PPAR-γ-induced changes in visceral fat and adiponectin levels are associated with improvement of steatohepatitis in patients with NASH

Liver-based inter-organ communication: A disease perspective

Inter-organ communication through hormones, cytokines and extracellular vesicles (EVs) has emerged to contribute to the physiological states and pathological processes of the human body. Notably, the liver coordinates multiple tissues and organs to maintain homeostasis and maximize energy utilization, with the underlying mechanisms being unraveled in recent studies. Particularly, liver-derived EVs have been found to play a key role in regulating health and disease. As an endocrine organ, the liver has also been found to perform functions via the secretion of hepatokines. Investigating the multi-organ communication centered on the liver, especially in the manner of EVs and hepatokines, is of great importance to the diagnosis and treatment of liver-related diseases. This review summarizes the crosstalk between the liver and distant organs, including the brain, the bone, the adipose tissue and the intestine in noticeable situations. The discussion of these contents will add to a new dimension of organismal homeostasis and shed light on novel theranostics of pathologies.

Obesity and MASLD: Is weight loss the (only) key to treat metabolic liver disease?

Metabolic dysfunction-associated steatotic liver disease (MASLD) closely associates with obesity and type 2 diabetes. Lifestyle intervention and bariatric surgery aiming at substantial weight loss are cornerstones of MASLD treatment by improving histological outcomes and reducing risks of comorbidities. Originally developed as antihyperglycemic drugs, incretin (co-)agonists and SGLT2 inhibitors also reduce steatosis and cardiorenovascular events. Certain incretin agonists effectively improve histological features of MASLD, but not fibrosis. Of note, beneficial effects on MASLD may not necessarily require weight loss. Despite moderate weight gain, one PPARγ agonist improved adipose tissue and MASLD with certain benefit on fibrosis in post-hoc analyses. Likewise, the first THRβ-agonist was recently provisionally approved because of significant improvements of MASLD and fibrosis. We here discuss liver-related and metabolic effects induced by different MASLD treatments and their association with weight loss. Therefore, we compare results from clinical trials on drugs acting via weight loss (incretin (co)agonists, SGLT2 inhibitors) with those exerting no weight loss (pioglitazone; resmetirom). Furthermore, other drugs in development directly targeting hepatic lipid metabolism (lipogenesis inhibitors, FGF21 analogs) are addressed. Although THRβ-agonism may effectively improve hepatic outcomes, MASLD treatment concepts should consider all cardiometabolic risk factors for effective reduction of morbidity and mortality in the affected people.

Mediating effect of adiponectin between free fatty acid and tumor necrosis factor-α in patients with diabetes

BACKGROUND/OBJECTIVES

Increased free fatty acid (FFA) promotes adiponectin secretion in healthy subjects and induces inflammation in diabetes. Given the potential pro-inflammatory role of adiponectin in "adiponectin paradox", we performed this study in patients with type 2 diabetes mellitus (T2DM) to assess the association of FFA with adiponectin and to investigate whether adiponectin mediates FFA-related inflammation.

METHODS

This cross-sectional study consisted of adult patients with T2DM. FFA, adiponectin, and tumor necrosis factor-α (TNF-α) were assayed from fasting venous blood after overnight fasting for at least 8 h. Multivariable linear regression analysis and restricted cubic splines (RCS) analysis were performed to identify the association between FFA and adiponectin. Mediation analysis was performed to determine the mediating effect of adiponectin on the association between FFA and TNF-α.

RESULTS

This study included 495 participants, with 332 males (67.1%) and a mean age of 47.0 ± 11.2 years. FFA was positively associated with adiponectin (b = 0.126, 95%CI: 0.036-0.215, P = 0.006) and was the main contributor to the increase of adiponectin (standardized b = 0.141). The RCS analysis demonstrated that adiponectin increased with FFA when FFA was less than 0.7 mmol/L but did not further increase thereafter (Poverall < 0.001 and Pnon-linear < 0.001). In addition, adiponectin mediated the association between FFA and TNF-α. The mediating effect was 0.08 (95%CI: 0.03-0.13, P = 0.003) and the mediating effect percentage was 26.8% (95%CI: 4.5-49.2, P = 0.02).

CONCLUSIONS

In patients with T2DM, FFA was positively associated with adiponectin when FFA was less than 0.7 mmol/L. Elevated adiponectin mediated FFA-related inflammation. This study may provide insights into the pro-inflammatory effect of adiponectin in T2DM.

Synergistic effect of genistein and adiponectin reduces fat deposition in chicken hepatocytes by activating the ERβ-mediated SIRT1-AMPK signaling pathway

Dietary supplementation with bioactive substances that can regulate lipid metabolism is an effective approach for reducing excessive fat deposition in chickens. Genistein (GEN) has the potential to alleviate fat deposition; however, the underlying mechanism of GEN's fat-reduction action in chickens remains unclear. Therefore, the present study aimed to explore the underlying mechanism of GEN on the reduction of fat deposition from a novel perspective: intercellular transmission of adipokine between adipocytes and hepatocytes. The findings showed that GEN enhanced the secretion of adiponectin (APN) in chicken adipocytes, and the enhancement effect of GEN was completely blocked when the cells were pretreated with inhibitors targeting estrogen receptor β (ERβ) or proliferator-activated receptor γ (PPARγ) signals, respectively. Furthermore, the results demonstrated that both co-treatment with GEN and APN or treatment with the medium supernatant (Med SUP) derived from chicken adipocytes treated with GEN significantly decreased the content of triglyceride and increased the protein levels of ERβ, Sirtuin 1 (SIRT1) and phosphor-AMP-activated protein kinase (p-AMPK) in chicken hepatocytes compared to the cells treated with GEN or APN alone. Moreover, the increase in the protein levels of SIRT1 and p-AMPK induced by GEN and APN co-treatment or Med SUP treatment were blocked in chicken hepatocytes pretreated with the inhibitor of ERβ signals. Importantly, the up-regulatory effect of GEN and APN co-treatment or Med SUP treatment on the protein level of p-AMPK was also blocked in chicken hepatocytes pretreated with a SIRT1 inhibitor; however, the increase in the protein level of SIRT1 induced by GEN and APN co-treatment or Med SUP treatment was not reversed when the hepatocytes were pretreated with an AMPK inhibitor. In conclusion, the present study demonstrated that GEN enhanced APN secretion by activating the ERβ-Erk-PPARγ signaling pathway in chicken adipocytes. Subsequently, adipocyte-derived APN synergized with GEN to activate the ERβ-mediated SIRT1-AMPK signaling pathway in chicken hepatocytes, ultimately reducing fat deposition. These findings provide substantial evidence from a novel perspective, supporting the potential use of GEN as a dietary supplement to prevent excessive fat deposition in poultry.

MASLD/MASH and type 2 diabetes: Two sides of the same coin? From single PPAR to pan-PPAR agonists

Type 2 diabetes (T2D) and metabolic dysfunction-associated steatotic liver disease (MASLD), mainly related to nutrition and lack of physical activity, are both very common conditions, share several disease pathways and clinical manifestations, and increasingly co-occur with disease progression. Insulin resistance is an upstream node in the biology of both conditions and triggers liver parenchymal injury, inflammation and fibrosis. Peroxisome proliferator-activated receptor (PPAR) nuclear transcription factors are master regulators of energy homeostasis - insulin signaling in liver, adipose and skeletal muscle tissue - and affect immune and fibrogenesis pathways. Among distinct yet overlapping effects, PPARα regulates lipid metabolism and energy expenditure, PPARβ/δ has anti-inflammatory effects and increases glucose uptake by skeletal muscle, while PPARγ improves insulin sensitivity and exerts direct antifibrotic effects on hepatic stellate cells. Together PPARs thus represent pharmacological targets across the entire biology of MASH. Single PPAR agonists are approved for hypertriglyceridemia (PPARα) and T2D (PPARγ), but these, as well as dual PPAR agonists, have shown mixed results as anti-MASH treatments in clinical trials. Agonists of all three PPAR isoforms have the potential to improve the full disease spectrum from insulin resistance to fibrosis, and correspondingly to improve cardiometabolic and hepatic health, as has been shown (phase II data) with the pan-PPAR agonist lanifibranor.

The pan-PPAR agonist lanifibranor improves cardiometabolic health in patients with metabolic dysfunction-associated steatohepatitis

Lanifibranor, a pan-PPAR agonist, improves liver histology in patients with metabolic dysfunction-associated steatohepatitis (MASH), who have poor cardiometabolic health (CMH) and cardiovascular events as major mortality cause. NATIVE trial secondary and exploratory outcomes (ClinicalTrials.gov NCT03008070) were analyzed for the effect of lanifibranor on IR, lipid and glucose metabolism, systemic inflammation, blood pressure (BP), hepatic steatosis (imaging and histological grading) for all patients of the original analysis. With lanifibranor, triglycerides, HDL-C, apolipoproteins, insulin, HOMA-IR, HbA1c, fasting glucose (FG), hs-CRP, ferritin, diastolic BP and steatosis improved significantly, independent of diabetes status: most patients with prediabetes returned to normal FG levels. Significant adiponectin increases correlated with hepatic and CMH marker improvement; patients had an average weight gain of 2.5 kg, with 49% gaining ≥2.5% weight. Therapeutic benefits were similar regardless of weight change. Here, we show that effects of lanifibranor on liver histology in MASH are accompanied with CMH improvement, indicative of potential cardiovascular clinical benefits.

