Beta-cell replacement therapy (pancreas and islet transplantation) for treatment of diabetes mellitus: an integrated approach

International workshop: islet transplantation without borders enabling islet transplantation in Greece with international collaboration and innovative technology

Recently, initiatives have been undertaken to establish an islet transplantation program in Athens, Greece. A major hurdle is the high cost associated with the establishment and maintenance of a clinical-grade islet manufacturing center. A collaboration was established with the University Hospitals of Geneva, Switzerland, to enable remote islet cell manufacturing with an established and validated fully operational team. However, remote islet manufacturing requires shipment of the pancreas from the procurement to the islet manufacturing site (in this case from anywhere in Greece to Geneva) and then shipment of the islets from the manufacturing site to the transplant site (from Geneva to Athens). To address challenges related to cold ischemia time of the pancreas and shipment time of islets, a collaboration was initiated with the University of Arizona, Tucson, USA. An international workshop was held in Athens, December 2011, to mark the start of this collaborative project. Experts in the field presented in three main sessions: (i) islet transplantation: state-of-the-art and the "network approach"; (ii) technical aspects of clinical islet transplantation and outcomes; and (iii) islet manufacturing - from the donated pancreas to the islet product. This manuscript presents a summary of the workshop.

Construction of Plasmid Insulin Gene Vector Containing Metallothionein IIA (pcDNAMTChIns) and Carbohydrate Response Element (ChoRE), and Its Expression in NIH3T3 Cell Line

BACKGROUND

Type 1 diabetes mellitus is one of the metabolic diseases that cause insulin-producing pancreatic ß cells be destroyed by immune system self-reactive T cells. Recent-ly, new treatment methods have been developed including use of the stem cells, ß islet cells transplantation and gene therapy by viral and non-viral gene constructs.

OBJECTIVES

The aim of this project was preparing the non-viral vector containing the glucose inducible insulin gene and using it in the NIH3T3 cell line.

MATERIALS AND METHODS

Cloning was carried out by standard methods. Total RNA was extracted from pancreatic tissue, RNA was converted to cDNA using RT-PCR reaction and preproinsulin gene was amplified using specific primers. PNMTCH plasmid was extract-ed and digested by NotI, HindIII, and MTIIA and ChoRE genes were purified and cloned into pcDNA3.1 (-) plasmid and named pcDNAMTCh. Finally, the preproinsulin genes were cloned into pcDNA3.1 (-) plasmid and pcDNAMTChIns was built.

RESULTS

The cloned gene constructs were evaluated by restriction enzyme digestion and RT-PCR. The NIH3T3 cells were transfected by plasmid naked DNA containing preproinsu-lin gene and expression was confirmed by Reverse Transcriptase PCR and Western Blot-ting Techniques.

CONCLUSIONS

Gel electrophoresis of PCR products confirmed that cloning was per-formed correctly. The expression of preproinsulin gene in recombinant plasmid in NI-H3T3 cell line was observed for the first time. The findings in this study can be the basis of further research on diabetes mellitus type 1 gene therapy on animals.

Asiatic acid preserves beta cell mass and mitigates hyperglycemia in streptozocin-induced diabetic rats

BACKGROUND

Type 1 diabetes is a chronic condition in which the pancreas produces little or no insulin due to the loss or dysfunction of pancreatic beta cells. This study investigated the beneficial effects of asiatic acid-a triterpenoid compound-preserved beta mass and mitigated hyperglycemia in streptozocin-induced diabetic rats.

METHODS

Diabetes mellitus was induced in adult male Wistar rats by a single intraperitoneal injection of streptozocin (60 mg/kg body weight). The diabetic rats were divided into untreated and asiatic acid (25 mg/kg) groups. Controls were intraperitoneal injection with citrate buffer. Blood glucose level, plasma insulin, and pancreas immunohistochemistry analysis were examined after a 2-week experimental period. AKT and Bcl-xL expression in the pancreatic islets of rats were evaluated by Western blot methods.

RESULTS

Blood glucose levels were significantly reduced in rats receiving asiatic acid after streptozocin administration. Asiatic acid concomitantly increased serum insulin levels in diabetic rats. Immunohistochemical staining revealed a marked preservation by asiatic acid of insulin-producing beta cells in the pancreatic islets of the diabetic rats. Furthermore, asiatic acid in vivo induced pro-survival Akt kinase activation and Bcl-xL expression in the pancreatic islets of diabetic rats.

