摘要
可降解心血管治疗植介入器械已经成为医疗器械开发中的热点。生物医学材料是可降解心血管治疗植介入器械的核心。总结了相关可降解高分子材料的化学物理性质以及降解特性,讨论了可降解心血管植介入器械预期功能与材料性质的关系,并指出了未来可降解医用高分子材料面临的挑战与发展方向。
关键词
心血管疾病是全球范围内最主要的死亡原因之一,其导致的死亡占比已超过40%。我国心血管疾病患者已超过3.3亿人,每年该疾病导致的死亡人数超过400
传统的心血管植介入器械大多由不可降解材料制备,植入后作为异物永久留存体内,容易引起慢性炎症反应,造成周围组织结构功能损伤;且不具备天然心血管组织的生物活性和生理功能,无法像自体组织一样生长代谢修复,容易出现结构衰败以及血栓等问题,制约了其在临床的进一步应
可降解脂肪族聚酯组成成分确定,制备过程可控,具有良好的机械性能和一定的生理环境稳定性,生物相容性良好,降解产物安全,这些优势使得它们被广泛应用于可降解心血管植介入医疗器械的制备。目前已被批准应用于人体植入的可降解脂肪族聚酯主要包括聚乳酸(PLA),聚对二氧环己酮(PDO)、聚己内酯(PCL)和聚羟基乙酸(PGA),它们的化学结构组成、机械物理性质和降解吸收周期等性质均有明显差别(
聚合物名称 | 熔点/℃ | 玻璃化转变温度/℃ | 拉伸强度/MPa | 模量/GPa | 降解周期/月 |
---|---|---|---|---|---|
左旋聚乳酸(PLLA) | 173~178 | 60~65 | 50~70 | 3.0~4.0 | >24 |
聚对二氧环己酮(PDO) | 110 | -10~0 | 30~40 | 1.0~2.0 | 6~12 |
聚己内酯(PCL) | 53~63 | -65~-60 | 约20 | 约0.4 | >24 |
聚羟基乙酸(PGA) | 225~230 | 35~40 | 约115 | 约7.0 | 6~12 |
PLA是一种热塑性聚酯材料,其中乳酸重复单元可分为D型和L型两种构型,即左旋聚乳酸(PLLA)和右旋聚乳酸(PDLA),重复单元的旋光特性对聚乳酸的物理性质有显著影
PDO主链结构中含有大量醚键和酯键,因此具有较高的链柔性,同时也赋予其良好的结晶性
PCL的重复单元为含有6个碳的直链结构,具有良好的链柔性和规整的结构,链段之间的偶极作用较强,因此结晶性能良好。PCL的熔点和玻璃化转变温度较低,分别为53~63 ℃和-60~-65 ℃,在室温下处于高弹态,其拉伸强度(20 MPa)和模量(400 MPa)较低,但具有高延伸率(1 000%
为了使可降解心血管治疗器械植入人体后能够发挥预期功能,在选择和制备用于构建可降解心血管医疗器械的高分子材料时,需要着重考虑材料的机械性能、降解性能和生物性能(

图 1 可降解高分子材料植入后机械性能、降解性能和生物性能变化情况
Fig. 1 Changes in mechanical properties, degrada tion performance, and biological effect of biodegradable polymer materials after implantation
植入早期,可降解心血管治疗器械应当与不可降解器械具有类似的机械功能,例如血管支架应当具备良好的力学支撑性能和介入输送性
可降解心血管治疗器械在植入体内一定时间后,其力学性能会随着材料降解逐渐下降。如材料降解过快而组织修复再生不足,则会存在碎片脱落至血管中的风险,无法实现预期功能;如材料降解周期过长,则降解产物有可能会对周围组织造成持续炎症刺激反应,引起心脏或血管组织功能失常,导致出现血栓、组织过度增生或心脏节律紊乱等问题,并发症风险较高。因此,可降解高分子材料的降解周期应当与心血管组织修复再生过程相匹配。
全降解血管支架已成为心血管支架领域的研究热点(

图 2 全降解聚合物血管支架
Fig. 2 Fully degradable polymer vascular stents
通过可降解高分子材料构建组织工程血管,能够恢复血管的正常功能,可为冠心病的治疗提供新的选择。大部分可降解合成高分子材料能够通过静电纺丝技术制备成柔性多孔的人工小血管,且力学强度能够承受正常的血流压力。然而,可降解高分子材料制备的组织工程小血管依然存在一些不足,主要体现在其顺应性与天然血管存在明显的适配性差异,容易引起吻合口血流动力学紊乱,且植入后的炎症反应会导致内膜过度增生和内皮化延迟,导致血栓和狭窄发生风险,长期通畅率较差,目前尚未进入大规模临床应

图 3 无细胞人工血管构建策略示意
Fig. 3 Steps in construction of human acellular vesse

图 4 无细胞人工血管的微观结
Fig. 4 Ultrastructure of the human acellular vessel matri

图 5 无细胞人工血管作为血液透析通路植入前和植入后的病理学染色图
Fig. 5 Representative pathological staining of human acellular vessels before and after implantatio
心脏封堵器是治疗先天性心脏结构缺损或防治心源性卒中的有效方式,现有心脏封堵器通常采用不可降解镍钛合金材料制备,植入患者心脏后永久留存于体内,易引起组织磨损穿孔等远期并发

图 6 可降解心脏封堵器
Fig. 6 Degradable cardiac occluders
现有可降解高分子材料的机械性能无法完全满足心血管植介入器械在强支撑固定、软组织替代和介入输送等多种使用条件下的力学性能需求,成为利用可降解高分子材料构建心血管植介入器械过程中的最大限制因素。开发高强韧和具有形状记忆性能的新型硬材料,以及开发能够模拟人体心血管组织生物力学性能的新型软材料,将成为未来相当长一段时间内可降解高分子材料开发的主要方向。
现有可降解高分子材料的降解速率与心血管组织的修复或再生速度无法完全匹配,过快或过慢降解均会导致器械功能失效或造成并发症风险。因此,如何控制可降解高分子材料的降解速率以适配不同患者个体和不同植入部位的组织修复再生速度是开发可降解高分子材料过程中面临的一个重要挑战。
可降解心血管植介入器械为心血管疾病的治疗提供了全新的途径和方法,基于可降解高分子材料制备的全降解冠脉支架和全降解心脏封堵器等心血管器械已在我国相继上市,标志着我国在可降解心血管材料研究及器械开发领域已经迈入国际先进水平。随着可降解高分子材料技术的不断发展,预计在不久的将来会有更多的创新型可降解心血管植介入器械问世,为患者带来更好的治疗效果和生活质量。