Epidemiology, screening, and co-management of type 2 diabetes mellitus and metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as NAFLD, is increasingly recognized as a prevalent global burden. Type 2 diabetes mellitus (T2DM), another important metabolic disease, is considered a major contributor to the development of MASLD. MASLD and T2DM have a strong association with each other due to shared pathogenic mechanisms. The co-existence of the 2 diseases increases the risk of liver-related adverse outcomes and imposes a heavier burden on extrahepatic outcomes, representing a substantial public health issue. Effective assessment and management of T2DM combined with MASLD necessitate a multidisciplinary approach. The emergence of numerous RCTs has shed light on the treatment of T2DM combined with MASLD. This review uncovers the epidemiology of the intertwined T2DM and MASLD, offers insights into the evaluation of hepatic fibrosis in patients with T2DM, glucose monitoring in the MASLD population, and provides comprehensive co-management strategies for addressing both diseases.

Hepatic glucose metabolism in the steatotic liver

The liver is central in regulating glucose homeostasis, being the major contributor to endogenous glucose production and the greatest reserve of glucose as glycogen. It is both a target and regulator of the action of glucoregulatory hormones. Hepatic metabolic functions are altered in and contribute to the highly prevalent steatotic liver disease (SLD), including metabolic dysfunction-associated SLD (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH). In this Review, we describe the dysregulation of hepatic glucose metabolism in MASLD and MASH and associated metabolic comorbidities, and how advances in techniques and models for the assessment of hepatic glucose fluxes in vivo have led to the identification of the mechanisms related to the alterations in glucose metabolism in MASLD and comorbidities. These fluxes can ultimately increase hepatic glucose production concomitantly with fat accumulation and alterations in the secretion and action of glucoregulatory hormones. No pharmacological treatment has yet been approved for MASLD or MASH, but some antihyperglycaemic drugs approved for treating type 2 diabetes have shown positive effects on hepatic glucose metabolism and hepatosteatosis. A deep understanding of how MASLD affects glucose metabolic fluxes and glucoregulatory hormones might assist in the early identification of at-risk individuals and the use or development of targeted therapies.

Comparison of the diagnostic effectiveness of ultrasound imaging coupled with three mathematical models for discriminating thyroid nodules

BACKGROUND

The overlapping nature of thyroid lesions visualized on ultrasound (US) images could result in misdiagnosis and missed diagnoses in clinical practice.

PURPOSE

To compare the diagnostic effectiveness of US coupled with three mathematical models, namely logistic regression (Logistics), partial least-squares discriminant analysis (PLS-DA), and support vector machine (SVM), in discriminating between malignant and benign thyroid nodules.

MATERIAL AND METHODS

A total of 588 thyroid nodules (287 benign and 301 malignant) were collected, among which 80% were utilized for constructing the mathematical models and the remaining 20% were used for internal validation. In addition, an external validation cohort comprising 160 nodules (80 benign and 80 malignant) was employed to validate the accuracy of these mathematical models.

RESULTS

Our study demonstrated that all three models exhibited effective predictive capabilities for distinguishing between benign and malignant nodules, whose diagnostic effectiveness surpassed that of the TI-RADS classification, particularly in terms of true negative diagnoses. SVM achieved a higher diagnostic rate for malignant thyroid nodules (93.8%) compared to Logistics (91.5%) and PLS-DA (91.6%). PLS-DA exhibited higher diagnostic rates for benign thyroid nodules (91.9%) compared to Logistics (86.7%) and SVM (88.7%). Both the area under the receiver operating characteristic curve (AUC) values of PLS-DA (0.917) and SVM (0.913) were higher than that of Logistics (0.891).

CONCLUSION

Our findings indicate that SVM had significantly higher rates of true positive diagnoses and PLS-DA exhibited significantly higher rates of true negative diagnoses. All three models outperformed the TI-RADS classification in discriminating between malignant and benign thyroid nodules.

Advancements in pharmacological treatment of NAFLD/MASLD: a focus on metabolic and liver-targeted interventions

In the present narrative review, we have summarized evidence on the pharmacological treatment of non-alcoholic fatty liver disease (NAFLD)/metabolic dysfunction-associated steatotic liver disease (MASLD). We start by reviewing the epidemiology of the condition and its close association with obesity and type 2 diabetes. We then discuss how randomized-controlled trials are performed following guidance from regulatory agencies, including differences and similarities between requirements of the US Food and Drug Administration and the European Medicine Agency. Difficulties and hurdles related to limitations of liver biopsy, a large number of screening failures in recruiting patients, as well as unpredictable response rates in the placebo group are evaluated. Finally, we recapitulate the strategies employed for potential drug treatments of this orphan condition. The first is to repurpose drugs that originally targeted T2DM and/or obesity, such as pioglitazone, glucagon-like peptide 1 receptor agonists (liraglutide and semaglutide), multi-agonists (tirzepatide and retatrutide), and sodium-glucose transporter 2 inhibitors. The second is to develop drugs specifically targeting NAFLD/MASLD. Among those, we focused on resmetirom, fibroblast growth factor 21 analogs, and lanifibranor, as they are currently in Phase 3 of their clinical trial development. While many failures have characterized the field of pharmacological treatment of NAFLD/MASLD in the past, it is likely that approval of the first treatments is near. As occurs in many chronic conditions, combination therapy might lead to better outcomes. In the case of non-alcoholic steatohepatitis, we speculate that drugs treating underlying metabolic co-morbidities might play a bigger role in the earlier stages of disease, while liver-targeting molecules will become vital in patients with more advanced disease in terms of inflammation and fibrosis.

Outcomes of Various Classes of Oral Antidiabetic Drugs on Nonalcoholic Fatty Liver Disease

Importance

Several oral antidiabetic drug (OAD) classes can potentially improve patient outcomes in nonalcoholic fatty liver disease (NAFLD) to varying degrees, but clinical data on which class is favored are lacking.

Objective

To investigate which OAD is associated with the best patient outcomes in NAFLD and type 2 diabetes (T2D).

Design, Setting, and Participants

This retrospective nonrandomized interventional cohort study used the National Health Information Database, which provided population-level data for Korea. This study involved patients with T2D and concomitant NAFLD.

Exposures

Receiving either sodium-glucose cotransporter 2 (SGLT2) inhibitors, thiazolidinediones, dipeptidyl peptidase-4 (DPP-4) inhibitors, or sulfonylureas, each combined with metformin for 80% or more of 90 consecutive days.

Main Outcomes and Measures

The main outcomes were NAFLD regression assessed by the fatty liver index and composite liver-related outcome (defined as liver-related hospitalization, liver-related mortality, liver transplant, and hepatocellular carcinoma) using the Fine-Gray model regarding competing risks.

Results

In total, 80 178 patients (mean [SD] age, 58.5 [11.9] years; 43 007 [53.6%] male) were followed up for 219 941 person-years, with 4102 patients experiencing NAFLD regression. When compared with sulfonylureas, SGLT2 inhibitors (adjusted subdistribution hazard ratio [ASHR], 1.99 [95% CI, 1.75-2.27]), thiazolidinediones (ASHR, 1.70 [95% CI, 1.41-2.05]), and DPP-4 inhibitors (ASHR, 1.45 [95% CI, 1.31-1.59]) were associated with NAFLD regression. SGLT2 inhibitors were associated with a higher likelihood of NAFLD regression when compared with thiazolidinediones (ASHR, 1.40 [95% CI, 1.12-1.75]) and DPP-4 inhibitors (ASHR, 1.45 [95% CI, 1.30-1.62]). Only SGLT2 inhibitors (ASHR, 0.37 [95% CI, 0.17-0.82]), not thiazolidinediones or DPP-4 inhibitors, were significantly associated with lower incidence rates of adverse liver-related outcomes when compared with sulfonylureas.

Conclusions and Relevance

The results of this cohort study suggest that physicians may lean towards prescribing SGLT2 inhibitors as the preferred OAD for individuals with NAFLD and T2D, considering their potential benefits in NAFLD regression and lower incidences of adverse liver-related outcomes. This observational study should prompt future research to determine whether prescribing practices might merit reexamination.

Therapeutic management of metabolic dysfunction associated steatotic liver disease

The incidence and prevalence of non-alcoholic fatty liver disease (NAFLD) have been steadily increasing worldwide, with a huge societal and economic burden. Recently, NAFLD and non-alcoholic steatohepatitis have been renamed and redefined as metabolic dysfunction associated steatotic liver disease (MASLD) and steatohepatitis (Metabolic Dysfunction Associated Steatohepatitis (MASH)), which result from an imbalance between metabolic and inflammatory stress (mainly as a consequence of adipose tissue dysfunction and insulin resistance) and the defence and repair mechanisms of the steatotic liver. Once MASLD progresses to end-stage of liver disease, treatment efficacy becomes limited and may require liver transplantation. Early detection and intervention are crucial. Lifestyle modification is consequently the cornerstone of its management. Timely consideration of bariatric surgeries should be given to patients meeting specific criteria. A multidisciplinary approach is warranted, starting from the concept that MASLD/MASH is at the centre of the cardiovascular-liver-metabolic syndrome. In some cases, pharmacological treatment can complement lifestyle modification. Several drugs used to treat the cardiometabolic co-morbidities have some potential efficacy in slowing Down disease progression, and some have demonstrated efficacy on histological endpoints that are likely to translate into long-term clinical benefits. Optimising the use of these drugs within their licenced indications is thus paramount for patients with MASLD. Several MASH-specific drugs are on the horizon and are likely to enrich our therapeutic armamentarium in the near future, particularly in non-cirrhotic stages of the disease. Much work still needs to be done to understand the specific features of MASH cirrhosis and develop efficacious treatments for this disease stage.