CONCLUSIONS

These results suggest that asiatic acid exerts its glucose-lowering effects, in part through influences on beta-cell mass. Asiatic acid administration resulted in preservation and restoration of beta-cell mass and function in diabetic rodent models.

Do immunotherapy and beta cell replacement play a synergistic role in the treatment of type 1 diabetes?

Type 1 diabetes (T1D) is the result of the autoimmune response against pancreatic insulin-producing ss-cells. Its ultimate consequence is beta-cell insufficiency-mediated dysregulation of blood glucose control. In terms of T1D treatment, immunotherapy addresses the cause of T1D, mainly through re-setting the balance between autoimmunity and regulatory mechanisms. Regulatory T cells play an important role in this immune intervention. An alternative T1D treatment is beta-cell replacement, which can reverse the consequence of the disease by replacing destroyed beta-cells in the diabetic pancreas. The applicable insulin-producing cells can be directly obtained from islet transplantation or generated from other cell sources such as autologous adult stem cells, embryonic stem cells, and induced pluripotent stem cells. In this review, we summarize the recent research progress and analyze the possible advantages and disadvantages of these two therapeutic options especially focusing on the potential synergistic effect on T1D treatment. Exploring the optimal combination of immunotherapy and beta-cell replacement will pave the way to the most effective cure for this devastating disease.

[Pancreatic islets transplantation in the treatment of diabetes mellitus: present and future]

Diabetes treatment with insulin does no prevent the development of secondary complications. For this reason, treatments other than conventional ones are needed, which could bring about an <<almost physiological>> metabolic regulation. This can only be done by transplanting insulin producing tissue, such as vascularised pancreas transplantation, which is an already consolidated clinical procedure these days, or by islets transplantation, which is still a procedure in the clinical research phase. This has the same metabolic objectives as the vascularised transplant, but without the risks of major abdominal surgery, since the islets are implanted in the liver with minimal surgery or using interventionist radiology by means of a catheter. A clinical trial (Edmonton Protocol) was published in the year 2000, which improved the results after islet transplantation by obtaining normoglycaemia periods of more than one year in a consecutive patient series with type 1 diabetes and without using corticoids. This protocol has been endorsed in other centre in different trials. Although the initial results were good, the progress of these patients has shown that many islets transplantations do not manage to maintain insulin-independence indefinitely.

New potential treatments for protection of pancreatic B-cell function in Type 1 diabetes

Type 1 diabetes mellitus results from the progressive and specific autoimmune destruction of insulin-secreting pancreatic B-cells, which develops over a period of years and continues after the initial clinical presentation. The ultimate goal of therapeutic intervention is prevention or reversal of the disease by the arrest of autoimmunity and by preservation/restoration of B-cell mass and function. Recent clinical trials of antigen-specific or non-specific immune therapies have proved that modulation of islet specific autoimmunity in humans and prevention of insulin secretion loss in the short term after the onset of disease is achievable. The identification of suitable candidates for therapy, appropriate dosage and timing, specificity of intervention and the side-effect profile are crucial for the success of any approach. Considering the complexity of the disease, it is likely that a rationally designed approach of combined immune-based therapies that target suppression of B-cell specific autoreactivity and maintenance of immune tolerance, coupled with islet regeneration or replacement of the destroyed B-cell mass, will prove to be most effective in causing remission/reversal of disease in a durable fashion.

The role of total pancreatectomy and islet autotransplantation for chronic pancreatitis

Total pancreatectomy and islet autotransplantation are done for chronic pancreatitis with intractable pain when other treatment measures have failed, allowing insulin secretory capacity to be preserved, minimizing or preventing diabetes, while at the same time removing the root cause of the pain. Since the first case in 1977, several series have been published. Pain relief is obtained in most patients, and insulin independence preserved long term in about a third, with another third having sufficient beta cell function so that the surgical diabetes is mild. Islet autotransplantation has been done with partial or total pancreatectomy for benign and premalignant conditions. Islet autotransplantation should be used more widely to preserve beta cell mass in major pancreatic resections.

