I. Constantinidis et A. Sambanis, TOWARDS THE DEVELOPMENT OF ARTIFICIAL ENDOCRINE TISSUES - P-31 NMR SPECTROSCOPIC STUDIES OF IMMUNOISOLATED, INSULIN-SECRETING ATT-20 CELLS, Biotechnology and bioengineering, 47(4), 1995, pp. 431-443
Transformed, insulin-secreting endocrine cells have been proposed as a
n alternative to islets for the development of a bioartificial pancrea
s. With appropriate immunoprotection, such cells may be implanted with
out the need for patient immunosuppression. Use of continuous cell lin
es alleviates the cell availability limitation, but poses questions re
garding the stability and biochemical and secretory function of the pr
eparation, especially in the longterm. We have developed a bioreactor/
perfusion perfusion system, compatible with a horizontal-bore NMR inst
rument, that can maintain immunoprotected endocrine cells for prolonge
d periods of time. P-31 NMR spectroscopy was used to study the bioener
getics of recombinant, insulin-secreting mouse pituitary AtT-20 cells
entrapped as spheroids in calcium alginate/poly-L-lysine/alginate bead
s. NMR provided data verifying the macroscopic homogeneity within the
bioreactor and allowing the evaluation of changes in cellular bioenerg
etics for a period of 70 days under different culture conditions. Leve
ls of high-energy phosphates changed slightly during the first 40 days
of the experiment, then decreased considerably as cell death occurred
. Rates of glucose consumption and insulin-related peptide secretion a
lso remained constant for 40 days and decreased rapidly thereafter. Th
is study constitutes the beginning of an extensive quantitative analys
is of the biochemistry of transformed endocrine cell lines in a seques
tered, artificial tissue environment. (C) 1995 John Wiley and Sons, In
c.