scholarly journals Hypoxia Pathway Proteins are Master Regulators of Erythropoiesis

2020 ◽  
Author(s):  
Deepika Watts ◽  
Diana Gaete ◽  
Diego Rodriguez ◽  
David Hoogewijs ◽  
Martina Rauner ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Bone Marrow ◽  
Transcription Factor ◽  
Kidney Disease ◽  
Iron Metabolism ◽  
Blood Cells ◽  
Hypoxia Inducible Factor ◽  
Altered Expression ◽  
Master Regulators ◽  
Complex Process

Erythropoiesis is a complex process driving the production of red blood cells. During homeostasis, adult erythropoiesis takes place in the bone marrow and is tightly controlled by erythropoietin (EPO), a central hormone mainly produced in renal EPO-producing cells. The expression of EPO is strictly regulated by local changes in oxygen partial pressure (pO2) as under deprived oxygen (hypoxia) the transcription factor Hypoxia Inducible Factor-2 induces EPO. However, erythropoiesis regulation extends beyond the well-established HIF-EPO axis, and involves processes modulated by other hypoxia pathway proteins (HPPs), including proteins involved in iron metabolism. The importance of a number of these factors is evident as their altered expression has been associated with various anemia-related disorders, including chronic kidney disease. Eventually, our emerging understanding of HPPs and their regulatory feedback will be instrumental in developing specific therapies for anemic patients and beyond.

scholarly journals Hypoxia Pathway Proteins are Master Regulators of Erythropoiesis

2020 ◽  
Vol 21 (21) ◽  
pp. 8131
Author(s):  
Deepika Watts ◽  
Diana Gaete ◽  
Diego Rodriguez ◽  
David Hoogewijs ◽  
Martina Rauner ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Bone Marrow ◽  
Transcription Factor ◽  
Kidney Disease ◽  
Iron Metabolism ◽  
Blood Cells ◽  
Hypoxia Inducible Factor ◽  
Altered Expression ◽  
Master Regulators ◽  
Complex Process

Erythropoiesis is a complex process driving the production of red blood cells. During homeostasis, adult erythropoiesis takes place in the bone marrow and is tightly controlled by erythropoietin (EPO), a central hormone mainly produced in renal EPO-producing cells. The expression of EPO is strictly regulated by local changes in oxygen partial pressure (pO2) as under-deprived oxygen (hypoxia); the transcription factor hypoxia-inducible factor-2 induces EPO. However, erythropoiesis regulation extends beyond the well-established hypoxia-inducible factor (HIF)–EPO axis and involves processes modulated by other hypoxia pathway proteins (HPPs), including proteins involved in iron metabolism. The importance of a number of these factors is evident as their altered expression has been associated with various anemia-related disorders, including chronic kidney disease. Eventually, our emerging understanding of HPPs and their regulatory feedback will be instrumental in developing specific therapies for anemic patients and beyond.

ACE-536, a Modified Type II Activin Receptor Increases Red Blood Cells In Vivo by Promoting Maturation of Late Stage Erythroblasts

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4236-4236 ◽  
Author(s):  
Rajasekhar NVS Suragani ◽  
Samuel M. Cadena ◽  
Dianne Mitchell ◽  
Dianne Sako ◽  
Monique Davies ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Bone Marrow ◽  
Kidney Disease ◽  
Red Blood Cells ◽  
Late Stage ◽  
Blood Cells ◽  
Treated Group ◽  
Activin A ◽  
Vehicle Group ◽  
Type I

