MicroRNA-223-3p levels in serum-derived extracellular vesicles predict regression of M2BPGi-based liver fibrosis after hepatitis C virus eradication by direct-acting antiviral agents.

BACKGROUND: We retrospectively investigated microRNA (miRNA) levels in serum-derived extracellular vesicles (EVs) as predictive indicators for regression of liver fibrosis, after achievement of a sustained virological response (SVR) by direct-acting antiviral (DAA) therapy for chronic hepatitis C (CHC). METHODS: The study subjects were recruited from a historical cohort of 108 CHC patients whose pretreatment serum Mac-2-binding protein glycosylation isomer (M2BPGi) levels were ≥ 2.0 cut-off index (COI). We classified patients with M2BPGi levels < 1.76 and ≥ 1.76 COI at 2 years after the end of treatment (EOT) into the regression and non-regression groups, respectively. Eleven of the patients were assigned to the discovery set, and we comprehensively investigated the miRNAs contained in serum-derived EVs at 24 weeks after the EOT (EOT24W), using RNA sequencing. The remaining 97 patients were assigned to the validation set, and reproducibility was verified by quantitative real-time PCR. RESULTS: Through analysis of the discovery and validation sets, we identified miR-223-3p and miR-1290 as candidate predictors. Subsequently, we analyzed various clinical data, including these candidate miRNAs. Multivariate analyses revealed that the levels of miR-223-3p at EOT24W were significantly associated with regression of M2BPGi-based liver fibrosis (Odds ratio: 1.380; P = 0.024). Consistent results were obtained, even when the serum M2BPGi levels were aligned by propensity score matching and in patients with advanced M2BPGi-based liver fibrosis (pretreatment M2BPGi levels ≥ 3.3 COI). CONCLUSIONS: The miR-223-3p level in serum-derived EVs at EOT24W is a feasible predictor of regression of M2BPGi-based liver fibrosis after achievement of an SVR by DAA therapy.

The quality of life and work productivity are affected by the presence of nausea/vomiting in patients taking iron preparations for heavy menstrual bleeding or anemia: a population-based cross-sectional survey in Japan.

BACKGROUND: Patients with iron deficiency anemia are treated with iron preparations, but gastrointestinal symptoms such as nausea and vomiting occur frequently. These symptoms may negatively affect the quality of life and work productivity in patients with iron deficiency anemia. This study assessed the impact of nausea and vomiting on the quality of life and work productivity of patients taking iron preparations for heavy menstrual bleeding or anemia. METHODS: An online survey was conducted among patients taking iron preparations for heavy menstrual bleeding or anemia. Demographic data and information about medication use and the health condition were collected. The patients were asked to answer the 5-level EQ-5D version, and work productivity and activity impairment questionnaires. The outcomes were reported by patients in the presences of nausea, vomiting, and nausea or vomiting. The association with the 5-level EQ-5D version utility score for the severity and frequency of the symptoms were also assessed. RESULTS: A total of 385 patients were enrolled, and 96 were patients with nausea or vomiting, of which 94 were with nausea and 27 were with vomiting. The 5-level EQ-5D version utility scores for the patients with nausea, vomiting, and nausea or vomiting were significantly lower than those of the patients without these symptoms (p < 0.001 for each). The 5-level EQ-5D version utility score was correlated with the severity of nausea and the frequency of vomiting per day (p < 0.001 for each). As for the work productivity and activity impairment, the presenteeism, the overall work impairment, and the activity impairment of the patients with nausea, vomiting, and nausea or vomiting were significantly higher than those without these symptoms (p < 0.001 for each). The absenteeism was slightly higher trend was observed, but not significant. CONCLUSION: Patients taking iron preparations who have nausea or vomiting experience a significant burden in terms of poorer quality of life and higher work productivity impairment. TRIAL REGISTRATION: UMIN000045700 ( http://www.umin.ac.jp/ctr/ ). Registered on October 11, 2021.

A mitochondrial NADPH-cholesterol axis regulates extracellular vesicle biogenesis to support hematopoietic stem cell fate.

