Effect of cord blood processing on transplantation outcomes after single myeloablative umbilical cord blood transplantation.

Variations in cord blood manufacturing and administration are common, and the optimal practice is not known. We compared processing and banking practices at 16 public cord blood banks (CBB) in the United States and assessed transplantation outcomes on 530 single umbilical cord blood (UCB) myeloablative transplantations for hematologic malignancies facilitated by these banks. UCB banking practices were separated into 3 mutually exclusive groups based on whether processing was automated or manual, units were plasma and red blood cell reduced, or buffy coat production method or plasma reduced. Compared with the automated processing system for units, the day 28 neutrophil recovery was significantly lower after transplantation of units that were manually processed and plasma reduced (red cell replete) (odds ratio, .19; P = .001) or plasma and red cell reduced (odds ratio, .54; P = .05). Day 100 survival did not differ by CBB. However, day 100 survival was better with units that were thawed with the dextran-albumin wash method compared with the "no wash" or "dilution only" techniques (odds ratio, 1.82; P = .04). In conclusion, CBB processing has no significant effect on early (day 100) survival despite differences in kinetics of neutrophil recovery.

Transfusion-related acute gut injury: necrotizing enterocolitis in very low birth weight neonates after packed red blood cell transfusion.

OBJECTIVE: This is a repeat cohort study in which we sought to determine whether an association of necrotizing enterocolitis (NEC) <48 hours of a packed red blood cells (PRBC) transfusion was a prior sampling artifact. STUDY DESIGN: All very low birth weight neonates with NEC Stage ≥ IIB admitted over an 18-month period were categorized for NEC: (1) <48 hours after a PRBC transfusion; (2) unrelated to the timing of PRBCs; and (3) never transfused. RESULTS: Eight hundred eighty-three admissions over 18 months were reviewed; 256 were very low birth weight that resulted in 36 NEC cases and 25% were associated with PRBC (n = 9). PRBC-associated cases had lower birth weight, hematocrit, and rapid onset of signs (<5 hours). The timing of association of PRBC transfusion and NEC differed from random, showing a distribution that was not uniform over time (χ(2) = 170.7, df = 40; P < .000001) consistent with the possibility of a causative relationship in certain cases of NEC. Current weight at onset of NEC did not differ; however, the more immature the neonate the later the onset of NEC creating a curious centering of occurrence at a median of 31 weeks postconceptual age. CONCLUSIONS: We conclude that PRBC-related NEC exists. Transfusion-related acute gut injury is an acronym we propose to characterize a severe neonatal gastrointestinal reaction proximal to a transfusion of PRBCs for anemia. The convergence at 31 weeks postconceptual age approximates the age of presentation of other O(2) delivery and neovascularization syndromes, suggesting a link to a generalized systemic maturational mechanism.

A randomized phase II trial of Arginine Butyrate with standard local therapy in refractory sickle cell leg ulcers.

Sickle cell leg ulcers are often debilitating, refractory to healing, and prone to recurrence. Healing of leg ulcers was incidentally observed during dose-ranging trials of Arginine Butyrate in beta haemoglobinopathies. Here, a controlled Phase II trial was performed in sickle cell patients who had lower extremity ulcers refractory to standard care for at least 6 months. Patients were randomized to receive standard local care alone (Control Arm) or standard care with Arginine Butyrate administered 5 d/week (Treatment Arm), for 12 weeks. Ulcers were photographed weekly, traced, and ulcer areas were calculated by computerized planimetry and compared between the two study arms. Twenty-seven study courses were evaluated. Control Arm subjects had 25 ulcers with a mean area of 25·7 cm(2) initially and 23·2 cm(2) after 12 weeks; 2/25 (8%) healed completely. Treatment Arm subjects had 37 ulcers with a mean area of 50·6 cm(2) initially and 28·3 cm(2) at 12 weeks; 11/37 of these (30%) healed completely. After 3 months, proportions of ulcers which healed were 6/25 (24%) and 29/37 (78%), in the Control and Treatment Arms respectively (P < 0·001). These findings strongly suggest that Arginine Butyrate merits further evaluation for the treatment of refractory sickle cell leg ulcers in larger trials.

Role of epigenetic modifications in normal globin gene regulation and butyrate-mediated induction of fetal hemoglobin.

Butyrate is a prototype of histone deacetylase inhibitors that is believed to reactivate silent genes by inducing epigenetic modifications. Although butyrate was shown to induce fetal hemoglobin (HbF) production in patients with hemoglobin disorders, the mechanism of this induction has not been fully elucidated. Our studies of the epigenetic configuration of the beta-globin cluster suggest that DNA methylation and histone H3 acetylation are important for the regulation of developmental stage-specific expression of the beta-like globin genes, whereas acetylation of both histones H3 and H4 seem to be important for the regulation of tissue-specific expression. These studies suggest that DNA methylation may be important for the silencing of the beta-like globin genes in nonerythroid hematopoietic cells but may not be necessary for their silencing in nonhematopoietic cells. Furthermore, our studies demonstrate that butyrate exposure results in a true reversal of the normal developmental switch from gamma- to beta-globin expression. This is associated with increased histone acetylation and decreased DNA methylation of the gamma-globin genes, with opposite changes in the beta-globin gene. These studies provide strong support for the role of epigenetic modifications in the normal developmental and tissue-specific regulation of globin gene expression and in the butyrate-mediated pharmacologic induction of HbF production.

Pharmacological induction of fetal hemoglobin: Why haven't we been more successful in thalassemia?

The first studies of the pharmacological induction of fetal hemoglobin were conducted in patients with sickle cell disease and thalassemia. Although hydroxyurea was approved by the FDA for the treatment of sickle cell disease in 1996, no similar pharmacological agent(s) has been approved for the treatment of patients with thalassemic disorders. The small-scale studies of the induction of fetal hemoglobin in thalassemia have been generally disappointing. The aim of this report is to provide a critical analysis of the factors that may be responsible for our failure to develop an effective fetal hemoglobin induction therapy for patients with thalassemia. We also describe several areas for future investigation that may be critically important for the development of an effective therapy for thalassemia.

Butyrate increases the efficiency of translation of gamma-globin mRNA.

Fetal hemoglobin (Hb F) levels increase in most patients with sickle cell disease following intermittent butyrate therapy. Although the full effects of butyrate on Hb F levels usually require multiple treatment cycles, in some patients a peak level is achieved after a few days of butyrate therapy. Our investigation of the mechanism(s) responsible for this rapid induction of Hb F by butyrate showed that reticulocyte gamma-globin chain synthesis markedly increased within 24 hours of butyrate exposure, without concomitant changes in reticulocyte gamma-globin mRNA levels. This suggests that butyrate might induce Hb F by increasing the efficiency of translation of gamma-globin mRNA. This hypothesis was confirmed by ribosome loading studies that demonstrated enrichment of the polysomal fraction of reticulocytes with gamma-globin mRNA following butyrate exposure. Thus, the induction of Hb F by butyrate may be mediated by translational effects in addition to its well-known effects on transcription of the gamma-globin genes.