Improvement of collagenase distribution with the ductal preservation for human islet isolation

Revisiting pancreatic islet isolation in murine models: A practical and effective technical protocol

The endocrine pancreas is composed of clusters of cell groups called pancreatic islets. These cells are responsible for the synthesis and secretion of hormones crucial for glycemic homeostasis, such as insulin and glucagon. Therefore, these cells were the targets of many studies. One method to study and/or understand endocrine pancreatic physiology is the isolation of these islets and stimulation of hormone production using different concentrations of glucose, agonists, and/or antagonists of specific secretagogues and mimicking the stimulation of hormonal synthesis and secretion. Many researchers studied pancreatic physiology in murine models due to their ease of maintenance and rapid development. However, the isolation of pancreatic islets involves meticulous processes that may vary between rodent species. The present study describes a simple and effective technical protocol for isolating intact islets from mice and rats for use as a practical guide for researchers. The method involves digestion of the acinar parenchyma by intraductal collagenase. Isolated islets are suitable for in vitro endocrine secretion analyses, microscopy techniques, and biochemical analyses.

Quality of life after total pancreatectomy with islet autotransplantation for chronic pancreatitis in Japan

BACKGROUND

Patients with chronic pancreatitis (CP) often have severe and intractable abdominal pain, leading to decreased quality of life (QOL), inability to work or attend school, and increased health care costs due to repeated emergency room visits and hospitalizations.

METHODS

We evaluated the efficacy of total pancreatectomy and islet autotransplantation (TPIAT) in terms of pain control and QOL in CP patients treated at our center in Japan. To evaluate QOL, we used the Short-Form 36 Health Survey version 2 (SF-36v2® Standard, Japanese), European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30), and Quality of Life Questionnaire-Pancreatic Modification (QLQ-PAN28).

RESULTS

Between August 2016 and June 2019, we performed this procedure in 5 patients. All patients were followed up for 12 months and all transplanted islets were still functioning at the 1-year follow-up. The major adverse events were abdominal wall hemorrhage, intestinal obstruction, intra-abdominal abscess, and abdominal pain requiring hospitalization; no case had sequelae. No major complications were due to islet transplantation. Pain scores improved postoperatively in all patients. Three QOL item dimensions role-physical (p = 0.03125), general health perception (p = 0.03125) and vitality (p = 0.03125) in the SF-36 were significantly improved 12 months after TPIAT. Mean values of many other QOL items improved, though not significantly.

CONCLUSION

The QOL improvement after TPIAT for CP suggests its effectiveness in the Japanese population.

Mesenchymal Stem Cells Secretions Enhanced ATP Generation on Isolated Islets during Transplantation

The success of islet transplantation in both basic research and clinical settings has proven that cell therapy has the potential to cure diabetes. Islets intended for transplantation are inevitably subjected to damage from a number of sources, including ischemic injury during removal and delivery of the donor pancreas, enzymatic digestion during islet isolation, and reperfusion injury after transplantation in the recipient. Here, we found that protein factors secreted by porcine adipose-tissue mesenchymal stem cells (AT-MSCs) were capable of activating preserved porcine islets. A conditioned medium was prepared from the supernatant obtained by culturing porcine AT-MSCs for 2 days in serum-free medium. Islets were preserved at 4°C in University of Wisconsin solution during transportation and then incubated at 37°C in RPMI-1620 medium with fractions of various molecular weights prepared from the conditioned medium. After treatment with certain fractions of the AT-MSC secretions, the intracellular ATP levels of the activated islets had increased to over 160% of their initial values after 4 days of incubation. Our novel system may be able to restore the condition of isolated islets after transportation or preservation and may help to improve the long-term outcome of islet transplantation.Abbreviations: AT-MSC, adipose-tissue mesenchymal stem cell; Cas-3, caspase-3; DAPI, 4,6-diamidino-2-phenylindole; DTZ, dithizone; ES cell, embryonic stem cell; FITC, fluorescein isothiocyanate; IEQ, islet equivalent; INS, insulin; iPS cell, induced pluripotent stem cell; Luc-Tg rat, luciferase-transgenic rat; PCNA, proliferating cell nuclear antigen; PDX1, pancreatic and duodenal homeobox protein-1; UW, University of Wisconsin; ZO1, zona occludens 1.

