The Association between Angiotensin II Type 1 Receptor Gene A1166C Polymorphism and Non-alcoholic Fatty Liver Disease and Its Severity

Prevalence of non-alcoholic fatty liver and its related factors in Iran: Systematic review and meta-analysis

Non-alcoholic fatty liver disease (NAFLD) is a systemic disorder with a complex multifactorial and heterogeneous pathogenesis and has become the most common cause of chronic liver disease in many countries around the world. Numerous studies in Iran have presented different results on the prevalence and risk factors of NAFLD, in this study, which has been done in a systematic review and meta-analysis, provides a good estimate of the prevalence and risk factors of the disease in Iran. Following the peer review of electronic search strategies (PRESS and the preferred reporting items for systematic reviews and meta-analyses [PRISMA] statement, we searched Web of Science, PubMed, Embase, Scopus, and Persian scientific searcher (Elmnet) from inception to September 19, 2022. In the present study, 71 articles were reviewed for qualitative and meta-analysis. The overall mean prevalence of NAFLD in children studies was 22.4% (95% confidence interval [CI]: 10.9% to 33.9%). The prevalence was notably higher in adult studies 40.5% (95% CI: 35.1% to 46%). In 24 studies, the association between NAFLD and sex was reported, 10 of which showed significant relationships. Out of 46 studies observed that NAFLD prevalence increased significantly with body mass index (BMI). Eight out of 14 studies reported significant associations between FBS and NAFLD in children's studies. Though Iran has a high NAFLD prevalence compared to most areas, and due to the unfavorable situation of risk factors contributing to the NAFLD, it is necessary to take the necessary interventions to control these risk factors and prevent NAFLD.

Comprehensive Strategy for Identifying Extracellular Vesicle Surface Proteins as Biomarkers for Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a liver disorder that has become a global health concern due to its increasing prevalence. There is a need for reliable biomarkers to aid in the diagnosis and prognosis of NAFLD. Extracellular vesicles (EVs) are promising candidates in biomarker discovery, as they carry proteins that reflect the pathophysiological state of the liver. In this review, we developed a list of EV proteins that could be used as diagnostic biomarkers for NAFLD. We employed a multi-step strategy that involved reviewing and comparing various sources of information. Firstly, we reviewed papers that have studied EVs proteins as biomarkers in NAFLD and papers that have studied circulating proteins as biomarkers in NAFLD. To further identify potential candidates, we utilized the EV database Vesiclepedia.org to qualify each protein. Finally, we consulted the Human Protein Atlas to search for candidates' localization, focusing on membrane proteins. By integrating these sources of information, we developed a comprehensive list of potential EVs membrane protein biomarkers that could aid in diagnosing and monitoring NAFLD. In conclusion, our multi-step strategy for identifying EV-based protein biomarkers for NAFLD provides a comprehensive approach that can also be applied to other diseases. The protein candidates identified through this approach could have significant implications for the development of non-invasive diagnostic tests for NAFLD and improve the management and treatment of this prevalent liver disorder.

Angiotensin receptor blockers might be protective against hepatic steatosis after liver transplantation

BACKGROUND

Hepatic steatosis is an increasing complication in liver transplant recipients. Currently, there is no pharmacologic therapy for treatment of hepatic steatosis after liver transplantation. The aim of this study was to determine the association between use of angiotensin receptor blockers (ARB) and hepatic steatosis in liver transplant recipients.

METHODS

We conducted a case-control analysis on data from Shiraz Liver Transplant Registry. Liver transplant recipients with and without hepatic steatosis were compared for risk factors including use of ARB.

RESULTS

A total of 103 liver transplant recipients were included in the study. Thirty five patients treated with ARB and 68 patients (66%) did not receive these medications. In univariate analysis, ARB use (P = 0.002), serum triglyceride (P = 0.006), weight after liver transplantation (P = 0.011) and etiology of liver disease (P = 0.008) were associated with hepatic steatosis after liver transplantation. In multivariate regression analysis, ARB use was associated with lower likelihood of hepatic steatosis in liver transplant recipients (OR = 0.303, 95% CI: 0.117-0.784; P = 0.014). Mean duration of ARB use (P = 0.024) and mean cumulative daily dose of ARB (P = 0.015) were significantly lower in patients with hepatic steatosis.

