Once thought to have revolutionized therapeutic intervention in surgery, Recombinant Human Bone Morphogenic Protein 2 (rhBMP2) is now in its second decade of sustained controversy over the side effects associated with its use. Side effects associated with clinical use of rhBMP2 (Infuse, Medtronic Inc) include a marked inflammatory response, pain, therapeutic failures, ectopic bone, tissue degradation, and death. What is missing, despite the depth of literature on the subject, is a direct interrogation of rhBMP2, specifically for inflammation. Here we set out to determine if rhBMP2 alters traditional macrophage markers associated with pro-inflammatory responses, and pro-reparative responses to injury. Based on our previous work, we hypothesized there would be no direct effect of the peptide on macrophage polarization. Here we utilized commercially available murine macrophages, RAW 264.7, and treated these cells with rhBMP2 in standard growth media or macrophage polarizing media (M1 and M2) at several doses of the peptide. Our readouts were cell viability, apoptosis, gene expression of M1 and M2 markers, and ELISA for M1 marker iNOS, and M2 marker Arg1. Our data give very little evidence to support an alteration in macrophage phenotype by rhBMP2 alone, or alteration of the phenotype when cultured in enriched M1 or M2 media. These results further suggest that other factors associated with the clinical use of Infuse, likely supraphysiological rhBMP2 doses and off label usage, are more likely the culprit for poor outcomes. This further reinforces the utility of rhBMP2 and other peptides in tissue engineering therapies when conditions are tightly controlled.

中文翻译：

---

单独的rhBMP2不会诱导巨噬细胞极化，导致炎症反应增加。

重组人骨形态发生蛋白2（rhBMP2）曾经被认为已彻底改变了外科手术的治疗手段，现在正处于与其使用相关的副作用持续争议的第二个十年。与rhBMP2的临床使用相关的副作用（输液，美敦力公司）包括明显的炎症反应，疼痛，治疗失败，异位骨，组织降解和死亡。尽管有关该主题的文献很多，但缺少的是对rhBMP2的直接询问，特别是针对炎症的询问。在这里，我们着手确定rhBMP2是否会改变与促炎反应以及对损伤的亲修复反应相关的传统巨噬细胞标志物。根据我们以前的工作，我们假设该肽不会对巨噬细胞极化产生直接影响。在这里，我们利用市售的鼠巨噬细胞RAW 264.7，并在几种剂量的肽段的标准生长培养基或巨噬细胞极化培养基（M1和M2）中用rhBMP2处理了这些细胞。我们的读数是细胞活力，细胞凋亡，M1和M2标记的基因表达，以及M​​1标记iNOS和M2标记Arg1的ELISA。我们的数据很少有证据支持单独通过rhBMP2改变巨噬细胞表型，或在富M1或M2培养基中培养时改变表型。这些结果进一步表明，与Infuse临床使用相关的其他因素，可能是超生理rhBMP2剂量和标签外使用，更可能是导致不良预后的罪魁祸首。当条件得到严格控制时，这进一步增强了rhBMP2和其他肽在组织工程治疗中的效用。