Evans Holly, Andrews Rebecca, Abedi Fatma Ali, Sprules Alexandria, Trend Jacob, Lovric Goran, Green Alanna, Chantry Andrew, Clarkin Claire, Brown Janet, Lawson Michelle
Division of Clinical Medicine and Mellanby Centre for Musculoskeletal Research, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield S10 2RX, United Kingdom.
Department of Haematology, Sheffield Teaching Hospitals, Royal Hallamshire Hospital NHS Foundation Trust, Sheffield S10 2JF, United Kingdom.
JBMR Plus. 2024 Jul 12;8(9):ziae093. doi: 10.1093/jbmrpl/ziae093. eCollection 2024 Sep.
Myeloma bone disease (MBD) affects ~90% of multiple myeloma patients, but current treatment options are suboptimal. Therefore, to successfully develop new therapies or optimize current ones, we must improve our fundamental knowledge of how myeloma affects bone microstructure and function. Here, we have investigated the osteocyte lacuno-canalicular network (LCN) in MBD, as bone porosity affects bone quality and resilience. We used the syngeneic 5TGM1-C57BL-Kalwrij and the xenograft U266-NSG models at end stage and compared them to healthy controls (naïve). Micro-computed tomography (μCT) and histomorphometry indicated the 5TGM1 and U266 models developed mild and extensive MBD, respectively, with the U266 model producing large osteolytic lesions. High-resolution synchrotron micro-CT (SR-μCT) revealed significant osteocyte lacunae changes in U266 bones but not 5TGM1, with a reduction in lacunae number and sphericity, and an increase in lacunae volume compared with naïve. Canalicular length, visualized using histological Ploton silver staining, appeared significantly shorter in 5TGM1 and U266 bones compared with naïve. Canalicular area as a proportion of the bone was also decreased by 24.2% in the U266 model. We observed significant upregulation of genes implicated in peri-lacunar remodeling (PLR), but immunohistochemistry confirmed that the osteocyte-specific protein sclerostin, a known driver of PLR, was unchanged between MBD and naïve bones. In summary, we have demonstrated evidence of PLR and altered organization of the osteocyte LCN in MBD mouse models. The next step would be to further understand the drivers and implications of PLR in MBD, and whether treatments to manipulate PLR and the LCN may improve patient outcomes.
骨髓瘤骨病(MBD)影响约90%的多发性骨髓瘤患者,但目前的治疗方案并不理想。因此,为了成功开发新疗法或优化现有疗法,我们必须加深对骨髓瘤如何影响骨微结构和功能的基础知识的了解。在此,我们研究了MBD中的骨细胞陷窝-小管网络(LCN),因为骨孔隙率会影响骨质量和弹性。我们在终末期使用了同基因的5TGM1-C57BL-Kalwrij模型和异种移植U266-NSG模型,并将它们与健康对照(未处理)进行比较。微计算机断层扫描(μCT)和组织形态计量学表明,5TGM1和U266模型分别出现了轻度和广泛的MBD,U266模型产生了大的溶骨性病变。高分辨率同步加速器微CT(SR-μCT)显示,U266骨中的骨细胞陷窝有显著变化,而5TGM1骨中没有,与未处理相比,陷窝数量和球形度减少,陷窝体积增加。使用组织学Ploton银染法观察到的小管长度,与未处理相比,5TGM1和U266骨中的小管长度明显更短。U266模型中,小管面积占骨面积的比例也降低了24.2%。我们观察到与陷窝周围重塑(PLR)相关的基因显著上调,但免疫组织化学证实,骨细胞特异性蛋白硬化蛋白(一种已知的PLR驱动因子)在MBD骨和未处理骨之间没有变化。总之,我们已经在MBD小鼠模型中证明了PLR和骨细胞LCN组织改变的证据。下一步将是进一步了解PLR在MBD中的驱动因素和影响,以及操纵PLR和LCN的治疗方法是否可以改善患者的预后。