作者贡献声明
王云兵:论文撰写。
郭高阳:论文共同撰写。
参考文献
马丽媛,王增武,樊静,等.《中国心血管健康与疾病报告2021》概要[J].中国介入心脏病学杂志, 2022, 7: 30. [百度学术]
MA Liyuan, WANG Zengwu, FAN Jing, et al. The synopsis of “Annual Report on Cardiovascular Health and Diseases in China (2021)” [J]. Chinese Journal of Interventional Cardiology, 2022, 7: 30. [百度学术]
WANG Y, LI G, YANG L, et al. Development of innovative biomaterials and devices for the treatment of cardiovascular diseases [J]. Advanced Materials, 2022, 34(46): 2201971. [百度学术]
KURAMITSU S, OHYA M, SHINOZAKI T, et al. Risk factors and long-term clinical outcomes of second-generation drug-eluting stent thrombosis: insights from the REAL-ST registry [J]. Circulation: Cardiovascular Interventions, 2019, 12(6): e007822. [百度学术]
BISSESSOR N. Current perspectives in percutaneous atrial septal defect closure devices [J]. Medical Devices: Evidence and Research, 2015, 8: 297. [百度学术]
OBIWELUOZOR F O, EMECHEBE G A, KIM D W, et al. Considerations in the development of small-diameter vascular graft as an alternative for bypass and reconstructive surgeries: a review [J]. Cardiovascular Engineering and Technology, 2020, 11: 495. [百度学术]
MALIKMAMMADOV E, TANIR T E, KIZILTAY A, et al. PCL and PCL-based materials in biomedical applications [J]. Journal of Biomaterials Science( Polymer Edition), 2018, 29(7/9): 863. [百度学术]
MIDDLETON J C, TIPTON A J. Synthetic biodegradable polymers as orthopedic devices [J]. Biomaterials, 2000, 21(23): 2335. [百度学术]
SABINO M A, GONZáLEZ S, MáRQUEZ L, et al. Study of the hydrolytic degradation of polydioxanone PPDX [J]. Polymer Degradation and Stability, 2000, 69(2): 209. [百度学术]
PARK J M , KIM D S, KIM S R. Nondestructive evaluation of interfacial damage properties for plasma-treated biodegradable poly (p-dioxanone) fiber/poly (L-lactide) composites by micromechanical test and surface wettability [J]. Composites Science and Technology, 2004, 64(6): 847. [百度学术]
GARLOTTA D. A literature review of poly (lactic acid) [J]. Journal of Polymers and the Environment, 2001, 9: 63. [百度学术]
GUPTA B, REVAGADE N, HILBORN J. Poly (lactic acid) fiber: an overview [J]. Progress in Polymer Science, 2007, 32(4): 455. [百度学术]
NAIR L S, LAURENCIN C T. Biodegradable polymers as biomaterials [J]. Progress in Polymer Science, 2007, 32(8): 762. [百度学术]
SABINO M, FEIJOO J, MüLLER A. Crystallisation and morphology of poly (p-dioxanone) [J]. Macromolecular Chemistry and Physics, 2000, 201(18): 2687. [百度学术]
BAI W, CHEN D, LI Q, et al. In vitro hydrolytic degradation of poly (para-dioxanone) with high molecular weight [J]. Journal of Polymer Research, 2009, 16: 471. [百度学术]
FENG Q, JIANG W, SUN K, et al. Mechanical properties and in vivo performance of a novel sliding-lock bioabsorbable poly-p-dioxanone stent [J]. Journal of Materials Science: Materials in Medicine, 2011, 22: 2319. [百度学术]