Mitochondrial fatty acid oxidation (FAO) is essential for hematopoietic stem cell (HSC) self-renewal; however, the mechanism by which mitochondrial metabolism controls HSC fate remains unknown. Here, we show that within the hematopoietic lineage, HSCs have the largest mitochondrial NADPH pools, which are required for proper HSC cell fate and homeostasis. Bioinformatic analysis of the HSC transcriptome, biochemical assays, and genetic inactivation of FAO all indicate that FAO-generated NADPH fuels cholesterol synthesis in HSCs. Interference with FAO disturbs the segregation of mitochondrial NADPH toward corresponding daughter cells upon single HSC division. Importantly, we have found that the FAO-NADPH-cholesterol axis drives extracellular vesicle (EV) biogenesis and release in HSCs, while inhibition of EV signaling impairs HSC self-renewal. These data reveal the existence of a mitochondrial NADPH-cholesterol axis for EV biogenesis that is required for hematopoietic homeostasis and highlight the non-stochastic nature of HSC fate determination.

Resilient anatomy and local plasticity of naive and stress haematopoiesis.

The bone marrow adjusts blood cell production to meet physiological demands in response to insults. The spatial organization of normal and stress responses are unknown owing to the lack of methods to visualize most steps of blood production. Here we develop strategies to image multipotent haematopoiesis, erythropoiesis and lymphopoiesis in mice. We combine these with imaging of myelopoiesis1 to define the anatomy of normal and stress haematopoiesis. In the steady state, across the skeleton, single stem cells and multipotent progenitors distribute through the marrow enriched near megakaryocytes. Lineage-committed progenitors are recruited to blood vessels, where they contribute to lineage-specific microanatomical structures composed of progenitors and immature cells, which function as the production sites for each major blood lineage. This overall anatomy is resilient to insults, as it was maintained after haemorrhage, systemic bacterial infection and granulocyte colony-stimulating factor (G-CSF) treatment, and during ageing. Production sites enable haematopoietic plasticity as they differentially and selectively modulate their numbers and output in response to insults. We found that stress responses are variable across the skeleton: the tibia and the sternum respond in opposite ways to G-CSF, and the skull does not increase erythropoiesis after haemorrhage. Our studies enable in situ analyses of haematopoiesis, define the anatomy of normal and stress responses, identify discrete microanatomical production sites that confer plasticity to haematopoiesis, and uncover unprecedented heterogeneity of stress responses across the skeleton.

Effect of ferric citrate hydrate on fibroblast growth factor 23 and platelets in non-dialysis-dependent chronic kidney disease and non-chronic kidney disease patients with iron deficiency anemia.

BACKGROUND: Iron deficiency anemia (IDA) increases levels of C-terminal fibroblast growth factor 23 (cFGF23) and platelet count (PLT), each of which is associated with cardiovascular events. Therefore, we hypothesized that iron replacement with ferric citrate hydrate (FC) would decrease cFGF23 levels and PLT in patients with IDA. METHODS: In a randomized, open-label, multicenter, 24-week clinical trial, patients with non-dialysis-dependent chronic kidney disease (CKD) and non-CKD complicated by IDA (8.0 ≤ hemoglobin < 11.0 g/dL; and serum ferritin < 50 ng/mL [CKD]; < 12 ng/mL [non-CKD]) were randomized 1:1 to FC-low (500 mg: approximately 120 mg elemental iron/day) or FC-high (1000 mg: approximately 240 mg elemental iron/day). If sufficient iron replacement had been achieved after week 8, further treatment was discontinued. RESULTS: Seventy-three patients were allocated to FC-low (CKD n = 21, non-CKD n = 15) and FC-high (CKD n = 21, non-CKD n = 16). Regardless of CKD status, FC increased serum ferritin and transferrin saturation, did not change intact FGF23 or serum phosphorus, but decreased cFGF23. In FC-low group, median changes in cFGF23 from baseline to week 8 were -58.00 RU/mL in CKD and -725.00 RU/mL in non-CKD; in FC-high group, the median changes were -66.00 RU/mL in CKD and -649.50 RU/mL in non-CKD. By week 8, FC treatment normalized PLT in all patients with high PLT at baseline (>35.2 × 104/µL; FC-low: 1 CKD, 8 non-CKD; FC-high: 3 CKD, 8 non-CKD). CONCLUSION: Regardless of CKD status, iron replacement with FC decreased elevated cFGF23 levels and normalized elevated PLT in patients with IDA. CLINICAL TRIAL REGISTRATION NUMBER: jRCT2080223943.