Abstract Abstract 4236 Anemia is one of the most common blood disorders in several diseases including cancer, heart failure, chronic kidney disease (CKD) and Myeloid Dysplastic Syndromes (MDS) associated with a negative outcome. Administration of recombinant Erythropoietin (EPO) represents the most common treatment for anemia. However, a significant number of people remain hypo or non-responsive to EPO treatment, and in some cases its use has been linked to tumor growth, cardiovascular disease and poorer survival. The members of TGFβ super family of ligands (Activins, GDFs and BMPs) and receptors (Type I and II) regulate more than 500 target genes transcriptionally by Smad phosphorylation and are involved in many cellular functions including cell growth, adhesion, migration, differentiation and apoptosis in a concentration and context dependent manner. Members of the TGFβ family have also demonstrated a role in erythropoiesis. ACE-536, a non-ESA agent is a soluble human Fc fusion chimera of a modified Activin Type IIb receptor with a mutation in its extracellular domain. Surface Plasmon Analysis (Biacore) analysis and cell based reporter assays revealed that this mutation disrupted its binding to Activin A but not to GDF11 or GDF8. ACE-536 acts as a decoy receptor for TGFβ signaling and demonstrated potent increase in red blood cells in all the tested animals (mice, rats and monkeys). Subcutaneous administration of ACE-536 (10mg/kg) to C57BL/6 mice resulted in a significant increase in hematocrit, hemoglobin and red blood cells (RBC) over the TBS treated vehicle group after 4 days. These observations were seen even in the presence of an EPO neutralizing antibody; suggesting that EPO is not directing the initial RBC response to ACE-536 treatment. There were no increase in BFU-E or CFU-E colony formation from bone marrow and spleen after 48hrs treatment with ACE-536 over TBS treated group demonstrating that it does not have effect on erythroid progenitor population. Differentiation profiling of bone marrow and splenic erythroblasts by flow cytometric analysis revealed that ACE-536 promotes maturation of developing erythroblasts. ACE-536 treatment for 72 hours resulted in a decrease in basophilic erythroblasts and an increase in late stage poly, ortho chromatophilic erythroblasts in bone marrow and spleen compared to the TBS treated mice. Treatment of Sprague-Dawley rats with a murine analogue of ACE-536 (RAP-536; 10mg/kg) increased the reticulocyte formation in peripheral blood over vehicle treated group. ACE-536 (10mg/kg) treatment combined with recombinant human EPO (1800 units/kg) for 72 hours increased RBC, hematocrit and hemoglobin by approximately 23% over TBS treated vehicle group and 12% over EPO treatment alone. Consistent with its role in proliferation, EPO increased splenic basophilic erythroblast formation. However, ACE-536 treatment combined with EPO significantly promoted maturation of late stage erythroblasts; demonstrating a novel mechanism during erythroid differentiation. To gain further insights into its mechanism of action, C57BL/6 mice were administered with or without RAP-536 (10mg/ml twice a week) pre treated for a week with neutralizing anti-Activin A (10mg/kg) or ActRIIa (10mg/ml) or ActRIIb (10mg/ml) (does not bind ACE-536) antibodies. Anti-ActRIIa but not anti-Activin A or anti- ActRIIb antibody pre-treatment inhibited the RBC increase by RAP-536 suggesting that ActRIIa or its ligands are necessary for transducing the signal. To summarize, ACE-536 treatment results in a rapid increase in red blood cells by a novel mechanism promoting maturation of late stage erythroblasts. The efficacy of ACE-536 molecule was tested in several acute and chronic anemia animal models including blood loss anemia, chemotherapy induced anemia, chronic kidney disease (5/6 Nephrectomy) and Myeloid Dysplastic Syndrome (MDS) and found that ACE-536 treatment prevents or decreases anemia in all these models. Furthermore, unlike EPO, ACE-536 did not promote tumor progression (in Lewis Lung Carcinoma model) thus offering strong promise as alternate treatments for anemia. Disclosures: Suragani: Acceleron Pharma: Employment. Cadena:Acceleron Pharma: Employment. Mitchell:Acceleron Pharma: Employment. Sako:Acceleron Pharma: Employment. Davies:Acceleron Pharma: Employment. Tomkinson:Acceleron Pharma: Employment. Devine:Acceleron Pharma: Employment. Ucran:Acceleron Pharma: Employment. Grinberg:Acceleron Pharma: Employment. Underwood:Acceleron Pharma: Employment. Pearsall:Acceleron Pharma: Employment. Seehra:Acceleron Pharma: Employment. Kumar:Acceleron Pharma: Employment.

MO560IS SERUM ERYTHROPOIETIN CORRELATED WITH IRON METABOLISM AND INFLAMMATION IN NON-DIALYSIS CHRONIC KIDNEY DISEASE PATIENTS WITH ANEMIA?

