Composite dietary antioxidant index is associated with renal anemia: a cross-sectional study.

An increasing evidence suggested that chronic kidney disease (CKD) is closely related to oxidative stress, and dietary antioxidant intake can serve as a primary preventive measure for CKD. However, the relationship between composite dietary antioxidant index (CDAI) and renal anemia is not well understood. We postulated that elevated CDAI levels would be inversely related to a higher likelihood of renal anemia. The standardized calculation of CDAI was performed to investigate the relationship between them by a binary regression model. A non-linear relationship was examined through restricted cubic spline curves, and then pinpointed the inflection point. Subgroup analysis was then used to assess the robustness of the model. Finally 5880 participants were included in the study and a notable correlation between CDAI and renal anemia was found (P < 0.0001). In the multivariate linear regression model with adjustment for all confounding variables, the odds ratio (OR) and 95% confidence interval (CI) was 0.96 (0.94, 0.98; P < 0.0001), A non-linear relationship between CDAI and renal anemia was explored through restricted cubic splines, with a inflection at 6.005. Before the inflection point, for each unit rise in CDAI, the prevalence of renal anemia decreased by 5.7%. Subgroup analysis showed no statistically significant differences in interactions between any subgroups (P > 0.05). Our findings indicated a non-linear negative correlation between CDAI and renal anemia. The causal relationship still needs to be further clarified through large-scale prospective studies.

Renal anemia: from relative insufficiency of EPO to imbalance of erythropoiesis and eryptosis.

Chronic kidney disease has emerged as a major health issue both in China and worldwide. Renal anemia frequently occurs in patients with chronic kidney disease, and its severity and incidence rate increase as the disease progresses. Over the last 30 years, the administration of exogenous EPO and EPO stimulants has been employed to alleviate renal anemia, suggesting that a relative deficiency in EPO may be a primary cause. However, this approach has overshadowed other contributing factors, particularly eryptosis, which results from the reduced lifespan of red blood cells. Numerous studies reveal that there are nephrogenic and extrarenal EPO secretion indicating that an absolute deficiency of EPO is not always present in patients. Therefore, this paper speculates that renal anemia may arise when EPO-driven erythropoiesis fails to adequately compensate for aggravating eryptosis. Other factors including iron metabolism disorder, uremic toxin accumulation, inflammatory state, oxidative stress, and secondary hyperparathyroidism affect EPO reactivity bone marrow hematopoiesis and eryptosis, leading to an imbalance between red blood cell production and destruction, and cause anemia ultimately. More further studies on the pathogenesis and treatment of renal anemia would be expected to provide evidence to support our opinion.

Short-term effect of low-dose roxadustat combined with erythropoiesis-stimulating agent treatment for erythropoietin-resistant anemia in patients undergoing maintenance hemodialysis.

Background: Erythropoietin resistance is present in some patients with chronic kidney disease, especially in those undergoing hemodialysis, and is often treated using roxadustat rather than iron supplements and erythropoiesis-stimulating agents (ESAs). However, some patients cannot afford full doses of roxadustat. This retrospective study investigated the efficacy of low-dose roxadustat combined with recombinant human erythropoietin (rhuEPO) therapy in 39 patients with erythropoietin-resistant renal anemia undergoing maintenance hemodialysis (3-4 sessions/week). Methods: The ability of the combination of low-dose roxadustat and rhuEPO to increase the hemoglobin concentration over 12 weeks was assessed. Markers of iron metabolism were evaluated. Eligible adults received 50-60% of the recommended dose of roxadustat and higher doses of rhuEPO. Results: The mean hemoglobin level increased from 77.67 ± 11.18 g/dL to 92.0 ± 8.35 g/dL after treatment, and the hemoglobin response rate increased to 72%. The mean hematocrit level significantly increased from 24.26 ± 3.99% to 30.04 ± 3.69%. The soluble transferrin receptor level increased (27.29 ± 13.60 mg/L to 38.09 ± 12.78 mg/L), while the total iron binding capacity (49.22 ± 11.29 mg/L to 43.91 ± 12.88 mg/L) and ferritin level (171.05 ± 54.75 ng/mL to 140.83 ± 42.03 ng/mL) decreased. Conclusion: Therefore, in patients with ESA-resistant anemia who are undergoing hemodialysis, the combination of low-dose roxadustat and rhuEPO effectively improves renal anemia and iron metabolism.

