Management of Obesity and Nonalcoholic Fatty Liver Disease: A Literature Review

Effects of oleoylethanolamide supplementation on the expression of lipid metabolism-related genes and serum NRG4 levels in patients with non-alcoholic fatty liver disease: A randomized controlled trial

BACKGROUND

This study investigated the effects of oleoylethanolamide (OEA) supplementation on the expression levels of SIRT1, AMPK, PGC-1α, PPAR-γ, CEBP-α and CEBP-β genes and serum neuregulin 4 (NRG4) levels in patients with non-alcoholic fatty liver diseases (NAFLD).

METHODS

Sixty obese patients with NAFLD were equally allocated into either OEA or placebo group for 12 weeks. The mRNA expression levels of genes were determined using the reverse transcription polymerase chain reaction (RT-PCR) technique. Serum NRG4 level was also assessed using an enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS

At the endpoint, mRNA expression levels of SIRT1(p = 0.001), PGC-1α (p = 0.011) and AMPK (p = 0.019) were significantly higher in the OEA group compared to placebo group. However, no significant differences were observed in the expression levels of PPAR-γ, CEBP-α and CEBP-β between the two groups. Serum NRG4 levels significantly increased in the OEA group compared with the placebo group after controlling for confounders (p = 0.027). In the OEA group, significant relationships were found between percent of changes in the expression levels of the SIRT1, AMPK and PGC-1α as well as serum NRG4 level with percent of changes in some anthropometric measures. Moreover, in the intervention group, percent of changes in high-density lipoprotein cholesterol was positively correlated with percent of changes in the expression levels of the SIRT1 and AMPK. While, percent of changes in triglyceride was inversely correlated with percent of changes in the expression levels of SIRT1.

CONCLUSION

OEA could beneficially affect expression levels of some lipid metabolism-related genes and serum NRG4 level. "REGISTERED UNDER IRANIAN REGISTRY OF CLINICAL TRIALS IDENTIFIER NO: IRCT20090609002017N32".

Clinical Classification of Obesity and Implications for Metabolic Dysfunction-Associated Fatty Liver Disease and Treatment

Obesity,and metabolic dysfunction-associated fatty liver disease (MAFLD) have reached epidemic proportions globally. Obesity and MAFLD frequently coexist and act synergistically to increase the risk of adverse clinical outcomes (both hepatic and extrahepatic). Type 2 diabetes mellitus (T2DM) is the most important risk factor for rapid progression of steatohepatitis and advanced fibrosis. Conversely, the later stages of MAFLD are associated with an increased risk of T2DM incident. According to the proposed criteria, MAFLD is diagnosed in patients with liver steatosis and in at least one in three: overweight or obese, T2DM, or signs of metabolic dysregulation if they are of normal weight. However, the clinical classification and correlation between obesity and MAFLD is more complex than expected. In addition, treatment for obesity and MAFLD are associated with a reduced risk of T2DM, suggesting that liver-based treatments could reduce the risk of developing T2DM. This review describes the clinical classification of obesity and MAFLD, discusses the clinical features of various types of obesity and MAFLD, emphasizes the role of visceral obesity and insulin resistance (IR) in the development of MAFLD,and summarizes the existing treatments for obesity and MAFLD that reduce the risk of developing T2DM.

Effects of 3021 meal replacement powder protect NAFLD via suppressing the ERS, oxidative stress and inflammatory responses

Objective

To explore the specific protective mechanism of 3021 meal replacement powder (MRP) against non-alcoholic fatty liver disease (NAFLD).

Materials and Methods

C57BL/6J male mice were divided into four groups: control group, 3021 MRP group, model group and test group. The lipid accumulation and endoplasmic reticulum stress (ERS)-related proteins in hepatocytes of mice were detected by hematoxylin-eosin (HE) staining, oil red O staining and Western blotting.

Results

The expressions of GRP78, GRP94, p-PERK and p-IRE1α were significantly inhibited in test group compared with those in model group. The protein expressions of p-NF-κB, p-JNK, IL-1β, IL-18 and NOX4 in test group were also significantly lower than those in model group. In vivo and in vitro experiments revealed that the body weight and lipid droplet content, and the expressions of ERS-related proteins (including BIP and XBP-1) in liver tissues all significantly declined in model group compared with those in 3021 MRP group.

Conclusion

In conclusion, 3021 MRP can greatly reduce lipid accumulation by inhibiting ERS, oxidative stress and inflammatory response in NAFLD.

