Human umbilical cord cells: a new cell source for cardiovascular tissue engineering

BACKGROUND

Tissue engineering of viable, autologous cardiovascular constructs with the potential to grow, repair, and remodel represents a promising new concept for cardiac surgery, especially for pediatric patients. Currently, vascular myofibroblast cells (VC) represent an established cell source for cardiovascular tissue engineering. Cell isolation requires the invasive harvesting of venous or arterial vessel segments before scaffold seeding, a technique that may not be preferable, particularly in pediatric patients. In this study, we investigated the feasibility of using umbilical cord cells (UCC) as an alternative autologous cell source for cardiovascular tissue engineering.

METHODS

Human UCC were isolated from umbilical cord segments and expanded in culture. The cells were sequentially seeded on bioabsorbable copolymer patches (n = 5) and grown in vitro in laminar flow for 14 days. The UCC were characterized by flow cytometry (FACS), histology, immunohistochemistry, and proliferation assays and were compared to saphenous vein-derived VC. Morphologic analysis of the UCC-seeded copolymer patches included histology and both transmission and scanning electron microscopy. Characterization of the extracellular matrix was performed by immunohistochemistry and quantitative extracellular matrix protein assays. The tissue-engineered UCC patches were biomechanically evaluated using uniaxial stress testing and were compared to native tissue.

RESULTS

We found that isolated UCC show a fibroblast-like morphology and superior cell growth compared to VC. Phenotype analysis revealed positive signals for alpha-smooth muscle actin (ASMA), desmin, and vimentin. Histology and immunohistochemistry of seeded polymers showed layered tissue formation containing collagen I, III, and glycoaminoglycans. Transmission electron microscopy showed viable myofibroblasts and the deposition of collagen fibrils. A confluent tissue surface was observed during scanning electron microscopy. Glycoaminoglycan content did not reach values of native tissue, whereas cell content was increased. The biomechanical properties of the tissue-engineered constructs approached native tissue values.

CONCLUSIONS

Tissue engineering of cardiovascular constructs using UCC is feasible in an in vitro environment. The UCC demonstrated excellent growth properties and tissue formation with mechanical properties approaching native tissue. It appears that UCC represent a promising alternative autologous cell source for cardiovascular tissue engineering, offering the additional benefits of using juvenile cells and avoiding the invasive harvesting of intact vascular structures.

Parenteral iron therapy in obstetrics: 8 years experience with iron-sucrose complex

Fe is an essential component of haem in myoglobin and accounts for 70 % of haemoglobin. The balance of Fe, unlike that of other metals such as Na or Ca, is regulated solely by gastrointestinal absorption, which itself depends on the bioavailability of Fe in food, i.e. the chemical Fe species. Factors that maintain Fe homeostasis by modulating Fe transfer through the intestinal mucosa are found at the luminal, mucosal and systemic levels. Fe deficiency and its consequence, Fe-deficiency anaemia, form the commonest nutritional pathology in pregnant women. The current gold standard to detect Fe deficiency remains the serum ferritin value. Previously there was general consensus against parenteral Fe administration, i.e. parenteral Fe was only recommended for special conditions such as unresponsiveness to oral Fe, intolerance to oral Fe, severe anaemia, lack of time for therapy etc. However, especially in hospital settings, clinicians regularly face these conditions but are still worried about reactions that were described using Fe preparations such as Fe-dextrans. A widely used and safe alternative is the Fe-sucrose complex, which has become of major interest to prevent functional Fe deficiency after use of recombinant erythropoietin Numerous reports show the effectiveness and safety of the Fe-sucrose complex. Good tolerance to this Fe formulation is partly due to the low allergenic effect of the sucrose complex, partly due to slow release of elementary Fe from the complex. Accumulation of Fe-sucrose in parenchyma of organs is low compared with Fe-dextrans or Fe-gluconate, while incorporation into the bone marrow for erythropoiesis is considerably faster. Oral Fe is only started if haemoglobin levels are below 110 g/l. If levels fall below 100 g/l or are below 100 g/l at time of diagnosis, parenteral Fe-sucrose is used primarily. In cases of severe anaemia (haemoglobin <90 g/l) or non-response to parenteral Fe after 2 weeks, recombinant erythropoietin is considered in combination. By using parenteral Fe-sucrose in cases of severe Fe deficiency, anaemia during pregnancy is treated efficiently and safely according to our results and rate of blood transfusion could be reduced considerably to below 1 % of patients per year.

