A Novel iRFP-Incorporated in vivo Murine Atherosclerosis Imaging System

• Published in: Scientific reports Vol. 8; no. 1; pp. 14515 - 11
• Main Authors: Kulathunga, Kaushalya, Hamada, Michito, Hiraishi, Yukiko, Otake, Mao, Tran, Mai Thi Nhu, Cheng, Olivia, Tanaka, Junko, Sakasai, Tomoki, Sakaguchi, Shota, Sugiyama, Yuka, Fleischmann, Bernd K., Takahashi, Satoru, Miwa, Yoshihiro
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 28-09-2018; Nature Publishing Group; Nature Portfolio
• Subjects: 14/35; 631/1647/245/2225; 631/61/17/1511; 64/110; 64/60; Actin; Actins - genetics; Animals; Aorta; Aortic Diseases - diagnostic imaging; Aortic Diseases - genetics; Arteriosclerosis; Atherosclerosis; Atherosclerosis - diagnostic imaging; Atherosclerosis - etiology; Atherosclerosis - genetics; Atherosclerosis Induction; Azo Compounds; Bone marrow; Bone Marrow Transplantation; Cholesterol; Cholesterol, Dietary - toxicity; Coloring Agents; Coronary vessels; Flow Cytometry; Genes, Reporter; Genes, Synthetic; Humanities and Social Sciences; In Vivo Imaging System (IVIS); IVIS Images; Low density lipoprotein receptors; Luminescent Measurements - methods; Luminescent Proteins - analysis; Luminescent Proteins - genetics; Macrophages; Macrophages, Peritoneal - chemistry; Macrophages, Peritoneal - ultrastructure; Mice; Mice, Transgenic; Microscopy, Fluorescence; multidisciplinary; Near-infrared Fluorescent Protein; Optical Imaging - methods; Plaque Macrophages; Plaque, Atherosclerotic - diagnostic imaging; Plaques; Promoter Regions, Genetic; Receptor density; Receptors, LDL - deficiency; Recombinant Proteins - analysis; Recombinant Proteins - genetics; Rodents; Science; Science (multidisciplinary); Thorax; In Vivo Imaging System (IVIS); Plaque Macrophages; Near-infrared Fluorescent Protein; IVIS Images; Atherosclerosis Induction
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-32456-5

By using near-infrared fluorescent protein (iRFP)-expressing hematopoietic cells, we established a novel, quantitative,
in vivo
, noninvasive atherosclerosis imaging system. This murine atherosclerosis imaging approach targets macrophages expressing iRFP in plaques. Low-density lipoprotein receptor-deficient (
LDLR
−/−
) mice transplanted with beta-actin promoter-derived iRFP transgenic (TG) mouse bone marrow (BM) cells (iRFP → 
LDLR
−/−
) were used. Atherosclerosis was induced by a nonfluorescent 1.25% cholesterol diet (HCD). Atherosclerosis was compared among the three differently induced mouse groups. iRFP → 
LDLR
−/−
mice fed a normal diet (ND) and
LDLR
−/−
mice transplanted with wild-type (WT) BM cells were used as controls. The
in vivo
imaging system (IVIS) detected an enhanced iRFP signal in the thoracic aorta of HCD-fed iRFP → 
LDLR
−/−
mice, whereas iRFP signals were not observed in the control mice. Time-course imaging showed a gradual increase in the signal area, which was correlated with atherosclerotic plaque progression. Oil red O (ORO) staining of aortas and histological analysis of plaques confirmed that the detected signal was strictly emitted from plaque-positive areas of the aorta. Our new murine atherosclerosis imaging system can noninvasively image atherosclerotic plaques in the aorta and generate longitudinal data, validating the ability of the system to monitor lesion progression.