Smoking during pregnancy--hematological observations in the newborn

Hematological values were measured in 28 newborn infants of mothers smoking 10-20 cigarettes daily during pregnancy, and in 25 infants of non-smokers. Higher hematocrit levels were found on the 1st day of life in infants of smoking mothers (60.8 +/- 5.0%, mean +/- S.D.) compared to controls (57.5 +/- 4.8%) (p less than 0.05). The hematocrit levels correlated positively with the maternal smoking level (r = 0.318, p less than 0.05) and the maternal serum thiocyanate concentrations at delivery (r = 0.389, p less than 0.01). Cord serum values for erythropoietin, serum-iron, transferrin and ferritin showed no statistically significant difference between the two groups. A significant inverse correlation was found between the hematocrit value on the 1st day of life and the cord serum ferritin concentration (r = -0.495, p less than 0.005). The present results suggest that maternal smoking stimulates fetal erythropoiesis, probably through a hypoxic effect on the fetus, dose related to the maternal smoking level. Increased erythropoiesis may cause increased iron incorporation into erythrocytes at expense of iron storage in the bone marrow and reticuloendothelial system.     

CELL POPULATIONS IN THE BONE MARROW OF GUINEA PIG FETUSES WITH INTRAUTERINE GROWTH RETARDATION

Bone marrow smears and blood samples were examined in guinea pig fetuses in which intrauterine growth retardation (IUGR) had been induced by uterine artery ligation and compared with those of control (well-grown) fetuses from uterine horns with intact circulation. Differential bone marrow cell counts were obtained from a count of 300 cells per smear and blood samples were assayed for hemoglobin concentration and 2,3-diphosphoglycerate (DPG). Results of blood assays showed no difference in hemoglobin concentration. DPG levels were reduced in the IUGR guinea pigs (.05), which could be a consequence of decreased glucose availability or represent an adaptation to reduced oxygen availability. Comparisons of bone marrow counts revealed an increase in total erythrocyte precursors (.05) and a decrease in total granulocytic precursors (.05) in IUGR fetuses. Within the erythroid lineage there was a significant increase in late (orthochromatic) erythroblasts (.005) in the IUGR animals compared with control animals. The granulocytic lineage of the IUGR fetuses showed a significant decrease in mature neutrophils (.05) and eosinophilic precursors (.05) compared with controls. These data suggest that the hypoxic stress of uterine artery ligation leads to an increase in medullary erythropoiesis. In concert with a previous study that showed a reduction in hepatic erythropoiesis, these data suggest a precocious shift of the anatomic site of erythropoiesis from the liver to the bone marrow under conditions of hypoxia.     

ERYTHROPOIETIN IN PREMATURE INFANTS

ABSTRACT. The regulation of erythropoiesis during the first three months of life was studied in 30 premature infants who had haemoglobin concentrations which were lower than in term infants of the same postdelivery age. Erythropoietin and erythropoiesis inhibitors were measured by means of an exhypoxic polycythaemic mouse bioassay. The percentage of haemoglobin F was determined as well. An increased erythropoietin level was detected only in six infants older than six weeks, whose blood haemoglobin concentration was lower than 100 g/l, while in serum from other babies erythropoietin was undetectable by the method used. Erythropoiesis inhibitors were present in 80% of the samples tested. The results presented indicate that in premature infants erythropoiesis is regulated through erythropoietin and that inhibitors of erythropoiesis take part in this regulation as well, but that the haemoglobin level at which erythropoietin is increased is lower in preterm infants than in term babies.     

Anemia of prematurity: determinants of the erythropoietin response

This study was undertaken to determine the factors that are important in determining the erythropoietin response in low-birth-weight infants during the period of so-called anemia of prematurity. In the first weeks of life oxygen consumption in a group of 21 infants gradually increased as hemoglobin level fell. The magnitude of the erythropoietin response inversely varied with the central venous oxygen tension (P-vO2) (r = -0.55, P less than 0.001). When the P-vO2 declined to less than 30 torr, erythropoietin values were uniformly increased above the "normal" range (defined as the values associated with P-vO2 greater than 38 torr). Erythropoietin values varied inversely with hemoglobin but in general did not exceed the values observed for normal adult men. The erythropoietin values in the infants were remarkably lower at any given hemoglobin level when compared with those of older children with anemia resulting from bone marrow failure. In general, elevations of erythropoietin were seen when the hemoglobin concentration declined to less than 10.0 gm/dl. Change in heart rate did not appear to be a reliable indicator of the presence of anemia; rather, it correlated best with oxygen consumption.     