Diagnostic Performance of 2D Shear Wave (2D-SWE) for Liver Fibrosis in Adults Undergoing Bariatric Surgery

BACKGROUND

Among the most recent methods to diagnose liver fibrosis is 2D shear wave elastography (2D-SWE). However, the evidence in the Latin population is limited, and there is no consensus on the cutoff points for each stage of fibrosis.

AIM

To evaluate the diagnostic performance of 2D-SWE for liver fibrosis in adults with obesity who underwent bariatric surgery (BS).

METHODS

We conducted a cross-sectional study on patients with obesity who underwent BS between 2020 and 2021. Liver stiffness measurement was reported as the mean of valid measurements in kilopascals made with the 2D-SWE. The outcome was biopsy-proven liver fibrosis. ROC curves were constructed for significant fibrosis (F≥2) and advanced fibrosis (F≥3), with their respective area under the curve (AUC). To obtain the best cutoff point for each scenario, we used the Youden index. The 95% confidence intervals (95% CI) for each cutoff point were estimated by bootstrap with 1000 replications.

RESULTS

We analyzed data from 227 patients. The mean age was 37.8 ± 11.1 years and 65.2% were women. Overall, the AUC for significant and advanced fibrosis was 0.54 (95% CI: 0.47-0.62) and 0.73 (95% CI: 0.60-0.87), respectively. For advanced fibrosis, higher AUCs were found among women (AUC: 0.82; 95% CI: 0.59-1.00) and among patients with morbid obesity (AUC: 0.78; 95% CI: 0.61-0.99).

CONCLUSION

The 2D-SWE appears to be a valuable tool for screening advanced liver fibrosis in candidates for BS, mainly in the female population and in adults with morbid obesity.

Weight Loss Improves Liver Dysfunction and Dipstick Proteinuria in Obesity: The Japan Specific Health Checkups Study

INTRODUCTION

Obesity and inappropriate lifestyle is the major risk factors for liver dysfunction and proteinuria. Nevertheless, previous studies have not described the differential impacts of body weight changes and lifestyle modification on already developed liver dysfunction and proteinuria.

METHODS

The original cohort was 933,490 individuals from the Japanese general population. In this investigation, we included 36,256 obese individuals with elevated levels of aspartate aminotransferase and/or alanine aminotransferase (≥31 IU/L) or positive proteinuria (+/- or more) in both the first and second years. Outcomes were the first normalization of these data defined as improvement in liver dysfunction and proteinuria. Times to outcomes were assessed using the Cox proportional hazards modeling for -1 kg/m2/year change in body mass index (BMI) changes in exercise and alcohol intake.

RESULTS

The multivariable-adjusted hazard ratio (HR) for incident improvement in liver dysfunction with BMI change -1.0 kg/m2/year was 1.07 (95% confidence interval [CI] 1.05-1.09) in obesity and that with improved proteinuria was 1.04 (95%CI 1.02-1.07). Compared to subjects without exercise habits, subjects who gained exercise habits exhibited a higher rate of improvement in liver dysfunction (HR 1.08; 95%CI 1.01-1.15) but not in proteinuria (HR 0.98; 95%CI 0.88-1.08). Compared to subjects with continuous alcohol intake habits, subjects who quit alcohol intake also showed a higher rate of improvement in liver dysfunction (HR 1.20; 95%CI 1.09-1.32).

CONCLUSIONS

This study suggested that weight loss greater than 1 kg/m2/year improves liver dysfunction and dipstick proteinuria in obesity. Particularly, liver dysfunction can be remedied by acquiring an exercise habit and quitting alcohol intake.

An updated meta-analysis of effects of curcumin on metabolic dysfunction-associated fatty liver disease based on available evidence from Iran and Thailand

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a common cause of chronic liver disease and can progress to nonalcoholic steatohepatitis and cirrhosis. This study aims to summarize the evidence for the effects of curcumin on MAFLD progression. Studies were identified from Medline and Scopus databases until April 2022. Systematic reviews and meta-analyses (SRMA) and randomized controlled trials (RCT) were selected based on pre-specified criteria. Three reviewers independently extracted data and assessed quality of included studies. Of the 427 identified records, 6 SRMAs and 16 RCTs were included in the analysis. Very high overlap was observed among SRMAs with corrected covered area of 21.9%. From an updated meta-analysis, curcumin demonstrated significant improvement in aspartate and alanine aminotransferase with pooled mean difference [95% confidence interval (CI)] of -3.90 (-5.97, -1.82) and -5.61 (-9.37, -1.85) units/L, respectively. Resolution and improvement of hepatic steatosis was higher in curcumin than control group with pooled relative risk (95% CI) of 3.53 (2.01, 6.22) and 3.41 (1.36, 8.56), respectively. Curcumin supplementation also led to lower fasting blood sugar, body mass index, and total cholesterol. Further trials should be conducted to assess the effect of curcumin on liver histology, especially regarding non-invasive hepatic fibrosis and steatosis.