Impact of nausea/vomiting on EQ-5D-5L utility scores in patients taking iron preparations for heavy menstrual bleeding or anemia.

BACKGROUND: The purpose of this study was to establish an estimating equation to predict the 5-level EQ-5D version (EQ-5D-5L) utility score in patients taking iron preparations for heavy menstrual bleeding (HMB) or anemia and to evaluate whether the presence of nausea or vomiting was a significant predictor of EQ-5D-5L-based quality of life. METHODS: A cross-sectional survey was conducted to collect EQ-5D-5L utility scores and other patient reported outcomes from 385 patients taking iron preparations for HMB or anemia who were selected from the disease patient panel. Using the utility scores as objective variables, explanatory variable candidates were selected considering correlations, multicollinearity, and clinical validity. Predicting models were constructed using regression-based models (linear model, generalized linear model (GLM), Tobit model). Stepwise regression method was applied for selecting statistically significant (p < 0.05) predictors. Goodness-of-fit of models were assessed by mean absolute error and mean squared error (MSE). RESULTS: The EQ-5D-5L utility scores (mean ± standard deviation) of 96 patients with nausea/vomiting and 289 patients without nausea/vomiting were 0.67 ± 0.16 and 0.84 ± 0.14, respectively (p < 0.001). The presence of nausea/vomiting was shown to be the most significant factor reducing the utility score in the statistical models using the explanatory variable candidates selected in the study. As the results of the goodness-of-fit test, GLM with the smallest MSE was selected to establish the estimating equation. CONCLUSION: The estimating equation to predict the EQ-5D-5L utility scores in patients taking iron preparations for HMB or anemia was established. The presence of nausea/vomiting was found to be a factor significantly reducing utility scores, with a decrement of the value estimated to be -0.117. TRIAL REGISTRATION: UMIN000045700 ( http://www.umin.ac.jp/ctr/ ). Registered on October 11, 2021.

Comparative analysis of Tet2 catalytic-deficient and knockout bone marrow over time.

TET2 is a member of the Ten-eleven translocation (Tet) family of DNA dioxygenases that regulate gene expression by promoting DNA demethylation (enzymatic activity) and partnering with chromatin regulatory complexes (nonenzymatic functions). TET2 is highly expressed in the hematopoietic lineage, where its molecular functions are the subject of continuous investigations because of the prevalence of TET2 mutations in hematologic malignancies. Previously, we have implicated Tet2 catalytic and noncatalytic functions in the regulation of myeloid and lymphoid lineages, respectively. However, the impact of these functions of Tet2 on hematopoiesis as the bone marrow ages remains unclear. Here, we conducted comparative transplantations and transcriptomic analyses of 3-, 6-, 9-, and 12-month-old Tet2 catalytic mutant (Mut) and knockout (KO) bone marrow. Tet2 Mut bone marrow of all ages exclusively caused hematopoietic disorders of the myeloid lineage. In contrast, young Tet2 KO bone marrow developed both lymphoid and myeloid diseases, whereas older Tet2 KO bone marrow predominantly elicited myeloid disorders with shorter latency than age-matched Tet2 Mut bone marrow. We identified robust gene dysregulation in Tet2 KO Lin- cells at 6 months that involved lymphoma and myelodysplastic syndrome and/or leukemia-causing genes, many of which were hypermethylated early in life. There was a shift from lymphoid to myeloid gene deregulation in Tet2 KO Lin- cells with age, underpinning the higher incidence of myeloid diseases. These findings expand on the dynamic regulation of bone marrow by Tet2 and show that its catalytic-dependent and -independent roles have distinct impacts on myeloid and lymphoid lineages with age.

Iron absorption and phosphate-lowering effects of ferric citrate hydrate are not influenced by gastric acid secretion inhibitors in patients with chronic kidney disease: a retrospective post hoc analysis.

