Advances in pancreas transplantation

Advances in Innate Immunity to Overcome Immune Rejection during Xenotransplantation

Transplantation is an effective approach for treating end-stage organ failure. There has been a long-standing interest in xenotransplantation as a means of increasing the number of available organs. In the past decade, there has been tremendous progress in xenotransplantation accelerated by the development of rapid gene-editing tools and immunosuppressive therapy. Recently, the heart and kidney from pigs were transplanted into the recipients, which suggests that xenotransplantation has entered a new era. The genetic discrepancy and molecular incompatibility between pigs and primates results in barriers to xenotransplantation. An increasing body of evidence suggests that innate immune responses play an important role in all aspects of the xenogeneic rejection. Simultaneously, the role of important cellular components like macrophages, natural killer (NK) cells, and neutrophils, suggests that the innate immune response in the xenogeneic rejection should not be underestimated. Here, we summarize the current knowledge about the innate immune system in xenotransplantation and highlight the key issues for future investigations. A better understanding of the innate immune responses in xenotransplantation may help to control the xenograft rejection and design optimal combination therapies.

Beneficial effects of posttransplant dipeptidyl peptidase-4 inhibitor administration after pancreas transplantation to improve β cell function

Purpose

Dipeptidyl peptidase-4 (DPP-4) inhibitors lower blood glucose levels and enhance the function of pancreatic β cells. Yet, it is unknown whether posttransplant administration of DPP4 inhibitors is beneficial for pancreas transplant recipients.

Methods

We thus retrospectively analyzed the records of 312 patients who underwent pancreas transplantation between 2000 and 2018 at Asan Medical Center (Seoul, Korea) and compared the metabolic and survival outcomes according to DPP-4 inhibitor treatment.

Results

The patients were divided into the no DPP-4 inhibitor group (n = 165; no treatment with DPP-4 inhibitors or treated for <1 month) and the DPP-4 inhibitor group (n = 147; treated with DPP-4 inhibitors for ≥1 month). There were no significant differences in levels of glucose, hemoglobin A1c, and insulin between the 2 groups during 36 months of follow-up. However, the level of C-peptide was significantly higher in the DPP-4 inhibitor group at 1, 6, and 24 months posttransplant (all P < 0.05). Moreover, the DPP-4 inhibitor group had significantly higher rates of overall (log-rank test, P = 0.009) and death-censored (log-rank test, P = 0.036) graft survival during a 15-year follow-up.

Conclusion

Posttransplant DPP-4 inhibitor administration may help improve the clinical outcomes including β cell function after pancreas transplantation.

Lack of Improvement in Insulin Sensitivity After Pancreas Transplantation in Recipients With a High Level of Calcineurin Inhibitors

OBJECTIVES

This study aimed to assess posttransplant changes in insulin sensitivity and β-cell function of pancreas transplant recipients according to the type of diabetes mellitus (DM) and the pretransplant insulin sensitivity measured by the Matsuda Index (MI).

METHODS

We analyzed 60 patients who underwent pancreas transplantation and oral glucose tolerance test pretransplant and at 1 month posttransplant.

RESULTS

At 1 month posttransplant, insulin sensitivity did not show significant improvement; particularly, the MI was significantly lower after transplant in recipients with type 1 DM (T1DM) and those with pretransplant MI of 5 or greater. β-cell function was significantly improved after transplant in all recipients regardless of the type of DM and pretransplant MI values. Glucose control was significantly improved in recipients with T1DM and in all recipients regardless of the pretransplant MI values. Additional oral glucose tolerance test at 1 year posttransplant revealed that insulin sensitivity remained unimproved and β-cell function was higher compared with pretransplant. Glucose control had partially reverted to pretransplant levels in recipients with T1DM and those with pretransplant MI of 5 or greater.

CONCLUSIONS

Unlike β-cell function and glucose control, insulin sensitivity did not significantly improve until posttransplant 1 year after pancreas transplantation regardless of the type of DM or the degree of pretransplant insulin sensitivity.