Discovery of DS-1093a: An oral hypoxia-inducible factor prolyl hydroxylase inhibitor for the treatment of renal anemia.

Inhibition of the hypoxia-inducible factor prolyl hydroxylase (HIF-PHD) represents a promising strategy for discovering next-generation treatments for renal anemia. We discovered DS44470011 in our previous study, which showed potent in vitro activity and in vivo efficacy based on HIF-PHD inhibition. However, DS44470011 was also found to exert genotoxic effects. By converting the biphenyl structure, which is suspected to be the cause of this genotoxicity, to a 1-phenylpiperidine structure, we were able to avoid genotoxicity and further improve the in vitro activity and in vivo efficacy. Furthermore, through the optimization of pyrimidine derivatives, we discovered DS-1093a, which has a wide safety margin with potent in vitro activity and an optimal pharmacokinetic profile. DS-1093a achieved an increase in hemoglobin levels in an adenine-induced rat model of chronic kidney disease after its continuous administration for 4 days.

Association between magnesium, erythropoietin resistance and mortality: the Japanese Dialysis Outcomes and Practice Patterns Study (J-DOPPS).

Background: Limited data are now available to evaluate the relationship between serum magnesium level, anemia and mortality in the dialysis population. Methods: Using data from the Japanese Dialysis Outcomes and Practice Patterns Study (J-DOPPS) phases 5 and 6, we analyzed the association between serum magnesium (s-Mg) levels and the erythropoiesis-stimulating agents resistance index (ERI) as the primary outcome. To estimate the longitudinal relationship, a mixed-effect model was used with ERI at each 4-month period as the dependent variable and quintiles of s-Mg at the previous 4-month period as the independent variable. We also examined incidence of infectious events, and the all-cause and cardiovascular disease (CVD)-related deaths as secondary outcomes by Cox regression with quintiles of s-Mg at baseline. Results: Of the 4776 participants in J-DOPPS, 1650 were included in the analysis. The median of s-Mg at baseline was 2.5 mg/dL. A significant linear association of s-Mg with ERI (P for trend <.001) was revealed. Low and high s-Mg levels were not associated with the clinical outcomes of interest, except for the highest quintile of s-Mg being significantly associated with lower incidence of all-cause mortality and CVD-related deaths compared with the middle (reference) quintile. Conclusions: We observed that lower s-Mg levels subsequently induced higher ERI and that mild higher s-Mg levels were possibly associated with good rather than poor outcomes in Japanese hemodialysis patients. Adjustment of s-Mg levels may be proposed as a new strategy at a low cost and risk to reduce the risk of premature mortality.

Roxadustat-Induced Central Hypothyroidism in Renal Anemia Patients: Insights From Antineutrophil Cytoplasmic Antibody-Related Vasculitis Cases.

The introduction of hypoxia-inducible factor-prolyl hydroxylase (HIF-PH) inhibitors in Japan in 2019 for treating renal anemia in hemodialysis patients has resulted in an adverse event: central hypothyroidism. Although this adverse event was not widely recognized by the public, it was first documented in Japan in 2021. Despite limited case reports on roxadustat, an oral HIF-PH inhibitor that induces central hypothyroidism, this condition typically improves rapidly upon discontinuation of the drug. In this report, we present rare cases of roxadustat-induced central hypothyroidism in two patients: a woman in her 80s and a man in his 60s, neither of whom had prior thyroid disease. Both patients developed central hypothyroidism shortly after starting roxadustat treatment for renal anemia associated with antineutrophil cytoplasmic antibody-related vasculitis. Notably, neither patient had pituitary tumors or other pituitary hormone disorders. Thyroid function improved with levothyroxine treatment, even when oral roxadustat was continued. Roxadustat may induce central hypothyroidism, highlighting the importance of regularly measuring and evaluating thyroid function when administering this drug to monitor possible changes in thyroid hormone levels.

Jian-Pi-Yi-Shen formula ameliorates renal fibrosis-induced anemia in rats with chronic kidney disease.

