Efficacy and mechanism of intermittent fasting in metabolic associated fatty liver disease based on ultraperformance liquid chromatography-tandem mass spectrometry

[Risk analysis of serum chemical residues for metabolic associated fatty liver disease based on exposome-lipidome wide association study]

Metabolic associated fatty liver disease (MAFLD) is a common liver disease with a prevalence of up to 25%; it not only adversely affects human health but also aggravates the economic burden of society. An increasing number of studies have suggested that the occurrence of chronic noncommunicable diseases is affected by both environmental exposures and genetic factors. Research has also shown that environmental pollution may increase the risk of MAFLD and promote its occurrence and development. However, the relationship between these concepts, as well as the underlying exposure effects and mechanism, remains incompletely understood. Lipidomics, a branch of metabolomics that studies lipid disorders, can help researchers investigate abnormal lipid metabolites in various disease states. Lipidome-exposome wide association studies are a promising paradigm for investigating the health effects of cumulative environmental exposures on biological responses, and could provide new ideas for determining the associations between metabolic and lipid changes and disease risk caused by chemical-pollutant exposure. Hence, in this study, targeted exposomics and nontargeted lipidomics studies based on ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) were used to characterize exogenous chemical pollutants and endogenous lipid metabolites in the sera of patients with MAFLD and healthy subjects. The results demonstrated that fipronil sulfone, malathion dicarboxylic acid, and monocyclohexyl phthalate may be positively associated with the disease risk of patients diagnosed as simple fatty liver disease (hereafter referred to as MAFLD(0)). Moreover, fipronil sulfone, acesulfame potassium, perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluoroundecanoic acid (PFUnDA), 4-hydroxybenzophenone, and 3,5-di-tert-butyl-4-hydroxybenzoic acid (DBPOB) may be positively associated with the disease risk of patients diagnosed as fatty liver complicated by single or multiple metabolic disorders. Association analysis was carried out to explore the lipid metabolites induced by chemical residues. Triglyceride (TG) and diglyceride (DG) were significantly increased in MAFLD and MAFLD(0). The numbers of carbons of significantly changed DGs and TGs were mainly in the ranges of 32-40 and 35-60, respectively, and both were mainly characterized by changes in polyunsaturated lipids. Most of the lipid-effect markers were positively correlated with chemical residues and associated with increased disease risk. Our research provides a scientific basis for studies on the association and mechanism between serum chemical-pollutant residues and disease outcomes.

Integrating network analysis and pharmacokinetics to investigate the mechanisms of Danzhi Tiaozhi Decoction in metabolic-associated fatty liver disease (MAFLD)

ETHNOPHARMACOLOGICAL RELEVANCE

Based on ancient classics, Danzhi Tiaozhi Decoction has been successfully used to treat nonalcoholic fatty liver disease for decades. However, its therapeutic mechanisms remain unclear.

AIM OF THE STUDY

This study aimed to investigate the effects of Danzhi Tiaozhi Decoction (DZTZD) on metabolic-associated fatty liver disease (MAFLD).

MATERIALS AND METHODS

First, we identified the active ingredients of DZTZD and their potential targets in the Traditional Chinese Medicine System Pharmacology database. Using the overlapped genes, we selected the key MAFLD-associated genes, then conducted GO and KEGG pathway enrichment analyses. Furthermore, DZTZD was administered orally to rats, and their serum and liver tissues were examined for absorbed compounds using pharmacochemistry. UPLC-Q-Exactive Orbitrap/MS was used to determine the main compounds. Then, we validated the binding association of the key targets with their active compounds with AutoDock Tools and other software. Finally, the predicted hub targets were experimentally validated.

RESULTS

We found 254 active compounds in DZTZD corresponding to 208 targets. Sixteen key genes were identified, and the enrichment analysis revealed multiple signaling pathways, including the AGE-RAGE pathway in diabetic complications and the lipid and atherosclerosis signaling pathway. Next, 160 absorbed components and metabolites were characterized in vivo, and 53 absorbed components and metabolites were characterized in liver tissue. Thirteen parent compounds were identified, including coptisine, quercetin, luteolin, and aloe-emodin. The molecular docking data demonstrated the strongest binding between the active compounds and the core proteins. Moreover, the animal experiments showed that DZTZD decreased body weight, liver weight, lipid accumulation, and ALT, AST, CRP, FFA, IL-6, PEPCK, G6P, TG, TC, and LDL-c serum levels, and increased serum HDL-c levels compared to high-fat induced rats. Besides, the RT-PCR and Western blot showed that DZTZD inhibited the SREBP1c and FAS and increased hyperlipidemia-induced CPT-1A levels. In the high-fat group, JNK phosphorylation increased, and AKT protein phosphorylation decreased, while DZTZD reversed these effects.

CONCLUSION

Based on the pharmacological network analysis, pharmacochemistry, and experimental validation, DZTZD can potentially improve MAFLD via the JNK/AKT pathway.

Exercise Equals the Mobilization of Visceral versus Subcutaneous Adipose Fatty Acid Molecules in Fasted Rats Associated with the Modulation of the AMPK/ATGL/HSL Axis

Combining exercise with fasting is known to boost fat mass-loss, but detailed analysis on the consequential mobilization of visceral and subcutaneous WAT-derived fatty acids has not been performed. In this study, a subset of fasted male rats (66 h) was submitted to daily bouts of mild exercise. Subsequently, by using gas chromatography-flame ionization detection, the content of 22 fatty acids (FA) in visceral (v) versus subcutaneous (sc) white adipose tissue (WAT) depots was compared to those found in response to the separate events. Findings were related to those obtained in serum and liver samples, the latter taking up FA to increase gluconeogenesis and ketogenesis. Each separate intervention reduced scWAT FA content, associated with increased levels of adipose triglyceride lipase (ATGL) protein despite unaltered AMP-activated protein kinase (AMPK) Thr172 phosphorylation, known to induce ATGL expression. The mobility of FAs from vWAT during fasting was absent with the exception of the MUFA 16:1 n-7 and only induced by combining fasting with exercise which was accompanied with reduced hormone sensitive lipase (HSL) Ser563 and increased Ser565 phosphorylation, whereas ATGL protein levels were elevated during fasting in association with the persistently increased phosphorylation of AMPK at Thr172 both during fasting and in response to the combined intervention. As expected, liver FA content increased during fasting, and was not further affected by exercise, despite additional FA release from vWAT in this condition, underlining increased hepatic FA metabolism. Both fasting and its combination with exercise showed preferential hepatic metabolism of the prominent saturated FAs C:16 and C:18 compared to the unsaturated FAs 18:1 n-9 and 18:2 n-6:1. In conclusion, depot-specific differences in WAT fatty acid molecule release during fasting, irrelevant to their degree of saturation or chain length, are mitigated when combined with exercise, to provide fuel to surrounding organs such as the liver which is correlated with increased ATGL/ HSL ratios, involving AMPK only in vWAT.