In vivo polypropylene mesh degradation is hardly a myth
In vivo polypropylene mesh degradation is hardly a myth
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体内聚丙烯网降解并非神话
DOI：
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发表时间：
2017
影响因子：
1.8
通讯作者：
D. Ostergard
中科院分区：
文献类型：
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作者：
Margaret Thompson;S. Guelcher;R. Bendavid;V. Iakovlev;D. Ostergard
尊敬的编辑，我们饶有兴趣地阅读了泰晤士等人的文章。题为“神话：聚丙烯网状物的体内降解”[1]。作者对聚丙烯(PP)网目在活体内发生降解(分解或变质的过程)提出了异议，报道了一种新的清洗方法，该方法使用多次延长超声、振荡和漂白(NaOCl)处理来处理移开的网目样品。评估暴露的表面并不分析移除的材料，他们得出结论，在可解释的网孔上看到的裂纹层-降解聚合物的典型特征-是吸附的蛋白质-甲醛复合体，而不是许多其他出版物所报道的降解的PP。值得注意的是，作者隶属于商业咨询公司Exponent，在这起网状诉讼中，被告聘请了这家公司。此外，根据他们的披露，他们的发现是基于ethcon，Inc.支付的工作[1]。在得出结论时，作者忽略了大量描述PP降解的同行评议文献，也没有解决其他研究人员报告的组织学发现[2-5]。此外，他们的研究使用了一种未经证实和验证的方法，显然是专门设计来非选择性地从网状纤维表面去除所有可分离的物质(包括蛋白质和降解的PP)。聚丙烯是一种热塑性聚合物，众所周知，在体外环境中会发生氧化降解。所有形式的聚丙烯都容易受到三级氢碳键的氧化攻击，导致PP分子链的断裂。这一过程一直持续到不再有PP被氧化为止。降解以裂纹和裂隙的形式出现在外表面，并导致材料的硬化和收缩。通常在PP中添加抗氧化剂以防止聚合物降解，这是外科应用中使用的所有PP网的情况。有大量已发表的文献，估计有100多篇同行评议的文章，接受或描述PP在可变条件下的降解以及其他可植入聚合物在体内的降解。我们不知道有任何其他同行评议的期刊文章支持PP不会像泰晤士等人假设的那样在体内降解的概念。[1]。有相当数量的文献描述了PP的降解，基于对组织适当温和清洁后暴露的PP植入物表面的分析。Liebert等人。[2]1976年，利用傅里叶变换红外光谱(FTIR)测量，报道了在仓鼠皮下植入模型中未稳定的PP长丝在体内氧化的情况。对于分子氧(O2)氧化，108天的诱导时间比Liebert最初估计的要快。这一发现表明，在他们的实验中，细胞分泌的酶或其他化学物质加速了氧化反应。在1998年的一项活体研究中，普理灵®缝线在犬的胸腹部植入了1-2年。作者对这一评论的回复可在doi：10.1007/s00192016-3237-8上找到。
Dear Editor, We read with interest the article by Thames et al. entitled, “The myth: in vivo degradation of polypropylene-based meshes” [1]. The authors dispute the occurrence of degradation (the process of breaking down or deteriorating) of polypropylene (PP) mesh in vivo, reporting a novel cleaning method using multiple cycles of prolonged ultrasonication, shaking, and bleach (NaOCl) treatments of explanted mesh samples. Assessing the exposed surface and not analyzing the material removed, they conclude that the cracked layer—the typical feature of degraded polymer—seen on explanted meshes is an adsorbed protein-formaldehyde complex, rather than degraded PP as reported in numerous other publications. Of note, the authors are affiliated with Exponent, a business consulting firm retained by defendants in the mesh litigation. Furthermore, according to their disclosure, their findings were based on work paid for by Ethicon, Inc. [1]. In drawing their conclusions, the authors ignore the vast body of peer-reviewed literature describing PP degradation and fail to address the histological findings reported by other researchers [2–5]. Furthermore, their investigations utilize an unproven and unvalidated methodology, apparently designed specifically to remove all detachable material nonselectively (including protein and degraded PP) from the surface of the mesh fibers. Polypropylene is a thermoplastic polymer, well known in the ex vivo setting to undergo oxidative degradation. All forms of polypropylene are susceptible to oxidative attack at the tertiary hydrogen–carbon bond, resulting in the breaking of the PP molecular chain. This process continues until no more PP can be oxidized. Degradation appears on the external surface as cracks and fissures and results in hardening and shrinkage of the material. Anti-oxidants are normally added to PP to prevent polymer degradation, as is the case with all PP mesh used in surgical applications. There is a large body of published literature, estimated to be well over 100 peer-reviewed articles, accepting or describing the degradation of PP in variable conditions and the degradation of other implantable polymers in the body.We are not aware of any other peer-reviewed journal article supporting the notion that PP does not degrade in the body, as posited by Thames et al. [1]. There is a substantial volume of literature describing PP degradation based on analysis of the surface of PP implants exposed after appropriate gentle cleaning of the tissue. Liebert et al. [2] in 1976 reported the oxidation of unstabilized PP filaments in vivo in a subcutaneous implantation model in hamsters, using Fourier transform infrared spectroscopy (FTIR) measurements. An induction time of 108 days was faster than originally estimated by Liebert for oxidation by molecular oxygen (O2). This finding suggested that enzymes or other chemicals secreted by cells accelerated the oxidation reaction in their experiment. In a 1998 in vivo study, Prolene® sutures implanted for 1–2 years in a canine thoraco-abdominal An author’s reply to this comment is available at doi:10.1007/s00192016-3237-8.