A Practical Guide to Rodent Islet Isolation and Assessment Revisited

Insufficient insulin secretion is a key component of both type 1 and type 2 diabetes. Since insulin is released by the islets of Langerhans, obtaining viable and functional islets is critical for research and transplantation. The effective and efficient isolation of these small islands of endocrine cells from the sea of exocrine tissue that is the rest of the pancreas is not necessarily simple or quick. Choosing and administering the digestive enzyme, separation of the islets from acinar tissue, and culture of islets are all things that must be considered. The purpose of this review is to provide a history of the development of islet isolation procedures and to serve as a practical guide to rodent islet research for newcomers to islet biology. We discuss key elements of mouse islet isolation including choosing collagenase, the digestion process, purification of islets using a density gradient, and islet culture conditions. In addition, this paper reviews techniques for assessing islet viability and function such as visual assessment, glucose-stimulated insulin secretion and intracellular calcium measurements. A detailed protocol is provided that describes a common method our laboratory uses to obtain viable and functional mouse islets for in vitro study. This review thus provides a strong foundation for successful procurement and purification of high-quality mouse islets for research purposes.

Use of hyperglycemic clamp to assess pancreatectomy and islet cell autotransplant in patient with heterotaxy syndrome and dorsal pancreas agenesis leading to chronic pancreatitis

Patients with heterotaxy syndrome (HS) can present with an associated complete dorsal pancreas agenesis (DPA). They are considered to be at increased risk for developing diabetes due to a reduced functional beta cell mass (FBM) as well as for chronic pancreatitis leading to unmanageable pain. We report the case of a young woman with chronic pancreatitis due to HS and associated DPA. She presented with a severe persisting upper abdominal pain refractory to nonsurgical treatment. Unlike in previously reported cases, she had a high FBM (ie, 150% of normoglycemic controls) as determined by hyperglycemic clamp. She underwent a total pancreatectomy followed within 24 hours by an intraportal autologous islet cell transplant containing 4 × 10⁶ beta cells (4700 islet equivalent)/kg body weight. After surgery, the pain resolved, eliminating the need for analgesics. The intraportal implant established an adequate FBM (72% of controls at posttransplant month 2), achieving glycemic control without need for insulin administration. A hyperglycemic clamp can assess the utility and efficacy of an intraportal islet cell autotransplant following total pancreatectomy in patients with HS and complete DPA.

[Current state of the problem of allotransplantation of Langerhans cells (achievements and prospects)]

Literature data devoted to transplantation of Langerhans cells have been analyzed. The main stages, indications, dissection of islets, immunosuppressive therapy, complications and data of the latest clinical trials were discussed.

Total Pancreatectomy with Autologous Islet Cell Transplantation

First described in the early 1980s, total pancreatectomy with autologous islet cell transplantation for the treatment of chronic pancreatitis is still only offered in select centers worldwide. Indications, process details including surgery as well as islet isolation, and results are reviewed. In addition, areas for further research to optimize results are identified.

Pancreatic Islets: Methods for Isolation and Purification of Juvenile and Adult Pig Islets

The current situation of organ transplantation is mainly determined by the disbalance between the number of available organs and the number of patients on the waiting list. This obvious dilemma might be solved by the transplantation of porcine organs into human patients. The metabolic similarities which exist between both species made pancreatic islets of Langerhans to that donor tissue which will be most likely transplanted in human recipients. Nevertheless, the successful isolation of significant yields of viable porcine islets is extremely difficult and requires extensive experiences in the field. This review is focussing on the technical challenges, pitfalls and particularities that are associated with the isolation of islets from juvenile and adult pigs considering donor variables that can affect porcine islet isolation outcome.

