纤维尺寸、耐久性/溶解性和生物持久性是纤维形成和致癌风险的关键因素。在现代，为了减少、改进和替代毒理学研究中的动物，体外测试方法的应用对于危害评估和设计安全使用的合成玻璃纤维 (SVF) 至关重要。本次审查的目的是：(1) 总结实施新方法 (NAM) 的国际框架和可接受性标准，(2) 评估不良结果路径 (AOP)、关键事件 (KE) 和关键事件关系（KER）根据经济合作与发展组织（OECD）指南进行纤维诱导的纤维形成和致癌作用，（3）考虑现有和新兴的呼吸系统计算机和体外毒性测试技术以及能力预测体内效果，(4) 概述评估新型 SVF 的危害和安全性的推荐测试策略，(5) 反思体外体内相关性 (IVIVC) 的方法需求和新 SVF 安全性评估的预测方法。遵循 OECD 概念模型的 AOP 框架是通过评估可用的分子和细胞起始事件而开发的，这些起始事件导致纤维诱导的纤维形成和癌变发展中的 KE 和 KER。 AOP 框架的开发包括考虑纤维的理化特性、呼吸沉积和清除模式、生物溶解度和生物持久性，以及细胞、器官和生物体反应。现有数据支持纤维 AOP 始于影响纤维暴露和生物溶解度的纤维理化特性，随后的关键引发事件取决于纤维的生物持久性和反应性。致病纤维的关键细胞事件包括氧化应激、慢性炎症以及上皮/成纤维细胞增殖和分化，最终导致增生、化生和纤维化/肿瘤形成。可用的体外模型（例如单细胞、多细胞、器官系统）提供了有前景的 NAM 工具来评估这些中间 KE。然而，SVF 的数据表明，体外生物溶解度是体内生物持久性和生物效应下游事件的合理预测因子。体外 SVF 纤维溶解速率 >100ng/cm2/hr（pH 7 中的玻璃纤维和 pH 4.5 中的石纤维）和体内 SVF 纤维清除半衰期小于 40 或 50 天，与动物的纤维化或肿瘤无关。超过这些纤维溶解和清除阈值的长（纤维长度> 20μm）生物耐久性和生物持久性纤维可能会带来纤维化和癌症的风险。体外纤维溶解测定为预测体内 SVF 纤维的生物持久性、危害和健康风险提供了一种有前途的途径和潜在的强大工具。用于纤维（包括 SVF）的 NAM 可能涉及多因素体外方法，利用体外溶出数据与基于细胞和组织的体外测定相补充来预测健康风险。

Fiber dimension, durability/dissolution, and biopersistence are critical factors for the risk of fibrogenesis and carcinogenesis. In the modern era, to reduce, refine, and replace animals in toxicology research, the application of in vitro test methods is paramount for hazard evaluation and designing synthetic vitreous fibers (SVFs) for safe use. The objectives of this review are to: (1) summarize the international frameworks and acceptability criteria for implementation of new approach methods (NAMs), (2) evaluate the adverse outcome pathways (AOPs), key events (KEs), and key event relationships (KERs) for fiber-induced fibrogenesis and carcinogenesis in accordance with Organization for Economic Co-operation and Development (OECD) guidelines, (3) consider existing and emerging technologies for in silico and in vitro toxicity testing for the respiratory system and the ability to predict effects in vivo, (4) outline a recommended testing strategy for evaluating the hazard and safety of novel SVFs, and (5) reflect on methods needs for in vitro in vivo correlation (IVIVC) and predictive approaches for safety assessment of new SVFs. AOP frameworks following the conceptual model of the OECD were developed through an evaluation of available molecular and cellular initiating events, which lead to KEs and KERs in the development of fiber-induced fibrogenesis and carcinogenesis. AOP framework development included consideration of fiber physicochemical properties, respiratory deposition and clearance patterns, biosolubility, and biopersistence, as well as cellular, organ, and organism responses. Available data support that fiber AOPs begin with fiber physicochemical characteristics which influence fiber exposure and biosolubility and subsequent key initiating events are dependent on fiber biopersistence and reactivity. Key cellular events of pathogenic fibers include oxidative stress, chronic inflammation, and epithelial/fibroblast proliferation and differentiation, which ultimately lead to hyperplasia, metaplasia, and fibrosis/tumor formation. Available in vitro models (e.g. single-, multi-cellular, organ system) provide promising NAMs tools to evaluate these intermediate KEs. However, data on SVFs demonstrate that in vitro biosolubility is a reasonable predictor for downstream events of in vivo biopersistence and biological effects. In vitro SVF fiber dissolution rates >100 ng/cm2/hr (glass fibers in pH 7 and stone fibers in pH 4.5) and in vivo SVF fiber clearance half-life less than 40 or 50 days were not associated with fibrosis or tumors in animals. Long (fiber lengths >20 µm) biodurable and biopersistent fibers exceeding these fiber dissolution and clearance thresholds may pose a risk of fibrosis and cancer. In vitro fiber dissolution assays provide a promising avenue and potentially powerful tool to predict in vivo SVF fiber biopersistence, hazard, and health risk. NAMs for fibers (including SVFs) may involve a multi-factor in vitro approach leveraging in vitro dissolution data in complement with cellular- and tissue- based in vitro assays to predict health risk.