Erythropoietic stimulating agents

Pediatric Patient Blood Management Programs: Not Just Transfusing Little Adults

Red blood cell transfusions are a common life-saving intervention for neonates and children with anemia, but transfusion decisions, indications, and doses in neonates and children are different from those of adults. Patient blood management (PBM) programs are designed to assist clinicians with appropriately transfusing patients. Although PBM programs are well recognized and appreciated in the adult setting, they are quite far from standard of care in the pediatric patient population. Adult PBM standards cannot be uniformly applied to children, and there currently is significant variation in transfusion practices. Because transfusing unnecessarily can expose children to increased risk without benefit, it is important to design PBM programs to standardize transfusion decisions. This article assesses the key elements necessary for a successful pediatric PBM program, systematically explores various possible pediatric specific blood conservation strategies and the current available literature supporting them, and outlines the gaps in the evidence suggesting need for further/improved research. Pediatric PBM programs are critically important initiatives that not only involve a cooperative effort between pediatric surgery, anesthesia, perfusion, critical care, and transfusion medicine services but also need operational support from administration, clinical leadership, finance, and the hospital information technology personnel. These programs also expand the scope for high-quality collaborative research. A key component of pediatric PBM programs is monitoring pediatric blood utilization and assessing adherence to transfusion guidelines. Data suggest that restrictive transfusion strategies should be used for neonates and children similar to adults, but further research is needed to assess the best oxygenation requirements, hemoglobin threshold, and transfusion strategy for patients with active bleeding, hemodynamic instability, unstable cardiac disease, and cyanotic cardiac disease. Perioperative blood management strategies include minimizing blood draws, restricting transfusions, intraoperative cell salvage, acute normovolemic hemodilution, antifibrinolytic agents, and using point-of-care tests to guide transfusion decisions. However, further research is needed for the use of intravenous iron, erythropoiesis-stimulating agents, and possible use of whole blood and pathogen inactivation. There are numerous areas where newly formed collaborations could be used to investigate pediatric transfusion, and these studies would provide critical data to support vital pediatric PBM programs to optimize neonatal and pediatric care.

Perioperative assessment of the cancer patient

The perioperative evaluation of patients with cancer differs from that of other patients in that the former may have received prior chemotherapy or radiation therapy. These cancer treatments have a wide range of side effects and complications that may affect patients' perioperative risks. The perioperative specialist who evaluates the cancer patient prior to surgery must be familiar with the effects of these treatments and their consequences for the major organ systems. The perioperative specialist must also be familiar with the natural history of cancer and have a basic understanding of how cancer affects the body. In this article, we review the perioperative concerns that are specific to the patient with cancer.

Blood management

Blood management is a system-based comprehensive approach that uses evidence-based medicine to facilitate an environment to encourage an appropriate use of blood products in the hospital setting. The ultimate goal of a blood-management program is to improve patient outcomes by integrating all available techniques to ensure safety, availability, and appropriate allocation of blood products. It is a patient-centered, multidisciplinary, multimodal, planned approach to the management of patients and blood products.

Hematological interventions in NICU care: the use of rEpo, IVIG, and rG-CSF

This article focuses on the use of rEpo, IVIG, and rG-CSF in the NICU. It discusses the most recent studies and the most definitive and clinically relevant evidence, rather than summarizing all published studies. The last section was written for NICU practice groups that choose to use any of these medications and are seeking a consistent approach for doing so. The section provides the author's approach to the use of rEpo, IVIG, and rG-CSF, revealing personal preferences, interpretations, and experiences, and is based on the dictum, "if you are going to use it, use it the same way each time."

Design, modeling, expression, and chemoselective PEGylation of a new nanosize cysteine analog of erythropoietin

Background:

Recombinant human erythropoietin (rhEPO) is considered to be one of the most pivotal pharmaceutical drugs in the market because of its clinical application in the treatment of anemia-associated disorders worldwide. However, like other therapeutic proteins, it does not have suitable pharmacokinetic properties for it to be administrated at least two to three times per week. Chemoselective cysteine PEGylation, employing molecular dynamics and graphics in in silico studies, can be considered to overcome such a problem.

Methods:

A special kind of EPO analog was elicited based on a literature review, homology modeling, molecular dynamic simulation, and factors affecting the PEGylation reaction. Then, cDNA of the selected analog was generated by site-directed mutagenesis and subsequently cloned into the expression vector. The construct was transfected to Chinese hamster ovary/dhfr⁻ cells, and highly expressed clones were selected via methotrexate amplification. Ion-immobilized affinity and size exclusion (SE) chromatography techniques were used to purify the expressed analog. Thereafter, chemoselective PEGylation was performed and a nanosize PEGylated EPO was obtained through dialysis. The in vitro biologic assay and in vivo pharmacokinetic parameters were studied. Finally, E31C analog Fourier transform infrared, analytical SE-high-performance liquid chromatography, zeta potential, and size before and after PEGylation were characterized.

