ASGSB 2003 Annual Meeting Abstracts
THE HEMATOPOIETIC STEM
CELL THERAPY FOR MUSCLE LOSS DURING EXPLORATION OF SPACE.
S. Ramsahai1, B.C. Kim1, A.N. Roach1, D.
University & Hospital, Washington D.C., and
College of Wisconsin, Milwaukee, W.I.
The prolonged exposure to space environments results in severe/invasive
disorders in astronauts such as muscle and bone losses. Hematopoietic stem
cells exhibit extraordinary plasticity because they can differentiate to all
types of blood cells, as well as transdifferentiate into various tissues such
as muscle and bone. We have hypothesized that the hematopoietic stem cell
therapy (HSCT) could alleviate space-caused muscle loss so as to maintain
astronautsí homeostasis in space. To investigate HSCT for muscle loss, donor
HSCs were genetically marked either by transfecting with
or by preparing from
transgenic mouse (LacZ mouse) and cultured in a liquid suspension culture
system. When the marked HSCs were stained by X-gal, 60% of the transfected
HSCs stained blue and 100% of the LacZ-HSCs stained blue. The LacZ-HSCs were
transplanted to a hindlimb suspended mouse (strain 129S) and differentiation
of HSCs to muscles were investigated by X-gal staining procedure. Although the
HSCs were injected to thigh and gastrocnemius muscles of the right leg only,
both right and left legs were stained bluish. The weight of combined legs was
14% heavier than that of the control suspended mouse. Histochemical analysis
indicated the structural contribution of HSCs to muscle. We are now analyzing
transitions of myosin heavy chain isoforms in unloaded muscles during hindlimb
suspension using SDS-PAGE system. This experiment will lead to determining the
interval and frequency of HSCT during the hindlimb unloading. In the future,
HSCT for muscle loss may be applied to long-term bed-rest patients.
(Supported by NIAC/USRA grants)
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