The endothelium is crucial for maintaining vascular homeostasis and functions as a barrier between blood components and tissue. In atherosclerosis, this barrier function is impaired, which is characterized by secretion of chemoattractants and cytokines, upregulation of adhesion molecules and increased vascular permeability. This facilitates enhanced leukocyte migration through the vessel wall. Fortunately, we can utilize these features to our advantage by using nanomedicine to deliver drugs and imaging tracers into the interstitial space. This provides us with targeted, local delivery of therapeutic agents, which enhances the specificity and efficacy of these agents and thus, could be used to inhibit disease progression. Additionally, delivery of imaging tracers in the interstitial space will give us insight into the vulnerability of atherosclerotic plaques by targeting resident macrophages and activated endothelial cells, providing pivotal information that is currently lacking in the clinic. In this review, we discuss how the endothelial barrier is affected during atherosclerosis and how to surmount this barrier for successful delivery of nanomedicine carrying drugs and imaging tracers to both the endothelium and macrophages.

中文翻译：

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克服内皮屏障以输送药物和成像示踪剂

内皮对于维持血管稳态至关重要，并作为血液成分和组织之间的屏障发挥作用。在动脉粥样硬化中，这种屏障功能受损，其特征是化学引诱物和细胞因子的分泌、粘附分子的上调和血管通透性的增加。这有助于增强白细胞通过血管壁的迁移。幸运的是，我们可以通过使用纳米医学将药物和成像示踪剂输送到间隙空间来利用这些特征。这为我们提供了治疗剂的靶向局部递送，从而增强了这些药物的特异性和功效，因此可用于抑制疾病进展。此外，通过靶向驻留巨噬细胞和活化的内皮细胞，在间质空间中传递成像示踪剂将使我们深入了解动脉粥样硬化斑块的脆弱性，提供目前临床缺乏的关键信息。在这篇综述中，我们讨论了动脉粥样硬化期间内皮屏障如何受到影响，以及如何克服这一屏障，成功地将携带药物和成像示踪剂的纳米药物输送到内皮细胞和巨噬细胞。