Role of thiazolidinediones, insulin sensitizers, in non-alcoholic fatty liver disease

A multicentre, double-blind, placebo-controlled, randomized, parallel comparison, phase 3 trial to evaluate the efficacy and safety of pioglitazone add-on therapy in type 2 diabetic patients treated with metformin and dapagliflozin

AIM

To investigate the efficacy and safety of pioglitazone compared to placebo when added to metformin plus dapagliflozin, a sodium-glucose cotransporter-2 (SGLT2) inhibitor, for patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

In a multicentre study, with a randomized, double-blind, placebo-controlled design, 249 Korean patients with T2DM suboptimally managed on metformin and dapagliflozin were assigned to receive either pioglitazone (15 mg daily) or placebo for 24 weeks, followed by a 24-week pioglitazone extension. Primary outcomes included changes in glycated haemoglobin (HbA1c), with secondary outcomes assessing insulin resistance, adiponectin levels, lipid profiles, liver enzymes, body weight and waist circumference.

RESULTS

Pioglitazone administration resulted in a significant reduction in HbA1c levels (from 7.80% ± 0.72% to 7.27% ± 0.82%) compared with placebo (from 7.79% ± 0.76% to 7.69% ± 0.86%, corrected mean difference: -0.42% ± 0.08%; p < 0.01) at 24 weeks. Additional benefits from pioglitazone treatment included enhanced insulin sensitivity, increased adiponectin levels, raised high-density lipoprotein cholesterol levels and reduced liver enzyme levels, resulting in improvement in nonalcoholic fatty liver disease liver fat score. Despite no serious adverse events in either group, pioglitazone therapy was modestly but significantly associated with weight gain and increased waist circumference.

CONCLUSIONS

Adjunctive pioglitazone treatment in T2DM inadequately controlled with metformin and dapagliflozin demonstrates considerable glycaemic improvement, metabolic benefits, and a low risk of hypoglycaemia. These advantages must be weighed against the potential for weight gain and increased waist circumference.

Disparate outcomes in Hispanic patients with metabolic dysfunction-associated steatotic liver disease/steatohepatitis and type 2 diabetes: Large cohort study

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH) are a growing health burden across a significant portion of the global patient population. However, these conditions seem to have disparate rates and outcomes between different ethnic populations. The combination of MASLD/MASH and type 2 diabetes increases the risk of hepatocellular carcinoma (HCC), and Hispanic patients experience the greatest burden, particularly those in South Texas.

AIM

To compare outcomes between Hispanic and non-Hispanic patients in the United States, while further focusing on the Hispanic population within Southeast Texas to determine whether the documented disparity in outcomes is a function of geographical circumstance or if there is a more widespread reason that all clinicians must account for in prognostic consideration.

METHODS

This cohort analysis was conducted with data obtained from TriNetX, LLC ("TriNetX"), a global federated health research network that provides access to deidentified medical records from healthcare organizations worldwide. Two cohort networks were used: University of Texas Medical Branch (UTMB) hospital and the United States national database collective to determine whether disparities were related to geographic regions, like Southeast Texas.

RESULTS

This study findings revealed Hispanics/Latinos have a statistically significant higher occurrence of HCC, type 2 diabetes mellitus, and liver fibrosis/cirrhosis in both the United States and the UTMB Hispanic/Latino groups. All-cause mortality in Hispanics/Latinos was lower within the United States group and not statistically elevated in the UTMB cohort.

CONCLUSION

This would appear to support that Hispanic patients in Southeast Texas are not uniquely affected compared to the national Hispanic population.

Afriplex GRTTM extract attenuates hepatic steatosis in an in vitro model of NAFLD

BACKGROUND

Currently, it is acknowledged that vitamin E, insulin sensitizers and anti-diabetic drugs are used to manage non-alcoholic fatty liver disease (NAFLD), however, these therapeutic interventions harbour adverse side effects. Pioglitazone, an anti-diabetic drug, is currently the most effective therapy to manage NAFLD. The use of natural medicines is widely embraced due to the lack of evidence of their negative side effects. Rooibos has been previously shown to decrease inflammation and oxidative stress in experimental models of diabetes, however, this is yet to be explored in a setting of NAFLD. This study was aimed at investigating the effects of an aspalathin-rich green rooibos extract (Afriplex GRTTM) against markers of hepatic oxidative stress, inflammation and apoptosis in an in vitro model of NAFLD.

METHODS

Oleic acid [1 mM] was used to induce hepatic steatosis in C3A liver cells. Thereafter, the therapeutic effect of Afriplex GRTTM, with or without pioglitazone, was determined by assessing its impact on cell viability, changes in mitochondrial membrane potential, intracellular lipid accumulation and the expression of genes and proteins (ChREBP, SREBF1, FASN, IRS1, SOD2, Caspase-3, GSTZ1, IRS1 and TNF-α) that are associated with the development of NAFLD.

RESULTS

Key findings showed that Afriplex GRTTM added to the medium alone or combined with pioglitazone, could effectively block hepatic lipid accumulation without inducing cytotoxicity in C3A liver cells exposed oleic acid. This positive outcome was consistent with effective regulation of genes involved in insulin signaling, as well as carbohydrate and lipid metabolism (IRS1, SREBF1 and ChREBP). Interestingly, in addition to reducing protein levels of an inflammatory marker (TNF-α), the Afriplex GRTTM could ameliorate oleic acid-induced hepatic steatotic damage by decreasing the protein expression of oxidative stress and apoptosis related markers such as GSTZ1 and caspase-3.

CONCLUSION

Afriplex GRTTM reduced hepatic steatosis in oleic acid induced C3A liver cells by modulating SREBF1, ChREBP and IRS-1 gene expression. The extract may also play a role in alleviating inflammation by reducing TNF-α expression, suggesting that additional experiments are required for its development as a suitable therapeutic option against NAFLD. Importantly, further research is needed to explore its antioxidant role in this model.

Exploring Promising Therapies for Non-Alcoholic Fatty Liver Disease: A ClinicalTrials.gov Analysis

Background

Non-alcoholic fatty liver disease (NAFLD) is a common disease and has been increasing in recent years. To date, no FDA-approved drug specifically targets NAFLD.

Methods

The terms "Non-alcoholic Fatty Liver Disease" and "NAFLD" were used in a search of ClinicalTrials.gov on August 24, 2023. Two evaluators independently examined the trials using predetermined eligibility criteria. Studies had to be interventional, NAFLD focused, in Phase IV, and completed to be eligible for this review.

Results

The ClinicalTrials.gov database was searched for trials examining pharmacotherapeutics in NAFLD. The search revealed 1364 trials, with 31 meeting the inclusion criteria. Out of these, 19 were finalized for evaluation. The dominant intervention model was Parallel. The most prevalent studies were in Korea (26.3%) and China (21.1%). The most common intervention was metformin (12.1%), with others like Exenatide and Pioglitazone accounting for 9.1%.

Conclusion

Therapeutics used to manage NAFLD are limited. However, various medications offer potential benefits. Further investigations are definitely warranted.

High-throughput Second-generation Sequencing Technology Assisted Diagnosis of Familial Partial Lipodystrophy (Type 2 Kobberling-Dunnigan Syndrome): A Case Report

BACKGROUND

Whole exome sequencing (WES) provides support for clinical diagnosis and treatment of genetically related diseases based on specific probe capture and high-throughput second-generation sequencing technology. Familial partial lipodystrophy 2 (FPLD2; OMIM # 151660) or type 2 Köbberling-Dunnigan syndrome with insulin resistance syndrome is uncommon in mainland China and elsewhere.

