In vitro and in vivo expression of Galα-(1,3)Gal on porcine islet cells is age dependent

The expression of Ga1α-(1,3)Ga1 (αGa1) on porcine islet cells remains controversial. Several groups have reported that porcine islet endocrine cells do not express αGa1 while we have shown in neonatal porcine islets (NPI) that β cells do express this antigen. We hypothesize that endocrine cells expressing αGa1 on NPI are less mature cells that may have originated from ductal cells and that expression of this antigen disappears as they develop into fully mature β cells. Thus, we further examined αGa1 expression on various porcine islet cell preparations and correlated this with the proportion of cytokeratin 7 (CK7)-positive ductal cells. In vitro and in vivo expression of a1 and CK7 was significantly (P<0.05) higher in less mature NPI cells compared with matured NPI and adult porcine islet cells while the reverse was observed in the proportion of β cells. Moreover, a significantly higher proportion of CK7-positive cells was detected in the Ga1-expressing population compared with non-expressing cells. In contrast, a higher proportion of β cells was observed in the Ga1-negative population compared with the Ga1-positive population. These data showed a reduced expression of αGa1 and CK7 as porcine islet cells mature into β cells suggesting a possible role for αGa1 in the maturation of pancreatic endocrine β cells.