AbstractAutologous platelet concentrates (APCs) applied alone or combined with other biomaterials are popular bioactive factors employed in regenerative medicine. The main biological rationale of using such products is to concentrate blood‐derived growth factors and cells into the wound microenvironment to enhance the body's natural healing capacity. First‐generation APC is represented by platelet‐rich plasma (PRP). While different protocols have been documented for PRP preparation, they overall consist of two cycles of centrifugation and have important limitations related to the use of an anticoagulant first and an activator afterward, which may interfere with the natural healing process and the release of bioactive molecules. The second generation of platelet concentrates is represented by leukocyte and platelet‐rich fibrin (L‐PRF). L‐PRF protocols involve a single centrifugation cycle and do not require the use of anticoagulants and activators, which makes the preparation more straight forward, less expensive, and eliminates potential risks associated with the use of activators. However, since no anticoagulant is employed, blood undergoes rapid clotting within the blood collection tube; hence, a timely management of L‐PRF is crucial. This review provides an overview on the most documented protocols for APC preparations and critically discusses the main differences between first‐ and second‐generation APCs in terms of cell content, protein release, and the formation of a 3D fibrin network. It appears evident that the inconsistency in reporting protocol parameters by most studies has contributed to conflicting conclusions regarding the efficacy of different APC formulations and has significantly limited the ability to interpret the results of individual clinical studies. In the future, the use of a standardized classification system, together with a detailed reporting on APC protocol parameters is warranted to make study outcomes comparable. This will also allow to clarify important aspects on the mechanism of action of APCs (like the role of leukocytes and centrifugation parameters) and to optimize the use of APCs in regenerative medicine.

中文翻译：

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第一代和第二代自体浓缩血小板的区别

摘要单独使用或与其他生物材料结合使用的自体血小板浓缩物（APC）是再生医学中常用的生物活性因子。使用此类产品的主要生物学原理是将血液来源的生长因子和细胞浓缩到伤口微环境中，以增强人体的自然愈合能力。第一代APC以富血小板血浆（PRP）为代表。虽然已记录了不同的 PRP 制备方案，但它们总体上由两个离心周期组成，并且具有与首先使用抗凝剂和随后使用激活剂相关的重要局限性，这可能会干扰自然愈合过程和生物活性分子的释放。第二代浓缩血小板以白细胞和富血小板纤维蛋白（L-PRF）为代表。L-PRF 方案涉及单个离心循环，不需要使用抗凝剂和活化剂，这使得制备过程更加直接、成本更低，并消除了与使用活化剂相关的潜在风险。然而，由于没有使用抗凝剂，血液在采血管内会快速凝固；因此，及时管理 L-PRF 至关重要。本综述概述了记录最多的 APC 制备方案，并批判性地讨论了第一代和第二代 APC 在细胞含量、蛋白质释放和 3D 纤维蛋白网络形成方面的主要差异。显然，大多数研究报告方案参数的不一致导致了关于不同 APC 制剂功效的相互矛盾的结论，并极大地限制了解释个别临床研究结果的能力。将来，需要使用标准化分类系统以及 APC 方案参数的详细报告，以使研究结果具有可比性。这也将有助于阐明 APC 作用机制的重要方面（如白细胞和离心参数的作用），并优化 APC 在再生医学中的使用。