Is there a role for autologous/placental red blood cell transfusions in the anemia of prematurity?

Why might cord blood be a better source of platelets for transfusion to neonates?

Thrombocytopenia (defined as a platelet count <150×109/L) is a common condition in preterm neonates and may occur in 18-35% of all infants admitted to the Neonatal Intensive Care Unit (NICU). Neonatal platelet functionality in terms of reactivity is often described as reduced compared to adults, even in healthy, term neonates. However, this platelet "hyporeactivity" does not correspond to a global functional impairment of the normal delicately balanced neonatal hemostatic system. The extent to which neonatal thrombocytopenia and platelet hyporeactivity contribute to the bleeding risk in preterm neonates remains unknown. Prophylactic platelet transfusions are often administered to them to reduce the risk of bleeding. However, recent literature indicates that adopting a higher platelet transfusion threshold than a lower one results in significantly higher death rates or major bleeding and can be harmful. Although the mechanism by which this occurs is not entirely clear, a mismatch between adult transfused platelets and the neonatal hemostatic system, as well as volume overload, are speculated to be potentially involved. Therefore, future research should consider novel transfusion products that may be more suitable for premature neonates. Blood products derived from umbilical cord blood (UCB) are promising, as they might perfectly match neonatal blood features. Here, we discuss the current knowledge about UCB-derived products, focusing on UCB-derived platelet concentrates and their potential for future clinical application. We will discuss how they may overcome the potential risks of transfusing adult-derived platelets to premature infants while maintaining efficacy.

Banked term umbilical cord blood to meet the packed red blood cell transfusion needs of extremely-low-gestational-age neonates: a feasibility analysis

OBJECTIVES

To assess the feasibility of drawing, processing, safety-testing, and banking term umbilical cord blood to meet the packed red blood cell transfusion (RBC Tx) needs of extremely-low-gestational-age neonates (ELGANs).

DESIGN

(1) Retrospectively analyze all ELGANs RBC Tx over the past three years, (2) Estimate local cord blood availability, (3) Assess interest in this project, and implementation barriers, through stakeholder surveys.

RESULTS

In three years we cared for 266 ELGANs; 165 (62%) received ≥1 RBC Tx. Annual RBC Tx averaged 197 (95% CI, 152-243). If 10% of our 10,353 annual term births had cord blood drawn and processed, and half of those tested were acceptable for Tx, collections would exceed the 95th % upper estimate for need by >four-fold. Interest exceeded 97%. Identified barriers included FDA approval, training to collect cord blood, and cost.

CONCLUSION

RBC Tx needs of ELGANS could be met by local cord blood collection.

New frontiers in neonatal red blood cell transfusion research

Red blood cell (RBC) transfusions are common in neonates requiring intensive care. Recent studies have compared restricted versus liberal transfusion guidelines, but limitations exist on evaluations of outcomes in populations that never required a transfusion compared to those receiving any transfusion. Although there are well-established risks associated with RBC transfusions, new data has emerged that suggests additional clinically relevant associations, including adverse neurodevelopmental outcomes, donor sex differences, and inflammation or immunosuppression. Further research is needed to delineate the magnitude of these risks and to further improve the safety of transfusions. The goal of this review is to highlight underappreciated, yet clinically important risks associated with neonatal RBC transfusions and to introduce several areas in which neonates may uniquely benefit from alterations in practice.

Haemoglobin Levels in Early Life among Infants with and without Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is a proliferative retinal vascular disorder attributed to an ischaemic stimulus in preterm infants. Haemoglobin, the main component for oxygen transportation, may be implicated in ROP development. This retrospective study compared the mean weekly haemoglobin levels between infants with and without ROP over the first six weeks of life. Premature infants of less than 32 weeks gestational age and less than 1.5 kg birth weight were grouped into age and birth weight-matched ROP cases and controls. Weekly mean haemoglobin levels were documented. An independent t-test was used to analyze the difference in mean haemoglobin levels between infants with ROP and infants without ROP. Adjustment for confounders was performed using one-way analysis of covariance. There was a statistically significant difference in adjusted mean haemoglobin levels between the ROP and non-ROP group during the first week of life (p = 0.038). No significant intergroup differences were observed at the other weeks. Haemoglobin monitoring during the first week of postnatal life may be useful to guide ROP screening in premature infants.