Erythropoietin in premature infants

The regulation of erythropoiesis during the first three months of life was studied in 30 premature infants who had haemoglobin concentrations which were lower than in term in fants of the same postdelivery age. Erythropoietin and erythropoiesis inhibitors were measured by means of an exhypoxic polycythaemic mouse bioassay. The percentage of haemoglobin F was determined as well. An increased erythropoietin level was detected only in six infants older than six weeks, whose blood haemoglobin concentration was lower than 100 g/l, while in serum from other babies erythropoietin was undetectable by the method used. Erythropoiesis inhibitors were present in 80% of the samples tested. The results presented indicate that in premature infants erythropoiesis is regulated through erythropoietin and that inhibitors of erythropoiesis take part in this regulation as well, but that the haemoglobin level at which erythropoietin is increased is lower in preterm infants than in term babies.     

Iron-deficient erythropoiesis in neonatal rats.

Anemia in premature infants is extremely common. Precise quantitation of iron status and determination of iron incorporation into erythrocytes are important in monitoring therapy for anemia in premature infants, especially when treating with recombinant human erythropoietin (rhEPO). However, the traditional indices of the iron status have limited usefulness in this population. The goal of the current work is to develop an experimental animal model system that addresses the clinical issue relating to quantitation of iron delivery to erythrocytes. We first determined normal hematological values for nontreated, dam-suckled Sprague-Dawley rats by measuring markers of erythropoiesis and iron status during the first 12 postnatal days (PND). The experimental group of rats were administered parenteral rhEpo (430 IU.kg(-1). day(-1)) for 8 days (from PND 4 until PND 12) in the absence (rhEpo(-Fe)) or presence (rhEpo(+Fe)) of oral iron supplementation (6 mg.kg(-1).day(-1)). Rat pups receiving oral iron only (control(+Fe)) and pups that were sham fed with the orogastric tube (control(-Fe)) were included as controls. Hematological parameters were measured in blood and bone marrow. In a pattern similar to that seen in premature infants during the first 2 months of life, the levels of these hematopoietic markers were dynamic and changed during the first 12 PND. After challenging experimental animals with subcutaneous rhEpo, evidence of iron-deficient erythropoiesis was seen in the rhEpo(-Fe) group. Red blood cell levels and absolute reticulocyte counts were higher in both groups receiving rhEpo as compared with the controls. However, the rhEpo(-Fe) group experienced a lower hemoglobin level, a lower mean red cell volume, a greater red cell distribution width, and a higher zinc protoporphyrin/heme (ratio than the rhEpo(+Fe) group. The neonatal rat is an excellent model of iron-deficient erythropoiesis and will be useful in designing future mechanistic studies examining the interplay between iron and erythropoiesis in the anemic, iron-challenged premature neonate.     

Erythropoietin to prevent and treat the anemia of prematurity

Human recombinant erythropoietin was first cloned in 1985, and is currently available for clinical use for a variety of anemias. Following successful clinical trials using erythropoietin to treat adults with the anemia of end-stage renal disease, the first clinical trial evaluating the use of erythropoietin in preterm infants to treat anemia was published in 1990. Since that initial report, numerous clinical trials have reported various levels of success in the treatment of this anemia. Most recently, erythropoietin has been used in the first weeks of life in an attempt to prevent the anemia of prematurity. This review describes mechanisms of erythropoiesis in the fetus and neonate, and focuses on recent clinical trials evaluating the use of erythropoietin to prevent and treat anemia in preterm infants.     

