Iron increases the profibrotic properties of the senescent peritoneal mesothelial cells

BACKGROUND

Treatment of anemia in peritoneal dialysis patients often requires intravenous iron supplementation. Iron diffuses into the peritoneal cavity and is injurious to the peritoneum. We studied how intermittent exposure to iron changes the properties of the senescent peritoneal mesothelial cells (MC).

METHODS

Replicative senescence was induced in MC in control medium (Con) or in control medium with intermittent exposure to iron isomaltoside 15 µg/dL (Con-IIS). After 10 passages properties of MC from both groups were compared to MC not exposed to replicative senescence.

RESULTS

In senescent MC population doubling time was elongated, intracellular generation of free radicals and staining for β-galactosidase was stronger than in MC not exposed to replicative senescence. All these effects were stronger in MC intermittently exposed to IIS. In these cells intracellular iron content was also higher. Also expression of genes p21 and p53 was stronger in MC intermittently treated with IIS. In senescent cells higher release and expression of IL6 and TGFβ1 was observed and that effect was stronger in MC treated with iron. Senescent MC had reduced fibrinolytic activity, what may predispose to the peritoneal fibrosis. Synthesis of collagen was higher in senescent cells, more in MC treated with iron.

CONCLUSION

MC aging results in change of their genotype and phenotype which lead to their profibrotic effect. Exposure to iron enhances these changes.

Novel iron-containing phosphate binders and anemia treatment in CKD: oral iron intake revisited

Recent reports have shown that novel phosphate binders containing iron are not only efficacious for the treatment of hyperphosphatemia but also may reduce the need for erythropoiesis-stimulating agents and intravenous (IV) iron for anemia management in patients on maintenance hemodialysis (MHD). Possible healthcare cost savings, which have not been demonstrated in a long-term study, may be an additional advantage of using such multi-pronged treatment strategies for the control of both hyperphosphatemia and iron needs. It is currently assumed that oral iron supplementation is less efficient than the IV route in patients with chronic kidney disease (CKD). The unexpected efficacy of novel iron-containing phosphate binders, such as ferric citrate, in repleting insufficient iron stores and improving the anemia of CKD could change this view. Previous assumptions of self-controlled iron uptake by 'mucosal block' or hepcidin, or else by impaired intestinal iron absorption due to CKD-associated inflammation cannot be reconciled with recent observations of the effects of ferric citrate administration. Citrate in the intestinal lumen may partly contribute to the acceleration of iron absorption. Animal experiments and clinical studies have also shown that oral iron overload can cause excessive iron accumulation despite high hepcidin levels, which are not able to block iron absorption completely. However, like with IV iron agents, no long-term safety data exist with respect to the effects of iron-containing phosphate binders on 'hard' patient outcomes. Future randomized prospective studies in patients with CKD are necessary to establish the safety of oral iron-containing phosphate binders for the control of both hyperphosphatemia and renal anemia.

Anaemia management in non-dialysis chronic kidney disease (CKD) patients: a multicentre prospective study in renal clinics

BACKGROUND

Knowledge on anaemia management in non-dialysis chronic kidney disease (ND-CKD) patients regularly followed in renal clinics is scarce although being essential to identifying areas of therapeutic improvement.

METHODS

We prospectively evaluated anaemia management in two visits, performed 6 months apart, in 755 prevalent ND-CKD stage 3b-5 patients followed in 19 nephrology clinics from ≥6 months. Anaemia was defined as severe (Hb <11 g/dL) or mild (Hb: 11-13.5 in males and 11-12 g/dL in females); iron deficiency (ID) was defined as transferrin saturation (TSAT) <20% and/or ferritin <100 ng/mL. Primary endpoint was the change of anaemia and ID prevalence between baseline and 6-month visit. Secondary endpoint was the prevalence of clinical inertia to either ESA or iron supplementation, that is, the lack of ESA or iron prescription despite Hb <11 g/dL or ID.

