9.4 EVOLUTION OF CARDIAC FUNCTION AND METABOLISM DURING AGING IN A MURINE ANIMAL MODEL OF OBESITY

Abstract

Purpose/Background/Objectives: Obesity is a well-known risk factor of cardiovascular diseases and a potentially modifiable determinant of arterial ageing. The objectives of this experimental study were to assess the effects of a long-term high fat diet (HFD) on metabolism, adipose tissues and phenotypes of cardiovascular aging. Methods: Murine model chosen was C57BL/6J mice receiving during one year HFD or control diet (CD). Longitudinal follow-up of weight, systolic bloodpressure, heart rate and metabolic parameters was performed. An echocardiographic system was used to study cardiac function. Metabolism at the level of the adipose tissues was studied with FDG positron emission tomography (PET). Results: After 12 months of diet the whole mice showed a positive correlation between plasma leptin level and left ventricular thickness and mass (both p<0.05). As compared with the CD, the HFD was associated with metabolic disorders: higher body weight, hyperglycemia (both p<0.01) and increase in heart rate (p<0.05). Despite lack of modification of the systolic blood pressure, the HFD over 12 months increased left ventricular mass (p<0.01) and thickness of the inter-ventricular septum (p<0.05). Moreover, this parameter was positively correlated to leptin level (p<0.05). Finally, we observed in HFD mice a decrease of glucose metabolism in white fat after 6 months and 12 months and in brown fat only after 12 months (both p<0.01). Conclusions: A long term HFD leads to metabolic disorders and to left ventricular morphological changes. The decrease of glucose metabolism observed in brown fat is compatible with an accelerate process of aging by the HFD.