Agents for the treatment of fatty liver disease: focus on essential phospholipids

Non-Alcoholic Fatty Liver Disease, Awareness of a Diagnostic Challenge—A Clinician’s Perspective

Non-alcoholic fatty liver disease (NAFLD) is the main cause of chronic liver disease globally. NAFLD is a complex pathology, considered to be the hepatic expression of metabolic syndrome (MetS). It is supposed to become the main indication for liver transplantation in the coming years and is estimated to affect 57.5–74.0% of obese people, 22.5% of children and 52.8% of obese children, with 50% of individuals with type 2 diabetes being diagnosed with NAFLD. Recent research has proved that an increase in adipose tissue insulin resistance index is an important marker of liver injury in patients with NAFLD. Despite being the main underlying cause of incidental liver damage and a growing worldwide health problem, NAFLD is mostly under-appreciated. Currently, NAFLD is considered a multifactorial disease, with various factors contributing to its pathogenesis, associated with insulin resistance and diabetes mellitus, but also with cardiovascular, kidney and endocrine disorders (polycystic ovary syndrome, hypothyroidism, growth hormone deficiency). Hepatitis B and hepatitis C, sleep apnea, inflammatory bowel diseases, cystic fibrosis, viral infections, autoimmune liver diseases and malnutrition are some other conditions in which NAFLD can be found. The aim of this review is to emphasize that, from the clinician’s perspective, NAFLD is an actual and valuable key diagnosis factor for multiple conditions; thus, efforts need to be made in order to increase recognition of the disease and its consequences. Although there is no global consensus, physicians should consider screening people who are at risk of NAFLD. A large dissemination of current concepts on NAFLD and an extensive collaboration between physicians, such as gastroenterologists, internists, cardiologists, diabetologists, nutritionists and endocrinologists, is equally needed to ensure we have the knowledge and resources to address this public health challenge.

The Role of Dietary Ingredients and Herbs in the Prevention of Non-Communicable Chronic Liver Disease

BACKGROUND

Liver diseases are among the most commonly diagnosed conditions, with the main risk factors being inappropriate lifestyles, including poor diet, excessive alcohol consumption, low physical activity and smoking, including electronic cigarettes. Non-communicable chronic liver diseases also often develop as a result of accompanying overweight and obesity, as well as type 2 diabetes.

METHODS

The literature on risk factors for non-communicable chronic liver diseases, which show a high strong influence on their occurrence, was analysed.

RESULTS

Measures to prevent non-communicable chronic liver disease include the selection of suitable food ingredients that have proven protective effects on the liver. Such ingredients include dietary fibre, probiotics, herbs, various types of polyphenols and fatty acids (omega-3).

CONCLUSIONS

Because of their liver-protective effects, nutritionists recommend consuming vegetables, fruits, herbs and spices that provide valuable ingredients with anti-inflammatory and anti-cancer effects. These components should be provided with food and, in the case of probiotics, supplementation appears to be important. As a preventive measure, a diet rich in these nutrients is therefore recommended, as well as one that prevents overweight and other diseases that can result in liver disease.

Mapping global research trends: Nutrition associations with nonalcoholic fatty liver disease - a Scopus bibliometric analysis

BACKGROUND

Several bibliometric analyses have been carried out to identify research hotspots and trends in nonalcoholic fatty liver disease (NAFLD) research. Nonetheless, there are still significant knowledge gaps that must be filled to advance our understanding of and ability to treat NAFLD.

AIM

To evaluate, through bibliometric and visual analysis, the current status of related research, related research frontiers, and the developmental trends in the field of diet and NAFLD.

METHODS

We retrieved publications about diet and NAFLD published between 1987 and 2022 from Scopus. Next, we used VOSviewer 1.6.20 to perform bibliometric analysis and visualization.

RESULTS

We found a total of 1905 studies, including 1637 (85.93%) original articles and 195 (10.24%) reviews, focused on the examination of NAFLD and its correlation with diet that were published between 1987 and 2022. Among the remaining five types of documents, 38 were letters, notes, editorials, meeting minutes, or brief surveys, representing 1.99% of the total documents. The countries with the most publications on this topic were China (n = 539; 28.29%), followed by the United States (n = 379; 19.90%), Japan (n = 133; 6.98%), and South Korea (n = 127; 6.6%). According to the citation analysis, the retrieved papers were cited an average of 32.3 times and had an h-index of 106, with 61014 total citations. The two main clusters on the map included those related to: (1) Inflammation and oxidative stress; and (2) Dietary interventions for NAFLD.

CONCLUSION

This was the first study to use data taken from Scopus to visualize network mapping in a novel bibliometric analysis of studies focused on diet and NAFLD. After 2017, the two domains that received the most attention were "dietary interventions for NAFL"' and "'inflammation and oxidative stress implicated in NAFLD and its correlation with diet." We believe that this study provides important information for academics, dietitians, and doctors, and that additional research on dietary interventions and NAFLD is warranted.

