The effects of high-intensity interval training on reverse cholesterol transport elements: A way of cardiovascular protection against atherosclerosis

Hepatic Lipid Metabolism Disorder and Atherosclerosis

Lipid metabolism disorder plays a fundamental role in the pathogenesis of atherosclerosis. As the largest metabolic organ of the human body, liver has a key role in lipid metabolism by influencing fat production, fat decomposition, and the intake and secretion of serum lipoproteins. Numerous clinical and experimental studies have indicated that the dysfunction of hepatic lipid metabolism is closely tied to the onset of atherosclerosis. However, the identity and functional role of hepatic lipid metabolism responsible for these associations remain unknown. This review presented that cholesterol synthesis, cholesterol transport, and the metabolism of triglyceride, lipoproteins, and fatty acids are all associated with hepatic lipid metabolism and atherosclerosis. Moreover, we also discussed the roles of gut microbiota, inflammatory response, and oxidative stress in the pathological association between hepatic lipid metabolism and atherosclerosis. These significant evidences support strongly that hepatic lipid metabolism disorders may increase the risk of atherosclerosis.

Isolated obesity resistance condition or associated with aerobic exercise training does not promote cardiac impairment

Mechanisms involved in cardiac function and calcium (Ca²⁺) handling in obese-resistant (OR) rats are still poorly determined. We tested the hypothesis that unsaturated high-fat diet (HFD) promotes myocardial dysfunction in OR rats, which it is related to Ca²⁺ handling. In addition, we questioned whether exercise training (ET) becomes a therapeutic strategy. Male Wistar rats (n=80) were randomized to standard or HFD diets for 20 weeks. The rats were redistributed for the absence or presence of ET and OR: control (C; n=12), control + ET (CET; n=14), obese-resistant (OR; n=9), and obese-resistant + ET (ORET; n=10). Trained rats were subjected to aerobic training protocol with progressive intensity (55-70% of the maximum running speed) and duration (15 to 60 min/day) for 12 weeks. Nutritional, metabolic, and cardiovascular parameters were determined. Cardiac function and Ca²⁺ handling tests were performed in isolated left ventricle (LV) papillary muscle. OR rats showed cardiac atrophy with reduced collagen levels, but there was myocardial dysfunction. ET was efficient in improving most parameters of body composition. However, the mechanical properties and Ca²⁺ handling from isolated papillary muscle were similar among groups. Aerobic ET does not promote morphological and cardiac functional adaptation under the condition of OR.

Effects of resistance training and nigella sativa on type 2 diabetes: implications for metabolic markers, low-grade inflammation and liver enzyme production

CONTEXT

Proper nutrition and exercise are effective strategies to improve overall metabolic health in diabetic patients.

OBJECTIVE

This study evaluated the effects of Nigella sativa (NS) supplementation during resistance training (RT) on some biochemical variables in type 2 diabetes patients.

METHODS

Forty patients were assigned to groups: RT + NS (RN), NS, RT + placebo (RP), and control (CO). RT was performed and NS was consumed for 8 weeks. Blood samples were collected at rest immediately before and after the 8 week intervention.

RESULTS

RT or NS by themselves reduced HOMA-IR, insulin, glucose, TG, TC, LDL, ESR, CRP, AST, ALT and ALP, and increased HDL and HOMA-S. The combination of RT and NS, rather than each intervention alone, had significant effects on reduction of HOMA-IR, insulin, ESR and CRP as well as increases in HDL, HOMA-β/S.

CONCLUSION

RT combined with NS is sometimes a better strategy compared to single interventions for improving diabetes related biomarkers in type 2 diabetic patients.

Liver X Receptor α in Sciatic Nerve Exerts an Alleviating Effect on Neuropathic Pain Behaviors Induced by Crush Injury