Pancreas Retransplant After Pancreas Graft Failure in Simultaneous Pancreas-kidney Transplants Is Associated With Better Kidney Graft Survival

BACKGROUND

Simultaneous pancreas-kidney (SPK) transplant is usually the best option for the diabetic end-stage renal disease patient. There is limited information about kidney graft outcomes in SPK recipients with isolated pancreas graft failure who do versus do not undergo pancreas retransplantation.

METHODS

Patients were divided into 2 groups based on whether they underwent pancreas retransplant (ReTx+) or not (ReTx-). Kidney graft function and survival were the primary endpoints.

RESULTS

One hundred and nine patients satisfied our selection criteria, 25 in ReTx+ and 84 in ReTx-. Mean interval from SPK to pancreas failure was significantly shorter in the ReTx+ compared with the ReTx- group, 19.3 ± 36.7 versus 45.7 ± 47.0 months (P = 0.01), respectively. There was no significant difference in kidney graft follow-up post SPK between 2 groups (P = 0.48). At last follow-up, 15 of the 25 (60%) of the repeat pancreas graft had failed, with a mean graft survival among these failed pancreas graft of 2.6 ± 2.7 years, ranging from 0 to 8.1 years. Uncensored kidney graft failure was significantly lower in the ReTx+ group compared with the ReTx- group, 44% versus 67% (P = 0.04). Death-censored kidney graft failure was also lower in the ReTx+ group, 24% versus 48% (P = 0.04). The difference in patient survival did not reach statistical significance. In adjusted Cox regression analysis, rejection as a cause of pancreas failure was associated with increased risk of death-censored kidney graft failure, and pancreas retransplantation was associated with decreased risk of kidney graft failure. A similar pattern was seen after 1:1 matching for the interval between SPK and pancreas graft failure.

CONCLUSIONS

Even though ReTx+ patients accept the risks associated with repeat pancreas surgery, providers should consider this option in suitable otherwise healthy patients.

Long-term effects of pancreas transplant alone on nephropathy in type 1 diabetic patients with optimal renal function

Background

Limited data are available regarding optimal selection criteria for pancreas transplant alone (PTA) to minimize aggravation of diabetic nephropathy.

Methods

A total of 87 type 1 diabetic patients were evaluated before and after PTA at a single center from January, 1999 to December, 2015, together with 87 matched non-transplanted type 1 diabetic subjects who were candidates for PTA to compare deterioration of native kidney function. A total of 163 patients (79 in the transplanted group and 84 in the nontransplanted group) were finally enrolled after excluding nine patients with estimated glomerular filtration rate less than 60 mL/min/1.73 m² and two patients with moderate proteinuria (≥ 1.5 g/day).

Results

A total of seven recipients (8.9%) had end-stage renal disease post-transplant whereas only one patient (1.2%) developed end-stage renal disease in the nontransplanted group during their follow-up period (median 12.0, range 6–96 months) (p = 0.03). Furthermore, a composite of severe renal dysfunction and end-stage renal disease (31.6% vs 2.4%) was significantly higher in the transplanted group (p < 0.001). Multivariate Cox regression analysis revealed that a higher level of tacrolimus at six months post-transplant (HR = 1.648, CI = 1.140–2.385, p = 0.008) was the only significant factor associated with end-stage renal disease.

Conclusions

There is a considerable risk for deterioration of renal function in PTA recipients post-transplant compared with non-transplant diabetic patients. With rather strict selection criteria such as preoperative proteinuria and estimated glomerular filtration rate, PTA should be considered in diabetic patients to minimize post-transplant aggravation of diabetic nephropathy.

Long-term Metabolic Outcomes of Functioning Pancreas Transplants in Type 2 Diabetic Recipients

BACKGROUND

Limited data are available regarding the long-term metabolic outcomes of functioning pancreas transplants in patients with type 2 diabetes mellitus (T2DM).

METHODS

To compare the long-term effects of pancreas transplantation in terms of insulin resistance and β cell function, comparison of metabolic variables was performed between type 1 diabetes mellitus (T1DM) and T2DM patients from 1-month posttransplant to 5 years using generalized, linear-mixed models for repeated measures.

