Korossis Sotiris A, Booth Catherine, Wilcox Helen E, Watterson Kevin G, Kearney John N, Fisher John, Ingham Eileen
School of Mechanical Engineering, University of Leeds, UK.
J Heart Valve Dis. 2002 Jul;11(4):463-71.
For both young patients with congenital heart disease and young, growing adults there is a need for replacement heart valves that will develop with the patient. Tissue-engineered heart valves coupled with in-vitro recellularization have this potential. One approach is to use acellular tissue matrices, but the decellularization treatment must not affect the biomechanical integrity of the valvular matrix. This study investigated the effect of 0.03% (w/v) and 0.1% (w/v) sodium dodecyl sulfate (SDS) on the mechanical integrity of porcine aortic valve leaflets.
Left coronary porcine leaflets were treated with SDS (0.03% or 0.1%, w/v) in hypotonic or isotonic buffer and buffer alone. SDS in hypotonic buffer produced accellularity. Circumferential and radial specimens of treated leaflets were subjected to uniaxial tensile testing, and the effect of the buffer on leaflet morphology was assessed. Whole porcine aortic roots were also treated with 0.1% (w/v) SDS and subjected to function testing.
SDS treatment significantly increased extensibility of the leaflet specimens, which was greater in the circumferential than radial direction. This was seen as a significantly decreased slope of both the elastic and collagen phases of the stress-strain behavior. The ultimate tensile strength and transition stress were not affected significantly; nor was there any significant difference between hypotonic buffer and hypotonic buffer + SDS treatments. Study of the leaflet morphology suggested that the increased extensibility was due to shrinkage as well as to increased hydration of the treated leaflets caused by the hypotonic buffer.
SDS treatment produced a more extensible tissue with equal strength compared with the fresh aortic valve. Functionality experiments with SDS-treated whole aortic roots showed complete valve leaflet competence under physiological pressures (120 mmHg) as well as physiological leaflet kinematics.
对于患有先天性心脏病的年轻患者以及正在成长的年轻成年人而言，都需要能够随患者生长发育的置换心脏瓣膜。结合体外再细胞化的组织工程心脏瓣膜具有这种潜力。一种方法是使用去细胞组织基质，但去细胞处理不能影响瓣膜基质的生物力学完整性。本研究调查了0.03%（w/v）和0.1%（w/v）的十二烷基硫酸钠（SDS）对猪主动脉瓣叶机械完整性的影响。
将猪左冠状动脉瓣叶在低渗或等渗缓冲液以及仅缓冲液中用SDS（0.03%或0.1%，w/v）处理。低渗缓冲液中的SDS可产生去细胞效果。对处理后的瓣叶进行周向和径向标本的单轴拉伸试验，并评估缓冲液对瓣叶形态的影响。全猪主动脉根部也用0.1%（w/v）SDS处理并进行功能测试。
SDS处理显著增加了瓣叶标本的延展性，周向方向的延展性大于径向方向。这表现为应力-应变行为的弹性和胶原阶段的斜率均显著降低。极限拉伸强度和转变应力未受到显著影响；低渗缓冲液处理与低渗缓冲液+SDS处理之间也没有显著差异。对瓣叶形态的研究表明，延展性增加是由于低渗缓冲液导致处理后的瓣叶收缩以及水合作用增强。
与新鲜主动脉瓣相比，SDS处理产生了一种强度相同但更具延展性的组织。对经SDS处理的全主动脉根部进行的功能实验表明，在生理压力（120 mmHg）下瓣膜叶完全具备功能，且叶的运动学符合生理状态。
