Table 1:
Biochemical values and trabecular bone histomorphometric indices of turnover, mineralization, and volume in a cross-section of 56 dialysis patients, not receiving active vitamin D sterol therapy, whose bone biopsy samples were evaluated for FGF23 staining.
| Normal numbers of FGF23-expressing osteocytes (n=28) | Increased numbers of FGF23-expressing osteocytes (n=28) | Normal Range* | |
|---|---|---|---|
| Demographic Data | |||
| Age (years) | 15.8 ± 0.8 | 15.8 ± 1.0 | NA |
| Gender (M/F) | 22/6 | 20/8 | NA |
| Cause of kidney disease (n) (CAKUT/glomerular disease/unknown) | 7/13/8 | 10/11/7 | NA |
| Biochemical Values | |||
| Calcium (mg/dl) | 9.0 ± 0.2 | 8.9 ± 0.3 | 8.4 – 10.2 |
| Phosphorus (mg/dl) | 5.7 ± 0.3 | 6.1 ± 0.3 | (age specific) |
| PTH¥ (pg/ml) | 457 (238, 873) | 407 (123, 741) | 10 – 65 |
| FGF23¥¥ (RU/ml) | 1147 (705, 1989) | 1989 (476, 9351)** | <100 |
| Trabecular Bone Turnover | |||
| Bone formation rate (BFR/BS) (μm3/mm2/yr) | 47.7 (30.0, 67.7) | 42.0 (10.4, 75.2) | 8.0 – 73.4 |
| Trabecular Bone Mineralization | |||
| Osteoid surface (OS/BS) (%) | 40.0 ± 2.6 | 33.6 ± 3.0 | 4.3 – 31.7 |
| Osteoid volume (OV/BV) (%) | 8.8 ± 2.3 | 5.2 ± 0.7 | 0.2 – 5.8 |
| Osteoid thickness (O.Th) (μm) | 12.2 ± 0.7 | 9.1 ± 0.6** | 2.0 – 13.2 |
| Osteoid maturation time (OMT) (d) | 13.7 (11.5, 19.9) | 9.1 (7.7, 16.5) | 1.2 – 11.5 |
| Mineralization lag time (MLT) (d) | 28.5 (20.9, 104.7) | 28.6 (16.3, 54.9) | 2.3 – 63.8 |
| Trabecular Bone Volume | |||
| Bone volume (BV/TV) (%) | 35.1 ± 2.1 | 30.4 ± 1.3 | 8.9 – 34.4 |
normal range for bone histomorphometric variables from n=31 healthy controls as previously reported (Bakkaloglu SA 2010 Clin J Am Soc Nephrol 5:1860–1866)
NA: not applicable
p<0.05 between groups
PTH: 1st generation immunometric assay (Quidel Corporation, San Diego, California), which detects full-length PTH as well as large C-terminal fragments (normal range: 10–65 pg/ml)
C-terminal FGF23: 2nd generation C-terminal FGF23 assay (Quidel), which detects both the full-length and C-terminal portions of the molecule in circulation