Foetal haemoglobin, blood transfusion, and retinopathy of prematurity

Progress in the study of association between hematological indicators and retinopathy of prematurity (Review)

Retinopathy of prematurity (ROP) is a retinopathy caused by abnormal proliferation of blood vessels in premature infants. It can lead to retinal detachment and, in severe cases, blindness, rendering ROP a critical condition. Advances in neonatal medicine have improved survival rates of low birth weight and low gestational age infants. However, this progress has also led to a rise in incidence of ROP. Currently, premature birth, low birth weight and high postpartum oxygen levels are independent risk factors for ROP. Other factors include mode of delivery, multiple births, anemia, blood transfusion, maternal pregnancy factors, neonatal bronchopulmonary dysplasia, use of surfactants, arterial ductus arteriosus and necrotizing enterocolitis. Laboratory indicators in premature infants such as platelet count, levels of blood glucose, inflammatory cells, lipid and hemoglobin and blood transfusion may also be associated with ROP. However, the etiology and pathogenesis of ROP are not fully understood. A number of factors may influence the onset and progression of ROP, including decreased platelet counts, decreased hemoglobin levels, increased white blood cell counts, increased blood glucose levels, and disorders of lipid metabolism. The present study reviewed the effects of platelet count, hemoglobin, blood glucose, inflammatory cells and factors, blood lipids, and plasma metabolic pathways on ROP.

Multi-component cord blood banking: a proof-of-concept international exercise

BACKGROUND

Most public cord blood (CB) banks currently discard more than 80% of umbilical CB units not suitable for hemopoietic stem cell transplant due to low stem cell count. Although CB platelets, plasma, and red blood cells have been used for experimental allogeneic applications in wound healing, corneal ulcer treatment, and neonatal transfusion, no standard procedures for their preparation have been defined internationally.

MATERIALS AND METHODS

A network of 12 public CB banks in Spain, Italy, Greece, the UK, and Singapore developed a protocol to validate a procedure for the routine production of CB platelet concentrate (CB-PC), CB platelet-poor plasma (CB-PPP), and CB leukoreduced red blood cells (CB-LR-RBC) using locally available equipment and the commercial BioNest ABC and EF medical devices. CB units with >50 mL volume (excluding anticoagulant) and ≥150×109/L platelets were double centrifuged to obtain CB-PC, CB-PPP, and CB-RBC. The CB-RBC were diluted with saline-adenine-glucose-mannitol (SAGM), leukoreduced by filtration, stored at 2-6°C, and tested for hemolysis and potassium (K+) release over 15 days, with gamma irradiation performed on day 14. A set of acceptance criteria was pre-defined. This was for CB-PC: volume ≥5 mL and platelet count 800-1,200×109/L; for CB-PPP: platelet count <50×109/L; and for CB-LR-RBC: volume ≥20 mL, hematocrit 55-65%, residual leukocytes <0.2×106/unit, and hemolysis ≤0.8%.

RESULTS

Eight CB banks completed the validation exercise. Compliance with acceptance criteria was 99% for minimum volume and 86.1% for platelet count in CB-PC, and 90% for platelet count in CB-PPP. Compliance in CB-LR-RBC was 85.7% for minimum volume, 98.9% for residual leukocytes, and 90% for hematocrit. Compliance for hemolysis ≤0.8% decreased from 89.0 to 63.2% from day 0 to 15. K+ release increased from 3.0±1.8 to 25.0±7.0 mmol/L from day 0 to 15, respectively.

DISCUSSION

The MultiCord12 protocol was a useful tool to develop preliminary standardization of CB-PC, CB-PPP, and CB-LR-RBC.

BORN study: a multicenter randomized trial investigating cord blood red blood cell transfusions to reduce the severity of retinopathy of prematurity in extremely low gestational age neonates

BACKGROUND

Extremely low gestational age neonates (ELGANs, i.e., neonates born before 28 weeks of gestation) are at high risk of developing retinopathy of prematurity (ROP), with potential long-life visual impairment. Due to concomitant anemia, ELGANs need repeated red blood cell (RBC) transfusions. These produce a progressive replacement of fetal hemoglobin (HbF) by adult hemoglobin (HbA). Furthermore, a close association exists between low levels of HbF and severe ROP, suggesting that a perturbation of the HbF-mediated oxygen release may derange retinal angiogenesis and promote ROP.