CONCLUSION

Our study showed that ARB use was associated with reduced incidence of hepatic steatosis in liver transplant recipients.

Update on Non-Alcoholic Fatty Liver Disease-Associated Single Nucleotide Polymorphisms and Their Involvement in Liver Steatosis, Inflammation, and Fibrosis: A Narrative Review

Genetic factors are involved in the development, progression, and severity of NAFLD. Polymorphisms in genes regulating liver functions may increase liver susceptibility to NAFLD. Therefore, we conducted this literature study to present recent findings on NAFLD-associated polymorphisms from published articles in PubMed from 2016 to 2021. From 69 selected research articles, 20 genes and 34 SNPs were reported to be associated with NAFLD. These mutated genes affect NAFLD by promoting liver steatosis (PNPLA3, MBOAT7, TM2SF6, PTPRD, FNDC5, IL-1B, PPARGC1A, UCP2, TCF7L2, SAMM50, IL-6, AGTR1, and NNMT), inflammation (PNPLA3, TNF-α, AGTR1, IL-17A, IL-1B, PTPRD, and GATAD2A), and fibrosis (IL-1B, PNPLA3, MBOAT7, TCF7L2, GATAD2A, IL-6, NNMT, UCP, AGTR1, and TM2SF6). The identification of these genetic factors helps to better understand the pathogenesis pathways of NAFLD

Clinical Value and Role of miR-129-5p in Non-Alcoholic Fatty Liver Disease

This study was to evaluate the expression of miR-129-5p in non-alcoholic fatty liver (NAFLD) patients and its clinical value and explore its regulatory effect on insulin resistance (IR). A total of 117 NAFLD patients and 110 healthy controls were included. The levels of miR-129-5p were detected by qRT-PCR. To assess the diagnostic value of miR-129-5p for NAFLD, the receiver operating characteristic curve (ROC) was established. C57Bl/6 mice were supplied with high-fat diet to establish NAFLD model. Intraperitoneal insulin tolerance test (IPITT) was carried out to evaluate the effect of miR-129-5p on IR in NAFLD animal model. miR-129-5p was highly expressed in the serum of NAFLD patients, and patients with HOMA-IR ≥2.5 had higher level of miR-129-5p than those with HOMA-IR <2.5. miR-129-5p had the ability to differentiate NAFLD patients from healthy individuals and might be associated with the development of IR. Serum miR-129-5p was positively correlated with the levels of HOMA-IR, BMI, total cholesterol (TC), and triglyceride (TG) in NAFLD patients. Downregulation of miR-129-5p regulates lipid metabolism and insulin sensitivity in NAFLD mice model. MiR-129-5p was upregulated in NAFLD patients and might be a potential diagnostic biomarker. The regulatory effect of miR-129-5p on NAFLD may function by regulating lipid accumulation and insulin sensitivity.

Characterization of biopsy proven non-alcoholic fatty liver disease in healthy non-obese and lean population of living liver donors: The impact of uric acid

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is frequently seen among non-obese overweight individuals and lean subjects (those with normal body mass index). This study aimed to investigate prevalence and risk factors of biopsy proven NAFLD in a cluster of healthy non-obese and lean individuals.

METHODS AND MATERIALS

In a retrospective study, adult (>18 years) apparently healthy individuals who had donated liver to pediatric patients between July 2012 and October 2018 were included. Non-obese and lean individuals were defined as BMI<30kg/m² and BMI<25kg/m², respectively.

RESULTS

Totally 310 patients were included. Seventy-six individuals (24.5%) had NAFL and 30 patients (9.67%) had non-alcoholic steatohepatitis (NASH) among non-obese population. In multivariate regression analysis, only higher BMI was marginally associated with NASH in non-obese compared to those without NASH (Odds ratio: 2.52, 95% CI: 0.097-6.54; P=0.05). Totally, 246 individuals were lean. 55 individuals (22.3%) had NAFL and 20 individuals (8.2%) had NASH in their liver biopsies. In univariate analysis, serum triglyceride, cholesterol, LDL, ALT, alkaline phosphatase and uric acid were associated with NAFL among lean individuals (P<0.05). In regression analysis, serum uric acid was associated with NAFL (Odds ratio: 1.70, 95% CI: 1.18-2.45; P=0.004) and NASH in lean individuals (Odds ratio: 1.98, 95% CI: 1.27-3.10; P=0.003).

