Blood, Vol. 94 No. 1 (July 1), 1999:
pp. 97-105
Expression of the Thrombopoietin Gene in Human Fetal and Neonatal
Tissues
Eva-Maria Wolber,
Christof Dame,
Hubert Fahnenstich,
Dietmar Hofmann,
Peter Bartmann,
Wolfgang Jelkmann, and
Joachim Fandrey
From the Institute of Physiology, Medical University of Luebeck,
Luebeck, Germany; the Department of Neonatology, University of Bonn;
and the Institute of Pediatric Pathology, University of Bonn, Bonn,
Germany.
Thrombopoietin (TPO) regulates megakaryopoiesis and platelet
production. In the adult, TPO is mainly produced by the liver and the
kidneys. This study focuses on fetal and neonatal TPO mRNA expression.
In 26 human fetuses and preterm neonates, samples from liver, kidney,
spleen, lung, and bone marrow were extracted for total RNA. We measured
platelet counts, TPO serum concentrations by enzyme-linked
immunosorbent assay, and TPO mRNA contents by reverse
transcription/competitive polymerase chain reaction. TPO mRNA concentrations per microgram total RNA were similar in liver, spleen, and bone marrow, slightly lower in kidney, and significantly lower in lung. When related to gram tissue, TPO mRNA levels were highest in the liver. Considering the total amount of TPO mRNA produced
in liver, kidney, and spleen, the liver accounted for 95.3%. No
correlations between TPO mRNA expression and serum TPO concentration,
blood platelet count, or gestational age were observed. In conclusion,
the liver is the primary site of TPO gene expression in human fetuses
and neonates. The spleen may contribute to TPO production during fetal
life. Like in the adult, TPO mRNA is expressed in fetal bone marrow.