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Cristina-Stela Capusa ◽  
Ana-Maria Mehedinti ◽  
Ana Stanciu ◽  
Gabriela-Adriana Talimba ◽  
Liliana Viasu ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Bone Marrow ◽  
Kidney Disease ◽  
Serum Albumin ◽  
Serum Ferritin ◽  
Iron Metabolism ◽  
Mean Corpuscular Hemoglobin ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
Serum Hepcidin

Abstract Background and Aims Both the relative erythropoietin (Epo) deficiency and its relationship with serum hemoglobin (Hb) are widely postulated in chronic kidney disease (CKD), but the influence of chronic inflammation and iron status on serum Epo levels is still a matter of debate, with yet divergent reported results. Therefore, we aimed to assess the determinants of serum Epo in non-dialysis CKD patients. Method Fifty-two adults with CKD and anemia (defined as Hb <12g/dL), in stable clinical condition, never treated with erythropoiesis-stimulating agents (ESA) entered this cross-sectional, single-center study. Diabetes mellitus, active infectious and inflammatory diseases, malignancy, anemia of other causes than CKD, current immunosuppressive therapy, iron supplementation and blood transfusions in the previous six months were exclusion criteria. The subjects were mostly men (56%), elderly (two thirds over 60 years), with advanced CKD [71% in CKD stages G4-G5, median estimated glomerular filtration rate – eGFR 14.5 (95%CI 16 to 25) mL/min], moderate anemia [Hb 9.8 (95%CI 9.2 to 9.9) g/dL], and mild to moderate inflammation [C-reactive protein 6 (95%CI 9.2 to 18.4) mg/L]. Serum Epo was assessed by ELISA (Abcam® 119522). Complete blood count, reticulocyte index, peripheral blood smear, bone marrow aspiration (Perls’ stain), serum ferritin, and transferrin saturation, were used to investigate anemia and iron metabolism. Parameters of kidney disease (CKD etiology, eGFR and proteinuria), demographic data (age, gender), C-reactive protein, serum albumin, and serum hepcidin-25 (Hep-25, Bachem® commercial ELISA kit) were also analyzed. Results The median serum Epo of the whole cohort was 4.8 (95%CI 5.1 to 9.9) mU/mL. According to median Epo, subjects were clustered in Group 1 (below median, G1) and Group 2 (above median, G2). Estimated GFR and serum Hep-25 were lower in G1 than in G2 [10.6 (95%CI 9.7 to 20.8) vs. 26 (95%CI 19.1 to 32.8) mL/min, p=0.004, and 62.6 (95%CI 51.0 to 85.1) vs. 95.4 (95%CI 77.0 to 108.5) ng/mL, p=0.03, respectively]. All the other investigated parameters were similar in the two groups. In bivariate analysis (Spearman rank correlation), serum Epo was positively associated only with eGFR (rs=0.40, p=0.003). Marginal associations with the percentage of bone marrow sideroblasts, as marker of the iron available for erythropoiesis (rs=0.25, p=0.08), erythrocyte mean corpuscular hemoglobin concentration (rs=−0.26, p=0.07), and reticulocyte index (rs=0.24, p=0.09) were observed. Conversely, serum Epo was not related to hemoglobin, indices of iron stores (e.g. serum ferritin and iron content in bone marrow macrophages), inflammation and nutritional status (e.g. C-reactive protein and serum albumin). In a model of multiple linear regression which explained 14% of serum Epo variation, eGFR was the only determinant: Beta 0.14 (95%CI 0.05 to 0.23), p=0.004. Also, a binary logistic multiple regression model predicting serum Epo lower or higher than the median retained the eGFR as an independent predictor, while serum hepcidin showed only borderline significance: Conclusion Kidney function is the main determinant of endogenous erythropoietin level in moderately anemic patients with advanced CKD, ESA or iron naive, while serum hepcidin-25 seems to exert a limited influence.

