Effect of Betaine Supplementation on Liver Tissue and Ultrastructural Changes in Methionine-Choline-Deficient Diet-Induced NAFLD

Differences in Fatty Acid Metabolism between MCDD and HFD Induced Metabolic Dysfunction-associated Fatty Liver Disease Model Mice

BACKGROUND

The global incidence of metabolic dysfunction-associated fatty liver disease (MAFLD) is increasing annually, which has become a major public-health concern. MAFLD is typically associated with obesity, hyperlipemia, or metabolic syndrome. Dietary induction is one of the most common methods for preparing animal models of MAFLD. However, there are phenotypic differences between methionine-choline-deficient diet (MCDD) and high fat diet (HFD) models.

METHODS

To explore the differences in hepatic fatty acid metabolism between MCDD and HFD induced MAFLD, we analyzed serum and liver tissue from the two MAFLD models.

RESULTS

We found that liver fat accumulation and liver function damage were common pathological features in both MAFLD models. Furthermore, in the MCDD model, the expression of hepatic fatty acid transport proteins increased, while the expression of hepatic fatty acid efflux proteins and mRNA decreased, along with a decrease in blood lipid levels. In the HFD model, the expression of hepatic fatty acid uptake proteins, efflux proteins and efflux mRNA increased, along with an increase in blood lipid levels.

CONCLUSION

Impaired fatty acid oxidation and increased hepatic fatty acid uptake play key roles in the pathogenesis of the two MAFLD models. The inverse changes in de novo lipogenesis and fatty acid efflux may represent an important pathological mechanism that leads to the phenotypic differences between the MCDD and HFD models.

Betaine regulates the gut-liver axis: a therapeutic approach for chronic liver diseases

Chronic liver disease is defined by persistent harm to the liver that might result in decreased liver function. The two prevalent chronic liver diseases are alcohol-associated liver disease (ALD) and metabolic dysfunction-associated steatotic liver disease (MASLD). There is ample evidence that the pathogenesis of these two chronic liver diseases is closely linked to gastrointestinal dysfunctions that alters the gut-liver crosstalk. These alterations are mediated through the imbalances in the gut microbiota composition/function that combined with disruption in the gut barrier integrity allows for harmful gut microbes and their toxins to enter the portal circulation and reach the liver to elicit an inflammatory response. This leads to further recruitment of systemic inflammatory cells, such as neutrophils, T-cells, and monocytes into the liver, which perpetuate additional inflammation and the development of progressive liver damage. Many therapeutic modalities, currently used to prevent, attenuate, or treat chronic liver diseases are aimed at modulating gut dysbiosis and improving intestinal barrier function. Betaine is a choline-derived metabolite and a methyl group donor with antioxidant, anti-inflammatory and osmoprotectant properties. Studies have shown that low betaine levels are associated with higher levels of organ damage. There have been several publications demonstrating the role of betaine supplementation in preventing the development of ALD and MASLD. This review explores the protective effects of betaine through its role as a methyl donor and its capacity to regulate the protective gut microbiota and maintain intestinal barrier integrity to prevent the development of these chronic liver diseases. Further studies are needed to enhance our understanding of its therapeutic potential that could pave the way for targeted interventions in the management of not only chronic liver diseases, but other inflammatory bowel diseases or systemic inflammatory conditions.

Integrated metabolomics and transcriptomics reveal the potential of hydroxy-alpha-sanshool in alleviating insulin resistance