Childhood hypoplastic anemia with sugar chain anomaly of red cell membranes

Abstract Background : Childhood hypoplastic anemia of unknown etiology had not existed until now. To assess pathophysiological differentiation in childhood hypoplastic anemia, we analyzed red cell membrane components in six children with hypoplastic anemia of unknown etiology.
Methods : The six children all had chronic moderate anemia and thrombocytopenia. They also showed hypoplastic marrow cellularity with erythroblastopenia, megakaryocytopenia, and mild morphological anomalies (pelger Hëut anomaly of neutrophils and bi- or trinuclear erythroblasts), except for one child who had normal platelets and megakaryocytes. Red blood cells of patients and several anemic children, cord blood and healthy controls were analyzed by the peanut lectin agglutination (PNA) test, flow cytometry, sodium dodecyl sulfate_polyacrylamide gel electrophoresis of membrane proteins, high performance liquid chromatography (HPLC) of sugar chains and the colony-forming assay of bone marrow erythroblasts.
Results : In the six children, the PNA agglutination test showed a persistent positive reaction not only for peripheral red blood cells but also for bone marrow erythroblasts. This was not observed in other anemic children and healthy controls. With HPLC analysis, the sugar chains of red blood cell membranes showed the loss of sialic acid from O-linked oligosaccharides.
Conclusions : Our results suggested that the abnormality of red blood cells from these patients was attributable to abnormal surface sugar chains (loss of sialic acid from O-glycan), which are already present at the erythroblast stage in the bone marrow and that may be responsible for a group of anemias.     

PLASMA ERYTHROPOIETIN CONCENTRATIONS DURING THE EARLY ANEMIA OF PREMATURITY

ABSTRACT. Plasma erythropoietin concentrations were studied in 11 preterm appropriate for gestational age infants at the age of 3-14 weeks. Their birth weights ranged from 860-1690 g. Erythropoietin was measured by a cell culture technique. Significant concentrations of erythropoietin was detected in 18 out of 29 samples, at all stages of the early anemia. The highest levels were found at 3-9 weeks. Individual erythropoietin values did not correlate with hemoglobin concentrations, hematocrit levels or 'corrected' reticulocyte counts, nor did the 'corrected' reticulocyte count correlate with hemoglobin or hematocrit. The lack of correlation with hemoglobin concentration most likely reflects the importance of other factors as well as the hemoglobin in determining the oxygenation status of the infant. A significant positive correlation ( r =0.60, p <0.01) was found between erythropoietin concentration and weight gain in the preceding week. The study shows that small preterm infants are capable of erythropoietin production during their early anemia, and indicates that the hormone plays a role in the regulation of erythropoiesis also at this time of life.     

SMOKING DURING PREGNANCY—HEMATOLOGICAL OBSERVATIONS IN THE NEWBORN

ABSTRACT. Meberg, A., Hågå, P., Sande, H. and Foss, O. P. (Departments of Paediatrics, Obstetrics and Gynaecology, Clinical Chemistry and Pathology, Ullevål Hospital, Oslo, Norway). Smoking during pregnancy—hematological observations in the newborn. Acta Paediatr Scand, 68: 731, 1979.—Hematological values were measured in 28 newborn infants of mothers smoking 10–20 cigarettes daily during pregnancy, and in 25 infants of non-smokers. Higher hematocrit levels were found on the 1st day of life in infants of smoking mothers (60.8±5.0%, mean ±S.D.) compared to controls (57.5±4.8%) (p<0.05). The hematocrit levels correlated positively with the maternal smoking level (r=0.318, p<0.05) and the maternal serum thiocyanate concentrations at delivery (r=0.389, p<0.01). Cord serum values for erythropoietin, serum-iron, transferrin and ferritin showed no statistically significant difference between the two groups. A significant inverse correlation was found between the hematocrit value on the 1st day of life and the cord serum ferritin concentration (r=–0.495, p<0.005). The present results suggest that maternal smoking stimulates fetal erythropoiesis, probably through a hypoxic effect on the fetus, dose related to the maternal smoking level. Increased erythropoiesis may cause increased iron incorporation into erythrocytes at expense of iron storage in the bone marrow and reticuloendothelial system.     