BACKGROUND: Ferric citrate hydrate (FC), an oral iron product is approved as iron preparation for iron deficiency anemia and phosphate binder for chronic kidney disease (CKD). We investigated whether gastric acid secretion inhibitors (GASI) influenced on iron absorption and phosphate-lowering effects of FC. METHODS: Two phase 3 studies of FC for treatment of hyperphosphatemia in CKD patients (non-dialysis-dependent, 12 weeks, and hemodialysis, 52 weeks), were retrospectively analyzed. Patients were divided into with or without concomitant GASI and levels of iron- and phosphate-related parameters were analyzed. RESULTS: In non-dialysis study (FC, 60 patients; placebo, 30 patients), 14 FC patients and 14 placebo patients used GASI. No significant differences were found between the FC and placebo groups for adjusted mean differences (95% CI) of changes from baseline to end of treatment (EOT) in serum ferritin [104.84 ng/mL (35.97, 173.71) with GASI vs 145.30 ng/mL (96.34, 194.25) without GASI, P = 0.34], and transferrin saturation (TSAT) [12.56% (- 0.83, 25.95) with GASI vs 18.56% (8.15, 28.98) without GASI, P = 0.49]. In hemodialysis study, 95/180 patients used GASI. Mean changes (SD) from baseline to EOT in serum ferritin were 166.32 ng/mL (153.70) with GASI and 155.16 ng/mL (139.47) without GASI, and for TSAT were 16.60% (19.44) with GASI and 16.02% (18.81) without GASI. In both studies, there were no differences in the changes from baseline to EOT in serum phosphate between with and without GASI cohorts. CONCLUSION: GASI did not influence on the changes in serum ferritin, TSAT and serum phosphate by FC administration.

Ivermectin Inhibits HBV Entry into the Nucleus by Suppressing KPNA2.

Hepatitis B virus (HBV) specifically infects human hepatocytes and increases the risks of cirrhosis and liver cancer. Currently, nucleic acid analogs are the main therapeutics for chronic hepatitis caused by HBV infection. Although nucleic acid analogs can eliminate HBV DNA by inhibiting HBV reverse transcriptase, they cannot lead to negative conversion of covalently closed circular DNA (cccDNA) and hepatitis B surface antigen (HBsAg). In this study, we revealed that the antifilarial drug ivermectin suppresses HBV production by a different mechanism from the nucleic acid analog entecavir or Na+ taurocholate co-transporting polypeptide-mediated entry inhibitor cyclosporin A. Ivermectin reduced the levels of several HBV markers, including HBsAg, in HBV-infected human hepatocellular carcinoma cells (HepG2-hNTCP-C4 cells) and humanized mouse hepatocytes (PXB hepatocytes). In addition, ivermectin significantly decreased the expression of HBV core protein and the nuclear transporter karyopherin α2 (KPNA2) in the nuclei of HepG2-hNTCP-C4 cells. Furthermore, depletion of KPNA1-6 suppressed the production of cccDNA. These results suggest that KPNA1-6 is involved in the nuclear import of HBV and that ivermectin suppresses the nuclear import of HBV by inhibiting KPNA2. This study demonstrates the potential of ivermectin as a novel treatment for hepatitis B.

NPM1 ablation induces HSC aging and inflammation to develop myelodysplastic syndrome exacerbated by p53 loss.

Myelodysplastic syndrome (MDS) is characterized by ineffective hematopoiesis with morphologic dysplasia and a propensity to transform into overt acute myeloid leukemia (AML). Our analysis of two cohorts of 20 MDS and 49 AML with multi-lineage dysplasia patients shows a reduction in Nucleophosmin 1 (NPM1) expression in 70% and 90% of cases, respectively. A mouse model of Npm1 conditional knockout (cKO) in hematopoietic cells reveals that Npm1 loss causes premature aging of hematopoietic stem cells (HSCs). Mitochondrial activation in Npm1-deficient HSCs leads to aberrant activation of the NLRP3 inflammasome, which correlates with a developing MDS-like phenotype. Npm1 cKO mice exhibit shortened survival times, and expansion of both the intra- and extra-medullary myeloid populations, while evoking a p53-dependent response. After transfer into a p53 mutant background, the resulting Npm1/p53 double KO mice develop fatal leukemia within 6 months. Our findings identify NPM1 as a regulator of HSC aging and inflammation and highlight the role of p53 in MDS progression to leukemia.