RESULTS

Among 217 consecutive patients who underwent pancreas transplantation at our center between August 2004 and January 2015, 193 patients (151 T1DM and 42 T2DM) were included in this study. Throughout the follow-up period, postoperative hemoglobin A1c did not differ significantly between T1DM and T2DM patients, and the levels were constantly below 6% (42 mmol/mol) until 5 years posttransplant, whereas C-peptide was significantly higher in T2DM (P = 0.014). There was no difference in fasting insulin, homeostasis model assessment (HOMA) of insulin resistance, HOMA β cell, or the insulinogenic index between the groups. Furthermore, fasting insulin and HOMA-insulin resistance steadily decreased in both groups during the follow-up period.

CONCLUSIONS

There was no significant difference in the insulin resistance or β-cell function after pancreas transplantation between T1DM and T2DM patients. We demonstrated that pancreas transplantation is capable of sustaining favorable endocrine functions for more than 5 years in T2DM recipients.

Allogeneic islet cells implant on poly-l-lactide matrix to reduce hyperglycaemia in streptozotocin-induced diabetic rat

OBJECTIVE

To demonstrate the effects of allogeneic islet cell matrix implants for glycaemic control in rats with induced diabetes.

METHOD

Sprague-Dawley rats were used as allogeneic donors of islet cells. Cells were seeded on three-dimensional proprietary poly-(l-lactide) matrices. Animals were rendered diabetic and a week later a matrix seeded with islet cells (IMI group) or a control matrix (placebo group) was implanted in the small bowel mesentery. Blood glucose levels were measured weekly for 12 weeks. After sacrifice, implant sections were Gomori stained for beta-cells and immuno-stained for insulin 3, 4, 5, and 6 months post implantation.

RESULTS

82% of seeded islet cells attached to the matrices. In the IMI group blood glucose levels were significantly reduced after implantation compared with before implantation across several time points. In the IMI group beta-cells and insulin-positive cells were identified at the implant site.

CONCLUSION

The islet cell matrix implant reduced the blood glucose levels although complete normo-glycaemia was not established. The islet cell matrix implant may serve as an additional option for islet cell transplantation using 3D scaffold platforms for better survival and function of the islet cells.

Lessons From Pancreas Transplantation in Type 1 Diabetes: Recurrence of Islet Autoimmunity

Type 1 diabetes recurrence (T1DR) affecting pancreas transplants was first reported in recipients of living-related pancreas grafts from twins or HLA identical siblings; given HLA identity, recipients received no or minimal immunosuppression. This observation provided critical evidence that type 1 diabetes (T1D) is an autoimmune disease. However, T1DR is traditionally considered very rare in immunosuppressed recipients of pancreas grafts from organ donors, representing the majority of recipients, and immunological graft failures are ascribed to chronic rejection. We have been performing simultaneous pancreas-kidney (SPK) transplants for over 25 years and find that 6-8 % of our recipients develop T1DR, with symptoms usually becoming manifest on extended follow-up. T1DR is typically characterized by (1) variable degree of insulitis and loss of insulin staining, on pancreas transplant biopsy (with most often absent), minimal to moderate and rarely severe pancreas, and/or kidney transplant rejection; (2) the conversion of T1D-associated autoantibodies (to the autoantigens GAD65, IA-2, and ZnT8), preceding hyperglycemia by a variable length of time; and (3) the presence of autoreactive T cells in the peripheral blood, pancreas transplant, and/or peripancreatic transplant lymph nodes. There is no therapeutic regimen that so far has controlled the progression of islet autoimmunity, even when additional immunosuppression was added to the ongoing chronic regimens; we hope that further studies and, in particular, in-depth analysis of pancreas transplant biopsies with recurrent diabetes will help identify more effective therapeutic approaches.

