New Insights Into Erythropoietin and Epoetin Alfa: Mechanisms of Action, Target Tissues, and Clinical Applications

Neonatal encephalopathy due to suspected hypoxic ischemic encephalopathy: pathophysiology, current, and emerging treatments

BACKGROUND

Neonatal encephalopathy (NE) due to suspected hypoxic-ischemic encephalopathy (HIE), referred to as NESHIE, is a clinical diagnosis in late preterm and term newborns. It occurs as a result of impaired cerebral blood flow and oxygen delivery during the peripartum period and is used until other causes of NE have been discounted and HIE is confirmed. Therapeutic hypothermia (TH) is the only evidence-based and clinically approved treatment modality for HIE. However, the limited efficacy and uncertain benefits of TH in some low- to middle-income countries (LMICs) and the associated need for intensive monitoring have prompted investigations into more accessible and effective stand-alone or additive treatment options.

DATA SOURCES

This review describes the rationale and current evidence for alternative treatments in the context of the pathophysiology of HIE based on literatures from Pubmed and other online sources of published data.

RESULTS

The underlining mechanisms of neurotoxic effect, current clinically approved treatment, various categories of emerging treatments and clinical trials for NE are summarized in this review. Melatonin, caffeine citrate, autologous cord blood stem cells, Epoetin alfa and Allopurinal are being tested as potential neuroprotective agents currently.

CONCLUSION

This review describes the rationale and current evidence for alternative treatments in the context of the pathophysiology of HIE. Neuroprotective agents are currently only being investigated in high- and middle-income settings. Results from these trials will need to be interpreted and validated in LMIC settings. The focus of future research should therefore be on the development of inexpensive, accessible monotherapies and should include LMICs, where the highest burden of NESHIE exists.

Exploring glycans as vital biological macromolecules: A comprehensive review of advancements in biomedical frontiers

This comprehensive review delves into the intricate landscape of glycans and glycoconjugates, unraveling their multifaceted roles across diverse biological dimensions. From influencing fundamental cellular processes such as signaling, recognition, and adhesion to exerting profound effects at the molecular and genetic levels, these complex carbohydrate structures emerge as linchpins in cellular functions and interactions. The structural diversity of glycoconjugates, which can be specifically classified into glycoproteins, glycolipids, and proteoglycans, underscores their importance in shaping the architecture of cells. Beyond their structural roles, these molecules also play key functions in facilitating cellular communication and modulating recognition mechanisms. Further, glycans and glycoconjugates prove invaluable as biomarkers in disease diagnostics, particularly in cancer, where aberrant glycosylation patterns offer critical diagnostic cues. Furthermore, the review explores their promising therapeutic applications, ranging from the development of glycan-based nanomaterials for precise drug delivery to innovative interventions in cancer treatment. This review endeavors to comprehensively explore the intricate functions of glycans and glycoconjugates, with the primary goal of offering valuable insights into their extensive implications in both health and disease. Encompassing a broad spectrum of biological processes, the focus of the review aims to provide a comprehensive understanding of the significant roles played by glycans and glycoconjugates.

Bilateral, sequential orbital inflammatory syndrome associated with ruxolitinib

Ruxolitinib is an oral Janus associated kinase (JAK) inhibitor commonly used in the treatment of primary myelofibrosis. We describe a case of an 86-year-old woman on ruxolitinib for primary myelofibrosis who presented with a three-day history of worsening left eyelid swelling, pain, and decreased vision. Her exam was notable for left upper lid ptosis, periorbital edema, and nearly complete external ophthalmoplegia along with diffuse conjunctival injection and microcystic corneal edema. An orbital computed tomography demonstrated left proptosis accompanied by extensive inflammatory changes of the preseptal and orbital soft tissues. She was diagnosed with acute left orbital inflammatory syndrome (OIS) and treated with intravenous methylprednisolone, one gram over 48 hours followed by an oral steroid taper as well as discontinuation of her ruxolitinib. Complete recovery was noted at her one-week follow-up visit and ruxolitinib was restarted. However, 3 weeks later, she presented with new right periorbital swelling and pain and was found to have a sequential right OIS for which she was again treated with methylprednisolone and discontinuation of ruxolitinib with the goal of transitioning to an alternative biologic agent. Although there are no previous documented cases of ruxolitinib associated orbital inflammatory syndrome, a similar JAK inhibitor medication, Fedratinib, has been reported to cause a similar side effect. We propose that her ruxolitinib paradoxically lead to a pro-inflammatory state leading to bilateral, sequential orbital inflammatory syndrome.

Single-and repeat-dose toxicity of HM10760A, a long-acting erythropoietin, in rats and monkeys

Anemia is a frequent complication of chronic kidney disease (CKD) that causes an increase in morbidity and mortality and accelerates the rate of disease progression. Treatment with recombinant human erythropoietin (rhEPO) is a major breakthrough in the therapy of renal anemia. HM10760A, a long-acting EPO, has been developed as a treatment for anemia in CKD patients. A series of preclinical toxicology studies, such as acute, 4 week repeat-dose, and 13 week repeat-dose, was completed to support the safety of human exposure to HM10760A for up to 13 weeks. The rodent and non-rodent species used in the pivotal preclinical general toxicity studies were rats and monkeys, respectively. A once-a-week or once-every-two-week i.v dosing regimen was applied for 4 week and 13 week repeat-dose toxicity studies, respectively, in consideration of the expected administration frequency in humans. Based on the 13 week repeat-dose toxicity studies, 2.61 μg/kg and 22.03 μg/kg can be considered as the NOAELs (no observed adverse effect levels) in rats and monkeys, respectively. Almost all observations recorded at the low- and mid-dose levels are typical pharmacological effects of EPO and not uniquely attributed HM10760A toxicity. To account for the differences between human being and animal physiologies, the safety of HM10760A needs to be further confirmed in future clinical studies.

