The Correlation Between The Expression Of NLRP3 Inflammasome In Carotid Plaque And The Histological Characteristics Of Plaque

BACKGROUND AND PURPOSE:NLRP3 inflammasome is a complex composed of NLRP3,ASC and caspase-1 proteins,which can regulate the level of inflammation by regulating the production and activation of IL-1β and IL-18.The expression level of NLRP3 inflammasome is thought to be related to the progression of atherosclerosis.However,the correlation between its expression level and the histological characteristics of carotid plaques and the symptoms of patients remains unclear.METHODS:A total of 51 patients were enrolled in the study.Patients were divided into symptomatic and nonsymptomatic groups based on ipsilateral ischemia-related symptoms.Carotid plaques were obtained from 29 asymptomatic and 22 symptomatic patients undergoing carotid endarterectomy(CEA).The expression of NLRP3 inflammasome and its related cytokines in plaques was assessed by immunohistochemistry,and the relationship between the expression level and plaque vulnerability was evaluated.RESULTS:(1)There was no significant difference in baseline characteristics and the expression level of NLRP3 inflammasome in carotid plaque between the symptomatic group and the asymptomatic group;(2)There was no significant difference in the histological characteristics of carotid plaques between the symptomatic group and the asymptomatic group;The expression level of NLRP3 inflammasome in carotid plaque was significantly correlated with IL-1β(r=0.672,P<0.01),IL-18(r=0.580,P<0.01).The expression of NLRP3 inflammasome and the size of lipid core in carotid plaque(r=0.669,P<0.01),the number of macrophages(r=0.559,P<0.05)and the number of new capillaries(r=0.344,P<0.05),and positively correlated with the fibrous cap thickness(r=-0.673,P<0.01),collagen fiber content in plaque(r=-0.216,P<0.01).Plaques with high expression of NLRP3 inflammasome were more likely to show the appearance characteristics of vulnerable plaques(r=0.759,P<0.01);There was no statistically significant correlation between baseline characteristics of patients and the expression level of NLRP3 inflammasome in plaques.CONCLUSIONS:The increased expression of NLRP3 inflammasome and its involved regulation of chronic inflammatory pathways may be one of the mechanisms leading to plaque instability in patients with carotid atherosclerosis.This pathway may affect the stability of the plaque by changing the composition(collagen fiber content,the number of smooth muscle cells and macrophages)and the structural characteristics(lipid core size,fibrous cap thickness,and the number of new capillaries)of the plaque.Plaques with higher NLRP3 inflammasome expression tended to be more unstable.Further studies are needed to determine the potential mechanistic link between NLRP3 inflammasome expression and histological features of plaques and plaque stability.