[Effect of strontium on bone metabolism in hemodialysis patients]

The objective of this study was to assess the relationship between the bone strontium content and bone histomorphometric parameters in bone biopsies from patients with chronic renal failure undergoing hemodialysis. The study was carried out in 74 illiac crest bone biopsies from patients with renal osteodystrophy from different worldwide regions (Argentina, Portugal and Spain). They were underwent to histological and histomorphometric evaluation. The bone strontium/calcium ratio was measured by quadrupole inductively coupled plasma-mass spectrometry. The samples were classified into groups according to histological criteria: hyperparathyroidism (HP), mixed (MX), osteomalacia (OM) and adynamic bone disease (ABD). Serum PTH and alkaline phosphatase before biopsy were available in most of the patients. No correlation was found between the different histomorphometric parameters and the Sr/Ca ratio. The one way ANOVA test showed statistical differences in the Sr/Ca ratio of the different histological forms (HP: 0.58 +/- 0.39; MX: 1.16 +/- 0.74; OM: 1.10 +/- 0.46; ABD: 0.91 +/- 0.40 microgram Sr/mg Ca; p < 0.003). The post-Hoc analysis showed differences between HP and MX. The biopsies having greater or equal values than 1.4 micrograms Sr/mg Ca showed higher levels of bone formation histomorphometric parameters and serum alkaline phosphatase (395 +/- 519 vs 1,022 +/- 989 UI/L, p < 0.05). Although it has been found that the biopsies with higher bone strontium had higher levels of osteoid tissue (characteristic of osteomalacia), the hypothesis of strontium-induced osteomalacia could not be demonstrated.