Beta-cell replacement in immunosuppressed recipients: old and new clinical indications

Islet transplantation is an appealing procedure able to improve glycemic control in type 1 diabetic patients. However, the possible side effects that may be induced by immunosuppressive therapy limit its application to a select number of patients for whom the risk of immunosuppressants' side effects can be justified. For patients with type 1 diabetes mellitus-who will take immunosuppressants regardless, as they require a solid organ transplant-islet infusion can be an interesting therapeutic option for improving metabolic compensation, whenever pancreas transplant is not possible. Hence, islet infusion can be an important therapeutic option for patients with secondary diabetes mellitus even when a minor pancreatic endocrine function remains. For these patients, results may be better than those obtained with islet infusion for patients with type 1 diabetes mellitus thanks to the lack of autoimmune reaction to the infused islets. The final result is the improvement of the glycemic compensation and most likely also an extension of the graft survival.

A novel technique for heterotopic vascularized pancreas transplantation in mice to assess ischemia reperfusion injury and graft pancreatitis

BACKGROUND

Although various suture techniques for murine pancreas transplantation have been described, severe limitations have limited their widespread use. We therefore designed a surgical model for cervical heterotopic pancreas transplantation using a cuff technique.

METHODS

C57BL6 mice were used as donor and recipient pairs. Recipients were rendered diabetic with streptozotocin and subsequently transplanted. The donor pancreas was isolated using a no-touch technique and then placed in the recipient's cervical region. Vascular anastomoses were completed by pulling the portal vein over the external jugular vein cuff and the donor aortic segment over the carotid cuff and fixed with an 8-0 ligature thereby facilitating a nonsuture technique. To test applicability of this model, graft microcirculation was evaluated by intravital microscopy after prolonged cold ischemia (16 h).

RESULTS

The immediate success rate was >90%. Donor operation lasted 40 +/- 5 min; dissection of recipient vessels lasted 20 +/- 4 min. Revascularization time was 4 to 6 min, resulting in a total pancreas ischemia time of 33 +/- 6 min. No thromboembolic complications on the cuff side were observed. Preoperative glucose levels were 518 +/- 59 mg/dl and returned to normal by postoperative day 1 (88 +/- 13 mg/dl). Histology on postoperative days 10 and 30 showed almost normal islet cell and acinar architecture of all grafts. In groups with prolonged cold ischemia, graft microcirculation was significantly reduced and paralleled by increased inflammation, interstitial edema, hemorrhage, acinar vacuolization, and focal areas of necrosis compared with nonischemic controls.

CONCLUSIONS

This new model may provide an excellent tool to further investigate the pathophysiology as well as novel therapeutic strategies of preservation, ischemia reperfusion injury, and graft pancreatitis.

The role of Islet Neogenesis-Associated Protein (INGAP) in islet neogenesis

Islet Neogenesis-Associated Protein (INGAP) is a member of the Reg family of proteins implicated in various settings of endogenous pancreatic regeneration. The expression of INGAP and other RegIII proteins has also been linked temporally and spatially with the induction of islet neogenesis in animal models of disease and regeneration. Furthermore, administration of a peptide fragment of INGAP (INGAP peptide) has been demonstrated to reverse chemically induced diabetes as well as improve glycemic control and survival in an animal model of type 1 diabetes. Cultured human pancreatic tissue has also been shown to be responsive to INGAP peptide, producing islet-like structures with function, architecture and gene expression matching that of freshly isolated islets. Likewise, studies in normoglycemic animals show evidence of islet neogenesis. Finally, recent clinical studies suggest an effect of INGAP peptide to improve insulin production in type 1 diabetes and glycemic control in type 2 diabetes.

Assessment of islet function following islet and pancreas transplantation

Pancreas and islet transplant recipients are monitored using various metabolic and imaging methods. The inaccessibility of the transplanted whole pancreas and of the isolated islets poses specific problems (eg, all assessment techniques are indirect). Although successful pancreas transplantation typically restores normal glucose homeostasis, islet transplantation into the liver does not completely normalize islet hormone secretion and glucose metabolism. Development of better testing strategies, such as direct islet imaging, will significantly advance the field.

Suitability of human juvenile pancreatic islets for clinical use

AIMS/HYPOTHESIS

The limited availability of deceased donor pancreases suitable for pancreas and islet transplantation calls for a broader utilisation of donor tissue for transplantation purposes. Young donors, representing, fortunately, a minor but significant pool of individuals, have been largely under-employed, mainly because of anatomical and functional incompatibilities with potential recipients. For islet transplantation, the isolation of pancreatic islets from young donors rarely occurs, because of technical problems. As a result of the peculiar characteristics of young donor pancreases, the standard isolation procedure does not allow efficient separation of the islets from the surrounding exocrine tissue, and favours the generation of mantled islets. Nonetheless, young donor islets offer high qualitative and clinically appealing characteristics.

