Siri Saeed, Zhao Yunmei, Maier Franz, Pierce David M, Feng Bin
Department of Biomedical Engineering, University of Connecticut, Storrs, CT 06269, USA.
Lightweight Design and Composite Materials, University of Applied Sciences Upper Austria, 4600 Wels, Austria.
Bioengineering (Basel). 2020 Oct 19;7(4):130. doi: 10.3390/bioengineering7040130.
Many lower gastrointestinal diseases are associated with altered mechanical movement and deformation of the large intestine, i.e., the colon and rectum. The leading reason for patients' visits to gastrointestinal clinics is visceral pain, which is reliably evoked by mechanical distension rather than non-mechanical stimuli such as inflammation or heating. The macroscopic biomechanics of the large intestine were characterized by mechanical tests and the microscopic by imaging the load-bearing constituents, i.e., intestinal collagen and muscle fibers. Regions with high mechanical stresses in the large intestine (submucosa and muscularis propria) coincide with locations of submucosal and myenteric neural plexuses, indicating a functional interaction between intestinal structural biomechanics and enteric neurons. In this review, we systematically summarized experimental evidence on the macro- and micro-scale biomechanics of the colon and rectum in both health and disease. We reviewed the heterogeneous mechanical properties of the colon and rectum and surveyed the imaging methods applied to characterize collagen fibers in the intestinal wall. We also discussed the presence of extrinsic and intrinsic neural tissues within different layers of the colon and rectum. This review provides a foundation for further advancements in intestinal biomechanics by synergistically studying the interplay between tissue biomechanics and enteric neurons.
许多下消化道疾病与大肠（即结肠和直肠）的机械运动和变形改变有关。患者前往胃肠诊所就诊的主要原因是内脏疼痛，这种疼痛可由机械扩张可靠地诱发，而非由炎症或加热等非机械刺激诱发。大肠的宏观生物力学通过机械测试来表征，微观生物力学则通过对承载成分（即肠胶原蛋白和肌纤维）进行成像来表征。大肠中机械应力较高的区域（黏膜下层和固有肌层）与黏膜下神经丛和肌间神经丛的位置重合，这表明肠道结构生物力学与肠神经元之间存在功能相互作用。在本综述中，我们系统地总结了健康和疾病状态下结肠和直肠宏观及微观生物力学的实验证据。我们回顾了结肠和直肠的异质力学特性，并审视了用于表征肠壁胶原纤维的成像方法。我们还讨论了结肠和直肠不同层中存在的外在和内在神经组织。本综述通过协同研究组织生物力学与肠神经元之间的相互作用，为肠道生物力学的进一步发展奠定了基础。
