Perspectives on Interval Exercise Interventions for Non-Alcoholic Fatty Liver Disease. Medicines (Basel). 2019;6. [PMID: 31374827 PMCID: PMC6789719 DOI: 10.3390/medicines6030083]

Beneficial Effects of High-Intensity Interval Training and Dietary Changes Intervention on Hepatic Fat Accumulation in HFD-Induced Obese Rats

Lifestyle intervention encompassing nutrition and physical activity are effective strategies to prevent progressive lipid deposition in the liver. This study aimed to explore the effect of dietary change, and/or high-intensity interval training (HIIT) on hepatic lipid accumulation in high fat diet (HFD)-induced obese rats. We divided lean rats into lean control (LC) or HIIT groups (LH), and obese rats into obese normal chow diet (ND) control (ONC) or HIIT groups (ONH) and obese HFD control (OHC) or HIIT groups (OHH). We found that dietary or HIIT intervention significantly decreased body weight and the risk of dyslipidemia, prevented hepatic lipid accumulation. HIIT significantly improved mitochondrial fatty acid oxidation through upregulating mitochondrial enzyme activities, mitochondrial function and AMPK/PPARalpha/CPT1alpha pathway, as well as inhibiting hepatic de novo lipogenesis in obese HFD rats. These findings indicate that dietary alone or HIIT intervention powerfully improve intrahepatic storage of fat in diet induced obese rats. Keywords: Obesity, Exercise, Diet, Mitochondrial function, Lipid deposition.

High-intensity Interval Training for the Management of Nonalcoholic Steatohepatitis: Participant Experiences and Perspectives

Background and Aims

High-intensity interval training (HIIT) is a therapeutic option for people with nonalcoholic steatohepatitis (NASH). However, the perspectives and experiences of HIIT for people with NASH are unknown, limiting translation of research. We explored the experiences and perspectives of both professionally supervised and self-directed HIIT in people with NASH and evaluated participant-reported knowledge, barriers, and enablers to commencing and sustaining HIIT.

Methods

Twelve participants with NASH underwent 12 weeks of supervised HIIT (3 days/week, 4×4 minutes at 85-95% maximal heart rate, interspersed with 3 minutes active recovery), followed by 12-weeks of self-directed (unsupervised) HIIT. One-on-one, semistructured participant interviews were conducted by exercise staff prior to HIIT and following both supervised and self-directed HIIT to explore prior knowledge, barriers, enablers, and outcomes at each stage. Interviews were audio-recorded, transcribed, coded, and thematically analyzed by two independent researchers.

Results

Four dominant themes were identified: (1) no awareness of/experience with HIIT and ambivalence about exercise capabilities; (2) multiple medical and social barriers to commencing and continuing HIIT; (3) exercise specialist support was a highly valued enabler, and (4) HIIT was enjoyed and provided holistic benefits.

Conclusions

People with NASH may lack knowledge of and confidence for HIIT, and experience multiple complex barriers to commencing and continuing HIIT. Exercise specialist support is a key enabler to sustained engagement. These factors need to be addressed in future clinical programs to augment the uptake and long-term sustainability of HIIT by people with NASH so they can experience the range of related benefits.

Effect of aerobic training with silymarin consumption on glycemic indices and liver enzymes in men with type 2 diabetes

This study investigated the effect of eight weeks of aerobic training (AT) combined with silymarin (S)consumption on glycemic indices and liver enzymes in men with type 2 diabetes (T2D). In this clinical trial, 60 middle-aged male volunteers were randomly divided into 4 groups, including: (1) C + placebo(C) (2) AT + placebo (3), S and (4) AT + S. AT was performed for eight weeks, three sessions per week, each session for 20-45 minutes at an intensity of 60-85% of maximal heart rate reserve, and S receiving groups consumed 140 mg/kg S daily (in two servings). AT reduced glycemic indices and liver enzymes in men with T2D (p ≤ .05). S decreased blood glucose, insulin, HOMA-IR, AST, ALT and ALP in men with T2D (p ≤ .05). Exercise along with silymarin decreased blood glucose, insulin, HOMA-IR, AST, ALT and ALP. Also, reduction of AST and blood glucose in the AT + S group was more favourable than the effect of S alone (p ≤ .05). It seems that simultaneous AT and S has interactive effects on reducing glycemic indices and liver enzymes in men with T2D.

The effects of camelina sativa oil and high-intensity interval training on liver function and metabolic outcomes in male type 2 diabetic rats

Objectives

The purpose of this study was to evaluate the independent and combined effects of camelina sativa oil and high-intensity interval training (HIIT) on liver function, and metabolic outcomes in streptozotocin-induced diabetic rats.

Methods

Forty male Wistar rats were randomly assigned to five equal groups (8 per group): Normal control (NC), diabetic control (DC), diabetic + camelina sativa oil (300 mg/kg by oral gavage per day; D + CSO), diabetic + HIIT (running on a treadmill 5 days/week for 8 weeks; D + HIIT), diabetic + camelina sativa oil + HIIT (D + CSO +  HIIT).