Living, autologous pulmonary artery conduits tissue engineered from human umbilical cord cells

BACKGROUND

Tissue engineering represents a promising approach to in vitro creation of living, autologous replacements with the potential to grow, repair, and remodel. Particularly in a congenital operation, there is a substantial need for such implantation materials. We previously demonstrated fabrication of completely autologous, functional heart valves on the basis of peripheral vascular cells. Presently the feasibility of creating pulmonary artery conduits from human umbilical cord cells was investigated.

METHODS

Human umbilical cord cells were harvested and expanded in culture. Pulmonary conduits fabricated from rapidly bioabsorbable polymers were seeded with human umbilical cord cells and grown in vitro in a pulse duplicator bioreactor. Morphologic characterization of the generated neo-tissues included histology, transmission, and scanning electron microscopy. Characterization of extracellular matrix was comprised of immunohistochemistry. Extracellular matrix protein content and cell proliferation were quantified by biochemical assays. Biomechanical testing was performed using stress-strain and burst-stress tests.

RESULTS

Histology of the conduits revealed viable, layered tissue and extracellular matrix formation with glycosaminoglycans and collagens I and III. Cells stained positive for vimentin and alpha-smooth muscle actin. Scanning electron microscopy showed confluent, homogenous tissue surfaces. Transmission electron microscopy demonstrated elements typical of viable myofibroblasts, such as collagen, fibrils, and elastin. Extracellular matrix proteins were significantly lower compared with native tissue; the cell content was increased. The mechanical strength of the pulsed constructs was comparable with native tissue; the static controls were significantly weaker.

CONCLUSIONS

In vitro fabrication of tissue-engineered human pulmonary conduits was feasible utilizing human umbilical cord cells and a biomimetic culture environment. Morphologic and mechanical features approximated human pulmonary artery. Human umbilical cord cells demonstrated excellent growth properties representing a new, readily available cell source for tissue engineering without necessitating the sacrifice of intact vascular donor structures.

Hemoglobin concentration in multiple versus singleton pregnancies--retrospective evidence for physiology not pathology

OBJECTIVE

To describe hemoglobin (Hb) levels and percentiles for multiple pregnancies and to compare them with reference ranges of singleton pregnancies as published by the Center for Disease Control.

STUDY DESIGN

Maternal hemoglobin and red cell indices were compared: (a) between multiple and singleton pregnancies of our hospital and (b) with trimester-specific cut-offs for singleton pregnancies obtained from literature.

RESULTS

While early pregnancy hemoglobin values were similar in multiple and singleton pregnancies, second trimester values decreased much faster in multiple pregnancies. Nadir in multiple pregnancies was reached in weeks 24-28 of gestation. In the third trimester mean hemoglobin values were higher in multiple pregnancies, while 5th and 10th percentile were still lower compared to singleton pregnancies at term. The mean whole-pregnancy hemoglobin exceeded the Center for Disease Control (CDC) cut-off for anemia in singleton pregnancies (fifth percentile) and red cell indices remained constant.

CONCLUSION

We conclude that with a significantly lower fifth percentile than introduced by the CDC in all trimesters, there should be different cut-offs for anemia in multiple pregnancies considered. A more pronounced decrease in multiple pregnancy hemoglobin levels seems to be physiological.

