Hyporesponsiveness to erythropoiesis-stimulating agent in non-dialysis-dependent CKD patients: The BRIGHTEN study.

Among non-dialysis-dependent chronic kidney disease (ND-CKD) patients, a low hematopoietic response to erythropoiesis-stimulating agents (ESAs) is a predictor for poor renal and cardiovascular outcome. To assess the method for evaluating hyporesponsiveness to ESA in patients with ND-CKD, a multicenter, prospective, observational study of 1,980 adult patients with ND-CKD with renal anemia was conducted. Darbepoetin alfa (DA) and iron supplement administrations were provided according to the recommendation of the attached document and the guidelines of JSDT (Japanese Society of Dialysis and Transplantation). The primary outcomes were progression of renal dysfunction and major adverse cardiovascular events. ESA responsiveness was assessed using pre-defined candidate formulae. During the mean follow-up period of 96 weeks, renal and cardiovascular disease (CVD) events occurred in 683 (39.6%) and 174 (10.1%) of 1,724 patients, respectively. Among pre-set candidate formulae, the one expressed by dividing the dose of DA by Hb level at the 12-week DA treatment was statistically significant in predicting renal (hazard ratio [HR], 1.449; 95% confidence interval [CI], 1.231-1.705; P<0.0001) and CVD events (HR, 1.719; 95% CI, 1.239-2.386; P = 0.0010). The optimum cut-off values for both events were close to 5.2. In conclusion, hyporesponsiveness to ESA in ND-CKD cases, which is associated with a risk for renal and CVD events, may be evaluated practicably as the dose of DA divided by the Hb level at the 12-week DA treatment, and the cut-off value of this index is 5.2. A search for the causes of poor response and measures for them should be recommended in such patients. Trial registration: ClinicalTrials. gov Identifier: NCT02136563; UMIN Clinical Trial Registry Identifier: UMIN000013464.

Initial responsiveness to darbepoetin alfa and its contributing factors in non-dialysis chronic kidney disease patients in Japan.

BACKGROUND: Hyporesponsiveness to erythropoiesis-stimulating agents (ESAs) is associated with cardiovascular events and poor renal outcome in patients with chronic kidney disease (CKD). This study aimed to investigate the initial responsiveness to darbepoetin alfa (DA) and its contributing factors using the data from the BRIGHTEN. METHODS: Of 1980 patients enrolled at 168 facilities, 1695 were included in this analysis [285 patients were excluded mainly due to lack of hemoglobin (Hb) values]. The initial ESA response index (iEResI) was defined as a ratio of Hb changes over 12 weeks after DA administration per weight-adjusted total DA dose and contributing factors to iEResI were analyzed. RESULTS: The mean age was 70 ± 12 years (male 58.8%; diabetic nephropathy 27.6%). The median creatinine and mean Hb levels at DA initiation were 2.62 mg/dL and 9.8 g/dL, respectively. The most frequent number of DA administration during 12 weeks was 3 times (41.1%), followed by 4 (15.6%) times with a wide distribution of the total DA dose (15-900 µg). Remarkably, 225 patients (13.3%) did not respond to DA. Multivariate analysis showed that male gender, hypoglycemic agent use, iron supplementation, high eGFR, low Hb, low CRP, low NT-proBNP, and low urinary protein-creatinine ratio were independently associated with better initial response to DA (P = < 0.0001, 0.0108, < 0.0001, 0.0476, < 0.0001, 0.0004, 0.0435, and 0.0009, respectively). CONCLUSIONS: Non-responder to DA accounted for 13.3% of patients with non-dialysis CKD. Iron supplementation, low CRP, low NT-proBNP, and less proteinuria were predictive and modifiable factors associated with better initial response to DA.

Inhibition of the H3K4 methyltransferase MLL1/WDR5 complex attenuates renal senescence in ischemia reperfusion mice by reduction of p16INK4a.