RESULTS

Age was 69 ± 13 years and GFR 27.5 ± 10.0 mL/min/1.73 m(2); male gender, diabetes and prior cardiovascular disease were 57.2, 30.1 and 30.1%, respectively. Prevalence of severe and mild anaemia was 18.0 and 44.0% at baseline and remained unchanged at Month 6 (19.3 and 43.2%). ID was prevalent at both visits (60.1 and 60.9%). Clinical inertia to ESA was similar at baseline and at Month 6 (39.6 and 34.2%, respectively, P = 0.487) and it was less frequent than clinical inertia to iron therapy (75.7 and 72.0%, respectively).

CONCLUSIONS

This study shows that anaemia prevalence is unexpectedly high in the setting of tertiary nephrology care. This was due to a persistent clinical inertia in the anaemia management, remarkable for iron supplementation and less critical, but still significant, for ESA treatment.

Parenteral versus oral iron therapy for adults and children with chronic kidney disease

BACKGROUND

The anaemia seen in chronic kidney disease (CKD) may be exacerbated by iron deficiency. Iron can be provided through different routes, with advantages and drawbacks of each route. It remains unclear whether the potential harms and additional costs of intravenous (IV) compared with oral iron are justified.

OBJECTIVES

To determine the benefits and harms of IV iron supplementation compared with oral iron for anaemia in adults and children with CKD.

SEARCH METHODS

In March 2010 we searched the Cochrane Renal Group's specialised register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE and EMBASE without language restriction.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs in which oral and IV routes of iron administration were compared in adults and children with CKD.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study eligibility, risk of bias, and extracted data. Results were reported as risk ratios (RR) or risk differences (RD) with 95% confidence intervals (CI) for dichotomous outcomes and for continuous outcomes the mean difference (MD) was used or standardised mean difference (SMD) if different scales had been used. Statistical analyses were performed using the random-effects model. Subgroup analysis and univariate meta-regression were performed to investigate between study differences.

MAIN RESULTS

Twenty eight studies (2098 participants) were included. Risk of bias attributes were poorly performed and/or reported with low risk of bias reported in 12 (43%) studies for sequence generation, incomplete outcome reporting and selective outcome reporting and in 6 (16%) studies for allocation concealment. No study was blinded for participants, investigators and outcome assessors but all were considered at low risk of bias because the primary outcome of haemoglobin was a laboratory outcome and unlikely to be influenced by lack of blinding. Haemoglobin (22 studies, 1862 patients: MD 0.90 g/dL, 95% CI 0.44 to 1.37); ferritin (24 studies, 1751 patients: MD 243.25 μg/L, 95% CI 188.74 to 297.75); and transferrin saturation (18 studies, 1457 patients: MD 10.20%, 95% CI 5.56 to 14.83) were significantly increased by IV iron compared with oral iron. There was a significant reduction in erythropoiesis-stimulating agent (ESA) dose in patients receiving dialysis who were treated with IV iron (9 studies, 487 patients: SMD -0.76, 95% CI -1.22 to -0.30). There was a high level of heterogeneity in all analyses. Mortality and cardiovascular morbidity did not differ significantly, but were reported in few studies. Gastrointestinal side effects were more common with oral iron, but hypotensive and allergic reactions were more common with IV iron.

AUTHORS' CONCLUSIONS

The included studies provide strong evidence for increased ferritin and transferrin saturation levels, together with a small increase in haemoglobin, in patients with CKD who were treated with IV iron compared with oral iron. From a limited body of evidence, we identified a significant reduction in ESA requirements in patients treated with IV iron, and found no significant difference in mortality. Adverse effects were reported in only 50% of included studies. We therefore suggest that further studies that focus on patient-centred outcomes are needed to determine if the use of IV iron is justified on the basis of reductions in ESA dose and cost, improvements in patient quality of life, and with few serious adverse effects.