EPO

Bodybuilding

Erythropoietin — a glycoprotein hormone naturally produced by peritubular cells in the kidneys that stimulates red blood cell production in bone marrow. FDA-approved for anemia associated with chronic kidney disease, chemotherapy, and surgical blood loss. Notorious for widespread abuse in endurance sports (cycling, distance running) due to its ability to dramatically increase oxygen-carrying capacity.

Half-Life

IV: 5 hours | Subcutaneous: 24 hours | Darbepoetin (long-acting): 48 hours

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Typical Dosage

Clinical (anemia): 50-300 IU/kg subcutaneous or IV three times weekly, titrated to target hemoglobin. Performance (illicit, dangerous): 50-200 IU/kg subcutaneous two or three times weekly. Must have regular hematocrit monitoring.

Administration

Subcutaneous or intravenous injection

Mechanism of Action

Erythropoietin is a 165-amino-acid glycoprotein hormone primarily produced by peritubular interstitial fibroblasts in the renal cortex in response to hypoxia (low oxygen levels). The oxygen-sensing mechanism is elegant: under normal oxygen conditions, prolyl hydroxylase domain (PHD) enzymes hydroxylate the transcription factor HIF-2α (hypoxia-inducible factor 2 alpha), marking it for ubiquitination by the von Hippel-Lindau (VHL) protein and proteasomal degradation. When oxygen drops, PHD activity decreases, HIF-2α accumulates, translocates to the nucleus, and drives EPO gene transcription.

Secreted EPO circulates to the bone marrow and binds to EPO receptors (EPOR) on erythroid progenitor cells — specifically colony-forming unit erythroid (CFU-E) cells and proerythroblasts. EPOR is a homodimeric cytokine receptor that activates JAK2 (Janus kinase 2) upon ligand binding. JAK2 phosphorylates the receptor and itself, creating docking sites for STAT5 (signal transducer and activator of transcription 5). Phosphorylated STAT5 dimerizes, enters the nucleus, and activates transcription of anti-apoptotic genes including Bcl-xL and Mcl-1. The primary effect is preventing the default apoptosis of erythroid progenitors — without EPO, approximately 90% of these cells undergo programmed cell death. EPO rescues them, allowing proliferation and differentiation through the reticulocyte stage into mature red blood cells.

The physiological result is increased red blood cell mass, hemoglobin concentration, and hematocrit — directly increasing the blood's oxygen-carrying capacity. Each red blood cell contains approximately 280 million hemoglobin molecules, each capable of binding four oxygen molecules. Even modest increases in hematocrit significantly improve oxygen delivery to tissues, which is why EPO abuse in endurance sports produces measurable performance gains. However, the same hematocrit elevation carries serious cardiovascular risks: blood viscosity increases exponentially above hematocrit values of 50%, dramatically increasing the risk of thrombosis, pulmonary embolism, stroke, and myocardial infarction. Several competitive cyclists died from EPO-related complications in the 1980s-90s, and WADA implemented hematocrit testing limits (initially 50%) before developing direct EPO detection assays.

Regulatory Status

FDA approved for anemia (Epogen, Procrit, Aranesp). Prescription required with REMS program. Banned by WADA. Black box warning for increased mortality in certain cancer patients.

Risks & Safety

Common: hypertension, headache, injection site pain, flu-like symptoms during initial treatment. Serious: polycythemia (dangerously elevated red blood cell count increasing blood viscosity), thromboembolism (stroke, heart attack, deep vein thrombosis, pulmonary embolism), pure red cell aplasia from anti-EPO antibodies. Rare: deaths reported in athletes from unmonitored use causing fatal blood viscosity. Multiple cyclist and endurance athlete deaths attributed to EPO abuse. Banned by WADA. FDA approved for specific anemias.

Research Papers

30
Intracellular Signaling Pathways for Erythropoietin-Induced Cell Proliferation in Primary Cultured Hepatocytes.

Published: February 11, 2026

Abstract

The mechanisms by which erythropoietin (EPO) promotes hepatocyte proliferation in primary cultures of adult rat hepatocytes were studied. EPO stimulated cell proliferation in a time- and dose-dependent manner, significantly increasing the number of hepatocyte nuclei and DNA synthesis. EPO-induced hepatocyte proliferation was completely suppressed by specific inhibitors targeting Janus kinase 2 (JAK 2), phospholipase C (PLC), protein kinase C (PKC), intracellular Ca2+ mobilization, mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) kinase (MEK), and mammalian target of rapamycin (mTOR). In contrast, inhibition of signal transducer and activator of transcription 3/5 (STAT 3/5) or granule secretion had no effect, indicating that EPO acts through a pathway distinct from the classical JAK2-STAT signaling pathway. Western blot analysis showed rapid phosphorylation of ERK 2, but not ERK 1, following EPO stimulation. In addition, EPO induced phosphorylation of PLC and C-rapidly accelerated fibrosarcoma (C-Raf), with PKC acting downstream of PLC and upstream of C-Raf. In contrast, intracellular Ca2+ concentration and activated Ras were transiently increased in hepatocytes after EPO stimulation, and EPO-induced activated Ras was significantly suppressed by the specific PKC inhibitor GF109203X. These results indicate that EPO engages the JAK2/PLC/PKC-Ca2+ signaling cascade, leading to the sequential activation of Ras, C-Raf, and ERK2, ultimately promoting hepatocyte proliferation in vitro.

