Role of the PNPLA3 polymorphism rs738409 on silymarin + vitamin E response in subjects with non-alcoholic fatty liver disease

Oxidative Stress as a Target for Non-Pharmacological Intervention in MAFLD: Could There Be a Role for EVOO?

Oxidative stress plays a central role in most chronic liver diseases and, in particular, in metabolic dysfunction-associated fatty liver disease (MAFLD), the new definition of an old condition known as non-alcoholic fatty liver disease (NAFLD). The mechanisms leading to hepatocellular fat accumulation in genetically predisposed individuals who adopt a sedentary lifestyle and consume an obesogenic diet progress through mitochondrial and endoplasmic reticulum dysfunction, which amplifies reactive oxygen species (ROS) production, lipid peroxidation, malondialdehyde (MDA) formation, and influence the release of chronic inflammation and liver damage biomarkers, such as pro-inflammatory cytokines. This close pathogenetic link has been a key stimulus in the search for therapeutic approaches targeting oxidative stress to treat steatosis, and a number of clinical trials have been conducted to date on subjects with NAFLD using drugs as well as supplements or nutraceutical products. Vitamin E, Vitamin D, and Silybin are the most studied substances, but several non-pharmacological approaches have also been explored, especially lifestyle and diet modifications. Among the dietary approaches, the Mediterranean Diet (MD) seems to be the most reliable for affecting liver steatosis, probably with the added value of the presence of extra virgin olive oil (EVOO), a healthy food with a high content of monounsaturated fatty acids, especially oleic acid, and variable concentrations of phenols (oleocanthal) and phenolic alcohols, such as hydroxytyrosol (HT) and tyrosol (Tyr). In this review, we focus on non-pharmacological interventions in MAFLD treatment that target oxidative stress and, in particular, on the role of EVOO as one of the main antioxidant components of the MD.

Are we ready for genetic testing in metabolic dysfunction-associated steatotic liver disease?

Metabolic dysfunction-associated steatotic liver disease (MASLD), with its steadily increasing prevalence, represents now a major problem in public health. A proper referral could benefit from tools allowing more precise risk stratification. To this end, in recent decades, several genetic variants that may help predict and refine the risk of development and progression of MASLD have been investigated. In this review, we aim to discuss the role genetics in MASLD plays in everyday clinical practice. We performed a comprehensive literature search of PubMed for relevant publications. Available evidence highlights the emergence of genetic-based noninvasive algorithms for diagnosing fatty liver, metabolic dysfunction-associated steatohepatitis, fibrosis progression and occurrence of liver-related outcomes including hepatocellular carcinoma. Nevertheless, their accuracy is not optimal and application in everyday clinical practice remains challenging. Furthermore, susceptible genetic markers have recently become subjects of great scientific interest as therapeutic targets in precision medicine. In conclusion, decisional algorithms based on genetic testing in MASLD to facilitate the clinician decisions on management and treatment are under growing investigation and could benefit from artificial intelligence methodology.

What do we know about nutrient-based strategies targeting molecular mechanisms associated with obesity-related fatty liver disease?

Obesity is a risk factor for developing nonalcoholic fatty liver disease (NAFLD), and the associated molecular mechanisms could be targeted with nutrient-based strategies. Therefore, it is necessary to review the current mechanisms to propose further treatments. Obesity facilitates the onset of insulin resistance, lipidic abnormalities, hepatic fat accumulation, lipid peroxidation, mitochondrial dysfunction, excessive reactive oxygen species (ROS) production, and inflammation, all related to further steatosis progression and fibrosis. Microbiota alterations can also influence liver disease by the translocation of pathogenic bacteria, energy extraction from short chain fatty acids (SCFAs), intestinal suppression of the expression of fasting-induced adipose factor (FIAF), reduction of bile acids, and altered choline metabolism. There are also genetic polymorphisms in metabolic proteins that predispose to a higher risk of liver diseases, such as those found in the patatin-like phospholipase domain-containing 3 (PNPLA3), transmembrane 6 superfamily member 2 (TM6SF2), membrane-bound O-acyltransferase domain-containing 7 (MBOAT7) or also known as lysophosphatidylinositol acyltransferase 1 (LPIAT1), transmembrane channel-like 4 genes (TMC4), fat mass and obesity-associated protein (FTO), the b Klotho (KLB) and carboxylesterase (CES1). No clear dietary guidelines target all mechanisms related to NAFLD development and progression. However, energy and carbohydrate intake restriction, regular physical exercise, supplementation of antioxidants, and restoration of gut microbiota seem to have beneficial effects on the new proposed features of NAFLD.

