PNPLA3 as a Genetic Determinant of Risk for and Severity of Non-alcoholic Fatty Liver Disease Spectrum

Genetic predisposition of metabolic dysfunction-associated steatotic liver disease: a population-based genome-wide association study

BACKGROUND/PURPOSE

Although metabolic dysfunction-associated steatotic liver disease (MASLD) has been proposed to replace the diagnosis of non-alcoholic fatty liver disease (NAFLD) with new diagnostic criteria since 2023, the genetic predisposition of MASLD remains to be explored.

METHODS

Participants with data of genome-wide association studies (GWAS) in the Taiwan Biobank database were collected. Patients with missing data, positive for HBsAg, anti-HCV, and alcohol drinking history were excluded. MASLD was defined if having hepatic steatosis on ultrasound, plus at least one of cardiometabolic criteria. The Taiwan biobank used two genetic chips during the period of data collection: Taiwan biobank version 1 (TWBv1) as the initial chip and TWBv2 specifically designed for the Taiwanese population. TWBv2 was used as test group and TWBv1 as validation group. NAFLD fibrosis score (NFS) was used to assess the degree of liver fibrosis, and carotid plaques on duplex ultrasound were employed for the diagnosis of atherosclerosis.

RESULTS

In a total of 16,407 (mean age 55.35 ± 10.41; 29.6% males) participants, 6722 (41.0%) had MASLD. Eleven single-nucleotide polymorphisms (SNP) were identified to be associated with MASLD. Their functions were exonic in two and intronic in nine. They were related to the PNALA3, and SAMM50 genes located on chromosome 22. The linkage disequilibrium showed a high correlation with each other. Four SNPs of PNALA3 and SAMM50 genes had increased risk of MASLD and higher levels of AST/ALT. In addition, there was no association of these two genes with glucose metabolism, but better lipid profiles in SAMM50.

CONCLUSIONS

This large GWAS study indicates that eleven SNPs of PNPLA3 and SAMM50 genes predispose the development of MASLD in Taiwanese population.

Genetic Risk Factors for Metabolic Dysfunction-Associated Steatotic Liver Disease

Metabolic dysfunction-associated steatotic liver disease (MASLD), is the most common cause of liver disease, and its burden on health systems worldwide continues to rise at an alarming rate. MASLD is a complex disease in which the interactions between susceptible genes and the environment influence the disease phenotype and severity. Advances in human genetics over the past few decades have provided new opportunities to improve our understanding of the multiple pathways involved in the pathogenesis of MASLD. Notably, the PNPLA3, TM6SF2, GCKR, MBOAT7 and HSD17B13 single nucleotide polymorphisms have been demonstrated to be robustly associated with MASLD development and disease progression. These genetic variants play crucial roles in lipid droplet remodeling, secretion of hepatic very low-density lipoprotein and lipogenesis, and understanding the biology has brought new insights to this field. This review discusses the current body of knowledge regarding these genetic drivers and how they can lead to development of MASLD, the complex interplay with metabolic factors such as obesity, and how this information has translated clinically into the development of risk prediction models and possible treatment targets.

Liver fat as risk factor of hepatic and cardiometabolic diseases

Non-alcoholic fatty liver disease (NAFLD) is a disorder characterized by excessive accumulation of fat in the liver that can progress to liver inflammation (non-alcoholic steatohepatitis [NASH]), liver fibrosis, and cirrhosis. Although most efforts for drug development are focusing on the treatment of the latest stages of NAFLD, where significant fibrosis and NASH are present, findings from studies suggest that the amount of liver fat may be an important independent risk factor and/or predictor of development and progression of NAFLD and metabolic diseases. In this review, we first describe the current tools available for quantification of liver fat in humans and then present the clinical and pathophysiological evidence that link liver fat with NAFLD progression as well as with cardiometabolic diseases. Finally, we discuss current pharmacological and non-pharmacological approaches to reduce liver fat and present open questions that have to be addressed in future studies.

