Platelet-activating factor synthesis and response on pancreatic islet endothelial cells: relevance for islet transplantation.
BACKGROUND
Recent data suggest that donor intraislet endothelial cells may survive islet transplantation and participate to the events that influence islet engraftment. However, the mechanisms that regulate islet endothelial behavior in this setting are poorly known.


METHODS
We obtained immortalized human (hIECs) and mouse (mIECs) islet endothelial cells by transfection with SV40-T-large antigen and studied the synthesis and response to Platelet-activating factor (PAF), a multipotent phospholipid that acts as endothelial mediator of both inflammation and angiogenesis.


RESULTS
HIECs showed typical endothelial markers such as expression of vWF, CD31, and CD105, uptake of acetylated-LDL and binding to ULE-A lectin. Moreover, they expressed nestin, the PAF-receptor and possess surface fenestrations and in vitro angiogenic ability of forming tubular structures on Matrigel. Likewise, mIECs showed expression of vWF, CD31, nestin, PAF-receptor and CD105, and uptake of acetylated-LDL. HIECs and mIECs rapidly produced PAF under stimulation with thrombin in a dose-dependent way. Exogenous PAF or thrombin-induced PAF synthesis increased leukocyte adhesion to hIECS and mIECs and cell motility of both endothelial cell lines. Moreover, PAF or thrombin-induced PAF synthesis accelerated in vitro formation of vessel-like tubular structures when hIECs are seeded on Matrigel. Notably, gene-microarray analysis detected up-regulation of beta3 integrin gene on hIECs stimulated with PAF, that was confirmed at the protein level.


CONCLUSIONS
Based on the novel development of immortalized islet endothelium, these results suggest that PAF may have a dual role that links inflammation to angiogenesis in the early events of islet transplantation.
Department of Internal Medicine and Research Center for Experimental Medicine (CeRMS), University of Torino, Torino, Italy.
Luigi
L
Biancone
Vincenzo
V
Cantaluppi
Giuseppe Mauriello
GM
Romanazzi
Simona
S
Russo
Federico
F
Figliolini
Silvia
S
Beltramo
Elisa
E
Scalabrino
Maria Chiara
MC
Deregibus
Renato
R
Romagnoli
Alessandro
A
Franchello
Mauro
M
Salizzoni
Paolo Cavallo
PC
Perin
Camillo
C
Ricordi
Giuseppe Paolo
GP
Segoloni
Giovanni
G
Camussi
D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000235:genetics; D002460:Cell Line; D002465:Cell Movement; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000502:physiology*; D006801:Humans; D007515:Islets of Langerhans / Q000098:blood supply / Q000502:physiology*; D016381:Islets of Langerhans Transplantation / Q000502:physiology*; D051379:Mice; D020411:Oligonucleotide Array Sequence Analysis; D010972:Platelet Activating Factor / Q000096:biosynthesis* / Q000235:genetics; D014162:Transfection
D000952:Antigens, Polyomavirus Transforming; D010972:Platelet Activating Factor