Original hypothesis: Extracorporeal shockwaves as a homeostatic autoimmune restorative treatment (HART) for Type 1 diabetes mellitus

Mononuclear invasion of Langerhans islet and the ensuing insulitis triggers signal-transduction for the autoimmune mediated pancreatic beta-cell (β-cell) apoptosis that severely disrupts insulin production resulting in hyperglycemia associated with Type-1 diabetes (T1DM). Today extensive global research is being conducted to eliminate the need for insulin, and even prevent or find a cure for T1DM. The multifactorial combination of autoimmune dysfunction, Langerhans islet hypoxia, and bio-chemical disruption are seen to be contributory factors for β-cell destruction and the consequential disruption to insulin production. Regeneration of β-cells back to physiological levels may restore homeostatic insulin levels, reversing T1DM. Evidence suggests that there are still functioning pancreatic β-cells even in long standing T1DM providing the potential for their regeneration. Although the exact mechanism of extracorporeal shockwaves (ESW) is yet to be fully elucidated, it is seen to influence a complex spectrum of bio-chemical, cellular and neuronal functions (i.e. suppression of pro-inflammatory immune response, improved tissue hemodynamics, anti-microbial properties, and the induction of progenitor cell expression including proangiogenic factors and nitric oxide syntheses). The rationale for the use of ESW as a therapeutic modality in this instance is attributed to its restorative properties and safety profile demonstrated in urology, cardiology, chronic wounds, osteogenesis, complex pain syndromes, and tendinopathies. ESW may restore autoimmune homeostasis creating a suitable environment for pancreatic β-cell proliferation which in-turn may significantly increase or normalize endogenous insulin secretion reducing or totally eliminating dependency of exogenous insulin. The devastating complications, morbidity and mortality associated with T1DM warrants the exploration of homeostatic autoimmune restorative treatment (HART) modalities that may partially or fully reverse this disease condition. We present our hypothesis discussing ESW as a potential homeostatic autoimmune restorative treatment (HART) option for T1DM.

Neurologic complications of pancreas and small bowel transplantation

In the past decade, substantial improvements in patient and graft survival for pancreas and small bowel transplants have been achieved. Despite this progress, many patients still develop neurologic complications in the course of their illness. Small bowel transplants produce more neurologic complications because of the complex metabolic environment in which the procedure is performed and because of the intense immune suppression necessitated by the greater immunogenicity of the intestinal mucosa. Pancreas transplants stabilize and/or improve the signs and symptoms of diabetic neuropathy over time. Because transplantation of the pancreas is often coupled with a kidney transplant and small intestine with liver, neurologic complications in these patients sometimes reflect problems involving the organ partner or both organs. The spectrum of neurologic complications for pancreas and small bowel transplant recipients is similar to other organ transplants but their frequency varies depending on the type of transplant performed.

Type 2 diabetes: is pancreas transplantation an option?

Transplantation of the whole vascularized pancreas can provide insulin secretion in patients with insulin-dependent, type 1 diabetes mellitus (T1D). It restores euglycemia in most patients, with the potential to impact the chronic diabetic complications and quality of life. Pancreas transplantation (PT) is presently controversial for type 2 diabetes mellitus (T2D). For those patients with severe glycemic dysregulation, T2D can be associated with the same life-threatening sequelae as T1D such as severe hypoglycemia and kidney failure that could be corrected by pancreas (and kidney) transplantation. Thus, clinical indications and patient selection criteria are very important. This chapter will review the current status of PT for T2D and discuss the options and evolution of transplant perspectives.

Present and future cell therapies for pancreatic beta cell replenishment

If only at a small scale, islet transplantation has successfully addressed what ought to be the primary endpoint of any cell therapy: the functional replenishment of damaged tissue in patients. After years of less-than-optimal approaches to immunosuppression, recent advances consistently yield long-term graft survival rates comparable to those of whole pancreas transplantation. Limited organ availability is the main hurdle that stands in the way of the widespread clinical utilization of this pioneering intervention. Progress in stem cell research over the past decade, coupled with our decades-long experience with islet transplantation, is shaping the future of cell therapies for the treatment of diabetes. Here we review the most promising avenues of research aimed at generating an inexhaustible supply of insulin-producing cells for islet regeneration, including the differentiation of pluripotent and multipotent stem cells of embryonic and adult origin along the beta cell lineage and the direct reprogramming of non-endocrine tissues into insulin-producing cells.

