C. Sundberg et al., MICROVASCULAR PERICYTES EXPRESS PLATELET-DERIVED GROWTH-FACTOR-BETA RECEPTORS IN HUMAN HEALING WOUNDS AND COLORECTAL ADENOCARCINOMA, The American journal of pathology, 143(5), 1993, pp. 1377-1388
The expression of platelet-derived growth factor-beta (PDGF-beta) rece
ptors in the microvasculature of human healing wounds and colorectal a
denocarcinoma was investigated. Frozen sections were subjected to doub
le immunofluorescence staining using monoclonal antibodies (MAbs) spec
ific for pericytes (MAb 225.28 recognizing the high-molecular weight-m
elanoma-associated antigen, expressed by activated pericytes during an
giogenesis), endothelial cells (MAb PAL-E), laminin, as well as PDGF-b
eta receptors (MAb PDGFR-B2) and its ligand PDGF-B chain (MAb PDGF 007
). Stained sections were analyzed by computer-aided imaging processing
that allowed for a numerical quantification of the degree of colocali
zation of the investigated antigens. An apparent background colocaliza
tion, varying between 23 and 35%, between markers for cells not expect
ed to co-localize was recorded This background could be due to limitat
ions of camera resolution, to out-of-focus fluorescence, and to interd
igitations of the investigated structures. In all six tumor specimens,
co-localization of PDGF-beta receptors and PAL-E was not different fr
om the background co-localization, whereas that of PDGF-beta receptors
and high-molecular weight-melanoma-associated antigen was significant
ly higher with mean values between 57 and 71%. Qualitatively, the same
pattern was obtained in the two investigated healing wounds. PDGF-B c
hain did not co-localize with either PAL-E or high-molecular weight-me
lanoma-associated antigen, but PDGF-B chain-expressing cells were, how
ever, frequently found juxtaposed to the microvasculature. The express
ion of PDGF-beta receptors on pericytes in activated microvessels and
the presence of PDGF-B chain-expressing cells in close proximity to th
e microvasculature of healing wounds and colorectal adenocarcinoma is
compatible with a role of PDGF in the physiology of the microvasculatu
re in these conditions.