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Background/Objectives: Iron and phosphate are both vital to many biological cellular processes with central roles in energy metabolism, cellular proliferation and nucleic acid synthesis. Regulatory pathways in some of these metabolic pathways may intersect at fibroblast growth factor 23 (FGF23), a major phosphate regulatory hormone. Iron is reported to induce hypophosphataemia in rare cases, and recent reports suggest that iron deficiency may upregulate FGF23 synthesis by mechanisms involving hypoxia-inducible factor 1[alpha] (HIF1[alpha]). Our objective was to evaluate the effect of administration of intravenous iron polymaltose on intact and c-terminal FGF23 (i:cFGF23) ratios in two independent cohorts of patients, iron-deficient but non-inflamed patients and haemodialysis (HD)-dependent patients, and to examine the balance of synthesis and degradation. Subjects/Methods: We studied biochemical effects of intravenous iron polymaltose on both iFGF23 and cFGF23 fragments and their ratios in two patient groups: iron-deficient patients with normal renal function (ID-norm) and HD patients receiving iron supplementation (HD-ESKD) at a single institution. Patients were tested at baseline, day 4 and day 12 post iron administration. Results: Parenteral iron polymaltose resulted in increased i:cFGF23 ratios in ID-norm patients where circulating cFGF23 levels decreased with no appreciable effect on iFGF23, whereas no significant changes in i:cFGF23 ratios were observed in HD-ESKD patients following intravenous administration of 100mg iron polymaltose. Conclusions: Dysregulation of intracellular FGF23-processing mechanisms may be related to iron deficiency per se rather than iron repletion with iron polymaltose. In ID-norm, i:cFGF23 ratios altered with iron administration without significant clinical alterations in mineral parameters, implying that other regulatory mechanisms may be important. Finally, iron supplementation in HD-ESKD patients does not appear to significantly affect i:cFGF23 ratios already disturbed by a chronic inflammatory or functionally iron-deficient state., Author(s): S-J Tan [sup.1] [sup.2] , S Satake [sup.1] , E R Smith [sup.1] , N D Toussaint [sup.1] [sup.2] , T D Hewitson [sup.1] [sup.2] , S G Holt [...]

Background: Urinary tract infections (UTIs) are the commonest infectious complication in kidney transplant recipients (KTRs). No recommendations exist regarding treatment of asymptomatic bacteriuria. We aimed to identify potential risk factors and microbiological profile for UTIs, the role of treatment of asymptomatic bacteriuria, and effects on graft outcomes of bacteriuria within the first year post-transplantation., Methods: We performed a retrospective analysis of UTIs in KTRs transplanted between January 2012 and December 2013 in 2 transplantation centers. Patients were routinely commenced on prophylactic sulfamethoxazole-trimethoprim. Clinical and microbiological data were analyzed for the first year following transplantation., Results: In all, 276 KTRs were evaluated; 67% were men, with a mean age of 51 years. At 12 months post-transplantation 158 (57%) KTRs had no bacteriuria, 75 (27%) had asymptomatic bacteriuria, 21 (8%) had symptomatic UTIs without further complication, and 22 (8%) with UTIs developed either pyelonephritis or urosepsis. Most frequent pathogens identified were Enterococcus faecalis and Escherichia coli, and 36% of organisms were multidrug resistant. Female sex was a risk factor for infection (P = .002), and presence of a double-J ureteral stent significantly increased the risk of asymptomatic bacteriuria and symptomatic UTIs (P = .003). Diabetes, age, and prior transplantation did not increase risk. Presence of infection was not associated with increased rejection, with similar renal function at 12 months. For episodes of bacteriuria (n = 420, asymptomatic n = 324), untreated asymptomatic bacteriuria (n = 185) followed by symptomatic UTI with the same organism was significantly higher (P = .002) compared with cases of treated asymptomatic bacteriuria (n = 139)., Conclusion: Bacteriuria post-kidney transplantation is common, affecting nearly half of KTRs in the first year after transplantation. Treatment of asymptomatic bacteriuria may be beneficial to prevent subsequent episodes of symptomatic UTIs., (Copyright © 2017 Elsevier Inc. All rights reserved.)