Hydroxy-alpha-sanshool (HAS) has attracted attention because of its various biological activities, such as hypoglycemic, hypolipidemic, and antioxidant activities. In this study, we investigated the effects of HAS on insulin resistance (IR) and its mechanism. HAS reduced fasting blood glucose (FBG), promoted insulin (INS) secretion, significantly decreased levels of interleukin (IL)-1, IL-6, tumor necrosis factor (TNF)-α and monocyte chemoattractant protein-1 (MCP-1), and increased the IL-2 level in serum of IR model mice. HAS regulated the mRNA levels of protein kinase B (Akt), B-cell lymphoma extra-large (Bcl-xL), stearoyl-CoA desaturase-1 (SCD1), nuclear factor kappa B (NF-κB), and eukaryotic translation initiation factor 4E (eIF4E). Additionally, differentially abundant metabolites in IR model mice treated with HAS were involved in these signaling pathways including prion disease, choline metabolism in cancer, regulation of lipolysis in adipocytes and the pentose phosphate pathway and positively regulated betaine abundance. In conclusion, HAS activated the phosphatidylinositol-3 kinase (PI3K)/Akt insulin and NF-κB signaling pathways to maintain glucose homeostasis and regulate IR.

Betaine combined with traditional Chinese medicine ointment to treat skin wounds in microbially infected diabetic mice

BACKGROUND

Skin wounds are highly common in diabetic patients, and with increasing types of pathogenic bacteria and antibiotic resistance, wounds and infections in diabetic patients are difficult to treat and heal.

AIM

To explore the effects of betaine ointment (BO) in promoting the healing of skin wounds and reducing the inflammation and apoptosis of skin cells in microbially infected diabetic mice.

METHODS

By detecting the minimum inhibitory concentrations (MICs) of betaine and plant monomer components such as psoralen, we prepared BO with betaine as the main ingredient, blended it with traditional Chinese medicines such as gromwell root and psoralen, and evaluated its antibacterial effects and safety in vitro and in vivo. The skin infection wound models of ordinary mice and diabetic mice were constructed, and the OTC drugs mupirocin ointment and Zicao ointment were used as controls to evaluate the antibacterial effects in vivo and the anti-inflammatory and anti-apoptotic effects of BO.

RESULTS

The MICs of betaine against microorganisms such as Staphylococcus aureus (S. aureus), Candida albicans and Cryptococcus neoformans ranged from 4 to 32 μg/mL. Gromwell root and psoralea, both of which contain antimicrobial components, mixed to prepare BO with MICs ranging from 16 to 64 μg/mL, which is 32-256 times lower than those of Zicao ointment, although the MIC is greater than that of betaine. After 15 days of treatment with BO for USA300-infected ordinary mice, the wound scab removal rates were 83.3%, while those of mupirocin ointment and Zicao ointment were 66.7% and 0%, respectively, and the differences were statistically significant. In diabetic mice, the wound scab removal rate of BO and mupirolacin ointment was 80.0%, but BO reduced wound inflammation and the apoptosis of skin cells and facilitated wound healing.

CONCLUSION

The ointment prepared by mixing betaine and traditional Chinese medicine can effectively inhibit common skin microorganisms and has a strong effect on the skin wounds of sensitive or drug-resistant S. aureus-infected ordinary mice and diabetic mice.

The Coptidis Rhizoma and Bovis Calculus herb pair attenuates NASH and inhibits the NLRP3 inflammasome activation

The Coptidis Rhizoma and Bovis Calculus herb pair possesses clearing heat and detoxifying effects. The aim of this study was to reveal the effects and mechanisms of the herb pair in the treatment of NASH by network pharmacology and experimental verification. A network pharmacology-based approach was employed to predict the putative mechanism of the herb pair against NASH. The high-fat diet (HFD) and methionine/choline deficient (MCD) diet induced NASH models were used to evaluate efficacy and mechanism of the herb pair. Network pharmacological analysis showed that the herb pair modulated NOD-like receptor pathway. In the HFD mice, herb pair reduced body weight, blood sugar, serum ALT, AST, TBA, TC, TG and LDL-C contents, also improved the general morphology and pathological manifestations. Hepatic transcriptomics study showed that herb pair attenuated NASH by regulating NOD-like receptor signaling pathway. Western blotting showed that herb pair reduced the protein expression levels of NLRP3, cleaved Caspase-1 and cleaved IL-1β. In the MCD mice, herb pair also reduced serum ALT, ALT and TBA levels, improved liver pathological manifestations, inhibited the protein expression levels of NLRP3, cleaved Caspase-1 and cleaved IL-1β. Our findings proved that the Coptidis Rhizoma and Bovis Calculus herb pair attenuates NASH through suppression of NLRP3 inflammasome activation. This will demonstrate effective pharmacological evidence for the clinical application of herb pair.