Drug targets regulate systemic metabolism and provide new horizons to treat nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH), is the advanced stage of nonalcoholic fatty liver disease (NAFLD) with rapidly rising global prevalence. It is featured with severe hepatocyte apoptosis, inflammation and hepatic lipogenesis. The drugs directly targeting the processes of steatosis, inflammation and fibrosis are currently under clinical investigation. Nevertheless, the long-term ineffectiveness and remarkable adverse effects are well documented, and new concepts are required to tackle with the root causes of NASH progression. We critically assess the recently validated drug targets that regulate the systemic metabolism to ameliorate NASH. Thermogenesis promoted by mitochondrial uncouplers restores systemic energy expenditure. Furthermore, regulation of mitochondrial proteases and proteins that are pivotal for intracellular metabolic homeostasis normalize mitochondrial function. Secreted proteins also improve systemic metabolism, and NASH is ameliorated by agonizing receptors of secreted proteins with small molecules. We analyze the drug design, the advantages and shortcomings of these novel drug candidates. Meanwhile, the structural modification of current NASH therapeutics significantly increased their selectivity, efficacy and safety. Furthermore, the arising CRISPR-Cas9 screen strategy on liver organoids has enabled the identification of new genes that mediate lipid metabolism, which may serve as promising drug targets. In summary, this article discusses the in-depth novel mechanisms and the multidisciplinary approaches, and they provide new horizons to treat NASH.

Pharmacological Approaches to Nonalcoholic Fatty Liver Disease: Current and Future Therapies

Nonalcoholic fatty liver disease (NAFLD) and its more severe form, nonalcoholic steatohepatitis (NASH), can promote the development of cirrhosis, hepatocellular carcinoma, cardiovascular disease, and type 2 diabetes. Similarly, type 2 diabetes confers the greatest risk for the development of NASH, especially when associated with obesity. Although lifestyle changes are critical to success, early implementation of pharmacological treatments for obesity and type 2 diabetes are essential to treat NASH and avoid disease progression. This article reviews current guidance regarding the use of pharmacological agents such as pioglitazone, glucagon-like peptide 1 receptor agonists, and sodium-glucose cotransporter 2 inhibitors in the setting of NAFLD and NASH. It also reviews the latest information on new drugs currently being investigated for the treatment of NASH.

Role of Insulin Resistance in the Development of Nonalcoholic Fatty Liver Disease in People With Type 2 Diabetes: From Bench to Patient Care

Insulin resistance is implicated in both the pathogenesis of nonalcoholic fatty liver disease (NAFLD) and its progression from steatosis to steatohepatitis, cirrhosis, and even hepatocellular carcinoma, which is known to be more common in people with type 2 diabetes. This article reviews the role of insulin resistance in the metabolic dysfunction observed in obesity, type 2 diabetes, atherogenic dyslipidemia, and hypertension and how it is a driver of the natural history of NAFLD by promoting glucotoxicity and lipotoxicity. The authors also review the genetic and environmental factors that stimulate steatohepatitis and fibrosis progression and their relationship with cardiovascular disease and summarize guidelines supporting the treatment of NAFLD with diabetes medications that reduce insulin resistance, such as pioglitazone or glucagon-like peptide 1 receptor agonists.

Therapeutic potential of adiponectin in prediabetes: strategies, challenges, and future directions

Adiponectin, an adipose-derived hormone, plays a pivotal role in glucose regulation and lipid metabolism, with a decrease in circulating adiponectin levels being linked to insulin resistance and prediabetes. This review examines the therapeutic potential of adiponectin in managing prediabetes, elucidating on multiple aspects including its role in glucose and lipid metabolism, influence on insulin sensitivity, and anti-inflammatory properties. Moreover, the paper highlights the latest strategies to augment adiponectin levels, such as gene therapy, pharmacological interventions, dietary modifications, and lifestyle changes. It also addresses the challenges encountered in translating preclinical findings into clinical practice, primarily related to drug delivery, safety, and efficacy. Lastly, the review proposes future directions, underlining the need for large-scale human trials, novel adiponectin analogs, and personalized treatment strategies to harness adiponectin's full therapeutic potential in preventing the transition from prediabetes to diabetes.

The role of anti-diabetic drugs in NAFLD. Have we found the Holy Grail? A narrative review

PURPOSE

Non-alcoholic fatty liver disease (NAFLD) has become a leading cause of liver disease, affecting 30% of the global population. NAFLD prevalence is particularly high in obese individuals and patients with type 2 diabetes mellitus (T2DM). NAFLD ranges from simple fat deposition in the liver to necroinflammation and fibrosis (non-alcoholic steatohepatitis (NASH)), NASH-cirrhosis, and/or hepatocellular carcinoma. Insulin resistance plays a key role in NAFLD pathogenesis, alongside dysregulation of adipocytes, mitochondrial dysfunction, genetic factors, and changes in gut microbiota. Since insulin resistance is also a major predisposing factor of T2DM, the administration of anti-diabetic drugs for the management of NAFLD seems reasonable.

METHODS

In this review we provide the NAFLD-associated mechanisms of action of some of the most widely used anti-diabetic drugs, namely metformin, pioglitazone, sodium-glucose transport protein-2 inhibitors (SGLT2i), glucagon-like peptide 1 receptor analogs (GLP1 RAs), and dipeptyl-peptidase-4 inhibitors (DPP4i) and present available data regarding their use in patients with NAFLD, with and without T2DM.

RESULTS

Both metformin and DPP4i have shown rather contradictory results, while pioglitazone seems to benefit patients with NASH and is thus the only drug approved for NASH with concomitant significant liver fibrosis by all major liver societies. On the other hand, SGLT2i and GLP1 RAs seem to be beneficiary in patients with NAFLD, showing both remarkable results, with SGLT2i proving to be more efficient in the only head-to-head study so far.

CONCLUSION

In patients with NAFLD and diabetes, pioglitazone, GLP1 RAs, and SGLT2i seem to be logical treatment options. Larger studies are needed before these drugs can be recommended for non-diabetic individuals.

Circulating hormones in biopsy-proven steatotic liver disease and steatohepatitis: A Multicenter Observational Study

BACKGROUND

The role of metabolic/inflammatory hormonal systems in metabolic dysfunction associated steatotic liver disease (MASLD) remains to be fully elucidated.

PURPOSE

To report the levels of the novel total and H-specific growth differentiation factor-15 (GDF-15) and other established hormonal systems and to describe hormonal patterns in controls and patients with MASLD and its stages.

METHODS

This is a multicenter study from two Gastroenterology-Hepatology Departments (Greece and Australia) and one Bariatric-Metabolic Surgery Department (Italy). Overall, n = 455 serum samples of patients with biopsy-proven MASLD (n = 374) and Controls (n = 81) were recruited.

RESULTS

We report for the first time that total and H-specific GDF-15 levels are higher in MASLD, at-risk metabolic dysfunction associated steatohepatitis (MASH), and severe fibrosis than in Controls. In addition, follistatin-like-3 (FSTL-3), free insulin-like growth factor-1 (IGF-1), leptin, and insulin levels were higher in MASLD patients than in Controls, while adiponectin levels were lower in MASLD subjects than in Controls. Activin-A, follistatin (FST), FSTL-3, and insulin levels significantly increased in severe fibrosis compared to no/mild fibrosis, while free IGF-1 decreased. In addition, adiponectin levels were lower in subjects without fibrosis vs. any fibrosis. Moreover, GDF-15 presented a strong positive association for the likelihood of having MASLD and at-risk MASH, while in adjusted analyses, FST and adiponectin showed inverse associations. Two different patterns of at-risk MASH were revealed through unsupervised analysis (total variation explained=54%). The most frequent pattern met in our sample (34.3%) was characterized by higher levels of total and H-specific GDF-15, follistatins, and activins, as well as low adiponectin levels. The second pattern revealed was characterized by high levels of free IGF-1, insulin, and leptin, with low levels of activin-A and adiponectin. Similar patterns were also generated in the case of overall MASLD.

CONCLUSIONS

Total and H-specific GDF-15 levels increase as MASLD severity progresses. FSTL-3, free IGF-1, leptin, and insulin are also higher, whereas adiponectin and activin-A levels are lower in the MASLD group than in Controls. Hormonal systems, including GDF-15, may not only be involved in the pathophysiology but could also prove useful for the diagnostic workup of MASLD and its stages and may potentially be of therapeutic value.

