Nonoxidative ethanol metabolites alter extracellular matrix protein content in rat pancreas.
OBJECTIVE
The mechanisms involved in ethanol-induced pancreas fibrosis are poorly understood. Here we show that fatty acid ethyl esters (FAEEs), nonoxidative ethanol metabolites, increase extracellular matrix (ECM) protein levels in pancreas.


METHODS
Rat pancreatic acini were incubated for 1-4 hours with FAEEs or acetaldehyde. In another set of experiments, rats received an intravenous infusion of FAEEs for 6 hours. Collagens were assessed by a hydroxyproline assay. Laminin and fibronectin were analyzed by Western blotting. Gene expression of ECM proteins was measured by conventional and real-time reverse-transcription polymerase chain reaction (RT-PCR). Matrix metalloproteinase (MMP), plasmin, and urokinase-type plasminogen activator (uPA) activities were determined by zymography and fluorogenic assays.


RESULTS
FAEEs increased collagen, laminin, and fibronectin levels in pancreatic acini without affecting messenger RNA (mRNA) expression for these proteins. Actinomycin D, a transcriptional inhibitor, did not block the increase in ECM proteins induced by FAEEs. FAEEs reduced the activity of the serine protease, plasmin, and that of the uPA. Consistent with these results, the serine protease inhibitor aprotinin reproduced the effects of FAEEs and prevented the further increase in ECM proteins induced by FAEEs. In vivo administration of FAEEs reduced plasmin and uPA activities and increased ECM protein levels in pancreas. Acetaldehyde had minor effects on ECM protein levels and did not affect plasmin activity.


CONCLUSIONS
FAEEs increase ECM protein levels in pancreas. The results suggest that this effect is caused primarily by an inhibition in ECM degradation via serine proteases including the plasminogen system.
Lugea
Aurelia
A
University of Southern California-University of California Research Center for Alcoholic Liver and Pancreatic Diseases, Veterans Affairs Greater Los Angeles Healthcare System, 90073, USA. alugea@ucla.edu
Gukovsky
Ilya
I
Gukovskaya
Anna S
AS
Pandol
Stephen J
SJ
D000079:Acetaldehyde / Q000633:toxicity; D000818:Animals; D002478:Cells, Cultured; D003094:Collagen / Q000032:analysis; D000431:Ethanol / Q000378:metabolism*; D016326:Extracellular Matrix Proteins; D005227:Fatty Acids / Q000633:toxicity*; D005341:Fibrinolysin / Q000032:analysis; D005353:Fibronectins / Q000032:analysis; D005355:Fibrosis; D007797:Laminin / Q000032:analysis; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D010179:Pancreas / Q000737:chemistry / Q000187:drug effects* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism
D016326:Extracellular Matrix Proteins; D005227:Fatty Acids; D005353:Fibronectins; D007797:Laminin; D000431:Ethanol; D003094:Collagen; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; D000079:Acetaldehyde