scholarly journals Identification and functional characterisation of a rare MTTP variant underlying hereditary non-alcoholic fatty liver disease.

2021 ◽  
Author(s):  
Jane I. Grove ◽  
Peggy Cho Kiu Lo ◽  
Nick Shrine ◽  
Julian Barwell ◽  
Louise V. Wain ◽  
...  
Keyword(s):  
Liver Disease ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
Causal Variant ◽  
Wild Type ◽  
Alcoholic Fatty Liver ◽  
Triglyceride Accumulation ◽  
Donor Skin ◽  
Alcoholic Fatty Liver Disease ◽  
Rare Causal Variant

Background and aims: Non-alcoholic fatty liver disease (NAFLD) is a complex trait that has a global prevalence estimated as 25%. We aimed to identify the genetic variant underlying a four-generation family with progressive NAFLD leading to cirrhosis, decompensation and development of hepatocellular carcinoma in the absence of common risk factors such as obesity and type 2 diabetes. Methods: Exome sequencing and genome comparisons were used to identify the likely causal variant. We extensively characterised the clinical phenotype and post-prandial metabolic responses of family members with the identified novel variant in comparison to healthy non-carriers and wild type patients with NAFLD. Variant-expressing hepatocyte-like cells (HLCs) were derived from human induced pluripotent stem cells generated from homozygous donor skin fibroblasts. The phenotype was assessed using imaging, targeted RNA analysis and molecular expression arrays. Results: We identified a rare causal variant in MTTP, c.1691T>C p.I564T (rs745447480) encoding microsomal triglyceride transfer protein (MTP) associated with progressive non-alcoholic fatty liver disease, unrelated to metabolic syndrome. Although other described mutations in MTTP cause abetalipoproteinemia, neither homozygotes nor heterozygotes exhibited characteristic manifestations of this severe disease. HLCs derived from a homozygote donor had lower lipoprotein ApoB secretion, compared to wild type cells. Cytoplasmic triglyceride accumulation in HLCs triggered endoplasmic reticulum stress, secretion of pro-inflammatory mediators and production of reactive oxygen species. Conclusion: We have identified and characterized a rare causal variant in MTTP and homozygosity for MTTP p.I564T is associated with progressive NAFLD without any other manifestations of abetalipoproteinemia.

scholarly journals SREBP-2/PNPLA8 axis improves non-alcoholic fatty liver disease through activation of autophagy

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Kwang-Youn Kim ◽  
Hyun-Jun Jang ◽  
Yong Ryoul Yang ◽  
Kwang-Il Park ◽  
JeongKon Seo ◽  
...  
Keyword(s):  
Liver Disease ◽  
Fatty Liver ◽  
High Fat Diet ◽  
Fatty Liver Disease ◽  
Hepatic Triglyceride ◽  
Alcoholic Fatty Liver ◽  
Over Expression ◽  
Beneficial Effects ◽  
Triglyceride Accumulation ◽  
Alcoholic Fatty Liver Disease

Abstract Dysregulated autophagy is associated with steatosis and non-alcoholic fatty liver disease (NAFLD), however the mechanisms connecting them remain poorly understand. Here, we show that co-administration of lovastatin and ezetimibe (L/E) significantly reverses hepatic triglyceride accumulation concomitant with an increase in SREBP-2 driven autophagy in mice fed a high-fat diet (HFD). We further show that the statin mediated increase in SREBP-2 directly activates expression of patatin-like phospholipase domain-containing enzyme 8 (PNPLA8) gene, and PNPLA8 associates with autophagosomes and is associated with a decrease in cellular triglyceride. Moreover, we show that over-expression of PNPLA8 dramatically decreases hepatic steatosis through increased autophagy in hepatocytes of HFD-fed mice. Live-cell imaging analyses also reveal that PNPLA8 dynamically interacts with LC3 and we suggest that the SREBP-2/PNPLA8 axis represents a novel regulatory mechanism for lipid homeostasis. These data provide a possible mechanism for the reported beneficial effects of statins for decreasing hepatic triglyceride levels in NAFLD patients.

scholarly journals Molecular pathways involved in the improvement of non-alcoholic fatty liver disease