Multi-Omics Nutritional Approaches Targeting Metabolic-Associated Fatty Liver Disease

Currently, metabolic-associated fatty liver disease (MAFLD) is a leading global cause of chronic liver disease, and is expected to become one of the most common indications of liver transplantation. MAFLD is associated with obesity, involving multiple mechanisms such as alterations in lipid metabolism, insulin resistance, hyperinflammation, mitochondrial dysfunction, cell apoptosis, oxidative stress, and extracellular matrix formation. However, the onset and progression of MAFLD is variable among individuals, being influenced by intrinsic (personal) and external environmental factors. In this context, sequence structural variants across the human genome, epigenetic phenomena (i.e., DNA methylation, histone modifications, and long non-coding RNAs) affecting gene expression, gut microbiota dysbiosis, and metabolomics/lipidomic fingerprints may account for differences in MAFLD outcomes through interactions with nutritional features. This knowledge may contribute to gaining a deeper understanding of the molecular and physiological processes underlying MAFLD pathogenesis and phenotype heterogeneity, as well as facilitating the identification of biomarkers of disease progression and therapeutic targets for the implementation of tailored nutritional strategies. This comprehensive literature review highlights the potential of nutrigenetic, nutriepigenetic, nutrimetagenomic, nutritranscriptomics, and nutrimetabolomic approaches for the prevention and management of MAFLD in humans through the lens of precision nutrition.

Impact of Genetic Polymorphism on Response to Therapy in Non-Alcoholic Fatty Liver Disease

In the last decades, the global prevalence of non-alcoholic fatty liver disease (NAFLD) has reached pandemic proportions with derived major health and socioeconomic consequences; this tendency is expected to be further aggravated in the coming years. Obesity, insulin resistance/type 2 diabetes mellitus, sedentary lifestyle, increased caloric intake and genetic predisposition constitute the main risk factors associated with the development and progression of the disease. Importantly, the interaction between the inherited genetic background and some unhealthy dietary patterns has been postulated to have an essential role in the pathogenesis of NAFLD. Weight loss through lifestyle modifications is considered the cornerstone of the treatment for NAFLD and the inter-individual variability in the response to some dietary approaches may be conditioned by the presence of different single nucleotide polymorphisms. In this review, we summarize the current evidence on the influence of the association between genetic susceptibility and dietary habits in NAFLD pathophysiology, as well as the role of gene polymorphism in the response to lifestyle interventions and the potential interaction between nutritional genomics and other emerging therapies for NAFLD, such as bariatric surgery and several pharmacologic agents.

Lifestyle and silymarin: a fight against liver damage in NAFLD associated - prediabetic disease

Background

Nonalcoholic fatty liver disease (NAFLD) is common in both prediabetic patients and healthy overweight individuals, yet it remains understudied. This study investigates the effects of hepatic steatosis on fibrosis and evaluates the major predictors of liver injury in prediabetes and whether this damage is reversible with Mediterranean diet and administration of the nutraceutical silymarin.

Methods

First, a case-control study was conducted in which 212 patients with prediabetes, not known to have NAFLD, and 126 healthy controls underwent clinical evaluation, transient elastography with measurement of liver stiffness (LS) and controlled attenuation parameter (CAP). Subsequently, the 212 prediabetic patients were enrolled into a prospective randomized interventional study: 104 were allocated to Mediterranean diet alone while 108 followed Mediterranean diet plus supplementation with silymarin (a flavonolignan complex isolated from Silybum marianum and Morus alba). The administered silymarin dose was 210 mg twice daily for 6 months. Clinical and instrumental evaluations were repeated at the end of the 6 month-study period. Prediabetics were genotyped for patatin like phospholipase domain containing 3 (PNPLA3).