AIMS

We report the case in order to have a further understanding of FPLD2 or type 2 Kobberling- Dunnigan syndrome) with the assistance of WES and improve the clinical and genetic understanding and diagnosis of this disease.

CASE REPORT

A 30-year-old woman was admitted to the cadre department of our hospital at 14:00 on July 11, 2021, because of hyperglycemia, a rapid heart rate, and excessive sweating during pregnancy. An oral glucose tolerance test (OGTT) showed that insulin and C-peptide increased slowly after glucose stimulation, and the peak value was extended backward (Table 1). It was suggested that the patient had developed insulin antibodies, resulting in insulin resistance. Her clinical features and familial inheritance were consistent with FPLD2 (type 2 Kobberling-Dunnigan syndrome). The results of WES indicated that a heterozygous mutation occurred in exon 8 of the LMNA gene, because the base C at position 1444 was mutated into T during transcription. This mutation changed the amino acid position 482 of the encoded protein from Arg to Trp. Type 2 Kobberling- Dunnigan syndrome is associated with an LMNA gene mutation. According to the patient's clinical manifestations, hypoglycemic and lipid-lowering therapy is recommended.

CONCLUSION

WES can assist in the simultaneous clinical investigation or confirmation of FPLD2 and help identify diseases with similar clinical phenotypes. This case demonstrates that familial partial lipodystrophy is associated with an LMNA gene mutation on chromosome 1q21-22. This is one of the few cases of familial partial lipodystrophy diagnosed by WES.

An Overview of the Role of Peroxisome Proliferator-activated Receptors in Liver Diseases

Peroxisome proliferator-activated receptors (PPARs) are a superfamily of nuclear transcription receptors, consisting of PPARα, PPARγ, and PPARβ/δ, which are highly expressed in the liver. They control and modulate the expression of a large number of genes involved in metabolism and energy homeostasis, oxidative stress, inflammation, and even apoptosis in the liver. Therefore, they have critical roles in the pathophysiology of hepatic diseases. This review provides a general insight into the role of PPARs in liver diseases and some of their agonists in the clinic.

Restoration of lysosomal acidification rescues autophagy and metabolic dysfunction in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in the world. High levels of free fatty acids in the liver impair hepatic lysosomal acidification and reduce autophagic flux. We investigate whether restoration of lysosomal function in NAFLD recovers autophagic flux, mitochondrial function, and insulin sensitivity. Here, we report the synthesis of novel biodegradable acid-activated acidifying nanoparticles (acNPs) as a lysosome targeting treatment to restore lysosomal acidity and autophagy. The acNPs, composed of fluorinated polyesters, remain inactive at plasma pH, and only become activated in lysosomes after endocytosis. Specifically, they degrade at pH of ~6 characteristic of dysfunctional lysosomes, to further acidify and enhance the function of lysosomes. In established in vivo high fat diet mouse models of NAFLD, re-acidification of lysosomes via acNP treatment restores autophagy and mitochondria function to lean, healthy levels. This restoration, concurrent with reversal of fasting hyperglycemia and hepatic steatosis, indicates the potential use of acNPs as a first-in-kind therapeutic for NAFLD.

Roles of the peroxisome proliferator-activated receptors (PPARs) in the pathogenesis of nonalcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum of disease phenotypes which start with simple steatosis and lipid accumulation in the hepatocytes - a typical histological lesions characteristic. It may progress to non-alcoholic steatohepatitis (NASH) that is characterized by hepatic inflammation and/or fibrosis and subsequent onset of NAFLD-related cirrhosis and hepatocellular carcinoma (HCC). Due to the central role of the liver in metabolism, NAFLD is regarded as a result of and contribution to the metabolic abnormalities seen in the metabolic syndrome. Peroxisome proliferator-activated receptors (PPARs) has three subtypes, which govern the expression of genes responsible for energy metabolism, cellular development, inflammation, and differentiation. The agonists of PPARα, such as fenofibrate and clofibrate, have been used as lipid-lowering drugs in clinical practice. Thiazolidinediones (TZDs) - ligands of PPARγ, such as rosiglitazone and pioglitazone, are also used in the treatment of type 2 diabetes (T2D) with insulin resistance (IR). Increasing evidence suggests that PPARβ/δ agonists have potential therapeutic effects in improving insulin sensitivity and lipid metabolism disorders. In addition, PPARs ligands have been considered as potential therapeutic drugs for hypertension, atherosclerosis (AS) or diabetic nephropathy. Their crucial biological roles dictate the significance of PPARs-targeting in medical research and drug discovery. Here, it reviews the biological activities, ligand selectivity and biological functions of the PPARs family, and discusses the relationship between PPARs and the pathogenesis of NAFLD and metabolic syndrome. This will open new possibilities for PPARs application in medicine, and provide a new idea for the treatment of fatty liver and related diseases.

An Update on the Current and Emerging Use of Thiazolidinediones for Type 2 Diabetes

Guidelines have increasingly stressed the concept that adequate glycemic control is required to prevent or decrease the macro- and microvascular complications of type 2 diabetes mellitus (T2DM). PPAR-gamma agonists (“glitazones”) are no longer prioritized due to their effects on heart failure. However, the association between these drugs and innovative therapies could be a valuable tool to attenuate the risk factors of the metabolic syndrome. Glitazones are used for the treatment of diabetes and associated comorbidities. There is substantial scientific evidence demonstrating the effect of glitazones at a cardiometabolic level, as well as on hematological and neurological pathologies that point to their usefulness. The use of glitazones has always been controversial both for the type of patients who must take these drugs and for the side effects associated with them. Unfortunately, the recent guidelines do not include them among the preferred drugs for the treatment of hyperglycemia and rosiglitazone is out of the market in many countries due to an adverse cardiovascular risk profile. Even though real-life studies have proven otherwise, and their pleiotropic effects have been highlighted, they have been unable to achieve primacy in the choice of antihyperglycemic drugs. It would be appropriate to demonstrate the usefulness of pioglitazone and its therapeutic benefit with further cardiovascular safety studies.

Antrodia cinnamomea and its compound dehydroeburicoic acid attenuate nonalcoholic fatty liver disease by upregulating ALDH2 activity

ETHNOPHARMACOLOGICAL RELEVANCE

Nonalcoholic fatty liver disease (NAFLD) is a prevalent liver disease, but currently has no specific medication in clinic. Antrodia cinnamomea (AC) is a medicinal fungus and it has been shown that AC can inhibit high fat diet (HFD)-induced lipid deposition in mouse livers, but the effective monomer in AC and mechanism against NAFLD remain unclear. It has been reported that aldehyde dehydrogenase 2 (ALDH2) activation shows protective effects on NAFLD. Our previous study demonstrates that AC and its monomer dehydroeburicoic acid (DEA) can upregulate the ALDH2 activity on alcoholic fatty liver disease mouse model, but it is not clear whether the anti-NAFLD effects of AC and DEA are mediated by ALDH2.

AIM TO STUDY

To elucidate the active compound in AC against NAFLD, study whether ALDH2 mediates the anti-NAFLD effects of AC and its effective monomer.