[Current aspects of diagnosis and therapy of iron deficiency anemia in pregnancy]

Anaemia is one of the most common risk factors in the area of obstetrics and perinatal medicine. During pregnancy and in the puerperium it is associated with an increased incidence of both maternal and fetal morbidity and mortality, the extent of which is dependent upon the severity of anaemia and the resulting complications. In order to correctly diagnose the type and degree of anaemia, a prerequisite for selection of the proper therapy, one must first of all correctly differentiate between the relative, i.e., the physiological anaemia of pregnancy due to the normal plasma volume increase during pregnancy, and "real anaemias" with various different pathophysiological causes. When defining the Hb cutoff value for anaemia in pregnancy, the extent of the plasma volume changes with respect to the gestational age must be taken into consideration. It has been found that haemoglobin values < 11.0 g/dl in the first and third trimesters, and < 10.5 g/dl in the second trimester may point to an anaemic situation which should be further clarified. The first important steps for diagnosing anaemia in a pregnant patient include a thorough check of her medical history and a medical examination. This procedure often lays the basis for a correct diagnosis. The current gold standard to detect iron deficiency remains the serum ferritin value. To be reliable, this requires the ruling out of an infection (chronic or acute) as a cause of the anaemia. We recommend a complete laboratory test for the exact haematological status as well as the assessment of specific chemical laboratory parameters. These should include a palette of additional, promising new parameters such as hypochromic red cells and transferrin receptors which allow more accurate detection of iron deficiency and differential diagnosis of iron deficiency anaemia. After correct diagnosis, major emphasis should be put on safe and effective treatment of anaemia which again depends on severity of anaemia, time for restoration and patients characteristics. Today effective alternatives to oral iron only or blood transfusion such as parenteral iron sucrose complex and in selected cases also recombinant erythropoietin have been investigated and show promising results concerning effective treatment of anaemia during pregnancy and postpartum.

[Two-stage delivery after spontaneous rupture of fetal membranes and delayed abortion of the first twin in conservative management]

INTRODUCTION

1-2% of all twin pregnancies are complicated by premature contractions, leading to premature rupture of membranes before 26 weeks of pregnancy. In this situation, a decision is required to either actively induce premature delivery or to initiate expectant management. Maternal and fetal risks regarding perinatal mortality and morbidity and the benefits of pregnancy prolongation have to be weighted against each other.

CASE REPORT

We present delayed deliveries of two I-Parae with dichorionic twin pregnancies, achieved by in vitro fertilisation. In both cases, spontaneous membrane rupture and miscarriage of the leading fetus occurred prior to 20 gestational weeks. As signs of infection were missing initially, we adopted a conservative, expectant management. In both cases, the pregnancies could be prolonged to more than 30 weeks' gestation.

DISCUSSION

In the absence of additional risk factors, expectant, conservative management of multiple pregnancies after loss of one fetus can lead to pregnancy prolongation of 91 and 96 days, respectively. The gained gestational age of the remaining fetus and the healthy mother-child pairs are discussed under perinatal, economical and psychological aspects.

Efficacy and safety of intravenously administered iron sucrose with and without adjuvant recombinant human erythropoietin for the treatment of resistant iron-deficiency anemia during pregnancy

OBJECTIVE

This study was undertaken to determine the efficacy and safety of intravenously administered iron sucrose with versus without adjuvant recombinant human erythropoietin in the treatment of gestational iron-deficiency anemia resistant to therapy with orally administered iron alone.

STUDY DESIGN

Forty patients with gestational iron-deficiency anemia were randomly assigned to receive intravenously iron sucrose plus recombinant human erythropoietin or iron sucrose alone twice weekly. Target hemoglobin value was 11.0 g/dL. Efficacy measures were reticulocyte count, increase in hematocrit, and time to target hemoglobin level (treatment duration in weeks and need for continued therapy after 4 weeks).

RESULTS

Both regimens were effective, but with adjuvant recombinant human erythropoietin the reticulocyte counts were higher from day 4 (P<.01), increases in hematocrit were greater from day 11 (P <.01), and the median duration of therapy was shorter (18 vs 25 days), with more patients reaching the target hemoglobin level by 4 weeks of treatment (n = 19 vs. n = 15). The groups did not differ with respect to maternal-fetal safety parameters.

CONCLUSION

Adjuvant recombinant human erythropoietin safely enhanced the efficacy of iron sucrose in the treatment of gestational iron-deficiency anemia resistant to orally administered iron alone.