Non-alcoholic Steatohepatitis in Asians: Current Perspectives and Future Directions

Non-alcoholic steatohepatitis (NASH) is a subset of non-alcoholic fatty liver disease (NAFLD), which, apart from excess fat in the liver, may be characterised by some level of inflammatory infiltration and fibrogenesis, occasionally progressing to liver cirrhosis or hepatocellular carcinoma (HCC). The objective of the current review is to elucidate the rising prevalence, the role of microbiome and genetics in pathogenesis, diagnostic challenges, and novel treatment alternatives for NASH. Newer diagnostic techniques are being developed since using liver biopsy in a larger population is not a reasonable option and is primarily restricted to clinical research, at least in developing countries. Besides these technical challenges, another important factor leading to deviation from guideline practice is the lack of health insurance coverage in countries like India. It leads to reluctance on the part of physicians and patients to delay required tests to curb out-of-pocket expenditure. There is no cure for NASH, with liver transplantation remaining the last option for those who progress to end-stage liver disease (ESLD) or are detected with early-stage HCC. Thus, lifestyle modification remains the only viable option for many, but compliance and long-term adherence remain major challenges. In obese individuals, bariatric surgery and weight reduction have shown favourable results. In patients with less severe obesity, endoscopic bariatric metabolic therapies (EBMT) are rapidly emerging as less invasive therapies. However, access and acceptability remain poor for these weight reduction methods. Therefore, intense research is being conducted for potential newer drug classes with several agents currently in phase II or III of clinical development. Some of these have demonstrated promising results, such as a reduction in hepatic fat content, and attenuation of fibrosis with an acceptable tolerability profile in phase II studies. The developments in the management of NASH have been fairly encouraging. Further well-designed long-term prospective studies should be undertaken to generate evidence with definitive results.

Sociodemographic and genetic determinants of nonalcoholic fatty liver disease in type 2 diabetes mellitus patients

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) showed significant association with PNPLA3 rs738409 polymorphism in unrelated individuals. However, it is still unknown whether the relationship of NAFLD with PNPLA3 variant exists or not among subjects with type 2 diabetes mellitus (T2DM). Therefore, the study aimed to evaluate sociodemographic and genetic determinants of NAFLD in type 2 diabetics.

METHODS

The cross-sectional analytical study was conducted at the Department of Molecular Biology, Virtual University of Pakistan, Lahore, Pakistan, during 2019-2020. A total of 153 known cases of T2DM were enrolled using convenience sampling. After excluding patients (n = 24) with HCV, alcoholism, or missing information, data from 129 eligible diabetics with and without NAFLD were analyzed using SPSS. Odds ratios using crosstabs and adjusted odds ratios using binary and multinomial logistic regression were calculated to measure the risk of NAFLD.

RESULTS

Adults 18-35 years were 7.0%, 36-55 years were 64.3%, ≥ 56 years were 28.7%, and females were 66.7%. A total of 41.1% of patients had obesity, 52.7% had NAFLD, and 29.05% carried mutant G allele of rs738409 polymorphism. Among overall diabetics, NAFLD showed association with female (OR = 2.998, p = 0.007), illiterate (OR = 3.067, p = 0.005), and obese (OR = 2.211, p = 0.046) but not with PNPLA3 genotype under any model (all p = > 0.05). Among obese diabetics, NAFLD showed association with female (AOR = 4.010, p = 0.029), illiterate (AOR = 3.506, p = 0.037), GG + CG/CC (AOR = 3.303, p = 0.033), and GG/CG + CC (AOR = 4.547, p = 0.034) using binary regression and with female (AOR = 3.411, p = 0.051), illiterate (AOR = 3.323, p = 0.048), GG + CG/CC (AOR = 3.270, p = 0.029), and GG/CG + CC (AOR = 4.534, p = 0.024) using multinomial regression.

CONCLUSIONS

NAFLD and obesity were the most common comorbid diseases of T2DM. Gender female, being illiterate, and PNPLA3 rs738409 polymorphism were significant risk factors of NAFLD among obese diabetic patients.

