Objective:To compare the expression level of exosomal miR-503 in peritoneal dialysis effluent (PDE) from patients of different peritoneal transport characteristics, predict the target genes of miR-503 and provide bioinformatic data for researches of peritoneal transport characteristics.Methods:Twenty-four stable peritoneal dialysis (PD) patients were selected and divided into high transport group (H group, n=12) and low transport group (L group, n=12) according to the results of peritoneal equilibration tests (PET). The 500 ml PDE that was left on the patient's abdomen overnight was collected and concentrated using ultrafiltration cell. Exosomes in PDE were resuspended in phosphate buffered saline (PBS) after ultracentrifugation and the characteristics of PDE exosomes were identified by transmission electron microscope (TEM), nanoparticle tracking analysis (NTA), Western blotting and fluorescent staining. MicroRNAs were extracted from PDE exosomes. The expression levels of PDE exosomal miR-503 in the two groups were detected by quantitative real-time PCR. Then the relations between the relative quantity of PDE exosomal miR-503 and PET values or 24 h ultrafiltration volume (UF) were analyzed. Targetscan and miRDB databases were used to predict the target genes of miR-503. Gene ontology (GO) functional enrichment and Kyoto encyclopedia of genes and genomes (KEGG) signaling pathway analysis were relied on DAVID (https://david.ncifcrf.gov/). Results:The exosomes in PDE showed a round and cup-shaped morphology under TEM, and the diameters were approximately 100 nm measured by NTA. The specific biomarkers of exosomes, CD63, CD81 and heat shock protein -70 (HSP-70) were all detected by Western blotting. The internalization and uptake of the exosomes was observed after fluorescent staining. The relative expression level of PDE exosomal miR-503 in H group was found to be significantly higher than that in L group ( P=0.002), and the relative quantity of PDE exosomal miR-503 was significantly positively correlated with PET values ( r=0.547, P=0.006), but not 24 h UF ( r=-0.297, P=0.159). There were 156 target genes of miR-503 in total that could be predicted by two different databases at the same time. GO analysis of these 156 target genes was mainly focused on kinase binding, regulation of protein modification and catabolic process as well as regulation of epithelial cell proliferation. KEGG enriched many tumor associated or classical signaling pathways, including transforming growth factor-β (TGF-β) signaling pathway and vascular endothelial growth factor (VEGF) signaling pathway. The prediction showed that vascular endothelial growth factor A (VEGFA) was a direct target gene of miR-503 and it was also related to many proteins involved in fibrosis mechanism. Conclusions:The expression level of PDE exosomal miR-503 is significantly higher in H group, and positively correlates with PET values, which may regulate the angiogenesis of peritoneal vessels by targeting VEGFA.

Objective·To explore the efficacy and safety of compound amino acid capsules in the treatment of malnutrition and calcium and phosphorus metabolism disorders in maintenance hemodialysis patients.Methods·In this prospective,randomized,controlled,single-center study,forty maintenance hemodialysis patients from Renji Hospital,Shanghai Jiao Tong University School of Medicine were randomly divided into two groups,the treatment group(n=21)and the control group(n=19).The treatment group was given oral compound amino acid capsules on the basis of regular hemodialysis treatment,while the control group received no special nutritional intervention.Serum albumin,prealbumin,hemoglobin,ferritin,calcium,phosphorus,1,25-(OH)2-D3 and intact parathyroid hormone levels were analyzed every 3 months,and the incidence of adverse events including death,cardio-cerebrovascular accidents and vascular access failure was recorded.The total follow-up period was 9 months.Results·Serum albumin and prealbumin in the treatment group at 6-month and 9-month were significantly higher than the baseline parameters(albumin,t=3.574,5.599,both P<0.05;prealbumin,t/Z=-2.485,2.921,both P<0.05).Albumin in the control group increased at 9-month with a lower amplification compared to the treatment group(t=3.877,P=0.001),while the difference of prealbumin showed no statistical significance during follow-up.Hemoglobin and serum ferritin in the treatment group started to increase at 3-month(hemoglobin,t=2.192;ferritin,t=2.994;both P<0.05).Phosphorus in treatment group decreased at 3-month and 9-month(t/Z=-2.743,-2.103,both P<0.05),while phosphorus in the control group remained relatively stable during the first 6 months and increased at 9-month(Z=-2.178,P=0.029).Calcium and 1,25-(OH)2-D3 in the treatment group at 3-month and 6-month were significantly higher than the baseline parameters(calcium,t=4.581,4.922,both P=0.000;1,25-(OH)2-D3 t/Z=4.504,-2.374,both P<0.05),while the increase in blood calcium in the control group was significantly smaller than that in the treatment group during the same period.1,25-(OH)2-D3 in the control group showed no significant improvement.There was no significant difference in intact parathyroid hormone level,incidence of adverse events and other laboratory examination results between the two groups.Conclusion·Compound amino acid capsules can ameliorate the nutrition status and regulate calcium and phosphorus metabolism effectively and safely in maintenance hemodialysis patients.