Predictive value of angiopoietin-like protein 8 in metabolic dysfunction-associated fatty liver disease and its progression:A case-control study

BACKGROUND The prevalence of metabolic dysfunction-associated fatty liver disease(MAFLD)is rapidly increasing,currently affecting approximately 25%of the global population.Liver fibrosis represents a crucial stage in the development of MAFLD,with advanced liver fibrosis elevating the risks of cirrhosis and hepatocellular carcinoma.Simple serum markers are less effective in diagnosing liver fibrosis compared to more complex markers.However,imaging techniques like transient elastography face limitations in clinical application due to equipment and technical constraints.Consequently,it is imperative to identify a straightforward yet effective method for assessing MAFLD-associated liver fibrosis.AIM To investigate the predictive value of angiopoietin-like protein 8(ANGPTL8)in MAFLD and its progression.METHODS We analyzed 160 patients who underwent abdominal ultrasonography in the Endocrinology Department,Xiaogan Central Hospital affiliated to Wuhan University of Science and Technology,during September 2021-July 2022.Using abdominal ultrasonography and MAFLD diagnostic criteria,among the 160 patients,80 patients(50%)were diagnosed with MAFLD.The MAFLD group was divided into the liver fibrosis group(n=23)and non-liver fibrosis group(n=57)by using a cut-off fibrosis-4 index≥1.45.Logistical regression was used to analyze the risk of MAFLD and the risk factors for its progression.Receiver operating characteristic curves were used to evaluate the predictive value of serum ANGPTL8 in MAFLD and its progression.RESULTS Compared with non-MAFLD patients,MAFLD patients had higher serum ANGPTL8 and triglyceride-glucose(TyG)index(both P<0.05).Serum ANGPTL8(r=0.576,P<0.001)and TyG index(r=0.473,P<0.001)were positively correlated with MAFLD.Serum ANGPTL8 was a risk factor for MAFLD[odds ratio(OR):1.123,95%confidence interval(CI):1.066-1.184,P<0.001).Serum ANGPTL8 and ANGPTL8+TyG index predicted MAFLD[area under the curve(AUC):0.832 and 0.886,respectively;both P<0.05].Compared with MAFLD patients without fibrosis,those with fibrosis had higher serum ANGPTL8 and TyG index(both P<0.05),and both parameters were positively correlated with MAFLD-associated fibrosis.Elevated serum ANGPTL8(OR:1.093,95%CI:1.044-1.144,P<0.001)and TyG index(OR:2.383,95%CI:1.199-4.736,P<0.013)were risk factors for MAFLD-associated fibrosis.Serum ANGPTL8 and ANGPTL8+TyG index predicted MAFLD-associated fibrosis(AUC:0.812 and 0.835,respectively;both P<0.05).CONCLUSION The serum levels of ANGPTL8 are elevated and positively correlated with MAFLD.They can serve as predictors for the risk of MAFLD and liver fibrosis,with the ANGPTL8+TyG index potentially exhibiting even higher predictive value.

Recombinant angiopoietin-like protein 4 attenuates intestinal barrier structure and function injury after ischemia/reperfusion

BACKGROUND Intestinal barrier breakdown,a frequent complication of intestinal ischemiareperfusion(I/R)including dysfunction and the structure changes of the intestine,is characterized by a loss of tight junction and enhanced permeability of the intestinal barrier and increased mortality.To develop effective and novel therapeutics is important for the improvement of outcome of patients with intestinal barrier deterioration.Recombinant human angiopoietin-like protein 4(rhANGPTL4)is reported to protect the blood-brain barrier when administered exogenously,and endogenous ANGPTL4 deficiency deteriorates radiationinduced intestinal injury.AIM To identify whether rhANGPTL4 may protect intestinal barrier breakdown induced by I/R.METHODS Intestinal I/R injury was elicited through clamping the superior mesenteric artery for 60 min followed by 240 min reperfusion.Intestinal epithelial(Caco-2)cells and human umbilical vein endothelial cells were challenged by hypoxia/reoxygenation to mimic I/R in vitro.RESULTS Indicators including fluorescein isothiocyanate-conjugated dextran(4 kilodaltons;FD-4)clearance,ratio of phosphorylated myosin light chain/total myosin light chain,myosin light chain kinase and loss of zonula occludens-1,claudin-2 and VE-cadherin were significantly increased after intestinal I/R or cell hypoxia/reoxygenation.rhANGPTL4 treatment significantly reversed these indicators,which were associated with inhibiting the inflammatory and oxidative cascade,excessive activation of cellular autophagy and apoptosis and improvement of survival rate.Similar results were observed in vitro when cells were challenged by hypoxia/reoxygenation,whereas rhANGPTL4 reversed the indicators close to normal level in Caco-2 cells and human umbilical vein endothelial cells significantly.CONCLUSION rhANGPTL4 can function as a protective agent against intestinal injury induced by intestinal I/R and improve survival via maintenance of intestinal barrier structure and functions.

