title: Cardiac function and lipid distribution in rats fed a high-fat diet: in vivo magnetic resonance imaging and spectroscopy.
abstract: Obesity is a major risk factor in the development of cardiovascular disease, type 2 diabetes, and its pathophysiological precondition insulin resistance. Very little is known about the metabolic changes that occur in the myocardium and consequent changes in cardiac function that are associated with high-fat accumulation. Therefore, cardiac function and metabolism were evaluated in control rats and those fed a high-fat diet, using magnetic resonance imaging, magnetic resonance spectroscopy, mRNA analysis, histology, and plasma biochemistry. Analysis of blood plasma from rats fed the high-fat diet showed that they were insulin resistant (P < 0.001). Our high-fat diet model had higher heart weight (P = 0.005) and also increasing trend in septal wall thickness (P = 0.07) compared with control diet rats. Our results from biochemistry, magnetic resonance imaging, and mRNA analysis confirmed that rats on the high-fat diet had moderate diabetes along with mild cardiac hypertrophy. The magnetic resonance spectroscopy results showed the extramyocellular lipid signal only in the spectra from high-fat diet rats, which was absent in the control diet rats. The intramyocellular lipids in high-fat diet rats was higher (8.7%) compared with rats on the control diet (6.1%). This was confirmed by electron microscope and light microscopy studies. Our results indicate that lipid accumulation in the myocardium might be an early indication of the cardiovascular pathophysiology associated with type 2 diabetes.
authors.affiliation: Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, A*STAR, Singapore.
authors.forename: Vijayasarathi
authors.initials: V
authors.lastname: Nagarajan
authors.forename: Venkatesh
authors.initials: V
authors.lastname: Gopalan
authors.forename: Manami
authors.initials: M
authors.lastname: Kaneko
authors.forename: Veronique
authors.initials: V
authors.lastname: Angeli
authors.forename: Peter
authors.initials: P
authors.lastname: Gluckman
authors.forename: Arthur Mark
authors.initials: AM
authors.lastname: Richards
authors.forename: Philip W
authors.initials: PW
authors.lastname: Kuchel
authors.forename: S Sendhil
authors.initials: SS
authors.lastname: Velan
mesh_terms: D000818:Animals; D001391:Azo Compounds; D001786:Blood Glucose; D001835:Body Weight; D006332:Cardiomegaly / Q000503:physiopathology; D004396:Coloring Agents; D059305:Diet, High-Fat; D004435:Eating; D006321:Heart / Q000187:drug effects*; D007333:Insulin Resistance / Q000502:physiology; D050356:Lipid Metabolism / Q000187:drug effects*; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008855:Microscopy, Electron, Scanning; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D009765:Obesity / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D011916:Rats, Inbred F344; D060888:Real-Time Polymerase Chain Reaction; D014280:Triglycerides / Q000378:metabolism
chemical_list: D001391:Azo Compounds; D001786:Blood Glucose; D004396:Coloring Agents; D012333:RNA, Messenger; D014280:Triglycerides; C011049:oil red O
keywords: EMCL; IMCL; cardiac function; cardiac metabolism