MARTINS J A, LACH A A, MORRIS H L, et al. Polydioxanone implants: a systematic review on safety and performance in patients [J]. Journal of Biomaterials Applications, 2020, 34(7): 902. [百度学术]
HOUDART R, LAVERGNE A, VALLEUR P, et al. Polydioxanone in digestive surgery: an experimental study [J]. The American Journal of Surgery, 1986, 152(3): 268. [百度学术]
ESHRAGHI S, DAS S. Mechanical and microstructural properties of polycaprolactone scaffolds with one-dimensional, two-dimensional, and three-dimensional orthogonally oriented porous architectures produced by selective laser sintering [J]. Acta Biomaterialia, 2010, 6(7): 2467. [百度学术]
ABEDALWAFA M, WANG F, WANG L, et al. Biodegradable poly-epsilon-caprolactone (PCL) for tissue engineering applications: a review [J]. Reviews on Advanced Materials Science, 2013, 34(2): 123. [百度学术]
SHRIVASTAVA A, DONDAPATI S. Biodegradable composites based on biopolymers and natural bast fibres: a review [J]. Materials Today: Proceedings, 2021, 46: 1420. [百度学术]
ASHAMMAKHI N, ROKKANEN P. Absorbable polyglycolide devices in trauma and bone surgery [J]. Biomaterials, 1997, 18(1): 3. [百度学术]
ORMISTON J A, SERRUYS P W. Bioabsorbable coronary stents [J]. Circulation: Cardiovascular Interventions, 2009, 2(3): 255. [百度学术]
SOMSZOR K, BAS O, KARIMI F, et al. Personalized, mechanically strong, and biodegradable coronary artery stents via melt electrowriting [J]. ACS Macro Letters, 2020, 9(12): 1732. [百度学术]
WANG D, XU Y, LI Q, et al. Artificial small-diameter blood vessels: materials, fabrication, surface modification, mechanical properties, and bioactive functionalities [J]. Journal of Materials Chemistry B, 2020, 8(9): 1801. [百度学术]
HOLZER R, HIJAZI Z M. Interventional approach to congenital heart disease [J]. Current Opinion in Cardiology, 2004, 19(2): 84. [百度学术]
ROH J D, SAWH-MARTINEZ R, BRENNAN M P, et al. Tissue-engineered vascular grafts transform into mature blood vessels via an inflammation-mediated process of vascular remodeling [J]. Proceedings of the National Academy of Sciences, 2010, 107(10): 4669. [百度学术]
HIBINO N, MEJIAS D, PIETRIS N, et al. The innate immune system contributes to tissue-engineered vascular graft performance [J]. The FASEB Journal, 2015, 29(6): 2431. [百度学术]
MORENO K, MURRAY-WIJELATH J, YAGI M, et al. Circulating inflammatory cells are associated with vein graft stenosis [J]. Journal of Vascular Surgery, 2011, 54(4): 1124. [百度学术]
GUPTA P, MANDAL B B. Tissue-engineered vascular grafts: emerging trends and technologies [J]. Advanced Functional Materials, 2021, 31(33): 2100027. [百度学术]
SARKAR S, SALES K M, HAMILTON G, et al. Addressing thrombogenicity in vascular graft construction [J]. Journal of Biomedical Materials Research Part B: Applied Biomaterials, 2007, 82(1): 100. [百度学术]