Peripheral nerve injury often leads to neuropathic pain. In the present study, we assessed the role of liver x receptor alpha (LXRα), an oxysterol regulated nuclear transcription factor that promotes reverse cholesterol transport and alternative (M2) macrophage activation, in the development of neuropathic pain. We found that compared to WT mice, in LXRα knockout mice the development of mechanical allodynia following sciatic nerve crush was accelerated and the duration was prolonged. Furthermore, the expression of M1-like macrophage marker iNOS and M1-like macrophages inducer hydrogen peroxide (H2O2) was increased, whereas expression of M2 macrophage marker arginase-1 (Arg-1) and interleukin-10 (IL-10) was reduced in the sciatic nerve of LXRα knockout mice. Moreover, peri-sciatic administration of LXRs agonist GW3965, immediately after the nerve crush, into wild type mice, suppressed the mechanical allodynia induced by crush injury. GW3965 also suppressed the expression of iNOS and production of H2O2 in the injured nerve and enhanced the expression of IL-10 and Arg-1. Importantly, peri-sciatic administration of IL-10 neutralization antibody prevented the alleviating effect of GW3965 on mechanical allodynia. Altogether, these results indicates that the lack of LXRα in the sciatic nerve results in an augmented inflammatory profile of macrophages, which ultimately speed up the development of neuropathic pain and dampen its recovery following nerve injury. Activation of LXRα by its agonist might rebalance the neuroprotective and neurotoxic macrophage phenotypes, and thus alleviate the neuropathic pain behavior.

Effect of moderate-intensity exercise training on GDNF signaling pathway in testicles of rats after experimental diabetes type 1 induction

AIMS

The spermatogenesis failure is reported as the main complication for diabetes and the moderate-intensity exercise (EX) is shown to ameliorate the diabetes-induced impairments both at spermatogenesis and sperm levels. Thus, the current study was done to investigate the possible effect of EX in the sole and simultaneous form with insulin on the network between Sertoli and spermatogonial stem cells (SSCs) by focusing on niche factor Glial cell-derived neurotrophic factor (GDNF).

METHODS

For this purpose, 30 mature male Wistar rats were divided into control and experimental type 1 diabetes (T1D)-induced groups. Then the T1D-induced animals were subdivided to sedentary T1D-induced (ST1D), EX + T1D, insulin (INS) + T1D and EX + INS + T1D groups. The general histological changes of testicles, mRNA and protein contents of GDNF and its special receptors gfrα1 and c-RET were evaluated and compared between groups.

RESULTS

EX in the sole and simultaneous form with INS significantly (p < 0.05) diminished the T1D-induced histological damages, amplified the GDNF expression, and enhanced the gfrα1 and c-RET mRNA and protein contents compared to ST1D group.

CONCLUSION

In conclusion, the EX in the sole form promotes spermatogenesis by up-regulating the GDNF signaling system. Moreover, EX remarkably amplifies the insulin-induced ameliorative effect on spermatogenesis.

Taurine with combined aerobic and resistance exercise training alleviates myocardium apoptosis in STZ-induced diabetes rats via Akt signaling pathway

AIM

The aim of this study was considering the effects of taurine supplementation with combined aerobic and resistance training (CARE) on myocardial apoptosis and Protein Kinase B (akt) level changes in diabetic rat.

MAIN METHODS

Forty male Wistar rats were randomly divided in to 5 groups of 8 animals in each: 1) control, 2) Diabetes Mellitus (DM), 3) DM with taurine supplementation (DM/T), 4) DM with CARE (DM/CARE), and 5) DM with combination of taurine and CARE (DM/T/CARE). DM was induced by injection of streptozotocin (STZ) and nicotine amid (NA) for 2, 3, 4 and 5 groups. Supplement groups received taurine in gavage, 100 mg/kg of body weight, 6 day per weeks, 8 weeks. CARE was performed at maximal speed and 1RM (40-60% of maximum for both).

KEY FINDINGS

The results of this study showed that DM significantly increased blood glucose and caspase 3, caspase 9 expressions and apoptosis cells in heart tissue and reduced Akt expression (p < 0.001). However, taurine and CARE interventions significantly decreased apoptosis markers (caspase 3 and caspase 9) and significantly increased Akt in heart of diabetic rats compare to DM groups (p < 0.05). The highest improvement observed in DM/T/CARE group (p < 0.05).

SIGNIFICANCE

Based on these results, it seems that the use of taurine with combined aerobic and exercise training minimize the cardiac damage caused by diabetes (especially apoptosis) trough increasing protein kinase Akt expression. This could improve cardiac remodeling after diabetes. However, more research is needed, especially on the human samples.

