An increasing demand for cell-based diabetes therapy could be met through xenotransplantation of adult porcine islets. Use of islet xenotranplantation on a large scale would require rigorous safety and quality control measures to maximize transplant success. Development of molecular tools to monitor porcine islet cellular responses to ischemic, osmotic, mechanical and oxidative stresses during islet cell processing and post-isolation culturing would aid the rational design of cytoprotective strategies aimed at improving transplant outcomes. In addition, gene expression signatures informative for islet quality could serve as an adjunct to physiological testing to establish the suitability of islet products for transplantation. Experiment Overall Design: Nine adult Landrace sows were sacrificed, the pancreases were dissected, and islet cells isolated as previously described. Islet preparation purity was assessed by light microscopy after staining with diphenylthiocarbazone and ranged between 90-95% for the preparations used. Profiles of islet cells cultured under standard conditions were compared to islet cells cultured under stress conditions with elevated glucose (16.7 mM) or addition of inflammatory cytokines (IL-1beta, TNF-alpha, and IFN-gamma), or both, for 48 hours.

Identify molecular markers of physiological and immunological stress in porcine islets in anticipation of their use in xenotransplantation.

Porcine islets were cultured under stress conditions of elevated glucose, inflammatory cytokine addition (IL-1beta, TNF-alpha, IFN-gamma), or both for 48 hours and gene expression changes monitored by microarray spotted with the Pig_Array_Ready Oligo set and quantitative RT-PCR.

Changes observed from hyperglycemia included increased thioredoxin interacting protein (TXNIP) and metabolic process mRNAs. Cytokine treatment increased expression of JAK-STAT pathway components, oxidative stress (transglutaminase 2 - TGM2), and beta-cell dysfunction genes. The transcription factor, C/EBPdelta was elevated by cytokine treatment. Apolipoprotein C3 and transthyretin have been identified as markers for type 2 diabetes and were also elevated as was MARCKS, a substrate of PKC and known to change in cells under diabetic conditions.

Thioredoxin interacting protein (TXNIP) and transglutamase 2 (TGM2, not previously identified in rodent or human studies) may be useful molecular markers of islet cell stress (hyperglycemia and cytokine stress, respectively).

• stress and apoptosis in islets/ beta cells: 751, 2000, 2001, 2020, 2021, 2301, 2904, 3244, 3650, 3975, 3977, 3979, 3980,