Expandable Sendai-Virus-Reprogrammed Human iPSC-Neuronal Precursors: In Vivo Post-Grafting Safety Characterization in Rats and Adult Pig.

One of the challenges in clinical translation of cell-replacement therapies is the definition of optimal cell generation and storage/recovery protocols which would permit a rapid preparation of cell-treatment products for patient administration. Besides, the availability of injection devices that are simple to use is critical for potential future dissemination of any spinally targeted cell-replacement therapy into general medical practice. Here, we compared the engraftment properties of established human-induced pluripotent stem cells (hiPSCs)-derived neural precursor cell (NPCs) line once cells were harvested fresh from the cell culture or previously frozen and then grafted into striata or spinal cord of the immunodeficient rat. A newly developed human spinal injection device equipped with a spinal cord pulsation-cancelation magnetic needle was also tested for its safety in an adult immunosuppressed pig. Previously frozen NPCs showed similar post-grafting survival and differentiation profile as was seen for freshly harvested cells. Testing of human injection device showed acceptable safety with no detectable surgical procedure or spinal NPCs injection-related side effects.

The future treatment for type 1 diabetes: Pig islet- or stem cell-derived ß cells?

Replacement of ß cells is only a curative approach for type 1 diabetes (T1D) patients to avoid the threat of iatrogenic hypoglycemia. In this pursuit, islet allotransplantation under Edmonton's protocol emerged as a medical miracle to attain hypoglycemia-free insulin independence in T1D. Shortage of allo-islet donors and post-transplantation (post-tx) islet loss are still unmet hurdles for the widespread application of this therapeutic regimen. The long-term survival and effective insulin independence in preclinical studies have strongly suggested pig islets to cure overt hyperglycemia. Importantly, CRISPR-Cas9 technology is pursuing to develop "humanized" pig islets that could overcome the lifelong immunosuppression drug regimen. Lately, induced pluripotent stem cell (iPSC)-derived ß cell approaches are also gaining momentum and may hold promise to yield a significant supply of insulin-producing cells. Theoretically, personalized ß cells derived from a patient's iPSCs is one exciting approach, but ß cell-specific immunity in T1D recipients would still be a challenge. In this context, encapsulation studies on both pig islet as well as iPSC-ß cells were found promising and rendered long-term survival in mice. Oxygen tension and blood vessel growth within the capsules are a few of the hurdles that need to be addressed. In conclusion, challenges associated with both procedures, xenotransplantation (of pig-derived islets) and stem cell transplantation, are required to be cautiously resolved before their clinical application.

Effect of different warm ischemic time on islet isolation and function in pigs / 中华内分泌外科杂志

Objective To study the effect of different warm-ischemia time on islet structure, yield and function. Methods Adult pigs were studied, and according to warm ischemic time (WIT, 0, 10, 20, 30, 45 min), the porcine pancreata were divided into 5 groups (A, B, C, D, and E group). The isolation of adult porcine pancreas was carried out by injection of Hanks into pancreatic duct and digestion with collagenase Ⅴ and Ⅰ. A discontinuous Ficoll 400 solution was applied for purifying islets. The structure, purity and viability of islets were determined by dithizone staining and AO/PI staining, and the function of islets was evaluated by the glucose stimulating insulin release test. Results There were little islets debris in group A, B and C. But it was very difficult to obtain integrate islets in group E. There was no significant difference between the groups of 0, 10 and 20 min in islet number before and after islet purification ( P ＞ 0.05 ), while the difference was significant when warm ischemic time was prolonged to 30 min and 45 min ( P ＜ 0. 01 ). In respect of islet function, the similar results were found in different groups. Conclusions When WIT is within 20 min, there is no deleterious effects on islet morphology and yield as well as function. However, when WIT is prolonged to 30 min, the loss in islet yield is severe, and the islet function is significantly impacted.