The expression change of glial fibrillary acidic protein and tyrosine hydroxylase in substantia nigra of the Wistar rats exposed to chlorpyrifos: a novel environmental risk factor for Parkinson's disease

Chlorpyrifos (CPF) is one of the most abundant and widely used pesticides in the world. CPF has detrimental effects on brain tissue, so it is possible to generate some neurodegenerative diseases. The aim of this study was to evaluate the effect of CPF on inducing the Parkinson's disease affecting on central nervous system. 6 to 8-week-old animals were categorized into three groups. The first group was normal control which the animals did not received any treatment, while in the second group, CPF were injected (CPF; 5 mg/kg BW for 30 days intraperitoneally) and the sham group as the third group received DMSO. At the end of the CPF treatment, malondialdehyde (MDA) and superoxide dismutase (SOD) levels were measured in the brain tissues of rats. Proportion of neurons was analyzed by crystal violet assays and tunnel assay to detect apoptotic cells. Finally, the expression of GFAP and TH was investigated in the brain of animals. The results witnessed an increase in MDA and a decrease in SOD (P < 0.05) after the CPF treating. Moreover, results indicated that the proportion of neurons decreased in the second group vs. normal and sham groups significantly (P < 0.001). Additionally, in substantia nigra, the expression of GFAP had a significant increase and the TH had a remarkable decrease in CPF injected group in comparison to two other groups (P < 0.001). Furthermore, the numbers of apoptosis cells reduced in substantia nigra (P < 0.001) after the 30-day period of CPF injections. These results demonstrated that repeated exposure to CPF can induce PD via apoptotic cell death, histopathological disruption. It also altered the expression of dopaminergic neuron and changes the levels of oxidant and antioxidant enzymes in substantia nigra region which triggers PD. Hence, the CPF can be introduced as a risk factor for PD.

Effects of high intensity interval training (up & downward running) with BCAA/nano chitosan on Foxo3 and SMAD soleus muscles of aging rat

AIMS

The aim of this study was investigate the effects of 8 weeks of high intensity interval training (HIIT, up & downward running) with BCAA/nano chitosan on Foxo3 and SMAD soleus muscles of aging rats.

MAIN METHODS

In this experimental study thirty male rats were randomly divided into six groups of control, BCAA with Nano chitosan (Supplement, (Sup)), upslope running, downslope running, upslope running+Sup, and downslope running+Sup that each groups consist of 6 rats. The exercise training was performed HIIT 8 weeks 3 session per weeks with incrementally intensity 12 to 52 m/m in 7sets (Slop 0 to 15^o) during 8 weeks. BCAA coated with chitosan nanoparticles (84 mg/kg) and gavage to supplementation groups, 3 days per weeks for eight weeks. The animals were feed with standard rat chow (Normal diet, 2.87 kcal/g, 15% of energy from fat). At the end of protocol the rat was sacrifice and soleus muscle was fix and frieze for IHC with H&E and gene expression analysis.

KEY FINDINGS

The results of this study showed that Foxo3 gene expression in the Upslope running + Sup and Downslope running + Sup groups showed a significant decrease (p ≤ 0.05) compared to the control group. The mRNA of Smad also showed that only the Upslope running + Sup group had a significant decrease compared to the control group (p ≤ 0.05).

SIGNIFICANCE

It seems that, BCAA/nano chitosan supplementation along with exercise training in a variety of ways (Up & down slope running) can control the damage caused by Foxo3 and Smad transcription factors. That, control of these factors can minimize age-related atrophy.

The effects of exercise training on lipid metabolism and coronary heart disease

Blood lipoproteins are formed by various amounts of cholesterol (C), triglycerides (TGs), phospholipids, and apolipoproteins (Apos). ApoA1 is the major structural protein of high-density lipoprotein (HDL), accounting for ~70% of HDL protein, and mediates many of the antiatherogenic functions of HDL. Conversely, ApoB is the predominant low-density lipoprotein (LDL) Apo and is an indicator of circulating LDL, associated with higher coronary heart disease (CHD) risk. Thus, the ratio of ApoB to ApoA1 (ApoB/ApoA1) is used as a surrogate marker of the risk of CHD related to lipoproteins. Elevated or abnormal levels of lipids and/or lipoproteins in the blood are a significant CHD risk factor, and several studies support the idea that aerobic exercise decreases CHD risk by partially lowering serum TG and LDL-cholesterol (LDL-C) levels and increasing HDL-C levels. Exercise also exerts an effect on HDL-C maturation and composition and on reverse C transport from peripheral cells to the liver to favor its catabolism and excretion. This process prevents atherosclerosis, and several studies showed that exercise training increases heart lipid metabolism and protects against cardiovascular disease. In these and other ways, it more and more appears that regular exercise, nutrition, and strategies to modulate lipid profile should be viewed as an integrated whole. The purpose of this review is to assess the effects of endurance training on the nontraditional lipid biomarkers, including ApoB, ApoA1, and ApoB/ApoA1, in CHD risk.

