Rl. Gallo et al., ENDOTHELIAL-CELL SURFACE ALKALINE-PHOSPHATASE ACTIVITY IS INDUCED BY IL-6 RELEASED DURING WOUND REPAIR, Journal of investigative dermatology, 109(4), 1997, pp. 597-603
Phosphatase activity on endothelial cell surfaces is responsible, in p
art, for the conversion of adenosine nucleotides to adenosine, a poten
t vasodilator and anti-inflammatory mediator that can protect tissues
from the ischemic damage that results from injury. To evaluate whether
phosphatases are actively induced by a soluble factor released follow
ing injury, the effect of tissue fluids collected from porcine or huma
n skin wounds was tested on primary cultures of endothelial cells. Pho
sphatase activity increased approximate to 50-fold following 48-h cult
ure in the presence of wound fluid. Inductive activity was present onl
y in fluids collected during the inflammatory phase of wound repair. T
he phosphatase activity metabolized adenosine monophosphate to free ph
osphate and was the liver/bone/kidney alkaline phosphatase isoenzyme:
activity was temperature- and levamisole-sensitive, 1-phenylalanine-re
sistant, and linked to the cell surface via phospholipid, and migrated
at a size identical to this isozyme. interleukin-6 was identified as
the phosphatase-inducing factor in wound fluid and the related cytokin
es, leukaemia inhibiting factor and oncostatin M, caused a similar deg
ree of alkaline phosphatase induction. Therefore, following injury, ac
cumulation of interleukin-6 can lead to production by alkaline phospha
tase of adenosine and subsequent protection from ischemic injury.