Strontium ranelate inhibits wear particle-induced aseptic loosening in mice

The imbalance between bone formation and osteolysis plays a key role in the pathogenesis of aseptic loosening. Strontium ranelate (SR) can promote bone formation and inhibit osteolysis. The aim of this study was to explore the role and mechanism of SR in aseptic loosening induced by wear particles. Twenty wild-type (WT) female C57BL/6j mice and 20 sclerostin-/- female C57BL/6j mice were used in this study. Mice were randomly divided into four groups: WT control group, WT SR group, knockout (KO) control group, and KO SR group. We found that SR enhanced the secretion of osteocalcin (0.72±0.007 in WT control group, 0.98±0.010 in WT SR group, P=0.000), Runx2 (0.34±0.005 in WT control group, 0.47±0.010 in WT SR group, P=0.000), β-catenin (1.04±0.05 in WT control group, 1.22±0.02 in WT SR group, P=0.000), and osteoprotegerin (OPG) (0.59±0.03 in WT control group, 0.90±0.02 in WT SR group, P=0.000). SR significantly decreased the level of receptor activator for nuclear factor-κB ligand (RANKL) (1.78±0.08 in WT control group, 1.37±0.06 in WT SR group, P=0.000) and improved the protein ratio of OPG/RANKL, but these effects were not observed in sclerostin-/- mice. Our findings demonstrated that SR enhanced bone formation and inhibited bone resorption in a wear particle-mediated osteolysis model in wild-type mice, and this effect relied mainly on the down-regulation of sclerostin levels to ameliorate the inhibition of the canonical Wnt pathway.

Lesión osteolítica de calota por sífilis secundaria / Injury by skull osteolytic secundary syphilis

Bone involvement of syphilis can be observed in tertiary and congenital syphilis. It is infrequent during the secondary stage. The skull is the most affected bone in secondary syphilis, and its most frequent form of presentation is proliferative osteitis. If the skull is affected, headache is usual and can be as intense as in meningitis. Osteolyitic lesions may be seen in complimentary imaging studies, with a moth eaten aspect. These lesions raise concern over a number of differential diagnoses, among which are infectious, inflammatory and neoplastic diseases. The definitive diagnosis is made by bone biopsy of the compromised bone. Molecular techniques in the affected tissues increases diagnostic performance. There is no standardized treatment protocol for syphilis since there are no guidelines available. We report a case of a 19 year old female, presenting with a unique osteolytic lesion in the skull due to secondary syphilis.

El compromiso óseo de la sífilis se observa predominantemente en la sífilis terciaria y en la sífilis congénita, siendo infrecuente durante el estadio secundario. El hueso más afectado durante la sífilis secundaria es el cráneo, siendo la osteítis proliferativa la forma más frecuente de presentación. Cuando afecta la calota, la cefalea es habitual y puede ser tan intensa que se confunde con un proceso meníngeo. En las imágenes se observan lesiones líticas de aspecto apolillado, planteando el diagnóstico diferencial con otras patologías infecciosas, inflamatorias y neoplásicas. El diagnóstico definitivo se realiza por estudio histológico del hueso comprometido. Las técnicas de biología molecular en los tejidos afectados aumentan el rendimiento diagnóstico. No existen protocolos estandarizados para el tratamiento de la sífilis con compromiso óseo. Presentamos el caso clínico de una mujer de 19 años de edad, con una lesión osteolítica única de calota debida a una sífilis secundaria.