Erythropoietic indices in asthma patients on controller medications: a comparative analysis.

Published: December 10, 2025

Abstract

A key feature of asthma is hypoxia, which triggers erythropoietin (EPO) production to stimulate erythropoiesis and compensate for oxygen deficits. This study investigates the impact of asthma controller medications on erythropoietic response by evaluating serum EPO levels and reticulocyte counts among asthma patients at Murtala Muhammad Specialist Hospital, Kano.

Phase-targeted erythropoietin derivatives for traumatic brain injury: bridging mechanisms to precision therapy.

Published: January 22, 2025

Abstract

Traumatic brain injury (TBI) unfolds through a well-defined chronology-hyperacute excitotoxic and inflammasome bursts, acute apoptotic and blood-brain-barrier failure, and subacute neurovascular remodeling-that no single-pathway drug can adequately cover. Recombinant erythropoietin (EPO) limits secondary damage in animals, yet its erythropoietic drive and thrombotic liability have stalled clinical adoption. This review integrates structural biology, pharmacology and translational data on four engineered EPO derivatives-carbamylated EPO, asialo-EPO, darbepoetin alfa and the helix-B surface peptide (HBSP/cibinetide)-that decouple cytoprotection from red-cell stimulation. We first outline how specific modifications (carbamylation, desialylation, hyper-glycosylation or helix truncation) bias EPOR signaling toward PI3K-AKT and away from JAK2-STAT5. We then match each derivative to its optimal injury window. Meta-analyses of randomized trials suggest a possible trend toward lower short-term mortality without a consistent functional benefit or thrombotic signal. By integrating molecular mechanisms, experimental findings, and early clinical observations, this review outlines hypotheses and future trial frameworks for phase-targeted, erythropoietin-based neuroprotection. Further controlled studies are required to establish safety, efficacy, and optimal therapeutic timing before translation to routine clinical use.

Non-hematopoietic erythropoietin splice variant is produced in the diseased human brain and confers neuroprotection.

Published: January 11, 2025

Abstract

Erythropoietin (EPO) is a pleiotropic cytokine with important functions in neuronal development and neuroprotection, but hematopoietic effects limit the therapeutic application of EPO in neurological diseases. We discovered human endogenous EPO splice variants that are non-hematopoietic but cytoprotective. Here, we demonstrate at the single-cell level that an alternative splice variant lacking exon 3 (hS3) is expressed in the human brain and is upregulated above EPO mRNA levels in ischemic and inflammatory neurological diseases. Conversely, hS3 mRNA expression is reduced below EPO levels in neurodegenerative disease. In an oxygen-glucose deprivation (OGD) model of ischemia, a single dose of cell-free synthesized constant glycosylated active hS3 protects neuronal cultures derived from human induced pluripotent stem cells (hiPSC) and human embryonic stem cells (hESC) more effectively than EPO. We identify the D-helix as a key functional domain of hS3 and demonstrate that the neuroprotective effect is enhanced by PD29, a novel small peptide derived from the D-helix of hS3. Long-term hS3 administration increases the neuroprotective effects in the OGD model by dose-dependent differential expression of apoptosis-related protein-coding genes and long non-coding RNAs (lncRNAs). In addition, our results suggest that hS3 induces early cell cycle inhibition without impairing differentiation of hiPSC and hESC into neuronal subtypes. In conclusion, EPO splice variant hS3 is part of the endogenous neuroprotective system in the human brain with significant therapeutic potential.

Diagnostic reassessment in myeloproliferative neoplasms: the value of functional iron parameters and JAK2 allelic burden.

Published: January 23, 2026

Abstract

Polycythemia vera (PV) and essential thrombocythemia (ET) are chronic myeloproliferative neoplasms (MPNs), often associated with mutations in JAK2, CALR, and MPL. Differentiating PV from ET can be challenging in borderline cases, particularly when hemoglobin (Hb), hematocrit (Hct) and erythropoietin (EPO) values are inconclusive. Functional iron parameters and JAK2 variant allele frequency (VAF) may provide additional discriminatory value. To assess the diagnostic utility of transferrin saturation index (TSI), serum ferritin, EPO, and JAK2 VAF in distinguishing PV from ET, and to evaluate their association with mutational profiles. We conducted a retrospective, single-center study including 260 adult patients diagnosed with PV or ET between 2009 and 2024. Demographic, clinical, molecular, and laboratory parameters-including ferritin, TSI, EPO, Hb, Hct, and JAK2 VAF-were analyzed. Comparative and correlation analyses were performed using appropriate statistical tests. Compared to ET, patients with PV had significantly lower ferritin (median: 35.65 vs. 95.05 ng/mL), TSI (12.9% vs. 21.64%), and EPO (2.23 vs. 6.11 mIU/mL), but higher Hb (17.7 vs. 14.3 g/dL) and Hct (54.6% vs. 43.0%) (all p < 0.001). TSI discriminated PV from ET better than ferritin (p < 0.001 vs. p = 0.128). Among JAK2-mutated cases, VAF was higher in PV than ET (median: 48% vs. 21%, p = 0.003). VAF correlated inversely with ferritin, TSI, and EPO, and positively with Hct. TSI and JAK2 VAF outperform ferritin as diagnostic markers to differentiate PV from ET. Integrating functional iron parameters with molecular data improves diagnostic accuracy, particularly in clinically ambiguous cases, and supports their inclusion in MPN diagnostic algorithms.

