Serum retinol binding protein 4 and clinical outcome in postoperative biliary atresia

Low expression of RBP4 in the vitreous humour of patients with proliferative diabetic retinopathy who underwent Conbercept intravitreal injection

Intravitreal injection of anti-VEGF antibodies has been widely used in the treatment of proliferative diabetic retinopathy (PDR). However, anti-VEGF drugs can exacerbate fibrosis and eventually lead to retinal detachment. To explore proteins closely related to fibrosis, we conducted proteomic analysis of human vitreous humour collected from PDR patients who have or have not intravitreal Conbercept (IVC) injection. Sixteen vitreous humour samples from PDR patients with preoperative IVC and 20 samples from those without preoperative IVC were examined. An immunodepletion kit was used to remove high-abundance vitreous proteins. Conbercept-induced changes were determined using a tandem mass tag-based quantitative proteomic strategy. Enzyme-linked immunosorbent assays were performed to confirm the concentrations of selected proteins and validate the proteomic results. Based on a false discovery rate between 0.05% and -0.05% and a fold-change > 1.5, 97 proteins were altered (49 higher levels and 48 lower levels) in response to IVC. Differentially expressed proteins were found in the extracellular and intracellular regions and were found to be involved in VEGF binding and VEGF-activated receptor activity. Protein-protein interactions indicated associations with fibrosis, neovascularisation and inflammatory signalling pathways. We found the low levels of RBP4 in the vitreous humour of PDR patients with IVC injection, as revealed by ELISA and proteomic profiling. Moreover, RBP4 significantly restored the mitochondrial function of HRMECs induced by AGEs and down regulated the level of glycolysis. Our study is the first to report that RBP4 decreases in the vitreous humour of PDR patients who underwent Conbercept treatment, thereby verifying the role of RBP4 in glucose metabolism. Results provide evidence for the potential mechanism underlying Conbercept-related fibrosis.

Optimised expression and purification of RBP4 and preparation of anti-RBP4 monoclonal antibody

The expression level of retinol-binding protein 4 (RBP4) protein is closely related to liver damage and plays an important role in the diagnosis and prognosis of cancer. However, the preparation of anti-RBP4 mAb or exploration on the application of anti-RBP4 mAb has not been reported thus far. In the present study, we constructed a pET30a-RBP4 recombinant vector, used E. coli BL21 (DE3) as the vector to express the RBP4 recombinant protein and prepared anti-RBP4 mAb using hybridoma technology. We performed immunohistochemical analysis on hepatocellular carcinoma (HCC) and adjacent tissues by using this anti-RBP4 mAb. In addition to the high-purity RBP4 recombinant protein, we successfully developed the anti-RBP4 mAb with high affinity and specificity; it binds to natural RBP4 protein and is suitable for immunohistochemical analysis.

Biomarkers for the diagnosis and post-Kasai portoenterostomy prognosis of biliary atresia: a systematic review and meta-analysis

To evaluate the accuracy of biomarkers for the early diagnosis of biliary atresia (BA) and prognostic stratification after Kasai portoenterostomy (KPE). We conducted a systematic review of PubMed, Web of Science, Embase, Scopus and OVID for English literature reporting BA biomarkers published before August 2020. Screening, data extraction, and quality assessment were performed in duplicate. A total of 51 eligible studies were included in the systematic review, and data from 12 (4182 subjects) were extracted for meta-analysis regarding the following 2 domains: (1) serum matrix metallopeptidase-7 (MMP-7), interleukin33 (IL-33) and γ-glutamyl transferase (GGT) to differentiate BA from non-BA; (2) the aspartate aminotransferase to platelet ratio index (APRi) to predict post-KPE liver fibrosis/cirrhosis. The summary sensitivity, specificity and area under the curve (AUC) of MMP-7 for diagnosing BA were 96%, 91% and 0.9847, respectively, and those of GGT were 80%, 79% and 0.9645, respectively. The summary sensitivity and specificity of IL-33 for diagnosing BA were 77% and 85%, respectively. The summary sensitivity and specificity of APRi for predicting post-KPE liver fibrosis were 61% and 80%, respectively, and the summary sensitivity, specificity and AUC of APRi for predicting post-KPE cirrhosis were 78%, 83% and 0.8729, respectively. Moreover, good evidence was shown in investigations of serum IL-18 and IL-33 in distinguishing BA from healthy controls, serum IL-18 for prognosis of post-KPE persistent jaundice, and serum hyaluronic acid and MMP-7 for prognosis of post-KPE significant liver fibrosis. MMP-7, IL-33 and GGT are useful biomarkers to assist in the diagnosis of BA. APRi might be used to predict post-KPE significant liver fibrosis and cirrhosis. These noninvasive biomarkers can be integrated into the management protocol of BA.

Expression of fibroblast growth factor 21 in patients with biliary atresia

Fibroblast growth factor 21 is a critical circulating adipokine involving in metabolic disorders and various liver diseases. This study was performed to investigate whether FGF21 is also associated with the pathophysiology of biliary atresia. Serum FGF21 levels were measured in 57 BA patients and 20 age matched healthy controls. We also examined hepatic FGF21 mRNA expression and FGF21 protein levels in liver tissues obtained from 15 BA patients undergoing liver transplantation and 5 cases of pediatric donation after cardiac death donor without liver diseases by RT-PCR and Western blotting. Patients with BA showed significantly higher serum FGF21 levels than those without BA (554.7pg/mL [83-2300] vs. 124.5pg/mL [66-270], P<0.05). Patients with BA also had significantly higher FGF21 mRNA and protein levels in hepatic tissues than control subjects. Serum FGF21 expression increased corresponding to the severity of liver fibrosis. Furthermore, serum FGF21 levels dropped significantly in BA patients within 6months after liver transplantation and approached baseline in healthy controls (P>0.05). In vivo, FXR knockout could significantly abrogate cholestasis induced FGF21 expression. FGF21 levels in serum and liver tissue increased significantly in BA patients. In vivo, cholestasis could induce FGF21 expression in FXR dependent manner.

Soluble receptor for advanced glycation end products and liver stiffness in postoperative biliary atresia

OBJECTIVES

Soluble receptor for advanced glycation end products (sRAGE) has emerged as a possible biomarker of several disease conditions, including liver injury. This study was aimed to assess serum sRAGE and liver stiffness in biliary atresia (BA).

DESIGN AND METHODS

Forty postoperative BA patients and 20 controls were enrolled. Serum sRAGE levels were analyzed by enzyme-linked immunosorbent assay. Liver stiffness scores were measured by transient elastography.

RESULTS

BA patients had higher serum sRAGE and liver stiffness values than controls (P<0.001). Serum sRAGE and liver stiffness values were significantly elevated in BA patients with jaundice compared to those without jaundice (P<0.001). Additionally, serum sRAGE was correlated with liver stiffness and serum total bilirubin (r=0.65, P<0.001 and r=0.71, P<0.001, respectively).

CONCLUSION

Serum sRAGE was associated with the severity of BA. Accordingly, serum sRAGE and liver stiffness may serve as indicators reflecting the severity and the development of hepatic fibrosis in postoperative BA.