A paediatric case of sideroblastic anaemia

We examined the morphological and functional characteristics of erythroblasts derived from marrow erythroid progenitor cells grown in a methylcellulose microculture, which were taken from a female child with rate atypical sideroblastic anaemia (SA) partially responsive to pyridoxine. Colony formation was within the normal range in three successive cultures (median values: 82.25 CFU-E and 16.4 BFU-E derived colonies/6.6×10⁴ cells) compared to growth by normal cells (65-315 CFU-E and 9-40 BFU-E). We evaluated in vitro differentiation by biochemical microassay of a cytosol enzyme involved in the haeme pathway: uroporphyrinogen I synthase (UROS). The UROS values in the erythroid colonies from SA marrow were at the lower end of the normal range (median values: 6.7±0.3 and 14.4±3.8 pmol uroporphyrinogen/h in CFU-E and BFU-E-derived colonies respectively versus 17.4±7.3 and 25±7.2 pmol/h in CFU-E and BFU-E colonies from normal subjects.Ultrastructural examination of the SA erythroblasts from non-cultured bone marrow or derived from cultured BFU-E revealed the characteristic deposition of iron in mitochondria around the nucleus of most cells (ringed sideroblasts). However, the majority of cultured cells had marked dyserythropoietic featuress, with a large number of bilobulated or trilobulated crythroblasts, multiple cytoplasmic vacuoles, numerous abnormalities of the nucleus, and excessive membrane material beneath the plasma membrane, all features difficult to observe in non-cultured marrows.Abbreviations SA sideroblastic anaemia - UROS uroporphyrinogen I synthase - BFU-E erythroid burst-forming units - CFU-E colony-forming units - EPO erythropoietin - CDA congenital dyserythropoietic anaemia     

The biochemical and hematological assessment of iron metabolism]

Despite the progress in the knowledge of iron metabolism, its precise assessment remains uneasy. Serum ferritin assesses the extent of storage iron. Serum iron and the percentage of transferrin saturation evaluate the tissues' iron supply. But these parameters are indirect measurements and they do not reflect marrow iron supply. Serum transferrin receptors, red cell ferritin and red cell zinc protoporphyrin are good indicators of this iron supply to the erythroid marrow for erythropoiesis. Since the introduction of recombinant human erythropoietin, it has become apparent that an adequate iron supply to the bone marrow is essential for a satisfactory hematopoietic response. In some cases, despite a high baseline ferritin, iron may not be sufficiently released from reserves in the bone marrow, resulting in a functional iron deficiency. The percentage of hypochromic red cells and reticulocyte haemoglobin content tends to reflect direct marrow iron status.     

小儿再生障碍性贫血的诊断及鉴别诊断

目的提高对小儿再生障碍性贫血(AA)诊断及鉴别诊断的认识。方法对30例CAA、17例骨髓增生异常综合征(MDS)及4例小儿急性淋巴细胞白血病前期(pre-ALL)做血象、骨髓象及骨髓活检分析。结果CAA组与MDS组血象单核细胞及血小板计数间比较(P<0·05),有显著性差异。CAA组骨髓增生低下,原始+早幼粒细胞、原始+早幼红细胞、巨核细胞明显少于MDS,各组间比较(P<0·01),有显著差异性,并见MDS各系病态造血。骨髓活检CAA组96%以上造血组织明显减少、脂肪组织明显增多,巨核细胞缺如或减少(均<2个/片),检出率9·7%,纤维组织增生检出率16·3%。MDS组70%增生良好,近60%检出红系同一阶段发育幼红细胞岛,近90%检出幼稚前体细胞异常定位(ALIP),全部病例见纤维组织增生和小巨核细胞等异常。4例pre-ALL示三系细胞减少,骨髓增生减低,巨核细胞0~6个/片,活检示脂肪组织增多,造血组织明显减少,亦可见病态造血,1~4周内转变为急性淋巴细胞白血病(ALL)。结论CAA患儿外周血细胞减少,骨髓造血功能衰竭,无病态造血。MDS外周血单核细胞增多,骨髓增生良好,具有多系病态造血;ALIP、巨核细胞形态异常及红系同一阶段发育幼红细胞岛伴纤维组织增生是其特征。pre-ALL具有CAA和MDS的临床及实验室特点,但在短期内转变为ALL又与之不同。     