MATERIALS AND METHODS

WT mice, ALDH2-/- mice and ALDH2-/- mice re-expressed ALDH2 by lentivirus were fed with a methionine-choline deficient (MCD) diet or high fat diet (HFD) to induce NAFLD, and AC at the different doses (200 and/or 500 mg/kg body weight per day) was administrated by gavage at the same time. Primary hepatocytes derived from WT and ALDH2-/-mice were stimulated by oleic acid (OA) to induce lipid deposition, and the cells were treated with AC or DEA in the meantime. Lentivirus-mediated ALDH2-KD or ALDH2-OE were used to knock down or overexpress ALDH2 expression in HepG2 cells, respectively. Finally, the effects of DEA against NAFLD as well as its effects on upregulating liver ALDH2 and removing the harmful aldehyde 4-hydroxynonenal (4-HNE) were studied in the MCD diet-induced NAFLD mouse model.

RESULTS

In WT mice fed with a MCD diet or HFD, AC administration reduced hepatic lipid accumulation, upregulated ALDH2 activity in mouse livers, decreased 4-HNE contents both in mouse livers and serum, inhibited lipogenesis, inflammation and oxidative stress and promoted fatty acid β-oxidation. These effects were abolished in ALDH2 KO mice but could be restored by re-expression of ALDH2 by lentivirus. In primary hepatocytes of WT mice, AC and DEA inhibited OA-induced lipid accumulation and triglyceride (TG) synthesis, promoting the β-oxidation of fatty acid in the meantime. However, these effects were lost in primary hepatocytes of ALDH2 KO mice. Moreover, the expression level of ALDH2 significantly affected the inhibitory effects of AC and DEA on OA-induced lipid deposition in HepG2 cells. The effects of AC and DEA on suppressing lipid deposition, inhibiting mitochondrial ROS levels, reducing TG synthesis, and promoting β-oxidation of fatty acid were all enhanced with the overexpression of ALDH2 and reduced with the knockdown of ALDH2 expression. DEA showed dose-dependent effects on inhibiting liver lipid deposition, elevating ALDH2 activity and reducing 4-HNE levels in the livers of MCD diet-induced NAFLD mice.

CONCLUSION

DEA is the effective compound in AC against NAFLD. The related anti-NAFLD mechanisms of AC and DEA were through upregulating ALDH2 expression and activity, thus enhancing the elimination of 4-HNE in the livers, and sequentially alleviating oxidative stress and inflammation, promoting fatty acid β-oxidation and decreasing lipogenesis.

In Vivo and Ex Vivo Evaluation of 1,3-Thiazolidine-2,4-Dione Derivatives as Euglycemic Agents

Thiazolidinediones (TZDs), used to treat type 2 diabetes mellitus, act as full agonists of the peroxisome proliferator-activated receptor gamma. Unfortunately, they produce adverse effects, including weight gain, hepatic toxicity, and heart failure. Our group previously reported the design, synthesis, in silico evaluation, and acute oral toxicity test of two TZD derivatives, compounds 40 (C40) and 81 (C81), characterized as category 5 and 4, respectively, under the Globally Harmonized System. The aim of this study was to determine whether C40, C81, and a new compound, C4, act as euglycemic and antioxidant agents in male Wistar rats with streptozotocin-induced diabetes. The animals were randomly divided into six groups (n = 7): the control, those with diabetes and untreated, and those with diabetes and treated with pioglitazone, C40, C81, or C4 (daily for 21 days). At the end of the experiment, tissue samples were collected to quantify the level of glucose, insulin, triglycerides, total cholesterol, and liver enzymes, as well as enzymatic and nonenzymatic antioxidant activity. C4, without a hypoglycemic effect, displayed the best antioxidant activity. Whereas C81 could only attenuate the elevated level of blood glucose, C40 generated euglycemia by the end of the treatment. All compounds produced a significant decrease in triglycerides.

The Cholesterol Metabolite Cholest-5-en-3-One Alleviates Hyperglycemia and Hyperinsulinemia in Obese (db/db) Mice

Dietary sterols are catabolized into various substances in the intestinal tract. Dietary 3-oxo derivatives of cholesterol and plant sterols (e.g., cholest-4-en-3-one and campest-5-en-3-one) have been shown to have anti-obesity effects. In this study, we tested whether feeding cholest-5-en-3-one (5-cholestenone), a cholesterol metabolite, to db/db mice protects them from obesity-associated metabolic disorders. In db/db mice, dietary 5-cholestenone significantly alleviated hepatomegaly and elevated serum triglyceride levels; however, the effect was not sufficient to improve hepatic steatosis and obesity. On the other hand, hyperglycemia and severe hyperinsulinemia in control db/db mice were markedly attenuated in 5-cholestenone-fed db/db mice. The production of inflammatory cytokines, such as monocyte chemoattractant protein-1, interleukin-6, and tumor necrosis factor-alpha (TNFα), was decreased, suggesting that the suppressive actions of 5-cholestenone were attributable to the alleviation of chronic inflammation in db/db mice. Additionally, 5-cholestenone showed an inhibitory effect on TNFα-induced nuclear factor kappa B (NFκB) activation in the NFκB luciferase gene reporter assay. These results suggest that obesity-induced abnormal glucose metabolism could be alleviated in 5-cholestenone-fed db/db mice by reducing the production of inflammatory cytokines through suppression of the NFκB signaling pathway.

Roles of hepatic atypical protein kinase C hyperactivity and hyperinsulinemia in insulin-resistant forms of obesity and type 2 diabetes mellitus

Diet-induced obesity, the metabolic syndrome, type 2 diabetes (DIO/MetS/T2DM), and their adverse sequelae have reached pandemic levels. In mice, DIO/MetS/T2DM initiation involves diet-dependent increases in lipids that activate hepatic atypical PKC (aPKC) and thereby increase lipogenic enzymes and proinflammatory cytokines. These or other hepatic aberrations, via adverse liver-to-muscle cross talk, rapidly impair postreceptor insulin signaling to glucose transport in muscle. The ensuing hyperinsulinemia further activates hepatic aPKC, which first blocks the ability of Akt to suppress gluconeogenic enzyme expression, and later impairs Akt activation, further increasing hepatic glucose production. Recent findings suggest that hepatic aPKC also increases a proteolytic enzyme that degrades insulin receptors. Fortunately, all hepatic aberrations and muscle impairments are prevented/reversed by inhibition or deficiency of hepatic aPKC. But, in the absence of treatment, hyperinsulinemia induces adverse events, some by using "spare receptors" to bypass receptor defects. Thus, in brain, hyperinsulinemia increases Aβ-plaque precursors and Alzheimer risk; in kidney, hyperinsulinemia activates the renin-angiotensin-adrenal axis, thus increasing vasoconstriction, sodium retention, and cardiovascular risk; and in liver, hyperinsulinemia increases lipogenesis, obesity, hepatosteatosis, hyperlipidemia, and cardiovascular risk. In summary, increases in hepatic aPKC are critically required for development of DIO/MetS/T2DM and its adverse sequelae, and therapeutic approaches that limit hepatic aPKC may be particularly effective.