CONCLUSION

NAFLD/NASH is prevalent even in a healthy lean population when evaluated by liver biopsy. Higher BMI and serum uric acid were two major risks of NAFLD/NASH in non-obese and lean individuals.

Tanshinone IIA Can Inhibit Angiotensin II-Induced Proliferation and Autophagy of Vascular Smooth Muscle Cells via Regulating the MAPK Signaling Pathway

To examine the effect of tanshinone IIA on Angiotensin II (Ang II)-induced proliferation and autophagy in vascular smooth muscle cells (VSMCs) and the related mechanism. VSMCs were treated with Ang II with or without tanshinone IIA (1, 5 and 10 µg/mL), and the proliferation, apoptosis in cells with different treatment were examined by methylthiazolyl tetrazolium (MTT) and flow cytometry methods. Moreover, the expression of autophagy related proteins and mitogen-activated protein kinase (MAPK) signaling molecules were examined by RT-quantitative (q)PCR and Western blot methods. Ang II induced significantly increase in the proliferation and autophagy of VSMCs, and the MAPK signaling was activated. Tanshinone IIA can attenuate Ang II-induced effects via down-regulating the MAPK signaling pathway. Tanshinone IIA can inhibit Ang II-induced proliferation and autophagy of VSMCs via regulating the MAPK signaling pathway.

An AGTR1 Variant Worsens Nonalcoholic Fatty Liver Disease and the Metabolic Syndrome

Nonalcoholic fatty liver disease and hypertension are closely related but there has been little genetic evidence to link them. In this issue, Musso et al. provide evidence that a common variant in AGTR1 (A1166C) is associated with both incident hypertension and nonalcoholic fatty liver disease, as well as nonalcoholic steatohepatitis, fibrosis, dyslipidemia, and insulin resistance. AGTR1 is strongly expressed in adipose, liver, and arteries. The mechanism of this gain-of-function variant is unclear but may include adipose or endothelial dysfunction and immune activation. Despite previous unsuccessful clinical trials of angiotensin receptor blockers in nonalcoholic steatohepatitis, individuals with the rs5186A>C variant may have greater benefit from this therapy.

Interaction Between AGTR1 and PPARγ Gene Polymorphisms on the Risk of Nonalcoholic Fatty Liver Disease

AIMS

Nonalcoholic fatty liver disease (NAFLD) is an important public health issue worldwide. Several recent studies have reported that peroxisome proliferator-activated receptor-γ (PPARγ) and angiotensin II type 1 receptor (AGTR1) variants are associated with NAFLD occurrence, but the results have been inconsistent. The aim of this study was to analyze the interactions between PPARγ and AGTR1 polymorphisms and their associations with NAFLD in Chinese adults.

METHODS

Seven single nucleotide polymorphisms (SNPs) of the PPARγ gene and 5 SNPs of the AGTR1 gene were selected and genotyped in 1591 unrelated Chinese adults. The SNPAssoc package of R was used to examine the relationships between the selected SNPs and NAFLD.

RESULTS

After adjusting the covariance, the results from the overdominant model showed that participants carrying the T/C genotype of rs2638360 in AGTR1 have a decreased risk of NAFLD compared with those with T/T-C/C genotypes (odds ratio: 0.70, 95% confidence interval: 0.49-1.00). However, our results showed that none of the selected PPARγ variants were significantly associated with the risk of NAFLD after applying a false discovery rate correction. Among the 12 selected SNPs from PPARγ and AGTR1, model-based multifactor dimensionality reduction (MB-MDR) analyses for gene-gene interactions revealed that all the models were significantly associated with the increased risk of NAFLD (p < 0.05) except the 2-, 10-, 11-, and 12-locus models. Further, among the 10 SNPs negatively associated with NAFLD, the four-locus model (rs13431696 and rs3856806 in PPARγ, and rs5182, rs1492100 in ATGR1) and the five-locus model (rs9817428, rs1175543, rs13433696, and rs2920502 in PPARγ, and rs1492100 in ATGR1) were closely related with NAFLD susceptibility (p = 0.019 and p = 0.048, respectively).

CONCLUSION

Our present study suggests that interactions among multiple AGTR1 and PPARγ polymorphisms are associated with the risk of NAFLD in the Chinese population.