Tetravalent antibodies are more potent and efficacious erythropoiesis-stimulating agents than erythropoietin in vivo.

Published: February 7, 2026

Abstract

Recent studies have shown that tetravalent antibodies are potent and efficacious agonists of the erythropoietin (EPO) receptor (EPOR) both in vitro and in vivo. To identify antibody-based erythropoiesis-stimulating agents (ESAs) with therapeutic potential, we evaluated various tetravalent antibody formats for EPOR agonism and key biophysical properties necessary for biologic drug development. We identified two distinct tetravalent antibody formats that strongly stimulated the growth of UT7/Epo cells, which rely on EPOR signaling for proliferation. Moreover, one of these formats exhibited ideal biophysical characteristics for drug development. This format consisted of a diabody (Db) and two antigen-binding fragment (Fab) arms fused to the N- and C-termini of an Fc domain, respectively, to form a tetravalent Db-Fc-Fab (EPRA-0322). In a mouse model expressing the human EPOR, EPRA-0322 induced erythropoiesis with greater potency, efficacy, and duration than darbepoetin, a hyperglycosylated EPO currently used in clinical practice. These findings highlight tetravalent antibodies, and the Db-Fc-Fab format in particular, as promising next-generation ESAs suitable for large-scale production and clinical use.

LP-001, a Novel Long-Acting EPO-Fc Fusion Protein: A Phase I Dose-Escalation Study of Pharmacokinetics, Safety, and Tolerability in Healthy Chinese Subjects.

Published: January 18, 2026

Abstract

The objective of this study is to evaluate the safety, pharmacokinetics, and pharmacodynamics of LP-001 injection in healthy Chinese subjects. This was a single-center, double-blind, randomized, dose-escalation study. Fifty-six healthy adults were enrolled and randomly assigned to receive LP-001 or matched placebo. A total of 156.0 drug related adverse events occurred during treatment in 38 subjects who received LP-001 injection. The main events were grade 1 serum iron reduction and elevated triglycerides, which were considered related to the drug's erythropoietic effect and reversible. Pharmacokinetic exposure increased with dose (0.5-50 mcg·kg-1), but the increase in maximum plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC) was greater than the dose ratio (non-linear). Pharmacodynamics showed dose-dependent increases in hemoglobin (Hb), red blood cell count (RBC), hematocrit (HCT), and reticulocyte count (Rtc). The pharmacodynamic indicators in the 15 and 30 mcg·kg-1 multiple-dose groups were significantly higher than those in the placebo group, and the increase in RBC count was more pronounced in the 30 mcg·kg-1 group. LP001, a long-acting rhEPO, was safe and well-tolerated at all doses in this Phase I study. These findings support its continued development as a treatment for myelodysplastic syndromes (MDS).

Rapid quantitation of erythropoietin and identification of its glycans using membranes for capture and digestion.

Published: May 14, 2026

Abstract

Erythropoietin (EPO) is a glycoprotein hormone used to treat chronic anemia. Glycans at the three N-glycosylation sites strongly influence EPO's stability and bioactivity, so accurate quantitation of EPO and analysis of its glycosylation patterns are critical during production and subsequent processing. This work demonstrates a rapid workflow for EPO capture, quantitation, and glycan profiling. Newly developed porous membranes containing affinity peptides selectively capture EPO from cell culture supernatants. In a 96-well-plate format, captured EPO was labeled with a fluorescent antibody to enable quantitation in a 10-min assay with an average coefficient of variation of 12 %. Elution of captured EPO from a 2-cm glass-fiber membrane combined with tryptic membranes enabled efficient purification and digestion for liquid chromatography-tandem mass spectrometry (LC-MS/MS) glycan analysis. Without purification, conventional LC-MS/MS identification of EPO N-glycans in Chinese hamster ovary (CHO) cell supernatant was not possible. The rapid in-membrane digestion yielded glycan profiles comparable to those obtained from overnight in-solution digestion. Thus, the membrane-based assays provide a novel approach for rapid EPO quantitation and facilitating glycan identification.

FLIPs: Genetically encoded molecular biosensors for functional imaging of cell signaling by linear dichroism microscopy.

Published: January 15, 2026

Abstract

Genetically encoded fluorescent biosensors convert specific biomolecular events into optically detectable signals. However, imaging biomolecular processes often requires modifying the proteins involved, and many molecular processes are still to be imaged. Here, we present a biosensor design that uses a hitherto overlooked detection principle: directionality of optical properties of fluorescent proteins. The biosensors (termed FLIPs) offer an extremely simple design, high sensitivity, multiplexing capability, ratiometric readout, and other advantages, without requiring modifications to their targets. We demonstrate the sensor performance by real-time imaging activity of G protein-coupled receptors (GPCRs), G proteins, arrestins, and other membrane-associated proteins, as well as by identifying a previously undescribed, pronounced, endocytosis-associated conformational change in a GPCR-β-arrestin complex. In combination with an original tri-scanning linear dichroism confocal microscope, FLIPs allow unparalleled imaging of activity of nonmodified, endogenously expressed G proteins. Thus, FLIPs establish a powerful molecular platform for imaging cell signaling, allowing numerous future developments and insights.