SáNCHEZ P F, BREY E M, BRICEñO J C. Endothelialization mechanisms in vascular grafts [J]. Journal of Tissue Engineering and Regenerative Medicine, 2018, 12(11): 2164. [百度学术]
杨立, 罗日方, 雷洋, 等. 微创介入全降解血管支架和心脏瓣膜国内外研发现状与研究前沿 [J]. 材料导报, 2019, 33(1): 40. [百度学术]
YANG Li, LUO Rifang, LEI Yang, et al. Frontier research and development of minimally invasive and interventional fully biodegradable stent and heart valve [J]. Materials Reports, 2019, 33(1): 40. [百度学术]
ZONG J, HE Q, LIU Y, et al. Advances in the development of biodegradable coronary stents: a translational perspective [J]. Materials Today Bio, 2022, 16: 100368. [百度学术]
NIKLASON L E, LAWSON J H. Bioengineered human blood vessels [J]. Science, 2020, 370(6513): eaaw8682. [百度学术]
DURáN-REY D, CRISóSTOMO V, SáNCHEZ-MARGALLO J A, et al. Systematic review of tissue-engineered vascular grafts [J]. Frontiers in Bioengineering and Biotechnology, 2021, 9: 771400. [百度学术]
RADKE D, JIA W, SHARMA D, et al. Tissue engineering at the blood-contacting surface: a review of challenges and strategies in vascular graft development [J]. Advanced Healthcare Materials, 2018, 7(15): 1701461. [百度学术]
KIRKTON R D, SANTIAGO-MAYSONET M, LAWSON J H, et al. Bioengineered human acellular vessels recellularize and evolve into living blood vessels after human implantation [J]. Science Translational Medicine, 2019, 11(485): eaau6934. [百度学术]
CHANG W G, NIKLASON L E. A short discourse on vascular tissue engineering [J]. NPJ Regenerative Medicine, 2017, 2(1): 7. [百度学术]
DAHL S L, KYPSON A P, LAWSON J H, et al. Readily available tissue-engineered vascular grafts [J]. Science Translational Medicine, 2011, 3(68): 68ra9. [百度学术]
QUINT C, KONDO Y, MANSON R J, et al. Decellularized tissue-engineered blood vessel as an arterial conduit [J]. Proceedings of the National Academy of Sciences, 2011, 108(22): 9214. [百度学术]
LAWSON J H, GLICKMAN M H, ILZECKI M, et al. Bioengineered human acellular vessels for dialysis access in patients with end-stage renal disease: two phase 2 single-arm trials [J]. The Lancet, 2016, 387(10032): 2026. [百度学术]
LIN C, LIU L, LIU Y, et al. Recent developments in next-generation occlusion devices [J]. Acta Biomaterialia, 2021, 128: 100. [百度学术]
SHI D, KANG Y, ZHANG G, et al. Biodegradable atrial septal defect occluders: a current review [J]. Acta Biomaterialia, 2019, 96: 68. [百度学术]
LI Z, KONG P, LIU X, et al. A fully biodegradable polydioxanone occluder for ventricle septal defect closure [J]. Bioactive Materials, 2023, 24: 252. [百度学术]
GUO G, HU J, WANG F, et al. A fully degradable transcatheter ventricular septal defect occluder: towards rapid occlusion and post-regeneration absorption [J]. Biomaterials, 2022, 291: 121909. [百度学术]
LI B, XIE Z, WANG Q, et al. Biodegradable polymeric occluder for closure of atrial septal defect with interventional treatment of cardiovascular disease [J]. Biomaterials, 2021, 274: 120851. [百度学术]