Patients with NAFLD exhibit more advanced fibrosis in liver biopsy than patients with other chronic liver diseases

INTRODUCTION

Despite extremely high and seemingly rising prevalence of non-alcoholic fatty liver disease (NAFLD), awareness for this health condition is still low. In the present study we analyzed, if this is reflected in clinical routine for advanced diagnostic measures.

METHODS

Retrospective data of 93 patients with histologically determined fibrosis stage and confirmed etiology was analyzed. Patients were grouped according to chronic liver disease alone (n=40), concomitant chronic liver disease and NAFLD (n=29), or NAFLD alone (n=24). Fibrosis stage and presence of cirrhosis were main outcome measures.

RESULTS

Patients with NAFLD were significantly older and had significantly higher body mass index and CAP-values than patients with chronic liver disease. Significantly higher fibrosis stages were observed in patients with NAFLD than in those with chronic liver disease alone (p=0.003). Presence of cirrhosis was significantly higher in patients with NAFLD than in patients with chronic liver disease (p=0.01). This was not associated with a significantly different age distribution over fibrosis stages between chronic liver disease and NAFLD. Undergoing liver biopsy 10 years earlier could have possibly prevented progression to cirrhosis in up to 7 patients with NAFLD. This could have potentially saved 35,000 € yearly health care resources.

CONCLUSION

These findings suggest that the time course for development of liver fibrosis and cirrhosis is not fundamentally different between patients with NAFLD or with other chronic liver diseases. Higher rates of cirrhosis observed in patients with NAFLD could potentially be ameliorated by earlier diagnostic work-up and improved monitoring.

Endobariatrics: well past infancy and maturing rapidly

PURPOSE OF REVIEW

This review summarizes the key developments with regard to FDA-approved endoscopic bariatric metabolic therapies (EBMTs) in the last 2 years.

RECENT FINDINGS

The prevalence of obesity has increased during the coronavirus disease 2019 (COVID-19) pandemic, and obesity worsens COVID-19 related outcomes. Several studies have confirmed the safety and short-term efficacy of intragastric balloons (IGBs). In the short-term IGBs may improve steatosis and fibrosis in nonalcoholic fatty liver disease and improve quality of life and mental health. Unfortunately weight loss from these temporarily placed devices is not sustained long-term. Endoscopic sleeve gastroplasty (ESG) may be more effective and durable than IGBs, and result in fewer adverse events compared to bariatric surgery. The recently completed MERIT trial may catapult ESG as a first-line EBMT. Aspiration therapy meets safety and effectiveness thresholds for incorporation into routine practice, but overall acceptance has been lower than other FDA-approved EBMTs.

SUMMARY

The field of endobariatrics is rapidly maturing. Significant knowledge gaps remain with regards to combining EBMTs with pharmacologic therapy to improve durability of weight loss. The rapid expansion in the literature supporting safety and long-term efficacy ESG may prompt revision of existing guidelines.

The Impact of Bariatric-Surgery-Induced Weight Loss on Patients Undergoing Liver Transplant: A Focus on Metabolism, Pathophysiological Changes, and Outcome in Obese Patients Suffering NAFLD-Related Cirrhosis

Because of their condition, patients with morbid obesity develop several histopathological changes in the liver, such as non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), cirrhosis, and end-stage liver disease (ESLD). Hence, a liver transplant (LT) becomes an opportune solution for them. Due to many challenges during the perioperative and postoperative periods, these patients are recommended to lose weight before the surgery. There are many proposals to achieve this goal, such as intragastric balloons and many different bariatric surgery (BS) procedures in combination with a preparation diet (very-low-calorie diet, ketogenic diet, etc.). All the interventions focus on losing weight and keeping the continuity and functionality of the digestive tract to avoid postoperative complications. Thus, this review analyzes recent publications regarding the metabolic and pathophysiological impacts of BS in LT patients suffering from NAFLD-related cirrhosis, the effect of weight loss on postoperative complications, and exposes the cost-effectiveness of performing BS before, after, and at liver transplantation. Finally, the authors recommend BS before the LT since there are many positive effects and better outcomes for patients who lose weight before the procedure. Nevertheless, further multicentric studies are needed to determine the generalizability of these recommendations due to their impact on public health.