Results:

The findings indicate that a novel nanosize EPO31-PEG has a five-fold longer terminal half-life in rats with similar biologic activity compared with unmodified rhEPO in proliferation cell assay. The results also show that EPO31-PEG size and charge versus unmodified protein was increased in a nanospectrum, and this may be one criterion of EPO biologic potency enhancement.

Discussion:

This kind of novel engineered nanosize PEGylated EPO has remarkable advantages over rhEPO.

Non-erythropoietic erythropoietin derivatives protect from light-induced and genetic photoreceptor degeneration

Given the high genetic heterogeneity of inherited retinal degenerations (IRDs), a wide applicable treatment would be desirable to halt/slow progressive photoreceptor (PR) cell loss in a mutation-independent manner. In addition to its erythropoietic activity, erythropoietin (EPO) presents neurotrophic characteristics. We have previously shown that adeno-associated viral (AAV) vector-mediated systemic EPO delivery protects from PR degeneration. However, this is associated with an undesired hematocrit increase that could contribute to PR protection. Non-erythropoietic EPO derivatives (EPO-D) are available which allow us to dissect erythropoiesis's role in PR preservation and may be more versatile and safe than EPO as anti-apoptotic agents. We delivered in animal models of light-induced or genetic retinal degeneration either intramuscularly or subretinally AAV vectors encoding EPO or one of the three selected EPO-D: the mutant S100E, the helix A- and B-derived EPO-mimetic peptides. We observed that (i) systemic expression of S100E induces a significantly lower hematocrit increase than EPO and provides similar protection from PR degeneration, and (ii) intraocular expression of EPO-D protects PR from degeneration in the absence of significant hematocrit increase. On the basis of this, we conclude that erythropoiesis is not required for EPO-mediated PR protection. However, the lower efficacy observed when EPO or S100E is expressed intraocularly rather than systemically suggests that hormone systemic effects contribute to PR protection. Unlike S100E, EPO-mimetic peptides preserve PR only when given locally, suggesting that different EPO-D have a different potency or mode of action. In conclusion, our data show that subretinal delivery of AAV vectors encoding EPO-D protects from light-induced and genetic PR degeneration.

Assessment and treatment of preoperative anemia: Continuing Professional Development

PURPOSE

The purpose of this continuing professional development (CPD) module is to review the risk of anemia and transfusion in perioperative patients and to propose an approach for the diagnosis and treatment of preoperative anemia.

PRINCIPAL FINDINGS

Preoperative anemia has been associated with increased transfusion of red blood cells, organ injury, and mortality. Postoperative anemia has also been associated with impaired recovery from surgery. Transfusion also increases the risk of infection, organ injury, and mortality. Preoperatively, iron deficiency anemia can be corrected with oral or intravenous iron; certain types of patients might respond to administration of erythrocyte stimulating agents (ESAs). With ESAs, the increased risk of thrombosis should be balanced against the expected benefit.

CONCLUSIONS

Preoperative diagnosis and treatment of anemia may reduce the risk of morbidity and mortality associated with both anemia and transfusion.

Very low birth weight infants qualifying for a 'late' erythrocyte transfusion: does giving darbepoetin along with the transfusion counteract the transfusion's erythropoietic suppression?

OBJECTIVE

Red blood cell (RBC) transfusions can suppress erythropoiesis. On this basis, RBC transfusions administered to very low birth weight (VLBW) neonates potentially render them more likely to qualify for a subsequent transfusion.

STUDY DESIGN

We hypothesized that 'late' (>14 days after birth) RBC transfusions given to VLBW neonates result in a decrease in reticulocyte count persisting for at least 7 to 10 days. We also hypothesized that a single dose of darbepoetin given along with the transfusion would have the opposite effect, increasing the reticulocyte count for at least 7 to 10 days. To test this, we conducted a single-centered randomized trial with 20 VLBW neonates who, according to our transfusion guidelines, qualified for a late transfusion.

RESULT

VLBW infants about to receive a late RBC transfusion were randomized (1:1) to also receive vs not receive (controls) a single subcutaneous dose of darbepoetin (10 μg kg(-1)). Reticulocyte counts diminished significantly in the controls (a drop of 85±62 × 10(3) μl(-1) (mean±s.d.) at 7 to 10 days), but increased significantly in the darbepoetin recipients (an increase of 177±120 × 10(3) μl(-1) at 7 to 10 days, P<0.0001). At 7 to 10 days after the transfusion, hematocrits of the controls were 8.1±4.9 points above their pre-transfusion values and of the darbepoetin group were 12.4±2.7 points above their pre-transfusion values (P=0.033).

CONCLUSION

This was a limited-scope, single-centered, randomized trial intended to pilot-test a new concept in neonatal transfusion practice. Namely, we tested whether a late RBC transfusion suppressed reticulocytosis and whether a concomitant single dose of darbepoetin counteracted that suppression. Using the pilot data presented in this study, larger trials can now be designed to address meaningful clinical outcomes such as transfusion avoidance using this approach.