ETHNOPHARMACOLOGICAL RELEVANCE: Jian-Pi-Yi-Shen (JPYS) formula is an effective herbal therapy against renal injury, and JPYS has been clinically applied to ameliorate chronic kidney disease (CKD) and CKD-associated anemia. Increasing evidence supports the link between renal fibrosis and anemia in CKD. JPYS possessed anti-fibrosis effects in experimental CKD. Nevertheless, research on the mechanisms of JPYS in ameliorating renal anemia (RA) through suppressing renal fibrosis remains to be clarified. AIM OF THE STUDY: Our study here was carried out to investigate the mechanisms of JPYS in protecting against RA. MATERIALS AND METHODS: An adenine-induced anemia model in rats with CKD at three different time points was established, and bio-samples taken from each group were analyzed. Biochemical analysis was employed to detect kidney function and hematological parameters. Masson staining was used to evaluate renal fibrosis of rats. Western blot and immunohistochemistry were utilized to evaluate the expressions of fibrotic markers, erythropoietin (EPO) and hypoxia inducible factor-2α (HIF-2α) in the kidneys of rats. Subsequently, transcriptomic analysis was conducted to disclose the possible mechanisms of JPYS in treating RA. Finally, the expression levels of key targets were analyzed and validated by using Western blot and enzyme-linked immunosorbent assay (ELISA). RESULTS: JPYS treatment improved kidney function, suppressed renal fibrosis and enhanced hematological parameters in CKD rats. Moreover, JPYS treatment restored the increased expression levels of fibrotic markers and the declined EPO with time dependence. In parallel, data indicated JPYS treatment stimulated the translocation of HIF-2α into nucleus in the renal interstitium and thus promoted the expression of EPO. Transcriptomic profiling disclosed that activations of both nuclear factor kappa B (NF-κB) and transforming growth factor-ß (TGF-ß)/Smad pathways were closely associated with RA. Ultimately, experimental validation results presented that the increased expressions of target proteins from the above-mentioned two pathways in the kidneys were decreased significantly after JPYS treatment. CONCLUSION: Our findings suggest that JPYS may improve RA by alleviating renal fibrosis, and the mechanisms of which involve in inhibiting the NF-κB and TGF-ß/Smad pathways.

Catalpol from Rehmannia glutinosa Targets Nrf2/NF-[Formula: see text]B Signaling Pathway to Improve Renal Anemia and Fibrosis.

Rehmannia glutinosa is widely recognized as a prominent medicinal herb employed by practitioners across various generations for the purpose of fortifying kidney yin. Within Rehmannia glutinosa, the compound known as catalpol (CAT) holds significant importance as a bioactive constituent. However, the protective effects of CAT on kidneys, including ameliorative effects on chronic kidney disease - most prominently renal anemia and renal fibrosis - have not been clearly defined. In this study, the kidney injury model of NRK-52E cells and C57BL/6N male mice was prepared by exposure to aristolochic acid I (AA-I), and it was discovered that CAT could ameliorate oxidative stress injury, inflammatory injury, apoptosis, renal anemia, renal fibrosis, and other renal injuries both in vivo and in vitro. Further treatment of NRK-52E cells with Nrf2 inhibitors (ML385) and activators (ML334), as well as NF-[Formula: see text]B inhibitors (PDTC), validated CAT's ability to target Nrf2 activation. Furthermore, the expression of phosphorylated NF-[Formula: see text]B p65, IL-6, and Cleaved-Caspase3 protein was inhibited. CAT also inhibited NF-[Formula: see text]B, and then inhibited the expression of IL-6, p-STAS3, TGF-[Formula: see text]1 protein. Therefore, CAT can regulate Nrf2/NF-[Formula: see text]B signaling pathway, significantly correct renal anemia and renal fibrosis, and is conducive to the preservation of renal structure and function, thus achieving a protective effect on the kidneys.

The Efficacy and Safety of Roxadustat for the Treatment of Posttransplantation Anemia: A Randomized Study.

Introduction: Roxadustat, an oral hypoxia-inducible factor prolyl hydroxylase (HIF-PH) inhibitor, can stimulate erythropoiesis. Our objective was to evaluate the efficacy and safety of roxadustat for the treatment of posttransplantation anemia (PTA). Methods: A total of 150 adult renal transplant recipients who underwent PTA were randomized to either the experimental group or the control group. During the 12-week randomized phase, the experimental group was randomized to oral iron and roxadustat treatment, and the control group was randomized to oral iron treatment only. The randomized phase was followed by a 12-week extended treatment period in which all participants were prescribed roxadustat treatment according to hemoglobin (Hb) levels. All the participants were followed-up with every 4 weeks. The primary end points were the change in Hb levels and response rate throughout the randomized period. Results: A total of 128 participants completed the randomized treatment period (90 in the experimental group and 38 in the control group). The mean Hb concentration at week 12 was 12.20 g/dl in the experimental group and 11.19 g/dl in the control group. A significantly higher proportion of participants who achieved Hb responses were in the experimental group than in the control group. Differences in serum iron, total iron-binding capacity (TIBC) and transferrin from baseline to week 8 to 12 were significant between the 2 groups. The adverse event profiles were comparable between the 2 groups. Conclusion: Roxadustat increased Hb in adult renal transplant recipients who underwent PTA, with an adverse event profile comparable to that of the control group.