Treatment of refractory aplastic anemia with plasmapheresis: report of a case in childhood with review of the literature

Treatment of aplastic anemia may raise considerable problems in some patients. This report concerns a boy whose illness started at 11 years of age. At first admission laboratory data were: hemoglobin 7.5 g/l, and counts of leucocytes, neutrophils and platelets were 2.3, 0.6, and 8 x 10(9)/l, respectively. His bone marrow was hypoplastic with sparse erythropoiesis. The patient did not respond to traditional medical treatment. Serum contained a high concentration of erythropoietin but no antibodies against erythropoietin. The patient's serum did neither alone, nor supported with recombinant erythropoietin, stimulate erythropoiesis in a bioassay, suggesting that some factor(s) inhibiting erythropoietic activity was present. Based on this hypothesis, plasma exchange was performed. After 26 weeks of plasmapheresis the hematological parameters were normalized. We conclude that plasmapheresis might be an alternative in treatment of resistant aplastic anemia. Further diagnostic tools to identify patients who might benefit from such a treatment are required.     

Anemia of prematurity: progress and prospects

Recombinant human erythropoietin (r-HuEPO) is of interest to pediatric hematologists and neonatologists because it may prove to be an effective alternative to blood transfusions in preventing and treating anemia in premature infants. The anemia of prematurity is the most promising setting for initial clinical trials. However, it is conceivable that recombinant erythropoietin will be given at birth to low-birth-weight infants in an effort to stimulate endogenous erythropoiesis and thereby prevent some of the erythrocyte transfusions required to replace blood sampled for laboratory tests. Beyond its appeal as a therapeutic alternative to red blood cell transfusions, recombinant human erythropoietin is likely to be the first member of an entirely new class of drugs to be used widely in neonatal medicine. These are drugs produced by cloning normal human genes and expressing them in the laboratory. Because many of the problems of premature birth are caused by developmental immaturity, transiently replacing crucial proteins with exact copies produced by the techniques of recombinant DNA technology is an approach that may have a major impact on morbidity and mortality of neonates. Carefully designed, controlled clinical trials will be essential to determine the role of new agents like r-HuEPO in the treatment of medical problems of premature infants.     

Effects of erythropoietin on erythrocyte deformability in non-transfused preterm infants

AIM: Suppression of erythropoiesis due to low plasma erythropoietin levels is an important factor in the development of anaemia of prematurity. Premature infants may therefore be treated with recombinant human erythropoietin (rhEPO). This prospective, randomised and controlled study was designed to find out whether rhEPO treatment improves erythrocyte deformability in preterm infants. METHODS: Sixteen infants were treated with rhEPO (250 IU/kg three times weekly) a total of 15 times beginning on day of life 5 whereas fifteen infants served as controls. Haemoglobin concentration, haematocrit, reticulocyte count, ferritin level and erythrocyte deformability were measured on days 5, 14, 28, 42 and 63. Erythrocyte elongation was determined as an indicator of erythrocyte deformability using a shear stress diffractometer (Rheodyn SSD) at shear forces of 0.3 to 60 Pa. RESULTS: Haemoglobin concentration was significantly higher on days 28 and 42 and reticulocyte percentage on day 28 in the rhEPO group compared to the controls. Serum ferritin was lower in the rhEPO group on day 28. Erythrocyte deformability was significantly increased on days 28 and 42 in the infants receiving rhEPO. We found a strong relationship between erythrocyte elongation and reticulocyte count. CONCLUSION: RhEPO markedly increases the erythropoiesis in preterm infants in the critical first weeks of life and the anaemia of prematurity is obviously reduced. The erythrocyte deformability improved under rhEPO treatment. Erythrocyte deformability was significantly related to the reticulocyte count indicating that the improvement of erythrocyte deformability was due to the formation of well-deformable young erythrocytes.     

