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

The expression of Galalpha-(1,3)Gal (alphaGal) on porcine islet cells remains controversial. Several groups have reported that porcine islet endocrine cells do not express alphaGal while we have shown in neonatal porcine islets (NPI) that beta cells do express this antigen. We hypothesize that endocrine cells expressing alphaGal 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 beta cells. Thus, we further examined alphaGal 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 alphaGal 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 beta cells. Moreover, a significantly higher proportion of CK7-positive cells was detected in the Gal-expressing population compared with non-expressing cells. In contrast, a higher proportion of beta cells was observed in the Gal-negative population compared with the Gal-positive population. These data showed a reduced expression of alphaGal and CK7 as porcine islet cells mature into beta cells suggesting a possible role for alphaGal in the maturation of pancreatic endocrine beta cells.