Nonalcoholic Fatty Liver Disease (NAFLD): Pathogenesis and Noninvasive Diagnosis

The global prevalence of nonalcoholic fatty liver disease (NAFLD) or metabolic associated fatty liver disease (MAFLD), as it is now known, has gradually increased. NAFLD is a disease with a spectrum of stages ranging from simple fatty liver (steatosis) to a severe form of steatosis, nonalcoholic steatohepatitis (NASH), which could progress to irreversible liver injury (fibrosis) and organ failure, and in some cases hepatocellular carcinoma (HCC). Although a liver biopsy remains the gold standard for accurate detection of this condition, it is unsuitable for clinical screening due to a higher risk of death. There is thus an increased need to find alternative techniques or tools for accurate diagnosis. Early detection for NASH matters for patients because NASH is the marker for severe disease progression. This review summarizes the current noninvasive tools for NAFLD diagnosis and their performance. We also discussed potential and newer alternative tools for diagnosing NAFLD.

PNPLA3 downregulation exacerbates the fibrotic response in human hepatic stellate cells

Non-alcoholic steatohepatitis (NASH) results, in part, from the interaction of metabolic derangements with predisposing genetic variants, leading to liver-related complications and mortality. The strongest genetic determinant is a highly prevalent missense variant in patatin-like phospholipase domain-containing protein 3 (PNPLA3 p.I148M). In human liver hepatocytes PNPLA3 localizes to the surface of lipid droplets where the mutant form is believed to enhance lipid accumulation and release of pro-inflammatory cytokines. Less is known about the role of PNPLA3 in hepatic stellate cells (HSCs). Here we characterized HSC obtained from patients carrying the wild type (n = 8 C/C) and the heterozygous (n = 6, C/G) or homozygous (n = 6, G/G) PNPLA3 I148M and investigated the effect of genotype and PNPLA3 downregulation on baseline and TGF-β-stimulated fibrotic gene expression. HSCs from all genotypes showed comparable baseline levels of PNPLA3 and expression of the fibrotic genes α-SMA, COL1A1, TIMP1 and SMAD7. Treatment with TGF-β increased PNPLA3 expression in all 3 genotypes (~2-fold) and resulted in similar stimulation of the expression of several fibrogenic genes. In primary human HSCs carrying wild-type (WT) PNPLA3, siRNA treatment reduced PNPLA3 mRNA by 79% resulting in increased expression of α-SMA, Col1a1, TIMP1, and SMAD7 in cells stimulated with TGF-β. Similarly, knock-down of PNPLA3 in HSCs carrying either C/G or G/G genotypes resulted in potentiation of TGF-β induced expression of fibrotic genes. Knockdown of PNPLA3 did not impact fibrotic gene expression in the absence of TGF-β treatment. Together, these data indicate that the presence of the I148M PNPLA3 mutation in HSC has no effect on baseline activation and that downregulation of PNPLA3 exacerbates the fibrotic response irrespective of the genotype.

Association between PNPLA3 rs738409 polymorphism and nonalcoholic fatty liver disease: a systematic review and meta-analysis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a common disorder that is known to be the leading cause of chronic liver disease worldwide. This study aims to systematically review and meta-analyze the association between PNPLA3 rs738409 polymorphism and non-alcoholic fatty liver.

METHODS

Following a systematic review and meta-analysis method, articles without any time limitation, were extracted from SID, MagIran, IranDoc, Scopus, Embase, Web of Science (WoS), PubMed and ScienceDirect international databases. Random effects model was used for analysis, and heterogeneity of studies was investigated considering the I² index and using Comprehensive Meta-Analysis software.

RESULTS

The odds ratio of CC genotype in patients with non-alcoholic fatty liver demonstrates the protective effect of CC genotype with the ratio of 0.52, whereas CG genotype presents an increasing effect of CG genotype with the ratio of 0.19, and GG genotype also showed an increasing effect of GG genotype with the ratio of 1.05. Moreover, CG + GG genotypes as a single group demostrated an odds rartio of 0.88.

CONCLUSION

This meta-analysis highlights that people with CC genotype has 52% lower chance of developing non-alcoholic fatty liver disease, and those with CG genotype had 19% higher risk of developing non-alcoholic fatty liver. Those with GG genotype were 105% more likely to develop non-alcoholic fatty liver than others. Moreover, those present in a population with CG + GG genotypes were 88% more likely to have non-alcoholic fatty liver disease.