Hypoglycemic Efficacy of Rh-aFGF Variants in Treatment of Diabetes in ZDF Rats

Acidic fibroblast growth factor (aFGF) is a promising regulator of glucose with no adverse effects of hypoglycemia. Previous researches revealed that aFGF mediated adipose tissue remodeling and insulin sensitivity. These findings supported rh-aFGF₁₃₅ would be used as a new candidate for the treatment of insulin resistance and type 2 diabetes. In this study, we aimed to investigate the hypoglycemic efficacy of recombinant human acidic fibroblast growth factor 135 (rh-aFGF₁₃₅) with low mitogenic in type 2 diabetic ZDF rats. ZDF rats were treated with rh-aFGF₁₃₅ at a daily dosage of 0.25 and 0.50 mg/kg by tail intravenous injection for 5 weeks. The blood glucose levels, oral glucose tolerance test, insulin tolerance test, HOMA-IR for insulin resistance, serum biochemical parameters, and the histopathological changes of adipose tissue, liver and other organs were detected at designed time point. The glucose uptake activity and anti-insulin resistance effect of rh-aFGF₁₃₅ were also detected in HepG2 cells. Results revealed that rh-aFGF₁₃₅ exhibited a better hypoglycemic effect compared with vehicle group and without the adverse effect of hypoglycemia in ZDF rats. Compared with vehicle group, rh-aFGF₁₃₅ significantly improved the situation of hyperglycemia and insulin resistance. Rh-aFGF₁₃₅ decreased ALT, AST, GSP, and FFA levels noticeably compared with vehicle control group (P < 0.01 or P < 0.001). After 5 weeks of treatment, high-dosage rh-aFGF₁₃₅ could remodel adipose tissue, and has no influence on other organs. H&E staining showed that rh-aFGF₁₃₅ reduced the size of adipocytes. In addition, rh-aFGF₁₃₅ may improve insulin resistance partly by increasing the protein expression of p-IRS-1 (human Ser 307). As a hypoglycemic drug for long-term treatment, rh-aFGF₁₃₅ would be a potentially safe candidate for the therapy of type 2 diabetes.

Exenatide ameliorates experimental non-alcoholic fatty liver in rats via suppression of toll-like receptor 4/NFκB signaling: Comparison to metformin

AIMS

Non-alcoholic fatty liver disease (NAFLD) is a common liver disease. This study aimed to evaluate the role of exenatide compared with metformin in halting the progression of fatty liver stimulated by a high-fat diet (HiFD) in rats.

MAIN METHODS

Thirty male Wistar rats were allocated into 6 groups, 5 rats per each group. Group I: maintained on normal diet (normal group) for fourteen weeks. The other five groups were kept on HiFD throughout the experiment, HiFD was administered beside pharmacological treatments/or vehicle. Group II: (NAFLD control group), group III: received metformin (60 mg/kg/day, P.O.), group IV-VI: received exenatide (10, 20, and 40 μg/kg/day, S.C.) respectively for 7 weeks. At the end of the therapeutic period, fasting blood glucose was determined, and body weight was registered. Rats were sacrificed, and blood samples were taken to measure serum insulin, lipids, and liver enzymes. The liver index and homeostasis model of insulin resistance (HOMA-IR) index were calculated. Further, livers were dissected for histopathological examination and Western blot analysis.

KEY FINDINGS

NAFLD control group showed hyperglycemia, hyperinsulinemia, increased liver enzymes, hypertriglyceridemia, elevated hepatic lipid peroxides, and inflammatory mediators (interlukin 6, nuclear factor-κB, tumor necrosis factor-α and Toll-like receptor4) in addition to hepatic fatty degeneration. In a dose-dependent manner, exenatide significantly improved most of the above mentioned markers in comparsion with NAFLD at P≤0.05.

SIGNIFICANCE

The current results suggest that exenatide is equivalent to metformin in controlling insulin resistance, body weight gain, improving liver function, suppressing inflammation, and attenuating NAFLD progression in male rats.

Ghrelin regulates adipose tissue metabolism: Role in hepatic steatosis

Fatty liver is the earliest and most common response of the liver to consumption of excessive alcohol. Steatosis can predispose the fatty liver to develop progressive liver damage. Chief among the many mechanisms involved in development of hepatic steatosis is dysregulation of insulin-mediated adipose tissue metabolism. Particularly, it is the enhanced adipose lipolysis-derived free fatty acids and their delivery to the liver that ultimately results in hepatic steatosis. The adipose-liver axis is modulated by hormones, particularly insulin and adiponectin. In recent studies, we demonstrated that an alcohol-induced increase in serum ghrelin levels impairs insulin secretion from pancreatic β-cells. The consequent reduction in circulating insulin levels promotes adipose lipolysis and mobilization of fatty acids to the liver to ultimately contribute to hepatic steatosis. Because many tissues, including adipose tissue, express ghrelin receptor we hypothesized that ghrelin may directly affect energy metabolism in adipocytes. We have exciting new preliminary data which shows that treatment of premature 3T3-L1 adipocytes with ghrelin impairs adipocyte differentiation and inhibits lipid accumulation in the tissue designed to store energy in the form of fat. We further observed that ghrelin treatment of differentiated adipocytes significantly inhibited secretion of adiponectin, a hepatoprotective hormone that reduces lipid synthesis and promotes lipid oxidation. These results were corroborated by our observations of a significant increase in serum adiponectin levels in ethanol-fed rats treated with a ghrelin receptor antagonist verses the un-treated ethanol-fed rats. Interestingly, in adipocytes, ghrelin also increases secretion of interleukin-6 (IL-6) and CCL2 (chemokine [C-C motif] ligand 2), cytokines which promote hepatic inflammation and progression of liver disease. To summarize, the alcohol-induced increase in serum ghrelin levels dysregulates adipose-liver interaction and promotes hepatic steatosis by increasing the free fatty acid released from adipose for hepatic uptake, and by altering adiponectin and cytokine secretion. Taken together, our data indicates that targeting the activity of ghrelin may be a powerful treatment strategy.

Anti-Diabetic Medications for the Pharmacologic Management of NAFLD

As a chronic disease encompassing a wide spectrum of liver-related histologic damage, nonalcoholic fatty liver disease (NAFLD) is becoming a global epidemic with significant impacts on all-cause morbidity and mortality. Insulin resistance and type 2 diabetes mellitus predispose individuals to NAFLD and related complications. Therefore, timely intervention with anti-diabetic medications may prevent and delay the development of NAFLD or have a therapeutic implication. The focus of this review is to evaluate the evidence supporting the efficacy of anti-diabetic medications in the treatment of NAFLD. While many of these anti-diabetic agents have shown to improve biochemical parameters, their effect on hepatic histology is limited. Among anti-diabetic medications, only thiazolidinediones and glucagon-like peptide-1 receptor agonists demonstrate significant improvement in hepatic histology.

Targeting energy metabolism via the mitochondrial pyruvate carrier as a novel approach to attenuate neurodegeneration

Several molecular pathways are currently being targeted in attempts to develop disease-modifying therapies to slow down neurodegeneration in Parkinson’s disease. Failure of cellular energy metabolism has long been implicated in sporadic Parkinson’s disease and recent research on rare inherited forms of Parkinson’s disease have added further weight to the importance of energy metabolism in the disease pathogenesis. There exists a new class of anti-diabetic insulin sensitizers in development that inhibit the mitochondrial pyruvate carrier (MPC), a protein which mediates the import of pyruvate across the inner membrane of mitochondria. Pharmacological inhibition of the MPC was recently found to be strongly neuroprotective in multiple neurotoxin-based and genetic models of neurodegeneration which are relevant to Parkinson’s disease. In this review, we summarize the neuroprotective effects of MPC inhibition and discuss the potential putative underlying mechanisms. These mechanisms involve augmentation of autophagy via attenuation of the activity of the mammalian target of rapamycin (mTOR) in neurons, as well as the inhibition of neuroinflammation, which is at least partly mediated by direct inhibition of MPC in glia cells. We conclude that MPC is a novel and potentially powerful therapeutic target that warrants further study in attempts to slow Parkinson’s disease progression.