[A multicenter investigation and analysis on anemia in lymphoma patients in Shanghai]

目的

研究淋巴瘤患者贫血的发生情况、影响因素及其对疗效的影响。

方法

对上海地区4所综合性医院2017年1月至2018年6月住院的501例淋巴瘤患者进行6个月随访，统计分析贫血相关临床资料。

结果

501例淋巴瘤患者中178例（35.5%）伴有贫血；初治淋巴瘤289例，其中贫血患者99例（34.3%）；调查过程中新发贫血136例（42.1%）；整个调查过程，贫血患病率达62.7%。单因素分析结果显示：初治淋巴瘤患者贫血发生与年龄、病理类型、有无骨髓浸润、国际预后指数（IPI）评分及Ann Arbor分期相关；初治淋巴瘤伴有贫血的患者较无贫血患者疗效差。多因素分析结果显示：IPI评分3~5分（P<0.001，OR=4.230，95%CI 2.339~7.650）及化疗（P<0.001，OR=11.049，95%CI 5.149~23.711）是新发贫血的独立危险因素，患者的体能状态评分（PS评分）与贫血显著相关。

结论

淋巴瘤患者贫血发病率及患病率高，贫血的发生与严重程度与淋巴瘤患者疗效及体能状态密切相关。

Chemotherapy-related cognitive impairment in older patients with cancer

Chemotherapy-related cognitive impairment (CRCI) can occur during or after chemotherapy and represents a concern for many patients with cancer. Among older patients with cancer, in whom there is little clinical trial evidence examining side effects like CRCI, many unanswered questions remain regarding risk for and resulting adverse outcomes from CRCI. Given the rising incidence of cancer with age, CRCI is of particular concern for older patients with cancer who receive treatment. Therefore, research related to CRCI in older patients with cancers is a high priority. In this manuscript, we discuss current gaps in research highlighting the lack of clinical studies of CRCI in older adults, the complex mechanisms of CRCI, and the challenges in measuring cognitive impairment in older patients with cancer. Although we focus on CRCI, we also discuss cognitive impairment related to cancer itself and other treatment modalities. We highlight several research priorities to improve the study of CRCI in older patients with cancer.

Longer-term outcomes of darbepoetin alfa versus epoetin alfa in patients with ESRD initiating hemodialysis: a quasi-experimental cohort study

BACKGROUND

Adequately powered studies directly comparing hard clinical outcomes of darbepoetin alfa (DPO) versus epoetin alfa (EPO) in patients undergoing dialysis are lacking.

STUDY DESIGN

Observational, registry-based, retrospective cohort study; we mimicked a cluster-randomized trial by comparing mortality and cardiovascular events in US patients initiating hemodialysis therapy in facilities (almost) exclusively using DPO versus EPO.

SETTING & PARTICIPANTS

Nonchain US hemodialysis facilities; each facility switching from EPO to DPO (2003-2010) was matched for location, profit status, and facility type with one EPO facility. Patients subsequently initiating hemodialysis therapy in these facilities were assigned their facility-level exposure.

INTERVENTION

DPO versus EPO.

OUTCOMES

All-cause mortality, cardiovascular mortality; composite of cardiovascular death, nonfatal myocardial infarction (MI), and nonfatal stroke.

MEASUREMENTS

Unadjusted and adjusted HRs from Cox proportional hazards regression models.

RESULTS

Of 508 dialysis facilities that switched to DPO, 492 were matched with a similar EPO facility; 19,932 (DPO: 9,465 [47.5%]; EPO: 10,467 [52.5%]) incident hemodialysis patients were followed up for 21,918 person-years during which 5,550 deaths occurred. Almost all baseline characteristics were tightly balanced. The demographics-adjusted mortality HR for DPO (vs EPO) was 1.06 (95% CI, 1.00-1.13) and was materially unchanged after adjustment for all other baseline characteristics (HR, 1.05; 95% CI, 0.99-1.12). Cardiovascular mortality did not differ between groups (HR, 1.05; 95% CI, 0.94-1.16). Nonfatal outcomes were evaluated among 9,455 patients with fee-for-service Medicare: 4,542 (48.0%) in DPO and 4,913 (52.0%) in EPO facilities. During 10,457 and 10,363 person-years, 248 and 372 events were recorded, respectively, for strokes and MIs. We found no differences in adjusted stroke or MI rates or their composite with cardiovascular death (HR, 1.10; 95% CI, 0.96-1.25).

LIMITATIONS

Nonrandom treatment assignment, potential residual confounding.