scholarly journals Experimental modulation of Interleukin 1 shows its key role in chronic kidney disease progression and anemia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Inbar Bandach ◽  
Yael Segev ◽  
Daniel Landau
Keyword(s):  
Chronic Kidney Disease ◽  
Bone Marrow ◽  
Renal Function ◽  
Kidney Disease ◽  
Interleukin 1 ◽  
Hypoxia Inducible Factor ◽  
Lower Grade ◽  
Novel Treatments ◽  
Inflammatory Conditions ◽  
Kidney Disease Progression

AbstractInflammation in chronic kidney disease (CKD) is mostly due to activation of the innate immune system, in which Interleukin-1 (IL-1) is a key player. Anemia of CKD may also be due to erythropoietin (EPO) resistance, clinically associated with inflammation. IL-1 receptor antagonist knockout (RaKO) mice show arthritis and excessive inflammation. Inhibition of IL-1 was shown to be beneficial in many inflammatory conditions, but its role in CKD and anemia is unknown. Here, we report that enhanced inflammation in RaKO mice with CKD provoked both higher degrees of renal insufficiency and anemia in comparison to wild-type CKD, in association with a downregulation of renal hypoxia inducible factor-2 (HIF2) as well as decreased bone marrow EPO-receptor (EPOR) and transferrin receptor (TFR). In contrast, administration of P2D7KK, an anti-IL1b monoclonal antibody, to CKD mice results in a lower grade of systemic inflammation, better renal function and blunted anemia. The latter was associated with upregulation of renal HIF-2α, bone marrow EPO-R and TFR. Altogether, this supports the key role of inflammation, and IL-1 particularly, in CKD progression and anemia. Novel treatments to reduce inflammation through this and other pathways, may improve renal function, attenuate the anemic state or increase the response to exogenous EPO.

Deregulated iron metabolism in bone marrow from adenine-induced mouse model of chronic kidney disease

2018 ◽  
Vol 109 (1) ◽  
pp. 59-69
Author(s):  
Tomoko Kimura ◽  
Takahiro Kuragano ◽  
Kiyoko Yamamoto ◽  
Masayoshi Nanami ◽  
Yukiko Hasuike ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Bone Marrow ◽  
Kidney Disease ◽  
Mouse Model ◽  
Iron Metabolism

The problem with transferrin saturation as an indicator of iron ‘sufficiency’ in chronic kidney disease

2020 ◽  
Author(s):  
Anatole Besarab ◽  
Tilman B Drueke
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Iron Deficiency ◽  
Iron Metabolism ◽  
Iron Status ◽  
Hypoxia Inducible Factor ◽  
Transferrin Saturation ◽  
Deficiency Anemia ◽  
Iron Availability ◽  
Inflammatory State

Abstract After a brief review of physiological iron metabolism, we describe diagnostic tests for iron status and iron deficiency anemia in patients without chronic kidney disease (CKD) or inflammation. Thereafter we review the dysregulation of iron metabolism in CKD. Specific emphasis is placed on the role of the ‘inflammatory’ state that develops with the progression of CKD. It invokes changes in iron metabolism that are the exact opposite of those occurring during pure iron deficiency. As a result, transferrin saturation (TSAT) becomes a poorer index of iron availability to the bone marrow and serum ferritin no longer represents iron that can be used during erythropoiesis. We argue that serum iron may provide more information to guide iron therapy than TSAT. In other words, the emphasis on TSAT is misplaced. With the development of a number of hypoxia-inducible factor prolyl hydroxylase inhibitors, which restore iron metabolism toward the ‘physiologic state’, the iron indices indicating sufficient iron availability to avoid functional iron deficiency during therapy of CKD-associated anemia are likely to change. We summarize these changes in the section ‘A peek into things to come!’, citing the available data.

scholarly journals Safety and Efficacy of Roxadustat for Anemia in Patients With Chronic Kidney Disease: A Meta-Analysis and Trial Sequential Analysis

2021 ◽  
Vol 8 ◽  
Author(s):  
Chao Liu ◽  
Zhangning Fu ◽  
Jiawei Jiang ◽  
Kun Chi ◽  
Xiaodong Geng ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Iron Metabolism ◽  
Sequential Analysis ◽  
Meta Analysis ◽  
Hypoxia Inducible Factor ◽  
Trial Sequential Analysis ◽  
Controlled Trials ◽  
Cochrane Central Register ◽  
Safety And Efficacy

