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

Abstract

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

Gene Editing, Gene Therapy, and Cell Xenotransplantation: Cell Transplantation Across Species

“…This humoral reaction is even stronger against islets from neonatal pigs since they show higher expression of the αGal epitope compared to adult pigs [20]. A major breakthrough in this field was the knockout of both alleles of the α 1,3-galactosyltransferase enzyme (GGTA1) which synthesizes the αGal epitope resulting in the first transgenic pigs lacking this major xenoantigen [21].…”

Immunological Challenges Facing Translation of Alginate Encapsulated Porcine Islet Xenotransplantation to Human Clinical Trials

“…However, through genetic modifi cations, specifi cally, alpha 1,3-galactosyltransferase gene knockout (GTKO), porcine islets may be modulated to lack expression of this epitope. Nonetheless, non-encapsulated GTKO porcine islets and wild type islets were both rejected subsequent to nonhuman primate transplantation, suggesting alternative antigens are likely involved in rejection of tissue lacking complete enclosure [ 45 ]. Interestingly, a drawback of utilizing adult porcine islets with a dormant Gal epitope was that certain infl ammatory cytokines detrimental to adult beta-cell survival were found to be less hostile to FP ICC and NPCC survival [ 46 ].…”

异种胰岛移植中供体猪的筛选: 现状与进展

“…However, the main problem with ICCs is the need for long-term maturation (2-3 months) to achieve in vivo functionality (Hardikar et al, 2002). A second disadvantage is the relatively high expression of galactose-α-1,3-galactose (Gal) on the surface of ICCs, rendering wild-type (WT) pig ICCs more susceptible to xenorejection than adult pig islets (APIs), which express negligible amounts of Gal epitope (only 5% of total cells) (Bennet et al, 2000;Rayat et al, 2003;Dor et al, 2004;Komoda et al, 2004). In non-diabetic cynomolgus monkeys, pig ICCs transplanted under kidney capsules were almost completely destroyed by immune rejection within 12 d post-transplantation (Sӧderlund et al, 1999).…”

“…Though insulin secretion is also delayed after transplantation in vivo, the maturation time of NPIs (>4 weeks) is significantly shorter than that of ICCs (>2 months) ( Table 1). The origin of xeno-antigenicity of pig NPIs is mainly N-linked sugars including sialic acid and α-Gal antigens (up to 11%-19%) (Rayat et al, 2003;Omori et al, 2006); however, the transplanted NPIs induce a lower T-cell response than APIs in patients with insulin-dependent diabetes mellitus (Bloch et al, 1999). Recently, the growing demonstrations of prolonged diabetes reversal after transplantation of WT NPIs in immunosuppressed primates make neonatal pig an alternative source of islet grafts for future clinical application (Cardona et al, 2006;Elliott et al, 2007;Thompson et al, 2011a;Wang et al, 2011).…”