Ferric citrate hydrate is associated with a reduced cost of drugs and a smaller change in red blood cell distribution width.

The ASTRIO study was a randomised, multicentre, 24-week study that compared the effects of ferric citrate hydrate (FC) and non-iron-based phosphate binders (control) on anaemia management in haemodialysis (HD) patients receiving erythropoiesis-stimulating agents (ESAs). In that study, FC reduced the doses of ESAs and intravenous iron without affecting haemoglobin (Hb); however, the cost-effectiveness of FC was unclear. We retrospectively implemented a cost-effectiveness analysis comparing the incremental cost-effectiveness ratios (ICERs) in FC (n = 42) and control (n = 40) groups in patients with serum phosphate and Hb controlled within the ranges of 3.5-6.0 mg/dL and 10-12 g/dL, respectively. Costs included drug costs of phosphate binders, ESAs, and intravenous iron. Elevated red cell distribution width (RDW) has been reported to be associated with mortality in HD patients and was therefore used as an effectiveness index. The mean (95% confidence interval) differences in drug costs and RDW between the FC and control groups were US$ - 421.36 (- 778.94 to - 63.78, p = 0.02) and - 0.83% (- 1.61 to - 0.05, p = 0.04), respectively. ICER indicated a decrease of US$ 507.66 per 1% decrease in RDW. FC was more cost-effective than non-iron-based phosphate binders. Iron absorbed via FC could promote erythropoiesis and contribute to renal anaemia treatment.

Droplet digital PCR assay provides intrahepatic HBV cccDNA quantification tool for clinical application.

The persistence of covalently closed circular DNA (cccDNA) poses a major obstacle to curing chronic hepatitis B (CHB). Here, we used droplet digital PCR (ddPCR) for cccDNA quantitation. The cccDNA-specific ddPCR showed high accuracy with the dynamic range of cccDNA detection from 101 to 105 copies/assay. The ddPCR had higher sensitivity, specificity and precisely than qPCR. The results of ddPCR correlated closely with serum HB core-related antigen and HB surface antigen (HBsAg) in 24 HBV-infected human-liver-chimeric mice (PXB-mice). We demonstrated that in 2 PXB-mice after entecavir treatment, the total cccDNA content did not change during liver repopulation, although the cccDNA content per hepatocyte was reduced after the treatment. In the 6 patients with HBV-related hepatocellular carcinoma, ddPCR detected cccDNA in both tumor and non-tumor tissues. In 13 HBeAg-negative CHB patients with pegylated interferon alpha-2a, cccDNA contents from paired biopsies were more significantly reduced in virological response (VR) than in non-VR at week 48 (p = 0.0051). Interestingly, cccDNA levels were the lowest in VR with HBsAg clearance but remained detectable after the treatment. Collectively, ddPCR revealed that cccDNA content is stable during hepatocyte proliferation and persists at quantifiable levels, even after serum HBsAg clearance.

Leukemia Stem Cells as a Potential Target to Achieve Therapy-Free Remission in Chronic Myeloid Leukemia.

Leukemia stem cells (LSCs, also known as leukemia-initiating cells) not only drive leukemia initiation and progression, but also contribute to drug resistance and/or disease relapse. Therefore, eradication of every last LSC is critical for a patient's long-term cure. Chronic myeloid leukemia (CML) is a myeloproliferative disorder that arises from multipotent hematopoietic stem and progenitor cells. Tyrosine kinase inhibitors (TKIs) have dramatically improved long-term outcomes and quality of life for patients with CML in the chronic phase. Point mutations of the kinase domain of BCR-ABL1 lead to TKI resistance through a reduction in drug binding, and as a result, several new generations of TKIs have been introduced to the clinic. Some patients develop TKI resistance without known mutations, however, and the presence of LSCs is believed to be at least partially associated with resistance development and CML relapse. We previously proposed targeting quiescent LSCs as a therapeutic approach to CML, and a number of potential strategies for targeting insensitive LSCs have been presented over the last decade. The identification of specific markers distinguishing CML-LSCs from healthy HSCs, and the potential contributions of the bone marrow microenvironment to CML pathogenesis, have also been explored. Nonetheless, 25% of CML patients are still expected to switch TKIs at least once, and various TKI discontinuation studies have shown a wide range in the incidence of molecular relapse (from 30% to 60%). In this review, we revisit the current knowledge regarding the role(s) of LSCs in CML leukemogenesis and response to pharmacological treatment and explore how durable treatment-free remission may be achieved and maintained after discontinuing TKI treatment.

