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 ◽  
...  

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.

2021 ◽  
Vol 8 (7) ◽  
pp. 123
Author(s):  
Ilaria Lippi ◽  
Francesca Perondi ◽  
George Lubas ◽  
Eleonora Gori ◽  
Alessio Pierini ◽  
...  

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.


2019 ◽  
Vol 1 (7) ◽  
pp. 105-108
Author(s):  
A. V. Sabirova ◽  
D. K. Volosnikov ◽  
O. V. Matyash

During Chronic Kidney Disease (CKD) development and progression emphasis is placed on structural-functional state of red blood cells. The aim of this paper is to examine red blood values and red blood cells morphological type in peripheral blood among children with CKD. 75 children with CKD aged 5-16 years were examined. The control group consisted of 25 healthy children of the same age range. Analysis of the morphometric parameters of red peripheral blood cells - mean volume (MCV) and erythrocyte diameter, mean content (MCH) and mean hemoglobin concentration in the erythrocyte (MCHC), were performed using a Gobas Micros (Roche) hematology counter. Smears were marked according to Romanovsky-Giemsa. Morphometric studies of red blood cells were carried out using the Morphology 5.2 program and red blood cell confocal microscopy on a LSM-710 Confocal Microscope, manufactured by Carl Zeiss. The tendency to poikilocytosis in CKD was confirmed. We identified that among children with CKD the distribution of red blood cells in diameter is disturbed, the content of microcytes increases, poikilocytosis is observed with an increase in the content of irreversibly transformed elements. The revealed features may serve as an additional criterion for the diagnosis of chronic kidney insufficiency at the early stage.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4748-4748
Author(s):  
Daniela Boehm ◽  
Mohamed Al-Rubeai ◽  
William G Murphy

Abstract Erythropoiesis is one of the body’s most productive cell production processes yielding 2×1011 new red cells from hematopoietic stem cells (HSCs) of the bone marrow every day. Intensive research has focused on mimicking this process ex vivo through application of various growth factor combinations or co-culture with stromal cells. To develop a scalable and reproducible system for large scale production of red blood cells we have investigated in vitro erythropoiesis of peripheral blood derived CD34+ cells with primary focus on the impact of the microenvironment on the process. The influence of cultivation conditions on expansion of erythroid progenitor cells and their terminal differentiation to mature red blood cells were studied in stroma-free liquid culture supplemented with stem cell factor (SCF), interleukin-3 (IL-3) and erythropoietin (EPO). Peripheral blood derived CD34+ cells were expanded by more than 105 fold over a 3 week period. This degree of expansion has only been achieved previously for CD34+ cells derived from more potent stem cell sources such as cord blood, bone marrow and G-CSF mobilized peripheral blood (Giarratana et al, Nat Biotechnol 2005). The natural environment of human erythropoiesis, the bone marrow, is a very crowded milieu where hematopoietic precursors and other cells are packed in close proximity. Cell crowdedness was found to have significant influences on ex vivo erythropoiesis. Cell density per surface area rather than cell concentration per media volume determined cell expansion during exponential growth where more crowded cells showed reduced overall expansion. In cultures inoculated at 4×105 cells/ml (2.1×105 cells/cm2) increasing cell density per area (i.e. decreasing surface area to volume ratio) 4fold (to 8.4×105 cells/cm2) resulted in 35±12% reduction of total expansion (p&lt;0.05, unpaired Student’s t-test). While 4fold increase of cell density in cultures seeded at 1×106 cells/ml (from 5.3×105 cells/cm2 to 2.1×106 cells/cm2) reduced overall expansion by 51±9% (p&lt;0.01). In late stage erythropoiesis, however, when cells had become arrested in G1 and no longer proliferated, cell density was seen to enhance cell viability. Dilution series of late stage erythroblasts showed that although cell viability gradually decreased over a 14 day cultivation period the decreasing rate was lower in cells cultivated at higher density as shown in the Figure. Enhanced viability in crowded culture conditions could reflect the cells’ dependency on direct cell-cell interactions as found in the marrow environment. Cultures grown to high cell densities of 2–3×106 cells/cm2 showed higher maturation efficiency than previously obtained in this cultivation set-up with more than 80% of cells being CD71-/GpA+. Enucleation yields of up to 45% were achieved indicating a significant amount of terminal maturation to red blood cells. Efficient maturation and particularly enucleation have in many cases been found to be dependent on or improved by interactions with feeder cells or macrophages (Fujimi et al, Int J Hematol 2008). Keeping erythroid cells at high densities during late stages of erythropoiesis possibly helps to mimic their in vivo environment, thus allowing for better survival and efficient terminal maturation without the need for co-culture with other cells. Figure Figure


2020 ◽  
Vol 21 (21) ◽  
pp. 8131
Author(s):  
Deepika Watts ◽  
Diana Gaete ◽  
Diego Rodriguez ◽  
David Hoogewijs ◽  
Martina Rauner ◽  
...  

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.


Author(s):  
Deepika Watts ◽  
Diana Gaete ◽  
Diego Rodriguez ◽  
David Hoogewijs ◽  
Martina Rauner ◽  
...  

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.


2018 ◽  
Vol 22 (4) ◽  
pp. 40-49 ◽  
Author(s):  
A. R. Volkova ◽  
O. D. Dygun ◽  
B. G. Lukichev ◽  
S. V. Dora ◽  
O. V. Galkina

Disturbance of the thyroid function is often detected in patients with different profiles. A special feature of patients with chronic kidney  disease is the higher incidence of various thyroid function  disturbances, especially hypothyroidism. It is known that in patients  with chronic kidney disease (CKD) iodine excretion from the body is  violated, since normally 90% of iodine is excreted in urine.  Accumulation of high concentrations of inorganic iodine leads to the  formation of the Wolf-Chaikoff effect: suppression of iodine  organization in the thyroid gland and disruption of the thyroid  hormones synthesis. Peripheral metabolism of thyroid hormones is  also disturbed, namely, deiodinase type I activity is suppressed and  peripheral conversion of T4 into T3 is inhibited (so-called low T3  syndrome). Therefore, patients with CKD are often diagnosed with  hypothyroidism, and the origin of hypothyroidism is not always  associated with the outcome of autoimmune thyroiditis. The article  presents an overview of a large number of population studies of  thyroid gland dysfunction in patients with CKD, as well as  experimental data specifying the pathogenetic mechanisms of  thyroid dysfunction in patients with CKD. Therapeutic tactics are still  not regulated. However, in a number of studies, replacement therapy with thyroid hormones in patients with CKD had some advantages.


2017 ◽  
Vol 96 (10) ◽  
pp. 1741-1747 ◽  
Author(s):  
Phatchanat Klaihmon ◽  
Sinmanus Vimonpatranon ◽  
Egarit Noulsri ◽  
Surapong Lertthammakiat ◽  
Usanarat Anurathapan ◽  
...  

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