Advantage of rapamycin over mycophenolate mofetil when used with tacrolimus for simultaneous pancreas kidney transplants: randomized, single-center trial at 10 years

Simultaneous pancreas kidney transplantation (SPKT) is the treatment of choice for patients with type 1 diabetes and end-stage renal disease. Rapamycin and mycophenolate mofetil (MMF) have been used for maintenance immunosuppression with tacrolimus in SPKT; however, long-term outcomes are lacking. From September 2000 through December 2009, 170 SPKT recipients were enrolled in a randomized, prospective trial receiving Rapamycin (n = 84) or MMF (n = 86). All patients received dual induction therapy with thymoglobulin and daclizumab, and low-dose maintenance tacrolimus and corticosteroids. Compared to MMF, rates of freedom from first biopsy-proven acute kidney or pancreas rejection were superior for Rapamycin at year 1 (kidney: 100% vs. 88%; P = 0.001; pancreas: 99% vs. 92%; P = 0.04) and at year 10 (kidney: 88% vs. 71%, P = 0.01; pancreas: 99% vs. 89%, P = 0.01). The higher rates of rejection were associated with withholding MMF (vs. Rapamycin, p = 0.009), generally for gastrointestinal or bone marrow toxicity. There was no significant difference in creatinine, proteinuria, c-peptide, viral infections, lymphoproliferative disorders or posttransplant diabetes. HbA1C and lipid levels were normal in both groups, although higher in the Rapamycin arm. There were no significant differences in patient or allograft survival. In this 10-year SPKT study, Rapamycin in combination with tacrolimus was better tolerated and more effective than MMF. Overall, the patient and allograft survival were equivalent.

A novel technique of portal-endocrine and gastric-exocrine drainage in pancreatic transplantation

BACKGROUND

Pancreas transplant (PT) is an established treatment for patients with diabetes mellitus. Diagnosis of rejection has continued to be problematic. In 2007, a new technique of PT with gastric exocrine (P-G) drainage was first performed at our institution. This technique facilitates access to pancreas allograft. The purpose of this study was to compare our experience with PT using P-G technique and the technique of portal enteric (P-E) with venting jejunostomy.

STUDY DESIGN

Thirty patients who underwent PT between 2007 and 2009 (G-I) and 30 consecutive patients before this time (G-II) were studied. In both groups arterial and venous anastomosis was similar to standard P-E technique. In G-I, the end of allograft jejunum was anastomosed to the anterior aspect of the stomach. In the G-II, allograft duodenum was anastomosed to the Roux-en-Y and end of Roux-en-Y was brought out as venting jejunostomy.

RESULTS

Donor and recipient demographic data, number of antigen matches, and immunosuppressant were similar in both groups. All patients achieved euglycemia. In G-I, 3 patients underwent pancreatectomy, 2 owing to vessel thrombosis and 1 owing to chronic rejection. Two patients died with functioning pancreatic allografts. In G-II, 1 pancreas was removed owing to vessel thrombosis. Seven patients with cytomegalovirus and 4 patients with rejection in G-I were diagnosed with endoscopy of allograft duodenum. One-year patient and graft survivals were similar.

CONCLUSIONS

This technique has proven to be safe with good patient and allograft survival. Access to donor duodenum and pancreas allograft via endoscopy is unique to this technique and provides the added advantage of life-long easy access to allograft.

The isolated pancreatic islet as a micro-organ and its transplantation to cure diabetes: celebrating the legacy of Paul Lacy

Over the past three decades the pancreatic islet of Langerhans has taken center stage as an endocrine micro-organ whose glucoregulatory function is highly explicable on the basis of the increasingly well understood activities of three highly interactive secretory cells. Islet dysfunction underlies both type 1 and type 2 diabetes mellitus (DM); its protection from immune attack and gluco-and lipo-toxicity may prevent the development of DM; and its replacement by non-surgical transplantation may be curative of DM. During a career marked by vision, focus and tenacity, Paul Lacy contributed substantially to the development of each of these concepts. In this review we focus on Lacy's contribution to the development of the concept of the islet as a micro-organ, how this foreshadowed our current detailed understanding of single cell function and cell-cell interactions and how this led to a reduced model of islet function encouraging islet transplantation. Next, we examine how clinical allotransplantation, first undertaken by Lacy, has contributed to a more complex view of the interaction of islet endocrine cells with its circulation and neighboring tissues, both "in situ" and after transplantation. Lastly, we consider recent developments in some alternative approaches to treatment of DM that Lacy could glimpse on the horizon but did not have the chance to participate in.