Deformability of cord blood vs. newborns' red blood cells: implication for blood transfusion

AIM

About 50% of premature neonates (PN) are treated with transfusion of packed red blood cells (PRBC) collected from adult donors, which has been suggested to potentially provoke PN pathologies, characterized as blood circulation disorders. RBC have properties that are key determinants of blood circulation, primarily the cell deformability. In previous studies we have shown that transfusion of RBC with reduced deformability impaired the transfusion outcome. Although RBC of PN (PN-RBC) are larger, and their microvessels are narrower than those of adults, their blood circulation is very efficient, pointing to the possibility that the deformability of adults' PRBC is inferior to that of PN-RBC, and that treating PN with PRBC transfusion might, therefore, introduce a risk to the recipients. This would infer that PN should be given RBC with high deformability. However, since using PN-RBC is not feasible, the use of cord blood RBC (CB-RBC) is a sound alternative, assuming that the deformability of CB-RBC is comparable to that of PN-RBC.The present study is aimed at testing this hypothesis.

METHODS

We compared the deformability of (1) RBC of PN vs. the PRBC they received, and (2) PN-RBC vs. their autologous CB-RBC.

RESULTS

1. The deformability of the transfused PRBC is indeed inferior to that of PN-RBC. 2. The deformability of CB-RBC is equivalent to that of PN-RBC.

CONCLUSION

This study supports the notion that treating PN with transfusion of adults' PRBC has the potential to introduce a circulatory risk to the recipients, while CB-RBC, with their superior deformability, provides a safer and more effective PN-specific transfusion therapy.

Umbilical cord blood: Current uses for transfusion and regenerative medicine

The past 20 years of experience with umbilical cord blood transplantation have demonstrated that cord blood is effective in the treatment of a spectrum of diseases, including hematological malignancies, bone marrow failure, hemoglobinopathies, and inborn errors of metabolism. However, only a few number of umbilical cord blood units collected have a cell content adequate for an allogenic hematopoietic stem cell transplantation. In the meanwhile, there is an increasing interest in exploiting cord blood derivatives in different fields. In this review, we will summarize the most recent updates on clinical applications of umbilical cord blood platelet derivatives for regenerative medicine, and we will revise the literature concerning the use of umbilical cord blood for autologous or allogeneic transfusion purposes. The methodological aspect and the biological characteristics of these products also will be discussed.

Autologous umbilical cord blood for red cell concentrate transfusion in preterm infants in the era of delayed cord clamping: An uncontrolled clinical trial

OBJECTIVE

To assess the utility of autologous umbilical cord blood (UCB) for red cell concentrate (RCC) transfusion in preterm infants.

METHODS

We recruited preterm infants born at ≤30 weeks' gestation or have an estimated fetal weight <1,200 g. We intended to perform delayed cord clamping (DCC) and to collect UCB following DCC. The quality parameters used included blood culture performed once, and biochemical and haematological parameters assessed weekly.

RESULTS

Of the 46 recruited neonates, DCC could be performed for 1 minute in 11 (23.9%) and for 30-59 seconds in 10 (21.7%) infants. The success rate of UCB collection was significantly lower in infants who underwent DCC for 1 minute (27%) compared to those who underwent DCC for 30-59 seconds (70%) or immediate cord clamping (72%) (p value 0.031). Twenty-five UCBs were stored after eliminating three that had positive culture. UCB had satisfactory quality for transfusion from day 3 (when blood culture report was available) to 14 (after which pH decreased to <6.5). Thirteen infants required 27 RCC transfusions. Autologous UCB could be used for only five (18.5%) transfusions.

