Distribution of serum erythropoietin levels in Japanese patients with myelodysplastic syndromes

Serum Erythropoietin level in anemia of elderly with unclear etiology

Anemia is a common condition, but its causes are often unclear, especially in elderly adults. Erythropoietin (EPO) levels are known to be elevated in myelodysplastic syndrome and hematologic malignancies, but decreased in chronic benign anemia. This study aimed to investigate whether EPO levels could be used to identify underlying bone marrow diseases including malignancies, among elderly anemic patients with unclear etiology. This single centered retrospective study included patients presented with isolated anemia and had their EPO levels measured at their first visit. Patients were divided into two groups: bone marrow disease and benign etiologic anemia, based on observation and bone marrow test results. Out of 1180 patients reviewed, 81 patients with anemia of unclear etiology were identified, including 67 with benign anemia and 14 with bone marrow disease. Statistically significant difference in EPO levels between these two groups (P < 0.001) were observed. The receiver operating characteristic curve analysis showed that an EPO cut-off value of 36.4 mU/mL had a sensitivity and specificity of 92.8% and 94.0% for detecting underlying bone marrow disease, respectively. We suggest measuring serum EPO levels can aid in the early detection of benign anemia from bone marrow disease, including malignancies, with high sensitivity and specificity.

The prognostic value of serum erythropoietin in patients with lower-risk myelodysplastic syndromes: a review of the literature and expert opinion

Myelodysplastic syndromes (MDS) are hematopoietic stem cell malignancies associated with an erythroid maturation defect, resulting in anemia. Treatments for MDS include erythropoiesis-stimulating agents (ESAs). The identification of prognostic markers is important to help predict response and improve outcomes. Various scoring systems have been developed to help predict response to ESAs. Despite limitations in its assessment, serum erythropoietin (sEPO) level is an important predictor of hematologic response to ESAs in patients with lower-risk MDS. Numerous studies have reported significantly lower sEPO levels among responders versus non-responders. Furthermore, treatment response is significantly more likely among those with sEPO levels below versus those above various cutoffs. Other prognostic indicators for response to ESAs include lower transfusion requirement, fewer bone marrow blasts, higher hemoglobin, lower serum ferritin, lower-risk MDS, and more normal cytogenetics. Studies of other MDS therapies (e.g., lenalidomide and luspatercept) have also reported that lower sEPO levels are indicative of hematologic response. In addition, lower sEPO levels (up to 500 IU/L) have been included in treatment algorithms for patients with lower-risk MDS to define whether ESAs are indicated. Lower sEPO levels are predictive of hematologic response—particularly to ESAs. Further, clinical trials should use sEPO thresholds to ensure more homogeneous cohorts.

Erythropoietin inhibits osteoblast function in myelodysplastic syndromes via the canonical Wnt pathway

The effects of erythropoietin on osteoblasts and bone formation are controversial. Since patients with myelodysplastic syndromes often display excessively high erythropoietin levels, we aimed to analyze the effect of erythropoietin on osteoblast function in myelodysplastic syndromes and define the role of Wnt signaling in this process. Expression of osteoblast-specific genes and subsequent osteoblast mineralization was increased in mesenchymal stromal cells from healthy young donors by in vitro erythropoietin treatment. However, erythropoietin failed to increase osteoblast mineralization in old healthy donors and in patients with myelodysplasia, whereas the basal differentiation potential of the latter was already significantly reduced compared to that of age-matched controls (P<0.01). This was accompanied by a significantly reduced expression of genes of the canonical Wnt pathway. Treatment of these cells with erythropoietin further inhibited the canonical Wnt pathway. Exposure of murine cells (C2C12) to erythropoietin also produced a dose-dependent inhibition of TCF/LEF promoter activity (maximum at 500 IU/mL, −2.8-fold; P<0.01). The decreased differentiation capacity of erythropoietin-pretreated mesenchymal stromal cells from patients with myelodysplasia could be restored by activating the Wnt pathway using lithium chloride or parathyroid hormone. Its hematopoiesis-supporting capacity was reduced, while reactivation of the canonical Wnt pathway in mesenchymal stromal cells could reverse this effect. Thus, these data demonstrate that erythropoietin modulates components of the osteo-hematopoietic niche in a context-dependent manner being anabolic in young, but catabolic in mature bone cells. Targeting the Wnt pathway in patients with myelodysplastic syndromes may be an appealing strategy to promote the functional capacity of the osteo-hematopoietic niche.