Octreotide attenuates impaired microcirculation in postischemic pancreatitis when administered before induction of ischemia

BACKGROUND

Ischemia-reperfusion injury of the pancreas causes impairment of microcirculation leading to pancreatitis. Postischemic pancreatitis is the most common reason for graft failure in pancreas transplantation. In animal models, octreotide has been described to have beneficial effects on acute pancreatitis by reducing pancreatic enzyme release and edema formation by preventing the increase of macromolecular extravasation. In contrast to earlier experimental setups, this study investigated the influence of octreotide on ischemia-reperfusion pancreatitis when administered before induction of ischemia.

METHODS

Sprague-Dawley rats were randomly assigned to three groups: (1) sham-operated animals (sham group, n=7); (2) 1 hr ischemia followed by 1 hr reperfusion (control group, n=7); (3) administration of 50 microg/kg octreotide intravenously 15 min before ischemia (octreotide group, n=7). At the end of reperfusion, intravital fluorescence microscopy was performed assessing the functional capillary density (FCD), leukocyte-endothelium interaction (LEI), and the microvascular permeability. Finally serum amylase and lipase were measured.

RESULTS

The application of octreotide significantly reduced the ischemia-reperfusion-induced reduction of FCD (318.4+/-44.1 cm/cm vs. 257.4+/-11.7 cm/cm, P<0.001). The increase of LEI due to ischemia-reperfusion (466.9+/-52.2 cells/mm) was reduced in the octreotide group (264.4+/-55.1, P=0.001). Permeability was significantly lower in the octreotide group (0.56+/-0.57x10 cm/sec vs. 2.2.1+/-0.54x10 cm/sec, P<0.001). The level of serum lipase was reduced significantly after octreotide therapy (72.4+/-53.4 U/L vs. 136.7+/-66.5 U/L, P=0.026).

CONCLUSION

Octreotide significantly attenuated pancreatic dysfunction caused by ischemia-reperfusion when given before ischemia. Furthermore, we could prove for the first time a beneficial role of octreotide on preservation of the microvascular barrier for macromolecules.

Retrospective assessment of islet cell autoantibodies in pancreas organ donors

OBJECTIVE

Of deceased pancreas donors, 3-4% may have autoantibodies (AAb) to pancreatic islet cell antigens; these autoantibodies are well-established markers of type 1 diabetes. We investigated whether donor AAb positivity could affect the outcome of pancreas transplantation.

RESEARCH DESIGN AND METHODS

We retrospectively tested AAb in 135 donors whose pancreata and kidneys were transplanted in type 1 diabetes patients. We measured AAb to glutamic acid decarboxylase (GAD-AAb), the tyrosine-phosphatase-like protein IA2 (IA2-AAb), and insulin (insulin-AAb). We then evaluated pancreas transplant outcome data.

RESULTS

Four of 135 (2.96%) donors were AAb positive: three donors had GAD-AAb, and one donor had insulin-AAb. Their respective recipients became insulin independent on follow-up. Three of the four recipients had normal, insulin-producing grafts 3-5.8 years after transplant. The recipient of the insulin-AAb-positive donor pancreas developed chronic rejection following discontinuation of immunosuppression 3.3 years after transplant.

CONCLUSIONS

Single AAb positivity did not affect the outcome of pancreas transplantation in our study.