Physiopathology of nonalcoholic fatty liver disease: from diet to nutrigenomics

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide and is strongly associated with metabolic disorders, such as obesity, type 2 diabetes mellitus, and metabolic syndrome, to the extent that a new definition of metabolic associated fatty liver disease has been proposed.

RECENT FINDINGS

Insulin resistance, worsened by a high-fat and high-carbohydrate diet, is the key to the physiopathology of hepatic steatosis. This is driven by several mechanisms that are mostly activated at a genetic level, such as de-novo lipogenesis and triglyceride synthesis. Therefore, many diet regimens have been studied, although significant controversies remain regarding their metabolic effects and long-term sustainability.

SUMMARY

In this review, we summarized the role and effects of the main macronutrients on the development of NAFLD and discussed the molecular mechanisms involved. We also discussed the importance of genetic polymorphisms, epigenetic alterations, and dysbiosis to determine if lifestyle modification and a specific dietary regimen could be an essential part of NAFLD treatment.

Probiotics for the improvement of metabolic profiles in patients with metabolic-associated fatty liver disease: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

This meta-analysis of randomized controlled trials (RCTs) was conducted to assess the efficacy of probiotics in the treatment of metabolic-associated fatty liver disease (MAFLD) mainly in terms of liver function, glucose and lipid metabolism, and inflammation.

METHODS

RCTs were searched on PubMed, Web of Science, Embase, and the Cochrane Library until June 2022. A meta-analysis was performed on the therapeutic efficacy of probiotics on liver function, glucose and lipid metabolism, and inflammatory biomarkers by using RevMan 5.4 software.

RESULTS

A total of 772 patients from 15 studies were included in the analysis. The methodological quality varied across studies. We found that adding probiotic therapies could reduce the levels of alanine aminotransferase [mean difference (MD): -11.76 (-16.06, -7.46), p < 0.00001], aspartate aminotransferase (MD: -9.08 (-13.60, -4.56), p < 0.0001], γ-glutamyltransferase [MD: -5.67 (-6.80, -4.54), p < 0.00001] and homeostasis model assessment-insulin resistance [MD: -0.62 (-1.08, -0.15), p = 0.01], in patients with MAFLD compared with those in control individuals. However, there was no statistically significant improvement in the levels of total cholesterol, triglycerides, low-density lipoprotein cholesterol, C-reactive protein and tumor necrosis factor α among patients with MAFLD. Subgroup analyses showed that other key factors, such as age, participants' baseline body mass index, and the duration of intervention, may influence probiotic therapy outcomes.

CONCLUSION

There is promising evidence that probiotic supplementation can reduce liver enzyme levels and regulate glycometabolism in patients with MAFLD. Further rigorous and long-term trials exploring these novel therapeutic perspectives are warranted to confirm these results.

G Protein-Coupled Receptor GPR35 Suppresses Lipid Accumulation in Hepatocytes

Although prevalent, nonalcoholic fatty liver disease is not currently treated effectively with medicines. Initially, using wild-type and genome-edited clones of the human hepatocyte cell line HepG2, we show that activation of the orphan G protein-coupled receptor GPR35 is both able and sufficient to block liver X-receptor-mediated lipid accumulation. Studies on hepatocytes isolated from both wild-type and GPR35 knock-out mice were consistent with a similar effect of GPR35 agonists in these cells, but because of marked differences in the pharmacology of GPR35 agonists and antagonists at the mouse and human orthologues, as well as elevated basal lipid levels in hepatocytes from the GPR35 knock-out mice, no definitive conclusion could be reached. To overcome this, we generated and characterized a transgenic knock-in mouse line in which the corresponding human GPR35 splice variant replaced the mouse orthologue. In hepatocytes from these humanized GPR35 mice, activation of this receptor was shown conclusively to prevent, and also reverse, lipid accumulation induced by liver X-receptor stimulation. These studies highlight the potential to target GPR35 in the context of fatty liver diseases.