Circulating miRNA 122-5p Expression Predicts Mortality and Cardiovascular Events in Chronic Hemodialysis Patients: A Multicentric, Pilot, Prospective Study.

BACKGROUND: Despite patients undergoing chronic hemodialysis (HD) being notoriously prone to adverse cardiovascular (CV) events, risk prediction in this population remains challenging. miRNA 122-5p, a short, non-coding RNA predominantly involved in lipid and carbohydrate metabolism, has recently been related to the onset and progression of CV disease. METHODS: We run a pilot, multicenter, longitudinal, observational study to evaluate the clinical significance and prognostic usefulness of circulating miRNA 122-5p in a multicentric cohort of 74 individuals on maintenance HD. RESULTS: Patients displayed lower circulating miRNA 122-5p as compared to healthy controls (p = 0.004). At correlation analyses, ALT (ß = 0.333; p = 0.02), E/e' (ß = 0.265; p = 0.02) and CRP (ß = -0.219; p = 0.041) were independent predictors of miRNA 122-5p levels. During a median follow-up of 22 months (range of 1-24), 30 subjects (40.5%) experienced a composite endpoint of all-cause mortality and fatal/non-fatal CV events. Baseline circulating miRNA 122-5p was higher in these subjects (p = 0.01) and it predicted a significantly higher risk of endpoint occurrence (Kaplan-Meier crude HR 3.192; 95% CI 1.529-6.663; p = 0.002; Cox regression adjusted HR 1.115; 95% CI 1.009-1.232; p = 0.03). CONCLUSIONS: Altered miRNA 122-5p levels in HD patients may reflect hepatic and CV damage and may impart important prognostic information for improving CV risk prediction in this particular setting.

A small circulating miRNAs signature predicts mortality and adverse cardiovascular outcomes in chronic hemodialysis patients.

Background: Chronic hemodialysis (HD) patients exhibit severe morpho-functional cardiac alterations, putting them at a high risk of death and adverse cardiovascular (CV) outcomes. Despite the fact that an unbalanced expression of various microRNAs (miRNAs) has been related to pathological cardiac remodeling and worse CV outcomes, scarce evidence exists on their role in this setting. Methods: We evaluated circulating levels of a selected miRNAs panel (30a-5p, 23a-3p, 451a and let7d-5p) in 74 chronic HD patients together with a thorough clinical and echocardiography assessment. Individuals were then prospectively followed (median 22 months). The primary endpoint was a composite of all-cause and CV mortality and non-fatal CV events. Results: Circulating levels of all miRNAs were lower in HD patients as compared with healthy controls and independently correlated to the severity of cardiac dysfunction. miRNA 30a-5p, 23a-3p and 451a expression was even lower in 30 subjects (40.5%) reaching the composite endpoint (P < .001), while no differences were reported for let7d-5p. The predictive value of these miRNAs was supported by univariate followed by multivariate Cox regression analyses [hazard ratio (HR) ranging from 0.943 to 0.995; P = .05 to .02] while Kaplan-Meier analyses confirmed a faster progression to the endpoint in individuals displaying miRNA levels below an optimal receiver operating characteristic-derived cut-off value (P ranging from .001 to <.0001; crude HRs 7.95 to 8.61). Conclusions: Lower circulating levels of miRNA 30-5p, 23a-3p and 451a in HD patients may reflect cardiac abnormalities and predict a higher risk of worse clinical outcomes in the short mid-term. Future studies on larger HD populations are needed to generalize these findings.

Circulating Omentin-1 levels and altered iron balance in chronic haemodialysis patients.

BACKGROUND: Iron deficiency is highly prevalent among patients undergoing chronic haemodialysis (HD) but its correct identification is often problematic as common biomarkers of iron status, such as transferrin saturation (TSAT) and ferritin, can be altered by inflammation or malnutrition. METHODS: In this pilot multicentre study, we aimed at evaluating circulating levels of Omentin-1, a novel fat depot-specific adipokine that is also involved in iron regulation, in a cohort of 85 chronic HD patients with relation to their iron status. RESULTS: Omentin-1 levels in HD were statistically higher than in healthy controls (P = 0.03) and there was a significant, growing trend in all iron parameters across Omentin-1 tertiles (P < 0.001). Compared with patients with optimal iron status, Omentin-1 levels were lower in subjects categorized according to TSAT ≤20% or serum ferritin ≤200 µg/L (both P < 0.001) and even more reduced in 19 patients (22%) simultaneously displaying low levels of both markers (P < 0.001). In this latter group, Omentin-1 levels increased in parallel to all other iron markers after iron correction by i.v. supplementation. At multivariate regression analyses, ferritin (ß = 0.71; P < 0.001) and TSAT (ß = 0.32; P = 0.03) remained the sole independent predictors of Omentin-1 levels. This biomarker also showed a remarkable diagnostic capacity at receiver operating characteristic analyses in identifying iron-depleted HD patients according to a criterion of TSAT ≤20% [area under the curve (AUC) 0.827], ferritin ≤200 µg/L (AUC 0.863) or low levels of both parameters (AUC 0.907). CONCLUSIONS: Findings obtained indicate that Omentin-1 is somewhat involved in iron balance regulation and might be a candidate biomarker for diagnosing and managing altered iron conditions in HD patients.