Intravenous versus oral iron supplementation for preoperative stimulation of hemoglobin synthesis using recombinant human erythropoietin

To compare two modalities of iron supplementation for the preoperative stimulation of erythropoiesis using recombinant human erythropoietin (rhEPO), 12 adults in normal hemoglobin and iron status due for elective surgery were randomized to rhEPO 200 U/kg body weight subcutaneously twice weekly combined with either iron sucrose 200 mg intravenously twice weekly or iron sulfate 160 mg/day orally, for 3 weeks preoperatively. Efficacy was measured by the increases over baseline in hemoglobin, reticulocyte count, and ferritin determined 3 days before surgery; preoperative reticulocyte count and ferritin were significantly higher with intravenous iron, whereas the only significant intragroup increases in hemoglobin between time points also occurred in this group. Intravenous iron significantly boosts the hematopoietic response to rhEPO and prevents iatrogenic iron depletion in otherwise healthy candidates for elective surgery.

Intraoperative endogenous erythropoietin levels and changes in intravascular blood volume in healthy humans

There is accumulating evidence of a relationship between changes in intravascular blood volume and endogenous erythropoietin (EPO) levels. In this study, eight healthy adult American Society of Anesthesiologists class-I patients due for prolonged elective surgery were randomised either to preoperative hypervolaemic haemodilution using hydroxyethyl starch, followed by intraoperative crystalloid infusion, or to standard intraoperative normovolaemic fluid balance management using crystalloids (control group). Electrolytes, creatinine, urea, osmolality, urine output and blood gases were monitored pre- and intraoperatively for 6 h, Comparable cardiopulmonary and renal homeostasis were maintained in both groups. We found that central venous pressure increased and EPO levels decreased, both significantly, in the hypervolaemic haemodilution group relative to controls. There were no significant intergroup changes in any other parameters. By controlling for other known determinants of EPO levels, our data indicate a relationship between EPO levels and changes in intravascular blood volume in humans, supporting the notion of EPO as a volume-regulated, and possibly volume-regulating, hormone.

Erythropoietin test methods

Recombinant human erythropoietin (rhEPO), which increases red cell mass, is one of the most abused substances in sport. Abuse is currently undetectable by the only direct routine method, immunoassay, since blood and urine rhEPO are immunologically indistinguishable from endogenous EPO. Elevated EPO levels are only detectable several days after rhEPO administration. Indirect parameters have therefore been introduced, primarily the haematocrit level, but also markers of functional iron deficiency during or after rhEPO administration (hypochromic red cells and reticulocytes, serum transferrin receptors, ferritin levels) and, in the urine, fibrin degradation products. Although iron status indices have yielded promising results, athletes are currently banned solely on the basis of their haematocrit. Yet various factors can cause false positive haematocrit results with potentially fatal consequences to athletes' careers. Until new direct assays such as liquid chromatography-mass spectrometry have been evaluated and introduced, efforts must be directed at using a battery of tests to increase the sensitivity and specificity and reduce the number of false positives and false negatives.

Effectiveness of recombinant erythropoietin and iron sucrose vs. iron therapy only, in patients with postpartum anaemia and blunted erythropoiesis

BACKGROUND

To compare efficacy between recombinant human erythropoietin (rhEPO) plus parenteral iron vs. iron alone (parenteral vs. oral) in postpartum anaemia.

METHODS

Sixty patients (haemoglobin 8.6 +/- 1.1 g dL-1) were randomized to rhEPO plus intravenous (i.v.) iron sucrose (group 1), rhEPO placebo plus i.v. iron sucrose (group 2), or oral iron alone (group 3), daily for 4 days beginning 48-72 h postpartum. Erythropoiesis and iron status were assessed before, and on 4, 7 and 14 days after, starting therapy.

RESULTS

On day 7 the group 1 haematocrit increase was 7.7 +/- 3.1% vs. 5.3 +/- 1.9% (group 2, P < 0.01) and 4.4 +/- 3.2% (group 3, P < 0.01), and on day 14, 11.3 +/- 2.9% vs. 9.2 +/- 3.4% (group 2, P < 0.05) and 8 +/- 2.8% (group 3, P < 0.01). The odds of achieving a target haematocrit > 32% on day 7 and > 35% on day 14 were higher on rhEPO (1.5-2.7) than on either iron regimen alone. Group 1 reticulocyte counts were also higher on days 4 (P < 0.05 vs. oral iron) and 7 (P < 0.01 vs. oral and parenteral iron).