Effect of essential phospholipids on hepatic steatosis in metabolic dysfunction-associated steatotic liver disease associated with type 2 diabetes mellitus and/or hyperlipidemia and/or obesity: study protocol of a randomized, double-blind, phase IV clinical trial

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a predominant chronic liver condition globally and is strongly associated with obesity, diabetes mellitus, and dyslipidemia. Essential phospholipids (EPL) are recommended as supportive treatment for managing liver conditions, including MASLD or metabolic dysfunction-associated steatohepatitis, cirrhosis, and viral hepatitis. While efficacy of EPL as an adjunctive therapy in MASLD treatment has been established earlier, certain aspects of its usage such as the impact of standard-of-care parameters, effect of EPL on quality of life (QoL) and change in symptoms evaluation in patients with MASLD remain unexplored. The proposed trial aims to assess the efficacy and safety of EPL and the subsequent QoL of patients with MASLD associated with type 2 diabetes mellitus (T2DM) and/or hyperlipidemia and/or obesity.

METHODS

This is a multicenter, multinational, double-blind, randomized, two-arm, placebo-controlled, parallel-group, phase IV clinical trial. The trial is being conducted in approximately 190 patients who are randomized on a 1:1 basis either to the EPL arm (Essentiale® 1800 mg/day orally + standard of care) or placebo arm (placebo + standard of care). The primary outcome is to assess the efficacy of EPL on hepatic steatosis, as measured by transient elastography, from baseline to 6 months. The secondary outcomes include change in QoL parameters, as measured by the Chronic Liver Disease Questionnaire-metabolic dysfunction-associated steatotic liver disease/ metabolic dysfunction-associated steatohepatitis and change in symptom evaluation (using the Global Overall Symptom scale) from baseline to 6 months for symptoms, including asthenia, feeling depressed, abdominal pain/discomfort, or fatigue.

DISCUSSION

The current protocol design will allow to comprehensively explore the efficacy of EPL added to the standard of care on hepatic steatosis and QoL and its safety in patients with MASLD associated with T2DM and/or hyperlipidemia and/or obesity by assessing various outcome measures.

TRIAL REGISTRATION

European Union Clinical Trials Register, EudraCT, 2021-006069-39. Registered on March 13, 2022.

Soybean polyenylphosphatidylcholine (PPC) is beneficial in liver and extrahepatic tissue injury: An update in experimental research

Polyenylphosphatidylcholine (PPC) is a purified polyunsaturated phosphatidylcholine extract of soybeans. This article updates PPC's beneficial effects on various forms of liver cell injury and other tissues in experimental research. PPC downregulates hepatocyte CYP2E1 expression and associated hepatotoxicity, as well as attenuates oxidative stress, apoptosis, lipoprotein oxidation and steatosis in alcoholic and nonalcoholic liver injury. PPC inhibits pro-inflammatory cytokine production, while stimulating anti-inflammatory cytokine secretion in ethanol or lipopolysaccharide-stimulated Kupffer cells/macrophages. It promotes M2-type macrophage polarization and metabolic reprogramming of glucose and lipid metabolism. PPC mitigates steatosis in NAFLD through inhibiting polarization of pro-inflammatory M1-type Kupffer cells, alleviating metabolic inflammation, remodeling hepatic lipid metabolism, correcting imbalances between lipogenesis and lipolysis and enhancing lipoprotein secretion from hepatocytes. PPC is antifibrotic by preventing progression of alcoholic hepatic fibrosis in baboons and also prevents CCl4-induced fibrosis in rats. PPC supplementation replenishes the phosphatidylcholine content of damaged cell membranes, resulting in increased membrane fluidity and functioning. Phosphatidylcholine repletion prevents increased membrane curvature of the endoplasmic reticulum and Golgi and decreases sterol regulatory element binding protein-1-mediated lipogenesis, reducing steatosis. PPC remodels gut microbiota and affects hepatic lipid metabolism via the gut-hepatic-axis and also alleviates brain inflammatory responses and cognitive impairment via the gut-brain-axis. Additionally, PPC protects extrahepatic tissues from injury caused by various toxic compounds by reducing oxidative stress, inflammation, and membrane damage. It also stimulates liver regeneration, enhances sensitivity of cancer cells to radiotherapy/chemotherapy, and inhibits experimental hepatocarcinogenesis. PPC's beneficial effects justify it as a supportive treatment of liver disease.

Essential phospholipids impact cytokine secretion and alter lipid-metabolizing enzymes in human hepatocyte cell lines

BACKGROUND

Essential phospholipids (EPL) are hepatoprotective.

METHODS

The effects on interleukin (IL)-6 and -8 secretion and on certain lipid-metabolizing enzymes of non-cytotoxic concentrations of EPL (0.1 and 0.25 mg/ml), polyenylphosphatidylcholine (PPC), and phosphatidylinositol (PtdIns) (both at 0.1 and 1 mg/ml), compared with untreated controls, were assessed in human hepatocyte cell lines (HepG2, HepaRG, and steatotic HepaRG).