Phenotypic Alteration of Hepatocytes in Non-Alcoholic Fatty Liver Disease

Non-Alcoholic Fatty Liver Disease (NAFLD) has been recognized as the most common liver disorder in developed countries. NAFLD progresses from fat accumulation in hepatocytes to steatohepatitis to further stages of fibrosis and cirrhosis. Simple steatosis, i.e. fat deposition in the liver, is considered benign and gives way to non-alcoholic steatohepatitis (NASH) with a higher probability of progressing to cirrhosis, and liver-related mortality. Evidence has been found that this progression has been associated with marked alterations in hepatocyte histology and a shift in marker expression of healthy hepatocytes including increased expression of peroxisome proliferator-activated receptor gamma (PPARγ), adipocyte protein (aP2), CD36, interleukin-6 (IL-6), interleukin-18 (IL-18) and adiponectin. This progression shares much in common with the obesity phenotype, which involves a transformation of adipocytes from small, healthy cells to large, dysfunctional ones that contribute to redox imbalance and the progression of metabolic syndrome. Further, activation of Src/ERK signaling via the sodium potassium adenosine triphosphatase (Na/K-ATPase) α-1 subunit in impaired hepatocytes may contribute to redox imbalance, exacerbating the progression of NAFLD. This review hypothesizes that an adipogenic transformation of hepatocytes propagates redox imbalance and that the processes occurring in adipogenesis become activated in fat-laden hepatocytes in liver, thereby driving progression to NAFLD. Further, this review discusses therapeutic interventions to reverse NAFLD including the thiazolidinediones (TZDs) and a variety of antioxidant species. The peptide, pNaKtide, which is an antagonist of Na/K-ATPase signaling, is also proposed as a potential pharmacologic option for reducing reactive oxygen species (ROS) and reversing NAFLD by inhibiting the Na/K-ATPase-modulated ROS amplification loop.

Altered pharmacokinetics of rosiglitazone in a mouse model of non-alcoholic fatty liver disease

BACKGROUND

Severe forms of non-alcoholic fatty liver disease (NAFLD) adversely affect the liver physiology and hence the pharmacokinetics of drugs. Here, we investigated the effect of NAFLD on the pharmacokinetics of rosiglitazone, an insulin sensitizer used in the treatment of type 2 diabetes.

METHODS

Male C57BL/6 mice were divided into two groups. The first group (n=14) was fed with normal chow feed and the second group (n=14) was fed with 60% high-fat diet (HFD) and 40% high fructose liquid (HFL) for 60 days to induce NAFLD. The development of NAFLD was confirmed by histopathology, liver triglyceride levels and biochemical estimations, and used for pharmacokinetic investigations. Rosiglitazone was administered orally at 30 mg/kg dose. At predetermined time points, blood was collected and rosiglitazone concentrations were determined using LC/MS/MS. Plasma concentrations were subjected to non-compartmental analysis using Phoenix WinNonlin (6.3), and the area under the plasma concentration-time curve (AUC) was calculated by the linear-up log-down method.

RESULTS

HFD and HFL diet successfully induced NAFLD in mice. Rosiglitazone pharmacokinetics in NAFLD animals were altered significantly as compared to healthy mice. Rosiglitazone exposure increased significantly in NAFLD mice (2.5-fold higher AUC than healthy mice). The rosiglitazone oral clearance was significantly lower and the mean plasma half-life was significantly longer in NAFLD mice as compared to healthy mice.

CONCLUSIONS

The NAFLD mouse model showed profound effects on rosiglitazone pharmacokinetics. The magnitude of change in rosiglitazone pharmacokinetics is similar to that observed in humans with moderate to severe liver disease. The present animal model can be utilized to study the NAFLD-induced changes in the pharmacokinetics of different drugs.

Effect of Mediterranean Diet and Antioxidant Formulation in Non-Alcoholic Fatty Liver Disease: A Randomized Study

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide, characterized by liver fatty acid accumulation and fibrosis, not due to excessive alcohol consumption. Notably, nutritional habits have been reported to be implicated in the onset and severity of the hepatic damage, while the Mediterranean diet has shown beneficial effects on NAFLD. Free radicals and oxidative stress were suggested to be involved in the pathogenesis and progression of NAFLD, and several data highlighted the efficacy of antioxidant supplementation in its treatment. The aim of this study was to compare the effects of the Mediterranean diet, with or without an antioxidant complex supplement, in overweight patients suffering from NAFLD. In this prospective study, fifty Caucasian overweight patients were randomized into three groups (Groups A-C). A personalized moderately hypocaloric Mediterranean diet was prescribed to all patients included in the A and B groups. In addition to the diet, Group B was administered antioxidant supplementation daily and for the period of six months. Group C did not have any type of treatment. The study proved that the Mediterranean diet alone or in association with the antioxidant complex improved anthropometric parameters, lipid profile and reduced hepatic fat accumulation and liver stiffness. However, Group B patients, in which the diet was associated with antioxidant intake, showed not only a significant improvement in insulin sensitivity, but also a more consistent reduction of anthropometric parameters when compared with Group A patients. Taken together, these results support the benefit of antioxidant supplementation in overweight patients with NAFLD.

Level of dietary energy and 2,4-thiazolidinedione alter molecular and systemic biomarkers of inflammation and liver function in Holstein cows

Background

The objective of the study was to evaluate the effect of overfeeding a moderate energy diet and a 2,4-thiazolidinedione (TZD) injection on blood and hepatic tissue biomarkers of lipid metabolism, oxidative stress, and inflammation as it relates to insulin sensitivity.

Results

Fourteen dry non-pregnant cows were fed a control (CON) diet to meet 100% of NRC requirements for 3 wk, after which half of the cows were assigned to a moderate-energy diet (OVE) and half of the cows continued on CON for 6 wk. All cows received an intravenous injection of 4 mg TZD/kg of body weight (BW) daily from 2 wk after initiation of dietary treatments and for 2 additional week. Compared with CON cows and before TZD treatment, the OVE cows had lower concentration of total protein, urea and albumin over time. The concentration of cholesterol and tocopherol was greater after 2 wk of TZD regardless of diet. Before and after TZD, the OVE cows had greater concentrations of AST/GOT, while concentrations of paraoxonase, total protein, globulin, myeloperoxidase, and haptoglobin were lower compared with CON cows. Regardless of diet, TZD administration increased the concentration of ceruloplasmin, ROMt, cholesterol, tocopherol, total protein, globulin, myeloperoxidase and beta-carotene. In contrast, the concentration of haptoglobin decreased at the end of TZD injection regardless of diet. Prior to TZD injection, the mRNA expression of PC, ANGPTL4, FGF21, INSR, ACOX1, and PPARD in liver of OVE cows was lower compared with CON cows. In contrast, the expression of HMGCS2 was greater in OVE compared with CON cows. After 1 wk of TZD administration the expression of IRS1 decreased regardless of diet; whereas, expression of INSR increased after 2 wk of TZD injection. Cows fed OVE had lower overall expression of TNF, INSR, PC, ACOX1, FGF21, and PPARD but greater HMGCS2 expression. These differences were most evident before and after 1 wk of TZD injection, and by 2 wk of TZD differences in expression for most genes disappeared.

Conclusions

Based on molecular and blood data, administration of TZD enhanced some aspects of insulin sensitivity while causing contradictory results in terms of inflammation and oxidative stress. The bovine liver is TZD-responsive and level of dietary energy can modify the effects of TZD. Because insulin sensitizers have been proposed as useful tools to manage dairy cows during the transition period, further studies are required to investigate the potential hepatotoxicity effect of TZD (or similar compounds) in dairy cattle.

