Effects of high intensity interval training on neuro-cardiovascular dynamic changes and mitochondrial dysfunction induced by high-fat diet in rats

This research was supported by the Brazilian National Council for Scientific and Technologic Development (CNPq) (Grant number: 474116/2008-5) and Carlos Chagas Filho Foundation for Research Support in the State of Rio de Janeiro (FAPERJ) (Grant number: E-26/ 111.732/2011), both received by Eliete Bouskela. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Effects of Incretin-Based Therapies on Neuro-Cardiovascular Dynamic Changes Induced by High Fat Diet in Rats.

BACKGROUND AND AIMS:Obesity promotes cardiac and cerebral microcirculatory dysfunction that could be improved by incretin-based therapies. However, the effects of this class of compounds on neuro-cardiovascular system damage induced by high fat diet remain unclear. The aim of this study was to investigate the effects of incretin-based therapies on neuro-cardiovascular dysfunction induced by high fat diet in Wistar rats. METHODS AND RESULTS:We have evaluated fasting glucose levels and insulin resistance, heart rate variability quantified on time and frequency domains, cerebral microcirculation by intravital microscopy, mean arterial blood pressure, ventricular function and mitochondrial swelling. High fat diet worsened biometric and metabolic parameters and promoted deleterious effects on autonomic, myocardial and haemodynamic parameters, decreased capillary diameters and increased functional capillary density in the brain. Biometric and metabolic parameters were better improved by glucagon like peptide-1 (GLP-1) compared with dipeptdyl peptidase-4 (DPP-4) inhibitor. On the other hand, both GLP-1 agonist and DPP-4 inhibitor reversed the deleterious effects of high fat diet on autonomic, myocardial, haemodynamic and cerebral microvascular parameters. GLP-1 agonist and DPP-4 inhibitor therapy also increased mitochondrial permeability transition pore resistance in brain and heart tissues of rats subjected to high fat diet. CONCLUSION:Incretin-based therapies improve deleterious cardiovascular effects induced by high fat diet and may have important contributions on the interplay between neuro-cardiovascular dynamic controls through mitochondrial dysfunction associated to metabolic disorders

Experimental swelling protocol induced by Ca²⁺.

<p>Liraglutide and sitagliptin subgroups showed increased mitochondrial permeability transition pore resistance in brain (a) and heart (b) tissues. Analyses were made in rats having received liraglutide and sitagliptin for 4 weeks after high fat diet during 18 weeks. Data are shown as mean ± SEM; <i>n</i> = 5.</p

Biometric, cumulative caloric intake, glucose and myocardial parameters after diets and incretin-based therapies.

<p>Biometric, cumulative caloric intake, glucose and myocardial parameters after diets and incretin-based therapies.</p

Composition of standard chow and high-fat diet.

<p>Composition of standard chow and high-fat diet.</p

Effects of high fat diet and incretin-based-therapies on autonomic nervous system.

<p><b>(a)</b> Effects of high fat diet alone or in combination with liraglitude or sitagliptin treatments on R-R intervals and time-domain parasympathetic indexes of heart rate variability (SDNN, pNN5% and RMSSD). (<b>b</b>) Effects of high fat diet alone or in combination with liraglitude or sitagliptin treatments on frequency-domain of heart rate variability (SDNN, pNN5% and RMSSD). High-frequency (HF), low- frequency (LF) power spectra and the ratio between low-frequency to high-frequency (LF HF^-1 ratio) power spectra are shown. The following groups (n = 5 each) were examined: Control (CTRL), high fat diet (HFD), high fat diet plus liraglutide (HFD Liraglutide) and high fat diet plus sitagliptin (HFD Sitagliptin). Data are shown as mean ± SEM; <i>n</i> = 5–8. *<i>p<</i>0.05 vs. CTRL; **<i>p<</i>0.01 vs. CTRL; ^†<i>p<</i>0.05 vs. HFD; ^†††<i>p<</i>0.001 vs. HFD; ^‡<i>p<</i> 0.05 vs. HFD Liraglutide; ^‡‡<i>p<</i>0.01 vs. HFD Liraglutide and ^‡‡‡<i>p<</i>0.001 vs. HFD Liraglutide.</p