Iron Deficiency in Newly Referred Patients With Chronic Renal Failure.

Addressing iron deficiency is the key to managing anemia in patients with chronic kidney disease (CKD). Erythropoiesis-stimulating agents (ESAs) and hypoxia-inducible factor prolyl-hydroxylase inhibitors (HIF-PHIs) are being prescribed to an increasing number of patients with CKD by primary physicians following the emergence of newer agents for the management of renal anemia. Among the 361 (average age: 76.8±12.1 years; 54.0% males) patients with stages 4 and 5 CKD newly referred to the nephrology department of our hospital between 2018 and 2023 who had evaluable transferrin saturation (TSAT) and ferritin levels, 169 patients (47%) had iron deficiency (ferritin <100 ng/mL or ferritin 100-300 ng/mL with TSAT <20%). The estimated glomerular filtration rate (eGFR), hemoglobin level, TSAT, and median ferritin level were 17.0±7.0 mL/min/1.73 m², 10.8±2.1 g/dL, 27.5±13.1%, and 130 ng/mL, respectively. ESAs, HIF-PHIs, and iron supplements were prescribed to 35 (9.7%), 17 (4.7%), and 35 (9.4%) patients, respectively. No significant differences were observed between the iron indices of the ESA group; however, the serum ferritin levels in the HIF-PHIs group were significantly lower than in those in the no-medication group (P=0.02). Multivariable logistic regression analysis revealed that age, female sex, eGFR, medications for renal anemia, and a history of ischemic heart disease were associated with iron deficiency (P<0.05). Although patients with renal failure tend to exhibit anemia, attention should be paid to iron deficiency anemia in addition to renal anemia, especially in patients with renal failure and a history of ischemic heart disease.

Roxadustat on Renal Anemia with Macroinflammation: A Retrospective Cohort Study.

Introduction: Roxadustat, the first-in-class drug for the treatment of renal anemia, has demonstrated efficacy in renal anemia with microinflammation. Additional data are needed regarding the efficacy of roxadustat on renal anemia with systemic macroinflammation. Methods: Three cohorts of renal anemia based on the basic level of high-sensitivity CRP were included. Patients with hsCRP ≤2 mg/L were selected as non-inflammation (NI) group; 2< hsCRP ≤10 mg/L as microinflammation (MI) group; hsCRP≥10 mg/L as macroinflammation (MA) group. Patients received oral roxadustat three times per week for 52 weeks. The primary end point was the hemoglobin level over weeks 12-52. The second end point was the cumulative proportion of patients achieving hemoglobin response by the end of week 12. Results: A total of 107 patients with chronic kidney diseases (CKDs) were enrolled. Overall, the baseline hemoglobin level of patients was 79.99 ± 11.20 g/L. Roxadustat could significantly increase the hemoglobin level in all of the three groups and did not show any significant difference (p > 0.05, respectively). Meanwhile, compared with that of the NI group, there was no significant difference in hemoglobin response rate in the MA group both at week 12 (p = 0.06; 95% confidence interval [CI], 0.9531-13.75) and week 52 (p = 0.37; 95% CI, 0.5080-7.937). Moreover, the hemoglobin response was independent of baseline hsCRP level (p = 0.72, 95% CI, -0.1139 to 0.0794). More importantly, roxadustat significantly reduced ferritin and serum iron levels and increased total iron-binding capacity in the three groups, which showed no significant differences among the three groups (p > 0.05, respectively). Conclusion: Roxadustat significantly improves anemia in CKD patients with systemic macroinflammation.

Crosstalk between oxygen signaling and iron metabolism in renal interstitial fibroblasts.