Adipose-derived extracellular vesicles - a novel cross-talk mechanism in insulin resistance, non-alcoholic fatty liver disease, and polycystic ovary syndrome

Obesity is the best described risk factor for the development of non-alcoholic fatty liver disease (NAFLD)/metabolic dysfunction associated steatotic liver disease (MASLD) and polycystic ovary syndrome (PCOS) while the major pathogenic mechanism linking these entities is insulin resistance (IR). IR is primarily caused by increased secretion of proinflammatory cytokines, adipokines, and lipids from visceral adipose tissue. Increased fatty acid mobilization results in ectopic fat deposition in the liver which causes endoplasmic reticulum stress, mitochondrial dysfunction, and oxidative stress resulting in increased cytokine production and subsequent inflammation. Similarly, IR with hyperinsulinemia cause hyperandrogenism, the hallmark of PCOS, and inflammation in the ovaries. Proinflammatory cytokines from both liver and ovaries aggravate IR thus providing a complex interaction between adipose tissue, liver, and ovaries in inducing metabolic abnormalities in obese subjects. Although many pathogenic mechanisms of IR, NAFLD/MASLD, and PCOS are known, there is still no effective therapy for these entities suggesting the need for further evaluation of their pathogenesis. Extracellular vesicles (EVs) represent a novel cross-talk mechanism between organs and include membrane-bound vesicles containing proteins, lipids, and nucleic acids that may change the phenotype and function of target cells. Adipose tissue releases EVs that promote IR, the development of all stages of NAFLD/MASLD and PCOS, while mesenchymal stem cell-derived AVs may alleviate metabolic abnormalities and may represent a novel therapeutic device in NAFLD/MASLD, and PCOS. The purpose of this review is to summarize the current knowledge on the role of adipose tissue-derived EVs in the pathogenesis of IR, NAFLD/MASLD, and PCOS.

Role of autophagy in betaine-promoted hepatoprotection against non-alcoholic fatty liver disease in mice

Betaine, a compound found in plants and sea foods, is known to be beneficial against non-alcoholic fatty liver disease (NAFLD), but its hepatoprotective and anti-steatogenic mechanisms have been not fully understood. In the present study, we investigated the mechanisms underlying betaine-mediated alleviation of NAFLD induced by a choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) in mice, with special focus on the contribution of betaine-stimulated autophagy to NAFLD prevention. Male ICR mice were fed a CDAHFD with or without betaine (0.2-1% in drinking water) for 1 week. Betaine ameliorated the CDAHFD-induced fatty liver by restoring sulfur amino acid (SAA)-related metabolites, such as S-adenosylmethionine and homocysteine, and the phosphorylation of AMPK and ACC. In addition, it reduced the CDAHFD-induced ER stress (BiP, ATF6, and CHOP) and apoptosis (Bax, cleaved caspase-3, and cleaved PARP); however, it induced autophagy (LC3II/I and p62) which was downregulated by CDAHFD. To determine the role of autophagy in the improvement of NAFLD, chloroquine (CQ), an autophagy inhibitor, was injected into the mice fed a CDAHFD and betaine (0.5 % in drinking water). CQ did not affect SAA metabolism but reduced the beneficial effects of betaine as shown by the increases of hepatic lipids, ER stress, and apoptosis. Notably, the betaine-induced improvements in lipid metabolism determined by protein levels of p-AMPK, p-ACC, PPARα, and ACS1, were reversed by CQ. Thus, the results of this study suggest that the activation of autophagy is an important upstream mechanism for the inhibition of steatosis, ER stress, and apoptosis by betaine in NAFLD.