CONCLUSIONS

In incident hemodialysis patients, mortality and cardiovascular event rates did not differ between patients treated at facilities predominantly using DPO versus EPO.

Mortality risk of darbepoetin alfa versus epoetin alfa in patients with CKD: systematic review and meta-analysis

BACKGROUND

Epoetin alfa (EPO) and darbepoetin alfa (DPO) are erythropoiesis-stimulating agents that are widely and interchangeably used for the treatment of anemia in patients with advanced chronic kidney disease and end-stage renal disease. No study has specifically compared the risks of hard study outcomes between EPO and DPO, including mortality.

STUDY DESIGN

Systematic review of the literature and meta-analysis.

SETTING & POPULATION

Patients enrolled in randomized trials comparing EPO versus DPO for the treatment of anemia in adults with chronic kidney disease, including those requiring dialysis.

SELECTION CRITERIA FOR STUDIES

We conducted a systematic search of the literature (PubMed, CENTRAL, SCOPUS, and EMBASE, all years) and industry resources, using predefined search terms and data abstraction tools. We then summarized key characteristics and findings of these trials and performed a random-effects meta-analysis of trials with at least 3 months' duration to identify the summary OR of mortality between patients randomly assigned to DPO versus EPO.

INTERVENTION

DPO versus EPO.

OUTCOME

All-cause mortality.

RESULTS

We identified 9 trials that met the stated inclusion criteria. Overall, 2,024 patients were included in the meta-analysis, of whom 126 died during follow-up, which ranged from 20 to 52 weeks. We found no significant difference in mortality between patients randomly assigned to DPO versus EPO (OR, 1.33; 95% CI, 0.88-2.01). No treatment heterogeneity across studies was detected (Q statistic=4.60; P=0.8).

LIMITATIONS

Generalizability to nontrial populations is uncertain.

CONCLUSIONS

Few trials directly comparing DPO and EPO have been conducted and follow-up was limited. In aggregate, no effect of specific erythropoiesis-stimulating agent on mortality was identified, but the confidence limits were wide and remained compatible with considerable harm from DPO. Absent adequately powered randomized trials, observational postmarketing comparative effectiveness studies comparing these erythropoiesis-stimulating agents are required to better characterize the long-term safety profiles of these agents.

Role of recombinant human erythropoietin against mitomycin C-induced cardiac, hepatic and renal dysfunction in Wistar rats

Mitomycin C (MMC) is one of the most effective chemotherapeutic drugs. However, the dose of MMC is greatly limited by its toxicity in normal tissues. Recombinant human erythropoietin (rhEPO), an erythropoietic hormone, has also been shown to exert tissue protective effects. The purpose of this study was to explore the protective effect of rhEPO against MMC-induced heart, liver, and renal dysfunction. Adult male Wistar rats were divided into six groups (with six animals each), namely control, rhEPO alone group, MMC alone group, and rhEPO + MMC group (pre-, co-, and posttreatment conditions). The results showed that MMC induced a marked cardiac, renal, and liver failure characterized by a significant decrease in body weight, organs weight, and organs ratio and a significant increase in creatinine, blood urea nitrogen, alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transferase, and conjugated and total bilirubin levels in serum. Histological examination showed that MMC caused liver alterations. rhEPO treatment restored body weight, organs weight, and organs ratio as well as serum biochemical parameters and histological damage caused by MMC exposure.

Induction of DNA fragmentation, chromosome aberrations and micronuclei by cisplatin in rat bone-marrow cells: protective effect of recombinant human erythropoietin

Cisplatin (Cisp) is one of the most effective chemotherapeutic agents. However, at higher doses several side effects may occur. Recombinant human erythropoietin (rhEPO), a glycoprotein regulating haematopoiesis, has recently been shown to exert an important cyto-protective effects in many tissues. The purpose of this study was to explore whether rhEPO protects against Cisp-induced genotoxicity in rat bone-marrow cells. Adult male Wistar rats were divided into six groups of 18 animals each: control group, rhEPO-alone group, Cisp-alone group and three rhEPO+Cisp-groups (pre-, co- and post-treatment condition, respectively). Our results show that Cisp induced a noticeable genotoxic effect in rat bone-marrow cells. In all types of treatment, rhEPO significantly decreased the frequency of micronuclei, the percentage of chromosome aberrations and the level of DNA damage. The protective effect of rhEPO was more efficient when it was administrated 24h before exposure to Cisp.

The use of chemokine-releasing tissue engineering scaffolds in a model of inflammatory response-mediated melanoma cancer metastasis