SUBJECTS AND METHODS

We standardised a modified methodology to obtain purified and mantle-free human islets from young donors. This method principally involves efficient delivery of isolation enzyme with reduced mechanical disruption of the pancreas combined with additional filtration steps.

RESULTS

We were able to obtain purified and mantle-free human islets from donors as young as 6 months of age with good morphological and functional properties. The good qualitative characteristics of the islets, evidenced in vitro, were proven in vivo, as they were qualitatively superior to islets of older donors in transplantation studies.

CONCLUSIONS/INTERPRETATION

This study justifies the utilisation of islets derived from young donors for islet transplantation.

Pancreas versus islet transplantation in diabetes mellitus: How to allocate deceased donor pancreata?

Transplant options for the diabetic recipient include pancreas and islet transplantation. Pancreas transplantation has been increasingly performed in the last 3 decades with increasing success rates. Nevertheless, islet transplantation offers the advantage of being less invasive with fewer complications. However, current experience shows that multiple transplants are required to achieve and maintain insulin-independence in the intermediate term, and long-term function remains a problem even with multiple transplants. Early successes with single-donor islet transplants are encouraging and if maintained will largely substitute pancreas transplants. Currently, single-donor islet transplants have been shown to work in recipients with low insulin requirements who receive a pancreas from a donor with high body mass index. However, pancreas transplants from obese donors are associated with increased surgical risk. Therefore, it is logical to preferentially allocate obese donor pancreata to islet recipients. In addition, older donor (50 to 65 years) pancreata could be preferentially allocated to islets since their islet yield is still good, whereas they are associated with decreased survival in whole-organ pancreas transplants. With increasing efficiency and success of islet transplants the criteria for pancreas allocation for islets will need to be periodically reviewed.

[Diabetes Type I therapy through transplantation]

Diabetes is one of the most common chronic diseases in our society. While insulin treatment for diabetes type I could delay and reduce the incidence of diabetic complications, it is associated with an increased risk of severe hypoglycemia. To restore physiologic insulin metabolism, transplantation of insulin producing cells (pancreatic Beta cells) represent the sole available therapy. It could be done either through pancreas or islet of Langerhans transplantation. In this paper, we review actual knowledge regarding these two types of transplantations.

Technique du prélèvement pancréatique pour l'isolement des îlots de Langerhans

AIM OF THE STUDY

The allograft of pancreatic islets represents a potential alternative to insulin therapy in patients suffering from the most severe forms of Type 1 diabetes. Here we report our experience of pancreatic procurement for isolation and islet allograft.

MATERIALS AND METHODS

Pancreata were procured in brain-dead donors. The islets were isolated using techniques developed and validated in pigs and men. Injection of a given preparation was decided after quantitative and qualitative controls. Islets were transplanted in Type 1 diabetic patients already grafted with a kidney or suffering from severe and/or unstable diabetes, after percutaneous or surgical settlement of an intra-portal catheter. Patients received an "Edmonton-like" immunosuppressive protocol. Grafts were repeated once or twice until a total quantity of 10,000 transplanted islet-equivalents was obtained.

RESULTS

Twenty-nine pancreata were procured and 14 preparations were grafted to 7 patients. Eleven graftings were done percutaneously and three were surgical. The initial function of the 14 transplants was confirmed by secretion of C-peptide and decrease of insulin doses. Insulin therapy was completely interrupted in the 5 patients having received at least two grafts.

CONCLUSION

These preliminary clinical results confirmed that the isolation technique of human islets and the technique of pancreas procurement are mastered by our team. If the results of this assay (assessment one year after graft) confirm our hopes, we will be able to offer islet allografts to an increasing number of patients with severe Type 1 diabetes.

