Figure 5: Schematic of experimental procedure for formation of
enhanced spheroids using ECM modified oxygenating MPs and two liver cell
lines. B) Quantification of albumin and urea secretion into the media
over the culture period (10 days). Data represented as mean ± SD. n = 3
independent spheroids. Statistics via two-way ANOVA followed by a
Tukey’s post hoc testing.
As Figure 5B shows, the more mature laminin isoforms 511 and
521 boosted albumin and urea production compared to the other groups
(p < 0.01), providing evidence that these two isoforms
can more closely reflect the in vivo composition of cells present
in the liver. Consistent with this interpretation laminin-511 and -521
coated surfaces were proved to improve culture matrices for hepatic
specification and differentiation of human pluripotent stem cells
(hPSCs),[43] as well as human embryonic stem cells
(hESC).[44] We also considered laminin-111 to
represent a variation of laminin not found abundantly in the adult liver
to compare the difference between liver specific isotypes to
non-specific ones. Laminin-111 is expressed during embryogenesis and
plays an important role in assembling early basement
membranes.[45] We did not find any significant
differences (p> 0.05) between laminin-111 conjugated and
non-coated MPs in terms of liver specific functions probed, highlighting
the importance of proteins native to the mature in vivo liver
environment for benefitting cell culture in vitro . Our result is
consistent with an experiment conducted by Klaas et. al[46] where they cultured HepG2 cells on 3D nano-
and microfiber structures based on gelatin, preincubated with
laminin-111 and observed no significant changes in cell morphology,
viability and production of proteins between coated with laminin-111 and
uncoated 3D gelatin scaffolds.