To maintain the oxygen supply, the production of red blood cells (erythrocytes) is promoted under low-oxygen conditions (hypoxia). Oxygen is carried by hemoglobin in erythrocytes, in which the majority of the essential element iron in the body is contained. Because iron metabolism is strictly controlled in a semi-closed recycling system to protect cells from oxidative stress caused by iron, hypoxia-inducible erythropoiesis is closely coordinated by regulatory systems that mobilize stored iron for hemoglobin synthesis. The erythroid growth factor erythropoietin (EPO) is mainly secreted by interstitial fibroblasts in the renal cortex, which are known as renal EPO-producing (REP) cells, and promotes erythropoiesis and iron mobilization. Intriguingly, EPO production is strongly induced by hypoxia through iron-dependent pathways in REP cells. Here, we summarize recent studies on the network mechanisms linking hypoxia-inducible EPO production, erythropoiesis and iron metabolism. Additionally, we introduce disease mechanisms related to disorders in the network mediated by REP cell functions. Furthermore, we propose future studies regarding the application of renal cells derived from the urine of kidney disease patients to investigate the molecular pathology of chronic kidney disease and develop precise and personalized medicine for kidney disease.

Effect of Jianpi Shengxue Tablet on Iron Metabolism and Nutritional Status in Patients with Renal Anemia: A Prospective, Randomized, Open, Parallel Controlled and Multicenter Clinical Study.

OBJECTIVE: This study aimed to analyze the clinical efficacy of the Jianpi Shengxue tablet for treating renal anemia. METHODS: A total of 200 patients with renal anemia from December 2020 to December 2022 were enrolled and randomly divided into two groups. Patients in the control group were treated with polysaccharide-iron complex, and those in the experimental group were administered Jianpi Shengxue tablet. After 8 weeks of continuous treatment, the therapeutic outcomes regarding anemia were compared between the two groups. RESULTS: After treatment, the red blood cell (RBC) count, hematocrit (HCT), reticulocyte percentage (RET), ferritin (SF), serum iron (SI), transferrin saturation (TSAT), and serum albumin (ALB) all increased (P<0.01), and the clinical symptom score and total iron binding capacity decreased (P<0.01) in the experimental group. Moreover, the improvements in RBC, HCT, RET, SF, SI, TAST, ALB, and clinical symptoms (fatigue, anorexia, dull skin complexion, numbness of hands and feet) in the experimental group were significantly greater than those in the control group (P<0.05). The total effective rate for treating renal anemia was significantly higher in the experimental group than in the control group (P<0.01). CONCLUSION: The Jianpi Shengxue tablet demonstrates efficacy in treating renal anemia, leading to significant improvements in the laboratory examination results and clinical symptoms of patients with renal anemia.

Discovery of DS44470011: An oral hypoxia-inducible factor prolyl hydroxylase inhibitor for the treatment of renal anemia.

Inhibition of the hypoxia-inducible factor prolyl hydroxylase (HIF-PHD) represents a promising strategy for discovering next-generation treatments for renal anemia. We identified a pyrimidine core with HIF-PHD inhibitory activity based on scaffold hopping of FG-2216 using crystal structures of HIF-PHD2 in complex with compound. By optimizing the substituents at the 2- and 6- positions of the pyrimidine core, we discovered DS44470011, which improves the effectiveness of erythropoietin (EPO) release in cells. Oral administration of DS44470011 to cynomolgus monkeys increased plasma EPO levels.

Ischemic Stroke During Daprodustat Therapy for Renal Anemia: A Report of Three Cases.

Hypoxia-inducible factor prolyl hydroxylase (HIF-PH) inhibitors are increasingly used to treat renal anemia. Ischemic stroke is a rare severe adverse event of HIF-PH inhibitor therapy, and its clinical characteristics have not been described to date. We report three cases of ischemic stroke during treatment with daprodustat, a HIF-PH inhibitor, for anemia associated with non-dialysis-dependent chronic kidney disease (CKD). In two patients, the hemoglobin level exceeded the target hemoglobin level of 13 g/dL for renal anemia. Two patients developed ischemic stroke within two months after the daprodustat administration. None of the three patients experienced a recurrence of ischemic stroke after daprodustat discontinuation. Daprodustat therapy is a risk factor for ischemic stroke, particularly during excessive elevation of hemoglobin levels or the early phases of treatment. Daprodustat should be discontinued to mitigate the risk of ischemic stroke recurrence.

The comparison of four hypoxia-inducible factor prolyl hydroxylase inhibitors on drug potency and cost for treatment in patients with renal anemia.