CONCLUSION

The success rate of UCB collection after DCC for 1 minute is low. Autologous UCB meets less than one-fifth of transfusion requirements. Hence, autologous UCB transfusion is not a workable option in preterm infants.

Is placental blood a reliable source for the evaluation of neonatal hemostasis at birth?

BACKGROUND

Phlebotomy is among the main determinants of anemia of prematurity. Blood sparing policies endorsed umbilical cord blood (here called placental) as an alternative source for laboratory testing. Little is known on the suitability of placental blood to evaluate neonatal hemostasis of newborn infants. We aimed to compare the hemostatic profile of paired placental and infant venous blood, by means of prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, antithrombin, protein C, thromboelastography (TEG) and thrombin generation assay (TGA).

STUDY DESIGN

This was an observational single-center study.

METHODS

We collected at birth venous citrated blood from both placental and infant venous source and performed PT, APTT, fibrinogen, antithrombin, protein C, TEG (reaction time-R; kinetics-K alpha angle-α, maximum amplitude-MA and lysis at 30 minutes-LY30), and TGA (endogenous thrombin potential-ETP).

RESULTS

We enrolled 60 neonates with a median gestational age (range) of 37 weeks (28⁺¹ -41) and birth-weight 2417 g (950-4170). Based on TEG and TGA, placental blood showed a procoagulant imbalance as indicated by lower median R (4.0 vs. 6.1 min; p < 0.001) and K (1.3 vs. 2.2 min; p < 0.001); higher α-angle (69.7 vs. 57.4°; p < 0.001) and ETP (1260 vs. 1078; p = 0.002) than those observed for infant venous blood. PT and APTT did not differ significantly between the two groups.

CONCLUSIONS

While placental and neonatal blood samples are equally suitable to measure the standard coagulation tests PT and APTT, placental blood leads to a procoagulant imbalance when testing is performed with TEG or TGA. These effects should be considered when interpreting results stemming from investigation of neonatal hemostasis.

The Use of Umbilical Cord Blood for Autologous Transfusion in Neonatal Open Heart Surgery

In the last few decades, the use of umbilical cord blood (UCB) has received increasing attention, not only as a source of stem cells, but also as a transfusion product for the treatment of anemia in the neonatal and even the adult population. This review focuses on data reports and collection efforts related to the autologous transfusion of UCB in full-term neonates with prenatally diagnosed critical congenital heart defects. This review summarizes different aspects of UCB transfusion, including indications and contraindications; the collection procedure; storage timing; and special properties of one of its constituents, fetal hemoglobin, in the setting of hypothermic cardiopulmonary bypass.

Umbilical cord blood as a source for red-blood-cell transfusion in neonatology: a systematic review

The prevention and treatment of anaemia in newborn patients made tremendous progress in the last decades. However, red-blood-cell (RBC) transfusions remain unavoidable in many neonates candidate to surgery and especially in preterm infants. In particular, anaemia occurring in neonates born at extremely low gestational age is actually severe and frequently requires transfusions. Several approaches have been explored to prevent or even to reduce the threshold and the frequency of RBC transfusions. Among these, umbilical cord blood (UCB) collection and processing to obtain RBC components for autologous or allogeneic transfusion have been extensively investigated. In this systematic review, we revised the literature concerning the use of UCB for either autologous or allogeneic transfusion purposes and we illustrated the rationale for a transfusion therapy tailored to extremely preterm neonates, based on RBC concentrates from allogeneic UCB donations.

Red blood cell transfusion in infants and children - Current perspectives

Children routinely receive packed red blood transfusion when they are admitted in the intensive care unit or undergoing cardiac surgeries. These guidelines aim to summarize literature and provide transfusion triggers exclusively in infants and children.