Iron, the Essential Micronutrient: A Comprehensive Review of Regulatory Pathways of Iron Metabolism.

Published: December 27, 2025

Abstract

Iron constitutes an essential micronutrient in living organisms. All iron is absorbed into the body through dietary intake, except for exogenous therapeutic sources. Dietary iron is typically categorized as either heme or nonheme iron. Nonheme iron is essential for regulating iron in the body, as it exists in various forms, including soluble iron, storage iron within ferritin, and iron found in the catalytic centers of a wide range of proteins. Iron homeostasis is carefully managed to ensure that sufficient iron is available for critical biological processes while preventing the harmful effects that can arise from excess iron. The small peptide hormone hepcidin is the main regulator of iron homeostasis. Hepcidin and other iron regulatory molecules are regulated by various signaling pathways, such as IL-6/JAK-STAT, BMP/SMAD, and MAPK. Alterations in regulatory pathways may occur in response to iron accumulation or deficiency. Iron overload in the body can activate JAK/STAT, BMP/SMAD and MAPK pathways, leading to the initiation hepcidin synthesis. Conversely, in iron deficiency, as in hypoxic conditions or EPO-mediated signaling pathways, HAMP synthesis in the nucleus is reduced. Thus, this review provides an update on the possible regulatory pathways that play a role in iron regulation and may be potential therapeutic targets.

Clinical and laboratory predictors of recovery outcomes in isolated abducens nerve palsy.

Published: January 4, 2026

Abstract

To investigate the differences in clinical characteristics, laboratory parameters, and radiological findings between patients with complete and incomplete recovery of isolated abducens nerve palsy (IANP).

Erythropoietin Expression and Regulation: Piecing Together Known Mechanisms and Emerging Insights.

Published: March 2, 2026

Abstract

Erythropoietin (EPO) is a circulating glycoprotein hormone essential for red blood cell production. The history of EPO stretches from early observations of hypoxia in the mid-19th century to its gene cloning and the clinical use of recombinant forms. Structurally, EPO's extensive glycosylation shapes stability, receptor binding, and therapeutic potential, inspiring engineered analogs with distinct pharmacokinetics. Developmentally, EPO expression shifts from embryonic neural crest and fetal hepatocytes to renal interstitial fibroblasts after birth. EPO gene regulation integrates hypoxia-inducible factors, transcriptional repressors, enhancers, with HIF-2α as the principal activator, and post-translational mechanisms. Recent findings reveal genetic variants within the EPO gene in patients with erythrocytosis. Isoelectric focusing profiles of EPO in these patients was similar to the hepatic-derived EPO profiles in premature newborns, highlighting a dynamic and context-dependent regulation. These findings suggest that reactivation of EPO expression in the liver could be therapeutically valuable, given that hepatic-derived EPO exhibits enhanced activity. Clinically, erythropoiesis-stimulating agents transformed anemia management but raised safety concerns, leading to refined guidelines. The recent introduction of hypoxia-inducible factor prolyl hydroxylase inhibitors represents a new strategy that restores endogenous EPO production and coordinates iron metabolism through transient HIF stabilization. Outstanding challenges include the absence of faithful human EPO-producing cell models and incomplete understanding of the full molecular mechanisms controlling EPO expression and production. Combining insights from developmental biology, genetics, and epigenomics may open new avenues for therapies targeting disorders of erythropoiesis and oxygen homeostasis.

Fabrication and characterization of taste-masked core-shell nanofibre mats for dual drug delivery of antihypertensives in pediatrics.

Published: February 9, 2026

Abstract

Drug adherence in pediatrics can be challenging due to bitter drug taste, dysphagia and polypharmacy. With pediatric hypertension on the rise worldwide, this study investigated the use of electrospinning to create a novel taste-masked, fixed-dose combination of lisinopril dihydrate (LIS) and amlodipine besylate (AML) for paediatric use. Electrospun nanofibres of the antihypertensives were formulated as core-shell fibres with polyvinylpyrrolidone (PVP), and Eudragit® EPO (EEPO) by applying an electrical charge to a viscous mixture of the drugs, polymers and solvents. The drug loading, release kinetics, morphology, thermal analysis, physical and solid-state characterization of the fibre mats were evaluated. Taste-masking was investigated in vitro by electronic-tongue analysis. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses showed smooth, non-beaded core-shell fibres with diameters in the nanorange. Fourier transform infra-red (FTIR) spectroscopy and x-ray diffraction (XRD) studies confirmed the drugs were amorphously dispersed within the fibres and thermal analysis studies showed acceptable stability profile of the formulations. Both drugs were over 90 % released in 15 mins consistent with immediate release formulations. The e-tongue mean sensor response plot showed the nanofibre mats achieved a statistically significant enhanced taste-masking (p < 0.0001) compared to raw amlodipine which registered a high bitterness reading of 87 mV. This study therefore indicates that coaxial electrospinning may be used to produce a fixed-dose taste masked nanofibre mat of LIS and AML that can potentially be used to improve adherence in children.

Hydrolyzed Milk-Derived Peptides Promote Erythropoietin Pathways and Hematologic Recovery: A Cross-Species Analysis.