Inflammatory responses and associated products have been implicated in cancer metastasis. However, the relationship between these two processes is uncertain due to the lack of a suitable model. Taking advantage of localized and controllable inflammatory responses induced by biomaterial implantation and the capability of tissue scaffolds to release a wide variety of chemokines, we report a novel system for studying the molecular mechanisms of inflammation-mediated cancer metastasis. The animal model is comprised of an initial subcutaneous implantation of biomaterial microspheres which prompt localized inflammatory responses, followed by the transplantation of metastatic cancer cells into the peritoneal cavity or blood circulation. Histological results demonstrated that substantial numbers of B16F10 cells were recruited to the site nearby biomaterial implants. There was a strong correlation between the degree of biomaterial-mediated inflammatory responses and number of recruited cancer cells. Inflammation-mediated cancer cell migration was inhibited by small molecule inhibitors of CXCR4 but not by neutralizing antibody against CCL21. Using chemokine-releasing scaffolds, further studies were carried out to explore the possibility of enhancing cancer cell recruitment. Interestingly, erythropoietin (EPO) releasing scaffolds, but not stromal cell-derived factor-1α-releasing scaffolds, were found to accumulate substantially more melanoma cells than controls. Rather unexpectedly, perhaps by indirectly reducing circulating cancer cells, mice implanted with EPO-releasing scaffolds had ~30% longer life span than other groups. These results suggest that chemokine-releasing scaffolds may potentially function as implantable cancer traps and serve as powerful tools for studying cancer distraction and even selective annihilation of circulating metastatic cancer cells.

Molecular cloning and transgenic expression of a synthetic human erythropoietin gene in tobacco

Erythropoietin (EPO) is a hormone belonging to a group of hematopoietic growth factors that control the proliferation and differentiation of bone marrow cells. It induces the production of erythrocytes, thereby increasing the amount of circulating hemoglobin and oxygen. Previous attempts to transgenically express human EPO in plants failed to succeed because the plants exhibited abnormal morphology and infertility. In the present work, we describe the generation of fertile transgenic tobacco plants able to express a synthetic version of human EPO. A 582-bp fragment of the human EPO gene was synthesized using a PCR-based method and ligated into pCR-Blunt. After sequencing, the human EPO fragment was transferred to pWUbi.tm1 and the expression cassette was then transferred to the binary vector pWBVec4a. After Agrobacterium-mediated transformation of Nicotiana tabacum SR1 plants, integration of the transgene into T(0) and T(1) plant genomes was confirmed by PCR. The human EPO gene was found to be expressed in tobacco leaves at the mRNA and protein levels. Self-crossing allowed us to obtain T(1) plants exhibiting Mendelian segregation of the transgene. None of the plants presented any kind of malformation or deformity.

Erythropoietin gene-enhanced marrow mesenchymal stromal cells decrease cisplatin-induced kidney injury and improve survival of allogeneic mice

Bone marrow-derived mesenchymal stromal cells (MSCs) are promising for regenerative medicine applications, such as for renoprotection and repair in acute kidney injury (AKI). Erythropoietin (Epo) can also exert cytoprotective effects on various tissues including the kidney. We hypothesized that MSCs gene-enhanced to secrete Epo may produce a significant beneficial effect in AKI. Mouse Epo-secreting MSCs were generated, tested in vitro, and then implanted by intraperitoneal injection in allogeneic mice previously administered cisplatin to induce AKI. Epo-MSCs significantly improved survival of implanted mice as compared to controls (67% survival versus 33% with Vehicle only). Also, Epo-MSCs led to significantly better kidney function as shown by lower levels of blood urea nitrogen (72 ± 9.5 mg/dl versus 131 ± 9.20 mg/dl) and creatinine (74 ± 17 µmol/l versus 148±19.4 µmol/l). Recipient mice also showed significantly decreased amylase and alanine aminotransferase blood concentrations. Kidney sections revealed significantly less apoptotic cells and more proliferating cells. Furthermore, PCR revealed the presence of implanted cells in recipient kidneys, with Epo-MSCs leading to significantly increased expression of Epo and of phosphorylated-Akt (Ser473) (P-Akt) in these kidneys. In conclusion, our study demonstrates that Epo gene-enhanced MSCs exert significant tissue protective effects in allogeneic mice with AKI, and supports the potential use of gene-enhanced cells as universal donors in acute injury.

A pilot study to evaluate the safety and clinical outcomes of once-weekly epoetin alfa 80,000 u in anemic patients with cancer receiving chemotherapy

BACKGROUND

Epoetin alfa is indicated for the treatment of chemotherapy-induced anemia at doses of 150 U/kg 3 times weekly or 40,000 U once weekly. Higher starting doses may lead to higher hematologic response rates (RRs), earlier hematologic responses, and earlier identification of nonresponders. The hematologic response and safety of epoetin alfa at a starting dose of 80,000 U once weekly in anemic patients (hemoglobin [Hb] </= 11 g/dL) with nonmyeloid malignancies receiving chemotherapy were evaluated in this open-label, multicenter pilot study.

PATIENTS AND METHODS

Epoetin alfa was initiated at 80,000 U once weekly and reduced if Hb increased to > 13 g/dL or increased > 1.3 g/dL in a 2-week period during the 12-week study. The primary efficacy endpoint was major hematologic response (Hb increase >/= 2 g/dL or Hb >/=12 g/dL, independent of transfusion). Secondary endpoints were minor hematologic response (Hb increase >/= 1 g/dL but > 2 g/dL) and incidence of transfusions.

RESULTS

Of 69 patients enrolled, 47 (68%) completed the study. A majority of patients (72%) exhibited a major hematologic response with epoetin alfa 80,000 U once weekly. Mean Hb levels increased by 2.2 g/dL from baseline after 12 weeks of therapy. Six patients (8.8%) received packed red blood cell transfusions during the study. The dose of epoetin alfa was reduced, or held then reduced, per protocol in 48 patients (69.6%). Ten patients (14.5%) in the safety population experienced a total of 11 clinically relevant thrombotic vascular events.