Renal function declines with aging and is pathologically characterized by chronic inflammation and fibrosis. Renal senescence is induced not only by aging but also by various stimuli, including ischemia reperfusion injury. Recently, the accumulation of p16INK4a-positive cells in the kidney has been considered a molecular feature of renal senescence, with the p16INK4a gene reportedly regulated by mixed-lineage leukemia 1 (MLL1)/WD-40 repeat protein 5 (WDR5)-mediated histone 3 lysine 4 trimethylation (H3K4me3). Here, we determined whether inhibition of MLL1/WDR5 activity attenuates renal senescence, inflammation, and fibrosis in mice with ischemia reperfusion injury and in cultured rat renal fibroblasts. MM-102 or OICR-9429, both MLL1/WDR5 protein-protein interaction inhibitors, and small interfering RNA (siRNA) for MLL1 or WDR5 suppressed the expression of p16INK4a in mice with ischemia reperfusion injury, accompanied by downregulation of H3K4me3 expression. MM-102 attenuated renal fibrosis and inflammation in the kidney of mice with ischemia reperfusion injury. Moreover, in vitro study showed that transforming growth factor-ß1 induced the expression of MLL1, WDR5, H3K4me3, and p16INK4a. Finally, chromatin immunoprecipitation identified the p16INK4a promoter at an H3K4me3 site in renal fibroblasts. Thus, our findings show that H3K4me3 inhibition ameliorates ischemia reperfusion-induced renal senescence along with fibrosis and inflammation.

Long-term maintenance of hemoglobin levels in hemodialysis patients treated with bi-weekly epoetin beta pegol switched from darbepoetin alfa: a single-center, 12-month observational study in Japan.

Recent evidence on maintenance administration of epoetin beta pegol, a continuous erythropoiesis receptor activator (CERA), in dialysis patients shows the clinical benefit of bi-weekly administration (Q2W) in improving hematopoiesis and iron use efficiency. We undertook a single-center observational study of 33 Japanese maintenance dialysis patients, whose anemia had been kept stable through weekly administration (Q1W) of darbepoetin (DA), to evaluate the effectiveness of CERA Q2W switched from DA in maintaining hemoglobin (Hb) levels over a 12-month period. The target Hb level was 10.0-12.0 g/dL. Throughout the 12-month period, the mean Hb was stably maintained at 10.5-10.8 g/dL, 69.7-87.9% of the patients achieving the target Hb level. The mean CERA dose was within the range of 62.9-78.8 µg/2 weeks. The average CERA dose adjustment frequency after switching was low at 0.42-0.67 times/3 months. In both subgroups stratified by the DA dose prior to the switch, Hb levels were kept stable during CERA administration; however, in the low-dose group (10-20 µg/week of DA), the CERA and iron doses decreased over time, whereas in the high-dose group (30-60 µg/week of DA) they remained unchanged. CERA Q2W achieved long-term successful anemia management in Japanese maintenance dialysis patients after switching from DA Q1W. CERA dose was adjusted based on an overall consideration of past changes in Hb levels, erythropoiesis-stimulating agent and iron doses. Subgroup analysis showed the CERA dose in the low-dose group decreased continuously, due possibly to a long-term improvement in iron use efficiency.

Oral iron supplementation with sodium ferrous citrate reduces the serum intact and c-terminal fibroblast growth factor 23 levels of maintenance haemodialysis patients.

AIM: Iron deficiency stimulates fibroblast growth factor 23 (FGF23) transcription. This study aimed to determine whether oral ferrous iron (Fe2+ ) reduces the serum FGF23 levels of iron-deficient maintenance haemodialysis (MHD) patients in the same way as oral ferric iron (Fe3+ ) METHODS: Thirty-one MHD patients with iron deficiency were enrolled in this prospective study. Patients who had taken iron supplements during the 8 weeks before the study were excluded. The patients' iron stores and their serum FGF23, phosphate, intact parathyroid hormone (iPTH), albumin, C-reactive protein (CRP), and albumin-adjusted calcium (Ca) levels were examined at the baseline and after 3 months' treatment with sodium ferrous citrate (Fe2+ ). RESULTS: The patients' transferrin saturation values and serum iron and ferritin levels were significantly increased after 3 months' treatment (P < 0.01), as were their serum albumin levels (P < 0.05). Conversely, their serum intact FGF23 (iFGF23) [1820 (342-4370) vs 1240 (214-2940) pg/mL, P < 0.05], C-terminal FGF23 (cFGF23) [309 (120-1211) vs 259 (99-600) pg/mL, P < 0.05)], and CRP levels (P < 0.01) were significantly reduced after 3 months' treatment. No changes were detected in the patients' serum iFGF23:cFGF23 ratios or their serum phosphate, Ca, or iPTH levels. The changes in the patients' serum iFGF23 and cFGF23 levels induced by sodium ferrous citrate supplementation were shown to be attributable to changes in their serum ferritin levels (P < 0.05). CONCLUSION: Short-term oral iron supplementation with sodium ferrous citrate replenished the iron stores and reduced the serum iFGF23 and cFGF23 levels of MHD patients with iron deficiency without affecting their serum phosphate, Ca, or iPTH levels.