The usefulness of short-term high-fat/high salt diet as a model of metabolic syndrome in mice.

Diabetic cardiomyopathy (DC) describes diabetes-associated changes in the structure and function of myocardium that are not directly linked to other factors such as hypertension. Currently there are some models of DC; however, they take a large time period to mimic key features. In the present study, we investigated the effects of a short-term high-fat/high salt diet (HFHS) treatment on myocardial function and structure, and vascular reactivity in C57BL/6 male mice. After 14 weeks HFHS induced hypertension (MAP = 144.95 ±â€¯16.13 vs 92.90 ±â€¯18.95 mm Hg), low glucose tolerance (AUC = 1049.01 ±â€¯74.79 vs 710.50 ±â€¯52.57 a.u.), decreased insulin sensitivity (AUC = 429.83 ±â€¯35.22 vs 313.67 ±â€¯19.55 a.u.) and increased adiposity (epididymal fat weight 0.96 ±â€¯0.10 vs 0.59 ±â€¯0.06 OW/BW × 102), aspects present in metabolic syndrome. Cardiac evaluation showed diastolic dysfunction (E/A ratio = 1.20 vs 1.90 u.a.) and cardiomyocyte hypertrophy (cardiomyocyte area = 502.82 ±â€¯31.46 vs 385.58 ±â€¯22.11 µm2). Lastly, vascular reactivity was impaired with higher contractile response (136.10 ±â€¯3.49 vs 120.37 ±â€¯5.43%) and lower response to endothelium-dependent vasorelaxation (74.01 ±â€¯4.35 vs 104.84 ±â€¯3.57%). In addition, the diet was able to induce an inward coronary remodeling (vascular total area: SCNS 6185 ±â€¯800.6 vs HFHS 4085 ±â€¯213.7 µm2). Therefore, we conclude that HFHS short-term treatment was able to induce metabolic syndrome-like state, cardiomyopathy and vascular injury working as an important tool to study cardiometabolic diseases.

Effects of Dietary Macronutrient Composition on FNDC5 and Irisin in Mice Skeletal Muscle.

BACKGROUND: Fibronectin type III domain containing 5 (FNDC5) and its protein product Irisin are therapeutic targets for obesity-associated disorders. Irisin plays an important role in energy regulation, inducing browning of white adipocytes, and improving obesity. We aimed to investigate the association between muscle Irisin expression and dietary quality. METHODS: Twenty-eight female mice were divided into four groups and fed the following experimental diets for 60 days: standard diet (SD), high-carbohydrate diet (HCD), high-fat diet (HFD), and high-protein diet (HPD). We evaluated body weight, food intake, serum total cholesterol, triacylglycerol, and glucose. We also performed glucose tolerance and insulin sensitivity tests. Expression of FNDC5 was evaluated by quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) of soleus muscle. Western blot was used to assess Irisin protein expression. RESULTS: The major finding of the present study was that HFD and HCD were associated with a downregulation of FNDC5. In addition to these results, we noted a significant reduction in skeletal muscle Irisin level. HPD prevented reductions of both FNDC5 and Irisin levels, as well as increased brown adipose tissue, compared to the control group. CONCLUSIONS: In conclusion, we observed that the HPD type of diet can change both FNDC5 expression and Irisin levels. Thus, the HPD might be the most appropriate diet to achieve high amounts of Irisin, a target molecule for the treatment of obesity and its co-morbidities.