Treating NASH by targeting peroxisome proliferator-activated receptors

The pathophysiology of non-alcoholic steatohepatitis (NASH) encompasses a complex set of intra- and extrahepatic driving mechanisms, involving numerous metabolic, inflammatory, vascular and fibrogenic pathways. The peroxisome proliferator-activated receptors (PPARs) α, β/δ and γ belong to the nuclear receptor family of ligand-activated transcription factors. Activated PPARs modulate target tissue transcriptomic profiles, enabling the body's adaptation to changing nutritional, metabolic and inflammatory environments. PPARs hence regulate several pathways involved in NASH pathogenesis. Whereas single PPAR agonists exert robust anti-NASH activity in several preclinical models, their clinical effects on histological endpoints of NASH resolution and fibrosis regression appear more modest. Simultaneous activation of several PPAR isotypes across different organs and within-organ cell types, resulting in pleiotropic actions, enhances the therapeutic potential of PPAR agonists as pharmacological agents for NASH and NASH-related hepatic and extrahepatic morbidity, with some compounds having already shown clinical efficacy on histological endpoints.

Advances in Research on Type 2 Diabetes Mellitus Targets and Therapeutic Agents

Diabetes mellitus is a chronic multifaceted disease with multiple potential complications, the treatment of which can only delay and prolong the terminal stage of the disease, i.e., type 2 diabetes mellitus (T2DM). The World Health Organization predicts that diabetes will be the seventh leading cause of death by 2030. Although many antidiabetic medicines have been successfully developed in recent years, such as GLP-1 receptor agonists and SGLT-2 inhibitors, single-target drugs are gradually failing to meet the therapeutic requirements owing to the individual variability, diversity of pathogenesis, and organismal resistance. Therefore, there remains a need to investigate the pathogenesis of T2DM in more depth, identify multiple therapeutic targets, and provide improved glycemic control solutions. This review presents an overview of the mechanisms of action and the development of the latest therapeutic agents targeting T2DM in recent years. It also discusses emerging target-based therapies and new potential therapeutic targets that have emerged within the last three years. The aim of our review is to provide a theoretical basis for further advancement in targeted therapies for T2DM.

Nonalcoholic Fatty Liver Disease in Patients with Type 2 Diabetes: Screening, Diagnosis, and Treatment

Nonalcoholic fatty liver disease (NAFLD), recently renamed metabolic dysfunction-associated steatotic liver disease (MASLD) affects ~70% of patients with type 2 diabetes (T2D), with ~20% showing signs of advanced liver fibrosis. Patients with T2D are at an increased risk of developing cirrhosis, liver failure, and hepatocellular carcinoma and their liver-related mortality is doubled compared with non-diabetic individuals. Nonetheless, the condition is frequently overlooked and disease awareness is limited both among patients and among physicians. Given recent epidemiological evidence, clinical practice guidelines recommend screening for NAFLD/MASLD and advanced liver fibrosis in patients with T2D. While many drugs are currently being tested for the treatment of NAFLD/MASLD, none of them have yet received formal approval from regulatory agencies. However, several classes of antidiabetic drugs (namely pioglitazone, sodium-glucose transporter 2 inhibitors, glucagon-like peptide 1 receptor agonists, and multi-agonists) have shown favorable effects in terms of liver enzymes, liver fat content and, in some occasions, on histologic features such as inflammation and fibrosis. Therefore, diabetologists have the opportunity to actively treat NAFLD/MASLD, with a concrete possibility of changing the natural history of the disease. In the present narrative review, we summarize evidence and clinical recommendations for NAFLD/MAFLD screening in the setting of T2D, as well as on the effect of currently available glucose-lowering drugs on hepatic endpoints.

Current Therapeutical Approaches Targeting Lipid Metabolism in NAFLD

Nonalcoholic fatty liver disease (NAFLD, including nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH)) is a high-prevalence disorder, affecting about 1 billion people, which can evolve to more severe conditions like cirrhosis or hepatocellular carcinoma. NAFLD is often concomitant with conditions of the metabolic syndrome, such as central obesity and insulin-resistance, but a specific drug able to revert NAFL and prevent its evolution towards NASH is still lacking. With the liver being a key organ in metabolic processes, the potential therapeutic strategies are many, and range from directly targeting the lipid metabolism to the prevention of tissue inflammation. However, side effects have been reported for the drugs tested up to now. In this review, different approaches to the treatment of NAFLD are presented, including newer therapies and ongoing clinical trials. Particular focus is placed on the reverse cholesterol transport system and on the agonists for nuclear factors like PPAR and FXR, but also drugs initially developed for other conditions such as incretins and thyromimetics along with validated natural compounds that have anti-inflammatory potential. This work provides an overview of the different therapeutic strategies currently being tested for NAFLD, other than, or along with, the recommendation of weight loss.

Targeting lipid-sensing nuclear receptors PPAR (α, γ, β/δ): HTVS and molecular docking/dynamics analysis of pharmacological ligands as potential pan-PPAR agonists

The global prevalence of obesity-related systemic disorders, including non-alcoholic fatty liver disease (NAFLD), and cancers are rapidly rising. Several of these disorders involve peroxisome proliferator-activated receptors (PPARs) as one of the key cell signaling pathways. PPARs are nuclear receptors that play a central role in lipid metabolism and glucose homeostasis. They can activate or suppress the genes responsible for inflammation, adipogenesis, and energy balance, making them promising therapeutic targets for treating metabolic disorders. In this study, an attempt has been made to screen novel PPAR pan-agonists from the ZINC database targeting the three PPAR family of receptors (α, γ, β/δ), using molecular docking and molecular dynamics (MD) simulations. The top scoring five ligands with strong binding affinity against all the three PPAR isoforms were eprosartan, canagliflozin, pralatrexate, sacubitril, olaparib. The ADMET analysis was performed to assess the pharmacokinetic profile of the top 5 molecules. On the basis of ADMET analysis, the top ligand was subjected to MD simulations, and compared with lanifibranor (reference PPAR pan-agonist). Comparatively, the top-scoring ligand showed better protein-ligand complex (PLC) stability with all the PPARs (α, γ, β/δ). When experimentally tested in in vitro cell culture model of NAFLD, eprosartan showed dose dependent decrease in lipid accumulation and oxidative damage. These outcomes suggest potential PPAR pan-agonist molecules for further experimental validation and pharmacological development, towards treatment of PPAR-mediated metabolic disorders.

Special Population: Lean Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is strongly associated with obesity but around 10% to 20% of patients with NAFLD have normal body mass index, a condition referred to as lean or nonobese NAFLD. Although lean patients more often have milder liver disease, a proportion may nonetheless develop steatohepatitis and advanced liver fibrosis. Both genetic and environmental factors contribute to the development of NAFLD. Noninvasive tests have similarly good accuracy as initial assessments for lean NAFLD. Future studies should determine the most appropriate treatment in this special population.

Resveratrol and Dulaglutide ameliorate adiposity and liver dysfunction in rats with diet-induced metabolic syndrome: Role of SIRT-1 / adipokines / PPARγ and IGF-1

BACKGROUND

Adiposity and non-alcoholic fatty liver disease (NAFLD) are common characteristics of metabolic syndrome (MS). Understanding the underlying pathogenesis is crucial for the development of new remedies. Resveratrol controls obesity and glycemic disorders in patients with MS.

OBJECTIVES

This study aimed to evaluate the effect of resveratrol and dulaglutide on adipose tissues and liver in rats with MS, declaring their possible mechanisms.

METHODS

Rats allocated as Control, MS (induced by a high fat/ high sucrose diet for eight weeks), MS + Resveratrol (30 mg/kg/day orally), and MS + Dulaglutide (0.6 mg/kg twice weekly SC); drugs administration was in the last four weeks. Serum biochemical measurements were done. Liver and visceral fat were processed for biochemistry, histopathology, and immunohistochemistry.

RESULTS

MS results demonstrated significantly increased systolic and diastolic blood pressure, anthropometric measurements, serum levels of alanine aminotransferase (ALT), glycemic indices, and lipids with decreased HDL-C. Tissue levels of leptin, malondialdehyde (MDA), and TNF-α reactivity significantly increased. Expression of adiponectin, PPARγ, and insulin growth factor-1 (IGF-1) decreased. Also, Western blotting mRNA gene expression of liver SIRT-1 was down-regulated. Resveratrol and dulaglutide significantly and effectively reversed MS complexity, ameliorating all findings, particularly NAFLD and adiposity-induced inflammation. Resveratrol significantly appears superior to dulaglutide regarding the effects on hemodynamics, lipids, adipokines, IGF-1 levels, and adipocyte size. Parallel, dulaglutide has more influence on glycemic control.

CONCLUSION

Protective effects of the drugs may be through correlations between SIRT-1/adipokines/IGF-1 and PPARγ, improving the cross-talk between insulin resistance, obesity markers, liver dysfunction, and TNF-α. Promising multi-beneficial therapies of resveratrol or dulaglutide in MS are recommended clinically for this purpose. Showing the Experimental Design.