Diabetes and cardiometabolic risk in South Asian youth: A review

South Asians are at increased risk for developing type 2 diabetes and cardiovascular disease at lower body mass index compared to other ancestral groups. Many factors contribute to this increased risk, including genetics, maternal-fetal factors, diet, fitness, body composition, and unique pathophysiology. Increased cardiometabolic risk is also seen at younger ages in South Asian individuals as compared to their White counterparts. This risk persists in migrant communities outside of South Asia. With the growing prevalence of obesity, diabetes, and cardiovascular disease in the South Asian population, it is imperative that we had better understand the mechanisms underlying this increased risk and implement strategies to address this growing public health problem during childhood and adolescence.

Significance of Simple Steatosis: An Update on the Clinical and Molecular Evidence

Non-alcoholic fatty liver disease (NAFLD) is defined clinicopathologically by the accumulation of lipids in >5% of hepatocytes and the exclusion of secondary causes of fat accumulation. NAFLD encompasses a wide spectrum of liver damage, extending from simple steatosis or non-alcoholic fatty liver (NAFL) to non-alcoholic steatohepatitis (NASH)—the latter is characterized by inflammation and hepatocyte ballooning degeneration, in addition to the steatosis, with or without fibrosis. NAFLD is now the most common cause of chronic liver disease in Western countries and affects around one quarter of the general population. It is a multisystem disorder, which is associated with an increased risk of type 2 diabetes mellitus as well as liver- and cardiovascular-related mortality. Although earlier studies had suggested that NAFL is benign (i.e., non-progressive), cumulative evidence challenges this dogma, and recent data suggest that nearly 25% of those with NAFL may develop fibrosis. Importantly, NAFLD patients are more susceptible to the toxic effects of alcohol, drugs, and other insults to the liver. This is likely due to the functional impairment of steatotic hepatocytes, which is virtually undetectable by current clinical tests. This review provides an overview of the current evidence on the clinical significance of NAFL and discusses the molecular basis for NAFL development and progression.

PNPLA3 and TM6SF2 polymorphisms in Brazilian patients with nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is becoming the most common chronic liver disease worldwide, with significant morbidity associated with nonalcoholic steatohepatitis (NASH). Genome-wide association studies demonstrated that the variants rs738409 C/G in the PNPLA3 and rs58542926 C/T in the TM6SF2 genes are determinants of inter-individual and ethnicity-related differences in hepatic fat content and NAFLD progression.

AIM

To investigate PNPLA3 and TM6SF2 genotype frequency and their association with NAFLD development and progression in Brazilian patients.

METHODS

This cross-sectional case-control study enrolled 285 individuals from the Gastroenterology and Hepatology clinics at a university hospital in Brazil. The case patients (n = 148) were confirmed to have NAFLD by the identification of hepatic steatosis on ultrasonography and exclusion of other causes of liver disease. According to the clinical protocol, patients underwent liver biopsy when at high risk for NASH and/or advanced fibrosis (n = 65). Steatohepatitis was confirmed in 54 patients. Individuals who did not have biopsy indication or NASH on histology were considered to have simple steatosis (n = 94). The control group (n = 137) was selected among patients that attended the Intestinal Disease clinic and was composed of subjects without abnormalities on abdominal ultrasonography and normal liver biochemical tests. All individuals underwent PNPLA3 and TM6SF2 genotype analysis.

RESULTS

PNPLA3 CC, CG and GG genotype frequencies were 37%, 44% and 19%, respectively, in NAFLD patients and were 58%, 31% and 10% in controls (P < 0.001). In a model adjusted for gender, age, body mass index and type 2 diabetes mellitus, the G allele increased the chance of NAFLD (OR = 1.69, 95%CI: 1.21-2.36, P = 0.002) and NASH (OR = 3.50, 95%CI: 1.84-6.64, P < 0.001). The chance of NASH was even higher with GG homozygosis (OR = 5.53, 95%CI: 2.04-14.92, P = 0.001). No association was found between G allele and the features of metabolic syndrome. In histological assessment, PNPLA3 genotype was not associated with steatosis grade, although GG homozygosis increased the chance of significant NASH activity (OR = 17.11, 95%CI: 1.87-156.25, P = 0.01) and fibrosis (OR = 7.42, 95%CI: 1.55-34.47, P = 0.01) in the same adjusted model. TM6SF2 CC, CT and TT genotype frequencies were 83%, 15% and 0.7%, respectively, in NAFLD patients and were 84%, 16% and 0.7% in controls (P = 0.78). The T allele presence was not associated with NAFLD or NASH, and was not associated with histological features.