CONCLUSION

All three regimens were effective in postpartum anaemia, but the haematocrit and reticulocyte responses to rhEPO plus parenteral iron were significantly greater than to iron alone. Benefit was greatest in the blunted erythropoiesis subgroup with elevated post-Caesarean section C-reactive protein levels.

Unexplained elevated serum hCG is associated with raised amniotic fluid erythropoietin levels in second-trimester pregnancies

OBJECTIVE

This study was designed to investigate the association between the concentrations of maternal serum hCG and amniotic fluid erythropoietin during the second trimester of pregnancy.

METHODS

In a prospective case-control study, 42 consecutive singleton pregnancies showing unexplained elevated serum hCG concentrations (>2.0 multiples of the median, MoM) in Down's syndrome screening and 27 control pregnant women undergoing midtrimester amniocentesis because of a previous cytogenetic abnormality were studied.

RESULTS

The mean amniotic fluid erythropoietin concentration in the study group was 1.8 (range 0.61-8.7) MoM, whereas it was 1.1 (range 0.71-3. 96) MoM in the controls (p = 0.035). A significantly increasing relationship (p < 0.05) was found between the concentrations of maternal serum hCG and amniotic fluid erythropoietin.

CONCLUSIONS

The results of the current study revealed in vivo the association between elevated hCG and amniotic fluid erythropoietin levels which, in turn, supports the concept of early placental damage. The underlying pathology seems to be sufficient to cause an erythroblastic response.

Induction of fetal hemoglobin synthesis with recombinant human erythropoietin in anemic patients with heterozygous beta-thalassemia during pregnancy

OBJECTIVE

Recombinant human erythropoietin (rhEPO) increases fetal hemoglobin synthesis in nonpregnant thalassaemic patients. We used rhEPO in 4 pregnant patients with heterozygous beta-thalassemia and anemia to study its effect on erythropoiesis, F cell production, and HbF synthesis.

METHODS

Patients were treated with a combination therapy of rhEPO and iron. The effect on HbF synthesis was assessed by the percentage of F reticulocytes, F cells, and total HbF, erythropietis by reticulocyte count, and hemoglobin measurements and iron status by ferritin levels, transferrin saturation, and percentage of hypochromic red cells.

RESULTS

RhEPO caused an increase of F reticulocytes (1.5 to 10.5 fold), F cells (5.0 to 7.7 fold), and HbF (1.4 to 2.2 fold). All patients showed an increase of young, immature reticulocytes and had elevated reticulocytes at the end of therapy. Hemoglobin increased with a range from 0.3 to 1.5 g/dL. Transferrin saturation and ferritin levels were normal at the end of the study. There was an increase of the percentage of hypochromic red cells, indicating functional iron deficiency after rhEPO administration despite supplemental iron.

CONCLUSIONS

RhEPO stimulates both HbF synthesis and erythropoiesis in pregnant patients with heterozygous beta-thalassemia and anemia. Since it is known that high HbF levels ameliorate thalassemia symptoms in nonpregnant patients, use of rhEPO for the treatment of severe anemia in thalassaemic patients during pregnancy might be further evaluated.

[Effect of continuous intravenous tocolysis with beta 2-mimetics and magnesium sulfate on erythropoietin level]

14 pregnant women receiving continuous intravenous tocolysis for threatened miscarriage were studied for an effect of beta 2-mimetics on erythropoiesis in humans. After tocolytic therapy for 48 h, the hematokrit fell by 14%; conversely erythropoietin levels rose by 88.7%. Increased erythropoiesis was reflected in increased reticulocyte (and reticulocyte subpopulation) counts. There was a significant correlation between cumulative tocolytic dose and erythropoietin elevation at 48 h. The hypervolemia evidenced by the decreased hematocrit was due to the increased oral fluid intake and fluid retention, and was the presumed main cause of the elevated erythropoietin levels. This effect could enhance understanding of the control of erythropoietin secretion. A similar mechanism may account for the increase in erythropoietin levels in pregnancy.