Published: December 10, 2025

Abstract

Anemia, characterized by reduced hemoglobin (Hb), remains a major health concern. Although iron and erythropoietin (EPO) therapies are effective, limitations in safety and accessibility have prompted interest in nutritional alternatives. Hydrolyzed milk-derived peptides (H-MDPs) contain bioactive sequences with diverse physiological effects, yet their role in erythropoiesis remains poorly defined. This study investigated the hematopoietic actions of H-MDP using zebrafish and mouse models. Adult zebrafish underwent phlebotomy-induced anemia and received oral H-MDP for 3 weeks. Hb levels, erythrocyte morphology, and expression of erythropoiesis- and iron-metabolism genes were assessed. In healthy mice, renal Epo expression, circulating EPO, and serum cytokines were measured after 2 weeks of H-MDP administration. H-MDP significantly accelerated Hb recovery in anemic zebrafish (4.6 ± 0.64 g/dL vs. 3.4 ± 0.66 g/dL in untreated fish at week 1) and markedly improved erythrocyte maturation. These effects coincided with strong induction of epo, hif1aa/b, igf1, csf1a, and csf3b in the heart and liver, as well as normalization of anemia-induced hepatic iron-transport genes (tfa, fpn1, tfr2) and reactivation of hamp. In mice, H-MDP elevated renal Epo mRNA and circulating EPO (approximately 2.3-fold) without altering steady-state Hb, and cytokine profiling with IPA-predicted activation of the erythropoietin signaling pathway. Collectively, these findings indicate that H-MDPs modulate erythropoiesis by coordinating the activation of EPO-related and iron-regulatory networks, supporting their potential as functional food ingredients for hematologic recovery and anemia management.

Adventitial fibroblast-derived NAMPT is associated with vascular remodeling in erythropoietin-induced abdominal aortic aneurysm.

Published: January 31, 2026

Abstract

Abdominal aortic aneurysm (AAA) remains a life-threatening condition with limited pharmacological interventions. While erythropoietin (EPO) has been implicated in AAA pathogenesis, its cell-type-specific effects on nicotinamide phosphoribosyltransferase (NAMPT)-mediated vascular remodeling remain unexplored. This study demonstrates that EPO administration in mice significantly induces AAA formation, characterized by aortic dilation, straightening of elastic laminae, and adventitial thickening. Through integrated in vivo and in vitro analyses, we identified that EPO differentially regulates NAMPT expression across vascular cell types: downregulating it in endothelial cells while robustly upregulating it in adventitial fibroblasts and infiltrating macrophages. Notably, EPO promoted proliferation of adventitial fibroblasts but suppressed endothelial cell growth. Mechanistically, the vascular adventitia emerged as the primary locus of NAMPT-driven pathology, where fibroblast-derived NAMPT creates a pro-inflammatory and pro-remodeling niche. These findings reveal a previously unrecognized role of adventitial fibroblasts in EPO-induced AAA through NAMPT dysregulation, suggesting novel therapeutic targets for AAA treatment. The study shifts therapeutic focus toward the adventitia as a key regulator of AAA progression.

Safety and efficacy of allogeneic umbilical cord blood cells and erythropoietin combination therapy in patients with subacute stroke.

Published: December 26, 2025

Abstract

Cell therapy has been proposed as a promising treatment for neurological recovery in patients with stroke. However, a strategy to enhance its efficacy is needed, as its clinical benefits have not yet been demonstrated in clinical trials. This study evaluated the efficacy of combination therapy using allogeneic umbilical cord blood (UCB), a relatively safe therapeutic cell source, and recombinant human erythropoietin (rhEPO) in patients with subacute stroke.

"Live high-train low" induced changes in hemoglobin mass and the erythropoietin-erythroferrone-hepcidin axis in female endurance athletes.

Published: December 1, 2025

Abstract

The effects of a 21-day live high-train low (LHTL) on hemoglobin mass (Hbmass) and iron demand including the erythropoietin (EPO)-erythroferrone (ERFE)-hepcidin axis and routine iron markers were investigated. Fifteen female endurance athletes completed either 21-day LHTL in normobaric hypoxia (2500 m, ~18 h·day-1) (INT, n = 8) or lived and trained in normoxia (CON, n = 7). Hbmass and resting blood were collected before and after the intervention. An additional blood sample was collected on Day 6 for INT. 21-day LHTL increased Hbmass 3.8% in INT (p < 0.001). EPO increased 35.6% from Day 0 to Day 6 in INT (p = 0.037) and then decreased 42.4% from Day 6 to Day 21 (p = 0.019). In INT, no changes were detected in ERFE or hepcidin, and from the routine iron markers only serum transferrin receptor increased from Day 0 to Day 21 (13.9%, p = 0.013). In CON, no changes were detected in Hbmass or iron markers. In INT, Hbmass and ferritin were positively associated (Day 0 to Day 6, p = 0.005). Thus, hepcidin and ERFE may not provide additional information regarding iron demand following 6- or 21-day LHTL compared to routine iron markers. The relationship between Hbmass and ferritin indicates that adequate ferritin levels are needed during hypoxia to support hematological adaptations.

Myomatous erythrocytosis syndrome with unusually normal serum erythropoietin levels.