Results

In all three intervention groups (D + CSO, D + HIIT, and D + CSO + HIIT) compared to the DC, hepatic TNF-α, MDA, and histopathology markers, decreased and hepatic PGC-1α, and PPAR-γ increased (p < 0.05). However, the effect of D + CSO was greater than D + HIIT alone. Hepatic TG decreased significantly in D + HIIT and D + CSO + HIIT compared to other groups (p < 0.001). Fasting plasma glucose in all three intervention groups (D + CSO, D + HIIT, and D + CSO + HIIT) and HOMA-IR in D + CSO and D + CSO + HIIT were decreased compared to DC (p < 0.001). Only hepatic TAC and fasting plasma insulin remained unaffected in the three diabetic groups (p < 0.001). Overall, D + CSO + HIIT had the largest effect on all outcomes.

Conclusions

At the doses and treatment duration used in the current study, combination of CSO and HIIT was beneficial for reducing liver function and metabolic outcomes other than CSO and HIIT alone.

Comparison of the effects of high-intensity interval training and moderate-intensity continuous training on indices of liver and muscle tissue in high-fat diet-induced male rats with non-alcoholic fatty liver disease

Background

Non-alcoholic fatty liver disease (NAFLD) is one of the most prevalent chronic liver diseases. It is shown that moderate to high physical activities can play a crucial role in improving this disease.

Aim

The purpose of this study was to explore the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on the levels of the myonectin in serum and tissue levels and fatty acid transport protein 4 (FATP4) in male rats with NAFLD.

Materials and methods

Thirty-three male rats were randomly divided into five groups: high-fat diet to confirm NAFLD induction (n = 5), normal diet sedentary (n = 7), high-fat diet sedentary (n = 7), high-fat diet with HIIT (n = 7), and high-fat diet with MCIT (n = 7). Induction of NAFLD was performed by feeding rats for 12 weeks with a high-fat diet containing 60% fat. The training protocols were performed in five sessions per week for 8 weeks. The HIIT group has performed 4 × 4 min interval running on a treadmill up to 80–95% maximal oxygen uptake (VO2max) and then recovered at 50–60% VO2max. The MICT protocol has performed up to 50–60% VO2max for 50 min. myonectin and FATP4 were also measured by the animal Elisa kit (Zellbio, Germany) with a sensitivity of 0.02 ng/L. Insulin resistance was evaluated by the insulin resistance homeostasis assessment index using the following formula (HOMA-IR): “fasting glucose (mg/dl) × fasting in insulin (mg/L) ÷ 405”. One-way ANOVA analysis of variance was utilized for statistical analyses and Tukey’s post hoc test at a significant level of p < 0.05.

Results

The 8-week intervention showed that both HIIT and MICT positively influenced the serum myonectin and FATP4 levels (p < 0.05). Moreover, there was a significant difference between the trained groups in tissue levels of the myonectin and serum levels of FATP4 (p < 0.05).

Conclusions

Altogether, both HIIT and MICT can lead to valuable adaptations and recovery of NAFLD in male rats.

NAFLD and Physical Exercise: Ready, Steady, Go!

Along with the increase in obesity and type 2 diabetes, the non-alcoholic fatty liver disease (NAFLD) incidence is escalating, thus becoming a leading cause of liver cirrhosis and a significant burden of liver-related outcomes. Since there is no pharmacotherapy available to address the NAFLD, the most effective solutions seem to be lifestyle changes centered on physical activity. Exercise could mediate its beneficial effects directly on the liver and indirectly via extrahepatic pathways, forming a dose-response relationship with NAFLD in terms of prevalence and disease severity. Health-enhancing physical activity (HEPA) levels are mainly needed to exert beneficial effects in obese subjects, while even a small amount of exercise can be beneficial for lean individuals to prevent NAFLD. This mini-review addresses three major points regarding physical activity and NAFLD: prevention, treatment, and extrahepatic benefits, offering recommendations on type and intensity of exercise in liver disease.

Clinical assessment and management of liver fibrosis in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is among the most frequent etiologies of cirrhosis worldwide, and it is associated with features of metabolic syndrome; the key factor influencing its prognosis is the progression of liver fibrosis. This review aimed to propose a practical and stepwise approach to the evaluation and management of liver fibrosis in patients with NAFLD, analyzing the currently available literature. In the assessment of NAFLD patients, it is important to identify clinical, genetic, and environmental determinants of fibrosis development and its progression. To properly detect fibrosis, it is important to take into account the available methods and their supporting scientific evidence to guide the approach and the sequential selection of the best available biochemical scores, followed by a complementary imaging study (transient elastography, magnetic resonance elastography or acoustic radiation force impulse) and finally a liver biopsy, when needed. To help with the selection of the most appropriate method a Fagan′s nomogram analysis is provided in this review, describing the diagnostic yield of each method and their post-test probability of detecting liver fibrosis. Finally, treatment should always include diet and exercise, as well as controlling the components of the metabolic syndrome, +/- vitamin E, considering the presence of sleep apnea, and when available, allocate those patients with advanced fibrosis or high risk of progression into clinical trials. The final end of this approach should be to establish an opportune diagnosis and treatment of liver fibrosis in patients with NAFLD, aiming to decrease/stop its progression and improve their prognosis.