[Parenteral iron therapy: problems and possible solutions]

To investigate whether there are differences in the frequency of ADRs (adverse drug reactions) to parenteral iron preparations, we compared the results of 4 different data collections which contain observations in particular on i.m. or i.v. iron dextran and i.v. iron hydroxide sucrose complex, primarily in relation to anaphylactic/anaphylactoid reactions and common exanthemas. 1. In 206 patients of the department of general internal medicine in a city/teaching hospital (in association with the Swiss Foundation for Comprehensive Hospital Drug Monitoring--CHDM), 4 probably allergic reactions to i.m. iron dextran were found, one with acute severe dyspnea, cyanosis and flush, 3 with slight generalized, probably allergic reactions. Data from the USA on i.v. iron dextran do not show marked differences in the frequency of ADRs as compared with our data with i.m. administration. 2. A group of 400 otherwise healthy patients of the obstetric department of Zurich University Hospital were treated with i.v. iron sucrose for anemia due to iron loss during pregnancy or following childbirth. Seven generalized skin reactions, 4 in the form of flush and 3 of common exanthema, occurred. 3. In a retrospective study on patients on maintenance hemodialysis with chronic renal insufficiency and anemia, a questionnaire was answered by the medical heads of 17 selected hemodialysis units in Switzerland. Response was 100%. During around 8100 patient-years with approximately 160,000 ampoules of iron sucrose (with 100 mg elementary iron), not a single life threatening reaction was observed; only 5-7 situations of rapidly reversible blood pressure fall occurred, some 10 with flush, and one each with urticaria and vomiting/diarrhea. 4. The relatively good tolerance of i.v. iron sucrose in patients with chronic renal failure may be due either to reduced immune competence in patients with chronic renal insufficiency and/or to the use of the preparation itself, or probably both. 5. In ADRs of allergic appearance to iron sucrose, the 7 generalized skin reactions occurred on the first day of the injections, as did those under iron dextran. Preexisting hypersensitivity must be taken into consideration. 6. If our experience is confirmed, preventive measures with i.v. iron sucrose, mainly in patients with chronic renal insufficiency, could be reduced.

Use of recombinant human erythropoietin in combination with parenteral iron in the treatment of postpartum anaemia

The authors compared the effect of recombinant human erythropoietin (rhEPO) in combination with iron with that of iron therapy only in the treatment of postpartum anaemia. Ninety patients (30 patients/group) received either rhEPO (300 U kg-1, i.v. or s.c., once) and iron (parenteral and oral), or iron therapy only. Erythropoiesis was assessed by haemoglobin and haematocrit increase, absolute reticulocyte counting and reticulocyte flow cytometry. Ferrokinetics was assessed by serum ferritin, transferrin and transferrin saturation measurements. There was no difference before therapy for baseline haematological values or iron status. Patients with endogenous EPO levels below 145 mU mL-1 had a significant benefit from intravenous rhEPO administration with highest haematocrit and haemoglobin levels 4 and 14 days after therapy. rhEPO-treated groups showed a higher absolute reticulocyte count 1 and 4 days after therapy and an elevated percentage of high fluorescent reticulocytes (HFRs). Parenteral iron therapy caused a significant increase of ferritin and transferrin saturation, while transferrin concentration decreased. Ferritin and transferrin levels were lowest after i.v. administration of rhEPO, 1 and 4 days after therapy. C-reactive protein concentration was highest in patients who underwent caesarean section until the end of the observation period. A single dose of rhEPO in combination with iron was more effective in treating postpartum anaemia than iron therapy only, in patients who had low EPO levels despite peripartal blood loss. Postpartum low endogenous EPO levels might be a consequence of inhibiting inflammatory cytokines that are released after spontaneous or operative deliveries.