Prevention of the anaemia of prematurity

Despite recent advances in neonatal and perinatal medicine, extremely low birth weight infants (ELBW) are at high risk of developing anaemia of prematurity (AOP) requiring packed red blood cell (RBC) transfusions. The benefit of transfusing allogenic RBCs for AOP is a controversial issue, except for disturbances in tissue oxygenation. Although the role of erythropoietin (EPO) in the pathophysiology of AOP is well known, neither early nor late recombinant human EPO therapy alters the number or volume of RBC transfusions. It is also known that one-half of the feto-placental blood volume remains outside the newborn infant's circulation at 30 weeks of gestation if the umbilical cord is clamped immediately. Delayed cord clamping (DCC) and umbilical cord milking (UCM) are the main methods for enhancing placental transfusion. The basic principle of these approaches depends on providing high haemoglobin (Hb) levels to premature infants in the delivery room. The enhancement of placental transfusion clearly results in higher Hb levels at birth, reducing the need for RBC transfusions as well as creating a better haemodynamic status during the initial hours of life. To date, enhancement of placental transfusion in the delivery room by either DCC or UCM seems to be the best preventive measure for AOP. Yet, studies on the associated neurodevelopmental outcomes are insufficient to reach a conclusion. This review summarizes the pathophysiology, treatment and preventative strategies of anaemia of prematurity in light of the current literature.

Allogeneic umbilical cord blood red cell concentrates: an innovative blood product for transfusion therapy of preterm infants

BACKGROUND

Preterm infants often receive blood transfusions early in life. In this setting, umbilical cord blood (UCB) might be safer than adult blood (A) with respect to infectious and immunologic threats.

OBJECTIVES

To evaluate, as a first objective, the feasibility of fulfilling transfusion needs of preterm infants with allogeneic UCB red blood cell (RBC) concentrates and, as a secondary objective, to assess the safety of allogeneic cord blood transfusions.

METHODS

At the Neonatal Intensive Care Unit and the UNICATT Cord Blood Bank of 'A. Gemelli' Hospital in Rome, a prospective study was carried out over a 1-year period, enrolling newborns with gestational age ≤30 weeks and/or birth weight ≤1,500 g requiring RBC transfusions within the first 28 days of life. At first transfusion, patients were assigned to receive UCB-RBCs or A-RBCs depending on the availability of ABO-Rh(D)-matched UCB-RBC units. The same regimen (UCB-RBC or A-RBC units) was thereafter maintained, unless ABO-Rh(D)-matched UCB-RBC units were not available.

RESULTS

Overall, 23 UCB-RBC units were transfused to 9 patients; the requests for UCB-RBC units were met in 45% of patients at the first transfusion and in 78% at the subsequent transfusions. At a median follow-up of 57 days (range 6-219), no acute or delayed transfusion-related adverse events occurred. Hematocrit gain after transfusion and time intervals between transfusions were similar in the UCB-RBC and A-RBC group, as well.

CONCLUSIONS

Transfusing allogeneic UCB-RBC units in preterm infants appears a feasible and safe approach, although the transfusion needs of our study population were not completely covered. More data are necessary to validate this novel transfusion practice.

Osmotic tolerance limits of red blood cells from umbilical cord blood

Effective methods for long-term preservation of cord red blood cells (RBCs) are needed to ensure a readily available supply of RBCs to treat fetal and neonatal anemia. Cryopreservation is a potential long-term storage strategy for maintaining the quality of cord RBCs for the use in intrauterine and neonatal transfusion. However, during cryopreservation, cells are subjected to damaging osmotic stresses during cryoprotectant addition and removal and freezing and thawing that require knowledge of osmotic tolerance limits in order to optimize the preservation process. The objective of this study was to characterize the osmotic tolerance limits of cord RBCs in conditions relevant to cryopreservation, and compare the results to the osmotic tolerance limits of adult RBCs. Osmotic tolerance limits were determined by exposing RBCs to solutions of different concentrations to induce a range of osmotic volume changes. Three treatment groups of adult and cord RBCs were tested: (1) isotonic saline, (2) 40% w/v glycerol, and (3) frozen-thawed RBCs in 40% w/v glycerol. We show that cord RBCs are more sensitive to shrinkage and swelling than adult RBCs, indicating that osmotic tolerance limits should be considered when adding and removing cryoprotectants. In addition, freezing and thawing resulted in both cord and adult RBCs becoming more sensitive to post-thaw swelling requiring that glycerol removal procedures for both cell types ensure that cell volume excursions are maintained below 1.7 times the isotonic osmotically active volume to attain good post-wash cell recovery. Our results will help inform the development of optimized cryopreservation protocol for cord RBCs.