Published: December 17, 2025

Abstract

Myoma uteri is the most common benign tumour in women, but myomatous erythrocytosis syndrome (MES) is rare. MES is characterised by erythrocytosis, a myomatous uterus and blood normalization after hysterectomy or myomectomy. It increases the risk of thromboembolic events, making early recognition crucial.A premenopausal, nulliparous woman in her 50s with dyslipidaemia and obesity presented with a 20-week-sized abdominopelvic mass but no abnormal uterine bleeding. CT imaging revealed a large right adnexal mass. Lab tests showed isolated erythrocytosis with normal tumour markers and serum erythropoietin (Epo). Hysterectomy and bilateral salpingo-oophorectomy confirmed multiple uterine myomas, the largest measuring 19.5 cm, along with a right ovarian haemorrhagic cyst. Postoperatively, her blood levels normalised, confirming MES.The exact mechanism remains unclear but may involve Epo production. While Epo is often linked to myomas, some cases, like ours, show normal levels, highlighting the need for further research to understand MES and develop targeted treatments.

Exploring the EPO/EPOR-βCR/TLR9 pathways in sepsis-associated encephalopathy: Therapeutic implications of EPO and HBSP.

Published: January 14, 2026

Abstract

Delirium is a prominent clinical manifestation of sepsis-associated encephalopathy (SAE) and is closely linked to increased mortality and adverse outcomes. Erythropoietin (EPO), traditionally used for treating anemia, is increasingly recognized for its non-hematopoietic tissue-protective effects. However, the relationship between EPO and the development of SAE, as well as the underlying mechanisms, remain unclear.

Increased levels of systemic iron content in adult-onset interleukin-6 knockout mice.

Published: December 15, 2026

Abstract

Interleukin-6 (IL-6) is a pleiotropic cytokine that participates in multiple metabolic disorders. IL-6 is well recognized to induce hepcidin expression and decreased serum iron through the JAK2/STAT3 pathway under inflammatory conditions. Targeted inhibition of IL-6 represents a potential therapeutic regimen for multiple diseases. The current study aimed to explore the physiological concentration of IL-6 in sustaining systemic iron homeostasis.

Vascularization potential of a dermal skin substitute material (Biodegradable Temporizing Matrix) by proangiogenic growth factors and ASC - an in ovo study.

Published: December 12, 2025

Abstract

In the treatment of severe burn injuries, autologous skin transplantation is increasingly being supplemented by synthetic dermis substitute materials. Novosorb® Biodegradable Temporizing Matrix (BTM) is a polyurethane foam used in a surgical procedure that currently requires a period of up to 21 days for successful neovascularization and integration, which is associated with a longer inpatient treatment. The objective of this study was to assess the efficacy of the growth factors EPO, FGF, PDGF, VEGF and adipogenic stem cells (ASC) in shortening the time required for BTM grafting and vascularization. BTM containing growth factor and/or ASC was grafted onto to the chorioallantoic membrane (CAM) in different configurations. The average vascular growth of the BTM in 9 different experimental groups was analyzed in comparison to the control group. After 7 days, the experiment was terminated, and the vascularization of the BTM was evaluated by macroscopic image analysis with ImageJ/Fiji, along with histological HE staining and immunohistochemical staining for vascular-specific factors. Successful grafting and vascularization of the BTM in ovo were achieved for the first time. The addition of growth factors and ASC increased the average vascularization of the BTM and the entire CAM. All experimental groups showed promising vascularization patterns, with the BTM + ASC and BTM + PDGF + ASC groups excelling. Differentiation of ASC was not induced in combination with BTM or growth factors. BTM vascularization is improved by proangiogenic growth factors and ASC, which can form the basis for clinical strategies aimed at shortening the inpatient treatment of severely burned patients.

IL-17 stimulates erythropoiesis in vivo by amplifying the response of erythroid progenitors to erythropoietin.

Published: December 10, 2025

Abstract

Red blood cell production is regulated by erythropoietin (Epo), maintaining tissue oxygen tension in the steady state and in response to stress. To date, only a handful of factors other than Epo are known to stimulate erythropoiesis, limiting therapeutic options. We recently found that IL-17, a pleiotropic pro-inflammatory cytokine, interacts synergistically with Epo to increase formation of erythroid colonies in vitro. Here, we administered IL-17 to mice to determine whether it accelerates erythropoiesis in vivo. We found that while IL-17 alone had little effect on erythroid and other hematopoietic lineages, combined treatment with both IL-17 and Epo generated a specific and strong synergistic response in erythroid progenitors that significantly increased erythropoietic rate. IL-17 administration also accelerated the erythropoietic response of mice to hypoxia. Single-cell transcriptomic analysis showed that IL-17 acts by sensitizing erythroid progenitors to Epo, rather than through a distinct transcriptional response. Using a dynamical model, we propose that this mechanism optimizes conflicting requirements in the regulation of erythropoiesis, balancing the need for low-cost maintenance of the steady state, with a sufficiently fast stress response. Further, our findings suggest a potentially broadly applicable mechanism whereby pleiotropic cytokines are able to exert lineage-specific effects when their actions are dependent on synergism with lineage-specific factors.

Erythropoietin receptor on cDC1s dictates immune tolerance.