PPAR-γ signaling in nonalcoholic fatty liver disease: Pathogenesis and therapeutic targets

Non-alcoholic fatty liver disease (NAFLD), currently the leading cause of global chronic liver disease, has emerged as a major public health problem, more efficient therapeutics of which are thus urgently needed. Peroxisome proliferator-activated receptor γ (PPAR-γ), ligand-activated transcription factors of the nuclear hormone receptor superfamily, is considered a crucial metabolic regulator of hepatic lipid metabolism and inflammation. The role of PPAR-γ in the pathogenesis of NAFLD is gradually being recognized. Here, we outline the involvement of PPAR-γ in the pathogenesis of NAFLD through adipogenesis, insulin resistance, inflammation, oxidative stress, endoplasmic reticulum stress, and fibrosis. In addition, the evidence for PPAR-γ- targeted therapy for NAFLD are summarized. Altogether, PPAR-γ is a promising therapeutic target for NAFLD, and the development of drugs that can balance the beneficial and undesirable effects of PPAR-γ will bring new light to NAFLD patients.

Obesity, diabetes mellitus, and cardiometabolic risk: An Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) 2023

Background

This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) is intended to provide clinicians an overview of type 2 diabetes mellitus (T2DM), an obesity-related cardiometabolic risk factor.

Methods

The scientific support for this CPS is based upon published citations and clinical perspectives of OMA authors.

Results

Topics include T2DM and obesity as cardiometabolic risk factors, definitions of obesity and adiposopathy, and mechanisms for how obesity causes insulin resistance and beta cell dysfunction. Adipose tissue is an active immune and endocrine organ, whose adiposopathic obesity-mediated dysfunction contributes to metabolic abnormalities often encountered in clinical practice, including hyperglycemia (e.g., pre-diabetes mellitus and T2DM). The determination as to whether adiposopathy ultimately leads to clinical metabolic disease depends on crosstalk interactions and biometabolic responses of non-adipose tissue organs such as liver, muscle, pancreas, kidney, and brain.

Conclusions

This review is intended to assist clinicians in the care of patients with the disease of obesity and T2DM. This CPS provides a simplified overview of how obesity may cause insulin resistance, pre-diabetes, and T2DM. It also provides an algorithmic approach towards treatment of a patient with obesity and T2DM, with "treat obesity first" as a priority. Finally, treatment of obesity and T2DM might best focus upon therapies that not only improve the weight of patients, but also improve the health outcomes of patients (e.g., cardiovascular disease and cancer).

'Mistakes in managing non-alcoholic fatty liver disease and how to avoid them'

Non-alcoholic fatty liver disease (NAFLD) is the commonest cause of chronic liver disease. NAFLD is estimated to affect 25% of the global population. Therefore, it is widely encountered in primary care. A proportion of patients with NAFLD need a specialist referral, evaluation and follow-up.There have been many updated guidelines on the management of NAFLD in the past few years. Given the burden of NAFLD in the community and its cardiovascular and liver-related adverse outcomes, knowledge of evidence-based standards of care for these patients is essential for any practitioner managing patients with NAFLD. As an asymptomatic disease in the early stages, NAFLD can lead to many mistakes in its management.We aim to highlight some common mistakes in managing NAFLD and attempt to provide evidence-based recommendations.

Antioxidant and anti-inflammatory agents in chronic liver diseases: Molecular mechanisms and therapy

Chronic liver disease (CLD) is a continuous process that causes a reduction of liver function lasting more than six months. CLD includes alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD), chronic viral infection, and autoimmune hepatitis, which can lead to liver fibrosis, cirrhosis, and cancer. Liver inflammation and oxidative stress are commonly associated with the development and progression of CLD. Molecular signaling pathways such as AMP-activated protein kinase (AMPK), C-Jun N-terminal kinase, and peroxisome proliferator-activated receptors (PPARs) are implicated in the pathogenesis of CLD. Therefore, antioxidant and anti-inflammatory agents from natural products are new potent therapies for ALD, NAFLD, and hepatocellular carcinoma (HCC). In this review, we summarize some powerful products that can be potential applied in all the stages of CLD, from ALD/NAFLD to HCC. The selected agents such as β-sitosterol, curcumin, genistein, and silymarin can regulate the activation of several important molecules, including AMPK, Farnesoid X receptor, nuclear factor erythroid 2-related factor-2, PPARs, phosphatidylinositol-3-kinase, and lysyl oxidase-like proteins. In addition, clinical trials are undergoing to evaluate their efficacy and safety.

An adipocentric perspective on the development and progression of non-alcoholic fatty liver disease

Alongside the liver, white adipose tissue (WAT) is critical in regulating systemic energy homeostasis. Although each organ has its specialised functions, they must work coordinately to regulate whole-body metabolism. Adipose tissues and the liver are relatively resilient and can adapt to an energy surplus by facilitating triglyceride (TG) storage up to a certain threshold level without significant metabolic disturbances. However, lipid storage in WAT beyond a "personalised" adiposity threshold becomes dysfunctional, leading to metabolic inflexibility, progressive inflammation, and aberrant adipokine secretion. Moreover, the failure of adipose tissue to store and mobilise lipids results in systemic knock-on lipid overload, particularly in the liver. Factors contributing to hepatic lipid overload include lipids released from WAT, dietary fat intake, and enhanced de novo lipogenesis. In contrast, extrahepatic mechanisms counteracting toxic hepatic lipid overload entail coordinated compensation through oxidation of surplus fatty acids in brown adipose tissue and storage of fatty acids as TGs in WAT. Failure of these integrated homeostatic mechanisms leads to quantitative increases and qualitative alterations to the lipidome of the liver. Initially, hepatocytes preferentially accumulate TG species leading to a relatively "benign" non-alcoholic fatty liver. However, with time, inflammatory responses ensue, progressing into more severe conditions such as non-alcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma, in some individuals (often without an early prognostic clue). Herein, we highlight the pathogenic importance of obesity-induced "adipose tissue failure", resulting in decreased adipose tissue functionality (i.e. fat storage capacity and metabolic flexibility), in the development and progression of NAFL/NASH.

Liver transplantation for non-alcoholic fatty liver disease: indications and post-transplant management

Non-alcoholic fatty liver disease (NAFLD) is currently the fastest growing indication to liver transplantation (LT) in Western Countries, both for end stage liver disease and hepatocellular carcinoma. NAFLD/non-alcoholic steatohepatitis (NASH) is often expression of a systemic metabolic syndrome; therefore, NAFLD/NASH patients require a multidisciplinary approach for a proper pre-surgical evaluation, which is important to achieve a post-transplant outcome comparable to that of other indications to LT. NAFLD/NASH patients are also at higher risk of post-transplant cardiovascular events, diabetes, dyslipidemia, obesity, renal impairment and recurrent NASH. Lifestyle modifications, included diet and physical activity, are key to improve survival and quality of life after transplantation. A tailored immunosuppressive regimen may be proposed in selected patients. Development of new drugs for the treatment of recurrent NASH is awaited.

Approach to the Patient With Nonalcoholic Fatty Liver Disease

CONTEXT

Nonalcoholic fatty liver disease (NAFLD) is associated with obesity and type 2 diabetes (T2D), causing substantial burden from hepatic and extrahepatic complications. However, endocrinologists often follow people who are at the highest risk of its more severe form with nonalcoholic steatohepatitis or NASH (i.e., T2D or obesity with cardiometabolic risk factors). Endocrinologists are in a unique position to prevent cirrhosis in this population with early diagnosis and treatment.

OBJECTIVE

This work aims to offer endocrinologists a practical approach for the management of patients with NAFLD, including diagnosis, fibrosis risk stratification, and referral to hepatologists.

PATIENTS

(1) An asymptomatic patient with obesity and cardiometabolic risk factors, found to have hepatic steatosis; (2) a patient with T2D and NASH with clinically significant liver fibrosis; and (3) a liver transplant recipient with a history of NASH cirrhosis, with significant weight regain and with recurrent NAFLD on the transplanted organ.

CONCLUSION

NASH can be reversed with proper management of obesity and of T2D. While no agents are currently approved for the treatment of NASH, treatment should include lifestyle changes and a broader use of structured weight-loss programs, obesity pharmacotherapy, and bariatric surgery. Diabetes medications such as pioglitazone and some glucagon-like peptide 1 receptor agonists may also improve liver histology and cardiometabolic health. Sodium-glucose cotransporter-2 inhibitors and insulin may ameliorate steatosis, but their effect on steatohepatitis remains unclear. Awareness by endocrinologists about, establishing an early diagnosis of fibrosis (ie, FIB-4, liver elastography) in patients at high-risk of cirrhosis, long-term monitoring, and timely referral to the hepatologist are all critical to curve the looming epidemic of cirrhosis from NAFLD.

Response to pioglitazone in non-alcoholic fatty liver disease patients with vs. without type 2 diabetes: A meta-analysis of randomized controlled trials

BACKGROUND

Pioglitazone is considered a potential therapy for non-alcoholic fatty liver disease (NAFLD). However, different effects of pioglitazone on NAFLD have been demonstrated in diabetic and non-diabetic patients. Herein, a meta-analysis of randomized, placebo-controlled trials was carried out to indirectly compare pioglitazone in NAFLD patients with vs. without type 2 diabetes.

