In osteoporotic women treated with strontium ranelate, strontium is located in bone formed during treatment with a maintained degree of mineralization.
In postmenopausal osteoporotic women and up to 3 years of treatment with strontium ranelate, strontium was present only in recently deposited bone tissue resulting from formation activity during the period of treatment. Strontium was shown to be dose-dependently deposited into this newly formed bone with preservation of the mineralization.


BACKGROUND
Interactions between strontium (Sr) and bone mineral and its effects on mineralization were investigated in women treated with strontium ranelate.


METHODS
Bone biopsies from osteoporotic women were obtained over 5-year strontium ranelate treatment from phases II and III studies. Bone samples obtained over 3-year treatment were investigated by X-ray microanalysis for bone Sr uptake and focal distribution, and by quantitative microradiography for degree of mineralization. On some samples, Sr distribution (X-ray cartography) was analyzed on whole sample surfaces and the percentage of bone surface containing Sr was calculated. Bone Sr content was chemically measured on whole samples.


RESULTS
In treated women, Sr was exclusively present in bone formed during treatment; Sr deposition depended on the dose with higher focal content in new bone structural units than in old ones constantly devoid of Sr, even after 3-year treatment. A plateau in global bone Sr content was reached after 3 years of treatment. Cartography illustrated the extent of surfaces containing Sr, and formation activity during strontium ranelate treatment was higher in cancellous than in cortical bone. Mineralization was maintained during treatment.


CONCLUSIONS
The quality of bone mineral was preserved after treatment with strontium ranelate, supporting the safety of this agent at the bone tissue level.
Boivin
G
G
INSERM Unité 831, Faculté de Médecine R. Laennec, Université de Lyon, Lyon, France. Georges.Boivin@sante.univ-lyon1.fr
Farlay
D
D
Khebbab
M T
MT
Jaurand
X
X
Delmas
P D
PD
Meunier
P J
PJ
D000368:Aged; D001706:Biopsy; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000493:pharmacokinetics* / Q000627:therapeutic use; D001842:Bone and Bones / Q000378:metabolism; D002113:Calcification, Physiologic / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004577:Electron Probe Microanalysis / Q000379:methods; D005260:Female; D006801:Humans; D007085:Ilium / Q000378:metabolism / Q000473:pathology; D008852:Microradiography / Q000379:methods; D008875:Middle Aged; D009942:Organometallic Compounds / Q000493:pharmacokinetics* / Q000627:therapeutic use; D015663:Osteoporosis, Postmenopausal / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D013876:Thiophenes / Q000493:pharmacokinetics* / Q000627:therapeutic use
D050071:Bone Density Conservation Agents; D009942:Organometallic Compounds; D013876:Thiophenes; C081587:strontium ranelate