1. Improved secretory function of pancreatic islets from InsGLP1M3R piglets
- Author
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Perota, A, Mourad, Nizar, Lagutina, I, Duchi, R, Lazzari, G, Galli, C, Gianello, Pierre, 15th Congress of the International Xenotransplantation Association (IXA 2019), UCL - SSS/IREC/CHEX - Pôle de chirgurgie expérimentale et transplantation, and UCL - (SLuc) Service de chirurgie et transplantation abdominale
- Subjects
endocrine system - Abstract
Background & aims: Clinical pig islet transplantation for the treatment of type I diabetes is still hindered by obvious immunological considerations and less investigated physiological incompatibilities. Cellular encapsulation, donor genetic engineering and host immunomodulation can help improve islet survival in a xenotransplantation context but adequate insulin output from transplanted islets remains the ultimate goal to be achieved for islet transplantation to be clinically efficient. We have previously shown that adenovirus-driven expression of a cassette carrying a dipeptidyl peptidase-resistant form of glucagon-like-peptide-1 (GLP1) and a constitutively activated form of type 3 muscarinic receptor (M3R) in isolated neonatal and adult pig islets significantly increases their secretory response to in vitro glucose stimulation that is otherwise 4-10 times lower than human islets. Our aim in the current study was to replicate our previous results in a transgenic pig model with beta-cell specific expression of our GLP1M3R cassette, to characterize in vivo and in vitro islet function of these pigs and to verify whether their offspring exhibit the same improved insulin secretion as founder animals. Material & methods: Cloned transgenic pigs were produced using Talens technology and validated by TLA sequencing analyses. Pancreata were collected from 14-day old piglets. Insulin secretion in response to different stimuli was evaluated during dynamic islet perifusion experiments. After reaching adult age, selected animals were subjected to IVGTT to study in vivo islet function. Transgenic animals were then bred and islet function of their offspring was studied as for founder animals. Results: Transgenic cloned pig founders (male and female) expressing the GLP1M3R cassette at the beta cell level were successfully obtained. Islets isolated from these piglets showed a 5.5 to 7.5-fold increase of their insulin output upon stimulation with 15 mM glucose. They maintained regulated insulin secretion as basal unstimulated secretion was not significantly increased: stimulation indices of 3.7 to 7.5 compared to 2.6 for control wild type islets. In vivo islet function during IVGTT was evaluated in two animals that both showed a 2 to 3-fold increase of insulin secretion compared to controls. Finally, we examined secretory function of islets isolated from piglets born from transgenic cloned parents. In vitro perifusion experiments showed increased stimulated insulin secretion from transgenic piglets compared to their wild type siblings. Conclusion & perspectives: We obtained the first lines of genetically modified pigs exhibiting enhanced function of their pancreatic islets. Specific expression of modified GLP1 and activated M3R at the beta-cell level enhanced insulin secretion both in vivo and in vitro without affecting viability or fertility and was transmitted to the descendants of cloned animals while maintaining its positive effect on beta-cell function.
- Published
- 2019