Measurement of posttransfusion red cell survival with the biotin label

The goal of this review is to summarize and critically assess information concerning the biotin method to label red blood cells (RBC) for use in studies of RBC and transfusion biology-information that will prove useful to a broad audience of clinicians and scientists. A review of RBC biology, with emphasis on RBC senescence and in vivo survival, is included, followed by an analysis of the advantages and disadvantages of biotin-labeled RBC (BioRBC) for measuring circulating RBC volume, posttransfusion RBC recovery, RBC life span, and RBC age-dependent properties. The advantages of BioRBC over (51)Cr RBC labeling, the current reference method, are discussed. Because the biotin method is straightforward and robust, including the ability to follow the entire life spans of multiple RBC populations concurrently in the same subject, BioRBC offers distinct advantages for studying RBC biology and physiology, particularly RBC survival. The method for biotin labeling, validation of the method, and application of BioRBCs to studies of sickle cell disease, diabetes, and anemia of prematurity are reviewed. Studies documenting the safe use of BioRBC are reviewed; unanswered questions requiring future studies, remaining concerns, and regulatory barriers to broader application of BioRBC including adoption as a new reference method are also presented.

Recent advances toward defining the benefits and risks of erythrocyte transfusions in neonates

Like many treatments available to small or ill neonates, erythrocyte transfusions carry both benefits and risks. This review examines recent publications aimed at better defining those benefits and those risks, as means of advancing evidence-based neonatal intensive care unit transfusion practices. Since decisions regarding whether to not to order an erythrocyte transfusion are based, in part, on the neonate's blood haemoglobin concentration, the authors also review recent studies aimed at preventing the haemoglobin from falling to a point where a transfusion is considered.

Exploring the use of expanded erythroid cells for autologous transfusion for anemia of prematurity

BACKGROUND

Autologous cord blood (CB) red blood cells (RBCs) can partly substitute transfusion needs in premature infants suffering from anemia. To explore whether expanded CB cells could provide additional autologous cells suitable for transfusion, we set up a simple one-step protocol to expand premature CB cells.

STUDY DESIGN AND METHODS

CB buffy coat cells and isolated CD34-positive (CD34(pos) ) cells from premature and full-term CB and adult blood were tested with several combinations of growth factors while omitting xenogeneic proteins from the culture medium. Cell differentiation was analyzed serially during 21 days using flow cytometry, progenitor assays, and high-performance liquid chromatography.

RESULTS

Expanded CB buffy coat cells resulted in a threefold higher number of erythroblasts than the isolated CD34(pos) cells. However, the RBCs contaminating the buffy coat remained present during the culture with uncertain quality. Premature and full-term CB CD34(pos) cells had similar fold expansion capacity and erythroid differentiation. With the use of interleukin-3, stem cell factor, and erythropoietin, the fold increases of all CD34(pos) cell sources were similar: CB 3942 ± 1554, adult peripheral mobilized blood 4702 ± 1826, and bone marrow (BM) 4143 ± 1908. The proportion of CD235a expression indicating erythroblast presence on Day 21 was slightly higher in the adult CD34(pos) cell sources: peripheral blood stem cells (96.7 ± 0.8%) and BM (98.9 ± 0.5%) compared to CB (87.7 ± 2.7%; p = 0.002). We were not able to induce further erythroid maturation in vitro.

CONCLUSION

This explorative study showed that fairly pure autologous erythroid-expanded cell populations could be obtained by a simple culture method, which should be optimized. Future challenges comprise obtaining ex vivo enucleation of RBCs with the use of a minimal manipulating approach, which can add up to autologous RBCs derived from CB in the treatment of anemia of prematurity.