Bone material quality in transiliac bone biopsies of postmenopausal osteoporotic women after 3 years of strontium ranelate treatment.
Strontium ranelate (SrR) is a relatively new treatment for osteoporosis. In this study we investigated its potential impact on human bone material quality in transiliac bone biopsies from postmenopausal osteoporotic women treated 3 years with calcium and vitamin D plus either 2 g SrR per day or placebo. Bone mineralization density distribution (BMDD), strontium (Sr) concentration, collagen cross-link ratio, and indentation modulus were analyzed by quantitative backscattered electron imaging, electron-induced X-ray fluorescence analysis, synchrotron radiation induced micro X-ray fluorescence elemental mapping, Fourier transform infrared imaging, and nanoindentation, respectively. The BMDD of SrR-treated patients was shifted to higher atomic numbers (Z(mean) +1.5%, p < .05 versus placebo). We observed Sr being preferentially incorporated in bone packets formed during SrR treatment up to 6% atom fraction [Sr/(Sr + Ca)] depending on the SrR serum levels of the individuals (correlation r = 0.84, p = .018). Collagen cross-link ratio was preserved in SR-treated bone. The indentation modulus was significantly decreased in younger versus older bone packets for both placebo- (-20.5%, p < .0001) and SrR-treated individuals (-24.3%, p < .001), whereas no differences were found between the treatment groups. In conclusion, our findings indicate that after SrR treatment, Sr is heterogeneously distributed in bone and preferentially present in bone packets formed during treatment. The effect of SrR on BMDD seems to be due mainly to the uptake of Sr and not to changes in bone calcium content. Taken together, these data provide evidence that the investigated bone quality determinants at tissue level were preserved in postmenopausal osteoporotic women after 3-year treatment with 2 g SrR per day plus calcium and vitamin D.
Roschger
Paul
P
Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 4th Medical Department, Hanusch Hospital, 1140 Vienna, Austria. paul.roschger@osteologie.at
Manjubala
Inderchand
I
Zoeger
Norbert
N
Meirer
Florian
F
Simon
Rolf
R
Li
Chenghao
C
Fratzl-Zelman
Nadja
N
Misof
Barbara M
BM
Paschalis
Eleftherios P
EP
Streli
Christina
C
Fratzl
Peter
P
Klaushofer
Klaus
K
D015519:Bone Density / Q000187:drug effects*; D050071:Bone Density Conservation Agents / Q000627:therapeutic use*; D002118:Calcium / Q000627:therapeutic use; D003094:Collagen / Q000737:chemistry; D055119:Elastic Modulus; D005260:Female; D006801:Humans; D007085:Ilium / Q000737:chemistry / Q000473:pathology*; D009942:Organometallic Compounds / Q000032:analysis / Q000627:therapeutic use*; D015663:Osteoporosis, Postmenopausal / Q000188:drug therapy* / Q000473:pathology; D013876:Thiophenes / Q000032:analysis / Q000627:therapeutic use*; D014807:Vitamin D / Q000627:therapeutic use
D050071:Bone Density Conservation Agents; D009942:Organometallic Compounds; D013876:Thiophenes; C081587:strontium ranelate; D014807:Vitamin D; D003094:Collagen; D002118:Calcium