2013 ◽  
Vol 51 (1) ◽  
pp. 167-179 ◽  
Author(s):  
Gilberto Paz-Filho ◽  
Claudio Alberto Mastronardi ◽  
Brian J Parker ◽  
Ainy Khan ◽  
Antonio Inserra ◽  
...  
Keyword(s):  
Body Weight ◽  
Liver Disease ◽  
Liver Injury ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
Glutathione Metabolism ◽  
Wild Type ◽  
Alcoholic Fatty Liver ◽  
The Metabolic Syndrome ◽  
Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis are components of the metabolic syndrome. Serum leptin levels are elevated in obesity, but the role of leptin in the pathophysiology of the liver involvement is still unclear. To identify the effects and mechanisms by which leptin influences the pathogenesis of NAFLD, we performed epididymal white adipose tissue (eWAT) transplantation from congenic wild-type mice into the subcutaneous dorsal area ofLepob/obrecipient mice and compared the results with those of theLepob/obsham-operated mice. The mice were followed for 102–216 days. During killing, the transplanted mice had significantly lost body weight and exhibited significantly higher leptin levels, improved glucose tolerance, and lower liver injury scores than the sham-operated mice. Liver microarray analysis showed that novel pathways related to GA-binding protein (GABP) transcription factor targets, pheromone binding, and olfactory signaling were differentially expressed in the transplanted mice. Our data also replicate pathways known to be involved in NAFLD, such as those involved in the regulation of microRNAs, lipid, glucose, and glutathione metabolism, peroxisome proliferator-activated receptor signaling, cellular regulation, carboxylic acid processes, iron, heme, and tetrapyrrole binding, immunity and inflammation, insulin signaling, cytochrome P450 function, and cancer. Conclusion: wild-type eWAT transplantation intoLepob/obmice led to improvements in metabolism, body weight, and liver injury, possibly attributed to the production of leptin by the transplanted eWAT. These improvements were accompanied by the differential expression of novel pathways. The causal relationship between GABP downregulation and NAFLD improvement remains to be determined.

scholarly journals PNPLA3, TM6SF2, and MBOAT7 Influence on Nutraceutical Therapy Response for Non-alcoholic Fatty Liver Disease: A Randomized Controlled Trial

2021 ◽  
Vol 8 ◽  
Author(s):  
Marcello Dallio ◽  
Mario Masarone ◽  
Mario Romeo ◽  
Concetta Tuccillo ◽  
Filomena Morisco ◽  
...  
Keyword(s):  
Liver Disease ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
Controlled Trial ◽  
Daily Intake ◽  
Therapeutic Regimen ◽  
Thiobarbituric Acid Reactive Substance ◽  
Wild Type ◽  
Alcoholic Fatty Liver ◽  
Alcoholic Fatty Liver Disease

Introduction: PNPLA3, TM6SF2, and MBOAT7 genes play a crucial role in non-alcoholic fatty liver disease (NAFLD) development and worsening. However, few data are available on their treatment response influence. The aim of this trial is to explore the effect derived from silybin-phospholipids complex (303 mg of silybin-phospholipids complex, 10 μg of vitamin D, and 15 mg of vitamin E twice a day for 6 months) oral administration in NAFLD patients carrying PNPLA3-rs738409, TM6SF2-rs58542926, or MBOAT7-rs641738 genetic variants.Materials and Methods: In all, 92 biopsy-proven NAFLD patients were grouped in 30 NAFLD wild type controls, 30 wild type treated patients, and 32 mutated treated ones. We assessed glycemia (FPG), insulinemia, HOMA-IR, aspartate and alanine aminotransferases (AST, ALT), C-reactive protein (CRP), thiobarbituric acid reactive substance (TBARS), stiffness, controlled attenuation parameter (CAP), dietary daily intake, and physical activity at baseline and end of treatment.Results: The wild-type treated group showed a significant improvement of FPG, insulinemia, HOMA-IR, ALT, CRP, and TBARS (p < 0.05), whereas no improvements were recorded in the other two study groups. NAFLD wild type treated patients showed higher possibilities of useful therapeutic outcome (p < 0.01), obtained from the prescribed therapeutic regimen, independently from age, sex, comorbidities, medications, CAP, and stiffness in comparison to the mutated group.Discussion: The assessed mutations are independently associated with no response to a silybin-based therapeutic regimen and could be considered as useful predictive markers in this context.Clinical Trial Registry Number:www.ClinicalTrials.gov, identifier: NCT04640324.

scholarly journals The Role of Lipophagy in the Development and Treatment of Non-Alcoholic Fatty Liver Disease

2021 ◽  
Vol 11 ◽  
Author(s):  
Aldo Grefhorst ◽  
Ivo P. van de Peppel ◽  
Lars E. Larsen ◽  
Johan W. Jonker ◽  
Adriaan G. Holleboom
Keyword(s):  
Fatty Acid ◽  
Liver Disease ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
Lipid Homeostasis ◽  
Alcoholic Fatty Liver ◽  
Hepatic Lipid ◽  
Triglyceride Accumulation ◽  
Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) or metabolic (dysfunction) associated liver disease (MAFLD), is, with a global prevalence of 25%, the most common liver disorder worldwide. NAFLD comprises a spectrum of liver disorders ranging from simple steatosis to steatohepatitis, fibrosis, cirrhosis and eventually end-stage liver disease. The cause of NAFLD is multifactorial with genetic susceptibility and an unhealthy lifestyle playing a crucial role in its development. Disrupted hepatic lipid homeostasis resulting in hepatic triglyceride accumulation is an hallmark of NAFLD. This disruption is commonly described based on four pathways concerning 1) increased fatty acid influx, 2) increased de novo lipogenesis, 3) reduced triglyceride secretion, and 4) reduced fatty acid oxidation. More recently, lipophagy has also emerged as pathway affecting NAFLD development and progression. Lipophagy is a form of autophagy (i.e. controlled autolysosomal degradation and recycling of cellular components), that controls the breakdown of lipid droplets in the liver. Here we address the role of hepatic lipid homeostasis in NAFLD and specifically review the current literature on lipophagy, describing its underlying mechanism, its role in pathophysiology and its potential as a therapeutic target.

