Acquired resistance to pamidronate treated effectively with zoledronate in juvenile Paget's disease

Juvenile Paget's Disease: Report of a successful treatment throughout the complete growth of a patient with a missense TNFRSF11B mutation

INTRODUCTION

Juvenile Paget's Disease (JPD) is an ultra-rare inherited osteopathy featuring markedly accelerated bone turnover. Several clinical characteristics have been reported, including bone deformities developing in childhood and hearing loss.

CASE REPORT

We report the case of a 2 ¾-year-old girl that presented with progressive bowing of both legs since the age of 2, lower limb pain and frequent falls with one consequent femur fracture. Plain radiographs revealed osteoectasia of the long bone's diaphysis, and laboratory tests showed extremely high serum total alkaline phosphatase levels. A missense mutation on the gene TNFRSF11B was identified in homozygosity, and the diagnosis of JPD was made. Treatment with bisphosphonates was initiated early and markedly improved lower limb bowing and pain. The patient reached adulthood with normal height, minor bone deformities, and no functional impairment. Despite the good skeletal symptom's response, bisphosphonates failed to prevent or improve sensorineural hearing loss.

CONCLUSIONS

In this clinical case, early treatment with bisphosphonates was effective for the treatment of JPD skeletal deformities. New therapeutic strategies need to be developed to better control the extraskeletal manifestations of JPD.

Ultra-Small Lysozyme-Protected Gold Nanoclusters as Nanomedicines Inducing Osteogenic Differentiation

PURPOSE

Ultra-small gold nanoclusters (AuNCs), as emerging fluorescent nanomaterials with excellent biocompatibility, have been widely investigated for in vivo biomedical applications. However, their effects in guiding osteogenic differentiation have not been investigated, which are important for osteoporosis therapy and bone regeneration. Herein, for the first time, lysozyme-protected AuNCs (Lys-AuNCs) are used to stimulate osteogenic differentiation, which have the potential for the treatment of bone disease.

METHODS

Proliferation of MC3T3E-1 is important for osteogenic differentiation. First, the proliferation rate of MC3T3E-1 was studied by Cell Counting Kit-8 (CCK8) assays. Signaling pathways of PI3K/Akt play central roles in controlling proliferation throughout the body. The expression of PI3K/Akt was investigated in the presence of lysozyme, and lysozyme-protected AuNCs (Lys-AuNCs) by Western blot (WB) and intracellular cell imaging to evacuate the osteogenic differentiation mechanisms. Moreover, the formation of osteoclasts (OC) plays a negative role in the differentiation of osteoblasts. Nuclear factor κB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF) signaling pathways are used to understand the negative influence of the osteogenic differentiation by the investigation of Raw 264.7 cell line. Raw 264.7 (murine macrophage-like) cells and NIH/3T3 (mouse fibroblast) cells were treated with tyloxapol, and the cell viability was assessed. Raw 264.7 cells have also been used for in vitro studies, on understanding the osteoclast formation and function. The induced osteoclasts were identified by TRAP confocal fluorescence imaging. These key factors in osteoclast formation, such as (NFATc-1, c-Fos, V-ATPase-2 and CTSK), were investigated by Western blot.

RESULTS

Based on the above investigation, Lys-AuNCs were found to promote osteogenic differentiation and decrease osteoclast activity. It is noteworthy that the lysozyme (protected template), AuNPs, or the mixture of Lysozyme and AuNPs have negligible effects on osteoblastic differentiation compared to Lys-AuNCs.

CONCLUSION

This study opens up a novel avenue to develop a new gold nanomaterial for promoting osteogenic differentiation. The possibility of using AuNCs as nanomedicines for the treatment of osteoporosis can be expected.