Ta. Davis et al., EFFECT OF SPACEFLIGHT ON HUMAN STEM-CELL HEMATOPOIESIS - SUPPRESSION OF ERYTHROPOIESIS AND MYELOPOIESIS, Journal of leukocyte biology, 60(1), 1996, pp. 69-76
Humans subjected to periods of microgravity develop anemia, thrombocyt
openia, and abnormalities in red blood cell structure, The causes of t
hese abnormalities are complex and unclear, The in vitro effects of sp
aceflight on hematopoietic cell proliferation and differentiation were
investigated during the space shuttle missions STS-63 (Discovery) and
STS-69 (Endeavour). CD34(+) bone marrow progenitor cells were culture
d in liquid suspension culture and on hematopoietic supportive stromal
cells using hollow-fiber culture modules, One set of cultures was mai
ntained at microgravity (flight cultures) for the last 8-10 days of cu
lture and a second control was at full gravity (ground control), Over
the 11- to 13-test-day period, ground control culture total cell numbe
r increased 41.0- to 65.5-fold but flight culture total cell number in
creased only 10.1- to 11.6-fold (51-84% decrease), Comparing ground co
ntrol cultures and microgravity cultures, respectively, for progenitor
cell content, myeloid progenitor cell numbers expanded 2.6- to 17.5-f
old compared with 0.9- to 7.0-fold and erythroid progenitor cell numbe
rs expanded 2.0- to 4.1-fold in ground control cultures but actually d
eclined at microgravity (> 83% reduction), Moreover, microgravity cult
ures demonstrated accelerated maturation/differentiation toward the ma
crophage lineage, These data indicate that spaceflight has a direct ef
fect on hematopoietic progenitor cell proliferation and differentiatio
n and that specific aspects of in vitro hematopoiesis, particularly er
ythropoiesis, involve gravity-sensitive components.