URINARY EXCRETION OF ERYTHROPOIETIN AND ERYTHROPOIESIS INHIBITORS IN THE NEONATAL PERIOD

ABSTRACT. Lindemann, R. (Pediatric Research Institute, Department of Pediatrics, University Hospital, Rikshospitalet, Oslo, Norway). Urinary excretion of erythropoietin and erythropoiesis inhibitors in the neonatal period. Acta Paediatr Scand, 63:764, 1974. —The regulation and suppression of erythropoiesis in the neonatal period has been studied. Urines from normal newborn babies were collected from time of delivery and during the first week of life. Both erythropoietin (ESF) and an erythropoiesis inhibiting factor (EIF) were separated by Sephadex gel filtration. The factors were tested according to days after birth and related to the creatinine coefficient. The exhypoxic polycythemic mouse bioassay was used and the results were expressed as the per cent incorporation of ⁵⁹Fe into newly formed red blood cells. A demonstrable amount of ESF was found only in the urine voided the first day of life, indicating that the ESF production is shut off immediately after birth. From the third day of Life, a marked inhibitory effect of the EIF fractions was found. This may indicate a dual mechanism behind the decrease in neonatal erythropoiesis: a shut off of the ESF production and the appearence of erythropoiesis inhibitors.     

Lack of correlation between free erythrocyte porphyrin and serum ferritin values at birth and at 2 months of life in low birthweight infants

Red cell free erythrocyte porphyrin and serum ferritin determinations were performed on capillary blood specimens from 63 healthy infants weighing 2500 g or less at birth, during the first week of life, and, from 44 of them, again at 8-10 weeks. Free erythrocyte porphyrin values were high both at 3-7 days (mean 156 microgram/100 ml RBC) and at 8-10 weeks (mean 128 microgram/100 ml RBC). The respective serum ferritin values were also high (mean 226 and 107 ng/ml), excluding a depletion in iron stores. In addition, no correlation was found between free erythrocyte porphyrin and serum ferritin values either at birth or at age 2 months. These findings are consistent with an earlier hypothesis that in the presence of iron stores, the rate of iron release from the stores in low birthweight infants may not be sufficient to maintain optimal erythropoiesis if the demand is accelerated.     

Lack of correlation between free erythrocyte porphyrin and serum ferritin values at birth and at 2 months of life in low birthweight infants.

Red cell free erythrocyte porphyrin and serum ferritin determinations were performed on capillary blood specimens from 63 healthy infants weighing 2500 g or less at birth, during the first week of life, and, from 44 of them, again at 8-10 weeks. Free erythrocyte porphyrin values were high both at 3-7 days (mean 156 microgram/100 ml RBC) and at 8-10 weeks (mean 128 microgram/100 ml RBC). The respective serum ferritin values were also high (mean 226 and 107 ng/ml), excluding a depletion in iron stores. In addition, no correlation was found between free erythrocyte porphyrin and serum ferritin values either at birth or at age 2 months. These findings are consistent with an earlier hypothesis that in the presence of iron stores, the rate of iron release from the stores in low birthweight infants may not be sufficient to maintain optimal erythropoiesis if the demand is accelerated.     

Severe congenital leukopenia (reticular dysgenesis). Immunologic and morphologic characterizations of leukocytes

We report fatal reticular dysgenesis in a premature infant presenting with severely decreased blood and bone marrow granulocytes and lymphocytes, an absent thymic shadow by x-ray film, and generalized lymphoid hypoplasia. Immunologic and electron microscopic evaluation of his white blood cells demonstrated that, despite extremely low cell numbers, cells from all stages of both granulocytic and lymphocytic development were present. Immature bone marrow cells of both myeloid and lymphoid lineages were found in much greater proportions than were mature cells; pre-B cells outnumbered B cells by more than tenfold. Megakaryocytes and erythroid cells appeared to be present in normal numbers, and tritiated-thymidine incorporation by bone marrow nucleated cells was also normal, although it may have largely occurred in erythroblasts. These data suggest that the primary defect in reticular dysgenesis is not failure in initiation of stem cell differentiation along lymphoid and myelomonocytic lines but rather an, as yet, undefined abnormality that interferes with normal growth and maturation of immune cells committed to these differentiation pathways.