CONCLUSION

Epoetin alfa at a starting dose of 80,000 U once weekly (with appropriate dose reductions) increased Hb level, was associated with a packed red blood cell transfusion rate > 5% after 4 weeks of therapy, and was safe and generally well tolerated in anemic patients with cancer receiving chemotherapy. The hematologic RR, however, was not markedly improved compared with previous trials with 40,000-60,000 U once weekly, perhaps partly because of the high frequency of dose reductions.

Management of Cancer-related Cognitive Dysfunction-Conceptualization Challenges and Implications for Clinical Research and Practice

Cancer-related cognitive dysfunction (CRCD)-especially impairments in attention and memory-constitutes a significant problem for cancer patients and survivors. Incidence rates of CRCD range from 17 to 75%. Cognitive impairment experienced by cancer patients can be severe and long-lasting. Strategies to ameliorate this condition have been hindered by difficulties in understanding the precise etiology of CRCD and a lack of consensus on appropriate and reliable assessment approaches. This article provides an overview of the magnitude of the problem and discusses pathophysiology, current theories, clinical presentation, assessment concerns, and management of CRCD.

An extended maintenance dosing regimen of epoetin alfa 80,000 U every 3 weeks in anemic patients with cancer receiving chemotherapy

BACKGROUND

The purpose of this study was to evaluate the safety and efficacy of epoetin alfa (EPO) at an initial dose of 60,000 Units (U) once weekly (QW) followed by extended dosing of 80,000 U every 3 weeks (Q3W) in patients with chemotherapy-induced anemia (CIA).

MATERIALS AND METHODS

Anemic patients (hemoglobin [Hb] < or = 11 g/dl) receiving Q3W chemotherapy for nonmyeloid malignancy were enrolled in this prospective, open-label, single-arm study to receive EPO 60,000 U subcutaneously (SC) QW (initial dosing phase [IDP]) until a target Hb level of 12 g/dl was reached (maximum 12 weeks). Patients who achieved an Hb level of 12 g/dl at any point during the IDP then entered the extended dosing phase (EDP; EPO 80,000 U SC Q3W). Maximum study duration (IDP + EDP) was 24 weeks. The primary endpoint was the proportion of patients achieving a hematopoietic response (Hb increase > or = 2 g/dl from baseline or Hb > or = 12 g/dl) during the IDP.

RESULTS

One hundred fifteen patients were enrolled. During the IDP, 76% (84/110) of patients achieved a hematopoietic response, and 15% (17/115) received red blood cell (RBC) transfusion. Sixty-three percent (73/115) of patients entered the EDP, and 88% (64/73) of these patients maintained a mean Hb level > 11.0 and < or =13.0 g/dl. Two of 73 patients received RBC transfusion during the EDP. Adverse events were consistent with the underlying disease and chemotherapy treatment.

CONCLUSION

These results suggest that initiation of EPO 60,000 U SC QW is effective in the treatment of CIA and that EPO 80,000 U SC Q3W can be an effective extended dosing option.

Expression of erythropoietin receptor and in vitro functional effects of epoetins in B-cell malignancies

PURPOSE

Erythropoietin (EPO) and EPO receptor (EPO-R) expression have been reported in solid tumors and are claimed to regulate tumor growth; however, no data have been published on this issue in B-cell malignancies or normal lymphoid cells. This report describes genomic/protein EPO-R expression and in vitro effects of recombinant human EPO (epoetin) in B-cell chronic lymphocytic leukemia (B-CLL), mantle-cell lymphoma (MCL), and multiple myeloma (MM).

EXPERIMENTAL DESIGN

Blood samples were obtained from patients with B-CLL, MCL, and healthy volunteers, and bone marrow was obtained from MM patients. EPO-R mRNA was detected by reverse transcription-PCR. EPO-R surface expression was investigated by flow cytometry using digoxigenin-labeled epoetin and polyclonal rabbit anti-EPO-R antibody for intracellular receptor. Tumor cell stimulation was determined in vitro using [(3)H]thymidine incorporation and CD69 expression after exposure to epoetin alpha or beta or darbepoetin alpha.

RESULTS

EPO-R mRNA was detected in mononuclear cells from 32 of 41 (78%) B-CLL and 5 of 7 (71%) MCL patients, and 21 of 21 (100%) MM samples. Expression was also detected in highly purified T cells from six of eight B-CLL patients, four of four MM patients, and normal donor B and T cells. Surface EPO-R protein was not detected. Intracellular EPO-R staining with anti-EPO-R antibodies was unspecific. No tumor-stimulatory effect was observed with high epoetin concentrations.

CONCLUSIONS

EPO-R gene is frequently expressed in lymphoid malignancies and normal B and T cells. However, there was no surface protein expression and no epoetin-induced in vitro stimulation of tumor B cells, indicating that epoetin therapy in vivo is likely to be safe in patients with lymphoid malignancies.

