Diagnostic Performance of Serum Asialo α1-Acid Glycoprotein Levels to Predict Liver Cirrhosis

Secreted Glycoproteins That Regulate Synaptic Function: the Dispatchers in the Central Nervous System

Glycoproteins are proteins that contain oligosaccharide chains. As widely distributed functional proteins in the body, glycoproteins are essential for cellular development, cellular function maintenance, and intercellular communication. Glycoproteins not only play a role in the cell and the membrane, but they are also secreted in the intercell. These secreted glycoproteins are critical to the central nervous system for neurodevelopment and synaptic transmission. More specifically, secreted glycoproteins play indispensable roles in neurite growth mediation, axon guiding, synaptogenesis, neuronal differentiation, the release of synaptic vesicles, subunit composition of neurotransmitter receptors, and neurotransmitter receptor trafficking among other things. Abnormal expressions of secreted glycoproteins in the central nervous system are associated with abnormal neuron development, impaired synaptic organization/transmission, and neuropsychiatric disorders. This article reviews the secreted glycoproteins that regulate neuronal development and synaptic function in the central nervous system, and the molecular mechanism of these regulations, providing reference for research about synaptic function regulation and related central nervous system diseases.

Diagnostic Efficacy of Serum Asialo α1-Acid Glycoprotein Levels for Advanced Liver Fibrosis and Cirrhosis in Patients with Chronic Hepatitis B Compared to That in Healthy Subjects: A Prospective Study

Background: Serum asialo α1-acid gycoprotein (AsAGP) is a novel biomarker specific to liver fibrosis. Aim: To evaluate the diagnostic efficacy of serum AsAGP levels in classifying the severity of liver fibrosis and differentiating liver cirrhosis (LC) in patients with chronic hepatitis B (CHB) from healthy controls. Methods: Overall, 206 subjects were prospectively enrolled. LC was diagnosed based on liver stiffness levels (>11 kPa) measured using transient elastography. Serum AsAGP levels were measured using an antibody-lectin sandwich immunoassay. We investigated the diagnostic performance by comparing serum AsAGP levels among healthy control, CHB, and CHB with LC groups. Sensitivity, specificity, and optimal AsAGP cut-off values were also calculated. Results: Serum AsAGP levels were significantly different between healthy controls, CHB patients, and CHB patients with LC (1.04 ± 0.31 µg/mL, 1.12 ± 0.34 µg/mL, 1.51 ± 0.43 µg/mL respectively; p < 0.001). Serum AsAGP levels positively correlated with liver stiffness (r = 0.46, p < 0.001). AUROC of healthy control versus CHB with LC was 0.821 (p < 0.001, optimal cut-off 1.036 µg/mL). AUROC of healthy control versus CHB was 0.624 (p = 0.049, optimal cut-off level 0.934 µg/mL). AUROC of CHB versus CHB with LC was 0.765, (p < 0.001, optimal cut-off 1.260 µg/mL). Conclusions: Serum AsAGP levels in CHB patients with LC were significantly higher than those in healthy controls and CHB patients. AsAGP levels showed good diagnostic performance in predicting advanced fibrosis and cirrhosis, which suggests a potential role as a biomarker for predicting the progression of liver disease in CHB.

Orosomucoid in liver diseases

In this editorial, the roles of orosomucoid (ORM) in the diagnoses and follow-up assessments of both nonneoplastic diseases and liver tumors are discussed with respect to the publication by Zhu et al presented in the previous issue of World Journal of Gastroenterology (2020; 26(8): 840-817). ORM, or alpha-1 acid glycoprotein (AGP), is an acute-phase protein that constitutes 1% to 3% of plasma proteins in humans and is mainly synthesized in the liver. ORM exists in serum as two variants: ORM1 and ORM2. Although the variants share 89.6% sequence identity and have similar biological properties, ORM1 constitutes the main component of serum ORM. An interesting feature of ORM is that its biological effects differ according to variations in glycosylation patterns. This variable feature makes ORM an attractive target for diagnosing and monitoring many diseases, including those of the liver. Recent findings suggest that a sharp decrease in ORM level is an important marker for HBV-associated acute liver failure (ALF), and ORM1 plays an important role in liver regeneration. In viral hepatitis, increases in both ORM and its fucosylated forms and the correlation of these increases with fibrosis progression suggest that this glycoprotein can be used with other markers as a noninvasive method in the follow-up assessment of diseases. In addition, similar findings regarding the level of the asialylated form of ORM, called asialo-AGP (AsAGP), have been reported in a follow-up assessment of fibrosis in chronic liver disease. An increase in ORM in serum has also been shown to improve hepatocellular carcinoma (HCC) diagnosis performance when combined with other markers. In addition, determination of the ORM level has been useful in the diagnosis of HCC with AFP concentrations less than 500 ng/mL. For monitoring patients with AFP-negative HCC, a unique trifucosylated tetra-antennary glycan of ORM may also be used as a new potential marker. The fact that there are very few studies investigating the expression of this glycoprotein and its variants in liver tissues constitutes a potential limitation, especially in terms of revealing all the effects of ORM on carcinogenesis and tumor behavior. Current findings indicate that ORM2 expression is decreased in tumors, and this is related to the aggressive course of the disease. Parallel to this finding, in HCC cell lines, ORM2 decreases HCC cell migration and invasion, supporting reports of its tumor suppressor role. In conclusion, the levels of ORM and its different glycosylated variants are promising additional biomarkers for identifying ALF, for monitoring fibrosis in viral hepatitis, and for diagnosing early HCC. Although there is evidence that the loss of ORM2 expression in HCC is associated with poor prognosis, further studies are needed to support these findings. Additionally, investigations of ORM expression in borderline dysplastic nodules and hepatocellular adenomas, which pose diagnostic problems in the differential diagnosis of HCC, especially in biopsy samples, may shed light on whether ORM can be used in histopathological differential diagnosis.

Clinical implications of serum Mac-2-binding protein glycan isomer as a novel biomarker of advanced hepatic fibrosis in diabetes

Background

Appropriate strategy for screening, identification, and linkage to care of patients with advanced fibrosis in the general population is a current issue. The aim of this study was to find reference values and the clinical role of Mac-2 binding protein glycan isomer (M2BPGi) in a health check-up setting.

Methods

This study was designed as cross-sectional study. Adult subjects (n=1,073) who underwent a health check-up were included in the final analysis, and 952 subjects with risk factors for liver disease and insufficient data were excluded. M2BPGi quantification was based on a lectin antibody sandwich immunoassay. Fatty liver was diagnosed using abdominal sonography.

Results

The reference value of M2BPGi was 0.5–1.0 cut off index (COI) in the average risk group. Serum M2BPGi showed a positive correlation with metabolic parameters as well as age. Prevalence of abnormal M2BPGi (>1.0) was higher in low muscle mass (4.7%, vs. 17.4%, P=0.002), metabolic syndrome (14.2% vs. 30.4%, P=0.003), and hypertension (21.8%, vs. 58.7%, P<0.001) compared to healthy controls. M2BPGi was positively correlated with estimated fibrosis values such as FIB-4 (R=0.293, P<0.001) and NAFLD fibrosis score (R=0.248, P<0.001). Although the prevalence of advanced fibrosis in the total population was just 1.6% (FIB-4 >2.65), the prevalence of advanced fibrosis increased to 50% in the high M2BPGi (>1.0) group with diabetes. This value was 31.25 times higher than in the total population group.

Conclusions

The results indicated a high possibility of advanced hepatic fibrosis in diabetic subjects with abnormal M2BPGi level (>1.0).