Results

In the case-control study, 29% of prediabetic patients have significant fibrosis defined as LS ≥ 7.9 kPa vs only 3% of controls (p < 0.001). PNPLA3 genotype CG/GG are significantly associated with significant fibrosis LS ≥ 7.9 relative to CC genotype χ2(1) = 76.466, p < 0.001. Binomial regression analysis shows that increase in BMI, ALT and AST are significantly associated with increased likelihood of significant fibrosis (χ2(7) = 191.9, p < .001) prior to intervention. In the randomized interventional study, prediabetics following Mediterranean diet alone (group 1) experienced a significant regression of fibrosis and decrease in ALT, HbA1c, FBS after 6 months (p < 0.001); similar findings were observed in patients following Mediterranean diet plus silymarin regimen (group 2); group 2 had a significant decrease in HbA1c relative to group 1 (95% CI: 37.8–38.6 vs 39.5–40.3, p < 0.001).

Conclusion

PNPLA3 genotype CG/GG and elevated BMI are the major predictors of significant fibrosis in prediabetic patients prior to intervention in this study. Mediterranean diet either alone or with silymarin treatment for 6 months leads to significant regression of liver damage and improvement of the glycemic profile in prediabetic patients. Yet, as combination treatment of silymarin with Mediterranean diet shows significant reduction of HbA1c when compared to diet alone, this suggests that silymarin may exert an independent anti-glycemic action.

Higher flavonoid intake is associated with a lower progression risk of non-alcoholic fatty liver disease in adults: a prospective study

Flavonoid-rich foods have shown a beneficial effect against non-alcoholic fatty liver disease (NAFLD) in short-term randomised trials. It is uncertain whether the usual dietary intake of flavonoids may benefit patients with NAFLD. The present study evaluated the association between the usual intake of flavonoids and the risk of progression in NAFLD. The prospective study included 2694 adults from the Guangzhou Nutrition and Health Study. Face-to-face interviews using a seventy-nine-item FFQ were administered to assess habitual dietary flavonoid intake, while abdominal ultrasonography was conducted to evaluate the presence and degree of NAFLD, with measurements conducted 3 years apart. After adjustment for potential confounders, higher flavonoid intakes were gradely associated with reduced risks of worsen NAFLD status. The relative risks of worsening (v. non-worsening) NAFLD in the highest (v. lowest) quintile were 0·71 (95 % CI 0·54, 0·93) for total flavonoids, 0·74 (95 % CI 0·57, 0·95) for flavanones, 0·74 (95 % CI 0·56, 0·96) for flavan-3-ols, 0·90 (95 % CI 0·68, 1·18) for flavonols, 0·73 (95 % CI 0·56, 0·93) for flavones, 0·79 (95 % CI 0·61, 1·02) for isoflavones and 0·74 (95 % CI 0·57, 0·96) for anthocyanins. An L-shaped relationship was observed between total flavonoid intake and the risk of NAFLD progression. Path analyses showed that the association between flavonoids and NAFLD progression was mediated by decreases in serum cholesterol and homeostasis model assessment of insulin resistance. This prospective study showed that higher flavonoid intake was associated with a lower risk of NAFLD progression in the elderly overweight/obese Chinese population.

Antidiabetic Therapy in the Treatment of Nonalcoholic Steatohepatitis

Liver-related diseases are the third-leading causes (9.3%) of mortality in type 2 diabetes (T2D) in Japan. T2D is closely associated with nonalcoholic fatty liver disease (NAFLD), which is the most prevalent chronic liver disease worldwide. Nonalcoholic steatohepatitis (NASH), a severe form of NAFLD, can lead to hepatocellular carcinoma (HCC) and hepatic failure. No pharmacotherapies are established for NASH patients with T2D. Though vitamin E is established as a first-line agent for NASH without T2D, its efficacy for NASH with T2D recently failed to be proven. The effects of pioglitazone on NASH histology with T2D have extensively been established, but several concerns exist, such as body weight gain, fluid retention, cancer incidence, and bone fracture. Glucagon-like peptide 1 (GLP-1) receptor agonists and sodium-glucose cotransporter 2 (SGLT2) inhibitors are expected to ameliorate NASH and NAFLD (LEAN study, LEAD trial, and E-LIFT study). Among a variety of SGLT2 inhibitors, dapagliflozin has already entered the phase 3 trial (DEAN study). A key clinical need is to determine the kinds of antidiabetic drugs that are the most appropriate for the treatment of NASH to prevent the progression of hepatic fibrosis, resulting in HCC or liver-related mortality without increasing the risk of cardiovascular or renal events. Combination therapies, such as glucagon receptor agonist/GLP-1 or gastrointestinal peptide/GLP-1, are under development. This review focused on antidiabetic agents and future perspectives on the view of the treatment of NAFLD with T2D.