The interaction between ABCA1 polymorphism and physical activity on the HDL-cholesterol levels in a Japanese population

Few studies have investigated the interactions between HDL-C-related SNPs identified by genome-wide association (GWA) study and physical activity (PA) on HDL-C. First, we conducted a sex-stratified GWA study in a discovery sample (2,231 men and 2,431 women) and replication sample (2,599 men and 3,109 women) to identify SNPs influencing log-transformed HDL-C in Japanese participants in the baseline survey of the Japan Multi-Institutional Collaborative Cohort Study. We also replicated previously reported HDL-C-related SNPs in a combined (discovery plus replication) sample (4,830 men and 5,540 women). We then analyzed the interactions of the HDL-C-related SNPs with PA on HDL-C. The sex-stratified GWA analyses identified 11 and 10 HDL-C-related SNPs in men and women as targets for an interaction analysis. Among these, only one interaction of ABCA1 rs1883025 with PA was statistically significant in men, after Bonferroni correction [P-interaction = 0.001 (α = 0.05/21 = 0.002)]. The per-major-allele (C allele) increase in log-transformed HDL-C was lost in men with low PA (β = 0.008) compared with those with medium (β = 0.032) or high PA (β = 0.034). These findings suggest that the benefit of carrying a C allele of ABCA1 rs1883025 on enhancing HDL-C may be attenuated in inactive men.

High-intensity interval training has a greater effect on reverse cholesterol transport elements compared with moderate-intensity continuous training in obese male rats

OBJECTIVES

The present study compares the effect of high-intensity interval training (HIIT; 18 min) and moderate-intensity continuous training (MIT; 1 h) on reverse cholesterol transport (RCT) elements in obese subjects.

METHODS

Thirty adult male rats were induced high-fat diet (HFD) for 12 weeks. After four weeks, the rats were randomly divided into three groups while simultaneously continuing the HFD for the remaining eight weeks. Group specificities were HFD-control, HFD-MIT and HFD-HIIT. The rats were sacrificed 48 h after the last training session and the samples were collected. Analysis of variance and Pearson's correlation test were used for the statistical analyses (significance level: p ≤ 0.05).

RESULTS

The results showed that both HIIT and MIT improved heart ABCA1, ABCG1, ABCG4, ABCG5, ABCG8, LXR-α and PPARγ gene expression as well as plasma Apo A1, LCAT, lipids and lipoproteins (p ≤ 0.05). Moreover, higher cardiac ABCA1, ABCG1, ABCG4, ABCG5, ABCG8 and PPARγ expression and plasma high-density lipoprotein cholesterol (p ≤ 0.05) concentrations were found in the HFD-HIIT group compared with the HFD-MIT group.

CONCLUSION

HIIT may have more cardioprotective effects than MIT against atherosclerosis, along with saving time, as supported by the changes observed in the main factors involved in the RCT process.

Effects of exercise on reverse cholesterol transport: A systemized narrative review of animal studies

AIMS

Reverse Cholesterol Transport (RCTr) is the mechanism by which excess cholesterol from peripheral tissues is transported to the liver for hepatobiliary excretion, thereby inhibiting foam cell formation and the development of atherosclerosis. Exercise affects RCTr, by influencing high-density lipoprotein cholesterol (HDL) through remodeling and by promoting hepatobiliary sterol excretion. The objectives of this systematized review of animal studies is to summarize the literature and provide an overview of the effects of chronic exercise (at least two weeks) on apolipoproteins (Apo A-I, Apo-E), Paraoxonase-1 (PON1), ATP-binding cassette transporters (ABCA1, ABCG1, ABCG4, ABCG5, ABCG8), scavenger receptor class B type I (SR-BI), cholesteryl ester transfer protein (CETP), low-density lipoprotein receptor (LDLr) and cholesterol 7 alpha-hydroxylase (CYP7A1) and Niemann-Pick C1-like 1 (NPC1L1).

MATERIALS AND METHODS

Three electronic databases (PubMed, Science Direct and Google Scholar) were searched for eligible studies conducted from the earliest available date to August 2018.

KEY FINDINGS

Most of studies investigate the effects of low to moderate intensity aerobic training on RCTr elements. The majority were on exercised rats undertaking moderate intensity aerobic training.

SIGNIFICANCE

This review highlights that moderate intensity and longer-term training has a greater effect on RCTr elements than low intensity training. There a few studies examining high intensity training which warrants further investigation.