Vitamin D levels are not associated with non-alcoholic fatty liver disease severity in a Brazilian population

2020 ◽  
pp. 1-8
Author(s):  
Jeniffer Danielle M. Dutra ◽  
Quelson Coelho Lisboa ◽  
Silvia Marinho Ferolla ◽  
Carolina Martinelli M. L. Carvalho ◽  
Camila Costa M. Mendes ◽  
...  
Keyword(s):  
Vitamin D ◽  
Liver Disease ◽  
Fatty Liver ◽  
Disease Severity ◽  
Fatty Liver Disease ◽  
Hypovitaminosis D ◽  
Alcoholic Fatty Liver ◽  
Vitamin D Levels ◽  
The Mean ◽  
Alcoholic Fatty Liver Disease

Abstract. Some epidemiological evidence suggests an inverse correlation between non-alcoholic fatty liver disease (NAFLD) frequency and vitamin D levels. Likewise, a beneficial effect of vitamin D on diabetes mellitus (DM) and insulin resistance has been observed, but this is an unsolved issue. Thus, we aimed to investigate the prevalence of hypovitaminosis D in a NAFLD Brazilian population and its association with disease severity and presence of comorbidities. In a cross-sectional study, the clinical, biochemical and histological parameters of 139 NAFLD patients were evaluated according to two different cut-off points of serum 25-hydroxyvitamin D levels (20 ng/mL and 30 ng/mL). The mean age of the population was 56 ± 16 years, most patients were female (83%), 72% had hypertension, 88% dyslipidemia, 46% DM, 98% central obesity, and 82% metabolic syndrome. Serum vitamin D levels were < 30 ng/mL in 78% of the patients, and < 20 ng/mL in 35%. The mean vitamin D level was 24.3 ± 6.8 ng/mL. The comparison between the clinical, biochemical and histological characteristics of the patients according to the levels of vitamin D showed no significant difference. Most patients with NAFLD had hypovitaminosis D, but low vitamin D levels were not related to disease severity and the presence of comorbidities.

Non-Alcoholic Fatty Liver Disease in Overweight Children and its Relationship with Retinol Serum Levels

2008 ◽  
Vol 78 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Suano de Souza ◽  
Silverio Amancio ◽  
Saccardo Sarni ◽  
Sacchi Pitta ◽  
Fernandes ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Liver Disease ◽  
Fatty Liver ◽  
Lipid Profile ◽  
Fatty Liver Disease ◽  
Thiobarbituric Acid ◽  
Serum Levels ◽  
Control Group ◽  
Alcoholic Fatty Liver ◽  
Alcoholic Fatty Liver Disease

Objectives: To evaluate the frequency of non-alcoholic fatty liver disease, the retinol serum levels, lipid profile, and insulin resistance in overweight/obese children. To relate these biochemical variables with the risk of this disease in the population studied. Methods: The study was cross-sectional and prospective, with 46 overweight/obese school children (28 female, 18 male; mean age 8.6 years). The control group consisted of 45 children, paired by age and gender. Hepatic steatosis, evaluated by ultrasound, was classified as normal, mild, moderate, or severe. Also evaluated were serum retinol levels; thiobarbituric acid reactive substances; lipid profile; and fasting glucose and serum insulin levels, used for the calculation of the Homeostasis Model Assessment. Results: Hepatic ultrasound alterations were found in 56.5% and 48,9% of the overweight/obese and control group children, respectively. Presence of obesity was associated with high levels of triglycerides (OR = 4.6; P = 0.002). In the studied children, the risk of steatosis was related to a trend to a higher percentage of retinol inadequacy (OR = 2.8; p = 0.051); there was no association with thiobarbituric acid reactive substances, lipid profile, or insulin resistance. Conclusions: The high frequency of non-alcoholic fatty liver disease in both groups, evaluated by hepatic ultrasound, in low-socioeconomic level children, independent of nutritional condition and without significant association with insulin resistance, emphasizes that especially in developing countries, other risk factors such as micronutrient deficiencies (e.g. vitamin A) are involved.

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