Dietary choline intake and non-alcoholic fatty liver disease (NAFLD) in U.S. adults: National Health and Nutrition Examination Survey (NHANES) 2017-2018

BACKGROUND

Whether there is an association between dietary choline intake and non-alcoholic fatty liver disease (NAFLD) in American adults remains unclear.

METHODS

Data came from the National Health and Nutrition Examination Survey 2017-2018. Choline intake was defined by the mean amounts of two 24 h dietary recalls, and choline intake was categorized into three groups according to the quartiles: inadequate (P75). Hepatic steatosis was assessed with FibroScan®, in which VCTE was employed with controlled attenuation to derive the controlled attenuation parameter (CAP), and NAFLD was defined as a CAP score ≥285 dB/m. Multivariable linear regression was performed to assess the linear relationship between choline intake and CAP. Multivariable logistics regression models were conducted to assess the association between choline intake status and NAFLD in the final sample and subgroup analysis was then performed in men and women.

RESULTS

The amount of dietary choline was inversely associated with CAP score (β = -0.262, 95% CI: -0.280, -0.245). Compared to inadequate choline intake, optimal choline intake was related to a lower risk of NAFLD (OR: 0.705, 95% CI: 0.704-0.706) in the final sample. Subgroup analysis by gender revealed that the highest choline intake status was associated with a lower risk of NAFLD both in females (OR: 0.764, 95% CI: 0.762-0.766), and males (OR: 0.955, 95% CI: 0.953-0.958) when compared to the lowest choline intake.

CONCLUSIONS

With the latest NHANES data, we found that higher dietary choline was associated with a lower risk of NAFLD in American adults, and such a relationship exists in both females and males.

The Interconnection between Hepatic Insulin Resistance and Metabolic Dysfunction-Associated Steatotic Liver Disease-The Transition from an Adipocentric to Liver-Centric Approach

The central mechanism involved in the pathogenesis of MAFLD is insulin resistance with hyperinsulinemia, which stimulates triglyceride synthesis and accumulation in the liver. On the other side, triglyceride and free fatty acid accumulation in hepatocytes promotes insulin resistance via oxidative stress, endoplasmic reticulum stress, lipotoxicity, and the increased secretion of hepatokines. Cytokines and adipokines cause insulin resistance, thus promoting lipolysis in adipose tissue and ectopic fat deposition in the muscles and liver. Free fatty acids along with cytokines and adipokines contribute to insulin resistance in the liver via the activation of numerous signaling pathways. The secretion of hepatokines, hormone-like proteins, primarily by hepatocytes is disturbed and impairs signaling pathways, causing metabolic dysregulation in the liver. ER stress and unfolded protein response play significant roles in insulin resistance aggravation through the activation of apoptosis, inflammatory response, and insulin signaling impairment mediated via IRE1/PERK/ATF6 signaling pathways and the upregulation of SREBP 1c. Circadian rhythm derangement and biological clock desynchronization are related to metabolic disorders, insulin resistance, and NAFLD, suggesting clock genes as a potential target for new therapeutic strategies. This review aims to summarize the mechanisms of hepatic insulin resistance involved in NAFLD development and progression.

Current insights into the interplay between gut microbiota-derived metabolites and metabolic-associated fatty liver disease

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a prevalent and challenging disease associated with a significant health and economic burden. MAFLD has been subjected to and widely investigated in many studies; however, the underlying pathogenesis and its progression have yet to understand fully. Furthermore, precise biomarkers for diagnosing and specific drugs for treatment are yet to be discovered. Increasing evidence has proven gut microbiota as the neglected endocrine organ that regulates homeostasis and immune response. Targeting gut microbiota is an essential strategy for metabolic diseases, including MAFLD. Gut microbiota in the gut-liver axis is connected through tight bidirectional links through the biliary tract, portal vein, and systemic circulation, producing gut microbiota metabolites. This review focuses on the specific correlation between gut microbiota metabolites and MAFLD. Gut microbiota metabolites are biologically active in the host and, through subsequent changes and biological activities, provide implications for MAFLD. Based on the review studies, gut-liver axis related-metabolites including short-chain fatty acids, bile acids (BAs), lipopolysaccharide, choline and its metabolites, indole and its derivates, branched-chain amino acids, and methionine cycle derivates was associated with MAFLD and could be promising MAFLD diagnosis biomarkers, as well as the targets for MAFLD new drug discovery.