Patient Preferences for Attributes of Chemotherapy for Lung Cancer: Discrete Choice Experiment Study in Japan.

Our study objective was to determine lung cancer chemotherapy attributes that are important to patients in Japan. A discrete choice experiment survey in an anonymous web-based questionnaire format with a reward was completed by 200 lung cancer patients in Japan from November 25, 2019, to November 27, 2019. The relative importance of patient preferences for each attribute was estimated using a conditional logit model. A hierarchical Bayesian logit model was also used to estimate the impact of each demographic characteristic on the relative importance of each attribute. Of the 200 respondents, 191 with consistent responses were included in the analysis. In their preference, overall survival was the most important, followed by diarrhea, nausea, rash, bone marrow suppression (BMS), progression-free survival, fatigue, interstitial lung disease, frequency of administration, and duration of administration. The preferences were influenced by demographic characteristics (e.g., gender and age) and disease background (e.g., cancer type and stage). Interestingly, the experience of cancer drug therapies and adverse events had a substantial impact on the hypothetical drug preferences. For the Japanese lung cancer patients, improved survival was the most important attribute that influenced their preference for chemotherapy, followed by adverse events, including diarrhea, nausea, rash, and BMS. The preferences varied depending on the patient's demographic and experience. As drug attributes can affect patient preferences, pharmaceutical companies should be aware of the patient preferences and develop drugs that respond to segmented market needs.

Electron transport chain complex II sustains high mitochondrial membrane potential in hematopoietic stem and progenitor cells.

The role of mitochondria in the fate determination of hematopoietic stem and progenitor cells (HSPCs) is not solely limited to the switch from glycolysis to oxidative phosphorylation, but also involves alterations in mitochondrial features and properties, including mitochondrial membrane potential (ΔΨmt). HSPCs have a high ΔΨmt even when the rates of respiration and phosphorylation are low, and we have previously shown that the minimum proton flow through ATP synthesis (or complex V) enables high ΔΨmt in HSPCs. Here we show that HSPCs sustain a unique equilibrium between electron transport chain (ETC) complexes and ATP production. HSPCs exhibit high expression of ETC complex II, which sustains complex III in proton pumping, although the expression levels of complex I or V are relatively low. Complex II inhibition by TTFA caused a substantial decrease of ΔΨmt, particularly in HSPCs, while the inhibition of complex I by Rotenone mainly affected mature populations. Functionally, pharmacological inhibition of complex II reduced in vitro colony-replating capacity but this was not observed when complex I was inhibited, which supports the distinct roles of complex I and II in HSPCs. Taken together, these data highlight complex II as a key regulator of ΔΨmt in HSPCs and open new and interesting questions regarding the precise mechanisms that regulate mitochondrial control to maintain hematopoietic stem cell self-renewal.

Non-catalytic Roles of Tet2 Are Essential to Regulate Hematopoietic Stem and Progenitor Cell Homeostasis.

The Ten-eleven translocation (TET) enzymes regulate gene expression by promoting DNA demethylation and partnering with chromatin modifiers. TET2, a member of this family, is frequently mutated in hematological disorders. The contributions of TET2 in hematopoiesis have been attributed to its DNA demethylase activity, and the significance of its nonenzymatic functions has remained undefined. To dissect the catalytic and non-catalytic requirements of Tet2, we engineered catalytically inactive Tet2 mutant mice and conducted comparative analyses of Tet2 mutant and Tet2 knockout animals. Tet2 knockout mice exhibited expansion of hematopoietic stem and progenitor cells (HSPCs) and developed myeloid and lymphoid disorders, while Tet2 mutant mice predominantly developed myeloid malignancies reminiscent of human myelodysplastic syndromes. HSPCs from Tet2 knockout mice exhibited distinct gene expression profiles, including downregulation of Gata2. Overexpression of Gata2 in Tet2 knockout bone marrow cells ameliorated disease phenotypes. Our results reveal the non-catalytic roles of TET2 in HSPC homeostasis.