Five-year follow-up after clinical islet transplantation

Islet transplantation can restore endogenous beta-cell function to subjects with type 1 diabetes. Sixty-five patients received an islet transplant in Edmonton as of 1 November 2004. Their mean age was 42.9 +/- 1.2 years, their mean duration of diabetes was 27.1 +/- 1.3 years, and 57% were women. The main indication was problematic hypoglycemia. Forty-four patients completed the islet transplant as defined by insulin independence, and three further patients received >16,000 islet equivalents (IE)/kg but remained on insulin and are deemed complete. Those who became insulin independent received a total of 799,912 +/- 30,220 IE (11,910 +/- 469 IE/kg). Five subjects became insulin independent after one transplant. Fifty-two patients had two transplants, and 11 subjects had three transplants. In the completed patients, 5-year follow-up reveals that the majority ( approximately 80%) have C-peptide present post-islet transplant, but only a minority ( approximately 10%) maintain insulin independence. The median duration of insulin independence was 15 months (interquartile range 6.2-25.5). The HbA(1c) (A1C) level was well controlled in those off insulin (6.4% [6.1-6.7]) and in those back on insulin but C-peptide positive (6.7% [5.9-7.5]) and higher in those who lost all graft function (9.0% [6.7-9.3]) (P < 0.05). Those who resumed insulin therapy did not appear more insulin resistant compared with those off insulin and required half their pretransplant daily dose of insulin but had a lower increment of C-peptide to a standard meal challenge (0.44 +/- 0.06 vs. 0.76 +/- 0.06 nmol/l, P < 0.001). The Hypoglycemic score and lability index both improved significantly posttransplant. In the 128 procedures performed, bleeding occurred in 15 and branch portal vein thrombosis in 5 subjects. Complications of immunosuppressive therapy included mouth ulcers, diarrhea, anemia, and ovarian cysts. Of the 47 completed patients, 4 required retinal laser photocoagulation or vitrectomy and 5 patients with microalbuminuria developed macroproteinuria. The need for multiple antihypertensive medications increased from 6% pretransplant to 42% posttransplant, while the use of statin therapy increased from 23 to 83% posttransplant. There was no change in the neurothesiometer scores pre- versus posttransplant. In conclusion, islet transplantation can relieve glucose instability and problems with hypoglycemia. C-peptide secretion was maintained in the majority of subjects for up to 5 years, although most reverted to using some insulin. The results, though promising, still point to the need for further progress in the availability of transplantable islets, improving islet engraftment, preserving islet function, and reducing toxic immunosuppression.

Beta-score: an assessment of beta-cell function after islet transplantation

OBJECTIVE

Success after islet transplantation can be defined in terms of insulin independence, C-peptide secretion, or glycemic control. These measures are interdependent and all need to be considered in evaluating beta-cell function after islet transplantation. For the current study, a composite beta-score was developed that provides an integrated measure of beta-cell function success after islet transplantation.

RESEARCH DESIGN AND METHODS

The proposed scoring system gave 2 points each for normal fasting glucose, HbA(1c), stimulated C-peptide, and absence of insulin or oral hypoglycemic agent use. No points were awarded if the fasting glucose was in the diabetic range, the HbA(1c) was >6.9%, C-peptide secretion was absent on stimulation, or daily insulin use was in excess of 0.24 units/kg. One point was given for intermediate values. The score ranged from 0 to 8 and was correlated with the glucose value 90 min after a standard mixed meal challenge (n = 218) in 57 subjects before and after islet transplantation. The score was also used to follow subjects for up to 5 years after islet transplantation.

RESULTS

The beta-score correlated well with the plasma glucose level 90 min after a mixed meal challenge (r = -0.849, P < 0.001). On follow-up, the beta-score rose after the first transplant and was maintained up to 5 years, demonstrating continuing function of the transplanted beta-cells.

CONCLUSIONS

The beta-score provides a simple clinical scoring system that encompasses glycemic control, diabetes therapy, and endogenous insulin secretion that correlates well with physiological measures of beta-cell function. On this basis, it is suitable as an overall measure of beta-cell transplant function. The beta-score gives an integrated measure of beta-cell function as a continuum that may be more useful than simply assessing the presence or absence of insulin independence.

Pancreas and islet cell transplantation

Transplantation of the pancreas or islet cells constitutes surgical treatment for patients with type 1 diabetes mellitus. Pancreas transplantation is now an established procedure for the surgical treatment of diabetes mellitus. Islet cell transplantation has the potential to be the procedure of choice once it becomes more routine because of the minimal surgery involved. Included in this chapter are the pathophysiology of diabetes, rationale for transplantation, and the surgical procedure itself.