Absence of toxicity associated with adenoviral-mediated transfer of the beta-galactosidase reporter gene to neonatal rat islets in vitro

Transfer of genes with potential therapeutic utility to the pancreatic isle ts of Langerhans may enhance graft survival after islet transplantation. Th e aim of this study was to determine the optimal conditions for adenoviral- mediated gene transfer to the islets of Langerhans in the absence of vector -induced toxicity. Neonatal rat islets were transduced in groups of 25 with an adenoviral vector encoding beta-galactosidase (Ad beta Gal) at doses of MOI 0, 10, 100 and 1000 pfu per islet cell. All experiments were performed in triplicate. Efficiency of gene transfer was determined by gross inspect ion and estimation of the percentage of beta-galactosidase positive cells a fter islet dispersion at 1, 4, 7 and 10 days post-transduction. Islet toxic ity was assessed by measuring accumulated insulin levels at each time-point and by assessing static incubation insulin release at 3 and 10 days. Effic ient dose-dependent gene transfer to the islets was documented at 1, 4, 7 a nd 10 days post-transduction. Transgene expression was relatively stable fo r the duration of the experiment. Insulin accumulation did not differ betwe en transduced and non-transduced islets at each timepoint. Likewise, the in sulin secretory response to glucose, obtained by dividing the insulin respo nse to high glucose incubation by the insulin response to low glucose incub ation was similar in transduced and non-transduced islets at 3 and 10 days at all doses studied. In summary, adenoviral-mediated transduction of islet s results in dose dependent efficient gene transfer with relatively stable transgene expression in the absence of toxicity. This technology may be use ful in the study of islet biology and also in the future in gene therapy ap proaches to the treatment of diabetes mellitus. (C) 1999 Elsevier Science I reland Ltd. All rights reserved.