Randomised clinical trial of ferric citrate hydrate on anaemia management in haemodialysis patients with hyperphosphataemia: ASTRIO study.

Ferric citrate hydrate (FC) is an iron-based phosphate binder approved for hyperphosphataemia in patients with chronic kidney disease. We conducted a randomised controlled trial to evaluate the effects of FC on anaemia management in haemodialysis patients with hyperphosphataemia. We 1:1 randomised 93 patients who were undergoing haemodialysis and being treated with non-iron-based phosphate binders and erythropoiesis-stimulating agents (ESA) to receive 24 weeks of FC or to continue their non-iron-based phosphate binders (control) in a multicentre, open-label, parallel-design. Phosphate level was controlled within target range (3.5-6.0 mg/dL). The primary endpoint was change in ESA dose from baseline to end of treatment. Secondary endpoints were changes in red blood cell, iron and mineral, and bone-related parameters. Compared with control, FC reduced ESA dose [mean change (SD), -1211.8 (3609.5) versus +1195 (6662.8) IU/week; P = 0.03] without significant differences in haemoglobin. FC decreased red blood cell distribution width (RDW) compared with control. While there were no changes in serum phosphate, FC reduced C-terminal fibroblast growth factor (FGF) 23 compared with control. The incidence of adverse events did not differ significantly between groups. Despite unchanged phosphate and haemoglobin levels, FC reduced ESA dose, RDW, and C-terminal FGF23 compared with control.

Metabolism as master of hematopoietic stem cell fate.

HSCs have a fate choice when they divide; they can self-renew, producing new HSCs, or produce daughter cells that will mature to become committed cells. Technical challenges, however, have long obscured the mechanics of these choices. Advances in flow-sorting have made possible the purification of HSC populations, but available HSC-enriched fractions still include substantial heterogeneity, and single HSCs have proven extremely difficult to track and observe. Advances in single-cell approaches, however, have led to the identification of a highly purified population of hematopoietic stem cells (HSCs) that make a critical contribution to hematopoietic homeostasis through a preference for self-renewing division. Metabolic cues are key regulators of this cell fate choice, and the importance of controlling the population and quality of mitochondria has recently been highlighted to maintain the equilibrium of HSC populations. Leukemic cells also demand tightly regulated metabolism, and shifting the division balance of leukemic cells toward commitment has been considered as a promising therapeutic strategy. A deeper understanding of precisely how specific modes of metabolism control HSC fate is, therefore, of great biological interest, and more importantly will be critical to the development of new therapeutic strategies that target HSC division balance for the treatment of hematological disease.

Membrane-potential compensation reveals mitochondrial volume expansion during HSC commitment.

Proper control of mitochondrial function is a key factor in the maintenance of hematopoietic stem cells (HSCs). Mitochondrial content is commonly measured by staining with fluorescent cationic dyes. However, dye staining can be affected, not only by xenobiotic efflux pumps, but also by dye intake, which is dependent on the negative charge of mitochondria. Therefore, mitochondrial membrane potential (ΔΨmt) must be considered in these measurements because a high ΔΨmt due to respiratory chain activity can enhance dye intake, leading to the overestimation of mitochondrial volume. Here, we show that HSCs exhibit the highest ΔΨmt of the hematopoietic lineages and, as a result, ΔΨmt-independent methods most accurately assess the relatively low mitochondrial volumes and DNA amounts of HSC mitochondria. Multipotent progenitor stage or active HSCs display expanded mitochondrial volumes, which decline again with further maturation. Further characterization of the controlled remodeling of the mitochondrial landscape at each hematopoietic stage will contribute to a deeper understanding of the mitochondrial role in HSC homeostasis.