Chronic heart failure (HF) is a major cause of morbidity and mortality in humans and domestic animals. HF is characterised by chronic inflammation and functional changes in non-cardiovascular tissues; obesity is also associated with low level chronic inflammation, with adipose tissue (AT) exhibiting infiltration of macrophages and alterations in fatty acid (FA) profiles. The aim of this project was to investigate expression of regulators of lipid metabolism and inflammation and fatty acid profiles in AT from a rodent model of HF.
Rats with HF post myocardial infarction were compared with age matched non-failing controls (C)1. Intra-abdominal (IA) and subcutaneous (SC) adipose tissue depots were sampled after humane euthanasia for real-time PCR (QPCR) analysis of stearoyl-CoA desaturase-1 (SCD1), interleukin 1 (IL1) and phosphoenolpyruvate carboxykinase (PCK1). Gas chromatography was used to generate FA profiles and tissue triglyceride (TAG) content was assessed by colourimetric assay. Statistical significance was assessed using ANOVA with post hoc Tukey tests.
In healthy animals SCD1 was significantly lower in SC compared to IA. HF-IA adipose tissue also demonstrated a significant reduction when compared to C-IA (C-IA 1.4±0.06; C-SC 1.0±0.03; and HF-IA 1.17±0.08, P<0.05). PCK was higher in SC compared to IA in control rats (C-IA 0.7±0.05; and C-SC 1.0±0.03, P<0.05), but there was no effect of HF. TAG was significantly higher in HF-IA compared to both C-IA and HF-SC tissue (C-IA 56.8±27.2; HF-IA 199.8±15.4; and HF-SC 111.3±20.6 mg/g, P<0.05). FA analysis identified differences in several species; including reductions in C10, C15 and C17 in HF-SC; however, most interesting was a reduction of both C20:5n3 (EPA) and C22:6n3 (DHEA) in HF-SC.
Despite a reduction in SCD1 expression, we did not detect any difference in mono-unsaturated FA species in the HF rats. EPA and DHEA are essential omega 3 FAs with recognised anti-inflammatory and cardio-protective effects; a reduction in HF suggests altered uptake and metabolism in these animals.
AYale was supported by a Society for Endocrinology Summer Studentship
Reference: 1. Lyon AR, et al. Circulation: arrhythmia and electrophysiology. 2011 4 362.