Effect of different intravenous iron preparations on lymphocyte intracellular reactive oxygen species generation and subpopulation survival

<p>Abstract</p> <p>Background</p> <p>Infections in hemodialysis (HD) patients lead to high morbidity and mortality rates and are associated with early cardiovascular mortality, possibly related to chronic inflammation. Intravenous (IV) iron is widely administered to HD patients and has been associated with increased oxidative stress and dysfunctional cellular immunity. The purpose of this study was to examine the effect of three commercially available IV iron preparations on intracellular reactive oxygen species generation and lymphocyte subpopulation survival.</p> <p>Methods</p> <p>Peripheral blood mononuclear cells (PBMC) were isolated from healthy donor buffy coat. PBMC were cultured and incubated with 100 μg/mL of sodium ferric gluconate (SFG), iron sucrose (IS) or iron dextran (ID) for 24 hours. Cells were then probed for reactive oxygen species (ROS) with dichlorofluorescein-diacetate. In separate studies, isolated PBMCs were incubated with the 25, 50 or 100 μg/mL iron concentrations for 72 hours and then stained with fluorescein conjugated monoclonal antibodies for lymphocyte subpopulation identification. Untreated PBMCs at 24 hours and 72 hours served as controls for each experiment.</p> <p>Results</p> <p>All three IV iron preparations induced time dependent increases in intracellular ROS with SFG and IS having a greater maximal effect than ID. The CD4+ lymphocytes were most affected by IV iron exposure, with statistically significant reduction in survival after incubation with all three doses (10, 25 and 100 μg/mL) of SFG, IS and ID.</p> <p>Conclusion</p> <p>These data indicate IV iron products induce differential deleterious effects on CD4+ and CD16+ human lymphocytes cell populations that may be mediated by intracellular reactive oxygen species generation. Further studies are warranted to determine the potential clinical relevance of these findings.</p

Comparison of two different strategies for human monocyte subsets gating within the large-scale prospective CARE FOR HOMe Study.

Monocytes are heterogeneous cells consisting of (at least) three subsets: classical, intermediate, and nonclassical monocytes. Correct enumeration of cell counts necessitates well-defined gating strategies, which are essentially based upon CD14 and CD16 expression. For the delineation of intermediate from nonclassical monocytes, a &quot;rectangular gating (RG) strategy&quot; and a &quot;trapezoid gating (TG) strategy&quot; have been proposed. We compared the two gating strategies in a well-defined clinical cohort of patients with chronic kidney disease (CKD). Within the ongoing CARE FOR HOMe study, monocyte subsets were reanalyzed in 416 CKD patients, who were followed 3.6&thinsp;&plusmn;&thinsp;1.6 years for the occurrence of a cardiovascular event. Gating was performed by either RG or TG. We analyzed the expression of surface markers, and compared the predictive role of cell counts of monocyte subsets, as defined by RG and TG, respectively. With both gating strategies, higher intermediate monocyte counts predicted the cardiovascular endpoint in Kaplan-Meier analyses (P&thinsp;&lt;&thinsp;0.001 with RG; P&thinsp;&lt;&thinsp;0.001 with TG). After correction for confounders, intermediate monocyte counts remained independent predictors in Cox-Regression analyses (HR&thinsp;=&thinsp;1.013 [95% CI: 1.006-1.020; P&thinsp;&lt;&thinsp;0.001] with RG; HR&thinsp;=&thinsp;1.015 [95% CI: 1.006-1.024; P&thinsp;=&thinsp;0.001] with TG). NRI was 3.9% when reclassifying patients from quartiles of intermediate monocyte counts with RG strategy toward quartiles of intermediate monocytes counts with TG strategy. In expression analysis, those monocytes which are defined as intermediate monocytes by the RG strategy and as nonclassical monocytes by the TG strategy share characteristics of both subsets. In conclusion, intermediate monocytes were independent predictors of cardiovascular outcome irrespective of the applied gating strategy. Future studies should aim to identify markers that allow for an unequivocal definition of intermediate monocytes, which may further improve their power to predict cardiovascular events

Supplementary Material for: Best Albuminuria Measurement to Predict Cardiovascular and Renal Events

<b><i>Background:</i></b> Kidney Disease Improving Global Outcomes (KDIGO) guidelines encourage clinicians to estimate 24-hour albuminuria as albumin to creatinine ratio (ACR) from spot urine samples. However, ACR underestimates 24-hour albumin excretion in muscular individuals. Equations that adjust ACR for surrogates of muscle mass to yield an estimated albumin excretion rate (eAER) were developed. We hypothesised that eAER is a better predictor of cardiovascular and renal outcomes than ACR. <b><i>Methods:</i></b> We determined ACR and eAER among 443 patients with chronic kidney disease G2-G4 recruited into the CARE FOR HOMe study. Patients were classified into KDIGO albuminuria categories, and followed for cardiovascular and renal events. The primary analysis was the net reclassification improvement (NRI) for those with and without events within 3 years of follow-up. <b><i>Results:</i></b> Eighty five patients experienced cardiovascular events during 3 years of follow-up, 13 of whom were reclassified to a more advanced albuminuria category, and 1 patient to a less advanced category by eAER compared to ACR (NRI_event: 14.1% (95% CI 5.8-22.4)). Among 358 patients without a cardiovascular event, 17 patients were reclassified to a more advanced albuminuria category, and 2 patients to a less advanced category by eAER (NRI_{no event}: -4.2%, 95% CI -8.5 to -1.8). Sixty patients went through renal events, and 383 patients had event-free 3-year follow-up. NRI_event was 6.7% (95% CI -1.2 to 14.5), and NRI_{no event} was -6.0% (95% CI -10.6 to 3.4) for renal events. <b><i>Conclusion:</i></b> Compared to ACR albuminuria categories, eAER categories are better associated with future cardiovascular events, but not with renal events