Gladstone Institute of Cardiovascular Disease, J. David Gladstone Institutes, 1650 Owns Street, San Francisco, CA 94158, USA.
Aarhus Institute of Advanced Sciences (AIAS), Aarhus University, 8000 Aarhus C, Denmark.
J Exp Biol. 2022 Jul 1;225(13). doi: 10.1242/jeb.244419.
The walls of the mammalian aorta and pulmonary artery are characterized by diverging morphologies and mechanical properties, which have been correlated with high systemic and low pulmonary blood pressure, as a result of intraventricular pressure separation. However, the relationship between intraventricular pressure separation and diverging aortic and pulmonary artery wall morphologies and mechanical characteristics is not understood. The snake cardiovascular system poses a unique model for the study of this relationship, as representatives both with and without intraventricular pressure separation exist. In this study, we performed uniaxial tensile testing on vessel samples taken from the aortas and pulmonary arteries of the Madagascar ground boa, Acrantophis madagascariensis, a species without intraventricular pressure separation. We then compared these morphological and mechanical characteristics with samples from the ball python, Python regius, and the yellow anaconda, Eunectes notaeus - species with and without intraventricular pressure separation, respectively. Our data suggest that although the aortas and pulmonary arteries of A. madagascariensis respond similarly to the same intramural blood pressure, they diverge in morphology, and that this attribute extends to E. notaeus. In contrast, P. regius aortas and pulmonary arteries diverge both morphologically and in terms of their mechanical properties. Our data indicate that intraventricular pressure separation cannot fully explain diverging aortic and pulmonary artery morphologies. Following the law of Laplace, we propose that pulmonary arteries of small luminal diameter represent a mechanism to protect the fragile pulmonary vasculature by reducing the blood volume that passes through, to which genetic factors may contribute more strongly than physiological parameters.
哺乳动物的主动脉和肺动脉壁具有不同的形态和力学特性，这与心室间压力分离导致的高体循环血压和低肺血压有关。然而，心室间压力分离与不同的主动脉和肺动脉壁形态和力学特性之间的关系尚不清楚。蛇的心血管系统为研究这种关系提供了一个独特的模型，因为既有具有心室间压力分离的代表，也有无心室间压力分离的代表。在这项研究中，我们对来自马达加斯加地蟒（Acrantophis madagascariensis）的主动脉和肺动脉的血管样本进行了单轴拉伸测试，该物种没有心室间压力分离。然后，我们将这些形态和力学特性与来自球蟒（Python regius）和黄色水蟒（Eunectes notaeus）的样本进行了比较，这两个物种分别具有和不具有心室间压力分离。我们的数据表明，尽管 A. madagascariensis 的主动脉和肺动脉对相同的壁内血压反应相似，但它们在形态上存在差异，而这一属性也延伸到了 E. notaeus。相比之下，P. regius 的主动脉和肺动脉在形态和力学特性上都存在差异。我们的数据表明，心室间压力分离不能完全解释不同的主动脉和肺动脉形态。根据拉普拉斯定律，我们提出小腔径的肺动脉通过减少通过的血量来保护脆弱的肺血管，这一机制可能更多地受到遗传因素的影响，而不是生理参数。