BACKGROUND: Five hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) have been approved for marketing in Japan. However, marked differences exist in terms of drug potency, dose requirement, and pharmacokinetics. METHODS: The primary evaluation in this study was the changes in hemoglobin levels, dose escalation, drug potency, and cost among HIF-PHIs, 3 months after the initiation of treatment. RESULTS: All patients treated with HIF-PHI between August 2020 and December 2023 were enrolled in this study. In total, 124 patients were administered daprodustat (N = 37), enarodustat (N = 44), molidustat (N = 13), or vadadustat (N = 30). The mean hemoglobin levels of daprodustat, enarodustat, molidustat, and vadadustat at 3 months were 11.7 g/dL, 11.8 g/dL, 12.2 g/dL, and 11.3 g/dL, respectively. At 3 months, the mean doses of daprodustat, enarodustat, molidustat, and vadadustat increased by 110%, 177%, 125%, and 152%, respectively, from the initial dose. The HIF-PHI potency indices (HPI) of daprodustat, enarodustat, molidustat, and vadadustat at 3 months were 0.168, 0.307, 0.184, and 0.254, respectively. At 3 months, the mean daily costs of daprodustat, enarodustat, molidustat, and vadadustat were JPY 345, JPY 434, JPY 206, and JPY 565, respectively. CONCLUSION: The difference in dose escalation for anemia treatment among HIF-PHIs is due to differences in drug potency, where the HPI significantly differs among HIF-PHIs. The disparity between the HPI and the cost of the initial dose accounts for the variance in the daily costs of renal anemia treatment among HIF-PHIs.

A Prospective Randomized Controlled Clinical Study to Investigate the Efficacy and Safety of Hypoxia-Inducible Factor-Prolyl Hydroxylase Inhibitors in Non-Dialysis Patients with Chronic Heart Failure and Renal Anemia Switched from Continuous Erythropoietin Receptor Activator Treatment.

Background/Objectives: Chronic kidney disease (CKD) and anemia are independent prognostic factors for heart failure. In recent years, hypoxia-inducible factor-prolyl hydroxylase (HIF-PH) inhibitors have become available for the treatment of renal anemia. This prospective randomized controlled study aimed to investigate the effects of switching from a continuous erythropoietin receptor activator (CERA) to one of four HIF-PH inhibitors in patients with chronic heart failure and renal anemia. Methods: Forty patients were randomized by the envelop method to receive treatment with roxadustat, daprodustat, vadadustat, or molidustat. The primary endpoint was the change in the hemoglobin (Hb) level. Secondary endpoints included changes in erythropoietin, changes in free T3, free T4, and thyroid-stimulating hormone (TSH), adverse effects, and drug dose increases and decreases. This study was preregistered in the University Hospital Medical Information Network Clinical Trials Registry (study ID: UMIN000041651). Results: We found no statistically significant difference between Hb levels with HIF-PH inhibitors and CERA, but at month 6, the Hb level was significantly higher with roxadustat than with vadadustat and daprodustat. Erythropoietin decreased significantly after switching to HIF-PH inhibitors. HIF-PH inhibitors had various significant effects on free T3, free T4, and TSH. No adverse events occurred. The doses of some drugs had to be increased or decreased. Conclusions: In patients with heart failure and renal anemia receiving CERA, Hb, NT-ProBNP, and renal function were similar after switching from CERA to HIF-PH inhibitors. The individual HIF-PH inhibitors appear to have different effects on anemia and thyroid function. However, because this was a single-center study with a limited sample size, the efficacy and potential limitations of HIF-PH inhibitors need to be further clarified.

The drug-specific properties of hypoxia-inducible factor-prolyl hydroxylase inhibitors in mice reveal a significant contribution of the kidney compared to the liver to erythropoietin induction.

