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Medizin - Open Access LMU - Teil 09/22 Podcast
Time-dependent appearance of myofibroblasts in granulation tissue of human skin wounds

Time-dependent appearance of myofibroblasts in granulation tissue of human skin wounds

Medizin - Open Access LMU - Teil 09/22 vor 34 Jahren

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Human skin wounds (66) inflicted between 20 h and 7 months prior to
biopsy were studied. In order to identify the type of cellular
differentiation of the fibroblastic cells in the granulation
tissue, alpha-smooth muscle actin and desmin were
immunohistochemically localized. The value of any presumed
time-dependent appearance and/or disappearance of positively
stained cells was tested for the estimation of wound age. In skin
specimens with a wound age less than 5 days (n =15) no typical
granulation tissue had developed and no alpha-actin-positive
myofibroblasts could be detected. The first appearance of
positively reacting myofibroblasts was noted in a 5-day-old wound.
In 57% of the lesions with a wound age between 5 and 31 days (25
out of 44 cases) typical granulation tissue formation was present
and myofibroblasts with positive reaction for alpha-smooth muscle
actin could be identified. Numerous positively reacting cells could
generally be found in wounds aged between 16 and 31 days, but also
in wounds less than 16 days old. In 29% of the cases with a wound
age of more than 31 days (2 out of 7 cases) alpha-sma-positive
myofibroblasts also occured. Fibroblastic cells positive for desmin
could not be seen at all in our series. Our results demonstrate the
appearance of alpha-sma-positive myofibroblasts with the initial
formation of typical granulation tissue in human skin lesions as
early as approximately 5 days after wounding. In contrast to recent
experimental results these cells remained detectable in wounds aged
more than 2 months in some cases. The immunohistochemical detection
of actin-positive cells, therefore, demonstrates whether an unknown
skin wound is aged approximately 5 days or more. Even though a
time-dependent decrease of myofibroblasts in human granulation
tissue after 31 days in human wounds seems probable, the extended
presence (up to about 2 months) of these cells allows no further
exact age determination of older wounds.