RESULTS

Lipopolysaccharide (LPS)-induced IL-6 secretion was significantly decreased in HepaRG cells by most phospholipids, and significantly increased in steatotic HepaRG cells with at least one concentration of EPL and PtdIns. LPS-induced IL-8 secretion was significantly increased in HepaRG and steatotic HepaRG cells with all phospholipids. All phospholipids significantly decreased amounts of fatty acid synthase in steatotic HepaRG cells and the amounts of acyl-CoA oxidase in HepaRG cells. Amounts of lecithin cholesterol acyltransferase were significantly decreased in HepG2 and HepaRG cells by most phospholipids, and significantly increased with 0.1 mg/ml PPC (HepaRG cells) and 1 mg/ml PtdIns (steatotic HepaRG cells). Glucose-6-phosphate dehydrogenase activity was unaffected by any phospholipid in any cell line.

CONCLUSIONS

EPL, PPC, and PtdIns impacted the secretion of pro-inflammatory cytokines and affected amounts of several key lipid-metabolizing enzymes in human hepatocyte cell lines. Such changes may help liver function improvement, and provide further insights into the EPL's mechanism of action.

Essential phospholipids decrease apoptosis and increase membrane transport in human hepatocyte cell lines

Background

Essential phospholipids (EPL) have hepatoprotective effects across many liver diseases/conditions. The impact of EPL on hepatocyte function in vitro was investigated.

Methods

Effects of noncytotoxic concentrations of EPL (0.1 and 0.25 mg/ml), and its constituents, polyenylphosphatidylcholine (PPC) and phosphatidylinositol (PI) (both at 0.1 and 1 mg/ml), on membrane fluidity, apoptosis and extracellular transport versus controls were investigated in human hepatocyte cell lines (HepG2, HepaRG, steatotic HepaRG). 

Results

Significantly increased membrane fluidity occurred with all 3 phospholipids (PLs) in HepG2 cultures, and with PI (1 mg/ml) in steatotic HepaRG cells. Significantly decreased tamoxifen-induced apoptosis was observed in HepG2 cells with EPL, PPC and PI. Breast cancer resistance protein (BCRP) activity was significantly increased by EPL and PI in HepG2 cells. Multidrug resistance-associated protein 2 (MRP-2) activity was unaffected by any PL in HepG2 cells, and significantly increased by EPL, PI and PPC (1 mg/ml) in HepaRG cells, and by PI (1 mg/ml) in steatotic HepaRG cells. Bile salt export protein (BSEP) activity in HepG2 cells and steatotic HepaRG cells was significantly increased by EPL (0.25 mg/ml), and PPC (both concentrations), but not by PI. The PLs had no effects on HepaRG cell BSEP activity. P-glycoprotein (P-GP) activity was significantly increased by all compounds in HepG2 cells. PI (1 mg/ml) significantly increased P-GP activity in HepaRG and steatotic HepaRG cells.

Conclusions

EPL, PPC, and PI increased hepatocyte membrane fluidity, decreased apoptosis and increased hepatocellular export, all of which may improve liver function. These in-vitro investigations provide valuable insights into the mechanism of action of EPL.

Healthcare practitioners' diagnostic and treatment practice patterns of nonalcoholic fatty liver disease in Poland: a cross-sectional survey

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) awareness is low. NAFLD diagnosis and management by gastroenterologists (GEs) and general practitioners (GPs) in Poland were evaluated.

METHODS

RESTORE was an observational, noninterventional, retrospective cross-sectional survey performed among GEs and GPs with at least 3 years' experience. Computer-assisted web interviews were completed. GEs provided information from patient records.

RESULTS

Mean experience was 14.2 (95 GEs) and 22.6 (115 GPs) years. Mean patient numbers with liver disorders consulted per month were 36 (13%; GEs) and 51 (6%; GPs); ~50% were patients with NAFLD. All GEs/GPs used ultrasound; most evaluated transaminases and gamma-glutamyl transferase. More GEs used other imaging techniques and a larger spectrum of laboratory tests than GPs. Physician-identified NAFLD key symptoms were similar for GEs/GPs. GEs noticed less obvious symptoms (abdominal discomfort, drowsiness, fatigability, lack of energy) vs. GPs (abdominal pain/discomfort, dyspepsia). Common comorbidities in NAFLD were similar in GE/GP responses. NAFLD interventions by GEs/GPs (% patients) were diet/lifestyle/pharmacological interventions (54%/59%), diet/lifestyle changes alone (41%/31%) or pharmacological interventions alone (5%/10%). The top three criteria for supportive pharmacological selection were efficacy, tolerability and quality of life improvement for GEs/GPs. The five supportive treatments most commonly prescribed by GEs/GPs were essential phospholipids, ursodeoxycholic acid, timonacic, silybinin/silymarin and ornithine + choline. Information from patient records (n = 380) confirmed GEs responses.

CONCLUSIONS

NAFLD is not a silent disease as physicians and patients reported many, albeit nonspecific, symptoms. This cross-sectional survey provides important insights into clinical management of NAFLD by GEs and GPs in Poland.