Electronic supplementary material

The online version of this article (doi:10.1186/s40104-017-0196-y) contains supplementary material, which is available to authorized users.

Consensus Statement on Dose Modifications of Antidiabetic Agents in Patients with Hepatic Impairment

Liver disease is an important cause of mortality in type 2 diabetes mellitus (T2DM). It is estimated that diabetes is the most common cause of liver disease in the United States. Virtually, entire spectrum of liver disease is seen in T2DM including abnormal liver enzymes, nonalcoholic fatty liver disease, cirrhosis, hepatocellular carcinoma, and acute liver failure. The treatment of diabetes mellitus (DM) in cirrhotic patients has particular challenges as follows: (1) about half the patients have malnutrition; (2) patients already have advanced liver disease when clinical DM is diagnosed; (3) most of the oral antidiabetic agents (ADAs) are metabolized in the liver; (4) patients often have episodes of hypoglycemia. The aim of this consensus group convened during the National Insulin Summit 2015, Puducherry, was to focus on the challenges with glycemic management, with particular emphasis to safety of ADAs across stages of liver dysfunction. Published literature, product labels, and major clinical guidelines were reviewed and summarized. The drug classes included are biguanides (metformin), the second- or third-generation sulfonylureas, alpha-glucosidase inhibitors, thiazolidinediones, dipeptidyl peptidase-4 inhibitors, sodium-glucose co-transporter 2 inhibitors, glucagon-like peptide-1 receptor agonists, and currently available insulins. Consensus recommendations have been drafted for glycemic targets and dose modifications of all ADAs. These can aid clinicians in managing patients with diabetes and liver disease.

Role of nonalcoholic fatty liver disease as risk factor for drug-induced hepatotoxicity

BACKGROUND

Obesity is often associated with nonalcoholic fatty liver disease (NAFLD), which refers to a large spectrum of hepatic lesions including fatty liver, nonalcoholic steatohepatitis (NASH) and cirrhosis. Different investigations showed or suggested that obesity and NAFLD are able to increase the risk of hepatotoxicity of different drugs. Some of these drugs could induce more frequently an acute hepatitis in obese individuals whereas others could worsen pre-existing NAFLD.

AIM

The main objective of the present review was to collect the available information regarding the role of NAFLD as risk factor for drug-induced hepatotoxicity. For this purpose, we performed a data-mining analysis using different queries including drug-induced liver injury (or DILI), drug-induced hepatotoxicity, fatty liver, nonalcoholic fatty liver disease (or NAFLD), steatosis and obesity. The main data from the collected articles are reported in this review and when available, some pathophysiological hypotheses are put forward.

RELEVANCE FOR PATIENTS

Drugs that could pose a potential risk in obese patients include compounds belonging to different pharmacological classes such as acetaminophen, halothane, methotrexate, rosiglitazone, stavudine and tamoxifen. For some of these drugs, experimental investigations in obese rodents confirmed the clinical observations and unveiled different pathophysiological mechanisms which could explain why these pharmaceuticals are particularly hepatotoxic in obesity and NAFLD. Other drugs such as pentoxifylline, phenobarbital and omeprazole might also pose a risk but more investigations are required to determine whether this risk is significant or not. Because obese people often take several drugs for the treatment of different obesity-related diseases such as type 2 diabetes, hyperlipidemia and coronary heart disease, it is urgent to identify the main pharmaceuticals that can cause acute hepatitis on a fatty liver background or induce NAFLD worsening.

Inhibition of JNK suppresses autophagy and attenuates insulin resistance in a rat model of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease, the pathological process of which is complex. Activation of the c‑Jun N‑terminal kinase (JNK) signaling pathway is associated with the mechanism underlying obesity-induced insulin resistance. Furthermore, the JNK signaling pathway and dysfunctional autophagy serve important roles in hepatic lipid metabolism. However, the exact role of JNK in autophagy and obesity‑induced insulin resistance is not fully understood. Therefore, the present study aimed to investigate the underlying mechanisms by which the JNK signaling pathway regulates autophagy and insulin resistance in fatty liver. A rat model of NAFLD was established using a high‑fat diet (HFD), and insulin resistance in the livers of HFD rats was determined by peritoneal glucose tolerance testing. The results indicated that a HFD induced impaired glucose tolerance, liver function injury, insulin resistance and increased autophagy in rats. Treatment with SP600125, an inhibitor of JNK, relieved NAFLD in rats. Furthermore, SP600125 decreased the expression levels of autophagy-associated genes, including Beclin-1, microtubule-associated protein 1A/1B light chain 3, autophagy related gene (Atg)3 and Atg5, and the phosphorylation of insulin receptor (IR) β-subunit, IR substrate-1 and protein kinase B in vivo. In conclusion, JNK inhibition may suppress autophagy and attenuate insulin resistance. Therefore, JNK inhibition may provide a novel therapeutic strategy for the treatment of NAFLD.

Nuclear Receptors as Therapeutic Targets in Liver Disease: Are We There Yet?

Nuclear receptors (NR) are ligand-modulated transcription factors that play diverse roles in cell differentiation, development, proliferation, and metabolism and are associated with numerous liver pathologies such as cancer, steatosis, inflammation, fibrosis, cholestasis, and xenobiotic/drug-induced liver injury. The network of target proteins associated with NRs is extremely complex, comprising coregulators, small noncoding microRNAs, and long noncoding RNAs. The importance of NRs as targets of liver disease is exemplified by the number of NR ligands that are currently used in the clinics or in clinical trials with promising results. Understanding the regulation by NR during pathophysiological conditions, and identifying ligands for orphan NR, points to a potential therapeutic approach for patients with liver diseases. An overview of complex NR metabolic networks and their pharmacological implications in liver disease is presented here.

The effects of onion consumption on treatment of metabolic, histologic, and inflammatory features of nonalcoholic fatty liver disease

Background

The aim of this study was to evaluate the effects of onion powder consumption on treatment of Non-alcoholic Fatty Liver Disease (NAFLD) in an experimental model of disease.

Methods

Sprague–Dawley rats were fed high-fat (HF) diet for seven weeks to induce the NAFLD. Then, they were treated by either the same diet (HF), or high-fat diet plus 7 % onion powder (HF + onion), or chow diet (control), or chow diet plus 7 % onion powder (control + onion)ad libitum for four weeks. Serum levels of fasting glucose, triglyceride, cholesterol, liver enzymes, insulin, and hepatic tumor necrosis factor-alpha (TNF-α) gene expression were determined. Hepatic histology was examined by Hematoxylin and Eosin stain.

Results

Dietary food intakes and weigh gain were significantly more in animals fed control + onion diet in comparison to the other groups. Animals fed control or control + onion diet had significantly lower plasma levels of hepatic enzymes, lipid profile, glycemic indices, and hepatic TNF-α gene expression as compared with HF diet fed groups; however, there was no significant difference in the histopathologic features of NAFLD among different groups.

Conclusion

Our results indicate that onion consumption can be effective in NAFLD management when it is combined with a healthy diet.

Electronic supplementary material

The online version of this article (doi:10.1186/s40200-016-0248-4) contains supplementary material, which is available to authorized users.