Betaine as a Functional Ingredient: Metabolism, Health-Promoting Attributes, Food Sources, Applications and Analysis Methods

Betaine is a non-essential amino acid with proven functional properties and underutilized potential. The most common dietary sources of betaine are beets, spinach, and whole grains. Whole grains-such as quinoa, wheat and oat brans, brown rice, barley, etc.-are generally considered rich sources of betaine. This valuable compound has gained popularity as an ingredient in novel and functional foods due to the demonstrated health benefits that it may provide. This review study will provide an overview of the various natural sources of betaine, including different types of food products, and explore the potential of betaine as an innovative functional ingredient. It will thoroughly discuss its metabolic pathways and physiology, disease-preventing and health-promoting properties, and further highlight the extraction procedures and detection methods in different matrices. In addition, gaps in the existing scientific literature will be emphasized.

Gut-liver axis in the progression of nonalcoholic fatty liver disease: From the microbial derivatives-centered perspective

Nonalcoholic fatty liver disease (NAFLD) is one of the world's most common chronic liver diseases. However, its pathogenesis remains unclear. With the deepening of research, NAFLD is considered a metabolic syndrome associated with the environment, heredity, and metabolic disorders. Recently, the close relationship between the intestinal microbiome and NAFLD has been discovered, and the theory of the "gut-liver axis" has been proposed. In short, the gut bacteria directly reach the liver via the portal vein through the damaged intestinal wall or indirectly participate in the development of NAFLD through signaling pathways mediated by their components and metabolites. This review focuses on the roles of microbiota-derived lipopolysaccharide, DNA, peptidoglycan, bile acids, short-chain fatty acids, endogenous ethanol, choline and its metabolites, indole and its derivatives, and bilirubin and its metabolites in the progression of NAFLD, which may provide significative insights into the pathogenesis, diagnosis, and treatment for this highly prevalent liver disease.

Plant-derived bioactive compounds regulate the NLRP3 inflammasome to treat NAFLD

Non-alcoholic fatty liver disease (NAFLD) is a liver disorder characterized by abnormal accumulation of hepatic fat and inflammatory response with complex pathogenesis. Over activation of the pyrin domain-containing protein 3 (NLRP3) inflammasome triggers the secretion of interleukin (IL)-1β and IL-18, induces pyroptosis, and promotes the release of a large number of pro-inflammatory proteins. All of which contribute to the development of NAFLD. There is a great deal of evidence indicating that plant-derived active ingredients are effective and safe for NAFLD management. This review aims to summarize the research progress of 31 active plant-derived components (terpenoids, flavonoids, alkaloids, and phenols) that alleviate lipid deposition, inflammation, and pyroptosis by acting on the NLRP3 inflammasome studied in both in vitro and in vivo NAFLD models. These studies confirmed that the NLRP3 inflammasome and its related genes play a key role in NAFLD amelioration, providing a starting point for further study on the correlation of plant-derived compounds treatment with the NLRP3 inflammasome and NAFLD.

Preventive and therapeutic role of betaine in liver disease: A review on molecular mechanisms