CONCLUSION

PNPLA3 may be involved in susceptibility and progression of NAFLD and NASH in the Brazilian population. More advanced histological liver disease was associated with the G allele. The TM6SF2 genetic variants were not associated with NAFLD susceptibility and progressive histological forms in the population studied, but further studies are required to confirm these findings.

Research status and prgoress of nonalcoholic fatty pancreatic disease

Nonalcoholic fatty pancreatic disease (NAFPD) is a disease characterized by an increase in pancreatic fat accumulation. It is a component of the metabolic syndrome and often coexists with nonalcoholic fatty liver disease. Once the diagnosis is established, it is closely related to acute and chronic pancreatitis, type 2 diabetes mellitus, pancreatic fibrosis, and pancreatic cancer. In recent years, it has been confirmed that NAFPD is closely related to cardiovascular disease, liver fibrosis, and liver cancer. The prevalence of NAFPD ranges between 11% and 69%, and increases with age. It is worth noting that the prevalence in obese children is twice as high as that in non-obese children. The high prevalence rate and complexity of the disease have aroused people's high attention. Therefore, to improve the understanding of NAFPD, fully understand the clinical significance of NAFPD, and further study its pathogenesis, diagnosis, and treatment require the collaboration and joint efforts of multiple disciplines, including hepatopathy, gastroenterology, endocrine metabolism, cardiovascular disease, imaging, pathology, and others. In this paper, we review the clinical significance, pathogenesis, and imaging diagnosis of NAFPD and propose our personal understanding of the key points in future research.

Review article: the emerging role of genetics in precision medicine for patients with non-alcoholic steatohepatitis

BACKGROUND

Non-alcoholic steatohepatitis (NASH) is a severe form of non-alcoholic fatty liver disease (NAFLD) characterised by liver fat accumulation, inflammation and progressive fibrosis. Emerging data indicate that genetic susceptibility increases risks of NAFLD, NASH and NASH-related cirrhosis.

AIMS

To review NASH genetics and discuss the potential for precision medicine approaches to treatment.

METHOD

PubMed search and inclusion of relevant literature.

RESULTS

Single-nucleotide polymorphisms in PNPLA3, TM6SF2, GCKR, MBOAT7 and HSD17B13 are clearly associated with NASH development or progression. These genetic variants are common and have moderate-to-large effect sizes for development of NAFLD, NASH and hepatocellular carcinoma (HCC). The genes play roles in lipid remodelling in lipid droplets, hepatic very low-density lipoprotein (VLDL) secretion and de novo lipogenesis. The PNPLA3 I148M variant (rs738409) has large effects, with approximately twofold increased odds of NAFLD and threefold increased odds of NASH and HCC per allele. Obesity interacts with PNPLA3 I148M to elevate liver fat content and increase rates of NASH. Although the isoleucine-to-methionine substitution at amino acid position 148 of the PNPLA3 enzyme inactivates its lipid remodelling activity, the effect of PNPLA3 I148M results from trans-repression of another lipase (ATGL/PNPLA2) by sequestration of a shared cofactor (CGI-58/ABHD5), leading to decreased hepatic lipolysis and VLDL secretion. In homozygous Pnpla3 I148M knock-in rodent models of NAFLD, targeted PNPLA3 mRNA knockdown reduces hepatic steatosis, inflammation and fibrosis.

CONCLUSION

The emerging genetic and molecular understanding of NASH paves the way for novel interventions, including precision medicines that can modulate the activity of specific genes associated with NASH.