Background: Roxadustat, a hypoxia-inducible factor prolyl-hydroxylase inhibitor (HIF-PHI), has been used to treat anemia in patients with chronic kidney disease (CKD). However, its safety and efficacy remain controversial.Methods: The PubMed, EMBASE, Science Citation Index, Cochrane Central Register of Controlled Trials, and Clinical Trial Registries databases were searched for relevant studies published up to April 2021. We identified randomized controlled trials (RCTs) comparing roxadustat with placebo or erythropoiesis-stimulating agents (ESAs) in anemia patients with CKD with or without dialysis.Results: Eleven studies including 6,631 patients met the inclusion criteria. In non-dialysis-dependent (NDD-) and dialysis-dependent (DD-) CKD patients, the total adverse events were not significantly different between the roxadustat and control (placebo for NDD-CKD patients and ESA for DD-CKD patients) groups [relative risk (RR) = 1.02, 95% confidence interval (CI) = 1.00, 1.04, P = 0.08, and RR = 1.22, 95% CI = 0.91, 1.64, P = 0.18, respectively], and the trial sequential analysis (TSA) confirmed the result in the NDD-CKD groups. No significant differences in hyperkalemia and infection incidences were found between roxadustat and placebo in the DD-CKD groups. The pooled results showed that roxadustat significantly increased the hemoglobin response rate compared with placebo in the NDD-CKD group and had an effect similar to that of ESA in the DD-CKD group. However, iron metabolism parameters did not seem to be obviously optimized by roxadustat.Conclusion: Roxadustat can be safely used in CKD patients. Oral roxadustat was more effective than placebo as a therapy for anemia in NDD-CKD patients and non-inferior to ESA in correcting anemia in DD-CKD patients. However, additional clinical trials are still needed to further prove whether roxadustat can optimize iron metabolism.

scholarly journals Erythrogram Patterns in Dogs with Chronic Kidney Disease

2021 ◽  
Vol 8 (7) ◽  
pp. 123
Author(s):  
Ilaria Lippi ◽  
Francesca Perondi ◽  
George Lubas ◽  
Eleonora Gori ◽  
Alessio Pierini ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Common Finding ◽  
Severe Condition ◽  
Regeneration Rate ◽  
Morphological Abnormalities ◽  
Morphological Alterations ◽  
Frequent Finding

Anemia is considered a common finding in dogs with chronic kidney disease (CKD), typically as normochromic, normocytic, and non-regenerative. Although anemia can occur at any CKD IRIS (International Renal Interest Society) stage, its severity is related with the loss of kidney function. The aim of the present study was to retrospectively evaluate quantitative and morphological abnormalities of the erythrogram in dogs at different CKD IRIS stages. A total of 482 CBCs from 3648 initially screened were included in the study. Anemia was present in 302/482 (63%) dogs, in the majority of which it was normochromic, normocytic, and non-regenerative (295/302; 98%). The number of reticulocytes was <60,000/μL in the majority of dogs (248/295; 84%), with a correlation between poor regeneration rate and progression of CKD (p = 0.0001). The frequency of anemia significantly differed (p = 0.0001) among the IRIS stages: 108/231 (47%) in IRIS 2, 77/109 (71%) in IRIS 3, and 117/142 (82%) in IRIS 4. Dogs at IRIS stages 3 and 4 were more likely to have moderate to severe anemia, compared to dogs at IRIS stage 2 (p = 0.0001). Anisocytosis was the most frequent morphological abnormality (291/482; 60%), whereas the presence of poikilocytosis showed an association with progression of IRIS stages (p = 0.009). Among different morphological abnormalities, the frequency of fragmented red blood cells and Howell–Jolly bodies showed a significant association with the progression of CKD. Anemia was a frequent finding in CKD dogs, mostly associated with none to poor regeneration rate. Similar to human medicine, advanced CKD stages are more frequently characterized by morphological alterations, such as fragmented red blood cells and Howell–Jolly bodies, which may suggest a more severe condition of reduced bone marrow activity and microangiopathy.

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