Published: February 9, 2026

Abstract

Type 1 conventional dendritic cells (cDC1s) are unique in their efferocytosis1 and cross-presenting abilities2, resulting in antigen-specific T cell immunity3 or tolerance4-8. However, the mechanisms that underlie cDC1 tolerogenic function remain largely unknown. Here we show that the erythropoietin receptor (EPOR) acts as a critical switch that determines the tolerogenic function of cDC1s and the threshold of antigen-specific T cell responses. In total lymphoid irradiation-induced allograft tolerance9,10, cDC1s upregulate EPOR expression, and conditional knockout of EPOR in cDC1s diminishes antigen-specific induction and expansion of FOXP3+ regulatory T (Treg) cells, resulting in allograft rejection. Mechanistically, EPOR promotes efferocytosis-induced tolerogenic maturation7,11 of splenic cDC1s towards late-stage CCR7+ cDC1s characterized by increased expression of the integrin β8 gene12 (Itgb8), and conditional knockout of Itgb8 in cDC1s impairs tolerance induced by total lymphoid irradiation plus anti-thymocyte serum. Migratory cDC1s in peripheral lymph nodes preferentially express EPOR, and their FOXP3+ Treg cell-inducing capacity is enhanced by erythropoietin. Reciprocally, loss of EPOR enables immunogenic maturation of peripheral lymph node migratory and splenic CCR7+ cDC1s by upregulating genes involved in MHC class II- and class I-mediated antigen presentation, cross-presentation and costimulation. EPOR deficiency in cDC1s reduces tumour growth by enhancing anti-tumour T cell immunity, particularly increasing the generation of precursor exhausted tumour antigen-specific CD8+ T cells13 in tumour-draining lymph nodes and supporting their maintenance within tumours, while concurrently reducing intratumoural Treg cells. Targeting EPOR on cDC1s to induce or inhibit T cell immune tolerance could have potential for treating a variety of diseases.

Personalized CRISPR knock-in cytokine gene therapy to remodel the tumor microenvironment and enhance CAR T cell therapy in solid tumors.

Published: December 8, 2025

Abstract

The immunosuppressive tumour microenvironment (TME) remains a central barrier to effective immunotherapy in solid tumours. We present a gene-therapeutic strategy that enables localized remodelling of the TME via tumour-intrinsic cytokine expression. Central to this approach is CancerPAM, a multi-omics bioinformatics pipeline that identifies and ranks patient-specific, tumour-exclusive CRISPR-Cas9 knock-in sites with high specificity and integration efficiency. Using neuroblastoma as a model, CancerPAM analysis of tumour sequencing data identifies optimal knock-in sites for pro-inflammatory cytokines (CXCL10, CXCL11, IFNG), and CancerPAM rankings correlate strongly with target-site specificity and knock-in efficiency, validating its predictive performance. CRISPR-mediated CXCL10 knock-in enhances CAR T cell infiltration and antitumour efficacy in vitro and in vivo, including humanized CD34⁺ HuNOG mice, where CXCL10-expressing tumours show stronger immune infiltration and prolonged tumour control within a reconstituted human immune microenvironment. Our findings establish a framework for safe and effective CRISPR-based cytokine delivery, integrating localized TME remodelling with cellular immunotherapies to enhance CAR T cells and other treatments in immune-refractory solid tumours.

Food-derived chlorogenic acid prevents aortic aneurysm and dissection by nutritional restore branched-chain amino acid dyshomeostasis.

Published: April 5, 2026

Abstract

Aortic aneurysm and dissection (AAD) is a life-threatening cardiovascular disorder with no currently available targeted therapies, underscoring the critical need for effective preventive strategies. Through integrative analysis of the UK Biobank and FooDB databases, we identified chlorogenic acid (CGA)--a natural polyphenol abundant in coffee and tea--as a potential protective compound against AAD. Using two mouse models of AAD: β-aminopropionitrile (BAPN) plus angiotensin II (Ang II) in 4-week-old wild-type mice and erythropoietin (EPO)-induced AAD in 8-week-old wild-type mice, we demonstrated that CGA administration significantly reduced AAD incidence, mortality, and aortic wall damage. Mechanistically, we discovered that the large neutral amino acid transporter 3 (LAT3) plays a pivotal role in AAD pathogenesis by mediating excessive branched-chain amino acids (BCAAs) uptake into vascular smooth muscle cells (SMCs). Dysregulated BCAAs metabolism led to intracellular BCAAs accumulation and hyperactivation of the mTOR signaling pathway, driving SMCs reprogramming and promoting AAD development. Crucially, CGA directly targeted and inhibited LAT3, thereby normalizing BCAA metabolism and suppressing mTOR activity, which mitigated AAD progression. Our findings not only reveal the therapeutic potential of CGA in AAD prevention but also identify the LAT3/BCAA/mTOR axis as a novel mechanistic target for AAD intervention.

JAK2 wild-type erythrocytosis: concept, differential diagnosis, diagnostic steps, and treatment approaches.

