AFM Characterization of the Internal Mammary Artery as a Novel Target for Arterial Stiffening.

Zhuo Chang,Hans Christian Beck,Lars Melholt Rasmussen,Paolo Paoletti,Maria Lyck Hansen,Riaz Akhtar,Po-Yu Chen

doi:10.1155/2018/6340425

Zhuo Chang, Hans Christian Beck + Show 5 more

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https://doi.org/10.1155/2018/6340425

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Abstract

Using the atomic force microscopy- (AFM-) PeakForce quantitative nanomechanical mapping (QNM) technique, we have previously shown that the adventitia of the human internal mammary artery (IMA), tested under dehydrated conditions, is altered in patients with a high degree of arterial stiffening. In this study, we explored the nanoscale elastic modulus of the tunica media of the IMA in hydrated and dehydrated conditions from the patients with low and high arterial stiffening, as assessed in vivo by carotid-femoral pulse wave velocity (PWV). In both hydrated and dehydrated conditions, the medial layer was significantly stiffer in the high PWV group. The elastic modulus of the hydrated and dehydrated tunica media was significantly correlated with PWV. In the hydrated condition, the expression activity of certain small leucine-rich repeat proteoglycans (SLRPs), which are associated with arterial stiffening, were found to be negatively correlated to the medial elastic modulus. We also compared the data with our previous work on the IMA adventitia. We found that the hydrated media and dehydrated adventitia are both suitable for reflecting the development of arterial stiffening and SLRP expression. This comprehensive study of the nanomechanical properties integrated with the proteomic analysis in the IMAs demonstrates the possibility of linking structural properties and function in small biological samples with novel AFM methods. The IMA is a suitable target for predicting arterial stiffening.

Highlights

In clinical practice, arterial stiffening is commonly assessed with pulse wave velocity (PWV)
The internal mammary artery (IMA) has been used in a parallel study to identify small leucine-rich proteoglycans (SLRPs) which are associated with arterial stiffening [9]
This paper builds on that study [1] which demonstrated with PeakForce quantitative nanomechanical mapping (QNM) atomic force microscopy (AFM) [15, 16] that the adventitia of the IMA is altered in patients with high PWV, in terms of both the nanoscale elastic modulus and the collagen fibril morphology

Summary

Introduction

Arterial stiffening is commonly assessed with pulse wave velocity (PWV). A number of studies have utilized high spatial resolution techniques to probe arterial stiffening in vitro, e.g., [3, 4] These studies are generally restricted to animal models due to obvious challenges in conducting measurements on human aortic tissues. The internal mammary artery (IMA) has emerged as an excellent vessel for studying the pathogenesis of arterial stiffening, especially at the molecular level [5,6,7,8,9] It is readily accessible as the repair artery during coronary artery bypass graft (CABG) operations. This paper builds on that study [1] which demonstrated with PeakForce QNM AFM [15, 16] that the adventitia of the IMA is altered in patients with high PWV, in terms of both the nanoscale elastic modulus and the collagen fibril morphology. The literature on the layer-specific biomechanical properties of the human artery is sparse, and this gap is addressed

Materials and Methods

Results and Discussion

Conclusions