过表达人血管生成素样蛋白4对食管癌EC9706细胞生长的影响(英文)

Objective:The aim of the study was to construct the eukaryotic expression vector of human angiopoietin-like protein 4(ANGPTL4) and observe the effect of ANGPTL4 overexpression on the growth of esophageal carcinoma EC9706 cells.Methods:Total RNA was extracted from normal hepatic tissue,and ANGPTL4 cDNA was amplified by RT-PCR.The PCR product was doubly digested by XbaI and SalI,and then recombined into eukaryotic expression vector.Then,pIRES-GFP-ANGPTL4 was obtained by G418 selection,then pIRES-GFP-ANGPTL4 and pIRES-GFP were transfected into EC9706 cells with lipidosome-packaged method.Meanwhile,the transfected cells were selected by G418,and then stable transfected cell lines were obtained.ANGPTL4 mRNA levels,the cell cycles and growth curves of EC9706 cells in experiment group(transfected with pIRES-GFP-ANGPTL4),empty vector group(transfected with pIRES-GFP) and blank control group(EC9706 cells without transfection) were detected with RT-PCR,flow cytometry and MTT methods,respectively.Results:Eukaryotic ANGPTL4 expression vector pIRES-GFP-ANGPTL4 was successfully constructed.The ANGPTL4 mRNA level(0.21 ± 0.03) in experiment group was significantly higher than that of the empty vector group(0.04 ± 0.008) and the blank control group(0.05 ± 0.007),with significant differences(P < 0.01).The proportion of cells in S phase in experiment group was significantly different with those of the other two groups(P < 0.05).The cell growth of EC9706 cells in experiment group was slower than those of the other two groups.From the third day,the differences began to be significant.Conclusion:ANGPTL4 overexpression in esophageal carcinoma EC9706 cells could inhibit the growth of EC9706 cells.

Lipopolysaccharide-induced podocyte injury is regulated by calcineurin/NFAT and TLR4/MyD88/NF-κB signaling pathways through angiopoietin-like protein 4

Podocyte injury is an important cause of proteinuria.Angiopoietin-like protein 4(Angptl4)is a secreted glycoprotein and has a role in proteinuria.However,the exact role of Angptl4 in podocyte injury and its upstream regulators has not been clarified.In this study,we used lipopolysaccharide(LPS)-induced mice and cultured podocytes as podocyte injury models.Our results indicated that LPS increased the expression of podocyte Angptl4 in vivo and in vitro.Furthermore,we showed that Angptl4 overexpression deteriorated LPS-induced podocyte injury by inducing podocyte cytoskeleton rearrangement,reducing the expression of synaptopodin while Angptl4 knockdown alleviated LPS-induced podocyte injury.In addition,we found that inhibitors and siRNA targeting TLR4/MyD88/NF-κB signaling inhibited the upregulation of Angptl4 in LPS-induced podocytes.Moreover,inhibitors and siRNA targeting calcineurin/NFAT signaling also relieved LPS-induced Angptl4 expression and podocyte injury in vivo and in vitro.Taken together,our study has elucidated that both of the TLR4/MyD88/NF-κB and calcineurin/NFAT signaling mediate the upregulation of Angptl4 in LPS-induced podocytes,which has important implications for further understanding the molecular mechanism of LPS-induced podocyte injury.

Angptl4基因缺失可改善脂质代谢与抑制泡沫细胞形成避免动脉粥样硬化

血管生成素样蛋白4（angiopoietin-like protein family 4，Angptl 4）是血管内皮生长因子家族成员，主要在脂肪和肝脏表达，在心、肾等组织也有表达，可以通过抑制脂蛋白脂肪酶活性而调节脂质代谢。日本熊本大学的Adachi及其同事通过ApoE（-／-）Angptl4（-／-）小鼠来研究Angptl4基因缺失对脂质代谢和动脉粥样硬化的影响。其结果发表于美国的《生物化学及生物物理研究通讯杂志》（Biochem Biophys Res Commun，2008，15）上。

早期糖尿病慢性肾脏疾病患者血清血管生成素样蛋白4水平及吡格列酮影响的观察

目的探讨早期糖尿病慢性肾脏疾病(CKD)患者血清血管生成素样蛋白4(ANGPTL4)水平及吡格列酮(PGZ)对其影响。方法选取体检健康者92名为健康对照(NC)组、新诊断单纯T2DM患者89例为T2DM组和早期CKD患者90例为CKD组。将CKD组采用随机数字表法进一步分为联合吡格列酮治疗(PGZ)亚组45例和联合格列美脲治疗(GLI)亚组45例。采用ELISA检测血清ANGPTL4水平,观察治疗前后CKD患者血清ANGPTL4水平变化。结果 NC、T2DM、CKD组血清ANGPTL4水平逐渐降低[(34.8±4.75)vs(31.1±3.65)vs(27.1±3.52)ng/ml,P<0.05或P<0.01]。血清ANGPTL4水平与超氧化物岐化酶(SOD)、TG呈正相关(r=0.635、0.526,P<0.05或P<0.01),与BMI、FPG、HbA1c、高敏C反应蛋白(hsC-RP)、UAlb/Cr、VEGF、FIns、胰岛素抵抗指数(HOMA-IR)呈负相关(r=-0.502、-0.624、-0.542、-0.520、-0.538、-0.566、-0.576、-0.509,P<0.05或P<0.01)。治疗后PGZ亚组血清ANGPTL4水平较治疗前升高[(31.51±3.87)vs(27.60±3.58)ng/ml,P<0.05],UAlb/Cr降低[(88.50±8.90)vs(116.20±10.30)mg/24h,P<0.01]。治疗后GLI亚组UAlb/Cr较治疗前降低[(99.70±12.80)vs(122.40±13.10)mg/24h,P<0.05],血清ANGPTL4水平变化比较差异无统计学意义[(27.20±3.54)vs(26.60±3.48)ng/ml,P>0.05]。多元线性回归分析显示,HbA1c、FIns、UAlb/Cr是血清ANGPTL4水平的独立影响因素。结论 CKD患者血清ANGPTL4水平降低,吡格列酮通过增加血清ANGPTL4水平对CKD患者发挥治疗作用。