Published: December 4, 2025

Abstract

JAK2 unmutated/wild-type erythrocytosis is a prevalent condition encompassing a wide spectrum of hereditary and acquired entities. It is conventionally defined by the same hemoglobin/hematocrit thresholds as for polycythemia vera. Incidence has been reported to be between 0.13% and 4.1%. The most clinically relevant step in the workup of erythrocytosis is the exclusion of polycythemia vera through JAK2 mutation screening. Consideration of relative polycythemia, normal outliers, and the influence of erythropoietic drugs and comorbidities is also imperative. Distinguishing long-standing from newly acquired erythrocytosis further streamlines the diagnostic process. Hereditary erythrocytosis (HE) is lifelong and typically associated with a positive family history. Subnormal serum erythropoietin (EPO) suggests an EPO receptor mutation. Otherwise, oxygen tension at 50% hemoglobin saturation (p50) discerns between high oxygen-affinity hemoglobin variants, 3-bisphosphoglycerate deficiency, methemoglobinemia, and PIEZO1 mutations (low p50) and germline oxygen-sensing pathway/other rare mutations (normal p50). Acquired erythrocytosis results from hypoxia-driven factors (eg, cardiopulmonary, altitude, renal artery stenosis) and other mechanisms of EPO overproduction (eg, EPO-secreting tumors) or hypersensitivity, as well as EPO-independent mechanisms. Drugs (eg, sodium glucose co-transporter-2 inhibitors, testosterone) are also common causes. Idiopathic erythrocytosis is a diagnosis of exclusion, increasingly attributed to underlying genetic mutations/polymorphisms. There are currently no evidence-based treatment guidelines. Low-dose aspirin and/or phlebotomy (with frequency determined by symptom relief) might be considered on an individualized basis in the presence of hyperviscosity symptoms, cardiovascular comorbidities, and/or a history of thrombosis. Aggressive control of cardiovascular risk factors is recommended in all. A graphic abstract representation is provided in Figure 1.

Determination of the role of aerobic and anaerobic training at different altitude on hypoxia-induced factor 1, hemoglobin, iron, erythropoietin, hepcidin, and nitric oxide.

Published: September 21, 2025

Abstract

Altitude training is a well-established strategy for improving athletic performance, particularly in endurance sports. Hypoxic exposure induces physiological adaptations through oxygen sensing and erythropoietic mechanisms. However, the comparative effects of aerobic and anaerobic training on hematological and biochemical markers under different altitude conditions have not yet been adequately investigated.

Investigation of peptides absorbed into blood of Colla Corii asini (E'jiao) based on cisplatin-induced anemia rat model and prediction of hematopoietic active peptide.

Published: February 28, 2026

Abstract

As a traditional medicine, Asini Corii Colla (E'jiao) demonstrates significant efficacy and a favorable safety profile in the treatment of Chemotherapy-induced anemia (CIA). However, its definitive hematopoietic constituents and pharmacodynamic mechanisms remain uncharacterized.

Erythropoietin as a multifaceted antiaging agent: Mechanisms and clinical potential.

Published: December 9, 2025

Abstract

Human aging is driven by several interconnected hallmarks, including genomic instability, mitochondrial dysfunction, and cellular senescence, which collectively underlie pathologies such as neurodegeneration and metabolic decline. Despite advances in identifying senescence-associated biomarkers and pathways, conventional antiaging compounds such as resveratrol and fisetin, lack regulatory approval owing to insufficient evidence from large-scale trials. Drug repurposing provides a cost-efficient strategy to target aging pathways by leveraging existing pharmacologic safety profiles. Erythropoietin (EPO) exemplifies this approach, demonstrating pleiotropic antiaging effects through modulation of cell survival pathways and tissue-protective mechanisms. Recent advancements in nonhematopoietic EPO derivatives, such as carbamylated EPO, further unlock its development potential by decoupling therapeutic benefits from erythropoietic activity. This review analyzes EPO molecular antiaging mechanisms and clinical applications in age-related diseases (2015-2025), focusing on multiorgan systemic effects and derivative development beyond anemia. SIGNIFICANCE STATEMENT: This review highlights erythropoietin (EPO) as a promising repurposed drug for combating aging, targeting hallmarks such as oxidative stress and cellular senescence. Crucially, nonhematopoietic EPO derivatives circumvent traditional safety risks while retaining multipathway protective effects in brain, cardiovascular, and metabolic tissues. By leveraging established pharmacology, EPO offers a cost-efficient strategy to advance aging interventions, addressing age-related pathologies beyond anemia.

Improvement of EPO Transgene Detection From Polymeric Dried Blood Spots for Antidoping Application.

Published: February 26, 2026

Abstract

For the past couple of years, black market products have appeared and were confirmed to contain genetic products coding for human erythropoietin (EPO). While being prohibited by the World Anti-Doping Agency (WADA), they could be used to produce endogenously more EPO hormone and hence increase performance. In a previous work, we demonstrated the potential of 20-μL dried blood spots (DBS) to detect the presence of EPO transgene in human blood down to 250 copies (12,500 copies/mL), despite lower sensitivity (30-fold) than in 1-mL fresh blood. As the use of DBS as a collection matrix for antidoping is going to expand in the near future, our aim was to develop and validate a new protocol to improve the sensitivity of gene doping detection from DBS. Three DBS devices were evaluated: polymeric Tasso-M20 (TASSO Inc.) and Mitra (Neoteryx), and cellulosic Protein Saver 903 (Whatman). The best results were achieved with polymeric DBS, and a full validation was performed for the detection of the EPO transgene using Tasso M-20 DBS; 1500 copies/mL were detected in 50% of cases and robust detection was obtained at 5000 copies/mL (100 copies transgene in 20-μL DBS) with the four spots of the Tasso device tested over several weeks. The results confirm that polymeric DBS can be used as an alternative to fresh blood for gene doping detection with high sensitivity simplifying also potential reanalysis in the future.

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