METHODS

Randomized controlled trials (RCTs) of pioglitazone vs. placebo involving NAFLD patients with or without type 2 diabetes/prediabetes collected from databases were enrolled into this analysis. Methodological quality was employed to evaluate the domains recommended by the Cochrane Collaboration. The analysis covered the changes in histology (fibrosis, hepatocellular ballooning, inflammation, steatosis), liver enzymes, blood lipids, fasting blood glucose (FBS), homeostasis model assessment-IR (HOMA-IR), weight and body mass index (BMI) before and after treatment, and adverse events.

RESULTS

The review covered seven articles, with 614 patients in total, of which three were non-diabetic RCTs. No difference was found in patients with vs. without type 2 diabetes in histology, liver enzymes, blood lipids, HOMA-IR, weight, BMI, and FBS. Moreover, no significant difference was revealed in adverse effects between NAFLD patients with diabetes and without DM, except the incidence of edema that was found to be higher in the pioglitazone group than in the placebo group in NAFLD patients with diabetes.

CONCLUSIONS

Pioglitazone could exert a certain effect on alleviating NAFLD, which was consistent between non-diabetic NAFLD patients and diabetic NAFLD patients in improving histopathology, liver enzymes, and HOMA-IR and reducing blood lipids. Furthermore, there were no adverse effects, except the incidence of edema which is higher in the pioglitazone group in NAFLD patients with diabetes. However, large sample sizes and well-designed RCTs are required to further confirm these conclusions.

Effects of Cilostazol on Angiogenesis in Diabetes through Adiponectin/Adiponectin Receptors/Sirtuin1 Signaling Pathway

Cilostazol is an antiplatelet agent with vasodilating effects that functions by increasing the intracellular concentration of cyclic adenosine monophosphate. We have previously shown that cilostazol has favorable effects on angiogenesis. However, there is no study to evaluate the effects of cilostazol on adiponectin. We investigated the effects of cilostazol on angiogenesis in diabetes in vitro and in vivo through adiponectin/adiponectin receptors (adipoRs) and the sirtuin 1 (SIRT1)/AMP-activated protein kinase (AMPK) signaling pathway. Human umbilical vein endothelial cells (HUVECs) and human aortic smooth muscle cells (HASMCs) were cocultured under high glucose (HG) conditions. Adiponectin concentrations in the supernatants were significantly increased when HASMCs were treated with cilostazol but not significantly changed when only HUVECs were treated with cilostazol. Cilostazol treatment enhanced the expression of SIRT1 and upregulated the phosphorylation of AMPK in HG-treated HUVECs. By sequential knockdown of adipoRs, SIRT1, and AMPK, our data demonstrated that cilostazol prevented apoptosis and stimulated proliferation, chemotactic motility, and capillary-like tube formation in HG-treated HUVECs through the adipoRs/SIRT1/AMPK signaling pathway. The phosphorylation of downstream signaling molecules, including acetyl-CoA carboxylase (ACC) and endothelial nitric oxide synthase (eNOS), was downregulated when HUVECs were treated with a SIRT1 inhibitor. In streptozotocin-induced diabetic mice, cilostazol treatment could improve blood flow recovery 21-28 days after inducing hindlimb ischemia as well as increase the circulating of CD34⁺CD45^dim cells 14-21 days after operation; moreover, these effects were significantly attenuated by the knockdown of adipoR1 but not adipoR2. The expression of SIRT1 and phosphorylation of AMPK/ACC and Akt/eNOS in ischemic muscles were significantly attenuated by the gene knockdown of adipoRs. Cilostazol improves HG-induced endothelial dysfunction in vascular endothelial cells and enhances angiogenesis in diabetic mice by upregulating the expression of adiponectin/adipoRs and its SIRT1/AMPK downstream signaling pathway.

Adipose Tissue Insulin Resistance Predicts the Severity of Liver Fibrosis in Patients with Type 2 Diabetes and NAFLD

CONTEXT

While T2D is a risk factor for liver fibrosis in NAFLD, the specific contribution of insulin resistance (IR) relative to other factors is unknown.

OBJECTIVE

Assess the impact on liver fibrosis in NAFLD of adipose tissue (Adipo-IR) and liver (HOMA-IR) IR in people with T2D and NAFLD.

DESIGN

Participants were screened by elastography in the outpatient clinics for hepatic steatosis and fibrosis, including routine metabolites, cytokeratin-18 (marker of hepatocyte apoptosis/steatohepatitis), and HOMA-IR/Adipo-IR.

SETTING

University ambulatory care practice.

PARTICIPANTS

483 participants with T2D.

INTERVENTION

Screening for steatosis and fibrosis with elastography.

MAIN OUTCOME MEASURES

Liver steatosis (CAP) and fibrosis (LSM) and measurements of IR (Adipo-IR, HOMA-IR) and fibrosis (cytokeratin-18).

RESULTS

Clinically significant liver fibrosis (stage F ≥ 2= LSM ≥8.0 kPa) was found in 11%, having more features of the metabolic syndrome, lower adiponectin, and higher AST, ALT, liver fat and cytokeratin-18 (p < 0.05-0.01). In multivariable analysis including just clinical variables (model 1), obesity (BMI) had the strongest association with fibrosis (OR: 2.56, CI:1.87-3.50; p < 0.01). When metabolic measurements and cytokeratin-18 were included (model 2), only BMI, AST and liver fat remained significant. When fibrosis stage was adjusted for BMI, AST, and steatosis (model 3), only adipo-IR remained strongly associated with fibrosis (OR: 1.51, CI:1.05-2.16; p = 0.03), but not BMI, hepatic IR or steatosis.

CONCLUSIONS

These findings pinpoint to the central role of dysfunctional, insulin-resistant adipose tissue to advanced fibrosis in T2D, beyond simply BMI or steatosis. The clinical implication is that targeting adipose tissue should be the priority of treatment in NAFLD.

Management of NAFLD in primary care settings

Non-alcoholic fatty liver disease (NAFLD) affects at least 25% of the general population and is an increasingly important cause of cirrhosis and hepatocellular carcinoma. Although it is the research focus of the hepatology field, it is clear that primary care physicians are seeing the majority of NAFLD patients and are in a pivotal position to provide quality care. In this article, we review the role of primary care in the management of NAFLD. NAFLD is common in patients with diabetes, obesity and other metabolic risk factors. Abdominal ultrasonography is the most commonly used method to diagnose fatty liver. Simple fibrosis scores have high negative predictive values in excluding advanced liver fibrosis and future liver-related events and can be used in primary care as initial evaluation. An abnormal result should be followed by subsequent workup or specialist referral. Primary care is the ideal setting to institute multidisciplinary care, especially the involvement of dietitians and physical activity trainers in lifestyle intervention, as well as initiating the discussion of bariatric surgery in patients with severe obesity. Although specific drug treatment for steatohepatitis would require a more precise diagnosis, metabolic drugs that improve both steatohepatitis and cardiovascular outcomes (e.g. glucagon-like peptide-1 receptor agonists) may be considered in patients with NAFLD.

Adipose tissue dysfunction and visceral fat are associated with hepatic insulin resistance and severity of NASH even in lean individuals

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) is a heterogeneous disorder, but the factors that determine this heterogeneity remain poorly understood. Adipose tissue dysfunction is causally linked to NAFLD since it causes intrahepatic triglyceride (IHTG) accumulation through increased hepatic lipid flow, due to insulin resistance and pro-inflammatory adipokines release. While many studies in NAFLD have looked at total adiposity (i.e. mainly subcutaneous fat, SC-AT), it is still unclear the possible impact of visceral fat (VF). Thus, we investigated how VF versus SC-AT was related to NAFLD severity in lean, overweight and obese individuals versus lean controls.

METHODS

Thirty-two non-diabetic NAFLD with liver biopsy (BMI 21.4-34.7 kg/m² ) and eight lean individuals (BMI 19.6-22.8 kg/m² ) were characterized for fat distribution (VF, SC-AT and IHTG by magnetic resonance imaging), lipolysis and insulin resistance by tracer infusion, free fatty acids (FFAs) and triglyceride (TAG) concentration and composition (by mass spectrometry).

RESULTS

Intrahepatic triglyceride was positively associated with lipolysis, adipose tissue insulin resistance (Adipo-IR), TAG concentrations, and increased saturated/unsaturated FFA ratio. Compared to controls VF was higher in NAFLD (including lean individuals), increased with fibrosis stage and associated with insulin resistance in liver, muscle and adipose tissue, increased lipolysis and decreased adiponectin levels. Collectively, our results suggest that VF accumulation, given its location close to the liver, is one of the major risk factors for NAFLD.

CONCLUSIONS

These findings propose VF as an early indicator of NAFLD progression independently of BMI, which may allow for evidence-based prevention and intervention strategies.

Association between lower plasma adiponectin levels and higher liver stiffness in type 2 diabetic individuals with nonalcoholic fatty liver disease: an observational cross-sectional study

PURPOSE

Little is known about the association between plasma adiponectin levels and nonalcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes mellitus (T2DM). We examined whether there is an association between lower plasma adiponectin levels and the presence/severity of NAFLD in people with T2DM.