Betaine is a kind of water-soluble quaternary amine-type alkaloid widely existing in food, such as wheat germ, beet, spinach, shrimp and wolfberry. As an important methyl donor and osmotic pressure regulator in human body, betaine plays an important role in a variety of physiological activities. In recent years, a large number of literatures have shown that betaine has good preventive and therapeutic effects on many liver diseases, including chemical or drug-induced liver injury, nonalcoholic fatty liver disease, alcoholic fatty liver disease, liver fibrosis, hepatitis B and hepatitis C. Therefore, by searching the databases of Web of Science, PubMed, SciFinder and CNKI, this paper has summarized the molecular mechanisms of betaine in improving liver diseases. The results show that the improvement of liver diseases by betaine is closely related to a variety of molecular mechanisms, including inhibition of inflammatory response, improvement of insulin resistance, reduction of endoplasmic reticulum stress, alleviation of liver oxidative stress, increase of autophagy, remodeling of intestinal flora and regulation of epigenetic modification. More importantly, nuclear transcription factor kappa (NF-κB), AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor α/γ (PPAR-α/γ), liver X receptor α (LXRα), protein kinase B (Akt), toll-like receptor 4 (TLR4) and cysteinyl aspartate specific proteinase-3 (Caspase-3) signaling pathways are considered as important molecular targets for betaine to improve liver diseases. These important findings will provide a direction and basis for further exploring the pathogenesis of various liver diseases and tapping the potential of betaine in the clinical treatment.

The interplay between metabolic dysregulations and non-alcoholic fatty liver disease in women after menopause

The hypoestrogenic period after menopause and associated metabolic imbalance might facilitate the onset of non-alcoholic fatty liver disease (NAFLD) and its progression. The prevalence of NAFLD increases in patients experiencing premature ovarian insufficiency, as well as surgical or natural menopause. The postmenopausal period is characterized by dyslipidemia and insulin resistance associated with an increased influx of free fatty acids to the liver with consequent steatosis and further progression of NAFLD. More than half of postmenopausal women with diabetes mellitus type 2 suffer from NAFLD. It is suggested that estrogens slow the progression of chronic liver diseases by suppression of inflammation, improvement of mitochondrial function, alleviation of oxidative stress, insulin resistance, and fibrogenesis. The hyperandrogenic state of polycystic ovary syndrome (PCOS) is associated with the development of NAFLD in women of reproductive age, but it is difficult to extend these findings to menopause due to inappropriate diagnosis of PCOS after menopause. Lifestyle intervention, including physical activity and dietary regimens, remains the first-line preventive and therapeutic option for NAFLD. There are contradictory reports on the use of menopausal hormonal therapy (MHT) and NAFLD. It is necessary to investigate the potential effects of estradiol dose, progesterone type, selective estrogen receptor modulators and tissue-selective estrogen complex compounds on NAFLD development and progression in postmenopausal women. The present review aims to explore the pathophysiological and clinical aspects of liver metabolic disturbances in women after menopause, focusing on the possible preventive and therapeutic strategies in NAFLD, including the potential role of MHT.

Beneficial Effects of Betaine: A Comprehensive Review

Medicinal herbs and many food ingredients possess favorable biological properties that contribute to their therapeutic activities. One such natural product is betaine, a stable, nontoxic natural substance that is present in animals, plants, and microorganisms. Betaine is also endogenously synthesized through the metabolism of choline or exogenously consumed through dietary intake. Betaine mainly functions as (i) an osmolyte and (ii) a methyl-group donor. This review describes the major physiological effects of betaine in whole-body health and its ability to protect against both liver- as well as non-liver-related diseases and conditions. Betaine's role in preventing/attenuating both alcohol-induced and metabolic-associated liver diseases has been well studied and is extensively reviewed here. Several studies show that betaine protects against the development of alcohol-induced hepatic steatosis, apoptosis, and accumulation of damaged proteins. Additionally, it can significantly prevent/attenuate progressive liver injury by preserving gut integrity and adipose function. The protective effects are primarily associated with the regulation of methionine metabolism through removing homocysteine and maintaining cellular SAM:SAH ratios. Similarly, betaine prevents metabolic-associated fatty liver disease and its progression. In addition, betaine has a neuroprotective role, preserves myocardial function, and prevents pancreatic steatosis. Betaine also attenuates oxidant stress, endoplasmic reticulum stress, inflammation, and cancer development. To conclude, betaine exerts significant therapeutic and biological effects that are potentially beneficial for alleviating a diverse number of human diseases and conditions.