The role of erythropoietin in central and peripheral nerve injury

Erythropoietin (Epo) is a cytokine which controls red cell production. Apart from the red cell surface, erythropoietin's receptor (Epo-R) is also expressed in a large variety of normal tissues. Erythropoietin, as well as its receptor, is present in the central and peripheral nervous system. As erythropoietin having direct and indirect effect on nerve cells, enhances antioxidotic enzyme production, antagonizes glutamate's cytotoxic action, metabolizes free radicals, normalizes cerebral blood flow, affects neurotransmitters release and stimulates neoangiogenesis. After injury of the central as well as the peripheral nervous system, Epo presents an anti-apoptotic action. In combination with its anti-apoptotic effect, Epo, by reducing the inflammatory response plays a crucial role in neuroprotection in many types of injury in the central and the peripheral nervous system. Epo's administration contributes to the recovery of mechanical allodynia and may be effective in peripheral nerve regeneration after neurorrhaphy.

Survival and erythropoietin receptor protein in tumours from patients randomly treated with rhEPO for palliative care

BACKGROUND

Recombinant erythropoietin (rhEPOalpha) corrects anaemia, improves physical functioning and quality of life in cancer patients. However, published reports have suggested risks for tumour stimulation by provision EPO to patients with remaining tumour cells perhaps related to the presence of EPO receptor protein in tumour tissue. Therefore, the aim of the present study was to exclude a possibility that cancer patients who respond favourably to EPO treatment have mainly tumours with low EPO receptor protein expression.

METHODS

Tumour tissue was evaluated in 87 patients out of 108 randomly allocated for treatment with rhEPOalpha (n = 50) versus controls (n = 58). Tumour cell proliferation (Ki-67 index) and EPO receptor protein expression were evaluated by immunohistochemistry.

RESULTS

EPO treatment varied between 2 and 35 months, in doses between 10,000 and 40,000 Units/week. Ki-67 index did not differ between study and control patients before EPO treatment. Tumour tissue erythropoietin receptor protein was also similar between treated and untreated patients. Around 40% of tumour cells contained EPO receptors. Survival did not differ among EPO treated and control patients analysed as intention to treat, while survival was significantly improved in EPO treated patients per protocol treatment (P < 0.05). Ki-67 index and tumour tissue erythropoietin receptor protein did not predict survival, which systemic inflammation (ESR) did (P < 0.02).

CONCLUSIONS

Our results support that reported risk to accelerate disease progression by EPO treatment in palliative care is not justified in patients with solid, gastrointestinal cancer despite tumour presence of EPO receptor protein.

Anaemia of cancer: an overview of mechanisms involved in its pathogenesis

Anaemia is a common complication in cancer patients. The decrease in haemoglobin is associated with an impaired quality of life, poorer response to therapy and worse prognosis. Numerous factors are involved in the physiopathology of cancer-related anaemia. Some factors such as bleeding, bone marrow infiltration, the effects of chemoradiotherapy and associated nutritional deficiencies are related to the disease itself. In addition, the interaction of the immune system with iron metabolism and erythropoiesis has been shown to be an important factor in the development of anaemia in cancer patients and can be seen in the action of several cytokines on different iron-homeostasis and erythrocyte-cell-production pathways. Some inhibitory cytokines, such as tumour necrosis factor-alpha and interleukin-1, act on the suppression of erythroid precursor cells and erythropoietic production and response; others, such as interleukins 1 and 6 and hepcidin, impair iron metabolism, causing iron to be diverted from erythropoiesis and retained within the reticuloendothelial system. The main mechanisms involved in the development of cancer-related anaemia are discussed in this review.

Cisplatin-induced peripheral neuropathy: Neuroprotection by erythropoietin without affecting tumour growth

This study examined the dose-dependent efficacy of erythropoietin (EPO) for preventing and/or treating cisplatin (CDDP) induced peripheral neurotoxicity (CINP), and its influence on tumour treatment and growth. Rats received eight intraperitoneal (ip) injections of 2 mg/kg CDDP twice weekly. EPO co-administered (50 or 10 microg/kg ip, three times/week) had a dose-dependent effect, partially preventing CINP, but 0.5 microg/kg ip was not effective. The neuroprotective effect lasted at least 5 weeks after the last dose of EPO and CDDP. In addition, EPO (50 microg/kg ip three times/week) after the last injection of CDDP still induced a significant recovery of CINP. In a separate experiment in rats bearing mammary carcinoma EPO treatment (50 microg/kg ip) given concurrently with CDDP (1.0 and 1.5 mg/kg twice a week for four weeks) was neuroprotective without influencing the effectiveness of the treatment or tumour growth. EPO thus appears to be an effective neuroprotectant that does not interfere with tumour treatment.

Erythropoietin administration during primary treatment for locally advanced cervical carcinoma is associated with poor response to radiation

The purpose of this study was to determine whether the use of recombinant erythropoietin (r-EPO) during treatment for locally invasive carcinoma of the cervix affects recurrence rates, disease-free survival, and overall survival. Retrospective analysis of outcomes of patients with locally advanced cervical cancer treated with radiation and concurrent chemotherapy between January 1997 and July 2004 was performed. Recurrence rates, disease-free survival, and overall survival were calculated using SPSS statistical software. Throughout P < 0.05 was considered significant. Of 68 patients included in this study, 18 patients received erythropoietin during treatment and 50 did not. Patient age, stage, hemoglobin at presentation, and average weekly hemoglobin (AWH) were similar in both groups of patients. The recurrence rate among patients who received r-EPO was 61% compared with 30% among patients who did not receive r-EPO (P = 0.014). Eight of 18 patients (44%) who received r-EPO were alive at last known follow-up compared to 36 of 50 (72%) who did not receive the medication (P = 0.045). Disease-free survival and overall survival were significantly shorter in patients who received r-EPO during treatment (P = 0.028, 0.032). The administration of r-EPO during primary treatment of patients with locally advanced cervical cancer is associated with increased recurrence rate, increased risk of death due to disease, and decreased disease-free and overall survivals.

