  • Extracellular Matrix Proteins / genetics
  • Female
  • Gene Expression*
  • Humans
  • Kidney Failure, Chronic* / genetics
  • Kidney Failure, Chronic* / pathology
  • Male
  • Matrix Gla Protein
  • Osteoblasts / pathology
  • Osteoblasts / physiology*
  • Phosphoproteins / genetics
  • RANK Ligand / genetics
  • RNA / metabolism
  • Receptor, Parathyroid Hormone, Type 1 / genetics
  • Receptors, Calcitriol / genetics
  • Signal Transduction / genetics
  • Sodium-Hydrogen Exchangers / genetics
  • Sp7 Transcription Factor
  • Transcription Factors / genetics
  • Vitamin D3 24-Hydroxylase / genetics

Substances

  • Calcium-Binding Proteins
  • Extracellular Matrix Proteins
  • Phosphoproteins
  • RANK Ligand
  • Receptor, Parathyroid Hormone, Type 1
  • Receptors, Calcitriol
  • Sodium-Hydrogen Exchangers
  • Sp7 Transcription Factor
  • SP7 protein, human
  • TNFSF11 protein, human
  • Transcription Factors
  • VDR protein, human
  • sodium-hydrogen exchanger regulatory factor
  • RNA
  • CYP24A1 protein, human
  • Vitamin D3 24-Hydroxylase
  • 25-Hydroxyvitamin D3 1-alpha-Hydroxylase
  • CYP27B1 protein, human