Erythropoiesis is Distinct at Each Stage of Ontogeny

Abstract

ABSTRACT. In vitro erythropoiesis from fetuses, newborn infants, and adults was compared in methyl cellulose cultures. Fetal and newborn blood erythroid colony formation tended to be more sensitive to erythropoietin than adult. The day of maximal colony formation was earlier in fetal than in newborn or adult cultures. The number of colonies/100 000 mononuclear cells on d 13 of culture and on the day of peak growth was highest in fetal, intermediate in newborn, and lowest in adult cultures. Burst forming units-erythroid/mL of blood on culture d 13 and the day of peak growth were similar in fetuses and newborns, and both were significantly greater than in adults. The proportional synthesis of y-globin in fetal colonies was 2-fold greater than in newborn colonies, and 6-fold greater than in adult colonies. Thus, fetal, newborn, and adult erythroid progenitor cultures are each unique with regard to erythropoietin sensitivity, growth time course, number of erythroid colonies, and the proportion of y-globin synthesis. (Pediatr Res 31: 170-175, 1992) Abbreviations BFU-E, burst forming unit-erythroid CFU-E, colony forming unit-erythroid Ep, recombinant human erythropoietin Ep % max, concentration of erythropoietin at which halfmaximal growth was achieved Ep plateau, concentration of erythropoietin beyond which no additional growth was observed MNC, mononuclear cells

A New Methodology of Fetal Stem Cell Isolation, Purification, and Expansion: Preliminary Results for Noninvasive Prenatal Diagnosis

“…The results with several different techniques have already been reported (7)(8)(9)(11)(12)(13)(14). The first report was from Lo et al (9), who cultured in vitro fetal hematopoietic precursors present in the isolated mononuclear cell fraction of peripheral maternal blood.…”

Prenatal Diagnosis of Genetic Abnormalities Using Fetal CD34+Stem Cells in Maternal Circulation and Evidence They Do Not Affect Diagnosis in Later Pregnancies

“…Stem cells are characterized by the expression of the CD34 + cell-surface antigen [37][38][39]. Some studies have demonstrated the fetal blood presents a higher frequency of hematopoietic progenitors than adult peripheral blood [39].…”

“…Further studies will focus on maternal cell suppression and selective "in vitro" culture of fetal cells. Investigations into the best culture time for fetal CD34 + cell growth [29,38], supplements for culture media [41,42], and biological differences between fetal and maternal cells appear to be the most promising approaches [18,43].…”

Soluble factor(s) produced by adult bone marrow stroma inhibit in vitro proliferation and differentiation of fetal liver BFU-E by inducing apoptosis.

“…These include in vivo differentiation almost exclusively along the erythroid pathway (see p. 51 in ref. 30), rapid cycling rate and accelerated in-vitro maturation time (31), greater sensitivity to erythropoietin (31)(32)(33), and decreased sensitivity to GM-CSF (34). In vivo, FL hematopoiesis is almost entirely restricted to the erythroid lineage.…”