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Vascular calcification (VC) is an independent risk factor for cardiovascular mortality in end-stage renal disease (ESRD) patients. The pathogenesis of VC is complicated and unclear. Uremic toxins produced by gut microbiota can promote VC. This study aims to identify the differences in gut microbiota between the different VC groups and the main bacteria associated with VC in hemodialysis (HD) patients in an attempt to open up new preventive and therapeutic approaches and define the probable mechanism for VC in HD patients in the future. A total of 73 maintenance HD patients were enrolled in this cross-sectional study. According to the abdominal aortic calcification (AAC) scores, the participants were divided into the high AAC score group and the low AAC score group. High-throughput sequencing of the gut microbiota was performed and the results were evaluated by alpha diversity, beta diversity, species correlation, and model predictive analyses. The prevalence of VC was 54.79% (40/73) in the study. The majority of phyla in the two groups were the same, including Firmicutes, Actinobacteriota, Proteobacteria, and Bacteroidota. The microbial diversity in the high AAC score group had a decreasing trend (p = 0.050), and the species abundance was significantly lower (p = 0.044) than that in the low AAC score group. The HD patients with high AAC scores showed an increased abundance of Proteobacteria and decreased abundances of Bacteroidota and Synergistota at the phylum level; increased abundances of Escherichia-Shigella, Ruminococcus_gnavus_group, and Lactobacillus; and decreased abundances of Ruminococcus and Lachnospiraceae_NK4A136_group at the genus level (p<0.05). Escherichia-Shigella and Ruminococcus_gnavus_group were positively correlated with VC, and Ruminococcus, Adlercreutzia, Alistipes, and norank_f__Ruminococcaceae were negatively correlated with VC. Escherichia-Shigella had the greatest influence on VC in HD patients, followed by Ruminococcus and Butyricimonas. Our results provide clinical evidence that there was a difference in gut microbiota between the different VC groups in HD patients. Escherichia–Shigella, a lipopolysaccharide (LPS)-producing bacterium, was positively correlated with VC and had the greatest influence on VC. Ruminococcus, a short-chain fatty acid (SCFA)-producing bacterium, was negatively correlated with VC and had the second strongest influence on VC in HD patients. The underlying mechanism is worth studying. These findings hint at a new therapeutic target. [ABSTRACT FROM AUTHOR]

Background/Aims: Vascular calcification, which involves an active cellular transformation of vascular smooth muscle cells into bone forming cells, is prevalent and predicts mortality in dialysis patients. Its mechanisms are complex and unclear. We presume that irisin, a newly identified myokine also may play roles in vascular calcification in hemodialysis patients. This study aims to evaluate serum irisin levels and establish their relation to vascular calcification and other parameters in hemodialysis patients. Methods: A total of 150 patients on maintenance hemodialysis treatment and 38 age- and sex-matched healthy controls were enrolled in this cross-sectional study. Serum irisin concentrations were measured by ELISA. Vascular calcification was evaluated by abdominal aortic calcification scores. Results:Serum irisin concentrations were significantly lower in hemodialysis patients than in controls [52.8 (22.0, 100.0) vs. 460.8 (434.8, 483.4) ng/ml, P<0.01]. In addition, irisin was negatively correlated with the parathyroid hormone level (P=0.01). The HD patients with vascular calcification showed significantly lower serum irisin concentrations [39.0 (21.7, 86.2) vs.79.0 (39.5, 130.2) ng/mL, P<0.01]. Compared with the group without vascular calcification multivariate logistic regression analyses revealed that serum irisin, HD vintage and age were significant independent determinant factors for vascular calcification in HD patients. Conclusion: Our results are the first to provide a clinical evidence of the association between serum irisin and vascular calcification in HD patients. Lower irisin levels, long-term hemodialysis and old ages are independent risk factors in HD patients. [ABSTRACT FROM AUTHOR]

Background: With lipid level being a major contributing factor for cardiovascular health, the high cardiovascular mortality among dialysis patients has raised substantial concerns in regard to the optimal lipid level in these patient population. Objective: To explore the optimal lipid level for the survival of dialysis patients. Methods: The lipid profile was measured for each patient. All participants were followed throughout the course of the study. Cox proportional hazards analysis was performed to analyze the prognostic value of lipid level on the survival of these patients. Results: In our study that included 311 stable maintenance dialysis patients, 54.98% of the participants had LDL-C level ≥100 mg/dl and 82.91% of the patients with triglycerides ≥200 mg/dl had non-HDL level ≥130 mg/dl. During the follow-up period of 48.0 (18.0, 55.5) months, 149 (47.91%) participants died. Among those who died, 59 patients died of cardiovascular disease (CVD) and 33 patients died of ischemic CVD (12.0, 4.7, and 2.7 events per 100 patient-years, respectively). Patients with LDL-C 100–130 mg/dl or non-HDL 130–160 mg/dl had a lower all-cause mortality rate than those who did not meet these criteria. After adjusting for the traditional and ESRD-related risk factors, non-HDL was found to be the independent risk factor for the all-cause mortality. Compared to those patients with non-HDL 130–160 mg/dl, patients with non-HDL <100 mg/dl, 100–130 mg/dl, 160–190 mg/dl, or ≥190 mg/dl all had higher all-cause mortality: HR (95% CI) 3.207 (1.801, 5.713), 2.493 (1.485, 4.184), 2.476 (1.423, 4.307), and 1.917 (1.099, 3.345), respectively. There were no differences in nutrition, comorbidity, and inflammation indices among the patients with different non-HDL groups. However, patients with non-HDL of 130–160 mg/dl had the lowest corrected calcium and calcium phosphate product values as compared with other non-HDL groups. Conclusion: Our study demonstrated that non-HDL 130–160 mg/dl might be the most appropriate lipid level in our dialysis patients. Our follow-up data also showed that patients with higher lipid level had poorer prognosis, just as in the general population. [ABSTRACT FROM AUTHOR]