METHODS/DESIGN

BORN (umBilical blOod to tRansfuse preterm Neonates) is a multicenter double-blinded randomized controlled trial in ELGANs, to assess the effect of allogeneic cord blood RBC transfusions (CB-RBCs) on severe ROP development. Recruitment, consent, and randomization take place at 10 neonatology intensive care units (NICUs) of 8 Italian tertiary hospitals. ELGANs with gestational age at birth comprised between 24+0 and 27+6 weeks are randomly allocated into two groups: (1) standard RBC transfusions (adult-RBCs) (control arm) and (2) CB-RBCs (intervention arm). In case of transfusion need, enrolled patients receive transfusions according to the allocation arm, unless an ABO/RhD CB-RBC is unavailable. Nine Italian public CB banks cooperate to make available a suitable amount of CB-RBC units for all participating NICUs. The primary outcome is the incidence of severe ROP (stage 3 or higher) at discharge or 40 weeks of postmenstrual age, which occurs first.

DISCUSSION

BORN is a groundbreaking trial, pioneering a new transfusion approach dedicated to ELGANs at high risk for severe ROP. In previous non-randomized trials, this transfusion approach was proven feasible and able to prevent the HbF decrease in patients requiring multiple transfusions. Should the BORN trial confirm the efficacy of CB-RBCs in reducing ROP severity, this transfusion strategy would become the preferential blood product to be used in severely preterm neonates.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05100212. Registered on October 29, 2021.

Recycling Apparent Waste Into Biologicals: The Case of Umbilical Cord Blood in Italy and Spain

Most public cord blood banking programs are currently facing financial difficulties due to a progressive decline in the number of cord blood transplants performed worldwide and to a high discard rate of the donated units caused by progressively increasing thresholds of the stem cell dose required to perform safe and effective hemopoietic cord blood transplants. Recycling a proportion of unused cord blood units to prepare novel cord blood components obtained with minimal manipulation (platelets, plasma, red blood cells) and to develop more technologically complex products regulated in the US as Cellular and Gene Therapy Products and in Europe as Advanced Therapy Medicinal Products [e.g. virus-specific T cells (VST), natural killer (NK) cells, induced pluripotent stem cells (iPSCs) is a promising strategy to increase the therapeutic value and reduce the financial deficits of public cord blood banking. Based on encouraging preliminary evidences reported in the literature, additional laboratory studies, large multicenter clinical trials and international regulatory harmonization are necessary to achieve these important goals. This article describes organizational, methodological and regulatory advancements developed in Italy and Spain to promote the clinical use of cord blood platelets, plasma and red blood cells.

Low fraction of fetal haemoglobin is associated with retinopathy of prematurity in the very preterm infant

Background

Blood loss and adult blood transfusions are common during the neonatal period in preterm infants. The objective of the study was to clarify if degree of loss of fetal haemoglobin (HbF) was associated with later retinopathy of prematurity (ROP).

Methods

Retrospective observational cohort study. In total, 452 infants born <30 gestational weeks at a tertiary level neonatal intensive care unit in Sweden in 2009–2015 were included, 385 of whom had final ROP outcome. Mean fractions of HbF (%) during the first postnatal week were calculated from 11 861 arterial blood gas analyses. The relationship between fractions of HbF (%) and ROP was evaluated.

Results

The mean (SD) gestational age (GA) at birth was 26.4 (1.8) weeks. In total, 104 (27 %) infants developed ROP. Higher fraction of HbF (%) was associated with a lower prevalence of ROP, OR by a 10% increase 0.83 (95% CI: 0.71 to 0.97; p=0.019), following adjustment for GA at birth, small for GA and sex. Infants with HbF (%) in the lowest quartile had OR of 22.0 (95% CI: 8.1 to 59.2; p<0.001) for ROP development compared with those in the highest quartile. The predictive ability (area under the curve) of HbF (%) in the full model during the first week was 0.849 for ROP.

Conclusions

Early low fraction of HbF is independently associated with abnormal retinal neurovascular development in the very preterm infant. The potential benefit of minimising blood loss on development of ROP will be investigated in a multicenter randomised trial (NCT04239690).

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.