Optimal timing of repeated rh-erythropoietin administration improves its effectiveness in stimulating erythropoiesis in healthy volunteers

We studied the effect of recombinant human erythropoietin (rhEPO) on erythropoiesis when given at different time intervals to healthy adults. 15 volunteers were randomly selected to receive rhEPO (2 x 300 U/kg) and parenteral iron (2 x 200mg) either within a 24 h or 72 h interval. Controls received parenteral iron only. Maximum EPO levels were found 24 h after the first intravenous injection (day 1) with a mean value of 364 and 390 U/l for the rhEPO-treated groups. When second rhEPO administration was after 72 h (group III), volunteers showed significantly higher absolute reticulocyte counts and a higher percentage of young RNA-rich reticulocytes (HFR ratio) over several days compared to those who received rhEPO within a 24 h interval (group II). Both rhEPO-treated groups showed an increase in the mean reticulocyte cell volume. Reticulocyte haemoglobin concentration was inversely correlated with the increasing cell size with a nadir on day 8. Reticulocyte haemoglobin content showed a significant decrease in group II after day 5. Serum ferritin levels showed an inverse pattern to the rate of erythropoiesis. After an initial rise, the serum ferritin decrease was most pronounced in group III. Contrary to previous reports with oral iron supplementation, functional iron deficiency was not seen during rhEPO stimulation, due to parenteral iron administration. Our data suggest that the time has interval between repeated administrations of rhEPO has an important influence on its pharmacodynamics. rhEPO given within an interval of 72 h was more effective in stimulating erythropoiesis than administration within 24 h interval for the same total dose.

Recombinant human erythropoietin and parenteral iron in the treatment of pregnancy anemia: a pilot study

Our aim was to correct severe iron deficiency anemia during pregnancy by using a combination therapy of recombinant human erythropoietin and parenteral iron. Eleven anemic pregnant women were treated once weekly until a hemoglobin value of 11.0 g/dl was reached. Red blood cell production was monitored by reticulocyte flow cytometry and hemoglobin increase. Iron status was assessed by serum ferritin values and transferrin saturation values. 8/11 patients showed an immediate response, noted by a continuous increase of reticulocytes, high fluorescent reticulocyte ratio and hemoglobin levels. Three patients who had lower serum ferritin values, low transferrin saturation and a lower reticulocyte count before treatment showed little response. The combination of rhEPO and parenteral iron is effective in stimulating erythropoiesis and in treating certain pregnancy anemias. This therapy could be an alternative for patients refusing blood transfusions or who are resistant to iron alone. Poor response to the treatment can be due to insufficient iron supplementation during therapy with rhEPO or due to factors that inhibit erythropoiesis during pregnancy, such as undetected infections.

rhEPO treatment of postpartum anemia

Postpartum hemorrhage is a continuing problem occurring in 5-10% of all deliveries. Due to recent problems with blood transfusion, heterologous blood is nowadays restricted to life-threatening indications. As a consequence the clinician is faced with many patients suffering from overt symptoms of anemia. We therefore investigated the effect of recombinant human erythropoietin (rhEPO) in combination with adequate iron supplementation as an alternative for blood transfusion in postpartum anemia. In a pilot study we could show that rhEPO can enhance the effect of endogenous erythropoietin on erythropoiesis. These data could be confirmed in a larger randomized trial. In another study we could show that rhEPO given s.c. is as effective as i.v. Measurement of the iron stores, however, demonstrated low values at the end of pregnancy indicating that iron is a limiting factor for erythropoiesis in postpartum anemia. In a next study i.v. iron combined with rhEPO showed a greater increase in Hb compared to i.v. iron alone. The chosen dose of i.v. iron, however, was too small as shown by the low ferritin levels. We concluded from these previous studies that rhEPO enhances endogenous erythropoiesis, but so far the effect was only slight (ca 1 g/dl within 14 days); all treated patients developed overt iron deficiency in terms of low ferritin levels despite oral and i.v. iron supplementation; no major side-effects were seen. A further study in healthy non pregnant volunteers demonstrated an effect on erythropoiesis lasting for 3-4 days after a single dose of 300 U/kg rhEPO.(ABSTRACT TRUNCATED AT 250 WORDS)