开发可靠的疾病活动生物标志物对于诊断、预后和新药开发至关重要。尽管计算机断层扫描 (CT) 是量化骨侵蚀的黄金标准，但对于复杂关节侵蚀性关节炎的具体结果测量的利用，还没有达成共识的方法或理由。对于临床前模型，例如性别二态性肿瘤坏死因子转基因（TNF-Tg）小鼠，通常通过手动分割距骨或相邻骨骼的小区域来量化踝关节的疾病严重程度，主要是因为测量方便。在此，我们试图确定代表性别依赖性疾病进展的可靠生物标志物的特定后爪骨，以指导未来的调查和分析。对野生型（n = 4 男性，n = 4 女性）和 TNF 进行后爪微型 CT -Tg（n = 4 只雄性，n = 7 只雌性）小鼠，每月间隔 2-5 个月（雌性）和 2-8 个月（雄性），因为雌性 TNF-Tg 小鼠表现出心肺疾病的早期死亡率约为5-6 个月。此外，8 个月大的 WT (n = 4) 和 TNF-Tg 雄性接受抗 TNF 单克隆抗体 (n = 5) 或 IgG 安慰剂同种型对照 (n = 6) 治疗 6 周，并使用 micro-CT 进行成像每 3 周一次。对于图像分析，我们在 Amira 软件中利用了最近开发的高通量和半自动分割策略。使用 Visiopharm 对踝关节的滑膜和破骨细胞组织学进行量化。首先，我们证明了自动分割的准确性（通过单个用户对约 9000 个个体骨骼的分析确定）在校正前的野生型和 TNF-Tg 后爪中具有可比性（ 79.2±8.9% 与 80.1±5.1%，p = 0.52）。与其他骨区相比，雌性 TNF-Tg 小鼠的跗骨区域表现出突然、特异且显着的骨量减少，但雄性小鼠则没有，5 个月时（4 个月 4.3± 0.22 与 5 个月 3.4± 0.62 mm3，p<0.05）。具体来说，与其他跗骨相比，长方体在早期时间点显示出明显减少的骨量（即 4 个月：长方体 -24.1±7.2% 与距骨 -9.0±5.9% 的 2 个月基线）。位于脚踝前外侧区域的其他骨骼在女性跗骨区域也表现出严重的侵蚀，与滑膜炎和破骨细胞的增加相一致。在患有严重关节炎的 TNF-Tg 雄性小鼠中，距骨和跟骨对抗 TNF 治疗表现出最敏感的反应，通过治疗期间骨体积变化的效应大小来测量。我们证明了 TNF-Tg 小鼠关节炎后爪的性别二态性变化具有骨骼特异性，其中长方体可作为雌性小鼠糜烂性关节炎的可靠早期生物标志物。在临床前或临床模型中采用自动分割方法有可能转化定量生物标志物，以监测疾病中的骨侵蚀并评估治疗效果。版权所有：© 2024 Kenney 等人。这是一篇根据知识共享署名许可条款分发的开放获取文章，允许在任何媒体上不受限制地使用、分发和复制，前提是注明原始作者和来源。

Development of reliable disease activity biomarkers is critical for diagnostics, prognostics, and novel drug development. Although computed tomography (CT) is the gold-standard for quantification of bone erosions, there are no consensus approaches or rationales for utilization of specific outcome measures of erosive arthritis in complex joints. In the case of preclinical models, such as sexually dimorphic tumor necrosis factor transgenic (TNF-Tg) mice, disease severity is routinely quantified in the ankle through manual segmentation of the talus or small regions of adjacent bones primarily due to the ease in measurement. Herein, we sought to determine the particular hindpaw bones that represent reliable biomarkers of sex-dependent disease progression to guide future investigation and analysis.Hindpaw micro-CT was performed on wild-type (n = 4 male, n = 4 female) and TNF-Tg (n = 4 male, n = 7 female) mice at monthly intervals from 2-5 (females) and 2-8-months (males) of age, since female TNF-Tg mice exhibit early mortality from cardiopulmonary disease at approximately 5-6-months. Further, 8-month-old WT (n = 4) and TNF-Tg males treated with anti-TNF monoclonal antibodies (n = 5) or IgG placebo isotype controls (n = 6) for 6-weeks were imaged with micro-CT every 3-weeks. For image analysis, we utilized our recently developed high-throughput and semi-automated segmentation strategy in Amira software. Synovial and osteoclast histology of ankle joints was quantified using Visiopharm.First, we demonstrated that the accuracy of automated segmentation, determined through analysis of ~9000 individual bones by a single user, was comparable in wild-type and TNF-Tg hindpaws before correction (79.2±8.9% vs 80.1±5.1%, p = 0.52). Compared to other bone compartments, the tarsal region demonstrated a sudden, specific, and significant bone volume reduction in female TNF-Tg mice, but not in males, by 5-months (4-months 4.3± 0.22 vs 5-months 3.4± 0.62 mm3, p<0.05). Specifically, the cuboid showed significantly reduced bone volumes at early timepoints compared to other tarsals (i.e., 4-months: Cuboid -24.1±7.2% vs Talus -9.0±5.9% of 2-month baseline). Additional bones localized to the anterolateral region of the ankle also exhibited dramatic erosions in the tarsal region of females, coinciding with increased synovitis and osteoclasts. In TNF-Tg male mice with severe arthritis, the talus and calcaneus exhibited the most sensitive response to anti-TNF therapy measured by effect size of bone volume change over treatment period.We demonstrated that sexually dimorphic changes in arthritic hindpaws of TNF-Tg mice are bone-specific, where the cuboid serves as a reliable early biomarker of erosive arthritis in female mice. Adoption of automated segmentation approaches in pre-clinical or clinical models has potential to translate quantitative biomarkers to monitor bone erosions in disease and evaluate therapeutic efficacy.Copyright: © 2024 Kenney et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.