Type 1 diabetes: pathogenesis and prevention

Type 1 diabetes results from the autoimmune destruction of insulin-producing beta cells in the pancreas. Genetic and, as yet undefined, environmental factors act together to precipitate the disease. The excess mortality associated with the complications of type 1 diabetes and the increasing incidence of childhood type 1 diabetes emphasize the importance of therapeutic strategies to prevent this chronic disorder. Why is it considered that type 1 diabetes might be preventable? Different strands of diabetes research are coming together to suggest therapeutic targets. Islet cell autoantibody assays make it possible to accurately identify people at risk of future disease. In most cases, a long prodrome provides a window of opportunity to reverse the autoimmune process. Although no current "cure" exists, recent genetic data and preliminary trial results suggest T cells as a target for preventive strategies. Another potentially attainable target is induction of tolerance to the beta-cell proteins such as insulin that are inappropriately recognized. Other strategies involve beta-cell replacement, but currently there are insufficient donor cells available. This may be overcome as the processes controlling the differentiation of pancreatic and nonpancreatic progenitors as well as replication of existing islet beta cells are unravelled.

Morphological and functional characterization of a pancreatic beta-cell line microencapsulated in sodium cellulose sulfate/poly(diallyldimethylammonium chloride)

BACKGROUND

Late diabetic complications cannot be prevented totally by current antidiabetic strategies. Therefore, new therapeutic concepts of insulin replacement such as pancreas transplantation are evolving. Due to the shortage of human donor organs, transplantation of microencapsulated xenogeneic pancreatic islet cells has attracted considerable attention. Sodium cellulose sulfate/poly(diallyldimethylammonium chloride) (NaCS/PDADMAC) is a material with favorable biogenic properties that has been used for microencapsulation of various cell types. However, there are no data on the suitability of NaCS/PDADMAC for microencapsulation of pancreatic beta-cells.

MATERIAL AND METHODS

Cell growth and viability of NaCS/PDADMAC-microencapsulated HIT-T15 cells, an immortalized hamster pancreatic beta-cell line, were assessed using a dimethylthiazol-diphenyltetrazoliumbromide (MTT)-based cell growth determination kit and apoptosis was detected by antibodies against activated caspase 3. Glucose-dependent insulin secretion was assessed with ELISA and the uptake of glucose was measured using fluorescence-labeled glucose.

RESULTS

Statistical analysis revealed no differences in glucose-dependent cell proliferation, insulin secretion and glucose uptake between non-microencapsulated and microencapsulated HIT-T15 cells. Stimulation of HIT-T15 cells with glucose (100 mg/ml) resulted in a biphasic insulin secretion response.

CONCLUSION

Microencapsulation of HIT-T15 cells in NaCS/PDADMAC does not influence cell proliferation, insulin secretion and glucose uptake. Our results indicate that NaCS/PDADMAC is well suited for microencapsulation of pancreatic beta-cells.

Clinical evolution of diabetic rats after transplant of electrofused pancreatic islet cells and dermic cells

This work was designed to study an alternative treatment of diabetes mellitus by using a transplant of hybrid cells obtained by the electrofusion of pancreatic islet cells from a healthy donor with dermic cells obtained from a recipient. The hybrid cells kept the capacity of insulin production, its regulation, and the natural control of glycemia, as well as the factors of histocompatibility to avoid the rejection. Four groups of four rats each were established: Group 1. Healthy animals (healthy control), Group 2. Diabetized non-treated animals (diabetic control), Group 3. Transplant recipient rats with extraction of dermic cells which were mixed with pancreatic insular cells from a healthy donor (transplant without fusion), and Group 4. Transplant recipient rats, with extraction of dermic cells which were electrofused with pancreatic insular cells from a healthy donor (transplant with fusion). For the Group 4, the cells were combined and they were submitted to dielectrophoresis conditions with an alternating current pulse of 15 s of 10 V RMS of 0.5 MHz. The fusion was made with a direct current pulse of 1 ms of 300 V. Clinical signs were registered (weight, diuresis, food and water intake), and several biochemical parameters in blood which included basal glycemia, uric acid, cholesterol, triglycerides, glutamate oxalacetate transaminase, glutamate pyruvate transaminase, urea, creatinine, insulin, glycated hemoglobin were registered. Additionally, ketone bodies and glucose were also measured in urine. All determinations were made at 30, 60, and 90 days. Animals of Group 1 maintained its parameters within the normal ranges. Rats of Group 2 presented alterations corresponding to a diabetic state in almost all the parameters measured, none of the animals showed a tendency to improve spontaneously, two of the rats died at 66 and 72 days. The Group 3 showed a clinical profile similar to the diabetic control group without improvement, only one rat died at day 33, while in the rats transplanted with fusion (Group 4) an improvement was observed on some parameters including body weight, water intake and glycemia. Although insulin concentration was under the normal range, it was higher than in the Group 3. None rat died. These results indicate that it is possible to improve the diabetic profile by the transplant of dermic cells from a diabetic animal fused with insular cells from a healthy donor in the recipient animal.