THE EFFECTS OF REALSIL (SILYBIN-PHOSPHOLIPID-VITAMIN E COMPLEX) ON LIVER ENZYMES IN PATIENTS WITH NON-ALCOHOLIC FATTY LIVER DISEASE (NAFLD) OR NON-ALCOHOLIC STEATO-HEPATITIS (NASH): A SYSTEMATIC REVIEW AND META-ANALYSIS OF RCTS

Background

The aim of the present study was to systematically review the effects of Realsil (silybin-phospholipid-vitamin E complex) on liver enzymes in patients with NAFLD or NASH.

Methods

We searched Web of Science, MEDLINE, Google Scholar, Cochrane Library, Science Direct, ProQuest, Scopus, and 1868 articles were found up to December 2018. Four studies that examined the effect of Realsil intake on liver enzymes among NAFLD or NASH patients were included. Exclusion criteria include: animal studies, studies with the design other than clinical trials, studies on non-adult individuals, studies that assess the effect of vitamin E, silybin, or phospholipid solely, studies that examined the effect of Realsil on other outcomes, or studies with insufficient data.

Results

The analysis demonstrated that Realsil intake led to a significant decrease in Gamma-Glutamyl Transpeptidase (GGT) levels (standardized mean difference (SMD) =-0.37; 95% confidence interval (CI]): -0.68 to -0.06). Realsil intake non-significantly decrease alanine transaminase (ALT) levels (SMD=-1.02 U/L; 95% CI: -2.23 to 0.20) and non-significantly increase aspartate aminotransferase (AST) levels (SMD = 0.17 U/L; 95% CI: -0.26-0.61).

Conclusion

Realsil intake was associated with a significantly decreased circulating GGT level without any significant effect on AST and ALT levels.

Association between Smoking and Liver Fibrosis among Patients with Nonalcoholic Fatty Liver Disease

OBJECTIVE

We aimed at analyzing the role of smoking in hepatic fibrosis in patients with nonalcoholic fatty liver disease (NAFLD) and at exploring the related risk factors.

METHODS

This was a cross-sectional study that included a total of 225 patients with NAFLD. Among them, 127 were nonsmokers and 98 were smokers. Liver significant fibrosis was diagnosed when the liver stiffness (LS) value was higher than 7.4 kPa. The diagnostic criterion for NAFLD was a controlled attenuation parameter (CAP) value of >238 dB/m. The CAP and LS values were measured using FibroScan.

RESULTS

FibroScan showed that the LS value in the smokers was significantly higher than that in the nonsmokers (10.12 ± 10.38 kPa vs. 7.26 ± 6.42 kPa, P=0.013). The proportions of patients with liver significant fibrosis and advanced liver fibrosis among the smokers were significantly higher than those among the nonsmokers (P=0.046). Univariate analysis showed that age, weight, high AST level, low PLT level, and smoking were the risk factors associated with liver fibrosis in the smokers with NAFLD while multivariate analysis showed that age (OR = 1.029, P=0.021), high AST level (OR = 1.0121, P=0.025), and smoking (OR = 1.294, P=0.015) were the independent risk factors associated with liver fibrosis in the patients with NAFLD. Moreover, high AST level (OR = 1.040, P=0.029), smoking index (OR = 1.220, P=0.019), and diabetes mellitus (OR = 1.054, P=0.032) were the independent risk factors for liver fibrosis among the smokers with NAFLD.

CONCLUSION

This study showed that smoking was closely associated with liver fibrosis among the patients with NAFLD. For patients with NAFLD who smoke, priority screening and timely intervention should be provided if they are at risk of liver fibrosis.