Islet product characteristics and factors related to successful human islet transplantation from the Collaborative Islet Transplant Registry (CITR) 1999-2010

The Collaborative Islet Transplant Registry (CITR) collects data on clinical islet isolations and transplants. This retrospective report analyzed 1017 islet isolation procedures performed for 537 recipients of allogeneic clinical islet transplantation in 1999-2010. This study describes changes in donor and islet isolation variables by era and factors associated with quantity and quality of final islet products. Donor body weight and BMI increased significantly over the period (p<0.001). Islet yield measures have improved with time including islet equivalent (IEQ)/particle ratio and IEQs infused. The average dose of islets infused significantly increased in the era of 2007-2010 when compared to 1999-2002 (445.4±156.8 vs. 421.3±155.4×0(3) IEQ; p<0.05). Islet purity and total number of β cells significantly improved over the study period (p<0.01 and <0.05, respectively). Otherwise, the quality of clinical islets has remained consistently very high through this period, and differs substantially from nonclinical islets. In multivariate analysis of all recipient, donor and islet factors, and medical management factors, the only islet product characteristic that correlated with clinical outcomes was total IEQs infused. This analysis shows improvements in both quantity and some quality criteria of clinical islets produced over 1999-2010, and these parallel improvements in clinical outcomes over the same period.

Pancreatic ductal perfusion at organ procurement enhances islet yield in human islet isolation

OBJECTIVE

Pancreas preservation is a major factor influencing the results of islet cell transplantation. This study evaluated the effects of 2 different solutions for pancreatic ductal perfusion (PDP) at organ procurement.

METHODS

Eighteen human pancreases were assigned to 3 groups: non-PDP (control), PDP with ET-Kyoto solution, and PDP with cold storage/purification stock solution. Pancreatic islets were isolated according to the modified Ricordi method.

RESULTS

No significant differences in donor characteristics, including cold ischemia time, were observed between the 3 groups. All islet isolations in the PDP groups had more than 400,000 islet equivalence in total islet yield after purification, a significant increase when compared with the control (P = 0.04 and P < 0.01). The islet quality assessments, including an in vivo diabetic nude mice assay and the response of high-mobility group box protein 1 to cytokine stimulation, also showed no significant differences. The proportion of terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive cells showing apoptosis in islets in the PDP groups was significantly lower than in the control group (P < 0.05).

CONCLUSIONS

Both ET-Kyoto solution and cold storage/purification stock solution are suitable for PDP and consistently resulted in isolation success. Further studies with a larger number of pancreas donors should be done to compare the effects of the PDP solutions.

DCD for Islet Transplantation

Pancreatic islet transplantation has the potential to become the most physiologically advantageous and minimally invasive procedure for the treatment of type 1 diabetes mellitus. Since the first clinical islet transplantation was performed at the University of Minnesota in 1974 [1], the results have been far from ideal for more than two decades in spite of an improvement of islet isolation technique by Ricordi et al. [2–4]. The introduction of the Edmonton protocol, with a highly improved rate of insulin independency, encouraged us to promote clinical islet transplantation [5, 6]. In Japan, we organized the Working Group (The Japanese Islet Transplant Registry) in 1997 under the Japanese Society for Pancreas and Islet Transplantation for the purpose of starting clinical islet transplantation. The first issue of the Working Group was to construct a system of clinical islet transplantation in Japan including the registration of the recipients, procurement of the pancreas for islet isolation and transplantation of the isolated islets. In Japan, afterwards, various problems facing to a start of clinical islet transplantation have been discussed and we completed the guideline for clinical islet transplantation in Japan. The Japanese Organ Transplant Law was enforced in 1997 and organ transplantations using brain dead (DBD) donors were finally started. Since the islet transplantation was not included in the Japanese Organ Transplant Law because it was categorized as tissue transplantation, we were able to use the pancreas only from DCD donors for islet transplantation. The first islet isolation from the human pancreas was performed in 2003.9 and the first islet transplantation was performed in 2004.4 [7–9]. Sixty-five islet isolations and 34 islet transplantations were performed in our country from 2003.9.12 to 2007.3.11 [10].

In this chapter, we describe the current status of clinical islet transplantation using DCD donors in Japan.