Yield, cell composition, and function of islets isolated from different ages of neonatal pigs

Double transgenic neonatal porcine islets as an alternative source for beta cell replacement therapy

To be clinically efficient, beta cell replacement therapies such as pig islet xenotransplantation must ensure sufficient insulin secretion from grafted islets. While protection from host immune reaction is essential for islet engraftment and their subsequent functioning, intrinsic physiological properties of used cells are also a key factor. We have previously shown that islets with adenoviral-mediated expression of a dipeptidyl peptidase-resistant form of glucagon-like-peptide-1 (GLP-1) and a constitutively activated form of type 3 muscarinic receptor (M3R) in their beta cells have greatly improved insulin secretory response to glucose stimulation that is otherwise 4 to 10 times lower than human islets. Here, we describe in vitro characterization of the secretory function of pancreatic islets, derived from transgenic pigs expressing the GLP-1M3R cassette under the porcine insulin promoter (InsGLP-1M3R), and their usage to treat insulin-dependent diabetes in an immunodeficient mouse model. Our results show that InsGLP-1M3R islets isolated from neonatal and adult pigs secrete up to 15-fold more insulin in response to glucose stimulation compared to wild-type (WT) islets. They also proved to be more efficient in treating diabetes in a preclinical model as shown by a significantly higher percentage of normoglycemic recipients and higher porcine C-peptide levels up to 9 mo post implantation.

Ethical and legislative advances in xenotransplantation for clinical translation: focusing on cardiac, kidney and islet cell xenotransplantation

In this state-of-the-art review we detail the journey of xenotransplantation from its infancy, detailing one of the first published cases and the subsequent journey the field took in its inception and development. With a focus on the science, technological advances, precautions required along with the potential limitations in application, the ethics, guidance's, and legislative advances that are required to reach the safe and efficacious clinical application of xenotransplantation. Along with a view over the past several decades with the overall significant advancements in pre-clinical study outcomes particularly in islet, kidney, and heart xenotransplantation, to ultimately reach the pinnacle of successful clinical heart and kidney xenotransplants. It outlines the importance for the appropriate guidance's required to have been developed by experts, scientists, clinicians, and other players who helped develop the field over the past decades. It also touches upon patient advocacy along with perspectives and expectations of patients, along with public opinion and media influence on the understanding and perception of xenotransplantation. It discusses the legislative environment in different jurisdictions which are reviewed in line with current clinical practices. All of which are ultimately based upon the guidance's developed from a strong long-term collaboration between the International Xenotransplantation Association, the World Health Organisation and The Transplantation Society; each having constantly undertaken consultation and outreach to help develop best practice for clinical xenotransplantation application. These clearly helped forge the legislative frameworks required along with harmonization and standardization of regulations which are detailed here. Also, in relation to the significant advances in the context of initial xeno-kidney trials and the even greater potential for clinical xeno-islet trials to commence we discuss the significant advantages of xenotransplantation and the ultimate benefit to our patients.