The Relationship between Type 2 Diabetes Mellitus and Non-Alcoholic Fatty Liver Disease Measured by Controlled Attenuation Parameter

PURPOSE

The severity of non-alcoholic fatty liver disease (NAFLD) in type 2 diabetes mellitus (T2DM) population compared with that in normal glucose tolerance (NGT) individuals has not yet been quantitatively assessed. We investigated the prevalence and the severity of NAFLD in a T2DM population using controlled attenuation parameter (CAP).

MATERIALS AND METHODS

Subjects who underwent testing for biomarkers related to T2DM and CAP using Fibroscan® during a regular health check-up were enrolled. CAP values of 250 dB/m and 300 dB/m were selected as the cutoffs for the presence of NAFLD and for moderate to severe NAFLD, respectively. Biomarkers related to T2DM included fasting glucose/insulin, fasting C-peptide, hemoglobin A1c (HbA1c), glycoalbumin, and homeostasis model assessment of insulin resistance of insulin resistance (HOMA-IR).

RESULTS

Among 340 study participants (T2DM, n=66; pre-diabetes, n=202; NGT, n=72), the proportion of subjects with NAFLD increased according to the glucose tolerance status (31.9% in NGT; 47.0% in pre-diabetes; 57.6% in T2DM). The median CAP value was significantly higher in subjects with T2DM (265 dB/m) than in those with pre-diabetes (245 dB/m) or NGT (231 dB/m) (all p<0.05). Logistic regression analysis showed that subjects with moderate to severe NAFLD had a 2.8-fold (odds ratio) higher risk of having T2DM than those without NAFLD (p=0.02; 95% confidence interval, 1.21-6.64), and positive correlations between the CAP value and HOMA-IR (ρ0.407) or fasting C-peptide (ρ0.402) were demonstrated.

CONCLUSION

Subjects with T2DM had a higher prevalence of severe NAFLD than those with NGT. Increased hepatic steatosis was significantly associated with the presence of T2DM, and insulin resistance induced by hepatic fat may be an important mechanistic connection.

Effects of the new thiazolidine derivative LPSF/GQ-02 on hepatic lipid metabolism pathways in non-alcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is considered the most common manifestation of metabolic syndrome. One of its most important features is the accumulation of triglycerides in the hepatocyte cells. Thiazolidinediones (TZDs) act as insulin sensitizers and are used to treat patients with type 2 diabetes and other conditions that are resistant to insulin, such as hepatic steatosis. Controversially, TZDs are also associated with the development of cardiovascular events and liver problems. For this reason, new therapeutic strategies are necessary to improve liver function in patients with chronic liver diseases. The aim of the present study was to evaluate the effects of LPSF/GQ-02 on the liver lipid metabolism in a murine model of NAFLD. Eighty male LDLR-/- mice were divided into 3 groups: 1-fed with a high-fat diet (HFD); 2-HFD+Pioglitazone (20mg/kg/day); 3-HFD+LPSF/GQ-02 (30mg/kg/day). The experiments lasted 12 weeks and drugs were administered daily by gavage in the final four weeks. The liver was processed for optical microscopy, Oil Red O, immunohistochemistry, immunofluorescence and western blot analysis. LPSF/GQ-02 effectively decreased fat accumulation, increased the hepatic levels of p-AMPK, FoxO1, ATGL, p-ACC and PPARα, and reduced the expression of LXRα, SREBP-1c and ACC. These results suggest that LPSF/GQ-02 acts directly on the hepatic lipid metabolism through the activation of the PPAR-α/AMPK/FoxO1/ATGL lipolytic pathway, and the inhibition of the AMPK/LXR/SREBP-1c/ACC/FAS lipogenic pathway.

Insulin resistance in development and progression of nonalcoholic fatty liver disease

Although insulin resistance (IR) is strongly associated with nonalcoholic fatty liver disease (NAFLD), the association of IR and NAFLD is not universal and correlation between IR and severity of NAFLD is still controversial. In this review, we summarize recent evidence that partially dissociates insulin resistance from NAFLD. It has also been reported that single-nucleotide polymorphisms in the diacylglycerol acyltransferase gene, rather than IR, account for the variability in liver fat content. Polymorphisms of the patatin-like phospholipase 3 gene have also been reported to be associated with NAFLD without metabolic syndrome, which suggests that genetic conditions that promote the development of fatty changes in the liver may occur independently of IR. Moreover, environmental factors such as nutrition and physical activity as well as small intestinal bacterial overgrowth have been linked to the pathogenesis of NAFLD, although some of the data are conflicting. Therefore, findings from both genetically engineered animal models and humans with genetic conditions, as well as recent studies that have explored the role of environmental factors, have confirmed the view that NAFLD is a polygenic disease process caused by both genetic and environmental factors. Therefore, IR is not the sole predictor of the pathogenesis of NAFLD.

Computerized tomography measured liver fat is associated with low levels of N-terminal pro-brain natriuretic protein (NT-proBNP). Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND AIMS

N-terminal pro B-type natriuretic peptide (NT-proBNP) is inversely associated with diabetes mellitus, obesity and metabolic syndrome. We aim to characterize the association between NT-proBNP and nonalcoholic fatty liver disease (NAFLD), a condition strongly associated with metabolic syndrome.

METHODS

4529 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) free of cardiovascular disease, without self-reported liver disease and not diabetic at their baseline visit in 2000-2002 were included in this analysis. NAFLD was defined by a liver attenuation <40 HU. Relative prevalence (RP) for NAFLD was assessed adjusted for age, race, and sex, percentage of dietary calories derived from fat, total intentional exercise, alcoholic drinks per week, and interleukin-6 by quintiles of NT-proBNP. Adjusted linear spline model was used to characterize a non-linear association between NT-proBNP and liver fat. The inflection point (IP) was the NT-proBNP concentration where there was a change in slope in the association between liver attenuation and NT-proBNP.

RESULTS

RP for NAFLD decreased by 30% from the lowest to the highest quintile of NT-proBNP, p=0.01. We observed an inverse linear association between NT-proBNP and liver fat, which plateaued (IP) at an NT-proBNP concentration of 45pg/mL. Linear regression coefficient (SE) per unit of NT-proBNP less than and greater than or equal to IP was of 0.05 (0.02), p=0.001 and 0.0006 (0.0008), p=0.5, respectively; differences between slopes, p<0.0001.

CONCLUSIONS

In this cross-sectional study of a community based multiethnic sample of non-diabetic adults, low levels of NT-proBNP are associated with greater prevalence of NAFLD.

Dietary walnut reduces hepatic triglyceride content in high-fat-fed mice via modulation of hepatic fatty acid metabolism and adipose tissue inflammation

In this study, we evaluated the protective effects of dietary walnuts on high-fat diet (HFD)-induced fatty liver and studied the underlying mechanisms. Male C57BL/6J mice were fed either a regular rodent chow or HFD (45% energy-derived) with or without walnuts (21.5% energy-derived) for 20weeks. Walnut supplementation did not change HFD-induced increase in body weight or visceral fat mass. However, dietary walnuts significantly decreased the amounts of hepatic triglyceride (TG) observed in HFD-fed mice. The addition of walnuts significantly altered the levels of proteins, involved in the hepatic lipid homeostasis, including AMP-activated protein kinase, fatty acid synthase and peroxisome proliferator-activated receptor-α. Since adipocyte inflammation and apoptosis are reportedly important in regulating hepatic fat accumulation, we also evaluated the protective effects of walnuts on adipose tissue injury. Real-time polymerase chain reaction results revealed that adipose tissues isolated from mice fed the HFD+walnut diets showed significantly decreased levels of macrophage infiltration with suppressed expression of proinflammatory genes compared to those significantly elevated in mice fed HFD alone. These improvements also coincided with reduction of HFD-induced apoptosis of adipocytes by dietary walnuts. However, the supplemented walnuts did not significantly alter HFD-induced peripheral glucose intolerance or insulin resistance despite a trend of improvement. Collectively, these results demonstrate that the protective effects of walnuts against HFD-induced hepatic TG accumulation in mice are mediated, at least partially, by modulating the key proteins in hepatic lipid homeostasis and suppression of the genes related to adipose tissue inflammation and macrophage infiltration as well as prevention of adipocyte apoptosis.