PNPLA3-A Potential Therapeutic Target for Personalized Treatment of Chronic Liver Disease

Patatin-like phospholipase domain-containing protein 3 (PNPLA3) is a lipid droplet-associated protein that has been shown to have hydrolase activity toward triglycerides and retinyl esters. The first evidence of PNPLA3 being associated with fatty liver disease was revealed by a genome-wide association study (GWAS) of Hispanic, African American, and European American individuals in the Dallas Heart Study back in 2008. Since then, numerous GWAS reports have shown that PNPLA3 rs738409[G] (148M) variant is associated with hepatic triglyceride accumulation (steatosis), inflammation, fibrosis, cirrhosis, and even hepatocellular carcinoma regardless of etiologies including alcohol- or obesity-related and others. The frequency of PNPLA3(148M) variant ranges from 17% in African Americans, 23% in European Americans, to 49% in Hispanics in the Dallas Heart Study. Due to high prevalence of obesity and alcohol consumption in modern societies, the PNPLA3(148M) gene variant and environment interaction poses a serious concern for public health, especially chronic liver diseases including alcohol-related liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD). Therefore, PNPLA3(148M) variant is a potential therapeutic target for chronic liver disease in the rs738409 allele carriers. Currently, there is no approved drug specifically targeting the PNPLA3(148M) variant yet. With additional mechanistic studies, novel therapeutic strategies are expected to be developed for the treatment of the PNPLA3(148M) variant-associated chronic liver diseases in the near future.

Liver steatosis and dyslipidemia after HCV eradication by direct acting antiviral agents are synergistic risks of atherosclerosis

Aim

We comprehensively analyzed how hepatitis C virus (HCV) eradication by interferon (IFN)-free direct-acting-antiviral-agents (DAAs) affects liver steatosis and atherogenic risk.

Methods

Patients treated with IFN-free-DAAs who underwent transient elastography before and at 24-weeks post-treatment, including controlled attenuation parameter (CAP), and achieved sustained viral response (SVR) were enrolled. The association between changes in liver steatosis, lipid-metabolism, and genetic and clinical factors was analyzed.

Results

A total of 117 patients were included. The mean CAP and low-density lipoprotein cholesterol (LDL-C) levels were significantly elevated at SVR24. However, baseline LDL-C and CAP values were significantly negatively correlated with changes in these values after HCV eradication, indicating that in patients with high baseline values, the values generally decreased after HCV eradication. Mean small-dense LDL-C (sdLDL-C), which has greater atherogenic potential, was significantly elevated only in patients with both dyslipidemia (LDL-C >140 mg/dL) and liver steatosis (CAP >248 dB/m) at SVR24. Those patients had significant higher baseline BMI, LDL-C, and total-cholesterol levels.

Conclusions

Generally, successful HCV eradication by IFN-free-DAAs decreases CAP and LDL-C in patients with high baseline values. However, elevated LDL-C was accompanied with elevated sdLDL-C only in patients with liver steatosis and dyslipidemia at SVR24; therefore, those patients may require closer monitoring.

Fatty pancreas: A possible risk factor for pancreatic cancer in animals and humans

Obesity, type 2 diabetes mellitus (T2DM) and aging are associated with pancreatic cancer risk, but the mechanisms of pancreatic cancer development caused by these factors are not clearly understood. Syrian golden hamsters are susceptible to N‐nitrosobis(2‐oxopropyl)amine (BOP)‐induced pancreatic carcinogenesis. Aging, BOP treatment and/or a high‐fat diet cause severe and scattered fatty infiltration (FI) of the pancreas with abnormal adipokine production and promote pancreatic ductal adenocarcinoma (PDAC) development. The KK‐A^y mouse, a T2DM model, also develops severe and scattered FI of the pancreas. Treatment with BOP induced significantly higher cell proliferation in the pancreatic ducts of KK‐A^y mice, but not in those of ICR and C57BL/6J mice, both of which are characterized by an absence of scattered FI. Thus, we hypothesized that severely scattered FI may be involved in the susceptibility to PDAC development. Indeed, severe pancreatic FI, or fatty pancreas, is observed in humans and is associated with age, body mass index (BMI) and DM, which are risk factors for pancreatic cancer. We analyzed the degree of FI in the non‐cancerous parts of PDAC and non‐PDAC patients who had undergone pancreatoduodenectomy by histopathology and demonstrated that the degree of pancreatic FI in PDAC cases is significantly higher than that in non‐PDAC controls. Moreover, the association with PDAC is positive, even after adjusting for BMI and the prevalence of DM. Accumulating evidence suggests that pancreatic FI is involved in PDAC development in animals and humans, and further investigations to clarify the genetic and environmental factors that cause pancreatic FI are warranted.

