Mouse models of abdominal aortic aneurysm (AAA) and dissection have proven to be invaluable in the advancement of diagnostics and therapeutics by providing a platform to decipher response variables that are elusive in human populations. One such model involves systemic Angiotensin II (Ang-II) infusion into low density-lipoprotein receptor-deficient (LDLr−/−) mice leading to intramural thrombus formation, inflammation, matrix degradation, dilation, and dissection. Despite its effectiveness, considerable experimental variability has been observed in AAAs taken from our Ang-II infused LDLr−/− mice (n = 12) with obvious dissection occurring in 3 samples, outer bulge radii ranging from 0.73 to 2.12 mm, burst pressures ranging from 155 to 540 mmHg, and rupture location occurring 0.05 to 2.53 mm from the peak bulge location. We hypothesized that surface curvature, a fundamental measure of shape, could serve as a useful predictor of AAA failure at supra-physiological inflation pressures. To test this hypothesis, we fit well-known biquadratic surface patches to 360o micro-mechanical test data and used Spearman’s rank correlation (rho) to identify relationships between failure metrics and curvature indices. We found the strongest associations between burst pressure and the maximum value of the first principal curvature (rho = −0.591, p-val = 0.061), the maximum value of Mean curvature (rho = −0.545, p-val = 0.087), and local values of Mean curvature at the burst location (rho = −0.864, p-val = 0.001) with only the latter significant after Bonferroni correction. Additionally, the surface profile at failure was predominantly convex and hyperbolic (saddle-shaped) as indicated by a negative sign in the Gaussian curvature. Findings reiterate the importance of shape in experimental models of AAA.

中文翻译：

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腹主动脉瘤和夹层小鼠模型曲率与破裂的关系

腹主动脉瘤 (AAA) 和解剖的小鼠模型已被证明在诊断和治疗的进步中是非常宝贵的，因为它提供了一个平台来破译在人群中难以捉摸的反应变量。一种这样的模型涉及全身血管紧张素 II (Ang-II) 输注到低密度脂蛋白受体缺陷 (LDLr-/-) 小鼠中，导致壁内血栓形成、炎症、基质降解、扩张和解剖。尽管其有效，但在取自注入 Ang-II 的 LDLr-/- 小鼠（n = 12）的 AAAs 中观察到相当大的实验变异性，在 3 个样本中发生了明显的解剖，外凸半径范围为 0.73 至 2.12 毫米，爆破压力范围为从 155 到 540 mmHg，破裂位置发生在距峰值凸起位置 0.05 到 2.53 mm 处。我们假设表面曲率，一种基本的形状测量，可以作为超生理膨胀压力下 AAA 失效的有用预测因子。为了检验这一假设，我们将众所周知的双二次曲面片拟合到 360o 微机械测试数据，并使用 Spearman 秩相关 (rho) 来识别失效度量和曲率指数之间的关系。我们发现爆破压力与第一主曲率的最大值 (rho = -0.591, p-val = 0.061)、平均曲率的最大值 (rho = -0.545, p-val = 0.087) 和爆发位置的平均曲率的局部值（rho = -0.864，p-val = 0.001），在 Bonferroni 校正后只有后者显着。此外，失效时的表面轮廓主要是凸面和双曲线（马鞍形），如高斯曲率中的负号所示。研究结果重申了形状在 AAA 实验模型中的重要性。