Avaliação temporal das alterações cardíacas induzidas por dieta rica em carboidratos refinados: participação de mediadores inflamatórios

Abstract

Carbohydrate intake has increased across the last century and has become a major public health threat. In addition, epidemiological studies demonstrate clear and positive correlation between high carbohydrate (HC) intake and cardiovascular risk factors and mortality. However, there is a lack of knowledge regarding the relationship between high carbohydrate consumption, inflammation, cardiac morphology, and function. For this reason, according to the approval CEUA protocol sheet (193/2015), it is aimed to assess the effects from a HC diet on mouse hearts through different intake times. Then, Balb/c mice were fed with chow or HC diet during 2 (2HC), 4 (4HC), or 8 (8HC) weeks and euthanized at the same age (14 weeks old). The HC diet was comprised of 45% chow diet, 45% condensed milk and 10% refined sugar. Metabolic, hemodynamic, histological, functional, and molecular characteristics were analysed. It was observed an increase of the cardiac weight in all groups exposed to the HC diet, which resulted in enhanced relative wall thickness on four and eight weeks of HC diet consumption. In vivo cardiac function assessment demonstrated systolic dysfunction in all HC groups and diastolic dysfunction among animals with 8 weeks of HC diet consumption. Systolic and diastolic function were assessed through maximum and minimum dP/dT, respectively. Similarly, ex vivo analysis showed reduced maximum effect (Emax) from isoprenaline over maximum and minimum dP/dT in all HC groups. These findings were blood pressure independent. Furthermore, it was observed reduced IL-10 cardiac levels in all times of HC diet consumption, enhanced lipid peroxidation on the 2HC and 4HC groups, elevated matrix metalloproteinase type 2 (MMP-2) levels on the 4HC group, and increased cardiac TNF-α concentration on the 8HC group. Therefore, HC diet led to left ventricular concentric remodeling and reduced contractility function. Diminished IL-10 cardiac levels were observed in parallel to morphofunctional modification from two weeks of HC diet intake. Meanwhile, high reactive oxygen species (2nd and 4th week), MMP-2 (4th week) and TNF-α (8th week) production contributed to cardiac remodeling and dysfunction sustenance.