Oxygen-dependent diseases in the retina: Role of hypoxia-inducible factors

The function of the retina is sensitive to oxygen tension. Any change in the perfusion pressure of the eye affects the retina although the eye is able to autoregulate its hemodynamics. Systemic hypoxemia (lung or heart disease) or a vascular disease in the retina can cause retinal hypoxia. All the hypoxia-dependent events in cells appear to share a common denominator: hypoxia-inducible factor (HIF), which is a heterodimeric transcription factor, a protein. HIF comprises a labile alpha subunit (1-3), which is regulated, and a stable beta subunit, which is constitutively expressed. Both are helix-loop-helix factors and belong to the PAS-domain family of transcription factors. Oxygen plays the key role in stabilizing HIF-1alpha and its function. When the oxygen tension is normal, HIF-1alpha is rapidly oxidized by hydroxylase enzymes, but when cells become hypoxic, HIF-1alpha escapes the degradation and starts to accumulate, triggering the activation of a large number of genes, like vascular endothelial growth factor (VEGF) and erythropoietin. HIF-1alpha has been shown to have, either clinically or experimentally, a mediating or contributing role in several oxygen-dependent retinal diseases such as von Hippel-Lindau, proliferative diabetic retinopathy, retinopathy of prematurity and glaucoma. In retinitis pigmentosa and high-altitude retinopathy, however, the evidence is still indirect. There are three different strategies available for treating retinal diseases, which have all shown promising results: retinal cell transplantation or replacement, gene replacement, and pharmacological intervention. Specifically, recent results show that the HIF pathway can be used as a therapeutic target, although there is still a long way to go from bench to clinic. HIF can be stabilized by inhibiting prolyl hydroxylase or by blocking the VHL:HIF-alpha complex if angiogenesis is the goal, as in retinitis pigmentosa. On the other hand, the downregulation of HIF has a pivotal role if we are to inhibit neovascularization, as in proliferative diabetic retinopathy. To date, several small-molecule inhibitors of HIF have been developed and are entering clinical trials. HIF is a remarkable example of a single transcription factor that can be regarded as a "master switch" regulating all the oxygen-dependent retinal diseases.

Utilisation de l'érythropoïétine recombinante humaine chez l'enfant atteint de cancer

Eighty percent of children with cancer suffer from anemia at the time of diagnosis. The physiopathology of anemia is complex. Although anemia can be life threatening, its consequences on the physical, psychological and social state of the child are often minimized. Blood transfusion is the main treatment of anemia: its efficacy is immediate but shortlasting, and it involves infectious and hemolytic risks. The human recombinant erythropoietin has been used for more than 25-years, and is often prescribed to adults with cancer and anemia. The human recombinant erythropoietin rHuEPO is nowadays used when blood transfusion is contra-indicated because of religious or cultural considerations, although several promising studies have been conducted about rHuEPO and children with cancer since 1996: it might be soon the preferential alternative treatment to anemia in children with cancer.

Anemia, tumor hypoxemia, and the cancer patient

PURPOSE

To review the impact of anemia/tumor hypoxemia on the quality of life and survival in cancer patients, and to assess the problems associated with the correction of this difficulty.

METHODS

MEDLINE searches were performed to find relevant literature regarding anemia and/or tumor hypoxia in cancer patients. Articles were evaluated in order to assess the epidemiology, adverse patient effects, anemia correction guidelines, and mechanisms of hypoxia-induced cancer cell growth and/or therapeutic resistance. Past and current clinical studies of radiosensitization via tumor oxygenation/hypoxic cell sensitization were reviewed. All clinical studies using multi-variate analysis were analyzed to show whether or not anemia and/or tumor hypoxemia affected tumor control and patient survival. Articles dealing with the correction of anemia via transfusion and/or erythropoietin were reviewed in order to show the impact of the rectification on the quality of life and survival of cancer patients.