A concise review of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome and the incidence of which is rising rapidly due to the increasing epidemic of obesity in both adults and children. The initial accumulation of fat followed by subsequent inflammation is central to the development of liver damage, and is critically influenced by host factors including age, gender, presence of diabetes, genetic polymorphisms and more recently by the gut microbiome. An increasing body of data suggest that NAFLD is also an independent risk factor of cardiovascular disease, which remains the commonest cause of mortality in such patients. This review focusses on the pathogenesis of NAFLD, and the evolution of new approaches to the management and treatment of NAFLD.

Glucagon-like peptide-1 suppresses palmitic acid induced L02 cell apoptosis through JNK pathway

AIM: To investigate the potential effects of glucagon-like peptide-1 (GLP-1) on palmitic acid (PA) induced apoptosis of hepatic L02 cells and the underlying mechanism.

METHODS: L02 cells were stimulated with different levels (0.125, 0.250 and 0.500 mmol/L) of PA for different durations (12, 24 and 48 h) in the presence or absence of GLP-1. Cell Counting Kit-8 (CCK-8) assay was used to analyze the inhibitory effects on growth of L02 cells, and terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) assay was used to observe the apoptotic rate of the cells. The expression of c-Jun N-terminal kinase (JNK), c-Jun, p-JNK and p-c-Jun proteins was detected by Western blot assay.

RESULTS: The growth of the L02 cells was significantly inhibited by PA in vitro, and PA induced the expression of p-JNK and p-c-Jun. GLP-1 suppressed the activation of JNK and c-Jun induced by PA.

CONCLUSION: PA can inhibit the proliferation of L02 cells and induce cell apoptosis. The JNK signaling pathway is probably involved in the mechanism of PA induced apoptosis.

Phosphorylation of sterol regulatory element-binding protein (SREBP)-1c by p38 kinases, ERK and JNK influences lipid metabolism and the secretome of human liver cell line HepG2

The transcription factor sterol regulatory element binding protein (SREBP)-1c plays a pivotal role in lipid metabolism. In this report we identified the main phosphorylation sites of MAPK-families, i.e. p38 stress-activated MAPK (p38), ERK-MAPK (ERK) or c-JUN N-terminal protein kinases (JNK) in SREBP-1c. The major phosphorylation sites of p38, i.e. serine 39 and threonine 402, are identical to those we recently identified in the splice-variant SREBP-1a. In contrast, ERK and JNK phosphorylate SREBP-1c at two major sites, i.e. threonine 81 and serine 93, instead of one site in SREBP-1a. Functional analyses of the biological outcome in the human liver cell line HepG2 reveals SREBP-1c phosphorylation dependent alteration in lipid metabolism and secretion pattern of lipid transporting proteins, e.g. ApoE or ApoA1. These results suggest that phosphorylation of SREBP-1c by different MAPKs interferes with lipid metabolism and the secretory activity of liver cells.

Effect of Vitamin E and Metformin on Fatty Liver Disease in Obese Children- Randomized Clinical Trial

BACKGROUND

We evaluated the effect of vitamin E and metformin on fatty liver disease in obese children.

METHODS

This interventional study has been done on 119 children with Non-alcoholic fatty liver disease (based on sonography results). Patients were divided into four treatment groups; they received metformin 1gr daily (age< 12 years), metformin 1.5 gr daily (age> 12 years), vitamin E 800 U daily and vitamin E 400 U daily. Liver sonography was performed for patients for two periods of two months. This trial was registered in Iranian Registry of Clinical Trials (IRCT), No.IRCT2013021012421N1.

RESULTS

The study group comprised 119 individuals (62 females, 57 males). The mean age was 10± 3.19 yr. There was no significant difference in terms of sex and BMI between the groups. Overall liver sonography showed normal liver in 66 patients (55.46%), 66.63% after two months and 33.37% after four months. After two months, the most therapeutic response observed in the group which received vitamin E 800 u daily (48.1%) and the least therapeutic response was in the group which received vitamin E 400 u daily (14.3%). After four months, the greater response was seen in vitamin E 400 u daily group (45.8%) and the least response in the metformin 1 gram daily group (19%).

CONCLUSION

In comparison with metformin, vitamin E is more influential in remission; however both are efficient in treatment of fatty liver. Vitamin E 400 u daily responses better in four-month treatment.

Regulatory effect of hydrogen sulfide on β oxidation in fatty liver in rats

AIM: To observe the regulatory effect of hydrogen sulfide on β oxidation in fatty liver in rats.

METHODS: Eighteen male SD rats were randomly divided into a normal control group, a high-fat diet group and a high-fat diet + NaHS group. High-fat diet was ordinary diet supplemented with 2% cholesterol and 18% lard. The high-fat diet + NaHS group was given a high-fat diet and intraperitoneal injection of 400 mmol/L sodium hydrosulfide solution (5 mL/kg). Eight weeks after treatment, the animals were killed. The content of ketones and enoyl-CoA hydratase activity in liver homogenates were measured, and pathological changes in the liver were observed.

RESULTS: After 8 wk of treatment, fatty liver was successfully induced. Application of sodium hydrosulfide reduced fatty liver significantly. Intrahepatic triglyceride and cholesterol significantly increased in the high-fat diet group compared with the normal control group (3.87 mmol/L ± 2.63 mmol/L vs 1.18 mmol/L ± 0.85 mmol/L, 5.00 mmol/L ± 1.01 mmol/L vs 2.61 mmol/L ± 0.33 mmol/L), while treatment with sodium hydrosulfide significantly reduced hepatic lipid composition (2.28 mmol/L ± 0.51 mmol/L vs 3.87 ± 2.63 mmol/L, 4.50 mmol/L ± 1.25 mmol/L vs 5.00 mmol/L ± 1.01 mmol/L). Compared with the normal control group, hydrogen sulfide content in the high-fat diet group was significantly reduced (14.00 µmol/L ± 6.21 µmol/L vs 20.20 µmol/L ± 11.90 µmol/L); however, application of sodium hydrosulfide significantly increased hydrogen sulfide content (48.20 µmol/L ± 8.50 µmol/L vs 14.00 µmol/L ± 6.21 µmol/L). Compared with the control animals, the liver enoyl-CoA activity was significantly reduced in the high-fat diet group (25.0 µmol/min ± 7.7 µmol/min vs 12.6 µmol/min ± 3.1 µmol/min), by up to 50%, while sodium hydrosulfide significantly increased enoyl-CoA activity (19.9 µmol/min ± 6.0 µmol/min vs 12.6 µmol/min ± 3.1 µmol/min), by 60%. Hydrogen sulfide content was negatively correlated with TG and TC in the high-fat diet group (r = -0.621, -0.432, P = 0.01036, 0.04497), but positively correlated with enoyl-CoA hydratase activity (r = 0.513, P = 0.00833).

CONCLUSION: Hydrogen sulfide promotes β oxidation and reduces fat accumulation in fatty liver in rats.