Hepatic gene expression in mouse models of non-alcoholic fatty liver disease after acute exercise

Physical Activity and Nonalcoholic Fatty Liver Disease: A Roundtable Statement from the American College of Sports Medicine

ABSTRACT

Although physical activity (PA) is crucial in the prevention and clinical management of nonalcoholic fatty liver disease, most individuals with this chronic disease are inactive and do not achieve recommended amounts of PA. There is a robust and consistent body of evidence highlighting the benefit of participating in regular PA, including a reduction in liver fat and improvement in body composition, cardiorespiratory fitness, vascular biology, and health-related quality of life. Importantly, the benefits of regular PA can be seen without clinically significant weight loss. At least 150 min of moderate or 75 min of vigorous intensity PA are recommended weekly for all patients with nonalcoholic fatty liver disease, including those with compensated cirrhosis. If a formal exercise training program is prescribed, aerobic exercise with the addition of resistance training is preferred. In this roundtable document, the benefits of PA are discussed, along with recommendations for 1) PA assessment and screening; 2) how best to advise, counsel, and prescribe regular PA; and 3) when to refer to an exercise specialist.

Alterations in bile acid metabolizing gut microbiota and specific bile acid genes as a precision medicine to subclassify NAFLD

Multiple mechanisms for the gut microbiome contributing to the pathogenesis of nonalcoholic fatty liver disease (NAFLD) have been implicated. Here, we aim to investigate the contribution and potential application for altered bile acids (BA) metabolizing microbes in NAFLD by post hoc analysis of whole metagenome sequencing (WMS) data. The discovery cohort consisted of 86 well-characterized patients with biopsy-proven NAFLD and 38 healthy controls. Assembly-based analysis was performed to identify BA-metabolizing microbes. Statistical tests, feature selection, and microbial coabundance analysis were integrated to identify microbial alterations and markers in NAFLD. An independent validation cohort was subjected to similar analyses. NAFLD microbiota exhibited decreased diversity and microbial associations. We established a classifier model with 53 differential species exhibiting a robust diagnostic accuracy [area under the receiver-operator curve (AUC) = 0.97] for detecting NAFLD. Next, eight important differential pathway markers including secondary BA biosynthesis were identified. Specifically, increased abundance of 7α-hydroxysteroid dehydrogenase (7α-HSDH), 3α-hydroxysteroid dehydrogenase (baiA), and bile acid-coenzyme A ligase (baiB) was detected in NAFLD. Furthermore, 10 of 50 BA-metabolizing metagenome-assembled genomes (MAGs) from Bacteroides ovatus and Eubacterium biforme were dominant in NAFLD and interplayed as a synergetic ecological guild. Importantly, two subtypes of patients with NAFLD were observed according to secondary BA metabolism potentials. Elevated capability for secondary BA biosynthesis was also observed in the validation cohort. These bacterial BA-metabolizing genes and microbes identified in this study may serve as disease markers. Microbial differences in BA-metabolism and strain-specific differences among patients highlight the potential for precision medicine in NAFLD treatment.

Bioactive dipeptide from potato protein hydrolysate combined with swimming exercise prevents high fat diet induced hepatocyte apoptosis by activating PI3K/Akt in SAMP8 mouse

Obesity in aged population have surges the occurrence of various metabolic disorders including Nonalcoholic fatty liver disease (NAFLD). Apoptosis in the liver is one of the causative factors for NAFLD-induced liver damage. Plants derived bioactive peptides have been shown as an alternative treatment approach for the treating NAFLD due to its less toxicity. Moderate exercise has been reported to improve cellular physiological function prevent age associated metabolic disorders. In the present study, we evaluate the effects of bioactive dipeptide (IF) derived from alcalase potato-protein hydrolysates and swimming exercise in preventing High Fat Diet (HFD)-induced liver damage in senescence accelerated mouse-prone 8 (SAMP8) mice model. Mouse were fed with HFD for 6 weeks followed by oral IF administration or swimming exercise and both for 8 weeks. HFD induces significant structural changes in liver of HFD fed SAMP8 mouse. Both IF administration and exercise prevent the structural abnormalities induced by HFD, however, combined IF treatment and exercise offer better protection. Combined IF treatment and exercise activate PI3K/Akt cell survival protein and effectively inhibit Fas-FADD-induced apoptosis in HFD fed aged mouse. Oral supplementation of bioactive peptide IF combined with moderate swimming exercise effectively alleviate HFD-induced hepatic injury in aged mice.

