The effects of ultrasound-targeted microbubble destruction (UTMD) carrying IL-8 monoclonal antibody on the inflammatory responses and stability of atherosclerotic plaques

Abstract

This study investigated the value of using ultrasound-targeted microbubble destruction (UTMD) to deliver an IL-8 monoclonal antibody to inhibit the inflammatory response and increase plaque stability in a rabbit model of atherosclerosis (AS). An abdominal aortic atherosclerotic plaque model was established in sixty 4-week-old male New Zealand rabbits. The rabbits were fed a high-fat diet for 12 weeks. On the 12^th week, the abdominal aorta was subjected to both balloon-induced mechanical injury and bovine serum albumin-induced immunological injury. After these injuries were established, the rabbits were fed a high-fat diet for 8 additional weeks. On the 20^th week, the rabbits were divided into three groups: the pretreatment (PT) group, the control group, and the IL-8 group. The ultrasonic parameters and histological data associated with the plaques from the PT group were acquired on the 20^th week after targeted contrast-enhanced ultrasonography (CEUS) was performed. The rabbits in the IL-8 and control groups received targeted CEUS and UTMD every 2 weeks. A targeted contrast agent carrying IL-8 monoclonal antibody was used for the IL-8 group, whereas normal saline was used for the control group. The rabbits in these two groups underwent the same procedure four times beginning during the 20^th week. On the 26^th week after UTMD, ultrasonic parameters and histological data were collected. The peak intensity (PI), microvessel density (MVD), and macrophage count of the PT group were significantly higher than those of both the control and IL-8 groups (P < 0.05). Additionally, these three parameters were higher in the control group than in the IL-8 group (P < 0.05). The two-dimensional (2D) ultrasonic parameters, including the maximum thickness of the plaque and the intima-media thickness (IMT), did not differ significantly among the three groups (P > 0.05). PI, MVD, and macrophage count were positively correlated with each other (r=0.564, r=0.6034, and r=0.536, respectively; P<0.05). UTMD-delivered IL-8 monoclonal antibodies alleviate inflammation within atherosclerotic plaques. UTMD is a novel and effective method for plaque stabilization.

Keywords: Atherosclerosis; Contrast-enhanced ultrasonography; Inflammatory response; Ultrasound-targeted microbubble destruction.