METHODS

We cross-sectionally recruited 79 men with non-insulin-treated T2DM and no known liver diseases, who had consecutively attended our diabetes outpatient service over a 6-month period and who underwent both ultrasonography and Fibroscan-measured liver stiffness (LSM). Nine single nucleotide polymorphisms (PNPLA3 rs738409 and other genetic variants) associated with NAFLD were investigated.

RESULTS

Among the 79 participants included (mean age 67 ± 10 years, BMI 27.7 ± 4 kg/m²), 28 did not have NAFLD, 32 had steatosis alone, and 19 had NAFLD with coexisting significant fibrosis (LSM ≥ 7.0 kPa by Fibroscan®). Compared to those without NAFLD, patients with hepatic steatosis alone and those with hepatic steatosis and coexisting significant fibrosis had lower high-molecular-weight adiponectin levels (5.5 [IQR 2.3-7.6] vs. 2.4 [1.8-3.7] vs. 1.6 [1.0-2.9] µg/mL; p < 0.001). After adjustment for age, body mass index, insulin resistance, and the PNPLA3 rs738409 variant, lower plasma adiponectin levels were found to be associated with increased odds of both steatosis alone (adjusted-odds ratio [OR] 2.44, 95% CI 1.04-5.56, p = 0.042) and NAFLD with coexisting significant fibrosis (adjusted-OR 3.84, 95% CI 1.23-10.0, p = 0.020). Similar findings were observed after adjustment for the other eight genotyped NAFLD-related polymorphisms.

CONCLUSION

Lower plasma adiponectin levels are closely associated with the presence and severity of NAFLD in men with T2DM, pointing to a role of adiponectin in NAFLD development and progression.

Adipokines in Non-Alcoholic Fatty Liver Disease: Are We on the Road toward New Biomarkers and Therapeutic Targets?

Simple Summary

Non-alcoholic fatty liver disease (NAFLD) is an unmet medical need due to its increasingly high incidence, severe clinical consequences, and the absence of feasible diagnostic tools and effective drugs. This review summarizes the preclinical and clinical data on adipokines, cytokine-like hormones secreted by adipose tissue, and NAFLD. The aim is to establish the potential of adipokines as diagnostic and prognostic biomarkers, as well as their potential as therapeutic targets for NAFLD. The limitations of current research are also discussed, and future perspectives are outlined.

Abstract

Non-alcoholic fatty liver disease (NAFLD) has become the major cause of chronic hepatic illness and the leading indication for liver transplantation in the future decades. NAFLD is also commonly associated with other high-incident non-communicable diseases, such as cardiovascular complications, type 2 diabetes, and chronic kidney disease. Aggravating the socio-economic impact of this complex pathology, routinely feasible diagnostic methodologies and effective drugs for NAFLD management are unavailable. The pathophysiology of NAFLD, recently defined as metabolic associated fatty liver disease (MAFLD), is correlated with abnormal adipose tissue–liver axis communication because obesity-associated white adipose tissue (WAT) inflammation and metabolic dysfunction prompt hepatic insulin resistance (IR), lipid accumulation (steatosis), non-alcoholic steatohepatitis (NASH), and fibrosis. Accumulating evidence links adipokines, cytokine-like hormones secreted by adipose tissue that have immunometabolic activity, with NAFLD pathogenesis and progression; however, much uncertainty still exists. Here, the current knowledge on the roles of leptin, adiponectin, ghrelin, resistin, retinol-binding protein 4 (RBP4), visfatin, chemerin, and adipocyte fatty-acid-binding protein (AFABP) in NAFLD, taken from preclinical to clinical studies, is overviewed. The effect of therapeutic interventions on adipokines’ circulating levels are also covered. Finally, future directions to address the potential of adipokines as therapeutic targets and disease biomarkers for NAFLD are discussed.

A Quantitative Systems Pharmacology Model of Liver Lipid Metabolism for Investigation of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease is a metabolic and inflammatory disease that afflicts many people worldwide and presently has few treatment options. To enhance the preclinical to clinical translation and the design of early clinical trials for novel therapeutics, we developed a Quantitative Systems Pharmacology model of human hepatocyte lipid metabolism. The intended application of the model is for simulating anti-steatotic therapies for reversing fatty liver. We parameterized the model using literature data from humans with both normal and elevated liver fat. We assessed that the model construct was sufficient to generate a virtual population of NAFLD patients that matched relevant statistics of a published clinical cohort, and then validated the model response to treatment by simulating pioglitazone and diet intervention in the virtual population. Finally, a sensitivity analysis was performed to determine the best points of intervention for reducing hepatic steatosis. Analysis of the model suggests the most potent method for reducing hepatic steatosis is by limiting non-esterified fatty acid flux from the adipose to the liver.

Celecoxib-mediated attenuation of non-alcoholic steatohepatitis is potentially relevant to redistributing the expression of adiponectin receptors in rats

Pharmacological inhibition of cyclooxygenase-2 (COX-2) activity ameliorated the severity of non-alcoholic steatohepatitis (NASH) rats. It is not completely understood that the role of COX-2 inhibitor celecoxib on adiponectin receptors (Adipo-R1/R2) expression in different tissues in NASH rats. Sprague-Dawley male NASH rats induced by a high-fat diet (HFD) were administrated with or without celecoxib for 8 weeks. Biochemical parameters of liver function, glucose, and lipid metabolism, and the levels of adiponectin, tumor necrosis factor-alpha (TNF-α), prostaglandin E₂ (PGE₂) in the serum or liver were collected according to the standard protocols. The mRNA and protein levels of Adipo-R1, Adipo-R2, and COX-2 in the liver, muscle, and visceral fat were performed by quantitative real-time polymerase chain reaction (q-PCR) and Western blot analysis, respectively. The results showed that celecoxib ameliorated the various clinical indicators and pathological characteristics in the NASH rats, including body weight, liver function, liver index, and redox activities in serum and hepatic samples. The serum concentrations of adiponectin and TNF-α and PGE₂ were negatively correlated. As expected, these ameliorative effects of celecoxib were associated with the gene and protein levels up-regulation of Adipo-R1, Adipo-R2 in the liver and visceral fat tissues, and seeming to be compensatory down-regulation expression in muscle tissues (P <0.05). Additionally, COX-2 protein expression was negatively correlated with serum adiponectin levels, protein expression of adiponectin receptors from the liver and visceral fat, conversely, positively correlated with those from the muscle. Our current study demonstrate that celecoxib might effectively alleviate NASH rats in a unique manner closely relevant to redistributing the expression of adiponectin receptors in the liver, visceral fat, and muscle. However, the precise molecular mechanism needs further study.

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NASH is a watershed in the progression of NAFLD.

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Finding a therapy for NASH is in urgent need.

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Pharmacological inhibition of COX-2 activity ameliorated the severity of NASH.

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Low-dose celecoxib, a COX-2 inhibitor, can improve NASH by redistributing the expression of adiponectin receptors.

Breakthroughs in therapies for NASH and remaining challenges

Initially a condition that received limited recognition and whose clinical impact was controversial, non-alcoholic steatohepatitis (NASH) has become a leading cause of chronic liver disease. Although there are no approved therapies, major breakthroughs, which will be reviewed here, have paved the way for future therapeutic successes. The unmet medical need in NASH is no longer disputed, and progress in the understanding of its pathogenesis has resulted in the identification of many pharmacological targets. Key surrogate outcomes for therapeutic trials are now accepted by regulatory agencies, thus creating a path for drug registration. A set of non-invasive measurements enabled early-stage trials to be conducted expeditiously, thus providing early indications on the biological and possibly clinical actions of therapeutic candidates. This generated efficacy results for a number of highly promising compounds that are now in late-stage development. Intense research aimed at further improving the assessment of histological endpoints and in developing non-invasive predictive biomarkers is underway. This will help improve the design and feasibility of successful trials, ultimately providing patients with therapeutic options that can change the course of the disease.

Effects of Nigella sativa supplementation on blood concentration and mRNA expression of TNF-α, PPAR-γ and adiponectin, as major adipogenesis-related markers, in obese and overweight women: a crossover, randomised-controlled trial

Adipocyte expansion through adipogenesis can offset the adverse metabolic effects of obesity. Nigella sativa (NS) (black seed) oil is shown to have therapeutic features in the management of obesity. NS oil might have beneficial changes in obese populations through mediating serum levels of adipogenesis-related parameters and relative transcriptional gene-diet interactions (nutrigenomics), though no previous studies assessed this mechanism in overweight/obese participants. This study assessed the effects of NS oil supplements on blood concentration and mRNA expression levels of TNF-α, PPAR-γ and serum adiponectin and expression of AdipoR1, as major adipogenesis and obesity-related parameters, in overweight/obese women using a cross-over design. Eligible women were randomised to receive either NS oil supplements (2000 mg/d) or placebo. Two periods of interventions (8 weeks in each) were cross-changed by a 4-week washout period. An individualised diet plan without calorie deficits was given to participants to match their energy/macronutrient intakes. The Pkcross procedure and intention-to-treat analysis were performed using Stata. Cohen's d(d) was estimated to measure the magnitude of the effects. Forty-six participants were included. NS oil capsules reduced transcription levels ((d = -2·31), P < 0·001) and blood concentrations of TNF-α ((d = -0·29), P < 0·001). AdipoR1 expression (d = 2·24, P < 0·001) and serum adiponectin (d = 0·88, P < 0·001) showed a significant augmentation with a medium-high effect size, as did gene expression (d = 0·69, P < 0·001) and serum levels of PPAR-γ (d = 0·97, P < 0·001). There was a moderate but significant decrease in body weight (d = 0·6, P < 0·001). The present beneficial findings would provide strong information for future nutrigenomics/clinical trial studies assessing the role of NS in the management of obesity and other comorbidities.