High-Fat Diet and Age-Dependent Effects of IgA-Bearing Cell Populations in the Small Intestinal Lamina Propria in Mice

Several studies highlighted that obesity and diabetes reduce immune function. However, changes in the distribution of immunoglobins (Igs), including immunoglobulin-A (IgA), that have an important function in mucosal immunity in the intestinal tract, are unclear. This study aimed to investigate the impaired immune functions in the context of a diet-induced obese murine model via the assessment of the Igs in the intestinal villi. We used mice fed a high-fat diet (HFD) from four to 12 or 20 weeks of age. The distributions of IgA, IgM, and IgG1 were observed by immunohistochemistry. Interestingly, we observed that IgA was immunolocalized in many cells of the lamina propria and that immunopositive cells increased in mice aged 12 to 20 weeks. Notably, mice fed HFD showed a reduced number of IgA-immunopositive cells in the intestinal villi compared to those fed standard chow. Of note, the levels of IgM and IgG1 were also reduced in HFD fed mice. These results provide insights into the impaired mucosal immune function arising from diet-induced obesity and type 2 diabetes.

Effects of Long-Term Exercise on Liver Cyst in Polycystic Liver Disease Model Rats

BACKGROUND

Polycystic liver disease (PLD) is a hereditary liver disease with progressive enlargement of fluid-filled liver cysts, which causes abdominal discomfort and worsens quality of life. Long-term exercise has beneficial effects in various organs, but the effects of long-term exercise on PLD are unclear. Therefore, the aim of this study was to investigate whether long-term exercise inhibits liver cyst formation and fibrosis.

METHODS

Polycystic kidney (PCK) rats, a model of PLD, were randomly divided into a sedentary group and a long-term exercise group, which underwent treadmill running for 12 wk (28 m·min, 60 min·d, 5 d·wk). Sprague-Dawley (SD) rats were set as a control group. After 12 wk, exercise capacity, histology, and signaling cascades of PLD were examined.

RESULTS

Compared with control SD rats, PCK rats showed a low exercise capacity before exercise protocol. After 12 wk, the exercise improved the exercise capacity and ameliorated liver cyst formation and fibrosis. The exercise significantly decreased the number of Ki-67-positive cells; the expression of cystic fibrosis transmembrane conductance regulator, aquaporin 1, transforming growth factor β, and type 1 collagen; and the phosphorylation of extracellular signal-regulated kinase, mammalian target of rapamycin and S6. It also increased the phosphorylation of AMP-activated protein kinase in the liver of PCK rats.

CONCLUSIONS

The present results indicated that long-term moderate-intensity exercise ameliorates liver cyst formation and fibrosis with the inhibition of signaling cascades responsible for cellular proliferation and fibrosis in PCK rats.

A novel dipeptide from potato protein hydrolysate augments the effects of exercise training against high-fat diet-induced damages in senescence-accelerated mouse-prone 8 by boosting pAMPK / SIRT1/ PGC-1α/ pFOXO3 pathway

The pathological effects of obesity are often severe in aging condition. Although exercise training is found to be advantageous, the intensity of exercise performed is limited in aging condition. Therefore in this study we assessed the effect of a combined treatment regimen with a short-peptide IF isolated from alcalase potato-protein hydrolysates and a moderate exercise training for 15 weeks in a 6 month old HFD induced obese senescence accelerated mouse-prone 8 (SAMP8) mice model. Animals were divided into 6 groups (n=6) (C:Control+BSA); (HF:HFD+BSA); (EX:Control+ BSA+Exercise); (HF+IF:HFD+ IF); (HF+EX:HFD+Exercise); (HF+EX+IF:HFD+Exercise+IF). A moderate incremental swimming exercise training was provided for 6 weeks and after 3 weeks of exercise, IF was orally administered (1 mg/kg body Weight). The results show that combined administration of IF and exercise provides a better protection to aging animals by reducing body weight and regulated tissue damage. IF intake and exercise training provided protection against cardiac hypertrophy and maintains the tissue homeostasis in the heart and liver sections. Interestingly, IF and exercise training showed an effective upregulation in pAMPK/ SIRT1/ PGC-1α/ pFOXO3 mechanism of cellular longevity. Therefore, exercise training with IF intake is a possible strategy for anti-obesity benefits and superior cardiac and hepatic protection in aging condition.