Acharya Gayathri, Armstrong Matthew, McFall Chris, Quinn Rachael W, Hilbert Stephen L, Converse Gabriel L, Toth Peter B, Sherman Ashley K, Lee Chi H, Lofland Gary K, Hopkins Richard A
J Heart Valve Dis. 2014 May;23(3):259-70.
Native, allograft, xenograft and bioprosthetic semilunar valves are all susceptible to calcific degeneration. However, intrinsic differences in baseline calcium and phosphorus tissue concentrations within mammalian normal valve structural components (e.g., cusps, sinus, vessel wall) additionally subdivided by tripartite regions (e.g., right-, left- and non-coronary leaflets) have never been systematically measured and reported. It was originally hypothesized that variations in normative tissue concentrations of calcium and phosphorus may correspond to subsequent clinical patterns of acquired dystrophic calcification; decellularization was also expected to reduce the tissue concentrations of these elements.
Native semilunar valves were freshly harvested from 12 juvenile sheep. Half of the valves were decellularized (six aortic and six pulmonary), while the other valves were flash-frozen at -80 degrees C within minutes of euthanasia as native valves. Elemental calcium and phosphorus concentrations were measured in the great vessels, sinus walls and cusps using inductively coupled plasma optical emission spectrometry (ICP-OES), and analyzed with non-parametric statistical tests.
Calcium concentrations (microg/mg tissue; median (range) were similar in aortic native cusps (0.37 (0.21)), sinus walls (0.37 (0.09)) and aorta (0.37 (0.08)) (p = 0.8298). Pulmonary calcium concentrations were similar in cusps, but 10-25% higher in the native sinus (p = 0.0018) and pulmonary artery (p < 0.0001) compared to analogous aortic structures. All cusps had higher phosphorus concentrations than their respective conduit tissues. No tripartite regional variations were observed. Decellularization did not reduce the calcium content of cusps, but removed 50-55% of vessel and sinus wall calcium. However, up to 85% of phosphorus was removed from all valve tissues (p < 0.001).
There were no significant differences in normal tissue concentrations of calcium between aortic valve functional structures, and no semilunar tripartite regional differences in either semilunar valve complex. Thus, the distribution of baseline tissue calcium content of healthy young valves is not inherently predictive of selective or asymmetric anatomical patterns of valve degenerative calcification. Native semilunar cusps contain the highest phosphorus concentrations. Decellularization reduces all elemental concentrations except for cuspal calcium.
自体、同种异体、异种移植和生物人工合成半月瓣均易发生钙化性退变。然而，哺乳动物正常瓣膜结构成分（如瓣叶、窦、血管壁）内基线钙和磷组织浓度的内在差异，再细分为三个区域（如右冠瓣叶、左冠瓣叶和无冠瓣叶），从未得到系统测量和报道。最初的假设是，钙和磷的正常组织浓度变化可能与随后获得性营养不良性钙化的临床模式相对应；脱细胞处理也有望降低这些元素的组织浓度。
从12只幼年绵羊新鲜采集自体半月瓣。将一半瓣膜进行脱细胞处理（6个主动脉瓣和6个肺动脉瓣），而其他瓣膜在安乐死后几分钟内于-80℃速冻作为自体瓣膜。使用电感耦合等离子体发射光谱法（ICP-OES）测量大血管、窦壁和瓣叶中的钙和磷元素浓度，并进行非参数统计检验。
主动脉瓣自体瓣叶（0.37（0.21））、窦壁（0.37（0.09））和主动脉（0.37（0.08））中的钙浓度（μg/mg组织；中位数（范围））相似（p = 0.8298）。肺动脉瓣叶中的钙浓度相似，但与类似的主动脉结构相比，自体窦（p = 0.0018）和肺动脉（p < 0.0001）中的钙浓度高10-25%。所有瓣叶的磷浓度均高于其各自的管道组织。未观察到三个区域的差异。脱细胞处理并未降低瓣叶的钙含量，但去除了50-55%的血管和窦壁钙。然而，所有瓣膜组织中高达85%的磷被去除（p < 0.001）。
主动脉瓣功能结构之间正常组织钙浓度无显著差异，半月瓣复合体的半月瓣也无三个区域的差异。因此，健康年轻瓣膜基线组织钙含量的分布并非固有地预测瓣膜退行性钙化的选择性或不对称解剖模式。自体半月瓣叶的磷浓度最高。脱细胞处理降低了除瓣叶钙之外的所有元素浓度。
