Intermedin Ameliorates Atherosclerosis by Increasing Cholesterol Efflux Through the cAMP-PKA Pathway in Macrophage RAW264.7 Cell Line.

BACKGROUND The aim of this study was to explore the role of intermedin and its mechanism in cholesterol efflux of macrophage THP-1 and RAW264.7 cell lines in atherosclerosis (AS). MATERIAL AND METHODS ApoE-/- mice were fed with a high-fat diet, and the concentrations of total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were measured. The lipidoses of the aortic sinus were analyzed by hematoxylin and eosin staining, and the cAMP level was detected by enzyme-linked immunosorbent assay (ELISA). The expressions of ATP-binding cassette transporter (ABCA1) were tested by real-time PCR and Western blot analysis. RESULTS IMD decreased serum TC and LDL-C, and increased serum HDL-C level in apoE-/- mice and attenuated AS plaque areas. In vitro, IMD increased intracellular cAMP concentration in a dose-dependent manner in THP-1 and RAW264.7 cell lines, which enhanced the expression of ABCA1 and increased cholesterol efflux rate. However, this effect was inhibited by PKAI in the RAW 264.7 cell line but not in the THP-1 cell line. CONCLUSIONS IMD can ameliorate the development of AS in ApoE-/- mice and regulate cholesterol balance in the RAW264.7 cell line through the cAMP-PKA pathway.

Intermedin inhibits uptake of oxidized LDL via CD36 pathway in RAW264.7 cells.

Intermedin (IMD) exerts a potent function in preventing atherosclerosis, while the mechanism remains unclear. Here we investigated the potential molecular mechanism responsible for the protective function of IMD in preventing foam cell formation in RAW264.7 cells. In our present study, IMD significantly inhibited intracellular cholesterol accumulation. Additionally, IMD dose-dependently down-regulated CD36 expression, which was confirmed by real-time quantitative reverse transcription-PCR and Western blot analysis. Our data suggest that IMD could inhibit the formation of foam cells through, at least partly, a CD36-dependent mechanism. This study suggests that IMD may be a therapeutic candidate for treating atherosclerosis.

[Relationship between intermedin and atrial fibrosis in patients of hypertension combined with atrial fibrillation].

This study was aimed to evaluate the relationship between the changes of plasma intermedin (IMD) and atrial fibrosis in hypertensive patients with atrial fibrillation. During the period from 2010 to 2011, appropriate 150 subjects of out-patients (female 50%, male 50%) were selected in West China Hospital, Sichuan University, and were divided into three groups: the hypertension-only group, the hypertension combined with paroxysmal atrial fibrillation group and the hypertension combined with persistent atrial fibrillation group. Firstly, we collected the Physical examination results and medical history records of the patients. We then performed ultrasound cardiogram and blood biochemical tests on the patients. We also detected the plasma IMD and transforming growth factor ß1 (TGF-ß1) using ELISA. The results showed that compared with the hypertensive group, the plasma level of IMD, TGF-ß1 and left atrium director (LAD) in the hypertensive combined with atrial fibrillation group were higher significantly. Compared with the paroxymal atrial fibrillation group, the levels of IMD, TGF-ß1 and LAD were higher significantly in persistent atrial fibrillation group. Analysis of correlation and partial correlation showed that IMD was positively correlated with TGF-p1 (r=0.51, P<0. 001), IMD was positively correlated with LAD(r=0.59, P< 0.001), and TGF-ß1 was positively correlated with LAD (r = 0.57, P < 0.001). The results suggest that IMD might suppress the pathophysiological process of atrial fibrillation.