American Association of Clinical Endocrinology Clinical Practice Guideline for the Diagnosis and Management of Nonalcoholic Fatty Liver Disease in Primary Care and Endocrinology Clinical Settings: Co-Sponsored by the American Association for the Study of Liver Diseases (AASLD)

OBJECTIVE

To provide evidence-based recommendations regarding the diagnosis and management of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) to endocrinologists, primary care clinicians, health care professionals, and other stakeholders.

METHODS

The American Association of Clinical Endocrinology conducted literature searches for relevant articles published from January 1, 2010, to November 15, 2021. A task force of medical experts developed evidence-based guideline recommendations based on a review of clinical evidence, expertise, and informal consensus, according to established American Association of Clinical Endocrinology protocol for guideline development.

RECOMMENDATION SUMMARY

This guideline includes 34 evidence-based clinical practice recommendations for the diagnosis and management of persons with NAFLD and/or NASH and contains 385 citations that inform the evidence base.

CONCLUSION

NAFLD is a major public health problem that will only worsen in the future, as it is closely linked to the epidemics of obesity and type 2 diabetes mellitus. Given this link, endocrinologists and primary care physicians are in an ideal position to identify persons at risk on to prevent the development of cirrhosis and comorbidities. While no U.S. Food and Drug Administration-approved medications to treat NAFLD are currently available, management can include lifestyle changes that promote an energy deficit leading to weight loss; consideration of weight loss medications, particularly glucagon-like peptide-1 receptor agonists; and bariatric surgery, for persons who have obesity, as well as some diabetes medications, such as pioglitazone and glucagon-like peptide-1 receptor agonists, for those with type 2 diabetes mellitus and NASH. Management should also promote cardiometabolic health and reduce the increased cardiovascular risk associated with this complex disease.

A global view of the interplay between non-alcoholic fatty liver disease and diabetes

Non-alcoholic fatty liver disease (NAFLD) has become an epidemic, much like other non-communicable diseases (NCDs), such as cancer, obesity, diabetes, and cardiovascular disease. The pathophysiology of NAFLD, particularly involving insulin resistance and subclinical inflammation, is not only closely linked to that of those NCDs but also to a severe course of the communicable disease COVID-19. Genetics alone cannot explain the large increase in the prevalence of NAFLD during the past 2 decades and the increase that is projected for the next decades. Impairment of glucose and lipid metabolic pathways, which has been propelled by the worldwide increase in the prevalence of obesity and type 2 diabetes, is most likely behind the increase in people with NAFLD. As the prevalence of NAFLD varies among subgroups of patients with diabetes and prediabetes identified by cluster analyses, stratification of people with diabetes and prediabetes by major pathological mechanistic pathways might improve the diagnosis of NAFLD and prediction of its progression. In this Review, we aim to understand how diabetes can affect the development of hepatic steatosis and its progression to advanced liver damage. First, we emphasise the extent to which NAFLD and diabetes jointly occur worldwide. Second, we address the major mechanisms that are involved in the pathogenesis of NAFLD and type 2 diabetes, and we discuss whether these mechanisms place NAFLD in an important position to better understand the pathogenesis of NCDs and communicable diseases, such as COVID-19. Third, we address whether this knowledge can be used for personalised treatment of NAFLD in the future. Finally, we discuss the current treatment strategies for people with type 2 diabetes and their effectiveness in treating the spectrum of hepatic diseases from simple steatosis to non-alcoholic steatohepatitis and hepatic fibrosis.

The advantages of physical exercise as a preventive strategy against NAFLD in postmenopausal women

BACKGROUND

The prevalence and severity of nonalcoholic fatty liver disease (NAFLD) increase in women after menopause. This narrative review discusses the causes and consequences of NAFLD in postmenopausal women and describes how physical activity can contribute to its prevention.

METHODS

The authors followed the narrative review method to perform a critical and objective analysis of the current knowledge on the topic. The Medical Subject Heading keywords 'physical exercise', 'menopause', 'hormone replacement therapy', 'estradiol' and 'NAFLD' were used to establish a conceptual framework. The databases used to collect relevant references included Medline and specialized high-impact journals.

RESULTS

Higher visceral adiposity, higher rate of lipolysis in adipose tissue after oestrogen drop and changes in the expression of housekeeping proteins involved in hepatic lipid management are observed in women after menopause, contributing to NAFLD. Excessive liver steatosis leads to hepatic insulin resistance, oxidative stress and inflammation, accelerating NAFLD progression. Physical activity brings beneficial effects against several postmenopausal-associated complications, including NAFLD progression. Aerobic and resistance exercises partially counteract alterations induced by metabolic syndrome in sedentary postmenopausal women, impacting NAFLD progression and severity.

CONCLUSIONS

With the increased global obesity epidemic in developing countries, NAFLD is becoming a severe problem with increased prevalence in women after menopause. Evidence shows that physical activity may delay NAFLD development and severity in postmenopausal women, although the prescription of age-appropriate physical activity programmes is advisable to assure the health benefits.

Efficacy of Off-Label Therapy for Non-alcoholic Fatty Liver Disease in Improving Non-invasive and Invasive Biomarkers: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

Objective

To evaluate the effects of vitamin E, pioglitazone, sodium-glucose cotransporter-2 (SGLT2) inhibitors, and glucagon-like peptide-1 (GLP-1) receptor agonists in patients with non-alcoholic fatty liver disease (NAFLD).

Design

A network meta-analysis.

Data Sources

PubMed, Embase, Cochrane Library, and Web of Science databases from their inception until September 1, 2021.

Eligibility Criteria for Selecting Studies

Randomized controlled trials (RCTs) comparing the effects of four different drugs in patients with NAFLD were included. All superiority, non-inferiority, phase II and III, non-blinded, single-blinded, and double-blinded trials were included. Interventions of interest included vitamin E (α-tocopherol and δ-tocotrienol), pioglitazone, three kinds of GLP-1 receptor agonists (liraglutide, semaglutide, and dulaglutide), four SGLT2 inhibitors (dapagliflozin, empagliflozin, ipragliflozin, and tofogliflozin), and comparisons of these different drugs, and placebos.

Main Outcome Measures

The outcome measures included changes in non-invasive tests [alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), controlled attenuation parameter (CAP), enhanced liver fibrosis (ELF) score, liver fat content (LFC), and keratin-18 (K-18)] and invasive tests [fibrosis score and resolution of non-alcoholic steatohepatitis (NASH)].

Results

Twenty-seven trials including 3,416 patients were eligible for inclusion in the study. Results refer to vitamin E, pioglitazone, GLP-1 receptor agonists, and SGLT2 inhibitors. First, placebos were used as a reference. δ-Tocotrienol was superior to placebo in decreasing the GGT level. Semaglutide, ipragliflozin, and pioglitazone induced a significantly higher decrease in the ALT level than a placebo. Semaglutide, pioglitazone, and dapagliflozin were superior to placebo in decreasing the AST level. Tofogliflozin and pioglitazone induced a significantly higher decrease in the K-18 level than a placebo. Liraglutide was superior to placebo in decreasing CAP. Liraglutide, pioglitazone, and vitamin E induced a significantly higher increase in resolution of NASH than a placebo. As for pairwise comparisons, semaglutide and pioglitazone were superior to liraglutide in decreasing the ALT level. Semaglutide induced a significantly higher decrease in the ALT level than dulaglutide. Semaglutide was obviously superior to empagliflozin, liraglutide, dulaglutide, and tofogliflozin in decreasing the AST level. Pioglitazone induced a significantly higher decrease in the GGT level than ipragliflozin. δ-Tocotrienol was superior to liraglutide in decreasing the GGT level. Tofogliflozin and pioglitazone induced a significantly higher decrease in the K-18 level than dulaglutide. Pioglitazone was superior to vitamin E in increasing the resolution of NASH. Furthermore, liraglutide treatment had the highest SUCRA ranking in decreasing CAP and ELF scores and increasing the resolution of NASH. Pioglitazone treatment had the highest SUCRA ranking in decreasing LFC and fibrosis scores. Tofogliflozin treatment had the highest SUCRA ranking in decreasing K-18, while dapagliflozin treatment had the highest SUCRA ranking in decreasing the GGT level. Semaglutide treatment had the highest SUCRA ranking in decreasing the levels of ALT and AST.

Conclusion

The network meta-analysis provided evidence for the efficacy of vitamin E, pioglitazone, SGLT2 inhibitors, and GLP-1 receptor agonists in treating patients with NAFLD. To find the best guide-level drugs, it is necessary to include more RCTs with these off-label drugs, so that patients and clinicians can make optimal decisions together.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero, identifier: CRD42021283129.