Association of Ischemic Cardiovascular Disease with Inadequacy of Liver Store of Retinol in Elderly Individuals

Objective

Vitamin A antioxidant role has an important relationship with the metabolic processes of aging and cardiovascular disease (CVD). This study aimed at assessing the liver store of retinol in elderly individuals who died from cardiovascular disease and its relationship with liver weight and body weight.

Methods and Results

This is a cross-sectional study conducted in necropsied individuals, aged 60 years or over, until 48 hours postmortem. The study assessed 65 elderly individuals who died from ischemic heart diseases (G1), cerebrovascular diseases (G2), other forms of heart disease (G3), or infectious heart diseases (G4). Twenty percent had inadequate liver store of retinol. G1 showed lower median of liver store of retinol when compared to G3 (p < 0.001), and G3 showed the highest median when compared to G2 (p = 0.007). A significant association was observed between inadequate liver store of retinol and death by ischemic CVD (G1) (p = 0.001) with an odds ratio of 10.38. It was observed that individuals with higher body weight and liver weight showed lower liver store of retinol with significant differences (p = 0.027 and p = 0.026).

Conclusion

Ischemic CVD and increased body weight and liver weight are related to a greater impairment of the liver store of retinol.

Network analyses identify liver-specific targets for treating liver diseases

We performed integrative network analyses to identify targets that can be used for effectively treating liver diseases with minimal side effects. We first generated co-expression networks (CNs) for 46 human tissues and liver cancer to explore the functional relationships between genes and examined the overlap between functional and physical interactions. Since increased de novo lipogenesis is a characteristic of nonalcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC), we investigated the liver-specific genes co-expressed with fatty acid synthase (FASN). CN analyses predicted that inhibition of these liver-specific genes decreases FASN expression. Experiments in human cancer cell lines, mouse liver samples, and primary human hepatocytes validated our predictions by demonstrating functional relationships between these liver genes, and showing that their inhibition decreases cell growth and liver fat content. In conclusion, we identified liver-specific genes linked to NAFLD pathogenesis, such as pyruvate kinase liver and red blood cell (PKLR), or to HCC pathogenesis, such as PKLR, patatin-like phospholipase domain containing 3 (PNPLA3), and proprotein convertase subtilisin/kexin type 9 (PCSK9), all of which are potential targets for drug development.

PNPLA3 polymorphism increases risk for and severity of chronic hepatitis C liver disease

AIM

To examine the association of PNPLA3 polymorphisms in chronic hepatitis C patients and development of liver disease spectrum.

METHODS

Literature was searched systematically from PubMed/MEDLINE, EMBASE, and Cochrane search engines for full-length articles written in English that examined PNPLA3 polymorphism in chronic hepatitis C (CHC) patients. Studies evaluating the association of PNPLA3 polymorphism spectrum (fatty liver, steatohepatitis, cirrhosis, and hepatocellular carcinoma) of CHC were included. Pooled data are reported as OR with 95%CI. Our study endpoint was the risk of the entire liver disease spectrum including: Steatosis/fatty liver, cirrhosis, and hepatocellular carcinoma in CHC patients with PNPLA3 polymorphisms.

RESULTS

Of 380 studies identified, a total of 53 studies were included for full-text review. Nineteen on chronic hepatitis C were eligible for analysis. Pooled ORs for rs738409 GG compared to CC and CG among patients with fatty liver was 2.214 (95%CI: 1.719-2.853). ORs among advanced fibrosis/cirrhosis were 1.762 (95%CI: 1.258-2.468). Similar odds ratios among hepatocellular carcinoma patients were 2.002 (95%CI: 1.519-2.639). Pooled ORs for rs738409 GG and CG compared to CC among patients with fatty liver were 1.750 (95%CI: 1.542-1.986). Pooled ORs for advanced fibrosis/cirrhosis patients were 1.613 (95%CI: 1.211-2.147). All analyses were homogenous and without publication bias except one. The associations were maintained after adjusting for publication bias and heterogeneity.

CONCLUSION

PNPLA3 polymorphisms have strong association with increased risk and severity of the liver disease spectrum in CHC patients.