Quality of Life After Simultaneous Pancreas–Kidney Transplantation

Even recipients with satisfactory function of transplanted pancreas and kidney may show physical and/or social disability due to diabetic complications. Our aims were to evaluate diabetic complications influencing recipient quality of life and to assess patients' psychosociological status. Nineteen patients with functioning grafts who consented to take part in the study, underwent clinical evaluation and answered questions regarding their quality of life. Results showed excellent endocrine pancreatic function in 17 patients. In most recipients, insulin activity and C-peptide levels were elevated owing to systemic venous drainage. Opthalmological examination revealed blindness in 7 patients (in 4 cases with onset following SPKTx) and retinopathy in 13 patients (in 5 cases it appeared after SPKTx). Assessment of the cardiovascular system revealed satisfactory cardiac function in 16 of 19 patients; 4 patients underwent amputation of a lower limb following SPKTx. All 19 recipients admitted to a great benefit of transplantation; most patients declared ability to organize their life activity and social functions and 4 had regular employment. Conversely, most patients were afraid of graft loss, and half were often sad and even depressed.

The beneficial effects of pancreas transplant alone on diabetic nephropathy

OBJECTIVE

Pancreas transplant alone can be effective in significantly improving the quality of life of type 1 diabetic patients, and it can also eliminate acute diabetes complications, such as hypoglycemic and/or hyperglycemic episodes. The effects of pancreas transplant alone on long-term complications of diabetes, including nephropathy, are still not settled. We evaluated whether restoration of long-lasting normoglycemia by pancreas transplant alone might have beneficial action on diabetic nephropathy.

RESEARCH DESIGN AND METHODS

A total of 32 type 1 diabetic patients were evaluated before and 1 year after successful pancreas transplant alone, together with 30 matched nontransplanted type 1 diabetic subjects. Several metabolic and kidney function parameters were measured, including plasma glucose, glycohemoglobin (A1C), C-peptide, plasma lipids, blood pressure, creatinine, creatinine clearance, and urinary protein excretion.

RESULTS

Pancreas transplant alone restored sustained normoglycemia, without exogenous insulin administration, and improved plasma lipid levels. Blood pressure decreased significantly. Creatinine concentrations and clearances did not differ before and after transplantation. Urinary protein excretion decreased significantly after pancreas transplant alone, with four microalbuminuric and three macroalbuminuric patients who became normoalbuminuric. None of these changes occurred in the nontransplanted group.

CONCLUSIONS

Successful pancreas transplant alone, through restoration of sustained normoglycemia, improves diabetic nephropathy in type 1 diabetic patients.

Roles for bone-marrow-derived cells in beta-cell maintenance

With more than 177 million people suffering from diabetes worldwide, and the number expected to double by 2030, finding new ways to treat this disease is a high priority. Intensive effort is being directed towards developing mechanisms for increasing beta-cell expansion as a diabetic therapeutic. Recent studies, in which adult bone marrow has been used to induce beta-cell expansion in mice, have shown both exciting and controversial results. In these reports, marrow-derived cells can contribute towards beta-cell maintenance both by promoting endogenous beta-cell expansion and possibly by transdifferentiation into beta-cells. These studies reveal mechanisms for potential therapeutic intervention.