AIMS: Kidney disease often leads to anemia due to a defect in the renal production of the erythroid growth factor erythropoietin (EPO), which is produced under the positive regulation of hypoxia-inducible transcription factors (HIFs). Chemical compounds that inhibit HIF-prolyl hydroxylases (HIF-PHs), which suppress HIFs, have been developed to reactivate renal EPO production in renal anemia patients. Currently, multiple HIF-PH inhibitors, in addition to conventional recombinant EPO reagents, are used for renal anemia treatment. This study aimed to elucidate the therapeutic mechanisms and drug-specific properties of HIF-PH inhibitors. METHODS AND KEY FINDINGS: Gene expression analyses and mass spectrometry revealed that HIF-PH inhibitors (daprodustat, enarodustat, molidustat, and vadadustat) alter Epo gene expression levels in the kidney and liver in a drug-specific manner, with different pharmacokinetics in the plasma and urine after oral administration to mice. The drug specificity revealed the dominant contribution of EPO induction in the kidneys rather than in the liver to plasma EPO levels after HIF-PH inhibitor administration. We also found that several HIF-PH inhibitors directly induce duodenal gene expression related to iron intake, while these drugs indirectly suppress hepatic hepcidin expression to mobilize stored iron for hemoglobin synthesis through induction of the EPO-erythroferrone axis. SIGNIFICANCE: Renal EPO induction is the major target of HIF-PH inhibitors for their therapeutic effects on erythropoiesis. Additionally, the drug-specific properties of HIF-PH inhibitors in EPO induction and iron metabolism have been shown in mice, providing useful information for selecting the proper HIF-PH inhibitor for each renal anemia patient.

A retrospective study on the efficacy of Roxadustat in peritoneal dialysis patients with erythropoietin hyporesponsiveness.

BACKGROUND/AIMS: Roxadustat, an oral medication for treating renal anemia, is a hypoxia-inducible factor prolyl hydroxylase inhibitor used for regulating iron metabolism and promoting erythropoiesis. To investigate the efficacy and safety of roxadustat in patients undergoing peritoneal dialysis (PD) with erythropoietin hyporesponsiveness. METHODS: Single-center, retrospective study, 81 PD patients (with erythropoietin hyporesponsiveness) were divided into the roxadustat group (n = 61) and erythropoiesis-stimulating agents (ESAs) group (n = 20). Hemoglobin (Hb), total cholesterol, intact parathyroid hormone (iPTH), brain natriuretic peptide (BNP), related indicators of cardiac function and high-sensitivity C-reactive protein (hs-CRP) were collected. Additionally, adverse events were also recorded. The follow-up period was 16 weeks. RESULTS: The two groups exhibited similar baseline demographic and clinical characteristics. At baseline, the roxadustat group had a mean Hb level of 89.8 ± 18.9 g/L, while the ESAs group had a mean Hb level of 95.2 ± 16.0 g/L. By week 16, the Hb levels had increased to 118 ± 19.8 g/L (p < 0.05) in the roxadustat group and 101 ± 19.3 g/L (p > 0.05) in the ESAs group. The efficacy of roxadustat in improving anemia was not influenced by baseline levels of hs-CRP and iPTH. Cholesterol was decreased in the roxadustat group without statin use. An increase in left ventricular ejection fraction and stabilization of BNP were observed in the roxadustat group. CONCLUSION: For PD patients with erythropoietin hyporesponsiveness, roxadustat can significantly improve renal anemia. The efficacy of roxadustat in improving renal anemia was not affected by baseline levels of hs-CRP0 and iPTH.

A nomogram for predicting the risk of treatment failure of roxadustat in peritoneal dialysis with renal anemia.

The determinants of roxadustat treatment failure in renal anemia remain elusive. This study sought to develop a nomogram for predicting the risk of treatment failure of roxadustat in peritoneal dialysis (PD) with renal anemia. A retrospective cohort analysis from January 1, 2019, to January 31, 2023, included 204 PD patients with renal anemia, stratified by attainment group (Hb ≥ 110 g/L, n = 103) or non-attainment (Hb < 110 g/L, n = 101) within 1 year treatment. Univariate and multivariate Cox proportional hazards regressions were employed to ascertain predictive factors and construct the nomogram. Nomogram efficacy was evaluated via C-index, time-dependent ROC, calibration plots, and decision curve analysis, with internal validation via tenfold cross-validation and 1000 bootstrap resampling iterations. The study identified PD duration, serum transferrin, cardiovascular comorbidities, and stains as significant predictors. The nomogram demonstrated moderate discrimination at 6 months (AUC: 0.717) and enhanced predictive accuracy at 12 months (AUC: 0.741). The predicted and actual risk probabilities were concordant, with clinical net benefits observed at six-month (8 to 53%) and twelve-month (27 to 84%) risk thresholds. This nomogram is a valuable tool for effectively predicting non-attainment risk and facilitating personalized management of renal anemia in PD patients treated with roxadustat.