RESULTS

Approximately 40-64% of patients presenting for cancer therapy are anemic. The rate of anemia rises with the use of chemotherapy, radiotherapy, and hormonal therapy for prostate cancer. Anemia is associated with reductions both in quality of life and survival. Tumor hypoxemia has been hypothesized to lead to tumor growth and resistance to therapy because it leads to angiogenesis, genetic mutations, resistance to apoptosis, and a resistance to free radicals from chemotherapy and radiotherapy. Nineteen clinical studies of anemia and eight clinical studies of tumor hypoxemia were found that used multi-variate analysis to determine the effect of these conditions on the local control and/or survival of cancer patients. Despite differing definitions of anemia and hypoxemia, all studies have shown a correlation between low hemoglobin levels and/or higher amounts of tumor hypoxia with poorer prognosis. Radiosensitization through improvements in tumor oxygenation/hypoxic cell sensitization has met with limited success via the use of hyperbaric oxygen, electron-affinic radiosensitizers, and mitomycin. Improvements in tumor oxygenation via the use of carbogen and nicotinamide, RSR13, and tirapazamine have shown promising clinical results and are all currently being tested in Phase III trials. The National Comprehensive Cancer Network (NCCN) guidelines recommend transfusion or erythropoietin for symptomatic patients with a hemoglobin of 10-11 g/dl and state that erythropoietin should strongly be considered if hemoglobin falls to less than 10 g/dl. These recommendations were based on studies that revealed an improvement in the quality of life of cancer patients, but not patient survival with anemia correction. Phase III studies evaluating the correction of anemia via erythropoietin have shown mixed results with some studies reporting a decrease in patient survival despite an improvement in hemoglobin levels. Diverse functions of erythropoietin are reviewed, including its potential to inhibit apoptosis via the JAK2/STAT5/BCL-X pathway. Correction of anemia by the use of blood transfusions has also shown a decrement in patient survival, possibly through inflammatory and/or immunosuppressive pathways.

CONCLUSIONS

Anemia is a prevalent condition associated with cancer and its therapies. Proper Phase III trials are necessary to find the best way to correct anemia for specific patients. Future studies of erythropoietin must evaluate the possible anti-apoptotic effects by directly assessing the tumor for erythropoietin receptors or the presence of the JAK2/STAT5/BCL-X pathway. Due to the ability of transfusions to cause immunosuppression, most probably through inflammatory pathways, it may be best to study the effects of transfusion with the prolonged use of anti-inflammatory medications.

Role of c-Kit and erythropoietin receptor in erythropoiesis

Erythropoiesis is regulated by a number of growth factors, among which stem cell factor (SCF) and erythropoietin (Epo) play a non-redundant function. Viable mice with mutations in the SCF gene (encoded by the Steel (Sl) locus), or its receptor gene c-Kit (encoded by the White spotting (W) locus) develop a hypoplastic macrocytic anemia. Mutants of W or Sl that are completely devoid of c-Kit or SCF expression die in utero of anemia between days 14 and 16 of gestation and contain reduced numbers of erythroid progenitors in the fetal liver. Likewise, Epo and Epo receptor (Epo-R)-deficient mice die in utero due to a marked reduction in the number of committed fetal liver derived erythroid progenitors. Thus, committed erythroid progenitors require both c-Kit and Epo-R signal transduction pathways for their survival, proliferation and differentiation. In vitro, Epo alone is capable of generating mature erythroid progenitors; however, a combined treatment of Epo and SCF results in synergistic proliferation and expansion of developing erythroid progenitors. This review summarizes recent advances made towards understanding the signaling mechanisms by which Epo-R and c-Kit regulate growth, survival, and differentiation of erythroid progenitors alone and cooperatively.

Preclinical and clinical studies: A preview of potential future applications of erythropoietic agents

Understanding the tissue distribution of erythropoietin receptors and cellular actions of erythropoietic agents may facilitate the development of wider applications for these compounds. Erythropoietin receptors have been identified in the central nervous system (CNS), retina, heart, vascular endothelium, kidney, lung, liver, gastrointestinal and reproductive tracts, and erythroid bone marrow precursors. Potential benefits of erythropoietic agents in several therapeutic areas may result from actions other than hematopoiesis stimulation. Their hematopoietic effects may also have broader applications in treating anemia of the elderly and non-chemotherapy (CT)-related anemia in patients with cancer. Furthermore, because hypoxic tumor cells tend to be more resistant to radiation therapy (RT) and some forms of CT, and more aggressive than normoxic cells, increased oxygenation resulting from anemia correction may increase RT and CT sensitivity, possibly impacting treatment outcomes. However, clinical studies addressing this hypothesis have conflicting results. Preliminary evidence suggests erythropoietin has CNS neuroprotective effects, including potential clinical benefits in ischemic stroke. In addition, data suggest that erythropoietin (epoetin alfa) may attenuate declines in cognitive function during CT for early-stage breast cancer. Erythropoietin may have benefits in retinal disease, peripheral neuropathy, and myocardial ischemia. Thus, accumulating evidence suggests that erythropoietic agents may have clinical utility outside CT-related anemia.

Erythropoietin (epoetin) as a protective factor for the brain

Erythropoietin (EPO) has been viewed traditionally as a hematopoietic cytokine. Emerging evidence now exists supporting a physiologic role for EPO within the nervous system. EPO is expressed in the developing central nervous system and is capable of regulating the production of neuronal progenitor cells. There are numerous preclinical studies demonstrating a neuroprotective potential for EPO in a variety of disorders of both the central and peripheral nervous systems. A small pilot study in patients with acute ischemic stroke has recently been completed and the results are encouraging. Its mechanism of action is multifactorial but probably related to its ability to act as an antiapoptotic agent. Its widespread use clinically for the treatment of anemias has given us the experience and knowledge of its safety and pharmacokinetics. EPO is thus an ideal compound to study for the potential treatment of a variety of neurologic disorders.