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Background:
The relationship
between fibroblasts,
myofi broblasts, and
smooth muscle cells
within the airway
wall remains poorly
understood.
Objective:
The cellular
characteristics of
primary bronchial
fibroblasts from
patients with asthma
were investigated by
evaluating the
expression of 3
proteins: αsmooth
muscle actin (SMA),
fibronectin
containing extra
type III domain A (EDAcFN),
and smoothelin.
Methods: Expression
of SMA, EDAcFN, and
smoothelin was
evaluated in primary
fibroblasts from 3
patients with asthma
of varying symptom
severity, embryonic
fibroblasts, and a
healthy control. In
addition, primary
bronchial
fibroblasts from
patients with asthma
were assessed for
SMA at various
incubation times (4
hours to 76 hours)
and with different
extracellular
matrices (ECMs).
Immunofluorescence
was assessed by
manually counting
cells that stained
positively as fine f
lamentous structures
under a fluorescence
microscope.
Results:
Expression of
filamentous SMA
tended to increase
with the length of
incubation. The
positive to total
cell ratio for
filamentous cells
did not differ
significantly
between the various
kinds of ECMs onto
which cells were
plated (P>.05).
Primary bronchial
fibroblasts from
asthma patients
produced more
prominent expression
of EDAcFN than
control fibroblasts.
Smoothelin was not
expressed in any
fibroblasts.
Conclusions:
More than 50% of
primary bronchial
fibroblasts were
defined as
myofibroblasts.
Primary bronchial
fibroblasts in
patients with asthma
had more potential
for tissue fibrosis
than control
fibroblasts. No
mature smooth muscle
cells were observed
in primary bronchial
fibroblasts in
patients with
asthma.
Key words:
Asthma. Fibroblast.
Smooth muscle actin.
Fibronectins.
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